molten-salt reactor program
TRANSCRIPT
- - zcy ORN15078
MOLTEN-SALT REACTOR PROGRAM
Semiannual ^ogness ^cpoit
^P^iod Surfing August 211975
MASTER
OAK RIDGE NATIONAL LABORATORY
1 I bull i
BLANK PAGE f4
bull f
Printed in the United States of America AnaiMMc from National Technical Inforniotion Service
US Deportment of Commerce 5286 Port Royal Road S o r - ^ Virynia 22161
Price Printed Copy SampSOMicrofche $225
I M V taporf laquopaw pranwas at an aocpaar a a w ajaaaaran a 001 latajaa aanai
Ada^unr0oon nor aft of ^bullJw onolovaaa tiar ooy of tfJaw connractors aabxonaaciors or insa anaaloapnv faonas an oaavrantv noorav o nooaoaV or
WBaransaaa fatrade bull P ^^raquo^aoo(r ajaww Rwgtgtraquo bullbullbull WMPCI a pr PEaa RK^PJWgt ar ranrfraquofmwww ttrnt I B uaf ajovaj not awKfaja prrtnjajh oamotf rtojm
U C 7 raquo -
CoMfKlMo
RMKMOO MMucrsiifii
LE
FENUAftY 1976
OAK RIDGE NATIONAL LABORATORY Oak R 4 T O T M H W 37W0
opwaNdby UNION CARMX CORPORATION
forffw ENERGY RESEARCH AND DEVELOPMENT ADMINISTRATION
MASTER V
~r -ruic rvVUMENT IS UNLIMITED WSTWBUTION OF THIS DucUWttrade ^
1 M Mpoct raquo olaquoc laquorf x laquornrraquo v4 IMA MIMA Weuro M C I MIO
i t a k trpoffe iHji AcwriM tnr ptoyrc bullgt the (aopun Ilihrgt c^wt i==v agt
0 laquo M 4 4 K M bMg 1 M V gt 31 Ilaquoraquo O K M - raquo tow (aMj CViltn 31 W ( K M X U total E M M J laquorgt 31 I OlaquoM raquo tow IKM laquolt gt-iraquo 0laquoM7raquo tonJtJMMfMgt3lllaquo5laquo ORMOSlaquo tnaikmtmtOctlt+tt HI (MSI m D m (tthnj teraquogt 3I JMI ii 30 |ltlaquo0 OKM-3QI4 tomJ fattMf Mgt 31 IlaquoMO ( K M 31 towi fawMf Frmgt gt Iltl OHM 321 lt towrftJMMf AMMM3I Ilaquoraquo OmSLi^Z total FMIMJ Hbrmay gt bull- ORM-334 tomt tJnf AMWlaquo 31Ilaquo ORM-34P to MOM Jmraquogt 311laquob3 0laquoL-35gt totaj tMJwf JMgt 31 IMJJ ORM-3raquogt towl EMM tani 31 fM O t M r rrd M Mgt 311laquoM OHM-3 I towJ to FVfrfwry 3gt bullbulllt OKM-sraquo total EMM laquo laquo i 31 Iltraquolt ORM-gt3b totaJ EMM F4MMgt gt IlaquoraquoM ORM-K~ to vlaquo MAM M J1Ilaquoferaquo G4LM4I J tow EMM i n laquo gt raquo I W OHM-raquobullraquo ftnud EarfMf Ailaquow4 3 bullraquo aM-raquolaquo4 toraquoi E M FlttNlaquoHgt i OHM4344 total EMJH Ktfmt 31 IltM OftM-ll towi EMJM FfMfgt gt Ilaquoraquoyenraquo ORM444 totaJEiMJ3llltraquo OfcM 444ft toml Eraquofc F4WlaquoM gt I OftM4j total b u b tmgmt 31 laquobull OftM467 feftal EMJM Flaquofcrmv bullraquo Ilaquo7l 0RM4gt total E n 31 I7| OftM47iC torn EMM Flaquoflaquoy -^ llaquoraquo OXM4K3 total EMM AapM 31 17 OftNL-5011 total EMM AMlt 31 I4 ORM-ttM towl E n FlaquoraMgt gt W
Coimnti
SUMAftY
PARTI mm KUCM Aim vcvujonmsj t v^SItMS AND ANALYSIS 2
raquo l n t t raquo bull ( bull bull laquo a Mete SJpound nam I I M 5 M C J U I M raquo 2 1 I r laquo 4 w t Srfl TlaquodMc4ap FMhn 3
I 2 amp w Rftowr raquo laquo sect bull 1 3 mroMi Aaalyws - 9
131 MSMSnrgt 9 l raquo TXr tCraquoo 12
14 t t^TcnpctsnMrDNpi I te fe 12
2 s m t J t S A X P C O I 0 9 ^ T S 0 m U gt r M L T 16 21 l t -Sgtnn TfdMofofy Fac 16
211 Crwraquomwiw4$rfihmdashySgttnOfcltjtiraquowi 16 2 12 S-ftowraquo^vfuiwHWif DWraquo3MCJamiilaquoirfVjnjWrnuwteimcraquogtn IS M M N ^ F laquo W M I F W 19 214 P w i mtmmiH 22
2 2 Claquo4aM-Sak T laquo f c raquo w F n iCSTFl 22 22 1 UvOMYJCM 22 2 2 M M M T M 23 223 TIMM Ei^tiMm 24
23 Ftwcrtf rlaquonlaquocimi Lon^sect 2 23 1 0prraquoiMigtfMSR-FCl-2raquo 26 231 DtwptmiCamnKnmafKVymtifCL 2
PART 2 IMLMSIRV
3 FUEL SALT CHEMISTRY 29 31 C n y i i i mttkt Lirtitmdashi Trfcinw Syami 29
3 Sprctrawoyy of Tcnprtan Sptctn n Manni Swu 30
3 3 Thr UrjMHMi TrirjIWori - H y d w y Ci|iiraquonmdashi m Matio Fhwnic SahMww 31
34 Fwam EJrctra S w laquo n laquo Mate Salts 32
35 Flaquo4 SafcladMi Sad lmnmttm Snafcn 34
36 Laiiior mamp FOWMHUH LJuMptcs of Fw-Ro TraMOc Meld Fbariafcs 37
ii i
IV
4 COOLANT SALT CHEMISTRY 4 4J ClKMtfiY ut SUAMW Ftourakcwa 41 4 2 CorrusmofStiuvinralAloysby Fmoroboraies 42
5 DEVELOPMENT ASD EVALUATION OF ANALYTICAL METHODS 44 51 m4aKAnafestraquo of Molten MSMtFnel 44 52 Tntmni A t f M Esperanents bull t Coutat-Salt Tedhnofagv Facnfcty 45 5J Ekctnlaquo^Kfic^Si^Maflralaquoll|aiMahaiLi -BeF -TM laquo
( T M 6 - i laquo ^ l 47 5 4 Vidummetnc Sankes of Tdnmnn m Molten LnT-BeF -ThT
lt2I6-I2 bull-gt 48
PAST 3 VUlERlAI^ DEVELOPMENT
6 DEVELOrMENT OF MODIFIED HASTELLOYN 52 61 DewelapinesM olt a Moitei Sait Test Fscdicy 52 62 rVocnmneai and Fabrication of Experjnental Almi 65
6-21 Production Heatsof 2 TiJIudrtied HasieRoy X 65 622 SltMfraquooictraquoltNi Keats of 2t TtModmcd H s N
Cammm Stdbmm 6raquo 6J WeMabiny afCanneTcni AlowgtModified HastetVn N 69 64 SUDdm of V m w Modified Hmrikn N Aloys m me
L nnf jdmed Condition 74 65 Mtdumcai Properties of Tiljmdashw Modified Hasietttn S Aloys
bull nW Umnndnied Condition 7 66 IVMirrsdnmn Creep Properties of Modified Kxuelloy N 82 6 7 Mkratntctwral Anah-raquos of Tnawm4lodified HastetVn N 84
671 MKroMracwnl Analysis of ABoy 503 and 114 85 672 HomopefctotisHastctoy S Aloys 88
6Jraquo Salt Corrosion Sindies 91 681 Flaquoe Silt Thermal Convection Lraquoraquops 93 682 Foci Soil Forced Circulation Loop 94 6 J raquo 3 CoolaMSalt Tfcennal ConvectionLoop 94
69 Corrosion of Hasaenm N and Otner Aloys m Steam 97 610 Observations of Reactions n M-talTeiliinum^i System 100 611 Operation of MetalTeHvnam-Salf Systems 101
6111 IHkumm Experimental put gtunVlt I 101 6112 Oironnnm Telunde Snfcmrfity Exprnmer 102 6113 Temjnwrt Experimental Pot Number 2 103
612 Gram tnawdary Embrittleinenl of Hasteiloy N by TeHuriwn 103 613 X-Ray Identification of Reaction Products of Hastetloy N
Exposed to Trikimm-CnnianMnit Eimromrents 107 614 MetaflografnW Exammatmo of Samples Exposed to
Telwnum-Canianwnii Environments 108 615 Examination of TeGcn-l P 119
6151 MeialopaphK Observations 123 6152 Chermcd Analyses for Temirium 124
V
fc16 Salt Prepantni aad Fad Fm Fafelaquo for TEGea-2 aad -3 131
7 FUEL PROCESSING MATERIALS DEVELOPMENT 132 71 SUCK CapMkTlaquob of Gfwhile with BoHMka^
bullKawm-Lrifcaaa SUMIMMK 132 7 2 Thermal Grlaquoaer Maraquo Transfer T laquo of Graph
maMofcMeaamLoap 133 T2I Wea^tChanan 133 722 Coaa^sttoaalCkaaats 133 f23 MkroMractwraiOnagri 137 7 24 DBcmsHN of Rente 37
PART 4 FUELPROCESSMC FOR MOLTEN-SALT REACTORS
a ENGINEERING DEVELOPMENT OF PROCESSING OPERATIONS 142 HI Metal TransferProcessDevelopment 142
111 Addrtion ltM Safe and turna Pka^ ir Metal Transfer Experanezi MTE 3R 143
12 R M d-l 144 a13 R raquo V 145 al 4 DrwwKM of Remits 145
a 2 Saftntoaiwir Contactor Dewdopmenr 147 H21 Lxpeirnents with a Mechanically Agitated Nnnitiprnwi Contactor
bull ike Sah-Ruamth Flowthronfi Facaify 14 a2 Evperiments with a Mrdumcafry Agrtatcd Vindiipri mi
omactor Una water and hVrcury 149 H3 Contavjoas Fhjonaator Devdopmert 152
a3 I histatbtion and Initial Operation of Autoresittance Heatmi Ten AHT4 152
a 3_ Drsam of aCoatamons Fuonaator Expenmeat Facdny iCFEFl 155 K33 Hmonme Disposal Sync for Md 7503 156 H4 Frozen WalCorrosion Protection Demonstration 156
a4 Fad Recnnstifation Enpneernt- Development 15 H41 Imtnaneniatton lor Anatynap Reaction Vessel Off-Gases 15a a42 Deng of the Second Fact Reconstitaoon Eapneermc
Experiment 160 85 Conceptual Deagn of a Mjlten-Salt Breeder Reactor Fad
Processing Engiaeermg Center 161
PART S SALT PRODUCTION
9 PRODUCTION OF FLUORIDE SALT MIXTURES FOR MSR PROGkAM RESEARCH AND DEVELOPMENT 163 91 Quantifies of Salt f-rodaced 163 92 Operating Experience in l2-m-diam Reactor 163
921 Charging and Mrfimg ltA Raw Materials 164 922 Hydrofluorination and Hydrogen Reduction 166
93 Summary 166
ORGANIZATION OIART - 167
PAST I h B M D E 5 raquo r a AND DEVELOPMENT
J REnael
I Srsvcavaad AmJrait
CaVnaatnms c4 the expected trnmm tcknor in refoessce-deagn MSMt a m loatmuid wall stmVcs of the uoanbte effects of ovale rams on heat ex chaff surfaces in the steam system and on surfaces exposed to the ccmaimmtm atmutawew The presence of oxide A n vjnraquoH laquoery km ptimubmty on the heat toaster surfaces would SMstnVaaey reduce the rate of intmm nwgrgrion to the steam system became of the mciemmg importance laquoltf the oxide-Am resistance at very km parshytial pre a w i of hydrogen and irnnaa l lowexi the reduction irom this effect alone would be rnuufficieut to heat rbe rate of tritiuui msginion to the steam system t J denied tames At rates ltd tritium irans-pori le the steam system the presence of oxuk-fam rcastatccs ltm loop wait tends to mcrease the rate of frinsra Hem mto the steam However tins effect a mukpufkaat at the low migiatiiw rates required
Potential ^inbwuonj of tritium m the ruotmt-Snh Technology Facmty were estimated for the cundrtmus o planned expenments In the absence of inborn rater-^ctioe with the salt other than mnpk ihisututici as ranch as laquoW5 of the added tnthaa cowU be expected to escape through the loop wals Removal of significant fractions in the loop off-fas coaM he expected uaH i the effective permeabmty of the loop watts were 10 to 100 times less than that of bare metal
Substantial chemical interaction of tritium with Nnaf 4-NaF was observed in the two tritium addition tests performed Ratios of cornbmrd-to-efcmnilal tritshyium in the salt inferred from elemental concentrations in the off-fas and combined concentrations m the sail were 50 and 530 for the two tests Approximately pound to of the dded tritium was removed in the off-gas stream prindpaly in a chermcaay combined water-soluble form
An undated aeutromes modrl raquot the lOOv-Mtftci releteace-dcsam MSMt r heme developed Muhi-duneanuaat mntagioap cakwUtmas wdi me the VENshyTURE code with newt run crosfsectson data dented catNcK from the fcNDF-IV Wwantv Pruoriune bull the croavteefMW dau was completed tor 3 otJraquo nachdo at lorn temperatures gtJt mtemi lot the planard cakvb-i m v Crow-stetson dau are also heme exammed it the two-step thenaai reaction Nangtr lt Naij i lrf winch is expected ilaquoraquo be the principal to sxe ot hebum m MSMt stractaral metals
A review of i he dau and cakubtsuns medio estauatc tdtunwe mveutories m the TeGen-l experMKM m-catesanuaccTtamtgt ltbull Xr
Work raquo contmaHNj raquo the udgt bullgt thrruul rotvh-ettmg and creep fafaw m react vtrwctural nuternh Analytical ractbodS are bemg developed which wdl be apphed Ss reference-design MSMt ilaquogt evaluate the significance of these processes m HattePoy N
The (ins-Systems TechnoVigy racdtty was ilaquoperated with water throughout the report ptnod Efforts to reduce the annua um ltH the salt-pump shaft oscdbtiom have been unsuccessful The jmyunudt of these oscdb-tions rs brgety dependent upon vk laquoi w ed so a bger-dhmeter imprler which wnl give the design flow and head at kmer speeds rs heme fabneated A method was developed for estimating the pump fountain flow Smce this flow was higher than desirable bach vanes wtl be used on the new rmpener o bnui the How Tests made at the loop indicate that the densnometer can be used to determine bubMe-sepiralar efficiencies if short-term tests are used
Routine operation _ltf the (oobnt-Satt Technology Facility was esiaMrshrd with more than 50Ghrof sah circidation without plugging in the loop off-gas Nne Measurements of the amount ot salt mist in the off-gas stream showed 100 to 500 ngcm iSTP) depending on
VII
1 M
w
l t
I BLANK PAGE
bull-laquo-
laquo t u
the a l t temprrataK and the I F flow rale MMO ike loop gas space The M M trap awtaard m the sah cold trap was effectn m meanta ike pm^mg hraquot had been expeneaxd earner Two i m i a marcoon lesti bullere coadacteJia whjch 85 aad bullraquo cwTi teaarvtwds of ifitmed bydropea ere added to the loop dame two I04raquo periods- Ficqaeat n i l aad off-gas sample were takea to mumlor the tRtaaa bebamor m the kwp
The torcedltoarctwa loop MSat-FCL-2b has accw-rautatcd MOO hi of oneratnaa with MSMl reference hart vdi at deaf ^ r coadmoas wrm riW expected low O M -roaoa rates Dbu oMaawd oa the beat master ckarac-terufacs of das sak air being aaafvard The deaga B eaeaadK complete for torced-coawectioa loops FCL-3 aad FCL-4 Coaaaoaeats ate beaaj fabricated J dec-tncal a i i f lHwia is proccediag
PART 2 C V E M S n t Y
3 Fari-MtCfceaaMry
Refachch pare Li Te lahoat lt oa a mole haasi bullas piipaatd by the coatroaedaddrooaof Kaaraaa to Hiaad hdnum The lac tam was began at 15QT bat afciamefjr tempt Mimes greater thja 50tTC acre reshyquired to complete the reactwa LiTe was prepared by rcactmg the aoidaomrtric amounts of LijTe aad tcfa-raan f o r brat 550^0
Apparatus for the spectroscopic stady of letunam species ia MSMt far salt has beta aaeaawed rYeima-nar work am hnmaa teshmars ia cbkmde taehs has shown ant at least two Mfbi-abjurbaig spears are present wirh uwapoatuai at the raja Li-Te to UTe Farthenaorc stadia with T e ia LiO-KCI eatectic have shown that laquo addition to Telaquo a lecoad species is present at high lemperatewH aador lag habie km activity
Apanxtm for the qtearoihotometric stady of the conawriam UFlaquo(dgt bull 4H 2 iggt = UFidgt bull HF|graquo has beea assembled aaa measurements using LiineF as the sointnt haw begaa A prehaaaary valac of aboat 10 was obtaiacd for the eqiaktiiam quotient at 6S0degC Tins vaiae is ia good agreement with the valat obtained pnwoady by other workers
Detopmeni proceeded on porous aad pact d-bed electrode systems as coatiaaoas on-line moailors of conceatralioas of declroactiwt species in molten sail solutions The packed-bed electrode of glassy carbon spheres was caNbralaquo4d using Cd 1 ions in LiCI-Kfl eutectk before experiments were conducted with B ions in solution The results of the experiments demon-straied the cpabdity of the electrode for momioring these and other ions
Preunaaary eiftrraacar i n c conducted iraquo cvatiaic watt ^wntkKM fetatmg to the naxmg bullbulllaquo VaBr - jF coutaai sah with M S M tiid vdi D F - f k f - H i r 4 F tMfc-ll ~-0S mute I Ibe result showed that ihr rate of erutatjoa oi BF gas raquoa naxau was low Mi vac of sanf amounts m coolant vdi wtth fael tab Jal bulllaquo result at the purctpttatam M aramam- ltlaquoc ibiwaaa-coataaaac -antpuands Vlt data w^re abtaaed +m ibr aaxaa M sanfl aaamats ot farl salt wwh o4aM vW( HesahstHeiprraataiiMi whvh a satal amtaai ot on-l aat salt cuataaaay igtxale was aaed with tael salt sae-eraed d m oude speoes aawe stable dun I O wlaquotc pMseat smce bullgtraquo pitecipitjnua of I O was raquodraquosrtraquool
A stads ul laztice eadadaKs ot tirst-ruw traassfiua-atrial (Wndcs was aadertakea to proadr a theraquofciicjl basts laquobullraquo ii itll Haw thrnancbrnacal data Urn uraLiaial metal tlaondes bratg obtaated from mm4 eitctrcisie gjiiaaJL ceKs I igaadnrid comctamsto pkxsul lattKe emhapy laquos ttnaat aamber for the rwraquoraquo senes CaF laquoo laFz raquo ScFgt to GaF mdkaied that dte staadad embdptes at loranfua plusmntf gtol N jad V F weilaquo saostaclors bat dial a m accante expcraaeatal lamn of Sit fur T i F V F O F CrF F e f aad FeF woald be deswabh
Analysrs tlaquot raaplr i ot coaJeasate coarcted danat opnaiwa of the Cooba SJ Tccbaolagy Facigt nahcate that the mpur aboar the gtali B aot a taaie mokvafar coeapoaad bat rather a auxtarc ot stamk gateows species sach as H 0 HF aad K F The coadtn-sate dtowed a intmm coaceatratioa ratio of aboat 10 rentiwe to dar salt Tha resak tajatsts a pinablc method for coaccatrafiag aad collectiag tntiam -a aa MSMl Related work showed that NaBF0H dnnohed ia ^ltobal sah uadergoes a reactwn that redaccs the OH ~ coaceatratioa m the salt prodacmg a mbtde frac-tkm Phyacal aad chemical obstrtalioas were made on the sysem VaF-NaBF-BjO at 400 lo oOtfC Work with compoaikms typical of ibe usual coulaat salt (oxide coaceatratioas up to 1000 ppm| showed that at least two oxygea-ooataaaag species are present One species n N a raquo F raquo 0 the other has not yet been bulldenirfied
Slddtes were continued o determine the extent lo which borides were formed in Hbstetoy N and btcoael 600 by reaction with NaBFlaquo-NaF at 640degC Data obshytained thus far indicate some formation of chromium and nickel borides however after four months of exshyposure of the alloy samples lo sal the boride concentra lion on the metal surfaces did not exceed 500 ppm in
I X
Haste X and 1000 pom m hwoaci MM) The tcvdh jhraquo dtuwei that A n mdash i n n these laquobullgtbullgtgt was setec-incigt gtraquodued by rhe salt
IkMb thrv period I I ~ ratio were oMMoted by laquogt4taaMneirv lechnnnsrgt in imu rhetmai-cunvecSoa loop and ltAC oiced-circgtdaraquooa loop Subie redox mo dnom H4MIHK bullbull exist m tbmnal-convrctiou loops U A ) 2V the I I ut9raquo raquo approximately T A IO ani respectively In forced-cunvectampn wop H I - gt she I I rlaquoraquolaquo n about copy Vraquo meinpfs feme et Keen ante laquobullgt reoxuJur the I i fhe melt by the addition ot mchet tiuundelaquolaquo some other oxidant
The results rora the fast series of tntnuu ldditmn experiments at the ( raquo u b n - U i Tcdmulugy Facem ltholaquo (wraquo ten tattle mimm exist m the off-gas m the ctesnental state the bwtli of tbe tntruei ltvwi at i iuai-huved laquo water-Mi Ale K m h appears thai about W of the uuecttd inmm experienced tvawticanf holdup raquo thr salt -and was eveutualy remmed m the system ott-
It was observed that the Fe - Fe electrode reacshytion n molten LraquoF-leF-ThFlaquo lt~2-l6-l2 mok i ckfseH approximates the soluble product case at a guid electrode the inwduMc product case at pyroiytic graphshyite and- deptwdmg on the temperature both soluble and insoluble product cases at an indium ekxtrode
Yoffarmarirw measurement were node m muMen liF-nVF -fhF 4 toSowute jddrtiuru tit Li Te is an effort to identify soluble etevitoactive lehurium species re the melt No soitammetnc evidence of such comshypounds was ohtaated These observations were m general agreement with cherracal analysis that indicated lt5 ppm Tern the salt
fAKfi MATEMALSKVF4j0PMtIVT
u Dtncfupmvnl bull bull MMuinJ lunumvy 3
Work raquo parfnHy complete on the molten-salt test facrlrty to he used mostly for mechanical property testshying Much lt (he test equipment is oprralmn
Alt products except the seamless tubing of the V-Ti modified HasteHoy N were received The first heat weighed lOjOOO Ih and had a fairty narrow working lem-prrature range- The second heat weighed WOO lb and had a wider winking temperature range Seamless lubing is being fabricated by two venders WeMahility studies
on these two beats showed bat their urldnsg d u n e lettstacs were euuwahm to those ut standard Hatfefoy V and thai extstmg wetdng procedures ut standard HaMcwoy could he used fur the y Ti Audited
The mechanical properties of HasteBoy gt inuiiaed wwh ifUnMtm nwhrum aad aiunuMun were evahaied m the undated and uwrradnted MB These piupertjcs were umd to estunate tfae mdwudwd and courtuntd wOBceMtauans of Manwani muhwun and ahnuuHnn reouwed laquou produce bntrte mienueuBK phases The tomnuuu ot brstrk phases m the aloy n i t mdash n muwuni was enhanced by an apphed stxss
SpeciBMns ot modihed HnseSoy were exposed to idlunuw from several dMterewi sources Tbe partial pressure tH tewynum above CrTelaquo at TOO C sMtm reasoatfjty dose to that anttcaujied tor MSMb Metal-lugraphic e-umnitiua o tbe exposed specuuens aite strauwnt revealed iblaquo aftoss coniauung OS to I Nb were resttfant to neTgnnular craefcrng by teiurrum
Further aaatysn ot the data lrlaquown TeGen-l showed that most ot the tdunum m each fuel p s was coircen-tafed on the tube wall The concentration bullraquo the salt was I ppm gtrr less The salt bssbcen preparew igtit gtugtng the fuel pur m TeGen-r and- and the puu tor Telaquoelaquo-- base been assembled tlte tuhng
t ipenments were contused laquobull-gt evaluate graphite as a matenal tor fuel prlaquolaquocrsssng apphcaimus The peneira-tmn ot graphite by buRtuth-utbimn suiutnms was found tigt increase with mcreasmg lithium concentration of the stdutKm and pore diameter of the graphite Decreasing the pore dBrneter or the graohae by pitch impregnation decreased the average depth of penetration However because fhe structure of the graphite was sarobie greaier-fhan-average penetration occurred m reginns bullraquo low density
A thermal-convection loop construcied 01 irkdyb-denum conumed ATJ graphite specimens in hot- and cold-let reports and circulated Bt 24 wt bullbull 141 at t Li for WOO hr at 700 C maximum temperature with a temperature differential of I00degC Very large wetghr mcrextes tJO to tgtT~ cccurted in ail ot the graphite samples primarily as a result of bhmuth intrusion into the open piMouty ot fhe graphite Disamclar-metal mass transfer bet weep molybdenum and graphite was also noted These results and previous capsule test results suggest that fhe presence of mofyhdenum enhances intrusion of bifrnuth-lithium solutions into graphite Thin carbon layers were noted on the molybdenum
X
PART 4 FUEL PROCESSING FOR MOLTEN-SALT REACTORS
8 EsgMecfMg Dcvdopraest of Piocessiwg Operations
Addition of the salt and bismuth solutions to the process vessels in metal transfer experiment MTE-3B was completed Two experiments were performed to measure the removal rate and overall mass transfer olaquofficients of neodymium In the first run about 13 of the neodymium originally added to the fuel salt (72-16-12 mole UF-BeF2-ThF4) in the fuel-salt resershyvoir was removed durine the 100 hr of continuous operation Overall mass transfer coefficients for neoshydymium across the three salt-bismuth interfaces were lower 1ian predicted by literature correlations but were comparable to results seen in experiment MTE-3
For the first 60 hr of the second experiment which was a repeat of the first experiment the rate of removal of wodymium was similar The second run was termishynated because of unexpected entrainment of the fuel salt into the lithium chloride in the contactor which resulted in depletion of the lithium from the fh-Li solushytion in the stripper and stopped further neodymium transfer
Future experiments in MTE-3B will depend on detershymining the reason for the unexpected entrainment of fluoride salt into the lithium chloride and it will be necessary to remove and replace the lithium chloride that is presently contaminated with fluoride salt
A hydrodynamic run intended to determine the effect of increased agitator speed on the extent of entrainme w OIK phux uw tne other in the salt-bismuth conshytactor was performed No visual evidence of gross enshytrainment was found Analytical results indicate that the bismuth concentration in the fluoride salt phase decreased with increasing agitator speed This unshyexpected result is probably due to sample contaminashytion
Development work continued on an electrochemical technique for measuring electrolyte film mass transfer coefficients in a nondispersing mechanically agitated contactor using an aqueous electrolyte solution and mercury to simulate molten salt and bismuth During this report period experiments with Fe-Fe2 were nude with improved experimental apparatus A stanshydard calomel electrode which enables measurement of the mercury surface potential was obtained Electronic filters were attached to the inputs on the xy plotter to damp out noise in the signal to the plotter Near the end of the report period a potentiostat was obtained which will automate the scan procedure now performed with
the dc power supply Copper iron and gold anodes hjve been tested The gold anode is the most satisfacshytory choice since it does not react with the electrolyte solution By noting that the active anode area in the cell could be decreased with no resulting change in the difshyfusion current it was determined that the mercury cathode rather than the gold anode is polarized Results indicate that the ferric iron is being reduced by some contaminant in the system Further tests with purified mercury and electrolytes in the absence of oxygen indishycate that the contaminant was present in the mercury Analytical results for Fe and Fe1 concentrations in the electrolyte phase are inconsistent with expected results Qualitative results indicate that a buffered quinone-hydroquinone system may be usefid as an altershynate to the Fe-Fe2 system
Installation of autoresbtance heating test AHT-4 in which molten salt will be circulated through an autoresistance-heatelt test vessel in the presence of a frozen-salt fim was completed and operation was begun A conceptual design was made of a continuous fluorinator experimental facility for the demonstration of fluorination in a vessel protected by a frozen-salt film Design was completed and installation was begun on a fluorine disposal system in Building 7503 using a vertical scrubber laquoith a circulating KOH solution Inshystallation was completed of equipment to demonstiate the effectiveness of a frozen-salt film as protection against fluorine corrosion in a molten-salt system
Off-gas streams from the reaction vessels in the fuel reconstitution engineering experiments will be conshytinuously analyzed with Gow-Mac galaquo density detectors To determine whether hydrogen back-diffusion in the cell body will be a problem during the analysis of the HF-Hj mixture from th hydrogenation column the cell was calibrated with NJ-HJ mixtures It was found that when the reference gas flow rate to the cell is suffishyciently high i effect of hydrogen back-diffusion is not seen The second engineering experiment will be conducted in equipment which is either gold plated or gold lined to eliminate or minimize effects resulting from equipment corrosion Several alternatives for gold lining or gold plating are discussed The factors which must be considered in deciding between lining or plating are listed
A design is being prepared to define the scope estishymated design and construction costs method of accomshyplishment and schedules for a proposed Molten-Salt Breeder Reactor Fuel Processing Engineering Center The proposed building will provide space for preparashytion and purification of salt mixtures for engineering experincnts up to the scale required for a 1000-MWfe)
l
MSBR and for laboratories maintenance areas and offices The estimated cost of the facility is SI5000000 authorization will be proposed for FY 1978
PARTS SALT PRODUCTION
9 Prodactioaof Flwnde Salt Mixtures for Research and Development
Activities during the report period fall in three categories (I) salt production (2) facility and equipshy
ment maintenance and modification and (3) peripheral areas that indwb preparation of transfer vessels and assistance to others in equipment cleanup
Salt produced in this period totaling about 600 kg was delivered in more than 30 different containers About one-half of the salt was produced in an 8-in-diam purification vessel and had acceptable purity levels The remaining salt was produced in the 12-in-diam purification vessel during five runs each of which involved about I SO kg of salt
Part 1 MSBR Design and Development JREnge
The overall objective of MSBR design and developshyment activities is to evolve a conceptual design for an MSBR with adequately demonstrated performance safety and economic characteristics that will make it attractive for commercial power generation and to deshyvelop the associated reactor and safety technology reshyquired for the detailed design construction and operashytion of such a system Since it is likely that commercial systems will be preceded by one or more intermediate-scale test and demonstration reactors these activities include the conceptual design and technology developshyment associated with the intermediate systems
Although no system design work is in progress the ORNL reference conceptual design is being used as a basis to further evaluate the technical characteristics and performance of large molten-salt systems Calculashytions are being made to characterize the behavior nd distribution of tritium in a large system and to identify potential methods for limiting tritium release to the environment These analytic studies are closely correshylated with the experimental work in engineering-scae facilities Studies were started in this reporiing period to reexamine the expected behavior of xenon in an MSBR This work will ultimately use information from experiments in the Gas-Systems Technology Facilitiy (GSTF) to further refine l 5Xe-poisoning projections and to help define the requirements for MSBR core graphite
I Molfen-Salt Reactor Program Staff Conceptual Design Study of a Single-Fluid Molten-Salt Breeder Reactor ORNL-4541 (June 1971)
Additional core neutronics calculations are being made for the reference MSBR using widely accepted evaluated nuclear data and a two-dimensional computashytional model These calculations will provide updated estimates of the nuclear performance as well as add -tional information on core characteristics Analogous methods and data are employed to provide support for in-reactor irradiation work
The GSTF is an engineering-scale loop to be used in the development of gas injection and gas stripping techshynology for molten-salt systems and for the study of xenon and tritium behavior and heat transfer in MSBR fuel salt The faciiitiy is being operated with water to measure loop and pump characteristics that will be reshyquired for the performance and analysis of developshymental tests with fuel salt
The Coolant-Salt Technology Facility is being opershyated routinely to study processes involving the MSBR reference-design coolant salt NaBF4-NaF eutectic Tests are in progress to evaluate the distribution and behavior of tritium in this system
Candidate MSBR structural materials are exposed to fuel sail at reference-design temperatures and temperashyture differences (704degC maximum nd i 39 aC lt17) and representative salt velocities in forced-convection loops to evaluate corrosion effects under various chemical conditions These operations which are principally in support of the materials development effort also proshyvide experience in the operation of molten-salt systems and data on the physical and chemical characteristics of the salt One loop MSR-FCL-2b which is made of standard Hastelloy N is in routine operation two others to be made of titanium-modified Hastelloy N are under construction
1
m BLANK PAGE
L Systems JR
11 TRITIUM BEHAVIOR IN MOLTEN-SALT SYSTEMS
Studies to elucidate the behavior of tritium in large molten-salt systems were continued in this reporting period Additional calculations were made for the IOOO-MW(egt reference-design MSBR to examine the effects that an oxide film on metal surfaces might have on the distribution of tritium Analysis of the informashytion being generated by the tritium addition experishyments in the Coolant-Salt Technology Facility (CSTF) was begun As additional data and results are developed they will be incorporated into the MSBR studies
I l l MSBRCakvbtioas
G T Mays
Calculations were performed to examine the potential effects on tritium transport to the steam system caused by the formation of oxide films on the steam side of the tubes in the steam raising equipment of an MSBR Th rate of diffusion of hydrogen (tritium) through metal oxides typically is proportional to the firs power of the hydrogen partial pressure in the gas phase as opposed to the i power for diffusion through metals (i-e the diffusion process is molecular rather than atomic) In addition at moderate hydrogen partial pressures the permeabiiity coefficients of the oxides may be as low or lower than those of pure metals Thus at the very low hydrogen partial pressures that would be expected in an MSBR oxide films could offer substantial resistance to hydrogen (tritium) permeation However the efficiency of such films would be limited by the degree of metal surface coverage that could be established and mainshytained during operation of the system
The computational model1 for studying tritium behavior at steady state provides for variation of the metal permeability coefficients of the steam-system tubes but assumes that diffusion through the tube walls varies only with the A power of hydrogen partial presshysure Variations in metal permeability were considered in previously reported results However the model also includes the effect of a mass transfer coefficient for tritium transport through a salt film inside the tubes Since transport through the salt film depends upon the first power of tritium concentration (or partial presshysure) this value was used to estimate the effects of oxide films Effective mass transfer coefficients were
Analysts
computed which included the resistances of the oxide films as well as those of the salt films1
Tritium distribution calculations were made for a variety of situations in which it was assumed that the effective permeabilities of the oxide coatings in the steam system were I 10 10~2and 10~3 times those of the bare metal at a hydrogen partial pressure of I torr (130 Pa) These results were compared with cases without oxide coatings in which the permeabilities of the bare metal were reduced by factors of 110 I0 2 and I0 3 The comparisons were made at three values of the UUgt ratio (10 2 10 and 0 4 ) and in all cases sorption of hydrogen or HF on core graphite was asshysumed to be negligible
The results (Table il) indicate that a low-permeability oxide coating would be more effective than a low permeability in the metal itself for limiting tritium transport to the steam system When an oxide film resistance equal to that of the metal was added the rate of tritium transport to the steam system was apshyproximately halved as would be expected (The total resistance to tritium transport was not doubled because of the contribution from the salt film) The results with a factor of 10 reduction in a steam-tube permeability due to oxide formation indicate that tritium transport to the steam system could be limited to the design objective of 2 Ciday However it may be unreasonable to expect to obtain and maintain oxide films of this quality in an operating system
Additional calculations were performed to investigate the effect of reduced permeability of the primary and secondary loop walls through the formation of oxide coatings These coatings can be expected to form in a manner similar to those expected on the steam equipshyment For a given steam-tube permeability reducing the permeabilities of the loop walls would be expected to increase the amount of tritium transported to the steam system With the reduced loop-wall permeabilities less
1 R B Brig A Method for Ctlculalmr thr Steady Sute Distribution of Tritium in a Molten-Salt Bre jet Reactor Kant ORNL-TM-4804 raquoApril 197)
2 G T May in MSR fmgram Semiamtii Progr Rep Feh 2 1975 ORNL-5W7 pp3 12
3 Although ihri calculalional approach assume thai the oxide film i located inside the tubes rather than outside it can be shown that for given oxide and metal permeaMifie this irrangement slightly overestimate the rate of hydrogen permeashytion through the wall
3
TaMe t l Effect of oxide Wmdash on uitmm i todeamtrttmatm MSUtlaquo
Rjti of oxrior raquolaquolaquo laquobull H inlw ltlaquo meial permnbiliiy Imdash 1 tieaw iytteraquo lOday I io nominal metal ratio 0 i d film Redaced meial
prmKabriiiy mvae tlaquobetr prrambibiy4
1 I 0 811 142$ 1 10 J 656 1169 1 10 115 203
10 10= 173 1351 10 bull 10 138 114 10 bull 10 23 198
10 ltf 19 662 10 I 0 J 16 575 10 10 3 142
10 gt w 2 93 10 10 15 84 10 10 lt 31
No wrption of H or HF on core paphtte At a hydropen partial prewurc of I ion
rWith nomnul meul permeability ^No oxide film
tritium would permeate through the loop walk into the primary and secondary system containments eliminashyting a potential sink for tritium A higher tritium conshycentration for partial pressure) in the secondary system would result creating an increased driving force for tritium transport to the steam system
The result of the calculations did indicate that with out the presence of a chemical getter in the secondary coolant more tritium was transported to the steam system when the primary- and secondary-loop wall pershymeabilities were reduced than in the same cases with reference permeabilities for loop wads However more importantly for those cases where tritium transport to the steam system had been reduced to the design-timi abjective of 2 Ciday through chemical additions of H HF or a chemical getter results showed essentially no increase over the 2-Gday rate Thus it appears that reduced loop-wall permeability hat little effect on tritshyium transport for cases where a tritium exchange mateshyrial is present in the secondary coolant
1 1 9 f^^a^af ^dgt T^haMwaflV frMsawv
J R fcneH G T Mays
A 1000-MWe) MSBR is expected lo generate about 2420 Ci of tritium per full-power day Calculations showed4 that unless a major fraction of this tritium
were converted to a chemical form less mobde than elemental HT the rate of migration of tritium through the metal walk of heat exchange surfaces to the steam system could be unacceptaMy high The purpose of the tritium addition experiments in the CSTF is to simulate the general conditions in the MSBR coolant-salt system to determine the extent to which tritium can be held up in the NaBFlaquo-NaF salt There is evidence that hydrogen-containing compounds in the salt may retain significant amounts of tritium
In the experiments the first two in a planned series tritiated hydrogen was diffused into the circulating salt through the walls of a hollow HasteUoy N tube The tritium could accamuiaie in the salt pas into the off-gas system or permeate through the metal walk of the loop to the ventilated loop enclosure Tritium concenshytrations were monitored in the salt and in the loop off-gas In the firlaquo =o experiments 85 and 97 mCi of tritium diffused through the HasteHoy N injection tube For a detailed description of the experimental condishytions see Sect 22
The computer program5 for calculating the expected tritium distribution in a 1000-MW(e) MSBR was modishyfied to describe the CSTF and was used to calculate potential tritium distributions for the experiments under the following assumptions
1 steady-state conditions 2 only dissolution of elemental tritium (hydrogen) in
the salt with no chemicai reaction witn the salt or any of its components
3 all transport through metal walk varies as the power of hydrogen partial pressure
Calculations were made for addition rates o( tritiated hydrogen equivalent to those achieved in the CSTF exshyperiments using assumed loop-wail permeabilities rangshying from the value expected for bare metal to 10 of that value The results (Table 12) show a significant effect of loop wall permeabiity on the fraction of the added material that could escape through the wafts This table also shows the calculated steady-state concentrashytions of elemental tritium in the salt (nCig) and in the off-gas (pCicm) in the same units that are being wed in reporting experimentally observed conjurations Abo shown are the inventories of elemental tritium in the loop walk that would be associated with the calcushylated transport rates through the wafts Since these cal-
4 G T Mar- m MSB fhjpmm Semhwrnu Prop Hep Feb raquo I97S ORNL-5047 pp J 12
i Hraquo bullltbull ami C W N M j r A Method ft e CtkuUting Ihe Sternly Sime DtttrHmitut of Tritium m t Molten Saft Krrrdrr Kemcior Uml 0RNLTM-UO4 (April 19751
Table 12 Calculated rieady-Male tritium diitrrbuliorw InCSTF foe experimental addition rale
Additi on rate Loop wall Tt ilia ted permeability mixture (fraction of hydrogen Tritium bare-metal Kmraquohigt tmCihr) value)
3 1 79 1 10 10 bull 10 bull
3 3 C 93 io-laquo 10 bull 10raquo
Time to reach 8Sf of steady-
state conditions (hrl
Fraction of addition rale which permeate
loop w-y (it
elemental tril removal in oil
turn r1Hraquo
Klvntental tritium Time to reach
8Sf of steady-state conditions
(hrl
Fraction of addition rale which permeate
loop w-y (it
Iraction of addition rate removed
CD Concentration
tpCicmi
concent ration in tlaquolt traquocigi
03 994 06 400 13 95 771 229 I5IKMI 50
38 149 851 55000 200 42 16 984 64000 2211
03 994 06 5(HI 17 103 7$-raquo 243 I90IJ0 (gt4 37 143 HS7 fi7000 230 42 I S 9S5 77tMM 26tl
Irtiium inventory
in metal walk Kti
01 oK 16 17
013 10 19 20
Sail and oil-gas concentrations only longer times required for steady-slate permeation through loop walls
0I tritium in hydrogen
01 I l tritium in hydrogen
t
s
oriatmas represeai steady-state coadmoiaad the nt-naa additioa experaaeats iavolwr t raaskats it a asefal to cuaader the taae renaaed to reach the steady state At high loop-wal penaeabihiies the coaceatratioas of ekaMRtal bullrtraai m the salt aad off-gas are low aad lead to -each steady vataes qakfcry for die additioa rales (see Table 12)- Soaiewhai toager u
aied arith lower assaned loop-wal ptrmdashnbiam hi al cases iidinaiiialjr I n a y times are niaawd to reach steady-stale rates of tiitiaai release throa|h the loop walls However this has little effect oa the triturate steady-stole levels ia the sail aad off-gas
Figures II aad 12 show the resatts of intiwm cua-ceairatioa raeasareaMau v the salt aad off-gas from
are reqaired to reach the higher coaceatratiaas assoo- the CSTF dariag the first aad secoad irilian addition
tn a m - M B laquo raquo
lO _ I 1 - bull ~~l 1 1 1 1 1 1 1 ^ 5 mdash
O SALT llaquoC | )
bull 0raquoT-laquoAS WATER SOLUBLE t$CiJtmh
A 0FF-euroAS ELEMENTAL (aCiar)
1 Mil
2 bull f
bull0
_ 5 n
poundL_ bull0
_ 5 n
mdash
bull mdash
mdash J jy^TRITIUM ADOlTlON bull mdash
2 2 bull II mdash
oraquo II ^ 10 G c
i s
pound 2 z tal Z I O
bull
0
bull bull
bull
A
bull bull bull
IIIIIJ 1 1
s 0
0 mdash
0 mdash
I 5 s
2
10deg
mdashb bull
e
a
e O
A A
A A
I 5 s
2
10deg A A aaw
i bull bull
s
2
bull -
bull i mdash
in- i 15 17 1raquo 21 23 25 27 29 Si
JULY OATCttTS
Fjj II Ofctcfvclaquo4 tnttvui cottt9MnHtottinCSTF 9ttn I
5
2
5
2 mdash
9
u 2 mdash
H = -S bull o u S 3
2 -
^ raquo mdash
5 h
2
bull0deg
raquo
2
mdash 1 1 1 1 1 1 1 1 = ~ O SALT (laquoCi l mdash bull 0FF-6ASVATCR SOLUBLE fcOA-i5) ^ mdash A OFF-CAS ELEMENTAL (f Citw5) mdash
^mm
a ^^ mdash^ 1 ltlaquo bull raquo I 1 1 4
^^ mdash 1 1
1 4 ~ trade
I bull mdash
bull
bull bull
I bull
I bull mdash I bull mdash
=
U
KITH KM A DOtT ON _
= bull
bull bull
llllll 1 1 1 1 V
bull
mdash
bullr T 0 ^
laquo bull 1 A A ~bull r^^ i S 0 O mdash mdash i S
A A ~~
0 0
e
51 A o = ^v 1 M M
mdash 4 A o-
mdash 1 -
bullbull i
T t If traquo bullraquo OATC MJtutT laquof7raquo
IT laquot 21
bull M M M ti cvrr MM i
7
tests The concentrations reported for the salt represent tritium in a chemically combined form since any eleshymental IfT trapped in the samples would have been reshyleased in preparing them for scintillation counting The tritium in the off-gis was present in two distinctly difshyferent cheriksl fonrr Part of the tritium activity was present in a water-soluble form implying a chemkil compound since HT does not interact significantly with water at room temperature The other form is presumed to be elemental HT since ft was trapped in water after passage of the sample stream through a bed of hot CuO
In all cases the results are presented in Figs 11 and 12 as reported with no corrections for apparent baseshyline concentrations However the results of samples taken before and after each test suggest that nonzero baseline concentrations were present The apparent baseline concentrations for the two experiments were
Itfexpcrineat Mcxatrineat
In uli 17 nCig I nCig In olT-cas elemental I pCicm1 I pOcm In off-jta water oiuMe I pCicm3 50 pCiere
During the tritium addition period for the first experishyment the tritium concentration in the salt (Fig I I open circles) increased almost linearly to a maximum of about 100 nCig and then decreased approximately exponentially over the following 3 to 4 days to its preshytest baseline concentration In the second experiment (Fig 12 open circles) the tritium concentration in the salt reached a maximum of 70 nCig and returned to the baseline concentration about 6 to 7 days later If baseshyline corrections are applied to the salt-sample data the apparent half-lives for tritium removal from the salt for the two experiments ar 92 and 12 hr respectively
If tritium removal from the salt is assumed to be a pure first-order process or combination of such procshyesses and if it is assumed that the processes were also active during the addition period the buildup of the tritium inventory in the salt (for a constant addition rate)should be described by
J M I O - i l l - bull ) X
where
V() tritium inventory in salt at any time I during che addition
A tritium addition rate
A lime constant for the removal process (or proc-esats)
I f several first-order processes were involved bull the intshyrant removal from the salt the time constant X would be the sum of the several individual time constants but the individual values would not be identifiable Substishytution of the actual addition rate into this equation gives the expected tritium inventory in the salt at any lime i f all of the tritium were reacting with the salt Conversely substitution of observed inventory values permits evaluation of the effective addition rate (the rate at which tritium did react with the salt) In either case the results may be expressed as ritium trapping efficiencies with values of 85 and 50 respectively for the two experiments These trapping efficiencies imply that significant quantities of the added material were reacting with and being trapped (at least temponriy) by the salt Data from the second experiment suggest the presence of other mechanisms with significantly longer time constants for removal of tritium from the salt Because of the apparent scatter in the data at longer times the extraction of these time constants was not attempted
The water-soluble tritium in the off-gas during the first experiment (Fig 11 closed circles) did not inshycrease significantly until after the injection was comshypleted and then rose to 1750 pCicm 3 The level then dropped rapidly to about 50 pCicm 3 rose again to about 300 pCicm 1 6S days after the addition and then decreased to lower values In the second experishyment the water-soluble tritium in the off-gas rose rapshyidly during the addition period and reached a maximum value at the end of the addition of 13100 pCicm 3 Abo the ratio of the concentration of water-soluble tritium in the off-gas to that of the elemental form was substantially greater in the second experiment than in the first
Owing to the apparent scatter in the data involving the water-soluble tritium in the off-gas for the first exshyperiment no quantitative evaluation was attempted However in the second test the initial decrease in conshycentration has an apparent half-life of 18 hr but the data again suggest the presence of other time constants An attempt was made to separate the time constants by assuming that the decay curve was made up A two simple first-order exponentials This led to apparent half-km of 9 J and 37 hr for the two processes Numershyical integration of the water-soluble tritium data for the second experiment yielded a total flow of 58 mCi through the off-gas line during the removal period and 75 mCi during the addition period Thus a total of 65 mti or about 65 of the tritium added is accounted for as combined tritium in the off-gas stream during this test Since the concentration of elemental tritium was
8
always less than 001 of the combined tritium concenshytration the presence of any elemental tritium does not significantly affect this observation
The concentration of elemental tritium in the off-gas samples rose during the addition phase of each experishyment 2nd apparently began to decrease as soon as the addition was stopped The maximum concentration in the first test was about 800 pCicm3 and only 40 pCicmJ in the second In both cases the decrease in concentration with time after the addition was too irregular to justify any quantitative evaluation
Although no measure of elemental tritium concentrashytion in the oalt a available a value can be inferred from the concentration in the off-gas by (1) assuming that the elemental tritium in the off-gas samples represents release from the salt and only from the salt and (2) assigning reasonable values to gas stripping parameters in the CSTF pump tank Concentrations of eiementai tritium calculated in this way indicate that the ratios of combinedelemental tritium in the salt were about 50 and 530 in the first and second experiments respecshytively It appears that chemical interactions between the tritium-containitg compound in the off-gas and the new metal of the sample line may have been responsible for the high concentrations of eiementai tritium in he off-gas samples from the first test and that the actual ratio of combinedelemental tritium in the salt may have been higher than 50
The inferred maximum concentration of elemental tritium in the salt during the second experiment is about 013 nCig Extension of the calculated tritium distribution with nominal metal-wall permeability (Table 12) to lower concentrations indicates that at 013 nCig tritium permeation through the loop walls could account for no more than about one-third of the tritium added to the system Since this is close to the amount not accounted for in the off-gas samples it appears that the effective permeability of the loop walls is near that of bare metal
12 XENON BEHAVIOR IN THE MSBR
GTMays
The computer program MSRXEP Woden-tali Rate-tot Xenon Poisoning) describing the X e behavior in the reference-design MSBR was used to perform calculashytions to study the effects of the Knudsen diffusion coefshyficient for xenon in the bulk graphite and graphite coatshying of the reactor core on the X e poison fraction The program has been described previously bull7
Following the fission of the fuel the decay of the mass-135 fission fragments is assumed to follow the decav chain shown below
l l
5 X e (1529 mm)
135 s C i J 135
(659 hr) Ba
(30 X 10 yr) (stable)
This diagram illustrates the half-life of each isotope and the branching ratio of the 3 5 1 decaying to 5 m X e and l 3 5 X e assumed for this study Along with this decay chain the following input data were used
Bubble concentration 44 bubbles per cubic centimeter of salt
Total helium dissolved in salt and present in gas bubshybles 10 X 10 molecm3
Bubble separator efficiency 907
For these conditions the mass transfer correlation in the program gives a bubble mass transfer coefficient of 00166 cmsec which leads to a loop-averaged void fracshytion of 055 with an average bubble diameter of 065 mm The calculated 3 f Xe poison fraction is 00046
The reference Knudsen diffusion coefficients for the bulk graphite and graphite coating associated with the 00046 poison fraction are 238 X 10 and 258 X 10 cm2sec respectively The bulk graphite values were varied from 258 X 10 to 258 X 10 cm1sec assuming no graphite coating was present (Table 13 cases I 3 5 7) to observe the effect on the poison fraction The low-permeability graphite coaling - 028 mm thick was assigned bulk-graphite values for the Knudsen diffusion coefficient and porosity making the coating part of the bulk graphite for calculation purshyposes Under these conditions the porosity of the bulk graphite was held constant at a value about 31 times
bullThe complete units for diffusion coefficient arc (cm ps) (sec bull cm graphite)
6 H A McLain el al in MSR Pmgrmn Semttmu front Rep Aug 31 1972 ORNM832pp If 13
7 H A McLam et at in MSR fmpwm Stmiumu Prop Rep Feb 29 1972 ORNL-47K2 pp |3 16 17
9
Kmfara M i a s m cocflkatat l c raquo p v laquo c -en graphite) CakabKlaquo1 Xe
DOHOB fractna M k f r a p a i K Graphite coati
CakabKlaquo1 Xe DOHOB fractna
1 258 x 10 Socoanag 00153 2 258 x 10 258 x 10 bull O0J52
3 258 x 10 No CiOMg 00140 4 258 x 10 bull 258 x 10 7 00I4S
5 258 x 10 bull Nocoatne 00113 258 x 10 bull 258 x 10 00107
7 258 x 10 No coalBaj 00077 8 258 x to bull 258 x 10 c 00044
M t graphite porosity ralae RKMH COHSUHI in ail cam 31 t met greater than rhe valar for ike graphite coating Refereraquoce valar for Hrfk graphite r Reference laquoalac for graphite coanag forma fraction for reference case
greater than that of the graphite coating In addition the Knudsen diffusion coefficient for the graphite coatshying was varied within the same aforementioned range while the diffusion coefficient of the bulk graphite was held constant at its reference value oi 258 X 10 cm 2sec to observe the effects on the poison fraction (cases 2 4 6 81 The previously stated values involving bubble characteristics and mass transfer were held conshystant throughout this series oi cakulalions
The results (Table I J | indicate that Knudsen diffushysion coefficient for the bulk graphite and graphite coalshying at least as low as the reference values (258 X 10 and 258 X 10 cm 1 sec ie case 8) would be reshyquired to meet the 0005 target value I gtr the X e poison fraction A diffusion coefficient of less than 258 X 10 cm 2sec would be required for the bulk graphshyite with no coaling became of its higher porosity If the permeability of the graphite coating did not yield a difshyfusion coefficient equal to that of the reference value such a coating would have little effect ltgtn xenon poisonshying The penalty for not coaling ihe graphite iraquo about OX)I in xenon poison fraction or 001 in breeding ratio if no attempt is nude to decrease the permeability or porosity of ihe base material
It may be noted in case 3 that a slight reduction in the Knudsen diffusion coefficient for ihe bulk graphite is
more effective in reducing the 5 X e poison fraction than a simitar reduction in the Knudsen diffusion coeffishycient for the graphite coating in case 4 In cases 6 and 8 where the permeability of the coating is very low reshyducing the Knudstn diffusion coefficient for the graphshyite coating affects the 5 X e poison fraction much more strongly
1 3 NEUTRON ANALYSIS
H T Kerr D 1_ Reed E J Allen
The neutronic analysis work during this reporting period has involved several tasks aimed at additional description of the neutronic characteristics of an MSBR and the provision of ncutronics information for the fueled in-reactor irradiation experiments
I JI MSIX Studies
Neutronic analysis studies for the reference-design MSBR are in progress in three areas
1 development of a two-dimensional neutronic comshyputational model of the MSBR using the computer code VENTURE and reestablishing the operabiliiy of a reactor optimization code (RODI
2 updating the neutron cross-section data bast used by various computer programs
3 calculation of the rate at which helium wii be proshyduced in the reactor vessel of the MSBR
A neutronic computational model o( Ihe MSBR using the computer code VENshyTURE is being developed VENTURE is a multishydimensional multigroup neutron diffusion computer code The MSBR model will have nine neutron energy groups and the ir-z geometry shown in Fig I J The various zones in the model allow for different core comshypositions and cress-section sets In addition to providing a check oi the design studies made with the ROD code using one-dimensional calculations this model will pershymit explicit evaluation of the nuclear reactivity effects associated with localized core periurbatiuii ltch as limited core voiding Previously such effects were conshyservatively estimated from calculations for an infinite medium of salt and graphite
bullhr pneffcv tuuHaniial reducifcMt in da Kmudm aWuaioa owflfcieat probatory wouhl be accompjaml by reduced po-roaiy
I T B r- ter 0 R Voady and G W ( unnmfham III irTlKf A CoaV mock for Sotriig Htipaup Stummk-ProNtwt Applying the Finite-Difference DiffmkmPieorv Appnaimntkm to Seutron Trmnpprt ORNL-SOamp2 tOvtohet 175raquo
9 II r Ramnann el al HOD A Sudew (md Fuel Cycle ImfSt-Mi Code for CmuUlmtFuel Rewclon ORNL-TM-3JS9
l September I 711
10
79-m7S
-a r
a-7
PERCENT THICKNESS 1 cm) ZONE NO FUEL SALT RADIAL AXIAL
1 CONTROL ROOS 172 2195 2 CORE )A 132 32 a 2195 3 CORE I A 132 500 2195 4 CORE I B 132 1195 2195 5 CORE n A ANO B 370 381 254 bull 9lR)^bV ^ W ^ ^ V v 1000 51 51 7 GRAPHITE REFL 10 7S2 aio bull SALT ANNULUS 1000 oa oa 9 REACTOR VESSEL 51 51
Fk 1 J Tw MMMH^OMI coMf bulltMtoMiMoMorNsm
11
ROD is a computer prccram for nuclear and fuel-cycle analyses of circulating-fuel reactors It consists essenshytially of a neutronks subprogram an equuibrium-conceniration subprogram and an optimization subproshygram Variables uch as breeding ratio fuel composition etc can be optimized with respect to cost
The operational status of the ROD code has been reshyestablished by running a telaquo case for the reference-design IOOO-MW(e) MSBR using the old cross-section data previously generated for the MSR program The test case will be rerun using the ENDFB-IV cross secshytions and any significant differences will be evaluated and reported
Generation of bullposted cross section data The necesshysary descriptive information for the neutronic model for use in the computer code VENTURE has been colshylected and the most recent ENDF1 cross-section data are needed (The neutron cross-section data used for MSBR analysis were originally derived from the GAM-H and ENDFB-I libraries with some ORNL modificashytions1 and no recent updates have been made) The new cross-section data are being obtained exclusively from the ENDFB-IV data Tiles using the AMPX processing system This effort will provide evaluated cross-section data and neutron energy spectra for typical regions of an MSBR and will serve as the data base for subsequent MSBR nuclear analyses The steps involved in this process are
1 Calculate 123-neutron-energy-group cross sections from the ENDFB-IV library The ENDF point data for 39 nuclides are weighted over an assumed energy spectrum to derive mulfigroup cross sections Thermal scattering cross sections are treated at 300 600900 and 1200 K for each nudide
2 Determine contributions to the multgroup cross secshytions from resolved resonances resonance self-shielding is treated for the various fuel configurashytions at 900 K
3 Perform fuel-moderator cell calculations for four geometries to adjust the cross sections for the flux depressions in regions having a high concentration of fuel or moderator (ceD homogenization calculashytions)
10 ENDFB-IV is ihe Evaluated Nuclear Data File-Vcnion IV and is the national reference set of evaluated cross-section data
11 O L SmithPreparation of 123 Group Matter Ctwt Secshytion Library for MSR Calculation ORNL-TM-4066 (March 1973)
12 N M Crane et al AMPX A Modular Code System for Generating Coupled Muttipoup Neutron-Gamma Ubraries from ENDFIB ORNL-TM-3706 J1974)
4 Perform a one-dunemional neutron transport calcushylation of the MSBR core to determine 123-group spectra and collapse the 123-group cross-section set to nine groups for each of the various zones in the model
5 Reorder the nine-group set from nudide ordering to group ordering the cross sections are then ready for use in VENTURE and ROD
The initial processing step is capable of treating nuclides in groups of from 1 to 3 depending upon the amount of data in the ENDFB-IV file for each nuclide This step is now complete for aD the nuclides of interest except 2 T h
Heauaa production bull reactor vessel The helium proshyduction in the reactor vessel for the present reference design and possible alternate designs will be estimated in conjunction with the neutronic modeling of the MSBR (Neutron energy spectra and flux magnitudes in the reactor vessel as obtained from the neutronic modd provide the bass for calculating helium production rates)
Helium is produced in nickel-base alloys primarily from these reactions
raquoNi raquo gt raquoNi raquo gt 5 Fe + 4 He
N i ^ L _ raquo F e laquo H e
degNi gt i 7 F e r 4 H e
The sNi(njt)and the degNi(ija) reactions are induced only by high-energy neutrons whereas the 5Ni(n7raquo and 5 Ni(laquoa) reactions are induced primarily by low-energy neutrons In highly thermalized neutron energy spectra as in the MSBR vessd the two-step reaction 5Ni(n7) $Ni(ffa) is the principal source of helium The 5 Ni cross sections are not wdl known but differshyential measurements are being made by ENDF particishypants1 Abo hdium analyses are available from several irradiated nickd specimens and effective integral cross sections wii be derived from these data for comparisons with the measured cross sections
At presen some cross-section information is available for the NHHJO) reaction Values for the 2200-msec (ix 00253-eV) cross section have been reported as 137 barns 4 and 18 barns It has also been reshyported1 3 that a large resonance occurs at 2039 cV with a total width V of 139 eV From this information a preliminary estimate of the shape and magnitude oi the
13 F C ferry Report to the US Sutiear Data Committee ORNL-TM-4SS5 (April 1975)
14 H M Eibnd el al Hud Sri poundltty 5) I I January 1974
12
cross section can be deduced and 123-group cross secshytions generated
From the Breit-Wigner one-level formula
where
A = constant A = neutron energy
tr = resonance energy (2039 cV) = total width (139 eV)
The constant K can be determined from the value of the cross section at 00253 eV which for this study is assumed to be either 137 or 18 hams Energy-dependent cross sections can be generated and the helium production can then be estimated with te folshylowing equation
-V H eltraquolraquoraquoraquoilaquoraquoJ - bull bull )
X 1 - e x p ( - o e 0 1 o
- [I exp ( -OJ IDI OJ I
where o ( = (17) cross section of s Ni Oj = absorption cross section of s N i Oj = (na) cross section of N i A1 - initial s N i concentration
9 = neutron flux = time
V|| e(0 = helium concentration at time t
IJ2 Analysis of TeGenE-r-raquoiments
Fission rates and tellurium production rates for the fuel pins in the TeCen-l irradiation experiment were reported in the preceding MSR semiannual report The fission rates were estimated by a flux mapping experiment direct flux monitoring of the TeGen-l capshysule and computations analyses The tellurium concenshytrations in the fuel pins were calculated from these fisshysion rates but no estimates for the accuracy of the calculated tellurium concentrations were given in the report
The accuracy of the 2 3 U fission product yield data 1 6 leads to an estimated uncertainty for the yield of tellurium in the TeGen-l capsule of about 135 Assuming that the uncertainty in the estimated fission rates is plusmn15 the uncertainly in the reported tellurium concentrations is about 20
The TeGen-2 experimental capsule is scheduled to be inserted nto the ORR for irradiation in October I97S Flux monitors will be loaded into the capsule prior to the capsules insertion into the ORR After the TeGen-2 capsule is removed from the reactor the monitors will be recovered and their induced activities measured to develop estimates of the tellurium production rates for TeGen-2
14 HIGH-TEMPERATURE DESIGN METHODS
GTYahr
Thermal ratchetttng and creep-fatigue damage are important considerations in the structural design of high-temperature reactor systems Simplified analytical methods in ASME Code Case IS92 (ref 17) and RDT Standard F9-4T (ref 18) permit the assessment of ratchetting and creep-fatigue damage on the basis of elastic-analysis results provided 1 number of restrictive conditions are met Otherwise detailed inelastic analyshyses which are usually quite expensive for the conditions where they are currently necessary are required to show that code requirements are iet Analytical investishygations to extend the range over which simplified ratchshyetting and creep-fatigue rules may be used to show compliance with code requirements are being performed under the ORNL High-Temperature Structural Design Program which is supported in part by the MSRP Modeling procedures for applying the simplified ratchet-ting rules to geometries and loadings prototypic of those encountered in LMFBR component designs are to be identified Then trie conservative applicability of these ratcnetting rules and procedures and of elastic creep-fatigue rules will be demonstrated and placed on a reasonably sound and defensible engineering basis Finally an assessment will be made of the applicability of the simplified design methods to Hasteiloy N under MSBK design conditions and the importance of thermal ratchetling in an MSBR will be determined
S II T Kerr and F J Allen in MSR Program Semiannu Pnrfr Rep Feb A 1975 ORNL-5047pp M 15
16 M F Meek and B F Rider Compilation of Fission Product Yields Vallecilos Suclear Onter 1974 General Elec-ric Company NFDO-I2I54-I (January 26 1974)
17 Code Caw 1592 Interpretations of ASMF Boiler and Prejre Vessel Ctde American Society ltbull( Mechanical Fni-neerv New York 1974
18 KDT Standard F9-4T Requirements flt Construction of Suclear System Components at Elevated Temperatures (Suppleshyment to ASMF Code Cases I$92 1593 1594 1595 and I5VA) September 1974
13
The detailed plans for achieving the stated objectives were given in a previous progress report The basic approach is to perform a relatively small number of carefully planned and coordinated rigorous dastic-plastic-creep ratchetting-type analyses of the geometries illustrated in Fig 14 Each geometry is subjected to the axial bending thermal transient and pressure loadings described in Table 131 of ref 19 Structural problems I and 2 are being analyzed at ORNL using the PLACRE computer program 2 0 while problems 3 and 4 are being analyzed by Atomics International and Comshybustion Engineering respectively using the MARC comshyputer program1 Each inelastic analysis will include a complete code evaluation for accumulated strains and creep-fatigue damage Also ssociated with each inshy
elastic analysis are a number of elastic analyses to proshyvide the input parameters required to apply the various simplified ratchetting rules and procedures and elastic creep-fatigue noes The progress to date on these studies is discussed below
Both Al and CE have encountered difficulties in their three-dimensional inelastic analyses Although consider-
19 J M Comm and G T Yabr in MSR Program Semmtmu Progr Rep Feb 28 1975 ORNL-5047 pp 15-22
20 W K Saitory Fiirte Element Pnfnm Documentashytion High-Tempertnre Sintctmwl DrsnM Methods for LMFBR Components Quart Prop Rep Dec SI 1971 ORNL-TM-3736 p 66
21 MARC-CDC developed by MARC Analysis Research Corporation Providence Rl
-YV^ - NOTOCD CTLMMCM SHELLS TYPE 3 N0ZZLE-1D-9PHQMN
OftNl OWC 75 76S
SMELL
JUNCTION OETAS (TYPES 341
76i0 X ilaquo75 WML
TYPE 2- cnjomctL awns
Q-omdash -T-QlaquoO -Q0
) AT AT I (bull) STEPPED MMLTHKKNESS (k) UNFClaquoM WILL WTH
OFFERENTUL MTOCTTNG
TYPE 4- nomz-m-crurvmcM SHELL flHXMLET NOZZLE)
1 6 0 0 X0375 WALL
-TS IO X 1675 WALL
(O IMFODM VMU MTH (ABULT-M CYUNOEP AXIAL TEMPERATl J VWaATCN
Fij 14 Slnicturai crmfiguraiinns used in the analytical invatqplion of the applicability of simplified nlchetling and crrcp-faligiie rule
14
able effort has gone into developing fmite-elemeni models that are of a size that can be accommodated on presrnt-day computers and into improving the MARC computer program the large 3-D inelastic analyses are proving considerably more expensive to run than had been expected
The experience at AI and CE indicates the importance of developing amplified methods of analysis Three-dimensional inelastic analysis of many realistic comshyponent geometries is too expensive and time consuming at present to be used routinely Although developments in computers and stress analysis programs may bring the cost down in the future it is desirable meanwhile to mminuze die number of inelastic analyses that must be done
141 GrcutarCyundricai Shells
Nine cases of circular cylindrical shells luve been proshyposed for bulllaquo present study Two of the cases involve notched shells The other seven cases involve axial variashytions in temperature pressure andor wall thickness or a bunt-in wall All nine cases were to be analyzed using the ORNL in-house finite-element program PLACRE
A ten-cyde inelastic analysis and a one-cycle elastic analyras have now been completed for all nine cases Both thr inelastic and the elastic results for all nine cases have been completely poKprocessed
Because of modifications to the creep-fatigue damage rules presently under study by the ASME Boiler and Pressure Vessel Code Working Group on CreepFatigue it may be necessary to modify the ORNL postprocessor and repeal some of the postprocessing to keep the present study up to date
142 Nozzle-to-Spherical Sfcenf
After some difficulties the MARC computer code a operational on the IBM computer at the Rockwell Intershynational Western Computing Center and check cases have demonstrated that this code will perform satisfacshytorily
Considerable effort has gone into developing the finite-element model of the nozzle-to-sphcricai shell An isoparametric three-dimensional 20-node brick eleshyment will be used (o model the entire geometry Beshycause of symmetry about the plane of the applied moment only half of the nozzle-to-spherical shel has to be modeled There are raquoix 30deg-wide dements around
bullWork jlt ORNL by W K Sartory Work raquobull Atomics International by Y S Pn
the half-model There are three elements through the wall at the root section of the nozzle and only one element through the wall in both the nozzle and the sphere away from the intersection region
A series of elastic analyses must be done since this is a thermal stress problem in which temperature varies with time Since the moment applied to the nozzL is the only nonaxtsymmetric load the principle of supershyposition will be used to reduce the cost of the elastic analyses A series of axisymmetrk analyses were done to determine the stresses due to the internal pressure and temperature and one three-dimensional analysis was done to determine the stresses due to the moment applied to the nozzle The stresses from the three-dimensional analysis will be added to the stresses from the axisymmetric analyses to obtain the total elastic stresses
The axisymmetric model in the elastic analyses was used to determine what maximum thermal load increshyment may be employed without having to do an excesshysive number of iterations during each increment On this basis the first ryele of the three-dimensional inelastic analysis was divided into 32 increments The first three increments of the three-dimensional inelastic analysis have been completed The computer cost for these three increments was higher than anticipated Efforts wiQ be made to find some way to reduce the cost to an acceptshyable level
14J Nozzte-toCyindeT Intersection
The original concept for the inelastic ratchet ting-type analysis of the nozzle-to-cylinder intersection was to perform two separate analyses (I) a thin-shell analysis of the whole structure ami (2) a detailed three-dimensional solid analysis of the intersection only Disshyplacements and forces to be applied at the boundaries of the three-dimensional solid model of the intersection were to be determined from the shell model at the end of each loading increment The total computer time of the two analyses would be less than that required for the solution of the problem using one model of the complete nozzle-to-cylinder intersection with suffishyciently small elements in the intersection region Howshyever the transfer of the forces and deflections from the shell analysis to the three-dimensional solid analysis was found to be more difficult than anticipated Because the shell element and solid element have differtit displaceshyment functions a special constraint must be imposed on the shell elements at the boundaries of the three-dimensional solid model to assure compatibility This
bullWork at Combustion Engineering by R S Barsoum
15
stiffens the intersection in the shell model When runshyning the initial elastic analyses it was found that small changes in the displacement boundary conditions applied to the solid model would produce large changes in the results of the analysis- From a pragmatic viewshypoint the biggest difficulty with the two-model method is assuring that the correct data are transferred from the shell analysis to the solid analysis at every increment in loading
Due to the above considerations it was decided to do the analysis by using only one model made up of a combination of a reduced integration shell element and a 20-node solid element which are fully compatible with each other
It was necessary to restructure a large portion of the MARC program to perform the inelastic analysis for the
3-D nvdel of the nozzle-to-cylinder intersection This restructuring made a larger core available for the analyshys t The restructuring involved stripping unnccded porshytions of the program putting common space on low-cost storage and eliminating mesh optimization and its correspondence table
The inelastic analysis of the nozzle-to-cylinder intershysection was started The full pressure and nozzle-moment loadings were imposed on the structure which resulted in stresses less than 0936 of the yield stress at 870 K ( I 00degF) When the first increment of thermal load was applied convergence was not obtained because of an error in the computer program which is being corrected
2 Systems and Components Development R H Guymon
21 GASSYSTEMS TECHNOLOGY FACILITY
RHGugtmon GTMays
After a brief shutdown at the beginning of this repottshying period to modify running clearances in the pan water operation of the Gas-Systems Technology Faculty (GSTF) was resumed on March II 1975 with the bypass loop blanked (Fig 21 gt Considerably larger salt-pump shaft oscmatious were encountered than before the labyrinth clearances were increased1 After obtainshying calibration data for the main-loop variable-flow reshystricts and for the salt pump at low flows the ioor was shut down to install the bypass loop variable-flow re-slrictor Water testing was then resumed on April 14 and continued throughout the period
Data for calibration on the bypass loop variable-flow rcstrictor and for the salt pump were obtained At normal pump speed the head-capacity performance of the installed imprDer was v W below the nominal loop design conditions At the nominal liquid flow rate and pressure drop in the main loop the flow rates from the gas outlets of the bubble separator were satisfactory Although loop cavitation (as indicated by wise level) was reduced by replacing the variable-flow restrictors with orifices the amplitude of the salt-pump shaft oscilshylations was not reduced appreciably Prdirmnary infor-
I R H Gaymoa MJ V R Haadty JUSK ABVW Stmt-mm Anjr Rep Feb 291975 ORKL-507pp 23 25
shows that leakage past the salt-pump shaft labyrinth is higher than desirable and attempts wfti be made to reduce thts
Tests under actual operating conditions with water in the loop indicated that the densitometer war be sttsfac-tory for salt operation IVelinwuary information obshytained fiom saturating the loop water with air and then stripping the air by injecting hehum at the bubble genershyator indicated the need for moniioring the oxygen conshycentration in the off-gas from the bunt salt separator in the off-gas from the salt pump in the loop water and perhaps in the water in the pump tank Dtitkuhies were also encountered with the response lime of the oxygen monitors and with the reprodudbiity of their readings
Data on the salt-pump shaft deflections and oscara-tions obtained during the previous period indicated that the running clearances at the labyrinth (fountain flow area I and at the impeuer hub should be increased to prevent contact of the metal surfaces during operashytion with salt (Fig 22) After increasing the clearances water operation was restarted with the bypass loop Hanked off The shaft oscillations were much larger than they had been previously under similar conditions Turbulence or cavitation as indicated by noise was the apparent cause For more flexibility in (Renting condishytions the bypass-loop variable-flow restrictor was inshystalled Loop parameters were then recorded at many
cwmmo
Flaquoj 21 GB4VMWM Facaw
16
17
n$ J J csrf w raquoNVJgt
coaibinaiiotts of lalt-pump speed and settings of the mam loop and hypass4oop variable-flow lestriciorv
Lug-log plots were nude of pressure drops across various sections of the loop as functions of the flow rates through the segments Ssnce the head loss for a fixed resistance is proportional to a fixed power of the fluid velocity the cams should be straight lines unless the character of the resistance changes due to cavitashytion The pSots indicated that cavitation was occurring in the main loo between the inlet to the nauvloop variable-flow restricior f FE-l02A)and the throat oi the bubble generator at flow rates above 320 gpm (1200 liters mm I with the variable-flow resiriclor set at I in (25 mm I above 470 gpm with the variable-flow reslric-tor at 2 in (100 litersmin at 51 mml above 600 gpm with the variable-flow restricior at 3 in (2300 btersmin at 76 mml and above 630 gpm with the variable-flow resthctor at 4 in (2400 litersmin at 102 mml The data were not sufficiently precise to determine whether cavishytation was also occurring in the bypass loop however noise indicated thai it was
Since the loop turbulence andor cavitation as indishycated by noise and the salt-pump shaft escalations were unacceptable at conditions required by the bubble separator design changes were made in the main-loop and bypass-loop flow restrictions By replacing each vamMe-flow restrictor with two or more orifices in series the loop noise level was decreased but there was
little or no decrease in the aaphtwdr- of the a f t oscd-btions
The amptitaae of the shaft ascafetsoas was plotted as a wactiua of salt pump speed at various operating a laquo -dMMis (Fuj 23| At salt-pump speeds less than about 1600 rpm the oscantioas were reasonably smaM and ai any given speed appeared to be unaffected by (11 flow rates between 450 aad 1 0 ) gpmlt 1700 to 4000 liters n a n M 2 ) salt-pump overpre wares between 5 and iSpsig ( I J X 10 to 2D X 10 Pal ( 3 | type of restneuon (variaafc flow restnetors orifices or a coiahmaiion ot these I or 14) flow roate (through the main loop bypass loop or both) At higher speeds the osdaatioa ampit-twe mcreased rapidly with mcieasts in speed and there was mote scatter in the data making it difficult to evalshyuate improvement in cavitation and effects of other variables However at any given speed above about 1700 rpm mcreasmg the flow rate (between 450 and 1050gpm)caused larger oscanuoas
One puaablf explanation for the increased amplitude of the osculations at higher speeds b thai the shaft is approaching its critical vibration frequency and is theiraquo-fore more sensitive to disturbances such as loop turbushylence or carnation The critical speed of this impeller assembly is 220 rpm in an which would indicate a maximum normal operating speed of 1710 rpru using bullhe normal industrial practice ot operating pumps at less than 75^ of critical speed
If the pump shaft osculations were in fact a conshysequence of operation near the critical speed ot the rotating assembly two obvious alternatives were availshyable to reduce the amplitude of the oscuHaiions
1 further reduction of the loop disturbances to minishymize the driving forces that cause oscillation
2 operation at lower speeds to reduce the osolatorv response to disturbances
The first alternative was rejected because it would have required extensive modification of the loop and it was difficult to guarantee that all sources of such disturbshyances could be reduced to satisfactory levels Design cakidaiiofls showed that the desired flow and head (3800 litersmin at 3 0 3 m or 1000 gpm at 100 f u could be obtained by replacing the present 11 Virt-diam (2ftgtnun) impeter with a l3-tn-dam (330-mail unit and operating it at 1500 rpm A larger impeller is being machined from an available HastcHoy N rough casting Since the larger impeller will be somewhat heavier than the original one it win cause a reduction in the critical speed of the rotating assembly The estimated critical speed with the new impeller is 2000 rpm which makes the operating speed 757 of the critical speed
18
n-va
I
bull
bull 4SO-C4V laquo bull TOTM run
bull bull80-KM9 laquo bull TOTH FLOW bull t
bull bull
bull
bull bull bull bull bull bull
bull bull bull bull m bull m bull
r- i bull gt
bull bull bull bull - bull jr bullbull r laquo bull 1
bull laquooo ooo rsoo i4oo CMO
SALT n w SPCEO t fraquo) lt7oo laquoaoo
Flaquo2J GSTFpanpAtfia
At a few off-design conditions during some of the bter runs the pump shaft deflection records showed random spikes in one direction superimposed on the relatively uniform oscillations described earlier These occurred with higher than normal flow rates in the main loop or at reduced system overpressure Since eidter increasing the overpressure or injecting gas at the bubble generator reduced or eliminated these random oscillashytions it was concluded that they were a consequence of cavitation at the bubble generator Such cavitation and the attendant oscillations are not expected to occur at normal operating conditions
212 Sak-Twnw f i i f i inmdash u DMa and CaKbration of the Variable-Flow Ratricton
The original design of the CSTF provided for varying the salt-pump speed andor changing the variable-flow restrict or settings to obtain different flow rates or presshy
sures needed for future experiments However instrushymentation will not be provided for measuring the bypass-loop flow rate during salt operation and only urn salt pressure measuring devices will be installed I at the salt-pump discharge and at the bubble-separator disshycharge) Also since the salt pump was modified and has a mismatched impeller-volute combination no perforshymance data were available Therefore extra pressure indicators were installed for the water tests and loop pressure profiles were obtained at various pump speeds flow rales and variable-flow restricior settings to evalushyate the pump peiformance
The calibration of the main-loop variaMe-flow restric-tor and of the salt pump at low flow rales was straightshyforward since with the bypass loop blanked off the total pump flow was measured directly by the main-loop vert tun However once the bypass-loop variable-flow restrictor was installed the calibration of it and
19
the pump was complicated Hie main-loop variable-flow restriciof was closed and the bypass-loop variable-flow rest net or was calibrated at low flow laies using the pump calibration curves established before it was inshystalled The mam-loop variable-flow restrictor was then opened to various settings and the pump calibration curves were extended by adding the measured flow through the mam loop to the flow through the bypass loop taken from the bypass-loop variable-flow reslnctor calibration curves Then using these extended head-capaciiy curves for the pump it was possible to extend the calibration curves to higher flows
The pump calibration curves (Fig 241 indicate that at 1770 rpm the pump flow rate wiB be 970 gpm 13700 litersmm) at 100 ft 1305 ml of head The ongnul design called for 500 gpm (1900 litersmmgt through each loop however the bypass flow rate can be reduced to 470 gpm (1800 liters mm) without compromtsng any of the objectives
To determine the main-loop variable-flow restrictor selling for normal operation with a flow rale of 500 gpm in the mam loop plots were made of the pump head vs flow for several settings of the flew restrict or From these a curve was made of pump head at 500 gpm (1900 litersmm) vs settings (Fig 25) A 185-m (47-mm) setting wril give the desired head of 100 ft (305 m) at 500 gpm
m - K B i
lt M M laquolaquo IFC-I02M SCTTWG FOraquo 300 laquo bull Zr-MSS laquo bull C-laquo4AJ
SpoundTTlaquoVS FOM0laquoB ^ Str-MSS vlaquoMFt-laquoolaquoi
si TlaquoK ran 47olaquopraquo
1 2 3 4 VMIASLC FLOS EST^CTO SCTTI
s
FraquoZ5
bull40 bull n-vw
C O shy
CO
l
CO bull
40 1
20 f
o 200 400 M O n o ltooo woo FUMIlaquoOTI
Fit- bullbull Hcai capacity curves for oV GSTF y mdash gt bull
The bypass variable-flow reslnctor settings were detershymined similarly 7 -I found to be 1-85 in (47 mm) at 500 gpm (lltHXgt liters mm) or 170 in (43 mm) at 470 gpm (IK00 liter v mm)
21 J Satt-Pmnp Fountain Flow
The GSTF salt pump is a centrifugal sump pump having an impeller which rotates in a volute section which in turn is located in a pump bowl The clearance between the impeller and the volute assembly at the pump inlet allows leakage from the discharge directly (o the pump suction (see Fig 22) A second bypass flow called the fountain flow escapes through the clearances between the impeller shaft and the volute assembly This bypass stream flows into the pump bowl circulates downward and reenters the main stream at the pump suction Due to the large liquid holdup and large surface area in the pump bowl significant gas-liquid mass transshyfer can occur in the fountain flow stream and herefore its flow rale is important in analyzing mas transfer processes in the loop Since the fountain Pow is not measured directly a method using mass balances on
20
measured gas flows was developed to determute thn flow rale
A lump J-parameter mcjel of the GSTF was used to develop equations Iron which an express lor ike rounfam flow was dented The system model contain two major regions the pump bowl and the primary loop Imnn and bypass segmental cutmstmg ai a fas seciion and a liquid section tach section was assumed to be perfectly mued The three enteral time-dependent equations lor a specific p s m i gas mixture are given m Tabic 21 representing gas mas balances for the pumrbowi gas section the pump-bowl tinwd section and the primary-loop f seciwn Icuculating oidsraquo
These were simplified by applying the folowmg
1 There is no gas carry-under in the pump bowl which implies that Ugt the efficiency for separation of bobshybles from the fountain flow Ut a unity and Ft -Ffi bull | + Afs-gthe bwbWe surface area m the pump howl M I the void fraction in the pump bowl frgtngt and the concentration of gas m the pump bowl (Clt I are nonappbcable or zero
2 Mass transfer equtJibnurn nasts in the primary loop which implies that the mass transfer term - j(C 4 -KRTCi )a zero
3 Steady-stale conditions exist making all time derivashytives zero
4 Ff = 0 since there was no gas purge flow during the experiments
Therefore Eq (3) Table 21 reduces to
FB FfL ltlaquo = 0 Ml Solving f o r +
By adding Eqs (1) and (2) Table 21 and simplifying
FjyenLCgtFfi +1C+FBSCX
FC Ff( rtC1FBSCJ=0 16)
By substituting Eq (5) into Eq (6) Ff may be exshypressed in terms of a quadratic equation
ltC C 2 I F bull KQi Fbdquo FBSKCt C 2 )
FgCt FCtFf
QttlF8SltC C raquo F C | 0 (7gt
Equation (7) is a general solution for the fountain flow which depends upon the gas concentrations in
each ol the three sections of the model It it is assumed that man transfer equAbmm exists at the galaquoltiugtd interlace in the pump jowl the gas conceniciuon in the pump bowl liquid | ( I is relaied to the correspondmg concentration m the pump bowl gas section tCt I raquoy Henrys law If only one gas rs involved (eg heliumK C toNows directly from the pump buwl overpressure Further since mass transfer equuawium was assumed for the primary loop ihe gas ctmcentralion m the kiop liquid (for a smgk gas) ioifews from the loop average pressure and Henry s law Thus the foil am ikm magt be evahsalaquoed from fcq |7raquo using orker known liquid flow rates and measurable gas flow rales into and owl ol the system If no mass transfer is assumed to occm~ at the gas liquid mterface m the pump bowl thr gas conshycentration m the hqmd leaving the pump bowl is the same as thai in the cmtiiug liquid lue O = C I and Eq(7i reduces to
^=IFgCyFCi I ^
Since the rate oi mass transfer m the pump bond is neither minute nor zero Eq I 7 I ni l give a low indftca-tion and Eq (X| laquo i give a high indication of the founshytain flow rate The deviation from the actual fountain flow rate win depend on how much mass transfer actushyally occurs m any experimeni If the loop void fraction is increased (by increasing the gas input rate I the conshytribution of mass transfer across the gas-liquid interface to ihe flow rate of gas laquo-ji of the pump bowl wif be reduced relative to the bubble contribution Therefore a pkn of the calculated iountam flow vs Ihe reciprocal of the gas input rate at several different conditions should give the actual fountain flow rale when extrashypolated to zero (infinite gas flow rate) usmg either Eq (7raquoor(8gt
The preceding equations and approach were used to calculate the fountain How for the GSTF pump Results from ihe plot indicated thai the curves generated were not defined wen enough to provide accurately the reshyquired extrapolations The range of fountain flows at the highest gas input rate at which data were obtained was 100 to 200 gpm (30 to 760 litersmmraquo
Even the lower estimated value for the fountain flow may excessively complicate future mass transfer experishyments so efforts will be made to reduce this flow Since ihe labyrinth clearances cannot be reduced without incurring meial-io-metal contact between the pump shaft and the volute hack vanes will be installed on the lop of ihe impeller lo minimize the differential pressure which drives the fountain flow
Iihfc 21 (iiimiuhaUmimpjallnntfitf timtpulalfcinmiMHof (iVI
KllO til illlll|tkltil |tl pill|K lllllilllis scpHlUil IMIlaquo IfMIKU nl t in nl oil Kii iiivkiilnl ill llnw ill bull limn liiiiiilini bull iliraquoraquonluil |Mgt lt mw ^JVIIHIII pinup linlaquol III yis gt|iui Him lH|iil(lniv inliHir pump Imwl
lltpi l n I lt f lt bull bull bull laquo lt laquo laquo laquo raquo laquo iff
Kllgt ill tlltllllr lllgtMi|vraquoll bullMl itlsMllVCll IV 11111 lllllslll 111111 ILIIKUM lllraquoraquolaquogtlVlaquol |l ni ittN iimMim |HiMiii in pii-witi m ni ltlin|tiil ut ilimlraquoilaquol pivwiii in iligtlaquo ilhvilvcilin liKnimiiK liuinlim llutt limn IMlaquo A I raquo laquo IM in Iniltlil trnm pump innn| Iiwl ln|iml illaquo lnihlltKIIIIIII hi|iiiil initligt in |iiini|lt linul biwl in lu|i
IH (11 Imlt vill
laquoltplllln| Kpiitiui I bull(raquo bull raquo I US gt laquo A K U i IHIl gt raquobull raquol IyjM
raquo i
KiMniil ihmvn iluw nl ilntt nl hiililiUv n u n luinl t i IIIIIIIIIOMII iliMmUinl raquoM ImhNiivinuwit bull I Civ linnillnH igtilaquo in Itmi pump Imwl I IIISSIIMII IIUIIIIIH ill lninliin In IMIMIII
III limp mill IHIIIIIU bull Inlnnp bull (ligt bull IliMJo llim llnlaquo w p j u l m llflltLllnl l l l l n i i | i
l i p u i m i I bulllaquo bull gt laquo l laquo IKH gtill M raquo O 1 raquo
22
214 The void fraction of the liquid after it leaves the I
Me separator n u n be known in ordrr to evaluate the bubble separator efficiency Densitometer mstrumenta-IWB (unwf a digital voltmeter for readout was mrtalrd at the loop and tesu were uumr using 0 3 0 0 ( 1 1 X 0 z dnsecl i raquo T a ece The effccu of void fraction were shambled by inserting pontic sheets 3 and 6 nms |0J07copy and 0152 mmi thick between the
detector and by using the mrtamc shim side m m k n steel cahVratioa plates 10 to 250
mis (0254 to 6 J 5 mm) thick which were designed for rhraquo purpose
The nail cncounteied dming dealupmtnt testing uras stal peestnt The hourly drift would be equivalent to a
efficiency of shorn 10 a h operation (assuming a void fraction of 0J
at the - c ^^hMe separator) Thus short-term tesraquoi wnl be required to ntmnunt the bdbbk jcparaior efficiencies
bullused on densitometer readings the bubble-separator efficiency was greater than 98 at various operating conauuons with water whkh it shghtty predtcted
Ft Ft
Fraquos
Ft
A -
of liquid gar interface m pump bowl bubble surface area in puop bowl bubble surface area in loop gas concentration in pump bowl gas space gas concentration sn pumn bowl hauid gas concentration in the loop bubbles gas concentration in loop liquid gts concentration m pump bowl bubbles gas concentration in gas purge entering the pump bowl gas space flow of total off-fas from pump bowl gas fltow rate to bubble generator nqiad flow from bubble separator via the bum salt separator to the pump bowl (assume no bubshybles) fountain flow (liquid and buboto) flow of gas purge into pump bowl gas space flow of liquid and bubbles from pwnp bowl to loop mass transfer coefficient for gas dissolved in pump bowl liquid to gas space in pump bowl mass transfer coefficient for gas dissolved u pump bowl liquid to bubbles in pump bowl mass transfer coefficient for dissolved gas in loop liquid lo bubbles in loop liquid
K Henrys lr~ (solubility) coefficient Q flow of bruid and buttles to bubble separator A universal gas constant r temperature
V laquo total gas volume in pump bowl V2 mlumt of wquuland bubbles m pump bowl VL = volume of drcubnutt liquid and bubbles i
loop c ( bubble separator efficiency tf efficiency for separation of bubbles from founshy
tain Aow bull t z void fraction in loop fluid
ltbullgt void fraction m pump bowl flutd
2-2 COOLAKt-SALTnamOUXX FACaUTYKSfF)
A N Sunt
Modifications to the sak coM trap (SCT) were com 1 and the loop was started up on March 14 and operated for 1279 hr to check the effcetrve-|975
of the sail titer to obtain data on salt different operating condrtmws
off-gas sample dau m preparation Work was completed on design
and checkout of the trita the tritium test
generation rates and to obtain salt and for the tritium tests fabrication addition system started At the end of the report period two tritium additions had been completed aad plans were being made for additional tririum addition tests as well as tests designed to examine how the tritium behavior is affected by the infection of steam into the sail
221 Laap Opossum
The SCT flow tnes were disconnected from the sysshytem and the loop was started up on March I 1975 The loop operated continuously until May 6 1975 when it was shut down to permit insinuation of otnp-ment in the containment enclosure for the tritium tests The loop was started again on June 271975 and it was saB in operation at the end of the report period when more than 2500 hr of operating tune had been togged without pHajgmg in the off-gas tine This is convincing evidence that the salt nust filter has been effective since the off-gas Ime had piuggct after only 240 hr of operashytion before the nasi fdier was instated
The loop is operating at a pump speed of 1790 rpm (estimated salt flow rate 54 literssec) and a pump bowl
2 A N San MS 2$ 1975 OKNL-50t7t 25
J IMttI
Avar Rrp Frb
23
praquo overpressure ol 2hi X IU5 Pa (20G0 mm 1 absi The pump bowl oit-^u flow which consuls ui helium coniammg a tew percent of BF prm trace quantities ol condenuMe material is about 2 litervmm iSTPl- The BF i concentration ltraquoi the oil-gas rraquo a tuncnon ol the bull1-1 partial pressure in the tail which in lurn raquo a strong unction in the tail lemprfaiuie txcept Im short period raquoi lime when special tests required a different retime the valt circulating tempetature haraquo beet mauv lamcd ai 535 lo 540 ( at which pomt the BF concenshytration in she oli-ga dream is about 25r by volume The loop otf-garaquo stream emepf tor a 100-cm1 turn wmpk gti ream iv paued through a 72(cuht iraptdry ice alcohol bath | Material which is a dtn while toiid ai itap temperature and a dirty brawn ilmd upon warmshying to room temperaiuie and which is rich m tnimm (about 1(1 nO el continue ilaquogt collect m the cold trap at a rale laquogtt I igt lOngcm (STPlotKff-ga Thnmaie-iial rraquo believed lo be a variable mixture who- compos-lion depends on the relative partial pressures ol BF HFand H Ooser the salt (see Sect 41i
A ol 000 on Auguvt 31 Ilaquo75 the bullop had accushymulated 3073 hr ol sail circulating tune smce being reactivated in Decembei |raquo74
222 Salt Mat Test
Bemeen March 25 Ilaquoraquo75and April 24 Iraquo75 a series ot icsigt wj run lo determine ihe concent ration ot wit
t m the off-fas stream as a runctwu ot a l t tempera-lure aad BF flow for each lest the loop operating coadaioas were set at the desired values ami the off-fas stream was shunted through a metamc 5- to deg-m (iter whKh was inserted mto the ait-sample access nozzle on the pump howl The sal mat concentration was calcushylated usmg the fan m weight of the filler aad the total flow sf fas A total of tea teas were earned out The test tune was nnrmatty about 12 to 15 hi but in two cases it was shortened tc about 3 hr because at the buildup ot a high-preawiie drop acroa the fdter Pump bowl pressure was 2Jb7 X 10 Pa and total off-gas flow was 1 litervmm (STP| When BF was added to the helium entering the pump bowl the BF flow was ad-msted raquo (bat the BF partial pressure m the mcomuig gas was the same as tFe calculated psttial pressure of the BF over the salt asswmng the eutectic mixture ot NaBFlaquo acd aF The salt drcutatiag temperature was controlled at either 535 or 620degC The observed conshycern rations ol mtst m the off-gas (Table 22) ranged Irom MOO ng on ai the loner temperature ibdquo as mgh agt 500 ng cm 1 al the higher temperature At the lower temperature where the expected partial pressure of BF in the sail raquoalaquo low the addition of BF with the cover gas was ineffective m reducing the amount ot ~ist in the off-gas At the hajtter temperature Hugher BF
P 27
23 CSTTi 175
VJ St Bt rcmrvrjrurr ijpampr rtlaquoraquo
t gt prepare iraquom mmSTPgt bull mm tic
raquo
Sjir imit iltgtikrgturjiraquogtn IIK Jr o n laquorr if-jtni
2fraquo |ltraquoS
raquo 25laquogt
5
Ifco
Klt-tft Zgt
5 5-532
bulltnrrlaquoflr 4Vlt
H
ion
Avrufr laquoi
11 i KX
KvrisfX 15
Vtumi^r Ih niKviic bull HtipgtltJium
24
partial pressure in the salt) a significant reduction was observed in the mist concentration when i lFj was added with the cover gas However it was not reduced to as low a value as at the lower temperature These results whie not completely definitive suggest that bull F evolution from the salt may no be the only mrst-producing mechanism in the pump tank that is simple mechanical agitation of the salt in the pomp bowl may abo produce some mist In addition no data were obshytained with excess BFj concentrations m the cowr gas Since the mstaflatioR of the salt-rust iHter in the off gas line was effective in eiumnating the operational probshylems in the CSTF caused K v the mist further investigashytions of methods to lirnii or control the mist have been deferred m favor of experiments to study tritium beshyhavior in the system
The decision to use tritium rather than deuterium a a test gas4 in the CSTF necessitated additional design effort and a somewhat more elaborate test setup in order to satisfy apubcaMe radiation safety require-meats A conceptual design was prepared for he tritium addition system and a preimnnary radiation safety analysis was performed for the proposed test Engineershy
ing design procurement fabrication and msiaBauon of the tritium addition system were completed by the third week m June 1975- The addition tube and the addition procedure for tritium are essenttaly the same as those devised for the addition of deuterium The rwer tube of the addition assembly is pressurized with hydr-jgen contanung a small amount of tritium and the gas is avowed to diffuse through the Hastefloy N tube which loom the lower end of the addition tube and which is immersed in the flowing salt stream (see Fig 2oraquo The HasteSoy N lube is 120 mm long by 127 mm in OD by 106 mm m ID and provision p made to fasten metanurped specimens to the upstream faje The portion of the addition tube inunedntely adjacent to the HasteRoy N section is surrounded by an evacushyated annuius monitored to check for extraneous tritium leakage The hydrogen-tritium mixture is passed through a purifier (M-Ag tube) to remove impurities such u O Ngt and H G which might interfere with the permeation process The probe volume ~p (infecshytion tube plus adjacent tubing) and a calmrated refershyence volume are interconnected and pressurized with the H - T mixture at the start of the test The two volumes are then isolated trom each other whne the addition rs in progress At the end of the addition
-Owe 75-T2CW
TRITIUM TRANSFER CYLMOER
4 0 0 C
sect laquo r 2^
1 SAMPLE
VACUUM ltS)
ampQ- ]
HYDROGEN
VACUUM ANNULUS
INJECTION TU8E
|StT2
35-C
lOO-C
FLOW 532laquoCi
Fig 2 T w mdash aUthnm ygtw far CiSTF
25
period the difference m pressure between p and V is recorded then the two volumes are equdibrated and the final equilibrium pressure is recorded The initial and fwal pressures ir lppx and pz respectively the foul equilibrium pressure p and the known volume and temperature ot lgt are then used to calculate the amount ot fas which pernxated the addition probe according to the equation
laquogt PiPi Pi V bdquo = _ x ^ try Pzraquo PT
where n is (rK number oi moles ltgti gas transferred R is the molar gas constant Tr is the reference volume temshyperature and the other symbols are as previously deshyfined
During the addition the amount oi extraneous leakshyage i calculated from pressure rise measurements in the evacuated annulus and this quantity is subtracted trom n to obtain the net amount oi gas iransierred into ihe salt The tntium content ot the hydrogen-tritium mixshyture is determined by mass spectrometer anaksu and Ihe net amount ot added tritium is then caicuiated
Tritium land hydrogen) which enters the salt stream rs assumed either to rematR in the sail laquo iraquo leave ihe sail by one ot two paths eiiher hy permeation through the walls ltgtl ihe loop piping or by irartsler to the gas phase in ihe pump howl or in the sail monitoring vessel iSMYl and leaving the loop raquoih the oii-gas stream During and ailer ar addition the tritium conieni ot the sail is monshyitored b lakmg samples raquot salt trom ie sail pool n ihe pump bowl or in ihe SMV and ihe irmum content oi ihe oil-gas stream ts rrhMMored hv takiru sampics from he oii-gas line ai a point ahoul I m downstream bullgt ihe rramp bowl The oil-gas sample stream is pasted first through a water trap to collect chemicaiiy ^gtmh-neltl I water-slaquo M unlet tmium and then through an oxidizing atmosphere to convert eiemeniai iriiium io iniiaied water raquohkh is c-iliecled in a seciid irap The tritium conieni oi the salt samples and ltraquoi hoih ihlt oil-gas samples are determined hy a scintillation cHinimg techshynique During the iniiul tritium addition experiments no provision was made IlaquoH measuring loop wait petnva-lion so lhat ihe tritium lost hy this mechanism is assumed |o he Ihe ditferenlaquoe hefwven the arnouni of Iniiiim aided and ihe sum oi the quantities w-hich ieave in ihe oii-gas stream and which remain in the sail
firing the March 14 Igt~v | 4 y |ltrgt bdquopei almg period a number of sail and off-gas samples were taken fo obtain baseline raquoaJues |o minim concenira-lion and lo shake down and evaluate the sampling tech-ii-ities During sluiidown oi lthe CSTI- in Magt and June
Iraquo75 the intium addunn probe was msiaUed in the survediance-spei-onen access tube and the final installashytion work was done on the tnUum addition system A stainless steel valve (HV-255AI and some stainless steel tubing which were part of the original off-gas sample-line installation were removed and replaced with a Mood valve and Hastelloy N tubing because it was ieii that the Monti and HasteUoy N would be less likely to react with the off-gas sample stream Two 2-5-cm-diam X 45-cm-long KastelkA N lubes were filled with sail from the dram tank and set aside as representative samples oi the salt as it existed prior to the start oi the tntium tesis-
On June Z~ I~5 the mop was filled and salt cirvuia-tion was resumed Several additions o i hydrogen raquoere made to check out the operation of the addition system aid to obtan data on permtaiior rates A loul or bull J cm M f l oi hydrogen was added in ihese rest and the last addition lt raquol an STPraquo was made -gtn July Jfs Ilaquoraquo~5 with ihe addition tube pressuried to I_gt~ X It) Pa the measured permeation rale was about laquo cm hi ipared with a predicted value i raquo era hr The Iirsl addition o iriiium was made on July l~ i _ 5 and a second addition with CiHlditmns essenziaili he same as iraquor the fust additnm was made August 5 1 _ 5 In each case sail and oii-gas samples were taken during ihe tritium ad Inigtft lahoui 10 hri and or atgtraquou 2 weeks afterward until sample resuiis indicated Tf at the intium levels had returned io iheu pretest values or had Mahihed Oaia lot calculatufi o ch-e amount o addej ps are sin win in Tabic _ A maihemaiica analysis and discuss of ihe tampie results are presented in Se^ i i
TaMr 2J Jtwtmm JMIIPO 4U far CSTI rnf
f rr runilv-r 1 i lraquojrc ~ ~y s r
ti4iilaquon vijrTrJ i raquo bullxt ltMiri-n erxteJ - gt lt o -gti VMiTfcltn -aw bullgt t N bull Im-ijS p-i-uir^ TjiTa i s j r bull bull bull 1 raquoUl prcraquoMraquorf p~ ltti bullraquo laquo bull r - t |utftt -nm p-riu-r r f^i a bull laquobull 1 bull 1 r v-jirrlt- m i i gt i i
fr Tcmr^r 4u-r k bull laquo lt l l bullbull ltrr gt rv-Tltjriraquor - r m -raquo raquo i 1 bull bull raquolt--laquo-f i e j l -j -lt- rn bullbulllt raquo raquo 14
i--tTWjTl-raquon - J 7T1 bull - raquo bull bull gt |TTti-n -raquonltf n TilaquoT in nisfi ii bull bull bull
ra^ pr^i l--l i m u M e i laquo m i it it X bull bull
1 bullbull J irmm j dea bull ml 11 raquolt bull
26
2 J FORCEftCONVECTlON LOOPS
W R Huntley M D Silverman H fc Robertson
The Forced-Convection Corrosion Loop Program is part of the effort to develop a satisfactory structural alloy for molten-salt reactors Corrosion loop MSR-FCL-2b is operating with reference fuel salt at typical MSBR velocities and temperature gradients to evaluate the corrosion and mass transfer o( standard Kistelloy N Addition of tellurium to the salt in MSR-FCL-2b i olanned after baseline corrosion data ire obtained in me absence of tellurium At this time the loop has operated approximately 3000 hr at design ST conditions with the expected low corrosion rates
Two additional corrosion loop facilities designated -ISR-FCL 3 and MSR-FCL4 are being constructed They arc being fabricated of 2T titanium-modified Hastelloy N alloy which is expected to be more represhysentative of the final material of construction for an MSBR than standard Hastelloy N
2 JI Operation of MSR-FCL-2b
Loop FCL-2b was operated continuously for about 3000 hr from February to June lraquo75 unuer design ST (565degC minimum 70SdegC maximum)conditions During this period standard Hastelloy N corrosion specimens installed in the loop in January 1975 were exposed to circulating fuel salt at three different temperatures (565 635 and 705degC) As expected corrosion rates were low the highest value was 01 mil year Ojimyear) at the highest temperature station
Salt samples taken at intervals have been analyzed for major constituents metallic impurities and oxygen (Table 24) Except for an occasional high value for oxygen or iron the analyses are relatively consistent and indicate that the observed corrosion processes have had very little effect on the concentrations of the various species present in the fuel salt Analytical probe readings for the VIU ratio indicative of the redox condition of the salt have been taken on a weekly basis This ratio which wraquo about 7 X I0 3 at the beginning of the corrosion run rapidly dropped to about I X | 0 3
after the first 24 hr of operation The ratio then gradushyally fell to A I X I0 1 by the end of March CVI500 hr elapsed time) and it has remained at that level during the latter part of the operation
After the corrosion specimens were removed for the 3000-hr weight-change measurements preparations wei nude for obtaining htat transfer data on the Li-Be-Th-U fuel salt (717-16-12-93 mole ) At this
time a Calrod electric tubular heater failure was disshycovered on the pipe line (i 27-mm-OD X 11-aim-wall) which runs from metallurgical station No 3 to the inlet of cooler No I After removing the thermal insulation about 10 to 20 cm 3 of salt was found on the loop piping and the bumed-out heater Grainy material was present on the heater sheath at three locations directly opposite peeled-off sections of oxide layer on the Hastelloy N piping A small crack (A 5 mm long) was found on a tubing bend directly under the failed heater Whether the heater arced causing the piping to fail or whether the salt leak from the loop caused the healer burnout is uncertain at this time Examination of specishymens from these regions is continuing
The fuel salt was drained from the loop into the fill-and-drain tank after the leak was discovered Analytical results on a sample taken from the tank indicated that no obvious contamination of the fuel salt had occurred A new section oi tradeping was installed (approximately 24 m from metallurgical station No 3 to the inlet to cooler No I) During the shutdown several defective thermocouples and two defective dam-shell electric heaters were replaced Ball valves were refurbished numerous small repairs were made and instruments were recalibrated After the thermal insulation had heen replaced baseline heat loss measurements were made with no salt in the loop in preparation for taking heat transfer data The loop was ready for refilling at the end of aly approximately four weeks after the salt leak was discovered After filling the loop heat transfer measurements were obtained with flowing salt The ALPHA pump speed was varied from 1000 to 4600 rpm resulting in salt flows of approximately 27 to 16 litersmin which correspond to Reynolds numbers that vary from 1600 to 14000 The lower limit for salt flow was set to prevent freezing and the upper limit was dictated by the power required foi driving the pump At the lowest flow rate unusual wall temperature profiles were noted which probably were caused by entrance conditions and transitional flow effects The heat transshyfer measurements were completed near the end of this reporting period and analysis of the data is in progress
The stringers containing the Hastelloy N corrosion specimens were reinserted in the loop and ST operashytion (S65degC minimum 705degC maximum) was resumed in order to complete the originally planned 4000-hr corshyrosion run If no unusual corrosion behavior is encounshytered in the next 1000 hr of operation nickel fluoride (NiFj) additions will be made to the loop in order to raise the oxidation potential of the salt to a level correshysponding to a U^U3 ratio of about I0 3 and a new set of corrosion specimens will be exposed
27
raw t u si tioalaquolaquofcUF-laquofF -ThF-UFlaquo
i-im
Sanpfe Mo
Date impkd (197$)
Total hoars of a i l
arcabboa bullhel saatptcd
Major coapoMMs TIJCC ameiub Notes
Sanpfe Mo
Date impkd (197$)
Total hoars of a i l
arcabboa bullhel saatptcd Li Be Tb U F Fe a f t O C S
lb 1-17 0 78 221 43-2 I I I 467 101 40 23 lt50 I I 99 Flash salt 2b 1-23 48 60 42 52 3b 128 0 799 174 430 an 463 75 70 15 125 29 4 3 New sail 4b 2-11 177 137 63 60 75 Sb 2 18 355 154 64 68 45 6b 2-24 498 98 63 28 48 7b 3-3 676 7 8 236 4 2 J 105 463 147 67 35 45 23 17 bullb 3-25 1146 7UI 255 430 104 458 256 59 57 lt2S 14 9 9b 4 16 1647 816 229 432 097 452 $ 70 30 20 78 15
10b 5-12 2197 829 264 430 103 455 62 85 30 60 l i b 6 4 238 823 225 427 100 445 30 70 25 140 12b 6-23 3173 820 208 433 104 451 35 75 25 152 13b 7-3 3177 830 218 430 10 452 70 80 40 30 FaVaaa-dran
oak Mb 8-7 3246 728 203 454) 100 450 45 85 70 58
7|7-16-i2-03 mole bull
232 Desia Mid CoastnKtkm of FCL-3 raquossrfFCL4
The design work for FCL-3 and FCL-4 was essentially completed any changes or revisions which occur during construction of FCL-3 will also be made on FCL-4
The piping support frame for FCL-3 was installed and installation of electrical equipment is proceeding- Conshyduit lines have been fin from the variable-speed motor-generator set on the ground floor up to the electrical rack installed on the experiment floor and a sizable
number of transformers starters switches etc have been installed The instrument panel cabinets have been positioned and cable trays are now being installed Fabrication of two ALPHA-pump rotary elements and two pump bowls is 90 complete A large number of completed items for both loops (eg dump tanks auxilshyiary pump tanks cooler housings blower-duct assemshyblies electric drive motors purge gas cabinets etc-) are on hand awaiting installation Fabrication of the titanium-modified IrasteHoy N tubing for the salt piping of the loop is in progress
Pan 2 Chemistry
L M Ferris
Chemical research and devdopmen rdated to the design and ultima^ operation oraquo MSBKs are itill conshycentrated on fuel- and coolant-salt chemistry and the devdopment of analytical methods tV-r use in these systems-
Studies of the chemistry of tellurium in fuel salt have continued to aid in elucidating the role of this dement in the interranular cracking of Hascdioy N and related alloys An important initial phase of this work involves ihe preparation of the pure tellurides Li Te and LiTe3
for use in solubility measurements loop experiments clectroanaiytical studies and studies of tellurium redox behavior in molten salts Technique for preparing these idlurides have been developed and experimental quanshytities have been prepared Spectroscopic studies of tdlu-rium chemisfy in m-jlten salts and of the equilibrium H(ggt + UF 4 |d) = UKj(d) + HF(ggt have also been
initiated In work using molten chloride solvents at Lust tvo light-absorbing tellurium species have beei shown in be present These species are as yet unidentishyfied but have compositions in the range Li2Te to LiTe4 Preliminary values of the quotients for the above equilibrium have been obtained using LiBeF4 as the solvent These values are in reasonable agreement with those obtained previously by other workers
A packed-bed electrode of glassy carbon spheres was constructed calibrated with Cd1 ions and used in experiments with Hi1 ions in LiCI-KCI eutectic It was concluded that this electrode was prototypic of orie (hat could be used for the electroanalysis or electrolytic removal of bismuth oxide and other species in MSBR fuel salt Preliminary experiments were also conducted lo evaluate some questions relating raquoo the mixing of fuel
and coolant salts The results suggest ihat or mixing small amounts oV coolant salt with large amounts of fuel sal the rate of evolution of BFj gas will not be intolershyably high and that somj oxide can be present in the coolant salt without effecting precipitation of L0 or ThO - Lattice enthalpies of first-row transition metal fluorider were calculated to provide a theoretical basis for evaluating thermochemical data gtr svructural-metal fluorides
Work on several aspects of coolani-sait chemistry has continued Analyses of condensates from the Coolant-Salt Technology Facility (CSTF) indicate that the vapor above (he salt is a mixture of simple gases such as BFj HF and H 0 rather than a single molecular compound Tritium concentrates in the condensates by about a factor of 10 s relative to the salt Studies of the system NaF-NaBF 4-B 0 at 400 to 600degC show that at least two oxygen-containing species aie present in typical coolant salt One species is Na B F 6 0 j while the other has not yet belaquon identified
The development of analytical methods for both fuel and coolant salt was also continued An in-line voltam-metric method was used to monitor U^U 1 ratios in two thermal-convection and one forced-circulation loops Two additions of tritium were made at the CSTF The salt in the loop did significantly retain tritium and the tritium ultimately appeared in the off-gas Work was begun on using various electrodes for determining iron in MSBR fuel salt Previous work had been conducted with solvents that did not contain thorium Preliminary voltammetric experiments were conducted to identify soluble electroactive tellurium species in MSBR fuel salt
28
3L Fuc-J-Scik Chcmism
ADKeimers
31 COMPOUNDS IN THE LITHIUM-TELLURIUM SYSTEM
D Y Va^ntine A D Keimers
It has beei k-mcns rated that tellurium vapor can induce shallow grain-boundary attack in Hasiefloy N similar to that observed on the surfaces of the fuel-salt circuit of the MSRE However the actual oxidation state or states in which teilunum is present in MSBR fuel salt an LiF-BeF-ThF4-UFlaquo mixture and the chemical reactions with the Hastelloy N surfaces remain to be determined The lithium-tellurium system is being investigated to determine which Li-Te species can be present and to synthesize samples of all possible lithium tetlurides- The solubility of these compounds in the fuel salt will then be determined In addition they will be used in spectrophotometry- and electrochemical investishygations of tellurium species in melts
During this report period sample of LijTe and LiTe
were prepared The preparations were made in an argon-atmosphere vacuum box equipped with an enshyclosed evacuated heater which held a molybdenum crucible All handling of Li-Te compounds was done in inert-atmosphere boxes sometimes the compounds were sealed under vacuum to minimize oxygen nitroshygen or H 0 contamination Lithium having an oxygen content of ltI00 ppm was supplied by the Materials Compatibility Laboratory Metals 2nd Ceramics Divishysion Tellurium metal of 99999 wt Tr purity was obtained from Alpha Ventron Products
The Li2Te was first prepared by dropping small pieces of lithium into molten ellunum contained in a molybshydenum crucible at 550degC The reaction was extremely exothermic emitting fumes and light tlashes after each lithium addition Solid formation occurred at lower lithium concentrations than expected from the reported phase diagram2 Further lithium additions continued 10 be absorbed after first melting on the surface of the solid phase An amount of lithium necessary to satisfy Ihe Li2Tc si gtichiomeiry was taken up in this manner However because of the loss of vapor and of some solid material which splashed out of the crucible during the early additions of liihium it is doubtful that the stoichi-omclry was in fact preserved
The x-ray diffraction pattern showed a single phase identified as LijTc having a face-centered cubic strucshy
ture with a lattice parameter of 65119 t OJ0O0Z A J
The oxygen contamination in the product totaled about 375 ppm- Spectrographs analysis reported 0-5 wt ~ molybdenum present Since the oxygen level and moshylybdenum impurities were fairly low a larger-scale prepshyaration wts attempted as well as a direct preparation of LiTcj by the same method In both cases rv product was contaminated unacceptabiy with molybdenum and these preparations were discarded Apparently the first preparation had affected the surface of the crucible such that the reaction with molybdenum was accelershyated in these subsequent experiments
The molybdenum crucible was used for one further preparation after cleaning and polishing the inside surshyface The Li Te was prepared from the lithium-rich side of the phase diagram by dropping tellurium info molten lithium Since molybdenum is relatively inert toward lithium4 less reaction with the crucible was expected In addition this preparation could be made at a much lower temperature The tellurium was added to the lithium in small increments with the temperature held at 250degC Each of the first additions resulted in a smooth quiet reaction with a solid phase forming on the bottom of the crucible However since completion of the reaction was not visibly apparent the temperashyture of the system was increased above the tellurium melting point to about 550degC to ensure that unreacted tellurium was not on the bottom of the crucible More additions of tellurium were then made Above 500degC a popping noise was heard after each addition of tellushyrium After about three-fourths of the tellurium had besn added the system was mostly solid As more tellushyrium was added the amount of solid in the system became so great that further additions of tellurium were
I A D Keimers and D Y Valentin MSR Program Semi atmu Profr Rep f-eh ltlt 1975 ORNL-5047p 40
3 P T Cunningham S A Johnson and F i Cairns Vlectrmhem Soc Klrcirochrm Set Tech 120328(1973)
3 X-ray lattice parameters were measured by O B Cavin of the Metals and Ceramics Division The value 65119 00002 A measured tor IiTe is in agreement with the value 6SI7 A reported by K Ziml A Harden and B Dauth Hlektrochem 40 588 11934) The value 61620 bull 00002 A measured for LiTe is in agreement with the value 6162 A reported in ref 2
4 H W leavenworlh and R F CUaryAcu Mel 9519 11961)
29
30
not covered by the liquid Subsequent additions proshyduced light flashes and poppng associated with the highly exotherrmc reaction as encountered m the preshyvious preparations oi Li Te FuuBy enough additional tellurium was added to the sgt-stem to satisfy the Li Te stoictuonietry and the system was aflowed to cool to room temperature
Upon crushing the cooled product fow differently colored substances were distinguishable gray opaque material wine-red to pink opaque material colorless translucent crystals and metafile tellurium Analyses were performer separately on each type of material
1 Gray opaque material The x-ray diffraction pattern revealed LigtTe and LiTe no other lines were present The oxygen level was about 218 pom Specshytrograph analysts indicated the presence of about 01 w t molybdenum
2 Red-hue material Only a few crystals of all-red material could be isolated The remainder of the red-hue material was ground together with some surshyrounding gray material The x-ray diffraction pattern corresponded mainly to Li2Te A small amount of LiTe was also preset The oxygen content was reported to be about 275 ppm Spectrograph analysis reported lt00I wt 9 molybdenum
3 Colorless translucent nd isolated red crystals Both these products gave an -ay diffraction pattern corresponding to pure Lij Te with no indication of a second phase
To ensure a uniform product all the various colored materials were recombined and thoroughly mixed The LijTe mixture was then placed in a 2-in-diam tungsten boat which had previously been enclosed in a quartz bottle The quartz bottle was then evacuated sealed and heated to 550degC for about 16 hr The product obtained after cooling was almost completely cream-white However when the bottle was broken open the product began to turn beige upon exposure to the envishyronment of the inert-atmosphere box The product was then crushed roughly and placed in sample bottles On standing in the bottles the product gradually reverted to the red-gray color it had been before the heat treatshyment with the exception that the product in one bottle remained beige The reason for the lack of uniform behavior is as yet unknown Some of the darkened product was returned to the tungsten boat in another quartz bottle and (he heat treatment repealed it again turned the cream-white color The products both the light beige and the red-gray color forms gave x-ray difshyfraction patterns for a single phase LijTe Analysis of this LijTe is given in Table 31
T l r 3 J ABMywafU-TcaaJliTc
UU t i l r
l l lVI 1 laquo 5 - MI 1 - bullbull It IWI ~ raquo raquo - bullbull 5 Sraquo 4 r II 5
Li TV IMgt4T I mj r i LiTe bullbulln4r ~ bull 14- 05 XI lt - 5 raquo Innh4r ~ l ITI - 1511
-fjgt diftraciMi SMctcpfc SWfJr rhue 0ypm ipeani 740lltr l 275tMrri
MatyMtmdash i w i 005 ltlaquoraquo0I
T w p m iwt i lt00l lt 0 laquo l
Red-gray Li2Te was mixed with the amount o( tellushyrium required to satisfy the LiTe stoiduometry The mixture was then sealed in a qurtz bottle under vacuum and heated to 550degC for 2 hr The not liquid was dark metallic gray On cooling the solid appeared bright silver-gray The x-ray diffraction pattern conshyfirmed the presence of a single phase LiTe having a near body-centered cubic structure with a pscdo-ell lattice parameter of 61620 plusmn 0D002 A J The well-exposed Debye-Scherrer diffraction patterns suggest that the structure of this compound is more complex than previously reported2 Work will continue in an effort to describe this structure The oxygen content was reported to be 275 ppm Spectrographs analysis reported no molybdenum or tungsten contamination Analysis of this LiTe3 is also given in Table 31
3 2 SPECTROSCOPY OF TELLURIUM SPECIES IN MOLTEN SALTS
B F Hitch L M Toth
A spectroscopic investigation of tellurium behavior in molten salts has been initiated to identify the species present in solution and to obtain thermodynamic data which will permit the determination of the species redox behavior in MSBR fuel salt A previous investigashytion 1 had indicated that Te~ is present in LiF-BeFj (66-34 mole ) on the basis of an absorption band occurring at 478 nm when LiTe was the -Jded solute however the work wai terminated before these observashytions had been fully substantiated The current work is an extension of those earlier measurements which
5 C K Bamberger i P Young and R G ROM Inorg Suel Chtm 36115raquo U974)
31
should lead ultimately to a measurement ol redox equishylibria such as
LiTe bull H bull 5LJF = 3Li2Te bull 5HF II)
^Te bull LiF + ^ H = LiTe + HF 1
These data should then permit the prediction of teilu-num redox chemistry as a function oi LF gt l T F 4 ratio
During the past several months most ot the effort was devoted to assembly oi the apparatus necessary for the fluoride measurements Ths involved fabrication and assembly- ot the following furnace for the fluoride studies diamond-windov ed specirophotometrk cells a vacuum and inert gas system and a KHF saturator through which H is passed to generate HF-H mixtures of known proportions
Also during the period of preparation some attention was given to a supporting study in chloride melts The advantages of working in chlorides are
i previous ground-work investigations have already been reported7
2 chlorides are easier to hold in silica cells without container corrosion
3 the greater solubility oi the tellundes in chlorides may reveal greater detail because oi more intense spectra
Atsorption spectra have been measured for LiTo LiTej and tellurium solutes as well as during titrations of LijTe with Tej in the LiCTKCl eutectic 31 450 to 700degC These data indicate that at least two light-absorbing species are present in molten chlorides conshytaining lithium tellurides with compositions in the range LiTe to LiTe4 Furthermore an examination of Te 2 in the LCl-KCI eutectic has indicated thai there is a second species present besides Te which is formed at high temperatures andor high halide ion activity More detailed experiments are anticipated using purer lithium lelluride solutes in the diamond-windowed cell to demonstrate (hat (he additional species are not related to impurities from the reagent or silica corrosion
6 This work has done in cooperation with J Bryncsfad of I he Metals and Ceramics Division
7 I) M Cruen R I McBclh M S I osier and ( Y (roulhiimcl Phys Otcm 70i2t472 (l6gt
3 J URANIUM TOTRAFLUOftDE-HYMOGEN EQUIUHUUM IN MOLTEN FLUORIDE SOLUTIONS
L O Gilpatnck L M Toth
The equilibrium
LF 4ldraquo4H2lg) = UF J ldraquoHF|g) HI
is under investigation using improved methods of analyshyses and control The effects of temperature and solvent composition changes on the equilibrium quotient
Q = rraquo
are the immediate objectives of this work and are sought to resolve previous discrepancies noted in fuel-sal redox behavior
The procedure involves sparging a small (approxishymately 1 gl sample of salt solution (UF 4 concentration of 0038 to 013 mole liter or 0065 to 022 mole rgt) with H gas at 5S0 to 850degC until partial reduction of UF 4 to UF 3 is observed HF is added to oxidize the desired amount of LF j back to UF 4 When an equilibshyrium between the HF H gas mixture and the UF 3 -UF 4
in solution is reached a spectrophotometric determinashytion of the UFj and UF 4 concentrations is made These data are combined with the analytically determined HF(H2) ratio to obtain the equilibrium quotient at a given set of conditions
The assembly of the system for this experiment has been completed and measurements of equilibrium quotients using LiK-BeF (66-34 mole ^) as the solshyvent have been initiated Some delay has occurred because of trace water in the HFHj sparge gas which was responsible for the hydrolysis of uranium tetra-fluoride and the subsequent precipitation of 1 0 The problem has been partially alleviated by treatment of the KHF saturator gas supply lines and spectrophotoshymetry furnace with fluorine at room temperature Howshyever back diffusion of water vapor into the furnace from the exit gas line has also caused substantial solute losses and has been reduced by using higher HF-H2 flow
This research in support of the MSBR Program was funded by the KRDA Division of Physical Research
H I O Gilpaimk and L M Toth The Uranium Tetrafluoridc Hydrogen Fquilihnum in Mollcn Fluoride Solushytions MSR Pnygram Srmunnu Progr Rep Feh u 7 s ORNI-5rt47p43
32
rates Together these modifications have reduced the totute Kisses to an acceptable level (2^ per day i
Equilibrium has been achieved at 650X lor measured I F VFj ratios of approximately 02 X IG to X 10- Although the I F VF 4 values are reproducible a fixed KHF saturator temperatures the aaalyiicaily detennined HF values are not as yet Consequently the standard error (approximately 50lt) in the equilibrium quotients is soil rather high So tar a value ofQplusmn 10 has been determined at 650degC which compares favorshyably with the previous value of 116 X I 0 T Most of the immediate effort is being Jevoted to improving the precision of the HF determination
Tritium control in an MSBR would be favored by higher equilibrium quotients In an MSBR the I F UF 4 ratio will probably be fixed by equilibria involving the structural metals The tritium inventory will be established by the tritium production rate and the various tritium removal processes UQ is larger than previously anticipated the partial pressure of HF would be higher and the partial pressure of H would be lower than previously estimated Thus TH would be available at a lower concentration for permeation through the heal exchanger to contaminate the coolant loop (and ultimately the steam system) and a larger proportion of the tritium would be present as TF which would be removed in the helium gas stream
34 POROUS ELECTRODE STUDIES IN MOLTEN SALTS
H R Bronstein F A Posey
Work continued on development of porous and packed-bed electrode systems as continuous on-line monitors of the concentrations of electroactive subshystances especially dissolved bismuth in MSBR fuel salt In previous w o r k 1 0 a prototype parked-bed elecshytrode of glassy carbon spheres (MOO microns in dishyameter) was tested in the LiCI-lCCI eutectic system Linear-sweep voltammetric measurements carried out in the presence of small amounts of iron and cadmium salts showed that the cell instrumentation and auxilshyiary systems functioned successfully and demonstrated
9 G Long and F F Blankenship The Ftahiliiy of Uranium Triflimhde ORNL-TM-2065 Part II (November 1969) p 16 Kq 6 with xjyt - 0002
H H R Bronstein and F A Posey MSR Program Semi-anmi Progr fP raquolaquo Jl 1974 ORNL-5011 pp 49 51
II H R Bronsleir and F A Posey HSR Pro-am Semi-anmi Progr Rep reh 2H IV7S ORNL-5047 p 44
the sensitivity of this method of analysts However these measurements showed the need tot redesign oi the experimental assembly to permit removal and replaceshyment of the cell and addition of substances to the melt
During this report period the redesigned packed-bed electrode of glassy carbon spheres was tested again in LiCI-KCI (5SJMIJ mote ) eutectic since the beshyhavior of a number of electroactive substances has alshyready been established in this medium The packed bed of glassy carbon spheres was supported on a porous quartz frit and contained in a quartz sheath Another porous quartz frit pressed on the bed from above A glassy carbon rod penetrated the upper quartz frit to provide compaction cf the bed ana electrical contact with a long standee steel rod which was insulated from the surrounding tantalum support tube The oiectrode assembly was dipped into the melt so that the molten salt flowed up through the interior oi the bed and out an overflow dot By this means il was possible to obtain a reproducible volume of melt inside the packed-bed electrode
Voitairmetric and coUometric scans of the pure melt at 3raquo5degC showed that the background current was small A typical set of current-potential and charge-pountiai background curves is shown in Fig 31 - A 2-V
1 1 I flmdashImdashTmdashImdashraquomdashbull 1mdash T I mdash T 1 1 T mdashi 1 I I bull 1 l - laquo 0 0
to 0 5 0 0 -OS 10 IS ELECTKOOC P0TpoundlraquoTiraquoi ( n bull laquolaquoamp) (raquobull$)
Ffc 31 Linear-sweep voUMimetry and coalonef ry of cadshymium in LCI-KCI (588-412 mole gt eutcctic with a packed-bed electrode of glassy caboa spheres Curve A current backshyground (sweep rate = 10 mVsec) curve B current with Cd present (sweep rate = 5 mVsec) curve C background charging curve (sweep rale - if) mVsec) curve D charging curve with (d present (sweep rate = 5 mVsec)
33
range ot electrode potential could be swept without evidence of significant amounts ot ouduable or reducshyible impurities in the meli For calibration purposes a known quantity ot -radmium ions lCdgt was added to the melt lraquoy anodiation ol molten cadmium metal conshytained in a specially designed graphite cup which could he lowered into the melt The amount ot cadmium adod (Fig 311 was monitored by use oran electronic autorancui couometer
Following addition ol cadmium the voifammeinc and coulometric scans indicated that only a small fraction ol the known cadi-uum content inside the void space oi the packed-bed electrode was being measured- After removal of the cell assembly examination showed flat the glassy carbon contact rod had somehow fractured possibly due to excessive pressure from the matin stainless steel contact rod and resumed in lo of elecshytrical contact with the packe-i-Sed electrod
The -ell assembly was then redesigned and rebuilt to permit electrical contact to be maintained without undue pressure and to allow accurate measurement of the working volume of the packed-bed electrode The new design was similar to that of the previous cell except that the upper fritted quartz disk was permashynently sealed (o the surrounding quart sheath A small hole in (he center of the disk permitted loading of the daisy carbon spheres into the electrode assembly and provided accurate positioning of the glassy carbon con-act rod into ihe bed Prior to loading of the spheres
the volume contained between the porous quart disks was measured with mercury
Some voltammetric and coulometric scans in the presshyence oi cadmium ions are shown in Fig- 3 1 As in preshyvious studies in aqueous media with the packed-bed electrode2 more accurate analytical results were obtained on Ihe anodic half cycle (stripping) than on bulli cathodic half cycle (deposition) Approximately 40 mC of cadmium was estimated to be within the packed-bed electrode The coulometric results shown in Fig 31 n quite consistent with this value Thus it is possible knowing the geometry raquof a packed-bed electrode to estimate the response and sensitivity within reasonable limits (the accuracy oi estimation depends upon void fraction the accuracy of the volume measurement and other factors) Repeated scans over a period of many days showed good reproducibility and also established that diffusion through the quart frits during the time of measurement (only a few minuus) has very little effect on the results
12 I I R Bronstcin and I- A Posey Otrm Mr Amu Proxr Rep May raquo IW ORiSI 4976 pp 1119 I I
Another cell was pocked with jOOp-dum glassy carbon spheres and used to obtain the results shown m Fig 32- In this case a quantity of amp ions had been anodued into the melt in a manner ssraiar to that used for cadmium- At the time of these measurements the same melt had been in use for many weeks Fig 32 shows voiiammetnc and couloroetric anodic stripping curves in the vicinity ot the anodic peak for stripping oi bismuth which had previously been deposited on the imemal surfaces of the electrode during the cathodic ^ii cycle In agreement with observations of others we found that volatility of BiCl precluded close correshyspondence between added and observed quantities of bismuth and that the bismuth peak decreased steadily with time The appearance of the bismuth peak suggests that possibly some alloying of bismuth with the cadshymium look place
Other expeiiments on bismuth reduction and stripshyping will be carried out in the future in which cadmium used for calibration of the ceil sysreni is absent In addition the present apparatus wiL be used lto study the electrochemistry oi lithium teiluride in the UC1-KC1 euieciic Observations on lb tellurium system in the chloride melt may be useful in interpretation of tellushyrium behavior in later studies with MSBR fuel salt The
CWV-3WG 75 -Z99
TEMPERATURE 392-C if REFERENCE ELECTRODE laquoflaquolaquoCMraquo4r) pound
GLASSY CARSON SPHERE OMMETER -200raquogtCfm
04 03 02 01 00 -Ol -02 - 0 3 - 0 -05 -06 ELECTROOC POTENTIAL (rtAflAflCO (bullraquo()
F J2 Linear-sweep anodic stripping votUmmetry and coglometry of hianiirh efecfrodepooted onto a packed-bed electrode of gUscy carbon spheres Solid lines experimental current-potential and charge-potential curvet in ihe region of (he rmmuh stripping peak dashed lines estimated background charging curves
34
cajxabilify of the packed-bed electrode ot ciasv carbon tfetctci tot monitoring eieciroactrve species n molten sail has hem shown ugt be sattgttactor Consequently p bull aw now under wa raquo design jpd fabrKation ot cells and appaiaius lor sestmc the electrode system in mxten fluoride media induduw MSBR fuel salt- In Msmufh-coatauung fluoride metis whether bismuth iraquo present as Bt or LijBtor both it should be possible 10 identifgt and determine ihe quantities of each species The packed-bed electrode offer hope ut removin as well as monitoring dissolved bismuth m the fuel sail which may be present as a result of the reductive extracshytion process for removal ot fission products
iS FUEL SALT-COOLANT SALT INTERACTION STUDIES
A D Keimers D t Ilealherly
In the alternate coolant evaluation1 several areas of potential concern were defined with regard to the applishycability o( the conceptual design coolant salt | a B F 4 -NaF (gt2-K mole ^ l | for MSBRs These centered primarshyily arogtmd events associated with off-design transient conditions particularly primary heal exchanger leaks which would allow imermixing of fuel salt and coolant salt If coolant salt leaked into the fuel salt the quanshytity and rate of evolution of BF j gas from reaction lt 11
N B F 4 l d raquo o l j U M - B F l g gt bull N a F i d gt u e ^ lt I
would determine the transient pressure surges to be enshycountered in the heat exchancer and reactor Also preshyvious work 1 4 indicated a substantial redistribution of the ions LT Na Be F and BFlaquo~ between the resultshying immiscible two-phase system formed on mixing Lj BeFlaquo and NaBF 4 The solubilities of UF 4 andThF 4
have not been measured in such systems thus the disshytribution of uranium and thorium between such phases and the resulting concentrations are unknown In addishytion if oxide species were present in the coolant salt either deliberately added to aid in tritium trapping or inadvertently present due to steam leaks in the steam-raising system the precipitation of UO2 following mixshying of an oxide-containing coolant sail with fuel salt has not been investigated Therefore a series of experiments were carried out to investigate these areas
I J A D Kelmirs tl al Committer Report hvaluaiion of Alternate Secondary land Tertiary) Coolants for the Molten-Salt Breeder Reactor (in preparation)
14 V K Bamberger C h Baelaquo Jr J P Young and C S Shew MSR Program Semiannu Prop Rep reh 20 I96H ORNL-4254 pp 171 73
The experimental apparatus consisted ot a a u i u vessel heated by a quuri furnace so thai the raquoraquoraquottTvr of the resukmc phases ouid be observed at temp mure and measured with a cathetomrter The quari vessel extended up out of ihe furnace and was closed with an O-itne titling and end plate A nickci stilting shaft driven bgt a constant -speed dc r-fcgtllaquogtlaquo peneiiated the end plate and during live tests was dnven at a speed adequate 10 stir the two phases without appreciable vtsibW dispersion Access for sample fillet slicks was provided through the end plate as was done also for ihe argon inlet and exit lines A very low argon flow main-tamed an inert atmosphere over ihe melt during ihe experiment
Predetermined weights of fuel salt (nominal composishytion LiF-BeF ThF-lF 4 (Mfc-117-03 mole^raquo | and coolant salt |nominal composition NaBF4-NaF (2- mole ltl| were placed in the quart vessel and rapidly healed lo 550 C Bubbles of gas could be observed due to BF) generation via reaction I I I as soon as the coiilani sail melted during the heat up period When the temperature reached 550 ( counted as time zero stirshyring was initiated The volume ol the phases was periodshyically determined and filter-stick samples were taken at 30- or dO-rrun inieials
The reaction between the fuel salt and coolant sail proceeded slowly approximately 30 to raquo0 min was required to complete the visible evolution of BF 3 gas at 550degC When the initial coolant salt content was 20 wt or less of the total material no omlant salt phase remained after approximately I hr All the NaF disshysolved in the fuel salt phase and all the BF gas left the reaction vessel With larger initial weights of coolant salt up to 50 wt gt a small residual volume of coolant salt phase could be observed after I to 3 hr Severe corrosion of the quartz reaction vessel occurred at the interface between the coolant salt phase and the argon cover gas in the experiments with the larger initial weights of coolant salt presumably due to attack of the quartz by BFj via a reaction such as
2BF(g) + VjSiOjfc)- SiF4fggt + fcOjfd) (2)
In experimenis 6 and 7 holes were corroded completely through the vessel wall and the surface of the stirred molten coolant salt phase was exposed to air for I to 2 hr at 550degC
In most of the experiments samples of the fuel-salt phase were withdrawn at intervals of 1 2 3 and 4 hr Samples were also taken after the conclusion of the experiment after the melt had cooled to room temperashyture the quartz vessel was broken away from the solid salt All these samples gave essentially identical analyti-
Tabic 32 Compmiliun of fuel-Mil pliiH- ami cnulani-aalt phatv aflci contact al 550 C
h vpcrimenl No
Initiil imvlmc iwt raquo
Hu-I salt Coolant i lr
100 9( Ho 7l) 61) 51)
o II) o 3raquo 41) 51)
111
tgtHK 6 3 3 604 544 50H 44 0
I uclvill phase (mole gt
Nal IK-1 M i l I T
2 3 93
123 1911 63 366
17J 167 165 155 13 H9
NominaUomnoMUon l i l - -Bc l - -Th | - lt - l l (72-I6-I I7-03 mraquolc bull)
Nominal conipotttion Naltl- -Nul (92-K mole bull I
No coolant-suit phase remained
Not analyzed
115 105 106 |lgt9 96
ID4
I I I
I bull i2 IVH 94
Nal-
191 366 43 9
CoiiliiHvih phase IIIIOK- I
IWI l h l bdquo I T N i S i l
4 4 3H 3 9
ii IH n o l i (150 0 017 1)74 OlOH
lt 31 19
M 0 Nalll
lt5l IK 6 J 33
n 47
16 9
ft
36
cat values therefore tne fuel-salt phase analyse (Table 52) represent an average of 5 to 5 values Further supshyport lor the coateatun that react urns nrroHuK the fuel-salt phase were complete m feO mm c less t shewn In the plots of volume rs time in Fig3J The cootani-sai phase volume decreased raptdry tor about 30 mm due to reaction (1) thereafter the volume chance was slower presumably due to reaction i2h
It was irnpossibie to obtain coobnt-salt phase samples with the flier sticks both because the phase volume was small and the salt tended to dram out of the titer sticks Therefore aM coolant-salt phise analyses (Table 33) were from samples obtained after completion of the experiment and represent only smgje values
The analyses (Tabic 3 Jraquo show substantial redistribushytion of the ions Li Na and Be between the two phases Thorium and uranium exhibited low soiubiity in the coolant-sail phase Neither NaBF4 nor the oxyshygenated tluoroborate compound (represented as B 0 3
in the table) was soluble in the fuel-salt phase Fuel salt stirred in contact with a coolant-salt phase containing up to about 50 mole lt B0 3 showed no precipitation of LO Tht coolant phase compositions were ex-
onNL-DWG 75-raquo3748
rlX Claquo
1 0 -
X T
Cootant Solf Phase -
20 40 60 80 TIME (mi)
100 120
Fit bullbull Votame of coobnt-s-Jt phase and fad-nil phase vs fane in mixing experiment No 6 Initial mixture was 60 wi i fuel salt and 40 wt 1 coolant tall After heatiny lo 550deg C Mining was begun and tht depth of the two phase was periodishycally measured
F-laquo O
I n t u t i laquoaraquo4c bull
factual (bull4jac vilr Ml lt) ViM
l raquo bullbullbull 4gt gt- 5 bullbull bullraquo 4i M bullraquo bull bull bull
bullraquo 5 gtraquo MI 14
raquo - Na Nan bull Li bull ZBc bull 4Th bull 41 bull 4S
pressed (Table 33) m terms of the ternary system MF-B 0-NaBF 4 The compositions are dose to the glass-forming regions of the terra y phase diagram1 for the system NaF-BiC-NaBF where drscete comshypounds have not been established
The following pertinent observations can be made
1 The rate of evolution of BF gas on mixing was low- presumably the rate-limiting step is the transfer of NaF across the vflt-salt interface Thus in a reactor system with turbulent flow the release would be more rapid however these results are encouraging relative to MSBRs in that very rapid gas release reshysulting in significant pressure surges was not experishyenced
2 No tendency was observed for the fuel salt constitshyuents thorium or uranium to redistribute or to form more concentrated solutions or to precipitate folshylowing mixing of coolant salt into fuel salt These experiments do not yield information relative to mixing fuel salt into coolant salt since it was impossible to contain predominantly coolant-salt phase mixtures in quartz at 550C Thus the quesshytion of uranium (andor thorium) precipitation as lF4-NaF complexes as observed in an engineershying loop remains unresolved
3 Apparently an oxide species forms in the coolant-salt phase which is more stable than UOj since no LO-precipitation was observed Thus large amounts of oxygenated compounds could be added to the flu oroborate coolant salt for the purpose of sequesshytering tritium since leakage of such a coolant salt into the fuel salt would not lead to uranium or thorium precipitation
15 I Maya Sect 41 this report 16 H F McDuffie et al Assessment of Molten Salts ar
Intermediate Coolants for IWBRs ORNL-TM-2696 (Sept 3 1969) p 20
37
3 4 LATTICE AND FORMATION ENTHALHESOF FIR$T4tOlaquo TKANSmON^ETAL FLUORIDES
The pnmar bull purpose of (his inveMijpinw is to plaquoraquoraquowde a theoretical bans tor cnttcaiK evaluating the chermir-dynamic data thai raquoifl be blamed in an experimental program recently giiittled with Dmstuti ot Physical Research I undine In thf experureirraquo free enerpes of tormaiion will be deduced from emt measurements ot solid-etectriJyie caharuc ceHs The iirsi-roraquo transition rrcials include common sKucturai metab (Fe i Cgtraquo and other meuls iTi V) which may be used in fcaon or fusion reactors When these meuls are corroded or otherwise oxidized u fluoride media used m these resc-tors meial fluorides are formed reliable thermoshydynamic information for these compounds rs valuable in predicting their chemical behavior in the eactor system
For a metallic fluoride MFbdquo I where n is the valence of the metallic iongt the relationship between lattice enthalpy V and enthalpy ot formation is given by the equation
_y=-X Mgtbdquo nXly- ( I t
The lattice enthalpy is the best of the reaction
Mlggt + nV it) = MFbdquo(c) Craquo
at gtvl5 K The lattice enthalpy is very similar to the lattice energy the latter being someihat more diffishycult to obtain from experimental information 3Jr is the standard heat of formation of MFbdquo(c) A- is the standard enthalpy ltraquof formation at gtHl5 K of the gaseous cation and electrons ((gt formed from the crystalline metal
Hc)Mltg)+ gtlt( g) lt3gt
A-bull- is the standard enthalpy at ZW^K of a mole of gaseous fluoride ions formed from the ideal gases electrons and diatomic fluorine
V2F(sgt + ltr(g) - F (gf lt4gt
The enthalpies of formation for reactions lt3gt and (4gt are deduced mostly from atomic or molecular data Abdquo is obtained by summing the first ionization potentials of M and its enthalpy of sublimation and covcrling these quantities where necessary to 2ltraquolaquoI5 K values of bdquobull are given in Tables 34 and 35 The enthalpy of reaction (41 at gtXI5degKis ol24
Hmrraquotc bull Leal rrv-fcr
lt j l yi 5 4ilaquo 6 2 = si laquo2vraquo bull ltlaquo5i-Tiraquo bull 2 i v 5Slaquogt bullMgtC gt i2Wr 2raquoraquo i raquo f Crl I1 - 5 o5 3 6 - 5 Mnl 2ltgt5 4 - lf raquo 5 1 - I l-lt tif - 5 fc5s raquo - 5 C l - t5 - I f 2 laquo I V I 52 - bull raquo3 5 5 - bullltbull
t u t I I -bullbull 323 41 - - N nraquo I N Mraquo5 25
llaquolaquojgtltn rgt cntui-gt rmdashm lt I raquo-raquo- SRIgtS-IraquoS 34 bullgt cnhjlprs i ^uNinurn-n irin ret igt (atenve raquorjc prpjutraquogto encris sorretttrto irraquom elt 2 N BS Iivhnuai N-te 2gtMgt i llaquoI i ^iinucJ in this intetripibii ^NBS Icchnicjl V-ie bull-raquo 11t11 r V Rrufchiu tr j | iTim ThrmoJvn 6 bullbull( tgtraquo4( iXrrmrd tflaquom vgtlij ltal inkveil emf JJJ snmi in W H Sfcltr|[4i jnd J W Pjiicrv-n -laquoWtmmtm Mfidt 31 4 11 raquo-laquoraquo
f-IV-iF Thermhemif tehlt 2J e j NSRDS NBS 11111 I- Rudiicl jl J Oum rnt AifJ 1213 laquo11^1 NRS TcYhnhil tir raquobull lt fftSraquo
kcal per gram-ion it is based on Popps value 1 7 (34(H) eV) for the clectr gtn affinity of fluorine the dissociation energy lt 15 eV) measured by Chupka and Berkowit and the enthalpy difference of F (ideal gas) raquoraquo Hbdquo listed by lluiigren et al 1
The lattice enthalpies of the divalent fluorides arc listed in Table 34 and are plotted against atomic numshyber in Fig 34 The curious double hump has been intershypreted 2 0 in terms of ngand-field theory By this theory differences between actual values of A and those lying on a smooth curve drawn to fit the data of C a F Mnlj and ZnF are primarily due to ligand-field stabishylization energy (LFSfcl For (his series of compounds
bullThis rclaquoearcli in support of the MSRR Program wilt funded hy iho l-RIA Division of Physiiiil Research
17 II P Popp Xatitrforuh 22a 254 117) 18 W A ( hupka and J Berkowil Oiem Pint 54542h
ii nn 19 R Hullcren el al Selected ialun of the T)icrmltgt
dynamic Properties of the Elements p 177 American Society of Meials Metals Park Ohio 1973
2lraquo P (leor-e and tgt S McCliire p 381 in Progress in Inorganic Chrmisln vol I I- A Cotton ed Inieruience New York I W
M
750
_ TOO mdash
o E
x
690
6 2 0 -
I I I I I I I
I I I i I I I I I Cefj Stfj Traquoj V Crfj M Wgt laquo j MF 2 C 2 amp2 ddeg (T d 1 d J d 4 5 draquo d draquo draquo d
Fltg- 34 Lattice wlnaifiM of 3rf diva l l w i l u Solid circle (bull) are experimental aML catenated from Eq 11)error bars art uncertainties in ampH Open circle (-) are AftL mam Iwand-fldd stabilization energy Tnangks (A) arc aW^ minus both LFSE and Jahn-Tener energy Solid squares ltbull) were estishymated by adding LFSE plus 3 kcalmote as an empirical correcshytion to the smooth cone
the ligands are fluoride ions octahedrally coordinated (except for CaF 2 ) to the cation the ocuhedral field of fluoride ions acts to stabilize the splitting of tf-electron energy levels of the metal ions In a spherishycally symmetrical field the (-electron levels would be degenerate that is be at the same energy In Fig 34 the smooth curve drawn through for example N iF 2
represents the ampHt N i F 2 would have if the field of fluoride ions around the nickel cation were spherically symmetrical Octahedrally coordinated cations with unfilled half-filled or fully filled 2d orbitals will not have a ligand-field stabilization energy hence a smooth curve is drawn through CaF(tdeg) MnF(lt 5) and ZnF2(ltdeg)
Values of the LFSE can be deduced from optical spectra For FeF N i F 2 and CoFj subtraction of optically derived LFSE (Table 36) from bHL yields values (open circles in Fig 34) which are above the smooth curve by 2 to 3 kcalmole Similar LFSE subshytractions for CrF and CuF yield values (denoted by
laquoraquoraquo-raquo
Fhoodc iHf bullraquo- plusmnHL
ikai nMle) ileal mmfT l U a l motel
ScF 3941 2 1112 13224 r 2
w 33 1 3-$ 1222 1374 t 35 V F 2 9 S S I29raquo 1499 O F 277 US 14 I44S l 2 3 ^ I3gt l 143 t F e f bullSHi 13V4 1431 3 CoF mjf 1455-J 1457
N O W 1515-5 bull I 4 9 7 C - F ( 1 2 0 I S M 11520 lt - F 2 7 I3S9 143
bullban pomoMs from C E Moore SSKDS-NBS 34 (1970) earailgiri ot inlilmdashiliun from ref 19 catrnce state preparation energy correctnas from rcf 20-T N KeiaHani cf a l Cktm Tkrrmodrn t90 (1974s eO Kabascfccwsfci et at pp 3343S4 in JMrMftWpaf Iktmso-chematry 4th cd Pergamon Oxford England 197 Derived from toad garantc-cdl emf data gjien in W H Skdion and J W Patterson Less-Common Mruls 31 47 (1973) MBS Tetkmfl Note 270-4 (1969) fjASAF TkermochemicM Ttblts 2d ed NSRDS-NBS 37 (1971) Estanaied m this mvcstiplion hNBS TethmeitSote 270-3 (I96S)
open circles) above the smooth curve by 5 and 7 kcalmole respectively Both C I F J and CuF 2 (and to a lesser extent F e F 2 ) are known from crystal structure data to exhibit major tetragonal depai mdashres from octashyhedral coordination geometry This is attributed to the Jahn-Teller effect 2 which confers an additional stabilishyzation energy (Jahn-Teller energy is abbreviated herein as JTE) For CuF 2 and F e F 2 the JTE can be derived optically (Table 36) When LFSE and JTE are addi-tively applied to CuF 2 and C r F 2 the lattice enthalpy is overcorrected as is shown by the triangles in Fig 34
The methods outlined above can be applied to predict A t for V F 2 and T i F 2 Neither compound would be expected to have a significant JTE The formula used is
(5) Atfpound (kcalmole) = AHL bull LFSE + 3
where A V is the value for the compound lying on the smooth curve in Fig 34 The 3 kcalmole on the right-hand side of Eq (5) is an empirical correction reflecting
21 F A Cotton and C rmced Inortnic Chemistry 1972
Wilkinson pp 5deg0-93 in Ad 3rd rd Inter science New York
J9
OFSEk UTEXwl
IkvWt i lrgtH
H raquo T i 4 r |-ltU| OK laquo bullk-jl BRiic bull id lt
III ik^ai n-4ri
J S - l iraquoraquo I l raquo laquo n f i bulllt bull-
J- T i l bull I l Twr bull Mi t | 5 _ W 3raquo4
Jy gt f rlaquolaquoraquo laquo bull gt lt l | 4J6laquoI 5 laquo raquo l
J O K 1 laquobullbull l l raquo lt raquo I l f M a t l~4im bull bull bull I i
J- YtY 6raquogt - a I4i raquo -9
lt t raquo l 114ml lvi
J t raquo l Z l K I lb 5 Nil- lfc21 T I
J N i l 4 i m 54 lt u l I4UI0 4X4
J lt u K 4iKi 15 bull ~5t l raquo
JVjluc tivcn in D Orlkru Strut I RonJmg Berlin- 9 I 2gt 11raquo~Iraquo unlf otherwise m-JiutrJ l I SI minuinl very rlaquouchlgt i bullbull of Til- BiscJ ltgtn K N i F i l
Ksiirruted by jviumini lWgtq n ihj of Til-
Bjlaquod n iNH i gtVI Klinutrd hy Jraquorlaquonltcn mclhod |igtIX) jr r =1 -raquoltraquo cm --bullraquobullraquo Rouen t-Mirruic from JTI oi CuK Hiraquo-d n K( raquol ( ( Allen and K O Warren Struct laquorraquonWf SWw 9 Igtraquo7 nlaquogt| i
40
1550r
1500-
I I I I ORNL - DWG 75 - raquo3750 r I r
i i i I I l l I I ScF TFj VFj Crf MrF5 FeFj CoFj IWF CvF(ZnF)GaF ddeg d d d 1 (J4 d s dlaquo d 7 ltfraquo draquo d laquo
Flaquo 3 3 Lattice enthalpies of id trivalrnt Amides Solid bulltrclraquo laquoraquoi ace experimental plusmnH calculated from Eq (1gt error ban are published uncertainties in plusmnh Open circles ( ) are Af minus ligand-fteld stabilization energy Solid squares (bullgt are estimated by adding LFSF to the smooth curve
the difference between theoretical and thermochemical lattice enthalpies for NiF2 and CoF 2 The standard enthalpy of formation (Aygt for TiF2 and VF 2 is then obtained from Eq (1) and is listed in Table 34
Analogous considerations were applied to study AW for trivalent fluorides The data and results are preshysented in Table 35 and in Fig 35 The double-hump pattern of the data is evident in Fig 35 Subtraction of LFSE (given in Table 26) yields very satisfactory agreeshyment between theoretical and experimental lattice enthalpies of VF 3 and CrFj the agreement for TiF 3
(and for CoF 3 ) is less satisfactory As may be seen by the open circle below the curve in Fig 35 subtraction of LFSE from AHf overcorrects MnF 3 This is someshywhat surprising since MnF 3 with its 3d electronic configuration for Mn also has a azable JTE (Tabe 26) f the JTE were also subtracted the discrepancy from the smooth curve would be much greater In short the thermochemical data for MnF 3 are questionable
In estimating $HL and A for NiF 3 and CuF 3
(Table 35) only the LFSE was added to the spherically symmetrical values (ie smooth curve values) of ampHL In other words Eq (5) was applied without the empirishycal correction of 3 kcalmole
With regard to the A of the structural-metal fluoshyrides the theory as applied above suggests that there is little need to determine AVf for NiF 2 Moreover from the value of Afy of TiF 2 obtained in this study it is understandable why TiF 2 has never been prepared as a pure solid it can be easily shown that TiF 2 would readily disproportionate to TiF 3 and Ti However a more accurate experimental determination of A7 for TiFj would be desirable for both practical as well as theoretical reasons The same may be said for V F 2 VF 3 CrF2 CrF 3 FeF 2 and FeF 3
4 Gootint-Sak Chemistry A D Ketmers
41 CHEMISTRY OF SODIUM FLUOROBORATE
L Maya W R Cahill
The composition of the condensable fraction of the vapor piiase in equilibrium with molten fluoroborate can be defined by the system HuBF 4-HB0 2-H 20 as described in the previous report1 The work done durshying this report period was aimed at spectroscopic identishyfication of the molecular species present The B NMR as well as IR and Raman spectra of BF-2HjO FSFi(OHh- and of other intennediate compositions was obtained Dihydroxyfluoroboric acid (DHFBA) participates in exchange processes which could be desshycribed by the following equilibria
2HBF2(OH)2 = BF -H 2 0 + HBO
BFj-H 0+HBO = BF-2H 20 + HB0 2
The presence of HjBOj and HB02 was detected by 1R and Raman spectra and the pronounced broadening of the F and B NMR signals is an indication of exshychange processes The Raman spectrum of DHFBA indicates that this compound is a tetrahedral molecule Exchange processes were not detected for BF 3-2H 0 This compound appears to be stable at room tempera-twe The structural information derived from the Raman spectrum which identified BF 2H 2 0 as a
tetrahedral molecule agrees with the x-ray structural determination2 of this compound
Additional samples of condensate collected during the operation of the Coolant Salt Test Fanlity (CSTF) were analyzed (Table 41) Silicon is present because of attack on the glass trap used to collect the condensate Variations in the chemical composition of the samples can be interpreted as an indication that the condensed material is not a single molecular compound but rather a mixture formed by combination of the simpler gasshyeous species present gtn the system that is H 2 0 HF and BF The relatively high tritium content of these fractions should be noted Tritium is present in the system since some oi the Hastelloy N in the Icop was originally used in the MSRE The condensates show a tritium concentration factor of about I0 5 relative to the salt suggesting that fluoroborate coolant salt [NaBF4-NaF (92-8 mole )] may be sn effective means of concentrating and conveying tritium out of ikt system
Attempts were made to generate a condensable fracshytion in laboratory-scale experiments by heating oolant salt containing up to 200 ppm H as NaBFOH to 400degC in a closed system equipped with a coid finger The OH~ concentration in the salt decreased to 50 ppm and the composition of the condensate in a typical run was 532S H0BF 41483 (H0) 2SiF t anr 32^ free water found by difference The boron concentration in the condensed material did not reach as high a level as in
ORAL summer participant I L Maya MSR Program Semiannu Progr Rep Feb 28
VZ5 ORNL-5047p47 2 W B Barn and G B Carpenter Acta Ova 17 742
119641
TaMr 4 1 Analyses of CSTF trap coadeasttes
Sample Operation period Amount Chem
HOBF
ical compoMt ion Tritium content
imCifi Operation period Amount Chem
HOBF HBO SF
Tritium content imCifi
1 2 3 4
1972 11475 12475 31475 41575 41575 56lt75
Not avail 100 me
25 f 800 me
604 923 841 830
157 0
124 121
Not del 21 40 01
08 lo 30 r
57 34 06
Approximate amount Some of the material remained in the trap ^Difference(torn I0fr nH0 Given at a ranee Apparently more than OM simple was analysed for tritium content Data from A S Meyer and J M Dale Anal Chem [Mr An mi Pto0 Rep Jan 1974 ORNL-4930 p 28 The loop was not in operation between 12475 and 31475
41
42
the CSTF samples and there was considerable cor-bullosion Nevertheless these experiments showed a posshysible mechanism for the conversion of dissolved NaBFOH into a volatile fraction
An apparatus was assembled to measure he vapor d^rcity of BF i -2H G and related compounds at eleshyvated temperatures to determine the degree of dissociashytion of these materials This work tested the hypothesis that the condensable materials collected in the operashytion of the CSTF are completely dissociated at opershyating temperatures (+00~600C) and only combine to form more complex molecules in the colder parts of the system The procedure consists in measuring the presshysure developed in a closed system conuining a known amount of BF -2H 2 0 or DHFBA in order to establish the degree of dissociation according to the equilibrium described below
BF-2H 2 0 = BF+2HjO
At this time volumes in the apparatus have been detershymined and pressure determinations have been made using argon as a test gas Initial runs with BF 3 2H 2 0 indicate that this compound may be completely disshysociated at 400degC
Work on determining the oxide species present in molten fluoroborate is being continued and the survey1
of the system NaF NaBF4 BOj at 400 to 600degC has been extended to include IR and x-rav diffraction analyses in addition to physical and chemical observa-tiorii of the behavior of ^elected compositions The observations indicate that there are three main areas in the system
1 A region of compositions in which BFj is evolved This occurs with compositions having a deficiency in terms of equimolar ratios of NaF relative to the B 2Oj present
2 A region of compositions in which stable glasses are formed on cooling This corresponds to mixtures containing more than 33 mole B 2 Oj
3 A region in which crystalline phases and glasses coshyexist The tendency to form glasses on cooling decreases with decreasing B 2 0 j content
Usually coolant salt (NaBF4-NaF (92-8 mole )| contains relatively small amounts of oxide up to 1000 ppm and its composition lies within area 3 thus work has been directed toward characterizing the oxide species in this area At least two species were present one formed at the boundary of the glass area (high oxide content) and the other was NajBjFraquoOj which formed in compositions having NaFNaBF 4 B 2 0 mole ratios of 221 and 241 and was possibly present in
compositiors containing as little as 3 mole 7c BjOj Experiments at the 15 to 40 mole B Oj level approaching the coolant composition have been imshypeded by the relatively low sensitivity of IR and x-ray powder diffraction The difficulty with IR using the KBr pellet method arises from the fact that ~t thlaquoe oxide levels the only band not covered by BF 4~ absorptions is the one at 810 cm 1 This band has a relatively low absorptivity and it is common to NaBFOH NaiBzF0 N a B F t O and possibly other BOF compounds although the intensity and line shape are different for each compound A more certain IR identification can be made only when at least two topical bands can be identified (presently observable only at higher concentrations) as was the case in the identification of N a J B 3 F t O J at an oxide level correshysponding to 14 mole BJOJ Difficulties with x-ray diffraction arise from the low sensitivity of this techshynique coupled with the fact that the species have a tenshydency to form glasses Raman work on melts is being planned as the next step in this study
42 CORROSION OF STRUCTURAL ALLOYS BY FLUOROBORATES
S Cantor D E Heatherly B F Hitch
Alloys containing chromium in contact with molten NaBFlaquo-NaF would be expected to form a boride beshycause the reaction
(I + jr)Cr(c) + NaBF 4(d) + 2NaF(d)
= NaCrF(c)Cr xB(c) (I)
has a negative standad free-energy change (AG 0) At a temperature of 800degK ACj 0 o = - 1 0 kcal This value is based on an estimated standard free energy of formashytion (SGj) of NaCrF of -600 kcalmole In reaction (I) the exact value of x is unknown however AG of the more stable chromium borides (Cr2 B Cr5 Bj) is estishymated to be - 2 2 kcal per gram-atom of boron1 In nickel-base alloys reaction (I) may proceed more readily because of the probable exothermic nature of the reaction
CrTBfcgt +yNKalloy) = Cr(alloy) bull NiyBfc) (2)
3 O H KrikoriMl EstiirMion of HtJl Capacities and other Thermodynamic Properties of Refracsorv Borides UCRL-51043(1971)
4 O S GordkiN A S Dnbrovm O D Kokimkon and N ACherkovfun toys Chem 44431 (1972)
43
Assuming that AG of NiyB equals its enthalpy of formation AG for reaction (2) is about - 3 kcal per gram-atom of boron
An experiment to determine the extent of boride formation in the nickel-base alloys Hastelloy N (7 Cr) and Inconel 600 (15 Cr) has been in progress for sevshyeral months In this experiment mrtal specimens are equilibrated with NaBF4-NaF (92-8 mole ) at 640degC under an argon atmosphere and are periodically reshymoved washed free of salt using water and analyzed by spark-source mass spectrometry (SSMS) and less routinely by ion mkroprobe mass analysis (IMMA)-1
Analysts for boron on specimen surfaces by SSMS sugshygests some boride formation Hastelloy N specimens that had equilibrated for up to 129 days were found to contain 30 to 1000 ppm B Inconel 600 specimens conshytained 80 to 2000 ppm B Control specimens that had not been in contact with the molten salt showed 5 to 20 ppm when analyzed by SSMS Boron in Inconel 600 increased with equilibration time but with Hastelloy N the data were much more scattered and showed virshytually no time dependence
Several specimens analyzed by SSMS were also investishygated by IMMA Boron was present within the first few hundred monolayers of metal in inclusions also conshytaining sodium and fluorine in specimens of 2 Ti-modified Hastelloy N that had equilibrated for 72 days These contained 150 ppm B as determined by SSMS
5 Spark sowce mas specttomeuv and ion microprote mau analyss performed by die Analytical Chamstiy Dmson
The only plausible explanation seems to be that some NaBFlaquo remain on (or in) the metal surface despite the vashing (5 -10 nan in boiling water) intended to remove adhering traces of salt Some of the scatter in the boron analyses by SSMS is probably due to salt contamination of the metal surface Inconel 600 specishymens scanned by IMMA sholaquoed a similar pattern of surface inclusions contami^f B Na and F Unfortushynately IMMA does not provide quantitative analyses for these elements As yet the extent of boride formation cannot be quantified in either Hastelloy N or in Inconel 600 by a combination of SSMS and IMMA Probably however reactions (1) and (2) occur to a small extent boride is deposited at levels not greater than 500 ppm bullin Hastelloy N and not exceeding 1000 ppm on Incond 600 after four months of contact with molten NaBF44aF
IMMA was also used to obtain depth profiles of alloy constituents through about 5000 layers In control specimens elemental concentrations were uniform with depth far equilibrated Hastelloy N molybdenum was uniformly distributed throughout the depth explored but chrofiuuip and titanium concentrations increased linearly from the surface inward the iron concentration appeared to decrease slowly with depth Equilibrated Inconel 600 showed virtually no chromium in the fust 500 layers but chromium increased linearly in the next 4500 layers iron and nickel were uniform through the depth studied Thus IMMA indicates that chromium is selectively oxidized by NaBF -NaF (92-8 mole gt or by oxidants contained in this molten mixture
5 Development and Evaluation of Analytical Methods
A S Never
51 IN-LINE ANALYSIS OF MOLTEN MSBR FUEL
R F Apple D L Manning
B R Clark A S Mever
Corrosion test loops described previously have conshytinued operation with circulating reference fuel carrier salt LiF-BeF2ThF4 (72-16-12 mole ^ ) No additional loops hart been placed in operation during this reportshying period although several ire expected to begin opera-lion within the next few months
Measurements of the U-3 ratio in the forced conshyvection loop (FCL-2b) indicate a steady-state value of about 100 (Fig 51) This is somewhat lower2 than the
1 H E McCoy el al MSR Program Senumnu Progr Rep ug 31 1974 ORNL-50 I p 76
2 A S Meyn ec al VSt Program Semtcnnu Pro Rep Feb 28 1975 ORNL-5047 p 52
i MNL- om 75-1205
lt 1 1 1
3 V f mdash
amp amp amp
s 8 - i
bull bull
c I -J
m c
1 - i
-
2 bull bull
1
bull bull bull bull bull bull
raquo
bull bull bull
J _
bull bull
bull mdash
90 100 ELAMCO Tim
ISO 200 ltlaquobullraquoraquo)
apparent steady-state value obtained with the fluorid mixture LiF-BeF-ThF4 (68-20-12 mole 5gt indicating a less oxidizing melt The melt which started al a ratio of around 1000 reached this level via a redox process which presumably involves iactraquolaquoi ith the chromium in the walls of the vessel or in the specimens No atshytempts have yet been made to reoxidize the U3 in the melt by suitable additions of NiF or some other oxishydant It is interesting that the decrease to a steady-state value occurred after about 75 days ith a rapid deshycrease in the first 30 days Previous data from the expershyimental fuel showed2 a rather stable value near 10 for aoout 60 days until beryllium additions were made to force reduction of the U4
Some of oscillations in the data probably result from air contamination with subsequent oxidation when the loop was down This was most prominent with the experimental melt (68-20-12 mole S ) when the U43 ratio was substantially greater than the steady-state value reached at a later date
Ratios of U7U measured in the two thermal conshyvection loops NCL 21A and NCL 23 are summarized in Figs 5_2 and S3 respectively No unusual trend is apparent in the oxidation-state history of the fuel melt in NCL 21 A This loop was operated for about 240 days with Hasteiloy N corrosion specimens The curve shows a rather dramatic rise in the ratio whenever new specishymens are added This effect is attributed to additions of moisture and air which partially oxidize If3 A recover to lower ratios follows each increase in repetitive fashshyion
rj 1 t
OMl-Mt 79-OOSr 1 1 i
5 w i 1 V z
s Jr X
I bull 1
i 1 f
4 ^v bullw raquo bull
1
mdash bull
i i
bull bull
1 A- 1 100 190 ELAPSED TMfC
200 I )
290 300
FfcS1 Lmdash l gtFCL-2fc Fig 5J
NCL-m vmdashw
44
45
ORNL- DWG 75-12055 i i
1 i 1
2 bull 4 mdash 8s laquobull bullo
=3 i 3 bull copy
y i
bull bull bull bull I 1
i X bull bull bull
bull I I raquo IA raquo s s
bull bull bull bull bull bull
bull bull bull bulllt
laquo bull
I i 1 1
50 100 150 200 ELAPSED TIME (dors)
F4- 5-3- L LJ- ratios M rfcemal cowcctioa loop NCL-23
250
The U in the mdl in the Inconel 6CI loop NCL 23 wso aptdly retiuoed untS a V^iU ritio of around 40 was reached Since then the ratio has continued to decline reaching a relatively stable value near 5 The high level of chromium in the Inconcl 601 (23 wt lt) provides a sufficiently active reductant to reduce the U 4 more extensively than has been observed in Hastel-loy N loops therefore the greater U 3 concentration is not surprising
S2 TRITIUM ADDITION EXPERIMENTS IN THE COOLANT-SALT TECHNOLOGY FACUITY
R F Apple B R Clark A S Meyer
One major concern in the development of an MSBR is the release of tritium to the surroundings A potential method for limiting tritium release rates to acceptable levels involves trapping and removal of the tritium in I lie secondary coolant system This method must be tested before a complete understanding is possible of the manner by which tritium will be retained in an MSBR The present series of tritium addition experishyments involving sodium fluoroboraie will provide data on his method
The Coolant-Salt Technology Facility (CSTF) is being ltperated for testing the NaBF4-NaF eutectic mixture
with regard to its suitability as a oossible secondary coolant system In cooperation with loop engineers and technicians the Analytical Chemistry Group has been engaged in experiments to determine the fate and behavior of elemental tritium added directly to the cirshyculating salt to simulate at least in part the predicted transport o tritium into the coolant system via diffushysion through the primary heat exchanger This section describes the methodology and results of the first two experiments
About 80 mCi of tritium (diluted about 11000 with protium) was introduced into the salt stream over a period of about 11 hr beginning on July 17 Tritium concentrations were measured in the salt and the cover gas during the addition and for several days thereafter Salt samples were collected directly from the pump-bowl access port with a copper thimble covered with a copper frit One-gram samples of the cooled salt were diluted volumetrically and aliquots were mixed with a scintillation emulsion for beta counting
Cover-gas sampling has proven to be somewhat diffishycult At present a sidesfream is being sampled the diffishyculty arises from the passage of this stream through a nickel sampling line that is not completely inert chemishycally to cover-gas components Thus the amount of eleshymental tritium finally measured may not be an accurate
46
measure of tritium level within the loop gas system-More definitive experiments will require the use ot inert precious metals in the sampling system to remove doubt of chemical alteration of the cover-gas stream composishytion by the sampling system
The off-gis collection train consists of
1 a series of three water scrubber pretraps which serve to trap BFj and any other water-soluble compounds
2 a hot (400degC) copper oxide-tilted tube 3 a condensation trap to collect water formed in or
passing through the copper oxide 4 a liquid-nitrogen cold trap to remove the last trices
of water 5 a wet test meter to measure the volume of the iner
gas component of the cover gas that is helium
Results of the first injection experiment are summarized for the offgas (Table 51) and salt (TaWe 52)samples
Several days after operation had begun some liquid collected in the short glass section between the stopshycock used to divert the gas stream and the first trap in the analysis train The liquid was washed from the glass counted and found to contain about 60 jiCi of tritium This discovery clearly complicates the interpretation of previously collected samples since a large portion of total cover-gas tritium never reached the analysis train Furthermore no conclusion is possible regarding the chemical state of the tritium in the liquid The data suggest urn the concentration of elemental tritium
TabkSI TritimroMcM
iaCSTF
Tritium in ltas Time tpCimO
HOvluWe Fiemcnlai
17 1046 23 34 1305 07 12 1700 14 170 1 9 i i 1 93 2243 14 830
18 0100 32 420 0805 73 61 1000 44 71
19 1037 790 62 21 0905 1800 13
1325 50 13 22 0925 55 58 23 1303 85 29 24 1000 300 22 25 1315 340 26 28 1245 10 27
TaMrS2 TtitmmcoatcM mslaquot sMf tn rflrtfiol w i l i i jjiiwon mCSTF
Date July
Simple No
Time Tritium inCi (l
1 45 IKW 12 46 I3MS raquo 47 1512 35 4 1718 51 49 1930 9 j 50 2145 73 51 2321 H 2
1 52 1102 32 53 1912 20
laquo 54 9130 15 SMV 0952 75
21 55 1132 16 bullraquo2 56 1400 16 23 57 1330 20
increased in both the cover-gas and salt samples when the liquid was washed out between sampling periods I July 23-25)
A second tritium addition was made August 5 During this experiment no changes were made in the sampling apparatus but that region of the sampling train (desshycribed above) where liquid had been accumulating v as washed with each sample collection and counted sepashyrately The tritium found there was added to the water-soluble tritium measured in the pretraps Data for this experiment are summarized in Tables 53 and 54
An exhaustive analysis of the analytical and sampling aspects of these data is not warranted at this time since several variables which affect the addition sampling and the tritium losses have not yet been established A general discussion on the oehavior of tritium in the CSTF is given elsewhere1 The preliminary data are sufshyficiently encouraging to merit a more extensive investishygation into the extent and mechanism of tritium intershyaction with sal and cover-gas components Plans are now under way to monitor the tritium diffusion through a portion of the loop wall and to measure the level of active protons in the salt during addition of tritium A more intricate bull over-gas sampling device (a probe designed for the sart monitoring vessel or salt sample port) is being considered and may be fabricated if no simpler solution to the gas sampling problems can be found
3 Reference Sect 112 thn report
47
TaUeS3 Jiitmtm content in cover-gas amahs after jtvoad tritium aMinoa
mCSTF
Tricium m ja D l l e rime laquopCimll
(AlKWM) HOvi luhk HcmenuJ
5 0730 96 o5 ltmraquo HO 2 2 1130 22oo 10 1330 5JWgt 20 1530 7500 27 1830 13000 34 1920 13000 39 2100 12000 40 2315 9300 39
6 laquoP3n 9300 2 I I mi ltraquo) 16 1500 6500 i4 2000 4700 10
7 0940 3300 68 1415 2400 49
O93o ltraquo00 34 9 1450 1600 52 to W40 1300 2 1 1230 900 2 J 12 1010 570 11 13 1010 23o 0 15 inoo 1X2 lO llaquo iraquo935 76 05 21 1010 73 o j
TaMr 54 Tribmn content m sak s a f k i after moan H i r i mdash aaditioa m CSTT
Dale Sample Trunin iAapnU No m lad-e l
4 5 1313 nraquo 5 59 (1954 90
60 1145 21 61 1350 36 62 IS4ft 52 A3 IX4X 7 | 64 1932 6ft 65 2125 71 66 2335 50
6 67 lift in 30 6ft 157 19 A9 2 lraquo 16
7 To IOI4 9 5 71 152 ft 1
T 1 lolft 36 9 73 0916 4 2 I I 74 124ft 39 12 75 1035 14 13 76 I04K ^ 1
15 77 IOIO 14 I I I 7raquo IOIO 07 21 SMV IOA l3fW o5
5 3 ELECTOOANALYT1CAL STUDIES OF IRON II) IN MOLTEN LiF-BeFj-TkFlaquo
(72-16-12 MOLE 9tgt
D L Manning G Mamantov
Electroanalytical studies in molten fluorides have particular importance tor possible use as in-line analytishycal methods for molten-salt reactor streams Irani II) is a corrosion product present in molten-sIi reactor fuels We have previously carried out electrochemical s tud ies of i r on ( l l ) in molten LiF-NaF-KF ( 4 6 5 - 1 1 - 5 - 4 2 0 mole L iF -BeF 2 -Z rF 4
(696-254-50 mole ) and NaBFlaquo-NaF (92-8 mole ) Since the fuel solvent for the MSBR is a thorium-containing salt LiF-BeF ThF 4 (72-16-12 mole )it is of interest to conduct vortasnmetnc and chronopotenti-ometric studies of irondl) in this fuel solvent To detershymine concentration andor diffusion coefficients by linear sweep voliammetry it is necessary to know whether the product of the electrochemical reaction is soluble or insoluble The measurements discussed bdow were dace with this purpose in mind
A volummogram showing the reduction of ironOU Fe2 -raquo Fe at a gold electrode is shown in Fig 54 The circles represent the theoretical shape based on current functions tabulated by Nicholson and Sham for reversible wave where both the oxidized and reduced forms of the electroacthre species are soluble Thus even though Fe2 is reduced to the metal at gold the electrode reaction very closely approximates the soluble-product case apparently through the forrmtion of iron-gold surface alloys Further evidence that the Fe3 - Fe electrode reaction at gold conforms to the soluble product case is illustrated by the chronopotenti-ograms in Fig 55 The ratio of the forward to reverse transition limes ir^r) compares favorably with the
4 D L Mannmc Votcaninernx- Sradaroif Iron m Molten Lif-Nar--Kr fVermwwj Chen 6 2 2 7 i | 9 6 3 l
5 D I Mannine and G Manunfti X j p d San Voium-metric jnd CrirraquonnjgtotentKgtroeirraquo Sludirt igtf Iron in Molten H w r e k W tleclmtntl Oirm 7102 H964raquo
6 I I W Jenknu D I Manmae and O MamantoT Flec-irnde fotentiaU of Several Redlaquo Conple in Mollcn Hno-rnfeO Nmntchrm Sgth 1171 S3 119701
7 f R Clayton it HeciiochemK-jJ Slwbe in Molten Hnoride and Fraorntmrawv doctoral dtunalnm Imvenm of Tenncvee December 197) p ft2
ft A S Meyer et j l MSft Program WniMwn rop Rep Aug M 9 T 4 ORNl-laquo72Xp 44
9 R S Nicholson and I Sham Theory of Stationary FKtrode foiarocraphy J Oitm 3 7 0 7 I | 9 O I
48
QWNL-PWG 75-11275
I I I I I I I 150 tOO 5 0 0 - 5 0 -WO -150
POTENTIAL mV
Fy- 54 Stationary electrode watamumapam for e refacshytion of r V af gt faM electrode bull Broken UF-ueF-TnF Po-lentil axis B ltf - poundbullraquo-- Solid line is experimental Circles are theoretical dupe lor soluble product Iron) III concentration 0027 f electrode area 025 cm s lemperature 650 C
theoretical value of 3 (ret 10) for the soluble case which again points to the formation of surface alloys
The reduction of Fe2 at a pyrolytic graphite elecshytrode is illustrated by the vultammogram in Fig 56 and the chronopotentiograms shown in Fig 57 For the reversible deposition of an insoluble substance where n = 2 the voltammetrk Ep - pound p I = 303 mV at 650degC (ref II ) is in good agreement with the experimental value The chrooopotentiometric ratio (zyrr) is approxshyimately unity which also h indicative that Fe2 is reduced to metallic iron without any apparent interacshytion with the pyrotytic graphite and that all the iron is stripped from the electrode upon current reversal Therefore iron appears to be reversibly reduced to a soluble form at gold and to an insoluble material at pyrolytic graphite Thus the effect of electrode subshystrate on an electrochemical reaction is illustrated by this example
Chronopotentiograms for the reduction of Fe2 at an iridium electrode at 518 and 60DdegC are shown in Fig 5 8 The ratio at S I8degC is approximately unity and is 3 at 600 a C which is evidence that Fe1 reduction at iridium approximates the insoluble-species case (as with pyrotytk graphite) at SI8degC and the soluble-product case (as with gold) at 600degC This change in reduction behavior with temperature was not as pronounced at gold or at pyrolytic graphite
10 W H RimjnMn Oirowopoecmwiweiiic Transition Times and The Interpretation^W Chem 321514 (l0gt
11 C MwuMm D L Manm and J M Dale Reversshyible Drpnsitrxi of Metal on SoM Electrode by Voflammetry wnb Linearly Vary in Potential tlrctntml Ckem 9 253 tl9raquo5gt
The chronopotentiometric transition time r for an ekctroactiw species is given by the Sand equation 2
Average diffusion coefficients oi Fe2 in this melt evalushyated from the chronopotemiometric measurements by means of the Sand equation are approximately 42 X 1 0 80 X 10 and 15 X I0 5 o n 2 sec at 5IX 600 and 7O0degC respectively
54 VOLTAMMETRIC STUDIES OF TELLURIUM IN MOLTEN UF BeFThF 4
(72-16-12 MOLE )
D L Manning A S Meyer G Mamantov
Tellurium occurs in nuclear reactors as a fission prodshyuct and results in shallow intergranular cracking in structural metals and alloys i It is of interest to charshyacterize this substance electrodiemicaliy and ascertain the feasibility of in situ measurements by eiectroana-lytical means We previously14 carried out preliminary polarization measurements at a small tellurmin poc1
electrode in molten LiF-BeFj-ZrF to estaampbh (he potentials at which tellurium is oxidized and reduced in the molten fluoride environment These preliminary observations indicated that the electrode reactions are complex
For tellurium screening studies J R Reiser of the Metals and Ceramics Division fabricated an experishymental cell equipped with viewing ports and electrode ports for studying the stability of lithium teUuride LijTe in molten LiF-BeF-ThF4 The Li2Te was added as pellets following which voUammograms were reshycorded at gold and iridium electrodes
As LsTe was added to the melt the voliammograms became com4ex and are not yet completely undershystood For clarity pertinent observations at the iridium and gold electrodes are tabulated separately
1 Upon adding one 35-mg pellet of Li 2Te a reducshytion wave observed at 09 V vs the It quasueferencc electrode (ORE) disappeared- fhis wave is not yet
12 Pan Drlahay p 179 IT in Srw hturumenuH Mrlkodt m Eltcmxhrmotry htterscience New York 1964
I J H F McCoy Maiernh tor Salt-Tontammt Veswlsand Pipmt The Dtvrktpmtni mtd Vlaquoftn of Mollrn-Sali Rnclon OftNMH|2ll-ebnary 1975raquop 207
14 A S Meyer el j | JW hnmm Stmmmmi Prop Rrp Aug SI 1974 ORNL-5011 p 42
49 ORL-0G 7S-M277
OWEVT TiME CURRENT TIME n l tslaquocdraquo) (mA) (stcdw)
5 J Cyclic ibroouyofcplimi mdash i for w wountioa of bulloa j l l ) at a f o M efcinuiat Foraufciy of troMllt X15ttecti ode jrcj
identined The pellets did not melt or dissolve immedishyately Relics ot the pellets could be seen on the surface tor several days The windows of the viewpcris became coated with a bluish-fray deposit after a few days making viewing of the melt impossible The bluish-pay deposit is believed to be tellurium metal Tim indicates that tellurium species added as L i Te are not stable in the melt
2 Voltammograms recorded in molten LiF-BeF -ThFlaquo after additions ot Li Te did not reveal any waves that could be attributed to soluble dectroactive tellushyrium species Chemical analysis indicated lt5 ppm Te in the melt
3 Abo at an indium electrode a reduction wave was observed at 045 V vs the Ir ORE which was reasonshyably well defined at a scan rate of 002 V sec This wave is due to Cr J reduction the wave height increased upon adding CrF 2 but did not change upon adding LijTe At our normal scan rate of 01 V sec the wave was not well defined which explains in part why it was not positively identified on background scans that are norshymally recorded at 01 V sec
4 Voitammetrk waves indicative of leilunde firms on a gold electrode were observed However these waves disappeared after adding CrFj to the melt The volt-ammogramlt recorded at gold foflowmg the L i 2 Te addishytions became complex and the electrode reactions are not yet resolved
Additional volrammeirr measurements are planned whereby the supposedly more soluble and stable LtTe species will be added to the fuel melt
igt 2$ c m 2 temperature M W C potential io le wilts s Ir QRF
ORNL-DWG75-11276
l _ _ J I I 1 bull 0025 0 -0025 POTENTIAL V vs U ORE
fSA Statpmry laquofctWodc to l lmdashuupaw for IW rwJt-timi of imKl l ) at a bullyrorytic gray laquonlaquouut InwfoMe prodshyuct j i 650 ( ibrnretH-jl Kp hbdquoi - 05 mV me-i-uired 3 0 mV InHMlll ctgtiraquocenirjiHgtn n02 electrode jrea 01 o n
so
C---+C S -raquoTS
TMpound
F-f57 Cycfc Hraquoi-o-i--uli bull gt bull y mdash l fat HJC rofactioti of mottlU M raquo etcmgt4e area 01 cm 1 -cmr-mare 650C potcnlbi - o k tuli VI Ir URF
-TIME
FomuiilT ot irondh iraquoiraquo
vt
w i l l
Ffc SJ Cydm ctmomtfottmtia^mm for r jrra n2 a n 1 po-rnlnl laquoale raquonltlaquo v Ir QRF
ft- bull v -
r of MMdl ) at i Formality of -rolaquo(llgt OfMVrfcctr-i-Jr
Part 3 Materials Development H fe McCoy
The main thrust of the mateiials program is the develshyopment of a structural material for (he MSBR primary ciicuit which has adequate resistance to embrittlemeni by neutron irradmion and (o shallow intergranular attack by fission product penetration A modified Hasteiloy N conoining 2^ Ti has good resistance to irradiation embnukment however it remains to be shown that the alloy has sufficient resistance to shallow intergranular cracking Numerous laboratory tests are in progress (o answer (his important question It may be necessary 10 further modify (he alloy with rare-earth niobium or higher chromium additions (o impait heller resistance (gt shallow intergranular cracking
Laboratory programs (o study Hasteiloy N salt tellurium interactions are being established including the development of methods for exposing (est mat era Is under simulated reactor operating conditions Surface-analysis capabilities have oeen improved so that the reaction products in (he affected grain boundaries can be identified
The procurement of products from two commercial hea(s 1000 and 10000 lb I of 2^ Ti modified Hasielloy N continued All products except seamless
tubing were received and much experience was gained in (he fabrication of She new alloy The products will be used in all phases of (he materials program
The work on chemical processing materials is concenshytrated on graphite Capsule tests are in progress to study possible ch-mical interactions between graphite and bismuth-lithium solutions and to evaluate (he mechanishycal intrusion of these solutions into the graphite Since (he solubility of graphite in bismuth-lithium solutions appears to increase with increasing lithium concentrashytion a molybdenum thermal-convection loop that conshytained graphite specimens was run to study mass transshyfer in a Bi 25 Li solution
Some of the effort during this reporting period was expended in reestablishing test facilities Four thermal-convection loops are in operation in the new loop facility which will accommodate at least ten loops The mechanical properly and general test facility is partially operational but numerous test fixtures remain to be assembled and tests started An air lock has been added to the general test facility to make it more functional and plans were developed partially for further expanshysion of the faclity
51
(x Development of Modifk-d Ha^tclkn N H t McCoy
The purpose of this program is the development of metallic structural material)) for an MSBR The current emphasis is on the development of a material for the primary circuit which is the must important problem at present The material for the primary- circuit will be exposed to a modest thermal-neutron flux and to fuel salt that contains fission products It is believed that a modification ot standard Hasteiloy N will be a satisfacshytory material for this application An alloy that contains y1 Ti appears to adequately resist irradiation embrittle-ment but it remains to be demonstrated that the alloy satisfactorily resists shallow intergranuiar attack by the fission product tellurium Small additions of niobium and rare earths (eg cerium lanthanum) to the alloy abo improve the resistance to shallow intergranuiar cracking and likely will not reduce the beneficial effect of titanium in reducing neutron embrittlement Increasshying the chromium concentration from the present 7T to a value in the range of 12 to 15 may also be beneficial in preventing shallow intergranuiar attack Currently factors associated with production of the 2T Ti modified alloy in commercial quantities are being studied while smaller be-ts raquoe being nude o( Hasteiloy N containing both 2 r Ti and additions of niobium and rare earths These materials are being evaluated in several ways
Two large heats one 10000 lb and the other 8000 lb of the ya Ti modified alloy have been melted by a commercial vendor Product shapes including plate bar and wire have been obtained for use in several areas of the alloy development program Tubing is currently being produced by two independent routes The various product forms from the two large heats are being used to fabricate the salt-contacting portions of two forced-circulation loops
Laboratory methods for studying Hasteiloy N salt tellurium reactions are under development Methods must be developed for exposing candidate structural materials to simulated reactor operating conditions Tests are being run in which specimens are exposed at 700V to the low partial pressure of tellurium vapor in equilibrium with tellurium metal at J00C Other tests involve metal idlundes thai are either added to salt or scaled in cvjcualed quart vus lo provide a source of tellurium Several experimental alloys have been exshyposed lo tellurium and Die extent of inlergranular cMltking was evaluated meiallograpliically hssenli^l In tins prltgram jrc attentate technique for identifying
and characterizing the reaction products Several methods for the analysis of surface layers are under development
Materials that are found to resist shallow intcrcranuiai cracking in laboratory tests will he exposed laquobull fissioning salt in the Oak Ridge Research Reactor TeGen fueled-capsule series Three materials (standard llastelloy Inconel 601 and type 304 stainless steel) were exposed in this manner during the first TeGen experiment and their cracking tendencies closely parallel those noted in laboratory tests in which these materials were exposed to tellurium vapor Fuel pins for a second experiment have been filled with salt containing gt J U and will be irradiated in the i a future
61 DEVELOPMENT OF A MOLTEN-SALT TEST FACILITY
H E McCoy K W Boling B McNabb T K Roche J C Feltner
When the MSRP was terminated early in 1gt73 most of the equipment was reassigned to active programs When the MSRP was reactivated a year later the conshystruction and installation of new equipment were necesshysary before testing could begin Balding 2011 acquired by moving the occupants into a siraquoaller building had been used as a mechanical testing area about 12 years previously and was already equipped with emergency power and air conditioning However numengtus imshyprovements ~n the building were necessary in addition to lb acquisition and placement of new equipment Although all of the equipment is not operational this report will describe the status of the facility
The building is a two-story structure with mnninal dimensions of 50 X 50 It The first floor is quite thick and more suitable for -mourning vibration-sensiiive test equipment The second floor is of lighter capacity and is more useful for offices and supoort activities There are Iwo stairways leadmg lo the second floor hut all heavy-items must he brought up hv an overhead crane which extends from the west side of the building The west wall had deteriorated and large doors leading into llie first-floor experimental area made close temperature control almost impossible An air lock having the dimensions 10 X W ft was added lo the west side of the building which greatly increased the buildings usefulshyness for experimental work An inoperabk emerge- puwei geneialor located in a small building on the cast
52
5
side or Building 2011 Mas removed and the space renovated to provide a small shop area
Figure 61 is a photograph of the west side of Building 2011 The air lock which was added is visible on the left-lurid side The crane lor transposing materials to the second f raquo)t is alsigt shown Figure b2 is a view of tllaquoe north side (ias storage racks the new emergency power generator and tie small shop area I left sulci are evident
Figure raquo slows the equipment layout tor the first floor Some of the equipment in the southwest owne is used by the Analytical Chemistry Division lor detershymining the concentration of oxygen in liquid-metal samples A neutron generator is located beneath the salt storage ar a and is used for oxide activation analyses This analytical capability is quite unique and will likely be maintained The 14 lever-arm creep machines on the north side aie for testing in an air environment the 8 machines in ihe next row are for testing in a sail envishyronment the Ji machines in the next row are lor testing bulln an air envirorment Five strain cycle machines are located in the southeast corner and will operate with
test specimens in j salt enviroiiVrctii Ihe temperature and strain readout equipment is centrally located Sail storage tjclitie and salt charging equipment are used ut conjunctii-n with he tests operating in salt environshyment S
The equipment layout on the second floor is shown m Fig o4 Six deui-Ioad creep machines for testing in an air environment are located on the south wall- The tube-hurst equipment is only partially instiled and lis installation is not considered a high-prioritv item Tie annealing facility consists of en furnaces having vartcux temperature and envingtnmental capabilities A separate laboratory in the northwest corner is used for experishyments involving tellurium llasieiloy N interaciiiws The other facilities on the second floor include offices a data storage and processing area an instrument repair shop and general storage
A view of iome of the 22 lever-arm creep machines for testing in an JH ermionmeni is shown tn l-ig t o and a cl-raquoeup is shmn in Fig traquofraquo All of these machines are in operation The control cabinet shown in Fig istraquo contains tlie insirunteKistion for two creep machine-
Photo 22SC-7S
yen 61 Mollrft-SjH Teraquol Faculty (RmMiof 2011) (mm Ihc wta ale The newly tiHUtrihled Jit lock bulllaquo mi the left
54
iJf JhZ
^bullyr^J^f1
Fifc J Matae-S TMI Ficttljr (Baliinj 2911) fjoraquo the monk ate Feature of interei include the hop area on he tt~ left the emenBencv pronator on the kft o s Morale rack in the center and the newly constructed air lock on the ri$h
iraquo now
I if(raquoraquo Kquipmcm layout for the fir floor of BudJinf ifll I
55
Fig fc4 EqnpncM Iqroat for Ifce Miomd Onor of IwMMg 2011
The frame is of welded steel construction The levei arms have two sets of knife-edge pivots vgt that the weight on the back of the arm is multiplied by factors of 6 or 12 The pull rods and cxlcnsometcrs are curshyrently arranged for testing small specimens having gage dimensions 1 in long by lA in in diameter Pull rods and cxtcnsomctcrs lor larger specimens required for code testing) were also fabricated and can be used in the same machines
The specimen deformation can he determined by the dial gage or by a transducer which measures the deflecshytion of the dial gage shaft This transducer signal is conshyverted to a dc signal by the instrumentation in the bottom of the control cabinet cm the right (Fig 66) and is printed at another location The electronic circuit will also accommodate averaging transducers which will be used on more precise code work The instrumentashytion in the bottom of the control cabinet also has a module for measuring load from a load cell (not shown) which Tils in the bottom on (he creep machine The specimen is heated by a resistance-wound furnace
having a maximum Icmpcraturc capability of I200C The temperature is measured by up to four Chromel-Alumd plusmni accuracy) thermocouples treated at various positions on the ipcimcn gage kngth The signal fron one of these thermocouples is used by the Leeds and Northrup type KO proportioning controller to control the furnace temperature Switches within this unit activate an alarm shown in the upper left coiner of the control cabinet (Fig 66) if the temperature varies more than plusmn6degC from the control temperature This alarm unit activates a local light and bell alarm as well as causing an alarm t gt sound in the Shift Operations Office A second thermocouple is tied to an over temperature monitor (lower left side of control cabinet in Fig 66) This monitor is set 10 to I5degC above the control icmp-rraturc arid will interrupt power to the furnace The monitor must be reset manually The furnace is powered by a solid-slate power supply deshysigned by T Hulton of the Instrumentation and Conshytrols Division The unit incorporates a digital Variac which allows power settings of 0 10 25 SO 75 and
56
FlaquofcS i t f
100 of line voltage Power is pulsed through the unit as called for by the Leeds and Northrop controller
The six dead-load creep machines on the second floor are quite similar to the lever-arm creep machines just described As shown in Fig 6 7 these machines r e not in operation but the construction work is com| iete Since the load is applied directly to the bottom of the specimen the equipment is limited to specimen stresses of about 20000 psi However the frames can be conshyverted to the lever-arm type
Two salt environment creep machines are shown in Fig 68 The frames and control instrumentation are the same as for the air environment machines shown in Fig 66 The primary modification is a stress unit which can be immersed in salt Four load-bearing rods run from the bottom of the specimen to a flange near the top of the frame A rod from the lever arm passes through a seal in the flange to the top of the specimen Thus weights placed on the back of the lever arm place the specimen under tensile stress with the pulling force being transferred back to the flange No rods protrude
far below the bottom of the specimen and a salt conshytainer can easily slip over the stress unit This container seals against the underside of the flange Extensometer rods for measuring the strain pass through seals in the flange and strain can either be measured by a dial gage or a transducer A 4-rn-diam furnace fits over the salt container There arc several openings through the flange into the container for gas lirtes and ball valves for elecshytrochemical probes and for making additions to the salt Figure 6deg shows the salt-creep machine which is in sershyvice The salt raquoas transferred into the pot on the right in the salt preparation facility at Y-12 The transfer pot was placed in a furnace after which the transfer pot and the receiver vessel were heated to about 600degC before the salt was transferred by applying argon pressure to the transfer pot The temperature was stabilized in the creep chamber and a strejs was applied to the test specshyimen
One of the five strain-cycle units is shown in Fig 610 The test specimen is a l-in-OD tube with a reshyduced gage section having a length of I in The tube is
57
Flaquo 6A CkMtmp of two Mr-
welded in place and stressed by a rod which extends from the bottom of the specimen to a piston above the specimen The piston s moved by applying air pressure to either side resulting in a tensile or compressive force on the specimen The specimen assembly is immersed in salt while it is being stressed Extensomeier rods extend through the top flange to measure the strain These rods move transducers whose signals are recorded on the bottom instrument Switches inside the recorder can be
adjusted to change the stress from tensile to compresshysive when the strain reaches certain values The test can also be controlled on a time basis and the strain reshycorded Other modes of control are also possible This type of test is to study the rate of crack propagation through thin-walled tubes of varying composition in the presence of tellurium Installation of the equipment has been completed and test specimens are welded in place The tests will be started as manpower becomes avail-
raquo
ask Thear mdashaAntv war be ased for aftojr and ame precise work w be done oa MTS e war arm to be procared at a later dale
The anai jau colectioa station h oa fLe first lloor (Fig 611raquo The apper part of the cabiaet OR die left cuMtaatt snitches a aiaiial readoat aad a snaje poiat recorder lor leraperatnres from avow one-third of dK machiaes- The haak of Mriicbes ia the top of da rajfct-haad cabinet is for tetecrinc siraia rawerraquo for each
The sna-i tcadaajs faaa each auduae arc priated oat oa oae of the andtipoiai recorders A data
M I is located m the aaodfc of the right-I cabiaet Has rnsmMKM ltai print oat 100 points
oa dK designated Ireqneacy (asaaly I br) This is snf-fcieat capacity to print oat oae teaaperaiare aad one
for each piece of eqai|aarnt Two orjer bulleasnriag stations are located elsewhere on
dK first floor
Ffct7 General
59
The annealing arez sun the second floor I Fig 612) The two furnaces on the lower level have environmental control and are used for short-term anneals Eight other furnaces are used for long-term anneals hi which the samples are encapsnlated
Figure 613 shows a typical area in tne second-floor laboratory wed for tdurtum-HasteBoy N studies The
equipwunt includes a quartz encapsulation apparatus special gradient furnaces for annealing the capsules equipment for measunng gas-metal reaction rates and a general-purpose hood
The ttthe-burst equipment boa die second floor (Fig 614) There are nine test stations with each station
four test |
Fin 68 Close-up of two bullut-eiwuuinwtnt lever-arm creep machines The salt chamber on the left-hand machine seals apinst the horizontal flange and the furnace n raised a proportionate distance The temperature control and strain-measurement instrumentashytion are shown on both sides of the creep machines
60
Ffe 69 Lever-arm jd l imnunmiiit creep NMCJMMS in operation The ult chamber and furnace have been raised calt as transferred by argon pressure from the vessel on the right into the test chamber The cabinet on the left contains switching and temperature readout instrumentation for several creep machines
61
FlaquoIO ChwMip of a a l l ltngtJKinmml strain cycle machine M l amocMni intfnjmvntation The ieraquoi specimen is a l-m-diam lube welded on I he bottom I a rod and un ihe lop to a heavy-walled lube The rod passes through the lube and alicrnaling tensile and compressive stresses are impigtsed on the specimen by ihe actuator (piston-cylinder combination) The instrumentation is used to control and record the sires strain-time history
bull2
F g 61 I The cabmct on Ike left is one of smraf tartowt stations for limptnmn Chrontd-Alumel sensors from seYeral creep machines arc ran to this cabinet The switches make it possible to read each thermocouple individually on the digital unit at tlie lop of the cabinet One point at a lime can be recorded on the Azar recorder The cabinet on the right contains a data logging unit for recording strain and temperature on all the machines on the first door The three recorders in the bottoms of the two cabinets record strain data from a l machines
a
fit- 612 tkotopajk of hcsMltsaag facfvty The two lower furnaces have com roikd argon environments Fighl other furnaces (al noi visible) have air environments and are used for long-lime anneals
64
Fig raquo13- Typical vie of geaoat-aeaaot used to dean salt from jpuiawai tested in a l t amroameati
ettl reactroas The hood on the left is
rraquoraquoiraquo wraquo-raquo
F|g 614 General view of tube-burst testing eqaipment asai lo stress tabular spec ant ni by internal pre ware The front paneli contain only (he pressure-related equipment The furnaces where the test specimens ate located and their associated control instrumentation are behind the pressure panels
65
by a pump with a wear pressure of 14400 pa The pump aad the ass-xiated reservoir cylinders have beea approved for opcratioa aad the iaawaaal test suborn w2l be pat irt semcr oa c ow-pnonty basis
Iiiaatdun efiptens wtfJ be placed oa geinaf a l equipment iato operatioa Longer-term objectives war iadade prucaremeat aad iastaaatioa of an MTS fatigue machine aad possible expansion of the fast floor to accooaaodaie additioaal creep machines
t J PROOJKEMENT AND FAMUCATION OF EXHHMENTAL ALLOYS
T K Roche R E McDonald B McNabb J C Fehaer
bullUI hadwit iaaHeatsafraquo Ti M I T I I I M H I I J N
One of the more promising alloys at present for the primary circuit of an MSBR is 25 Ti modified Hasidloy N Progress has been made in the scale-up of this alloy with the production of two large heats one 10000 lb and the other 8000 lb by a commercial vendor The analysis of the heats was reported preshyviously These heals were used to establish processing parameters for producing plate bar and wire and more recently emphasis has been placed on processing seamshyless tubing Mill products from these heats are being tesed in the general alloy development program and used in the construction of two forced-circulation loops for studying the compatibility of the alloy with fuel salt
As reported previously several fabrication problems were encountered with the first heat (heat 2810-4-7901 or 74-901 10000 lb) in that it was prone to cracking during hot-working operations particularly during hot rolling of the plate However with the aid of Glcebli evaluation tests which defined the hot-working temperashyture range of the heat to be between 1090 and I I77degC plate products were successfully rolled A second prob-leri was the susceptibility of the heat to cracking during the annealing treatment following cold drawing in the production of bar and wire products This problem was partially solved by cither flexing the drawn product in straightening equipment prior to aiiiltjHijat 1 7degC or by lowering the intermediate annealing temperature to nidegc
Because a considerable amount of the first heat wis consumed in establishing processing parameters a
I T K Roche B McNabb and I C FeltrwrMSK Proshygram Semmrmu Pmgr Rep Feb 2 1975 ORNL-5047 pp 60 63
second heal was prodaced (hat 8918-5-7421 or 7S42I 8000 lb) for coavcrsioa to tatang bar and wire The bot-forgaag behavior of das heat was qaite good as confirmed by Cfeebie data which showed a very broad bot-workmg temperature range of 930 to 12600 Approximately one-half of das heat was forged and tamed to 4 Jna-diara bar for coaversion to seamshyless tubmg by the vendor Akoa forged bar 4 X 4 X 6 0 in was produced for conversion so tabiag by an altershynate route The balance of draquoe heat was convened to the folounac products which bat been received o-m-diam bar (630 lb) 05-ai-diaai bar (292 ft) 0J12-in-disn bar (996 ft) 0125-av-diaai wire (405 b) and 0-094-in-diam wire (338 lb)
For making products in the range ^-ia-diam bar through -in--diam wire forged bar was hot roBed to about I-ia-diam bar and an attempt was nude to conshyvert this material by cold drawing to final sizes with intermediate annealing treatments This routing proved satisfactory unti a H^meter of 0J95 in was reached but annealing cracks as experienced with heat 74-901 were encountered to some degree during processing of the 03l2-tn-diam bar and the wire products For example during a run involving about 850 lb of stock about 2 of the product was lost due to cracking during annealing after the material was drawn from 0J95 in in diameter to 0 J i 2 in in diameter The bar was mechanishycally flexed prior to annealing a technique used to minimize cracking in material from the first production heat of the alloy (heat 74-901) The annealing cracks were observed to run parallel to the longitudinal axis of the bar Examination of a transverse section of the cracked 0Jl2-in-diam stock showed that the cracks were intergranular in nature and up to 0065 in deep in the section examined (Fig 615)
It has been possible to reproduce the annealing crack phenomenon on a laboratory scale Samples of 05-in-d am bar of each of the two production heats were coiJ drawn lo 0395 in in diameter (37 reducshytion) and annealed at I I77degC Heat 74-901 developed longitudinal cracks heat 75-421 did not These results are consistent with the vendors observation that heat 74-901 is more susceptible to the cracking problem Since the cracking can be reproduced or a laboratory scale it may be possible to more fully characterize the problem and define fabrication parameters necessary for its prevention
Of the two routes being pursued for the procurement of seamless tubing one by the commercial vendor inshyvolves trepanning forged and turned bar slock to45-in OD X 05-in wall cold tube reducing (or pilgering) the material in three steps to 20-in OD X 0187-ir wall
66
m
o p A
-O o_ b
o x t o 1 yraquo2
o o-
8-o
yen $ H m d i raquo cocks iraquo ttJU-aL-MMi bat of 2raquo T t - a o M M KasMftty N (hut 75-421) Bar was coM drawn 37- and ameafcd a( I065C Ftdicd with (dyccm rrpa 50x
followed by cold drawing to final sues of 10- 075- 05- and 0J77-in OD X OJ035- to OX)72-in wall This route for tubing production depends upon the efforts of two other vendors one for trepanning the bar and the other for drawing to tlnal sizes The trepanning operashytion has been competed and resulted in six tube holshylows each approximately 6 ft long Each of these pieces was processed through the first tube reducing pass to a 375-in OD X OJ75-in wall (3675 reduction) with no difficulty From this point work was confined to one tube hollow to determine its response to in-process annealing at I I 2 I degC and water quenching followed by further tube reduction Annealing of the hollow beshytween each tube reducing operation was preceded by the annealing of a sample which was then liquid penetrant inspected to determine any evidence of crackshying With this procedure the hollow was taken through the remaining two tube reducing steps and three annealshying treatments with no major problems A few shallow surface flaws did develop but these were readily condishytioned from the product Therefore on hand at present is approximately 24 ft of 20-in-OD X OI87-in-wall stock which will be scheduled with the redraw vendor for processing to final sizes The lube reduction of the remaining five hollows will also proceed
The second route for obtaining seamless tubing inshyvolves hot extrusion of tube shells at ORNL followed by cold drawing to size by an outside source Starting stock was the forged bar of the alloy 4 X 4 X 60 in (Fig 616) The bar was machined into six billets each of which measured 3deg50 in in OD by approximately 95 in long and had a 45 tapered nose for extrusion out of a 4060-in-diam press container through a conical die Two of the billets were drilled 0812 in in ID and four were drilled 10 in in ID to accommodate a mandrel and to allow for a slight variation in extrusion ratio A glass coating which was molten at the extrushysion temperature was applied to the billets and served as the primary lubricant Additional lubrication was provided by Fisk-604 grease that was applied to the tooling Five of the billets were extruded at 1200degC and one at I250degC Low extrusion rales (ram speeds) were used to prevent a sufficiently large temperature increase that the incipient meiing temperature of the alloy would be exceeded otherwise serious cracking could result This problem was encountered during the develshyopment of standard Hastelloy N but was solved by conshytrol of extrusion rate
The results of extruding the l7r Ti modified HaMclloy N billets in the order performed are pre-
67
sensed in Table ftI Fur the first three tube blanks produced extrusions lottf 104 and 1605) die low rale of extrusion caused mandrel taawre d w to ecev I I K healing vf the tooling However ike length of tube blanks obtained with various extrusion ratios and ram speeds suggested that the combination of tooling used lor extrustoR 1604 (extrusion ratio of deg41) with an extrusion speed approximaidy equal to that of extrushysion 1605 125 m sec) should produce a complete tube blank This was die case for extrusions I60K and I6QN In an attempt to reduce the force required to make these extrusions the final tube blank lexirusion 1611)
was extruded a a slightly higher temperature 12501 A rather long length ol good extrusion was obtamed but mandrel fanure agam occulted due to the low extrushysion speed
Visual inspectioK of die tube blanks showed die OO surfaces to be quite good as must rated m Hg 617 wfwch shows the lesdmg end of extrusions I60K and 160V O i dae other hand boroocopic examination ol the IDs by die outside vendor performing the redraw operation revealed flaws winch were subsequently removed by gun iriEing These flaws shown typically in Fig 618 a=e believed tc be caused by inadequate lubn-
m-n
Flaquo l seamless tuctnc
H r ( lt 4 gt M u i r K T i - i N (fecal 75-42 h Slock for ramm bwVt o produce
Tafefc-tl snd raridof n w Mask cxtrwOTMvav2t Timdashnodinnl Nattdby N (beat OTI8-5-Mll|(B
Fxtruuon Die diameter i in i
1603
1604
1605
i475
1625
1475
Mandrel dumcrrr
in)
K IruMt-n Rjm speed ratio (in laquo i i
Force ttonsi
Maximum Running itesuils
0813
JO
0812
114
94 I
1041
15
15
25
1230 l l l l Good 0D surface 22 m of tube blank extrusion before mandrel fadure
l6igt 1100 Good OD surface 45 in of tube Hank extrusion before mandrel fadure
12f0 12i Good Oigt suriacc 4raquo in of rube blank extrusiim before mandrel failure
1607 1625 10 941 Stalled operational error
1608 1625 10 941 36 12911 1290 Good Ol) surface 70 in lube Mank extrusion
1609 1625 10 941 36 1290 i290 Good OIgt surface 70 in tube blank extrusion
1611 1625 10 941 10 1000 900 Repeal of extrusion 1607 jtood OD surface 55 in of lube Hank extrusion before mandrel failure
Notes Container diam 4060 in hxtrunon temp 1200deg (except extrusion 1611 at I250C Lubrication class on billets f-isk-604 jcrease on tooling
68
nraquolaquo15M-79
M06
760 Fig 617 Tibr hlanfc exuasjom of 2 Ti-wdifM I fuWuj N (heal 75-421 These are ihc leading ends or the two extrusion
and were photographed in the as-extruded condition
O O-
O O-
O ho d
Fig 618 Typical defects M I the made diameter of extruded lobe Wanks o 7 Tr-modifod rlartcBoy N (heat 75-421) Longtludinal section Ffched wrlh glyceria rejtia tOOx
69
cation during extrusion Therefore several additional extrusions are planned to test ihis assumption and to evaluate other lubricants The bilets will be prepared from the 6-in-diam bar fabricated from the same comshymercial heat used for the previous bitten
The products of the six extrusions (Table 61) were sent to an outside vendor for redrawing to finished tubing More effort was required than anticipated due to several factors the conditioning required to dean up the surfaces of the extrusions experimentation with both plug and rod drawing techniques to establish a workable processing schedule and more frequent and longer intermediate annealing treatments than anticishypated for the alloy The vendor believes that a satisfacshytory drawing schedule has been developed and is proshyceeding with processing of the remaining extrusions The vendors preferred process involves rod drawing and sinking operations requiring about 18 to 2ttS deformashytion per pass with intermediate annealing treatments at I I77C followed by water quenching Quality control steps after each process step irJ-de light etching folshylowed by visual inspection of the OD and boroscopk inspection of the ID for defects It is believed that the yield of tubing from the redrawn ORNL extrusions will be sufficient for at least one of the two forced-circulation loops now under construction
A 6-tt length of cold-worked 075 m-OD X 0072-in-wall tubing was received as product from the development work required to establish a drawing schedule The tubing is being evaluated by nondestrucshytive techniques Liquid-peneirant inspection of the OD showed no defects Silicone rubber replication together with radiographic inspection indicated the presence of relatively shallow crackiike indications on the I D over a 4-ft length Meiallographic examination of a small sample from the did of the 6-ft section showed the defects to be J maximum of 0028 in deep The tube will be annealed and inspection will be repealed including examination by an eddy-current technique In view of the number of process variations to which the tube was subjected in developing a drawing schedule the quality of the OD and that of portions of the ID is encouraging
622 Seimprodlaquoctiontfeatsof2ri-Modified Hastdoy N CoiriaMng Niobium
To provide stock for a more complete characterizashytion of niobiunviiianium-modified Hastelloy N eight SO-lb heals and one 2S0C lb heat (Table 62) are being prepared by a commercial endor Niobium additions lo the 27 Ti modified Hasieloy N base arc of interest for enhancing resistance to tellurium embritilemcnt and
Bve Ni-12T Mo-7laquoS Cr-21 Ti-007 C
l ov Addition of the jadiciied rirMear 4) Heat
laquoze lltraquo
Jmr re Si Ma Nb
Heat laquoze lltraquo
i 10 01 02 085 -115 2500 10 01 02 04 06 50 IO 01 02 135 -165 50 10 01 02 18-22 50
30 50 01 02 085 11$ 50 10 01 - 02 02 085-115 50 10 01 02 05 085 115 50
8 30 50 01 02 02 -05 085-115 50 bull 10 01 02 085 115 50
Indrndnl nines denote maxnnom coaceMnrioa
niobium levels between 05 and 2 wt It w i l be investishygated Ir addition the compositions of four of the alloys were chosen to investigate different levels of the residual elements Fe Mn and Si These results will be important because of the beneficial effects of the residshyual elements upon oxidation resistance and will allow greater latitude in scrap recycle
The nine alloys have been melted and will be procshyessed lo products in the near future The eight 504b melts will be forged and rolled to ^-in-thkk plate approximately 4 in wide This material will be used for voidability salt corrosion tellurium compatibility and mechanic property tests The 2500-lb heat will be conshyverted to t |raquo- V - and | k-in-diam bar products and to a 4 X 4 in round-cornered square bar About half the material will he retained in the last form lo allow future capability for producing additional products of sheet bar and tubing
6 J WELDAMLITY OF COMMERCIAL ALLOYS OF MODIFIED HASTELLOY N
B McNabb H E McCoy T K Roche
Welding at ORNL is generally performed in accordshyance with Section IX of the ASME Boiler and Pressure Vessel Code2 Basically this requires that a procedure for welding a material (or class of similar materials) be developed and that welders demonstrate that they are qualified to weld by the procedure The procedure must
2 ASMt BoHer and Pressure Vessel Code Section IX Qutt ifuvxm Standard for Welding and Braimg Procedures Weldm Bnm end Welding and Brtittg Operators American Society of Mechanical Engineers New Ywk 1974
70
be a written document including die essential variables associated with making the weld and must be backed by test reports including bend and tensile tests which show that the weld is sound A welder can then be qualified to use die procedure by making a weld which is subshyjected to bend tests to show that it is sound This is a very suupKfied view of the process used to develop and maintain high welding standards and the ASME Boiler and Pressure Vessel Code Section IX 2 should be conshysulted for more detal The Plant and Equipment Divishysion main tains a weld test shop under the supervision of D R Frizzed to implement the process and this shop is frequently assisted by the Inspection Engineering Department
Procedures were previously developed for joining HasteHoy N to Hastdloy N (WPS-1402) and Hastettoy N to die austemtk stainless steels (WPS-2604) but it was necessary to demonstrate whether these procedures apply equally weO to 2 Ti-modified HasteBoy N Therefore K-n-thkk test plates of 2 Ti-modified Hastelloy N (vendors heat 2810-4-7901 designated ORNL heat 74-901) were prepared and welded as folshylows autogenous welds with 74-901 welJ wire welds with 2 Ti-modified Hastelloy N weld wire (vendors heat 8918-5-7421 designated ORNL heat 75-421 welds to standard Hastelloy N heat Nl5075 with 2 Ti-modified Hastdloy N heat 75-421 weld wire and welds of type 304 stainless steel heat 18024 with Inco 82T heat NX59I38-D wdd wire Each raquo d d was subshyjected to visual dye penetrant x-ray and metallo-graphic ixr^mation and to two tensile and four side-bend tests These tests were conducted in accordance with die ASME Boiler and Pressure Vessel Code Secshytion IX 2 and ail of the above-mentioned welds passed the tests The tensile specimens were machined from the test plates with the weld in the reduced-section gage length and were tested in a Baldwin tensile machine All Hastelloy N welds exceeded the required minimum 100000 psi ultimate tensile strength except the weld of 1 Ti-modified Hastdloy N to type 304 stainless steel which ruptured in the type 304 stainless steel base metal at 93300 psi The side-bend specimens were A X li X approx 8 in long with the weld in the center and were bent around a I-in radius in a guided bend fixture
The chemical analyses of the various materials involved are shown in Table 63 The side-bend specishymens are li in (luck X hi in wide bent around a l-in-radius mandrel in a guided bend test The specimens were macroetched in a solution of HO 20 HNOj -20 H 2 0 to delineate the weld and heat-affected zones Figure 619 u a macrophotograph of side-tnd specimens of standard Hastelloy N heat
N1-5075 Vi-in-thick plate welded with standard Hastelloy N wdd wire heat N I -S I0 I There were no fiows in the specimens after bending and visual dye penMrant x-ray and mrtallographic examination before bending showed that the welds were sound This weld was inde and tested to recertify the welder and to update the welding procedure specification Figure 620 is a reacTophotograph of side-bend specimens of 2 Ti-modified Hastelloy N (top) (heat 74-901) welded to standard Hastelloy N (bottom) (heat N1-5075) with 2 Ti-modified Hastelloy N (heat 75-421) weld wire by welding procedure specification WPS 1402 There were no flaws in the welds and the strain markings delineate the weld areas
Figure 621 is a macrophotograph of 2 Ti-modified Hastelloy N plates (heat 74-901) welded with 2 T i -modilied Hasteiloy N (heat 74-901) weld wire on weldshying procedure specification WPS 1402 There were no flaws in the welds and the specimens were macroetched to delineate the weld areas Figure 622 is a macro-photograph of the same heat of 2 Ti-modified HasteBoy N (74-901) welded with 2 Ti-modified Hastelloy N (heat 75-421) weld wire by specification WPS 1402 There were no flaws in the welds and the specimens Figure 623 is a macrophotograph of side-bend specimens of type 304 stainless steel K-in plate (heat 18024) (top) welded to 2 Ti-modified Hastdshyloy N (heat 74-901) (bottom) with Inco 82T (heat NX 59138-D) weld wire by welding procedure specification WPS 2604 There were no flavs in the welds and the specimens were macroetched to delineate the weld areas
Although special welding procedures were prepared for the joining of standard to 2 Ti-modified Hastelloy N with 2 Ti-modified Hastelloy N filler wire (WPS 1403) and for joining stainless steel to 2 T i - modified Hastdloy N with Inco 82T filler wire (WPS-2606) the parameters used in making these welds were identical to those used in procedures WPS 1402 and WPS-2604 developed for standard Hasteiloy N Thus we believe that the test wdds adequately demonstrate that stanshydard and 2 Ti modified Hastelloy N have equivalent welding characteristics and that procedures WPS 1402 and WPS 2604 can be used for both materials
Supplies of standard Hastelloy N weld wire were depleted over a period r f time and additional wire was purchased to the materials specifications MET-RM-304B However the voidability test was performed by O R N L Plates of standard Hastdloy N (heat 5067) IV t
X 4 X 10 in were welded with the new heat of weld wire from Teledyne Allvac (heat 9725) using welding procedure specification WPS 1402 and were accepted
71
Jiilln l i s i l
1 3
3 laquo m i a m I z
llllpl liillii s a = c e e v
i
i
I I I
Hill s s = s e
Ii2s I
I bull raquo bull
S C O
33 a c e o 3 O m
i
bull mdash copy o r- d 9gt
laquobullraquo bull gt ampgt ltlaquo rraquo laquo r i mdash
1 laquo
z z z
r t a laquo m r- f 2 gtgtilti bull laquor mdash H-
2 2
i ij
72
Ffcfc1 Bead N(heMNI-S075)j Htmuwwtt SIM)
Ffe gtJ0 I M 4 ffcciMtM of 2 T t - m o t f M HmHtoy N (fctrt 7901) art staataaJ H n M o r N (fcMNI-5075) j o M w M i Tt-modiTM Hartdoy N Mkr win (beat 75-421)
73
F laquo J I (heat 74401)
Ffe 622 ttmt (raquotat 75-421)
of J Ti-motfbJ HMcltoy N (beat 74401) f o M wMk 2 Ti-amtttM
74
FlaquoftJ3 i01 tyyc39v 3 I H T H N ( laquo laquo 7441) j IwMUTflkr
as passing all tests including one all-wdd-inetal tensile test and four side-bend tests with no flaws in the welds This material has been made available for general proshyject use
4 STAWLrTY OF VARIOUS MODIFIED HASTEIXOY N ALLOYS IN THE
UNIRRADIATED CONDITION
T K Roche H E McCoy J C Feltner
The stability of Nb- Ti- and Al-containing modified Hastelloy N with respect to intermetallic predpitation known as aging is being studied It is known that addishytions of these elements are desirable respeclivdy for enhancing resistance to tellurium-induced intergranular cracking for improving resistance to radiation embri-tlement and for deoxidizing the alloy during melting However beyond certain levds these dements can cause aging reactions by the predpitation of gamma prime |Nij(AITi)| or NijNb which in turn causes hardening or strengthening and loss of ductility Therefore studies are in progress for defining the amounts of Nb Ti and Al which can be added to Hastdloy N and still maintain a reasonable decree of stability The stabilities of a number of alloys including laboratory semiproduction and production heat having varying amounts of the
demenu in question are being determined by hardness tensile properties creep-rupture properties and micro-structural evaluation
The first approach to evaluating stability has been the determination of the room-temperature hardness of the various alloys before and after heat treatment at 650 704 and 800degC for periods up to 1000 hr The data for alloys held at these temperatures for 100 hr were reshyported previously1 and during the present period the 1000-hr data presented in Table 64 were obtained he data for alloys which show significant hardening relative to the as-annealed condition are Mocked off in the table
The hardness of the various alloys after a 1000-hr aging period follows the same pattern noted for the 100-hr aging period However the previously reported niobium concentrations of the niobium-containing alloys were low due to an analytical error the correct values are shown in Table 64 The present data show that with low aluminum concentrations (00S wt ) niobium contents approaching 2 (rather than as conduded earlier) can be tolerated in 2 Ti-modified
3 T K Roche D N Braski and J C Felfnrr MSK Pro-gum Semmnnu fmgr Rtp Feb 2S 197$ ORNL-5047 pp 71 76
75
lkra llaquoMi7WMri l
DatamMoriui hatdcMBg rcbthc to the
Icoaditiw
IoapoBtun (laquot ) Rockwell
Heat IoapoBtun (laquot )
AaaeaM (
Agt4 1000 were 704c
hr Nb Ti Al C AaaeaM
(
Agt4 1000 were 704c sooc
474-557 214 002 004 SI 5 S7S SSS S74 472-503 194 009 006 S44 S9S 882 891 474-901 IS 010 006 794 857 S63 856 471-114 1- 012 005 792 829 846 S44 427 24 0IS 0014 747 784 773 779 428 247 016 0064 S25 SS2 861 860 474-533 217 04S 005 Sl0 857 S62 849 474-534 209 053 008 893 925 904 909 429 24 0J5 0017 769 9 4 854 74 430 25
2J 034 074
0073 0016
SS6 7S6
1001 88 9 912 431
25 2J
034 074
0073 0016
SS6 7S6 978 984 928
432 048
235 19
069
008
0057 0037
874
SOI
1034 1034 974 425 048
235 19
069
008
0057 0037
874
SOI 841 858 852 421 10 19 007 0048 873 865 878 867 424 134 I S 010 0063 S84 902 SS9 904 418 192
190 20 18
005 015
0058 0055
891 S87
904 900 9IA
904 420
192 190
20 18
005 015
0058 0055
891 S87 1015_
900 9IA 913
435 142 23 015 004 886 1050 1021 903 43S 180 24 013 005 918 1066 1051 968 433 189 2 2 033 0024 848 1043 1021 881 434 186
252 2 bullgt
22 032 015
0061 005
933 931
1070 1088
103 8 1076
957 441
186 252
2 bullgt
22 032 015
0061 005
933 931
1070 1088
103 8 1076 1041
442 30 22 014 0052 950 1093 1096 1072 30 22 014 0052 950
Bavt Ni l2TMo K Cr l h r j | IMTC
Hastdloy N before aging occurs However the tolerance for niobium decreases with small increases in the titashynium and aluminum contents It must be emphasized thai the hardness data were obtained on unstressed specimens and that creep-rupture tests now under way indicate that lower concentrations of niobium are tolershyable when the alloys are subjected to stress These reshysults arc described Uter in this section
The effect of aging on room-temperature and elevzed-tempcralure tensile properties is being detershymined for most of the alloys Limited room-(emperalure results have been obtained after a 100-hr aging period at 650 and 800degC (Table 65) There is good correlation between the tensile data and the preshyviously reported hardness data As would be expected alloys which age harden during a given thermal treatshyment (data underlined in Table 65) also show an inshycrease in strength and a corresponding decreur in ducshytility relative to ihr solution-annealed condition
In the case of the tiunium-aluminum-modified Hastdloy N alloys the hardening phase is most likely gamma prime and this phase has been identified in heat 430 lt 25^ Ti + 034 Al) after 100 hr at 6 5 0 o C
Stress-rupture results for the titaniunvaluminum-modified Hasielloy N alloys at 650 and 704degC are shown in Tables 66 and 67 respectively Again there is very good correlation between age-hardening behavior as determined from short-term hardnlaquo data and the corresponding rupture life in the stress-rupture tests Abo the effect of temperature upon agmg an be seen by comparing the data sets for heats 429 and 430 at 650 and 704degC At the lower temperature both of these alloys hardened but neither hardened at 704degC Since hardening in these alloys is due primarily to the formashytion of gamma prime these results sugges that the gamma prime solvus temperature is located between 650 and 704degC for these two alloys This observation and the other aging data in Tables 6465 and 66 were
76
Tak6-5 raquo i m l all l i l i h t i i i i i i fci iwfNJ-TVAI
iicbtaKtodK
bdquo laquo t t m t ~ - - - StteaajbUO neat _ ^ _ ^ ^ _ _ _ _ _ _ ^ ^ ^ _ _ l o a a m _ ^ _ ^ _ _ _ _ _ Doaaaboa ()
iraquo r At c mum Y j - i ^ ^ 474401 18 010 00 AnwaM Ikr l 7 r c I MO 442 447 794
Aaoil00br50C 114 J $00 559 SIS Aged 100 brS00C I I9JO SI2 537 151
428 247 0 1 00 A a w a M l k t I I 7 T C 124 J 49-0 52 825 Aged 100 br50C 125J $0-5 527 M2 Aftd l0fgtbrS00C 1237 511 411 M7
430 2J 034 007 Aaneakdlbf I177C I2SJ $00 541 St Aac4IWbr5ltrc 1348 634 437 957 Aged 100 brS00C 12 J 531 $00 886
424 134 I a iO 00 AMtafcdlbr I177C 1372 527 512 Ago i00br6$OC 1385 52J 477 (93 Aged 100 brSO0C 1377 547 45S 199
435 142 23 015 004 Aaaeakd 1 hr 1I77C 12S4 510 54 raquo Aged 100 br50C 190 893 353 1025 Aged l00brSOOC 1339 54-5 S3S laquo73
442 30 22 014 003 Aantakd 1 hr II77C 1394 07 $42 Agadl00bf50C 1905 107 251 AftdlOObrSOCTC 144 ~ J 3 J 1 S 9
bull raquo Ni-12 Mo-7 O
TaMe64 St iwiaptmdashe data for wr iow beats of Nb-Tt-AI R M d M H a s t d b ^ N at 6500 aad 474) x I0gt pa
Heat Composition (wt gt Rupture
life (hrgt
Total strain
Are harden Heat
Nb Ti Al C
Rupture life (hrgt
Total strain at 650deg C
474-901 18 010 006 3950 270 No J74-533 217 048 005 4650 280 No 427 24 118 0014 866 217 No 428 247 016 0064 1150deg 73 No 429 24 03laquo 0017 9572 163 Yes 430 25 034 ftO^ 16980 73 Yes 431 2$ 074 0016 23090 101 Yes 432 235 069 0057 41710 21 Yes
42S 048 19 008 0037 14301 237 No 421 104 19 007 0048 20070J 73 No 424 134 18 010 0063 39530 65 No 418 192 20 005 0058 39550 32 No 420 190 18 015 0055 39510 19 Yes 433 189 22 033 0024 41690 10 Yes 434 186 22 032 0061 39550 09 Yes
BaseNi 12 Mo 7Cr Based on turdnest measurements on aged umircutd specimens Tesl still in progress Test discontinued prior to fracture
used to estimate the gamma prime solvus temperature boundaries at 650 and 704degC as a function of aluminum and titanium concentrations Alloys with compositions lying below the proposed boundaries in Fig 624 are stable at the indicated temperature and those above will precipitate gamma prime
With the addition of niobium to titanium-aluminum-modified Hastdloy N defining or predicting stable comshypositions becomes more complex There is evidence1
that mechanical stress significantly affects age hardening of these alloys which is not uncommon The room-temperature hardness data for annealed and aged specishymens of the various Nb-Ti-AI modified Hastdloy N alloys suggest a tolerance of about 2 Nb in a 27 Ti-0-5 Al modified Hastelioy N base (heat 418) beshyfore aging occurs Further increases in the aluminum niobium and titanium contents lead to age hardening at 650degC then at 70degC and finally as high as 8O0degC when the niobium content is increased to about 25 with 22 Ti and 015 Al (heat 441) If the broad assumption is made that the three elements are equally effective in promoting an age-hardening reaction and a plot is made of the total atomic percent of these deshyments (at Nb t Ti + Al) in the various alloys against the increase in hardness (^RBI caused from aging 1000 hr at 650degC a curve is obtained (Fig 625) A sharp break indicative of appreciable aging occurs between 3H and ^M at 1 (Nb + Ti + Al) Adding the variable of stress to aging response and plotting the parameter of minimum creep rate from creep tests at 650degC and 470 X I0 3 psi (Table 68) against total atomic percent (Nb bull Ti + Al) results in the curve shown in Fig 626 The break now is indicated between 2 and J at (Nb + Ti bull Al) The creep rale of alloys containing up to about 2 at rlt (Nb bull Ti + Al) is 15 to 30 X lO^ h t Three heats (70-835 6laquo-648 and 64gt-344) in the 2 to 3 at ^
region which are high in niobiuro and low in titanium are known to age upon creep testing at 650degC at d exhibit creep rates around 1 X 10Jhr One heat (425) with the reverse combination low in niobium and
4 H y McCoy MSK Program Senu4m1L ftogr Rep Feb 29 1972 ORNL-4782 pp 167-69
30
25
7s- i sm
20
z
z o u
15
10
05
NO y
bull704-C -
650 C
02 04 06 Al CUfTENT ()
08 10
F|laquo 624 PlUMJWa bullOMIMJM MSWatl Sttbfc fan bullraquo-staMr alaquoovs of N i - I raquo M o - 7 Cr bull Al and Ti with remcct to p i M prime precipicslioa m S0 and 704degC Alloys above the lines win form ttamma prime and those below wifl not (see Table 64 for the compositions o f the various alloys I
Tab 67 Stress-njptare data for several Urals of litaMM-almiNMM modified Hastetoy N at 704 C and 3SJO X 10 psi
Ileal Compoutiofi twt bull 1
Ti Al
Rupture life (hr)
Total strain
Age hardens at 704C
474-901 474-5 J J 427 428 429 430 431 432
18 217 24 247 24 25 25 235
raquollraquo 1148 IMS 016 035 034 074 069
006 005 0014 0064 0017 0073 0016 0057
1932 I96 0 820
2018 2006 2124
29383 36115
394 420 234 610 227 558
68 137
No No No No No No Yes Ves
Base Ni I Z Mo in Cr
Result ltgtf hardness measurement taken on ated unsirnsrd specimens
78
7S-1JTraquo 20
raquobull
14
an c
i lt
laquo0
bull433
bull 435 U^TA j raquo44l
438 _Llaquolaquo
420
- bull 4 2 5 -
bull 434
mdash~3poundt^~ 4lt8
25 30 42t -bullmdash 35 40 45
at (NbraquoTraquoi) 5 0
Fij 6 J5 Chante M kmimm ol 1 vanon beats of Nb-Ti-AI-amdiTied Haste N after 1000 kr at 650C (see TaMe 64 lor the coMposinons of the bullMiow alori)
TaMe 64 Coayison of hardness changes4 aad creep beharioi of Hasteloy N moOfttd with Nb Ti sad AI
high in titanium does not seem to show much aging Alloys containing 3 to 5 at (Nb bull Ti bull Airaquoage appreshyciably with creep rates of about I X IO3hr or less
The above results indicate that zlloys containing approximately 25 at or less (Nb bull Ti + All will be satisfactory from the aging standpoint Such an alloy would be represented by the composition on a weight percent basis of 05 Nb-I5 Ti-01 AI Alloys having concentrations of Nb + Ti + AI above the 25 at range will be more susceptible to aging
Future work will include evaluation of mkrostructure for a number of these specimens to confirm present conclusions evaluation of additional alloys to test the indicated boundaries for stable compositions and an extension of data analysis to determine whether a quanshytitative relationship can be derived that separates the relative effects of the individual elements Nh Ti and AI on the stability of alloys of this type
65 MECHANICAL OPERTIES OF TOANIUM-MODIFIED HASTELLOY N ALLOYS
IN THE UNIRRADIATED CONDITION
T K Roche J C Feltner B McNabb
Several tests were completed or are in progress to determine the mechanical properties of recently reshyceived heats of 2 Ti modified Hastdloy N in the unirshyradiated condition These alloys include two production heats (74-901 and 75-421) and six semiproduction heats (74-533 74-534 74-535 74-539 74-557 and 74-558)
behavior of several heat
Composition Hardness Kg Minimum creep rate
Cilhx) Heat wl 1 at Annealed 1000 hi
al 650C Change Minimum creep rate
Cilhx) Nb Ti AI C Nb fi + AI
Annealed 1000 hi al 650C Change
237 103 004 lt005 084 15 x 10bull 63 25 lt00I 013 166 il X 10 181 185 050 lt001 0045 186 31 x 10 bull 69448 195 092 005 0043 255 70 x 10 69-344 17 077 024 010 263 26 X 10deg 70-835 26 071 010 0053 282 60 X 10 425 048 19 008 0037 290 801 841 40 78 x 10 421 104 19 007 0O48 324 873 865 -0 8 13 X 10 424 134 18 01 0063 338 886 902 16 71 x 10 418 192 20 005 0058 391 891 904 13 22 x 10 420 190 18 015 0055 387 887 1015 128 1 X 10- 433 189 22 033 0024 475 84 1043 195 2 x 10 434 186 22 032 0061 470 933 1070 137 3 x I 0 -
Alloys aged for 1000 ht at 650degC and hardness measured in unstressed condition Creep tested at 650deg C and 470 x 10 psi f Base Ni 12 Mo 7Cr rflhratll77C
79
6 OANL-OTN 75-Wtf
5 5 k 433 1 raquo434 | 1 1 iHll
- (
I
gt420 M 1
1 tlltk^
- (
I i i
70 -835 lt i T ^ 1 | U 1 bull 69-648 6 - 4 4
I
1 425
2
1
I II 1 i i |
bull S3
M81 2
1
1 1 1 1 i
1 |
bull 237
I 1
10 i - raquo tor4 2 5 laquo r 3 2 s MINIMUM CREEP RATE 1nr)
10 io-
F 626 MiMam cteep rale of vwkms heals of Nb-Ti-AI-nodified Hastelloy N tested at 650degC aatf 47Jgt x 10 pa (s Table 64 for the aloy coiapositicm)
Four of the six semiproduction heats contain small additions of rare earths lanthanum cerium and miscii metal The compositions of these alloys were chosen to study the effectiveness of rare-earth additions for minishymizing the extent of shallow intergranular cracking Each of the six semiproduction alloys was the prodxct of a 120-lb double-melted (vacuum induction plus elec-troslag remeit) heat produced by an outside vendor The chemical analysis of the alloys was reported preshyviously5 The mechanical-property studies include the determination of room- and elevated-temperature tensile properties and creep-rupture properties in air at 650 704 an J 760degC These data serve as a reference for comparison with the properties of standard and other modified Hastelloy N alloys both in the unirradiated and irradiated conditions
The principal effort during this report period was directed toward completing the creep-rupture data on the above heats Tests are being run at three stress levels for each of the three test temperatures Most of the tests were completed with the major exception being heat 75-42 he 8000-lb production heat for which specimens are being prepared Specimens of the other
5 T K Roche 8 McNabb and I C Kcliner MW flj-gnm Stnimnu Progr Rrp Feb 2 1975 ORNL-5047 pp 61 and 65
heats were obtained from swaged rod and were annealed for I hi at 1177degC prior to test
Figures 627 through 629 are plots of rupture time as a function of stress at 650 704 and 760degC respecshytively for the 2 Ti modified Hastelloy N heats and are compared with plots for a previous heat ^471-114) of the same alloy and standard Hastelloy N Minimum creep rates measured from these tests a the three temshyperatures are shown in Fig 630 as a unction of stress As concluded previously the more recent heats of 29t Ti modified Hastelloy N are essentially equivalent in strength to the earlier heat and there is no significant effect resulting from the addition of rare earths to the 2 Ti -modified alloy As determined from past work and confirmed by the recent tests the modified alloy exhibits longer rupture lives than standard Hastelloy N at the three temperatures
Additionally the first of eight creep machines capable of tests in molten fluoride fuel salt was put into operashytion A specimen of heat 474-533 has been in test at 650UC and 300 X 10 3 psi for slightly over 1300 hr Data are not available as yet on this same heat in air but a comparison is made in Table 69 with an air test of an earlier heat (471-114) of the same nominal comshyposition
The data appear to be falling within a normal scatter band for alloys with the same nominal composition that
80
10 2 5 KT RUPTURE TIME (Dr)
Flaquo 6-27 Sueswuptare properties of several heats of 2 Ti-modified Hastcfloy N and standard HasteRoy N at 650 C I Ranges of rupture strain indicated in parentheses)
60
90
= 40
laquogt 30
20
10
0MH-DWC 79-laquoS7raquo0
[ mdashr-1 i j
- laquo gtlaquo 2 Ti-MODIFI bull0 bull AS El -LOT N (HEAT 4 r i - iu raquo i h t
B ( 39
h 4 -
r
II 6261 r ( 3 7
bullIs
I 2-476) -
laquobullraquo bull (
i
bull 174- 33
1
39
h 4 -
r
II 6261 r ( 3 7
bullIs
I 2-476) -
laquobullraquo bull (
368-47
1 6
A 474-535 laquo 474-539 o 474-557
-STANOARS HA STE
I-
LL OY N
o lt raquo74-laquo
1 L
KM
1 1 TES II
T TEMPER
III ITUR
STE
I- 70 4C
11 V 2 10 tOJ 10 RUPTURE TlaquoE (hr)
Fit 62 Strcavmpfare prupeniei of several heats of 2 Ti-modrTwd HacMfojr N aad staadaid HaateBoy N at 704r (Ranees of rupture strains indicated in parentheses)
81
Tvaoraquo 35
30
25
I- -
11 1 1 1 M IMP i | TT bull1 X I i h i j i i
bull -MODIFIED HASTEU0Y N CHEAT 471-14 -1 i IIIH |
i bull i i i
i gt lt
I i h i j i i bull -MODIFIED HASTEU0Y N CHEAT 471-14 -
1 i IIIH | j
j
j | i i
M 1 nH t t Y-
r 1 i n 1
t bull 1 I t I i |
i i i i i V bull i i bull i bull
raquo 474-533 gt 474-534 i 1 M h i t raquo 474-533 gt 474-534 I r bullv M I f f bull 474-535 raquo 474-539 I M i i i 11
o 474-901
1 Mi l l i i T
1
TEST TEMPERATURE
ill I i BOT
i IN to bull 0 2 2 5 SO5
RUPTURE TIME ffcr) bull0
F i j 6 2 9 Strcss-raptate properties of scleral heats of 2 Ti-modified Hasttstoy N and standard lUiMMoj N si 760C- (Ranee of rupture strains indicated in parentheses)
omn-oac n-tsret TV
f 2 5 raquo - MINIMUM CREEP RATE (hr)
Fig 630 Creep properties of scmsl heats of 2 ft-modified HasteHoy N at 650 704 and 760 C Solid lines arc for heat 71-114 and the dashed lines indicate bands which contain the data for the other modified alloys
S2
T M H -Ac mdash l i i r a s w a raquo laquo 1 l
larl 474-533 471-114 iflaufijc farii ltagt
500 13 24 1000 44 1300 35 55
Tlaquowraquo ion ai 650 C n d 300 x 10 pa
are tested under similar conditions and there is no indication that ronoaon by the molten fluoride fuel salt represents a sgmficani factor
jraquo rOSTIRRADUTIONCREEf MtOftRTIES OF MODIFIED HASTELLOY N
HE McCoy TJC Roche
puurade of the ORR Each experiment contains 102 miniature creep specimens in an instrumented facility in whkh temperatures can be measured and controlled by supplying heat from auxiiary heaters Only 12 in-ceU creep uwrtnim are available for postirradianoa creep testing hence the testing proceeds rather slowly The most recent tests have concentrated on lt I ) the propshyerties of six 125-lb senuproduction nests that contain 2 Ti and low concentrations of rare earths and (2gt the properties of several alloys containing both niobium and titanium
The results of tests completed to date on the six heats that contain titanium and rare-earth additions and the (OjOfXKb commercial heat that contains titanium are summarized in Table 610 Previous tests at temperashytures of 6S0 and 704degf showed that the creep propshyerties of these heats are about equivalent The rupture nfe at 650degC and 40JO X I 0 3 psi varied from 1200 to iSCC hr and the rupture life at 704degC and 350 X 10 psi varied from 170 to 200 hr Final conclusions con-
Postirodtion creep tests are in progress on specishymens from five experiments that were irradiated in the
6 T K gnmSemm
Roche i ( l-dlner and B McXabb MSK Pro-mm flop Rep Feb 2 1175 ORNL-5047 p 7
a t 6 S r C a r laquo s a o M n i atUttMecatca
ABojr Ten mantel
Irradiation tcmpcniafle Si ecu
(10 pa) creep rate
(hr)
Rapawe life (hrgt
Total fracture straia Cufaycailioa (gt
474533 R-I9I2 R-190
R-I929
650 650 7ltK 760
400 470 400 350
0025 0050
0035
2311 I I I 5 2
2022
72 217 Ti 04 At 7 6 4 7 J
474-534 R-1913 R-1909
R-1930
650 650 704 760
400 470 400 350
0021 007
0008
5722 660 5raquo 7 3
16 2 209 Ti 0 J 3 Al 001 3 La 69 35 28
474-535 R-I9IS R-I9I I R-1922 R-1926
650 650 704 771
400 470 400 350
0016 0099 0023 0019
7 6 M 930
4677 6454
1V6 2 1 3 Ti 055 Al 004 rare car TS
123 139
474-539 R-I9I4 R-I9I0 R-I92I R-1925
650 laquoS0 713 774
40 JO 470 400 350
0020 011 0C3I 0000
601 739
4295 12200
108 193 Ti 020 Al 003 Ce 97
165 114
474-557 R-1920 R-1923 R-1927
671 713 771
470 400 350
0045 0044 0019
2174 162 434S
1 0 214 Ti 002 Al 95 S3
474-55 R-I9I6 R-1924 R-192
650 716 795
470 400 350
0X192 0021 0012
1793 475
79 205 Ti 0-02 Al 002 U 6 II
474-901 R-1936 R-1937 R-1907
650 70laquo 732
470 470 470
0069 015 014
1716 332 525
1 3 10Ti00Al 52 1A
AD specimens lancaM I hr agt 1177C prior (o irradiation for M 100 hr to a thermal thence of vlt3 x 1 0 neutronscm Alloy nominal bast composition of Ni 12 Mo 7 Cr -005 C
S3
cerning the postinadiation properties (Tabk 610) are not possible because the tot matrix ha not been comshypleted Specimens irradiated at 650degC and tested at 650degC hare rupture lives that are about half those of the unirradiated specimens but there are no differences in the properties of the various heats that are considered significant in view of the limited data The properties of afl heats are considered good after irradiation at 650C After irradiation at 704degC and testing at 650degC and 400 X 10 pa the rupture lives of heats 474-533 and 474-534 appear to be lower than those for the other heats by a factor of 3 In afl cases the rupture life and the fracture strain were lower after irradiation at 704degC than at 650degC After irradiation at V760C and testing at 350 X I 0 3 psi at 650C the rupture fafe varied from 43 to 1220 hr and the fracture strain from II to 114
respectively Thus differences in creep behavior of th-se aftoys likely become progressively more important as the irradiation temperature is increased
The fracture strains of the various heats appear to show significant trends with increasing irradiation temshyperature Heats 474-533 and 474-557 have good fracshyture strains (6 to 104) which do not decrease apprecishyably with increasing irradiation temperature The fracshyture strains of heats 474-535 and 474-539 are i t the range of 10 to 16 and do not change appreciably with irradiation temperature Alloys 474-534 and 474-558 show decreasing fracture strains with increasing irradiashytion temperature The behavior of alloy 474401 appears to be unique in that it shows a marked drop in fracture strain as the irradiation temperature is inshycreased from 650 to 704C However this effect may
Ta t 611 bullMtffiall rNamwsaKsrc
Alloy Test HftlhCT
Sims HO psi)
creep rale
Rapt me ate lthrgt
Total fraclarc sin in
rfhraquogt
Rapt me ate lthrgt ltgt
428 R-1948 470 0043 2221 119 474-533 R-1908 470 0050 I I I S 78
R- I9I2 400 0025 2311 72 430 R-1947 470 lt00049 9720 4 8 r
432 R-1946 470 lt00005l 9720 0SC
431 It-1945 470 bullCO0024 972f 424 R- I9 I9 350 Mraquo 3160
400 000024 1406 470 000033 4526 550 00066 9494 78
424 R-1944 630 00096 3554 104 420 R-I9I8 350 bullM) 5322
400 -v-0 1405 470 000021 4509 550 000037 6959 630 000080 3343 700 00062 2776 4 3
420 R-1943 630 lt000l7 10680 18 418 R 1917 350 000002 6514
400 000007 1406 470 000014 4523 550 00040 7948 54
41ft R-1942 630 00022 5592 72 434 630 lt0085 129 II 433 R-1949 630 lt0 00 l l 6600 075
AN specimens annealed I hr al I I77degr prior to irradiation Irradiation carried out al 650C for approximately 1100 hr to a thermal flaencc of Vraquo x 1 0 neutronscm See Table 64 for detailed chemical analyses Test still in progress Stress increased on the same specimen in the increments shown
S4
tt12 laquo T SIMMS CM
AcebaMk maibS0CbjMlaquotoi rtniliij1i4
CoMBoanmi iwt rt Co H o
lOOObraMeal
ctccp cveep behavior
bull S O T f o r V I I W b f 4
CoMBoanmi iwt rt Co mdashjn bullnn a m t H o
lOOObraMeal
ctccp cveep behavior
bull S O T f o r V I I W b f 4
Nb T i Al Nb bull Ti bull Al
428 No No No 247 Olfc 357 474-533 No No No 217 laquo4t 3 raquo 2 430 Yes Yes Yes 2J 0 J 4 492 432 Yes Yes Yes 235 0Alaquoraquo 4 A 3 431 Yes Yes Yes 25 074 4 9 424 No Yes Yes I J 4 I S 010 33 420 Yes Yes Yes 10 I S 015 3S7 4 I t No Yes Yes l laquo 20 005 3 1 434 Yes Yes Yes iaraquo 22 032 470 433 Yes Yes Yes l laquo 22 033 475
Sec Tabfc 1 4 for c l e t M e U t f e M U analyses
F I O M Table 4 rFroaraquo Table t A based ltM ctmatemiomt of data i ON novate Me aMl total u n a rfFrow Table 611
be related to the strain rate a summary these sparse data sanest that the fracture strains of alloys cow-taming only titanium and those containing titanium plus cerium remain at adequate levels as the irradiation temperature n increased while the fracture strains of the two alloys (474-534 and 474-558) that contain lanshythanum do not Additional specimens were irradiated and tested to check tins important poatt
Section 64 of this report deals in detail with the metaOurgical stability of alloys containing Nb Ti and Al in the unirradiated condition Some of these alloys have been irradiated and limited test results are availshyable (Table 6) The alloys were annealed for I hr at 11770 prior to irradiation for about 1100 hr at 650C The anneal at 1177degC should have dissolved most of the alloying dements and the subsequent period at 650degC may have resulted in the formation of gamma prime Precipitation of this embrittling phase abo strengthens an aBoy hence the postirradution creep tests should show whether significant quantities of gamma prime were formed As dacussed in Sect 6 4 precipitation of bullhis phase may be strain induced and a detailed analysis of the creep data wSI be required to determine whether the gamma prime formed m the specimens during irradishyation or whether it fonrvf as the spedmens were stressed initially
The data from Table 611 and information from Sect 64 are summarized in Table 612 which shows that the
conclusions are reached with regard to aging of creep specimen in the unirradiated and irradiated con-drtions However hardness measurements on unstressed umrradaied specimens fail to be a good indication of agt in aRoys containing nioHum Alloys having a com-tlaquoKd titanium and aluminum content as high as 357 at had excearnt postirradution properties ABuys with higher uimbimd concentrations are quite strong Kut no conclusion can be made about their fracture stains All of the alloys containing Nb Ti and Al are quite strong and can lake considerable strain before fracturing ABoy 434 has a low fracture strain waste no conclusion can be drawn relative to ahoy 433
The alloys containing Nb Tiand Al which have been evaluated thus far are likely too highly alloyed even though some of the fracture strains jre acceptable Less highly alloyed materials are being irradiated
67 MlCKOSTRUCTURAL ANALYSIS OF T i T A N M M I O W I E D HASTELLOY N
D N Braski J M LeMnaUr G A Potter
The first part of this section presents the results of microstruclural studies of two titanium-modified Hastefloy N aloys 472-503 (designated 503) and 471 -114 (designated as 114) Previous analyses of these tame two alloys dealt with their nricrostructwss after
bulls
afmf aad after postsrraanrtion creep tests In the pressai m f j i l f the nacroairaciaret ot hutfcaftoys were analyzed M an attempt 10 explain some w u l pouarsdanoa creep teattts M sptoaaas that were pven a ltjfgtrtj higher soratiua aaaeahnf treatment Move trratmttian I V mdym showed that many at the wlaquo ipninsrai owe t f i e mhumimracnni and that tkc poor creep properties ttiaMmsonsr cases tie related lo the iahomimnKitsti D M ftnamg prompted a sindy aanei at iiiiidwiag asm hinaimiatimi llamllin N aloys The problem if betw approached by rcdactae it carbon coateat of the anoy aad by gnaw carefal attention ID the tahjicatani pmmHcn The resales ot taaml narranrnti to tnWicalt hiaanpariita alloys arc pKsvnacd m BM secoad part o( thjis section
471 M f u m i r i a i J M r laquo f JkaaysSISamllH
rVanmnaaaaa O H I I o n The retails of creep ten o specimen of ahoys 503 aad 114 which had keen PKVSUmdash)y irradiated in the ORR al 7a0C Me given in I hgt 6 J I The creep tots wete contacted at 6501 n a turn and of 350 X I 0 3 pa This partwalar scots laquoraquof spnameas was designed lo show mc effect of tobmoa anatjbni remperatarc on the postkravniion aeep rop-r-re We of the naieriah The solation anneal was a I-hi heal ireainieM and was given lo all sprcimens before ikes were irradiated 4 men in Fig 6 J I ibe 503 speci-men given the standard I br at 117 ( solation anneal demonstrated food creep iiipiwic We wbifc the 114 tprvmen given the amc ircaimenl had a comparably short lifetime However with an mcrease of only ^30degC in aim latins temperature ahoy 503 had a freatty reduced lifetime wMe ahoy 114 thawed marked improvement It wn corasdered ankkety that tkese rendu coaM he canted by changes in solution anncaing tcmpcrainre alone and other posabh cxpla-aatioas were soajbl It b important to note that despite the apparent mtfaMiiy in creep behavior the properties of the 2 Ti modified alloys arc gencraiy food The problem is that lo determine why tome specimens have poor properties A bullohtlhm to this problem was sonjht by carrTafly anatyimf the microttrnctnres of the two alloy 503 and 114 tpecrmens described above
7 D N bullgt I M UMmfccr jml f i A Puller JfSff AOBVM Semtmmm ffngr Hep Am J I 174 OHm-5011 pp 2 M
n I) S Hrai I M Inraoker j J ti A fnwr 10ft rtomm Semtmmu hop Htp Frh 197 ORNI -5047 Pf i vn
am-a t-laquotlt H 0 O ^
snvss ifwfi bull raquooooraquot
llaquo00 i bull ~ i
bullooraquo 7 1
SOI I
1 z- 2 aosf tr
w r T~iHr-wV---
eoo^mdash mdash mdash - 7 - l V mdash ^
laquoooo tlaquooo laquotoo laquoJOC tOkwtio mntauvs rtanjntTtM ltKgt
Hattys SWanf IM at wfTC ahw Irmthmm toOU wr laanm
TtasmnJtvJmi eltclnm nncrattwny Samples were preshypared for iransnaanoa ekciron nacroscopv iT lMi bgt elevtropohaaaf small transverse sections a( the tested creep specimens in perchloric acid sohrtions Frfures tgt32 and 6J3 show electron naaofrapbs repteseniattvc laquogtf 503 and 114 specimens respectively Hfare tgt32 shows an area near a frain boandargt in the 503 specishymen annealed at I I 7 7 C The nacroHnictaie was obshyserved to contain NT-type jwkaiii both in the ftsin bnandiry aad m the form of tmaH ptattieis DMoca-lions were nearly always foond to be aawoMcd raquotih ike MC plasestis The 50specimen anaeaWd at iagtraquoC had ssaabw featarn laquoFsg 6-321 In both speenneas ibe MC pbielets were coaccntrated near the grain boundshyaries This tajfrsts that the element or elements (probshyably titanhan) awimf ap the MC-type carbide in both specimens wete not anifonaty dittrrbwted ihroafhoat the ntntrix Rfare 6JJ shows ehxtron araquoao|raphs of ike 114 specimens aaaeated at II77C(Fig6J3tand I204f (Fhgt 6J3raquo These specinwas also contained tine hJCMype cjrbidei bat aalwd of formmf pbtekts they precipitated oat on stscUnf faalu The suckmf fault precipitates initiate from iaiocstioat aanriaUd with preexitlmi or primary MC carbides and frow atom ( l l l l pbmrs The primary bX carbides (the dark
9 J si raquotVudt j4 raquo ) IWHUM PariHl Praquogt^i-raquolaquo
FfctJL iirrcraquogt
IMi to to ON m C alaquo r c w i laf I fct laf ItonlSMT
FfcUX 11 rrr laquoraquoMMMI~
bullraquo laquobull IH aft i 4rflt ifctMijarr
bull7
bullJS maunutj I t 93 n r r r IFBJ 6jlaquoaraquo a hai laquobull
face ocal oadu laquo laquowieau of
I M laquo F v J 4 laquo ^
f i W t laquomajm awir loaae Iraquoraquo bull ulaquoaagt aavm tar rmttte mctmm of tar Maaak TW laquoaraquo-hlaquoir i i i i f m mt omtfutd raquoH w w n n MC-fraquoar pat-iarraquo atad ar m bar pml r i nraquo the | bullveil) at fafencaiMa)- Suit aifcaiettfaiamare i loth atatuicw M Fa 6J6 bgt the iafJMf t laquo mdashlaquopmm ukra gt4 oW 503 aajdaara 1W 503 laquofrltMMraquo J M K J M j i I5M C hai oaka iem tracks Ifiy 634raquo| feat laquoa a lacat arja aaaarealh Me to
ka4 a sfcvrt crer raatare life aha M a ^bullXM2laquo4hKk m l Mi fit my (filaquo J5 IL K M -
bullera m mm Sm mtomm (Fftj J4raquo|i h mm akv I thai aartee aacks bull jraiar fiw layer TW 114
I2MdegClaquoFlaquoJ$raquo)lt
the tenet 509 aaaatn (Fig 3Saraquo Hat layer tana) a e 53 mm 114 air-aafi
aa ie i t jn at II77C ai anjon
baen of i l aaa ltA0J raquo ) a w u t e m I at aacoad 617 after OlaquoCP tern at I W f C raquooraquo i r at bullraquo M a a OI I I I i n 500 pmm oBjaea- T V bet of cartwtci ai tar tarface lever any teae at tarn
in I U a laquoN1 i fcc ~ IW f f v i olt bull m bullbullbull ngt bull mp ttaatmdash ftuauwt l laquo a i i rlaquoWKftll~l raquofJaar 1731
617 M
+rnm
OTraquomm
ttm mOtOimTttrc am IMtMTC
growth m the 503 specimen (Fig 6 35| during the soMMwa mmtd h is Midear as to
certain tptcimrai haw the carbide-free layers 1 specimens were svoposedry fabricated in the
same way The malts of the mrtafcajraphtc and TBI lt
lion cannot be nsed to fnty explain the i which led to the early creep fnlnrc of two of the specishymens studied However we banc shown that a awnber of aticrostractaral inhoniofmirties exist in the 25t Ti asotified rLarloy N aftoys induding carbide-foe sur-face layer tnrft-grsia lint snrface hyers nmeratwd carbide strinnprs and nononifonn diHribniions of Mf-type carbide nor grain boundaries Some of these
ties appeared to affect the resnhs of tots and may also inflnence other hnpor-
snch as those renting to tclarium attack Consequently a stndy was initialed to prodace rtsstd-loy N aftoys with more homogenous nacrostradares
bull J J llinnnmiim UnmfJy H Aiayraquo
The problem of prodacing Hastdoy N alloys with hiuaugtmuui nacrostructures is being approached in two ways The first is to reduce the carbon content in the atoy to ensure that aR of the MC-type carbides are diaailvud daring the solution annealing treatment If all
the carbides could be held in solution daring fabricashytion the formation of carbide a ringers might be eKna-aated The second approach b a detailed evaluation of tbt fabrication process This latter effort is prwmily
at identifying the steps at which the different ae introduced and finding suitable
akemate processing methods to remove the anno-anajftiti A definite concern throughout the entire study is that any successful fabrication changes also be
immmiil practices The first series of experiments was
to cmnJnate carbide stringers by reducing the carbon content of the ahoy Thermodynamic takula-tions aung data from previous experiments indicated that aN of the carbides should dnsorve at I I77degC in aloys with carbon contents of less than OA45 wt 7 Therefore two aloys 451 and 453 both wtth a nomishynal lauteaoy N convocation (13 wt Mo 7 gtt Ct bal Ni) and 144 wl Ti were cast into l-m-omm marts having carbon contents of 0017 and 0035 wt 7 respectively The fabrication schedule called for the cast ingots to be hot swaged at I I77degC from a I-in to a 0430-in diameter and then to be annealed at I I77degC for I hr The rods were farther reduced o a 0 J37-in diameter by cold swaging annealed at I I77degC for I hr and cold swaged to raquo final diameter of 0250 in One-inch-long samples were then cut from each alloy rod
bull 9
encapsulated in quart urJer an argon atmosphere and aged at 7G0degC for 16-5 hr to precipitate the carbides After aging the carbides in alloy 453 (0035 C| were extracted clectrochermcally in a methanol 107 HC1 solution Consecutive extractions produced the profile shown in Fig 6 J 7 of wt 7 carbide precrpiuie through the thickness of the sample The profile for alloy 453 is considerably more uniform than those obserad for alloys 503 and 114 specimens aged at 750degC for 1000 hr The difference may not be entirely due to a reducshytion in carbon content because the 503 and 114specishymens were swaged from bars cut from i-in-thick plate not from drop-cast ingots (Carbides are fairly unishyformly distributed in the grain boundaries of the 2-lb laboratory ingots while they appear as stringers in the A-in plate) Meiallographic examination of the aged 451 and 453 samples (Fig 6 J 8 ) showed that the reducshy
tion in carbon content did not ehrninafe the carbide stringers However the stringers were liner and more evenly distributed than those observed previously (Fig 6J4o) Carbide-free surface layers were observed in both specimens a typical surface layer in a heavily etched 453 sample is shown in Fig 6 J 9 The depth of the carbide-free surface layer was V0U03 m
Fatifcpnwn One of the moat critical steps in fabrishycating tbtf^iioy N aRoys with respect to its effect on microstruciurr laquo the solution anneal Electrochemical extractions on an as-swaged alloy 453 (00353 Cgtsamshyple showed that a moderate number of carbide panicles (M) 2T) was present Hi the microstructure after procshyessing It a suspected that the sample was not adeshyquately annealed at 1177degC prior to the final cold swagshying operation That is the annealing lime was too short or the annealing temperature was actually less than
90
0080 O0TS FMQHOWTEtOF
X amy Mkif S03 JI 1177 f M lt jpee gti laquocopylt for
I ITTC Therefore the respuMe of tiUmum-mudifWd thneloy to sohnion aaandias at I I77degt ws stmfced as a fmctioa of time at temperature
Samples of aloy 451 |OJOI7 Craquo W anon at I IT7degC for 15 mm lo hr The cleaned etectrucheaacaRy for 6 hr to remove any nr-faoe effects ami the carbides were electrochemical extracted separated ami weighed The resatts of this experanent aw plotted m Rg 640 (My extremely
bullis of prcopitaies were present a samples for 2 hi or more At times less than 2 hr there
scalier m the data hat m geaerai chfHIv preopifc te was extracted These remits indicate
that JO to 60 mm are weeded m addition to the stanshydard 14 sohtiox anneal at 11 T T r to dtooKv the carshybides completely Muumaptu of tectioas from each of the samples r f aloy 451 from the first jaarmaj series are mown irgt Fig 641 Little gram growth was omened between the 154am and 14v anneals while mgbt grain growth was etideai after 2 hr at II77degC As expected rather extensive growth occurred at the longer j times of 4 and 8 hr
FfcnJB Wcwsmnmwof limn wimfml llsmliy N amyi451 jM7Cgt anl 4raquo IftWW O after coal maawwanl aanf at TMTCfbr I US fcr (laquogt Alloy 451 laquoAgt AHny 45 J
91
foert seed-
Abhoaeb most of ike effort m ties stedy hat beea pit wii be exammed mdashtuiognfkicjh before deeded towvd etmeeetioa of canede miegrn a the aflaquoer a soaatioa aaeri at 1177C I b j bull a bullloys enprrimdashrii aieafao mdashdet way to i i i f i i a n the iimiag eomt a t e mdash taebidr few b y m cjHeoftie carbide-free layersm oar experiment Bee- alnae ibr mdenrd irrliw nf
a w that n any effects of bet or cob) Y-133201 mmraquobemremoeedby
there is ike coaaderata eery bull fact be the bey to uioootaH a ahoy A aoajher of rchmvesy eeeor cheaats bull the way ibe eeecviel is leeeeed amy mwe oaaaaptK effects oa
4SI awi 453 aie ui l i l l aai wal be tnMcated to CiVideraquofiw]|Bmemmmmmmmmmmmmmml 025ampmemai rod with special attewtioa peel to the
CSl nOwal t h e W O f k HBOC l lHOWHKNVt the B I O O 0 B H K SO
J SALT COMtOOON STOKES
J R J R Difdkno E J Lawrence
by of
FbgtraquoJ9 i t u n a
453
The conoaoa of bow) asefcei-mniten ihtonac salts has ben the research for aemy years Resell seen as FeFj NiF and HF in the sah react with con-sliteeats of the alloys bet corrosion from these soartes a basiled by the seppiy of reactaets The strongest oxidant of the normal coaetiteeats of foH salt is UF 4 and of the major coastrteeets of most iron- am nkfcei-base alloys cbrommm forms the most stable fleoride Coaeeoeeetly the major corroajon reaction between
02 OftftJL-OWG 7 5 - 1 2 2 4 )
5
imdashimdashimdashr o 1st ANNEALING RUN laquobull 2nd ANNEALING RUN o 3rd ANNEALING RUN bull 4th ANNEALING RUN
2 3 4 5 TIME AT 1177 C (hr)
FfeSvMl AmcmMoliBAim$9tncmihomraquonor4Slmraquotmgtctomlt4Vmmmitioraquo
8
bullfii7rc
92
to) CM ltlaquogt
FltMI MkioaMjai of mdash bull I br kit 2 br laquoraquobullraquo 4 br jfld if) nr
i laquorf raquo r 451 aftw M M M Mlirrcfcw tol IS i ltraquogtMl ltrgt
nickel- or iron-base alloys and molten-salt reactor fuel salt has been found to be
2UF 4(dgtCrfc)^2UF(draquoCrFj(dgt
Because the equilibrium constant for this reaction has a small temperature dependence temperature gradient mass transfer can occur and results in continuous reshymoval of chromium from the hotter sections of a system and a continuous deposition of chromium in the cooler sections
The experiments described in this section are being conducted to determine the corrosion rate of various
sall-afloy systems under controBed test conditions The variables include compoatiou of the alloy oxidation potential of the salt temperature and exposure time Afl loops incorporate electrochemical probes to measure the concent ration of uranium and transilion-metal flushyorides The systems used to conduct these experiments include one forced circulation loop operated by personshynel in the Reactor Division and three thermal convecshytion loops Five additional thermal convection loops have been constructed and are being prepared foi effrj-tion The status of these eight thermal convection loops is summarized in Table 613
93
i l l l f lS
IA
raquo
raquo
tit
MRSkr
l l t e M JS
rN
it
h i
M l
laquo J I Fael M l
Two thermal convection loop NCL 2 IA and NCL 23 have been operating with M S W fuel salt iLiF-BeFj -T lr f^- lF M M 1 7 - O J mote ^raquo lo obtain baseline common data NCL 21A is a HasieOoy N loop with specimen of the same material At with a l thet-mal convection loops dghi specimens are inserted in the hot and the coid legs The 16 spedmens are reshymoved periodicaly for visual examination and weighing The results of the weight change measurements are shown in Fig 642 The corrosion rate of the hottest specimen in this loop is somewhat higher than has been observed in other rfasteUoy N systems (see Sect 682 discussion of FCL-2bgt The higher corrosion rale of loop 21A relaies to the relatively high oxidation potenshytial o( the salt in this loop ( U M about 10 I Horn-evei assuming uniform removal of material the corshyrosion rate of the hottest specimen was 024 milyear which is within acceptable limiis This loop will conshytinue to be used lo obtain corrosion data for Hastelloy N in kali with a relatively high oxidation potential
Loop NCL 23 is constructed of fnconet 601 and has specimens of the same material A loop was built of tnconel 601 because of this afieys resistance to grain boundary penetration by lefuriwn Since the alloy conshytains ZV Cr there was concern about its ability to resist attack by molten fluoride salt The corrosion rate of Inconel 601 in fuel salt was determined from weight measurements of the 16 spedmens of loop 23 and the results are shown m Fig 6 4 3 All specimens lost weight and the lost shown by the hottest spedmen w very large The material lost by the hottest spedmens did not result in uniform removal of the surface but resulted in the formation of the porous surface strucshyture shown in Fig 644 As shown in Fig 645 electron microprobe examination of this spedmen showed high thorium concentration in the pores The only known source of thorium was the salt which contained T h F 4 so it is very likely that the salt penetrated the pores Continuous line scans with the microprobe indicated a depletion of chromium near the surface Figure 646 shows the results of analysis for Ni Cr jnd Th This figure clearly shows the chromium concentration gra-
94
OMK-WH TO-IZZ4 1 1 1
0 laquo000 2000 JJ00 4O00 5000 SPECIMEN EXPOSURE TINE ltgt
Flaquo 642 Welaquoht campMfts of HasteBoy N p-ciaraquoeas fro loop NCL-2IA exposed raquo MSMt fad o k at the indicated tenMcnaMe
0OM-0VC T raquo - t laquo laquo 5
SPECIMEN EXPOSURE TIME (Hrl
F 643 Weht changes of Inconei 601 specimens from loop NCL-23 exposed to MSBR fad salt at the indicated tem-peratare
dient and provides further evidence of the presence of thorium in the pores Deposits such as those shown in Fig 647 formed on the specimens in the cold leg and the deposits were identified by microprobe analysis as chromium This compatibility test of Inconei 601 in MSBR fuel salt shows a relatively high corrosion rate and it is doubtful that this alloy would be suitable for use in an MSBR under the conditions of this test
The lower limit for the U ^ U ^ ratio in an MSBR will likely be determined by the conditions under which the reaction
4 U F + 2 C i r 3 U F 4 U C 2
proceeds to the right Because the salt in loop NCL 23 is strongly reducing with a U ^ U ratio of less than 6 it was decided to try to reproduce the results of Toth and
Gilpatrick1 wiuch predicted that at temperatures below 550degC and VV ratios below 6 the U t would be stable However graphite specimens exposed to the salt for 500 hr did not show any evidence of U C 2 The specimens used were made of pyrolytic graphshyite and it is likely that the high density of the material limited contact of the salt and graphite The experiment is being repeated with a less dense graphite
682 Fad Salt Forced Gmriatioa Loop
Hastelloy N forced circulation loop FCL-2b has been operated during this reporting period to gather baseline corrosion data under conditions where the i r U ratio was relatively low (see Sect 23) Eighteen itastel-loy N specimens were exposed to MSBR fuel salt with a U 7 U V ratio of aUut 100 The specimens were reshymoved at predetermined intervals for visual examination and weighing and the weight changes are shown in Fig 648 Six specimens were held at each of three temperashytures 704 635 and 566 eC Of the six specimens at each temperature three were exposed to salt having a velocity of 049 msec and three to salt having a veshylocity of 024 msec No -ffect of salt velocity on the corrosion rate was found so each data point represents the average weight loss of the six specimens The weight loss of the specimens at the highest temperature correshysponds to a uniform corrosion rate of 011 milyear Uniform corrosion at this rate is acceptable and well within the limits which can be tolerated in an MSBR
Following termination of the ^3200-hr corrosion experiment FCL-2b was to be used to make heat transshyfer measurements This operation has been delayed because a salt leak developed and a section of the W-in-diam Hastelloy N tubing had to be replaced (see Sect 23) Examination of the tubing in the vicinity of the leak is under way
Further corrosion measurements will be made in this loop with the U7U ratio at about 10 Additions of N i F 2 traquo the salt will be made to raise the U ^ U 3 ratio to the desired level
683 Coolant Salt Thermal Convection Loops
Thermal convection loop NCL 31 is constructed of type 316 stainless steel and contains LiF-BeF2 (66-34 mole ) coolant salt The 16 removable corrosion specishymens are also nude of type 316 stainless steel The maximum temperature of the loop is 639degC and the minimum temperature is 482degC The initial objective of
I I L M Toth and L O Gilpatrick The Equilibrium of Dilute UP Solutions Contained in (imphite ORNL-TM-4056 (December 1972)
95
_o o
tvri O
o O
-o d
FtJ 644 Microfracture of Incoad 601 exposed lo MSBR fad sah al 704 C for 720 hr As polished
Y-1312W
BackscoMered Electrons ThMc X-Roys
Ffc 645 Electron beam scanning image of Incond 601 exposed lo MSBR luH tall for 720 br al 7 0 4 C
HImdash3000 COUNTS FUU SCALE Ctmdash3000 COUNTS FUU SCALE THmdash000 COUNTS FUU SCALE
~~1
Y - 1 3 1 2 1 9
I L i JLJJJ - mi
Ffe 646 Mfcfopnbe ctmtimomi K M K M M M corroded ana in IMCOMI 601 exposed io MSMt M salt for 720 hr at 704deg C
97
Fij 647 Microstnctare of lacoael 601 exposed to MSraquoR fad alt at S66degC for 720 kr As pofohed
cobalt-base alloys is being evaluated in the unstressed condition in the TV A Bull Run Steam Rant Two heats of standard Hastelloy N tubing (N1S09S and N1SI01) are being evaluated in the stressed condition from 280 X 10 to 770 X IO Jpsi
The method whereby the specimens are stressed is shown in Fig 649 The wall thickness of the gage secshytion of the specimens was varied from 0D10 in (77X) X 10 psi) to 0030 in (280 X 10 1 psi) to produce the desired stress range The raquo-in-OD capillary tube conshynects the annulus between the two tubes to the conshydenser When the inner tube ruptures steam passes through the capillary and a rise in temperature of a thermocouple attached to the capillary indicates rupshyture Time to rupture can be taken directly from the multipoint recorder and plotted vs sfess for design purshyposes Data of this type for periods as long as 11000 hr were reported previously17
A photograph of the specimen holder (Fig -gt0) shows the ten instrumented stressed specimens the four uninstrumented stressed specimens in the filter basket and the unstressed sheet specimens bolted to the speci-
12 B McNabb and H E McCoy MSR Program Semiarmu Progr Rep Feb 28 1975 ORNI 5047 pp 94-101
OJKM-0W4 TS-lt22laquolaquo
O 500 IO00 ISOO 2000 2500 3000 3500 SPCCIMEN EXPOSURE TIME (hr)
Ffc 648 wetgtt changes of HMCHOY N from loop FCL-2b exposed to MSBR fact salt at die Minted temperatare
this loop is to provide baseline corrosion data on a comshymercial iron-base alloy The loop has been in operation for 248 hr
69 CORROSION OF HASTELLOY N AND OTHER ALLOYS IN STEAM
B McNabb HE McCoy
The corrosion resistance of several heats of standard and modified Hastelloy N and other iron- nickel- and
98
OB -OK M - 3
STEM SUPPLY 99ooplaquomgtr
t laquo - IT raquolaquobulllaquo
C t f U M V f TUBE
TUBE BURST SPECIMEN (TYP 10) WATER OUT
RETURN TO CONDENSATE STORAGE
f 649 ScfccaMtk of dostfe-watcd tobe-barst eciam
men holder The filter basket bolts to the small flanges on each side of the sheet specimens (shown exposed) so that the specimens are covered and the flow of steam is uirected over the specimens rather than around them The steam enters the specimen chamber near the middle of the stressed specimens in front of the unstressed specimen holder and is directed lengthwise over the two stacks of 2-in-long X H-in-wide X 0035-in-thick sheet specimens The steam passing over the specimens flows through the Neva-Clog filter to prevent scale from entershying the flow restricter orifice or the remainder of the steam system The steam is condensed and relumed to the condensate storage vessel No specimen has lost any scale so far but some of the Croloy-type alloys are beginning to develop blisters a prelude to scaling The oxide on all HasteUoy N specimens is thin and adshyherent with no evidence of scaling Some of the unshystressed Hasteiloy N specimens have been exposed to steam for 19000 hr at 538degC and 3500 psig Several alloys were included in this study andas reported preshyviously 3 they displayed a wide range of oxidation rates Several obeyed the parabolic rate law Aw = Kt0gt where Aw is the weight change in mgcm 2 r is the time in hours and AT is a constant Figure 6SI is a
log-log plot of weigh change in mgcm as a function of time in hours Note the sudden increase hi the rate of weight change with each alloy gaining approximately 05 mgcm z over the last 4000 hr This probably indishycates deposition of some substance on the specimens at a rate that was equal for all specimens We noted preshyviously that fine particles of iron oxide that was enshytrained in the steam had deposited on the specimens but this deposition occurred at a much lower and conshystant rale
The increased rale of weight gain for bulllaquo specimens was discussed with Bull Run engineers The Butt Run facility has had several instances of condenser tube leaks in the last year of operation whereas in previous years few if any condenser leaks occurred The cooling water in the condensers is at higher pressure than the condensshying steam to prevent back pressure on the turbines and when a leak occurs untreated cooling water is introshyduced into the steam system hot wed Continuous monitoring of silicon in the four hot wells (condensed
13 H K McCoy and B McNabb Common of Seven fron-md SirkelBttr AUoyj in SMptnrihctl Steam tt IWmfF ORNL-TM-4552(AupB( 19741
99
yen ttSO fhnnnif of MM M H mwooaw dumber attar I9JBM hr of ixpamdashJI Fntaro to note ire the ftrcacd D M mcmlnMnmicd iptcimem m ihr fitter Iforeiivimdl the two grown laquo f umtreued ipecanens and the tea nwuaacMcd tfrcued iptnanm The Miem-rf ltrcanem haw an oniadc domclcr at I in and a length of 3 in
steam wdfc) indicates a condenser leak when the silicon lewd increases and the leaking condenser can be isoshylated and repaired The condensed steam (and any coolshying water mtrodticed by condenser leakage) poses through demineahzrrs and is ntonitored again with silishycon and other irapuifies being held below acceptable broils before the condensate is returned to the steam system Even though care is taken to prevent excessive amounts of imonritres in the steam system the farihiy is evidently opt rating with a different level of impurities than had been experienced before condenser problems developed Some evidence of indium shkate as a Mack-Mi gray deponihas been observed on some safety-valve seats and this is poanoty the material that has deposited on the specimens The oxide on most of the specimens is Mack or gray and no changes in i u appearance were noticed during routine examination and weighing of the
specimens When the specimen holder is removed for the next scheduled examination an effort w i l be made to determine the composition and nature of the deposit
by Bofl Run engineers in the near future to ehrninate the problem of condenser leaks
Some of the aloys represented in Fig 651 lost weight inriiany before gaming at an accefcaraied rate during the last 4000 hr These alloys were Hastetoy X ttsynes alloy 188 and rnconel 718 and they contain approximately 205 Cr Other juvestigstors have reshyported weight losses due to loss of chromium in steam at high temperatures I i is probable that these aHoys would have continued to lose weight if the steam conshyditions had not changed new specimens of some of the aloys WW be inserted in the lest facility when sieam conditions improve
MS
t I t OBSERVATIONS OF REACTIONS IN METAL-TELLURIUM-SALT SYSTEMS
J Brynestad
Several criteria must be met for a good screening test system for the teflurium corrosion of Hasteloy N
1 The teflurhun activity must be appropriate reproshyducible and known
2 The tefflurium must be ddivered uniformly over the sm|jie surfaces and at a rate sufficient to prevent excessive testing times
3 Preferably the system should operate under invarishyant conditions during the test run
4 The system must be relatively cheap simple and easy to operate
in the MSBR the production of tellurium per time unit wnl quickly reach a constant value and in due time a steady state will be reached where telurium is reshymoved from the melt at a rate that equals the rate at which tellurium is produced
i to reacting with me Material of which the circuit is constructed leBunum could be reshy
moved by several means which mdmfc the foetamug
1 The | ining system Since the MSBR is to be equipped with a pm ceiling system to remove Gemm product telufium might be effectively removed from the salt by appropriate measures
2 The gas phase If the gas phase is contacted with a getter such as dumnium wool the tchwrimn activity m the men ought be kept dose to that defined by thelaquo
^Cr TTe(k)^ TeltgH ACrlts)
Thu activity is sufficiently low that Hastdoy N would not be attacked
3 A getter immersed in the salt mdt Obvious disshyadvantages of this arrangement would be the probshylems of mass transport in temperature gradients and the lack of a candidate material
Until the steady-state condition in an MSBR is more dearly defined it is impossible to state the likely tellushyrium activity It is only known that in the MSRE stanshydard IfasteOoy N was embrittled (probably by tellushyrium) In the MSRE the steady-state tellurium activity - if ever reached - probably was defined by gas phase removal and was likely rather high
Until the steady-state situation in the MSBR is deshyfined it must be assumed that one must deal with the MSRE condition under which standard Hastdloy N is embrittled In order to define this condition we have tested several systems with defined tellurium activities with regard to their behavior toward HasteHoy N
1 equilibrium mixture of C^Tejfs) + CrjTe4(s) 2 equilibrium mixture of NijTej(0j 41 at 7 Te) +
NiTe 077J(7I ^ 437 at Te) 3 equilibrium mixture of CrjTe 4(s) + CrTc6(s) 4 equibbriun lixture of Ni 3Te(s) + Ni(s)
The systems are arranged in sequence of decreasing Te 2
activity as determined by isopiestic experiments Typical corrosion experiments were contacted at 700degC for 250 to 1000 hr The arrangements were by isothermal gas phase transport of Te in previously evacuated sealed-off quartz ampuls by embedding the specimens in the mixtures and in the Cr2Tej-CrTelaquo and CrjTe4-Cr4Te6 cases by transport in molten salt
The most pertinent results are as follows
I Hasldloy N samples exposed to NiTej(s) bull Ni(s) (system 4) did not show intergranular cracking This is promising because if one a n establish a steady-
M l
dak luaawiun m which the telahaa activity is kwcr HOT OOI aefaed by das system staadanJ Haacaoy N wtl wot be eaaaittled
2 Sysaeas I awl 2 have teMaaa activities thai are loo high Ibex sysseas corrode Hasseaoy N sevcaeh water af the experiaeatal w w y a w i aad
3 Systea 3 fCrjTelaquolts) + CrTeraquoltsti SIUHH proaase as a iraariaa-deaivery actboa a aohea sansacc it B saffvseatry corrosive to cane aterpawatar cactoag of thk-caoy N b a docs aot fora acactioa layers
It is of value to note dot the systea Cr7Te(s| bull Ctls) has a tehaiaa activity that B mar lower thaa the systea NiTe2(s) fifs) l as systea abo is proa-isag since lagh surface duoaaaa aiebt be used a a tdariaa getter a the fas phase Experiments are water way to measure the telariaa activities of the above systems
611 OKRATIONOF METAL TEJXURJUM-SALT SYSTEMS
J R keissr J Brynesud J R DiStefaao EJLawrcace
The discovery of Jtatk intergranular cracking of HasteBoy N parts of the Molten-Sail Reactor Experishyment which were exposed to furl salt led to a research effort which identified the fission product tellurium as the probable cause of the cracking Experiments showed that HasteBoy N specimens which had been dectro-plaied with tellurium or exposed to telariaa vapor exhibited shallow intergraniaar cracking like that of specimens exposed in the MSRE Subsequently a proshygram was initiated to find an alloying modification for HasteHoy N which would enhance its resistance to teiu-rium The resistance of these modified alloys to crackshying is measured by exposing specimens to leaiirium vapor deforming them and then evaluating their surshyfaces by metallograpruc and Auger methods However the chemical activity of tellurium in these experiments raquo significantly higher than it was in the MSRE In order raquoo simultaneously expose specimens to the combined corrosive action of molten fluoride salt and telurium at a more realistic chemical activity a method is being sought for adding tellurium to molten salt in a manner that would simulate the appearance of lefurium as a fission product Experiments have been started that wia permit evaluation of several methods to determine whether they will produce the desired conditions
61 II Teaaraan Expcnacatal Pal I
Tellurium experimental pot 1 was built to evaluate the use of lithium telluride as a means for adding lefu-
riaa to safe Has pot laquoRg 632)aVws t d a a a lobe
BaaaaWC PJKBTBBH t a W t m a f f e a l tan a a r a n f H M K I BBBEBY a a a V aj w^ laquo ^ n i w araquovraquo ^ ^ p a t s waaaaajaa ^^a avaa BPUiawavww a a wuvu a a a i aaawaa
through Tefloa seals aad are used Or delect aad aeaa JK
14 The Nrtimdash laquo fan far As nacnacw raquo raquo fnfmt4 bully vannr t JHB ncaacny i mc ootiiuuucvKai B a M i i o o bull a t m4t traquo aryci raquo4 ) b M r
102
I bull UF-lef -ThF 4 (72-16-12 mdk mi m tern- A rfastetoy N pat was filed with the salt LiF-ftcfV latoSOTC ThFlaquo (72-16-12 aaok ) mi the temperature conshy
trasted at 700C After a sample of the salt had been lixTe which w pscpMcd hy the tafcea CrTelaquo was added mi a M I Hasteaoy N sheet
(Sect 31) hat i i i j two pdhsts specimen was inserted hMo the salt After 170 hr the a total of 0170 g of l i jTe were added to tjrrrwnrn was reamed and after 250 hr a salt simple
I of saw taocaoJwwkji enmamiua of the salt wax taken The teaaperatare was thea lowered to 650degC of oar ftadynra Chtaaitijr Draw gave aad a day user a sab sample was again takca This of the preseace of irlmiiia (Sect S3) xoacace was thea repeated at 600C Next the salt
dace aancIiiTepdkts west added aad te-ptrataie was rawed to 7O0C Cr Te was added a sawffc of Ae salt was takes for choanal analysis aad aaother Hastetoy N spedaaea iasertcd Ihe sped-Thre- addaaoas of CrF 2 totaling IJ2 g were thea a n was reasoned aad sah samples were tafcea under the aanle roauaed hy the aaaaaoa of theee awe li jTe same tjaw4eaagteratare coaditioas as discussed abouc
A anal iddirtja i nailing of 02 g of 10 was The two Hasteloy N spediaeas we submitted for Anger examination No were detected bat twdeace of tdariaai in the grain
foaad (Sect 612) The results of thr of the salt snaade are shown in Table
614 Tcaaraaa ooaceatratioas at 700C were not as bjgb as was expected bat the tact that some tct-irium was ia solution is deaaoastiated by the teHariam found oa the tpniannt Addrtioaal CrjTe was added to the
two salt samples were take lYriincaary that the soJatioa any not lane been
i the first series of salt samples was ulten the solafcarry measurements two tensile
icre exposed to the sah-CrjTcj solution Both specaaeas oae of rcfabr Hastcloy N and oraquo of lift Mraquo-07 Ti uwdrfied Hasteloy N showrd a
after 500 t_r exposare at 700C After iheregabr Hastetoy
N jpuinun was obatmd to lane agaificaatty more aad cracks than dhJ the modified Hasteloy N sped-
i (Sect 614)
r6M
611J
The adfciua of a CrjTty or CrgtTlaquo4 at anj stall aaothtr awaVod for
toaHaamMSMfanadtiraaesceai of ehraawam idhaldt is bullanafaajsi aat acttwiy of
at the adt wM he otnunaat pro-
To at which canter of thaat chro-
bullw wWwWwaPpPIbull VraW) ^ppaaar bull ajwPTff
of the chromta Mftaridat as s faac-
Tlaquoaa rnmauddNoanan M )
Moaa^aVStwMw bullnoTci After
OTe After
Ctlt tUHiam
im Tlaquo 5 0 4 4
Tlaquolt5 Cr7S
Tlaquolt5 CrlaquoJ
656 Tlaquo 151 CrIOS
Te75 Crl20
tan Tlaquolt5 rr
Tlaquolt5 OBJ
103
The experimental assembly is being used to expose standard Ifasteiloy N specimens to salt containing Cr Tej to obtain data on the extent of attack at 700degC as a function of time
611J Telwnum Expctunxwtal INN 2
When a technique for introducing telurium into salt at an acceptable chemical activity has been developed a method will be needed for exposing a large number of specimens to salt-tellurium solutions A Urge experishymental pot has been constructed for this purpose The pot has a stirring mechanism facilities for introduction of electrochemical probes and sufficient accesvi to allow dmulianeous exposure of a large number of specishymens Operation of the system will begin when a satisshyfactory tellurium addition technique is available
612 GRAIN MUNDARY EMHtlTTLpoundMENT OF HASTELLOY N BY TELLURIUM
R E Clausing L Heatherly
Auger electron spectroscopy (AES) is a powerful technique for studying grain boundary embrittlement of Hasidloy N by tellurium The recent development of the technique to permit AES analysis win a small-diameter (--5-fi) electron beam to excite the Auger elecshytrons of a specimen surface has made truly microscopic analysis possible1 5 The development of techniques for scanning the beam and the development of electronic data processing equipment have continued to be a censhytral pari of our efforts As the techniques improve our ability to see the details of the telurium embrittlemenl process improves dramatically We can now not only provide a qualitative image of the elemental distribution on intergranular fracture surfaces at a magnification of several hundred limes but we can aho provide a semishyquantitative elemental analysis as the beam it scanned along a line across the sample However it is not presshyently practical to provide a quantitative analysis along a line across an rntergranubr fracture surface since Auger intensities at each point OR a rough surface vary accordshying to topography This effect can be corrected in prinshyciple by a normaliation technique but data for each point must be normuhad mdrvKJuaRy and the present equipment cannot handk the volume of data required The data presented below are typical of several samples of lefluriurn-envbrittled HnHcRoy N that were examined recently These samples are being studied in various
15 R I ltlMlaquonf ami I Ikjihrrly VWT ftn^wm Srmi mmu rmtr Rrp fth J bulllt ORNI -5ltM7 p MM
pans of our previowtty outlined efforts to understand the tellurium embrtttkment of nickel-based alloys The sample chosen for the present discussior demonstrates our state-of-the-art capabilities and limitations and at the same time provides some new insights into the nature of the tellurium embrittlement of Hasteloy N
A sample of Hasteuoy N that had been exposed to tellurium vapor at low partial pressure for SOO hr at 700degC was fractured in the AES system and the resultshying fracture surface was analyzed using Auger electron spectroscopy The fracture surface is shown in Fig 6 3 3 The scanning electron micrographs made by Crowe reveal that intergranular fracture occurred along the edges of the sample and that the central reejon faded in a ductile manner One fairly large area of ductile shear can be seen Three types of Auger data presentations are used below imaging line scans and selected area analyses The first is qualitative while the second and third are progressively more quantitative
Figure 634 is an image obtained using the scanning beam in the AES system and the absorbed sample curshyrent to produce the image contrast It is similar to the scanning electron micrograph (la) but because of the larger electron beam and the different method for proshyducing the image contrast the resolution in Fig 654a is poorer and some distortion is evident Nevertheless it is relatively easy to correlate the features shown in Fig 634a with those in Fig 633a Figure 6346 is an image of the same area shown in Fig 634a but with image contrast produced by the tellurium Auger signal A careshyful comparison of the areas of high tellurium concentrashytion with the areas of intergranular fracture shows that a good correlation exists between the two No telurium can be detected in the regions of ductile or shear fracshyture Figure 6 3 5 b a series of line scans showing the peak-to-peak intensity of the Auger rignah for nickel molybdenum chromium and tellurium as the electron beam was scanned along the path shown by the bright line Hi Fig 654a Some of the observations that can be made are (I) The intensities of the Auger signals are influenced considerably by topography that is some features such as the shear region between feature gt and the ieRuriumlaquombrittled region below it show lower Auger emission for al dements (this dependence on topography accounts for much of the jagged nature of the line scant 12) The lefurium concentration is quite high in the region of mtergranuiar fracture near each original surfaor ltJ| There is a definite tendency for the concentration of molybdenum to be higher in the regions of intergranular fracture (41 The nickd and chromium concentrations are in approjumatety the same ratio throughout the scan
104
ltaraquo 2nox ifrgt sonx laquorraquo nmraquolaquo wgt torn lto jonox Tt
105
Y-133510
Crack
Te Ertrittled
I i raquo i gt MICffOftS 375
j j TTT90raquoi i i S i i i r r i I005 INCHES 0015
F fcM MI l i w u i rtmw bull laquo raquo laquo gt mm to raquo AES Fht brnrfii wiiiul law dnraquoraquo the path irf ibr IMW laquo M 4laquol HJaMMrt ftftom in laquo fc-35 (M h M p e f otoMawajgiMM
NJ 4t M M n Aapjf bull bull bullgt pMaJwt nartmrt The onkriiiM fraai tuwJjiy ngtam m i to th
106
Traquo-laquo4T
Flj tSS Anger ajnJ Menrities for scans atony Ike path wdicXcd sn Fjsgt 6S4 The vertical axis is displaced and the vertical scales arbitrarily varied to permit a qualitative comparison of the variations of Ni Cr Te and Mo as a function of distance along the scan line The tones and features identified along the horizontal axri are also identilied in Fig 6_S4raquo and c The AES analysis of the regions bbeied area I area 2 and area 3 are given in Table 615
Another observation based on the detailed examinashytion of this and other samples is that the tellurium conshycentration hi the grain boundary is not a monotonically decreasing function as one proceeds inward from the original surface On nearly all of the embrittled samples examined thus far the tellurium concentration is uni-formnJry high throughout the embrittled area as for example is shown on the right in Fig 655 (The signal intensity on the left is strongly influenced by toposhygraphy- If this effect were removed by a normalization process Ms area would have a more nearly uniform composition similar to that on the right) The high relashytively uniform telurium concentration in the embrittled regions suggests that either a particular grain boundary phase of fixed composition may exist or that the tellushyrium atom fill all of the appropriate grain boundary sites in the embrittled region Sputtering this fracture surface (and those of similar samples) to a depth of a few atomic layers (3 to 10) reduced the tellurium conshycentration to below I at showing that the tellurium is concentrated very sharply in the grain boundary it is
therefore unlikely that the tellurium present in the grain boundary exhibits the properties of a bulk tdluride The molybdenum concentration remained high during sputtering operation indicating that the concentration of molybdenum is high in the bulk phase perhaps in a phase that has precipitated in the grain boundary
Table 615 shows quantitative selected-area analyses made in the three regions of the sample indicated in Fig 654c The compositions have been normalized to equal 100 at in each row The three rows for each area are obtained from one Auger spectra but some elements were ignored in the first two rows to make changes in the relative amounts of the other elements more obvious These results confirm the above conclusions and show ( I ) that tellurium is present in relatively large amounts in the embrittled regions and (2) that area 3 which is near the extreme of the depth to which the tellurium penetrated contains about as much tellurium as area 2 which is located near the center of the upper embrittled region Regions 2 and 3 are both enriched in molybdenum and carbon M indicated in the line scans
107
r4IS Cuaiummnofi ofaHamdmyNa
tor Suffer at 7 laquo r c
Rezwn Composition in laquo5r
Ni Mo Ct O
Composition in the lower repon area 3 imiertranitU fracture)
Cohipositioi in ocntral region area I (dacine lnlaquoiuregt
Composition in ike upper repon arcs 2 imlergwiutar fracture
70 1 11 M 1 10 9 40 II 6 6 75 16 9 75 16 9 61 13 8 64 25 12 58 23 II 8 42 17 8 6
33
13
I I
Areas identified in FBJ 6-54r The composition in each row is normalized lo cquai 100 at ri The three rows
lor each repon are from the same data but are normabted so as to make changes bulln retain amount of the dements more obvimn For convenience and consistency in repot inc data we astame the AF5 spectra tfaol Pabnbetf et aL Htndhook of Anger Electron Spectroscopy Physical Electronics Industries Inc Fdiru Minn I972l are accurate and directly applicable to our data Elemental sensitmwes are taken directly from the spectra presented m the handbook with no attempt lo correct for chenaca effects line shape matrix effects escape depth or distribution of dements as a fraction of depth in the sample The analyzer used is Varian model 981-2707 operated with an SOOOeV electron beam energy
The above results suggest the need for a detailed examination of the causes and effects of the high moshylybdenum and carbon contents in the grain boundary region and abo an examination of the irnphcations that the presence of a two-dimensional tellurium-rich grain boundary phase may have on the time dependence of tellurium penetration into the alloy
613 X-RAY IDENTIFICATION OF REACTION PRODUCTS OF HASTELLOY N EXPOSED TO TEIXimiUMCONTAlMNC ENVIRONMENTS
D N Braski
Hasteiloy N and several modifications of the alloy have been exposed to tellurium to determine their rda-ive susceptibilities to intergranular cracking Different nethods for exposing samples to tellurium have also
been studied in an attempt to develop a suitable screenshying test for the alloy aVvctopmenl program Some specishymens were exposed directly to tellurium vapor at 700degC while others were subjected io attack by nickel or chromium teBurides at 700 and 750V respectively This section presents the results of x-ray diffraction analyses of reaction products producerl during the tests Knowledge of the reaction products akts in evaluating a
given method of tellurium exposure and may provide information relating to the mechanisms of intergranular cracking
A number of Hastefloy N tensile specimens and flat x-ray samples were exposed to tellurium vapor at 700 SC for 1000 hr in an experiment conducted by Keimers and Valentine The specimens were positioned in the top portion of a long quartz tube having a smal amount of teiurium at the bottom The tube was evacuated backfilled with argon and placed hi a gradient furnace with the specimens at 700C and the trtiiium source at 440C With this arrangement teuurium vapor diffused upward through the tube at a rate dependent on the temperature difference between the specimens and the tellurium CM)Xgt5 mg TehrV At the end of 1000 hr exposure the specimens were covered with a very fine hairlike deposit similar to that observed previously in creep tests at 6 5 0 C 7 The results of x-ray diffraction analyses on these deposits are given in Table 616 The first alloy listed is standard Hasteftoy N while the other three have titanium and niobium additions The main
16 A D Keimers ami D Y Vatentme MSK Ammjm Semi IMII rrogr Rep Feb 2S 1975 ORNL-5047 pp 40 41
17 R F GeMhach and H HensonMSK hvpmm jViinwm frogr Hep An J I 1972 ORNL-4832 pp 79 86
108
TaUcfclt X-faydifTrartiMi malts fori IO0O brat 700 C
Hat number t lt aftoyinx
additions to nominal HasteBoy N composition
Method of tellurium expovire
Surface reaction products
405065 None kelmervVaknime experiment^
NiTe CtJe
472-503 M r Ti kctroerv Valentine experiment4
NiTe
470-835 0711 Ti 261 Nb Kebners-Vakn line experiment
NiTe CrTe
IK) 841 Nb Kdmers-Valeniine experiment
Ni rTe
474-533 201 Ti Brynestid low Te ac irrily exposure NiTets) + Nitsgt
NiTe unidentified substance
405065 None Bryncstad LiO + CrTe
N i T laquo + N i T e
V D Kdmersaad D Y ValentineMSR Fran Srmunnu Prop Rep Feb 28 1975 ORNL-5047 pp 40-41 J BrynestadVSR Prognm Senaamu Prvgr ltep Feb 28 1975 ORNL-5047 p 102
reaction product was NijTe 2 which was detected on the surfaces of all four alloys (NijTe was found on earlier samples exposed for shorter times in the same apparatus) X-ray lines which could be indexed as CfTe4 were also found on standard Hastelloy N and on the alloy modifkJ with 071 Ti plus 263 Nb The Cr jTe 4 interplanar spacing and relative intensities were calculated by H L Yakel Metals and Ceramics Divishysion from the crystallographic data in ref 18 The presshyence of CrTe4 in the reaction layer is reasonable beshycause both chromium and tellurium were detected pre viously on Hasteiloy N exposed to nickel telluriddes by electron mkroprobe analysis1 In addition chromium tdlurides were previously identified by x-ray diffraction on Hastelloy N exposed to tellurium vapor17
Brynestad20 exposed 2 Ti modified Hastelloy N specimens to a low tellurium activity (Ni3Te + Ni mixshytwe) at elevated temperatures The specimens were first placed in a quartz tube and the Ni JTe 2 + Ni powder mixture packed around the specimens The tube was then sealed off under vacuum and placed in a furnace at 700degC for 1000 hr The reaction products obtained in this test also contained NijTe2 but the remaining four lines could not be satisfactorily indexed to any of the
18 A V Berfaul G Rnull R Aleonard R Pauthcnct M CVvTctou and R Jansen Structure Magnet iqucs de CtX 4
raquoX = S SeTeh Phvs Radium hi)582 95 (1964) 19 D N Braski O B Cavin and R S Ctmae MSR Prltt-
gnm Semtannu Fmgr Rep Frh 28 1975 ORNL-5047 pp 10$ 09
20 J BryncMad MSR Program lemktnnu Pmtr Rep Frh 28 i975 ORNL-5M7 p 102
Ni Cr or Mo tellurides The unusually broadened x-ray diffraction peaks suggest that a complicated teluride such as Ni-Cr-Te may have been formed In another tellurium experiment Brynestad exposed a standard Hastelloy N tensile specimen to a melt of LiCI containshying Cr 2Te 3 (solid) at 50degC Some Cr 2Te dissolved in the LiCI melt and reacted with the HasteUoy N After 146 hr the tensile specimen was removed and the flat surface on one end was analyzed by x-ray diffraction The results (Table 616) showed that Ni3Te2 and NiTe0 were produced
In summary these tests have shown that the primary reaction product between Hastelloy N and tellurium near 700degC is NijTe X-ray lines corrsponding to Cr iTe 4 were also present in patterns from the surfaces of several Hastelloy N alloys exposed to tellurium vapor at 700degC Exposure of Hasteiloy N to tellurium at low activities (NijTe2 + Ni mixture) may have produced some complicated Ni-Cr-Te compounds in addition to NiTe2 as evidenced by the unusually broadened x-ray lines
614 METALLOGRAFHIC EXAMINATION OF SAMPLES EXPOSED TO
TELLURIUM-CONTAININC ENVIRONMENTS
H E McCoy B McNabb J C Feltner
Several samples of modified Hastelloy N were exposed to tellurium-containing environments They were deshyformed to failure at 2SdegC a procedure v-hich forms surface cracks if the grain boundaries are brittle a
109
metallographk section of each was prepared to detershymine the extent of cracking- These tests hawe two objecshytives The tint is to dewlop a method for exposing samples to leBurium to produce a reaction nte comshyparable to those anticipated for an MSBR This rate is thought to be a flux of teOurium of about I0 1 atoms cm 1 sec- The second is to compare the cracking tendencies of arious alloys of modified HasteBoy N
A new technique developed for measuring the extent of cracking is more nearly quantitative than that used previously In the new technique a mounted and polished longitudinal section of a deformed specimen is viewed on a standard metallurgical microscope The eyepiece has a fiar which can be rawed to various locatiom in the field being viewed The filar is attached to a transshyducer which produces an output voltage that is a funcshy
tion of the location The output signal is interlaced with a scull computer which WH on command compute crack lengths and several statistical parameters The information is displayed on a teletypewriter The cracked edge of the mounted specimen is scribed every 01 in_ and the operator measures a l cracks in successhysive 01-in intervals untl at least 30 cracks have been measured The computer then calcinates and displays the average crack length the maximum crack length the standard deviation and the 95- confidence interval A typical scan requires about 10 mm and is considershyably faster than other methods used thus far
The experimental conditions associated with the ten experiments to be discussed in this report are summashyrized in Table 617 The chemical compositions of the alloys studied are given in Table 618 In all cases the
T J U T pound I 7 Cenoal4cxiiftmm ofTe-HaMenoy N a y w t t
Experiment IXcsipna (km Experimenters Exposure
conditions Alloys
bullMinded Genera
75-1 Brynesud UCl + Cr Te for I 4 6 n r a l - 7 5 0 C
405065
75-2 Krimcrs Tc vapor for Valentine |l)00 bral 700 C 405065
470-835 472-503
ISO
75-3 Bryneslad 250 hr at65ITC 405065 pa-kedin( r Te 474-534
474-535
75-4 Bryncstad 200hraf 700 C packed in Cf Te
405065
75-5 Biyncstad 504 hr at 700 C 405065 Keiser in s i t bull Cr Te 470-R35
75-6 Brvnestad 000hra l700C with vapor above Cr Te 4
405065
75-7 Brvrrslad 1000 hral 700 C with vapor above Cr Te
405065
75-8 Brynestad 1000 hr at 7 0 f l T laquo i l h vapor above J gt nH-kel tellurides
405065
75-9 McNafcb 250 hi al 7laquofC in 405065471-114474-534 McCoy vapor above Tc al 474-5356006006263
300 C I H 237295 297 298 303305306345346 34734821543469-344 469-648469-714470-786 470-835
75-10 McNabb 250hra l700 C in 40506521543 345348 McCoy vapot above Te al
300C 4 1 1 4 1 laquo21424425
Heavy reaction lay en
Whisker growth evidence of inhomopenoas reaction withTe
Heavy reaction layers
Heavy reaction layer
Reaction layers
No visible reaction ayers
Shallow reaction layers
No visible reaction layers
No visible reaction layers
No risible reaction layers
See Table 618 for chemical compositions A D Kilmers and I) Y Valenlnc M$R Program Srmimmi FriffT Kip Feb -X V75 ORNI-5047 pp 40 41
110
t6lt
Heaimoabei Mo Cr Fe Ma C Si Ti Mb At Of her
62 134 752 a 020 0042 001 a 19 63 145 7 J 3 a 020 0135 001 a 25 l raquo 12 70 0040 022 0046 OJOI lt002 184 ISI IS 684 0054 0-23 045 001 050 185 003 W 237 20 67 43 049 0032 m 004 103 lt0-05 295 14 806 402 0 28 0057 lt002 lt002 085 0 0 5 296 15 809 396 028 0059 lt002 lt002 12 02 W 297 29S 303
2 1 20 20
70 70 70
40 40 40
02 02 02
0 0 6 006 006
002 0J02 0J02
024 lt00I
049
057 2J0 0J4
305 12 825 416 022 0072 009 088 I J 306 06 804 311 018 0065 027 001 OSS 345 IJO 71 38 026 005 022 002 045 346 110 67 37 018 005 048 002 049 347 20 7 43 025 005 047 lt002 088 34S 411 4 l i 42 424
20 20 20
120 120
72 70 70 70 70
007 a a a a
019 02 02 02 02
005 005 005 005 005
047 e a a a
lt002 a 1 0 219 18
042 115 113 104 134
007 010
42J 120 70 a 02 005 a 19 048 008 405065 160 71 40 055 006 057 lt00I a lt003 472-503 129 679 O089 lt00I 0066 0089 216 005 009 471-114 125 74 0062 002 0058 0026 175 a 007 474-534 1166 712 006 lt00I 008 003 20rgt a 053 014
0013 La 474-535 1179 730 005 lt00I 008 003 213 a 055 010 W
0010 La 003 Cr
600600 160 80 019 027 ltlnconcl600gt 469-64 128 69 030 034 0043 a 092 195 a 469-714 130 85 010 035 0013 a 08)) 160 a 470-835 125 79 068 060 0052 a 071 260 a 00311 Hf 40-76 122 76 041 043 0044 a 082 042 a 0024 Zr 469-344 130 74 40 056 011 a 077 17 a 0019 Zr bull21543 124 73 004 008 0050 0019 a 0 7 002
Not analyzed bur no intentional addition made of this dement
Not analyzed but nominal concentration indicated
sample was a small tensile specimen 56 in in diameter X 1 in long having a reduced section in in diameter X I in long All specimens were annealed I hr at I I77degC in argon prior to exposure to tefliirium The results of crack measurements and data resulting from the tensile tests at 25degC that were used to open the embrittled grain boundaries are shown in Table 619
Experiment 7S-I was run by Brynestad and involved a sample of standard Hastelloy N that was immersed in LiCl saturated with C r T e for 146 hr at 750degC The specimen formed a heavy reaction layer (Table 6 7 ) but lost weight (Table 619) Figure 656 shows that the reaction was rather extensive with some obvioia grain
boundary penetration which resulted in extensive crack formation in the deformed section The extent of reacshytion in this experiment was higher than anticipated for an MSBR and therefore it is not believed that the experimental conditions employed constitute a good screening method
Experiment 75-2 was run by Kelmers and Valentine and the detailed results were described previously2 All samples lost weight in this experiment (Table 619) Although the samples had more reaction product en
21 A D Kelmer ind D Y ValentineWW Program Smi-anmi Progr Rep hth 28 1975 ORNL-5047 pp40 41
Tabic 619 Inlf(granular vracfc formation anrt loniU propcrD of raquomnllaquoraquo oPlaquoraquovd In ulltMlum and ilralnad lo faHurv al 25 V
ffimmti H M I MMttof
CilaquockiMui k |0gt
C m k t f w C i K k t c m
D t p In ) SlWMbi 4fvulMgtn
1raquogt
CMflOIIWt W I U M I
I M I
W f laquo k l bull lung lmlaquol
VMM t u t u
ltbullbull rail
U I W M I f M M HltMH
t l O 1 ptl)
f l M I I M f H l t U
lt I 0 p i l l
U m f w m f lMUt lWH 4 I 0 ^ I raquo
P l M I W f HIM
K n l i w i i M M M M
11 MMraquofclaquo
H M I MMttof CilaquockiMui k |0gt
C m k t f w C i K k t c m A M I i f M W I R H U H
SlWMbi 4fvulMgtn
1raquogt
CMflOIIWt W I U M I
I M I
W f laquo k l bull lung lmlaquol
VMM t u t u
ltbullbull rail
U I W M I f M M HltMH
t l O 1 ptl)
f l M I I M f H l t U
lt I 0 p i l l
U m f w m f lMUt lWH 4 I 0 ^ I raquo
P l M I W f HIM
K n l i w i i M M M M
11
5 1 40505 ) | lgt 111 101 lt 1 7 1 4 ) 1 I T 4 1 1 1 4 ) M i l gt I 4 HI raquoJ-1 4 0 5 0 5 5 ) 0 1 1 4 t gt 7 5 7 1 1 1 4 5 1 0 SI 7 1 ) 4 7 I I 71 4 0 4 4 1 1 43 1
470-1)5 17 A t 1 7 7 0 I S 4 4 1 1 1 7 7 1410 l ) t laquo 4 1 5 44 0 ) S ) 4 7 ) 5 0 ) 100 I I I gt)) raquo7 0 1 4 I I sraquolaquo 1 5 ) 1 1 1 ) 0 ) l lt 4 0 4 410
iao t ) 15 1 4 ) 0 1 D l A l 47 5 4 5 1 1 4 ) U S I M l ) t 1ST 7 5 1 40515 140 laquo5 17 1 4 1 1 0 17 117 4 7 uto 1 0 0 4 0 1 414 4 1 4
474lt5)4 110 17 145 1 7 4 5 1 4 145 S t 114 0 1 0 0 411 441 S I T 4 7 4 5 ) 5 1 ) 0 bull I 1 0 ) M 4 5 4 1 1)1 4 S 4 not laquo 7 4 7 4 lot S 4 )
7S-laquo 40505 4 1 0 5 7 0 11114 l raquo ) S l 1 1 1 1 1 1 ) 5 11 ) 15 1 bull raquo I 7 7 1 1 ) l 44 1 44 0 10) 7 I N M ) H I 1 1 1 gt I 0 ) ) i ) 1 4 4 1 4 4 1 0 7 5 5 405115 170 14 4 1 5 raquo 0 I S S 1 bull 0 1 5 0 111 1 1 1 7 ) gtS ) 7 1 1 1 1
4 7 0 laquo J J 10 71 ))) 14 7 1 0 1 I t S I 5 1 1 I M 1 I M 7 17 0 ) 7 1 1 4 7 - 40505 115 15 I ) 1 1 4 1 ) 1 4 4 0 bull 001 S i t 1 1 1 ) 1 1 7 1 4 0 4 4 1 0 ))raquo 7 J 7 40505 510 )ogt 4011 1 0 1 4 1SS k i t 1 1 4 ins ) I 7 ) 4 ))gt 7 ) 1 40505 ) 0 141 5 5 bull lll 1 1 7 ) )raquo) Sl l 1 1 ) 1 1 1 7 4 4 0 0 414 5 1 7Jraquo 40505 H O 141 4 1 7 5 ) 151 I I I 7 5 1 1 1 7 ) 1110 M S 41 1 gtraquo4
4 7 1 0 1 4 l i 7 ) ) 7 4 )laquo I D 4 4 bull 1 4 4 7 1 1 ) 4 105 0 laquo raquo l 5 4 1 4 4 4 7 4 5 ) 4 ) 0 14 1 1 5 4 5 5 107 ) 1 7 I t l i t 1114 4 gt gt 45 S 411 15 140 I S 10 1 J M raquo l J7 0 5 1 5 1114 I D ) 4 t ) 4 1 ) 4 7 t HI 15 10 1 7 1 U I laquo I I bull ) 0 )raquo 1 0 1 7 4 U l gt 7 I S T )
M S 100 )raquo )raquo 4 l 1 1 1 1 4 bull 0 7 1 1 7 I I 1077 M l 41 I 4 raquo ) H t i l l ) 1 0 7 441 100 ) S bull 0 4 551 I l l 1117 41 1 44 7 4 7 1 M l 4 l I S ) l i 0 ) M l 1 1 ) 4 1075 4 1 5 4 5 511) J41 170 0 raquo I I I ) 7 ) l i i bull 1 S l l 1)1 1 l l t l 4CI 4 ) 1 4 ) 50 450 177 11 o 1 7 7 ) i i bull 0 1 too 1)00 1 1 1 17 4 4UI 4 ) 4 50) 450 l lt 1 4 1 1 raquo l i bull 1 1 I t 1 111) 1100 471 445 4 0 raquo 7 J i l l 111 1 1 0 4 1 0 1 1 u bull 1 1 t l 1 l i t ) 1 1 7 1 ) S gt ) T 4 4 1 5 15 15 10 10 1 1 7 ) i s 1 5 5 ) 5 1 1 ) 1 I M S 4 gt ) 4 4 4 4 4 1 )7 IS )) 14 1 ) I S I S i 0 5 1 4 l i l t I M S 4 ) 5 4 4 ) 4 4 505 H O 141 I t ) 1 7 1) 1 4 bullUS 5 ) 1 D t S 1 1 7 ) 4 4 1 4 1 4 7 7 M l 1)0 D O 1 7 ) 107 bull 4 1 1 bull 0 4 7 1 ) l l ) t 1104 4 1 7 4 raquo 4 7 11 110 17 1 7 1 1 1 7 ) 7 7 4 M I 1171 m i 4 1 4 4 S I M S ] 10 11 1 gt 1 4 0 4 4 5 IS 1 5 4 7 117) 110 1 4laquoT SOT 4 1 1
) 440 17) 117 1 7 S ) 1 I S l l l ) ) 4 111 7 gt J ) ) l o 41S 4 4 4 1 ) ) 0 1 ) 0 I I I 4 ) ) 7 4 1 bull 0 1 I I 1)1T 117) 4 ) 7 4 1 445 4 7 | 4 1 ) )) 114 5 0 4 1 1 4 5 bull 0 0 1 4 1 1117 l i t ) 8 ) 7 Hi 4 ) 4 4 7 0 O J ) )bullbull 1 1 4 7 SO 1 0 0 ) 5 5 IJ75 1)04 414 477 4 5 4 7 0 7 t )) 1 ) 1 ) 1 5 7 1 14 S 7 ) 0 ) 4S l i t 7 1 0 7 ) 5 0 4 S I 7 40 1 4 5 4 4 )raquo 141 l 171 V I 1 ) bull 0 07 5 1 7 1 ) 1 1 1 1 0 ) I 0 ) raquo 7 414 4 1 1 5 4 ) bull5 )) I I 1 4 4 4 1 17 11 45 4 not M I MT 5 7 )))
75 10 40505 M O I ) ) 177 4 1 ) 7 1 1 bull 0 0 4 5 ) 1 1 ) 1 4 1 1 ) 0 4 0 4 gt I 4 4 0 415 ) 0 0 I I I 17 1 54 1 I I 1 4 1 bullOS S l l l i t a 1 1 7 4 7 411 411 415 140 5 1 1 7 5 1 0 1 ) 4 ) laquo 0 0 l t i l l i t ) I I I ) 4 1 ) 410 4 7 411 M O 1)5 M4 raquo0 l 1 0 1 1 4 0 0 ) sso 1 1 7 111) 4 ) 7 4 5 4 4 1 4 414 4 ) 0 1 1 7 501 14 1 0 0 ) bull 7 4 l ) raquo ) 1 ) 1 7 44 1 411 gtbull) 11 101 1 1 17 1 0 54 0 74 bull0 1 1 ) 4 1111 1 1 ) 0 4 7 1 SI 1 1 1 7 15 M 10 I I I 1 5 1 ) l bull 0 1 5 ) 4 m i 1117 4 1 4 4 4 4 47 ) 541 M 1 ) 1 1 M l 71 15 bull 5 4 1 i n 107 1 44 1 4 7 4 54T M 5 15 5 raquoraquo 141 gt) i n bull 0 0 1 5 1 1 1 4 1074 4 4 ) 4T4 4S4 415 M 11 105 117 5) I S bullooi 5 ) 0 i n I IS S H 4 4 44X1 411 1 ) 141 ) 5 laquo 1 5 1 bull 14 4 1 1 1 1 ) 4 bull T I S I M l 5 ) 4
4 1 1 5 4 ) 17 7 10 1 ) 7 I I gtraquo bull 1 4 7 ) I D 1014 S I ) 1ST 5 ) 7
4laquou i MM tun bull 15V al bull tiiaM M M ul 0044 Mgt 1uUl laquomlil raquof yfmmtri 1 1 l o t 1 )
112
raquo gt laquo laquo bull
(b)
pornnaof
0-010 in 0 25
U t a M H I i th) tdft oi ureaed poriioa of 1
llaquowraquoCr Tca i7Mrci IflOX
HkrltlaquoiE ytoT
one end than the other the extent of lt icjaunably uniform Typical plsotonucrognphs of the (oar materiab are shown in Fig- 637 Aloys 40506S (standard) and 472-503 (216 Ti) formed extensive cracks but aloys 470435 (071 Ti 260 Nb) and 190 ( I J49 Nb) were considerably more resistant to cracking
in experiment 75-3 three samples were packed in CrTe grannies for 250 hr at 650degC The samples formed heavy nonadherent reaction products and lost weight (Table 619) All three materials formed extenshysive cracks (Table 619 Pig 638) with the depth of cracking being slightly less in the two modified alloys (474-534 and 474-535) than in standard Hnstdfoy N (heat 5065) However the extent of reaction is too high under these conditions for the results to be meaningful
bi experiment 75-4 duplicate samples of standard HastePoy N (405065) were packed in granules of CrTe4 and heated 200 hr at 700degC The samples formed nonadherent reaction firm and lost weight tarshying the test (Table 619) The reaction layer and the
the reaction rate was un-of the exposure cnadnioni as a
bull Fig 639 reasonably high for a
k experiment 75-5 Iryneslad and Keaer two specimens to MSW fad carrier salt (c uranium) that was saturated with CrjTcj The exshyposure was for 504 hr at 700C These samples formed reaction layers but lost weight (Table 619) As shown in Fnj 660 both uatcinls formed reaction layers but in heat 470-835 (071 Ti 260 Nb) there to be less penetration of the rcactants aVng the | boundaries The standard Hastdoy N had regions where layers of grams dropped not during the exposure The number and depth of cracks in the sliessed portion of the samples were less for heal 470435 than for stanshydard Hastcloy N but both materials formed extensive intergranutar cracks
Since the samples packed in the various telurides reacted extensively several experiments were run Hi which the samples and the teluride were separated in
113
(a)
(b)
(c)
- r - raquo
(d)
0 25 MI FfcS7 SywiwuM fcmdasht tfmmmm IS-l wfcMl wmdash laquo y mdash lt iraquoraquofciraquo raquo w laquo r f p w raquo o r irtNilmi far I W H m 7 W C n i
NralltOAraquo5tfrlfcril4-Slttilt I TiM Ilwtf 47MJ5 llraquo7l-lt Ti lA SbKultkat MRi lA f r Hbt AlaquopoMwl lOOx
114
(c )
(laquo )
(f) raquo bull O O W f
0 2 S laquo raquo
fplusmn S Ipniawn tnm rxpummM 75-3 Packed m CrTe granules for 250 hr al 650 C and deformed lo fracture ai 25 f flaquoraquo Heal 405065 Msireaed thy hear 405065 Urevwd tei heat 474-534 (2091 Ti 00131 Lagt imlaquorclaquoed (ltraquo heal 474-534 tlrcuedfrgt hear 474-535 (2131 TiOOH La 0031 Claquolunlaquoreslaquodlt1 heal 474-SJS laquorevd Atpnnshed lOOx
115
3ampF
bull 025am bull
the reaction capsule In experiment 75-6 standard Hasteuoy N was reacted with the vapor above CrTe 4 at 7000 for 1000 hr The spedmen pined a amount of weight (Table 619) did not form a reaction layer (Fig 6J6I ) but did form extensile inter-granular cracks (Fig 6 J 6 I Table 619) Experiment 75-7 was run in the same way but Cr 2Te was used The sample tost weight formed a surface reaction prodshyuct and formed mtergranutar cracks when strained (Table 619 Hg 662) In experiment 75-8 the source of tellurium was two nickel leRuriJes fc and 7 i The specimen lost weight did not forn a TJIMC surface reaction producl and did form rnieigranubr cracks (Table 619 Fig 6J63)L From these experiments it was concluded that the tellurium activity produced by Ct Te 4 was likely that best suited for screening studies
ExpeiHMnt 75-9 included 25 aloys which were exposed to tellurium vapor at 7000 for 250 hr The weight changes covered a range of +84 to 74 mg with no obvious correlation between weight change and crack depth or number (Table 619) These specimens were sealed in four different capsules for exposure to tellurium and there were differences in the extent of discoloration of the samples These differences are likely associated with slight differences in the extent of reaction due to variation of the temperature of the tellurium metal in the various capsules Thus it is quesshytionable raquo to how far one should carry the analysis of the data from this experiment
Owe further problem coacernmg data analysis which applies equaly w d to afl data sets is the baas that should be used for comparison The number of cracks ami their average depth are two very important paramshyeters However it is possible that a Tprrimrn cm have a large number of shaaow cracks ( e ^ beat 63 Table 619) or a few rather deep cracks (eg heat 62 Table 619) The formation of intergranuiar craci of any depth is important because this may indicate a tenshydency for embrittlement The depth of the cracks ts important because this is a measure of the rale of peneshytration of tefurium along the grain boundaries Howshyever for a relatively short test time (test 75-9 (2S0 hr)) the formation of numerous shalow cracks may be indicative of a near-surface reaction which wil not lead to rapid penetration with time Obviously longer-term tests are needed to determine the rate of penetration of tellurium into the metal
On the basis of number of cracks formed the alloys in experiment 75-9 which formed lew than 40 cracks per centimeter were 345470-835421543 237469-714 470-786 62 295 and 348 The alloys forming cracks with an average depth of lt 127 u were 63 469-714 295 348 469-344 421543 and 470-835 Several of the alloys appear good on the basis of both criteria These alloys all cont in niobium and several contain niobium and titanium Another parameter used for comparison was the product of the number of cracks and the average crack depth The alloys from expert-
l i t
( bull )
laquo
ltlaquov
(c)
lt)
I 0 2 9 raquo raquo gt Figt iuM Senates from uteiiaini 75-5 Sanpln exposed to feci all sraraKd laquo-iih Cr Tc for 504 hr ai 700C and strained
lo fraclarc al 25T ltraquo Standard HasteHor N bullntlrencd shoaMer (Agt standard HasteHoy N stressed p(c length sfoning region where grains were urn dnrine tall cipotnre (lt-gt heal 4704135 10717 Ti 260 Nb) oatlrroed thoakitr ltltgt heal 47f 4J5 stressed portion Aspotahcd I00X
117
(a)
(b)
l f l laquo Q l n - | I 0 2 9 M I
Flaquofcl TtiMwi lUmBij X ( h w O W I I w lono br mi earned to fjUarc ut F4pr of MM icwd pvnna iraquo lt
1154k ampMOftrtrfKMe4 lo the of tiinaei porno As pufcihfi
CrTlaquo j i7laquorCfof IflOx
ment 75-9 are ranked on this basis (Table 6J0gt Stan-dard Hasidoy N raquo significantly different from al other heats on this basis There are latfe variations among the other heats but it is difficult to pick out general trends on the basis of niobium and titanium concent rations
Several typical photomicrographs of samples from experiment 75-9 are shown in Fig 664 No reaction films were visible on any of these specimens The picshytures show dearly the wide range of cracking experishyenced by the various heats
The mechanical property data show small but signifishycant variations in the yield and ultimate tensile stresses of the various heals (Table 619) The higher stresses are grnerolly associated with the alloys containing the higher amounts of niobium and titanium However the
high fracture strain and reduction in area for a l h-ais indicate that only very small (if any) amounts of gamma prime formed during the 250 hr at 700degC
In experiment 75-10 steps were taken to ensure that the specimens were at a uniform 700degC and that the tdurium was at 300degC The weight changes were very erratic and show no correlation with the number of cracks or the depth of crack formation (Table 619) A sample of heat 425 was included in each of the two capsules used in tins experiment to obtain some idea of reproducibility The reprodudbflity was reasonably good Samples o alloys 405065 298 295 348 and 345 were included in experiments 7 5 4 and 75-10 Heats 405065 298 and 345 in experiment 75-9 cracked more severely than in experiment 75-10 Alloy
l i t
V - t
(b)
I AW hr art in
021 uigtiiiwil75-7 iioafAtlaquo4acor A
Cr f e j i ltKraquo lt t t HMta
laquo bull - - Craquofc
ltW SS^j-^n-raquobull
WMMMCS at ItXfC foe IWO hr aa laquo u m lt lo f IflOx
0 2 9 laquoMi itmtm 7W San phi r^puraquorf to Ike
to) Mat of mmiiwmtd porta raquogt claquogt laquo tf bull gt mcfcd
puftimi A ^riuhfd
IN
ITS
note bull bull laquo tat tract tdncti0c4 I cy
roat i
H m i oaccatraaoa t 0
( - -
I cy
roat i
H m Ti Nb (Mm
5laquon 4ltI5laquoraquo5 371 3lraquo 0 3 5 027 Si 3195 474-534 2 4 9 01013 U 27 JO 471-114 175 247 303 049 OM 2400 3ttS OM 13 2249 29S 20 217 3 2-5 2 1 29 024 0 3 7 1993 347 raquoM 0 4 7 Si 1924 4S14M 092 195 I9 IO 474-5J5 213 0 4 4 L raquo raquo pound r IBSI M U M P27 15 C i 1453 I I I 050 l-SS 1304 344 04laquo 049 1292 49-344 077 17 9 9 345 045 ft22Si 4 M 237 1J03 409 49-714 0S0 tJampO 352 2 1 9 raquolaquo 4 7 M 3 5 071 IM 290 421543 07 179 4707S 082 0 4 2 101 295 0 M 3raquo 34S 062 047 Si
Set TjNe 1H lw drbiM cheiwcJ jiulvcs
348 was less severely cracked in experiment 75-10 and Nat 295 reacted similariy in both tests Such differshyences emphasize the importance of duplicating test results before making important conclusions
The alloys in experiment 75-10 that formed lt32 crackscm were 413 34 295 4 1 1 421543 and 345 Those with average crack depths s 109 p were 421543 295413 345 and 298 Again this ranking is of quesshytionable value because alloy 298 had the shallowest cracks of the 12 specimens but formed a large number of cracks In an effort to combine the factors of number and depth of cracks the two factors were multiplied and the alloys ranked as shown in Table 621 There is a very large step between alloys 425 and 298 and the better alloys appear to be ones containing from 045 to 20 Nb with titanium additions of 1 ^ or less
The tensile data show small variations but do not show evidence of embriitiemeni due to gamma prime formation during 250 hr at 700degC (Table 619) In specshyimens from experiment 75-10 the wide range of trackshying behavior is apparent (Figs 665 and 666)
These tests have shown that several methods are availshyable for exposing metal specimens to tellurium The metal tefluride Cr Te 4 has an activity most consistent with our estimates of tellurium activity in an MSBR Specimens can be exposed to salt containing CrjTe 4 or exposed to vapor above the compound Tellurium metal at about 300degC has a vapor pressure of about I X 10 4
torr and appears IO provide a tellurium activity comshyparable to that expected in an actual MSBR The specishymens exposed thus far show that niobium is effective in reducing the extent of iniergranuiar embrittlemenl of Hastelloy N
615 EXAMINATION OF TeCen-l
B McNabb H E McCoy
The TeGen series of capsules was designed for studyshying the effects of tellurium and other fission products on metals The fuel capsule is a Vi-in-OD X 0035-in-wall X 4-in-long tube segment of the metal under
120
( c )
I OOIOf - _ I I J 0 2 9 M I
Fagtfcj64- CumdashjMiiun of imdashapamdashtm cmfcif bull l l i jNluj H lyye aBoyraquolaquoaoraquod wgt partial aitmdash11 erf tdNrimdash of 10 vm fat 250 br at 7WTC aad iliaan lo fraroarc at 2SC ltlaquoraquo Standard Hasfcttoy N that 4O5065i (142 crjckwrn a depth 416 raquoraquo IM modified Hastcfloy N containinc 08S^ Nb (aNoy 295) (10 crackson a depth 101 raquogt laquorgt modified Hastdloy N conlaaunK 082^ Ti 0427 Nb (alloy 470-786) (13 crackscm a depth 86 it 00x
Table 6 J I Rmdashfciwiof materials from expuimoH 75-10
Product of number of cracks and average epth
rnns) Alloy
number Concentration CJI
cracks 1 x rntci cm
epth
rnns) Alloy
number Ti Nb Other cracks 1 x rntci cm
4512 424 18 134 3245 421 219 104 3198 425 198 048 2328 405165 2157 425 198 048
713 298 20 336 413 10 113 209 348 062 047 Si 133 411 115 106 295 085 76 421543 07 45 345 045 022 Si
See Table 618 r detailed chemical aiulyicv
121
ltd)
( f )
I 0 2 5 M B I
Ff 65 Miami tpwmriw from expuwww 75-10 SpccmKru were cxrvwrd f-r 5n hr ji nn lt- ilt ihr apltlaquor iNiw irlluintm meiil JI nit C bullgt All- 424 iM jllgtgt i i rIjHn 45 II allot 4050 in allm 45 (gt alloy ^gtraquo A pohthrd Wfr
122
-1MS7t
(f) laquo0fllQH -
025 mm Fig 666 Stimti specimen from experiment 75-10expoatd tot 250 hraf 700Cfo fherapor above idmriwn meM it 300degC
(j) Alloy 413 (ft) alloy 348 ic)alloy 411 Irfraquo alloy 295 (ltbull) alloy 421543 if) all 345 A polithed IOOx
123
study The capsule is partially tilled with the MSRE-type fuel salt and irradiated in the ORR to produce fission products
The first experiment of this series involved fuel pins made of Inconei 601 standard Hastelloy N and type 304 stainless steel and the irradiation time was such that the amount of tellurium produced per unit area of metal in contact with salt was equal to that at the end of operation of the MSRE Some of the details of the postirradiation examination were described preshyviously2 2 A typical fuel pin is shown schematically in Fig 667 The segments marked A w re subjected to tensile tests using the fixture shown a Fig 668 The mechanical property data obtained roai the rings and the results of limited irtetallograpic examination were reported previously2 z More detailed mctallographic studies have been completed during this report period The segments marked B were used for chemical studies The salt from each segment was analyzed and the fission product distributions on the tube surface and a short distance into the tube were determined from two successive leach solutions The first leach used a verbodt solution (sodium vtrsenate boric acid and sodium citrate) which should have dissolved only residshyual salt from the metal surface The second solution was aqua regia and the time was sufficient to remove about
11 B McNlaquohb and II I McCoy IfSR Pnrmm Sununnu Pnifr Rip Feh gt tv~ ORM-5ltMpp 12 6
I mil ot the tube Both solutions were subjected to various chemical procedures to analyze for various nuclides and elements These results are partially anashylyzed and the results for tellurium will be discussed The tube segments marked ~C were retained for posshysible future studies
61 SI Metafognpaic Observations
Photomicrographs ot the three materials in the un-deformed condition are shown in Fig 669 Numerous voids were present near the surface of the Incopel 601 specimen to a depth of about 02 mil Voids were likely caused by the removal ot chromium from the alloy via reaction with U F 4 in the salt The Hasldloy S vrction shows no evidence oi chemical reaction with the salt The type 304 stainless steel shows some grain boundary attack to a depth of about 0_5 mil This was likely caused by selective removal of chromium along the grain boundaries The features in the type 304 stainless steel appear much like shallow cracVs and may have influenced the number of cracks that were observed in stressed samples of this material
Composite photomicrographs of the Inconei 601 rings after straining to failure are shown in Fig 670 Rings 2 and 4 from near the salt-vapor interface exhibit some evidence igt( attack but the other samples are almost entirely free of indications of chemical reaction
Photomicrographs of the deformed rings from the Hastelloy N capsule are shown in Fig 671 The count
olaquoM-oac n-ot
TTPt DESCRIPTION M O USE
bull VW bullbull IMG FOR HCCMAWCAL PROPERTIES
B fOU L E A C N (2 STEP
C StCTiQM TO K RETAINED
mdash EH0CAR
mdash A - i
4 -2 A-3 AN0 SALT LEVEL
z~ -laquo A-5
- S A-4 A - mdash C
mdash A - a A - raquo
mdash A- IO
mdash C
mdash A - M mdash A-12
mdash C
mdash A-13 mdash A-14 mdash A-15 mdash 8 mdash A - W mdash EMC CAP
f 667 Schematic docram of individMl feci pm jhowing the locaftoMof tat specimen
124
metaliographic sample indoles the fracture and an adjacent segment Since the fracture occurred at difshyferent locations the metallographic specimen contains varying amounts of inhomagcneously deformed mateshyrial For example Fig 67 I f includes a very small segshyment of homogenously deformed material whereas Fig 6 71 includes a relatively long segment As shown by the photomicrographs in Fig 671 and the data in Table 612 specimens from the vapor region (2-A-I) the salt-vapor interface (2-A-2) and rite bottom of the salt (2-A-l6) cracked most severely Three samples from other locations formed shallower cracks It is not known whether these differences are significant
Typical photomicrographs of deformed rings from the type 304 stainless steel capsule are shown in Fig 672 These specimens located on the inside surface had shalshylow cracks with an average depth of about 04 mil (Table 622) These cracks were rather uniformly distrishybuted in the samples from all four locations As noted in Fig 669 the unstressed specimen also contained cracklike features having a maximum depth of about 05 mil Hence the cracks in the stressed specimens may simply be the result of furti opening of features that are likely related to corrosion
6152 ClKiMcal Analyses for TeBormm
The lube segments designated B-l B-2 and B-3 in Fig 667 were subjected to several types of chemical analyses but only the results for tellurium have been analyzed in sufficient detail to report at this time The results for the three pins are shown in Tabic 623 The
Ffc668
0 Fixlare for ft leatinj rinji
of crack frequency shown in Table 622 was made in an effort to detect significant differences in cracking among the various specimens These counts are subject to numerous problems the main one being the inhomo-geneous distribution of strain within the sample In deforming the ring specimens in ihe fixture shown in Fig 668 the small portions of the ring located between the two parts of the fixture likely deformed very unishyformly but this length is very short relative to the total length The part of the ring that contacted the fixture likely deformed in some areas but was restrained in other areas by surface friction from the fixture The
Taate 6 J2 Smmmmy of crack frequency aad depth inToflMtiM for riant from TcGea-1
facts alaquo W M M t ID ratae at 25deg C
from TlaquoGCM fad Specimen nu iber
Crack frequency
(crack sin)
Crack depth (mils)
Average Maximum
2-A-l 480 080 20 2-A-2 450 II 22 2-A-4 410 060 12 2-A-5 480 058 12 2-A-8 MO 046 10 2-A-l 6 380 14 25
Type 304 (taMeu tted
1-A-2 160 04 12 3-A-4 310 042 10 3-A-8 260 036 10 3-A-I6 202 037 10
125
(a)
-J
(b)
(c) 20 40
- L - 1 _ 0001
60 MICRONS lt00 mdash SOOX -
laquo20 40
INCHES COOS
Fjj 669 Undeformed rings (ample No 9) from each TeGen fad pin near the middle of the fael aalL (a) Inconel 601 (ft) HuMelloy N(r) type 104 ttainlets jteel A polished 500x
600 inn
Ffc 670 Sample from Incond 601 fad put from TeGcit-l Kir failure al 25deg0 Portion of specimen exposed to fuel salt is on the I location A A (laquo) location A-5fr) location A-8 () location A-16
BLANK PAGE
Sch figure
j J u i u m l i i -Mi iWWLltLiWHt
126
a ten from (he location shown in Figr 667 and deformed to tide of cacti figure it Location A - l tftgt location A-2 ( r )
J
127
I Fig 671 Samples from Hwribr N fuel pin from TcGcn-l I bMurr M 25 ( Portim of specimen epltlaquoeraquol ilt fuel sill ii on l l location A-4laquo) lotjlion A-5 ltr) loolion A- i ft loci lion A-16
- l i bull gt i i glaquo i^_ a ^ bdquo ^ ^
ten from (he Uttattnas lthlaquown in I ijt A fc7 jlaquod deformed lltgt tide of ejch figure fat Location -1h) location A-2raquorgt
^
I
I t - -
BLANK PAGE amp bull
^bull
raquo-raquoMlaquoraquoWr
F)B 472 Sanata tmm lyat 301 itiialf steel fad pin ham Te atfunwed lo (xtmn at 25 C Poriwtt of specimen exposed lo fuel I locatio 4A to location AAIlt) location I6A
~^raquo-raquo i i T -- T-II bullraquoMraquoraquoMr5w mi j immmtmt^m
mm - bull - - bull bull bull - bull -
BLANK PAGE
mdash t - bull bull-bullbull -r^gatMtJliHwJraquoiWrraquovraquotj^WVu^-4-tgt- ~J(W~
fiMAmimraquom0mfMraquo-mdash- --- bullmdashmdash~~^--raquo bull
128
600 iim
M type 904 minim Heel fad pin from TlaquoClaquoM-I Rings taken from the locations shown in Fig 667 and C Portion of specimen exposed to fuel salt is on the lower side of each figure ltn Location 2A Ih) (lt) location I6A
2 ^ - m TMinfc
BLANK PAGE
128
600 pm
Ac locations shown in Fraquo 667 and bullf each fifiire It) Location 1A (ft) 3 L +ot nMtmgwmm
129
rlaquoJ3 raquo T e i bull Tea
nmHtrntMiaoam location
Type Concentration of bull T e C o ~ e ~ r t - o f bull bull T e nmHtrntMiaoam location
Type
bullpm total at JpnWg gcnr at i f f bull p a i o t a l o t a p a V l an or i a f
No 1 - IncondtOI 11 111
A B
S 2 J X 1 0 4tS X 10
4 2J7X 10
poundraquoSx 10 237 x 10
4 444 X 10
IB2 IB2 IB2
A B C
lt2J x 10 159 x 19 7laquoS X 10
4 r7SX 10 114 X 10
lt2J7 x 10 bull00 X 10 744 X 10
4 113 x 10- 45 x 10
IB3 IB3 IB3
A B C
pound53 x 10 27 X 10 247 x 10
4 345 X Iff 331 X 1 0
lt l 7x 10 34 X 10 143 X 10
4 57 X 10 99 x 10
No 2 - HasteHoy N 2raquo1 211
A B
lt M ( 10 749 X 10
4 3-Mx 10bull
lt I 4 4 X 10 497 X 10
4 094 X 10
2B2 2B2 2B2
A B C
raquoj x 10 29S X 10 7t X 10
4 Ml x 10 bull 5 i x 10
lt5 4x 10 202 X 10 594 X 10
4 3-7 X 10 24 x 10
2B3 13 2B3
A B C
lt54 X 10 laquol9x 10 34SX 10
4 422 x 10 bull 249 X 10 bull
lt 5 4 x 10 bull 05 X 10 393 X 10
4 U l x 10 141 x 10-
No 3 type 30 stainless start
3BI 3BI
A B
552 X 10 131 X 10
304 X 10 072 x 10bull
959 x 10 143 X 10
IS0X 10 3-44 x 10
3B2 3B2 3B2
A B C
954 X 10 25copy x 10 900 x 10
bull29 X 10
131 x 10
30 x 10 340 x 10
1042 x 10
bull J l x W iat x io 4laquoX 10
3B3 3B3 3B3
A B C
I M x 10 127 X 10 S3S x 10
116 x Icopy 044 x 10 74 X 10 bull
542 X 10 315 x 10 323 x 10
3-3 X 10 19 X 10bull 197 X 10
A denotes 100 a n aarntwn obuiotd by leaching the metal nanjlr m mbocit (soJimdash Tersenate boric an mdash I iiiinmdash cttnlel B i 100 cm sowlion obtained by l u i l raquo n the metal amftt m raquoraquobullraquo reeja lo remore aboat I M i of nartaLC denotes 100 cm sotation obtained by distorting aboal I g of salt in Mtric icid ( I JO saturated with bone acid Counts for iniiiidojl Radioes gram in dionfegralions pei Minnie (dpntt total for chemistry types A and Band dpM per graa of salt for type C daroMBry saMpfc These cooam ace laboratory w n t u i and abject to sctta corrections omkh lane not been none cThese concentrations are espitjatd as grams of the particnlar nncMr per CM of Metal sartace for cheaaatry ample types A an B ant ar exams of nailidc per gram of alt for chemistry siMpli type C The nines hare been court nd back to the conrfcjsiBn of die H amnion Concentration flwinglit safTiciently low to be ignore
sample numbers ending with I (ie I B l 2B1 and 3BI ) designate the material that came from the fuel pin wall exposed to the gas space above the salt The ample numbers ending with 2 designate material that came from the fuel pin exposed to the fuel salt just below the sail-gas interface and the sample numbers ending with 3 designate material that came from the portion of the fuel pin exposed to fuel salt near the bottom of the capsule Solutions were prepared for analysis by leachshying metal samples of each tube in verbocit to remove residual salt (type A solution in Table 623) leaching the rings in aqua regia (type B solution in Table 623) and dissolving about I g of salt removed from the metal rings in nitric acid (type C solution in Table 623) These solutions were counted to determine the amounts of J 7 T c and T e present The direct results of
these analyses are presented in Table 623 but cannot be interpreted directly because a number of corrections have not been made The data have been corrected as well as possible o reflect the concentration of each nuclide at the end of irradiation The concentrations for the leaches from the metal specimens are expressed as grams per square centinpoundtcr of tube wall exposed to the fuel salt and the concentrations for the salt samples are expressed as grams per gram of salt
The ORIGEN code was used by Kerr and Allen to predict the concentrations of tellurium isotopes that should have been present These calculations have been used extensively in the subsequent analysis of the data Table 624 compares the quantities of 7 raquo T e and l l laquo m T e f o o n ( j m | h e ( n r e e f ^ i p j p W j ( n thoje p r e
dieted to be present by the ORIGEN calculations For
130
each fud pin the one sample taken of the tube in the gas space was assumed to be typical of that region and the two samples from the salt-cowered parts were avershyaged to obtain a typical value for the salt-covered region As shown in Table 6 2 4 generally about 20 of the T T e and 1 T e was found The percent of tellurium found in the Incond 601 capsule was apprecishyably higher due to the higher amount found on the salt-covered metal surfaces
There are several possible ex|)lanations why the conshycentrations of I 7 T e and 2 T e found are only about 20 of those produced One possibility is that the amounts calculated arc too high This appears not to be the case but the calculations wiQ be checked further The most likely explanation is that the add leach was not sufficient to remove all of the tellurium from the wall The tube segments were suspended in the acid with the made and outside surfaces of the tube wall exposed as well as the cut surfacr on each side of the ampin tube segment Based on the weight changes obshyserved and the assumption of uniform metal removal the thickness of metal removed appears to be about 08 mil Since the cracks extended deeper than 08 mil in the HasteDoy N the tellurium likely penetrated deeper than did the leaching solution However the cracks in the other two materials were very shallow and the
08-roii dissolution should have recovered a higher fracshytion of the teflurium if one can equate the depth of cracking to the depth of tellurium penetration The results in Table 6 2 4 show no evidence of a systematic variation in the percent recovered from the three tubes Several possible explanations for the apparent discrepshyancy in the quantities of teflurium generated and that actually found are being investigated but none appears reasonable at this time
The concentrations of 2 7 T e and 2Te found in the salt can be used to predict upper limits for the solubility of tellurium in fuel salt under these condishytions The I 7 Te nuclide concentration in the a l t ranges from 114 X 10 to 131 X 10 g pet gram of salt (Table 623) The ORIGEN calculations were used to estimate the ratio of l 2 T Te to total tellurium and this ratio was used to convert the above concentrations of T T e to total teflurium concentrations of 007 to 083 pom Smiariy the concentration of 2 T e ranged from 45 X 10 to 648 X 10~ g per gram of salt and these correspond to total teluriurn concentrashytions of OJOS to 113 ppm The low values in both cases were noted in the Inconel 601 pin and the higher values were observed in the type 304 stamhts steel pin The concentrations m the HasteSoy N pin were only slightly less than noted for the type 304 stainless steel pin The
TaMt624 A w o mdash l o f T CnhnsM bull n r i o t i kKSfuOtv ol fed pint tmm TcGea-I (a)
IncondoOl HastdloyN Type 304
mje bull T bull gtraquorT e T e mje bull T bull gtraquorT e T e bull T e bull T e
Salt 41 x 10 bull 13 x 10 - 10 x 10- 35 x 10 M X 10 74 x 10 Metal-vapor space 14 x 10 24 x 0 21 X 10 50 x 10 2Jgt X 10 i2 x ie- Metal-sll covet at 17 x 10 23 x I t r 78 x 1 0 25 x 1 3 44 X iW 39 x 10 T
Total fomd 19 X ltgt-bull 27 x IC II x 10-bull 3 5 x 10 laquo 2 x 10 23 X 10 Total formed 3 A 2 x 10 bull 134 x I 0 f 40 x 10 148 x 10 36 X 1 0 134 x 10 laquo ferccM found $2 20 2raquo 23 23 17
of frnl MM hum TlaquoGcn-l (10 aon)
Location Incoiwi bull 1 HastcftorN Type 304
is sled Location bull T e raquo T laquo T e bull T e
Type
bull T e raquo T laquo T e bull T e T e T
Mctal-vapor space Bl MetaMaii location B2 Metal-salt locaiion 83 Avenge if foul yield evenrr distributed
257 bull 75 345
112
446 113 576
413
3J6 152 422
123
94 376
IS 1 456
376 229 095
112
214 I M 103
413
131
higher chromium concentration of the Inconet 60 may have caiced the lower tellurium concentration in the fuel salt
The con-entrations of l l l m J e and t 2 9 m l e are expressed in Table 625 in terms of grams per unit surshyface area There appear to be significant variations within each capsule but there is no consistency beshytween the various pins The high value for ITe in the vapor space of the type 304 stainless steel pin is likely anomalous since the n T e t$ not i s high Thus ai this time we conclude that the tellurium is distributed uniformly over the entire surface area of the pin
616 SALT PREPARATION AND FUEL PIN FILLING FOR TeGea-2 AND -3
M R Bennett A D Kelmers
The purpose of this portion of the TeGen activity is to prepare purified MSRE-type fuel salt containing bulliiV and to then transfer a known quantity of this salt into fuel pins gtr subsequent irradiation in the ORR One batch of purified salt will be prepared and used in two filling operations to fill two sets of six fuel pins each identified as TeGen-2 and TeGen-3 Similar activishyties in 1972 to fill the fuel pins used in experiment TeGen-I have been previously described2 3 To MSRE-
type fuei carrier salt containing LiF-BeF-ZrF4
(647-301-52 moleltv)sufficient U O j and 2 U F 4
were added to produce a fmji composition of LiF-BeF -Z r F 4 - I 3 3 U F 4 - 2 U F 4 63J08-29J5-5 O7-1 0O-15O mole ) after hydefluorination to reduce the oxide content The uranium will be reduced by hydrogen or bv beryllium if necessary to a U3 content of 10 to 18 and a measured xlume of salt will be transferred into the fuel pins The design permits obtaining a preshydetermined volume in the pins by flushing through an excess salt volume and then blowing back the salt in the upper portion of the pins to leave a predetermined volshyume
The equipment in Building 4508 used previously for this work was reactivated and modified where approprishyate A safety summary and step-by-step operating proceshydure have been prepared and approved During the latshyter part of this i port period the salt components were charged to the salt purification vessel and a 364ir hydrofluorination at 600degC was completed Both filshytered and unfiltered samples were obtained after hydroshyfluorination in copper filter sticks After analytical results indicating satisfactory removal of oxide liave been received hydrogen reduction of about 1 of the UF 4 will be carried out
23 R L Sain J H Suffer H E McCoy and P N HjabcnrcKh MSR htrprnm Srmmcvni trofr Rep Aug il 1972 ORNL-4832 pp 90 9
7 Fuel Processing Materials Development
J R DiStefano H E McCoy
The processes that are being developed for isolation of protactinium and removal of fission products from molten-salt breeder reactors require materials that are corrosion restrtint to bismuth-lithium ind inoiiev fluoshyride solutions Past experience has indicated that alshythough their solubiities in bismuth are low iron-base alloys mass transfer rapidly in bismuth at 500 to 700 SC The most promising materials for salt processing are molybdenum Ta-10^ W and graphite Molybdenum has been tested in a wide range of bismuth-lithium solushytions for up to lOjOOO hr and has shown excellent comshypatibility Thermodynamic data and literature reports indicate that molybdenum will also be compatible with molten fluoride mixtures
Ta-10 W also has excellent compatibility with bismuth-lithium solutions but tests are required to measure its compatibuity with molten fluoride salts A thermal convection loop has been constructed of Ta-10 W and a test with LiFBeF2-ThF4-UFlaquo (72-16-117-03 mole ) wffl be started during the next reporting period
Graphite has shown excellent compatibility with both bismuth-lithium solutions and molten salts Although no cheruicai interaction between bismuth-lifcisas solushytions and graphite has been found the hqtsd-KjsuS solushytion tends to penetrate the optn porosity of graphite Recent tests have evaluated the extent of penetration as a function of structure of the graphite and the Uthium concentration of the bismuth-hthium solution Dynamic tests of graphite with bomuth-tithium have thus far been limited to quartz oop tests circulating K - 0 J 0 I wt ( 0 3 at ) Li During the report period a test was
completed in which graphite samples were exposed to Bi-24 w 1 (42 at vt) Li in a molybdenum thermal convection loop for 3000 hr at 600 to 700degC
71 STATIC CAPSULE TESTS OF CRAPHTTE WITH BISMUTH AND
MSMUTH4JTHIIJMSOIIJ110NS
J R DiStefano
Samples of graphite with varying densities and pore diameters were exposed to H-017 wt (48 at ) Li and K - 3 w t (48 at ) Li in capsule tests for 3000 hr at 650degC Two of the graphites (Table 71) were pitch impregnated t j increase their densities and reduce their pore sizes1 The relatively high densities of these graphshyites indicate that impregnation was effective but the pore size distribution in the samples shows that some of the larger pores were unfilled or only partially fdkd Specimens were graphite rods 6 mm (024 in) X 381 mm (15 in) long that were threaded into an ATJ graphite holder The specimens and holder fit into a graphite capsule which contained the bismuth-lithium solution (Fig 7IK The laquoniire aoembiy was sealed in a suhwVss steel outer capsule by welding in argon Samshyples exposed to 61-017 wt (48 at ) Li showed little evidence of penetration except in low-density areas (Fig 12) Samples exposed to Bi-3 wt (48 at ) Li were penetrated more uniformly and the depth
1 Al grapfcilei were fabricated by C ft Kennedy of the Carbon and Graphite Groap Merab and Ceramics Dmnon OftNL
TaMr7l P f t trjtnPnt 01 yinpfcitt fcy lNpMvtfc4ilfcM McapfritttattlbrJtei b r a t t s r c
MISflMM
Graphite demtty Igcml
Ranee of porediam
Maximmn pore diameter chat
conrribnies 10 to total pDtoaly
ltraquogt
nuefration (mils) bulldentiOcatiow
demtty Igcml
Ranee of porediam
Maximmn pore diameter chat
conrribnies 10 to total pDtoaly
ltraquogt K 0ITOU m 3Li
334K 44-25 K 33-3SK 44-26K 44-23K
IM IM 190 ISO 159
01 1 01 2 01 2 01 35 OI 4 5
1 12 I J I J 45
0 5 0 17 8 0 5 5 0 -2 8 0 2 15
Impregnated
NonvMrform penetration in one -gtr two area only
132
133
0MlaquoL-0laquoCrS-l4M9
Flaquo 71 GapMe (bimdasheh lithww) opiate fed asmMy
of penetration increased with increasing pore size and decreasing density Results from previous tests have been inconclusive as to tnr effect of lithium concentrashytion in bismuth on penetration of graphite In the curshyrent series all graphites were penetrated tc a greater extent by K - 3 wt (48 at ) Li than by Bimdash017 wt 9f (48 at ) Li Tests of 10000 hr duration with these graphites are continuing
72 THERMAL GRADIENT MASS TRANSFER TEST OF GRAPHITE IN A MOLYBDENUM LOOP
J R DiSuiano
Although graphite has low solubility in pure bismuth (less than I ppm at 600degC) capsule lest results have shown that higher carbon concentrations are present in Bi -2 wt (38 at ) Li and K-3 wt (48 at ) Li solutions after contact with graphite To avoid the joining proolems associated with fabrication of a graphshyite loop a molybdenum loop was constructed and interlocking tabular giaphite specimens were suspended
in the vertical hot- and cold-leg sections2 In addition to mass transfer of graphite from hot- to cold-leg areas penetration of graphite by bismuth-lithium and mass transfer between graphite and molybdenum were evalushyated
721 WcajMCkaafes
The loop (CPML4) circulated K-24 wt (4 at 3 ) Li for 3000 hr at 700degC (approximately) maximum temperature and 600degC minimum temperature Weight changes in the graphite samples are given in Tables 72 and 7 J After the bismuth-lithium solution was drained from the loop the samples were removed and weighed (after-test column in Tables 12 and 7 3 ) Subshysequently they were clltmdashned at room temperature in ethyi alcohol and in an hO-HNOj (100 ml H 2 O-30 ml 90 HNOj) solution to remove bismuth-lithium adhering to the surfaces of some samples Samples from the cold leg were weighed and then kept in air for two days prior to the alcohol treatment After soaking in alcohol these samples showed larger weight gains than the after-test weight gains and this is attributed to reacshytion of lithium in the sample with moisture in the air during the two-day period AD samples showed large weight gains (33-67) and gains in hot-leg samples were on the average larger than those in the cold-leg samples
122 Compositional Changes
Graphite samples were analyzed before and after treatment with H 2 0 - H N 0 3 and the results are shown in Table 74 These results indicate that bismuth was primarily responsible for the large weight increases and that samples picked up molybdenum but treating them with H 2 0-HNOj completely removed the molybshydenum An electron-beam microprobe analysis of a graphite sample before acid cleaning showed that molybdenum was present on the outer surface of the specimen (Fig 13) Chemical analyses of other graphite samples after acid cleaning are shown in Table 75
Analysts of bismuth-lithium samples from the loop are shown in Table 76 For sampling the hot leg was sectioned so that one sample came from the surface that was in contact with the molybdenum tube wall while the other sample was taken from the interior of the section away from the wall The concentration of carbon in the melt was highest in the sample from the hot leg and both molybdenum ami carbon concentra-
2 i R DiStefano MSR Program Semimnu frofr Rep Pth 28 1975 ORNL-5047pp 140 41
li-3 11 V-IMIOi
-I5H raquobull Mplaquolaquom
F| ) NtMlnltpnorpirMttuiriMwManorMnKluHurinfMltiiid Itlhlum InMwiulli tuniliiiltgtnraquo IIHNI hr M fcjnV
13S
r7J iraquoATJ bull CML4
Wclaquofci If) Welaquofci bullKVU9 I
n mdash t r i bullefore Mi l
After m i
After
bull U k n t w l
After
raquoH04mo
Welaquofci bullKVU9 I bullefore
Mi l After m i
After
bull U k n t w l
After
raquoH04mo ltlaquo) laquoltgt
5 0 4 5 3 0S244 0 1 2 2 0704 02443 54 7 05220 0970 0 95 0S29S 0 3071 59 04494 09551 0933 0X298 OJ304 6
| l gt 0 400 0959 0919 07944 03144 I I 0432 0 3 3 9 0S3O3 07102 0277 4 12 0 4 5 09302 0923 079 03075 7 13 04753 0979 0974 0 7 02933 2 1 0432 09175 09152 075 0302 5 17 04742 09099 0905S 0794 02952 62 IS CS070 09005 0 J 9 5 07975 0290S 57 1 04709 0-raquollaquo9 0142 0 7 1 02459 52 zo 0539 091 M 09149 0 107 0 J 7 J 51 21 0513 OK52 0 J 2 9 072 02453 4 22 0 5 I M 0 M99 0 M59 0759 0J407 4 23 0-539 09103 090 07475 02067 3 24 03405 0 5 4 5 0 4 9 7 07235 01130 33
Top of IKM ley I
Kwlion of hoi leg M laquo | I J M I
rare 0 700C Q0-2OC
Vclaquofti it)
Wclaquoht After Wclaquoht
n m b r t Before After stjfldiHC in am tot two day
After
H 0 -HNO
mcreaK n m b r t
lev lejl
stjfldiHC in am tot two day
After
H 0 -HNO ltIgt I
makohol
27 04 4 0749 0722 0 4 0 01794 39 2 0421 0 2 4 OS4I2 0 2 0 01439 30 29 04717 07793 07913 06433 0 I 7 - 36 30 0477 0713 07239 0291 0151$ 32 31 044 07209 07315 0 3 9 a i 5 4 8 32 32 0427 0729 07744 0647 01 raquo20 3 33 047ft 07193 07 TOO 0331 01543 32 34 0470 0756 0772 0653 012 39 35 0424 073raquo2 0745 0 2 9 0 016 3 3 0423 0749 0759 0343 01520 32 37 0447 07331 07432 0 239 01572 34 3S 04713 07513 0719 0641 01705 3 39 04745 0749 070 0 506 0171 37 40 042 0725 07390 0233 01605 35 41 04725 0745laquo 07J53 0 419 01694 3 42 04100 07427 07525 0652 01726 36 4 3 0476 0720 07401 0647 01712 3
Top of onM leg lempmlvrc 60 60 C ftotlom of cold ley temperalarc 620 630C
136
aMr 74 n a m e d bull bull bull bull bull bull bull ttVli
S jmr t rm HRJIWT Coadiiion Cuacramnunlraquo i
S jmr t rm HRJIWT Coadiiion 3i Li gt
4 (hH WTraquo 4 tbraquort llaquogt
i Ui4d iclt
l a t k a a r d Acid cftcaAGd (bullctnacd Atid ckaacd
4 3 43 40
bull gt 0J I 04
bull11 ltlaquolOI
bullMM ltlaquoMU
tions were higher than were found previously in quart loop tests circuiting Bi-OjOl wt (03 n bulllt Li Quartz loop test 11 contained molybdenum samples and analysis of the bismuth-Uthium solution after test shewed that t contained 25 ppm molybdenum Quartz loop 8 contained samples of three different grades of graphite and the bismuth-tiimum solution contained 10 to 15 ppm carbon after the test
J O B Caiwt j ad L ft Trotter MSR i Awfr Rep Air _ 1971 OKSL-4 p i - 3
V1330SS
BACKSCATTERED ELECTRONS
- - - Oraquo J
V
8 i M a X-RAYS Me L X-RAYS
Ffcgt 7J EMCWIM kmn) laquoeaaninj M H J M r laquoapnlaquo taawnf to Mnmrth Vnw IA) a backmttcrcd electron picture of sample tarface dark material n tnpfcitc and bright material is bianulh and malybdemHM as indicated by iff)and O
117
Tank 7 3 C k a m anakwaaf p i j i i i r bull bull | l i r f c mdash C F M L - 4
bull bullbe U Mo
1 Hot kg 37 0J5 ltOJraquol ltraquo H o i k s 42 044 lt0OI
15 H o i k 4 04 ltO01 l raquo Hocks 3 0 J 5 lt 0 0 1 24 Hotks 2i 025 ltOOI ^ T C o M k f J 0 3 5 ltO0 I 31 C o M k f 21 0 2 5 lt00I 3 C o M k f I t 02 ltoot 42 CoMkc 23 02 lt0Jraquo
Sampio plusmni deaneu m H OMNO prior to a i r
Tabk7 A ^ s t t t a M M i
CoaceaiDiMt
Sample location C ippa l
Mo tppau
Li fit
Hot k f icowl Kof kg iflwfaotf r
CoM kg loner
43 10 24
17 102
4
23 3 0 1
On a raghl bam Interior tampk
Surface simple in contact raquonb molyb i fcmdash rabe laquoaH
Selected graphite samples from hot- and cold-leg regions are shown in fig 74 The white phase distribshyuted throughout the samples is bismuth these samples were add cleaned and it is evident that bismuth was dissolved from the area near the surface Molybdenum samples from hot- and cold-leg regions are shown in Fig 75 Surface layers measuring 0015 to OJ025 mm (0 6 -1 mil) thick were found on the hot-kg sample In some areas ttwie was a single layer while a double layer was found in other areas Electron-beam mkroprobe analysis indicated the single layer andor outer layer to be primarily molybdenum This layer was much harder than the base metal (1000-1200 DPH compared with about 200 DPH) indicating that it is probably MojC Where there is a double layer the outer layer appears to be MojC but the inner byer n primarily bismuth One explanation is that the MojC layer cracked andor spailed allowing the entry of bismuth which did not drain when (he lest was terminated The molybdenum sample from the cold leg also exhibited a surface layer
i o raquo f l u C mm t h k k i gt i i 33S SSSH3 S CCSSpSKBOS to that found in the hot leg Samplrs of molybdenum from hot and cold legs have been submitted for chemishycal analysis
The prindtMl objective of this experiment was toeval-uate temperaiure-gtadieai mass transfer of graphite in bismuth umijiuiug a retainer high concentration of lithium However mass transfer data were obscured by the gross pickup of bismuth by the graphite samples Previous capsule and quartz loop tests with ATJ graphshyite had indicated much less intrusion of the graphite by bismuth than occurred in the molybdenum loop test This suggests that the permeabihty at ATJ graphite to bisnush-hdnum does not depend simply on the po-rc^y of the graphite It is generally accepted that some fracioa of the pores in graphite is effectively sealed off 7uraquo contributes nothmg to flow Therefore the conshynected pore system controls the penneabraty The shape of the connected pores influences the type of flow and die length of the path the fluid takes through the sample For a nonwettiug liquid the external presshysure forcing the liquid into the pores 1 must overshycome the surface tension of the liquid This defines a critical pore radius r( and unt l the pressure exceeds the value given by
lrraquo=27costfr c ltgt
where y is the surface tension and 9 the wetting angle the pore cannot support flow Thus for a given - I f rc is the minimum pore size that w H be penetrated In both the metal and quartz thermal convectica loops IT is determined by the argon overpressure ( lt l atm) and the height of btsmmh-fcthium solution above the sample and these wne essentially the same in both types of tests Temperature affects both a and 9 but all o( the tests were operated under similar thne-temperature-^r conditions Graphite samples used hi the quartz too tests had almost four limes the surface area o f the tabushylar specimens used in the current test but they were almost three times as thick The larger surface area of the quartz loop specimens should have increased the relative amount of bismuth-lithium intrusion but the greater thickness of these samples would reduce the pershycentage increase ATJ graphite samples from the quartz loop tests increased in weight by 01 to 06 wt ar far less than the 30 to 67 wt increases noted hi samples from the current loop test Thus specimen geometry alone does not seem to explain the differences noted However the surface tension o and wetting angle 9 were
138
3
i 8
a
139
Y-I33405
- n r fimfir nriiiTii ifiari Bottom of Hot Leg 600C Bottom of Cold Log 620C
f 75 MolyMniBin tube waN from thermal comectkm loop CPML-4 thai cin slated Bi-24raquo Li and contahnd graphite ^CCMCHS
probably different because the lithium concentrations of the bismuth-lithium solutions were different and molybdenum was present in the current test It is posshysible that the presence of molybdenum on tie surface of the graphite had a marked effect on the contact angle 0 fn an earlier series of tests the bismuth content of graphite specimens was much higher when they were tested in molybdenum capsules instead of graphite capshy
sules4 Accordingly data on the wetting of graphite by-bismuth containing lithium and other constituents of processing solutions would be useful for predicting the resistance of graphite to penetration
4 J R PiStefano and O B CavmMSR Profnm Semumnu Pmgr Rep Feb 2K 1975 ORNL-SM7 pp 137 39
Pan 4 Fuel Processing for Molten-Salt Reactors
J R HightowerJr
The activities described in this section deal with the development of processes for the isolation of protacshytinium and for the removal of fission products from molten-salt breeder reactors Continuous removal of these materials is necessary for molten-salt reactors to operate as high-performance breeders During this report period engineering development progressed on continuous fluorinators for uranium removal the metal transfer process for rare-earth removal the fuel recon-stitution step and molten salt-bismuth contactors to be used in reductive extraction processes Work on chemistry of fluorination and fuel reconstitution was deferred to provide experienced personnel for the prepshyaration of salt for the TeGen-2 and -3 experiments (Sect 617)
The metal transfer experiment MTE-3B was started In this experiment all parts of the metal transfer process for rare-earth removal are demonstrated using salt flow rates which are about 1 of those required to process the fuel salt in a lOOO-MW(e) MSBR This experiment repeats a previous one (MTE-3) to determine the reasons for the unexpectedly low mass transfer coeffishycients seen in MTE-3 During this report period the salt and bismuth phases were transferred to the experishymental vessels and two runs with agitator speeds of 5 rps were made to measure the rate of transfer of neo-dymium from the fluoride salt to the Bi-Li stripper solushytion However in these runs the fluoride salt was enshytrained at low rates into the LiCl which resulted in depletion of the lithium from the Bi-Li solution in the stripper Fuel-salt entrainnient was unexpected since no entrainment was seeii in experiment MTE-3 under (as far as can be determined) identical conditions The Measurement of mass transfer coefficient in these first tvo runs was not compromised by the cntrainment The measured mass transfer coefficients were lower than
predicted by literature correlations but the values are comparable to those obtained from experiment MTE-3
Mechanically agitated nondispersing salt-metal conshytactors of the type used in experiment MTE-3B are of interest because entrainment of bismuth into the fuel salt can be minimized because very high ratios of bisshymuth flow rate to salt flow rate can be more easily handled than in column-type contactors and beczuse these contactors appear to be more easily fabricated from molybdenum and graphite components than are column-type contactors Attempts were made to measshyure entrainment rates of fluoride salt in bismuth and entrainment rates of bismuth in fluoride salt under conshyditions where the phases were not dispersed and under conditions where some phase dispersal was expected These measurements were made in the o-tn-diam (01 S-m) contactor installed in the Salt-Bismuth Flow-through Facility The results indicate that mild phase dispersal with in concomitant high mass transfer coeffishycients night be allowable in the reductive extraction processes We are continuing development of methods for measuring mass transfer coefficients in mercury-water systems to learn how to scale up contactors which would be used with salt and bismuth
A nonradioactive demonstration of frozen salt corshyrosion protection ir a continuous fluorinator requires a heat source that is not subject to attack by fluorine in the fluorinator To provide such a heat source for future fluorinator experiments we have continued our studies of autoresistance heating of molten salt During the report period we have completed new equipment for studying autoresistance heating of molten salt in a flow system similar to a planned continuous fluorinator exshyperiment three preliminary runs have been made with the equipment The design was started for a facility for developing continuous fluorinators and equipment is
140
141
being installed for an experiment to demonstrate the effectiveness of frozen salt for protection against fluoshyrine corrosion
The uranium removed from the fuel salt rraquogt fiuorina-tion must be returned to the processed salt in the fuel reconstitution step before the fuel salt is returned to the reactor An engineering experiment to demonstrate the fuel reconstitution step is being installed In this experishyment gold-lined equipment will be used to avoid introshyducing products of corrosion by U F and U F S Alternashytive methods for providing the gold lining include elecshytroplating and mechanical fabrication The choice beshytween the two depends on availability of gold from fcRDA precious-metal accounts and the price of gold from the open market Instrumentation for the analysis
of the vessel off-gas streams has been installed and is being calibrated
Future development of the fuel processing operations wdl require a large facility for engineering experiment A design report is being prepared to define the scope estimated design and construction costs method of accomplishment and schedules for a proposed MSBR Fuel Processing Engineering Center The building will provide space fcr preparation and purification at salt mixtures fcr engineering experimenis up 10 the scale required fcr a I0OO-MW(e) MSBR and for laboratories maintenance areas and offices The estimated cost of thrs facility is SISjOOOjQOO and authorization is proshyposed for FY 1978
R Engineering Development of Processing Operations
J R Miditower Jr
81 METAL TRANSFER PROCESS DEVELOPMENT
HC Savage
During this report period the salt and bismuth solushytions were charged to the process vessels of the metal transfer experiment MTE-3B Two experiments were completed in which the rate of removal of neodymium from molten-salt breeder reactor fuel salt (72-16-12 mole LiF-BeF 2-ThF 4) was measured
The MTE-3B process equipment (Fig 81) consisted of three interconnected vessels a 14-in-diam (036-m) fuel salt reservoir a 10-in-diam(025-m)salt-metal conshytactor and a 6-in-diam (015-m) rare-earth stripper The salt-metal contactor is divided into two compartshyments interconnected through two 05-in-high lt 13-mm)
I H C Savage Bngmeenng Development Studies for Molten-Sat Breeder Reactor Processing Xo -0 ORNL-TSM870 (in preparation)
by 3-in-wide (76-mm) slots in the bottom of the divider Bismuth containing thorium and lithium is cirshyculated through the dots Thus fluoride fuel salt was in contact with the Bi-Th in one compartment and LiG was in contact with the Bi-Th in the other compartshyment The stripper contains lithium-bismuth solution (5-95 at ) in contact with the LiCl Mechanical agitashytors having separate blades in each phase in the conshytactor and stripper were used to promote mass transfer across the three salt-metal interfaces The fluoride fuel salt was circulated between the reservoir and contactor by means of a gas-operated pump with bismuth check valves The LrCl was circulated between the stripper and contactor by alternately pressurizing and venting the stripper vessel
The bismuth-thorium phase was circulated between the two compartments of the contactor by the action of the agitators and no direct measurement of this flow rate was made during the experiment however measshyurements made in a mockup using a mercury-water system indicated that the Bi-Th circulation rate between
ORWL-06-71 1471
AWTATORS-
LEVEL ELECTRODES
LiT-raquoF--TMU Li-a
FLUORIDE SALT
RESERVOIR
SALT- KCTAL CONTACTOR
M M EARTH STRIPPER
F 81 Flow diagram for metal trmrfcr experiment MTC-3
142
143
the two compartments should be high enough to keep the concentration of rare earths in both compartments essentially the same2 This was found to be the case in the two experiments in MTE-3B
In this experiment neodymium is extracted from the fuel carrier salt into the thorium-bismuth solution Next the neodymivm is extracted from the thorium-bismuth into molten LiCI and finally (he neodymium is stripped from the LiCI into bismuth-lithium alloy
Operating variables in the experiment are
1 the flow rate of the fluoride fuel salt between the fuel salt reservoir and the contactor
2 the flow rate of the lithium chloride salt between the contactor and the stripper vessel
3 the degree of agitation of the salt and bismuth pluses in the contactor and stripper
4 the amount of reductant (lithium) in the bismuth phase in the contactor
The operating temperature of the systen is ^-650degC Overall mass transfer rates for representative rare-earth fission products are determined by adding the rare earth to the fluoride fuel salt in the reservoir and observing the rate of transfer of the rare earth across the three salt-bismuth interfaces as a function of time by periodic sampling of all phases
2 H O Weeren and L E McNcese Engineering Developshyment Studies far Molten-Sail Breeder Reactor Processing So 10 ORNL-TM-3352 (September 1974) pp 57 59
[taring the course cf the experiments the concentrashytions of neodymium in each phase were deteiiaiacd by counting the 053-MeV gamma radiation emitted bv 4 T N d tracer added to the neodymium origmaBy in the fuel salt This provided a rapid method for fallowing the transfer rate More accurate data necessary for calculatshying the overal mass transfer coeffiaeats at each of the three salt-metal interfaces were obtained by analyzing samples of the salt aM bismum phases for total teo-dymium via an isotonic dilution mass spectrometry technique Use of this technique avows measurement of neodymium concentrations as low as OJOI ppm (wt)
811 of Salt J to Metal MTF3
The quantities ot salts and bismuth charged to the process vessels of experiment MTE-3B are listed in Table 81 AD internal surfaces of the carbon-steel vesshysels were hydrogen treated at 650degC for V7 hr to reshymove any oxides prior to the addition of the salt and bismuth solutions The auxiliary charging vessels used in the additions were also hydrogen treated Subsequently a purified argon atmosphere was maintained in all the vessels to prevent oxide contamination (via ingress of air or moisture) of the vessels and process solutions
The charging vessels were IO-in-diam (0_25-m) carboa-steH vessels o f about 22 liters (0022 m 3 ) in volume equipped with electric heaters for melting the salts and bismuth Nozzles and access ports were pro-
Tabie8l Qwtit iet ot salts and tnsmmtk for o u M i w f t MTE-3B
Material Vessel Volume at
650C (liters)
Wesgh (kg) f-moles
Fluoride fuel salt Reservoir 294 970 5lt (72-16-12 mole LiF-BcF -ThF)
Fluoride fuel salt Contactor 31 102 161 (72-16-12 mole LiF-BeF-ThF)
Bismuth-thorium | M 500 ppm (wt) Th Fluoride salt 29 276 132 MO ppm Li| side of contactor
Bismuth-thorium [M500 ppm (wl)Th LiCI side of 35 33 161 M 0 ppm Li| contactor
Lithium chloride Contactor 29 43 101
Lithium chloride Stripper 38 56 132
Bismuih 5 at lithium in Stripper 43 418 200 stripper
Demiliev at 650C fluoride fuel salt 330 gcc LiCI = 1 AS gcc Bi 96 gcc Mole weight = 632 g
144
video for the addition of the salts and bismuth argon and hydrogen purge gas ones and hues required to transfer the salt and bismuth phases into the process vessels
Bismuth hydrogen treated in the charging vessel to remove oxides was the first material to be added to the contactor The fluoride fuel salt was then contacted in the charging vessel (using argon sparging) with a bismclaquoi-OIS wt thorium solution (50 of Th satushyration) for several days prior to transfer into the fuel-salt reservoir and the fluoride salt compartment of the contactor Thorium metal (01197 kg) was then added to the 614 kg of bismuth in the contactor This quanshytity of dtorium is about 50 of the amount that would be soluble and was calculated to produce a lithium conshycentration ot ^-40 ppm (wt) in the thorium-bismuth phase in the contactor based on previously reported data1 on the distribution of thorium and lithium beshytween molten bismuth and fluoride fuel -alt
FoBowing the additions of bismuth to the contactor and the fluoride fuel salt (72-16-12 mole LiF-BeF2-ThF 4) to the contactor and fuel-salt reservoir a new charging vessel was installed for makeup and charging of the bismuth-5 at lithium to the stripper and the LiCI to the contactor and stripper First bismuth was added to the charging vessel and was hydrogen treated to remove oxides by sparging with hydrogen at v-oOOC (873degK) for laquoraquo7 hr The charging vessel contained 6787 kg of bismuth to which was added 0120 kg of lithium metal to produce the bismuth-5 at lithium for the stripper Part of the bismuth-5 at lithium solution (41 amp kg) was then transferred into the stripper vessel
Thorium metal (0109 kg) was added to the 26 kg of bismuth-lithium solution remaining in the charge vessel and 1588 kg of LiCI that had been oven dried at 200degC (473degK) was added to the charge vessel The bismuth-lithium-thorium and LiCI phases were sparged with argon using a gas-lift sparge tube for four days The LiCI was then transferred into the LiG side of the conshytactor and the stripper vessel
The salt and bismuth solutions were filtered through molybdenum filters [^30 u (30 X I0~ 5 m) in pore diameter] installed in the transfer lines during transfer
- from t^e charging vessels into the MTE-3B process vessels
812 Run Nd-I
For the first run in MTE-3B 3300 mg of NdF (2360 mg of Nd) was added to the 97 kg of fluoride fuel salt (72-16-12 mole LiF-BeF2-ThF4) in the fuel salt resershyvoir on June 6 1975 The neodymium contained 722 mCi of TNd tracer (tVi - 11 days) at the time of
addition The neodymium concentration in the fuel salt in the reservoir was calculated to be 24 ppm (wt) which approximates that expected in the fuel salt of a single-region lOOO-MWie) MSBR Neodymium was chosen as the representative rare-earth fission product for the first series uf experiments in MTE-3B for several reasons
1 results could be compared with those obtained using neodyrahnn in the previous experiment4 MTE-3
2 Sd tracer used for following the rate of transfer of neodymiuni has a relatively short half-life (11 days) which would prevent excessive levels of radioshyactivity in the experimental equipment as additional neodymium containing 4 7 N d was added to the fuel salt during the expert-went
3 neodymium is one of the more important trivaknt rare-earth fission products to be removed from MSBR fuel salt
An attempt was made to start the first run (Nd-I )on June 91975 However a malfunction in the electronics of the speed control unit for the stripper-vessel agitator prevented startup After this unit was repaired run Nd-1 was started on June 15 1975 and the scheduled period of operation (100 hr) was completed on June 20 1975 Operating conditions of run Nd-I were 650 to 660CC (923 to 933degK) 5 rps agitator speeds in both contactor and stripper fluoride salt flow rate of 35 ccmin (58 X I 0 1 m 3sec) and LiCI flow rate of 12 litersmin (20 X IO 5 nrsec)
After 100 hr of fluoride salt and LiG salt circulation the fluoride salt circulation was stopped and the run was continued for 16 hr This was done to observe the expected large decrease in the concentration of neoshydymium in the smaller amount of fluoride salt in the contactor (102 kg) as compared with the 1072 kg contained in both the contactor and reservoir These data would provide a more accurate measure of the rate of transfer of neodymium across the fluoride salt-bismuth-thorium interface
Finally the circulation of LiG was also stopped The agitators in the contactor and stripper vessels were then operated for ^24 hr over a three-day period (8 hr each day) to allow the salt and bismuth phases to equilibrate in an attempt to determine neodymium distribution coefficients between the phases
3 L M Ferris Equilibrium Distribution of Actinide and Lanthanide Elements Between Molten Fluoride Salts and Liquid Bismuth Solutions Inorg Nucl Chem 32 2019 35 (1970)
4 Cfiem Ttchnol Dir Annu Prop Rep March 31 1973 ORNL-4883p 25
145
The experimental equipment operated safisfacturBy throaghout ran Nd- I AH operatiag variables were maia-taiaed at desired coaonioas Results obtained during run Nd-I are discussed in Sect 814
SI J Ran Nd-2
Run Nd-2 was done with the sam operating condishytions as ran Nd-I except for run deration (119 hr inshystead of 100 hrraquo Prior to run Nd-2 3590 mg of N d F
(250 tog of Ndgt coalaaaag 101 mCi of 4 7 N d tracer was added to the 97 kg of fad salt in the reservoir Including the ncodVaaum leinainaig in the furl salt at the end of ran Nd- I estimated to be 18 ppra ltwt) the neodymium concentration in the fuel salt in the resershyvoir at the start o f run Nd-2 is estimated to be 45 pom The neodynaum concentration in dte fuel salt in the contactor is estimated to be 9 ppm at the start of run Nd-2 We are uncertain of the amounts of neodymium in the other phases at the beginning of run Nd-2 as discussed in Sect 814
Run Nd-2 was started on July 13 1975 and was tershyminated on July 19 1975 after 139 hr of operation During the first 50 hr of operation the rate of transfer of neodymium into the lithium-bismuth phase in the stripper appeared to be about the same as observed during run Nd-I based en counting of the | 4 7 N d tracer in samples taken at regular intervals After about 60 hr of operation the transfer of neodymium into the bismuth-lithium phase in the stripper suddenly stopped and it was observed that neodymium was being exshytracted from the bismuth-lithium phase in the stripper into the LiCl in the stripper and contactor During the run a significant decrease in the emf between the stripshyper vessel and the contactor occurred (from ^160 mV to ^25 mV over a 30-hr period) indicating loss of lithshyium reductant from the bismuth-lithium phase The run was terminated after 139 hr of operation when it beshycame clear that useful information could no longer be obtained and it appeared that fluoride salt was being entrained into the LiCl in the contactor
814 Discussion of Results
Subsequent investigation and results of chemical analshyyses of samples of the salt and bismuth phases indicate that fluoride fuel salt was being entrained into the LiCl in the contactor throughout both runs Nd-I and Nd-2 Estimates of the amount entrained are shown below
Estimated amount of fluoride a l l transferred into LiCl Baas of estimate
Nd-I | I 0 laquo hr) Nd-I and -2 (Jul hr)
0292 kg Fluoride in IiO phase 0607 kg Thorium in B I - L I phase 0400 kg Increase in LKI level in
stripper
Based j a flaoriae analyses of 1X1 maple T taken daring nm Nd- I the enuaaaaeat of flaoride salt appears to have occurred at a relatively constant rate throaghoat the ran The total amount of neodyaaam which transshyferrer into the Li-K phase in the stripper daring ran Nd-I is estimated to be 300 mg The aaaoaat of aeo-dynaam contained in the entraiaed fad salt isestiuated to be 6 mg That most of the neodynaam which transshyferred into the Li-Hi in the stripper vessd was by mass transfer rather than as a result of eatiaauaeM
The reason for the ubstivtd enfaauaeat is not dear at present One explanation K that the 50-rps agitator speed is saffident to cause enirainment (entrainmeat of flaoride salt into the chloride salt occurred in the preshyvious experiment MTE-3 at 67 rps bat not at 5JO rps) Experiments are in piogiess for deternaaing whether this explanation is correct and results to date indicate that entranirmi does not occur at 3 3 rps Further experiments in MTE-3B w i l depend on determining the reason for the unexpected entrainment of fluoride nt into the LiCl- However it appears feasible to continue rare-earth mass transfer experiments in MTE-3B by removing the LiCI (contaminated with fluoride salt) and the Li-Bi solution from the stripper vessd after which purified LiCl and Li-Bi solution will be added to the system
The main nurpose of the metal transfer experiment is to measure mass transfer coefficients for the rare eanhs at the various salt-metal interfaces in the system and to determine whether a literature corrdation5 (based on studies with aqueous-organic systems) which relates many transfer coefficients to the agitator speed and other physical properties of the system is applicable to molten salt bismuth systems Data obtained from run Nd-I have been analyzed and estimates have been made of overall mass transfer coefficients for neodymium at the three salt-metal interfaces Even though entrainment of fluoride salt into LiO occurred during run Nd- I it is believed that the mass transfer rate for neodymium was not 5ignificantly affected The concentration of fluoride in the LiCl at the end of run Nd-I was vl_ wt 1 or 003 mole fraction Based on previous studies6 the disshytribution coefficient ) for neodymium between the molten bismuth-thorium solution and LiCl (mole fracshytion Nd in bismuthmole fraction Nd in LiCl) would be decreased by ^ 2 0 7 while the distribution coefficient for thorium would be decreased by a factor of ^150 This would result in a decrease in the separation factor
5 J B l-ewii Chan En Sri 3 24S 59 119541 6 I M Ferris el raquo Distribution of Lanthamde and
Actinide Klements Between Liquid Bismuth and Molten IKI-Iil- and liBr-lil Solutions Inorg ucl Chart 34 313 20(1972)
146
were t in
VIO to vIO1 i transferred
bull t o the Lid The ate of leaver of neodynuua across the three
byaaslysesofi the m Two analytical i
(1) coasting of the OS34acV by the 4 N i tracer aad (2)iKgttopicduu-
spectroaaetry luaed on ccejufhag of the 4 T N d tracer a aaMeriai buuare of the t w t j i i w of gt95 obtained at the end of run Nd-1 indicated that about 11 of the niudjununa mfrinaMj added to the fuel salt icaenvar had beea transferred iato the LMI irautioa at the stripper
The counting trchaiqf is a rapid method aad pro-oa the rate of transfer wide the mas llwwcui it does ant provide the
required for calculation of the overal mas transfer coefficients particalariy in the K-Th aad Lid
bull the contactor aad stripper vessels in which the less than 1 ppm
(wt) The isotonic ddutioa analysis is capable of accushyrately determining neodynmm conccntntioa down to -VOJOI ppmfwt) and resorts obtained from the isotopic duvtioo tednaque for the Bs-Th and LiCI phases were used for calculations of the overall mass transfer coeffishycients
Values for distribution coefficients for neodymium at the thru salt-metal internees were measured at the end of run Nd-1 for comparison with those calculated from the dau of Ferris3 bull (Table 82) The experimental values are in reasonable agreement with the calculated values in the absence of fluoride contamination indicashy
ting that the distrnVstsoa coefficieau for neodynnum were not seriously affected by the entKnuncnt of the fluorine sah into the chloride
Data obtained during run Nd-1 were analyzed by inuahawiiui solution of seven tune-dependent differenshytial mm rial twlanu equations (Fig 8 J ) that relate the
v i imdash F t laquo r V
raquo i W W F a laquos-X4gt
V j j l laquo bull Klaquoa (X-IVCraquo)-F(Xs-)^
V - MOLAR VOLUME OF EACH PHASE
F bull FLOW RATE MOLESSEC
7 L M Perm et d Distribution of Lanthannte and Actiniae Element Between Molten Uthium Halide Salts and Liquid Msmuth Solutions Inorg Piuci Oirm 342921 -33 lt1972)
OLOLDc RARE-EARTH DISTRIBUTION COEFFICIENTS MOLESMOLE
A AREA AT EACH INTERFACE CM
TaMrSJ Dutrwatioa coeffionrta for mod m msit iauat MTE-3B ran Nd-1
Salt-metal interface Calculated Experimental
Fluoride salt-Bi-Th LaO-Bi-Th LiQ-Li-Bi
0006 094
3-5 X 10
0013 064
gt I X I0raquo
Distribution coefficient laquo (mf Nd in bismuth)(mf Nd in salt) ^Conditions 6S0C (923degK) Li concentration in Bi-Th 40 ppm Li concentration in Li-Bi = 5 at no fluoride in LiG phase
K I KbdquoK gt RARE- EARTH OVERALL MASS TRANSFER COEFFICIENT CMSEC
X gt RARE- EARTH CONCENTRATION IN EACH PHASE MOLESCM
EQUATIONS USEO TO CALCULATE MASS TRANSFER COEFFICIENTS FOR METAL TRANSFER EXPERIMENT
MTE-3B
F raquo S X Equations awd to calculate maw traaafer coeffishycients for the metal Mifer p r a m experiment V volume of each phase x - rare-earth concentration l = lime A - mass transfer area F raquo flow rate D bull rare-earth distribution coeffishycient K = overall mass transfer coefficient
147
rate at which the rare earths r ~ transferred through the several stages to the distribution coefficients of the tare earth the mass flow rates and the mass transfer coeffishycients at each salt-metal interface The set of equations was solved using a computer program by selecting values for the mass transfer coefficients which resulted in the best agreement between the experimental data on rate of change of neodymium concentration in aB phases in the system and the calculated values Several trial-and-error iterations were required using adjusted values of mus transfer coefficients until a best-fit solution was obtained
The final calculated results for run Nd-1 are shown in Table 83 where the values for the overall mass tkjnsfer coefficients are given and are compared with values calshyculated by the correlation of Lewis5 The coefficients are lower than predicted and are similar to results obtained in the previous experiment MTE-34 Final analytical results for run Nd-2 are not yet available However for the first SO hr of operation the rate of accumulation of neodymium in the Li-Bi solution in the stripper appeared to be similar to that observed in run Nd-1 The significance of these absolute values of mass transfer coefficient cannot be assessed until the scaling laws in this type of contactor are known
8 L E McNeeje Engineering Development Studies )or Molten-Salt Breeder Reactor Processing o II ORNL-TM-3774 (in preparation)
8 2 SALT-MSMUTH CONTACTOR DEVELOTMENT
CH Brown Jr
Mechanically agitated nondispening salt-bismuth conshytactors are being considered for the protactinium removal step and the rare-earth removal step in the reference MSBR processing plant flowsheet These conshytactors have several advantages over packed-column salt-bismuth contactors
1 they can be operated under conditions that minimize entrainment of bismuth to the fuel salt returning to the reactor
2 they can be fabricated more economically from graphite and molybdenum components
3 they can handle more easily large flow-rate ratios of tismuth and molten salt
Experimental development of stirred interface contacshytors is being carried out in two different systems a facility in which molten fluoride salt is contacted with bismuth containing a dissolved reductant and a system in which mercury and an aqueous electrolyte phase are used to simulate bismuth and molten salt These two systems and the development work performed during this report period are described in Sects 821 and 822
Table 8J Oven mass transfer coeffkieM for iteodymmm m metal master experiment MTE-3B ran Nd-1
A (mmsec) A (mmsec) A (mmjecr
Measured1 Predicted value value ltlt)
Measured Predicted value value Cr)
Mease bdquod c Predicted value value i^)
00035 39 025 20 013 25
Based on the neodymium in the salt phase 1 I I
bmdash~ - mdash mdashmdashmdash at fluoride salt -Bi -Th interface
I D B
I l
at LiCl-Bi-Th interface
a LiO - Li-6i interface A j km k9Ds
= individual mass transfer coefficient fluoride sail to bismuth - individual man transfer coefftcien bismuth to Tuoride sail = individual man transfer coefficient bismuth In lithium chloride k - individual mass transfer coefficient lithium chloride to bismuth
where
DA - distribution coefficient between fluoride salt and bismuth Dg - distribution coefficient between chloride salt and bismuth Oc distribution coefficient between chloride salt and lithium-bismuth
cAgitator speed is 50 rps
MS
S 2 I Expernieafe win a fecsnmkaly Agitated Nnaaraquoprning Contactnr bull the Salt bull f a i t h
Flolaquortuumgt FariSty
Operation of a facility has continued in which mass transfer rates are being measured between molten LiF-BeF 2 ThF 4 (72-16-12 mok )and molten bismuth m a mechanically agitated nondispeising contactor The equipment consists of a graphite-lined stainless steel vessel salt and bismuth feed and receiver vessels and the contactor vessel h the first of these the salt and bismuth phases are stored between runs The other vessels allow for treatment of the phases with HF and H The comactor consists of a 6-ltn-diain carbon-steel vessel conta rang four I-in -wide vertical baffles The agitator consists of two 3-in-dhm stirrers having four noncanted blades A ^-in-dtam overflow at the intershyface allows removal of interfacial films i f present with the salt and metal effluent streams During a run the salt and bismuth phases are fed to the contactor by conshytrolled pressurization of the respective feed tanks the phases return to the receiver vessels by gravity flow A detailed description of the facility and operating proshycedures has been previously reported A total of nine mass transfer runs have been completed to date along with one hydrodynamic run intended to determine the amount of entrainment of one phase into the other at a sties of different agitator vxeds Results from the nine mass transfer runs have been previously reported ~ i
The experimental proceduie for and results obtained from the hydrodynamic run and treat men of the salt and bismuth with HF and H 2 are discussed in the reshymainder of this section
Experimental operation daring the hydrodynamic ran The hydrodynamic run was performed with salt and bismuth flow rates of M 5 0 and M 4 Q ccmin respectively The agitator was operated at three difshyferent speeds during the run 250310 and 386 rpm At 250 and 310 rpm three sets of unfdtereJ salt and bisshymuth samples from the contactor effluent streams were taken at 4-min intervals Three sets of unfiltered efshyfluent samples were aiso taken with the agitator operatshying at 386 rpm but the samples were taken at 2-min intervals
To avoid contamination of the sample contents with extraneous material the sample capsules were cleaned of foreign matter by the following procedure Gross amounts of salt or bismuth were first removed with a file then the sample capsule was polished with emery cloth and finally (he capsule was washed with acetone
The sample capsules were then cut open with a tubing cutter and the contents of each sample were drilled out
and visual)- inspected for the presence of one phase in the other Ho such evidence of gross entramment was found h some of the salt samples small flecks of metal were noticed which were probably small pieces of the sample capsule produced during the dnamg operation The contests of each sample were then sent to the Ana rytical Chemistry Division for dttuiiannion of brsrmnh present in gt salt samples and berynram present in the bismuth samples h is assumed that any berynmm present in the bismuth is mdkstive of entrained fluoride salt The results of these analyses are given in Table 84 The bismuth concentration in the salt samples shows a general decrease with increasing sarrer speed widi very low values occurring at the highest stirrer speed It also seems evident that the bismuth concentration in the salt phase may have been a function of the run time since after the fourth sample the bismuth concentration reshymained at a relatively constant value of 50 plusmn11 pom which is quite different from the values reported for the first four samples which ranged from 1800 to 155 ppm
These results are significantly higher than those of LindauerJ who saw less than 10 ppm of bismuth in
9 J A Klein el al tnaraquoeerme Development Stmmes far I M l d i U t Breeder Reactor hocesnm So bull ORNL-TS-463 Italy 1975) pp 2 3S
10 C H Brown Jr Engmttii-t Development Studies for Molten Salt Breeder Reactor rYoceomf So 21 ORNL-TM-4X94 (in preparation)
11 J A Kkai tnemeermw Drreiopmenl Studies of Molten-Smll Breeder Reactor Procenmt So IS ORNL-TM-469 (September 1974) pp I 22
12 C H Brown Jr Enjmerrmt Development Studies for Hoten Salt Breeder Reactor rVncezshu Vo 20 ORNL-TM-4810 (in preparation)
13 R B LindraeT fmjmeetmf Drreiopmenl Studies of Molten Salt Breeder Reactor Proceowtt So 17 ORNl-TM-41711 (m preparation)
TaWeS4 Kwmyraquoof ^aXmmhwmmmtn
Agitator speed Bi sample Be in Bi Sail sample Bi in salt (rpm) number (ppm) number (ppm)
250 42 215 437 100 250 429 125 43 205 250 430 215 439 155 310 431 85 440 270 310 432 910 441 53 10 433 442 34
36 434 110 443 64 36 435 175 444 54 36 436 50 445 43
149
fluoride salt in comact with b i t iu fh in several different contacting devices- It is likely that sample i nniiuuni tioa is a contributing factor to the high bcrmdashrh concenshytrations measured Three possible sources of sample coataaunaboa have been reported
I timtjuunitiou by withdrawing Imdashparr through a sample port which has been in contact wkh bismuth
analytical laboratory by the use of equipment roushytinely used for bismuth analyses
3 ctrwfuttiiuTmutftoit from bull hwy^CTWffy vt^tt^f^n^i^^^^UKttf material laquohkh may be floating on the salt surface
Since no maximum peiHUSMuk rate of bismuth eMram-ment in the fuel salt going to the bism ah removal step or m the salt returning to the reactor from the fuel processing plant has been set it is difficult to assess the significance of these results However the bismuth conshycentrations in the salt do not seem to be inordatttelv high at the highest stirrer speed and it seems Bkefy that some degree o f phase dispersal might be tolerated ia order to achieve higher mass transfer rates
The beryflium concentrations in the bismuth samples at each agitator speed show both high and low values with no discernaWe dependence on agitator speed These results agree well with previously reported data1 for beryllium concentration in the bismuth phase during mass transfer runs in this system at agitator speeds of 124 180 and 244 rpm Previous experiments with water-mercury and organic-mercury systems suggest entrainineni of the light phase into the heavy phase at an agitator speed of about 170 rpm The concentration of beryllium in the bismuth phase is not significantly different from previous results observed at lower agitashytor speeds The effect of entrsined fluoride salt in the bismuth would be most detrimental in the metal transshyfer process where fluoride salt in the chloride salt phase decreases the separation factors between thorn m and the rare-earth fission products
H -HF treatment of salt and bismuth The mass transshyfer runs completed to date in he salt-bismuth contactor have all been performed under conditions where the controlling resistance to mass transfer is in the inter-facial salt film One final mass transfer run will be pershyformed in which the bismuth-film mass transfer coeffishycient is measured In preparation for this run the salt and bismuth in the graphite-lined treatment vessel were treated with HF diluted with H 2 to oxidize the reduc-tants present in the bismuth phase The procedure used was essentially that reported previously14 The salt and bismuth at -v-oOOC were sparged with 25 scfh of 30 (mole) HF for 9 hr The HF utilization decreased from
7 5 at the 1 njiiiiini of treatment to 3 5 during the final 2 hr of treatmat Analysis of the ash and bismuth phases before and after treatment with HF and H 2 inshydicated that esaeatiaty a l of the rr duct ant in the bisshymuth phase was oxidized by hydrofluormatioa The mmtmm distribution ratio decreased from 740 molts mole prior to the treatment to OJ03 molemole after the HF-Hj treatment
L U ---r--8 iiiiiT I M I I I M M I U I I - j
We have continued development of a mrrhmii dlj agitated nondispersmg two-phase contactor wing an aqueous electrolyte and mercury to srmmatf mohea salts and bismuth
As previously reported1 we have investigated the feasibility of using a pobrographk technique for measuring electrolyte-film mass transfer coefficients in this type of contactor During this report period we have
1 tested three different anode materials 2 produced cathodk polarization waves corresponding
to the reduction of F e compkxed widi excess oxalate ions at the mercury surface
3 obtained and calibrated a slow-scan controDed-potential cyclic volumeter
4 examined the quinone-hydroquinone redox couple as a possible alternate to the F e -Fe couple now being used
Modifications to experimental equipment With the exshyception of the tests made with the qrinone-hydroquinone redox couple ail tests made during this pr ied were performed with the equipment previously described5
The equipment consists of the 5 X 7 in Plexiglas conshytactor used in previous work with the water-mercury system The mercury surface in the contactor acts as the cathode in the electrochemical cell The cathode is elecshytrically connected to the rest of the circuit by a Vg-in-diam stainless steel rod electrically insulated from the electrolyte phase by a Teflon sheath The anode of the cell is suspended in the aqueous electrolyte phase and consists of a metallic sheet formed to fit the inner perimeter of the Plexigas cell The current through the cell is inferred from the voltage drop across a 01 -SI plusmn 05 10-W precision resistor The signal produced
14 B A Hannaford (l jl Engineering Development Studies for HollenStll breeder Reactor Processing No 3 ORNL-TM-3l3ltMay 1971) p 30
15 C H Brown Jr Engineerin Development Studies for Mitten-Sit Breeder Reactor Processing So 22 ORNL-IM-4041 tin preparation)
ISO
on a on the
electrode
across the i Hevlen-Fackard xjr plotter The x nbtter bull nrodnoed hy the | the mncmy and a (SCE) suspended in the electrolyte |
to studies nun on the a stow-wcan controned-pocentieJ cyclic woks
patentNttat) was obtained fan the Analytical Chemistry Dtaunu to repfacr the Hewlett-Packard dc poawaapfiy iwtiionely wcd-ThecycJCfohnnrtrTiia three electrode mstrumeut which cortroh lraquo i bttnicn the mercury vnfuir and ai reference electrode whle paahag a cnrrent between the auxamry electrode and the mercury surface Voitafes can be itianrJ between tfVw SCE aad -2 Vw SCE ataacanrateaptol Vnnh The posentiostat can carry a carrot of up to 2 5 A between the auxSnry and mtiiury electrodes
npunninli ahh Ihi tt1 fi ililiai Thr rlrriin ryte used for al the experiments performed daring this report period was nouunaPy OJOOI M Ft2 obtained from ferrous sulfate 0X10025 M Fe obtained from ferric salfate and 0 J M potassium oxalate The oxalate ions form a stable complex with both the re and Fltr2
ftriuuif mnmumnm of the Fe1 reduction cdhccdy
Three anode nMcriab have been tested copper iron ml satisfactory polarization -aaves were pro-
I with al three materials However the copper and iron reacted with the electrolyte solution This addishytional uue reaction caned poor lewudacnwwty in the
I could aho p ornery alter the properties of the To amid tins cnobkrn an anode was fabrishy
cated by poring gold on a 0J062$-m-thka sheet of nickel which was formed to fit the inner perimeter of the electrochemical eel
Shown irgt Fig 8 J is a polarogram measured with the electrolyte described above in the 5 X 7 in Plexiglas contactor mag the gold anode with phase volumes of aboat IJ8 liters each and nc agitation The cell current it plotted as a function of the mercury sarface potential vs the SCE The cnrrent racreasts from zero at zero applied potential to a relatively constant value at an applied potential of about -035 V n SCE In this region contbtvons electrolysis is taking place in the cell corresponding to reduction of FetCiO^ 1 ~ at the mershycury cathode In the region of applied potential from -0J5 V vs SCE to -0JO V vs SCE the cell current
OMM 0W6 79- U429
1 1 1 1 1 1 1 S
2 lt
bull0t-M raquo raquo
m m m f~~ 5 u J I
J ew0^45V
ffl 1 1 1 1 1 0 -OJ -02
Fugt laquo3 Catholic bullohriarmi ware for FlaquoC O)
-0 5 -04 -OS VOLTM0C raquobull SCE
-OS -07 -oa
in Ac 5 X 7 J n m l raquo
151
increases only a smal iniaswt here the current is bullanted by ttugt rate of diffusion of the Fe(CzQlaquogtjgt~ to the mercury surface where this ion is rcdnced The difshyfusion current can be related to the nam transfer coefficient through the electrolyte fifan as prcwontly
The half-waw potential is defined at the potential at which the current is equal to one-half the hunting nine Figure 8 J shows the measured half-waw potential for the ferric oxalate coaapiex The half-wane potential of -0245 V measured in the contactor agrees weD with the wine reported in the literature of -024 V vs SCE for the reduction of ferric oxalate
Under ideal conditions the diffusion current is directly proportional to the polarized electrode surface area and the bulk concentration of the hinting km To detennine that the mercury surface was actually being polarized two tests were perfonned First the anode surface area was decreased by about 48 This had no effect on the magnitude of the diffusion current indishycating that the mercury surface (cathode) was polarized rather than the anode surface In the second test the concentration of the ferric ion was doubled but no concomitant increase in diffusion current was seen Since the diffusion current is directly proportional to the concentration of the limiting km (Fe1) the current should haw doubled The only explanation for this behavior is that the Fe had been reduced by some contaminant in the system possibly present in the mershycury This would have caused ferric ions to be present at only a wry low concentration during ceD operationdue to electrolytic oxidation of the ferrous iron
To ebminate the possibility of reductant being present in the mercury a supply of purified mercury was obshytained from the Analytical Chemistry Division A test was performed using the purified mercury and an elecshytrolyte having the same nominal Fe and Fe concenshytrations given abow Preparation of the electrolyte was completed in the absence of oxygen to preclude posshysible oxidation of Fe to Fe Again the anode surshyface area was decreased with no discernible decrease in the diffusion current indicating that the mercury surshyface was polarized An increase of the Fe concentrashytion from M)25 vnM to Mgt3 mW resulted in an inshycrease in the diffusion current by a factor of 2 indishycating that the waw being measured was the ferric ion reduction waw However the half-wave potential was measured to be -07S V vs SCE which is about three times the reported value
To calculate the aqueous-film mass transfer coeffishycient from poiarographic data the bulk concentration of the oxidized species must be accurately known The
n a n K amp j f a u f l l O u l a m m anuCntSnafsEafannTuB a m m nWanuWOnBTBsnnnnnT- ana^ne-w w ^ m w u^m w ^ p p ewajuajuaawmimaaaBmniw ma mi awnwaawgt^pwnnawBwanpap wa^anu
the electrolyte used in dm second of the two ter^jaen-tkmed abow woe analyzed for F e v asm F by this method Results hnhcatrd that the fie and Fe conshycentrations were 17 and 028 mMrespectiwry which is in poor agreement with the expected values of 030 ajtf Fe and 1J0 mmf Fe2 One poanok cause for the poor agreement is that the Ft 1 was oxidized to Fe during the period when the solution was held in the sample bottles However this was not expected since the dec-trotyta had been sparged with argon to remow dissolved oxygen and the sample botdes were purged with argon toremowair
To aid in oetennming if the reported analytical results were in error due to analytical technique or to method of solution preparation two standard solutions were prepared and sampled for analysis One solution was prepared to contain 56 ugim Fe and the other solushytion was prepared to contain 56 ugnd Fe1 Both solushytions were 1 WmKjCzO^HjO Subsequent analytical results indicated that both solutions had essentialy the same concentrations of Fe3 and Fe 1 50 and 27 fignil respectively Farther investigation wnl be necessary to determine the correct method for preparing andor analyzing iron oxalate solutions
Experiments with the qwmame-bydroonmmae system A possible alternate to the Fe -Fe system for measshyuring electrolyte-phase mass transfer coefficients is the reversible reduction of quinone to hydroquinone at the mercury cathode
The reaction under consideration is
C r l 4 0 + 2 H 4 + 2laquo-CHlaquo(OH) ( I )
Since hydrogen ion as wen as quinone is a reacting material a strong buffer must be present to serve as a supporting electrolyte The buffer causes the H conshycentration to be essentially constant across the inter-facial electrolyte film because the rate at which the buffer equilibrium is established is reiatiwfy rapid comshypared with the quinone diffusion rate1
A quaUtatiw test was made with the quinone system to determine whether acceptable polarization waves couM be measured and to determine whether the quishynone electrolyte is inert to mercury The electrolyte was 001 M hydroquinone and 0005 M quinone with a 0O5 M phosphate buffer at a pH of 70 Satisfactory polari-
16 i M Kolfhoff and 11 Latcanc p 44 inbfaromvp Intencfcnce New Yortt 146
I C A Lin el at Dirruson-Controiled Electrode Reacshytions Ind Eng Ckem 43 2136-43 (1951)
1S2
abon waves were obtained in a small cell with a large copper anode and a mercury pool cathode The electroshylyte was chemically inert to mercury during the tests The color of the quinone electrolyte changed from a light yellow to deep brown within several hours This phenomenon is due to the decomposition of quinone by ultraviolet light Further studies in the S X 7 in contacshytor will be done to determine whether tins system is suitable for mass transfer measurements
8 3 C0NTTNU0USFLU0IUNATOR DEVELOTMENT
R B Lindaucr
Continuous fluorinators arc used at two points in the reference flowsheet for MSBR processing The first of these is the primary fluorinator where 99 of the uranium is removed from the fuel salt prior to the reshymoval of 2 J J P a by reductive extraction The second point is where uranium produced by decay o f 2 Pa is removed from the secondary fluoride salt in the protacshytinium decay tank circuit These fluorinators will be protected from fluorine corrosion by frozen-salt layers formed on the internal surfaces of the fluorinator which are exposed to both fluorine and molten salt To keep frozen materia on the walls while maintaining a molten-salt core in the fluorinator an internal heat source is necessary to support the temperature gradient Heat from decay of the fission products in the salt will be used in the processing plant However to test frozen- JI fluorinators in nonradioactive systems
another internal heat source which is not attacked by fluorine is needed Since electrolytic or autoresistance heating of molten salt has proven to be a feasible means fx providing this heat source studies of auforesbtance ucating of molten salts are continuing A conceptual design was made for a continuous fluorinator experishymental facility (CFEF) to demonstrate fluorination in a vessel protected by a frozen-salt film Design was comshypleted and installation was begun of a fluorine disposal system in Building 7503 which uses a vertical spray tower and a recirculating KOH solution Installation was completed of equipment to demonstrate the effectiveshyness of a frozen-salt film as protection against fluorine corrosion in a molten salt system
8 J I autafetmi and Initial Operation of Aaloteststance Heating Test AHT-4
Equipment for autoresistance heating test AHT-4 was installed in ceil J of Building 4S0S fai this system (Fig 84) molten LiF-BeFj-ThF (72-16-12 mole 7r) is cirshyculated by means of an argon gas lift from a surge tank to a gas-liquid separator from which the salt flows by gravity through the autoresistance electrode through the test vessel and returns from the bottom of the test vessel to the surge tank The test vessel (Fig 85) used in experiment AHT-3 was decontaminated equipped with new cooling coils heaters and thermocouples and reinstalled for experiment AHT-4
The test vessel is made of 6-in sched-40 nickel pipe with a 44-in-)ong (II-m) cooled section from the elecshytrode to below the gas Inlet side arm The cooled secshytion is divided into five separate zones each with two
Oflm 0tJngt 79mdash4W5
bullbullOfF-CAS-
j M M N m laquo$urr|
SCMMTOft
JT~f
i II lraquo li II I I I I
Hi
HEAT FLOWMETER
AUTOMESISTANCC HCATIN6 POWER
SUff lV TEST
VESSEL
ARGON
Fig SA Ftowdwet for autoresifUncc heating test AHT-4
153
Ffc85 AHT-4 lest vewd
154
parallel coils through which an air-water mixture flows The gas outlet section above the salt level has an inshycreased diameter for gas-calt disengagement and is made of 8-io sched-40 pipe The surge tank has a 46-m4ong (I _2-m) 6-in-diam (01 S-m) section to provide submershygence for the gas lift The upper section of the surge tank is 24 in (0-61 m) in diameter and provides suffishycient capacity to contain the salt inventory for the enshytire system The gas-liquid separator is an 8-in-diam (O^Om) conical-bottom vessel with baffles and York mesh in the upper part for gas-liquid disengagement m the heat flowmeter the salt is heated by an internal cartridge heater and the flow rate is calculated from the heat input and ihe temperature iise of the uit stream
The system is started up by heating the equipment and Hnes to 600C (873degK) The argon gas lift is started and initially the salt flow rate is determined by the decrease in surge-tank liquid level After the salt levels in the tank separator and test vessel are constant cooling of the test vessel is started The resistance beshytween the high-voltage electrode and the test vessel walls is checked periodically by applying a low voltage
to the electrode and measuring the current As cooling progresses this resistance wul increase until the point is reached where heat can be produced in the salt at a significant rate (several hundred watts) without cauang a reduction (shorting) of the resistance
The 80-liter salt batch was charged to the surge tank and after minor modifications to the heating system operation was started Four preliminary runs were made lasting from 4 to 12 hr (from the time the gas lift was started until plugging occurred) In the first run plugging apparently occurred in the electrode when the liquid level in the separator fefl too low to provide sufshyficient head for flow to the test vessel
Salt flow in the second run was much smoother and circulation continued for 11 hr without adjustment of the gas lift During this time the test vessel was being cooled and the salt flow rate slowly decreased by V7 from 450 to 425 cnvVmin This was probably caused by an increase in salt viscosity a buildup of frozen salt in the test vessel or a combination of the two The steady salt flow rate and higher salt temperature fgt873 0K and 20-3TK higher than in run No 1) kept the electrode from freezing but the heat supply at the bottom of the test vessel was insufficient to keep the salt outlet from freezing which terminated run 2 The resistance beshytween the high-voltage electrode and the vessel waO increased from 001 to 0X1812 but autoresistance heatshying was not attempted The vertical portion of the test
section had been cooled to 639degK (sobdus temperature 623degK)
Before the third run the output of the powerstat conshytrolling the test vessel bottom heaters was increased by 44 to keep the salt outlet above the freezing point The ran was terminated by salt freezing in the elecshytrode This resulted from too low a salt flow rale (the heat flowmeter was inoperative because of a burned out heater) and too low an initial temperature (723degK vs 823degK in the second run) in the vertical section of the side arm through which the electrode passes
The fourth run was started with some heat on the vertical section of the side arm This section was unshyhealed prenocty As coohng progressed the bottom heaters on the test vessel were inadequate at the salt flow rate being used Increasing the salt flow rate preshyvented freezing at the bottom of the test vessel After 754 hr of operation the liquid levels in the separator and test vessel started to increase indicating salt flow probshylems both at the inlet and exit of the test vessel Alshythough the salt resistance had only increased from OX) I to 003 ft and the average test vessel wall temperature (in the cooled zone) was 658degK autoresistance heating was suited This freed the plug in the electrode allowshying salt flow from the separator to the test vessel and the increased flow raised the test vessel bottom tempershyature and flow resumed from the test vessel However salt flow rates were erratic for the next 2 hrand 9K hr after the start of the run the tert vessel level started to rise indicating a frozen salt restriction in the vessel It was decided to try to transfer the molten salt from the test vessel to the surge tank before complete plugging occurred This was done successfully and 56 liters of salt was transferred to the surge tank After cooling radiographs were taken of the test vessel by the Inspecshytion Engineering Department using a 35-Ci J l r source In the test section of the test vessel radiation penetration was insufficient to permit measurement of the film thickness The bottom of the vessel between the salt outlet and the gas inlet was free of salt as exshypected and the radiograph of flu top of the vessel showed a 25-mm-thick ring of salt above the normal liquid level This is salt deposited on the colder pipe wall by the action of the gas bubbling through the salt Calculations from the volume of salt transferred indishycated an average film thickness of 45 mm (a 65-mm-diam molten core) The salt resistance at the end of the run was 018 ft and the maximum autoresistance heatshying used was 450 W
The main problem seems to be the forming of a unishyform salt film Near the electrode where the hot molten
155
salt enters cooling is much slower than in the vertical section above the gas inlet It is probably in the vertical section where the salt flm becomes too thick and reshystricts the salt flow
8J2 o f Facaty(CFEF)
The purpose of the CFEF is to measure the perforshymance of a continuous fluorinator which has frozea-wali corrosion protection in terms of uranium removal The uranium which is not volatilized but is oxidized to UFs wfll be reduced back to UFlaquo in a hydrogen reducshytion column The facility wul be used to obtain operatshying experience and process data including fluorine utilishyzation reaction rate and flow-fate effects and to demonstrate protection igainst corrosion using a frozen salt Aim
The facility will be installed in a ceD in Buflding 7503 to provide beryllium containment The system wfll conshytain about 8 ft 3 (023 m J ) of MSBR fuel carrier salt (72-I6-I2 mole 3 LiF BeF -ThF4) containing OJS mole ltpound uranium initially The salt wiD be circulated through the system at rates up to 50 of MSBR flow rate (67 X I 0 m 3xc) Because of the short fluorishynator height (1 to 2 m) the amount of uranium volatilshyized will be between pound0 and 95 per pass The variables
of salt flow rate fluorine flow rate and fluorine conshycentration wil be studied by measuring the UFlaquo conshycentration in the fluorinator off-fas stream and by sam-pKrg the salt stream after reduction of UF to UF 4 The fluorinator laquo 4 have two fluorine inlets to provide data for determining the column end effects Reduction of UF 5 war be carried out in a gas lift in which hydroshygen will be used as the driving gu and also as die reduc-tant If additional reduction B required tins can be done in the salt surge tank The surge tank is designed to provide sufficient salt inventory for about 10 hr of fluorination with 95$ uranium volarihntion per pass About 99 of the uranium should have been removed from the salt batch after this period of time
The faculty flowsheet is shown in Fig 86 Salt wil enter the fluorinator through the electrode m a side arm out of the fluorine path The electrode flange wil be insulated from the rest of the fluorinator and the auto-resistance power wiD be connected to a lug on the flange The salt wfll leave at the bottom of the fluorishynator below the fluorine inlet side arm The fluorinator wall wiD be cooled by external air-water cons to form the frozen salt film which wfll serve the dual purpose of preventing nickel corrosion and of providing an electrishycally insulating film for the autorcsistance current Below the fluorine inlet the fluorinator waB will not be cooled and the molten salt wul complete the electrical
TO FLuomnc ftSPOSM STSTU
JVTO-K S S T M C C ~ T M M
TCU f
ifSEMMUl
r-Gf=imdashlaquobullmdash^ni
TOorr-cts
^ - bull I I I T Z
FMCZC VMVC
MPWCTNM COLUMN
CAS-LIFT
HVOMMCR
rO F K M I VMVI
Fit HA Conf immu flaottnalor experimental facility flow Acer
156
OfML DWG 75-15057
FLUOMNE-CONTMHNG U S
TO N 0 T OFF-GAS SYSTEM
Fjs87 Ftmnmt4mfpmtwfmtm
nrcuit to the vessel wall Since all of the uranium will not be volatilized from the salt there will be some UF 5
in the salt at the bottom of the fluorinator The luori-nator bottom exit line and reductio- column will be protected from the highly corrosive UF 5 by gold lining or plating The molten salt containing UF S will enter the bottom of the column where the salt wit be conshytacted with hydrogen The hydrogen will enter through a palladium tube which will result in the formation of atomic hydrogen and greatly increase the reduction rate to UF 4 The hydrogen reduction column will also act as a gas lift to raise the salt to i gas-liquid separator The salt will then flow by gravity to the fluorinator through a salt sampler surge tank heat flowmeter and electrical circuit-breaking pot Off-gas from the separator which contains HF and excess hydrogen will pass through an NaF bed for removal of the HF Uranium ixxafluoride from the fluorinator will also be removed by NaF Mass flowmeters before and after the NaF beds will be used to continuously measure the UFA flow rate
83J Fluorine Disposal System for Building 7503
The CFEF (Sect 832) will be the first test of the frozen-wall fluorinator using fluorine For the disposal of the excess fluorine a vertical scrubber is being inshy
stalled in Building 7503 A flow diagram of the system is shown in Fig 87 The scrubber is a o-in-diam 8-ft-bJgh (015- by 24-m) Mond pipe with three spray nozzles in the upper half of the vessel The surge lank contains 200 gal (09S m) of an aqueous solution conshytaining 15 wt KOH and 5 wt Kl This equipment is designed to be able to dispose of one trailer of fluorine (18 std m 3 ) at a flow rate of 12 scfm (9 X 10 std msec) The KOH solution wil be circulated through the spray nozzles at a total flow rate of 15 gpm (OJOOI msec) The fluorinator off-gas stream will flow cocur-rently with tnis stream The scrubber exit stream passes through a photometric analyzer for monitoring the efficiency of the scrubber
8J4 Frozen-Wafl Corrosion Protection Denomtration
Equipment has been installed for demonstrating that a frozen salt film will protect a nickel vessel against fluoshyrine corrosion ty preventing the NiFj corrosion prodshyuct film from being dissolved in the molten salt A small vessel containing 6 X I 0 1 m 1 of molten LiF-BeFj-ThF4 (72-W 12 mole ) will be used for the demonshystration (Fig 88) The fluorine inlet consists o hree concentric tubes which provide a path for an air coolant
157
FLUOraquoK IN
JL
SALT IXVCL-
OuT
- raquo F L laquo O M OUT
FlaquoSJ Ffi
stream that will be used for freezing a salt film on the outside of the outer tube The wall of the inner lube through which the fluorine will flow is 31 nils (079 mm) thick The inner lube of the fluorine inlet will not be protected from corrosion The vessel wall is also unprotected but is 280 mils (711 mm) thick Fluorine will be passed at a low flow rate (-v830 mmsec) through the salt until failure occurs which is expected in less than 100 hr at the tip of the probe near the gas-liquid-foiid interface Wall thickness measurements before and after the demonstration will show to what extent the salt film afforded protection
A flow diagram for the system is shown in Fig 89 The argon back pressure will be recorded to provide an ndication of corrosive failure Failure of the tube below
the salt film will allow some salt to leak into the argon cooling annulus The salt will be entrained up into the cool portion of annular space causing a restriction to
the argon flow The system waf be designed such that the fluorine flow is terminated automaticaly when either a low argon pressure is detected in the anrndus or when a high argon back pressure occurs
84 FUiaiWCONSnTUnON ENCINEEJUNC OEVELOTMENT
llMCounce
The reference flowsheet for processing the fuel salt from an MSBR is based upon removal of uranium by fluorinatioa to UFraquo as the first processing step 1 The uranium removed in this step must subsequently braquo reshyturned to the fuel carrier sal before i u return to the reactor The method for recombiniag the uranium with the fuel carrier salt (reconstituting the fuel salt) consists in absorbing gaseous UFraquo into a recycled fuel salt stream containing dissolved U F 4 affording to the reacshytion
UF f c(g)UF4ld) = 2UF(draquo laquo2raquo
The resultant UF S would be reduced to U F 4 with hydrogen in a separate vessel according to the reaction
U F ltdgt bull H (ggt = UFlaquo(d) bull HF(ggt (31
Engineering studies of the fuel reconstitution step are being started to provide the technology necessary for
the design of larger equipment for recomputing UFraquo generated in fluorinators in the processing plant with the processed fuel carrier salt returning to the reactor During this report period equipment previously deshyscribed was fabricated and has been installed in the high-bay area of Building 7503 This report describes instrumentation for off-gas analysis including a prelimishynary calibration curve and two alternatives for proshyviding corrosion-resistani gold linings for equipment to be installed later
The nickel reaction vessels presently installed will be used to test the salt metering devices and gas supply systems After the initial shakedown work is completed the UFraquo absorption vessel Hj reduction column flowing-stream samplers and associated transfer lines will be replaced with gold or gold-lined equipment Gold is being used because of i u resistance to corrosion by UFraquo gas and U F dissolve in the salt
1972 18 Chem Technol Dh Anim frogr Kept Mar SI ORNL-4794p I
19 R M (ounce Engineering Development Studies for MolenStll Breeder Reactor Processing So 19 ORNL-TM-4863 (July 1975) pp 38 42
158
OMN M 6 rS-OTM
FCV-3 nOccWM HASTMGS MASS FLOWMETER
ACTIVATED ALUMNA TRAP
Ffeft9 FfocM ait BtotaciiMi
841 for Analyzing Vest Off-Goes
The equipment for the second phase of the experishyment will consist of a feed tank a UF absorption vesshysel an Hj reduction column flowing-stream samplers a receivei tank NaF traps for collecting excess UF and for disposing of HF gas supplies for argon hydrogen nitrogen and UFraquo and means for analyzing the gas streams from the reaction vessels (Fig 810) The equipshyment wul be operated by pressurizing the feed tank with argon in order to displace salt from the feed tank to the UFlaquo absorption vessel From the UFlaquo absorption vessel the salt flows by gravity through a flowing-stream sampler into the H2 reduction column From the Hj reduction column the salt flows by gravity through a flowing-stream sampler to the receiver tank Absorption of gaseous UF t by reaction with dissolved UF 4 wiD occur in the IFF absorption vessel and the resultant UF5 will be reduced by hydrogen in the Hi reduction column The effluent salt is collected in the receiver tank for return to the feed tank at the end of the run
The off-gas from the absorption vessel and the reducshytion column will be analyzed for UF and for HF reshyspectively
The respective off-gas streams will be continuously analyzed with the use of the Cow-Mac gas density balance A sample stream is taken from the main off-gas stream and passed through the balance for analysis (Fig 811) These analyses wiO be used in determining the efficiencies of UF absorption and H 2 utilization
The efficiency of UF absorption will be determined by metering UF and Ax to the UF reaction vessel and determining the UF content in the vessel off-gas using a model 11-373 Cow-Mac gas density cell2 The H utilization will be determined similarly Hydrogen will be metered to the H 2 reduction column and the column off-gas wD be anayzed for Hj content also using a model 11-373 Cow-Mac gas density ceD The Cow-Mac cell commonly used as a gas chromatograph
20 Gow-Mac Instrument Company 100 King Road Madison New Jersey
159
bullWLDIN6
bull SYSTEM
Flaquo SIO Ftow lt ^ w o gt n ^ w i l M
msw NEACnON VflaquoSCL
P9E Y
f OWL DUG 7VS909
0FF-6AS
j r _^DT
KOC
ROTCTER|V] $
Ffc 811 SdMMMtic M of fMl ncomtitalfcM experiment off-gn
160
detector provides a continuous signal which varies directly with the density of the sample gas allowing continuous analysis of the sample gas stream with accushyracies of 3 to 4ft Because the detector elements are not exposed to the sample stream the gas density cell is useful in analyzing corrosive gas mixtures
Nitrogen and argon will be reference gases for the gas density cells used for analyzing the off-gas from the UF absorption vessel and the H reduction column respectively The response of the gas density cell is fairly insensitive to changes in the sample gas flow rate when nitrogen or argon is used as a reference gas2 z To measure varying Ar-UF and H2-HF ratios with the gas density detectors it is necessary to control the refershyence gas flow rate precisely However Irigh precision is not required for controlling the sampie g^ flow rate The reference gas flow rates are controlled sufficiently by rotameter and separate gas supply systems A satisshyfactory means for providing reproducible sample flow rates has been developed The sample stream is taken from the main off-gas stream (Fig 811) and flows through a capillary tube the gas densiiy detector an NaF trap to remove the corrosive constituent (UF or HF) and a bubbler to provide a constant downstream pressure The pressure upstream from the capillary is maintained at a higher constant value by means of a similar bubbler in the off-gas line downstream from the NaF trap The NaF traps provide sufficient volume in the lines so that small pressure fluctuations from bubshybles in the process vessels and in the bubblers are effecshytively damped out The flow rate is not constant (although it is reproducible) because as the concentrashytion of the sample gas changes its viscosity changes producing changes in sample flow rate under the prevailshying conditions These flow rate changes superimposed upon concentration changes in the sample stream to the gas density detector result in a nonlinear response of the gas density detector to changes in concentration The effects are reproducible however and a reproducible calibration can be obtained Such a calibration was obtained with mixtures of hydrogen and nitrogen (Fig 812)
For sample gases containing hydrogen and at refershyence gas flow rates below a certain critical flow rate hydrogen will diffuse countercurrently into the refershyence gas stream to the area of the detector elements
21 J T Wjfoh and D M Roue tor Oiromalofr US) 232 40 17)
22 C L Ouillemm and M K Auricourf (its Chromalogr I 24 29 (October 1963)
onw MG re-mo
i i i 1 bull mdash I I I I i DO 90 0
2
Ffc 812 Cafeoraam i laquo of Gow-Mac gas Oettmtf ccM MOM in fad iccoasMatioa t^mtimj claquojlaquoipmlaquoi for H ami N-
Due to the high thermal conductivity vf H the back diffusion of H can greatly affect the sensitivity of the gas density cell However if sufficiently high reference flow rates are maintained this problem can be overshycome
842 Design of the Second Fuel Reconftitutkm EjtgMecimg Experiment
The design of equipmeni for the second fuel reconsti-lution engineering experiment (FREE-2) is continuing The equipmeni for FREE-2 will be similar in design to the equipment for experiment FREE-I except for the addition of an intermediate liquid-phase sample port beshytween the UFraquo absorption vessel and the H 2 reduction column (Fig 810) In addition all vessels and transfer lines exposed to dissolved UF 5 with the possible excepshytion of the receiver lank will be gold or gold lined Gold sheet 0010 if (02S mm) thick is on hand for the fabricated liner of the UF absorption vessel Two altershynative exist for lining the H 2 reduction column and the receiver vessel interior gold plating or a fabricated gold liner
The minimum plating thickness that would probably provide a pinhole-free liniig is approximately 0005 in (013 mm) The minimum thickness for a fabricated gold liner in vessels of this size is approximately 0010
161
in (025 mm) Fabricated gold liners are economically competitive with gold plating in the thicknesses menshytioned because gold sheet is available at ERDA prccious-mctal account prices approximately S3499troy oz (SII3g) and gold in commercial gold-plating solutions is available only at market prices of about Sl64troy oz (S5J7g) as of June 18 1975 Some comparisons important in the choice between interior gold plating or fabrication of a gold liner are
1 the technology involved in fabricating a welded gold vessel is available while some technology would need to be developed for interior plating of vessels having a high lengthdiameter ratio such as the H2
reduction column 2 the time involved in both approaches is approxishy
mately the same 3 the plating will be difficult to inspect and there will
be no guarantee of pinhok-free coverage while dye penetrant examination of welded joints is available for a fabricated liner
Because it is unclear whether there is sufficient gold in the ERDA precious-metals account for lining the reshyceive tank liner gold plating is favored There is the ziditional alternative bullbull not lining the receiver tank since i orrosion of the receiver vessel by UF5 in the salt could ie tolerated and corrosion products could be reshymoved by hydrogen reduction and filtration between runs
85 CONCEPTUAL DESIGN OF A MOLTEN-SALT BREEDER REACTOR FUEL PROCESSING
ENGINEERING CENTER
D I Gray J R Hightower Jr
A conceptual design is being prepared to define the scope estimated final design and construction costs method of accomplishment and schedules for a proshyposed MSBR Fuel Processing Engineering Center (FPEC) The proposed building will provide space for the preparation and purification of fluoride sail mixshytures required by the Molten-Salt Reactor Programfor intermediate- and large-scale engineering experiments associated with the development of components reshyquired for the continuous processing capability for an MSBR and for laboratories maintenance work areas and offices for the research and development personnel assigned to the FPEC
bullORNI Knpneeriti Division
The project wSI consist of a nev three-story engineershying development center approximately 156 ft (475 m) wide by 172 ft (524 m) long The building will have a gross floor area and volume of 54300 ft 2 (5100 m x ) and 1218J0O0 ft J (34300 m J ) respectively and vhB be constructed of reinforced concrete structural sled concrete Mock masonry and insulated metal paneling The building will be sealed and will be operated at negashytive pressures of up to 0 J in of HjO (75 Pa) to provide containment of toxic materials The FPEC wit be located in the 7900 area approximately 300 ft (91 m) west-southwest of the High Flux Isotope Reactor The engineering center will contain
1 Seven multipurpose laboratories buu on a 24 X 24 ft (7 J X 7 3 m) module for laboratory-scale experishyments requiring glove boxes and walk-in hoods
2 A high-bay area 84 X 126 ft (256 X 384 m) equipped with a 10-ton (9000-kg) crane for large-scale development of processes and equipment for fuel processing at the pilot-plant level
3 A facility for preparing and purifying 16000 kg per ye-r of fluoride salt mixtures needed for the Molten-Salt Reactor Program
4 Support facilities including counting room process control rooms change rooms lunch and conference room and data processing room
5 Fabrication and repair shop decontamination room and clean storage areas
6 A truck air lock to prevent excessive ingress of outshyside air during movement of large equipment items into and out of the high-bay area
7 Two 5-ton (4500-kg) service elevators one inside the building to service the regulated areas and one outshyside to service the clean areas and to move filters to filter housings on the third floor and roof
8 General service and building auxiliaries including special gas distribution systems liquid and solid waste collection and disposal and filtered air-handling and off-gas scrubbing facilities
The experimental program planned for the building involves large engineering experiments that use 2 1 U 2 T h Be hazardous gases i F a H 2 and HF) molten bismuth and various fluoride and chloride salts Inishytially radioactivity will be limited to that necessary for low-level beta-gamma tracer experiments The laborashytory area can later be upgraded if desired for use with alpha-emitting materials at levels up to I kg of n P u
The laboratory area will consist of seven 24 X 24 ft (73 X 73 m) modular-type laboratories and a general-purpose room Bench-scale experiments of the type now performed in buildings 4505 3592 and 3541 will be
162
carried out m these laboratories FtoMems encountered in the large-scale experiments can be studied via smaE subsystems Inert-atmosphere glove boxes wil provide space for examination of samples removed from both the large and the small experiments The laboratory area wul be maintained at a negative pressure of 0 J m of H 2 0(75Pa)
The high-bay area wul be the main experimental area where large engineering experiments wifl be performed Experiments wnl involve circulating mohen mixtures of LiF-neFj-ThF4 lithium chloride and molten Bi-Li alloys The experiments wffl also use elemental fluorine hydrogen fluoride hydrogen chloride and hydrogen gases as reactants and wnl use purified argon for purgshying Excess fluorine hydrogen fluoride and hydrogen chloride wil be neutralized in a caustic scrubber using KOH solutions and the cleaned and filtered off-gas win be ducted to a bunding exhaust system The experishymental equipment and components wil be housed in steel cubicles with floor pans which can contain any salt spJO The cumdes wnl be maintained at a negative presshysure with respect to the high-bay ambient The high-bay area can be supplied with up to 45000 cfm (212 msec) of air The air can be from recirculated inside
air laquo fresh ak from the outside The high-bay exhaust system wil be designed for 30jOOOcfm ( I 4 J msec)at floor level and 50000 cfn (236 msec) at the roof framing level A l exhaust ducts wnl contain fire barriers upstream from the double HEP A filter banks
The salt preparation and purification area wil consist of a 25-ft-wide by 3S-ft4ong by 14-ft-hJgh (76 X 107 X 4J m) raw materials storage room a 22 X 22 X 28-ft-high (67 X 67 X 8J m) room for weighing and blending the salt constituents and a 40-ft-wide by 45-ft-loug by 28-ft-high (122 X 137 X 85 m) room for melting rk-HF treating and filtering the fluoride salt mixtures This facility should be capable of producing I6j000 kg per year of fluoride salt mixtures using the batch processing method in use at the (acuity at Y-12
The estimated cost for the FPEC is SI 5000000 of which $5200000 provides for inflation during the three years required for design and construction of the baking
The design is essentially complete and the conceptual design report is scheduled to be issued in September 1975 Authorization for this project will be proposed for FY 1978
Part 5 Salt Production
9- Production of Fluoride Sak Mixtures I
F L Daley
A salt production facility is operated by the Fluoride Salt Production Group for preparation of salt mixtures required by experimenters in the MSR Program The group is responsible for blending purifying and packshyaging salt of the required compositions
Much of the salt produced is used in studies on Hast el -loy N development in which the concentrations of metal fluorides particularly nickelironand chromium are important study parameters Ic is thus desirable to use salt in which the concentrations of these metal fluorides are low and also reproducible from one salt batch to the next Oxides are undesirable salt contamishynants primarily because of the adverse effect of uranium precipitation and also because of the effect of oxides on corrosion behavior of the salt Sulfur is another conshytaminant present in the raw materials used for preparing salt mixtures Sulfur is quite destructive to nickel-based alloys at temperatures above 350degC because a nckel -nickel sulfide eutectic which melts at about 645degC penetrates the grain boundaries and leads tc inlergrlaquonu-lar attack of the metal The maximum desired ievels for these contaminants in the fluoride salt mixtures are iron 50 ppm chromium 25 ppm nickel 20 ppmsulshyfur lt5 ppm oxygen lt30 ppm Other duties of the group include procurement of raw materials construcshytion and installation of processing equipment and reshyfinement of process operating methods based on results from operation of the production facility
When the facility was reactivated during 1974 initial production was carried out in existing small-scale (8-in-
bullConMiliam
r MSR Program Research and Development
RWttorton
diam) reactors while new large-scale (I2-in-diam) reacshytors were eing installed Experience with both the small and laige units is summarized in the remainder of this chapter
91 QUANTITIES OF SALT PRODUCED
The 3-in-diam reactor was used for production from startup of the program in early 1974 through the first three months of 1975 During this period a total of nine full-scale batches (315 kg total) were processed and made available to investigators Salt from the nine batches was shipped in a total of 2i containers of apshypropriate sizes In general operation of the 8-in-diam reactor proceeded smoothly and the resulting salt was of acceptable composition and purity
Production in the 12-in-diam reactor was started in March 1975 Five production runs each involving about 150 kg of salt have been carried out Of the five salt batches processed four were suitable for use most of the salt from these four runs was used for fuel procshyessing experiments In contrast to the earlier runs in the 8-in -diam reactor difficulty has been observed in the 12-in-diam reactor with corrosion of dip lines in the meltdown vessel and with increasing concentrations of metallic impurities in the product salt
92 OPERATING EXPERIENCE IN l2-in-diani REACTOR
Operating data from the five production runs in the 12-in reactor are summarized in Table 91 Analyses of the resulting salt batches are given in Table 92 A description of the processing operations and conditions
164
TaMe9l ttoccMag fab derived fto to rave taae ami titntioa of iafci aad oatlet flows
Batch number (FS-)
Batch size
ltkgt
Total tarn Ihr)
HF in
(moles) in
(motes)
HF out
(molest
HF reacted (moles)
Dariag hydmlhoriaatiMi 101 150 125 1953 4253 1712 241 102 150 1025 2331 2738 2331 0 103 150 975 1808 2603 1419 389 104 150 95 2853 2473 2434 399 105 12 140 3752 2857 1877 1876
Batch number |FS-)
Batch size
Total time
Total H in
Total HF out
HF in otT-jraquos Imeq per liter of H) Batch
number |FS-) Ike) (hr) (moles) (moles) Start Finish
Daring hydrogen ledacliua
101 150 176 4725 0026 00018 00064 102 150 186 4995 0595 0100 0O50 103 150 244 6520 1560 0625 0016 104 150 440 12040 2180 0746 0008 105 112 320 8514 3290 0476 0102
Table 92 Aaatyxsof 1501 batches of LiF-BeF -ThF4 (72-16-12 mole )
prodaced in die 12-araquo learior
Batch number (FS-)
Analyses Batch
number (FS-) Li r)
Be Th F rlt)
Fe (ppni)
Cr (ppml
Ni (ppml
S (ppnw
O (ppm)
Nominal 72-1612 790 228 4411 4571
101 795 252 4392 4620 82 24 17 737 lt25 102 8 64 222 4200 4600 75 30 600 80 360 103 811 231 4327 4574 60 25 8 25 350 104 839 200 4381 4532 85 65 10 91 NO 105 1046 290 3435 5125 82r 25 8 576
prevailing during hydrofluorination and hydrogen reduction is given in the remainder of this section
921 Charging and Metting of Raw Materials
The salt produced in the l2-laquoi-diam reactor has been of the MSBR fuel carrier salt compostion (72-16-12 mcle LiF-BeFj-ThF4) production of salt of this composition will continue except that some batches will also contain 03 mole UF 4 If the production schedule permits an inventory of non-uranium-bearing salt will be accumulated before beginning the producshytion of uranium-bearing salt The LiF raw material for
the salt production facility is supplied by Y-12 as needed the BeF2 and ThF 4 are taken from raw mateshyrials that have been on hand for several years The only apparent effect of the long storage time on the raw materials is an increased moisture content of the BeF2
The production unit includes two l2-in-diam 72-in-high type 304 stainless steel vessels each of which is (Wed internally with a full-length open-top copper cylinder in which the salt is contained One vessel is used for batch melting of the raw material) which are charged to the meltdown vessel by gravity transfer through a 2-in-diam pipe the pipe extends into a weighing and charging room and is closed by a sealing
165
flange except during the loading operation The second unit the processing vessel is identical to the meltdown vessel except for the charging line Both vessels are fitted with dip lines for introducing gas to the bottom of the vessels for mixing or purifying a salt batch and both are connected to an off-gas system Each vessel is supported in a stainless steel liner and while in use is located in a heavy-duty electrical furnace The receiver vessel to which the salt product is transferred is 12 in in diameter 36 in high and is supported similarly in a furnace adjacent to the processing vessel furnace Salt transfer lines from the meltdown vessel to the procshyessing vessel and from the processing vessel to the reshyceiver are autoresistance heated via a 24-V power supply
The operational sequence includes salt charging meltshying and mixing in the meltdown vessel and transfer of the resulting salt to the processing vessel for purificashytion The process steps include hydrofluorirution hydrogen reduction and filtration during transfer of the purified salt from the processing vessel to the receiver vessel During both the hydrofluorination and hydrogen reduction steps the receiver and processing vessels are maintained at the same temperature and the process gases are passed through the receiver before being fed to the processing vessel in order to eliminate any oxide film on the interior of the receiver
The raw materials are loaded into the meltdown vessel by technicians wearing air suits having a supply of cooled fresh air The work is carried out in a small enclosed room in which containment is maintained by positive flow of air through the room to a bank of absolute filters The appropriate quantities of each of the raw materials are weighed and charged through a loading chute directly into the l2-in-diam melidown vessel which is at room temperature The larger lumps of BeF 2 and occasional lumps of LiF are broken by hand to facilitate loading and to provide improved mixshy
ing The ThF 4 is a fine powder which does not require six reduction The charging method leaves much to be desired melting would be more rapid and more predictshyable i f the particle size of the raw materials could be reduced and all components mixed well before they are charged to the meltdown vessel
Some of the more important impurities in the raw materials are listed in Table 9 3 The values shown are average values in most cases The metallic impurities are satisfactorily low however sulfur and possible silicon contribute to corrosion problems during melting of the raw matercls The moisture content of the raw mateshyrials is not shown but is an important parameter It is believed that hydrolysis of the fluorides during the initial heating period generates hydrofluoric add which subsequently reacts with sulfur- and silicon-containing compounds in the raw materials to form hydrogen sulshyfide and fluoroalidc add The quantities of these mateshyrials produced appear to be dependent on the temperashyture at which the meltdown vessel is held during the initial portion of the melting operation with 2 S proshyduction being most noticeable at temperatures above S00degC An addic compound which contains silicon and fluorine is evolved freely at lower temperatures in the 125 to 500degC range however the extent to which the material is corrosive to the meltdown vessel is not known Analytical data necessary to determine whether these low-temperature gases contain sulfur-bearing comshypounds are not available
The major effect of hydrogen sulfide on nickel comshyponents at temperatures in the rage 600 to 700degC is rapid eirbtlement of the nickel This action has resulted in breakage of dip legs in the meltdown vessel at the rate of one dip leg per run Breakage v observed to occur in the gas space above the melt and the broken dip leg falls to the bottom of the meltdown vessel where it is available for further attack by corrosive material) dissolved in the salt After melting batch
TaMe 93 Impr i t in tm raw material mtei ia ftmoriit a l t production (ppm)
Component S Si Fe Cr
Component Av Max A Max Av Max AVK Max
L i l 21 44 100 IllO 20 25 lt l lt l BeF 300 500 IHO I0O 50 100 20 40 rl ir- lt M 0 ltIO0 lt IO ltin 25 62 I I 17 Mixed raw
material^ ino 131 47 47 26 56 9 15
Mix ture required to produce tali havirfi compofll ion of 72-16-12 mole i I i l - B e l - I h i -
166
FS-101 was passed through a nickel filter having a mean pore size c f 40 i but plugging of the filter on subshysequent transfers led to its removal from the system Transfers from the meltdown vessel are now made after allowing a period for particulate material to settle
A stainless steel dip leg was used in the meltdown vessel during the melting of batch FS-105 in an attempt to avoid cracking of the dip leg The use of stairJlaquolaquo steel was liter concluded to be unsuitable because of the increased concentrations of iron and chromium observed in the resulting salt product The dip leg did not embrittle nor break during melting of the salt but extensive corrosion was noted on the submerged porshytion of the leg As a result of these observations a dip leg of copper and nickel was constructed by placing a copper sheath over a heavy-waD nickel tube The nickel tube provides rigidity and the copper is used both outshyside and inside of the nickel tube to obtain resistance to corrosion The copper sheaths are welded together at the lower end of the dip leg located in the meltdown vessel This combination of materials is expected to result in an increased dip leg life and less contamination of the product salt
An error was made in charging the ThF4 for batch FS-105 which resulted in salt that did not have the desired composition
922 Hydrofluorination and Hydrogen Redaction
After a salt batch has been melted in the meltdown vessel it is transferred at a temperature of about 750degC to the processing vessel where it is sparged with an HF-Hj mixture at a temperature of about 625degC for a period of about 10 hr The salt is then sparged with H 2
at 700degC the H 2 flow rate of 10 std litersmin used during the hydrofluorination step is continued for 30 lltr to reduce iron and nickel fluorides to their raquoraquopective metals
Progress of the hydrofluorination step is monitored by determining the HF content of the HF-Hj inlet and exit gas streams by absorption and titration of the HF in a metered volume of exit gas When the HF concenshytration of the inlet and exit streams becomes equal (or the concentration in the exit stream becomes slightly higher than that in the inlet stream) contact of the salt with the HF-Hj mixture is stopped A relatively low temperature about I00degC above the salt liquidiu temshyperature is used to minimize the rate of corrosion of equipment and to maximize the rate at which oxides are hydrofluorinated The hydrofluorination step is folshylowed by treatment of the salt with hydrogen at 700degC
to reduce iron and nickel fluorides The utilization of hydrogen during this step is low and large volumes of H are required Since the reduction reaction releases HF the concentration of HF in the off-gas stream is monitored and hydrogen treatment is stopped when the HF concentration reaches a low value (about 002 meqliter) and remains constant within the detection limits of the titration method
The total gas flows (H 2 and HF)during the processing operations are shown in Table 91 The values in the table reflect a steadily increasing quantity (from FS-101 to FS-105) of HF generated by H2 reduction of metallic fluorides that can be ascribed to a buildup of metals (largely iron and mcke) in the salt heels in the meltshydown vessel and in the processing vessel during operashytion These metals are converted to fluorides during hydrofluorination and thus add to the total quantity of metal fluoride to be reduced during hydrogen treatshyment
9 3 SUMMARY
The information presented in the previous sections indicates that the following factors are important in producing high-quality salt
1 Analyses of the raw materials indicate that there will be no concern with metallic contaminants unless metallic corrosion products are introduced during the salt purification or melting steps
2 The sequential buildup of metallic impurities in the salt produced in the I2-in-diam facility is the result of corrosion of the equipment This corrosion can be minimized by use of copper whenever possible when equipment is simultaneously exposed to salt and process gases Periodic hydrofluorination and discard of flush salt in the processing vessel should control any minor buildup of corrosion products
3 Although not demonstrated by data shown in this chapter it is believed that oxygen contamination can be held at low levels by maximizing the removal of moisture from the raw materials before they are melted and by improving control of the hydroshyfluorination process A method for measuring the H 0 produced by reaction of HF with oxides in the starting materials is being tested This should aid in determining the proper time at which to terminate contact of the salt with the HF-H2 mixture Alsoit may be necessary to determine the sulfur content of the off-gas since this may be the most difficult conshytaminant to remove from the salt
MOLTEN MLT REACTOR PROGRAM AUGUST lraquo4
i I MtfttitSI HHMHAM OIHH UgtM
m D M K M AMD M V I LOMMlaquo1 i n iH tGlL H
svsriMi AO AKAIVHI J N I N C U H
1 j A L L I N H
H 1 K | N lt I N
0 1 M A S M
0 I M I D N
ftWIMt A N C O f t M O M H T l M V I L O M N N I
m M G u laquo laquo O N H
A A H U - t U t l 1 M
W 0 H l V l M f t M N M 4 ft M l i l M H
m bull raquo | N S O N H 1 ftlOOLl N O t I R A V H I N M M bull H O raquo l raquo raquo S O N n
bull F A I M M O N M I M
4 M L V l l C L C M l M i S H V D i V t S i O N C M l W l t t N T D V I K O A j C M l W C A k F I C M A J O L O C J V 0 V gt V O V lt TACS A N D C A A W C S lgt iV traquo iC i M A C T O M ) O i V i S lt O N I X m v l f t S l T V O I I I N N t M I l
A t A H H I A U
M 1 M C O V MAC
M J U H U 0 Y N 1 T U W I I
H 1 I f c C O l MAC D N bull M lt S gt i MAC 1 M K h l S I A D MAC A k C L A J J I N C MAC I I J C X O U t t MAC
1 A U S T M A N G MAC
H l H I I I T A N t l MAC C A H V M A N M J laquo K t i t t H MAC
bull C U S U I MAC
bull M r N A M MAC 1 K R U C M I MAC A C t C M A f raquo M A U S ( H MAC i ft W O O t i S MAC
C M 4 M I C A L M K K I U 1 I M M A 1 I A I A L I
H M U I W V MAC
I I C H N I C A I t U W O I I t
A V HOI I M i MAC C 1 0 o N MAC n M raquo 4 H M t M - MAC 1 C k l l T N t H MAC J t I M i l H I H MAC I M l A r M l H L V MAC
J 1M H I N D I I C K S MAC T t M I N S O N MAC J 0 M ICWON - MAC
1 1 l A M H I X i 1 MAC
1 bullbull I I I MAC A ilaquo M i l l k H MAC (1 A gt 0 1 T1H MAC
I d H A H D O h MAC H H V I A M N O k MAC 1 i X M I M S K V H
tt I I S 1 I N I S MAC C K l i K l M A S MAC 1 H r H D I I I M MAC C A W A l l laquo ( l n 1 1 M K I C I H O I I S I MAC
M M gt H O C I t t l a O I V l l O r W I N I
J H Mt r HT ( )WraquoM IH bull
C M I M I C A l 0 I V I L 0 A M I N 1
A O fttk M l M S M H I I N M M
l O l N l l f t l laquo a O I V l l O H H N 1
gt H H I U H f O W I H JH C M SHOWN m n M c o i m c i c w t i bull H bull U N O A U l H M C S V A lt i
I B I A M S H O P A Y M
M M H C H I M I I T M V
l M M H H i S i A 1) r l L M I H S c L M A V A ( H t M t I C c raquo C A N T O N c I M l M c t O d i LPS T H I C K c raquo A r o i i raquo bull t H N M H O N k l U N t
D 1 H l A T H f R i V 1 O V A L l N l l N I c
A N A L Y T I C A L C H I M l t T N V
M M A A C H A f t O O I V I t O M M I N V
A I M f V I N AC H t A M | t bull AC B H C l A M K AC J M M A L I AC p L M A N N I N l t AC J P T f l U N t t AC
A N A l V S f l
i i I I M raquo I M At t it O o r t M - A l
ft ri i A i N t AC J A C A H I t l f AC
C O N S U L T A N T
r M A M A H t O V I I I
_ -L_ ULTMOOUCTION N M HtWIQN c bull I U A l t v C
bullH i AHVAK C I A c XJHNtOkt C t
1 I bull i
BLANK PAGE f4
bull f
Printed in the United States of America AnaiMMc from National Technical Inforniotion Service
US Deportment of Commerce 5286 Port Royal Road S o r - ^ Virynia 22161
Price Printed Copy SampSOMicrofche $225
I M V taporf laquopaw pranwas at an aocpaar a a w ajaaaaran a 001 latajaa aanai
Ada^unr0oon nor aft of ^bullJw onolovaaa tiar ooy of tfJaw connractors aabxonaaciors or insa anaaloapnv faonas an oaavrantv noorav o nooaoaV or
WBaransaaa fatrade bull P ^^raquo^aoo(r ajaww Rwgtgtraquo bullbullbull WMPCI a pr PEaa RK^PJWgt ar ranrfraquofmwww ttrnt I B uaf ajovaj not awKfaja prrtnjajh oamotf rtojm
U C 7 raquo -
CoMfKlMo
RMKMOO MMucrsiifii
LE
FENUAftY 1976
OAK RIDGE NATIONAL LABORATORY Oak R 4 T O T M H W 37W0
opwaNdby UNION CARMX CORPORATION
forffw ENERGY RESEARCH AND DEVELOPMENT ADMINISTRATION
MASTER V
~r -ruic rvVUMENT IS UNLIMITED WSTWBUTION OF THIS DucUWttrade ^
1 M Mpoct raquo olaquoc laquorf x laquornrraquo v4 IMA MIMA Weuro M C I MIO
i t a k trpoffe iHji AcwriM tnr ptoyrc bullgt the (aopun Ilihrgt c^wt i==v agt
0 laquo M 4 4 K M bMg 1 M V gt 31 Ilaquoraquo O K M - raquo tow (aMj CViltn 31 W ( K M X U total E M M J laquorgt 31 I OlaquoM raquo tow IKM laquolt gt-iraquo 0laquoM7raquo tonJtJMMfMgt3lllaquo5laquo ORMOSlaquo tnaikmtmtOctlt+tt HI (MSI m D m (tthnj teraquogt 3I JMI ii 30 |ltlaquo0 OKM-3QI4 tomJ fattMf Mgt 31 IlaquoMO ( K M 31 towi fawMf Frmgt gt Iltl OHM 321 lt towrftJMMf AMMM3I Ilaquoraquo OmSLi^Z total FMIMJ Hbrmay gt bull- ORM-334 tomt tJnf AMWlaquo 31Ilaquo ORM-34P to MOM Jmraquogt 311laquob3 0laquoL-35gt totaj tMJwf JMgt 31 IMJJ ORM-3raquogt towl EMM tani 31 fM O t M r rrd M Mgt 311laquoM OHM-3 I towJ to FVfrfwry 3gt bullbulllt OKM-sraquo total EMM laquo laquo i 31 Iltraquolt ORM-gt3b totaJ EMM F4MMgt gt IlaquoraquoM ORM-K~ to vlaquo MAM M J1Ilaquoferaquo G4LM4I J tow EMM i n laquo gt raquo I W OHM-raquobullraquo ftnud EarfMf Ailaquow4 3 bullraquo aM-raquolaquo4 toraquoi E M FlttNlaquoHgt i OHM4344 total EMJH Ktfmt 31 IltM OftM-ll towi EMJM FfMfgt gt Ilaquoraquoyenraquo ORM444 totaJEiMJ3llltraquo OfcM 444ft toml Eraquofc F4WlaquoM gt I OftM4j total b u b tmgmt 31 laquobull OftM467 feftal EMJM Flaquofcrmv bullraquo Ilaquo7l 0RM4gt total E n 31 I7| OftM47iC torn EMM Flaquoflaquoy -^ llaquoraquo OXM4K3 total EMM AapM 31 17 OftNL-5011 total EMM AMlt 31 I4 ORM-ttM towl E n FlaquoraMgt gt W
Coimnti
SUMAftY
PARTI mm KUCM Aim vcvujonmsj t v^SItMS AND ANALYSIS 2
raquo l n t t raquo bull ( bull bull laquo a Mete SJpound nam I I M 5 M C J U I M raquo 2 1 I r laquo 4 w t Srfl TlaquodMc4ap FMhn 3
I 2 amp w Rftowr raquo laquo sect bull 1 3 mroMi Aaalyws - 9
131 MSMSnrgt 9 l raquo TXr tCraquoo 12
14 t t^TcnpctsnMrDNpi I te fe 12
2 s m t J t S A X P C O I 0 9 ^ T S 0 m U gt r M L T 16 21 l t -Sgtnn TfdMofofy Fac 16
211 Crwraquomwiw4$rfihmdashySgttnOfcltjtiraquowi 16 2 12 S-ftowraquo^vfuiwHWif DWraquo3MCJamiilaquoirfVjnjWrnuwteimcraquogtn IS M M N ^ F laquo W M I F W 19 214 P w i mtmmiH 22
2 2 Claquo4aM-Sak T laquo f c raquo w F n iCSTFl 22 22 1 UvOMYJCM 22 2 2 M M M T M 23 223 TIMM Ei^tiMm 24
23 Ftwcrtf rlaquonlaquocimi Lon^sect 2 23 1 0prraquoiMigtfMSR-FCl-2raquo 26 231 DtwptmiCamnKnmafKVymtifCL 2
PART 2 IMLMSIRV
3 FUEL SALT CHEMISTRY 29 31 C n y i i i mttkt Lirtitmdashi Trfcinw Syami 29
3 Sprctrawoyy of Tcnprtan Sptctn n Manni Swu 30
3 3 Thr UrjMHMi TrirjIWori - H y d w y Ci|iiraquonmdashi m Matio Fhwnic SahMww 31
34 Fwam EJrctra S w laquo n laquo Mate Salts 32
35 Flaquo4 SafcladMi Sad lmnmttm Snafcn 34
36 Laiiior mamp FOWMHUH LJuMptcs of Fw-Ro TraMOc Meld Fbariafcs 37
ii i
IV
4 COOLANT SALT CHEMISTRY 4 4J ClKMtfiY ut SUAMW Ftourakcwa 41 4 2 CorrusmofStiuvinralAloysby Fmoroboraies 42
5 DEVELOPMENT ASD EVALUATION OF ANALYTICAL METHODS 44 51 m4aKAnafestraquo of Molten MSMtFnel 44 52 Tntmni A t f M Esperanents bull t Coutat-Salt Tedhnofagv Facnfcty 45 5J Ekctnlaquo^Kfic^Si^Maflralaquoll|aiMahaiLi -BeF -TM laquo
( T M 6 - i laquo ^ l 47 5 4 Vidummetnc Sankes of Tdnmnn m Molten LnT-BeF -ThT
lt2I6-I2 bull-gt 48
PAST 3 VUlERlAI^ DEVELOPMENT
6 DEVELOrMENT OF MODIFIED HASTELLOYN 52 61 DewelapinesM olt a Moitei Sait Test Fscdicy 52 62 rVocnmneai and Fabrication of Experjnental Almi 65
6-21 Production Heatsof 2 TiJIudrtied HasieRoy X 65 622 SltMfraquooictraquoltNi Keats of 2t TtModmcd H s N
Cammm Stdbmm 6raquo 6J WeMabiny afCanneTcni AlowgtModified HastetVn N 69 64 SUDdm of V m w Modified Hmrikn N Aloys m me
L nnf jdmed Condition 74 65 Mtdumcai Properties of Tiljmdashw Modified Hasietttn S Aloys
bull nW Umnndnied Condition 7 66 IVMirrsdnmn Creep Properties of Modified Kxuelloy N 82 6 7 Mkratntctwral Anah-raquos of Tnawm4lodified HastetVn N 84
671 MKroMracwnl Analysis of ABoy 503 and 114 85 672 HomopefctotisHastctoy S Aloys 88
6Jraquo Salt Corrosion Sindies 91 681 Flaquoe Silt Thermal Convection Lraquoraquops 93 682 Foci Soil Forced Circulation Loop 94 6 J raquo 3 CoolaMSalt Tfcennal ConvectionLoop 94
69 Corrosion of Hasaenm N and Otner Aloys m Steam 97 610 Observations of Reactions n M-talTeiliinum^i System 100 611 Operation of MetalTeHvnam-Salf Systems 101
6111 IHkumm Experimental put gtunVlt I 101 6112 Oironnnm Telunde Snfcmrfity Exprnmer 102 6113 Temjnwrt Experimental Pot Number 2 103
612 Gram tnawdary Embrittleinenl of Hasteiloy N by TeHuriwn 103 613 X-Ray Identification of Reaction Products of Hastetloy N
Exposed to Trikimm-CnnianMnit Eimromrents 107 614 MetaflografnW Exammatmo of Samples Exposed to
Telwnum-Canianwnii Environments 108 615 Examination of TeGcn-l P 119
6151 MeialopaphK Observations 123 6152 Chermcd Analyses for Temirium 124
V
fc16 Salt Prepantni aad Fad Fm Fafelaquo for TEGea-2 aad -3 131
7 FUEL PROCESSING MATERIALS DEVELOPMENT 132 71 SUCK CapMkTlaquob of Gfwhile with BoHMka^
bullKawm-Lrifcaaa SUMIMMK 132 7 2 Thermal Grlaquoaer Maraquo Transfer T laquo of Graph
maMofcMeaamLoap 133 T2I Wea^tChanan 133 722 Coaa^sttoaalCkaaats 133 f23 MkroMractwraiOnagri 137 7 24 DBcmsHN of Rente 37
PART 4 FUELPROCESSMC FOR MOLTEN-SALT REACTORS
a ENGINEERING DEVELOPMENT OF PROCESSING OPERATIONS 142 HI Metal TransferProcessDevelopment 142
111 Addrtion ltM Safe and turna Pka^ ir Metal Transfer Experanezi MTE 3R 143
12 R M d-l 144 a13 R raquo V 145 al 4 DrwwKM of Remits 145
a 2 Saftntoaiwir Contactor Dewdopmenr 147 H21 Lxpeirnents with a Mechanically Agitated Nnnitiprnwi Contactor
bull ike Sah-Ruamth Flowthronfi Facaify 14 a2 Evperiments with a Mrdumcafry Agrtatcd Vindiipri mi
omactor Una water and hVrcury 149 H3 Contavjoas Fhjonaator Devdopmert 152
a3 I histatbtion and Initial Operation of Autoresittance Heatmi Ten AHT4 152
a 3_ Drsam of aCoatamons Fuonaator Expenmeat Facdny iCFEFl 155 K33 Hmonme Disposal Sync for Md 7503 156 H4 Frozen WalCorrosion Protection Demonstration 156
a4 Fad Recnnstifation Enpneernt- Development 15 H41 Imtnaneniatton lor Anatynap Reaction Vessel Off-Gases 15a a42 Deng of the Second Fact Reconstitaoon Eapneermc
Experiment 160 85 Conceptual Deagn of a Mjlten-Salt Breeder Reactor Fad
Processing Engiaeermg Center 161
PART S SALT PRODUCTION
9 PRODUCTION OF FLUORIDE SALT MIXTURES FOR MSR PROGkAM RESEARCH AND DEVELOPMENT 163 91 Quantifies of Salt f-rodaced 163 92 Operating Experience in l2-m-diam Reactor 163
921 Charging and Mrfimg ltA Raw Materials 164 922 Hydrofluorination and Hydrogen Reduction 166
93 Summary 166
ORGANIZATION OIART - 167
PAST I h B M D E 5 raquo r a AND DEVELOPMENT
J REnael
I Srsvcavaad AmJrait
CaVnaatnms c4 the expected trnmm tcknor in refoessce-deagn MSMt a m loatmuid wall stmVcs of the uoanbte effects of ovale rams on heat ex chaff surfaces in the steam system and on surfaces exposed to the ccmaimmtm atmutawew The presence of oxide A n vjnraquoH laquoery km ptimubmty on the heat toaster surfaces would SMstnVaaey reduce the rate of intmm nwgrgrion to the steam system became of the mciemmg importance laquoltf the oxide-Am resistance at very km parshytial pre a w i of hydrogen and irnnaa l lowexi the reduction irom this effect alone would be rnuufficieut to heat rbe rate of tritiuui msginion to the steam system t J denied tames At rates ltd tritium irans-pori le the steam system the presence of oxuk-fam rcastatccs ltm loop wait tends to mcrease the rate of frinsra Hem mto the steam However tins effect a mukpufkaat at the low migiatiiw rates required
Potential ^inbwuonj of tritium m the ruotmt-Snh Technology Facmty were estimated for the cundrtmus o planned expenments In the absence of inborn rater-^ctioe with the salt other than mnpk ihisututici as ranch as laquoW5 of the added tnthaa cowU be expected to escape through the loop wals Removal of significant fractions in the loop off-fas coaM he expected uaH i the effective permeabmty of the loop watts were 10 to 100 times less than that of bare metal
Substantial chemical interaction of tritium with Nnaf 4-NaF was observed in the two tritium addition tests performed Ratios of cornbmrd-to-efcmnilal tritshyium in the salt inferred from elemental concentrations in the off-fas and combined concentrations m the sail were 50 and 530 for the two tests Approximately pound to of the dded tritium was removed in the off-gas stream prindpaly in a chermcaay combined water-soluble form
An undated aeutromes modrl raquot the lOOv-Mtftci releteace-dcsam MSMt r heme developed Muhi-duneanuaat mntagioap cakwUtmas wdi me the VENshyTURE code with newt run crosfsectson data dented catNcK from the fcNDF-IV Wwantv Pruoriune bull the croavteefMW dau was completed tor 3 otJraquo nachdo at lorn temperatures gtJt mtemi lot the planard cakvb-i m v Crow-stetson dau are also heme exammed it the two-step thenaai reaction Nangtr lt Naij i lrf winch is expected ilaquoraquo be the principal to sxe ot hebum m MSMt stractaral metals
A review of i he dau and cakubtsuns medio estauatc tdtunwe mveutories m the TeGen-l experMKM m-catesanuaccTtamtgt ltbull Xr
Work raquo contmaHNj raquo the udgt bullgt thrruul rotvh-ettmg and creep fafaw m react vtrwctural nuternh Analytical ractbodS are bemg developed which wdl be apphed Ss reference-design MSMt ilaquogt evaluate the significance of these processes m HattePoy N
The (ins-Systems TechnoVigy racdtty was ilaquoperated with water throughout the report ptnod Efforts to reduce the annua um ltH the salt-pump shaft oscdbtiom have been unsuccessful The jmyunudt of these oscdb-tions rs brgety dependent upon vk laquoi w ed so a bger-dhmeter imprler which wnl give the design flow and head at kmer speeds rs heme fabneated A method was developed for estimating the pump fountain flow Smce this flow was higher than desirable bach vanes wtl be used on the new rmpener o bnui the How Tests made at the loop indicate that the densnometer can be used to determine bubMe-sepiralar efficiencies if short-term tests are used
Routine operation _ltf the (oobnt-Satt Technology Facility was esiaMrshrd with more than 50Ghrof sah circidation without plugging in the loop off-gas Nne Measurements of the amount ot salt mist in the off-gas stream showed 100 to 500 ngcm iSTP) depending on
VII
1 M
w
l t
I BLANK PAGE
bull-laquo-
laquo t u
the a l t temprrataK and the I F flow rale MMO ike loop gas space The M M trap awtaard m the sah cold trap was effectn m meanta ike pm^mg hraquot had been expeneaxd earner Two i m i a marcoon lesti bullere coadacteJia whjch 85 aad bullraquo cwTi teaarvtwds of ifitmed bydropea ere added to the loop dame two I04raquo periods- Ficqaeat n i l aad off-gas sample were takea to mumlor the tRtaaa bebamor m the kwp
The torcedltoarctwa loop MSat-FCL-2b has accw-rautatcd MOO hi of oneratnaa with MSMl reference hart vdi at deaf ^ r coadmoas wrm riW expected low O M -roaoa rates Dbu oMaawd oa the beat master ckarac-terufacs of das sak air being aaafvard The deaga B eaeaadK complete for torced-coawectioa loops FCL-3 aad FCL-4 Coaaaoaeats ate beaaj fabricated J dec-tncal a i i f lHwia is proccediag
PART 2 C V E M S n t Y
3 Fari-MtCfceaaMry
Refachch pare Li Te lahoat lt oa a mole haasi bullas piipaatd by the coatroaedaddrooaof Kaaraaa to Hiaad hdnum The lac tam was began at 15QT bat afciamefjr tempt Mimes greater thja 50tTC acre reshyquired to complete the reactwa LiTe was prepared by rcactmg the aoidaomrtric amounts of LijTe aad tcfa-raan f o r brat 550^0
Apparatus for the spectroscopic stady of letunam species ia MSMt far salt has beta aaeaawed rYeima-nar work am hnmaa teshmars ia cbkmde taehs has shown ant at least two Mfbi-abjurbaig spears are present wirh uwapoatuai at the raja Li-Te to UTe Farthenaorc stadia with T e ia LiO-KCI eatectic have shown that laquo addition to Telaquo a lecoad species is present at high lemperatewH aador lag habie km activity
Apanxtm for the qtearoihotometric stady of the conawriam UFlaquo(dgt bull 4H 2 iggt = UFidgt bull HF|graquo has beea assembled aaa measurements using LiineF as the sointnt haw begaa A prehaaaary valac of aboat 10 was obtaiacd for the eqiaktiiam quotient at 6S0degC Tins vaiae is ia good agreement with the valat obtained pnwoady by other workers
Detopmeni proceeded on porous aad pact d-bed electrode systems as coatiaaoas on-line moailors of conceatralioas of declroactiwt species in molten sail solutions The packed-bed electrode of glassy carbon spheres was caNbralaquo4d using Cd 1 ions in LiCI-Kfl eutectk before experiments were conducted with B ions in solution The results of the experiments demon-straied the cpabdity of the electrode for momioring these and other ions
Preunaaary eiftrraacar i n c conducted iraquo cvatiaic watt ^wntkKM fetatmg to the naxmg bullbulllaquo VaBr - jF coutaai sah with M S M tiid vdi D F - f k f - H i r 4 F tMfc-ll ~-0S mute I Ibe result showed that ihr rate of erutatjoa oi BF gas raquoa naxau was low Mi vac of sanf amounts m coolant vdi wtth fael tab Jal bulllaquo result at the purctpttatam M aramam- ltlaquoc ibiwaaa-coataaaac -antpuands Vlt data w^re abtaaed +m ibr aaxaa M sanfl aaamats ot farl salt wwh o4aM vW( HesahstHeiprraataiiMi whvh a satal amtaai ot on-l aat salt cuataaaay igtxale was aaed with tael salt sae-eraed d m oude speoes aawe stable dun I O wlaquotc pMseat smce bullgtraquo pitecipitjnua of I O was raquodraquosrtraquool
A stads ul laztice eadadaKs ot tirst-ruw traassfiua-atrial (Wndcs was aadertakea to proadr a theraquofciicjl basts laquobullraquo ii itll Haw thrnancbrnacal data Urn uraLiaial metal tlaondes bratg obtaated from mm4 eitctrcisie gjiiaaJL ceKs I igaadnrid comctamsto pkxsul lattKe emhapy laquos ttnaat aamber for the rwraquoraquo senes CaF laquoo laFz raquo ScFgt to GaF mdkaied that dte staadad embdptes at loranfua plusmntf gtol N jad V F weilaquo saostaclors bat dial a m accante expcraaeatal lamn of Sit fur T i F V F O F CrF F e f aad FeF woald be deswabh
Analysrs tlaquot raaplr i ot coaJeasate coarcted danat opnaiwa of the Cooba SJ Tccbaolagy Facigt nahcate that the mpur aboar the gtali B aot a taaie mokvafar coeapoaad bat rather a auxtarc ot stamk gateows species sach as H 0 HF aad K F The coadtn-sate dtowed a intmm coaceatratioa ratio of aboat 10 rentiwe to dar salt Tha resak tajatsts a pinablc method for coaccatrafiag aad collectiag tntiam -a aa MSMl Related work showed that NaBF0H dnnohed ia ^ltobal sah uadergoes a reactwn that redaccs the OH ~ coaceatratioa m the salt prodacmg a mbtde frac-tkm Phyacal aad chemical obstrtalioas were made on the sysem VaF-NaBF-BjO at 400 lo oOtfC Work with compoaikms typical of ibe usual coulaat salt (oxide coaceatratioas up to 1000 ppm| showed that at least two oxygea-ooataaaag species are present One species n N a raquo F raquo 0 the other has not yet been bulldenirfied
Slddtes were continued o determine the extent lo which borides were formed in Hbstetoy N and btcoael 600 by reaction with NaBFlaquo-NaF at 640degC Data obshytained thus far indicate some formation of chromium and nickel borides however after four months of exshyposure of the alloy samples lo sal the boride concentra lion on the metal surfaces did not exceed 500 ppm in
I X
Haste X and 1000 pom m hwoaci MM) The tcvdh jhraquo dtuwei that A n mdash i n n these laquobullgtbullgtgt was setec-incigt gtraquodued by rhe salt
IkMb thrv period I I ~ ratio were oMMoted by laquogt4taaMneirv lechnnnsrgt in imu rhetmai-cunvecSoa loop and ltAC oiced-circgtdaraquooa loop Subie redox mo dnom H4MIHK bullbull exist m tbmnal-convrctiou loops U A ) 2V the I I ut9raquo raquo approximately T A IO ani respectively In forced-cunvectampn wop H I - gt she I I rlaquoraquolaquo n about copy Vraquo meinpfs feme et Keen ante laquobullgt reoxuJur the I i fhe melt by the addition ot mchet tiuundelaquolaquo some other oxidant
The results rora the fast series of tntnuu ldditmn experiments at the ( raquo u b n - U i Tcdmulugy Facem ltholaquo (wraquo ten tattle mimm exist m the off-gas m the ctesnental state the bwtli of tbe tntruei ltvwi at i iuai-huved laquo water-Mi Ale K m h appears thai about W of the uuecttd inmm experienced tvawticanf holdup raquo thr salt -and was eveutualy remmed m the system ott-
It was observed that the Fe - Fe electrode reacshytion n molten LraquoF-leF-ThFlaquo lt~2-l6-l2 mok i ckfseH approximates the soluble product case at a guid electrode the inwduMc product case at pyroiytic graphshyite and- deptwdmg on the temperature both soluble and insoluble product cases at an indium ekxtrode
Yoffarmarirw measurement were node m muMen liF-nVF -fhF 4 toSowute jddrtiuru tit Li Te is an effort to identify soluble etevitoactive lehurium species re the melt No soitammetnc evidence of such comshypounds was ohtaated These observations were m general agreement with cherracal analysis that indicated lt5 ppm Tern the salt
fAKfi MATEMALSKVF4j0PMtIVT
u Dtncfupmvnl bull bull MMuinJ lunumvy 3
Work raquo parfnHy complete on the molten-salt test facrlrty to he used mostly for mechanical property testshying Much lt (he test equipment is oprralmn
Alt products except the seamless tubing of the V-Ti modified HasteHoy N were received The first heat weighed lOjOOO Ih and had a fairty narrow working lem-prrature range- The second heat weighed WOO lb and had a wider winking temperature range Seamless lubing is being fabricated by two venders WeMahility studies
on these two beats showed bat their urldnsg d u n e lettstacs were euuwahm to those ut standard Hatfefoy V and thai extstmg wetdng procedures ut standard HaMcwoy could he used fur the y Ti Audited
The mechanical properties of HasteBoy gt inuiiaed wwh ifUnMtm nwhrum aad aiunuMun were evahaied m the undated and uwrradnted MB These piupertjcs were umd to estunate tfae mdwudwd and courtuntd wOBceMtauans of Manwani muhwun and ahnuuHnn reouwed laquou produce bntrte mienueuBK phases The tomnuuu ot brstrk phases m the aloy n i t mdash n muwuni was enhanced by an apphed stxss
SpeciBMns ot modihed HnseSoy were exposed to idlunuw from several dMterewi sources Tbe partial pressure tH tewynum above CrTelaquo at TOO C sMtm reasoatfjty dose to that anttcaujied tor MSMb Metal-lugraphic e-umnitiua o tbe exposed specuuens aite strauwnt revealed iblaquo aftoss coniauung OS to I Nb were resttfant to neTgnnular craefcrng by teiurrum
Further aaatysn ot the data lrlaquown TeGen-l showed that most ot the tdunum m each fuel p s was coircen-tafed on the tube wall The concentration bullraquo the salt was I ppm gtrr less The salt bssbcen preparew igtit gtugtng the fuel pur m TeGen-r and- and the puu tor Telaquoelaquo-- base been assembled tlte tuhng
t ipenments were contused laquobull-gt evaluate graphite as a matenal tor fuel prlaquolaquocrsssng apphcaimus The peneira-tmn ot graphite by buRtuth-utbimn suiutnms was found tigt increase with mcreasmg lithium concentration of the stdutKm and pore diameter of the graphite Decreasing the pore dBrneter or the graohae by pitch impregnation decreased the average depth of penetration However because fhe structure of the graphite was sarobie greaier-fhan-average penetration occurred m reginns bullraquo low density
A thermal-convection loop construcied 01 irkdyb-denum conumed ATJ graphite specimens in hot- and cold-let reports and circulated Bt 24 wt bullbull 141 at t Li for WOO hr at 700 C maximum temperature with a temperature differential of I00degC Very large wetghr mcrextes tJO to tgtT~ cccurted in ail ot the graphite samples primarily as a result of bhmuth intrusion into the open piMouty ot fhe graphite Disamclar-metal mass transfer bet weep molybdenum and graphite was also noted These results and previous capsule test results suggest that fhe presence of mofyhdenum enhances intrusion of bifrnuth-lithium solutions into graphite Thin carbon layers were noted on the molybdenum
X
PART 4 FUEL PROCESSING FOR MOLTEN-SALT REACTORS
8 EsgMecfMg Dcvdopraest of Piocessiwg Operations
Addition of the salt and bismuth solutions to the process vessels in metal transfer experiment MTE-3B was completed Two experiments were performed to measure the removal rate and overall mass transfer olaquofficients of neodymium In the first run about 13 of the neodymium originally added to the fuel salt (72-16-12 mole UF-BeF2-ThF4) in the fuel-salt resershyvoir was removed durine the 100 hr of continuous operation Overall mass transfer coefficients for neoshydymium across the three salt-bismuth interfaces were lower 1ian predicted by literature correlations but were comparable to results seen in experiment MTE-3
For the first 60 hr of the second experiment which was a repeat of the first experiment the rate of removal of wodymium was similar The second run was termishynated because of unexpected entrainment of the fuel salt into the lithium chloride in the contactor which resulted in depletion of the lithium from the fh-Li solushytion in the stripper and stopped further neodymium transfer
Future experiments in MTE-3B will depend on detershymining the reason for the unexpected entrainment of fluoride salt into the lithium chloride and it will be necessary to remove and replace the lithium chloride that is presently contaminated with fluoride salt
A hydrodynamic run intended to determine the effect of increased agitator speed on the extent of entrainme w OIK phux uw tne other in the salt-bismuth conshytactor was performed No visual evidence of gross enshytrainment was found Analytical results indicate that the bismuth concentration in the fluoride salt phase decreased with increasing agitator speed This unshyexpected result is probably due to sample contaminashytion
Development work continued on an electrochemical technique for measuring electrolyte film mass transfer coefficients in a nondispersing mechanically agitated contactor using an aqueous electrolyte solution and mercury to simulate molten salt and bismuth During this report period experiments with Fe-Fe2 were nude with improved experimental apparatus A stanshydard calomel electrode which enables measurement of the mercury surface potential was obtained Electronic filters were attached to the inputs on the xy plotter to damp out noise in the signal to the plotter Near the end of the report period a potentiostat was obtained which will automate the scan procedure now performed with
the dc power supply Copper iron and gold anodes hjve been tested The gold anode is the most satisfacshytory choice since it does not react with the electrolyte solution By noting that the active anode area in the cell could be decreased with no resulting change in the difshyfusion current it was determined that the mercury cathode rather than the gold anode is polarized Results indicate that the ferric iron is being reduced by some contaminant in the system Further tests with purified mercury and electrolytes in the absence of oxygen indishycate that the contaminant was present in the mercury Analytical results for Fe and Fe1 concentrations in the electrolyte phase are inconsistent with expected results Qualitative results indicate that a buffered quinone-hydroquinone system may be usefid as an altershynate to the Fe-Fe2 system
Installation of autoresbtance heating test AHT-4 in which molten salt will be circulated through an autoresistance-heatelt test vessel in the presence of a frozen-salt fim was completed and operation was begun A conceptual design was made of a continuous fluorinator experimental facility for the demonstration of fluorination in a vessel protected by a frozen-salt film Design was completed and installation was begun on a fluorine disposal system in Building 7503 using a vertical scrubber laquoith a circulating KOH solution Inshystallation was completed of equipment to demonstiate the effectiveness of a frozen-salt film as protection against fluorine corrosion in a molten-salt system
Off-gas streams from the reaction vessels in the fuel reconstitution engineering experiments will be conshytinuously analyzed with Gow-Mac galaquo density detectors To determine whether hydrogen back-diffusion in the cell body will be a problem during the analysis of the HF-Hj mixture from th hydrogenation column the cell was calibrated with NJ-HJ mixtures It was found that when the reference gas flow rate to the cell is suffishyciently high i effect of hydrogen back-diffusion is not seen The second engineering experiment will be conducted in equipment which is either gold plated or gold lined to eliminate or minimize effects resulting from equipment corrosion Several alternatives for gold lining or gold plating are discussed The factors which must be considered in deciding between lining or plating are listed
A design is being prepared to define the scope estishymated design and construction costs method of accomshyplishment and schedules for a proposed Molten-Salt Breeder Reactor Fuel Processing Engineering Center The proposed building will provide space for preparashytion and purification of salt mixtures for engineering experincnts up to the scale required for a 1000-MWfe)
l
MSBR and for laboratories maintenance areas and offices The estimated cost of the facility is SI5000000 authorization will be proposed for FY 1978
PARTS SALT PRODUCTION
9 Prodactioaof Flwnde Salt Mixtures for Research and Development
Activities during the report period fall in three categories (I) salt production (2) facility and equipshy
ment maintenance and modification and (3) peripheral areas that indwb preparation of transfer vessels and assistance to others in equipment cleanup
Salt produced in this period totaling about 600 kg was delivered in more than 30 different containers About one-half of the salt was produced in an 8-in-diam purification vessel and had acceptable purity levels The remaining salt was produced in the 12-in-diam purification vessel during five runs each of which involved about I SO kg of salt
Part 1 MSBR Design and Development JREnge
The overall objective of MSBR design and developshyment activities is to evolve a conceptual design for an MSBR with adequately demonstrated performance safety and economic characteristics that will make it attractive for commercial power generation and to deshyvelop the associated reactor and safety technology reshyquired for the detailed design construction and operashytion of such a system Since it is likely that commercial systems will be preceded by one or more intermediate-scale test and demonstration reactors these activities include the conceptual design and technology developshyment associated with the intermediate systems
Although no system design work is in progress the ORNL reference conceptual design is being used as a basis to further evaluate the technical characteristics and performance of large molten-salt systems Calculashytions are being made to characterize the behavior nd distribution of tritium in a large system and to identify potential methods for limiting tritium release to the environment These analytic studies are closely correshylated with the experimental work in engineering-scae facilities Studies were started in this reporiing period to reexamine the expected behavior of xenon in an MSBR This work will ultimately use information from experiments in the Gas-Systems Technology Facilitiy (GSTF) to further refine l 5Xe-poisoning projections and to help define the requirements for MSBR core graphite
I Molfen-Salt Reactor Program Staff Conceptual Design Study of a Single-Fluid Molten-Salt Breeder Reactor ORNL-4541 (June 1971)
Additional core neutronics calculations are being made for the reference MSBR using widely accepted evaluated nuclear data and a two-dimensional computashytional model These calculations will provide updated estimates of the nuclear performance as well as add -tional information on core characteristics Analogous methods and data are employed to provide support for in-reactor irradiation work
The GSTF is an engineering-scale loop to be used in the development of gas injection and gas stripping techshynology for molten-salt systems and for the study of xenon and tritium behavior and heat transfer in MSBR fuel salt The faciiitiy is being operated with water to measure loop and pump characteristics that will be reshyquired for the performance and analysis of developshymental tests with fuel salt
The Coolant-Salt Technology Facility is being opershyated routinely to study processes involving the MSBR reference-design coolant salt NaBF4-NaF eutectic Tests are in progress to evaluate the distribution and behavior of tritium in this system
Candidate MSBR structural materials are exposed to fuel sail at reference-design temperatures and temperashyture differences (704degC maximum nd i 39 aC lt17) and representative salt velocities in forced-convection loops to evaluate corrosion effects under various chemical conditions These operations which are principally in support of the materials development effort also proshyvide experience in the operation of molten-salt systems and data on the physical and chemical characteristics of the salt One loop MSR-FCL-2b which is made of standard Hastelloy N is in routine operation two others to be made of titanium-modified Hastelloy N are under construction
1
m BLANK PAGE
L Systems JR
11 TRITIUM BEHAVIOR IN MOLTEN-SALT SYSTEMS
Studies to elucidate the behavior of tritium in large molten-salt systems were continued in this reporting period Additional calculations were made for the IOOO-MW(egt reference-design MSBR to examine the effects that an oxide film on metal surfaces might have on the distribution of tritium Analysis of the informashytion being generated by the tritium addition experishyments in the Coolant-Salt Technology Facility (CSTF) was begun As additional data and results are developed they will be incorporated into the MSBR studies
I l l MSBRCakvbtioas
G T Mays
Calculations were performed to examine the potential effects on tritium transport to the steam system caused by the formation of oxide films on the steam side of the tubes in the steam raising equipment of an MSBR Th rate of diffusion of hydrogen (tritium) through metal oxides typically is proportional to the firs power of the hydrogen partial pressure in the gas phase as opposed to the i power for diffusion through metals (i-e the diffusion process is molecular rather than atomic) In addition at moderate hydrogen partial pressures the permeabiiity coefficients of the oxides may be as low or lower than those of pure metals Thus at the very low hydrogen partial pressures that would be expected in an MSBR oxide films could offer substantial resistance to hydrogen (tritium) permeation However the efficiency of such films would be limited by the degree of metal surface coverage that could be established and mainshytained during operation of the system
The computational model1 for studying tritium behavior at steady state provides for variation of the metal permeability coefficients of the steam-system tubes but assumes that diffusion through the tube walls varies only with the A power of hydrogen partial presshysure Variations in metal permeability were considered in previously reported results However the model also includes the effect of a mass transfer coefficient for tritium transport through a salt film inside the tubes Since transport through the salt film depends upon the first power of tritium concentration (or partial presshysure) this value was used to estimate the effects of oxide films Effective mass transfer coefficients were
Analysts
computed which included the resistances of the oxide films as well as those of the salt films1
Tritium distribution calculations were made for a variety of situations in which it was assumed that the effective permeabilities of the oxide coatings in the steam system were I 10 10~2and 10~3 times those of the bare metal at a hydrogen partial pressure of I torr (130 Pa) These results were compared with cases without oxide coatings in which the permeabilities of the bare metal were reduced by factors of 110 I0 2 and I0 3 The comparisons were made at three values of the UUgt ratio (10 2 10 and 0 4 ) and in all cases sorption of hydrogen or HF on core graphite was asshysumed to be negligible
The results (Table il) indicate that a low-permeability oxide coating would be more effective than a low permeability in the metal itself for limiting tritium transport to the steam system When an oxide film resistance equal to that of the metal was added the rate of tritium transport to the steam system was apshyproximately halved as would be expected (The total resistance to tritium transport was not doubled because of the contribution from the salt film) The results with a factor of 10 reduction in a steam-tube permeability due to oxide formation indicate that tritium transport to the steam system could be limited to the design objective of 2 Ciday However it may be unreasonable to expect to obtain and maintain oxide films of this quality in an operating system
Additional calculations were performed to investigate the effect of reduced permeability of the primary and secondary loop walls through the formation of oxide coatings These coatings can be expected to form in a manner similar to those expected on the steam equipshyment For a given steam-tube permeability reducing the permeabilities of the loop walls would be expected to increase the amount of tritium transported to the steam system With the reduced loop-wall permeabilities less
1 R B Brig A Method for Ctlculalmr thr Steady Sute Distribution of Tritium in a Molten-Salt Bre jet Reactor Kant ORNL-TM-4804 raquoApril 197)
2 G T May in MSR fmgram Semiamtii Progr Rep Feh 2 1975 ORNL-5W7 pp3 12
3 Although ihri calculalional approach assume thai the oxide film i located inside the tubes rather than outside it can be shown that for given oxide and metal permeaMifie this irrangement slightly overestimate the rate of hydrogen permeashytion through the wall
3
TaMe t l Effect of oxide Wmdash on uitmm i todeamtrttmatm MSUtlaquo
Rjti of oxrior raquolaquolaquo laquobull H inlw ltlaquo meial permnbiliiy Imdash 1 tieaw iytteraquo lOday I io nominal metal ratio 0 i d film Redaced meial
prmKabriiiy mvae tlaquobetr prrambibiy4
1 I 0 811 142$ 1 10 J 656 1169 1 10 115 203
10 10= 173 1351 10 bull 10 138 114 10 bull 10 23 198
10 ltf 19 662 10 I 0 J 16 575 10 10 3 142
10 gt w 2 93 10 10 15 84 10 10 lt 31
No wrption of H or HF on core paphtte At a hydropen partial prewurc of I ion
rWith nomnul meul permeability ^No oxide film
tritium would permeate through the loop walk into the primary and secondary system containments eliminashyting a potential sink for tritium A higher tritium conshycentration for partial pressure) in the secondary system would result creating an increased driving force for tritium transport to the steam system
The result of the calculations did indicate that with out the presence of a chemical getter in the secondary coolant more tritium was transported to the steam system when the primary- and secondary-loop wall pershymeabilities were reduced than in the same cases with reference permeabilities for loop wads However more importantly for those cases where tritium transport to the steam system had been reduced to the design-timi abjective of 2 Ciday through chemical additions of H HF or a chemical getter results showed essentially no increase over the 2-Gday rate Thus it appears that reduced loop-wall permeability hat little effect on tritshyium transport for cases where a tritium exchange mateshyrial is present in the secondary coolant
1 1 9 f^^a^af ^dgt T^haMwaflV frMsawv
J R fcneH G T Mays
A 1000-MWe) MSBR is expected lo generate about 2420 Ci of tritium per full-power day Calculations showed4 that unless a major fraction of this tritium
were converted to a chemical form less mobde than elemental HT the rate of migration of tritium through the metal walk of heat exchange surfaces to the steam system could be unacceptaMy high The purpose of the tritium addition experiments in the CSTF is to simulate the general conditions in the MSBR coolant-salt system to determine the extent to which tritium can be held up in the NaBFlaquo-NaF salt There is evidence that hydrogen-containing compounds in the salt may retain significant amounts of tritium
In the experiments the first two in a planned series tritiated hydrogen was diffused into the circulating salt through the walls of a hollow HasteUoy N tube The tritium could accamuiaie in the salt pas into the off-gas system or permeate through the metal walk of the loop to the ventilated loop enclosure Tritium concenshytrations were monitored in the salt and in the loop off-gas In the firlaquo =o experiments 85 and 97 mCi of tritium diffused through the HasteHoy N injection tube For a detailed description of the experimental condishytions see Sect 22
The computer program5 for calculating the expected tritium distribution in a 1000-MW(e) MSBR was modishyfied to describe the CSTF and was used to calculate potential tritium distributions for the experiments under the following assumptions
1 steady-state conditions 2 only dissolution of elemental tritium (hydrogen) in
the salt with no chemicai reaction witn the salt or any of its components
3 all transport through metal walk varies as the power of hydrogen partial pressure
Calculations were made for addition rates o( tritiated hydrogen equivalent to those achieved in the CSTF exshyperiments using assumed loop-wail permeabilities rangshying from the value expected for bare metal to 10 of that value The results (Table 12) show a significant effect of loop wall permeabiity on the fraction of the added material that could escape through the wafts This table also shows the calculated steady-state concentrashytions of elemental tritium in the salt (nCig) and in the off-gas (pCicm) in the same units that are being wed in reporting experimentally observed conjurations Abo shown are the inventories of elemental tritium in the loop walk that would be associated with the calcushylated transport rates through the wafts Since these cal-
4 G T Mar- m MSB fhjpmm Semhwrnu Prop Hep Feb raquo I97S ORNL-5047 pp J 12
i Hraquo bullltbull ami C W N M j r A Method ft e CtkuUting Ihe Sternly Sime DtttrHmitut of Tritium m t Molten Saft Krrrdrr Kemcior Uml 0RNLTM-UO4 (April 19751
Table 12 Calculated rieady-Male tritium diitrrbuliorw InCSTF foe experimental addition rale
Additi on rate Loop wall Tt ilia ted permeability mixture (fraction of hydrogen Tritium bare-metal Kmraquohigt tmCihr) value)
3 1 79 1 10 10 bull 10 bull
3 3 C 93 io-laquo 10 bull 10raquo
Time to reach 8Sf of steady-
state conditions (hrl
Fraction of addition rale which permeate
loop w-y (it
elemental tril removal in oil
turn r1Hraquo
Klvntental tritium Time to reach
8Sf of steady-state conditions
(hrl
Fraction of addition rale which permeate
loop w-y (it
Iraction of addition rate removed
CD Concentration
tpCicmi
concent ration in tlaquolt traquocigi
03 994 06 400 13 95 771 229 I5IKMI 50
38 149 851 55000 200 42 16 984 64000 2211
03 994 06 5(HI 17 103 7$-raquo 243 I90IJ0 (gt4 37 143 HS7 fi7000 230 42 I S 9S5 77tMM 26tl
Irtiium inventory
in metal walk Kti
01 oK 16 17
013 10 19 20
Sail and oil-gas concentrations only longer times required for steady-slate permeation through loop walls
0I tritium in hydrogen
01 I l tritium in hydrogen
t
s
oriatmas represeai steady-state coadmoiaad the nt-naa additioa experaaeats iavolwr t raaskats it a asefal to cuaader the taae renaaed to reach the steady state At high loop-wal penaeabihiies the coaceatratioas of ekaMRtal bullrtraai m the salt aad off-gas are low aad lead to -each steady vataes qakfcry for die additioa rales (see Table 12)- Soaiewhai toager u
aied arith lower assaned loop-wal ptrmdashnbiam hi al cases iidinaiiialjr I n a y times are niaawd to reach steady-stale rates of tiitiaai release throa|h the loop walls However this has little effect oa the triturate steady-stole levels ia the sail aad off-gas
Figures II aad 12 show the resatts of intiwm cua-ceairatioa raeasareaMau v the salt aad off-gas from
are reqaired to reach the higher coaceatratiaas assoo- the CSTF dariag the first aad secoad irilian addition
tn a m - M B laquo raquo
lO _ I 1 - bull ~~l 1 1 1 1 1 1 1 ^ 5 mdash
O SALT llaquoC | )
bull 0raquoT-laquoAS WATER SOLUBLE t$CiJtmh
A 0FF-euroAS ELEMENTAL (aCiar)
1 Mil
2 bull f
bull0
_ 5 n
poundL_ bull0
_ 5 n
mdash
bull mdash
mdash J jy^TRITIUM ADOlTlON bull mdash
2 2 bull II mdash
oraquo II ^ 10 G c
i s
pound 2 z tal Z I O
bull
0
bull bull
bull
A
bull bull bull
IIIIIJ 1 1
s 0
0 mdash
0 mdash
I 5 s
2
10deg
mdashb bull
e
a
e O
A A
A A
I 5 s
2
10deg A A aaw
i bull bull
s
2
bull -
bull i mdash
in- i 15 17 1raquo 21 23 25 27 29 Si
JULY OATCttTS
Fjj II Ofctcfvclaquo4 tnttvui cottt9MnHtottinCSTF 9ttn I
5
2
5
2 mdash
9
u 2 mdash
H = -S bull o u S 3
2 -
^ raquo mdash
5 h
2
bull0deg
raquo
2
mdash 1 1 1 1 1 1 1 1 = ~ O SALT (laquoCi l mdash bull 0FF-6ASVATCR SOLUBLE fcOA-i5) ^ mdash A OFF-CAS ELEMENTAL (f Citw5) mdash
^mm
a ^^ mdash^ 1 ltlaquo bull raquo I 1 1 4
^^ mdash 1 1
1 4 ~ trade
I bull mdash
bull
bull bull
I bull
I bull mdash I bull mdash
=
U
KITH KM A DOtT ON _
= bull
bull bull
llllll 1 1 1 1 V
bull
mdash
bullr T 0 ^
laquo bull 1 A A ~bull r^^ i S 0 O mdash mdash i S
A A ~~
0 0
e
51 A o = ^v 1 M M
mdash 4 A o-
mdash 1 -
bullbull i
T t If traquo bullraquo OATC MJtutT laquof7raquo
IT laquot 21
bull M M M ti cvrr MM i
7
tests The concentrations reported for the salt represent tritium in a chemically combined form since any eleshymental IfT trapped in the samples would have been reshyleased in preparing them for scintillation counting The tritium in the off-gis was present in two distinctly difshyferent cheriksl fonrr Part of the tritium activity was present in a water-soluble form implying a chemkil compound since HT does not interact significantly with water at room temperature The other form is presumed to be elemental HT since ft was trapped in water after passage of the sample stream through a bed of hot CuO
In all cases the results are presented in Figs 11 and 12 as reported with no corrections for apparent baseshyline concentrations However the results of samples taken before and after each test suggest that nonzero baseline concentrations were present The apparent baseline concentrations for the two experiments were
Itfexpcrineat Mcxatrineat
In uli 17 nCig I nCig In olT-cas elemental I pCicm1 I pOcm In off-jta water oiuMe I pCicm3 50 pCiere
During the tritium addition period for the first experishyment the tritium concentration in the salt (Fig I I open circles) increased almost linearly to a maximum of about 100 nCig and then decreased approximately exponentially over the following 3 to 4 days to its preshytest baseline concentration In the second experiment (Fig 12 open circles) the tritium concentration in the salt reached a maximum of 70 nCig and returned to the baseline concentration about 6 to 7 days later If baseshyline corrections are applied to the salt-sample data the apparent half-lives for tritium removal from the salt for the two experiments ar 92 and 12 hr respectively
If tritium removal from the salt is assumed to be a pure first-order process or combination of such procshyesses and if it is assumed that the processes were also active during the addition period the buildup of the tritium inventory in the salt (for a constant addition rate)should be described by
J M I O - i l l - bull ) X
where
V() tritium inventory in salt at any time I during che addition
A tritium addition rate
A lime constant for the removal process (or proc-esats)
I f several first-order processes were involved bull the intshyrant removal from the salt the time constant X would be the sum of the several individual time constants but the individual values would not be identifiable Substishytution of the actual addition rate into this equation gives the expected tritium inventory in the salt at any lime i f all of the tritium were reacting with the salt Conversely substitution of observed inventory values permits evaluation of the effective addition rate (the rate at which tritium did react with the salt) In either case the results may be expressed as ritium trapping efficiencies with values of 85 and 50 respectively for the two experiments These trapping efficiencies imply that significant quantities of the added material were reacting with and being trapped (at least temponriy) by the salt Data from the second experiment suggest the presence of other mechanisms with significantly longer time constants for removal of tritium from the salt Because of the apparent scatter in the data at longer times the extraction of these time constants was not attempted
The water-soluble tritium in the off-gas during the first experiment (Fig 11 closed circles) did not inshycrease significantly until after the injection was comshypleted and then rose to 1750 pCicm 3 The level then dropped rapidly to about 50 pCicm 3 rose again to about 300 pCicm 1 6S days after the addition and then decreased to lower values In the second experishyment the water-soluble tritium in the off-gas rose rapshyidly during the addition period and reached a maximum value at the end of the addition of 13100 pCicm 3 Abo the ratio of the concentration of water-soluble tritium in the off-gas to that of the elemental form was substantially greater in the second experiment than in the first
Owing to the apparent scatter in the data involving the water-soluble tritium in the off-gas for the first exshyperiment no quantitative evaluation was attempted However in the second test the initial decrease in conshycentration has an apparent half-life of 18 hr but the data again suggest the presence of other time constants An attempt was made to separate the time constants by assuming that the decay curve was made up A two simple first-order exponentials This led to apparent half-km of 9 J and 37 hr for the two processes Numershyical integration of the water-soluble tritium data for the second experiment yielded a total flow of 58 mCi through the off-gas line during the removal period and 75 mCi during the addition period Thus a total of 65 mti or about 65 of the tritium added is accounted for as combined tritium in the off-gas stream during this test Since the concentration of elemental tritium was
8
always less than 001 of the combined tritium concenshytration the presence of any elemental tritium does not significantly affect this observation
The concentration of elemental tritium in the off-gas samples rose during the addition phase of each experishyment 2nd apparently began to decrease as soon as the addition was stopped The maximum concentration in the first test was about 800 pCicm3 and only 40 pCicmJ in the second In both cases the decrease in concentration with time after the addition was too irregular to justify any quantitative evaluation
Although no measure of elemental tritium concentrashytion in the oalt a available a value can be inferred from the concentration in the off-gas by (1) assuming that the elemental tritium in the off-gas samples represents release from the salt and only from the salt and (2) assigning reasonable values to gas stripping parameters in the CSTF pump tank Concentrations of eiementai tritium calculated in this way indicate that the ratios of combinedelemental tritium in the salt were about 50 and 530 in the first and second experiments respecshytively It appears that chemical interactions between the tritium-containitg compound in the off-gas and the new metal of the sample line may have been responsible for the high concentrations of eiementai tritium in he off-gas samples from the first test and that the actual ratio of combinedelemental tritium in the salt may have been higher than 50
The inferred maximum concentration of elemental tritium in the salt during the second experiment is about 013 nCig Extension of the calculated tritium distribution with nominal metal-wall permeability (Table 12) to lower concentrations indicates that at 013 nCig tritium permeation through the loop walls could account for no more than about one-third of the tritium added to the system Since this is close to the amount not accounted for in the off-gas samples it appears that the effective permeability of the loop walls is near that of bare metal
12 XENON BEHAVIOR IN THE MSBR
GTMays
The computer program MSRXEP Woden-tali Rate-tot Xenon Poisoning) describing the X e behavior in the reference-design MSBR was used to perform calculashytions to study the effects of the Knudsen diffusion coefshyficient for xenon in the bulk graphite and graphite coatshying of the reactor core on the X e poison fraction The program has been described previously bull7
Following the fission of the fuel the decay of the mass-135 fission fragments is assumed to follow the decav chain shown below
l l
5 X e (1529 mm)
135 s C i J 135
(659 hr) Ba
(30 X 10 yr) (stable)
This diagram illustrates the half-life of each isotope and the branching ratio of the 3 5 1 decaying to 5 m X e and l 3 5 X e assumed for this study Along with this decay chain the following input data were used
Bubble concentration 44 bubbles per cubic centimeter of salt
Total helium dissolved in salt and present in gas bubshybles 10 X 10 molecm3
Bubble separator efficiency 907
For these conditions the mass transfer correlation in the program gives a bubble mass transfer coefficient of 00166 cmsec which leads to a loop-averaged void fracshytion of 055 with an average bubble diameter of 065 mm The calculated 3 f Xe poison fraction is 00046
The reference Knudsen diffusion coefficients for the bulk graphite and graphite coating associated with the 00046 poison fraction are 238 X 10 and 258 X 10 cm2sec respectively The bulk graphite values were varied from 258 X 10 to 258 X 10 cm1sec assuming no graphite coating was present (Table 13 cases I 3 5 7) to observe the effect on the poison fraction The low-permeability graphite coaling - 028 mm thick was assigned bulk-graphite values for the Knudsen diffusion coefficient and porosity making the coating part of the bulk graphite for calculation purshyposes Under these conditions the porosity of the bulk graphite was held constant at a value about 31 times
bullThe complete units for diffusion coefficient arc (cm ps) (sec bull cm graphite)
6 H A McLain el al in MSR Pmgrmn Semttmu front Rep Aug 31 1972 ORNM832pp If 13
7 H A McLam et at in MSR fmpwm Stmiumu Prop Rep Feb 29 1972 ORNL-47K2 pp |3 16 17
9
Kmfara M i a s m cocflkatat l c raquo p v laquo c -en graphite) CakabKlaquo1 Xe
DOHOB fractna M k f r a p a i K Graphite coati
CakabKlaquo1 Xe DOHOB fractna
1 258 x 10 Socoanag 00153 2 258 x 10 258 x 10 bull O0J52
3 258 x 10 No CiOMg 00140 4 258 x 10 bull 258 x 10 7 00I4S
5 258 x 10 bull Nocoatne 00113 258 x 10 bull 258 x 10 00107
7 258 x 10 No coalBaj 00077 8 258 x to bull 258 x 10 c 00044
M t graphite porosity ralae RKMH COHSUHI in ail cam 31 t met greater than rhe valar for ike graphite coating Refereraquoce valar for Hrfk graphite r Reference laquoalac for graphite coanag forma fraction for reference case
greater than that of the graphite coating In addition the Knudsen diffusion coefficient for the graphite coatshying was varied within the same aforementioned range while the diffusion coefficient of the bulk graphite was held constant at its reference value oi 258 X 10 cm 2sec to observe the effects on the poison fraction (cases 2 4 6 81 The previously stated values involving bubble characteristics and mass transfer were held conshystant throughout this series oi cakulalions
The results (Table I J | indicate that Knudsen diffushysion coefficient for the bulk graphite and graphite coalshying at least as low as the reference values (258 X 10 and 258 X 10 cm 1 sec ie case 8) would be reshyquired to meet the 0005 target value I gtr the X e poison fraction A diffusion coefficient of less than 258 X 10 cm 2sec would be required for the bulk graphshyite with no coaling became of its higher porosity If the permeability of the graphite coating did not yield a difshyfusion coefficient equal to that of the reference value such a coating would have little effect ltgtn xenon poisonshying The penalty for not coaling ihe graphite iraquo about OX)I in xenon poison fraction or 001 in breeding ratio if no attempt is nude to decrease the permeability or porosity of ihe base material
It may be noted in case 3 that a slight reduction in the Knudsen diffusion coefficient for ihe bulk graphite is
more effective in reducing the 5 X e poison fraction than a simitar reduction in the Knudsen diffusion coeffishycient for the graphite coating in case 4 In cases 6 and 8 where the permeability of the coating is very low reshyducing the Knudstn diffusion coefficient for the graphshyite coating affects the 5 X e poison fraction much more strongly
1 3 NEUTRON ANALYSIS
H T Kerr D 1_ Reed E J Allen
The neutronic analysis work during this reporting period has involved several tasks aimed at additional description of the neutronic characteristics of an MSBR and the provision of ncutronics information for the fueled in-reactor irradiation experiments
I JI MSIX Studies
Neutronic analysis studies for the reference-design MSBR are in progress in three areas
1 development of a two-dimensional neutronic comshyputational model of the MSBR using the computer code VENTURE and reestablishing the operabiliiy of a reactor optimization code (RODI
2 updating the neutron cross-section data bast used by various computer programs
3 calculation of the rate at which helium wii be proshyduced in the reactor vessel of the MSBR
A neutronic computational model o( Ihe MSBR using the computer code VENshyTURE is being developed VENTURE is a multishydimensional multigroup neutron diffusion computer code The MSBR model will have nine neutron energy groups and the ir-z geometry shown in Fig I J The various zones in the model allow for different core comshypositions and cress-section sets In addition to providing a check oi the design studies made with the ROD code using one-dimensional calculations this model will pershymit explicit evaluation of the nuclear reactivity effects associated with localized core periurbatiuii ltch as limited core voiding Previously such effects were conshyservatively estimated from calculations for an infinite medium of salt and graphite
bullhr pneffcv tuuHaniial reducifcMt in da Kmudm aWuaioa owflfcieat probatory wouhl be accompjaml by reduced po-roaiy
I T B r- ter 0 R Voady and G W ( unnmfham III irTlKf A CoaV mock for Sotriig Htipaup Stummk-ProNtwt Applying the Finite-Difference DiffmkmPieorv Appnaimntkm to Seutron Trmnpprt ORNL-SOamp2 tOvtohet 175raquo
9 II r Ramnann el al HOD A Sudew (md Fuel Cycle ImfSt-Mi Code for CmuUlmtFuel Rewclon ORNL-TM-3JS9
l September I 711
10
79-m7S
-a r
a-7
PERCENT THICKNESS 1 cm) ZONE NO FUEL SALT RADIAL AXIAL
1 CONTROL ROOS 172 2195 2 CORE )A 132 32 a 2195 3 CORE I A 132 500 2195 4 CORE I B 132 1195 2195 5 CORE n A ANO B 370 381 254 bull 9lR)^bV ^ W ^ ^ V v 1000 51 51 7 GRAPHITE REFL 10 7S2 aio bull SALT ANNULUS 1000 oa oa 9 REACTOR VESSEL 51 51
Fk 1 J Tw MMMH^OMI coMf bulltMtoMiMoMorNsm
11
ROD is a computer prccram for nuclear and fuel-cycle analyses of circulating-fuel reactors It consists essenshytially of a neutronks subprogram an equuibrium-conceniration subprogram and an optimization subproshygram Variables uch as breeding ratio fuel composition etc can be optimized with respect to cost
The operational status of the ROD code has been reshyestablished by running a telaquo case for the reference-design IOOO-MW(e) MSBR using the old cross-section data previously generated for the MSR program The test case will be rerun using the ENDFB-IV cross secshytions and any significant differences will be evaluated and reported
Generation of bullposted cross section data The necesshysary descriptive information for the neutronic model for use in the computer code VENTURE has been colshylected and the most recent ENDF1 cross-section data are needed (The neutron cross-section data used for MSBR analysis were originally derived from the GAM-H and ENDFB-I libraries with some ORNL modificashytions1 and no recent updates have been made) The new cross-section data are being obtained exclusively from the ENDFB-IV data Tiles using the AMPX processing system This effort will provide evaluated cross-section data and neutron energy spectra for typical regions of an MSBR and will serve as the data base for subsequent MSBR nuclear analyses The steps involved in this process are
1 Calculate 123-neutron-energy-group cross sections from the ENDFB-IV library The ENDF point data for 39 nuclides are weighted over an assumed energy spectrum to derive mulfigroup cross sections Thermal scattering cross sections are treated at 300 600900 and 1200 K for each nudide
2 Determine contributions to the multgroup cross secshytions from resolved resonances resonance self-shielding is treated for the various fuel configurashytions at 900 K
3 Perform fuel-moderator cell calculations for four geometries to adjust the cross sections for the flux depressions in regions having a high concentration of fuel or moderator (ceD homogenization calculashytions)
10 ENDFB-IV is ihe Evaluated Nuclear Data File-Vcnion IV and is the national reference set of evaluated cross-section data
11 O L SmithPreparation of 123 Group Matter Ctwt Secshytion Library for MSR Calculation ORNL-TM-4066 (March 1973)
12 N M Crane et al AMPX A Modular Code System for Generating Coupled Muttipoup Neutron-Gamma Ubraries from ENDFIB ORNL-TM-3706 J1974)
4 Perform a one-dunemional neutron transport calcushylation of the MSBR core to determine 123-group spectra and collapse the 123-group cross-section set to nine groups for each of the various zones in the model
5 Reorder the nine-group set from nudide ordering to group ordering the cross sections are then ready for use in VENTURE and ROD
The initial processing step is capable of treating nuclides in groups of from 1 to 3 depending upon the amount of data in the ENDFB-IV file for each nuclide This step is now complete for aD the nuclides of interest except 2 T h
Heauaa production bull reactor vessel The helium proshyduction in the reactor vessel for the present reference design and possible alternate designs will be estimated in conjunction with the neutronic modeling of the MSBR (Neutron energy spectra and flux magnitudes in the reactor vessel as obtained from the neutronic modd provide the bass for calculating helium production rates)
Helium is produced in nickel-base alloys primarily from these reactions
raquoNi raquo gt raquoNi raquo gt 5 Fe + 4 He
N i ^ L _ raquo F e laquo H e
degNi gt i 7 F e r 4 H e
The sNi(njt)and the degNi(ija) reactions are induced only by high-energy neutrons whereas the 5Ni(n7raquo and 5 Ni(laquoa) reactions are induced primarily by low-energy neutrons In highly thermalized neutron energy spectra as in the MSBR vessd the two-step reaction 5Ni(n7) $Ni(ffa) is the principal source of helium The 5 Ni cross sections are not wdl known but differshyential measurements are being made by ENDF particishypants1 Abo hdium analyses are available from several irradiated nickd specimens and effective integral cross sections wii be derived from these data for comparisons with the measured cross sections
At presen some cross-section information is available for the NHHJO) reaction Values for the 2200-msec (ix 00253-eV) cross section have been reported as 137 barns 4 and 18 barns It has also been reshyported1 3 that a large resonance occurs at 2039 cV with a total width V of 139 eV From this information a preliminary estimate of the shape and magnitude oi the
13 F C ferry Report to the US Sutiear Data Committee ORNL-TM-4SS5 (April 1975)
14 H M Eibnd el al Hud Sri poundltty 5) I I January 1974
12
cross section can be deduced and 123-group cross secshytions generated
From the Breit-Wigner one-level formula
where
A = constant A = neutron energy
tr = resonance energy (2039 cV) = total width (139 eV)
The constant K can be determined from the value of the cross section at 00253 eV which for this study is assumed to be either 137 or 18 hams Energy-dependent cross sections can be generated and the helium production can then be estimated with te folshylowing equation
-V H eltraquolraquoraquoraquoilaquoraquoJ - bull bull )
X 1 - e x p ( - o e 0 1 o
- [I exp ( -OJ IDI OJ I
where o ( = (17) cross section of s Ni Oj = absorption cross section of s N i Oj = (na) cross section of N i A1 - initial s N i concentration
9 = neutron flux = time
V|| e(0 = helium concentration at time t
IJ2 Analysis of TeGenE-r-raquoiments
Fission rates and tellurium production rates for the fuel pins in the TeCen-l irradiation experiment were reported in the preceding MSR semiannual report The fission rates were estimated by a flux mapping experiment direct flux monitoring of the TeGen-l capshysule and computations analyses The tellurium concenshytrations in the fuel pins were calculated from these fisshysion rates but no estimates for the accuracy of the calculated tellurium concentrations were given in the report
The accuracy of the 2 3 U fission product yield data 1 6 leads to an estimated uncertainty for the yield of tellurium in the TeGen-l capsule of about 135 Assuming that the uncertainty in the estimated fission rates is plusmn15 the uncertainly in the reported tellurium concentrations is about 20
The TeGen-2 experimental capsule is scheduled to be inserted nto the ORR for irradiation in October I97S Flux monitors will be loaded into the capsule prior to the capsules insertion into the ORR After the TeGen-2 capsule is removed from the reactor the monitors will be recovered and their induced activities measured to develop estimates of the tellurium production rates for TeGen-2
14 HIGH-TEMPERATURE DESIGN METHODS
GTYahr
Thermal ratchetttng and creep-fatigue damage are important considerations in the structural design of high-temperature reactor systems Simplified analytical methods in ASME Code Case IS92 (ref 17) and RDT Standard F9-4T (ref 18) permit the assessment of ratchetting and creep-fatigue damage on the basis of elastic-analysis results provided 1 number of restrictive conditions are met Otherwise detailed inelastic analyshyses which are usually quite expensive for the conditions where they are currently necessary are required to show that code requirements are iet Analytical investishygations to extend the range over which simplified ratchshyetting and creep-fatigue rules may be used to show compliance with code requirements are being performed under the ORNL High-Temperature Structural Design Program which is supported in part by the MSRP Modeling procedures for applying the simplified ratchet-ting rules to geometries and loadings prototypic of those encountered in LMFBR component designs are to be identified Then trie conservative applicability of these ratcnetting rules and procedures and of elastic creep-fatigue rules will be demonstrated and placed on a reasonably sound and defensible engineering basis Finally an assessment will be made of the applicability of the simplified design methods to Hasteiloy N under MSBK design conditions and the importance of thermal ratchetling in an MSBR will be determined
S II T Kerr and F J Allen in MSR Program Semiannu Pnrfr Rep Feb A 1975 ORNL-5047pp M 15
16 M F Meek and B F Rider Compilation of Fission Product Yields Vallecilos Suclear Onter 1974 General Elec-ric Company NFDO-I2I54-I (January 26 1974)
17 Code Caw 1592 Interpretations of ASMF Boiler and Prejre Vessel Ctde American Society ltbull( Mechanical Fni-neerv New York 1974
18 KDT Standard F9-4T Requirements flt Construction of Suclear System Components at Elevated Temperatures (Suppleshyment to ASMF Code Cases I$92 1593 1594 1595 and I5VA) September 1974
13
The detailed plans for achieving the stated objectives were given in a previous progress report The basic approach is to perform a relatively small number of carefully planned and coordinated rigorous dastic-plastic-creep ratchetting-type analyses of the geometries illustrated in Fig 14 Each geometry is subjected to the axial bending thermal transient and pressure loadings described in Table 131 of ref 19 Structural problems I and 2 are being analyzed at ORNL using the PLACRE computer program 2 0 while problems 3 and 4 are being analyzed by Atomics International and Comshybustion Engineering respectively using the MARC comshyputer program1 Each inelastic analysis will include a complete code evaluation for accumulated strains and creep-fatigue damage Also ssociated with each inshy
elastic analysis are a number of elastic analyses to proshyvide the input parameters required to apply the various simplified ratchetting rules and procedures and elastic creep-fatigue noes The progress to date on these studies is discussed below
Both Al and CE have encountered difficulties in their three-dimensional inelastic analyses Although consider-
19 J M Comm and G T Yabr in MSR Program Semmtmu Progr Rep Feb 28 1975 ORNL-5047 pp 15-22
20 W K Saitory Fiirte Element Pnfnm Documentashytion High-Tempertnre Sintctmwl DrsnM Methods for LMFBR Components Quart Prop Rep Dec SI 1971 ORNL-TM-3736 p 66
21 MARC-CDC developed by MARC Analysis Research Corporation Providence Rl
-YV^ - NOTOCD CTLMMCM SHELLS TYPE 3 N0ZZLE-1D-9PHQMN
OftNl OWC 75 76S
SMELL
JUNCTION OETAS (TYPES 341
76i0 X ilaquo75 WML
TYPE 2- cnjomctL awns
Q-omdash -T-QlaquoO -Q0
) AT AT I (bull) STEPPED MMLTHKKNESS (k) UNFClaquoM WILL WTH
OFFERENTUL MTOCTTNG
TYPE 4- nomz-m-crurvmcM SHELL flHXMLET NOZZLE)
1 6 0 0 X0375 WALL
-TS IO X 1675 WALL
(O IMFODM VMU MTH (ABULT-M CYUNOEP AXIAL TEMPERATl J VWaATCN
Fij 14 Slnicturai crmfiguraiinns used in the analytical invatqplion of the applicability of simplified nlchetling and crrcp-faligiie rule
14
able effort has gone into developing fmite-elemeni models that are of a size that can be accommodated on presrnt-day computers and into improving the MARC computer program the large 3-D inelastic analyses are proving considerably more expensive to run than had been expected
The experience at AI and CE indicates the importance of developing amplified methods of analysis Three-dimensional inelastic analysis of many realistic comshyponent geometries is too expensive and time consuming at present to be used routinely Although developments in computers and stress analysis programs may bring the cost down in the future it is desirable meanwhile to mminuze die number of inelastic analyses that must be done
141 GrcutarCyundricai Shells
Nine cases of circular cylindrical shells luve been proshyposed for bulllaquo present study Two of the cases involve notched shells The other seven cases involve axial variashytions in temperature pressure andor wall thickness or a bunt-in wall All nine cases were to be analyzed using the ORNL in-house finite-element program PLACRE
A ten-cyde inelastic analysis and a one-cycle elastic analyras have now been completed for all nine cases Both thr inelastic and the elastic results for all nine cases have been completely poKprocessed
Because of modifications to the creep-fatigue damage rules presently under study by the ASME Boiler and Pressure Vessel Code Working Group on CreepFatigue it may be necessary to modify the ORNL postprocessor and repeal some of the postprocessing to keep the present study up to date
142 Nozzle-to-Spherical Sfcenf
After some difficulties the MARC computer code a operational on the IBM computer at the Rockwell Intershynational Western Computing Center and check cases have demonstrated that this code will perform satisfacshytorily
Considerable effort has gone into developing the finite-element model of the nozzle-to-sphcricai shell An isoparametric three-dimensional 20-node brick eleshyment will be used (o model the entire geometry Beshycause of symmetry about the plane of the applied moment only half of the nozzle-to-spherical shel has to be modeled There are raquoix 30deg-wide dements around
bullWork jlt ORNL by W K Sartory Work raquobull Atomics International by Y S Pn
the half-model There are three elements through the wall at the root section of the nozzle and only one element through the wall in both the nozzle and the sphere away from the intersection region
A series of elastic analyses must be done since this is a thermal stress problem in which temperature varies with time Since the moment applied to the nozzL is the only nonaxtsymmetric load the principle of supershyposition will be used to reduce the cost of the elastic analyses A series of axisymmetrk analyses were done to determine the stresses due to the internal pressure and temperature and one three-dimensional analysis was done to determine the stresses due to the moment applied to the nozzle The stresses from the three-dimensional analysis will be added to the stresses from the axisymmetric analyses to obtain the total elastic stresses
The axisymmetric model in the elastic analyses was used to determine what maximum thermal load increshyment may be employed without having to do an excesshysive number of iterations during each increment On this basis the first ryele of the three-dimensional inelastic analysis was divided into 32 increments The first three increments of the three-dimensional inelastic analysis have been completed The computer cost for these three increments was higher than anticipated Efforts wiQ be made to find some way to reduce the cost to an acceptshyable level
14J Nozzte-toCyindeT Intersection
The original concept for the inelastic ratchet ting-type analysis of the nozzle-to-cylinder intersection was to perform two separate analyses (I) a thin-shell analysis of the whole structure ami (2) a detailed three-dimensional solid analysis of the intersection only Disshyplacements and forces to be applied at the boundaries of the three-dimensional solid model of the intersection were to be determined from the shell model at the end of each loading increment The total computer time of the two analyses would be less than that required for the solution of the problem using one model of the complete nozzle-to-cylinder intersection with suffishyciently small elements in the intersection region Howshyever the transfer of the forces and deflections from the shell analysis to the three-dimensional solid analysis was found to be more difficult than anticipated Because the shell element and solid element have differtit displaceshyment functions a special constraint must be imposed on the shell elements at the boundaries of the three-dimensional solid model to assure compatibility This
bullWork at Combustion Engineering by R S Barsoum
15
stiffens the intersection in the shell model When runshyning the initial elastic analyses it was found that small changes in the displacement boundary conditions applied to the solid model would produce large changes in the results of the analysis- From a pragmatic viewshypoint the biggest difficulty with the two-model method is assuring that the correct data are transferred from the shell analysis to the solid analysis at every increment in loading
Due to the above considerations it was decided to do the analysis by using only one model made up of a combination of a reduced integration shell element and a 20-node solid element which are fully compatible with each other
It was necessary to restructure a large portion of the MARC program to perform the inelastic analysis for the
3-D nvdel of the nozzle-to-cylinder intersection This restructuring made a larger core available for the analyshys t The restructuring involved stripping unnccded porshytions of the program putting common space on low-cost storage and eliminating mesh optimization and its correspondence table
The inelastic analysis of the nozzle-to-cylinder intershysection was started The full pressure and nozzle-moment loadings were imposed on the structure which resulted in stresses less than 0936 of the yield stress at 870 K ( I 00degF) When the first increment of thermal load was applied convergence was not obtained because of an error in the computer program which is being corrected
2 Systems and Components Development R H Guymon
21 GASSYSTEMS TECHNOLOGY FACILITY
RHGugtmon GTMays
After a brief shutdown at the beginning of this repottshying period to modify running clearances in the pan water operation of the Gas-Systems Technology Faculty (GSTF) was resumed on March II 1975 with the bypass loop blanked (Fig 21 gt Considerably larger salt-pump shaft oscmatious were encountered than before the labyrinth clearances were increased1 After obtainshying calibration data for the main-loop variable-flow reshystricts and for the salt pump at low flows the ioor was shut down to install the bypass loop variable-flow re-slrictor Water testing was then resumed on April 14 and continued throughout the period
Data for calibration on the bypass loop variable-flow rcstrictor and for the salt pump were obtained At normal pump speed the head-capacity performance of the installed imprDer was v W below the nominal loop design conditions At the nominal liquid flow rate and pressure drop in the main loop the flow rates from the gas outlets of the bubble separator were satisfactory Although loop cavitation (as indicated by wise level) was reduced by replacing the variable-flow restrictors with orifices the amplitude of the salt-pump shaft oscilshylations was not reduced appreciably Prdirmnary infor-
I R H Gaymoa MJ V R Haadty JUSK ABVW Stmt-mm Anjr Rep Feb 291975 ORKL-507pp 23 25
shows that leakage past the salt-pump shaft labyrinth is higher than desirable and attempts wfti be made to reduce thts
Tests under actual operating conditions with water in the loop indicated that the densitometer war be sttsfac-tory for salt operation IVelinwuary information obshytained fiom saturating the loop water with air and then stripping the air by injecting hehum at the bubble genershyator indicated the need for moniioring the oxygen conshycentration in the off-gas from the bunt salt separator in the off-gas from the salt pump in the loop water and perhaps in the water in the pump tank Dtitkuhies were also encountered with the response lime of the oxygen monitors and with the reprodudbiity of their readings
Data on the salt-pump shaft deflections and oscara-tions obtained during the previous period indicated that the running clearances at the labyrinth (fountain flow area I and at the impeuer hub should be increased to prevent contact of the metal surfaces during operashytion with salt (Fig 22) After increasing the clearances water operation was restarted with the bypass loop Hanked off The shaft oscillations were much larger than they had been previously under similar conditions Turbulence or cavitation as indicated by noise was the apparent cause For more flexibility in (Renting condishytions the bypass-loop variable-flow restrictor was inshystalled Loop parameters were then recorded at many
cwmmo
Flaquoj 21 GB4VMWM Facaw
16
17
n$ J J csrf w raquoNVJgt
coaibinaiiotts of lalt-pump speed and settings of the mam loop and hypass4oop variable-flow lestriciorv
Lug-log plots were nude of pressure drops across various sections of the loop as functions of the flow rates through the segments Ssnce the head loss for a fixed resistance is proportional to a fixed power of the fluid velocity the cams should be straight lines unless the character of the resistance changes due to cavitashytion The pSots indicated that cavitation was occurring in the main loo between the inlet to the nauvloop variable-flow restricior f FE-l02A)and the throat oi the bubble generator at flow rates above 320 gpm (1200 liters mm I with the variable-flow resiriclor set at I in (25 mm I above 470 gpm with the variable-flow reslric-tor at 2 in (100 litersmin at 51 mml above 600 gpm with the variable-flow restricior at 3 in (2300 btersmin at 76 mml and above 630 gpm with the variable-flow resthctor at 4 in (2400 litersmin at 102 mml The data were not sufficiently precise to determine whether cavishytation was also occurring in the bypass loop however noise indicated thai it was
Since the loop turbulence andor cavitation as indishycated by noise and the salt-pump shaft escalations were unacceptable at conditions required by the bubble separator design changes were made in the main-loop and bypass-loop flow restrictions By replacing each vamMe-flow restrictor with two or more orifices in series the loop noise level was decreased but there was
little or no decrease in the aaphtwdr- of the a f t oscd-btions
The amptitaae of the shaft ascafetsoas was plotted as a wactiua of salt pump speed at various operating a laquo -dMMis (Fuj 23| At salt-pump speeds less than about 1600 rpm the oscantioas were reasonably smaM and ai any given speed appeared to be unaffected by (11 flow rates between 450 aad 1 0 ) gpmlt 1700 to 4000 liters n a n M 2 ) salt-pump overpre wares between 5 and iSpsig ( I J X 10 to 2D X 10 Pal ( 3 | type of restneuon (variaafc flow restnetors orifices or a coiahmaiion ot these I or 14) flow roate (through the main loop bypass loop or both) At higher speeds the osdaatioa ampit-twe mcreased rapidly with mcieasts in speed and there was mote scatter in the data making it difficult to evalshyuate improvement in cavitation and effects of other variables However at any given speed above about 1700 rpm mcreasmg the flow rate (between 450 and 1050gpm)caused larger oscanuoas
One puaablf explanation for the increased amplitude of the osculations at higher speeds b thai the shaft is approaching its critical vibration frequency and is theiraquo-fore more sensitive to disturbances such as loop turbushylence or carnation The critical speed of this impeller assembly is 220 rpm in an which would indicate a maximum normal operating speed of 1710 rpru using bullhe normal industrial practice ot operating pumps at less than 75^ of critical speed
If the pump shaft osculations were in fact a conshysequence of operation near the critical speed ot the rotating assembly two obvious alternatives were availshyable to reduce the amplitude of the oscuHaiions
1 further reduction of the loop disturbances to minishymize the driving forces that cause oscillation
2 operation at lower speeds to reduce the osolatorv response to disturbances
The first alternative was rejected because it would have required extensive modification of the loop and it was difficult to guarantee that all sources of such disturbshyances could be reduced to satisfactory levels Design cakidaiiofls showed that the desired flow and head (3800 litersmin at 3 0 3 m or 1000 gpm at 100 f u could be obtained by replacing the present 11 Virt-diam (2ftgtnun) impeter with a l3-tn-dam (330-mail unit and operating it at 1500 rpm A larger impeller is being machined from an available HastcHoy N rough casting Since the larger impeller will be somewhat heavier than the original one it win cause a reduction in the critical speed of the rotating assembly The estimated critical speed with the new impeller is 2000 rpm which makes the operating speed 757 of the critical speed
18
n-va
I
bull
bull 4SO-C4V laquo bull TOTM run
bull bull80-KM9 laquo bull TOTH FLOW bull t
bull bull
bull
bull bull bull bull bull bull
bull bull bull bull m bull m bull
r- i bull gt
bull bull bull bull - bull jr bullbull r laquo bull 1
bull laquooo ooo rsoo i4oo CMO
SALT n w SPCEO t fraquo) lt7oo laquoaoo
Flaquo2J GSTFpanpAtfia
At a few off-design conditions during some of the bter runs the pump shaft deflection records showed random spikes in one direction superimposed on the relatively uniform oscillations described earlier These occurred with higher than normal flow rates in the main loop or at reduced system overpressure Since eidter increasing the overpressure or injecting gas at the bubble generator reduced or eliminated these random oscillashytions it was concluded that they were a consequence of cavitation at the bubble generator Such cavitation and the attendant oscillations are not expected to occur at normal operating conditions
212 Sak-Twnw f i i f i inmdash u DMa and CaKbration of the Variable-Flow Ratricton
The original design of the CSTF provided for varying the salt-pump speed andor changing the variable-flow restrict or settings to obtain different flow rates or presshy
sures needed for future experiments However instrushymentation will not be provided for measuring the bypass-loop flow rate during salt operation and only urn salt pressure measuring devices will be installed I at the salt-pump discharge and at the bubble-separator disshycharge) Also since the salt pump was modified and has a mismatched impeller-volute combination no perforshymance data were available Therefore extra pressure indicators were installed for the water tests and loop pressure profiles were obtained at various pump speeds flow rales and variable-flow restricior settings to evalushyate the pump peiformance
The calibration of the main-loop variaMe-flow restric-tor and of the salt pump at low flow rales was straightshyforward since with the bypass loop blanked off the total pump flow was measured directly by the main-loop vert tun However once the bypass-loop variable-flow restrictor was installed the calibration of it and
19
the pump was complicated Hie main-loop variable-flow restriciof was closed and the bypass-loop variable-flow rest net or was calibrated at low flow laies using the pump calibration curves established before it was inshystalled The mam-loop variable-flow restrictor was then opened to various settings and the pump calibration curves were extended by adding the measured flow through the mam loop to the flow through the bypass loop taken from the bypass-loop variable-flow reslnctor calibration curves Then using these extended head-capaciiy curves for the pump it was possible to extend the calibration curves to higher flows
The pump calibration curves (Fig 241 indicate that at 1770 rpm the pump flow rate wiB be 970 gpm 13700 litersmm) at 100 ft 1305 ml of head The ongnul design called for 500 gpm (1900 litersmmgt through each loop however the bypass flow rate can be reduced to 470 gpm (1800 liters mm) without compromtsng any of the objectives
To determine the main-loop variable-flow restrictor selling for normal operation with a flow rale of 500 gpm in the mam loop plots were made of the pump head vs flow for several settings of the flew restrict or From these a curve was made of pump head at 500 gpm (1900 litersmm) vs settings (Fig 25) A 185-m (47-mm) setting wril give the desired head of 100 ft (305 m) at 500 gpm
m - K B i
lt M M laquolaquo IFC-I02M SCTTWG FOraquo 300 laquo bull Zr-MSS laquo bull C-laquo4AJ
SpoundTTlaquoVS FOM0laquoB ^ Str-MSS vlaquoMFt-laquoolaquoi
si TlaquoK ran 47olaquopraquo
1 2 3 4 VMIASLC FLOS EST^CTO SCTTI
s
FraquoZ5
bull40 bull n-vw
C O shy
CO
l
CO bull
40 1
20 f
o 200 400 M O n o ltooo woo FUMIlaquoOTI
Fit- bullbull Hcai capacity curves for oV GSTF y mdash gt bull
The bypass variable-flow reslnctor settings were detershymined similarly 7 -I found to be 1-85 in (47 mm) at 500 gpm (lltHXgt liters mm) or 170 in (43 mm) at 470 gpm (IK00 liter v mm)
21 J Satt-Pmnp Fountain Flow
The GSTF salt pump is a centrifugal sump pump having an impeller which rotates in a volute section which in turn is located in a pump bowl The clearance between the impeller and the volute assembly at the pump inlet allows leakage from the discharge directly (o the pump suction (see Fig 22) A second bypass flow called the fountain flow escapes through the clearances between the impeller shaft and the volute assembly This bypass stream flows into the pump bowl circulates downward and reenters the main stream at the pump suction Due to the large liquid holdup and large surface area in the pump bowl significant gas-liquid mass transshyfer can occur in the fountain flow stream and herefore its flow rale is important in analyzing mas transfer processes in the loop Since the fountain Pow is not measured directly a method using mass balances on
20
measured gas flows was developed to determute thn flow rale
A lump J-parameter mcjel of the GSTF was used to develop equations Iron which an express lor ike rounfam flow was dented The system model contain two major regions the pump bowl and the primary loop Imnn and bypass segmental cutmstmg ai a fas seciion and a liquid section tach section was assumed to be perfectly mued The three enteral time-dependent equations lor a specific p s m i gas mixture are given m Tabic 21 representing gas mas balances for the pumrbowi gas section the pump-bowl tinwd section and the primary-loop f seciwn Icuculating oidsraquo
These were simplified by applying the folowmg
1 There is no gas carry-under in the pump bowl which implies that Ugt the efficiency for separation of bobshybles from the fountain flow Ut a unity and Ft -Ffi bull | + Afs-gthe bwbWe surface area m the pump howl M I the void fraction in the pump bowl frgtngt and the concentration of gas m the pump bowl (Clt I are nonappbcable or zero
2 Mass transfer equtJibnurn nasts in the primary loop which implies that the mass transfer term - j(C 4 -KRTCi )a zero
3 Steady-stale conditions exist making all time derivashytives zero
4 Ff = 0 since there was no gas purge flow during the experiments
Therefore Eq (3) Table 21 reduces to
FB FfL ltlaquo = 0 Ml Solving f o r +
By adding Eqs (1) and (2) Table 21 and simplifying
FjyenLCgtFfi +1C+FBSCX
FC Ff( rtC1FBSCJ=0 16)
By substituting Eq (5) into Eq (6) Ff may be exshypressed in terms of a quadratic equation
ltC C 2 I F bull KQi Fbdquo FBSKCt C 2 )
FgCt FCtFf
QttlF8SltC C raquo F C | 0 (7gt
Equation (7) is a general solution for the fountain flow which depends upon the gas concentrations in
each ol the three sections of the model It it is assumed that man transfer equAbmm exists at the galaquoltiugtd interlace in the pump jowl the gas conceniciuon in the pump bowl liquid | ( I is relaied to the correspondmg concentration m the pump bowl gas section tCt I raquoy Henrys law If only one gas rs involved (eg heliumK C toNows directly from the pump buwl overpressure Further since mass transfer equuawium was assumed for the primary loop ihe gas ctmcentralion m the kiop liquid (for a smgk gas) ioifews from the loop average pressure and Henry s law Thus the foil am ikm magt be evahsalaquoed from fcq |7raquo using orker known liquid flow rates and measurable gas flow rales into and owl ol the system If no mass transfer is assumed to occm~ at the gas liquid mterface m the pump bowl thr gas conshycentration m the hqmd leaving the pump bowl is the same as thai in the cmtiiug liquid lue O = C I and Eq(7i reduces to
^=IFgCyFCi I ^
Since the rate oi mass transfer m the pump bond is neither minute nor zero Eq I 7 I ni l give a low indftca-tion and Eq (X| laquo i give a high indication of the founshytain flow rate The deviation from the actual fountain flow rate win depend on how much mass transfer actushyally occurs m any experimeni If the loop void fraction is increased (by increasing the gas input rate I the conshytribution of mass transfer across the gas-liquid interface to ihe flow rate of gas laquo-ji of the pump bowl wif be reduced relative to the bubble contribution Therefore a pkn of the calculated iountam flow vs Ihe reciprocal of the gas input rate at several different conditions should give the actual fountain flow rale when extrashypolated to zero (infinite gas flow rate) usmg either Eq (7raquoor(8gt
The preceding equations and approach were used to calculate the fountain How for the GSTF pump Results from ihe plot indicated thai the curves generated were not defined wen enough to provide accurately the reshyquired extrapolations The range of fountain flows at the highest gas input rate at which data were obtained was 100 to 200 gpm (30 to 760 litersmmraquo
Even the lower estimated value for the fountain flow may excessively complicate future mass transfer experishyments so efforts will be made to reduce this flow Since ihe labyrinth clearances cannot be reduced without incurring meial-io-metal contact between the pump shaft and the volute hack vanes will be installed on the lop of ihe impeller lo minimize the differential pressure which drives the fountain flow
Iihfc 21 (iiimiuhaUmimpjallnntfitf timtpulalfcinmiMHof (iVI
KllO til illlll|tkltil |tl pill|K lllllilllis scpHlUil IMIlaquo IfMIKU nl t in nl oil Kii iiivkiilnl ill llnw ill bull limn liiiiiilini bull iliraquoraquonluil |Mgt lt mw ^JVIIHIII pinup linlaquol III yis gt|iui Him lH|iil(lniv inliHir pump Imwl
lltpi l n I lt f lt bull bull bull laquo lt laquo laquo laquo raquo laquo iff
Kllgt ill tlltllllr lllgtMi|vraquoll bullMl itlsMllVCll IV 11111 lllllslll 111111 ILIIKUM lllraquoraquolaquogtlVlaquol |l ni ittN iimMim |HiMiii in pii-witi m ni ltlin|tiil ut ilimlraquoilaquol pivwiii in iligtlaquo ilhvilvcilin liKnimiiK liuinlim llutt limn IMlaquo A I raquo laquo IM in Iniltlil trnm pump innn| Iiwl ln|iml illaquo lnihlltKIIIIIII hi|iiiil initligt in |iiini|lt linul biwl in lu|i
IH (11 Imlt vill
laquoltplllln| Kpiitiui I bull(raquo bull raquo I US gt laquo A K U i IHIl gt raquobull raquol IyjM
raquo i
KiMniil ihmvn iluw nl ilntt nl hiililiUv n u n luinl t i IIIIIIIIIOMII iliMmUinl raquoM ImhNiivinuwit bull I Civ linnillnH igtilaquo in Itmi pump Imwl I IIISSIIMII IIUIIIIIH ill lninliin In IMIMIII
III limp mill IHIIIIIU bull Inlnnp bull (ligt bull IliMJo llim llnlaquo w p j u l m llflltLllnl l l l l n i i | i
l i p u i m i I bulllaquo bull gt laquo l laquo IKH gtill M raquo O 1 raquo
22
214 The void fraction of the liquid after it leaves the I
Me separator n u n be known in ordrr to evaluate the bubble separator efficiency Densitometer mstrumenta-IWB (unwf a digital voltmeter for readout was mrtalrd at the loop and tesu were uumr using 0 3 0 0 ( 1 1 X 0 z dnsecl i raquo T a ece The effccu of void fraction were shambled by inserting pontic sheets 3 and 6 nms |0J07copy and 0152 mmi thick between the
detector and by using the mrtamc shim side m m k n steel cahVratioa plates 10 to 250
mis (0254 to 6 J 5 mm) thick which were designed for rhraquo purpose
The nail cncounteied dming dealupmtnt testing uras stal peestnt The hourly drift would be equivalent to a
efficiency of shorn 10 a h operation (assuming a void fraction of 0J
at the - c ^^hMe separator) Thus short-term tesraquoi wnl be required to ntmnunt the bdbbk jcparaior efficiencies
bullused on densitometer readings the bubble-separator efficiency was greater than 98 at various operating conauuons with water whkh it shghtty predtcted
Ft Ft
Fraquos
Ft
A -
of liquid gar interface m pump bowl bubble surface area in puop bowl bubble surface area in loop gas concentration in pump bowl gas space gas concentration sn pumn bowl hauid gas concentration in the loop bubbles gas concentration in loop liquid gts concentration m pump bowl bubbles gas concentration in gas purge entering the pump bowl gas space flow of total off-fas from pump bowl gas fltow rate to bubble generator nqiad flow from bubble separator via the bum salt separator to the pump bowl (assume no bubshybles) fountain flow (liquid and buboto) flow of gas purge into pump bowl gas space flow of liquid and bubbles from pwnp bowl to loop mass transfer coefficient for gas dissolved in pump bowl liquid to gas space in pump bowl mass transfer coefficient for gas dissolved u pump bowl liquid to bubbles in pump bowl mass transfer coefficient for dissolved gas in loop liquid lo bubbles in loop liquid
K Henrys lr~ (solubility) coefficient Q flow of bruid and buttles to bubble separator A universal gas constant r temperature
V laquo total gas volume in pump bowl V2 mlumt of wquuland bubbles m pump bowl VL = volume of drcubnutt liquid and bubbles i
loop c ( bubble separator efficiency tf efficiency for separation of bubbles from founshy
tain Aow bull t z void fraction in loop fluid
ltbullgt void fraction m pump bowl flutd
2-2 COOLAKt-SALTnamOUXX FACaUTYKSfF)
A N Sunt
Modifications to the sak coM trap (SCT) were com 1 and the loop was started up on March 14 and operated for 1279 hr to check the effcetrve-|975
of the sail titer to obtain data on salt different operating condrtmws
off-gas sample dau m preparation Work was completed on design
and checkout of the trita the tritium test
generation rates and to obtain salt and for the tritium tests fabrication addition system started At the end of the report period two tritium additions had been completed aad plans were being made for additional tririum addition tests as well as tests designed to examine how the tritium behavior is affected by the infection of steam into the sail
221 Laap Opossum
The SCT flow tnes were disconnected from the sysshytem and the loop was started up on March I 1975 The loop operated continuously until May 6 1975 when it was shut down to permit insinuation of otnp-ment in the containment enclosure for the tritium tests The loop was started again on June 271975 and it was saB in operation at the end of the report period when more than 2500 hr of operating tune had been togged without pHajgmg in the off-gas tine This is convincing evidence that the salt nust filter has been effective since the off-gas Ime had piuggct after only 240 hr of operashytion before the nasi fdier was instated
The loop is operating at a pump speed of 1790 rpm (estimated salt flow rate 54 literssec) and a pump bowl
2 A N San MS 2$ 1975 OKNL-50t7t 25
J IMttI
Avar Rrp Frb
23
praquo overpressure ol 2hi X IU5 Pa (20G0 mm 1 absi The pump bowl oit-^u flow which consuls ui helium coniammg a tew percent of BF prm trace quantities ol condenuMe material is about 2 litervmm iSTPl- The BF i concentration ltraquoi the oil-gas rraquo a tuncnon ol the bull1-1 partial pressure in the tail which in lurn raquo a strong unction in the tail lemprfaiuie txcept Im short period raquoi lime when special tests required a different retime the valt circulating tempetature haraquo beet mauv lamcd ai 535 lo 540 ( at which pomt the BF concenshytration in she oli-ga dream is about 25r by volume The loop otf-garaquo stream emepf tor a 100-cm1 turn wmpk gti ream iv paued through a 72(cuht iraptdry ice alcohol bath | Material which is a dtn while toiid ai itap temperature and a dirty brawn ilmd upon warmshying to room temperaiuie and which is rich m tnimm (about 1(1 nO el continue ilaquogt collect m the cold trap at a rale laquogtt I igt lOngcm (STPlotKff-ga Thnmaie-iial rraquo believed lo be a variable mixture who- compos-lion depends on the relative partial pressures ol BF HFand H Ooser the salt (see Sect 41i
A ol 000 on Auguvt 31 Ilaquo75 the bullop had accushymulated 3073 hr ol sail circulating tune smce being reactivated in Decembei |raquo74
222 Salt Mat Test
Bemeen March 25 Ilaquoraquo75and April 24 Iraquo75 a series ot icsigt wj run lo determine ihe concent ration ot wit
t m the off-fas stream as a runctwu ot a l t tempera-lure aad BF flow for each lest the loop operating coadaioas were set at the desired values ami the off-fas stream was shunted through a metamc 5- to deg-m (iter whKh was inserted mto the ait-sample access nozzle on the pump howl The sal mat concentration was calcushylated usmg the fan m weight of the filler aad the total flow sf fas A total of tea teas were earned out The test tune was nnrmatty about 12 to 15 hi but in two cases it was shortened tc about 3 hr because at the buildup ot a high-preawiie drop acroa the fdter Pump bowl pressure was 2Jb7 X 10 Pa and total off-gas flow was 1 litervmm (STP| When BF was added to the helium entering the pump bowl the BF flow was ad-msted raquo (bat the BF partial pressure m the mcomuig gas was the same as tFe calculated psttial pressure of the BF over the salt asswmng the eutectic mixture ot NaBFlaquo acd aF The salt drcutatiag temperature was controlled at either 535 or 620degC The observed conshycern rations ol mtst m the off-gas (Table 22) ranged Irom MOO ng on ai the loner temperature ibdquo as mgh agt 500 ng cm 1 al the higher temperature At the lower temperature where the expected partial pressure of BF in the sail raquoalaquo low the addition of BF with the cover gas was ineffective m reducing the amount ot ~ist in the off-gas At the hajtter temperature Hugher BF
P 27
23 CSTTi 175
VJ St Bt rcmrvrjrurr ijpampr rtlaquoraquo
t gt prepare iraquom mmSTPgt bull mm tic
raquo
Sjir imit iltgtikrgturjiraquogtn IIK Jr o n laquorr if-jtni
2fraquo |ltraquoS
raquo 25laquogt
5
Ifco
Klt-tft Zgt
5 5-532
bulltnrrlaquoflr 4Vlt
H
ion
Avrufr laquoi
11 i KX
KvrisfX 15
Vtumi^r Ih niKviic bull HtipgtltJium
24
partial pressure in the salt) a significant reduction was observed in the mist concentration when i lFj was added with the cover gas However it was not reduced to as low a value as at the lower temperature These results whie not completely definitive suggest that bull F evolution from the salt may no be the only mrst-producing mechanism in the pump tank that is simple mechanical agitation of the salt in the pomp bowl may abo produce some mist In addition no data were obshytained with excess BFj concentrations m the cowr gas Since the mstaflatioR of the salt-rust iHter in the off gas line was effective in eiumnating the operational probshylems in the CSTF caused K v the mist further investigashytions of methods to lirnii or control the mist have been deferred m favor of experiments to study tritium beshyhavior in the system
The decision to use tritium rather than deuterium a a test gas4 in the CSTF necessitated additional design effort and a somewhat more elaborate test setup in order to satisfy apubcaMe radiation safety require-meats A conceptual design was prepared for he tritium addition system and a preimnnary radiation safety analysis was performed for the proposed test Engineershy
ing design procurement fabrication and msiaBauon of the tritium addition system were completed by the third week m June 1975- The addition tube and the addition procedure for tritium are essenttaly the same as those devised for the addition of deuterium The rwer tube of the addition assembly is pressurized with hydr-jgen contanung a small amount of tritium and the gas is avowed to diffuse through the Hastefloy N tube which loom the lower end of the addition tube and which is immersed in the flowing salt stream (see Fig 2oraquo The HasteSoy N lube is 120 mm long by 127 mm in OD by 106 mm m ID and provision p made to fasten metanurped specimens to the upstream faje The portion of the addition tube inunedntely adjacent to the HasteRoy N section is surrounded by an evacushyated annuius monitored to check for extraneous tritium leakage The hydrogen-tritium mixture is passed through a purifier (M-Ag tube) to remove impurities such u O Ngt and H G which might interfere with the permeation process The probe volume ~p (infecshytion tube plus adjacent tubing) and a calmrated refershyence volume are interconnected and pressurized with the H - T mixture at the start of the test The two volumes are then isolated trom each other whne the addition rs in progress At the end of the addition
-Owe 75-T2CW
TRITIUM TRANSFER CYLMOER
4 0 0 C
sect laquo r 2^
1 SAMPLE
VACUUM ltS)
ampQ- ]
HYDROGEN
VACUUM ANNULUS
INJECTION TU8E
|StT2
35-C
lOO-C
FLOW 532laquoCi
Fig 2 T w mdash aUthnm ygtw far CiSTF
25
period the difference m pressure between p and V is recorded then the two volumes are equdibrated and the final equilibrium pressure is recorded The initial and fwal pressures ir lppx and pz respectively the foul equilibrium pressure p and the known volume and temperature ot lgt are then used to calculate the amount ot fas which pernxated the addition probe according to the equation
laquogt PiPi Pi V bdquo = _ x ^ try Pzraquo PT
where n is (rK number oi moles ltgti gas transferred R is the molar gas constant Tr is the reference volume temshyperature and the other symbols are as previously deshyfined
During the addition the amount oi extraneous leakshyage i calculated from pressure rise measurements in the evacuated annulus and this quantity is subtracted trom n to obtain the net amount oi gas iransierred into ihe salt The tntium content ot the hydrogen-tritium mixshyture is determined by mass spectrometer anaksu and Ihe net amount ot added tritium is then caicuiated
Tritium land hydrogen) which enters the salt stream rs assumed either to rematR in the sail laquo iraquo leave ihe sail by one ot two paths eiiher hy permeation through the walls ltgtl ihe loop piping or by irartsler to the gas phase in ihe pump howl or in the sail monitoring vessel iSMYl and leaving the loop raquoih the oii-gas stream During and ailer ar addition the tritium conieni ot the sail is monshyitored b lakmg samples raquot salt trom ie sail pool n ihe pump bowl or in ihe SMV and ihe irmum content oi ihe oil-gas stream ts rrhMMored hv takiru sampics from he oii-gas line ai a point ahoul I m downstream bullgt ihe rramp bowl The oil-gas sample stream is pasted first through a water trap to collect chemicaiiy ^gtmh-neltl I water-slaquo M unlet tmium and then through an oxidizing atmosphere to convert eiemeniai iriiium io iniiaied water raquohkh is c-iliecled in a seciid irap The tritium conieni oi the salt samples and ltraquoi hoih ihlt oil-gas samples are determined hy a scintillation cHinimg techshynique During the iniiul tritium addition experiments no provision was made IlaquoH measuring loop wait petnva-lion so lhat ihe tritium lost hy this mechanism is assumed |o he Ihe ditferenlaquoe hefwven the arnouni of Iniiiim aided and ihe sum oi the quantities w-hich ieave in ihe oii-gas stream and which remain in the sail
firing the March 14 Igt~v | 4 y |ltrgt bdquopei almg period a number of sail and off-gas samples were taken fo obtain baseline raquoaJues |o minim concenira-lion and lo shake down and evaluate the sampling tech-ii-ities During sluiidown oi lthe CSTI- in Magt and June
Iraquo75 the intium addunn probe was msiaUed in the survediance-spei-onen access tube and the final installashytion work was done on the tnUum addition system A stainless steel valve (HV-255AI and some stainless steel tubing which were part of the original off-gas sample-line installation were removed and replaced with a Mood valve and Hastelloy N tubing because it was ieii that the Monti and HasteUoy N would be less likely to react with the off-gas sample stream Two 2-5-cm-diam X 45-cm-long KastelkA N lubes were filled with sail from the dram tank and set aside as representative samples oi the salt as it existed prior to the start oi the tntium tesis-
On June Z~ I~5 the mop was filled and salt cirvuia-tion was resumed Several additions o i hydrogen raquoere made to check out the operation of the addition system aid to obtan data on permtaiior rates A loul or bull J cm M f l oi hydrogen was added in ihese rest and the last addition lt raquol an STPraquo was made -gtn July Jfs Ilaquoraquo~5 with ihe addition tube pressuried to I_gt~ X It) Pa the measured permeation rale was about laquo cm hi ipared with a predicted value i raquo era hr The Iirsl addition o iriiium was made on July l~ i _ 5 and a second addition with CiHlditmns essenziaili he same as iraquor the fust additnm was made August 5 1 _ 5 In each case sail and oii-gas samples were taken during ihe tritium ad Inigtft lahoui 10 hri and or atgtraquou 2 weeks afterward until sample resuiis indicated Tf at the intium levels had returned io iheu pretest values or had Mahihed Oaia lot calculatufi o ch-e amount o addej ps are sin win in Tabic _ A maihemaiica analysis and discuss of ihe tampie results are presented in Se^ i i
TaMr 2J Jtwtmm JMIIPO 4U far CSTI rnf
f rr runilv-r 1 i lraquojrc ~ ~y s r
ti4iilaquon vijrTrJ i raquo bullxt ltMiri-n erxteJ - gt lt o -gti VMiTfcltn -aw bullgt t N bull Im-ijS p-i-uir^ TjiTa i s j r bull bull bull 1 raquoUl prcraquoMraquorf p~ ltti bullraquo laquo bull r - t |utftt -nm p-riu-r r f^i a bull laquobull 1 bull 1 r v-jirrlt- m i i gt i i
fr Tcmr^r 4u-r k bull laquo lt l l bullbull ltrr gt rv-Tltjriraquor - r m -raquo raquo i 1 bull bull raquolt--laquo-f i e j l -j -lt- rn bullbulllt raquo raquo 14
i--tTWjTl-raquon - J 7T1 bull - raquo bull bull gt |TTti-n -raquonltf n TilaquoT in nisfi ii bull bull bull
ra^ pr^i l--l i m u M e i laquo m i it it X bull bull
1 bullbull J irmm j dea bull ml 11 raquolt bull
26
2 J FORCEftCONVECTlON LOOPS
W R Huntley M D Silverman H fc Robertson
The Forced-Convection Corrosion Loop Program is part of the effort to develop a satisfactory structural alloy for molten-salt reactors Corrosion loop MSR-FCL-2b is operating with reference fuel salt at typical MSBR velocities and temperature gradients to evaluate the corrosion and mass transfer o( standard Kistelloy N Addition of tellurium to the salt in MSR-FCL-2b i olanned after baseline corrosion data ire obtained in me absence of tellurium At this time the loop has operated approximately 3000 hr at design ST conditions with the expected low corrosion rates
Two additional corrosion loop facilities designated -ISR-FCL 3 and MSR-FCL4 are being constructed They arc being fabricated of 2T titanium-modified Hastelloy N alloy which is expected to be more represhysentative of the final material of construction for an MSBR than standard Hastelloy N
2 JI Operation of MSR-FCL-2b
Loop FCL-2b was operated continuously for about 3000 hr from February to June lraquo75 unuer design ST (565degC minimum 70SdegC maximum)conditions During this period standard Hastelloy N corrosion specimens installed in the loop in January 1975 were exposed to circulating fuel salt at three different temperatures (565 635 and 705degC) As expected corrosion rates were low the highest value was 01 mil year Ojimyear) at the highest temperature station
Salt samples taken at intervals have been analyzed for major constituents metallic impurities and oxygen (Table 24) Except for an occasional high value for oxygen or iron the analyses are relatively consistent and indicate that the observed corrosion processes have had very little effect on the concentrations of the various species present in the fuel salt Analytical probe readings for the VIU ratio indicative of the redox condition of the salt have been taken on a weekly basis This ratio which wraquo about 7 X I0 3 at the beginning of the corrosion run rapidly dropped to about I X | 0 3
after the first 24 hr of operation The ratio then gradushyally fell to A I X I0 1 by the end of March CVI500 hr elapsed time) and it has remained at that level during the latter part of the operation
After the corrosion specimens were removed for the 3000-hr weight-change measurements preparations wei nude for obtaining htat transfer data on the Li-Be-Th-U fuel salt (717-16-12-93 mole ) At this
time a Calrod electric tubular heater failure was disshycovered on the pipe line (i 27-mm-OD X 11-aim-wall) which runs from metallurgical station No 3 to the inlet of cooler No I After removing the thermal insulation about 10 to 20 cm 3 of salt was found on the loop piping and the bumed-out heater Grainy material was present on the heater sheath at three locations directly opposite peeled-off sections of oxide layer on the Hastelloy N piping A small crack (A 5 mm long) was found on a tubing bend directly under the failed heater Whether the heater arced causing the piping to fail or whether the salt leak from the loop caused the healer burnout is uncertain at this time Examination of specishymens from these regions is continuing
The fuel salt was drained from the loop into the fill-and-drain tank after the leak was discovered Analytical results on a sample taken from the tank indicated that no obvious contamination of the fuel salt had occurred A new section oi tradeping was installed (approximately 24 m from metallurgical station No 3 to the inlet to cooler No I) During the shutdown several defective thermocouples and two defective dam-shell electric heaters were replaced Ball valves were refurbished numerous small repairs were made and instruments were recalibrated After the thermal insulation had heen replaced baseline heat loss measurements were made with no salt in the loop in preparation for taking heat transfer data The loop was ready for refilling at the end of aly approximately four weeks after the salt leak was discovered After filling the loop heat transfer measurements were obtained with flowing salt The ALPHA pump speed was varied from 1000 to 4600 rpm resulting in salt flows of approximately 27 to 16 litersmin which correspond to Reynolds numbers that vary from 1600 to 14000 The lower limit for salt flow was set to prevent freezing and the upper limit was dictated by the power required foi driving the pump At the lowest flow rate unusual wall temperature profiles were noted which probably were caused by entrance conditions and transitional flow effects The heat transshyfer measurements were completed near the end of this reporting period and analysis of the data is in progress
The stringers containing the Hastelloy N corrosion specimens were reinserted in the loop and ST operashytion (S65degC minimum 705degC maximum) was resumed in order to complete the originally planned 4000-hr corshyrosion run If no unusual corrosion behavior is encounshytered in the next 1000 hr of operation nickel fluoride (NiFj) additions will be made to the loop in order to raise the oxidation potential of the salt to a level correshysponding to a U^U3 ratio of about I0 3 and a new set of corrosion specimens will be exposed
27
raw t u si tioalaquolaquofcUF-laquofF -ThF-UFlaquo
i-im
Sanpfe Mo
Date impkd (197$)
Total hoars of a i l
arcabboa bullhel saatptcd
Major coapoMMs TIJCC ameiub Notes
Sanpfe Mo
Date impkd (197$)
Total hoars of a i l
arcabboa bullhel saatptcd Li Be Tb U F Fe a f t O C S
lb 1-17 0 78 221 43-2 I I I 467 101 40 23 lt50 I I 99 Flash salt 2b 1-23 48 60 42 52 3b 128 0 799 174 430 an 463 75 70 15 125 29 4 3 New sail 4b 2-11 177 137 63 60 75 Sb 2 18 355 154 64 68 45 6b 2-24 498 98 63 28 48 7b 3-3 676 7 8 236 4 2 J 105 463 147 67 35 45 23 17 bullb 3-25 1146 7UI 255 430 104 458 256 59 57 lt2S 14 9 9b 4 16 1647 816 229 432 097 452 $ 70 30 20 78 15
10b 5-12 2197 829 264 430 103 455 62 85 30 60 l i b 6 4 238 823 225 427 100 445 30 70 25 140 12b 6-23 3173 820 208 433 104 451 35 75 25 152 13b 7-3 3177 830 218 430 10 452 70 80 40 30 FaVaaa-dran
oak Mb 8-7 3246 728 203 454) 100 450 45 85 70 58
7|7-16-i2-03 mole bull
232 Desia Mid CoastnKtkm of FCL-3 raquossrfFCL4
The design work for FCL-3 and FCL-4 was essentially completed any changes or revisions which occur during construction of FCL-3 will also be made on FCL-4
The piping support frame for FCL-3 was installed and installation of electrical equipment is proceeding- Conshyduit lines have been fin from the variable-speed motor-generator set on the ground floor up to the electrical rack installed on the experiment floor and a sizable
number of transformers starters switches etc have been installed The instrument panel cabinets have been positioned and cable trays are now being installed Fabrication of two ALPHA-pump rotary elements and two pump bowls is 90 complete A large number of completed items for both loops (eg dump tanks auxilshyiary pump tanks cooler housings blower-duct assemshyblies electric drive motors purge gas cabinets etc-) are on hand awaiting installation Fabrication of the titanium-modified IrasteHoy N tubing for the salt piping of the loop is in progress
Pan 2 Chemistry
L M Ferris
Chemical research and devdopmen rdated to the design and ultima^ operation oraquo MSBKs are itill conshycentrated on fuel- and coolant-salt chemistry and the devdopment of analytical methods tV-r use in these systems-
Studies of the chemistry of tellurium in fuel salt have continued to aid in elucidating the role of this dement in the interranular cracking of Hascdioy N and related alloys An important initial phase of this work involves ihe preparation of the pure tellurides Li Te and LiTe3
for use in solubility measurements loop experiments clectroanaiytical studies and studies of tellurium redox behavior in molten salts Technique for preparing these idlurides have been developed and experimental quanshytities have been prepared Spectroscopic studies of tdlu-rium chemisfy in m-jlten salts and of the equilibrium H(ggt + UF 4 |d) = UKj(d) + HF(ggt have also been
initiated In work using molten chloride solvents at Lust tvo light-absorbing tellurium species have beei shown in be present These species are as yet unidentishyfied but have compositions in the range Li2Te to LiTe4 Preliminary values of the quotients for the above equilibrium have been obtained using LiBeF4 as the solvent These values are in reasonable agreement with those obtained previously by other workers
A packed-bed electrode of glassy carbon spheres was constructed calibrated with Cd1 ions and used in experiments with Hi1 ions in LiCI-KCI eutectic It was concluded that this electrode was prototypic of orie (hat could be used for the electroanalysis or electrolytic removal of bismuth oxide and other species in MSBR fuel salt Preliminary experiments were also conducted lo evaluate some questions relating raquoo the mixing of fuel
and coolant salts The results suggest ihat or mixing small amounts oV coolant salt with large amounts of fuel sal the rate of evolution of BFj gas will not be intolershyably high and that somj oxide can be present in the coolant salt without effecting precipitation of L0 or ThO - Lattice enthalpies of first-row transition metal fluorider were calculated to provide a theoretical basis for evaluating thermochemical data gtr svructural-metal fluorides
Work on several aspects of coolani-sait chemistry has continued Analyses of condensates from the Coolant-Salt Technology Facility (CSTF) indicate that the vapor above (he salt is a mixture of simple gases such as BFj HF and H 0 rather than a single molecular compound Tritium concentrates in the condensates by about a factor of 10 s relative to the salt Studies of the system NaF-NaBF 4-B 0 at 400 to 600degC show that at least two oxygen-containing species aie present in typical coolant salt One species is Na B F 6 0 j while the other has not yet belaquon identified
The development of analytical methods for both fuel and coolant salt was also continued An in-line voltam-metric method was used to monitor U^U 1 ratios in two thermal-convection and one forced-circulation loops Two additions of tritium were made at the CSTF The salt in the loop did significantly retain tritium and the tritium ultimately appeared in the off-gas Work was begun on using various electrodes for determining iron in MSBR fuel salt Previous work had been conducted with solvents that did not contain thorium Preliminary voltammetric experiments were conducted to identify soluble electroactive tellurium species in MSBR fuel salt
28
3L Fuc-J-Scik Chcmism
ADKeimers
31 COMPOUNDS IN THE LITHIUM-TELLURIUM SYSTEM
D Y Va^ntine A D Keimers
It has beei k-mcns rated that tellurium vapor can induce shallow grain-boundary attack in Hasiefloy N similar to that observed on the surfaces of the fuel-salt circuit of the MSRE However the actual oxidation state or states in which teilunum is present in MSBR fuel salt an LiF-BeF-ThF4-UFlaquo mixture and the chemical reactions with the Hastelloy N surfaces remain to be determined The lithium-tellurium system is being investigated to determine which Li-Te species can be present and to synthesize samples of all possible lithium tetlurides- The solubility of these compounds in the fuel salt will then be determined In addition they will be used in spectrophotometry- and electrochemical investishygations of tellurium species in melts
During this report period sample of LijTe and LiTe
were prepared The preparations were made in an argon-atmosphere vacuum box equipped with an enshyclosed evacuated heater which held a molybdenum crucible All handling of Li-Te compounds was done in inert-atmosphere boxes sometimes the compounds were sealed under vacuum to minimize oxygen nitroshygen or H 0 contamination Lithium having an oxygen content of ltI00 ppm was supplied by the Materials Compatibility Laboratory Metals 2nd Ceramics Divishysion Tellurium metal of 99999 wt Tr purity was obtained from Alpha Ventron Products
The Li2Te was first prepared by dropping small pieces of lithium into molten ellunum contained in a molybshydenum crucible at 550degC The reaction was extremely exothermic emitting fumes and light tlashes after each lithium addition Solid formation occurred at lower lithium concentrations than expected from the reported phase diagram2 Further lithium additions continued 10 be absorbed after first melting on the surface of the solid phase An amount of lithium necessary to satisfy Ihe Li2Tc si gtichiomeiry was taken up in this manner However because of the loss of vapor and of some solid material which splashed out of the crucible during the early additions of liihium it is doubtful that the stoichi-omclry was in fact preserved
The x-ray diffraction pattern showed a single phase identified as LijTc having a face-centered cubic strucshy
ture with a lattice parameter of 65119 t OJ0O0Z A J
The oxygen contamination in the product totaled about 375 ppm- Spectrographs analysis reported 0-5 wt ~ molybdenum present Since the oxygen level and moshylybdenum impurities were fairly low a larger-scale prepshyaration wts attempted as well as a direct preparation of LiTcj by the same method In both cases rv product was contaminated unacceptabiy with molybdenum and these preparations were discarded Apparently the first preparation had affected the surface of the crucible such that the reaction with molybdenum was accelershyated in these subsequent experiments
The molybdenum crucible was used for one further preparation after cleaning and polishing the inside surshyface The Li Te was prepared from the lithium-rich side of the phase diagram by dropping tellurium info molten lithium Since molybdenum is relatively inert toward lithium4 less reaction with the crucible was expected In addition this preparation could be made at a much lower temperature The tellurium was added to the lithium in small increments with the temperature held at 250degC Each of the first additions resulted in a smooth quiet reaction with a solid phase forming on the bottom of the crucible However since completion of the reaction was not visibly apparent the temperashyture of the system was increased above the tellurium melting point to about 550degC to ensure that unreacted tellurium was not on the bottom of the crucible More additions of tellurium were then made Above 500degC a popping noise was heard after each addition of tellushyrium After about three-fourths of the tellurium had besn added the system was mostly solid As more tellushyrium was added the amount of solid in the system became so great that further additions of tellurium were
I A D Keimers and D Y Valentin MSR Program Semi atmu Profr Rep f-eh ltlt 1975 ORNL-5047p 40
3 P T Cunningham S A Johnson and F i Cairns Vlectrmhem Soc Klrcirochrm Set Tech 120328(1973)
3 X-ray lattice parameters were measured by O B Cavin of the Metals and Ceramics Division The value 65119 00002 A measured tor IiTe is in agreement with the value 6SI7 A reported by K Ziml A Harden and B Dauth Hlektrochem 40 588 11934) The value 61620 bull 00002 A measured for LiTe is in agreement with the value 6162 A reported in ref 2
4 H W leavenworlh and R F CUaryAcu Mel 9519 11961)
29
30
not covered by the liquid Subsequent additions proshyduced light flashes and poppng associated with the highly exotherrmc reaction as encountered m the preshyvious preparations oi Li Te FuuBy enough additional tellurium was added to the sgt-stem to satisfy the Li Te stoictuonietry and the system was aflowed to cool to room temperature
Upon crushing the cooled product fow differently colored substances were distinguishable gray opaque material wine-red to pink opaque material colorless translucent crystals and metafile tellurium Analyses were performer separately on each type of material
1 Gray opaque material The x-ray diffraction pattern revealed LigtTe and LiTe no other lines were present The oxygen level was about 218 pom Specshytrograph analysts indicated the presence of about 01 w t molybdenum
2 Red-hue material Only a few crystals of all-red material could be isolated The remainder of the red-hue material was ground together with some surshyrounding gray material The x-ray diffraction pattern corresponded mainly to Li2Te A small amount of LiTe was also preset The oxygen content was reported to be about 275 ppm Spectrograph analysis reported lt00I wt 9 molybdenum
3 Colorless translucent nd isolated red crystals Both these products gave an -ay diffraction pattern corresponding to pure Lij Te with no indication of a second phase
To ensure a uniform product all the various colored materials were recombined and thoroughly mixed The LijTe mixture was then placed in a 2-in-diam tungsten boat which had previously been enclosed in a quartz bottle The quartz bottle was then evacuated sealed and heated to 550degC for about 16 hr The product obtained after cooling was almost completely cream-white However when the bottle was broken open the product began to turn beige upon exposure to the envishyronment of the inert-atmosphere box The product was then crushed roughly and placed in sample bottles On standing in the bottles the product gradually reverted to the red-gray color it had been before the heat treatshyment with the exception that the product in one bottle remained beige The reason for the lack of uniform behavior is as yet unknown Some of the darkened product was returned to the tungsten boat in another quartz bottle and (he heat treatment repealed it again turned the cream-white color The products both the light beige and the red-gray color forms gave x-ray difshyfraction patterns for a single phase LijTe Analysis of this LijTe is given in Table 31
T l r 3 J ABMywafU-TcaaJliTc
UU t i l r
l l lVI 1 laquo 5 - MI 1 - bullbull It IWI ~ raquo raquo - bullbull 5 Sraquo 4 r II 5
Li TV IMgt4T I mj r i LiTe bullbulln4r ~ bull 14- 05 XI lt - 5 raquo Innh4r ~ l ITI - 1511
-fjgt diftraciMi SMctcpfc SWfJr rhue 0ypm ipeani 740lltr l 275tMrri
MatyMtmdash i w i 005 ltlaquoraquo0I
T w p m iwt i lt00l lt 0 laquo l
Red-gray Li2Te was mixed with the amount o( tellushyrium required to satisfy the LiTe stoiduometry The mixture was then sealed in a qurtz bottle under vacuum and heated to 550degC for 2 hr The not liquid was dark metallic gray On cooling the solid appeared bright silver-gray The x-ray diffraction pattern conshyfirmed the presence of a single phase LiTe having a near body-centered cubic structure with a pscdo-ell lattice parameter of 61620 plusmn 0D002 A J The well-exposed Debye-Scherrer diffraction patterns suggest that the structure of this compound is more complex than previously reported2 Work will continue in an effort to describe this structure The oxygen content was reported to be 275 ppm Spectrographs analysis reported no molybdenum or tungsten contamination Analysis of this LiTe3 is also given in Table 31
3 2 SPECTROSCOPY OF TELLURIUM SPECIES IN MOLTEN SALTS
B F Hitch L M Toth
A spectroscopic investigation of tellurium behavior in molten salts has been initiated to identify the species present in solution and to obtain thermodynamic data which will permit the determination of the species redox behavior in MSBR fuel salt A previous investigashytion 1 had indicated that Te~ is present in LiF-BeFj (66-34 mole ) on the basis of an absorption band occurring at 478 nm when LiTe was the -Jded solute however the work wai terminated before these observashytions had been fully substantiated The current work is an extension of those earlier measurements which
5 C K Bamberger i P Young and R G ROM Inorg Suel Chtm 36115raquo U974)
31
should lead ultimately to a measurement ol redox equishylibria such as
LiTe bull H bull 5LJF = 3Li2Te bull 5HF II)
^Te bull LiF + ^ H = LiTe + HF 1
These data should then permit the prediction of teilu-num redox chemistry as a function oi LF gt l T F 4 ratio
During the past several months most ot the effort was devoted to assembly oi the apparatus necessary for the fluoride measurements Ths involved fabrication and assembly- ot the following furnace for the fluoride studies diamond-windov ed specirophotometrk cells a vacuum and inert gas system and a KHF saturator through which H is passed to generate HF-H mixtures of known proportions
Also during the period of preparation some attention was given to a supporting study in chloride melts The advantages of working in chlorides are
i previous ground-work investigations have already been reported7
2 chlorides are easier to hold in silica cells without container corrosion
3 the greater solubility oi the tellundes in chlorides may reveal greater detail because oi more intense spectra
Atsorption spectra have been measured for LiTo LiTej and tellurium solutes as well as during titrations of LijTe with Tej in the LiCTKCl eutectic 31 450 to 700degC These data indicate that at least two light-absorbing species are present in molten chlorides conshytaining lithium tellurides with compositions in the range LiTe to LiTe4 Furthermore an examination of Te 2 in the LCl-KCI eutectic has indicated thai there is a second species present besides Te which is formed at high temperatures andor high halide ion activity More detailed experiments are anticipated using purer lithium lelluride solutes in the diamond-windowed cell to demonstrate (hat (he additional species are not related to impurities from the reagent or silica corrosion
6 This work has done in cooperation with J Bryncsfad of I he Metals and Ceramics Division
7 I) M Cruen R I McBclh M S I osier and ( Y (roulhiimcl Phys Otcm 70i2t472 (l6gt
3 J URANIUM TOTRAFLUOftDE-HYMOGEN EQUIUHUUM IN MOLTEN FLUORIDE SOLUTIONS
L O Gilpatnck L M Toth
The equilibrium
LF 4ldraquo4H2lg) = UF J ldraquoHF|g) HI
is under investigation using improved methods of analyshyses and control The effects of temperature and solvent composition changes on the equilibrium quotient
Q = rraquo
are the immediate objectives of this work and are sought to resolve previous discrepancies noted in fuel-sal redox behavior
The procedure involves sparging a small (approxishymately 1 gl sample of salt solution (UF 4 concentration of 0038 to 013 mole liter or 0065 to 022 mole rgt) with H gas at 5S0 to 850degC until partial reduction of UF 4 to UF 3 is observed HF is added to oxidize the desired amount of LF j back to UF 4 When an equilibshyrium between the HF H gas mixture and the UF 3 -UF 4
in solution is reached a spectrophotometric determinashytion of the UFj and UF 4 concentrations is made These data are combined with the analytically determined HF(H2) ratio to obtain the equilibrium quotient at a given set of conditions
The assembly of the system for this experiment has been completed and measurements of equilibrium quotients using LiK-BeF (66-34 mole ^) as the solshyvent have been initiated Some delay has occurred because of trace water in the HFHj sparge gas which was responsible for the hydrolysis of uranium tetra-fluoride and the subsequent precipitation of 1 0 The problem has been partially alleviated by treatment of the KHF saturator gas supply lines and spectrophotoshymetry furnace with fluorine at room temperature Howshyever back diffusion of water vapor into the furnace from the exit gas line has also caused substantial solute losses and has been reduced by using higher HF-H2 flow
This research in support of the MSBR Program was funded by the KRDA Division of Physical Research
H I O Gilpaimk and L M Toth The Uranium Tetrafluoridc Hydrogen Fquilihnum in Mollcn Fluoride Solushytions MSR Pnygram Srmunnu Progr Rep Feh u 7 s ORNI-5rt47p43
32
rates Together these modifications have reduced the totute Kisses to an acceptable level (2^ per day i
Equilibrium has been achieved at 650X lor measured I F VFj ratios of approximately 02 X IG to X 10- Although the I F VF 4 values are reproducible a fixed KHF saturator temperatures the aaalyiicaily detennined HF values are not as yet Consequently the standard error (approximately 50lt) in the equilibrium quotients is soil rather high So tar a value ofQplusmn 10 has been determined at 650degC which compares favorshyably with the previous value of 116 X I 0 T Most of the immediate effort is being Jevoted to improving the precision of the HF determination
Tritium control in an MSBR would be favored by higher equilibrium quotients In an MSBR the I F UF 4 ratio will probably be fixed by equilibria involving the structural metals The tritium inventory will be established by the tritium production rate and the various tritium removal processes UQ is larger than previously anticipated the partial pressure of HF would be higher and the partial pressure of H would be lower than previously estimated Thus TH would be available at a lower concentration for permeation through the heal exchanger to contaminate the coolant loop (and ultimately the steam system) and a larger proportion of the tritium would be present as TF which would be removed in the helium gas stream
34 POROUS ELECTRODE STUDIES IN MOLTEN SALTS
H R Bronstein F A Posey
Work continued on development of porous and packed-bed electrode systems as continuous on-line monitors of the concentrations of electroactive subshystances especially dissolved bismuth in MSBR fuel salt In previous w o r k 1 0 a prototype parked-bed elecshytrode of glassy carbon spheres (MOO microns in dishyameter) was tested in the LiCI-lCCI eutectic system Linear-sweep voltammetric measurements carried out in the presence of small amounts of iron and cadmium salts showed that the cell instrumentation and auxilshyiary systems functioned successfully and demonstrated
9 G Long and F F Blankenship The Ftahiliiy of Uranium Triflimhde ORNL-TM-2065 Part II (November 1969) p 16 Kq 6 with xjyt - 0002
H H R Bronstein and F A Posey MSR Program Semi-anmi Progr fP raquolaquo Jl 1974 ORNL-5011 pp 49 51
II H R Bronsleir and F A Posey HSR Pro-am Semi-anmi Progr Rep reh 2H IV7S ORNL-5047 p 44
the sensitivity of this method of analysts However these measurements showed the need tot redesign oi the experimental assembly to permit removal and replaceshyment of the cell and addition of substances to the melt
During this report period the redesigned packed-bed electrode of glassy carbon spheres was tested again in LiCI-KCI (5SJMIJ mote ) eutectic since the beshyhavior of a number of electroactive substances has alshyready been established in this medium The packed bed of glassy carbon spheres was supported on a porous quartz frit and contained in a quartz sheath Another porous quartz frit pressed on the bed from above A glassy carbon rod penetrated the upper quartz frit to provide compaction cf the bed ana electrical contact with a long standee steel rod which was insulated from the surrounding tantalum support tube The oiectrode assembly was dipped into the melt so that the molten salt flowed up through the interior oi the bed and out an overflow dot By this means il was possible to obtain a reproducible volume of melt inside the packed-bed electrode
Voitairmetric and coUometric scans of the pure melt at 3raquo5degC showed that the background current was small A typical set of current-potential and charge-pountiai background curves is shown in Fig 31 - A 2-V
1 1 I flmdashImdashTmdashImdashraquomdashbull 1mdash T I mdash T 1 1 T mdashi 1 I I bull 1 l - laquo 0 0
to 0 5 0 0 -OS 10 IS ELECTKOOC P0TpoundlraquoTiraquoi ( n bull laquolaquoamp) (raquobull$)
Ffc 31 Linear-sweep voUMimetry and coalonef ry of cadshymium in LCI-KCI (588-412 mole gt eutcctic with a packed-bed electrode of glassy caboa spheres Curve A current backshyground (sweep rate = 10 mVsec) curve B current with Cd present (sweep rate = 5 mVsec) curve C background charging curve (sweep rale - if) mVsec) curve D charging curve with (d present (sweep rate = 5 mVsec)
33
range ot electrode potential could be swept without evidence of significant amounts ot ouduable or reducshyible impurities in the meli For calibration purposes a known quantity ot -radmium ions lCdgt was added to the melt lraquoy anodiation ol molten cadmium metal conshytained in a specially designed graphite cup which could he lowered into the melt The amount ot cadmium adod (Fig 311 was monitored by use oran electronic autorancui couometer
Following addition ol cadmium the voifammeinc and coulometric scans indicated that only a small fraction ol the known cadi-uum content inside the void space oi the packed-bed electrode was being measured- After removal of the cell assembly examination showed flat the glassy carbon contact rod had somehow fractured possibly due to excessive pressure from the matin stainless steel contact rod and resumed in lo of elecshytrical contact with the packe-i-Sed electrod
The -ell assembly was then redesigned and rebuilt to permit electrical contact to be maintained without undue pressure and to allow accurate measurement of the working volume of the packed-bed electrode The new design was similar to that of the previous cell except that the upper fritted quartz disk was permashynently sealed (o the surrounding quart sheath A small hole in (he center of the disk permitted loading of the daisy carbon spheres into the electrode assembly and provided accurate positioning of the glassy carbon con-act rod into ihe bed Prior to loading of the spheres
the volume contained between the porous quart disks was measured with mercury
Some voltammetric and coulometric scans in the presshyence oi cadmium ions are shown in Fig- 3 1 As in preshyvious studies in aqueous media with the packed-bed electrode2 more accurate analytical results were obtained on Ihe anodic half cycle (stripping) than on bulli cathodic half cycle (deposition) Approximately 40 mC of cadmium was estimated to be within the packed-bed electrode The coulometric results shown in Fig 31 n quite consistent with this value Thus it is possible knowing the geometry raquof a packed-bed electrode to estimate the response and sensitivity within reasonable limits (the accuracy oi estimation depends upon void fraction the accuracy of the volume measurement and other factors) Repeated scans over a period of many days showed good reproducibility and also established that diffusion through the quart frits during the time of measurement (only a few minuus) has very little effect on the results
12 I I R Bronstcin and I- A Posey Otrm Mr Amu Proxr Rep May raquo IW ORiSI 4976 pp 1119 I I
Another cell was pocked with jOOp-dum glassy carbon spheres and used to obtain the results shown m Fig 32- In this case a quantity of amp ions had been anodued into the melt in a manner ssraiar to that used for cadmium- At the time of these measurements the same melt had been in use for many weeks Fig 32 shows voiiammetnc and couloroetric anodic stripping curves in the vicinity ot the anodic peak for stripping oi bismuth which had previously been deposited on the imemal surfaces of the electrode during the cathodic ^ii cycle In agreement with observations of others we found that volatility of BiCl precluded close correshyspondence between added and observed quantities of bismuth and that the bismuth peak decreased steadily with time The appearance of the bismuth peak suggests that possibly some alloying of bismuth with the cadshymium look place
Other expeiiments on bismuth reduction and stripshyping will be carried out in the future in which cadmium used for calibration of the ceil sysreni is absent In addition the present apparatus wiL be used lto study the electrochemistry oi lithium teiluride in the UC1-KC1 euieciic Observations on lb tellurium system in the chloride melt may be useful in interpretation of tellushyrium behavior in later studies with MSBR fuel salt The
CWV-3WG 75 -Z99
TEMPERATURE 392-C if REFERENCE ELECTRODE laquoflaquolaquoCMraquo4r) pound
GLASSY CARSON SPHERE OMMETER -200raquogtCfm
04 03 02 01 00 -Ol -02 - 0 3 - 0 -05 -06 ELECTROOC POTENTIAL (rtAflAflCO (bullraquo()
F J2 Linear-sweep anodic stripping votUmmetry and coglometry of hianiirh efecfrodepooted onto a packed-bed electrode of gUscy carbon spheres Solid lines experimental current-potential and charge-potential curvet in ihe region of (he rmmuh stripping peak dashed lines estimated background charging curves
34
cajxabilify of the packed-bed electrode ot ciasv carbon tfetctci tot monitoring eieciroactrve species n molten sail has hem shown ugt be sattgttactor Consequently p bull aw now under wa raquo design jpd fabrKation ot cells and appaiaius lor sestmc the electrode system in mxten fluoride media induduw MSBR fuel salt- In Msmufh-coatauung fluoride metis whether bismuth iraquo present as Bt or LijBtor both it should be possible 10 identifgt and determine ihe quantities of each species The packed-bed electrode offer hope ut removin as well as monitoring dissolved bismuth m the fuel sail which may be present as a result of the reductive extracshytion process for removal ot fission products
iS FUEL SALT-COOLANT SALT INTERACTION STUDIES
A D Keimers D t Ilealherly
In the alternate coolant evaluation1 several areas of potential concern were defined with regard to the applishycability o( the conceptual design coolant salt | a B F 4 -NaF (gt2-K mole ^ l | for MSBRs These centered primarshyily arogtmd events associated with off-design transient conditions particularly primary heal exchanger leaks which would allow imermixing of fuel salt and coolant salt If coolant salt leaked into the fuel salt the quanshytity and rate of evolution of BF j gas from reaction lt 11
N B F 4 l d raquo o l j U M - B F l g gt bull N a F i d gt u e ^ lt I
would determine the transient pressure surges to be enshycountered in the heat exchancer and reactor Also preshyvious work 1 4 indicated a substantial redistribution of the ions LT Na Be F and BFlaquo~ between the resultshying immiscible two-phase system formed on mixing Lj BeFlaquo and NaBF 4 The solubilities of UF 4 andThF 4
have not been measured in such systems thus the disshytribution of uranium and thorium between such phases and the resulting concentrations are unknown In addishytion if oxide species were present in the coolant salt either deliberately added to aid in tritium trapping or inadvertently present due to steam leaks in the steam-raising system the precipitation of UO2 following mixshying of an oxide-containing coolant sail with fuel salt has not been investigated Therefore a series of experiments were carried out to investigate these areas
I J A D Kelmirs tl al Committer Report hvaluaiion of Alternate Secondary land Tertiary) Coolants for the Molten-Salt Breeder Reactor (in preparation)
14 V K Bamberger C h Baelaquo Jr J P Young and C S Shew MSR Program Semiannu Prop Rep reh 20 I96H ORNL-4254 pp 171 73
The experimental apparatus consisted ot a a u i u vessel heated by a quuri furnace so thai the raquoraquoraquottTvr of the resukmc phases ouid be observed at temp mure and measured with a cathetomrter The quari vessel extended up out of ihe furnace and was closed with an O-itne titling and end plate A nickci stilting shaft driven bgt a constant -speed dc r-fcgtllaquogtlaquo peneiiated the end plate and during live tests was dnven at a speed adequate 10 stir the two phases without appreciable vtsibW dispersion Access for sample fillet slicks was provided through the end plate as was done also for ihe argon inlet and exit lines A very low argon flow main-tamed an inert atmosphere over ihe melt during ihe experiment
Predetermined weights of fuel salt (nominal composishytion LiF-BeF ThF-lF 4 (Mfc-117-03 mole^raquo | and coolant salt |nominal composition NaBF4-NaF (2- mole ltl| were placed in the quart vessel and rapidly healed lo 550 C Bubbles of gas could be observed due to BF) generation via reaction I I I as soon as the coiilani sail melted during the heat up period When the temperature reached 550 ( counted as time zero stirshyring was initiated The volume ol the phases was periodshyically determined and filter-stick samples were taken at 30- or dO-rrun inieials
The reaction between the fuel salt and coolant sail proceeded slowly approximately 30 to raquo0 min was required to complete the visible evolution of BF 3 gas at 550degC When the initial coolant salt content was 20 wt or less of the total material no omlant salt phase remained after approximately I hr All the NaF disshysolved in the fuel salt phase and all the BF gas left the reaction vessel With larger initial weights of coolant salt up to 50 wt gt a small residual volume of coolant salt phase could be observed after I to 3 hr Severe corrosion of the quartz reaction vessel occurred at the interface between the coolant salt phase and the argon cover gas in the experiments with the larger initial weights of coolant salt presumably due to attack of the quartz by BFj via a reaction such as
2BF(g) + VjSiOjfc)- SiF4fggt + fcOjfd) (2)
In experimenis 6 and 7 holes were corroded completely through the vessel wall and the surface of the stirred molten coolant salt phase was exposed to air for I to 2 hr at 550degC
In most of the experiments samples of the fuel-salt phase were withdrawn at intervals of 1 2 3 and 4 hr Samples were also taken after the conclusion of the experiment after the melt had cooled to room temperashyture the quartz vessel was broken away from the solid salt All these samples gave essentially identical analyti-
Tabic 32 Compmiliun of fuel-Mil pliiH- ami cnulani-aalt phatv aflci contact al 550 C
h vpcrimenl No
Initiil imvlmc iwt raquo
Hu-I salt Coolant i lr
100 9( Ho 7l) 61) 51)
o II) o 3raquo 41) 51)
111
tgtHK 6 3 3 604 544 50H 44 0
I uclvill phase (mole gt
Nal IK-1 M i l I T
2 3 93
123 1911 63 366
17J 167 165 155 13 H9
NominaUomnoMUon l i l - -Bc l - -Th | - lt - l l (72-I6-I I7-03 mraquolc bull)
Nominal conipotttion Naltl- -Nul (92-K mole bull I
No coolant-suit phase remained
Not analyzed
115 105 106 |lgt9 96
ID4
I I I
I bull i2 IVH 94
Nal-
191 366 43 9
CoiiliiHvih phase IIIIOK- I
IWI l h l bdquo I T N i S i l
4 4 3H 3 9
ii IH n o l i (150 0 017 1)74 OlOH
lt 31 19
M 0 Nalll
lt5l IK 6 J 33
n 47
16 9
ft
36
cat values therefore tne fuel-salt phase analyse (Table 52) represent an average of 5 to 5 values Further supshyport lor the coateatun that react urns nrroHuK the fuel-salt phase were complete m feO mm c less t shewn In the plots of volume rs time in Fig3J The cootani-sai phase volume decreased raptdry tor about 30 mm due to reaction (1) thereafter the volume chance was slower presumably due to reaction i2h
It was irnpossibie to obtain coobnt-salt phase samples with the flier sticks both because the phase volume was small and the salt tended to dram out of the titer sticks Therefore aM coolant-salt phise analyses (Table 33) were from samples obtained after completion of the experiment and represent only smgje values
The analyses (Tabic 3 Jraquo show substantial redistribushytion of the ions Li Na and Be between the two phases Thorium and uranium exhibited low soiubiity in the coolant-sail phase Neither NaBF4 nor the oxyshygenated tluoroborate compound (represented as B 0 3
in the table) was soluble in the fuel-salt phase Fuel salt stirred in contact with a coolant-salt phase containing up to about 50 mole lt B0 3 showed no precipitation of LO Tht coolant phase compositions were ex-
onNL-DWG 75-raquo3748
rlX Claquo
1 0 -
X T
Cootant Solf Phase -
20 40 60 80 TIME (mi)
100 120
Fit bullbull Votame of coobnt-s-Jt phase and fad-nil phase vs fane in mixing experiment No 6 Initial mixture was 60 wi i fuel salt and 40 wt 1 coolant tall After heatiny lo 550deg C Mining was begun and tht depth of the two phase was periodishycally measured
F-laquo O
I n t u t i laquoaraquo4c bull
factual (bull4jac vilr Ml lt) ViM
l raquo bullbullbull 4gt gt- 5 bullbull bullraquo 4i M bullraquo bull bull bull
bullraquo 5 gtraquo MI 14
raquo - Na Nan bull Li bull ZBc bull 4Th bull 41 bull 4S
pressed (Table 33) m terms of the ternary system MF-B 0-NaBF 4 The compositions are dose to the glass-forming regions of the terra y phase diagram1 for the system NaF-BiC-NaBF where drscete comshypounds have not been established
The following pertinent observations can be made
1 The rate of evolution of BF gas on mixing was low- presumably the rate-limiting step is the transfer of NaF across the vflt-salt interface Thus in a reactor system with turbulent flow the release would be more rapid however these results are encouraging relative to MSBRs in that very rapid gas release reshysulting in significant pressure surges was not experishyenced
2 No tendency was observed for the fuel salt constitshyuents thorium or uranium to redistribute or to form more concentrated solutions or to precipitate folshylowing mixing of coolant salt into fuel salt These experiments do not yield information relative to mixing fuel salt into coolant salt since it was impossible to contain predominantly coolant-salt phase mixtures in quartz at 550C Thus the quesshytion of uranium (andor thorium) precipitation as lF4-NaF complexes as observed in an engineershying loop remains unresolved
3 Apparently an oxide species forms in the coolant-salt phase which is more stable than UOj since no LO-precipitation was observed Thus large amounts of oxygenated compounds could be added to the flu oroborate coolant salt for the purpose of sequesshytering tritium since leakage of such a coolant salt into the fuel salt would not lead to uranium or thorium precipitation
15 I Maya Sect 41 this report 16 H F McDuffie et al Assessment of Molten Salts ar
Intermediate Coolants for IWBRs ORNL-TM-2696 (Sept 3 1969) p 20
37
3 4 LATTICE AND FORMATION ENTHALHESOF FIR$T4tOlaquo TKANSmON^ETAL FLUORIDES
The pnmar bull purpose of (his inveMijpinw is to plaquoraquoraquowde a theoretical bans tor cnttcaiK evaluating the chermir-dynamic data thai raquoifl be blamed in an experimental program recently giiittled with Dmstuti ot Physical Research I undine In thf experureirraquo free enerpes of tormaiion will be deduced from emt measurements ot solid-etectriJyie caharuc ceHs The iirsi-roraquo transition rrcials include common sKucturai metab (Fe i Cgtraquo and other meuls iTi V) which may be used in fcaon or fusion reactors When these meuls are corroded or otherwise oxidized u fluoride media used m these resc-tors meial fluorides are formed reliable thermoshydynamic information for these compounds rs valuable in predicting their chemical behavior in the eactor system
For a metallic fluoride MFbdquo I where n is the valence of the metallic iongt the relationship between lattice enthalpy V and enthalpy ot formation is given by the equation
_y=-X Mgtbdquo nXly- ( I t
The lattice enthalpy is the best of the reaction
Mlggt + nV it) = MFbdquo(c) Craquo
at gtvl5 K The lattice enthalpy is very similar to the lattice energy the latter being someihat more diffishycult to obtain from experimental information 3Jr is the standard heat of formation of MFbdquo(c) A- is the standard enthalpy ltraquof formation at gtHl5 K of the gaseous cation and electrons ((gt formed from the crystalline metal
Hc)Mltg)+ gtlt( g) lt3gt
A-bull- is the standard enthalpy at ZW^K of a mole of gaseous fluoride ions formed from the ideal gases electrons and diatomic fluorine
V2F(sgt + ltr(g) - F (gf lt4gt
The enthalpies of formation for reactions lt3gt and (4gt are deduced mostly from atomic or molecular data Abdquo is obtained by summing the first ionization potentials of M and its enthalpy of sublimation and covcrling these quantities where necessary to 2ltraquolaquoI5 K values of bdquobull are given in Tables 34 and 35 The enthalpy of reaction (41 at gtXI5degKis ol24
Hmrraquotc bull Leal rrv-fcr
lt j l yi 5 4ilaquo 6 2 = si laquo2vraquo bull ltlaquo5i-Tiraquo bull 2 i v 5Slaquogt bullMgtC gt i2Wr 2raquoraquo i raquo f Crl I1 - 5 o5 3 6 - 5 Mnl 2ltgt5 4 - lf raquo 5 1 - I l-lt tif - 5 fc5s raquo - 5 C l - t5 - I f 2 laquo I V I 52 - bull raquo3 5 5 - bullltbull
t u t I I -bullbull 323 41 - - N nraquo I N Mraquo5 25
llaquolaquojgtltn rgt cntui-gt rmdashm lt I raquo-raquo- SRIgtS-IraquoS 34 bullgt cnhjlprs i ^uNinurn-n irin ret igt (atenve raquorjc prpjutraquogto encris sorretttrto irraquom elt 2 N BS Iivhnuai N-te 2gtMgt i llaquoI i ^iinucJ in this intetripibii ^NBS Icchnicjl V-ie bull-raquo 11t11 r V Rrufchiu tr j | iTim ThrmoJvn 6 bullbull( tgtraquo4( iXrrmrd tflaquom vgtlij ltal inkveil emf JJJ snmi in W H Sfcltr|[4i jnd J W Pjiicrv-n -laquoWtmmtm Mfidt 31 4 11 raquo-laquoraquo
f-IV-iF Thermhemif tehlt 2J e j NSRDS NBS 11111 I- Rudiicl jl J Oum rnt AifJ 1213 laquo11^1 NRS TcYhnhil tir raquobull lt fftSraquo
kcal per gram-ion it is based on Popps value 1 7 (34(H) eV) for the clectr gtn affinity of fluorine the dissociation energy lt 15 eV) measured by Chupka and Berkowit and the enthalpy difference of F (ideal gas) raquoraquo Hbdquo listed by lluiigren et al 1
The lattice enthalpies of the divalent fluorides arc listed in Table 34 and are plotted against atomic numshyber in Fig 34 The curious double hump has been intershypreted 2 0 in terms of ngand-field theory By this theory differences between actual values of A and those lying on a smooth curve drawn to fit the data of C a F Mnlj and ZnF are primarily due to ligand-field stabishylization energy (LFSfcl For (his series of compounds
bullThis rclaquoearcli in support of the MSRR Program wilt funded hy iho l-RIA Division of Physiiiil Research
17 II P Popp Xatitrforuh 22a 254 117) 18 W A ( hupka and J Berkowil Oiem Pint 54542h
ii nn 19 R Hullcren el al Selected ialun of the T)icrmltgt
dynamic Properties of the Elements p 177 American Society of Meials Metals Park Ohio 1973
2lraquo P (leor-e and tgt S McCliire p 381 in Progress in Inorganic Chrmisln vol I I- A Cotton ed Inieruience New York I W
M
750
_ TOO mdash
o E
x
690
6 2 0 -
I I I I I I I
I I I i I I I I I Cefj Stfj Traquoj V Crfj M Wgt laquo j MF 2 C 2 amp2 ddeg (T d 1 d J d 4 5 draquo d draquo draquo d
Fltg- 34 Lattice wlnaifiM of 3rf diva l l w i l u Solid circle (bull) are experimental aML catenated from Eq 11)error bars art uncertainties in ampH Open circle (-) are AftL mam Iwand-fldd stabilization energy Tnangks (A) arc aW^ minus both LFSE and Jahn-Tener energy Solid squares ltbull) were estishymated by adding LFSE plus 3 kcalmote as an empirical correcshytion to the smooth cone
the ligands are fluoride ions octahedrally coordinated (except for CaF 2 ) to the cation the ocuhedral field of fluoride ions acts to stabilize the splitting of tf-electron energy levels of the metal ions In a spherishycally symmetrical field the (-electron levels would be degenerate that is be at the same energy In Fig 34 the smooth curve drawn through for example N iF 2
represents the ampHt N i F 2 would have if the field of fluoride ions around the nickel cation were spherically symmetrical Octahedrally coordinated cations with unfilled half-filled or fully filled 2d orbitals will not have a ligand-field stabilization energy hence a smooth curve is drawn through CaF(tdeg) MnF(lt 5) and ZnF2(ltdeg)
Values of the LFSE can be deduced from optical spectra For FeF N i F 2 and CoFj subtraction of optically derived LFSE (Table 36) from bHL yields values (open circles in Fig 34) which are above the smooth curve by 2 to 3 kcalmole Similar LFSE subshytractions for CrF and CuF yield values (denoted by
laquoraquoraquo-raquo
Fhoodc iHf bullraquo- plusmnHL
ikai nMle) ileal mmfT l U a l motel
ScF 3941 2 1112 13224 r 2
w 33 1 3-$ 1222 1374 t 35 V F 2 9 S S I29raquo 1499 O F 277 US 14 I44S l 2 3 ^ I3gt l 143 t F e f bullSHi 13V4 1431 3 CoF mjf 1455-J 1457
N O W 1515-5 bull I 4 9 7 C - F ( 1 2 0 I S M 11520 lt - F 2 7 I3S9 143
bullban pomoMs from C E Moore SSKDS-NBS 34 (1970) earailgiri ot inlilmdashiliun from ref 19 catrnce state preparation energy correctnas from rcf 20-T N KeiaHani cf a l Cktm Tkrrmodrn t90 (1974s eO Kabascfccwsfci et at pp 3343S4 in JMrMftWpaf Iktmso-chematry 4th cd Pergamon Oxford England 197 Derived from toad garantc-cdl emf data gjien in W H Skdion and J W Patterson Less-Common Mruls 31 47 (1973) MBS Tetkmfl Note 270-4 (1969) fjASAF TkermochemicM Ttblts 2d ed NSRDS-NBS 37 (1971) Estanaied m this mvcstiplion hNBS TethmeitSote 270-3 (I96S)
open circles) above the smooth curve by 5 and 7 kcalmole respectively Both C I F J and CuF 2 (and to a lesser extent F e F 2 ) are known from crystal structure data to exhibit major tetragonal depai mdashres from octashyhedral coordination geometry This is attributed to the Jahn-Teller effect 2 which confers an additional stabilishyzation energy (Jahn-Teller energy is abbreviated herein as JTE) For CuF 2 and F e F 2 the JTE can be derived optically (Table 36) When LFSE and JTE are addi-tively applied to CuF 2 and C r F 2 the lattice enthalpy is overcorrected as is shown by the triangles in Fig 34
The methods outlined above can be applied to predict A t for V F 2 and T i F 2 Neither compound would be expected to have a significant JTE The formula used is
(5) Atfpound (kcalmole) = AHL bull LFSE + 3
where A V is the value for the compound lying on the smooth curve in Fig 34 The 3 kcalmole on the right-hand side of Eq (5) is an empirical correction reflecting
21 F A Cotton and C rmced Inortnic Chemistry 1972
Wilkinson pp 5deg0-93 in Ad 3rd rd Inter science New York
J9
OFSEk UTEXwl
IkvWt i lrgtH
H raquo T i 4 r |-ltU| OK laquo bullk-jl BRiic bull id lt
III ik^ai n-4ri
J S - l iraquoraquo I l raquo laquo n f i bulllt bull-
J- T i l bull I l Twr bull Mi t | 5 _ W 3raquo4
Jy gt f rlaquolaquoraquo laquo bull gt lt l | 4J6laquoI 5 laquo raquo l
J O K 1 laquobullbull l l raquo lt raquo I l f M a t l~4im bull bull bull I i
J- YtY 6raquogt - a I4i raquo -9
lt t raquo l 114ml lvi
J t raquo l Z l K I lb 5 Nil- lfc21 T I
J N i l 4 i m 54 lt u l I4UI0 4X4
J lt u K 4iKi 15 bull ~5t l raquo
JVjluc tivcn in D Orlkru Strut I RonJmg Berlin- 9 I 2gt 11raquo~Iraquo unlf otherwise m-JiutrJ l I SI minuinl very rlaquouchlgt i bullbull of Til- BiscJ ltgtn K N i F i l
Ksiirruted by jviumini lWgtq n ihj of Til-
Bjlaquod n iNH i gtVI Klinutrd hy Jraquorlaquonltcn mclhod |igtIX) jr r =1 -raquoltraquo cm --bullraquobullraquo Rouen t-Mirruic from JTI oi CuK Hiraquo-d n K( raquol ( ( Allen and K O Warren Struct laquorraquonWf SWw 9 Igtraquo7 nlaquogt| i
40
1550r
1500-
I I I I ORNL - DWG 75 - raquo3750 r I r
i i i I I l l I I ScF TFj VFj Crf MrF5 FeFj CoFj IWF CvF(ZnF)GaF ddeg d d d 1 (J4 d s dlaquo d 7 ltfraquo draquo d laquo
Flaquo 3 3 Lattice enthalpies of id trivalrnt Amides Solid bulltrclraquo laquoraquoi ace experimental plusmnH calculated from Eq (1gt error ban are published uncertainties in plusmnh Open circles ( ) are Af minus ligand-fteld stabilization energy Solid squares (bullgt are estimated by adding LFSF to the smooth curve
the difference between theoretical and thermochemical lattice enthalpies for NiF2 and CoF 2 The standard enthalpy of formation (Aygt for TiF2 and VF 2 is then obtained from Eq (1) and is listed in Table 34
Analogous considerations were applied to study AW for trivalent fluorides The data and results are preshysented in Table 35 and in Fig 35 The double-hump pattern of the data is evident in Fig 35 Subtraction of LFSE (given in Table 26) yields very satisfactory agreeshyment between theoretical and experimental lattice enthalpies of VF 3 and CrFj the agreement for TiF 3
(and for CoF 3 ) is less satisfactory As may be seen by the open circle below the curve in Fig 35 subtraction of LFSE from AHf overcorrects MnF 3 This is someshywhat surprising since MnF 3 with its 3d electronic configuration for Mn also has a azable JTE (Tabe 26) f the JTE were also subtracted the discrepancy from the smooth curve would be much greater In short the thermochemical data for MnF 3 are questionable
In estimating $HL and A for NiF 3 and CuF 3
(Table 35) only the LFSE was added to the spherically symmetrical values (ie smooth curve values) of ampHL In other words Eq (5) was applied without the empirishycal correction of 3 kcalmole
With regard to the A of the structural-metal fluoshyrides the theory as applied above suggests that there is little need to determine AVf for NiF 2 Moreover from the value of Afy of TiF 2 obtained in this study it is understandable why TiF 2 has never been prepared as a pure solid it can be easily shown that TiF 2 would readily disproportionate to TiF 3 and Ti However a more accurate experimental determination of A7 for TiFj would be desirable for both practical as well as theoretical reasons The same may be said for V F 2 VF 3 CrF2 CrF 3 FeF 2 and FeF 3
4 Gootint-Sak Chemistry A D Ketmers
41 CHEMISTRY OF SODIUM FLUOROBORATE
L Maya W R Cahill
The composition of the condensable fraction of the vapor piiase in equilibrium with molten fluoroborate can be defined by the system HuBF 4-HB0 2-H 20 as described in the previous report1 The work done durshying this report period was aimed at spectroscopic identishyfication of the molecular species present The B NMR as well as IR and Raman spectra of BF-2HjO FSFi(OHh- and of other intennediate compositions was obtained Dihydroxyfluoroboric acid (DHFBA) participates in exchange processes which could be desshycribed by the following equilibria
2HBF2(OH)2 = BF -H 2 0 + HBO
BFj-H 0+HBO = BF-2H 20 + HB0 2
The presence of HjBOj and HB02 was detected by 1R and Raman spectra and the pronounced broadening of the F and B NMR signals is an indication of exshychange processes The Raman spectrum of DHFBA indicates that this compound is a tetrahedral molecule Exchange processes were not detected for BF 3-2H 0 This compound appears to be stable at room tempera-twe The structural information derived from the Raman spectrum which identified BF 2H 2 0 as a
tetrahedral molecule agrees with the x-ray structural determination2 of this compound
Additional samples of condensate collected during the operation of the Coolant Salt Test Fanlity (CSTF) were analyzed (Table 41) Silicon is present because of attack on the glass trap used to collect the condensate Variations in the chemical composition of the samples can be interpreted as an indication that the condensed material is not a single molecular compound but rather a mixture formed by combination of the simpler gasshyeous species present gtn the system that is H 2 0 HF and BF The relatively high tritium content of these fractions should be noted Tritium is present in the system since some oi the Hastelloy N in the Icop was originally used in the MSRE The condensates show a tritium concentration factor of about I0 5 relative to the salt suggesting that fluoroborate coolant salt [NaBF4-NaF (92-8 mole )] may be sn effective means of concentrating and conveying tritium out of ikt system
Attempts were made to generate a condensable fracshytion in laboratory-scale experiments by heating oolant salt containing up to 200 ppm H as NaBFOH to 400degC in a closed system equipped with a coid finger The OH~ concentration in the salt decreased to 50 ppm and the composition of the condensate in a typical run was 532S H0BF 41483 (H0) 2SiF t anr 32^ free water found by difference The boron concentration in the condensed material did not reach as high a level as in
ORAL summer participant I L Maya MSR Program Semiannu Progr Rep Feb 28
VZ5 ORNL-5047p47 2 W B Barn and G B Carpenter Acta Ova 17 742
119641
TaMr 4 1 Analyses of CSTF trap coadeasttes
Sample Operation period Amount Chem
HOBF
ical compoMt ion Tritium content
imCifi Operation period Amount Chem
HOBF HBO SF
Tritium content imCifi
1 2 3 4
1972 11475 12475 31475 41575 41575 56lt75
Not avail 100 me
25 f 800 me
604 923 841 830
157 0
124 121
Not del 21 40 01
08 lo 30 r
57 34 06
Approximate amount Some of the material remained in the trap ^Difference(torn I0fr nH0 Given at a ranee Apparently more than OM simple was analysed for tritium content Data from A S Meyer and J M Dale Anal Chem [Mr An mi Pto0 Rep Jan 1974 ORNL-4930 p 28 The loop was not in operation between 12475 and 31475
41
42
the CSTF samples and there was considerable cor-bullosion Nevertheless these experiments showed a posshysible mechanism for the conversion of dissolved NaBFOH into a volatile fraction
An apparatus was assembled to measure he vapor d^rcity of BF i -2H G and related compounds at eleshyvated temperatures to determine the degree of dissociashytion of these materials This work tested the hypothesis that the condensable materials collected in the operashytion of the CSTF are completely dissociated at opershyating temperatures (+00~600C) and only combine to form more complex molecules in the colder parts of the system The procedure consists in measuring the presshysure developed in a closed system conuining a known amount of BF -2H 2 0 or DHFBA in order to establish the degree of dissociation according to the equilibrium described below
BF-2H 2 0 = BF+2HjO
At this time volumes in the apparatus have been detershymined and pressure determinations have been made using argon as a test gas Initial runs with BF 3 2H 2 0 indicate that this compound may be completely disshysociated at 400degC
Work on determining the oxide species present in molten fluoroborate is being continued and the survey1
of the system NaF NaBF4 BOj at 400 to 600degC has been extended to include IR and x-rav diffraction analyses in addition to physical and chemical observa-tiorii of the behavior of ^elected compositions The observations indicate that there are three main areas in the system
1 A region of compositions in which BFj is evolved This occurs with compositions having a deficiency in terms of equimolar ratios of NaF relative to the B 2Oj present
2 A region of compositions in which stable glasses are formed on cooling This corresponds to mixtures containing more than 33 mole B 2 Oj
3 A region in which crystalline phases and glasses coshyexist The tendency to form glasses on cooling decreases with decreasing B 2 0 j content
Usually coolant salt (NaBF4-NaF (92-8 mole )| contains relatively small amounts of oxide up to 1000 ppm and its composition lies within area 3 thus work has been directed toward characterizing the oxide species in this area At least two species were present one formed at the boundary of the glass area (high oxide content) and the other was NajBjFraquoOj which formed in compositions having NaFNaBF 4 B 2 0 mole ratios of 221 and 241 and was possibly present in
compositiors containing as little as 3 mole 7c BjOj Experiments at the 15 to 40 mole B Oj level approaching the coolant composition have been imshypeded by the relatively low sensitivity of IR and x-ray powder diffraction The difficulty with IR using the KBr pellet method arises from the fact that ~t thlaquoe oxide levels the only band not covered by BF 4~ absorptions is the one at 810 cm 1 This band has a relatively low absorptivity and it is common to NaBFOH NaiBzF0 N a B F t O and possibly other BOF compounds although the intensity and line shape are different for each compound A more certain IR identification can be made only when at least two topical bands can be identified (presently observable only at higher concentrations) as was the case in the identification of N a J B 3 F t O J at an oxide level correshysponding to 14 mole BJOJ Difficulties with x-ray diffraction arise from the low sensitivity of this techshynique coupled with the fact that the species have a tenshydency to form glasses Raman work on melts is being planned as the next step in this study
42 CORROSION OF STRUCTURAL ALLOYS BY FLUOROBORATES
S Cantor D E Heatherly B F Hitch
Alloys containing chromium in contact with molten NaBFlaquo-NaF would be expected to form a boride beshycause the reaction
(I + jr)Cr(c) + NaBF 4(d) + 2NaF(d)
= NaCrF(c)Cr xB(c) (I)
has a negative standad free-energy change (AG 0) At a temperature of 800degK ACj 0 o = - 1 0 kcal This value is based on an estimated standard free energy of formashytion (SGj) of NaCrF of -600 kcalmole In reaction (I) the exact value of x is unknown however AG of the more stable chromium borides (Cr2 B Cr5 Bj) is estishymated to be - 2 2 kcal per gram-atom of boron1 In nickel-base alloys reaction (I) may proceed more readily because of the probable exothermic nature of the reaction
CrTBfcgt +yNKalloy) = Cr(alloy) bull NiyBfc) (2)
3 O H KrikoriMl EstiirMion of HtJl Capacities and other Thermodynamic Properties of Refracsorv Borides UCRL-51043(1971)
4 O S GordkiN A S Dnbrovm O D Kokimkon and N ACherkovfun toys Chem 44431 (1972)
43
Assuming that AG of NiyB equals its enthalpy of formation AG for reaction (2) is about - 3 kcal per gram-atom of boron
An experiment to determine the extent of boride formation in the nickel-base alloys Hastelloy N (7 Cr) and Inconel 600 (15 Cr) has been in progress for sevshyeral months In this experiment mrtal specimens are equilibrated with NaBF4-NaF (92-8 mole ) at 640degC under an argon atmosphere and are periodically reshymoved washed free of salt using water and analyzed by spark-source mass spectrometry (SSMS) and less routinely by ion mkroprobe mass analysis (IMMA)-1
Analysts for boron on specimen surfaces by SSMS sugshygests some boride formation Hastelloy N specimens that had equilibrated for up to 129 days were found to contain 30 to 1000 ppm B Inconel 600 specimens conshytained 80 to 2000 ppm B Control specimens that had not been in contact with the molten salt showed 5 to 20 ppm when analyzed by SSMS Boron in Inconel 600 increased with equilibration time but with Hastelloy N the data were much more scattered and showed virshytually no time dependence
Several specimens analyzed by SSMS were also investishygated by IMMA Boron was present within the first few hundred monolayers of metal in inclusions also conshytaining sodium and fluorine in specimens of 2 Ti-modified Hastelloy N that had equilibrated for 72 days These contained 150 ppm B as determined by SSMS
5 Spark sowce mas specttomeuv and ion microprote mau analyss performed by die Analytical Chamstiy Dmson
The only plausible explanation seems to be that some NaBFlaquo remain on (or in) the metal surface despite the vashing (5 -10 nan in boiling water) intended to remove adhering traces of salt Some of the scatter in the boron analyses by SSMS is probably due to salt contamination of the metal surface Inconel 600 specishymens scanned by IMMA sholaquoed a similar pattern of surface inclusions contami^f B Na and F Unfortushynately IMMA does not provide quantitative analyses for these elements As yet the extent of boride formation cannot be quantified in either Hastelloy N or in Inconel 600 by a combination of SSMS and IMMA Probably however reactions (1) and (2) occur to a small extent boride is deposited at levels not greater than 500 ppm bullin Hastelloy N and not exceeding 1000 ppm on Incond 600 after four months of contact with molten NaBF44aF
IMMA was also used to obtain depth profiles of alloy constituents through about 5000 layers In control specimens elemental concentrations were uniform with depth far equilibrated Hastelloy N molybdenum was uniformly distributed throughout the depth explored but chrofiuuip and titanium concentrations increased linearly from the surface inward the iron concentration appeared to decrease slowly with depth Equilibrated Inconel 600 showed virtually no chromium in the fust 500 layers but chromium increased linearly in the next 4500 layers iron and nickel were uniform through the depth studied Thus IMMA indicates that chromium is selectively oxidized by NaBF -NaF (92-8 mole gt or by oxidants contained in this molten mixture
5 Development and Evaluation of Analytical Methods
A S Never
51 IN-LINE ANALYSIS OF MOLTEN MSBR FUEL
R F Apple D L Manning
B R Clark A S Mever
Corrosion test loops described previously have conshytinued operation with circulating reference fuel carrier salt LiF-BeF2ThF4 (72-16-12 mole ^ ) No additional loops hart been placed in operation during this reportshying period although several ire expected to begin opera-lion within the next few months
Measurements of the U-3 ratio in the forced conshyvection loop (FCL-2b) indicate a steady-state value of about 100 (Fig 51) This is somewhat lower2 than the
1 H E McCoy el al MSR Program Senumnu Progr Rep ug 31 1974 ORNL-50 I p 76
2 A S Meyn ec al VSt Program Semtcnnu Pro Rep Feb 28 1975 ORNL-5047 p 52
i MNL- om 75-1205
lt 1 1 1
3 V f mdash
amp amp amp
s 8 - i
bull bull
c I -J
m c
1 - i
-
2 bull bull
1
bull bull bull bull bull bull
raquo
bull bull bull
J _
bull bull
bull mdash
90 100 ELAMCO Tim
ISO 200 ltlaquobullraquoraquo)
apparent steady-state value obtained with the fluorid mixture LiF-BeF-ThF4 (68-20-12 mole 5gt indicating a less oxidizing melt The melt which started al a ratio of around 1000 reached this level via a redox process which presumably involves iactraquolaquoi ith the chromium in the walls of the vessel or in the specimens No atshytempts have yet been made to reoxidize the U3 in the melt by suitable additions of NiF or some other oxishydant It is interesting that the decrease to a steady-state value occurred after about 75 days ith a rapid deshycrease in the first 30 days Previous data from the expershyimental fuel showed2 a rather stable value near 10 for aoout 60 days until beryllium additions were made to force reduction of the U4
Some of oscillations in the data probably result from air contamination with subsequent oxidation when the loop was down This was most prominent with the experimental melt (68-20-12 mole S ) when the U43 ratio was substantially greater than the steady-state value reached at a later date
Ratios of U7U measured in the two thermal conshyvection loops NCL 21A and NCL 23 are summarized in Figs 5_2 and S3 respectively No unusual trend is apparent in the oxidation-state history of the fuel melt in NCL 21 A This loop was operated for about 240 days with Hasteiloy N corrosion specimens The curve shows a rather dramatic rise in the ratio whenever new specishymens are added This effect is attributed to additions of moisture and air which partially oxidize If3 A recover to lower ratios follows each increase in repetitive fashshyion
rj 1 t
OMl-Mt 79-OOSr 1 1 i
5 w i 1 V z
s Jr X
I bull 1
i 1 f
4 ^v bullw raquo bull
1
mdash bull
i i
bull bull
1 A- 1 100 190 ELAPSED TMfC
200 I )
290 300
FfcS1 Lmdash l gtFCL-2fc Fig 5J
NCL-m vmdashw
44
45
ORNL- DWG 75-12055 i i
1 i 1
2 bull 4 mdash 8s laquobull bullo
=3 i 3 bull copy
y i
bull bull bull bull I 1
i X bull bull bull
bull I I raquo IA raquo s s
bull bull bull bull bull bull
bull bull bull bulllt
laquo bull
I i 1 1
50 100 150 200 ELAPSED TIME (dors)
F4- 5-3- L LJ- ratios M rfcemal cowcctioa loop NCL-23
250
The U in the mdl in the Inconel 6CI loop NCL 23 wso aptdly retiuoed untS a V^iU ritio of around 40 was reached Since then the ratio has continued to decline reaching a relatively stable value near 5 The high level of chromium in the Inconcl 601 (23 wt lt) provides a sufficiently active reductant to reduce the U 4 more extensively than has been observed in Hastel-loy N loops therefore the greater U 3 concentration is not surprising
S2 TRITIUM ADDITION EXPERIMENTS IN THE COOLANT-SALT TECHNOLOGY FACUITY
R F Apple B R Clark A S Meyer
One major concern in the development of an MSBR is the release of tritium to the surroundings A potential method for limiting tritium release rates to acceptable levels involves trapping and removal of the tritium in I lie secondary coolant system This method must be tested before a complete understanding is possible of the manner by which tritium will be retained in an MSBR The present series of tritium addition experishyments involving sodium fluoroboraie will provide data on his method
The Coolant-Salt Technology Facility (CSTF) is being ltperated for testing the NaBF4-NaF eutectic mixture
with regard to its suitability as a oossible secondary coolant system In cooperation with loop engineers and technicians the Analytical Chemistry Group has been engaged in experiments to determine the fate and behavior of elemental tritium added directly to the cirshyculating salt to simulate at least in part the predicted transport o tritium into the coolant system via diffushysion through the primary heat exchanger This section describes the methodology and results of the first two experiments
About 80 mCi of tritium (diluted about 11000 with protium) was introduced into the salt stream over a period of about 11 hr beginning on July 17 Tritium concentrations were measured in the salt and the cover gas during the addition and for several days thereafter Salt samples were collected directly from the pump-bowl access port with a copper thimble covered with a copper frit One-gram samples of the cooled salt were diluted volumetrically and aliquots were mixed with a scintillation emulsion for beta counting
Cover-gas sampling has proven to be somewhat diffishycult At present a sidesfream is being sampled the diffishyculty arises from the passage of this stream through a nickel sampling line that is not completely inert chemishycally to cover-gas components Thus the amount of eleshymental tritium finally measured may not be an accurate
46
measure of tritium level within the loop gas system-More definitive experiments will require the use ot inert precious metals in the sampling system to remove doubt of chemical alteration of the cover-gas stream composishytion by the sampling system
The off-gis collection train consists of
1 a series of three water scrubber pretraps which serve to trap BFj and any other water-soluble compounds
2 a hot (400degC) copper oxide-tilted tube 3 a condensation trap to collect water formed in or
passing through the copper oxide 4 a liquid-nitrogen cold trap to remove the last trices
of water 5 a wet test meter to measure the volume of the iner
gas component of the cover gas that is helium
Results of the first injection experiment are summarized for the offgas (Table 51) and salt (TaWe 52)samples
Several days after operation had begun some liquid collected in the short glass section between the stopshycock used to divert the gas stream and the first trap in the analysis train The liquid was washed from the glass counted and found to contain about 60 jiCi of tritium This discovery clearly complicates the interpretation of previously collected samples since a large portion of total cover-gas tritium never reached the analysis train Furthermore no conclusion is possible regarding the chemical state of the tritium in the liquid The data suggest urn the concentration of elemental tritium
TabkSI TritimroMcM
iaCSTF
Tritium in ltas Time tpCimO
HOvluWe Fiemcnlai
17 1046 23 34 1305 07 12 1700 14 170 1 9 i i 1 93 2243 14 830
18 0100 32 420 0805 73 61 1000 44 71
19 1037 790 62 21 0905 1800 13
1325 50 13 22 0925 55 58 23 1303 85 29 24 1000 300 22 25 1315 340 26 28 1245 10 27
TaMrS2 TtitmmcoatcM mslaquot sMf tn rflrtfiol w i l i i jjiiwon mCSTF
Date July
Simple No
Time Tritium inCi (l
1 45 IKW 12 46 I3MS raquo 47 1512 35 4 1718 51 49 1930 9 j 50 2145 73 51 2321 H 2
1 52 1102 32 53 1912 20
laquo 54 9130 15 SMV 0952 75
21 55 1132 16 bullraquo2 56 1400 16 23 57 1330 20
increased in both the cover-gas and salt samples when the liquid was washed out between sampling periods I July 23-25)
A second tritium addition was made August 5 During this experiment no changes were made in the sampling apparatus but that region of the sampling train (desshycribed above) where liquid had been accumulating v as washed with each sample collection and counted sepashyrately The tritium found there was added to the water-soluble tritium measured in the pretraps Data for this experiment are summarized in Tables 53 and 54
An exhaustive analysis of the analytical and sampling aspects of these data is not warranted at this time since several variables which affect the addition sampling and the tritium losses have not yet been established A general discussion on the oehavior of tritium in the CSTF is given elsewhere1 The preliminary data are sufshyficiently encouraging to merit a more extensive investishygation into the extent and mechanism of tritium intershyaction with sal and cover-gas components Plans are now under way to monitor the tritium diffusion through a portion of the loop wall and to measure the level of active protons in the salt during addition of tritium A more intricate bull over-gas sampling device (a probe designed for the sart monitoring vessel or salt sample port) is being considered and may be fabricated if no simpler solution to the gas sampling problems can be found
3 Reference Sect 112 thn report
47
TaUeS3 Jiitmtm content in cover-gas amahs after jtvoad tritium aMinoa
mCSTF
Tricium m ja D l l e rime laquopCimll
(AlKWM) HOvi luhk HcmenuJ
5 0730 96 o5 ltmraquo HO 2 2 1130 22oo 10 1330 5JWgt 20 1530 7500 27 1830 13000 34 1920 13000 39 2100 12000 40 2315 9300 39
6 laquoP3n 9300 2 I I mi ltraquo) 16 1500 6500 i4 2000 4700 10
7 0940 3300 68 1415 2400 49
O93o ltraquo00 34 9 1450 1600 52 to W40 1300 2 1 1230 900 2 J 12 1010 570 11 13 1010 23o 0 15 inoo 1X2 lO llaquo iraquo935 76 05 21 1010 73 o j
TaMr 54 Tribmn content m sak s a f k i after moan H i r i mdash aaditioa m CSTT
Dale Sample Trunin iAapnU No m lad-e l
4 5 1313 nraquo 5 59 (1954 90
60 1145 21 61 1350 36 62 IS4ft 52 A3 IX4X 7 | 64 1932 6ft 65 2125 71 66 2335 50
6 67 lift in 30 6ft 157 19 A9 2 lraquo 16
7 To IOI4 9 5 71 152 ft 1
T 1 lolft 36 9 73 0916 4 2 I I 74 124ft 39 12 75 1035 14 13 76 I04K ^ 1
15 77 IOIO 14 I I I 7raquo IOIO 07 21 SMV IOA l3fW o5
5 3 ELECTOOANALYT1CAL STUDIES OF IRON II) IN MOLTEN LiF-BeFj-TkFlaquo
(72-16-12 MOLE 9tgt
D L Manning G Mamantov
Electroanalytical studies in molten fluorides have particular importance tor possible use as in-line analytishycal methods for molten-salt reactor streams Irani II) is a corrosion product present in molten-sIi reactor fuels We have previously carried out electrochemical s tud ies of i r on ( l l ) in molten LiF-NaF-KF ( 4 6 5 - 1 1 - 5 - 4 2 0 mole L iF -BeF 2 -Z rF 4
(696-254-50 mole ) and NaBFlaquo-NaF (92-8 mole ) Since the fuel solvent for the MSBR is a thorium-containing salt LiF-BeF ThF 4 (72-16-12 mole )it is of interest to conduct vortasnmetnc and chronopotenti-ometric studies of irondl) in this fuel solvent To detershymine concentration andor diffusion coefficients by linear sweep voliammetry it is necessary to know whether the product of the electrochemical reaction is soluble or insoluble The measurements discussed bdow were dace with this purpose in mind
A volummogram showing the reduction of ironOU Fe2 -raquo Fe at a gold electrode is shown in Fig 54 The circles represent the theoretical shape based on current functions tabulated by Nicholson and Sham for reversible wave where both the oxidized and reduced forms of the electroacthre species are soluble Thus even though Fe2 is reduced to the metal at gold the electrode reaction very closely approximates the soluble-product case apparently through the forrmtion of iron-gold surface alloys Further evidence that the Fe3 - Fe electrode reaction at gold conforms to the soluble product case is illustrated by the chronopotenti-ograms in Fig 55 The ratio of the forward to reverse transition limes ir^r) compares favorably with the
4 D L Mannmc Votcaninernx- Sradaroif Iron m Molten Lif-Nar--Kr fVermwwj Chen 6 2 2 7 i | 9 6 3 l
5 D I Mannine and G Manunfti X j p d San Voium-metric jnd CrirraquonnjgtotentKgtroeirraquo Sludirt igtf Iron in Molten H w r e k W tleclmtntl Oirm 7102 H964raquo
6 I I W Jenknu D I Manmae and O MamantoT Flec-irnde fotentiaU of Several Redlaquo Conple in Mollcn Hno-rnfeO Nmntchrm Sgth 1171 S3 119701
7 f R Clayton it HeciiochemK-jJ Slwbe in Molten Hnoride and Fraorntmrawv doctoral dtunalnm Imvenm of Tenncvee December 197) p ft2
ft A S Meyer et j l MSft Program WniMwn rop Rep Aug M 9 T 4 ORNl-laquo72Xp 44
9 R S Nicholson and I Sham Theory of Stationary FKtrode foiarocraphy J Oitm 3 7 0 7 I | 9 O I
48
QWNL-PWG 75-11275
I I I I I I I 150 tOO 5 0 0 - 5 0 -WO -150
POTENTIAL mV
Fy- 54 Stationary electrode watamumapam for e refacshytion of r V af gt faM electrode bull Broken UF-ueF-TnF Po-lentil axis B ltf - poundbullraquo-- Solid line is experimental Circles are theoretical dupe lor soluble product Iron) III concentration 0027 f electrode area 025 cm s lemperature 650 C
theoretical value of 3 (ret 10) for the soluble case which again points to the formation of surface alloys
The reduction of Fe2 at a pyrolytic graphite elecshytrode is illustrated by the vultammogram in Fig 56 and the chronopotentiograms shown in Fig 57 For the reversible deposition of an insoluble substance where n = 2 the voltammetrk Ep - pound p I = 303 mV at 650degC (ref II ) is in good agreement with the experimental value The chrooopotentiometric ratio (zyrr) is approxshyimately unity which also h indicative that Fe2 is reduced to metallic iron without any apparent interacshytion with the pyrotytic graphite and that all the iron is stripped from the electrode upon current reversal Therefore iron appears to be reversibly reduced to a soluble form at gold and to an insoluble material at pyrolytic graphite Thus the effect of electrode subshystrate on an electrochemical reaction is illustrated by this example
Chronopotentiograms for the reduction of Fe2 at an iridium electrode at 518 and 60DdegC are shown in Fig 5 8 The ratio at S I8degC is approximately unity and is 3 at 600 a C which is evidence that Fe1 reduction at iridium approximates the insoluble-species case (as with pyrotytk graphite) at SI8degC and the soluble-product case (as with gold) at 600degC This change in reduction behavior with temperature was not as pronounced at gold or at pyrolytic graphite
10 W H RimjnMn Oirowopoecmwiweiiic Transition Times and The Interpretation^W Chem 321514 (l0gt
11 C MwuMm D L Manm and J M Dale Reversshyible Drpnsitrxi of Metal on SoM Electrode by Voflammetry wnb Linearly Vary in Potential tlrctntml Ckem 9 253 tl9raquo5gt
The chronopotentiometric transition time r for an ekctroactiw species is given by the Sand equation 2
Average diffusion coefficients oi Fe2 in this melt evalushyated from the chronopotemiometric measurements by means of the Sand equation are approximately 42 X 1 0 80 X 10 and 15 X I0 5 o n 2 sec at 5IX 600 and 7O0degC respectively
54 VOLTAMMETRIC STUDIES OF TELLURIUM IN MOLTEN UF BeFThF 4
(72-16-12 MOLE )
D L Manning A S Meyer G Mamantov
Tellurium occurs in nuclear reactors as a fission prodshyuct and results in shallow intergranular cracking in structural metals and alloys i It is of interest to charshyacterize this substance electrodiemicaliy and ascertain the feasibility of in situ measurements by eiectroana-lytical means We previously14 carried out preliminary polarization measurements at a small tellurmin poc1
electrode in molten LiF-BeFj-ZrF to estaampbh (he potentials at which tellurium is oxidized and reduced in the molten fluoride environment These preliminary observations indicated that the electrode reactions are complex
For tellurium screening studies J R Reiser of the Metals and Ceramics Division fabricated an experishymental cell equipped with viewing ports and electrode ports for studying the stability of lithium teUuride LijTe in molten LiF-BeF-ThF4 The Li2Te was added as pellets following which voUammograms were reshycorded at gold and iridium electrodes
As LsTe was added to the melt the voliammograms became com4ex and are not yet completely undershystood For clarity pertinent observations at the iridium and gold electrodes are tabulated separately
1 Upon adding one 35-mg pellet of Li 2Te a reducshytion wave observed at 09 V vs the It quasueferencc electrode (ORE) disappeared- fhis wave is not yet
12 Pan Drlahay p 179 IT in Srw hturumenuH Mrlkodt m Eltcmxhrmotry htterscience New York 1964
I J H F McCoy Maiernh tor Salt-Tontammt Veswlsand Pipmt The Dtvrktpmtni mtd Vlaquoftn of Mollrn-Sali Rnclon OftNMH|2ll-ebnary 1975raquop 207
14 A S Meyer el j | JW hnmm Stmmmmi Prop Rrp Aug SI 1974 ORNL-5011 p 42
49 ORL-0G 7S-M277
OWEVT TiME CURRENT TIME n l tslaquocdraquo) (mA) (stcdw)
5 J Cyclic ibroouyofcplimi mdash i for w wountioa of bulloa j l l ) at a f o M efcinuiat Foraufciy of troMllt X15ttecti ode jrcj
identined The pellets did not melt or dissolve immedishyately Relics ot the pellets could be seen on the surface tor several days The windows of the viewpcris became coated with a bluish-fray deposit after a few days making viewing of the melt impossible The bluish-pay deposit is believed to be tellurium metal Tim indicates that tellurium species added as L i Te are not stable in the melt
2 Voltammograms recorded in molten LiF-BeF -ThFlaquo after additions ot Li Te did not reveal any waves that could be attributed to soluble dectroactive tellushyrium species Chemical analysis indicated lt5 ppm Te in the melt
3 Abo at an indium electrode a reduction wave was observed at 045 V vs the Ir ORE which was reasonshyably well defined at a scan rate of 002 V sec This wave is due to Cr J reduction the wave height increased upon adding CrF 2 but did not change upon adding LijTe At our normal scan rate of 01 V sec the wave was not well defined which explains in part why it was not positively identified on background scans that are norshymally recorded at 01 V sec
4 Voitammetrk waves indicative of leilunde firms on a gold electrode were observed However these waves disappeared after adding CrFj to the melt The volt-ammogramlt recorded at gold foflowmg the L i 2 Te addishytions became complex and the electrode reactions are not yet resolved
Additional volrammeirr measurements are planned whereby the supposedly more soluble and stable LtTe species will be added to the fuel melt
igt 2$ c m 2 temperature M W C potential io le wilts s Ir QRF
ORNL-DWG75-11276
l _ _ J I I 1 bull 0025 0 -0025 POTENTIAL V vs U ORE
fSA Statpmry laquofctWodc to l lmdashuupaw for IW rwJt-timi of imKl l ) at a bullyrorytic gray laquonlaquouut InwfoMe prodshyuct j i 650 ( ibrnretH-jl Kp hbdquoi - 05 mV me-i-uired 3 0 mV InHMlll ctgtiraquocenirjiHgtn n02 electrode jrea 01 o n
so
C---+C S -raquoTS
TMpound
F-f57 Cycfc Hraquoi-o-i--uli bull gt bull y mdash l fat HJC rofactioti of mottlU M raquo etcmgt4e area 01 cm 1 -cmr-mare 650C potcnlbi - o k tuli VI Ir URF
-TIME
FomuiilT ot irondh iraquoiraquo
vt
w i l l
Ffc SJ Cydm ctmomtfottmtia^mm for r jrra n2 a n 1 po-rnlnl laquoale raquonltlaquo v Ir QRF
ft- bull v -
r of MMdl ) at i Formality of -rolaquo(llgt OfMVrfcctr-i-Jr
Part 3 Materials Development H fe McCoy
The main thrust of the mateiials program is the develshyopment of a structural material for (he MSBR primary ciicuit which has adequate resistance to embrittlemeni by neutron irradmion and (o shallow intergranular attack by fission product penetration A modified Hasteiloy N conoining 2^ Ti has good resistance to irradiation embnukment however it remains to be shown that the alloy has sufficient resistance to shallow intergranular cracking Numerous laboratory tests are in progress (o answer (his important question It may be necessary 10 further modify (he alloy with rare-earth niobium or higher chromium additions (o impait heller resistance (gt shallow intergranular cracking
Laboratory programs (o study Hasteiloy N salt tellurium interactions are being established including the development of methods for exposing (est mat era Is under simulated reactor operating conditions Surface-analysis capabilities have oeen improved so that the reaction products in (he affected grain boundaries can be identified
The procurement of products from two commercial hea(s 1000 and 10000 lb I of 2^ Ti modified Hasielloy N continued All products except seamless
tubing were received and much experience was gained in (he fabrication of She new alloy The products will be used in all phases of (he materials program
The work on chemical processing materials is concenshytrated on graphite Capsule tests are in progress to study possible ch-mical interactions between graphite and bismuth-lithium solutions and to evaluate (he mechanishycal intrusion of these solutions into the graphite Since (he solubility of graphite in bismuth-lithium solutions appears to increase with increasing lithium concentrashytion a molybdenum thermal-convection loop that conshytained graphite specimens was run to study mass transshyfer in a Bi 25 Li solution
Some of the effort during this reporting period was expended in reestablishing test facilities Four thermal-convection loops are in operation in the new loop facility which will accommodate at least ten loops The mechanical properly and general test facility is partially operational but numerous test fixtures remain to be assembled and tests started An air lock has been added to the general test facility to make it more functional and plans were developed partially for further expanshysion of the faclity
51
(x Development of Modifk-d Ha^tclkn N H t McCoy
The purpose of this program is the development of metallic structural material)) for an MSBR The current emphasis is on the development of a material for the primary circuit which is the must important problem at present The material for the primary- circuit will be exposed to a modest thermal-neutron flux and to fuel salt that contains fission products It is believed that a modification ot standard Hasteiloy N will be a satisfacshytory material for this application An alloy that contains y1 Ti appears to adequately resist irradiation embrittle-ment but it remains to be demonstrated that the alloy satisfactorily resists shallow intergranuiar attack by the fission product tellurium Small additions of niobium and rare earths (eg cerium lanthanum) to the alloy abo improve the resistance to shallow intergranuiar cracking and likely will not reduce the beneficial effect of titanium in reducing neutron embrittlement Increasshying the chromium concentration from the present 7T to a value in the range of 12 to 15 may also be beneficial in preventing shallow intergranuiar attack Currently factors associated with production of the 2T Ti modified alloy in commercial quantities are being studied while smaller be-ts raquoe being nude o( Hasteiloy N containing both 2 r Ti and additions of niobium and rare earths These materials are being evaluated in several ways
Two large heats one 10000 lb and the other 8000 lb of the ya Ti modified alloy have been melted by a commercial vendor Product shapes including plate bar and wire have been obtained for use in several areas of the alloy development program Tubing is currently being produced by two independent routes The various product forms from the two large heats are being used to fabricate the salt-contacting portions of two forced-circulation loops
Laboratory methods for studying Hasteiloy N salt tellurium reactions are under development Methods must be developed for exposing candidate structural materials to simulated reactor operating conditions Tests are being run in which specimens are exposed at 700V to the low partial pressure of tellurium vapor in equilibrium with tellurium metal at J00C Other tests involve metal idlundes thai are either added to salt or scaled in cvjcualed quart vus lo provide a source of tellurium Several experimental alloys have been exshyposed lo tellurium and Die extent of inlergranular cMltking was evaluated meiallograpliically hssenli^l In tins prltgram jrc attentate technique for identifying
and characterizing the reaction products Several methods for the analysis of surface layers are under development
Materials that are found to resist shallow intcrcranuiai cracking in laboratory tests will he exposed laquobull fissioning salt in the Oak Ridge Research Reactor TeGen fueled-capsule series Three materials (standard llastelloy Inconel 601 and type 304 stainless steel) were exposed in this manner during the first TeGen experiment and their cracking tendencies closely parallel those noted in laboratory tests in which these materials were exposed to tellurium vapor Fuel pins for a second experiment have been filled with salt containing gt J U and will be irradiated in the i a future
61 DEVELOPMENT OF A MOLTEN-SALT TEST FACILITY
H E McCoy K W Boling B McNabb T K Roche J C Feltner
When the MSRP was terminated early in 1gt73 most of the equipment was reassigned to active programs When the MSRP was reactivated a year later the conshystruction and installation of new equipment were necesshysary before testing could begin Balding 2011 acquired by moving the occupants into a siraquoaller building had been used as a mechanical testing area about 12 years previously and was already equipped with emergency power and air conditioning However numengtus imshyprovements ~n the building were necessary in addition to lb acquisition and placement of new equipment Although all of the equipment is not operational this report will describe the status of the facility
The building is a two-story structure with mnninal dimensions of 50 X 50 It The first floor is quite thick and more suitable for -mourning vibration-sensiiive test equipment The second floor is of lighter capacity and is more useful for offices and supoort activities There are Iwo stairways leadmg lo the second floor hut all heavy-items must he brought up hv an overhead crane which extends from the west side of the building The west wall had deteriorated and large doors leading into llie first-floor experimental area made close temperature control almost impossible An air lock having the dimensions 10 X W ft was added lo the west side of the building which greatly increased the buildings usefulshyness for experimental work An inoperabk emerge- puwei geneialor located in a small building on the cast
52
5
side or Building 2011 Mas removed and the space renovated to provide a small shop area
Figure 61 is a photograph of the west side of Building 2011 The air lock which was added is visible on the left-lurid side The crane lor transposing materials to the second f raquo)t is alsigt shown Figure b2 is a view of tllaquoe north side (ias storage racks the new emergency power generator and tie small shop area I left sulci are evident
Figure raquo slows the equipment layout tor the first floor Some of the equipment in the southwest owne is used by the Analytical Chemistry Division lor detershymining the concentration of oxygen in liquid-metal samples A neutron generator is located beneath the salt storage ar a and is used for oxide activation analyses This analytical capability is quite unique and will likely be maintained The 14 lever-arm creep machines on the north side aie for testing in an air environment the 8 machines in ihe next row are for testing in a sail envishyronment the Ji machines in the next row are lor testing bulln an air envirorment Five strain cycle machines are located in the southeast corner and will operate with
test specimens in j salt enviroiiVrctii Ihe temperature and strain readout equipment is centrally located Sail storage tjclitie and salt charging equipment are used ut conjunctii-n with he tests operating in salt environshyment S
The equipment layout on the second floor is shown m Fig o4 Six deui-Ioad creep machines for testing in an air environment are located on the south wall- The tube-hurst equipment is only partially instiled and lis installation is not considered a high-prioritv item Tie annealing facility consists of en furnaces having vartcux temperature and envingtnmental capabilities A separate laboratory in the northwest corner is used for experishyments involving tellurium llasieiloy N interaciiiws The other facilities on the second floor include offices a data storage and processing area an instrument repair shop and general storage
A view of iome of the 22 lever-arm creep machines for testing in an JH ermionmeni is shown tn l-ig t o and a cl-raquoeup is shmn in Fig traquofraquo All of these machines are in operation The control cabinet shown in Fig istraquo contains tlie insirunteKistion for two creep machine-
Photo 22SC-7S
yen 61 Mollrft-SjH Teraquol Faculty (RmMiof 2011) (mm Ihc wta ale The newly tiHUtrihled Jit lock bulllaquo mi the left
54
iJf JhZ
^bullyr^J^f1
Fifc J Matae-S TMI Ficttljr (Baliinj 2911) fjoraquo the monk ate Feature of interei include the hop area on he tt~ left the emenBencv pronator on the kft o s Morale rack in the center and the newly constructed air lock on the ri$h
iraquo now
I if(raquoraquo Kquipmcm layout for the fir floor of BudJinf ifll I
55
Fig fc4 EqnpncM Iqroat for Ifce Miomd Onor of IwMMg 2011
The frame is of welded steel construction The levei arms have two sets of knife-edge pivots vgt that the weight on the back of the arm is multiplied by factors of 6 or 12 The pull rods and cxlcnsometcrs are curshyrently arranged for testing small specimens having gage dimensions 1 in long by lA in in diameter Pull rods and cxtcnsomctcrs lor larger specimens required for code testing) were also fabricated and can be used in the same machines
The specimen deformation can he determined by the dial gage or by a transducer which measures the deflecshytion of the dial gage shaft This transducer signal is conshyverted to a dc signal by the instrumentation in the bottom of the control cabinet cm the right (Fig 66) and is printed at another location The electronic circuit will also accommodate averaging transducers which will be used on more precise code work The instrumentashytion in the bottom of the control cabinet also has a module for measuring load from a load cell (not shown) which Tils in the bottom on (he creep machine The specimen is heated by a resistance-wound furnace
having a maximum Icmpcraturc capability of I200C The temperature is measured by up to four Chromel-Alumd plusmni accuracy) thermocouples treated at various positions on the ipcimcn gage kngth The signal fron one of these thermocouples is used by the Leeds and Northrup type KO proportioning controller to control the furnace temperature Switches within this unit activate an alarm shown in the upper left coiner of the control cabinet (Fig 66) if the temperature varies more than plusmn6degC from the control temperature This alarm unit activates a local light and bell alarm as well as causing an alarm t gt sound in the Shift Operations Office A second thermocouple is tied to an over temperature monitor (lower left side of control cabinet in Fig 66) This monitor is set 10 to I5degC above the control icmp-rraturc arid will interrupt power to the furnace The monitor must be reset manually The furnace is powered by a solid-slate power supply deshysigned by T Hulton of the Instrumentation and Conshytrols Division The unit incorporates a digital Variac which allows power settings of 0 10 25 SO 75 and
56
FlaquofcS i t f
100 of line voltage Power is pulsed through the unit as called for by the Leeds and Northrop controller
The six dead-load creep machines on the second floor are quite similar to the lever-arm creep machines just described As shown in Fig 6 7 these machines r e not in operation but the construction work is com| iete Since the load is applied directly to the bottom of the specimen the equipment is limited to specimen stresses of about 20000 psi However the frames can be conshyverted to the lever-arm type
Two salt environment creep machines are shown in Fig 68 The frames and control instrumentation are the same as for the air environment machines shown in Fig 66 The primary modification is a stress unit which can be immersed in salt Four load-bearing rods run from the bottom of the specimen to a flange near the top of the frame A rod from the lever arm passes through a seal in the flange to the top of the specimen Thus weights placed on the back of the lever arm place the specimen under tensile stress with the pulling force being transferred back to the flange No rods protrude
far below the bottom of the specimen and a salt conshytainer can easily slip over the stress unit This container seals against the underside of the flange Extensometer rods for measuring the strain pass through seals in the flange and strain can either be measured by a dial gage or a transducer A 4-rn-diam furnace fits over the salt container There arc several openings through the flange into the container for gas lirtes and ball valves for elecshytrochemical probes and for making additions to the salt Figure 6deg shows the salt-creep machine which is in sershyvice The salt raquoas transferred into the pot on the right in the salt preparation facility at Y-12 The transfer pot was placed in a furnace after which the transfer pot and the receiver vessel were heated to about 600degC before the salt was transferred by applying argon pressure to the transfer pot The temperature was stabilized in the creep chamber and a strejs was applied to the test specshyimen
One of the five strain-cycle units is shown in Fig 610 The test specimen is a l-in-OD tube with a reshyduced gage section having a length of I in The tube is
57
Flaquo 6A CkMtmp of two Mr-
welded in place and stressed by a rod which extends from the bottom of the specimen to a piston above the specimen The piston s moved by applying air pressure to either side resulting in a tensile or compressive force on the specimen The specimen assembly is immersed in salt while it is being stressed Extensomeier rods extend through the top flange to measure the strain These rods move transducers whose signals are recorded on the bottom instrument Switches inside the recorder can be
adjusted to change the stress from tensile to compresshysive when the strain reaches certain values The test can also be controlled on a time basis and the strain reshycorded Other modes of control are also possible This type of test is to study the rate of crack propagation through thin-walled tubes of varying composition in the presence of tellurium Installation of the equipment has been completed and test specimens are welded in place The tests will be started as manpower becomes avail-
raquo
ask Thear mdashaAntv war be ased for aftojr and ame precise work w be done oa MTS e war arm to be procared at a later dale
The anai jau colectioa station h oa fLe first lloor (Fig 611raquo The apper part of the cabiaet OR die left cuMtaatt snitches a aiaiial readoat aad a snaje poiat recorder lor leraperatnres from avow one-third of dK machiaes- The haak of Mriicbes ia the top of da rajfct-haad cabinet is for tetecrinc siraia rawerraquo for each
The sna-i tcadaajs faaa each auduae arc priated oat oa oae of the andtipoiai recorders A data
M I is located m the aaodfc of the right-I cabiaet Has rnsmMKM ltai print oat 100 points
oa dK designated Ireqneacy (asaaly I br) This is snf-fcieat capacity to print oat oae teaaperaiare aad one
for each piece of eqai|aarnt Two orjer bulleasnriag stations are located elsewhere on
dK first floor
Ffct7 General
59
The annealing arez sun the second floor I Fig 612) The two furnaces on the lower level have environmental control and are used for short-term anneals Eight other furnaces are used for long-term anneals hi which the samples are encapsnlated
Figure 613 shows a typical area in tne second-floor laboratory wed for tdurtum-HasteBoy N studies The
equipwunt includes a quartz encapsulation apparatus special gradient furnaces for annealing the capsules equipment for measunng gas-metal reaction rates and a general-purpose hood
The ttthe-burst equipment boa die second floor (Fig 614) There are nine test stations with each station
four test |
Fin 68 Close-up of two bullut-eiwuuinwtnt lever-arm creep machines The salt chamber on the left-hand machine seals apinst the horizontal flange and the furnace n raised a proportionate distance The temperature control and strain-measurement instrumentashytion are shown on both sides of the creep machines
60
Ffe 69 Lever-arm jd l imnunmiiit creep NMCJMMS in operation The ult chamber and furnace have been raised calt as transferred by argon pressure from the vessel on the right into the test chamber The cabinet on the left contains switching and temperature readout instrumentation for several creep machines
61
FlaquoIO ChwMip of a a l l ltngtJKinmml strain cycle machine M l amocMni intfnjmvntation The ieraquoi specimen is a l-m-diam lube welded on I he bottom I a rod and un ihe lop to a heavy-walled lube The rod passes through the lube and alicrnaling tensile and compressive stresses are impigtsed on the specimen by ihe actuator (piston-cylinder combination) The instrumentation is used to control and record the sires strain-time history
bull2
F g 61 I The cabmct on Ike left is one of smraf tartowt stations for limptnmn Chrontd-Alumel sensors from seYeral creep machines arc ran to this cabinet The switches make it possible to read each thermocouple individually on the digital unit at tlie lop of the cabinet One point at a lime can be recorded on the Azar recorder The cabinet on the right contains a data logging unit for recording strain and temperature on all the machines on the first door The three recorders in the bottoms of the two cabinets record strain data from a l machines
a
fit- 612 tkotopajk of hcsMltsaag facfvty The two lower furnaces have com roikd argon environments Fighl other furnaces (al noi visible) have air environments and are used for long-lime anneals
64
Fig raquo13- Typical vie of geaoat-aeaaot used to dean salt from jpuiawai tested in a l t amroameati
ettl reactroas The hood on the left is
rraquoraquoiraquo wraquo-raquo
F|g 614 General view of tube-burst testing eqaipment asai lo stress tabular spec ant ni by internal pre ware The front paneli contain only (he pressure-related equipment The furnaces where the test specimens ate located and their associated control instrumentation are behind the pressure panels
65
by a pump with a wear pressure of 14400 pa The pump aad the ass-xiated reservoir cylinders have beea approved for opcratioa aad the iaawaaal test suborn w2l be pat irt semcr oa c ow-pnonty basis
Iiiaatdun efiptens wtfJ be placed oa geinaf a l equipment iato operatioa Longer-term objectives war iadade prucaremeat aad iastaaatioa of an MTS fatigue machine aad possible expansion of the fast floor to accooaaodaie additioaal creep machines
t J PROOJKEMENT AND FAMUCATION OF EXHHMENTAL ALLOYS
T K Roche R E McDonald B McNabb J C Fehaer
bullUI hadwit iaaHeatsafraquo Ti M I T I I I M H I I J N
One of the more promising alloys at present for the primary circuit of an MSBR is 25 Ti modified Hasidloy N Progress has been made in the scale-up of this alloy with the production of two large heats one 10000 lb and the other 8000 lb by a commercial vendor The analysis of the heats was reported preshyviously These heals were used to establish processing parameters for producing plate bar and wire and more recently emphasis has been placed on processing seamshyless tubing Mill products from these heats are being tesed in the general alloy development program and used in the construction of two forced-circulation loops for studying the compatibility of the alloy with fuel salt
As reported previously several fabrication problems were encountered with the first heat (heat 2810-4-7901 or 74-901 10000 lb) in that it was prone to cracking during hot-working operations particularly during hot rolling of the plate However with the aid of Glcebli evaluation tests which defined the hot-working temperashyture range of the heat to be between 1090 and I I77degC plate products were successfully rolled A second prob-leri was the susceptibility of the heat to cracking during the annealing treatment following cold drawing in the production of bar and wire products This problem was partially solved by cither flexing the drawn product in straightening equipment prior to aiiiltjHijat 1 7degC or by lowering the intermediate annealing temperature to nidegc
Because a considerable amount of the first heat wis consumed in establishing processing parameters a
I T K Roche B McNabb and I C FeltrwrMSK Proshygram Semmrmu Pmgr Rep Feb 2 1975 ORNL-5047 pp 60 63
second heal was prodaced (hat 8918-5-7421 or 7S42I 8000 lb) for coavcrsioa to tatang bar and wire The bot-forgaag behavior of das heat was qaite good as confirmed by Cfeebie data which showed a very broad bot-workmg temperature range of 930 to 12600 Approximately one-half of das heat was forged and tamed to 4 Jna-diara bar for coaversion to seamshyless tubmg by the vendor Akoa forged bar 4 X 4 X 6 0 in was produced for conversion so tabiag by an altershynate route The balance of draquoe heat was convened to the folounac products which bat been received o-m-diam bar (630 lb) 05-ai-diaai bar (292 ft) 0J12-in-disn bar (996 ft) 0125-av-diaai wire (405 b) and 0-094-in-diam wire (338 lb)
For making products in the range ^-ia-diam bar through -in--diam wire forged bar was hot roBed to about I-ia-diam bar and an attempt was nude to conshyvert this material by cold drawing to final sizes with intermediate annealing treatments This routing proved satisfactory unti a H^meter of 0J95 in was reached but annealing cracks as experienced with heat 74-901 were encountered to some degree during processing of the 03l2-tn-diam bar and the wire products For example during a run involving about 850 lb of stock about 2 of the product was lost due to cracking during annealing after the material was drawn from 0J95 in in diameter to 0 J i 2 in in diameter The bar was mechanishycally flexed prior to annealing a technique used to minimize cracking in material from the first production heat of the alloy (heat 74-901) The annealing cracks were observed to run parallel to the longitudinal axis of the bar Examination of a transverse section of the cracked 0Jl2-in-diam stock showed that the cracks were intergranular in nature and up to 0065 in deep in the section examined (Fig 615)
It has been possible to reproduce the annealing crack phenomenon on a laboratory scale Samples of 05-in-d am bar of each of the two production heats were coiJ drawn lo 0395 in in diameter (37 reducshytion) and annealed at I I77degC Heat 74-901 developed longitudinal cracks heat 75-421 did not These results are consistent with the vendors observation that heat 74-901 is more susceptible to the cracking problem Since the cracking can be reproduced or a laboratory scale it may be possible to more fully characterize the problem and define fabrication parameters necessary for its prevention
Of the two routes being pursued for the procurement of seamless tubing one by the commercial vendor inshyvolves trepanning forged and turned bar slock to45-in OD X 05-in wall cold tube reducing (or pilgering) the material in three steps to 20-in OD X 0187-ir wall
66
m
o p A
-O o_ b
o x t o 1 yraquo2
o o-
8-o
yen $ H m d i raquo cocks iraquo ttJU-aL-MMi bat of 2raquo T t - a o M M KasMftty N (hut 75-421) Bar was coM drawn 37- and ameafcd a( I065C Ftdicd with (dyccm rrpa 50x
followed by cold drawing to final sues of 10- 075- 05- and 0J77-in OD X OJ035- to OX)72-in wall This route for tubing production depends upon the efforts of two other vendors one for trepanning the bar and the other for drawing to tlnal sizes The trepanning operashytion has been competed and resulted in six tube holshylows each approximately 6 ft long Each of these pieces was processed through the first tube reducing pass to a 375-in OD X OJ75-in wall (3675 reduction) with no difficulty From this point work was confined to one tube hollow to determine its response to in-process annealing at I I 2 I degC and water quenching followed by further tube reduction Annealing of the hollow beshytween each tube reducing operation was preceded by the annealing of a sample which was then liquid penetrant inspected to determine any evidence of crackshying With this procedure the hollow was taken through the remaining two tube reducing steps and three annealshying treatments with no major problems A few shallow surface flaws did develop but these were readily condishytioned from the product Therefore on hand at present is approximately 24 ft of 20-in-OD X OI87-in-wall stock which will be scheduled with the redraw vendor for processing to final sizes The lube reduction of the remaining five hollows will also proceed
The second route for obtaining seamless tubing inshyvolves hot extrusion of tube shells at ORNL followed by cold drawing to size by an outside source Starting stock was the forged bar of the alloy 4 X 4 X 60 in (Fig 616) The bar was machined into six billets each of which measured 3deg50 in in OD by approximately 95 in long and had a 45 tapered nose for extrusion out of a 4060-in-diam press container through a conical die Two of the billets were drilled 0812 in in ID and four were drilled 10 in in ID to accommodate a mandrel and to allow for a slight variation in extrusion ratio A glass coating which was molten at the extrushysion temperature was applied to the billets and served as the primary lubricant Additional lubrication was provided by Fisk-604 grease that was applied to the tooling Five of the billets were extruded at 1200degC and one at I250degC Low extrusion rales (ram speeds) were used to prevent a sufficiently large temperature increase that the incipient meiing temperature of the alloy would be exceeded otherwise serious cracking could result This problem was encountered during the develshyopment of standard Hastelloy N but was solved by conshytrol of extrusion rate
The results of extruding the l7r Ti modified HaMclloy N billets in the order performed are pre-
67
sensed in Table ftI Fur the first three tube blanks produced extrusions lottf 104 and 1605) die low rale of extrusion caused mandrel taawre d w to ecev I I K healing vf the tooling However ike length of tube blanks obtained with various extrusion ratios and ram speeds suggested that the combination of tooling used lor extrustoR 1604 (extrusion ratio of deg41) with an extrusion speed approximaidy equal to that of extrushysion 1605 125 m sec) should produce a complete tube blank This was die case for extrusions I60K and I6QN In an attempt to reduce the force required to make these extrusions the final tube blank lexirusion 1611)
was extruded a a slightly higher temperature 12501 A rather long length ol good extrusion was obtamed but mandrel fanure agam occulted due to the low extrushysion speed
Visual inspectioK of die tube blanks showed die OO surfaces to be quite good as must rated m Hg 617 wfwch shows the lesdmg end of extrusions I60K and 160V O i dae other hand boroocopic examination ol the IDs by die outside vendor performing the redraw operation revealed flaws winch were subsequently removed by gun iriEing These flaws shown typically in Fig 618 a=e believed tc be caused by inadequate lubn-
m-n
Flaquo l seamless tuctnc
H r ( lt 4 gt M u i r K T i - i N (fecal 75-42 h Slock for ramm bwVt o produce
Tafefc-tl snd raridof n w Mask cxtrwOTMvav2t Timdashnodinnl Nattdby N (beat OTI8-5-Mll|(B
Fxtruuon Die diameter i in i
1603
1604
1605
i475
1625
1475
Mandrel dumcrrr
in)
K IruMt-n Rjm speed ratio (in laquo i i
Force ttonsi
Maximum Running itesuils
0813
JO
0812
114
94 I
1041
15
15
25
1230 l l l l Good 0D surface 22 m of tube blank extrusion before mandrel fadure
l6igt 1100 Good OD surface 45 in of tube Hank extrusion before mandrel fadure
12f0 12i Good Oigt suriacc 4raquo in of rube blank extrusiim before mandrel failure
1607 1625 10 941 Stalled operational error
1608 1625 10 941 36 12911 1290 Good Ol) surface 70 in lube Mank extrusion
1609 1625 10 941 36 1290 i290 Good OIgt surface 70 in tube blank extrusion
1611 1625 10 941 10 1000 900 Repeal of extrusion 1607 jtood OD surface 55 in of lube Hank extrusion before mandrel failure
Notes Container diam 4060 in hxtrunon temp 1200deg (except extrusion 1611 at I250C Lubrication class on billets f-isk-604 jcrease on tooling
68
nraquolaquo15M-79
M06
760 Fig 617 Tibr hlanfc exuasjom of 2 Ti-wdifM I fuWuj N (heal 75-421 These are ihc leading ends or the two extrusion
and were photographed in the as-extruded condition
O O-
O O-
O ho d
Fig 618 Typical defects M I the made diameter of extruded lobe Wanks o 7 Tr-modifod rlartcBoy N (heat 75-421) Longtludinal section Ffched wrlh glyceria rejtia tOOx
69
cation during extrusion Therefore several additional extrusions are planned to test ihis assumption and to evaluate other lubricants The bilets will be prepared from the 6-in-diam bar fabricated from the same comshymercial heat used for the previous bitten
The products of the six extrusions (Table 61) were sent to an outside vendor for redrawing to finished tubing More effort was required than anticipated due to several factors the conditioning required to dean up the surfaces of the extrusions experimentation with both plug and rod drawing techniques to establish a workable processing schedule and more frequent and longer intermediate annealing treatments than anticishypated for the alloy The vendor believes that a satisfacshytory drawing schedule has been developed and is proshyceeding with processing of the remaining extrusions The vendors preferred process involves rod drawing and sinking operations requiring about 18 to 2ttS deformashytion per pass with intermediate annealing treatments at I I77C followed by water quenching Quality control steps after each process step irJ-de light etching folshylowed by visual inspection of the OD and boroscopk inspection of the ID for defects It is believed that the yield of tubing from the redrawn ORNL extrusions will be sufficient for at least one of the two forced-circulation loops now under construction
A 6-tt length of cold-worked 075 m-OD X 0072-in-wall tubing was received as product from the development work required to establish a drawing schedule The tubing is being evaluated by nondestrucshytive techniques Liquid-peneirant inspection of the OD showed no defects Silicone rubber replication together with radiographic inspection indicated the presence of relatively shallow crackiike indications on the I D over a 4-ft length Meiallographic examination of a small sample from the did of the 6-ft section showed the defects to be J maximum of 0028 in deep The tube will be annealed and inspection will be repealed including examination by an eddy-current technique In view of the number of process variations to which the tube was subjected in developing a drawing schedule the quality of the OD and that of portions of the ID is encouraging
622 Seimprodlaquoctiontfeatsof2ri-Modified Hastdoy N CoiriaMng Niobium
To provide stock for a more complete characterizashytion of niobiunviiianium-modified Hastelloy N eight SO-lb heals and one 2S0C lb heat (Table 62) are being prepared by a commercial endor Niobium additions lo the 27 Ti modified Hasieloy N base arc of interest for enhancing resistance to tellurium embritilemcnt and
Bve Ni-12T Mo-7laquoS Cr-21 Ti-007 C
l ov Addition of the jadiciied rirMear 4) Heat
laquoze lltraquo
Jmr re Si Ma Nb
Heat laquoze lltraquo
i 10 01 02 085 -115 2500 10 01 02 04 06 50 IO 01 02 135 -165 50 10 01 02 18-22 50
30 50 01 02 085 11$ 50 10 01 - 02 02 085-115 50 10 01 02 05 085 115 50
8 30 50 01 02 02 -05 085-115 50 bull 10 01 02 085 115 50
Indrndnl nines denote maxnnom coaceMnrioa
niobium levels between 05 and 2 wt It w i l be investishygated Ir addition the compositions of four of the alloys were chosen to investigate different levels of the residual elements Fe Mn and Si These results will be important because of the beneficial effects of the residshyual elements upon oxidation resistance and will allow greater latitude in scrap recycle
The nine alloys have been melted and will be procshyessed lo products in the near future The eight 504b melts will be forged and rolled to ^-in-thkk plate approximately 4 in wide This material will be used for voidability salt corrosion tellurium compatibility and mechanic property tests The 2500-lb heat will be conshyverted to t |raquo- V - and | k-in-diam bar products and to a 4 X 4 in round-cornered square bar About half the material will he retained in the last form lo allow future capability for producing additional products of sheet bar and tubing
6 J WELDAMLITY OF COMMERCIAL ALLOYS OF MODIFIED HASTELLOY N
B McNabb H E McCoy T K Roche
Welding at ORNL is generally performed in accordshyance with Section IX of the ASME Boiler and Pressure Vessel Code2 Basically this requires that a procedure for welding a material (or class of similar materials) be developed and that welders demonstrate that they are qualified to weld by the procedure The procedure must
2 ASMt BoHer and Pressure Vessel Code Section IX Qutt ifuvxm Standard for Welding and Braimg Procedures Weldm Bnm end Welding and Brtittg Operators American Society of Mechanical Engineers New Ywk 1974
70
be a written document including die essential variables associated with making the weld and must be backed by test reports including bend and tensile tests which show that the weld is sound A welder can then be qualified to use die procedure by making a weld which is subshyjected to bend tests to show that it is sound This is a very suupKfied view of the process used to develop and maintain high welding standards and the ASME Boiler and Pressure Vessel Code Section IX 2 should be conshysulted for more detal The Plant and Equipment Divishysion main tains a weld test shop under the supervision of D R Frizzed to implement the process and this shop is frequently assisted by the Inspection Engineering Department
Procedures were previously developed for joining HasteHoy N to Hastdloy N (WPS-1402) and Hastettoy N to die austemtk stainless steels (WPS-2604) but it was necessary to demonstrate whether these procedures apply equally weO to 2 Ti-modified HasteBoy N Therefore K-n-thkk test plates of 2 Ti-modified Hastelloy N (vendors heat 2810-4-7901 designated ORNL heat 74-901) were prepared and welded as folshylows autogenous welds with 74-901 welJ wire welds with 2 Ti-modified Hastelloy N weld wire (vendors heat 8918-5-7421 designated ORNL heat 75-421 welds to standard Hastelloy N heat Nl5075 with 2 Ti-modified Hastdloy N heat 75-421 weld wire and welds of type 304 stainless steel heat 18024 with Inco 82T heat NX59I38-D wdd wire Each raquo d d was subshyjected to visual dye penetrant x-ray and metallo-graphic ixr^mation and to two tensile and four side-bend tests These tests were conducted in accordance with die ASME Boiler and Pressure Vessel Code Secshytion IX 2 and ail of the above-mentioned welds passed the tests The tensile specimens were machined from the test plates with the weld in the reduced-section gage length and were tested in a Baldwin tensile machine All Hastelloy N welds exceeded the required minimum 100000 psi ultimate tensile strength except the weld of 1 Ti-modified Hastdloy N to type 304 stainless steel which ruptured in the type 304 stainless steel base metal at 93300 psi The side-bend specimens were A X li X approx 8 in long with the weld in the center and were bent around a I-in radius in a guided bend fixture
The chemical analyses of the various materials involved are shown in Table 63 The side-bend specishymens are li in (luck X hi in wide bent around a l-in-radius mandrel in a guided bend test The specimens were macroetched in a solution of HO 20 HNOj -20 H 2 0 to delineate the weld and heat-affected zones Figure 619 u a macrophotograph of side-tnd specimens of standard Hastelloy N heat
N1-5075 Vi-in-thick plate welded with standard Hastelloy N wdd wire heat N I -S I0 I There were no fiows in the specimens after bending and visual dye penMrant x-ray and mrtallographic examination before bending showed that the welds were sound This weld was inde and tested to recertify the welder and to update the welding procedure specification Figure 620 is a reacTophotograph of side-bend specimens of 2 Ti-modified Hastelloy N (top) (heat 74-901) welded to standard Hastelloy N (bottom) (heat N1-5075) with 2 Ti-modified Hastelloy N (heat 75-421) weld wire by welding procedure specification WPS 1402 There were no flaws in the welds and the strain markings delineate the weld areas
Figure 621 is a macrophotograph of 2 Ti-modified Hastelloy N plates (heat 74-901) welded with 2 T i -modilied Hasteiloy N (heat 74-901) weld wire on weldshying procedure specification WPS 1402 There were no flaws in the welds and the specimens were macroetched to delineate the weld areas Figure 622 is a macro-photograph of the same heat of 2 Ti-modified HasteBoy N (74-901) welded with 2 Ti-modified Hastelloy N (heat 75-421) weld wire by specification WPS 1402 There were no flaws in the welds and the specimens Figure 623 is a macrophotograph of side-bend specimens of type 304 stainless steel K-in plate (heat 18024) (top) welded to 2 Ti-modified Hastdshyloy N (heat 74-901) (bottom) with Inco 82T (heat NX 59138-D) weld wire by welding procedure specification WPS 2604 There were no flavs in the welds and the specimens were macroetched to delineate the weld areas
Although special welding procedures were prepared for the joining of standard to 2 Ti-modified Hastelloy N with 2 Ti-modified Hastelloy N filler wire (WPS 1403) and for joining stainless steel to 2 T i - modified Hastdloy N with Inco 82T filler wire (WPS-2606) the parameters used in making these welds were identical to those used in procedures WPS 1402 and WPS-2604 developed for standard Hasteiloy N Thus we believe that the test wdds adequately demonstrate that stanshydard and 2 Ti modified Hastelloy N have equivalent welding characteristics and that procedures WPS 1402 and WPS 2604 can be used for both materials
Supplies of standard Hastelloy N weld wire were depleted over a period r f time and additional wire was purchased to the materials specifications MET-RM-304B However the voidability test was performed by O R N L Plates of standard Hastdloy N (heat 5067) IV t
X 4 X 10 in were welded with the new heat of weld wire from Teledyne Allvac (heat 9725) using welding procedure specification WPS 1402 and were accepted
71
Jiilln l i s i l
1 3
3 laquo m i a m I z
llllpl liillii s a = c e e v
i
i
I I I
Hill s s = s e
Ii2s I
I bull raquo bull
S C O
33 a c e o 3 O m
i
bull mdash copy o r- d 9gt
laquobullraquo bull gt ampgt ltlaquo rraquo laquo r i mdash
1 laquo
z z z
r t a laquo m r- f 2 gtgtilti bull laquor mdash H-
2 2
i ij
72
Ffcfc1 Bead N(heMNI-S075)j Htmuwwtt SIM)
Ffe gtJ0 I M 4 ffcciMtM of 2 T t - m o t f M HmHtoy N (fctrt 7901) art staataaJ H n M o r N (fcMNI-5075) j o M w M i Tt-modiTM Hartdoy N Mkr win (beat 75-421)
73
F laquo J I (heat 74401)
Ffe 622 ttmt (raquotat 75-421)
of J Ti-motfbJ HMcltoy N (beat 74401) f o M wMk 2 Ti-amtttM
74
FlaquoftJ3 i01 tyyc39v 3 I H T H N ( laquo laquo 7441) j IwMUTflkr
as passing all tests including one all-wdd-inetal tensile test and four side-bend tests with no flaws in the welds This material has been made available for general proshyject use
4 STAWLrTY OF VARIOUS MODIFIED HASTEIXOY N ALLOYS IN THE
UNIRRADIATED CONDITION
T K Roche H E McCoy J C Feltner
The stability of Nb- Ti- and Al-containing modified Hastelloy N with respect to intermetallic predpitation known as aging is being studied It is known that addishytions of these elements are desirable respeclivdy for enhancing resistance to tellurium-induced intergranular cracking for improving resistance to radiation embri-tlement and for deoxidizing the alloy during melting However beyond certain levds these dements can cause aging reactions by the predpitation of gamma prime |Nij(AITi)| or NijNb which in turn causes hardening or strengthening and loss of ductility Therefore studies are in progress for defining the amounts of Nb Ti and Al which can be added to Hastdloy N and still maintain a reasonable decree of stability The stabilities of a number of alloys including laboratory semiproduction and production heat having varying amounts of the
demenu in question are being determined by hardness tensile properties creep-rupture properties and micro-structural evaluation
The first approach to evaluating stability has been the determination of the room-temperature hardness of the various alloys before and after heat treatment at 650 704 and 800degC for periods up to 1000 hr The data for alloys held at these temperatures for 100 hr were reshyported previously1 and during the present period the 1000-hr data presented in Table 64 were obtained he data for alloys which show significant hardening relative to the as-annealed condition are Mocked off in the table
The hardness of the various alloys after a 1000-hr aging period follows the same pattern noted for the 100-hr aging period However the previously reported niobium concentrations of the niobium-containing alloys were low due to an analytical error the correct values are shown in Table 64 The present data show that with low aluminum concentrations (00S wt ) niobium contents approaching 2 (rather than as conduded earlier) can be tolerated in 2 Ti-modified
3 T K Roche D N Braski and J C Felfnrr MSK Pro-gum Semmnnu fmgr Rtp Feb 2S 197$ ORNL-5047 pp 71 76
75
lkra llaquoMi7WMri l
DatamMoriui hatdcMBg rcbthc to the
Icoaditiw
IoapoBtun (laquot ) Rockwell
Heat IoapoBtun (laquot )
AaaeaM (
Agt4 1000 were 704c
hr Nb Ti Al C AaaeaM
(
Agt4 1000 were 704c sooc
474-557 214 002 004 SI 5 S7S SSS S74 472-503 194 009 006 S44 S9S 882 891 474-901 IS 010 006 794 857 S63 856 471-114 1- 012 005 792 829 846 S44 427 24 0IS 0014 747 784 773 779 428 247 016 0064 S25 SS2 861 860 474-533 217 04S 005 Sl0 857 S62 849 474-534 209 053 008 893 925 904 909 429 24 0J5 0017 769 9 4 854 74 430 25
2J 034 074
0073 0016
SS6 7S6
1001 88 9 912 431
25 2J
034 074
0073 0016
SS6 7S6 978 984 928
432 048
235 19
069
008
0057 0037
874
SOI
1034 1034 974 425 048
235 19
069
008
0057 0037
874
SOI 841 858 852 421 10 19 007 0048 873 865 878 867 424 134 I S 010 0063 S84 902 SS9 904 418 192
190 20 18
005 015
0058 0055
891 S87
904 900 9IA
904 420
192 190
20 18
005 015
0058 0055
891 S87 1015_
900 9IA 913
435 142 23 015 004 886 1050 1021 903 43S 180 24 013 005 918 1066 1051 968 433 189 2 2 033 0024 848 1043 1021 881 434 186
252 2 bullgt
22 032 015
0061 005
933 931
1070 1088
103 8 1076
957 441
186 252
2 bullgt
22 032 015
0061 005
933 931
1070 1088
103 8 1076 1041
442 30 22 014 0052 950 1093 1096 1072 30 22 014 0052 950
Bavt Ni l2TMo K Cr l h r j | IMTC
Hastdloy N before aging occurs However the tolerance for niobium decreases with small increases in the titashynium and aluminum contents It must be emphasized thai the hardness data were obtained on unstressed specimens and that creep-rupture tests now under way indicate that lower concentrations of niobium are tolershyable when the alloys are subjected to stress These reshysults arc described Uter in this section
The effect of aging on room-temperature and elevzed-tempcralure tensile properties is being detershymined for most of the alloys Limited room-(emperalure results have been obtained after a 100-hr aging period at 650 and 800degC (Table 65) There is good correlation between the tensile data and the preshyviously reported hardness data As would be expected alloys which age harden during a given thermal treatshyment (data underlined in Table 65) also show an inshycrease in strength and a corresponding decreur in ducshytility relative to ihr solution-annealed condition
In the case of the tiunium-aluminum-modified Hastdloy N alloys the hardening phase is most likely gamma prime and this phase has been identified in heat 430 lt 25^ Ti + 034 Al) after 100 hr at 6 5 0 o C
Stress-rupture results for the titaniunvaluminum-modified Hasielloy N alloys at 650 and 704degC are shown in Tables 66 and 67 respectively Again there is very good correlation between age-hardening behavior as determined from short-term hardnlaquo data and the corresponding rupture life in the stress-rupture tests Abo the effect of temperature upon agmg an be seen by comparing the data sets for heats 429 and 430 at 650 and 704degC At the lower temperature both of these alloys hardened but neither hardened at 704degC Since hardening in these alloys is due primarily to the formashytion of gamma prime these results sugges that the gamma prime solvus temperature is located between 650 and 704degC for these two alloys This observation and the other aging data in Tables 6465 and 66 were
76
Tak6-5 raquo i m l all l i l i h t i i i i i i fci iwfNJ-TVAI
iicbtaKtodK
bdquo laquo t t m t ~ - - - StteaajbUO neat _ ^ _ ^ ^ _ _ _ _ _ _ ^ ^ ^ _ _ l o a a m _ ^ _ ^ _ _ _ _ _ Doaaaboa ()
iraquo r At c mum Y j - i ^ ^ 474401 18 010 00 AnwaM Ikr l 7 r c I MO 442 447 794
Aaoil00br50C 114 J $00 559 SIS Aged 100 brS00C I I9JO SI2 537 151
428 247 0 1 00 A a w a M l k t I I 7 T C 124 J 49-0 52 825 Aged 100 br50C 125J $0-5 527 M2 Aftd l0fgtbrS00C 1237 511 411 M7
430 2J 034 007 Aaneakdlbf I177C I2SJ $00 541 St Aac4IWbr5ltrc 1348 634 437 957 Aged 100 brS00C 12 J 531 $00 886
424 134 I a iO 00 AMtafcdlbr I177C 1372 527 512 Ago i00br6$OC 1385 52J 477 (93 Aged 100 brSO0C 1377 547 45S 199
435 142 23 015 004 Aaaeakd 1 hr 1I77C 12S4 510 54 raquo Aged 100 br50C 190 893 353 1025 Aged l00brSOOC 1339 54-5 S3S laquo73
442 30 22 014 003 Aantakd 1 hr II77C 1394 07 $42 Agadl00bf50C 1905 107 251 AftdlOObrSOCTC 144 ~ J 3 J 1 S 9
bull raquo Ni-12 Mo-7 O
TaMe64 St iwiaptmdashe data for wr iow beats of Nb-Tt-AI R M d M H a s t d b ^ N at 6500 aad 474) x I0gt pa
Heat Composition (wt gt Rupture
life (hrgt
Total strain
Are harden Heat
Nb Ti Al C
Rupture life (hrgt
Total strain at 650deg C
474-901 18 010 006 3950 270 No J74-533 217 048 005 4650 280 No 427 24 118 0014 866 217 No 428 247 016 0064 1150deg 73 No 429 24 03laquo 0017 9572 163 Yes 430 25 034 ftO^ 16980 73 Yes 431 2$ 074 0016 23090 101 Yes 432 235 069 0057 41710 21 Yes
42S 048 19 008 0037 14301 237 No 421 104 19 007 0048 20070J 73 No 424 134 18 010 0063 39530 65 No 418 192 20 005 0058 39550 32 No 420 190 18 015 0055 39510 19 Yes 433 189 22 033 0024 41690 10 Yes 434 186 22 032 0061 39550 09 Yes
BaseNi 12 Mo 7Cr Based on turdnest measurements on aged umircutd specimens Tesl still in progress Test discontinued prior to fracture
used to estimate the gamma prime solvus temperature boundaries at 650 and 704degC as a function of aluminum and titanium concentrations Alloys with compositions lying below the proposed boundaries in Fig 624 are stable at the indicated temperature and those above will precipitate gamma prime
With the addition of niobium to titanium-aluminum-modified Hastdloy N defining or predicting stable comshypositions becomes more complex There is evidence1
that mechanical stress significantly affects age hardening of these alloys which is not uncommon The room-temperature hardness data for annealed and aged specishymens of the various Nb-Ti-AI modified Hastdloy N alloys suggest a tolerance of about 2 Nb in a 27 Ti-0-5 Al modified Hastelioy N base (heat 418) beshyfore aging occurs Further increases in the aluminum niobium and titanium contents lead to age hardening at 650degC then at 70degC and finally as high as 8O0degC when the niobium content is increased to about 25 with 22 Ti and 015 Al (heat 441) If the broad assumption is made that the three elements are equally effective in promoting an age-hardening reaction and a plot is made of the total atomic percent of these deshyments (at Nb t Ti + Al) in the various alloys against the increase in hardness (^RBI caused from aging 1000 hr at 650degC a curve is obtained (Fig 625) A sharp break indicative of appreciable aging occurs between 3H and ^M at 1 (Nb + Ti + Al) Adding the variable of stress to aging response and plotting the parameter of minimum creep rate from creep tests at 650degC and 470 X I0 3 psi (Table 68) against total atomic percent (Nb bull Ti + Al) results in the curve shown in Fig 626 The break now is indicated between 2 and J at (Nb + Ti bull Al) The creep rale of alloys containing up to about 2 at rlt (Nb bull Ti + Al) is 15 to 30 X lO^ h t Three heats (70-835 6laquo-648 and 64gt-344) in the 2 to 3 at ^
region which are high in niobiuro and low in titanium are known to age upon creep testing at 650degC at d exhibit creep rates around 1 X 10Jhr One heat (425) with the reverse combination low in niobium and
4 H y McCoy MSK Program Senu4m1L ftogr Rep Feb 29 1972 ORNL-4782 pp 167-69
30
25
7s- i sm
20
z
z o u
15
10
05
NO y
bull704-C -
650 C
02 04 06 Al CUfTENT ()
08 10
F|laquo 624 PlUMJWa bullOMIMJM MSWatl Sttbfc fan bullraquo-staMr alaquoovs of N i - I raquo M o - 7 Cr bull Al and Ti with remcct to p i M prime precipicslioa m S0 and 704degC Alloys above the lines win form ttamma prime and those below wifl not (see Table 64 for the compositions o f the various alloys I
Tab 67 Stress-njptare data for several Urals of litaMM-almiNMM modified Hastetoy N at 704 C and 3SJO X 10 psi
Ileal Compoutiofi twt bull 1
Ti Al
Rupture life (hr)
Total strain
Age hardens at 704C
474-901 474-5 J J 427 428 429 430 431 432
18 217 24 247 24 25 25 235
raquollraquo 1148 IMS 016 035 034 074 069
006 005 0014 0064 0017 0073 0016 0057
1932 I96 0 820
2018 2006 2124
29383 36115
394 420 234 610 227 558
68 137
No No No No No No Yes Ves
Base Ni I Z Mo in Cr
Result ltgtf hardness measurement taken on ated unsirnsrd specimens
78
7S-1JTraquo 20
raquobull
14
an c
i lt
laquo0
bull433
bull 435 U^TA j raquo44l
438 _Llaquolaquo
420
- bull 4 2 5 -
bull 434
mdash~3poundt^~ 4lt8
25 30 42t -bullmdash 35 40 45
at (NbraquoTraquoi) 5 0
Fij 6 J5 Chante M kmimm ol 1 vanon beats of Nb-Ti-AI-amdiTied Haste N after 1000 kr at 650C (see TaMe 64 lor the coMposinons of the bullMiow alori)
TaMe 64 Coayison of hardness changes4 aad creep beharioi of Hasteloy N moOfttd with Nb Ti sad AI
high in titanium does not seem to show much aging Alloys containing 3 to 5 at (Nb bull Ti bull Airaquoage appreshyciably with creep rates of about I X IO3hr or less
The above results indicate that zlloys containing approximately 25 at or less (Nb bull Ti + All will be satisfactory from the aging standpoint Such an alloy would be represented by the composition on a weight percent basis of 05 Nb-I5 Ti-01 AI Alloys having concentrations of Nb + Ti + AI above the 25 at range will be more susceptible to aging
Future work will include evaluation of mkrostructure for a number of these specimens to confirm present conclusions evaluation of additional alloys to test the indicated boundaries for stable compositions and an extension of data analysis to determine whether a quanshytitative relationship can be derived that separates the relative effects of the individual elements Nh Ti and AI on the stability of alloys of this type
65 MECHANICAL OPERTIES OF TOANIUM-MODIFIED HASTELLOY N ALLOYS
IN THE UNIRRADIATED CONDITION
T K Roche J C Feltner B McNabb
Several tests were completed or are in progress to determine the mechanical properties of recently reshyceived heats of 2 Ti modified Hastdloy N in the unirshyradiated condition These alloys include two production heats (74-901 and 75-421) and six semiproduction heats (74-533 74-534 74-535 74-539 74-557 and 74-558)
behavior of several heat
Composition Hardness Kg Minimum creep rate
Cilhx) Heat wl 1 at Annealed 1000 hi
al 650C Change Minimum creep rate
Cilhx) Nb Ti AI C Nb fi + AI
Annealed 1000 hi al 650C Change
237 103 004 lt005 084 15 x 10bull 63 25 lt00I 013 166 il X 10 181 185 050 lt001 0045 186 31 x 10 bull 69448 195 092 005 0043 255 70 x 10 69-344 17 077 024 010 263 26 X 10deg 70-835 26 071 010 0053 282 60 X 10 425 048 19 008 0037 290 801 841 40 78 x 10 421 104 19 007 0O48 324 873 865 -0 8 13 X 10 424 134 18 01 0063 338 886 902 16 71 x 10 418 192 20 005 0058 391 891 904 13 22 x 10 420 190 18 015 0055 387 887 1015 128 1 X 10- 433 189 22 033 0024 475 84 1043 195 2 x 10 434 186 22 032 0061 470 933 1070 137 3 x I 0 -
Alloys aged for 1000 ht at 650degC and hardness measured in unstressed condition Creep tested at 650deg C and 470 x 10 psi f Base Ni 12 Mo 7Cr rflhratll77C
79
6 OANL-OTN 75-Wtf
5 5 k 433 1 raquo434 | 1 1 iHll
- (
I
gt420 M 1
1 tlltk^
- (
I i i
70 -835 lt i T ^ 1 | U 1 bull 69-648 6 - 4 4
I
1 425
2
1
I II 1 i i |
bull S3
M81 2
1
1 1 1 1 i
1 |
bull 237
I 1
10 i - raquo tor4 2 5 laquo r 3 2 s MINIMUM CREEP RATE 1nr)
10 io-
F 626 MiMam cteep rale of vwkms heals of Nb-Ti-AI-nodified Hastelloy N tested at 650degC aatf 47Jgt x 10 pa (s Table 64 for the aloy coiapositicm)
Four of the six semiproduction heats contain small additions of rare earths lanthanum cerium and miscii metal The compositions of these alloys were chosen to study the effectiveness of rare-earth additions for minishymizing the extent of shallow intergranular cracking Each of the six semiproduction alloys was the prodxct of a 120-lb double-melted (vacuum induction plus elec-troslag remeit) heat produced by an outside vendor The chemical analysis of the alloys was reported preshyviously5 The mechanical-property studies include the determination of room- and elevated-temperature tensile properties and creep-rupture properties in air at 650 704 an J 760degC These data serve as a reference for comparison with the properties of standard and other modified Hastelloy N alloys both in the unirradiated and irradiated conditions
The principal effort during this report period was directed toward completing the creep-rupture data on the above heats Tests are being run at three stress levels for each of the three test temperatures Most of the tests were completed with the major exception being heat 75-42 he 8000-lb production heat for which specimens are being prepared Specimens of the other
5 T K Roche 8 McNabb and I C Kcliner MW flj-gnm Stnimnu Progr Rrp Feb 2 1975 ORNL-5047 pp 61 and 65
heats were obtained from swaged rod and were annealed for I hi at 1177degC prior to test
Figures 627 through 629 are plots of rupture time as a function of stress at 650 704 and 760degC respecshytively for the 2 Ti modified Hastelloy N heats and are compared with plots for a previous heat ^471-114) of the same alloy and standard Hastelloy N Minimum creep rates measured from these tests a the three temshyperatures are shown in Fig 630 as a unction of stress As concluded previously the more recent heats of 29t Ti modified Hastelloy N are essentially equivalent in strength to the earlier heat and there is no significant effect resulting from the addition of rare earths to the 2 Ti -modified alloy As determined from past work and confirmed by the recent tests the modified alloy exhibits longer rupture lives than standard Hastelloy N at the three temperatures
Additionally the first of eight creep machines capable of tests in molten fluoride fuel salt was put into operashytion A specimen of heat 474-533 has been in test at 650UC and 300 X 10 3 psi for slightly over 1300 hr Data are not available as yet on this same heat in air but a comparison is made in Table 69 with an air test of an earlier heat (471-114) of the same nominal comshyposition
The data appear to be falling within a normal scatter band for alloys with the same nominal composition that
80
10 2 5 KT RUPTURE TIME (Dr)
Flaquo 6-27 Sueswuptare properties of several heats of 2 Ti-modified Hastcfloy N and standard HasteRoy N at 650 C I Ranges of rupture strain indicated in parentheses)
60
90
= 40
laquogt 30
20
10
0MH-DWC 79-laquoS7raquo0
[ mdashr-1 i j
- laquo gtlaquo 2 Ti-MODIFI bull0 bull AS El -LOT N (HEAT 4 r i - iu raquo i h t
B ( 39
h 4 -
r
II 6261 r ( 3 7
bullIs
I 2-476) -
laquobullraquo bull (
i
bull 174- 33
1
39
h 4 -
r
II 6261 r ( 3 7
bullIs
I 2-476) -
laquobullraquo bull (
368-47
1 6
A 474-535 laquo 474-539 o 474-557
-STANOARS HA STE
I-
LL OY N
o lt raquo74-laquo
1 L
KM
1 1 TES II
T TEMPER
III ITUR
STE
I- 70 4C
11 V 2 10 tOJ 10 RUPTURE TlaquoE (hr)
Fit 62 Strcavmpfare prupeniei of several heats of 2 Ti-modrTwd HacMfojr N aad staadaid HaateBoy N at 704r (Ranees of rupture strains indicated in parentheses)
81
Tvaoraquo 35
30
25
I- -
11 1 1 1 M IMP i | TT bull1 X I i h i j i i
bull -MODIFIED HASTEU0Y N CHEAT 471-14 -1 i IIIH |
i bull i i i
i gt lt
I i h i j i i bull -MODIFIED HASTEU0Y N CHEAT 471-14 -
1 i IIIH | j
j
j | i i
M 1 nH t t Y-
r 1 i n 1
t bull 1 I t I i |
i i i i i V bull i i bull i bull
raquo 474-533 gt 474-534 i 1 M h i t raquo 474-533 gt 474-534 I r bullv M I f f bull 474-535 raquo 474-539 I M i i i 11
o 474-901
1 Mi l l i i T
1
TEST TEMPERATURE
ill I i BOT
i IN to bull 0 2 2 5 SO5
RUPTURE TIME ffcr) bull0
F i j 6 2 9 Strcss-raptate properties of scleral heats of 2 Ti-modified Hasttstoy N and standard lUiMMoj N si 760C- (Ranee of rupture strains indicated in parentheses)
omn-oac n-tsret TV
f 2 5 raquo - MINIMUM CREEP RATE (hr)
Fig 630 Creep properties of scmsl heats of 2 ft-modified HasteHoy N at 650 704 and 760 C Solid lines arc for heat 71-114 and the dashed lines indicate bands which contain the data for the other modified alloys
S2
T M H -Ac mdash l i i r a s w a raquo laquo 1 l
larl 474-533 471-114 iflaufijc farii ltagt
500 13 24 1000 44 1300 35 55
Tlaquowraquo ion ai 650 C n d 300 x 10 pa
are tested under similar conditions and there is no indication that ronoaon by the molten fluoride fuel salt represents a sgmficani factor
jraquo rOSTIRRADUTIONCREEf MtOftRTIES OF MODIFIED HASTELLOY N
HE McCoy TJC Roche
puurade of the ORR Each experiment contains 102 miniature creep specimens in an instrumented facility in whkh temperatures can be measured and controlled by supplying heat from auxiiary heaters Only 12 in-ceU creep uwrtnim are available for postirradianoa creep testing hence the testing proceeds rather slowly The most recent tests have concentrated on lt I ) the propshyerties of six 125-lb senuproduction nests that contain 2 Ti and low concentrations of rare earths and (2gt the properties of several alloys containing both niobium and titanium
The results of tests completed to date on the six heats that contain titanium and rare-earth additions and the (OjOfXKb commercial heat that contains titanium are summarized in Table 610 Previous tests at temperashytures of 6S0 and 704degf showed that the creep propshyerties of these heats are about equivalent The rupture nfe at 650degC and 40JO X I 0 3 psi varied from 1200 to iSCC hr and the rupture life at 704degC and 350 X 10 psi varied from 170 to 200 hr Final conclusions con-
Postirodtion creep tests are in progress on specishymens from five experiments that were irradiated in the
6 T K gnmSemm
Roche i ( l-dlner and B McXabb MSK Pro-mm flop Rep Feb 2 1175 ORNL-5047 p 7
a t 6 S r C a r laquo s a o M n i atUttMecatca
ABojr Ten mantel
Irradiation tcmpcniafle Si ecu
(10 pa) creep rate
(hr)
Rapawe life (hrgt
Total fracture straia Cufaycailioa (gt
474533 R-I9I2 R-190
R-I929
650 650 7ltK 760
400 470 400 350
0025 0050
0035
2311 I I I 5 2
2022
72 217 Ti 04 At 7 6 4 7 J
474-534 R-1913 R-1909
R-1930
650 650 704 760
400 470 400 350
0021 007
0008
5722 660 5raquo 7 3
16 2 209 Ti 0 J 3 Al 001 3 La 69 35 28
474-535 R-I9IS R-I9I I R-1922 R-1926
650 650 704 771
400 470 400 350
0016 0099 0023 0019
7 6 M 930
4677 6454
1V6 2 1 3 Ti 055 Al 004 rare car TS
123 139
474-539 R-I9I4 R-I9I0 R-I92I R-1925
650 laquoS0 713 774
40 JO 470 400 350
0020 011 0C3I 0000
601 739
4295 12200
108 193 Ti 020 Al 003 Ce 97
165 114
474-557 R-1920 R-1923 R-1927
671 713 771
470 400 350
0045 0044 0019
2174 162 434S
1 0 214 Ti 002 Al 95 S3
474-55 R-I9I6 R-1924 R-192
650 716 795
470 400 350
0X192 0021 0012
1793 475
79 205 Ti 0-02 Al 002 U 6 II
474-901 R-1936 R-1937 R-1907
650 70laquo 732
470 470 470
0069 015 014
1716 332 525
1 3 10Ti00Al 52 1A
AD specimens lancaM I hr agt 1177C prior (o irradiation for M 100 hr to a thermal thence of vlt3 x 1 0 neutronscm Alloy nominal bast composition of Ni 12 Mo 7 Cr -005 C
S3
cerning the postinadiation properties (Tabk 610) are not possible because the tot matrix ha not been comshypleted Specimens irradiated at 650degC and tested at 650degC hare rupture lives that are about half those of the unirradiated specimens but there are no differences in the properties of the various heats that are considered significant in view of the limited data The properties of afl heats are considered good after irradiation at 650C After irradiation at 704degC and testing at 650degC and 400 X 10 pa the rupture lives of heats 474-533 and 474-534 appear to be lower than those for the other heats by a factor of 3 In afl cases the rupture life and the fracture strain were lower after irradiation at 704degC than at 650degC After irradiation at V760C and testing at 350 X I 0 3 psi at 650C the rupture fafe varied from 43 to 1220 hr and the fracture strain from II to 114
respectively Thus differences in creep behavior of th-se aftoys likely become progressively more important as the irradiation temperature is increased
The fracture strains of the various heats appear to show significant trends with increasing irradiation temshyperature Heats 474-533 and 474-557 have good fracshyture strains (6 to 104) which do not decrease apprecishyably with increasing irradiation temperature The fracshyture strains of heats 474-535 and 474-539 are i t the range of 10 to 16 and do not change appreciably with irradiation temperature Alloys 474-534 and 474-558 show decreasing fracture strains with increasing irradiashytion temperature The behavior of alloy 474401 appears to be unique in that it shows a marked drop in fracture strain as the irradiation temperature is inshycreased from 650 to 704C However this effect may
Ta t 611 bullMtffiall rNamwsaKsrc
Alloy Test HftlhCT
Sims HO psi)
creep rale
Rapt me ate lthrgt
Total fraclarc sin in
rfhraquogt
Rapt me ate lthrgt ltgt
428 R-1948 470 0043 2221 119 474-533 R-1908 470 0050 I I I S 78
R- I9I2 400 0025 2311 72 430 R-1947 470 lt00049 9720 4 8 r
432 R-1946 470 lt00005l 9720 0SC
431 It-1945 470 bullCO0024 972f 424 R- I9 I9 350 Mraquo 3160
400 000024 1406 470 000033 4526 550 00066 9494 78
424 R-1944 630 00096 3554 104 420 R-I9I8 350 bullM) 5322
400 -v-0 1405 470 000021 4509 550 000037 6959 630 000080 3343 700 00062 2776 4 3
420 R-1943 630 lt000l7 10680 18 418 R 1917 350 000002 6514
400 000007 1406 470 000014 4523 550 00040 7948 54
41ft R-1942 630 00022 5592 72 434 630 lt0085 129 II 433 R-1949 630 lt0 00 l l 6600 075
AN specimens annealed I hr al I I77degr prior to irradiation Irradiation carried out al 650C for approximately 1100 hr to a thermal flaencc of Vraquo x 1 0 neutronscm See Table 64 for detailed chemical analyses Test still in progress Stress increased on the same specimen in the increments shown
S4
tt12 laquo T SIMMS CM
AcebaMk maibS0CbjMlaquotoi rtniliij1i4
CoMBoanmi iwt rt Co H o
lOOObraMeal
ctccp cveep behavior
bull S O T f o r V I I W b f 4
CoMBoanmi iwt rt Co mdashjn bullnn a m t H o
lOOObraMeal
ctccp cveep behavior
bull S O T f o r V I I W b f 4
Nb T i Al Nb bull Ti bull Al
428 No No No 247 Olfc 357 474-533 No No No 217 laquo4t 3 raquo 2 430 Yes Yes Yes 2J 0 J 4 492 432 Yes Yes Yes 235 0Alaquoraquo 4 A 3 431 Yes Yes Yes 25 074 4 9 424 No Yes Yes I J 4 I S 010 33 420 Yes Yes Yes 10 I S 015 3S7 4 I t No Yes Yes l laquo 20 005 3 1 434 Yes Yes Yes iaraquo 22 032 470 433 Yes Yes Yes l laquo 22 033 475
Sec Tabfc 1 4 for c l e t M e U t f e M U analyses
F I O M Table 4 rFroaraquo Table t A based ltM ctmatemiomt of data i ON novate Me aMl total u n a rfFrow Table 611
be related to the strain rate a summary these sparse data sanest that the fracture strains of alloys cow-taming only titanium and those containing titanium plus cerium remain at adequate levels as the irradiation temperature n increased while the fracture strains of the two alloys (474-534 and 474-558) that contain lanshythanum do not Additional specimens were irradiated and tested to check tins important poatt
Section 64 of this report deals in detail with the metaOurgical stability of alloys containing Nb Ti and Al in the unirradiated condition Some of these alloys have been irradiated and limited test results are availshyable (Table 6) The alloys were annealed for I hr at 11770 prior to irradiation for about 1100 hr at 650C The anneal at 1177degC should have dissolved most of the alloying dements and the subsequent period at 650degC may have resulted in the formation of gamma prime Precipitation of this embrittling phase abo strengthens an aBoy hence the postirradution creep tests should show whether significant quantities of gamma prime were formed As dacussed in Sect 6 4 precipitation of bullhis phase may be strain induced and a detailed analysis of the creep data wSI be required to determine whether the gamma prime formed m the specimens during irradishyation or whether it fonrvf as the spedmens were stressed initially
The data from Table 611 and information from Sect 64 are summarized in Table 612 which shows that the
conclusions are reached with regard to aging of creep specimen in the unirradiated and irradiated con-drtions However hardness measurements on unstressed umrradaied specimens fail to be a good indication of agt in aRoys containing nioHum Alloys having a com-tlaquoKd titanium and aluminum content as high as 357 at had excearnt postirradution properties ABuys with higher uimbimd concentrations are quite strong Kut no conclusion can be made about their fracture stains All of the alloys containing Nb Ti and Al are quite strong and can lake considerable strain before fracturing ABoy 434 has a low fracture strain waste no conclusion can be drawn relative to ahoy 433
The alloys containing Nb Tiand Al which have been evaluated thus far are likely too highly alloyed even though some of the fracture strains jre acceptable Less highly alloyed materials are being irradiated
67 MlCKOSTRUCTURAL ANALYSIS OF T i T A N M M I O W I E D HASTELLOY N
D N Braski J M LeMnaUr G A Potter
The first part of this section presents the results of microstruclural studies of two titanium-modified Hastefloy N aloys 472-503 (designated 503) and 471 -114 (designated as 114) Previous analyses of these tame two alloys dealt with their nricrostructwss after
bulls
afmf aad after postsrraanrtion creep tests In the pressai m f j i l f the nacroairaciaret ot hutfcaftoys were analyzed M an attempt 10 explain some w u l pouarsdanoa creep teattts M sptoaaas that were pven a ltjfgtrtj higher soratiua aaaeahnf treatment Move trratmttian I V mdym showed that many at the wlaquo ipninsrai owe t f i e mhumimracnni and that tkc poor creep properties ttiaMmsonsr cases tie related lo the iahomimnKitsti D M ftnamg prompted a sindy aanei at iiiiidwiag asm hinaimiatimi llamllin N aloys The problem if betw approached by rcdactae it carbon coateat of the anoy aad by gnaw carefal attention ID the tahjicatani pmmHcn The resales ot taaml narranrnti to tnWicalt hiaanpariita alloys arc pKsvnacd m BM secoad part o( thjis section
471 M f u m i r i a i J M r laquo f JkaaysSISamllH
rVanmnaaaaa O H I I o n The retails of creep ten o specimen of ahoys 503 aad 114 which had keen PKVSUmdash)y irradiated in the ORR al 7a0C Me given in I hgt 6 J I The creep tots wete contacted at 6501 n a turn and of 350 X I 0 3 pa This partwalar scots laquoraquof spnameas was designed lo show mc effect of tobmoa anatjbni remperatarc on the postkravniion aeep rop-r-re We of the naieriah The solation anneal was a I-hi heal ireainieM and was given lo all sprcimens before ikes were irradiated 4 men in Fig 6 J I ibe 503 speci-men given the standard I br at 117 ( solation anneal demonstrated food creep iiipiwic We wbifc the 114 tprvmen given the amc ircaimenl had a comparably short lifetime However with an mcrease of only ^30degC in aim latins temperature ahoy 503 had a freatty reduced lifetime wMe ahoy 114 thawed marked improvement It wn corasdered ankkety that tkese rendu coaM he canted by changes in solution anncaing tcmpcrainre alone and other posabh cxpla-aatioas were soajbl It b important to note that despite the apparent mtfaMiiy in creep behavior the properties of the 2 Ti modified alloys arc gencraiy food The problem is that lo determine why tome specimens have poor properties A bullohtlhm to this problem was sonjht by carrTafly anatyimf the microttrnctnres of the two alloy 503 and 114 tpecrmens described above
7 D N bullgt I M UMmfccr jml f i A Puller JfSff AOBVM Semtmmm ffngr Hep Am J I 174 OHm-5011 pp 2 M
n I) S Hrai I M Inraoker j J ti A fnwr 10ft rtomm Semtmmu hop Htp Frh 197 ORNI -5047 Pf i vn
am-a t-laquotlt H 0 O ^
snvss ifwfi bull raquooooraquot
llaquo00 i bull ~ i
bullooraquo 7 1
SOI I
1 z- 2 aosf tr
w r T~iHr-wV---
eoo^mdash mdash mdash - 7 - l V mdash ^
laquoooo tlaquooo laquotoo laquoJOC tOkwtio mntauvs rtanjntTtM ltKgt
Hattys SWanf IM at wfTC ahw Irmthmm toOU wr laanm
TtasmnJtvJmi eltclnm nncrattwny Samples were preshypared for iransnaanoa ekciron nacroscopv iT lMi bgt elevtropohaaaf small transverse sections a( the tested creep specimens in perchloric acid sohrtions Frfures tgt32 and 6J3 show electron naaofrapbs repteseniattvc laquogtf 503 and 114 specimens respectively Hfare tgt32 shows an area near a frain boandargt in the 503 specishymen annealed at I I 7 7 C The nacroHnictaie was obshyserved to contain NT-type jwkaiii both in the ftsin bnandiry aad m the form of tmaH ptattieis DMoca-lions were nearly always foond to be aawoMcd raquotih ike MC plasestis The 50specimen anaeaWd at iagtraquoC had ssaabw featarn laquoFsg 6-321 In both speenneas ibe MC pbielets were coaccntrated near the grain boundshyaries This tajfrsts that the element or elements (probshyably titanhan) awimf ap the MC-type carbide in both specimens wete not anifonaty dittrrbwted ihroafhoat the ntntrix Rfare 6JJ shows ehxtron araquoao|raphs of ike 114 specimens aaaeated at II77C(Fig6J3tand I204f (Fhgt 6J3raquo These specinwas also contained tine hJCMype cjrbidei bat aalwd of formmf pbtekts they precipitated oat on stscUnf faalu The suckmf fault precipitates initiate from iaiocstioat aanriaUd with preexitlmi or primary MC carbides and frow atom ( l l l l pbmrs The primary bX carbides (the dark
9 J si raquotVudt j4 raquo ) IWHUM PariHl Praquogt^i-raquolaquo
FfctJL iirrcraquogt
IMi to to ON m C alaquo r c w i laf I fct laf ItonlSMT
FfcUX 11 rrr laquoraquoMMMI~
bullraquo laquobull IH aft i 4rflt ifctMijarr
bull7
bullJS maunutj I t 93 n r r r IFBJ 6jlaquoaraquo a hai laquobull
face ocal oadu laquo laquowieau of
I M laquo F v J 4 laquo ^
f i W t laquomajm awir loaae Iraquoraquo bull ulaquoaagt aavm tar rmttte mctmm of tar Maaak TW laquoaraquo-hlaquoir i i i i f m mt omtfutd raquoH w w n n MC-fraquoar pat-iarraquo atad ar m bar pml r i nraquo the | bullveil) at fafencaiMa)- Suit aifcaiettfaiamare i loth atatuicw M Fa 6J6 bgt the iafJMf t laquo mdashlaquopmm ukra gt4 oW 503 aajdaara 1W 503 laquofrltMMraquo J M K J M j i I5M C hai oaka iem tracks Ifiy 634raquo| feat laquoa a lacat arja aaaarealh Me to
ka4 a sfcvrt crer raatare life aha M a ^bullXM2laquo4hKk m l Mi fit my (filaquo J5 IL K M -
bullera m mm Sm mtomm (Fftj J4raquo|i h mm akv I thai aartee aacks bull jraiar fiw layer TW 114
I2MdegClaquoFlaquoJ$raquo)lt
the tenet 509 aaaatn (Fig 3Saraquo Hat layer tana) a e 53 mm 114 air-aafi
aa ie i t jn at II77C ai anjon
baen of i l aaa ltA0J raquo ) a w u t e m I at aacoad 617 after OlaquoCP tern at I W f C raquooraquo i r at bullraquo M a a OI I I I i n 500 pmm oBjaea- T V bet of cartwtci ai tar tarface lever any teae at tarn
in I U a laquoN1 i fcc ~ IW f f v i olt bull m bullbullbull ngt bull mp ttaatmdash ftuauwt l laquo a i i rlaquoWKftll~l raquofJaar 1731
617 M
+rnm
OTraquomm
ttm mOtOimTttrc am IMtMTC
growth m the 503 specimen (Fig 6 35| during the soMMwa mmtd h is Midear as to
certain tptcimrai haw the carbide-free layers 1 specimens were svoposedry fabricated in the
same way The malts of the mrtafcajraphtc and TBI lt
lion cannot be nsed to fnty explain the i which led to the early creep fnlnrc of two of the specishymens studied However we banc shown that a awnber of aticrostractaral inhoniofmirties exist in the 25t Ti asotified rLarloy N aftoys induding carbide-foe sur-face layer tnrft-grsia lint snrface hyers nmeratwd carbide strinnprs and nononifonn diHribniions of Mf-type carbide nor grain boundaries Some of these
ties appeared to affect the resnhs of tots and may also inflnence other hnpor-
snch as those renting to tclarium attack Consequently a stndy was initialed to prodace rtsstd-loy N aftoys with more homogenous nacrostradares
bull J J llinnnmiim UnmfJy H Aiayraquo
The problem of prodacing Hastdoy N alloys with hiuaugtmuui nacrostructures is being approached in two ways The first is to reduce the carbon content in the atoy to ensure that aR of the MC-type carbides are diaailvud daring the solution annealing treatment If all
the carbides could be held in solution daring fabricashytion the formation of carbide a ringers might be eKna-aated The second approach b a detailed evaluation of tbt fabrication process This latter effort is prwmily
at identifying the steps at which the different ae introduced and finding suitable
akemate processing methods to remove the anno-anajftiti A definite concern throughout the entire study is that any successful fabrication changes also be
immmiil practices The first series of experiments was
to cmnJnate carbide stringers by reducing the carbon content of the ahoy Thermodynamic takula-tions aung data from previous experiments indicated that aN of the carbides should dnsorve at I I77degC in aloys with carbon contents of less than OA45 wt 7 Therefore two aloys 451 and 453 both wtth a nomishynal lauteaoy N convocation (13 wt Mo 7 gtt Ct bal Ni) and 144 wl Ti were cast into l-m-omm marts having carbon contents of 0017 and 0035 wt 7 respectively The fabrication schedule called for the cast ingots to be hot swaged at I I77degC from a I-in to a 0430-in diameter and then to be annealed at I I77degC for I hr The rods were farther reduced o a 0 J37-in diameter by cold swaging annealed at I I77degC for I hr and cold swaged to raquo final diameter of 0250 in One-inch-long samples were then cut from each alloy rod
bull 9
encapsulated in quart urJer an argon atmosphere and aged at 7G0degC for 16-5 hr to precipitate the carbides After aging the carbides in alloy 453 (0035 C| were extracted clectrochermcally in a methanol 107 HC1 solution Consecutive extractions produced the profile shown in Fig 6 J 7 of wt 7 carbide precrpiuie through the thickness of the sample The profile for alloy 453 is considerably more uniform than those obserad for alloys 503 and 114 specimens aged at 750degC for 1000 hr The difference may not be entirely due to a reducshytion in carbon content because the 503 and 114specishymens were swaged from bars cut from i-in-thick plate not from drop-cast ingots (Carbides are fairly unishyformly distributed in the grain boundaries of the 2-lb laboratory ingots while they appear as stringers in the A-in plate) Meiallographic examination of the aged 451 and 453 samples (Fig 6 J 8 ) showed that the reducshy
tion in carbon content did not ehrninafe the carbide stringers However the stringers were liner and more evenly distributed than those observed previously (Fig 6J4o) Carbide-free surface layers were observed in both specimens a typical surface layer in a heavily etched 453 sample is shown in Fig 6 J 9 The depth of the carbide-free surface layer was V0U03 m
Fatifcpnwn One of the moat critical steps in fabrishycating tbtf^iioy N aRoys with respect to its effect on microstruciurr laquo the solution anneal Electrochemical extractions on an as-swaged alloy 453 (00353 Cgtsamshyple showed that a moderate number of carbide panicles (M) 2T) was present Hi the microstructure after procshyessing It a suspected that the sample was not adeshyquately annealed at 1177degC prior to the final cold swagshying operation That is the annealing lime was too short or the annealing temperature was actually less than
90
0080 O0TS FMQHOWTEtOF
X amy Mkif S03 JI 1177 f M lt jpee gti laquocopylt for
I ITTC Therefore the respuMe of tiUmum-mudifWd thneloy to sohnion aaandias at I I77degt ws stmfced as a fmctioa of time at temperature
Samples of aloy 451 |OJOI7 Craquo W anon at I IT7degC for 15 mm lo hr The cleaned etectrucheaacaRy for 6 hr to remove any nr-faoe effects ami the carbides were electrochemical extracted separated ami weighed The resatts of this experanent aw plotted m Rg 640 (My extremely
bullis of prcopitaies were present a samples for 2 hi or more At times less than 2 hr there
scalier m the data hat m geaerai chfHIv preopifc te was extracted These remits indicate
that JO to 60 mm are weeded m addition to the stanshydard 14 sohtiox anneal at 11 T T r to dtooKv the carshybides completely Muumaptu of tectioas from each of the samples r f aloy 451 from the first jaarmaj series are mown irgt Fig 641 Little gram growth was omened between the 154am and 14v anneals while mgbt grain growth was etideai after 2 hr at II77degC As expected rather extensive growth occurred at the longer j times of 4 and 8 hr
FfcnJB Wcwsmnmwof limn wimfml llsmliy N amyi451 jM7Cgt anl 4raquo IftWW O after coal maawwanl aanf at TMTCfbr I US fcr (laquogt Alloy 451 laquoAgt AHny 45 J
91
foert seed-
Abhoaeb most of ike effort m ties stedy hat beea pit wii be exammed mdashtuiognfkicjh before deeded towvd etmeeetioa of canede miegrn a the aflaquoer a soaatioa aaeri at 1177C I b j bull a bullloys enprrimdashrii aieafao mdashdet way to i i i f i i a n the iimiag eomt a t e mdash taebidr few b y m cjHeoftie carbide-free layersm oar experiment Bee- alnae ibr mdenrd irrliw nf
a w that n any effects of bet or cob) Y-133201 mmraquobemremoeedby
there is ike coaaderata eery bull fact be the bey to uioootaH a ahoy A aoajher of rchmvesy eeeor cheaats bull the way ibe eeecviel is leeeeed amy mwe oaaaaptK effects oa
4SI awi 453 aie ui l i l l aai wal be tnMcated to CiVideraquofiw]|Bmemmmmmmmmmmmmmml 025ampmemai rod with special attewtioa peel to the
CSl nOwal t h e W O f k HBOC l lHOWHKNVt the B I O O 0 B H K SO
J SALT COMtOOON STOKES
J R J R Difdkno E J Lawrence
by of
FbgtraquoJ9 i t u n a
453
The conoaoa of bow) asefcei-mniten ihtonac salts has ben the research for aemy years Resell seen as FeFj NiF and HF in the sah react with con-sliteeats of the alloys bet corrosion from these soartes a basiled by the seppiy of reactaets The strongest oxidant of the normal coaetiteeats of foH salt is UF 4 and of the major coastrteeets of most iron- am nkfcei-base alloys cbrommm forms the most stable fleoride Coaeeoeeetly the major corroajon reaction between
02 OftftJL-OWG 7 5 - 1 2 2 4 )
5
imdashimdashimdashr o 1st ANNEALING RUN laquobull 2nd ANNEALING RUN o 3rd ANNEALING RUN bull 4th ANNEALING RUN
2 3 4 5 TIME AT 1177 C (hr)
FfeSvMl AmcmMoliBAim$9tncmihomraquonor4Slmraquotmgtctomlt4Vmmmitioraquo
8
bullfii7rc
92
to) CM ltlaquogt
FltMI MkioaMjai of mdash bull I br kit 2 br laquoraquobullraquo 4 br jfld if) nr
i laquorf raquo r 451 aftw M M M Mlirrcfcw tol IS i ltraquogtMl ltrgt
nickel- or iron-base alloys and molten-salt reactor fuel salt has been found to be
2UF 4(dgtCrfc)^2UF(draquoCrFj(dgt
Because the equilibrium constant for this reaction has a small temperature dependence temperature gradient mass transfer can occur and results in continuous reshymoval of chromium from the hotter sections of a system and a continuous deposition of chromium in the cooler sections
The experiments described in this section are being conducted to determine the corrosion rate of various
sall-afloy systems under controBed test conditions The variables include compoatiou of the alloy oxidation potential of the salt temperature and exposure time Afl loops incorporate electrochemical probes to measure the concent ration of uranium and transilion-metal flushyorides The systems used to conduct these experiments include one forced circulation loop operated by personshynel in the Reactor Division and three thermal convecshytion loops Five additional thermal convection loops have been constructed and are being prepared foi effrj-tion The status of these eight thermal convection loops is summarized in Table 613
93
i l l l f lS
IA
raquo
raquo
tit
MRSkr
l l t e M JS
rN
it
h i
M l
laquo J I Fael M l
Two thermal convection loop NCL 2 IA and NCL 23 have been operating with M S W fuel salt iLiF-BeFj -T lr f^- lF M M 1 7 - O J mote ^raquo lo obtain baseline common data NCL 21A is a HasieOoy N loop with specimen of the same material At with a l thet-mal convection loops dghi specimens are inserted in the hot and the coid legs The 16 spedmens are reshymoved periodicaly for visual examination and weighing The results of the weight change measurements are shown in Fig 642 The corrosion rate of the hottest specimen in this loop is somewhat higher than has been observed in other rfasteUoy N systems (see Sect 682 discussion of FCL-2bgt The higher corrosion rale of loop 21A relaies to the relatively high oxidation potenshytial o( the salt in this loop ( U M about 10 I Horn-evei assuming uniform removal of material the corshyrosion rate of the hottest specimen was 024 milyear which is within acceptable limiis This loop will conshytinue to be used lo obtain corrosion data for Hastelloy N in kali with a relatively high oxidation potential
Loop NCL 23 is constructed of fnconet 601 and has specimens of the same material A loop was built of tnconel 601 because of this afieys resistance to grain boundary penetration by lefuriwn Since the alloy conshytains ZV Cr there was concern about its ability to resist attack by molten fluoride salt The corrosion rate of Inconel 601 in fuel salt was determined from weight measurements of the 16 spedmens of loop 23 and the results are shown m Fig 6 4 3 All specimens lost weight and the lost shown by the hottest spedmen w very large The material lost by the hottest spedmens did not result in uniform removal of the surface but resulted in the formation of the porous surface strucshyture shown in Fig 644 As shown in Fig 645 electron microprobe examination of this spedmen showed high thorium concentration in the pores The only known source of thorium was the salt which contained T h F 4 so it is very likely that the salt penetrated the pores Continuous line scans with the microprobe indicated a depletion of chromium near the surface Figure 646 shows the results of analysis for Ni Cr jnd Th This figure clearly shows the chromium concentration gra-
94
OMK-WH TO-IZZ4 1 1 1
0 laquo000 2000 JJ00 4O00 5000 SPECIMEN EXPOSURE TINE ltgt
Flaquo 642 Welaquoht campMfts of HasteBoy N p-ciaraquoeas fro loop NCL-2IA exposed raquo MSMt fad o k at the indicated tenMcnaMe
0OM-0VC T raquo - t laquo laquo 5
SPECIMEN EXPOSURE TIME (Hrl
F 643 Weht changes of Inconei 601 specimens from loop NCL-23 exposed to MSBR fad salt at the indicated tem-peratare
dient and provides further evidence of the presence of thorium in the pores Deposits such as those shown in Fig 647 formed on the specimens in the cold leg and the deposits were identified by microprobe analysis as chromium This compatibility test of Inconei 601 in MSBR fuel salt shows a relatively high corrosion rate and it is doubtful that this alloy would be suitable for use in an MSBR under the conditions of this test
The lower limit for the U ^ U ^ ratio in an MSBR will likely be determined by the conditions under which the reaction
4 U F + 2 C i r 3 U F 4 U C 2
proceeds to the right Because the salt in loop NCL 23 is strongly reducing with a U ^ U ratio of less than 6 it was decided to try to reproduce the results of Toth and
Gilpatrick1 wiuch predicted that at temperatures below 550degC and VV ratios below 6 the U t would be stable However graphite specimens exposed to the salt for 500 hr did not show any evidence of U C 2 The specimens used were made of pyrolytic graphshyite and it is likely that the high density of the material limited contact of the salt and graphite The experiment is being repeated with a less dense graphite
682 Fad Salt Forced Gmriatioa Loop
Hastelloy N forced circulation loop FCL-2b has been operated during this reporting period to gather baseline corrosion data under conditions where the i r U ratio was relatively low (see Sect 23) Eighteen itastel-loy N specimens were exposed to MSBR fuel salt with a U 7 U V ratio of aUut 100 The specimens were reshymoved at predetermined intervals for visual examination and weighing and the weight changes are shown in Fig 648 Six specimens were held at each of three temperashytures 704 635 and 566 eC Of the six specimens at each temperature three were exposed to salt having a velocity of 049 msec and three to salt having a veshylocity of 024 msec No -ffect of salt velocity on the corrosion rate was found so each data point represents the average weight loss of the six specimens The weight loss of the specimens at the highest temperature correshysponds to a uniform corrosion rate of 011 milyear Uniform corrosion at this rate is acceptable and well within the limits which can be tolerated in an MSBR
Following termination of the ^3200-hr corrosion experiment FCL-2b was to be used to make heat transshyfer measurements This operation has been delayed because a salt leak developed and a section of the W-in-diam Hastelloy N tubing had to be replaced (see Sect 23) Examination of the tubing in the vicinity of the leak is under way
Further corrosion measurements will be made in this loop with the U7U ratio at about 10 Additions of N i F 2 traquo the salt will be made to raise the U ^ U 3 ratio to the desired level
683 Coolant Salt Thermal Convection Loops
Thermal convection loop NCL 31 is constructed of type 316 stainless steel and contains LiF-BeF2 (66-34 mole ) coolant salt The 16 removable corrosion specishymens are also nude of type 316 stainless steel The maximum temperature of the loop is 639degC and the minimum temperature is 482degC The initial objective of
I I L M Toth and L O Gilpatrick The Equilibrium of Dilute UP Solutions Contained in (imphite ORNL-TM-4056 (December 1972)
95
_o o
tvri O
o O
-o d
FtJ 644 Microfracture of Incoad 601 exposed lo MSBR fad sah al 704 C for 720 hr As polished
Y-1312W
BackscoMered Electrons ThMc X-Roys
Ffc 645 Electron beam scanning image of Incond 601 exposed lo MSBR luH tall for 720 br al 7 0 4 C
HImdash3000 COUNTS FUU SCALE Ctmdash3000 COUNTS FUU SCALE THmdash000 COUNTS FUU SCALE
~~1
Y - 1 3 1 2 1 9
I L i JLJJJ - mi
Ffe 646 Mfcfopnbe ctmtimomi K M K M M M corroded ana in IMCOMI 601 exposed io MSMt M salt for 720 hr at 704deg C
97
Fij 647 Microstnctare of lacoael 601 exposed to MSraquoR fad alt at S66degC for 720 kr As pofohed
cobalt-base alloys is being evaluated in the unstressed condition in the TV A Bull Run Steam Rant Two heats of standard Hastelloy N tubing (N1S09S and N1SI01) are being evaluated in the stressed condition from 280 X 10 to 770 X IO Jpsi
The method whereby the specimens are stressed is shown in Fig 649 The wall thickness of the gage secshytion of the specimens was varied from 0D10 in (77X) X 10 psi) to 0030 in (280 X 10 1 psi) to produce the desired stress range The raquo-in-OD capillary tube conshynects the annulus between the two tubes to the conshydenser When the inner tube ruptures steam passes through the capillary and a rise in temperature of a thermocouple attached to the capillary indicates rupshyture Time to rupture can be taken directly from the multipoint recorder and plotted vs sfess for design purshyposes Data of this type for periods as long as 11000 hr were reported previously17
A photograph of the specimen holder (Fig -gt0) shows the ten instrumented stressed specimens the four uninstrumented stressed specimens in the filter basket and the unstressed sheet specimens bolted to the speci-
12 B McNabb and H E McCoy MSR Program Semiarmu Progr Rep Feb 28 1975 ORNI 5047 pp 94-101
OJKM-0W4 TS-lt22laquolaquo
O 500 IO00 ISOO 2000 2500 3000 3500 SPCCIMEN EXPOSURE TIME (hr)
Ffc 648 wetgtt changes of HMCHOY N from loop FCL-2b exposed to MSBR fact salt at die Minted temperatare
this loop is to provide baseline corrosion data on a comshymercial iron-base alloy The loop has been in operation for 248 hr
69 CORROSION OF HASTELLOY N AND OTHER ALLOYS IN STEAM
B McNabb HE McCoy
The corrosion resistance of several heats of standard and modified Hastelloy N and other iron- nickel- and
98
OB -OK M - 3
STEM SUPPLY 99ooplaquomgtr
t laquo - IT raquolaquobulllaquo
C t f U M V f TUBE
TUBE BURST SPECIMEN (TYP 10) WATER OUT
RETURN TO CONDENSATE STORAGE
f 649 ScfccaMtk of dostfe-watcd tobe-barst eciam
men holder The filter basket bolts to the small flanges on each side of the sheet specimens (shown exposed) so that the specimens are covered and the flow of steam is uirected over the specimens rather than around them The steam enters the specimen chamber near the middle of the stressed specimens in front of the unstressed specimen holder and is directed lengthwise over the two stacks of 2-in-long X H-in-wide X 0035-in-thick sheet specimens The steam passing over the specimens flows through the Neva-Clog filter to prevent scale from entershying the flow restricter orifice or the remainder of the steam system The steam is condensed and relumed to the condensate storage vessel No specimen has lost any scale so far but some of the Croloy-type alloys are beginning to develop blisters a prelude to scaling The oxide on all HasteUoy N specimens is thin and adshyherent with no evidence of scaling Some of the unshystressed Hasteiloy N specimens have been exposed to steam for 19000 hr at 538degC and 3500 psig Several alloys were included in this study andas reported preshyviously 3 they displayed a wide range of oxidation rates Several obeyed the parabolic rate law Aw = Kt0gt where Aw is the weight change in mgcm 2 r is the time in hours and AT is a constant Figure 6SI is a
log-log plot of weigh change in mgcm as a function of time in hours Note the sudden increase hi the rate of weight change with each alloy gaining approximately 05 mgcm z over the last 4000 hr This probably indishycates deposition of some substance on the specimens at a rate that was equal for all specimens We noted preshyviously that fine particles of iron oxide that was enshytrained in the steam had deposited on the specimens but this deposition occurred at a much lower and conshystant rale
The increased rale of weight gain for bulllaquo specimens was discussed with Bull Run engineers The Butt Run facility has had several instances of condenser tube leaks in the last year of operation whereas in previous years few if any condenser leaks occurred The cooling water in the condensers is at higher pressure than the condensshying steam to prevent back pressure on the turbines and when a leak occurs untreated cooling water is introshyduced into the steam system hot wed Continuous monitoring of silicon in the four hot wells (condensed
13 H K McCoy and B McNabb Common of Seven fron-md SirkelBttr AUoyj in SMptnrihctl Steam tt IWmfF ORNL-TM-4552(AupB( 19741
99
yen ttSO fhnnnif of MM M H mwooaw dumber attar I9JBM hr of ixpamdashJI Fntaro to note ire the ftrcacd D M mcmlnMnmicd iptcimem m ihr fitter Iforeiivimdl the two grown laquo f umtreued ipecanens and the tea nwuaacMcd tfrcued iptnanm The Miem-rf ltrcanem haw an oniadc domclcr at I in and a length of 3 in
steam wdfc) indicates a condenser leak when the silicon lewd increases and the leaking condenser can be isoshylated and repaired The condensed steam (and any coolshying water mtrodticed by condenser leakage) poses through demineahzrrs and is ntonitored again with silishycon and other irapuifies being held below acceptable broils before the condensate is returned to the steam system Even though care is taken to prevent excessive amounts of imonritres in the steam system the farihiy is evidently opt rating with a different level of impurities than had been experienced before condenser problems developed Some evidence of indium shkate as a Mack-Mi gray deponihas been observed on some safety-valve seats and this is poanoty the material that has deposited on the specimens The oxide on most of the specimens is Mack or gray and no changes in i u appearance were noticed during routine examination and weighing of the
specimens When the specimen holder is removed for the next scheduled examination an effort w i l be made to determine the composition and nature of the deposit
by Bofl Run engineers in the near future to ehrninate the problem of condenser leaks
Some of the aloys represented in Fig 651 lost weight inriiany before gaming at an accefcaraied rate during the last 4000 hr These alloys were Hastetoy X ttsynes alloy 188 and rnconel 718 and they contain approximately 205 Cr Other juvestigstors have reshyported weight losses due to loss of chromium in steam at high temperatures I i is probable that these aHoys would have continued to lose weight if the steam conshyditions had not changed new specimens of some of the aloys WW be inserted in the lest facility when sieam conditions improve
MS
t I t OBSERVATIONS OF REACTIONS IN METAL-TELLURIUM-SALT SYSTEMS
J Brynestad
Several criteria must be met for a good screening test system for the teflurium corrosion of Hasteloy N
1 The teflurhun activity must be appropriate reproshyducible and known
2 The tefflurium must be ddivered uniformly over the sm|jie surfaces and at a rate sufficient to prevent excessive testing times
3 Preferably the system should operate under invarishyant conditions during the test run
4 The system must be relatively cheap simple and easy to operate
in the MSBR the production of tellurium per time unit wnl quickly reach a constant value and in due time a steady state will be reached where telurium is reshymoved from the melt at a rate that equals the rate at which tellurium is produced
i to reacting with me Material of which the circuit is constructed leBunum could be reshy
moved by several means which mdmfc the foetamug
1 The | ining system Since the MSBR is to be equipped with a pm ceiling system to remove Gemm product telufium might be effectively removed from the salt by appropriate measures
2 The gas phase If the gas phase is contacted with a getter such as dumnium wool the tchwrimn activity m the men ought be kept dose to that defined by thelaquo
^Cr TTe(k)^ TeltgH ACrlts)
Thu activity is sufficiently low that Hastdoy N would not be attacked
3 A getter immersed in the salt mdt Obvious disshyadvantages of this arrangement would be the probshylems of mass transport in temperature gradients and the lack of a candidate material
Until the steady-state condition in an MSBR is more dearly defined it is impossible to state the likely tellushyrium activity It is only known that in the MSRE stanshydard IfasteOoy N was embrittled (probably by tellushyrium) In the MSRE the steady-state tellurium activity - if ever reached - probably was defined by gas phase removal and was likely rather high
Until the steady-state situation in the MSBR is deshyfined it must be assumed that one must deal with the MSRE condition under which standard Hastdloy N is embrittled In order to define this condition we have tested several systems with defined tellurium activities with regard to their behavior toward HasteHoy N
1 equilibrium mixture of C^Tejfs) + CrjTe4(s) 2 equilibrium mixture of NijTej(0j 41 at 7 Te) +
NiTe 077J(7I ^ 437 at Te) 3 equilibrium mixture of CrjTe 4(s) + CrTc6(s) 4 equibbriun lixture of Ni 3Te(s) + Ni(s)
The systems are arranged in sequence of decreasing Te 2
activity as determined by isopiestic experiments Typical corrosion experiments were contacted at 700degC for 250 to 1000 hr The arrangements were by isothermal gas phase transport of Te in previously evacuated sealed-off quartz ampuls by embedding the specimens in the mixtures and in the Cr2Tej-CrTelaquo and CrjTe4-Cr4Te6 cases by transport in molten salt
The most pertinent results are as follows
I Hasldloy N samples exposed to NiTej(s) bull Ni(s) (system 4) did not show intergranular cracking This is promising because if one a n establish a steady-
M l
dak luaawiun m which the telahaa activity is kwcr HOT OOI aefaed by das system staadanJ Haacaoy N wtl wot be eaaaittled
2 Sysaeas I awl 2 have teMaaa activities thai are loo high Ibex sysseas corrode Hasseaoy N sevcaeh water af the experiaeatal w w y a w i aad
3 Systea 3 fCrjTelaquolts) + CrTeraquoltsti SIUHH proaase as a iraariaa-deaivery actboa a aohea sansacc it B saffvseatry corrosive to cane aterpawatar cactoag of thk-caoy N b a docs aot fora acactioa layers
It is of value to note dot the systea Cr7Te(s| bull Ctls) has a tehaiaa activity that B mar lower thaa the systea NiTe2(s) fifs) l as systea abo is proa-isag since lagh surface duoaaaa aiebt be used a a tdariaa getter a the fas phase Experiments are water way to measure the telariaa activities of the above systems
611 OKRATIONOF METAL TEJXURJUM-SALT SYSTEMS
J R keissr J Brynesud J R DiStefaao EJLawrcace
The discovery of Jtatk intergranular cracking of HasteBoy N parts of the Molten-Sail Reactor Experishyment which were exposed to furl salt led to a research effort which identified the fission product tellurium as the probable cause of the cracking Experiments showed that HasteBoy N specimens which had been dectro-plaied with tellurium or exposed to telariaa vapor exhibited shallow intergraniaar cracking like that of specimens exposed in the MSRE Subsequently a proshygram was initiated to find an alloying modification for HasteHoy N which would enhance its resistance to teiu-rium The resistance of these modified alloys to crackshying is measured by exposing specimens to leaiirium vapor deforming them and then evaluating their surshyfaces by metallograpruc and Auger methods However the chemical activity of tellurium in these experiments raquo significantly higher than it was in the MSRE In order raquoo simultaneously expose specimens to the combined corrosive action of molten fluoride salt and telurium at a more realistic chemical activity a method is being sought for adding tellurium to molten salt in a manner that would simulate the appearance of lefurium as a fission product Experiments have been started that wia permit evaluation of several methods to determine whether they will produce the desired conditions
61 II Teaaraan Expcnacatal Pal I
Tellurium experimental pot 1 was built to evaluate the use of lithium telluride as a means for adding lefu-
riaa to safe Has pot laquoRg 632)aVws t d a a a lobe
BaaaaWC PJKBTBBH t a W t m a f f e a l tan a a r a n f H M K I BBBEBY a a a V aj w^ laquo ^ n i w araquovraquo ^ ^ p a t s waaaaajaa ^^a avaa BPUiawavww a a wuvu a a a i aaawaa
through Tefloa seals aad are used Or delect aad aeaa JK
14 The Nrtimdash laquo fan far As nacnacw raquo raquo fnfmt4 bully vannr t JHB ncaacny i mc ootiiuuucvKai B a M i i o o bull a t m4t traquo aryci raquo4 ) b M r
102
I bull UF-lef -ThF 4 (72-16-12 mdk mi m tern- A rfastetoy N pat was filed with the salt LiF-ftcfV latoSOTC ThFlaquo (72-16-12 aaok ) mi the temperature conshy
trasted at 700C After a sample of the salt had been lixTe which w pscpMcd hy the tafcea CrTelaquo was added mi a M I Hasteaoy N sheet
(Sect 31) hat i i i j two pdhsts specimen was inserted hMo the salt After 170 hr the a total of 0170 g of l i jTe were added to tjrrrwnrn was reamed and after 250 hr a salt simple
I of saw taocaoJwwkji enmamiua of the salt wax taken The teaaperatare was thea lowered to 650degC of oar ftadynra Chtaaitijr Draw gave aad a day user a sab sample was again takca This of the preseace of irlmiiia (Sect S3) xoacace was thea repeated at 600C Next the salt
dace aancIiiTepdkts west added aad te-ptrataie was rawed to 7O0C Cr Te was added a sawffc of Ae salt was takes for choanal analysis aad aaother Hastetoy N spedaaea iasertcd Ihe sped-Thre- addaaoas of CrF 2 totaling IJ2 g were thea a n was reasoned aad sah samples were tafcea under the aanle roauaed hy the aaaaaoa of theee awe li jTe same tjaw4eaagteratare coaditioas as discussed abouc
A anal iddirtja i nailing of 02 g of 10 was The two Hasteloy N spediaeas we submitted for Anger examination No were detected bat twdeace of tdariaai in the grain
foaad (Sect 612) The results of thr of the salt snaade are shown in Table
614 Tcaaraaa ooaceatratioas at 700C were not as bjgb as was expected bat the tact that some tct-irium was ia solution is deaaoastiated by the teHariam found oa the tpniannt Addrtioaal CrjTe was added to the
two salt samples were take lYriincaary that the soJatioa any not lane been
i the first series of salt samples was ulten the solafcarry measurements two tensile
icre exposed to the sah-CrjTcj solution Both specaaeas oae of rcfabr Hastcloy N and oraquo of lift Mraquo-07 Ti uwdrfied Hasteloy N showrd a
after 500 t_r exposare at 700C After iheregabr Hastetoy
N jpuinun was obatmd to lane agaificaatty more aad cracks than dhJ the modified Hasteloy N sped-
i (Sect 614)
r6M
611J
The adfciua of a CrjTty or CrgtTlaquo4 at anj stall aaothtr awaVod for
toaHaamMSMfanadtiraaesceai of ehraawam idhaldt is bullanafaajsi aat acttwiy of
at the adt wM he otnunaat pro-
To at which canter of thaat chro-
bullw wWwWwaPpPIbull VraW) ^ppaaar bull ajwPTff
of the chromta Mftaridat as s faac-
Tlaquoaa rnmauddNoanan M )
Moaa^aVStwMw bullnoTci After
OTe After
Ctlt tUHiam
im Tlaquo 5 0 4 4
Tlaquolt5 Cr7S
Tlaquolt5 CrlaquoJ
656 Tlaquo 151 CrIOS
Te75 Crl20
tan Tlaquolt5 rr
Tlaquolt5 OBJ
103
The experimental assembly is being used to expose standard Ifasteiloy N specimens to salt containing Cr Tej to obtain data on the extent of attack at 700degC as a function of time
611J Telwnum Expctunxwtal INN 2
When a technique for introducing telurium into salt at an acceptable chemical activity has been developed a method will be needed for exposing a large number of specimens to salt-tellurium solutions A Urge experishymental pot has been constructed for this purpose The pot has a stirring mechanism facilities for introduction of electrochemical probes and sufficient accesvi to allow dmulianeous exposure of a large number of specishymens Operation of the system will begin when a satisshyfactory tellurium addition technique is available
612 GRAIN MUNDARY EMHtlTTLpoundMENT OF HASTELLOY N BY TELLURIUM
R E Clausing L Heatherly
Auger electron spectroscopy (AES) is a powerful technique for studying grain boundary embrittlement of Hasidloy N by tellurium The recent development of the technique to permit AES analysis win a small-diameter (--5-fi) electron beam to excite the Auger elecshytrons of a specimen surface has made truly microscopic analysis possible1 5 The development of techniques for scanning the beam and the development of electronic data processing equipment have continued to be a censhytral pari of our efforts As the techniques improve our ability to see the details of the telurium embrittlemenl process improves dramatically We can now not only provide a qualitative image of the elemental distribution on intergranular fracture surfaces at a magnification of several hundred limes but we can aho provide a semishyquantitative elemental analysis as the beam it scanned along a line across the sample However it is not presshyently practical to provide a quantitative analysis along a line across an rntergranubr fracture surface since Auger intensities at each point OR a rough surface vary accordshying to topography This effect can be corrected in prinshyciple by a normaliation technique but data for each point must be normuhad mdrvKJuaRy and the present equipment cannot handk the volume of data required The data presented below are typical of several samples of lefluriurn-envbrittled HnHcRoy N that were examined recently These samples are being studied in various
15 R I ltlMlaquonf ami I Ikjihrrly VWT ftn^wm Srmi mmu rmtr Rrp fth J bulllt ORNI -5ltM7 p MM
pans of our previowtty outlined efforts to understand the tellurium embrtttkment of nickel-based alloys The sample chosen for the present discussior demonstrates our state-of-the-art capabilities and limitations and at the same time provides some new insights into the nature of the tellurium embrittlement of Hasteloy N
A sample of Hasteuoy N that had been exposed to tellurium vapor at low partial pressure for SOO hr at 700degC was fractured in the AES system and the resultshying fracture surface was analyzed using Auger electron spectroscopy The fracture surface is shown in Fig 6 3 3 The scanning electron micrographs made by Crowe reveal that intergranular fracture occurred along the edges of the sample and that the central reejon faded in a ductile manner One fairly large area of ductile shear can be seen Three types of Auger data presentations are used below imaging line scans and selected area analyses The first is qualitative while the second and third are progressively more quantitative
Figure 634 is an image obtained using the scanning beam in the AES system and the absorbed sample curshyrent to produce the image contrast It is similar to the scanning electron micrograph (la) but because of the larger electron beam and the different method for proshyducing the image contrast the resolution in Fig 654a is poorer and some distortion is evident Nevertheless it is relatively easy to correlate the features shown in Fig 634a with those in Fig 633a Figure 6346 is an image of the same area shown in Fig 634a but with image contrast produced by the tellurium Auger signal A careshyful comparison of the areas of high tellurium concentrashytion with the areas of intergranular fracture shows that a good correlation exists between the two No telurium can be detected in the regions of ductile or shear fracshyture Figure 6 3 5 b a series of line scans showing the peak-to-peak intensity of the Auger rignah for nickel molybdenum chromium and tellurium as the electron beam was scanned along the path shown by the bright line Hi Fig 654a Some of the observations that can be made are (I) The intensities of the Auger signals are influenced considerably by topography that is some features such as the shear region between feature gt and the ieRuriumlaquombrittled region below it show lower Auger emission for al dements (this dependence on topography accounts for much of the jagged nature of the line scant 12) The lefurium concentration is quite high in the region of mtergranuiar fracture near each original surfaor ltJ| There is a definite tendency for the concentration of molybdenum to be higher in the regions of intergranular fracture (41 The nickd and chromium concentrations are in approjumatety the same ratio throughout the scan
104
ltaraquo 2nox ifrgt sonx laquorraquo nmraquolaquo wgt torn lto jonox Tt
105
Y-133510
Crack
Te Ertrittled
I i raquo i gt MICffOftS 375
j j TTT90raquoi i i S i i i r r i I005 INCHES 0015
F fcM MI l i w u i rtmw bull laquo raquo laquo gt mm to raquo AES Fht brnrfii wiiiul law dnraquoraquo the path irf ibr IMW laquo M 4laquol HJaMMrt ftftom in laquo fc-35 (M h M p e f otoMawajgiMM
NJ 4t M M n Aapjf bull bull bullgt pMaJwt nartmrt The onkriiiM fraai tuwJjiy ngtam m i to th
106
Traquo-laquo4T
Flj tSS Anger ajnJ Menrities for scans atony Ike path wdicXcd sn Fjsgt 6S4 The vertical axis is displaced and the vertical scales arbitrarily varied to permit a qualitative comparison of the variations of Ni Cr Te and Mo as a function of distance along the scan line The tones and features identified along the horizontal axri are also identilied in Fig 6_S4raquo and c The AES analysis of the regions bbeied area I area 2 and area 3 are given in Table 615
Another observation based on the detailed examinashytion of this and other samples is that the tellurium conshycentration hi the grain boundary is not a monotonically decreasing function as one proceeds inward from the original surface On nearly all of the embrittled samples examined thus far the tellurium concentration is uni-formnJry high throughout the embrittled area as for example is shown on the right in Fig 655 (The signal intensity on the left is strongly influenced by toposhygraphy- If this effect were removed by a normalization process Ms area would have a more nearly uniform composition similar to that on the right) The high relashytively uniform telurium concentration in the embrittled regions suggests that either a particular grain boundary phase of fixed composition may exist or that the tellushyrium atom fill all of the appropriate grain boundary sites in the embrittled region Sputtering this fracture surface (and those of similar samples) to a depth of a few atomic layers (3 to 10) reduced the tellurium conshycentration to below I at showing that the tellurium is concentrated very sharply in the grain boundary it is
therefore unlikely that the tellurium present in the grain boundary exhibits the properties of a bulk tdluride The molybdenum concentration remained high during sputtering operation indicating that the concentration of molybdenum is high in the bulk phase perhaps in a phase that has precipitated in the grain boundary
Table 615 shows quantitative selected-area analyses made in the three regions of the sample indicated in Fig 654c The compositions have been normalized to equal 100 at in each row The three rows for each area are obtained from one Auger spectra but some elements were ignored in the first two rows to make changes in the relative amounts of the other elements more obvious These results confirm the above conclusions and show ( I ) that tellurium is present in relatively large amounts in the embrittled regions and (2) that area 3 which is near the extreme of the depth to which the tellurium penetrated contains about as much tellurium as area 2 which is located near the center of the upper embrittled region Regions 2 and 3 are both enriched in molybdenum and carbon M indicated in the line scans
107
r4IS Cuaiummnofi ofaHamdmyNa
tor Suffer at 7 laquo r c
Rezwn Composition in laquo5r
Ni Mo Ct O
Composition in the lower repon area 3 imiertranitU fracture)
Cohipositioi in ocntral region area I (dacine lnlaquoiuregt
Composition in ike upper repon arcs 2 imlergwiutar fracture
70 1 11 M 1 10 9 40 II 6 6 75 16 9 75 16 9 61 13 8 64 25 12 58 23 II 8 42 17 8 6
33
13
I I
Areas identified in FBJ 6-54r The composition in each row is normalized lo cquai 100 at ri The three rows
lor each repon are from the same data but are normabted so as to make changes bulln retain amount of the dements more obvimn For convenience and consistency in repot inc data we astame the AF5 spectra tfaol Pabnbetf et aL Htndhook of Anger Electron Spectroscopy Physical Electronics Industries Inc Fdiru Minn I972l are accurate and directly applicable to our data Elemental sensitmwes are taken directly from the spectra presented m the handbook with no attempt lo correct for chenaca effects line shape matrix effects escape depth or distribution of dements as a fraction of depth in the sample The analyzer used is Varian model 981-2707 operated with an SOOOeV electron beam energy
The above results suggest the need for a detailed examination of the causes and effects of the high moshylybdenum and carbon contents in the grain boundary region and abo an examination of the irnphcations that the presence of a two-dimensional tellurium-rich grain boundary phase may have on the time dependence of tellurium penetration into the alloy
613 X-RAY IDENTIFICATION OF REACTION PRODUCTS OF HASTELLOY N EXPOSED TO TEIXimiUMCONTAlMNC ENVIRONMENTS
D N Braski
Hasteiloy N and several modifications of the alloy have been exposed to tellurium to determine their rda-ive susceptibilities to intergranular cracking Different nethods for exposing samples to tellurium have also
been studied in an attempt to develop a suitable screenshying test for the alloy aVvctopmenl program Some specishymens were exposed directly to tellurium vapor at 700degC while others were subjected io attack by nickel or chromium teBurides at 700 and 750V respectively This section presents the results of x-ray diffraction analyses of reaction products producerl during the tests Knowledge of the reaction products akts in evaluating a
given method of tellurium exposure and may provide information relating to the mechanisms of intergranular cracking
A number of Hastefloy N tensile specimens and flat x-ray samples were exposed to tellurium vapor at 700 SC for 1000 hr in an experiment conducted by Keimers and Valentine The specimens were positioned in the top portion of a long quartz tube having a smal amount of teiurium at the bottom The tube was evacuated backfilled with argon and placed hi a gradient furnace with the specimens at 700C and the trtiiium source at 440C With this arrangement teuurium vapor diffused upward through the tube at a rate dependent on the temperature difference between the specimens and the tellurium CM)Xgt5 mg TehrV At the end of 1000 hr exposure the specimens were covered with a very fine hairlike deposit similar to that observed previously in creep tests at 6 5 0 C 7 The results of x-ray diffraction analyses on these deposits are given in Table 616 The first alloy listed is standard Hasteftoy N while the other three have titanium and niobium additions The main
16 A D Keimers ami D Y Vatentme MSK Ammjm Semi IMII rrogr Rep Feb 2S 1975 ORNL-5047 pp 40 41
17 R F GeMhach and H HensonMSK hvpmm jViinwm frogr Hep An J I 1972 ORNL-4832 pp 79 86
108
TaUcfclt X-faydifTrartiMi malts fori IO0O brat 700 C
Hat number t lt aftoyinx
additions to nominal HasteBoy N composition
Method of tellurium expovire
Surface reaction products
405065 None kelmervVaknime experiment^
NiTe CtJe
472-503 M r Ti kctroerv Valentine experiment4
NiTe
470-835 0711 Ti 261 Nb Kebners-Vakn line experiment
NiTe CrTe
IK) 841 Nb Kdmers-Valeniine experiment
Ni rTe
474-533 201 Ti Brynestid low Te ac irrily exposure NiTets) + Nitsgt
NiTe unidentified substance
405065 None Bryncstad LiO + CrTe
N i T laquo + N i T e
V D Kdmersaad D Y ValentineMSR Fran Srmunnu Prop Rep Feb 28 1975 ORNL-5047 pp 40-41 J BrynestadVSR Prognm Senaamu Prvgr ltep Feb 28 1975 ORNL-5047 p 102
reaction product was NijTe 2 which was detected on the surfaces of all four alloys (NijTe was found on earlier samples exposed for shorter times in the same apparatus) X-ray lines which could be indexed as CfTe4 were also found on standard Hastelloy N and on the alloy modifkJ with 071 Ti plus 263 Nb The Cr jTe 4 interplanar spacing and relative intensities were calculated by H L Yakel Metals and Ceramics Divishysion from the crystallographic data in ref 18 The presshyence of CrTe4 in the reaction layer is reasonable beshycause both chromium and tellurium were detected pre viously on Hasteiloy N exposed to nickel telluriddes by electron mkroprobe analysis1 In addition chromium tdlurides were previously identified by x-ray diffraction on Hastelloy N exposed to tellurium vapor17
Brynestad20 exposed 2 Ti modified Hastelloy N specimens to a low tellurium activity (Ni3Te + Ni mixshytwe) at elevated temperatures The specimens were first placed in a quartz tube and the Ni JTe 2 + Ni powder mixture packed around the specimens The tube was then sealed off under vacuum and placed in a furnace at 700degC for 1000 hr The reaction products obtained in this test also contained NijTe2 but the remaining four lines could not be satisfactorily indexed to any of the
18 A V Berfaul G Rnull R Aleonard R Pauthcnct M CVvTctou and R Jansen Structure Magnet iqucs de CtX 4
raquoX = S SeTeh Phvs Radium hi)582 95 (1964) 19 D N Braski O B Cavin and R S Ctmae MSR Prltt-
gnm Semtannu Fmgr Rep Frh 28 1975 ORNL-5047 pp 10$ 09
20 J BryncMad MSR Program lemktnnu Pmtr Rep Frh 28 i975 ORNL-5M7 p 102
Ni Cr or Mo tellurides The unusually broadened x-ray diffraction peaks suggest that a complicated teluride such as Ni-Cr-Te may have been formed In another tellurium experiment Brynestad exposed a standard Hastelloy N tensile specimen to a melt of LiCI containshying Cr 2Te 3 (solid) at 50degC Some Cr 2Te dissolved in the LiCI melt and reacted with the HasteUoy N After 146 hr the tensile specimen was removed and the flat surface on one end was analyzed by x-ray diffraction The results (Table 616) showed that Ni3Te2 and NiTe0 were produced
In summary these tests have shown that the primary reaction product between Hastelloy N and tellurium near 700degC is NijTe X-ray lines corrsponding to Cr iTe 4 were also present in patterns from the surfaces of several Hastelloy N alloys exposed to tellurium vapor at 700degC Exposure of Hasteiloy N to tellurium at low activities (NijTe2 + Ni mixture) may have produced some complicated Ni-Cr-Te compounds in addition to NiTe2 as evidenced by the unusually broadened x-ray lines
614 METALLOGRAFHIC EXAMINATION OF SAMPLES EXPOSED TO
TELLURIUM-CONTAININC ENVIRONMENTS
H E McCoy B McNabb J C Feltner
Several samples of modified Hastelloy N were exposed to tellurium-containing environments They were deshyformed to failure at 2SdegC a procedure v-hich forms surface cracks if the grain boundaries are brittle a
109
metallographk section of each was prepared to detershymine the extent of cracking- These tests hawe two objecshytives The tint is to dewlop a method for exposing samples to leBurium to produce a reaction nte comshyparable to those anticipated for an MSBR This rate is thought to be a flux of teOurium of about I0 1 atoms cm 1 sec- The second is to compare the cracking tendencies of arious alloys of modified HasteBoy N
A new technique developed for measuring the extent of cracking is more nearly quantitative than that used previously In the new technique a mounted and polished longitudinal section of a deformed specimen is viewed on a standard metallurgical microscope The eyepiece has a fiar which can be rawed to various locatiom in the field being viewed The filar is attached to a transshyducer which produces an output voltage that is a funcshy
tion of the location The output signal is interlaced with a scull computer which WH on command compute crack lengths and several statistical parameters The information is displayed on a teletypewriter The cracked edge of the mounted specimen is scribed every 01 in_ and the operator measures a l cracks in successhysive 01-in intervals untl at least 30 cracks have been measured The computer then calcinates and displays the average crack length the maximum crack length the standard deviation and the 95- confidence interval A typical scan requires about 10 mm and is considershyably faster than other methods used thus far
The experimental conditions associated with the ten experiments to be discussed in this report are summashyrized in Table 617 The chemical compositions of the alloys studied are given in Table 618 In all cases the
T J U T pound I 7 Cenoal4cxiiftmm ofTe-HaMenoy N a y w t t
Experiment IXcsipna (km Experimenters Exposure
conditions Alloys
bullMinded Genera
75-1 Brynesud UCl + Cr Te for I 4 6 n r a l - 7 5 0 C
405065
75-2 Krimcrs Tc vapor for Valentine |l)00 bral 700 C 405065
470-835 472-503
ISO
75-3 Bryneslad 250 hr at65ITC 405065 pa-kedin( r Te 474-534
474-535
75-4 Bryncstad 200hraf 700 C packed in Cf Te
405065
75-5 Biyncstad 504 hr at 700 C 405065 Keiser in s i t bull Cr Te 470-R35
75-6 Brvnestad 000hra l700C with vapor above Cr Te 4
405065
75-7 Brvrrslad 1000 hral 700 C with vapor above Cr Te
405065
75-8 Brynestad 1000 hr at 7 0 f l T laquo i l h vapor above J gt nH-kel tellurides
405065
75-9 McNafcb 250 hi al 7laquofC in 405065471-114474-534 McCoy vapor above Tc al 474-5356006006263
300 C I H 237295 297 298 303305306345346 34734821543469-344 469-648469-714470-786 470-835
75-10 McNabb 250hra l700 C in 40506521543 345348 McCoy vapot above Te al
300C 4 1 1 4 1 laquo21424425
Heavy reaction lay en
Whisker growth evidence of inhomopenoas reaction withTe
Heavy reaction layers
Heavy reaction layer
Reaction layers
No visible reaction ayers
Shallow reaction layers
No visible reaction layers
No visible reaction layers
No risible reaction layers
See Table 618 for chemical compositions A D Kilmers and I) Y Valenlnc M$R Program Srmimmi FriffT Kip Feb -X V75 ORNI-5047 pp 40 41
110
t6lt
Heaimoabei Mo Cr Fe Ma C Si Ti Mb At Of her
62 134 752 a 020 0042 001 a 19 63 145 7 J 3 a 020 0135 001 a 25 l raquo 12 70 0040 022 0046 OJOI lt002 184 ISI IS 684 0054 0-23 045 001 050 185 003 W 237 20 67 43 049 0032 m 004 103 lt0-05 295 14 806 402 0 28 0057 lt002 lt002 085 0 0 5 296 15 809 396 028 0059 lt002 lt002 12 02 W 297 29S 303
2 1 20 20
70 70 70
40 40 40
02 02 02
0 0 6 006 006
002 0J02 0J02
024 lt00I
049
057 2J0 0J4
305 12 825 416 022 0072 009 088 I J 306 06 804 311 018 0065 027 001 OSS 345 IJO 71 38 026 005 022 002 045 346 110 67 37 018 005 048 002 049 347 20 7 43 025 005 047 lt002 088 34S 411 4 l i 42 424
20 20 20
120 120
72 70 70 70 70
007 a a a a
019 02 02 02 02
005 005 005 005 005
047 e a a a
lt002 a 1 0 219 18
042 115 113 104 134
007 010
42J 120 70 a 02 005 a 19 048 008 405065 160 71 40 055 006 057 lt00I a lt003 472-503 129 679 O089 lt00I 0066 0089 216 005 009 471-114 125 74 0062 002 0058 0026 175 a 007 474-534 1166 712 006 lt00I 008 003 20rgt a 053 014
0013 La 474-535 1179 730 005 lt00I 008 003 213 a 055 010 W
0010 La 003 Cr
600600 160 80 019 027 ltlnconcl600gt 469-64 128 69 030 034 0043 a 092 195 a 469-714 130 85 010 035 0013 a 08)) 160 a 470-835 125 79 068 060 0052 a 071 260 a 00311 Hf 40-76 122 76 041 043 0044 a 082 042 a 0024 Zr 469-344 130 74 40 056 011 a 077 17 a 0019 Zr bull21543 124 73 004 008 0050 0019 a 0 7 002
Not analyzed bur no intentional addition made of this dement
Not analyzed but nominal concentration indicated
sample was a small tensile specimen 56 in in diameter X 1 in long having a reduced section in in diameter X I in long All specimens were annealed I hr at I I77degC in argon prior to exposure to tefliirium The results of crack measurements and data resulting from the tensile tests at 25degC that were used to open the embrittled grain boundaries are shown in Table 619
Experiment 7S-I was run by Brynestad and involved a sample of standard Hastelloy N that was immersed in LiCl saturated with C r T e for 146 hr at 750degC The specimen formed a heavy reaction layer (Table 6 7 ) but lost weight (Table 619) Figure 656 shows that the reaction was rather extensive with some obvioia grain
boundary penetration which resulted in extensive crack formation in the deformed section The extent of reacshytion in this experiment was higher than anticipated for an MSBR and therefore it is not believed that the experimental conditions employed constitute a good screening method
Experiment 75-2 was run by Kelmers and Valentine and the detailed results were described previously2 All samples lost weight in this experiment (Table 619) Although the samples had more reaction product en
21 A D Kelmer ind D Y ValentineWW Program Smi-anmi Progr Rep hth 28 1975 ORNL-5047 pp40 41
Tabic 619 Inlf(granular vracfc formation anrt loniU propcrD of raquomnllaquoraquo oPlaquoraquovd In ulltMlum and ilralnad lo faHurv al 25 V
ffimmti H M I MMttof
CilaquockiMui k |0gt
C m k t f w C i K k t c m
D t p In ) SlWMbi 4fvulMgtn
1raquogt
CMflOIIWt W I U M I
I M I
W f laquo k l bull lung lmlaquol
VMM t u t u
ltbullbull rail
U I W M I f M M HltMH
t l O 1 ptl)
f l M I I M f H l t U
lt I 0 p i l l
U m f w m f lMUt lWH 4 I 0 ^ I raquo
P l M I W f HIM
K n l i w i i M M M M
11 MMraquofclaquo
H M I MMttof CilaquockiMui k |0gt
C m k t f w C i K k t c m A M I i f M W I R H U H
SlWMbi 4fvulMgtn
1raquogt
CMflOIIWt W I U M I
I M I
W f laquo k l bull lung lmlaquol
VMM t u t u
ltbullbull rail
U I W M I f M M HltMH
t l O 1 ptl)
f l M I I M f H l t U
lt I 0 p i l l
U m f w m f lMUt lWH 4 I 0 ^ I raquo
P l M I W f HIM
K n l i w i i M M M M
11
5 1 40505 ) | lgt 111 101 lt 1 7 1 4 ) 1 I T 4 1 1 1 4 ) M i l gt I 4 HI raquoJ-1 4 0 5 0 5 5 ) 0 1 1 4 t gt 7 5 7 1 1 1 4 5 1 0 SI 7 1 ) 4 7 I I 71 4 0 4 4 1 1 43 1
470-1)5 17 A t 1 7 7 0 I S 4 4 1 1 1 7 7 1410 l ) t laquo 4 1 5 44 0 ) S ) 4 7 ) 5 0 ) 100 I I I gt)) raquo7 0 1 4 I I sraquolaquo 1 5 ) 1 1 1 ) 0 ) l lt 4 0 4 410
iao t ) 15 1 4 ) 0 1 D l A l 47 5 4 5 1 1 4 ) U S I M l ) t 1ST 7 5 1 40515 140 laquo5 17 1 4 1 1 0 17 117 4 7 uto 1 0 0 4 0 1 414 4 1 4
474lt5)4 110 17 145 1 7 4 5 1 4 145 S t 114 0 1 0 0 411 441 S I T 4 7 4 5 ) 5 1 ) 0 bull I 1 0 ) M 4 5 4 1 1)1 4 S 4 not laquo 7 4 7 4 lot S 4 )
7S-laquo 40505 4 1 0 5 7 0 11114 l raquo ) S l 1 1 1 1 1 1 ) 5 11 ) 15 1 bull raquo I 7 7 1 1 ) l 44 1 44 0 10) 7 I N M ) H I 1 1 1 gt I 0 ) ) i ) 1 4 4 1 4 4 1 0 7 5 5 405115 170 14 4 1 5 raquo 0 I S S 1 bull 0 1 5 0 111 1 1 1 7 ) gtS ) 7 1 1 1 1
4 7 0 laquo J J 10 71 ))) 14 7 1 0 1 I t S I 5 1 1 I M 1 I M 7 17 0 ) 7 1 1 4 7 - 40505 115 15 I ) 1 1 4 1 ) 1 4 4 0 bull 001 S i t 1 1 1 ) 1 1 7 1 4 0 4 4 1 0 ))raquo 7 J 7 40505 510 )ogt 4011 1 0 1 4 1SS k i t 1 1 4 ins ) I 7 ) 4 ))gt 7 ) 1 40505 ) 0 141 5 5 bull lll 1 1 7 ) )raquo) Sl l 1 1 ) 1 1 1 7 4 4 0 0 414 5 1 7Jraquo 40505 H O 141 4 1 7 5 ) 151 I I I 7 5 1 1 1 7 ) 1110 M S 41 1 gtraquo4
4 7 1 0 1 4 l i 7 ) ) 7 4 )laquo I D 4 4 bull 1 4 4 7 1 1 ) 4 105 0 laquo raquo l 5 4 1 4 4 4 7 4 5 ) 4 ) 0 14 1 1 5 4 5 5 107 ) 1 7 I t l i t 1114 4 gt gt 45 S 411 15 140 I S 10 1 J M raquo l J7 0 5 1 5 1114 I D ) 4 t ) 4 1 ) 4 7 t HI 15 10 1 7 1 U I laquo I I bull ) 0 )raquo 1 0 1 7 4 U l gt 7 I S T )
M S 100 )raquo )raquo 4 l 1 1 1 1 4 bull 0 7 1 1 7 I I 1077 M l 41 I 4 raquo ) H t i l l ) 1 0 7 441 100 ) S bull 0 4 551 I l l 1117 41 1 44 7 4 7 1 M l 4 l I S ) l i 0 ) M l 1 1 ) 4 1075 4 1 5 4 5 511) J41 170 0 raquo I I I ) 7 ) l i i bull 1 S l l 1)1 1 l l t l 4CI 4 ) 1 4 ) 50 450 177 11 o 1 7 7 ) i i bull 0 1 too 1)00 1 1 1 17 4 4UI 4 ) 4 50) 450 l lt 1 4 1 1 raquo l i bull 1 1 I t 1 111) 1100 471 445 4 0 raquo 7 J i l l 111 1 1 0 4 1 0 1 1 u bull 1 1 t l 1 l i t ) 1 1 7 1 ) S gt ) T 4 4 1 5 15 15 10 10 1 1 7 ) i s 1 5 5 ) 5 1 1 ) 1 I M S 4 gt ) 4 4 4 4 4 1 )7 IS )) 14 1 ) I S I S i 0 5 1 4 l i l t I M S 4 ) 5 4 4 ) 4 4 505 H O 141 I t ) 1 7 1) 1 4 bullUS 5 ) 1 D t S 1 1 7 ) 4 4 1 4 1 4 7 7 M l 1)0 D O 1 7 ) 107 bull 4 1 1 bull 0 4 7 1 ) l l ) t 1104 4 1 7 4 raquo 4 7 11 110 17 1 7 1 1 1 7 ) 7 7 4 M I 1171 m i 4 1 4 4 S I M S ] 10 11 1 gt 1 4 0 4 4 5 IS 1 5 4 7 117) 110 1 4laquoT SOT 4 1 1
) 440 17) 117 1 7 S ) 1 I S l l l ) ) 4 111 7 gt J ) ) l o 41S 4 4 4 1 ) ) 0 1 ) 0 I I I 4 ) ) 7 4 1 bull 0 1 I I 1)1T 117) 4 ) 7 4 1 445 4 7 | 4 1 ) )) 114 5 0 4 1 1 4 5 bull 0 0 1 4 1 1117 l i t ) 8 ) 7 Hi 4 ) 4 4 7 0 O J ) )bullbull 1 1 4 7 SO 1 0 0 ) 5 5 IJ75 1)04 414 477 4 5 4 7 0 7 t )) 1 ) 1 ) 1 5 7 1 14 S 7 ) 0 ) 4S l i t 7 1 0 7 ) 5 0 4 S I 7 40 1 4 5 4 4 )raquo 141 l 171 V I 1 ) bull 0 07 5 1 7 1 ) 1 1 1 1 0 ) I 0 ) raquo 7 414 4 1 1 5 4 ) bull5 )) I I 1 4 4 4 1 17 11 45 4 not M I MT 5 7 )))
75 10 40505 M O I ) ) 177 4 1 ) 7 1 1 bull 0 0 4 5 ) 1 1 ) 1 4 1 1 ) 0 4 0 4 gt I 4 4 0 415 ) 0 0 I I I 17 1 54 1 I I 1 4 1 bullOS S l l l i t a 1 1 7 4 7 411 411 415 140 5 1 1 7 5 1 0 1 ) 4 ) laquo 0 0 l t i l l i t ) I I I ) 4 1 ) 410 4 7 411 M O 1)5 M4 raquo0 l 1 0 1 1 4 0 0 ) sso 1 1 7 111) 4 ) 7 4 5 4 4 1 4 414 4 ) 0 1 1 7 501 14 1 0 0 ) bull 7 4 l ) raquo ) 1 ) 1 7 44 1 411 gtbull) 11 101 1 1 17 1 0 54 0 74 bull0 1 1 ) 4 1111 1 1 ) 0 4 7 1 SI 1 1 1 7 15 M 10 I I I 1 5 1 ) l bull 0 1 5 ) 4 m i 1117 4 1 4 4 4 4 47 ) 541 M 1 ) 1 1 M l 71 15 bull 5 4 1 i n 107 1 44 1 4 7 4 54T M 5 15 5 raquoraquo 141 gt) i n bull 0 0 1 5 1 1 1 4 1074 4 4 ) 4T4 4S4 415 M 11 105 117 5) I S bullooi 5 ) 0 i n I IS S H 4 4 44X1 411 1 ) 141 ) 5 laquo 1 5 1 bull 14 4 1 1 1 1 ) 4 bull T I S I M l 5 ) 4
4 1 1 5 4 ) 17 7 10 1 ) 7 I I gtraquo bull 1 4 7 ) I D 1014 S I ) 1ST 5 ) 7
4laquou i MM tun bull 15V al bull tiiaM M M ul 0044 Mgt 1uUl laquomlil raquof yfmmtri 1 1 l o t 1 )
112
raquo gt laquo laquo bull
(b)
pornnaof
0-010 in 0 25
U t a M H I i th) tdft oi ureaed poriioa of 1
llaquowraquoCr Tca i7Mrci IflOX
HkrltlaquoiE ytoT
one end than the other the extent of lt icjaunably uniform Typical plsotonucrognphs of the (oar materiab are shown in Fig- 637 Aloys 40506S (standard) and 472-503 (216 Ti) formed extensive cracks but aloys 470435 (071 Ti 260 Nb) and 190 ( I J49 Nb) were considerably more resistant to cracking
in experiment 75-3 three samples were packed in CrTe grannies for 250 hr at 650degC The samples formed heavy nonadherent reaction products and lost weight (Table 619) All three materials formed extenshysive cracks (Table 619 Pig 638) with the depth of cracking being slightly less in the two modified alloys (474-534 and 474-535) than in standard Hnstdfoy N (heat 5065) However the extent of reaction is too high under these conditions for the results to be meaningful
bi experiment 75-4 duplicate samples of standard HastePoy N (405065) were packed in granules of CrTe4 and heated 200 hr at 700degC The samples formed nonadherent reaction firm and lost weight tarshying the test (Table 619) The reaction layer and the
the reaction rate was un-of the exposure cnadnioni as a
bull Fig 639 reasonably high for a
k experiment 75-5 Iryneslad and Keaer two specimens to MSW fad carrier salt (c uranium) that was saturated with CrjTcj The exshyposure was for 504 hr at 700C These samples formed reaction layers but lost weight (Table 619) As shown in Fnj 660 both uatcinls formed reaction layers but in heat 470-835 (071 Ti 260 Nb) there to be less penetration of the rcactants aVng the | boundaries The standard Hastdoy N had regions where layers of grams dropped not during the exposure The number and depth of cracks in the sliessed portion of the samples were less for heal 470435 than for stanshydard Hastcloy N but both materials formed extensive intergranutar cracks
Since the samples packed in the various telurides reacted extensively several experiments were run Hi which the samples and the teluride were separated in
113
(a)
(b)
(c)
- r - raquo
(d)
0 25 MI FfcS7 SywiwuM fcmdasht tfmmmm IS-l wfcMl wmdash laquo y mdash lt iraquoraquofciraquo raquo w laquo r f p w raquo o r irtNilmi far I W H m 7 W C n i
NralltOAraquo5tfrlfcril4-Slttilt I TiM Ilwtf 47MJ5 llraquo7l-lt Ti lA SbKultkat MRi lA f r Hbt AlaquopoMwl lOOx
114
(c )
(laquo )
(f) raquo bull O O W f
0 2 S laquo raquo
fplusmn S Ipniawn tnm rxpummM 75-3 Packed m CrTe granules for 250 hr al 650 C and deformed lo fracture ai 25 f flaquoraquo Heal 405065 Msireaed thy hear 405065 Urevwd tei heat 474-534 (2091 Ti 00131 Lagt imlaquorclaquoed (ltraquo heal 474-534 tlrcuedfrgt hear 474-535 (2131 TiOOH La 0031 Claquolunlaquoreslaquodlt1 heal 474-SJS laquorevd Atpnnshed lOOx
115
3ampF
bull 025am bull
the reaction capsule In experiment 75-6 standard Hasteuoy N was reacted with the vapor above CrTe 4 at 7000 for 1000 hr The spedmen pined a amount of weight (Table 619) did not form a reaction layer (Fig 6J6I ) but did form extensile inter-granular cracks (Fig 6 J 6 I Table 619) Experiment 75-7 was run in the same way but Cr 2Te was used The sample tost weight formed a surface reaction prodshyuct and formed mtergranutar cracks when strained (Table 619 Hg 662) In experiment 75-8 the source of tellurium was two nickel leRuriJes fc and 7 i The specimen lost weight did not forn a TJIMC surface reaction producl and did form rnieigranubr cracks (Table 619 Fig 6J63)L From these experiments it was concluded that the tellurium activity produced by Ct Te 4 was likely that best suited for screening studies
ExpeiHMnt 75-9 included 25 aloys which were exposed to tellurium vapor at 7000 for 250 hr The weight changes covered a range of +84 to 74 mg with no obvious correlation between weight change and crack depth or number (Table 619) These specimens were sealed in four different capsules for exposure to tellurium and there were differences in the extent of discoloration of the samples These differences are likely associated with slight differences in the extent of reaction due to variation of the temperature of the tellurium metal in the various capsules Thus it is quesshytionable raquo to how far one should carry the analysis of the data from this experiment
Owe further problem coacernmg data analysis which applies equaly w d to afl data sets is the baas that should be used for comparison The number of cracks ami their average depth are two very important paramshyeters However it is possible that a Tprrimrn cm have a large number of shaaow cracks ( e ^ beat 63 Table 619) or a few rather deep cracks (eg heat 62 Table 619) The formation of intergranuiar craci of any depth is important because this may indicate a tenshydency for embrittlement The depth of the cracks ts important because this is a measure of the rale of peneshytration of tefurium along the grain boundaries Howshyever for a relatively short test time (test 75-9 (2S0 hr)) the formation of numerous shalow cracks may be indicative of a near-surface reaction which wil not lead to rapid penetration with time Obviously longer-term tests are needed to determine the rate of penetration of tellurium into the metal
On the basis of number of cracks formed the alloys in experiment 75-9 which formed lew than 40 cracks per centimeter were 345470-835421543 237469-714 470-786 62 295 and 348 The alloys forming cracks with an average depth of lt 127 u were 63 469-714 295 348 469-344 421543 and 470-835 Several of the alloys appear good on the basis of both criteria These alloys all cont in niobium and several contain niobium and titanium Another parameter used for comparison was the product of the number of cracks and the average crack depth The alloys from expert-
l i t
( bull )
laquo
ltlaquov
(c)
lt)
I 0 2 9 raquo raquo gt Figt iuM Senates from uteiiaini 75-5 Sanpln exposed to feci all sraraKd laquo-iih Cr Tc for 504 hr ai 700C and strained
lo fraclarc al 25T ltraquo Standard HasteHor N bullntlrencd shoaMer (Agt standard HasteHoy N stressed p(c length sfoning region where grains were urn dnrine tall cipotnre (lt-gt heal 4704135 10717 Ti 260 Nb) oatlrroed thoakitr ltltgt heal 47f 4J5 stressed portion Aspotahcd I00X
117
(a)
(b)
l f l laquo Q l n - | I 0 2 9 M I
Flaquofcl TtiMwi lUmBij X ( h w O W I I w lono br mi earned to fjUarc ut F4pr of MM icwd pvnna iraquo lt
1154k ampMOftrtrfKMe4 lo the of tiinaei porno As pufcihfi
CrTlaquo j i7laquorCfof IflOx
ment 75-9 are ranked on this basis (Table 6J0gt Stan-dard Hasidoy N raquo significantly different from al other heats on this basis There are latfe variations among the other heats but it is difficult to pick out general trends on the basis of niobium and titanium concent rations
Several typical photomicrographs of samples from experiment 75-9 are shown in Fig 664 No reaction films were visible on any of these specimens The picshytures show dearly the wide range of cracking experishyenced by the various heats
The mechanical property data show small but signifishycant variations in the yield and ultimate tensile stresses of the various heals (Table 619) The higher stresses are grnerolly associated with the alloys containing the higher amounts of niobium and titanium However the
high fracture strain and reduction in area for a l h-ais indicate that only very small (if any) amounts of gamma prime formed during the 250 hr at 700degC
In experiment 75-10 steps were taken to ensure that the specimens were at a uniform 700degC and that the tdurium was at 300degC The weight changes were very erratic and show no correlation with the number of cracks or the depth of crack formation (Table 619) A sample of heat 425 was included in each of the two capsules used in tins experiment to obtain some idea of reproducibility The reprodudbflity was reasonably good Samples o alloys 405065 298 295 348 and 345 were included in experiments 7 5 4 and 75-10 Heats 405065 298 and 345 in experiment 75-9 cracked more severely than in experiment 75-10 Alloy
l i t
V - t
(b)
I AW hr art in
021 uigtiiiwil75-7 iioafAtlaquo4acor A
Cr f e j i ltKraquo lt t t HMta
laquo bull - - Craquofc
ltW SS^j-^n-raquobull
WMMMCS at ItXfC foe IWO hr aa laquo u m lt lo f IflOx
0 2 9 laquoMi itmtm 7W San phi r^puraquorf to Ike
to) Mat of mmiiwmtd porta raquogt claquogt laquo tf bull gt mcfcd
puftimi A ^riuhfd
IN
ITS
note bull bull laquo tat tract tdncti0c4 I cy
roat i
H m i oaccatraaoa t 0
( - -
I cy
roat i
H m Ti Nb (Mm
5laquon 4ltI5laquoraquo5 371 3lraquo 0 3 5 027 Si 3195 474-534 2 4 9 01013 U 27 JO 471-114 175 247 303 049 OM 2400 3ttS OM 13 2249 29S 20 217 3 2-5 2 1 29 024 0 3 7 1993 347 raquoM 0 4 7 Si 1924 4S14M 092 195 I9 IO 474-5J5 213 0 4 4 L raquo raquo pound r IBSI M U M P27 15 C i 1453 I I I 050 l-SS 1304 344 04laquo 049 1292 49-344 077 17 9 9 345 045 ft22Si 4 M 237 1J03 409 49-714 0S0 tJampO 352 2 1 9 raquolaquo 4 7 M 3 5 071 IM 290 421543 07 179 4707S 082 0 4 2 101 295 0 M 3raquo 34S 062 047 Si
Set TjNe 1H lw drbiM cheiwcJ jiulvcs
348 was less severely cracked in experiment 75-10 and Nat 295 reacted similariy in both tests Such differshyences emphasize the importance of duplicating test results before making important conclusions
The alloys in experiment 75-10 that formed lt32 crackscm were 413 34 295 4 1 1 421543 and 345 Those with average crack depths s 109 p were 421543 295413 345 and 298 Again this ranking is of quesshytionable value because alloy 298 had the shallowest cracks of the 12 specimens but formed a large number of cracks In an effort to combine the factors of number and depth of cracks the two factors were multiplied and the alloys ranked as shown in Table 621 There is a very large step between alloys 425 and 298 and the better alloys appear to be ones containing from 045 to 20 Nb with titanium additions of 1 ^ or less
The tensile data show small variations but do not show evidence of embriitiemeni due to gamma prime formation during 250 hr at 700degC (Table 619) In specshyimens from experiment 75-10 the wide range of trackshying behavior is apparent (Figs 665 and 666)
These tests have shown that several methods are availshyable for exposing metal specimens to tellurium The metal tefluride Cr Te 4 has an activity most consistent with our estimates of tellurium activity in an MSBR Specimens can be exposed to salt containing CrjTe 4 or exposed to vapor above the compound Tellurium metal at about 300degC has a vapor pressure of about I X 10 4
torr and appears IO provide a tellurium activity comshyparable to that expected in an actual MSBR The specishymens exposed thus far show that niobium is effective in reducing the extent of iniergranuiar embrittlemenl of Hastelloy N
615 EXAMINATION OF TeCen-l
B McNabb H E McCoy
The TeGen series of capsules was designed for studyshying the effects of tellurium and other fission products on metals The fuel capsule is a Vi-in-OD X 0035-in-wall X 4-in-long tube segment of the metal under
120
( c )
I OOIOf - _ I I J 0 2 9 M I
Fagtfcj64- CumdashjMiiun of imdashapamdashtm cmfcif bull l l i jNluj H lyye aBoyraquolaquoaoraquod wgt partial aitmdash11 erf tdNrimdash of 10 vm fat 250 br at 7WTC aad iliaan lo fraroarc at 2SC ltlaquoraquo Standard Hasfcttoy N that 4O5065i (142 crjckwrn a depth 416 raquoraquo IM modified Hastcfloy N containinc 08S^ Nb (aNoy 295) (10 crackson a depth 101 raquogt laquorgt modified Hastdloy N conlaaunK 082^ Ti 0427 Nb (alloy 470-786) (13 crackscm a depth 86 it 00x
Table 6 J I Rmdashfciwiof materials from expuimoH 75-10
Product of number of cracks and average epth
rnns) Alloy
number Concentration CJI
cracks 1 x rntci cm
epth
rnns) Alloy
number Ti Nb Other cracks 1 x rntci cm
4512 424 18 134 3245 421 219 104 3198 425 198 048 2328 405165 2157 425 198 048
713 298 20 336 413 10 113 209 348 062 047 Si 133 411 115 106 295 085 76 421543 07 45 345 045 022 Si
See Table 618 r detailed chemical aiulyicv
121
ltd)
( f )
I 0 2 5 M B I
Ff 65 Miami tpwmriw from expuwww 75-10 SpccmKru were cxrvwrd f-r 5n hr ji nn lt- ilt ihr apltlaquor iNiw irlluintm meiil JI nit C bullgt All- 424 iM jllgtgt i i rIjHn 45 II allot 4050 in allm 45 (gt alloy ^gtraquo A pohthrd Wfr
122
-1MS7t
(f) laquo0fllQH -
025 mm Fig 666 Stimti specimen from experiment 75-10expoatd tot 250 hraf 700Cfo fherapor above idmriwn meM it 300degC
(j) Alloy 413 (ft) alloy 348 ic)alloy 411 Irfraquo alloy 295 (ltbull) alloy 421543 if) all 345 A polithed IOOx
123
study The capsule is partially tilled with the MSRE-type fuel salt and irradiated in the ORR to produce fission products
The first experiment of this series involved fuel pins made of Inconei 601 standard Hastelloy N and type 304 stainless steel and the irradiation time was such that the amount of tellurium produced per unit area of metal in contact with salt was equal to that at the end of operation of the MSRE Some of the details of the postirradiation examination were described preshyviously2 2 A typical fuel pin is shown schematically in Fig 667 The segments marked A w re subjected to tensile tests using the fixture shown a Fig 668 The mechanical property data obtained roai the rings and the results of limited irtetallograpic examination were reported previously2 z More detailed mctallographic studies have been completed during this report period The segments marked B were used for chemical studies The salt from each segment was analyzed and the fission product distributions on the tube surface and a short distance into the tube were determined from two successive leach solutions The first leach used a verbodt solution (sodium vtrsenate boric acid and sodium citrate) which should have dissolved only residshyual salt from the metal surface The second solution was aqua regia and the time was sufficient to remove about
11 B McNlaquohb and II I McCoy IfSR Pnrmm Sununnu Pnifr Rip Feh gt tv~ ORM-5ltMpp 12 6
I mil ot the tube Both solutions were subjected to various chemical procedures to analyze for various nuclides and elements These results are partially anashylyzed and the results for tellurium will be discussed The tube segments marked ~C were retained for posshysible future studies
61 SI Metafognpaic Observations
Photomicrographs ot the three materials in the un-deformed condition are shown in Fig 669 Numerous voids were present near the surface of the Incopel 601 specimen to a depth of about 02 mil Voids were likely caused by the removal ot chromium from the alloy via reaction with U F 4 in the salt The Hasldloy S vrction shows no evidence oi chemical reaction with the salt The type 304 stainless steel shows some grain boundary attack to a depth of about 0_5 mil This was likely caused by selective removal of chromium along the grain boundaries The features in the type 304 stainless steel appear much like shallow cracVs and may have influenced the number of cracks that were observed in stressed samples of this material
Composite photomicrographs of the Inconei 601 rings after straining to failure are shown in Fig 670 Rings 2 and 4 from near the salt-vapor interface exhibit some evidence igt( attack but the other samples are almost entirely free of indications of chemical reaction
Photomicrographs of the deformed rings from the Hastelloy N capsule are shown in Fig 671 The count
olaquoM-oac n-ot
TTPt DESCRIPTION M O USE
bull VW bullbull IMG FOR HCCMAWCAL PROPERTIES
B fOU L E A C N (2 STEP
C StCTiQM TO K RETAINED
mdash EH0CAR
mdash A - i
4 -2 A-3 AN0 SALT LEVEL
z~ -laquo A-5
- S A-4 A - mdash C
mdash A - a A - raquo
mdash A- IO
mdash C
mdash A - M mdash A-12
mdash C
mdash A-13 mdash A-14 mdash A-15 mdash 8 mdash A - W mdash EMC CAP
f 667 Schematic docram of individMl feci pm jhowing the locaftoMof tat specimen
124
metaliographic sample indoles the fracture and an adjacent segment Since the fracture occurred at difshyferent locations the metallographic specimen contains varying amounts of inhomagcneously deformed mateshyrial For example Fig 67 I f includes a very small segshyment of homogenously deformed material whereas Fig 6 71 includes a relatively long segment As shown by the photomicrographs in Fig 671 and the data in Table 612 specimens from the vapor region (2-A-I) the salt-vapor interface (2-A-2) and rite bottom of the salt (2-A-l6) cracked most severely Three samples from other locations formed shallower cracks It is not known whether these differences are significant
Typical photomicrographs of deformed rings from the type 304 stainless steel capsule are shown in Fig 672 These specimens located on the inside surface had shalshylow cracks with an average depth of about 04 mil (Table 622) These cracks were rather uniformly distrishybuted in the samples from all four locations As noted in Fig 669 the unstressed specimen also contained cracklike features having a maximum depth of about 05 mil Hence the cracks in the stressed specimens may simply be the result of furti opening of features that are likely related to corrosion
6152 ClKiMcal Analyses for TeBormm
The lube segments designated B-l B-2 and B-3 in Fig 667 were subjected to several types of chemical analyses but only the results for tellurium have been analyzed in sufficient detail to report at this time The results for the three pins are shown in Tabic 623 The
Ffc668
0 Fixlare for ft leatinj rinji
of crack frequency shown in Table 622 was made in an effort to detect significant differences in cracking among the various specimens These counts are subject to numerous problems the main one being the inhomo-geneous distribution of strain within the sample In deforming the ring specimens in ihe fixture shown in Fig 668 the small portions of the ring located between the two parts of the fixture likely deformed very unishyformly but this length is very short relative to the total length The part of the ring that contacted the fixture likely deformed in some areas but was restrained in other areas by surface friction from the fixture The
Taate 6 J2 Smmmmy of crack frequency aad depth inToflMtiM for riant from TcGea-1
facts alaquo W M M t ID ratae at 25deg C
from TlaquoGCM fad Specimen nu iber
Crack frequency
(crack sin)
Crack depth (mils)
Average Maximum
2-A-l 480 080 20 2-A-2 450 II 22 2-A-4 410 060 12 2-A-5 480 058 12 2-A-8 MO 046 10 2-A-l 6 380 14 25
Type 304 (taMeu tted
1-A-2 160 04 12 3-A-4 310 042 10 3-A-8 260 036 10 3-A-I6 202 037 10
125
(a)
-J
(b)
(c) 20 40
- L - 1 _ 0001
60 MICRONS lt00 mdash SOOX -
laquo20 40
INCHES COOS
Fjj 669 Undeformed rings (ample No 9) from each TeGen fad pin near the middle of the fael aalL (a) Inconel 601 (ft) HuMelloy N(r) type 104 ttainlets jteel A polished 500x
600 inn
Ffc 670 Sample from Incond 601 fad put from TeGcit-l Kir failure al 25deg0 Portion of specimen exposed to fuel salt is on the I location A A (laquo) location A-5fr) location A-8 () location A-16
BLANK PAGE
Sch figure
j J u i u m l i i -Mi iWWLltLiWHt
126
a ten from (he location shown in Figr 667 and deformed to tide of cacti figure it Location A - l tftgt location A-2 ( r )
J
127
I Fig 671 Samples from Hwribr N fuel pin from TcGcn-l I bMurr M 25 ( Portim of specimen epltlaquoeraquol ilt fuel sill ii on l l location A-4laquo) lotjlion A-5 ltr) loolion A- i ft loci lion A-16
- l i bull gt i i glaquo i^_ a ^ bdquo ^ ^
ten from (he Uttattnas lthlaquown in I ijt A fc7 jlaquod deformed lltgt tide of ejch figure fat Location -1h) location A-2raquorgt
^
I
I t - -
BLANK PAGE amp bull
^bull
raquo-raquoMlaquoraquoWr
F)B 472 Sanata tmm lyat 301 itiialf steel fad pin ham Te atfunwed lo (xtmn at 25 C Poriwtt of specimen exposed lo fuel I locatio 4A to location AAIlt) location I6A
~^raquo-raquo i i T -- T-II bullraquoMraquoraquoMr5w mi j immmtmt^m
mm - bull - - bull bull bull - bull -
BLANK PAGE
mdash t - bull bull-bullbull -r^gatMtJliHwJraquoiWrraquovraquotj^WVu^-4-tgt- ~J(W~
fiMAmimraquom0mfMraquo-mdash- --- bullmdashmdash~~^--raquo bull
128
600 iim
M type 904 minim Heel fad pin from TlaquoClaquoM-I Rings taken from the locations shown in Fig 667 and C Portion of specimen exposed to fuel salt is on the lower side of each figure ltn Location 2A Ih) (lt) location I6A
2 ^ - m TMinfc
BLANK PAGE
128
600 pm
Ac locations shown in Fraquo 667 and bullf each fifiire It) Location 1A (ft) 3 L +ot nMtmgwmm
129
rlaquoJ3 raquo T e i bull Tea
nmHtrntMiaoam location
Type Concentration of bull T e C o ~ e ~ r t - o f bull bull T e nmHtrntMiaoam location
Type
bullpm total at JpnWg gcnr at i f f bull p a i o t a l o t a p a V l an or i a f
No 1 - IncondtOI 11 111
A B
S 2 J X 1 0 4tS X 10
4 2J7X 10
poundraquoSx 10 237 x 10
4 444 X 10
IB2 IB2 IB2
A B C
lt2J x 10 159 x 19 7laquoS X 10
4 r7SX 10 114 X 10
lt2J7 x 10 bull00 X 10 744 X 10
4 113 x 10- 45 x 10
IB3 IB3 IB3
A B C
pound53 x 10 27 X 10 247 x 10
4 345 X Iff 331 X 1 0
lt l 7x 10 34 X 10 143 X 10
4 57 X 10 99 x 10
No 2 - HasteHoy N 2raquo1 211
A B
lt M ( 10 749 X 10
4 3-Mx 10bull
lt I 4 4 X 10 497 X 10
4 094 X 10
2B2 2B2 2B2
A B C
raquoj x 10 29S X 10 7t X 10
4 Ml x 10 bull 5 i x 10
lt5 4x 10 202 X 10 594 X 10
4 3-7 X 10 24 x 10
2B3 13 2B3
A B C
lt54 X 10 laquol9x 10 34SX 10
4 422 x 10 bull 249 X 10 bull
lt 5 4 x 10 bull 05 X 10 393 X 10
4 U l x 10 141 x 10-
No 3 type 30 stainless start
3BI 3BI
A B
552 X 10 131 X 10
304 X 10 072 x 10bull
959 x 10 143 X 10
IS0X 10 3-44 x 10
3B2 3B2 3B2
A B C
954 X 10 25copy x 10 900 x 10
bull29 X 10
131 x 10
30 x 10 340 x 10
1042 x 10
bull J l x W iat x io 4laquoX 10
3B3 3B3 3B3
A B C
I M x 10 127 X 10 S3S x 10
116 x Icopy 044 x 10 74 X 10 bull
542 X 10 315 x 10 323 x 10
3-3 X 10 19 X 10bull 197 X 10
A denotes 100 a n aarntwn obuiotd by leaching the metal nanjlr m mbocit (soJimdash Tersenate boric an mdash I iiiinmdash cttnlel B i 100 cm sowlion obtained by l u i l raquo n the metal amftt m raquoraquobullraquo reeja lo remore aboat I M i of nartaLC denotes 100 cm sotation obtained by distorting aboal I g of salt in Mtric icid ( I JO saturated with bone acid Counts for iniiiidojl Radioes gram in dionfegralions pei Minnie (dpntt total for chemistry types A and Band dpM per graa of salt for type C daroMBry saMpfc These cooam ace laboratory w n t u i and abject to sctta corrections omkh lane not been none cThese concentrations are espitjatd as grams of the particnlar nncMr per CM of Metal sartace for cheaaatry ample types A an B ant ar exams of nailidc per gram of alt for chemistry siMpli type C The nines hare been court nd back to the conrfcjsiBn of die H amnion Concentration flwinglit safTiciently low to be ignore
sample numbers ending with I (ie I B l 2B1 and 3BI ) designate the material that came from the fuel pin wall exposed to the gas space above the salt The ample numbers ending with 2 designate material that came from the fuel pin exposed to the fuel salt just below the sail-gas interface and the sample numbers ending with 3 designate material that came from the portion of the fuel pin exposed to fuel salt near the bottom of the capsule Solutions were prepared for analysis by leachshying metal samples of each tube in verbocit to remove residual salt (type A solution in Table 623) leaching the rings in aqua regia (type B solution in Table 623) and dissolving about I g of salt removed from the metal rings in nitric acid (type C solution in Table 623) These solutions were counted to determine the amounts of J 7 T c and T e present The direct results of
these analyses are presented in Table 623 but cannot be interpreted directly because a number of corrections have not been made The data have been corrected as well as possible o reflect the concentration of each nuclide at the end of irradiation The concentrations for the leaches from the metal specimens are expressed as grams per square centinpoundtcr of tube wall exposed to the fuel salt and the concentrations for the salt samples are expressed as grams per gram of salt
The ORIGEN code was used by Kerr and Allen to predict the concentrations of tellurium isotopes that should have been present These calculations have been used extensively in the subsequent analysis of the data Table 624 compares the quantities of 7 raquo T e and l l laquo m T e f o o n ( j m | h e ( n r e e f ^ i p j p W j ( n thoje p r e
dieted to be present by the ORIGEN calculations For
130
each fud pin the one sample taken of the tube in the gas space was assumed to be typical of that region and the two samples from the salt-cowered parts were avershyaged to obtain a typical value for the salt-covered region As shown in Table 6 2 4 generally about 20 of the T T e and 1 T e was found The percent of tellurium found in the Incond 601 capsule was apprecishyably higher due to the higher amount found on the salt-covered metal surfaces
There are several possible ex|)lanations why the conshycentrations of I 7 T e and 2 T e found are only about 20 of those produced One possibility is that the amounts calculated arc too high This appears not to be the case but the calculations wiQ be checked further The most likely explanation is that the add leach was not sufficient to remove all of the tellurium from the wall The tube segments were suspended in the acid with the made and outside surfaces of the tube wall exposed as well as the cut surfacr on each side of the ampin tube segment Based on the weight changes obshyserved and the assumption of uniform metal removal the thickness of metal removed appears to be about 08 mil Since the cracks extended deeper than 08 mil in the HasteDoy N the tellurium likely penetrated deeper than did the leaching solution However the cracks in the other two materials were very shallow and the
08-roii dissolution should have recovered a higher fracshytion of the teflurium if one can equate the depth of cracking to the depth of tellurium penetration The results in Table 6 2 4 show no evidence of a systematic variation in the percent recovered from the three tubes Several possible explanations for the apparent discrepshyancy in the quantities of teflurium generated and that actually found are being investigated but none appears reasonable at this time
The concentrations of 2 7 T e and 2Te found in the salt can be used to predict upper limits for the solubility of tellurium in fuel salt under these condishytions The I 7 Te nuclide concentration in the a l t ranges from 114 X 10 to 131 X 10 g pet gram of salt (Table 623) The ORIGEN calculations were used to estimate the ratio of l 2 T Te to total tellurium and this ratio was used to convert the above concentrations of T T e to total teflurium concentrations of 007 to 083 pom Smiariy the concentration of 2 T e ranged from 45 X 10 to 648 X 10~ g per gram of salt and these correspond to total teluriurn concentrashytions of OJOS to 113 ppm The low values in both cases were noted in the Inconel 601 pin and the higher values were observed in the type 304 stamhts steel pin The concentrations m the HasteSoy N pin were only slightly less than noted for the type 304 stainless steel pin The
TaMt624 A w o mdash l o f T CnhnsM bull n r i o t i kKSfuOtv ol fed pint tmm TcGea-I (a)
IncondoOl HastdloyN Type 304
mje bull T bull gtraquorT e T e mje bull T bull gtraquorT e T e bull T e bull T e
Salt 41 x 10 bull 13 x 10 - 10 x 10- 35 x 10 M X 10 74 x 10 Metal-vapor space 14 x 10 24 x 0 21 X 10 50 x 10 2Jgt X 10 i2 x ie- Metal-sll covet at 17 x 10 23 x I t r 78 x 1 0 25 x 1 3 44 X iW 39 x 10 T
Total fomd 19 X ltgt-bull 27 x IC II x 10-bull 3 5 x 10 laquo 2 x 10 23 X 10 Total formed 3 A 2 x 10 bull 134 x I 0 f 40 x 10 148 x 10 36 X 1 0 134 x 10 laquo ferccM found $2 20 2raquo 23 23 17
of frnl MM hum TlaquoGcn-l (10 aon)
Location Incoiwi bull 1 HastcftorN Type 304
is sled Location bull T e raquo T laquo T e bull T e
Type
bull T e raquo T laquo T e bull T e T e T
Mctal-vapor space Bl MetaMaii location B2 Metal-salt locaiion 83 Avenge if foul yield evenrr distributed
257 bull 75 345
112
446 113 576
413
3J6 152 422
123
94 376
IS 1 456
376 229 095
112
214 I M 103
413
131
higher chromium concentration of the Inconet 60 may have caiced the lower tellurium concentration in the fuel salt
The con-entrations of l l l m J e and t 2 9 m l e are expressed in Table 625 in terms of grams per unit surshyface area There appear to be significant variations within each capsule but there is no consistency beshytween the various pins The high value for ITe in the vapor space of the type 304 stainless steel pin is likely anomalous since the n T e t$ not i s high Thus ai this time we conclude that the tellurium is distributed uniformly over the entire surface area of the pin
616 SALT PREPARATION AND FUEL PIN FILLING FOR TeGea-2 AND -3
M R Bennett A D Kelmers
The purpose of this portion of the TeGen activity is to prepare purified MSRE-type fuel salt containing bulliiV and to then transfer a known quantity of this salt into fuel pins gtr subsequent irradiation in the ORR One batch of purified salt will be prepared and used in two filling operations to fill two sets of six fuel pins each identified as TeGen-2 and TeGen-3 Similar activishyties in 1972 to fill the fuel pins used in experiment TeGen-I have been previously described2 3 To MSRE-
type fuei carrier salt containing LiF-BeF-ZrF4
(647-301-52 moleltv)sufficient U O j and 2 U F 4
were added to produce a fmji composition of LiF-BeF -Z r F 4 - I 3 3 U F 4 - 2 U F 4 63J08-29J5-5 O7-1 0O-15O mole ) after hydefluorination to reduce the oxide content The uranium will be reduced by hydrogen or bv beryllium if necessary to a U3 content of 10 to 18 and a measured xlume of salt will be transferred into the fuel pins The design permits obtaining a preshydetermined volume in the pins by flushing through an excess salt volume and then blowing back the salt in the upper portion of the pins to leave a predetermined volshyume
The equipment in Building 4508 used previously for this work was reactivated and modified where approprishyate A safety summary and step-by-step operating proceshydure have been prepared and approved During the latshyter part of this i port period the salt components were charged to the salt purification vessel and a 364ir hydrofluorination at 600degC was completed Both filshytered and unfiltered samples were obtained after hydroshyfluorination in copper filter sticks After analytical results indicating satisfactory removal of oxide liave been received hydrogen reduction of about 1 of the UF 4 will be carried out
23 R L Sain J H Suffer H E McCoy and P N HjabcnrcKh MSR htrprnm Srmmcvni trofr Rep Aug il 1972 ORNL-4832 pp 90 9
7 Fuel Processing Materials Development
J R DiStefano H E McCoy
The processes that are being developed for isolation of protactinium and removal of fission products from molten-salt breeder reactors require materials that are corrosion restrtint to bismuth-lithium ind inoiiev fluoshyride solutions Past experience has indicated that alshythough their solubiities in bismuth are low iron-base alloys mass transfer rapidly in bismuth at 500 to 700 SC The most promising materials for salt processing are molybdenum Ta-10^ W and graphite Molybdenum has been tested in a wide range of bismuth-lithium solushytions for up to lOjOOO hr and has shown excellent comshypatibility Thermodynamic data and literature reports indicate that molybdenum will also be compatible with molten fluoride mixtures
Ta-10 W also has excellent compatibility with bismuth-lithium solutions but tests are required to measure its compatibuity with molten fluoride salts A thermal convection loop has been constructed of Ta-10 W and a test with LiFBeF2-ThF4-UFlaquo (72-16-117-03 mole ) wffl be started during the next reporting period
Graphite has shown excellent compatibility with both bismuth-lithium solutions and molten salts Although no cheruicai interaction between bismuth-lifcisas solushytions and graphite has been found the hqtsd-KjsuS solushytion tends to penetrate the optn porosity of graphite Recent tests have evaluated the extent of penetration as a function of structure of the graphite and the Uthium concentration of the bismuth-hthium solution Dynamic tests of graphite with bomuth-tithium have thus far been limited to quartz oop tests circulating K - 0 J 0 I wt ( 0 3 at ) Li During the report period a test was
completed in which graphite samples were exposed to Bi-24 w 1 (42 at vt) Li in a molybdenum thermal convection loop for 3000 hr at 600 to 700degC
71 STATIC CAPSULE TESTS OF CRAPHTTE WITH BISMUTH AND
MSMUTH4JTHIIJMSOIIJ110NS
J R DiStefano
Samples of graphite with varying densities and pore diameters were exposed to H-017 wt (48 at ) Li and K - 3 w t (48 at ) Li in capsule tests for 3000 hr at 650degC Two of the graphites (Table 71) were pitch impregnated t j increase their densities and reduce their pore sizes1 The relatively high densities of these graphshyites indicate that impregnation was effective but the pore size distribution in the samples shows that some of the larger pores were unfilled or only partially fdkd Specimens were graphite rods 6 mm (024 in) X 381 mm (15 in) long that were threaded into an ATJ graphite holder The specimens and holder fit into a graphite capsule which contained the bismuth-lithium solution (Fig 7IK The laquoniire aoembiy was sealed in a suhwVss steel outer capsule by welding in argon Samshyples exposed to 61-017 wt (48 at ) Li showed little evidence of penetration except in low-density areas (Fig 12) Samples exposed to Bi-3 wt (48 at ) Li were penetrated more uniformly and the depth
1 Al grapfcilei were fabricated by C ft Kennedy of the Carbon and Graphite Groap Merab and Ceramics Dmnon OftNL
TaMr7l P f t trjtnPnt 01 yinpfcitt fcy lNpMvtfc4ilfcM McapfritttattlbrJtei b r a t t s r c
MISflMM
Graphite demtty Igcml
Ranee of porediam
Maximmn pore diameter chat
conrribnies 10 to total pDtoaly
ltraquogt
nuefration (mils) bulldentiOcatiow
demtty Igcml
Ranee of porediam
Maximmn pore diameter chat
conrribnies 10 to total pDtoaly
ltraquogt K 0ITOU m 3Li
334K 44-25 K 33-3SK 44-26K 44-23K
IM IM 190 ISO 159
01 1 01 2 01 2 01 35 OI 4 5
1 12 I J I J 45
0 5 0 17 8 0 5 5 0 -2 8 0 2 15
Impregnated
NonvMrform penetration in one -gtr two area only
132
133
0MlaquoL-0laquoCrS-l4M9
Flaquo 71 GapMe (bimdasheh lithww) opiate fed asmMy
of penetration increased with increasing pore size and decreasing density Results from previous tests have been inconclusive as to tnr effect of lithium concentrashytion in bismuth on penetration of graphite In the curshyrent series all graphites were penetrated tc a greater extent by K - 3 wt (48 at ) Li than by Bimdash017 wt 9f (48 at ) Li Tests of 10000 hr duration with these graphites are continuing
72 THERMAL GRADIENT MASS TRANSFER TEST OF GRAPHITE IN A MOLYBDENUM LOOP
J R DiSuiano
Although graphite has low solubility in pure bismuth (less than I ppm at 600degC) capsule lest results have shown that higher carbon concentrations are present in Bi -2 wt (38 at ) Li and K-3 wt (48 at ) Li solutions after contact with graphite To avoid the joining proolems associated with fabrication of a graphshyite loop a molybdenum loop was constructed and interlocking tabular giaphite specimens were suspended
in the vertical hot- and cold-leg sections2 In addition to mass transfer of graphite from hot- to cold-leg areas penetration of graphite by bismuth-lithium and mass transfer between graphite and molybdenum were evalushyated
721 WcajMCkaafes
The loop (CPML4) circulated K-24 wt (4 at 3 ) Li for 3000 hr at 700degC (approximately) maximum temperature and 600degC minimum temperature Weight changes in the graphite samples are given in Tables 72 and 7 J After the bismuth-lithium solution was drained from the loop the samples were removed and weighed (after-test column in Tables 12 and 7 3 ) Subshysequently they were clltmdashned at room temperature in ethyi alcohol and in an hO-HNOj (100 ml H 2 O-30 ml 90 HNOj) solution to remove bismuth-lithium adhering to the surfaces of some samples Samples from the cold leg were weighed and then kept in air for two days prior to the alcohol treatment After soaking in alcohol these samples showed larger weight gains than the after-test weight gains and this is attributed to reacshytion of lithium in the sample with moisture in the air during the two-day period AD samples showed large weight gains (33-67) and gains in hot-leg samples were on the average larger than those in the cold-leg samples
122 Compositional Changes
Graphite samples were analyzed before and after treatment with H 2 0 - H N 0 3 and the results are shown in Table 74 These results indicate that bismuth was primarily responsible for the large weight increases and that samples picked up molybdenum but treating them with H 2 0-HNOj completely removed the molybshydenum An electron-beam microprobe analysis of a graphite sample before acid cleaning showed that molybdenum was present on the outer surface of the specimen (Fig 13) Chemical analyses of other graphite samples after acid cleaning are shown in Table 75
Analysts of bismuth-lithium samples from the loop are shown in Table 76 For sampling the hot leg was sectioned so that one sample came from the surface that was in contact with the molybdenum tube wall while the other sample was taken from the interior of the section away from the wall The concentration of carbon in the melt was highest in the sample from the hot leg and both molybdenum ami carbon concentra-
2 i R DiStefano MSR Program Semimnu frofr Rep Pth 28 1975 ORNL-5047pp 140 41
li-3 11 V-IMIOi
-I5H raquobull Mplaquolaquom
F| ) NtMlnltpnorpirMttuiriMwManorMnKluHurinfMltiiid Itlhlum InMwiulli tuniliiiltgtnraquo IIHNI hr M fcjnV
13S
r7J iraquoATJ bull CML4
Wclaquofci If) Welaquofci bullKVU9 I
n mdash t r i bullefore Mi l
After m i
After
bull U k n t w l
After
raquoH04mo
Welaquofci bullKVU9 I bullefore
Mi l After m i
After
bull U k n t w l
After
raquoH04mo ltlaquo) laquoltgt
5 0 4 5 3 0S244 0 1 2 2 0704 02443 54 7 05220 0970 0 95 0S29S 0 3071 59 04494 09551 0933 0X298 OJ304 6
| l gt 0 400 0959 0919 07944 03144 I I 0432 0 3 3 9 0S3O3 07102 0277 4 12 0 4 5 09302 0923 079 03075 7 13 04753 0979 0974 0 7 02933 2 1 0432 09175 09152 075 0302 5 17 04742 09099 0905S 0794 02952 62 IS CS070 09005 0 J 9 5 07975 0290S 57 1 04709 0-raquollaquo9 0142 0 7 1 02459 52 zo 0539 091 M 09149 0 107 0 J 7 J 51 21 0513 OK52 0 J 2 9 072 02453 4 22 0 5 I M 0 M99 0 M59 0759 0J407 4 23 0-539 09103 090 07475 02067 3 24 03405 0 5 4 5 0 4 9 7 07235 01130 33
Top of IKM ley I
Kwlion of hoi leg M laquo | I J M I
rare 0 700C Q0-2OC
Vclaquofti it)
Wclaquoht After Wclaquoht
n m b r t Before After stjfldiHC in am tot two day
After
H 0 -HNO
mcreaK n m b r t
lev lejl
stjfldiHC in am tot two day
After
H 0 -HNO ltIgt I
makohol
27 04 4 0749 0722 0 4 0 01794 39 2 0421 0 2 4 OS4I2 0 2 0 01439 30 29 04717 07793 07913 06433 0 I 7 - 36 30 0477 0713 07239 0291 0151$ 32 31 044 07209 07315 0 3 9 a i 5 4 8 32 32 0427 0729 07744 0647 01 raquo20 3 33 047ft 07193 07 TOO 0331 01543 32 34 0470 0756 0772 0653 012 39 35 0424 073raquo2 0745 0 2 9 0 016 3 3 0423 0749 0759 0343 01520 32 37 0447 07331 07432 0 239 01572 34 3S 04713 07513 0719 0641 01705 3 39 04745 0749 070 0 506 0171 37 40 042 0725 07390 0233 01605 35 41 04725 0745laquo 07J53 0 419 01694 3 42 04100 07427 07525 0652 01726 36 4 3 0476 0720 07401 0647 01712 3
Top of onM leg lempmlvrc 60 60 C ftotlom of cold ley temperalarc 620 630C
136
aMr 74 n a m e d bull bull bull bull bull bull bull ttVli
S jmr t rm HRJIWT Coadiiion Cuacramnunlraquo i
S jmr t rm HRJIWT Coadiiion 3i Li gt
4 (hH WTraquo 4 tbraquort llaquogt
i Ui4d iclt
l a t k a a r d Acid cftcaAGd (bullctnacd Atid ckaacd
4 3 43 40
bull gt 0J I 04
bull11 ltlaquolOI
bullMM ltlaquoMU
tions were higher than were found previously in quart loop tests circuiting Bi-OjOl wt (03 n bulllt Li Quartz loop test 11 contained molybdenum samples and analysis of the bismuth-Uthium solution after test shewed that t contained 25 ppm molybdenum Quartz loop 8 contained samples of three different grades of graphite and the bismuth-tiimum solution contained 10 to 15 ppm carbon after the test
J O B Caiwt j ad L ft Trotter MSR i Awfr Rep Air _ 1971 OKSL-4 p i - 3
V1330SS
BACKSCATTERED ELECTRONS
- - - Oraquo J
V
8 i M a X-RAYS Me L X-RAYS
Ffcgt 7J EMCWIM kmn) laquoeaaninj M H J M r laquoapnlaquo taawnf to Mnmrth Vnw IA) a backmttcrcd electron picture of sample tarface dark material n tnpfcitc and bright material is bianulh and malybdemHM as indicated by iff)and O
117
Tank 7 3 C k a m anakwaaf p i j i i i r bull bull | l i r f c mdash C F M L - 4
bull bullbe U Mo
1 Hot kg 37 0J5 ltOJraquol ltraquo H o i k s 42 044 lt0OI
15 H o i k 4 04 ltO01 l raquo Hocks 3 0 J 5 lt 0 0 1 24 Hotks 2i 025 ltOOI ^ T C o M k f J 0 3 5 ltO0 I 31 C o M k f 21 0 2 5 lt00I 3 C o M k f I t 02 ltoot 42 CoMkc 23 02 lt0Jraquo
Sampio plusmni deaneu m H OMNO prior to a i r
Tabk7 A ^ s t t t a M M i
CoaceaiDiMt
Sample location C ippa l
Mo tppau
Li fit
Hot k f icowl Kof kg iflwfaotf r
CoM kg loner
43 10 24
17 102
4
23 3 0 1
On a raghl bam Interior tampk
Surface simple in contact raquonb molyb i fcmdash rabe laquoaH
Selected graphite samples from hot- and cold-leg regions are shown in fig 74 The white phase distribshyuted throughout the samples is bismuth these samples were add cleaned and it is evident that bismuth was dissolved from the area near the surface Molybdenum samples from hot- and cold-leg regions are shown in Fig 75 Surface layers measuring 0015 to OJ025 mm (0 6 -1 mil) thick were found on the hot-kg sample In some areas ttwie was a single layer while a double layer was found in other areas Electron-beam mkroprobe analysis indicated the single layer andor outer layer to be primarily molybdenum This layer was much harder than the base metal (1000-1200 DPH compared with about 200 DPH) indicating that it is probably MojC Where there is a double layer the outer layer appears to be MojC but the inner byer n primarily bismuth One explanation is that the MojC layer cracked andor spailed allowing the entry of bismuth which did not drain when (he lest was terminated The molybdenum sample from the cold leg also exhibited a surface layer
i o raquo f l u C mm t h k k i gt i i 33S SSSH3 S CCSSpSKBOS to that found in the hot leg Samplrs of molybdenum from hot and cold legs have been submitted for chemishycal analysis
The prindtMl objective of this experiment was toeval-uate temperaiure-gtadieai mass transfer of graphite in bismuth umijiuiug a retainer high concentration of lithium However mass transfer data were obscured by the gross pickup of bismuth by the graphite samples Previous capsule and quartz loop tests with ATJ graphshyite had indicated much less intrusion of the graphite by bismuth than occurred in the molybdenum loop test This suggests that the permeabihty at ATJ graphite to bisnush-hdnum does not depend simply on the po-rc^y of the graphite It is generally accepted that some fracioa of the pores in graphite is effectively sealed off 7uraquo contributes nothmg to flow Therefore the conshynected pore system controls the penneabraty The shape of the connected pores influences the type of flow and die length of the path the fluid takes through the sample For a nonwettiug liquid the external presshysure forcing the liquid into the pores 1 must overshycome the surface tension of the liquid This defines a critical pore radius r( and unt l the pressure exceeds the value given by
lrraquo=27costfr c ltgt
where y is the surface tension and 9 the wetting angle the pore cannot support flow Thus for a given - I f rc is the minimum pore size that w H be penetrated In both the metal and quartz thermal convectica loops IT is determined by the argon overpressure ( lt l atm) and the height of btsmmh-fcthium solution above the sample and these wne essentially the same in both types of tests Temperature affects both a and 9 but all o( the tests were operated under similar thne-temperature-^r conditions Graphite samples used hi the quartz too tests had almost four limes the surface area o f the tabushylar specimens used in the current test but they were almost three times as thick The larger surface area of the quartz loop specimens should have increased the relative amount of bismuth-lithium intrusion but the greater thickness of these samples would reduce the pershycentage increase ATJ graphite samples from the quartz loop tests increased in weight by 01 to 06 wt ar far less than the 30 to 67 wt increases noted hi samples from the current loop test Thus specimen geometry alone does not seem to explain the differences noted However the surface tension o and wetting angle 9 were
138
3
i 8
a
139
Y-I33405
- n r fimfir nriiiTii ifiari Bottom of Hot Leg 600C Bottom of Cold Log 620C
f 75 MolyMniBin tube waN from thermal comectkm loop CPML-4 thai cin slated Bi-24raquo Li and contahnd graphite ^CCMCHS
probably different because the lithium concentrations of the bismuth-lithium solutions were different and molybdenum was present in the current test It is posshysible that the presence of molybdenum on tie surface of the graphite had a marked effect on the contact angle 0 fn an earlier series of tests the bismuth content of graphite specimens was much higher when they were tested in molybdenum capsules instead of graphite capshy
sules4 Accordingly data on the wetting of graphite by-bismuth containing lithium and other constituents of processing solutions would be useful for predicting the resistance of graphite to penetration
4 J R PiStefano and O B CavmMSR Profnm Semumnu Pmgr Rep Feb 2K 1975 ORNL-SM7 pp 137 39
Pan 4 Fuel Processing for Molten-Salt Reactors
J R HightowerJr
The activities described in this section deal with the development of processes for the isolation of protacshytinium and for the removal of fission products from molten-salt breeder reactors Continuous removal of these materials is necessary for molten-salt reactors to operate as high-performance breeders During this report period engineering development progressed on continuous fluorinators for uranium removal the metal transfer process for rare-earth removal the fuel recon-stitution step and molten salt-bismuth contactors to be used in reductive extraction processes Work on chemistry of fluorination and fuel reconstitution was deferred to provide experienced personnel for the prepshyaration of salt for the TeGen-2 and -3 experiments (Sect 617)
The metal transfer experiment MTE-3B was started In this experiment all parts of the metal transfer process for rare-earth removal are demonstrated using salt flow rates which are about 1 of those required to process the fuel salt in a lOOO-MW(e) MSBR This experiment repeats a previous one (MTE-3) to determine the reasons for the unexpectedly low mass transfer coeffishycients seen in MTE-3 During this report period the salt and bismuth phases were transferred to the experishymental vessels and two runs with agitator speeds of 5 rps were made to measure the rate of transfer of neo-dymium from the fluoride salt to the Bi-Li stripper solushytion However in these runs the fluoride salt was enshytrained at low rates into the LiCl which resulted in depletion of the lithium from the Bi-Li solution in the stripper Fuel-salt entrainnient was unexpected since no entrainment was seeii in experiment MTE-3 under (as far as can be determined) identical conditions The Measurement of mass transfer coefficient in these first tvo runs was not compromised by the cntrainment The measured mass transfer coefficients were lower than
predicted by literature correlations but the values are comparable to those obtained from experiment MTE-3
Mechanically agitated nondispersing salt-metal conshytactors of the type used in experiment MTE-3B are of interest because entrainment of bismuth into the fuel salt can be minimized because very high ratios of bisshymuth flow rate to salt flow rate can be more easily handled than in column-type contactors and beczuse these contactors appear to be more easily fabricated from molybdenum and graphite components than are column-type contactors Attempts were made to measshyure entrainment rates of fluoride salt in bismuth and entrainment rates of bismuth in fluoride salt under conshyditions where the phases were not dispersed and under conditions where some phase dispersal was expected These measurements were made in the o-tn-diam (01 S-m) contactor installed in the Salt-Bismuth Flow-through Facility The results indicate that mild phase dispersal with in concomitant high mass transfer coeffishycients night be allowable in the reductive extraction processes We are continuing development of methods for measuring mass transfer coefficients in mercury-water systems to learn how to scale up contactors which would be used with salt and bismuth
A nonradioactive demonstration of frozen salt corshyrosion protection ir a continuous fluorinator requires a heat source that is not subject to attack by fluorine in the fluorinator To provide such a heat source for future fluorinator experiments we have continued our studies of autoresistance heating of molten salt During the report period we have completed new equipment for studying autoresistance heating of molten salt in a flow system similar to a planned continuous fluorinator exshyperiment three preliminary runs have been made with the equipment The design was started for a facility for developing continuous fluorinators and equipment is
140
141
being installed for an experiment to demonstrate the effectiveness of frozen salt for protection against fluoshyrine corrosion
The uranium removed from the fuel salt rraquogt fiuorina-tion must be returned to the processed salt in the fuel reconstitution step before the fuel salt is returned to the reactor An engineering experiment to demonstrate the fuel reconstitution step is being installed In this experishyment gold-lined equipment will be used to avoid introshyducing products of corrosion by U F and U F S Alternashytive methods for providing the gold lining include elecshytroplating and mechanical fabrication The choice beshytween the two depends on availability of gold from fcRDA precious-metal accounts and the price of gold from the open market Instrumentation for the analysis
of the vessel off-gas streams has been installed and is being calibrated
Future development of the fuel processing operations wdl require a large facility for engineering experiment A design report is being prepared to define the scope estimated design and construction costs method of accomplishment and schedules for a proposed MSBR Fuel Processing Engineering Center The building will provide space fcr preparation and purification at salt mixtures fcr engineering experimenis up 10 the scale required fcr a I0OO-MW(e) MSBR and for laboratories maintenance areas and offices The estimated cost of thrs facility is SISjOOOjQOO and authorization is proshyposed for FY 1978
R Engineering Development of Processing Operations
J R Miditower Jr
81 METAL TRANSFER PROCESS DEVELOPMENT
HC Savage
During this report period the salt and bismuth solushytions were charged to the process vessels of the metal transfer experiment MTE-3B Two experiments were completed in which the rate of removal of neodymium from molten-salt breeder reactor fuel salt (72-16-12 mole LiF-BeF 2-ThF 4) was measured
The MTE-3B process equipment (Fig 81) consisted of three interconnected vessels a 14-in-diam (036-m) fuel salt reservoir a 10-in-diam(025-m)salt-metal conshytactor and a 6-in-diam (015-m) rare-earth stripper The salt-metal contactor is divided into two compartshyments interconnected through two 05-in-high lt 13-mm)
I H C Savage Bngmeenng Development Studies for Molten-Sat Breeder Reactor Processing Xo -0 ORNL-TSM870 (in preparation)
by 3-in-wide (76-mm) slots in the bottom of the divider Bismuth containing thorium and lithium is cirshyculated through the dots Thus fluoride fuel salt was in contact with the Bi-Th in one compartment and LiG was in contact with the Bi-Th in the other compartshyment The stripper contains lithium-bismuth solution (5-95 at ) in contact with the LiCl Mechanical agitashytors having separate blades in each phase in the conshytactor and stripper were used to promote mass transfer across the three salt-metal interfaces The fluoride fuel salt was circulated between the reservoir and contactor by means of a gas-operated pump with bismuth check valves The LrCl was circulated between the stripper and contactor by alternately pressurizing and venting the stripper vessel
The bismuth-thorium phase was circulated between the two compartments of the contactor by the action of the agitators and no direct measurement of this flow rate was made during the experiment however measshyurements made in a mockup using a mercury-water system indicated that the Bi-Th circulation rate between
ORWL-06-71 1471
AWTATORS-
LEVEL ELECTRODES
LiT-raquoF--TMU Li-a
FLUORIDE SALT
RESERVOIR
SALT- KCTAL CONTACTOR
M M EARTH STRIPPER
F 81 Flow diagram for metal trmrfcr experiment MTC-3
142
143
the two compartments should be high enough to keep the concentration of rare earths in both compartments essentially the same2 This was found to be the case in the two experiments in MTE-3B
In this experiment neodymium is extracted from the fuel carrier salt into the thorium-bismuth solution Next the neodymivm is extracted from the thorium-bismuth into molten LiCI and finally (he neodymium is stripped from the LiCI into bismuth-lithium alloy
Operating variables in the experiment are
1 the flow rate of the fluoride fuel salt between the fuel salt reservoir and the contactor
2 the flow rate of the lithium chloride salt between the contactor and the stripper vessel
3 the degree of agitation of the salt and bismuth pluses in the contactor and stripper
4 the amount of reductant (lithium) in the bismuth phase in the contactor
The operating temperature of the systen is ^-650degC Overall mass transfer rates for representative rare-earth fission products are determined by adding the rare earth to the fluoride fuel salt in the reservoir and observing the rate of transfer of the rare earth across the three salt-bismuth interfaces as a function of time by periodic sampling of all phases
2 H O Weeren and L E McNcese Engineering Developshyment Studies far Molten-Sail Breeder Reactor Processing So 10 ORNL-TM-3352 (September 1974) pp 57 59
[taring the course cf the experiments the concentrashytions of neodymium in each phase were deteiiaiacd by counting the 053-MeV gamma radiation emitted bv 4 T N d tracer added to the neodymium origmaBy in the fuel salt This provided a rapid method for fallowing the transfer rate More accurate data necessary for calculatshying the overal mass transfer coeffiaeats at each of the three salt-metal interfaces were obtained by analyzing samples of the salt aM bismum phases for total teo-dymium via an isotonic dilution mass spectrometry technique Use of this technique avows measurement of neodymium concentrations as low as OJOI ppm (wt)
811 of Salt J to Metal MTF3
The quantities ot salts and bismuth charged to the process vessels of experiment MTE-3B are listed in Table 81 AD internal surfaces of the carbon-steel vesshysels were hydrogen treated at 650degC for V7 hr to reshymove any oxides prior to the addition of the salt and bismuth solutions The auxiliary charging vessels used in the additions were also hydrogen treated Subsequently a purified argon atmosphere was maintained in all the vessels to prevent oxide contamination (via ingress of air or moisture) of the vessels and process solutions
The charging vessels were IO-in-diam (0_25-m) carboa-steH vessels o f about 22 liters (0022 m 3 ) in volume equipped with electric heaters for melting the salts and bismuth Nozzles and access ports were pro-
Tabie8l Qwtit iet ot salts and tnsmmtk for o u M i w f t MTE-3B
Material Vessel Volume at
650C (liters)
Wesgh (kg) f-moles
Fluoride fuel salt Reservoir 294 970 5lt (72-16-12 mole LiF-BcF -ThF)
Fluoride fuel salt Contactor 31 102 161 (72-16-12 mole LiF-BeF-ThF)
Bismuth-thorium | M 500 ppm (wt) Th Fluoride salt 29 276 132 MO ppm Li| side of contactor
Bismuth-thorium [M500 ppm (wl)Th LiCI side of 35 33 161 M 0 ppm Li| contactor
Lithium chloride Contactor 29 43 101
Lithium chloride Stripper 38 56 132
Bismuih 5 at lithium in Stripper 43 418 200 stripper
Demiliev at 650C fluoride fuel salt 330 gcc LiCI = 1 AS gcc Bi 96 gcc Mole weight = 632 g
144
video for the addition of the salts and bismuth argon and hydrogen purge gas ones and hues required to transfer the salt and bismuth phases into the process vessels
Bismuth hydrogen treated in the charging vessel to remove oxides was the first material to be added to the contactor The fluoride fuel salt was then contacted in the charging vessel (using argon sparging) with a bismclaquoi-OIS wt thorium solution (50 of Th satushyration) for several days prior to transfer into the fuel-salt reservoir and the fluoride salt compartment of the contactor Thorium metal (01197 kg) was then added to the 614 kg of bismuth in the contactor This quanshytity of dtorium is about 50 of the amount that would be soluble and was calculated to produce a lithium conshycentration ot ^-40 ppm (wt) in the thorium-bismuth phase in the contactor based on previously reported data1 on the distribution of thorium and lithium beshytween molten bismuth and fluoride fuel -alt
FoBowing the additions of bismuth to the contactor and the fluoride fuel salt (72-16-12 mole LiF-BeF2-ThF 4) to the contactor and fuel-salt reservoir a new charging vessel was installed for makeup and charging of the bismuth-5 at lithium to the stripper and the LiCI to the contactor and stripper First bismuth was added to the charging vessel and was hydrogen treated to remove oxides by sparging with hydrogen at v-oOOC (873degK) for laquoraquo7 hr The charging vessel contained 6787 kg of bismuth to which was added 0120 kg of lithium metal to produce the bismuth-5 at lithium for the stripper Part of the bismuth-5 at lithium solution (41 amp kg) was then transferred into the stripper vessel
Thorium metal (0109 kg) was added to the 26 kg of bismuth-lithium solution remaining in the charge vessel and 1588 kg of LiCI that had been oven dried at 200degC (473degK) was added to the charge vessel The bismuth-lithium-thorium and LiCI phases were sparged with argon using a gas-lift sparge tube for four days The LiCI was then transferred into the LiG side of the conshytactor and the stripper vessel
The salt and bismuth solutions were filtered through molybdenum filters [^30 u (30 X I0~ 5 m) in pore diameter] installed in the transfer lines during transfer
- from t^e charging vessels into the MTE-3B process vessels
812 Run Nd-I
For the first run in MTE-3B 3300 mg of NdF (2360 mg of Nd) was added to the 97 kg of fluoride fuel salt (72-16-12 mole LiF-BeF2-ThF4) in the fuel salt resershyvoir on June 6 1975 The neodymium contained 722 mCi of TNd tracer (tVi - 11 days) at the time of
addition The neodymium concentration in the fuel salt in the reservoir was calculated to be 24 ppm (wt) which approximates that expected in the fuel salt of a single-region lOOO-MWie) MSBR Neodymium was chosen as the representative rare-earth fission product for the first series uf experiments in MTE-3B for several reasons
1 results could be compared with those obtained using neodyrahnn in the previous experiment4 MTE-3
2 Sd tracer used for following the rate of transfer of neodymiuni has a relatively short half-life (11 days) which would prevent excessive levels of radioshyactivity in the experimental equipment as additional neodymium containing 4 7 N d was added to the fuel salt during the expert-went
3 neodymium is one of the more important trivaknt rare-earth fission products to be removed from MSBR fuel salt
An attempt was made to start the first run (Nd-I )on June 91975 However a malfunction in the electronics of the speed control unit for the stripper-vessel agitator prevented startup After this unit was repaired run Nd-1 was started on June 15 1975 and the scheduled period of operation (100 hr) was completed on June 20 1975 Operating conditions of run Nd-I were 650 to 660CC (923 to 933degK) 5 rps agitator speeds in both contactor and stripper fluoride salt flow rate of 35 ccmin (58 X I 0 1 m 3sec) and LiCI flow rate of 12 litersmin (20 X IO 5 nrsec)
After 100 hr of fluoride salt and LiG salt circulation the fluoride salt circulation was stopped and the run was continued for 16 hr This was done to observe the expected large decrease in the concentration of neoshydymium in the smaller amount of fluoride salt in the contactor (102 kg) as compared with the 1072 kg contained in both the contactor and reservoir These data would provide a more accurate measure of the rate of transfer of neodymium across the fluoride salt-bismuth-thorium interface
Finally the circulation of LiG was also stopped The agitators in the contactor and stripper vessels were then operated for ^24 hr over a three-day period (8 hr each day) to allow the salt and bismuth phases to equilibrate in an attempt to determine neodymium distribution coefficients between the phases
3 L M Ferris Equilibrium Distribution of Actinide and Lanthanide Elements Between Molten Fluoride Salts and Liquid Bismuth Solutions Inorg Nucl Chem 32 2019 35 (1970)
4 Cfiem Ttchnol Dir Annu Prop Rep March 31 1973 ORNL-4883p 25
145
The experimental equipment operated safisfacturBy throaghout ran Nd- I AH operatiag variables were maia-taiaed at desired coaonioas Results obtained during run Nd-I are discussed in Sect 814
SI J Ran Nd-2
Run Nd-2 was done with the sam operating condishytions as ran Nd-I except for run deration (119 hr inshystead of 100 hrraquo Prior to run Nd-2 3590 mg of N d F
(250 tog of Ndgt coalaaaag 101 mCi of 4 7 N d tracer was added to the 97 kg of fad salt in the reservoir Including the ncodVaaum leinainaig in the furl salt at the end of ran Nd- I estimated to be 18 ppra ltwt) the neodymium concentration in the fuel salt in the resershyvoir at the start o f run Nd-2 is estimated to be 45 pom The neodynaum concentration in dte fuel salt in the contactor is estimated to be 9 ppm at the start of run Nd-2 We are uncertain of the amounts of neodymium in the other phases at the beginning of run Nd-2 as discussed in Sect 814
Run Nd-2 was started on July 13 1975 and was tershyminated on July 19 1975 after 139 hr of operation During the first 50 hr of operation the rate of transfer of neodymium into the lithium-bismuth phase in the stripper appeared to be about the same as observed during run Nd-I based en counting of the | 4 7 N d tracer in samples taken at regular intervals After about 60 hr of operation the transfer of neodymium into the bismuth-lithium phase in the stripper suddenly stopped and it was observed that neodymium was being exshytracted from the bismuth-lithium phase in the stripper into the LiCl in the stripper and contactor During the run a significant decrease in the emf between the stripshyper vessel and the contactor occurred (from ^160 mV to ^25 mV over a 30-hr period) indicating loss of lithshyium reductant from the bismuth-lithium phase The run was terminated after 139 hr of operation when it beshycame clear that useful information could no longer be obtained and it appeared that fluoride salt was being entrained into the LiCl in the contactor
814 Discussion of Results
Subsequent investigation and results of chemical analshyyses of samples of the salt and bismuth phases indicate that fluoride fuel salt was being entrained into the LiCl in the contactor throughout both runs Nd-I and Nd-2 Estimates of the amount entrained are shown below
Estimated amount of fluoride a l l transferred into LiCl Baas of estimate
Nd-I | I 0 laquo hr) Nd-I and -2 (Jul hr)
0292 kg Fluoride in IiO phase 0607 kg Thorium in B I - L I phase 0400 kg Increase in LKI level in
stripper
Based j a flaoriae analyses of 1X1 maple T taken daring nm Nd- I the enuaaaaeat of flaoride salt appears to have occurred at a relatively constant rate throaghoat the ran The total amount of neodyaaam which transshyferrer into the Li-K phase in the stripper daring ran Nd-I is estimated to be 300 mg The aaaoaat of aeo-dynaam contained in the entraiaed fad salt isestiuated to be 6 mg That most of the neodynaam which transshyferred into the Li-Hi in the stripper vessd was by mass transfer rather than as a result of eatiaauaeM
The reason for the ubstivtd enfaauaeat is not dear at present One explanation K that the 50-rps agitator speed is saffident to cause enirainment (entrainmeat of flaoride salt into the chloride salt occurred in the preshyvious experiment MTE-3 at 67 rps bat not at 5JO rps) Experiments are in piogiess for deternaaing whether this explanation is correct and results to date indicate that entranirmi does not occur at 3 3 rps Further experiments in MTE-3B w i l depend on determining the reason for the unexpected entrainment of fluoride nt into the LiCl- However it appears feasible to continue rare-earth mass transfer experiments in MTE-3B by removing the LiCI (contaminated with fluoride salt) and the Li-Bi solution from the stripper vessd after which purified LiCl and Li-Bi solution will be added to the system
The main nurpose of the metal transfer experiment is to measure mass transfer coefficients for the rare eanhs at the various salt-metal interfaces in the system and to determine whether a literature corrdation5 (based on studies with aqueous-organic systems) which relates many transfer coefficients to the agitator speed and other physical properties of the system is applicable to molten salt bismuth systems Data obtained from run Nd-I have been analyzed and estimates have been made of overall mass transfer coefficients for neodymium at the three salt-metal interfaces Even though entrainment of fluoride salt into LiO occurred during run Nd- I it is believed that the mass transfer rate for neodymium was not 5ignificantly affected The concentration of fluoride in the LiCl at the end of run Nd-I was vl_ wt 1 or 003 mole fraction Based on previous studies6 the disshytribution coefficient ) for neodymium between the molten bismuth-thorium solution and LiCl (mole fracshytion Nd in bismuthmole fraction Nd in LiCl) would be decreased by ^ 2 0 7 while the distribution coefficient for thorium would be decreased by a factor of ^150 This would result in a decrease in the separation factor
5 J B l-ewii Chan En Sri 3 24S 59 119541 6 I M Ferris el raquo Distribution of Lanthamde and
Actinide Klements Between Liquid Bismuth and Molten IKI-Iil- and liBr-lil Solutions Inorg ucl Chart 34 313 20(1972)
146
were t in
VIO to vIO1 i transferred
bull t o the Lid The ate of leaver of neodynuua across the three
byaaslysesofi the m Two analytical i
(1) coasting of the OS34acV by the 4 N i tracer aad (2)iKgttopicduu-
spectroaaetry luaed on ccejufhag of the 4 T N d tracer a aaMeriai buuare of the t w t j i i w of gt95 obtained at the end of run Nd-1 indicated that about 11 of the niudjununa mfrinaMj added to the fuel salt icaenvar had beea transferred iato the LMI irautioa at the stripper
The counting trchaiqf is a rapid method aad pro-oa the rate of transfer wide the mas llwwcui it does ant provide the
required for calculation of the overal mas transfer coefficients particalariy in the K-Th aad Lid
bull the contactor aad stripper vessels in which the less than 1 ppm
(wt) The isotonic ddutioa analysis is capable of accushyrately determining neodynmm conccntntioa down to -VOJOI ppmfwt) and resorts obtained from the isotopic duvtioo tednaque for the Bs-Th and LiCI phases were used for calculations of the overall mass transfer coeffishycients
Values for distribution coefficients for neodymium at the thru salt-metal internees were measured at the end of run Nd-1 for comparison with those calculated from the dau of Ferris3 bull (Table 82) The experimental values are in reasonable agreement with the calculated values in the absence of fluoride contamination indicashy
ting that the distrnVstsoa coefficieau for neodynnum were not seriously affected by the entKnuncnt of the fluorine sah into the chloride
Data obtained during run Nd-1 were analyzed by inuahawiiui solution of seven tune-dependent differenshytial mm rial twlanu equations (Fig 8 J ) that relate the
v i imdash F t laquo r V
raquo i W W F a laquos-X4gt
V j j l laquo bull Klaquoa (X-IVCraquo)-F(Xs-)^
V - MOLAR VOLUME OF EACH PHASE
F bull FLOW RATE MOLESSEC
7 L M Perm et d Distribution of Lanthannte and Actiniae Element Between Molten Uthium Halide Salts and Liquid Msmuth Solutions Inorg Piuci Oirm 342921 -33 lt1972)
OLOLDc RARE-EARTH DISTRIBUTION COEFFICIENTS MOLESMOLE
A AREA AT EACH INTERFACE CM
TaMrSJ Dutrwatioa coeffionrta for mod m msit iauat MTE-3B ran Nd-1
Salt-metal interface Calculated Experimental
Fluoride salt-Bi-Th LaO-Bi-Th LiQ-Li-Bi
0006 094
3-5 X 10
0013 064
gt I X I0raquo
Distribution coefficient laquo (mf Nd in bismuth)(mf Nd in salt) ^Conditions 6S0C (923degK) Li concentration in Bi-Th 40 ppm Li concentration in Li-Bi = 5 at no fluoride in LiG phase
K I KbdquoK gt RARE- EARTH OVERALL MASS TRANSFER COEFFICIENT CMSEC
X gt RARE- EARTH CONCENTRATION IN EACH PHASE MOLESCM
EQUATIONS USEO TO CALCULATE MASS TRANSFER COEFFICIENTS FOR METAL TRANSFER EXPERIMENT
MTE-3B
F raquo S X Equations awd to calculate maw traaafer coeffishycients for the metal Mifer p r a m experiment V volume of each phase x - rare-earth concentration l = lime A - mass transfer area F raquo flow rate D bull rare-earth distribution coeffishycient K = overall mass transfer coefficient
147
rate at which the rare earths r ~ transferred through the several stages to the distribution coefficients of the tare earth the mass flow rates and the mass transfer coeffishycients at each salt-metal interface The set of equations was solved using a computer program by selecting values for the mass transfer coefficients which resulted in the best agreement between the experimental data on rate of change of neodymium concentration in aB phases in the system and the calculated values Several trial-and-error iterations were required using adjusted values of mus transfer coefficients until a best-fit solution was obtained
The final calculated results for run Nd-1 are shown in Table 83 where the values for the overall mass tkjnsfer coefficients are given and are compared with values calshyculated by the correlation of Lewis5 The coefficients are lower than predicted and are similar to results obtained in the previous experiment MTE-34 Final analytical results for run Nd-2 are not yet available However for the first SO hr of operation the rate of accumulation of neodymium in the Li-Bi solution in the stripper appeared to be similar to that observed in run Nd-1 The significance of these absolute values of mass transfer coefficient cannot be assessed until the scaling laws in this type of contactor are known
8 L E McNeeje Engineering Development Studies )or Molten-Salt Breeder Reactor Processing o II ORNL-TM-3774 (in preparation)
8 2 SALT-MSMUTH CONTACTOR DEVELOTMENT
CH Brown Jr
Mechanically agitated nondispening salt-bismuth conshytactors are being considered for the protactinium removal step and the rare-earth removal step in the reference MSBR processing plant flowsheet These conshytactors have several advantages over packed-column salt-bismuth contactors
1 they can be operated under conditions that minimize entrainment of bismuth to the fuel salt returning to the reactor
2 they can be fabricated more economically from graphite and molybdenum components
3 they can handle more easily large flow-rate ratios of tismuth and molten salt
Experimental development of stirred interface contacshytors is being carried out in two different systems a facility in which molten fluoride salt is contacted with bismuth containing a dissolved reductant and a system in which mercury and an aqueous electrolyte phase are used to simulate bismuth and molten salt These two systems and the development work performed during this report period are described in Sects 821 and 822
Table 8J Oven mass transfer coeffkieM for iteodymmm m metal master experiment MTE-3B ran Nd-1
A (mmsec) A (mmsec) A (mmjecr
Measured1 Predicted value value ltlt)
Measured Predicted value value Cr)
Mease bdquod c Predicted value value i^)
00035 39 025 20 013 25
Based on the neodymium in the salt phase 1 I I
bmdash~ - mdash mdashmdashmdash at fluoride salt -Bi -Th interface
I D B
I l
at LiCl-Bi-Th interface
a LiO - Li-6i interface A j km k9Ds
= individual mass transfer coefficient fluoride sail to bismuth - individual man transfer coefftcien bismuth to Tuoride sail = individual man transfer coefficient bismuth In lithium chloride k - individual mass transfer coefficient lithium chloride to bismuth
where
DA - distribution coefficient between fluoride salt and bismuth Dg - distribution coefficient between chloride salt and bismuth Oc distribution coefficient between chloride salt and lithium-bismuth
cAgitator speed is 50 rps
MS
S 2 I Expernieafe win a fecsnmkaly Agitated Nnaaraquoprning Contactnr bull the Salt bull f a i t h
Flolaquortuumgt FariSty
Operation of a facility has continued in which mass transfer rates are being measured between molten LiF-BeF 2 ThF 4 (72-16-12 mok )and molten bismuth m a mechanically agitated nondispeising contactor The equipment consists of a graphite-lined stainless steel vessel salt and bismuth feed and receiver vessels and the contactor vessel h the first of these the salt and bismuth phases are stored between runs The other vessels allow for treatment of the phases with HF and H The comactor consists of a 6-ltn-diain carbon-steel vessel conta rang four I-in -wide vertical baffles The agitator consists of two 3-in-dhm stirrers having four noncanted blades A ^-in-dtam overflow at the intershyface allows removal of interfacial films i f present with the salt and metal effluent streams During a run the salt and bismuth phases are fed to the contactor by conshytrolled pressurization of the respective feed tanks the phases return to the receiver vessels by gravity flow A detailed description of the facility and operating proshycedures has been previously reported A total of nine mass transfer runs have been completed to date along with one hydrodynamic run intended to determine the amount of entrainment of one phase into the other at a sties of different agitator vxeds Results from the nine mass transfer runs have been previously reported ~ i
The experimental proceduie for and results obtained from the hydrodynamic run and treat men of the salt and bismuth with HF and H 2 are discussed in the reshymainder of this section
Experimental operation daring the hydrodynamic ran The hydrodynamic run was performed with salt and bismuth flow rates of M 5 0 and M 4 Q ccmin respectively The agitator was operated at three difshyferent speeds during the run 250310 and 386 rpm At 250 and 310 rpm three sets of unfdtereJ salt and bisshymuth samples from the contactor effluent streams were taken at 4-min intervals Three sets of unfiltered efshyfluent samples were aiso taken with the agitator operatshying at 386 rpm but the samples were taken at 2-min intervals
To avoid contamination of the sample contents with extraneous material the sample capsules were cleaned of foreign matter by the following procedure Gross amounts of salt or bismuth were first removed with a file then the sample capsule was polished with emery cloth and finally (he capsule was washed with acetone
The sample capsules were then cut open with a tubing cutter and the contents of each sample were drilled out
and visual)- inspected for the presence of one phase in the other Ho such evidence of gross entramment was found h some of the salt samples small flecks of metal were noticed which were probably small pieces of the sample capsule produced during the dnamg operation The contests of each sample were then sent to the Ana rytical Chemistry Division for dttuiiannion of brsrmnh present in gt salt samples and berynram present in the bismuth samples h is assumed that any berynmm present in the bismuth is mdkstive of entrained fluoride salt The results of these analyses are given in Table 84 The bismuth concentration in the salt samples shows a general decrease with increasing sarrer speed widi very low values occurring at the highest stirrer speed It also seems evident that the bismuth concentration in the salt phase may have been a function of the run time since after the fourth sample the bismuth concentration reshymained at a relatively constant value of 50 plusmn11 pom which is quite different from the values reported for the first four samples which ranged from 1800 to 155 ppm
These results are significantly higher than those of LindauerJ who saw less than 10 ppm of bismuth in
9 J A Klein el al tnaraquoeerme Development Stmmes far I M l d i U t Breeder Reactor hocesnm So bull ORNL-TS-463 Italy 1975) pp 2 3S
10 C H Brown Jr Engmttii-t Development Studies for Molten Salt Breeder Reactor rYoceomf So 21 ORNL-TM-4X94 (in preparation)
11 J A Kkai tnemeermw Drreiopmenl Studies of Molten-Smll Breeder Reactor Procenmt So IS ORNL-TM-469 (September 1974) pp I 22
12 C H Brown Jr Enjmerrmt Development Studies for Hoten Salt Breeder Reactor rVncezshu Vo 20 ORNL-TM-4810 (in preparation)
13 R B LindraeT fmjmeetmf Drreiopmenl Studies of Molten Salt Breeder Reactor Proceowtt So 17 ORNl-TM-41711 (m preparation)
TaWeS4 Kwmyraquoof ^aXmmhwmmmtn
Agitator speed Bi sample Be in Bi Sail sample Bi in salt (rpm) number (ppm) number (ppm)
250 42 215 437 100 250 429 125 43 205 250 430 215 439 155 310 431 85 440 270 310 432 910 441 53 10 433 442 34
36 434 110 443 64 36 435 175 444 54 36 436 50 445 43
149
fluoride salt in comact with b i t iu fh in several different contacting devices- It is likely that sample i nniiuuni tioa is a contributing factor to the high bcrmdashrh concenshytrations measured Three possible sources of sample coataaunaboa have been reported
I timtjuunitiou by withdrawing Imdashparr through a sample port which has been in contact wkh bismuth
analytical laboratory by the use of equipment roushytinely used for bismuth analyses
3 ctrwfuttiiuTmutftoit from bull hwy^CTWffy vt^tt^f^n^i^^^^UKttf material laquohkh may be floating on the salt surface
Since no maximum peiHUSMuk rate of bismuth eMram-ment in the fuel salt going to the bism ah removal step or m the salt returning to the reactor from the fuel processing plant has been set it is difficult to assess the significance of these results However the bismuth conshycentrations in the salt do not seem to be inordatttelv high at the highest stirrer speed and it seems Bkefy that some degree o f phase dispersal might be tolerated ia order to achieve higher mass transfer rates
The beryflium concentrations in the bismuth samples at each agitator speed show both high and low values with no discernaWe dependence on agitator speed These results agree well with previously reported data1 for beryllium concentration in the bismuth phase during mass transfer runs in this system at agitator speeds of 124 180 and 244 rpm Previous experiments with water-mercury and organic-mercury systems suggest entrainineni of the light phase into the heavy phase at an agitator speed of about 170 rpm The concentration of beryllium in the bismuth phase is not significantly different from previous results observed at lower agitashytor speeds The effect of entrsined fluoride salt in the bismuth would be most detrimental in the metal transshyfer process where fluoride salt in the chloride salt phase decreases the separation factors between thorn m and the rare-earth fission products
H -HF treatment of salt and bismuth The mass transshyfer runs completed to date in he salt-bismuth contactor have all been performed under conditions where the controlling resistance to mass transfer is in the inter-facial salt film One final mass transfer run will be pershyformed in which the bismuth-film mass transfer coeffishycient is measured In preparation for this run the salt and bismuth in the graphite-lined treatment vessel were treated with HF diluted with H 2 to oxidize the reduc-tants present in the bismuth phase The procedure used was essentially that reported previously14 The salt and bismuth at -v-oOOC were sparged with 25 scfh of 30 (mole) HF for 9 hr The HF utilization decreased from
7 5 at the 1 njiiiiini of treatment to 3 5 during the final 2 hr of treatmat Analysis of the ash and bismuth phases before and after treatment with HF and H 2 inshydicated that esaeatiaty a l of the rr duct ant in the bisshymuth phase was oxidized by hydrofluormatioa The mmtmm distribution ratio decreased from 740 molts mole prior to the treatment to OJ03 molemole after the HF-Hj treatment
L U ---r--8 iiiiiT I M I I I M M I U I I - j
We have continued development of a mrrhmii dlj agitated nondispersmg two-phase contactor wing an aqueous electrolyte and mercury to srmmatf mohea salts and bismuth
As previously reported1 we have investigated the feasibility of using a pobrographk technique for measuring electrolyte-film mass transfer coefficients in this type of contactor During this report period we have
1 tested three different anode materials 2 produced cathodk polarization waves corresponding
to the reduction of F e compkxed widi excess oxalate ions at the mercury surface
3 obtained and calibrated a slow-scan controDed-potential cyclic volumeter
4 examined the quinone-hydroquinone redox couple as a possible alternate to the F e -Fe couple now being used
Modifications to experimental equipment With the exshyception of the tests made with the qrinone-hydroquinone redox couple ail tests made during this pr ied were performed with the equipment previously described5
The equipment consists of the 5 X 7 in Plexiglas conshytactor used in previous work with the water-mercury system The mercury surface in the contactor acts as the cathode in the electrochemical cell The cathode is elecshytrically connected to the rest of the circuit by a Vg-in-diam stainless steel rod electrically insulated from the electrolyte phase by a Teflon sheath The anode of the cell is suspended in the aqueous electrolyte phase and consists of a metallic sheet formed to fit the inner perimeter of the Plexigas cell The current through the cell is inferred from the voltage drop across a 01 -SI plusmn 05 10-W precision resistor The signal produced
14 B A Hannaford (l jl Engineering Development Studies for HollenStll breeder Reactor Processing No 3 ORNL-TM-3l3ltMay 1971) p 30
15 C H Brown Jr Engineerin Development Studies for Mitten-Sit Breeder Reactor Processing So 22 ORNL-IM-4041 tin preparation)
ISO
on a on the
electrode
across the i Hevlen-Fackard xjr plotter The x nbtter bull nrodnoed hy the | the mncmy and a (SCE) suspended in the electrolyte |
to studies nun on the a stow-wcan controned-pocentieJ cyclic woks
patentNttat) was obtained fan the Analytical Chemistry Dtaunu to repfacr the Hewlett-Packard dc poawaapfiy iwtiionely wcd-ThecycJCfohnnrtrTiia three electrode mstrumeut which cortroh lraquo i bttnicn the mercury vnfuir and ai reference electrode whle paahag a cnrrent between the auxamry electrode and the mercury surface Voitafes can be itianrJ between tfVw SCE aad -2 Vw SCE ataacanrateaptol Vnnh The posentiostat can carry a carrot of up to 2 5 A between the auxSnry and mtiiury electrodes
npunninli ahh Ihi tt1 fi ililiai Thr rlrriin ryte used for al the experiments performed daring this report period was nouunaPy OJOOI M Ft2 obtained from ferrous sulfate 0X10025 M Fe obtained from ferric salfate and 0 J M potassium oxalate The oxalate ions form a stable complex with both the re and Fltr2
ftriuuif mnmumnm of the Fe1 reduction cdhccdy
Three anode nMcriab have been tested copper iron ml satisfactory polarization -aaves were pro-
I with al three materials However the copper and iron reacted with the electrolyte solution This addishytional uue reaction caned poor lewudacnwwty in the
I could aho p ornery alter the properties of the To amid tins cnobkrn an anode was fabrishy
cated by poring gold on a 0J062$-m-thka sheet of nickel which was formed to fit the inner perimeter of the electrochemical eel
Shown irgt Fig 8 J is a polarogram measured with the electrolyte described above in the 5 X 7 in Plexiglas contactor mag the gold anode with phase volumes of aboat IJ8 liters each and nc agitation The cell current it plotted as a function of the mercury sarface potential vs the SCE The cnrrent racreasts from zero at zero applied potential to a relatively constant value at an applied potential of about -035 V n SCE In this region contbtvons electrolysis is taking place in the cell corresponding to reduction of FetCiO^ 1 ~ at the mershycury cathode In the region of applied potential from -0J5 V vs SCE to -0JO V vs SCE the cell current
OMM 0W6 79- U429
1 1 1 1 1 1 1 S
2 lt
bull0t-M raquo raquo
m m m f~~ 5 u J I
J ew0^45V
ffl 1 1 1 1 1 0 -OJ -02
Fugt laquo3 Catholic bullohriarmi ware for FlaquoC O)
-0 5 -04 -OS VOLTM0C raquobull SCE
-OS -07 -oa
in Ac 5 X 7 J n m l raquo
151
increases only a smal iniaswt here the current is bullanted by ttugt rate of diffusion of the Fe(CzQlaquogtjgt~ to the mercury surface where this ion is rcdnced The difshyfusion current can be related to the nam transfer coefficient through the electrolyte fifan as prcwontly
The half-waw potential is defined at the potential at which the current is equal to one-half the hunting nine Figure 8 J shows the measured half-waw potential for the ferric oxalate coaapiex The half-wane potential of -0245 V measured in the contactor agrees weD with the wine reported in the literature of -024 V vs SCE for the reduction of ferric oxalate
Under ideal conditions the diffusion current is directly proportional to the polarized electrode surface area and the bulk concentration of the hinting km To detennine that the mercury surface was actually being polarized two tests were perfonned First the anode surface area was decreased by about 48 This had no effect on the magnitude of the diffusion current indishycating that the mercury surface (cathode) was polarized rather than the anode surface In the second test the concentration of the ferric ion was doubled but no concomitant increase in diffusion current was seen Since the diffusion current is directly proportional to the concentration of the limiting km (Fe1) the current should haw doubled The only explanation for this behavior is that the Fe had been reduced by some contaminant in the system possibly present in the mershycury This would have caused ferric ions to be present at only a wry low concentration during ceD operationdue to electrolytic oxidation of the ferrous iron
To ebminate the possibility of reductant being present in the mercury a supply of purified mercury was obshytained from the Analytical Chemistry Division A test was performed using the purified mercury and an elecshytrolyte having the same nominal Fe and Fe concenshytrations given abow Preparation of the electrolyte was completed in the absence of oxygen to preclude posshysible oxidation of Fe to Fe Again the anode surshyface area was decreased with no discernible decrease in the diffusion current indicating that the mercury surshyface was polarized An increase of the Fe concentrashytion from M)25 vnM to Mgt3 mW resulted in an inshycrease in the diffusion current by a factor of 2 indishycating that the waw being measured was the ferric ion reduction waw However the half-wave potential was measured to be -07S V vs SCE which is about three times the reported value
To calculate the aqueous-film mass transfer coeffishycient from poiarographic data the bulk concentration of the oxidized species must be accurately known The
n a n K amp j f a u f l l O u l a m m anuCntSnafsEafannTuB a m m nWanuWOnBTBsnnnnnT- ana^ne-w w ^ m w u^m w ^ p p ewajuajuaawmimaaaBmniw ma mi awnwaawgt^pwnnawBwanpap wa^anu
the electrolyte used in dm second of the two ter^jaen-tkmed abow woe analyzed for F e v asm F by this method Results hnhcatrd that the fie and Fe conshycentrations were 17 and 028 mMrespectiwry which is in poor agreement with the expected values of 030 ajtf Fe and 1J0 mmf Fe2 One poanok cause for the poor agreement is that the Ft 1 was oxidized to Fe during the period when the solution was held in the sample bottles However this was not expected since the dec-trotyta had been sparged with argon to remow dissolved oxygen and the sample botdes were purged with argon toremowair
To aid in oetennming if the reported analytical results were in error due to analytical technique or to method of solution preparation two standard solutions were prepared and sampled for analysis One solution was prepared to contain 56 ugim Fe and the other solushytion was prepared to contain 56 ugnd Fe1 Both solushytions were 1 WmKjCzO^HjO Subsequent analytical results indicated that both solutions had essentialy the same concentrations of Fe3 and Fe 1 50 and 27 fignil respectively Farther investigation wnl be necessary to determine the correct method for preparing andor analyzing iron oxalate solutions
Experiments with the qwmame-bydroonmmae system A possible alternate to the Fe -Fe system for measshyuring electrolyte-phase mass transfer coefficients is the reversible reduction of quinone to hydroquinone at the mercury cathode
The reaction under consideration is
C r l 4 0 + 2 H 4 + 2laquo-CHlaquo(OH) ( I )
Since hydrogen ion as wen as quinone is a reacting material a strong buffer must be present to serve as a supporting electrolyte The buffer causes the H conshycentration to be essentially constant across the inter-facial electrolyte film because the rate at which the buffer equilibrium is established is reiatiwfy rapid comshypared with the quinone diffusion rate1
A quaUtatiw test was made with the quinone system to determine whether acceptable polarization waves couM be measured and to determine whether the quishynone electrolyte is inert to mercury The electrolyte was 001 M hydroquinone and 0005 M quinone with a 0O5 M phosphate buffer at a pH of 70 Satisfactory polari-
16 i M Kolfhoff and 11 Latcanc p 44 inbfaromvp Intencfcnce New Yortt 146
I C A Lin el at Dirruson-Controiled Electrode Reacshytions Ind Eng Ckem 43 2136-43 (1951)
1S2
abon waves were obtained in a small cell with a large copper anode and a mercury pool cathode The electroshylyte was chemically inert to mercury during the tests The color of the quinone electrolyte changed from a light yellow to deep brown within several hours This phenomenon is due to the decomposition of quinone by ultraviolet light Further studies in the S X 7 in contacshytor will be done to determine whether tins system is suitable for mass transfer measurements
8 3 C0NTTNU0USFLU0IUNATOR DEVELOTMENT
R B Lindaucr
Continuous fluorinators arc used at two points in the reference flowsheet for MSBR processing The first of these is the primary fluorinator where 99 of the uranium is removed from the fuel salt prior to the reshymoval of 2 J J P a by reductive extraction The second point is where uranium produced by decay o f 2 Pa is removed from the secondary fluoride salt in the protacshytinium decay tank circuit These fluorinators will be protected from fluorine corrosion by frozen-salt layers formed on the internal surfaces of the fluorinator which are exposed to both fluorine and molten salt To keep frozen materia on the walls while maintaining a molten-salt core in the fluorinator an internal heat source is necessary to support the temperature gradient Heat from decay of the fission products in the salt will be used in the processing plant However to test frozen- JI fluorinators in nonradioactive systems
another internal heat source which is not attacked by fluorine is needed Since electrolytic or autoresistance heating of molten salt has proven to be a feasible means fx providing this heat source studies of auforesbtance ucating of molten salts are continuing A conceptual design was made for a continuous fluorinator experishymental facility (CFEF) to demonstrate fluorination in a vessel protected by a frozen-salt film Design was comshypleted and installation was begun of a fluorine disposal system in Building 7503 which uses a vertical spray tower and a recirculating KOH solution Installation was completed of equipment to demonstrate the effectiveshyness of a frozen-salt film as protection against fluorine corrosion in a molten salt system
8 J I autafetmi and Initial Operation of Aaloteststance Heating Test AHT-4
Equipment for autoresistance heating test AHT-4 was installed in ceil J of Building 4S0S fai this system (Fig 84) molten LiF-BeFj-ThF (72-16-12 mole 7r) is cirshyculated by means of an argon gas lift from a surge tank to a gas-liquid separator from which the salt flows by gravity through the autoresistance electrode through the test vessel and returns from the bottom of the test vessel to the surge tank The test vessel (Fig 85) used in experiment AHT-3 was decontaminated equipped with new cooling coils heaters and thermocouples and reinstalled for experiment AHT-4
The test vessel is made of 6-in sched-40 nickel pipe with a 44-in-)ong (II-m) cooled section from the elecshytrode to below the gas Inlet side arm The cooled secshytion is divided into five separate zones each with two
Oflm 0tJngt 79mdash4W5
bullbullOfF-CAS-
j M M N m laquo$urr|
SCMMTOft
JT~f
i II lraquo li II I I I I
Hi
HEAT FLOWMETER
AUTOMESISTANCC HCATIN6 POWER
SUff lV TEST
VESSEL
ARGON
Fig SA Ftowdwet for autoresifUncc heating test AHT-4
153
Ffc85 AHT-4 lest vewd
154
parallel coils through which an air-water mixture flows The gas outlet section above the salt level has an inshycreased diameter for gas-calt disengagement and is made of 8-io sched-40 pipe The surge tank has a 46-m4ong (I _2-m) 6-in-diam (01 S-m) section to provide submershygence for the gas lift The upper section of the surge tank is 24 in (0-61 m) in diameter and provides suffishycient capacity to contain the salt inventory for the enshytire system The gas-liquid separator is an 8-in-diam (O^Om) conical-bottom vessel with baffles and York mesh in the upper part for gas-liquid disengagement m the heat flowmeter the salt is heated by an internal cartridge heater and the flow rate is calculated from the heat input and ihe temperature iise of the uit stream
The system is started up by heating the equipment and Hnes to 600C (873degK) The argon gas lift is started and initially the salt flow rate is determined by the decrease in surge-tank liquid level After the salt levels in the tank separator and test vessel are constant cooling of the test vessel is started The resistance beshytween the high-voltage electrode and the test vessel walls is checked periodically by applying a low voltage
to the electrode and measuring the current As cooling progresses this resistance wul increase until the point is reached where heat can be produced in the salt at a significant rate (several hundred watts) without cauang a reduction (shorting) of the resistance
The 80-liter salt batch was charged to the surge tank and after minor modifications to the heating system operation was started Four preliminary runs were made lasting from 4 to 12 hr (from the time the gas lift was started until plugging occurred) In the first run plugging apparently occurred in the electrode when the liquid level in the separator fefl too low to provide sufshyficient head for flow to the test vessel
Salt flow in the second run was much smoother and circulation continued for 11 hr without adjustment of the gas lift During this time the test vessel was being cooled and the salt flow rate slowly decreased by V7 from 450 to 425 cnvVmin This was probably caused by an increase in salt viscosity a buildup of frozen salt in the test vessel or a combination of the two The steady salt flow rate and higher salt temperature fgt873 0K and 20-3TK higher than in run No 1) kept the electrode from freezing but the heat supply at the bottom of the test vessel was insufficient to keep the salt outlet from freezing which terminated run 2 The resistance beshytween the high-voltage electrode and the vessel waO increased from 001 to 0X1812 but autoresistance heatshying was not attempted The vertical portion of the test
section had been cooled to 639degK (sobdus temperature 623degK)
Before the third run the output of the powerstat conshytrolling the test vessel bottom heaters was increased by 44 to keep the salt outlet above the freezing point The ran was terminated by salt freezing in the elecshytrode This resulted from too low a salt flow rale (the heat flowmeter was inoperative because of a burned out heater) and too low an initial temperature (723degK vs 823degK in the second run) in the vertical section of the side arm through which the electrode passes
The fourth run was started with some heat on the vertical section of the side arm This section was unshyhealed prenocty As coohng progressed the bottom heaters on the test vessel were inadequate at the salt flow rate being used Increasing the salt flow rate preshyvented freezing at the bottom of the test vessel After 754 hr of operation the liquid levels in the separator and test vessel started to increase indicating salt flow probshylems both at the inlet and exit of the test vessel Alshythough the salt resistance had only increased from OX) I to 003 ft and the average test vessel wall temperature (in the cooled zone) was 658degK autoresistance heating was suited This freed the plug in the electrode allowshying salt flow from the separator to the test vessel and the increased flow raised the test vessel bottom tempershyature and flow resumed from the test vessel However salt flow rates were erratic for the next 2 hrand 9K hr after the start of the run the tert vessel level started to rise indicating a frozen salt restriction in the vessel It was decided to try to transfer the molten salt from the test vessel to the surge tank before complete plugging occurred This was done successfully and 56 liters of salt was transferred to the surge tank After cooling radiographs were taken of the test vessel by the Inspecshytion Engineering Department using a 35-Ci J l r source In the test section of the test vessel radiation penetration was insufficient to permit measurement of the film thickness The bottom of the vessel between the salt outlet and the gas inlet was free of salt as exshypected and the radiograph of flu top of the vessel showed a 25-mm-thick ring of salt above the normal liquid level This is salt deposited on the colder pipe wall by the action of the gas bubbling through the salt Calculations from the volume of salt transferred indishycated an average film thickness of 45 mm (a 65-mm-diam molten core) The salt resistance at the end of the run was 018 ft and the maximum autoresistance heatshying used was 450 W
The main problem seems to be the forming of a unishyform salt film Near the electrode where the hot molten
155
salt enters cooling is much slower than in the vertical section above the gas inlet It is probably in the vertical section where the salt flm becomes too thick and reshystricts the salt flow
8J2 o f Facaty(CFEF)
The purpose of the CFEF is to measure the perforshymance of a continuous fluorinator which has frozea-wali corrosion protection in terms of uranium removal The uranium which is not volatilized but is oxidized to UFs wfll be reduced back to UFlaquo in a hydrogen reducshytion column The facility wul be used to obtain operatshying experience and process data including fluorine utilishyzation reaction rate and flow-fate effects and to demonstrate protection igainst corrosion using a frozen salt Aim
The facility will be installed in a ceD in Buflding 7503 to provide beryllium containment The system wfll conshytain about 8 ft 3 (023 m J ) of MSBR fuel carrier salt (72-I6-I2 mole 3 LiF BeF -ThF4) containing OJS mole ltpound uranium initially The salt wiD be circulated through the system at rates up to 50 of MSBR flow rate (67 X I 0 m 3xc) Because of the short fluorishynator height (1 to 2 m) the amount of uranium volatilshyized will be between pound0 and 95 per pass The variables
of salt flow rate fluorine flow rate and fluorine conshycentration wil be studied by measuring the UFlaquo conshycentration in the fluorinator off-fas stream and by sam-pKrg the salt stream after reduction of UF to UF 4 The fluorinator laquo 4 have two fluorine inlets to provide data for determining the column end effects Reduction of UF 5 war be carried out in a gas lift in which hydroshygen will be used as the driving gu and also as die reduc-tant If additional reduction B required tins can be done in the salt surge tank The surge tank is designed to provide sufficient salt inventory for about 10 hr of fluorination with 95$ uranium volarihntion per pass About 99 of the uranium should have been removed from the salt batch after this period of time
The faculty flowsheet is shown in Fig 86 Salt wil enter the fluorinator through the electrode m a side arm out of the fluorine path The electrode flange wil be insulated from the rest of the fluorinator and the auto-resistance power wiD be connected to a lug on the flange The salt wfll leave at the bottom of the fluorishynator below the fluorine inlet side arm The fluorinator wall wiD be cooled by external air-water cons to form the frozen salt film which wfll serve the dual purpose of preventing nickel corrosion and of providing an electrishycally insulating film for the autorcsistance current Below the fluorine inlet the fluorinator waB will not be cooled and the molten salt wul complete the electrical
TO FLuomnc ftSPOSM STSTU
JVTO-K S S T M C C ~ T M M
TCU f
ifSEMMUl
r-Gf=imdashlaquobullmdash^ni
TOorr-cts
^ - bull I I I T Z
FMCZC VMVC
MPWCTNM COLUMN
CAS-LIFT
HVOMMCR
rO F K M I VMVI
Fit HA Conf immu flaottnalor experimental facility flow Acer
156
OfML DWG 75-15057
FLUOMNE-CONTMHNG U S
TO N 0 T OFF-GAS SYSTEM
Fjs87 Ftmnmt4mfpmtwfmtm
nrcuit to the vessel wall Since all of the uranium will not be volatilized from the salt there will be some UF 5
in the salt at the bottom of the fluorinator The luori-nator bottom exit line and reductio- column will be protected from the highly corrosive UF 5 by gold lining or plating The molten salt containing UF S will enter the bottom of the column where the salt wit be conshytacted with hydrogen The hydrogen will enter through a palladium tube which will result in the formation of atomic hydrogen and greatly increase the reduction rate to UF 4 The hydrogen reduction column will also act as a gas lift to raise the salt to i gas-liquid separator The salt will then flow by gravity to the fluorinator through a salt sampler surge tank heat flowmeter and electrical circuit-breaking pot Off-gas from the separator which contains HF and excess hydrogen will pass through an NaF bed for removal of the HF Uranium ixxafluoride from the fluorinator will also be removed by NaF Mass flowmeters before and after the NaF beds will be used to continuously measure the UFA flow rate
83J Fluorine Disposal System for Building 7503
The CFEF (Sect 832) will be the first test of the frozen-wall fluorinator using fluorine For the disposal of the excess fluorine a vertical scrubber is being inshy
stalled in Building 7503 A flow diagram of the system is shown in Fig 87 The scrubber is a o-in-diam 8-ft-bJgh (015- by 24-m) Mond pipe with three spray nozzles in the upper half of the vessel The surge lank contains 200 gal (09S m) of an aqueous solution conshytaining 15 wt KOH and 5 wt Kl This equipment is designed to be able to dispose of one trailer of fluorine (18 std m 3 ) at a flow rate of 12 scfm (9 X 10 std msec) The KOH solution wil be circulated through the spray nozzles at a total flow rate of 15 gpm (OJOOI msec) The fluorinator off-gas stream will flow cocur-rently with tnis stream The scrubber exit stream passes through a photometric analyzer for monitoring the efficiency of the scrubber
8J4 Frozen-Wafl Corrosion Protection Denomtration
Equipment has been installed for demonstrating that a frozen salt film will protect a nickel vessel against fluoshyrine corrosion ty preventing the NiFj corrosion prodshyuct film from being dissolved in the molten salt A small vessel containing 6 X I 0 1 m 1 of molten LiF-BeFj-ThF4 (72-W 12 mole ) will be used for the demonshystration (Fig 88) The fluorine inlet consists o hree concentric tubes which provide a path for an air coolant
157
FLUOraquoK IN
JL
SALT IXVCL-
OuT
- raquo F L laquo O M OUT
FlaquoSJ Ffi
stream that will be used for freezing a salt film on the outside of the outer tube The wall of the inner lube through which the fluorine will flow is 31 nils (079 mm) thick The inner lube of the fluorine inlet will not be protected from corrosion The vessel wall is also unprotected but is 280 mils (711 mm) thick Fluorine will be passed at a low flow rate (-v830 mmsec) through the salt until failure occurs which is expected in less than 100 hr at the tip of the probe near the gas-liquid-foiid interface Wall thickness measurements before and after the demonstration will show to what extent the salt film afforded protection
A flow diagram for the system is shown in Fig 89 The argon back pressure will be recorded to provide an ndication of corrosive failure Failure of the tube below
the salt film will allow some salt to leak into the argon cooling annulus The salt will be entrained up into the cool portion of annular space causing a restriction to
the argon flow The system waf be designed such that the fluorine flow is terminated automaticaly when either a low argon pressure is detected in the anrndus or when a high argon back pressure occurs
84 FUiaiWCONSnTUnON ENCINEEJUNC OEVELOTMENT
llMCounce
The reference flowsheet for processing the fuel salt from an MSBR is based upon removal of uranium by fluorinatioa to UFraquo as the first processing step 1 The uranium removed in this step must subsequently braquo reshyturned to the fuel carrier sal before i u return to the reactor The method for recombiniag the uranium with the fuel carrier salt (reconstituting the fuel salt) consists in absorbing gaseous UFraquo into a recycled fuel salt stream containing dissolved U F 4 affording to the reacshytion
UF f c(g)UF4ld) = 2UF(draquo laquo2raquo
The resultant UF S would be reduced to U F 4 with hydrogen in a separate vessel according to the reaction
U F ltdgt bull H (ggt = UFlaquo(d) bull HF(ggt (31
Engineering studies of the fuel reconstitution step are being started to provide the technology necessary for
the design of larger equipment for recomputing UFraquo generated in fluorinators in the processing plant with the processed fuel carrier salt returning to the reactor During this report period equipment previously deshyscribed was fabricated and has been installed in the high-bay area of Building 7503 This report describes instrumentation for off-gas analysis including a prelimishynary calibration curve and two alternatives for proshyviding corrosion-resistani gold linings for equipment to be installed later
The nickel reaction vessels presently installed will be used to test the salt metering devices and gas supply systems After the initial shakedown work is completed the UFraquo absorption vessel Hj reduction column flowing-stream samplers and associated transfer lines will be replaced with gold or gold-lined equipment Gold is being used because of i u resistance to corrosion by UFraquo gas and U F dissolve in the salt
1972 18 Chem Technol Dh Anim frogr Kept Mar SI ORNL-4794p I
19 R M (ounce Engineering Development Studies for MolenStll Breeder Reactor Processing So 19 ORNL-TM-4863 (July 1975) pp 38 42
158
OMN M 6 rS-OTM
FCV-3 nOccWM HASTMGS MASS FLOWMETER
ACTIVATED ALUMNA TRAP
Ffeft9 FfocM ait BtotaciiMi
841 for Analyzing Vest Off-Goes
The equipment for the second phase of the experishyment will consist of a feed tank a UF absorption vesshysel an Hj reduction column flowing-stream samplers a receivei tank NaF traps for collecting excess UF and for disposing of HF gas supplies for argon hydrogen nitrogen and UFraquo and means for analyzing the gas streams from the reaction vessels (Fig 810) The equipshyment wul be operated by pressurizing the feed tank with argon in order to displace salt from the feed tank to the UFlaquo absorption vessel From the UFlaquo absorption vessel the salt flows by gravity through a flowing-stream sampler into the H2 reduction column From the Hj reduction column the salt flows by gravity through a flowing-stream sampler to the receiver tank Absorption of gaseous UF t by reaction with dissolved UF 4 wiD occur in the IFF absorption vessel and the resultant UF5 will be reduced by hydrogen in the Hi reduction column The effluent salt is collected in the receiver tank for return to the feed tank at the end of the run
The off-gas from the absorption vessel and the reducshytion column will be analyzed for UF and for HF reshyspectively
The respective off-gas streams will be continuously analyzed with the use of the Cow-Mac gas density balance A sample stream is taken from the main off-gas stream and passed through the balance for analysis (Fig 811) These analyses wiO be used in determining the efficiencies of UF absorption and H 2 utilization
The efficiency of UF absorption will be determined by metering UF and Ax to the UF reaction vessel and determining the UF content in the vessel off-gas using a model 11-373 Cow-Mac gas density cell2 The H utilization will be determined similarly Hydrogen will be metered to the H 2 reduction column and the column off-gas wD be anayzed for Hj content also using a model 11-373 Cow-Mac gas density ceD The Cow-Mac cell commonly used as a gas chromatograph
20 Gow-Mac Instrument Company 100 King Road Madison New Jersey
159
bullWLDIN6
bull SYSTEM
Flaquo SIO Ftow lt ^ w o gt n ^ w i l M
msw NEACnON VflaquoSCL
P9E Y
f OWL DUG 7VS909
0FF-6AS
j r _^DT
KOC
ROTCTER|V] $
Ffc 811 SdMMMtic M of fMl ncomtitalfcM experiment off-gn
160
detector provides a continuous signal which varies directly with the density of the sample gas allowing continuous analysis of the sample gas stream with accushyracies of 3 to 4ft Because the detector elements are not exposed to the sample stream the gas density cell is useful in analyzing corrosive gas mixtures
Nitrogen and argon will be reference gases for the gas density cells used for analyzing the off-gas from the UF absorption vessel and the H reduction column respectively The response of the gas density cell is fairly insensitive to changes in the sample gas flow rate when nitrogen or argon is used as a reference gas2 z To measure varying Ar-UF and H2-HF ratios with the gas density detectors it is necessary to control the refershyence gas flow rate precisely However Irigh precision is not required for controlling the sampie g^ flow rate The reference gas flow rates are controlled sufficiently by rotameter and separate gas supply systems A satisshyfactory means for providing reproducible sample flow rates has been developed The sample stream is taken from the main off-gas stream (Fig 811) and flows through a capillary tube the gas densiiy detector an NaF trap to remove the corrosive constituent (UF or HF) and a bubbler to provide a constant downstream pressure The pressure upstream from the capillary is maintained at a higher constant value by means of a similar bubbler in the off-gas line downstream from the NaF trap The NaF traps provide sufficient volume in the lines so that small pressure fluctuations from bubshybles in the process vessels and in the bubblers are effecshytively damped out The flow rate is not constant (although it is reproducible) because as the concentrashytion of the sample gas changes its viscosity changes producing changes in sample flow rate under the prevailshying conditions These flow rate changes superimposed upon concentration changes in the sample stream to the gas density detector result in a nonlinear response of the gas density detector to changes in concentration The effects are reproducible however and a reproducible calibration can be obtained Such a calibration was obtained with mixtures of hydrogen and nitrogen (Fig 812)
For sample gases containing hydrogen and at refershyence gas flow rates below a certain critical flow rate hydrogen will diffuse countercurrently into the refershyence gas stream to the area of the detector elements
21 J T Wjfoh and D M Roue tor Oiromalofr US) 232 40 17)
22 C L Ouillemm and M K Auricourf (its Chromalogr I 24 29 (October 1963)
onw MG re-mo
i i i 1 bull mdash I I I I i DO 90 0
2
Ffc 812 Cafeoraam i laquo of Gow-Mac gas Oettmtf ccM MOM in fad iccoasMatioa t^mtimj claquojlaquoipmlaquoi for H ami N-
Due to the high thermal conductivity vf H the back diffusion of H can greatly affect the sensitivity of the gas density cell However if sufficiently high reference flow rates are maintained this problem can be overshycome
842 Design of the Second Fuel Reconftitutkm EjtgMecimg Experiment
The design of equipmeni for the second fuel reconsti-lution engineering experiment (FREE-2) is continuing The equipmeni for FREE-2 will be similar in design to the equipment for experiment FREE-I except for the addition of an intermediate liquid-phase sample port beshytween the UFraquo absorption vessel and the H 2 reduction column (Fig 810) In addition all vessels and transfer lines exposed to dissolved UF 5 with the possible excepshytion of the receiver lank will be gold or gold lined Gold sheet 0010 if (02S mm) thick is on hand for the fabricated liner of the UF absorption vessel Two altershynative exist for lining the H 2 reduction column and the receiver vessel interior gold plating or a fabricated gold liner
The minimum plating thickness that would probably provide a pinhole-free liniig is approximately 0005 in (013 mm) The minimum thickness for a fabricated gold liner in vessels of this size is approximately 0010
161
in (025 mm) Fabricated gold liners are economically competitive with gold plating in the thicknesses menshytioned because gold sheet is available at ERDA prccious-mctal account prices approximately S3499troy oz (SII3g) and gold in commercial gold-plating solutions is available only at market prices of about Sl64troy oz (S5J7g) as of June 18 1975 Some comparisons important in the choice between interior gold plating or fabrication of a gold liner are
1 the technology involved in fabricating a welded gold vessel is available while some technology would need to be developed for interior plating of vessels having a high lengthdiameter ratio such as the H2
reduction column 2 the time involved in both approaches is approxishy
mately the same 3 the plating will be difficult to inspect and there will
be no guarantee of pinhok-free coverage while dye penetrant examination of welded joints is available for a fabricated liner
Because it is unclear whether there is sufficient gold in the ERDA precious-metals account for lining the reshyceive tank liner gold plating is favored There is the ziditional alternative bullbull not lining the receiver tank since i orrosion of the receiver vessel by UF5 in the salt could ie tolerated and corrosion products could be reshymoved by hydrogen reduction and filtration between runs
85 CONCEPTUAL DESIGN OF A MOLTEN-SALT BREEDER REACTOR FUEL PROCESSING
ENGINEERING CENTER
D I Gray J R Hightower Jr
A conceptual design is being prepared to define the scope estimated final design and construction costs method of accomplishment and schedules for a proshyposed MSBR Fuel Processing Engineering Center (FPEC) The proposed building will provide space for the preparation and purification of fluoride sail mixshytures required by the Molten-Salt Reactor Programfor intermediate- and large-scale engineering experiments associated with the development of components reshyquired for the continuous processing capability for an MSBR and for laboratories maintenance work areas and offices for the research and development personnel assigned to the FPEC
bullORNI Knpneeriti Division
The project wSI consist of a nev three-story engineershying development center approximately 156 ft (475 m) wide by 172 ft (524 m) long The building will have a gross floor area and volume of 54300 ft 2 (5100 m x ) and 1218J0O0 ft J (34300 m J ) respectively and vhB be constructed of reinforced concrete structural sled concrete Mock masonry and insulated metal paneling The building will be sealed and will be operated at negashytive pressures of up to 0 J in of HjO (75 Pa) to provide containment of toxic materials The FPEC wit be located in the 7900 area approximately 300 ft (91 m) west-southwest of the High Flux Isotope Reactor The engineering center will contain
1 Seven multipurpose laboratories buu on a 24 X 24 ft (7 J X 7 3 m) module for laboratory-scale experishyments requiring glove boxes and walk-in hoods
2 A high-bay area 84 X 126 ft (256 X 384 m) equipped with a 10-ton (9000-kg) crane for large-scale development of processes and equipment for fuel processing at the pilot-plant level
3 A facility for preparing and purifying 16000 kg per ye-r of fluoride salt mixtures needed for the Molten-Salt Reactor Program
4 Support facilities including counting room process control rooms change rooms lunch and conference room and data processing room
5 Fabrication and repair shop decontamination room and clean storage areas
6 A truck air lock to prevent excessive ingress of outshyside air during movement of large equipment items into and out of the high-bay area
7 Two 5-ton (4500-kg) service elevators one inside the building to service the regulated areas and one outshyside to service the clean areas and to move filters to filter housings on the third floor and roof
8 General service and building auxiliaries including special gas distribution systems liquid and solid waste collection and disposal and filtered air-handling and off-gas scrubbing facilities
The experimental program planned for the building involves large engineering experiments that use 2 1 U 2 T h Be hazardous gases i F a H 2 and HF) molten bismuth and various fluoride and chloride salts Inishytially radioactivity will be limited to that necessary for low-level beta-gamma tracer experiments The laborashytory area can later be upgraded if desired for use with alpha-emitting materials at levels up to I kg of n P u
The laboratory area will consist of seven 24 X 24 ft (73 X 73 m) modular-type laboratories and a general-purpose room Bench-scale experiments of the type now performed in buildings 4505 3592 and 3541 will be
162
carried out m these laboratories FtoMems encountered in the large-scale experiments can be studied via smaE subsystems Inert-atmosphere glove boxes wil provide space for examination of samples removed from both the large and the small experiments The laboratory area wul be maintained at a negative pressure of 0 J m of H 2 0(75Pa)
The high-bay area wul be the main experimental area where large engineering experiments wifl be performed Experiments wnl involve circulating mohen mixtures of LiF-neFj-ThF4 lithium chloride and molten Bi-Li alloys The experiments wffl also use elemental fluorine hydrogen fluoride hydrogen chloride and hydrogen gases as reactants and wnl use purified argon for purgshying Excess fluorine hydrogen fluoride and hydrogen chloride wil be neutralized in a caustic scrubber using KOH solutions and the cleaned and filtered off-gas win be ducted to a bunding exhaust system The experishymental equipment and components wil be housed in steel cubicles with floor pans which can contain any salt spJO The cumdes wnl be maintained at a negative presshysure with respect to the high-bay ambient The high-bay area can be supplied with up to 45000 cfm (212 msec) of air The air can be from recirculated inside
air laquo fresh ak from the outside The high-bay exhaust system wil be designed for 30jOOOcfm ( I 4 J msec)at floor level and 50000 cfn (236 msec) at the roof framing level A l exhaust ducts wnl contain fire barriers upstream from the double HEP A filter banks
The salt preparation and purification area wil consist of a 25-ft-wide by 3S-ft4ong by 14-ft-hJgh (76 X 107 X 4J m) raw materials storage room a 22 X 22 X 28-ft-high (67 X 67 X 8J m) room for weighing and blending the salt constituents and a 40-ft-wide by 45-ft-loug by 28-ft-high (122 X 137 X 85 m) room for melting rk-HF treating and filtering the fluoride salt mixtures This facility should be capable of producing I6j000 kg per year of fluoride salt mixtures using the batch processing method in use at the (acuity at Y-12
The estimated cost for the FPEC is SI 5000000 of which $5200000 provides for inflation during the three years required for design and construction of the baking
The design is essentially complete and the conceptual design report is scheduled to be issued in September 1975 Authorization for this project will be proposed for FY 1978
Part 5 Salt Production
9- Production of Fluoride Sak Mixtures I
F L Daley
A salt production facility is operated by the Fluoride Salt Production Group for preparation of salt mixtures required by experimenters in the MSR Program The group is responsible for blending purifying and packshyaging salt of the required compositions
Much of the salt produced is used in studies on Hast el -loy N development in which the concentrations of metal fluorides particularly nickelironand chromium are important study parameters Ic is thus desirable to use salt in which the concentrations of these metal fluorides are low and also reproducible from one salt batch to the next Oxides are undesirable salt contamishynants primarily because of the adverse effect of uranium precipitation and also because of the effect of oxides on corrosion behavior of the salt Sulfur is another conshytaminant present in the raw materials used for preparing salt mixtures Sulfur is quite destructive to nickel-based alloys at temperatures above 350degC because a nckel -nickel sulfide eutectic which melts at about 645degC penetrates the grain boundaries and leads tc inlergrlaquonu-lar attack of the metal The maximum desired ievels for these contaminants in the fluoride salt mixtures are iron 50 ppm chromium 25 ppm nickel 20 ppmsulshyfur lt5 ppm oxygen lt30 ppm Other duties of the group include procurement of raw materials construcshytion and installation of processing equipment and reshyfinement of process operating methods based on results from operation of the production facility
When the facility was reactivated during 1974 initial production was carried out in existing small-scale (8-in-
bullConMiliam
r MSR Program Research and Development
RWttorton
diam) reactors while new large-scale (I2-in-diam) reacshytors were eing installed Experience with both the small and laige units is summarized in the remainder of this chapter
91 QUANTITIES OF SALT PRODUCED
The 3-in-diam reactor was used for production from startup of the program in early 1974 through the first three months of 1975 During this period a total of nine full-scale batches (315 kg total) were processed and made available to investigators Salt from the nine batches was shipped in a total of 2i containers of apshypropriate sizes In general operation of the 8-in-diam reactor proceeded smoothly and the resulting salt was of acceptable composition and purity
Production in the 12-in-diam reactor was started in March 1975 Five production runs each involving about 150 kg of salt have been carried out Of the five salt batches processed four were suitable for use most of the salt from these four runs was used for fuel procshyessing experiments In contrast to the earlier runs in the 8-in -diam reactor difficulty has been observed in the 12-in-diam reactor with corrosion of dip lines in the meltdown vessel and with increasing concentrations of metallic impurities in the product salt
92 OPERATING EXPERIENCE IN l2-in-diani REACTOR
Operating data from the five production runs in the 12-in reactor are summarized in Table 91 Analyses of the resulting salt batches are given in Table 92 A description of the processing operations and conditions
164
TaMe9l ttoccMag fab derived fto to rave taae ami titntioa of iafci aad oatlet flows
Batch number (FS-)
Batch size
ltkgt
Total tarn Ihr)
HF in
(moles) in
(motes)
HF out
(molest
HF reacted (moles)
Dariag hydmlhoriaatiMi 101 150 125 1953 4253 1712 241 102 150 1025 2331 2738 2331 0 103 150 975 1808 2603 1419 389 104 150 95 2853 2473 2434 399 105 12 140 3752 2857 1877 1876
Batch number |FS-)
Batch size
Total time
Total H in
Total HF out
HF in otT-jraquos Imeq per liter of H) Batch
number |FS-) Ike) (hr) (moles) (moles) Start Finish
Daring hydrogen ledacliua
101 150 176 4725 0026 00018 00064 102 150 186 4995 0595 0100 0O50 103 150 244 6520 1560 0625 0016 104 150 440 12040 2180 0746 0008 105 112 320 8514 3290 0476 0102
Table 92 Aaatyxsof 1501 batches of LiF-BeF -ThF4 (72-16-12 mole )
prodaced in die 12-araquo learior
Batch number (FS-)
Analyses Batch
number (FS-) Li r)
Be Th F rlt)
Fe (ppni)
Cr (ppml
Ni (ppml
S (ppnw
O (ppm)
Nominal 72-1612 790 228 4411 4571
101 795 252 4392 4620 82 24 17 737 lt25 102 8 64 222 4200 4600 75 30 600 80 360 103 811 231 4327 4574 60 25 8 25 350 104 839 200 4381 4532 85 65 10 91 NO 105 1046 290 3435 5125 82r 25 8 576
prevailing during hydrofluorination and hydrogen reduction is given in the remainder of this section
921 Charging and Metting of Raw Materials
The salt produced in the l2-laquoi-diam reactor has been of the MSBR fuel carrier salt compostion (72-16-12 mcle LiF-BeFj-ThF4) production of salt of this composition will continue except that some batches will also contain 03 mole UF 4 If the production schedule permits an inventory of non-uranium-bearing salt will be accumulated before beginning the producshytion of uranium-bearing salt The LiF raw material for
the salt production facility is supplied by Y-12 as needed the BeF2 and ThF 4 are taken from raw mateshyrials that have been on hand for several years The only apparent effect of the long storage time on the raw materials is an increased moisture content of the BeF2
The production unit includes two l2-in-diam 72-in-high type 304 stainless steel vessels each of which is (Wed internally with a full-length open-top copper cylinder in which the salt is contained One vessel is used for batch melting of the raw material) which are charged to the meltdown vessel by gravity transfer through a 2-in-diam pipe the pipe extends into a weighing and charging room and is closed by a sealing
165
flange except during the loading operation The second unit the processing vessel is identical to the meltdown vessel except for the charging line Both vessels are fitted with dip lines for introducing gas to the bottom of the vessels for mixing or purifying a salt batch and both are connected to an off-gas system Each vessel is supported in a stainless steel liner and while in use is located in a heavy-duty electrical furnace The receiver vessel to which the salt product is transferred is 12 in in diameter 36 in high and is supported similarly in a furnace adjacent to the processing vessel furnace Salt transfer lines from the meltdown vessel to the procshyessing vessel and from the processing vessel to the reshyceiver are autoresistance heated via a 24-V power supply
The operational sequence includes salt charging meltshying and mixing in the meltdown vessel and transfer of the resulting salt to the processing vessel for purificashytion The process steps include hydrofluorirution hydrogen reduction and filtration during transfer of the purified salt from the processing vessel to the receiver vessel During both the hydrofluorination and hydrogen reduction steps the receiver and processing vessels are maintained at the same temperature and the process gases are passed through the receiver before being fed to the processing vessel in order to eliminate any oxide film on the interior of the receiver
The raw materials are loaded into the meltdown vessel by technicians wearing air suits having a supply of cooled fresh air The work is carried out in a small enclosed room in which containment is maintained by positive flow of air through the room to a bank of absolute filters The appropriate quantities of each of the raw materials are weighed and charged through a loading chute directly into the l2-in-diam melidown vessel which is at room temperature The larger lumps of BeF 2 and occasional lumps of LiF are broken by hand to facilitate loading and to provide improved mixshy
ing The ThF 4 is a fine powder which does not require six reduction The charging method leaves much to be desired melting would be more rapid and more predictshyable i f the particle size of the raw materials could be reduced and all components mixed well before they are charged to the meltdown vessel
Some of the more important impurities in the raw materials are listed in Table 9 3 The values shown are average values in most cases The metallic impurities are satisfactorily low however sulfur and possible silicon contribute to corrosion problems during melting of the raw matercls The moisture content of the raw mateshyrials is not shown but is an important parameter It is believed that hydrolysis of the fluorides during the initial heating period generates hydrofluoric add which subsequently reacts with sulfur- and silicon-containing compounds in the raw materials to form hydrogen sulshyfide and fluoroalidc add The quantities of these mateshyrials produced appear to be dependent on the temperashyture at which the meltdown vessel is held during the initial portion of the melting operation with 2 S proshyduction being most noticeable at temperatures above S00degC An addic compound which contains silicon and fluorine is evolved freely at lower temperatures in the 125 to 500degC range however the extent to which the material is corrosive to the meltdown vessel is not known Analytical data necessary to determine whether these low-temperature gases contain sulfur-bearing comshypounds are not available
The major effect of hydrogen sulfide on nickel comshyponents at temperatures in the rage 600 to 700degC is rapid eirbtlement of the nickel This action has resulted in breakage of dip legs in the meltdown vessel at the rate of one dip leg per run Breakage v observed to occur in the gas space above the melt and the broken dip leg falls to the bottom of the meltdown vessel where it is available for further attack by corrosive material) dissolved in the salt After melting batch
TaMe 93 Impr i t in tm raw material mtei ia ftmoriit a l t production (ppm)
Component S Si Fe Cr
Component Av Max A Max Av Max AVK Max
L i l 21 44 100 IllO 20 25 lt l lt l BeF 300 500 IHO I0O 50 100 20 40 rl ir- lt M 0 ltIO0 lt IO ltin 25 62 I I 17 Mixed raw
material^ ino 131 47 47 26 56 9 15
Mix ture required to produce tali havirfi compofll ion of 72-16-12 mole i I i l - B e l - I h i -
166
FS-101 was passed through a nickel filter having a mean pore size c f 40 i but plugging of the filter on subshysequent transfers led to its removal from the system Transfers from the meltdown vessel are now made after allowing a period for particulate material to settle
A stainless steel dip leg was used in the meltdown vessel during the melting of batch FS-105 in an attempt to avoid cracking of the dip leg The use of stairJlaquolaquo steel was liter concluded to be unsuitable because of the increased concentrations of iron and chromium observed in the resulting salt product The dip leg did not embrittle nor break during melting of the salt but extensive corrosion was noted on the submerged porshytion of the leg As a result of these observations a dip leg of copper and nickel was constructed by placing a copper sheath over a heavy-waD nickel tube The nickel tube provides rigidity and the copper is used both outshyside and inside of the nickel tube to obtain resistance to corrosion The copper sheaths are welded together at the lower end of the dip leg located in the meltdown vessel This combination of materials is expected to result in an increased dip leg life and less contamination of the product salt
An error was made in charging the ThF4 for batch FS-105 which resulted in salt that did not have the desired composition
922 Hydrofluorination and Hydrogen Redaction
After a salt batch has been melted in the meltdown vessel it is transferred at a temperature of about 750degC to the processing vessel where it is sparged with an HF-Hj mixture at a temperature of about 625degC for a period of about 10 hr The salt is then sparged with H 2
at 700degC the H 2 flow rate of 10 std litersmin used during the hydrofluorination step is continued for 30 lltr to reduce iron and nickel fluorides to their raquoraquopective metals
Progress of the hydrofluorination step is monitored by determining the HF content of the HF-Hj inlet and exit gas streams by absorption and titration of the HF in a metered volume of exit gas When the HF concenshytration of the inlet and exit streams becomes equal (or the concentration in the exit stream becomes slightly higher than that in the inlet stream) contact of the salt with the HF-Hj mixture is stopped A relatively low temperature about I00degC above the salt liquidiu temshyperature is used to minimize the rate of corrosion of equipment and to maximize the rate at which oxides are hydrofluorinated The hydrofluorination step is folshylowed by treatment of the salt with hydrogen at 700degC
to reduce iron and nickel fluorides The utilization of hydrogen during this step is low and large volumes of H are required Since the reduction reaction releases HF the concentration of HF in the off-gas stream is monitored and hydrogen treatment is stopped when the HF concentration reaches a low value (about 002 meqliter) and remains constant within the detection limits of the titration method
The total gas flows (H 2 and HF)during the processing operations are shown in Table 91 The values in the table reflect a steadily increasing quantity (from FS-101 to FS-105) of HF generated by H2 reduction of metallic fluorides that can be ascribed to a buildup of metals (largely iron and mcke) in the salt heels in the meltshydown vessel and in the processing vessel during operashytion These metals are converted to fluorides during hydrofluorination and thus add to the total quantity of metal fluoride to be reduced during hydrogen treatshyment
9 3 SUMMARY
The information presented in the previous sections indicates that the following factors are important in producing high-quality salt
1 Analyses of the raw materials indicate that there will be no concern with metallic contaminants unless metallic corrosion products are introduced during the salt purification or melting steps
2 The sequential buildup of metallic impurities in the salt produced in the I2-in-diam facility is the result of corrosion of the equipment This corrosion can be minimized by use of copper whenever possible when equipment is simultaneously exposed to salt and process gases Periodic hydrofluorination and discard of flush salt in the processing vessel should control any minor buildup of corrosion products
3 Although not demonstrated by data shown in this chapter it is believed that oxygen contamination can be held at low levels by maximizing the removal of moisture from the raw materials before they are melted and by improving control of the hydroshyfluorination process A method for measuring the H 0 produced by reaction of HF with oxides in the starting materials is being tested This should aid in determining the proper time at which to terminate contact of the salt with the HF-H2 mixture Alsoit may be necessary to determine the sulfur content of the off-gas since this may be the most difficult conshytaminant to remove from the salt
MOLTEN MLT REACTOR PROGRAM AUGUST lraquo4
i I MtfttitSI HHMHAM OIHH UgtM
m D M K M AMD M V I LOMMlaquo1 i n iH tGlL H
svsriMi AO AKAIVHI J N I N C U H
1 j A L L I N H
H 1 K | N lt I N
0 1 M A S M
0 I M I D N
ftWIMt A N C O f t M O M H T l M V I L O M N N I
m M G u laquo laquo O N H
A A H U - t U t l 1 M
W 0 H l V l M f t M N M 4 ft M l i l M H
m bull raquo | N S O N H 1 ftlOOLl N O t I R A V H I N M M bull H O raquo l raquo raquo S O N n
bull F A I M M O N M I M
4 M L V l l C L C M l M i S H V D i V t S i O N C M l W l t t N T D V I K O A j C M l W C A k F I C M A J O L O C J V 0 V gt V O V lt TACS A N D C A A W C S lgt iV traquo iC i M A C T O M ) O i V i S lt O N I X m v l f t S l T V O I I I N N t M I l
A t A H H I A U
M 1 M C O V MAC
M J U H U 0 Y N 1 T U W I I
H 1 I f c C O l MAC D N bull M lt S gt i MAC 1 M K h l S I A D MAC A k C L A J J I N C MAC I I J C X O U t t MAC
1 A U S T M A N G MAC
H l H I I I T A N t l MAC C A H V M A N M J laquo K t i t t H MAC
bull C U S U I MAC
bull M r N A M MAC 1 K R U C M I MAC A C t C M A f raquo M A U S ( H MAC i ft W O O t i S MAC
C M 4 M I C A L M K K I U 1 I M M A 1 I A I A L I
H M U I W V MAC
I I C H N I C A I t U W O I I t
A V HOI I M i MAC C 1 0 o N MAC n M raquo 4 H M t M - MAC 1 C k l l T N t H MAC J t I M i l H I H MAC I M l A r M l H L V MAC
J 1M H I N D I I C K S MAC T t M I N S O N MAC J 0 M ICWON - MAC
1 1 l A M H I X i 1 MAC
1 bullbull I I I MAC A ilaquo M i l l k H MAC (1 A gt 0 1 T1H MAC
I d H A H D O h MAC H H V I A M N O k MAC 1 i X M I M S K V H
tt I I S 1 I N I S MAC C K l i K l M A S MAC 1 H r H D I I I M MAC C A W A l l laquo ( l n 1 1 M K I C I H O I I S I MAC
M M gt H O C I t t l a O I V l l O r W I N I
J H Mt r HT ( )WraquoM IH bull
C M I M I C A l 0 I V I L 0 A M I N 1
A O fttk M l M S M H I I N M M
l O l N l l f t l laquo a O I V l l O H H N 1
gt H H I U H f O W I H JH C M SHOWN m n M c o i m c i c w t i bull H bull U N O A U l H M C S V A lt i
I B I A M S H O P A Y M
M M H C H I M I I T M V
l M M H H i S i A 1) r l L M I H S c L M A V A ( H t M t I C c raquo C A N T O N c I M l M c t O d i LPS T H I C K c raquo A r o i i raquo bull t H N M H O N k l U N t
D 1 H l A T H f R i V 1 O V A L l N l l N I c
A N A L Y T I C A L C H I M l t T N V
M M A A C H A f t O O I V I t O M M I N V
A I M f V I N AC H t A M | t bull AC B H C l A M K AC J M M A L I AC p L M A N N I N l t AC J P T f l U N t t AC
A N A l V S f l
i i I I M raquo I M At t it O o r t M - A l
ft ri i A i N t AC J A C A H I t l f AC
C O N S U L T A N T
r M A M A H t O V I I I
_ -L_ ULTMOOUCTION N M HtWIQN c bull I U A l t v C
bullH i AHVAK C I A c XJHNtOkt C t
Printed in the United States of America AnaiMMc from National Technical Inforniotion Service
US Deportment of Commerce 5286 Port Royal Road S o r - ^ Virynia 22161
Price Printed Copy SampSOMicrofche $225
I M V taporf laquopaw pranwas at an aocpaar a a w ajaaaaran a 001 latajaa aanai
Ada^unr0oon nor aft of ^bullJw onolovaaa tiar ooy of tfJaw connractors aabxonaaciors or insa anaaloapnv faonas an oaavrantv noorav o nooaoaV or
WBaransaaa fatrade bull P ^^raquo^aoo(r ajaww Rwgtgtraquo bullbullbull WMPCI a pr PEaa RK^PJWgt ar ranrfraquofmwww ttrnt I B uaf ajovaj not awKfaja prrtnjajh oamotf rtojm
U C 7 raquo -
CoMfKlMo
RMKMOO MMucrsiifii
LE
FENUAftY 1976
OAK RIDGE NATIONAL LABORATORY Oak R 4 T O T M H W 37W0
opwaNdby UNION CARMX CORPORATION
forffw ENERGY RESEARCH AND DEVELOPMENT ADMINISTRATION
MASTER V
~r -ruic rvVUMENT IS UNLIMITED WSTWBUTION OF THIS DucUWttrade ^
1 M Mpoct raquo olaquoc laquorf x laquornrraquo v4 IMA MIMA Weuro M C I MIO
i t a k trpoffe iHji AcwriM tnr ptoyrc bullgt the (aopun Ilihrgt c^wt i==v agt
0 laquo M 4 4 K M bMg 1 M V gt 31 Ilaquoraquo O K M - raquo tow (aMj CViltn 31 W ( K M X U total E M M J laquorgt 31 I OlaquoM raquo tow IKM laquolt gt-iraquo 0laquoM7raquo tonJtJMMfMgt3lllaquo5laquo ORMOSlaquo tnaikmtmtOctlt+tt HI (MSI m D m (tthnj teraquogt 3I JMI ii 30 |ltlaquo0 OKM-3QI4 tomJ fattMf Mgt 31 IlaquoMO ( K M 31 towi fawMf Frmgt gt Iltl OHM 321 lt towrftJMMf AMMM3I Ilaquoraquo OmSLi^Z total FMIMJ Hbrmay gt bull- ORM-334 tomt tJnf AMWlaquo 31Ilaquo ORM-34P to MOM Jmraquogt 311laquob3 0laquoL-35gt totaj tMJwf JMgt 31 IMJJ ORM-3raquogt towl EMM tani 31 fM O t M r rrd M Mgt 311laquoM OHM-3 I towJ to FVfrfwry 3gt bullbulllt OKM-sraquo total EMM laquo laquo i 31 Iltraquolt ORM-gt3b totaJ EMM F4MMgt gt IlaquoraquoM ORM-K~ to vlaquo MAM M J1Ilaquoferaquo G4LM4I J tow EMM i n laquo gt raquo I W OHM-raquobullraquo ftnud EarfMf Ailaquow4 3 bullraquo aM-raquolaquo4 toraquoi E M FlttNlaquoHgt i OHM4344 total EMJH Ktfmt 31 IltM OftM-ll towi EMJM FfMfgt gt Ilaquoraquoyenraquo ORM444 totaJEiMJ3llltraquo OfcM 444ft toml Eraquofc F4WlaquoM gt I OftM4j total b u b tmgmt 31 laquobull OftM467 feftal EMJM Flaquofcrmv bullraquo Ilaquo7l 0RM4gt total E n 31 I7| OftM47iC torn EMM Flaquoflaquoy -^ llaquoraquo OXM4K3 total EMM AapM 31 17 OftNL-5011 total EMM AMlt 31 I4 ORM-ttM towl E n FlaquoraMgt gt W
Coimnti
SUMAftY
PARTI mm KUCM Aim vcvujonmsj t v^SItMS AND ANALYSIS 2
raquo l n t t raquo bull ( bull bull laquo a Mete SJpound nam I I M 5 M C J U I M raquo 2 1 I r laquo 4 w t Srfl TlaquodMc4ap FMhn 3
I 2 amp w Rftowr raquo laquo sect bull 1 3 mroMi Aaalyws - 9
131 MSMSnrgt 9 l raquo TXr tCraquoo 12
14 t t^TcnpctsnMrDNpi I te fe 12
2 s m t J t S A X P C O I 0 9 ^ T S 0 m U gt r M L T 16 21 l t -Sgtnn TfdMofofy Fac 16
211 Crwraquomwiw4$rfihmdashySgttnOfcltjtiraquowi 16 2 12 S-ftowraquo^vfuiwHWif DWraquo3MCJamiilaquoirfVjnjWrnuwteimcraquogtn IS M M N ^ F laquo W M I F W 19 214 P w i mtmmiH 22
2 2 Claquo4aM-Sak T laquo f c raquo w F n iCSTFl 22 22 1 UvOMYJCM 22 2 2 M M M T M 23 223 TIMM Ei^tiMm 24
23 Ftwcrtf rlaquonlaquocimi Lon^sect 2 23 1 0prraquoiMigtfMSR-FCl-2raquo 26 231 DtwptmiCamnKnmafKVymtifCL 2
PART 2 IMLMSIRV
3 FUEL SALT CHEMISTRY 29 31 C n y i i i mttkt Lirtitmdashi Trfcinw Syami 29
3 Sprctrawoyy of Tcnprtan Sptctn n Manni Swu 30
3 3 Thr UrjMHMi TrirjIWori - H y d w y Ci|iiraquonmdashi m Matio Fhwnic SahMww 31
34 Fwam EJrctra S w laquo n laquo Mate Salts 32
35 Flaquo4 SafcladMi Sad lmnmttm Snafcn 34
36 Laiiior mamp FOWMHUH LJuMptcs of Fw-Ro TraMOc Meld Fbariafcs 37
ii i
IV
4 COOLANT SALT CHEMISTRY 4 4J ClKMtfiY ut SUAMW Ftourakcwa 41 4 2 CorrusmofStiuvinralAloysby Fmoroboraies 42
5 DEVELOPMENT ASD EVALUATION OF ANALYTICAL METHODS 44 51 m4aKAnafestraquo of Molten MSMtFnel 44 52 Tntmni A t f M Esperanents bull t Coutat-Salt Tedhnofagv Facnfcty 45 5J Ekctnlaquo^Kfic^Si^Maflralaquoll|aiMahaiLi -BeF -TM laquo
( T M 6 - i laquo ^ l 47 5 4 Vidummetnc Sankes of Tdnmnn m Molten LnT-BeF -ThT
lt2I6-I2 bull-gt 48
PAST 3 VUlERlAI^ DEVELOPMENT
6 DEVELOrMENT OF MODIFIED HASTELLOYN 52 61 DewelapinesM olt a Moitei Sait Test Fscdicy 52 62 rVocnmneai and Fabrication of Experjnental Almi 65
6-21 Production Heatsof 2 TiJIudrtied HasieRoy X 65 622 SltMfraquooictraquoltNi Keats of 2t TtModmcd H s N
Cammm Stdbmm 6raquo 6J WeMabiny afCanneTcni AlowgtModified HastetVn N 69 64 SUDdm of V m w Modified Hmrikn N Aloys m me
L nnf jdmed Condition 74 65 Mtdumcai Properties of Tiljmdashw Modified Hasietttn S Aloys
bull nW Umnndnied Condition 7 66 IVMirrsdnmn Creep Properties of Modified Kxuelloy N 82 6 7 Mkratntctwral Anah-raquos of Tnawm4lodified HastetVn N 84
671 MKroMracwnl Analysis of ABoy 503 and 114 85 672 HomopefctotisHastctoy S Aloys 88
6Jraquo Salt Corrosion Sindies 91 681 Flaquoe Silt Thermal Convection Lraquoraquops 93 682 Foci Soil Forced Circulation Loop 94 6 J raquo 3 CoolaMSalt Tfcennal ConvectionLoop 94
69 Corrosion of Hasaenm N and Otner Aloys m Steam 97 610 Observations of Reactions n M-talTeiliinum^i System 100 611 Operation of MetalTeHvnam-Salf Systems 101
6111 IHkumm Experimental put gtunVlt I 101 6112 Oironnnm Telunde Snfcmrfity Exprnmer 102 6113 Temjnwrt Experimental Pot Number 2 103
612 Gram tnawdary Embrittleinenl of Hasteiloy N by TeHuriwn 103 613 X-Ray Identification of Reaction Products of Hastetloy N
Exposed to Trikimm-CnnianMnit Eimromrents 107 614 MetaflografnW Exammatmo of Samples Exposed to
Telwnum-Canianwnii Environments 108 615 Examination of TeGcn-l P 119
6151 MeialopaphK Observations 123 6152 Chermcd Analyses for Temirium 124
V
fc16 Salt Prepantni aad Fad Fm Fafelaquo for TEGea-2 aad -3 131
7 FUEL PROCESSING MATERIALS DEVELOPMENT 132 71 SUCK CapMkTlaquob of Gfwhile with BoHMka^
bullKawm-Lrifcaaa SUMIMMK 132 7 2 Thermal Grlaquoaer Maraquo Transfer T laquo of Graph
maMofcMeaamLoap 133 T2I Wea^tChanan 133 722 Coaa^sttoaalCkaaats 133 f23 MkroMractwraiOnagri 137 7 24 DBcmsHN of Rente 37
PART 4 FUELPROCESSMC FOR MOLTEN-SALT REACTORS
a ENGINEERING DEVELOPMENT OF PROCESSING OPERATIONS 142 HI Metal TransferProcessDevelopment 142
111 Addrtion ltM Safe and turna Pka^ ir Metal Transfer Experanezi MTE 3R 143
12 R M d-l 144 a13 R raquo V 145 al 4 DrwwKM of Remits 145
a 2 Saftntoaiwir Contactor Dewdopmenr 147 H21 Lxpeirnents with a Mechanically Agitated Nnnitiprnwi Contactor
bull ike Sah-Ruamth Flowthronfi Facaify 14 a2 Evperiments with a Mrdumcafry Agrtatcd Vindiipri mi
omactor Una water and hVrcury 149 H3 Contavjoas Fhjonaator Devdopmert 152
a3 I histatbtion and Initial Operation of Autoresittance Heatmi Ten AHT4 152
a 3_ Drsam of aCoatamons Fuonaator Expenmeat Facdny iCFEFl 155 K33 Hmonme Disposal Sync for Md 7503 156 H4 Frozen WalCorrosion Protection Demonstration 156
a4 Fad Recnnstifation Enpneernt- Development 15 H41 Imtnaneniatton lor Anatynap Reaction Vessel Off-Gases 15a a42 Deng of the Second Fact Reconstitaoon Eapneermc
Experiment 160 85 Conceptual Deagn of a Mjlten-Salt Breeder Reactor Fad
Processing Engiaeermg Center 161
PART S SALT PRODUCTION
9 PRODUCTION OF FLUORIDE SALT MIXTURES FOR MSR PROGkAM RESEARCH AND DEVELOPMENT 163 91 Quantifies of Salt f-rodaced 163 92 Operating Experience in l2-m-diam Reactor 163
921 Charging and Mrfimg ltA Raw Materials 164 922 Hydrofluorination and Hydrogen Reduction 166
93 Summary 166
ORGANIZATION OIART - 167
PAST I h B M D E 5 raquo r a AND DEVELOPMENT
J REnael
I Srsvcavaad AmJrait
CaVnaatnms c4 the expected trnmm tcknor in refoessce-deagn MSMt a m loatmuid wall stmVcs of the uoanbte effects of ovale rams on heat ex chaff surfaces in the steam system and on surfaces exposed to the ccmaimmtm atmutawew The presence of oxide A n vjnraquoH laquoery km ptimubmty on the heat toaster surfaces would SMstnVaaey reduce the rate of intmm nwgrgrion to the steam system became of the mciemmg importance laquoltf the oxide-Am resistance at very km parshytial pre a w i of hydrogen and irnnaa l lowexi the reduction irom this effect alone would be rnuufficieut to heat rbe rate of tritiuui msginion to the steam system t J denied tames At rates ltd tritium irans-pori le the steam system the presence of oxuk-fam rcastatccs ltm loop wait tends to mcrease the rate of frinsra Hem mto the steam However tins effect a mukpufkaat at the low migiatiiw rates required
Potential ^inbwuonj of tritium m the ruotmt-Snh Technology Facmty were estimated for the cundrtmus o planned expenments In the absence of inborn rater-^ctioe with the salt other than mnpk ihisututici as ranch as laquoW5 of the added tnthaa cowU be expected to escape through the loop wals Removal of significant fractions in the loop off-fas coaM he expected uaH i the effective permeabmty of the loop watts were 10 to 100 times less than that of bare metal
Substantial chemical interaction of tritium with Nnaf 4-NaF was observed in the two tritium addition tests performed Ratios of cornbmrd-to-efcmnilal tritshyium in the salt inferred from elemental concentrations in the off-fas and combined concentrations m the sail were 50 and 530 for the two tests Approximately pound to of the dded tritium was removed in the off-gas stream prindpaly in a chermcaay combined water-soluble form
An undated aeutromes modrl raquot the lOOv-Mtftci releteace-dcsam MSMt r heme developed Muhi-duneanuaat mntagioap cakwUtmas wdi me the VENshyTURE code with newt run crosfsectson data dented catNcK from the fcNDF-IV Wwantv Pruoriune bull the croavteefMW dau was completed tor 3 otJraquo nachdo at lorn temperatures gtJt mtemi lot the planard cakvb-i m v Crow-stetson dau are also heme exammed it the two-step thenaai reaction Nangtr lt Naij i lrf winch is expected ilaquoraquo be the principal to sxe ot hebum m MSMt stractaral metals
A review of i he dau and cakubtsuns medio estauatc tdtunwe mveutories m the TeGen-l experMKM m-catesanuaccTtamtgt ltbull Xr
Work raquo contmaHNj raquo the udgt bullgt thrruul rotvh-ettmg and creep fafaw m react vtrwctural nuternh Analytical ractbodS are bemg developed which wdl be apphed Ss reference-design MSMt ilaquogt evaluate the significance of these processes m HattePoy N
The (ins-Systems TechnoVigy racdtty was ilaquoperated with water throughout the report ptnod Efforts to reduce the annua um ltH the salt-pump shaft oscdbtiom have been unsuccessful The jmyunudt of these oscdb-tions rs brgety dependent upon vk laquoi w ed so a bger-dhmeter imprler which wnl give the design flow and head at kmer speeds rs heme fabneated A method was developed for estimating the pump fountain flow Smce this flow was higher than desirable bach vanes wtl be used on the new rmpener o bnui the How Tests made at the loop indicate that the densnometer can be used to determine bubMe-sepiralar efficiencies if short-term tests are used
Routine operation _ltf the (oobnt-Satt Technology Facility was esiaMrshrd with more than 50Ghrof sah circidation without plugging in the loop off-gas Nne Measurements of the amount ot salt mist in the off-gas stream showed 100 to 500 ngcm iSTP) depending on
VII
1 M
w
l t
I BLANK PAGE
bull-laquo-
laquo t u
the a l t temprrataK and the I F flow rale MMO ike loop gas space The M M trap awtaard m the sah cold trap was effectn m meanta ike pm^mg hraquot had been expeneaxd earner Two i m i a marcoon lesti bullere coadacteJia whjch 85 aad bullraquo cwTi teaarvtwds of ifitmed bydropea ere added to the loop dame two I04raquo periods- Ficqaeat n i l aad off-gas sample were takea to mumlor the tRtaaa bebamor m the kwp
The torcedltoarctwa loop MSat-FCL-2b has accw-rautatcd MOO hi of oneratnaa with MSMl reference hart vdi at deaf ^ r coadmoas wrm riW expected low O M -roaoa rates Dbu oMaawd oa the beat master ckarac-terufacs of das sak air being aaafvard The deaga B eaeaadK complete for torced-coawectioa loops FCL-3 aad FCL-4 Coaaaoaeats ate beaaj fabricated J dec-tncal a i i f lHwia is proccediag
PART 2 C V E M S n t Y
3 Fari-MtCfceaaMry
Refachch pare Li Te lahoat lt oa a mole haasi bullas piipaatd by the coatroaedaddrooaof Kaaraaa to Hiaad hdnum The lac tam was began at 15QT bat afciamefjr tempt Mimes greater thja 50tTC acre reshyquired to complete the reactwa LiTe was prepared by rcactmg the aoidaomrtric amounts of LijTe aad tcfa-raan f o r brat 550^0
Apparatus for the spectroscopic stady of letunam species ia MSMt far salt has beta aaeaawed rYeima-nar work am hnmaa teshmars ia cbkmde taehs has shown ant at least two Mfbi-abjurbaig spears are present wirh uwapoatuai at the raja Li-Te to UTe Farthenaorc stadia with T e ia LiO-KCI eatectic have shown that laquo addition to Telaquo a lecoad species is present at high lemperatewH aador lag habie km activity
Apanxtm for the qtearoihotometric stady of the conawriam UFlaquo(dgt bull 4H 2 iggt = UFidgt bull HF|graquo has beea assembled aaa measurements using LiineF as the sointnt haw begaa A prehaaaary valac of aboat 10 was obtaiacd for the eqiaktiiam quotient at 6S0degC Tins vaiae is ia good agreement with the valat obtained pnwoady by other workers
Detopmeni proceeded on porous aad pact d-bed electrode systems as coatiaaoas on-line moailors of conceatralioas of declroactiwt species in molten sail solutions The packed-bed electrode of glassy carbon spheres was caNbralaquo4d using Cd 1 ions in LiCI-Kfl eutectk before experiments were conducted with B ions in solution The results of the experiments demon-straied the cpabdity of the electrode for momioring these and other ions
Preunaaary eiftrraacar i n c conducted iraquo cvatiaic watt ^wntkKM fetatmg to the naxmg bullbulllaquo VaBr - jF coutaai sah with M S M tiid vdi D F - f k f - H i r 4 F tMfc-ll ~-0S mute I Ibe result showed that ihr rate of erutatjoa oi BF gas raquoa naxau was low Mi vac of sanf amounts m coolant vdi wtth fael tab Jal bulllaquo result at the purctpttatam M aramam- ltlaquoc ibiwaaa-coataaaac -antpuands Vlt data w^re abtaaed +m ibr aaxaa M sanfl aaamats ot farl salt wwh o4aM vW( HesahstHeiprraataiiMi whvh a satal amtaai ot on-l aat salt cuataaaay igtxale was aaed with tael salt sae-eraed d m oude speoes aawe stable dun I O wlaquotc pMseat smce bullgtraquo pitecipitjnua of I O was raquodraquosrtraquool
A stads ul laztice eadadaKs ot tirst-ruw traassfiua-atrial (Wndcs was aadertakea to proadr a theraquofciicjl basts laquobullraquo ii itll Haw thrnancbrnacal data Urn uraLiaial metal tlaondes bratg obtaated from mm4 eitctrcisie gjiiaaJL ceKs I igaadnrid comctamsto pkxsul lattKe emhapy laquos ttnaat aamber for the rwraquoraquo senes CaF laquoo laFz raquo ScFgt to GaF mdkaied that dte staadad embdptes at loranfua plusmntf gtol N jad V F weilaquo saostaclors bat dial a m accante expcraaeatal lamn of Sit fur T i F V F O F CrF F e f aad FeF woald be deswabh
Analysrs tlaquot raaplr i ot coaJeasate coarcted danat opnaiwa of the Cooba SJ Tccbaolagy Facigt nahcate that the mpur aboar the gtali B aot a taaie mokvafar coeapoaad bat rather a auxtarc ot stamk gateows species sach as H 0 HF aad K F The coadtn-sate dtowed a intmm coaceatratioa ratio of aboat 10 rentiwe to dar salt Tha resak tajatsts a pinablc method for coaccatrafiag aad collectiag tntiam -a aa MSMl Related work showed that NaBF0H dnnohed ia ^ltobal sah uadergoes a reactwn that redaccs the OH ~ coaceatratioa m the salt prodacmg a mbtde frac-tkm Phyacal aad chemical obstrtalioas were made on the sysem VaF-NaBF-BjO at 400 lo oOtfC Work with compoaikms typical of ibe usual coulaat salt (oxide coaceatratioas up to 1000 ppm| showed that at least two oxygea-ooataaaag species are present One species n N a raquo F raquo 0 the other has not yet been bulldenirfied
Slddtes were continued o determine the extent lo which borides were formed in Hbstetoy N and btcoael 600 by reaction with NaBFlaquo-NaF at 640degC Data obshytained thus far indicate some formation of chromium and nickel borides however after four months of exshyposure of the alloy samples lo sal the boride concentra lion on the metal surfaces did not exceed 500 ppm in
I X
Haste X and 1000 pom m hwoaci MM) The tcvdh jhraquo dtuwei that A n mdash i n n these laquobullgtbullgtgt was setec-incigt gtraquodued by rhe salt
IkMb thrv period I I ~ ratio were oMMoted by laquogt4taaMneirv lechnnnsrgt in imu rhetmai-cunvecSoa loop and ltAC oiced-circgtdaraquooa loop Subie redox mo dnom H4MIHK bullbull exist m tbmnal-convrctiou loops U A ) 2V the I I ut9raquo raquo approximately T A IO ani respectively In forced-cunvectampn wop H I - gt she I I rlaquoraquolaquo n about copy Vraquo meinpfs feme et Keen ante laquobullgt reoxuJur the I i fhe melt by the addition ot mchet tiuundelaquolaquo some other oxidant
The results rora the fast series of tntnuu ldditmn experiments at the ( raquo u b n - U i Tcdmulugy Facem ltholaquo (wraquo ten tattle mimm exist m the off-gas m the ctesnental state the bwtli of tbe tntruei ltvwi at i iuai-huved laquo water-Mi Ale K m h appears thai about W of the uuecttd inmm experienced tvawticanf holdup raquo thr salt -and was eveutualy remmed m the system ott-
It was observed that the Fe - Fe electrode reacshytion n molten LraquoF-leF-ThFlaquo lt~2-l6-l2 mok i ckfseH approximates the soluble product case at a guid electrode the inwduMc product case at pyroiytic graphshyite and- deptwdmg on the temperature both soluble and insoluble product cases at an indium ekxtrode
Yoffarmarirw measurement were node m muMen liF-nVF -fhF 4 toSowute jddrtiuru tit Li Te is an effort to identify soluble etevitoactive lehurium species re the melt No soitammetnc evidence of such comshypounds was ohtaated These observations were m general agreement with cherracal analysis that indicated lt5 ppm Tern the salt
fAKfi MATEMALSKVF4j0PMtIVT
u Dtncfupmvnl bull bull MMuinJ lunumvy 3
Work raquo parfnHy complete on the molten-salt test facrlrty to he used mostly for mechanical property testshying Much lt (he test equipment is oprralmn
Alt products except the seamless tubing of the V-Ti modified HasteHoy N were received The first heat weighed lOjOOO Ih and had a fairty narrow working lem-prrature range- The second heat weighed WOO lb and had a wider winking temperature range Seamless lubing is being fabricated by two venders WeMahility studies
on these two beats showed bat their urldnsg d u n e lettstacs were euuwahm to those ut standard Hatfefoy V and thai extstmg wetdng procedures ut standard HaMcwoy could he used fur the y Ti Audited
The mechanical properties of HasteBoy gt inuiiaed wwh ifUnMtm nwhrum aad aiunuMun were evahaied m the undated and uwrradnted MB These piupertjcs were umd to estunate tfae mdwudwd and courtuntd wOBceMtauans of Manwani muhwun and ahnuuHnn reouwed laquou produce bntrte mienueuBK phases The tomnuuu ot brstrk phases m the aloy n i t mdash n muwuni was enhanced by an apphed stxss
SpeciBMns ot modihed HnseSoy were exposed to idlunuw from several dMterewi sources Tbe partial pressure tH tewynum above CrTelaquo at TOO C sMtm reasoatfjty dose to that anttcaujied tor MSMb Metal-lugraphic e-umnitiua o tbe exposed specuuens aite strauwnt revealed iblaquo aftoss coniauung OS to I Nb were resttfant to neTgnnular craefcrng by teiurrum
Further aaatysn ot the data lrlaquown TeGen-l showed that most ot the tdunum m each fuel p s was coircen-tafed on the tube wall The concentration bullraquo the salt was I ppm gtrr less The salt bssbcen preparew igtit gtugtng the fuel pur m TeGen-r and- and the puu tor Telaquoelaquo-- base been assembled tlte tuhng
t ipenments were contused laquobull-gt evaluate graphite as a matenal tor fuel prlaquolaquocrsssng apphcaimus The peneira-tmn ot graphite by buRtuth-utbimn suiutnms was found tigt increase with mcreasmg lithium concentration of the stdutKm and pore diameter of the graphite Decreasing the pore dBrneter or the graohae by pitch impregnation decreased the average depth of penetration However because fhe structure of the graphite was sarobie greaier-fhan-average penetration occurred m reginns bullraquo low density
A thermal-convection loop construcied 01 irkdyb-denum conumed ATJ graphite specimens in hot- and cold-let reports and circulated Bt 24 wt bullbull 141 at t Li for WOO hr at 700 C maximum temperature with a temperature differential of I00degC Very large wetghr mcrextes tJO to tgtT~ cccurted in ail ot the graphite samples primarily as a result of bhmuth intrusion into the open piMouty ot fhe graphite Disamclar-metal mass transfer bet weep molybdenum and graphite was also noted These results and previous capsule test results suggest that fhe presence of mofyhdenum enhances intrusion of bifrnuth-lithium solutions into graphite Thin carbon layers were noted on the molybdenum
X
PART 4 FUEL PROCESSING FOR MOLTEN-SALT REACTORS
8 EsgMecfMg Dcvdopraest of Piocessiwg Operations
Addition of the salt and bismuth solutions to the process vessels in metal transfer experiment MTE-3B was completed Two experiments were performed to measure the removal rate and overall mass transfer olaquofficients of neodymium In the first run about 13 of the neodymium originally added to the fuel salt (72-16-12 mole UF-BeF2-ThF4) in the fuel-salt resershyvoir was removed durine the 100 hr of continuous operation Overall mass transfer coefficients for neoshydymium across the three salt-bismuth interfaces were lower 1ian predicted by literature correlations but were comparable to results seen in experiment MTE-3
For the first 60 hr of the second experiment which was a repeat of the first experiment the rate of removal of wodymium was similar The second run was termishynated because of unexpected entrainment of the fuel salt into the lithium chloride in the contactor which resulted in depletion of the lithium from the fh-Li solushytion in the stripper and stopped further neodymium transfer
Future experiments in MTE-3B will depend on detershymining the reason for the unexpected entrainment of fluoride salt into the lithium chloride and it will be necessary to remove and replace the lithium chloride that is presently contaminated with fluoride salt
A hydrodynamic run intended to determine the effect of increased agitator speed on the extent of entrainme w OIK phux uw tne other in the salt-bismuth conshytactor was performed No visual evidence of gross enshytrainment was found Analytical results indicate that the bismuth concentration in the fluoride salt phase decreased with increasing agitator speed This unshyexpected result is probably due to sample contaminashytion
Development work continued on an electrochemical technique for measuring electrolyte film mass transfer coefficients in a nondispersing mechanically agitated contactor using an aqueous electrolyte solution and mercury to simulate molten salt and bismuth During this report period experiments with Fe-Fe2 were nude with improved experimental apparatus A stanshydard calomel electrode which enables measurement of the mercury surface potential was obtained Electronic filters were attached to the inputs on the xy plotter to damp out noise in the signal to the plotter Near the end of the report period a potentiostat was obtained which will automate the scan procedure now performed with
the dc power supply Copper iron and gold anodes hjve been tested The gold anode is the most satisfacshytory choice since it does not react with the electrolyte solution By noting that the active anode area in the cell could be decreased with no resulting change in the difshyfusion current it was determined that the mercury cathode rather than the gold anode is polarized Results indicate that the ferric iron is being reduced by some contaminant in the system Further tests with purified mercury and electrolytes in the absence of oxygen indishycate that the contaminant was present in the mercury Analytical results for Fe and Fe1 concentrations in the electrolyte phase are inconsistent with expected results Qualitative results indicate that a buffered quinone-hydroquinone system may be usefid as an altershynate to the Fe-Fe2 system
Installation of autoresbtance heating test AHT-4 in which molten salt will be circulated through an autoresistance-heatelt test vessel in the presence of a frozen-salt fim was completed and operation was begun A conceptual design was made of a continuous fluorinator experimental facility for the demonstration of fluorination in a vessel protected by a frozen-salt film Design was completed and installation was begun on a fluorine disposal system in Building 7503 using a vertical scrubber laquoith a circulating KOH solution Inshystallation was completed of equipment to demonstiate the effectiveness of a frozen-salt film as protection against fluorine corrosion in a molten-salt system
Off-gas streams from the reaction vessels in the fuel reconstitution engineering experiments will be conshytinuously analyzed with Gow-Mac galaquo density detectors To determine whether hydrogen back-diffusion in the cell body will be a problem during the analysis of the HF-Hj mixture from th hydrogenation column the cell was calibrated with NJ-HJ mixtures It was found that when the reference gas flow rate to the cell is suffishyciently high i effect of hydrogen back-diffusion is not seen The second engineering experiment will be conducted in equipment which is either gold plated or gold lined to eliminate or minimize effects resulting from equipment corrosion Several alternatives for gold lining or gold plating are discussed The factors which must be considered in deciding between lining or plating are listed
A design is being prepared to define the scope estishymated design and construction costs method of accomshyplishment and schedules for a proposed Molten-Salt Breeder Reactor Fuel Processing Engineering Center The proposed building will provide space for preparashytion and purification of salt mixtures for engineering experincnts up to the scale required for a 1000-MWfe)
l
MSBR and for laboratories maintenance areas and offices The estimated cost of the facility is SI5000000 authorization will be proposed for FY 1978
PARTS SALT PRODUCTION
9 Prodactioaof Flwnde Salt Mixtures for Research and Development
Activities during the report period fall in three categories (I) salt production (2) facility and equipshy
ment maintenance and modification and (3) peripheral areas that indwb preparation of transfer vessels and assistance to others in equipment cleanup
Salt produced in this period totaling about 600 kg was delivered in more than 30 different containers About one-half of the salt was produced in an 8-in-diam purification vessel and had acceptable purity levels The remaining salt was produced in the 12-in-diam purification vessel during five runs each of which involved about I SO kg of salt
Part 1 MSBR Design and Development JREnge
The overall objective of MSBR design and developshyment activities is to evolve a conceptual design for an MSBR with adequately demonstrated performance safety and economic characteristics that will make it attractive for commercial power generation and to deshyvelop the associated reactor and safety technology reshyquired for the detailed design construction and operashytion of such a system Since it is likely that commercial systems will be preceded by one or more intermediate-scale test and demonstration reactors these activities include the conceptual design and technology developshyment associated with the intermediate systems
Although no system design work is in progress the ORNL reference conceptual design is being used as a basis to further evaluate the technical characteristics and performance of large molten-salt systems Calculashytions are being made to characterize the behavior nd distribution of tritium in a large system and to identify potential methods for limiting tritium release to the environment These analytic studies are closely correshylated with the experimental work in engineering-scae facilities Studies were started in this reporiing period to reexamine the expected behavior of xenon in an MSBR This work will ultimately use information from experiments in the Gas-Systems Technology Facilitiy (GSTF) to further refine l 5Xe-poisoning projections and to help define the requirements for MSBR core graphite
I Molfen-Salt Reactor Program Staff Conceptual Design Study of a Single-Fluid Molten-Salt Breeder Reactor ORNL-4541 (June 1971)
Additional core neutronics calculations are being made for the reference MSBR using widely accepted evaluated nuclear data and a two-dimensional computashytional model These calculations will provide updated estimates of the nuclear performance as well as add -tional information on core characteristics Analogous methods and data are employed to provide support for in-reactor irradiation work
The GSTF is an engineering-scale loop to be used in the development of gas injection and gas stripping techshynology for molten-salt systems and for the study of xenon and tritium behavior and heat transfer in MSBR fuel salt The faciiitiy is being operated with water to measure loop and pump characteristics that will be reshyquired for the performance and analysis of developshymental tests with fuel salt
The Coolant-Salt Technology Facility is being opershyated routinely to study processes involving the MSBR reference-design coolant salt NaBF4-NaF eutectic Tests are in progress to evaluate the distribution and behavior of tritium in this system
Candidate MSBR structural materials are exposed to fuel sail at reference-design temperatures and temperashyture differences (704degC maximum nd i 39 aC lt17) and representative salt velocities in forced-convection loops to evaluate corrosion effects under various chemical conditions These operations which are principally in support of the materials development effort also proshyvide experience in the operation of molten-salt systems and data on the physical and chemical characteristics of the salt One loop MSR-FCL-2b which is made of standard Hastelloy N is in routine operation two others to be made of titanium-modified Hastelloy N are under construction
1
m BLANK PAGE
L Systems JR
11 TRITIUM BEHAVIOR IN MOLTEN-SALT SYSTEMS
Studies to elucidate the behavior of tritium in large molten-salt systems were continued in this reporting period Additional calculations were made for the IOOO-MW(egt reference-design MSBR to examine the effects that an oxide film on metal surfaces might have on the distribution of tritium Analysis of the informashytion being generated by the tritium addition experishyments in the Coolant-Salt Technology Facility (CSTF) was begun As additional data and results are developed they will be incorporated into the MSBR studies
I l l MSBRCakvbtioas
G T Mays
Calculations were performed to examine the potential effects on tritium transport to the steam system caused by the formation of oxide films on the steam side of the tubes in the steam raising equipment of an MSBR Th rate of diffusion of hydrogen (tritium) through metal oxides typically is proportional to the firs power of the hydrogen partial pressure in the gas phase as opposed to the i power for diffusion through metals (i-e the diffusion process is molecular rather than atomic) In addition at moderate hydrogen partial pressures the permeabiiity coefficients of the oxides may be as low or lower than those of pure metals Thus at the very low hydrogen partial pressures that would be expected in an MSBR oxide films could offer substantial resistance to hydrogen (tritium) permeation However the efficiency of such films would be limited by the degree of metal surface coverage that could be established and mainshytained during operation of the system
The computational model1 for studying tritium behavior at steady state provides for variation of the metal permeability coefficients of the steam-system tubes but assumes that diffusion through the tube walls varies only with the A power of hydrogen partial presshysure Variations in metal permeability were considered in previously reported results However the model also includes the effect of a mass transfer coefficient for tritium transport through a salt film inside the tubes Since transport through the salt film depends upon the first power of tritium concentration (or partial presshysure) this value was used to estimate the effects of oxide films Effective mass transfer coefficients were
Analysts
computed which included the resistances of the oxide films as well as those of the salt films1
Tritium distribution calculations were made for a variety of situations in which it was assumed that the effective permeabilities of the oxide coatings in the steam system were I 10 10~2and 10~3 times those of the bare metal at a hydrogen partial pressure of I torr (130 Pa) These results were compared with cases without oxide coatings in which the permeabilities of the bare metal were reduced by factors of 110 I0 2 and I0 3 The comparisons were made at three values of the UUgt ratio (10 2 10 and 0 4 ) and in all cases sorption of hydrogen or HF on core graphite was asshysumed to be negligible
The results (Table il) indicate that a low-permeability oxide coating would be more effective than a low permeability in the metal itself for limiting tritium transport to the steam system When an oxide film resistance equal to that of the metal was added the rate of tritium transport to the steam system was apshyproximately halved as would be expected (The total resistance to tritium transport was not doubled because of the contribution from the salt film) The results with a factor of 10 reduction in a steam-tube permeability due to oxide formation indicate that tritium transport to the steam system could be limited to the design objective of 2 Ciday However it may be unreasonable to expect to obtain and maintain oxide films of this quality in an operating system
Additional calculations were performed to investigate the effect of reduced permeability of the primary and secondary loop walls through the formation of oxide coatings These coatings can be expected to form in a manner similar to those expected on the steam equipshyment For a given steam-tube permeability reducing the permeabilities of the loop walls would be expected to increase the amount of tritium transported to the steam system With the reduced loop-wall permeabilities less
1 R B Brig A Method for Ctlculalmr thr Steady Sute Distribution of Tritium in a Molten-Salt Bre jet Reactor Kant ORNL-TM-4804 raquoApril 197)
2 G T May in MSR fmgram Semiamtii Progr Rep Feh 2 1975 ORNL-5W7 pp3 12
3 Although ihri calculalional approach assume thai the oxide film i located inside the tubes rather than outside it can be shown that for given oxide and metal permeaMifie this irrangement slightly overestimate the rate of hydrogen permeashytion through the wall
3
TaMe t l Effect of oxide Wmdash on uitmm i todeamtrttmatm MSUtlaquo
Rjti of oxrior raquolaquolaquo laquobull H inlw ltlaquo meial permnbiliiy Imdash 1 tieaw iytteraquo lOday I io nominal metal ratio 0 i d film Redaced meial
prmKabriiiy mvae tlaquobetr prrambibiy4
1 I 0 811 142$ 1 10 J 656 1169 1 10 115 203
10 10= 173 1351 10 bull 10 138 114 10 bull 10 23 198
10 ltf 19 662 10 I 0 J 16 575 10 10 3 142
10 gt w 2 93 10 10 15 84 10 10 lt 31
No wrption of H or HF on core paphtte At a hydropen partial prewurc of I ion
rWith nomnul meul permeability ^No oxide film
tritium would permeate through the loop walk into the primary and secondary system containments eliminashyting a potential sink for tritium A higher tritium conshycentration for partial pressure) in the secondary system would result creating an increased driving force for tritium transport to the steam system
The result of the calculations did indicate that with out the presence of a chemical getter in the secondary coolant more tritium was transported to the steam system when the primary- and secondary-loop wall pershymeabilities were reduced than in the same cases with reference permeabilities for loop wads However more importantly for those cases where tritium transport to the steam system had been reduced to the design-timi abjective of 2 Ciday through chemical additions of H HF or a chemical getter results showed essentially no increase over the 2-Gday rate Thus it appears that reduced loop-wall permeability hat little effect on tritshyium transport for cases where a tritium exchange mateshyrial is present in the secondary coolant
1 1 9 f^^a^af ^dgt T^haMwaflV frMsawv
J R fcneH G T Mays
A 1000-MWe) MSBR is expected lo generate about 2420 Ci of tritium per full-power day Calculations showed4 that unless a major fraction of this tritium
were converted to a chemical form less mobde than elemental HT the rate of migration of tritium through the metal walk of heat exchange surfaces to the steam system could be unacceptaMy high The purpose of the tritium addition experiments in the CSTF is to simulate the general conditions in the MSBR coolant-salt system to determine the extent to which tritium can be held up in the NaBFlaquo-NaF salt There is evidence that hydrogen-containing compounds in the salt may retain significant amounts of tritium
In the experiments the first two in a planned series tritiated hydrogen was diffused into the circulating salt through the walls of a hollow HasteUoy N tube The tritium could accamuiaie in the salt pas into the off-gas system or permeate through the metal walk of the loop to the ventilated loop enclosure Tritium concenshytrations were monitored in the salt and in the loop off-gas In the firlaquo =o experiments 85 and 97 mCi of tritium diffused through the HasteHoy N injection tube For a detailed description of the experimental condishytions see Sect 22
The computer program5 for calculating the expected tritium distribution in a 1000-MW(e) MSBR was modishyfied to describe the CSTF and was used to calculate potential tritium distributions for the experiments under the following assumptions
1 steady-state conditions 2 only dissolution of elemental tritium (hydrogen) in
the salt with no chemicai reaction witn the salt or any of its components
3 all transport through metal walk varies as the power of hydrogen partial pressure
Calculations were made for addition rates o( tritiated hydrogen equivalent to those achieved in the CSTF exshyperiments using assumed loop-wail permeabilities rangshying from the value expected for bare metal to 10 of that value The results (Table 12) show a significant effect of loop wall permeabiity on the fraction of the added material that could escape through the wafts This table also shows the calculated steady-state concentrashytions of elemental tritium in the salt (nCig) and in the off-gas (pCicm) in the same units that are being wed in reporting experimentally observed conjurations Abo shown are the inventories of elemental tritium in the loop walk that would be associated with the calcushylated transport rates through the wafts Since these cal-
4 G T Mar- m MSB fhjpmm Semhwrnu Prop Hep Feb raquo I97S ORNL-5047 pp J 12
i Hraquo bullltbull ami C W N M j r A Method ft e CtkuUting Ihe Sternly Sime DtttrHmitut of Tritium m t Molten Saft Krrrdrr Kemcior Uml 0RNLTM-UO4 (April 19751
Table 12 Calculated rieady-Male tritium diitrrbuliorw InCSTF foe experimental addition rale
Additi on rate Loop wall Tt ilia ted permeability mixture (fraction of hydrogen Tritium bare-metal Kmraquohigt tmCihr) value)
3 1 79 1 10 10 bull 10 bull
3 3 C 93 io-laquo 10 bull 10raquo
Time to reach 8Sf of steady-
state conditions (hrl
Fraction of addition rale which permeate
loop w-y (it
elemental tril removal in oil
turn r1Hraquo
Klvntental tritium Time to reach
8Sf of steady-state conditions
(hrl
Fraction of addition rale which permeate
loop w-y (it
Iraction of addition rate removed
CD Concentration
tpCicmi
concent ration in tlaquolt traquocigi
03 994 06 400 13 95 771 229 I5IKMI 50
38 149 851 55000 200 42 16 984 64000 2211
03 994 06 5(HI 17 103 7$-raquo 243 I90IJ0 (gt4 37 143 HS7 fi7000 230 42 I S 9S5 77tMM 26tl
Irtiium inventory
in metal walk Kti
01 oK 16 17
013 10 19 20
Sail and oil-gas concentrations only longer times required for steady-slate permeation through loop walls
0I tritium in hydrogen
01 I l tritium in hydrogen
t
s
oriatmas represeai steady-state coadmoiaad the nt-naa additioa experaaeats iavolwr t raaskats it a asefal to cuaader the taae renaaed to reach the steady state At high loop-wal penaeabihiies the coaceatratioas of ekaMRtal bullrtraai m the salt aad off-gas are low aad lead to -each steady vataes qakfcry for die additioa rales (see Table 12)- Soaiewhai toager u
aied arith lower assaned loop-wal ptrmdashnbiam hi al cases iidinaiiialjr I n a y times are niaawd to reach steady-stale rates of tiitiaai release throa|h the loop walls However this has little effect oa the triturate steady-stole levels ia the sail aad off-gas
Figures II aad 12 show the resatts of intiwm cua-ceairatioa raeasareaMau v the salt aad off-gas from
are reqaired to reach the higher coaceatratiaas assoo- the CSTF dariag the first aad secoad irilian addition
tn a m - M B laquo raquo
lO _ I 1 - bull ~~l 1 1 1 1 1 1 1 ^ 5 mdash
O SALT llaquoC | )
bull 0raquoT-laquoAS WATER SOLUBLE t$CiJtmh
A 0FF-euroAS ELEMENTAL (aCiar)
1 Mil
2 bull f
bull0
_ 5 n
poundL_ bull0
_ 5 n
mdash
bull mdash
mdash J jy^TRITIUM ADOlTlON bull mdash
2 2 bull II mdash
oraquo II ^ 10 G c
i s
pound 2 z tal Z I O
bull
0
bull bull
bull
A
bull bull bull
IIIIIJ 1 1
s 0
0 mdash
0 mdash
I 5 s
2
10deg
mdashb bull
e
a
e O
A A
A A
I 5 s
2
10deg A A aaw
i bull bull
s
2
bull -
bull i mdash
in- i 15 17 1raquo 21 23 25 27 29 Si
JULY OATCttTS
Fjj II Ofctcfvclaquo4 tnttvui cottt9MnHtottinCSTF 9ttn I
5
2
5
2 mdash
9
u 2 mdash
H = -S bull o u S 3
2 -
^ raquo mdash
5 h
2
bull0deg
raquo
2
mdash 1 1 1 1 1 1 1 1 = ~ O SALT (laquoCi l mdash bull 0FF-6ASVATCR SOLUBLE fcOA-i5) ^ mdash A OFF-CAS ELEMENTAL (f Citw5) mdash
^mm
a ^^ mdash^ 1 ltlaquo bull raquo I 1 1 4
^^ mdash 1 1
1 4 ~ trade
I bull mdash
bull
bull bull
I bull
I bull mdash I bull mdash
=
U
KITH KM A DOtT ON _
= bull
bull bull
llllll 1 1 1 1 V
bull
mdash
bullr T 0 ^
laquo bull 1 A A ~bull r^^ i S 0 O mdash mdash i S
A A ~~
0 0
e
51 A o = ^v 1 M M
mdash 4 A o-
mdash 1 -
bullbull i
T t If traquo bullraquo OATC MJtutT laquof7raquo
IT laquot 21
bull M M M ti cvrr MM i
7
tests The concentrations reported for the salt represent tritium in a chemically combined form since any eleshymental IfT trapped in the samples would have been reshyleased in preparing them for scintillation counting The tritium in the off-gis was present in two distinctly difshyferent cheriksl fonrr Part of the tritium activity was present in a water-soluble form implying a chemkil compound since HT does not interact significantly with water at room temperature The other form is presumed to be elemental HT since ft was trapped in water after passage of the sample stream through a bed of hot CuO
In all cases the results are presented in Figs 11 and 12 as reported with no corrections for apparent baseshyline concentrations However the results of samples taken before and after each test suggest that nonzero baseline concentrations were present The apparent baseline concentrations for the two experiments were
Itfexpcrineat Mcxatrineat
In uli 17 nCig I nCig In olT-cas elemental I pCicm1 I pOcm In off-jta water oiuMe I pCicm3 50 pCiere
During the tritium addition period for the first experishyment the tritium concentration in the salt (Fig I I open circles) increased almost linearly to a maximum of about 100 nCig and then decreased approximately exponentially over the following 3 to 4 days to its preshytest baseline concentration In the second experiment (Fig 12 open circles) the tritium concentration in the salt reached a maximum of 70 nCig and returned to the baseline concentration about 6 to 7 days later If baseshyline corrections are applied to the salt-sample data the apparent half-lives for tritium removal from the salt for the two experiments ar 92 and 12 hr respectively
If tritium removal from the salt is assumed to be a pure first-order process or combination of such procshyesses and if it is assumed that the processes were also active during the addition period the buildup of the tritium inventory in the salt (for a constant addition rate)should be described by
J M I O - i l l - bull ) X
where
V() tritium inventory in salt at any time I during che addition
A tritium addition rate
A lime constant for the removal process (or proc-esats)
I f several first-order processes were involved bull the intshyrant removal from the salt the time constant X would be the sum of the several individual time constants but the individual values would not be identifiable Substishytution of the actual addition rate into this equation gives the expected tritium inventory in the salt at any lime i f all of the tritium were reacting with the salt Conversely substitution of observed inventory values permits evaluation of the effective addition rate (the rate at which tritium did react with the salt) In either case the results may be expressed as ritium trapping efficiencies with values of 85 and 50 respectively for the two experiments These trapping efficiencies imply that significant quantities of the added material were reacting with and being trapped (at least temponriy) by the salt Data from the second experiment suggest the presence of other mechanisms with significantly longer time constants for removal of tritium from the salt Because of the apparent scatter in the data at longer times the extraction of these time constants was not attempted
The water-soluble tritium in the off-gas during the first experiment (Fig 11 closed circles) did not inshycrease significantly until after the injection was comshypleted and then rose to 1750 pCicm 3 The level then dropped rapidly to about 50 pCicm 3 rose again to about 300 pCicm 1 6S days after the addition and then decreased to lower values In the second experishyment the water-soluble tritium in the off-gas rose rapshyidly during the addition period and reached a maximum value at the end of the addition of 13100 pCicm 3 Abo the ratio of the concentration of water-soluble tritium in the off-gas to that of the elemental form was substantially greater in the second experiment than in the first
Owing to the apparent scatter in the data involving the water-soluble tritium in the off-gas for the first exshyperiment no quantitative evaluation was attempted However in the second test the initial decrease in conshycentration has an apparent half-life of 18 hr but the data again suggest the presence of other time constants An attempt was made to separate the time constants by assuming that the decay curve was made up A two simple first-order exponentials This led to apparent half-km of 9 J and 37 hr for the two processes Numershyical integration of the water-soluble tritium data for the second experiment yielded a total flow of 58 mCi through the off-gas line during the removal period and 75 mCi during the addition period Thus a total of 65 mti or about 65 of the tritium added is accounted for as combined tritium in the off-gas stream during this test Since the concentration of elemental tritium was
8
always less than 001 of the combined tritium concenshytration the presence of any elemental tritium does not significantly affect this observation
The concentration of elemental tritium in the off-gas samples rose during the addition phase of each experishyment 2nd apparently began to decrease as soon as the addition was stopped The maximum concentration in the first test was about 800 pCicm3 and only 40 pCicmJ in the second In both cases the decrease in concentration with time after the addition was too irregular to justify any quantitative evaluation
Although no measure of elemental tritium concentrashytion in the oalt a available a value can be inferred from the concentration in the off-gas by (1) assuming that the elemental tritium in the off-gas samples represents release from the salt and only from the salt and (2) assigning reasonable values to gas stripping parameters in the CSTF pump tank Concentrations of eiementai tritium calculated in this way indicate that the ratios of combinedelemental tritium in the salt were about 50 and 530 in the first and second experiments respecshytively It appears that chemical interactions between the tritium-containitg compound in the off-gas and the new metal of the sample line may have been responsible for the high concentrations of eiementai tritium in he off-gas samples from the first test and that the actual ratio of combinedelemental tritium in the salt may have been higher than 50
The inferred maximum concentration of elemental tritium in the salt during the second experiment is about 013 nCig Extension of the calculated tritium distribution with nominal metal-wall permeability (Table 12) to lower concentrations indicates that at 013 nCig tritium permeation through the loop walls could account for no more than about one-third of the tritium added to the system Since this is close to the amount not accounted for in the off-gas samples it appears that the effective permeability of the loop walls is near that of bare metal
12 XENON BEHAVIOR IN THE MSBR
GTMays
The computer program MSRXEP Woden-tali Rate-tot Xenon Poisoning) describing the X e behavior in the reference-design MSBR was used to perform calculashytions to study the effects of the Knudsen diffusion coefshyficient for xenon in the bulk graphite and graphite coatshying of the reactor core on the X e poison fraction The program has been described previously bull7
Following the fission of the fuel the decay of the mass-135 fission fragments is assumed to follow the decav chain shown below
l l
5 X e (1529 mm)
135 s C i J 135
(659 hr) Ba
(30 X 10 yr) (stable)
This diagram illustrates the half-life of each isotope and the branching ratio of the 3 5 1 decaying to 5 m X e and l 3 5 X e assumed for this study Along with this decay chain the following input data were used
Bubble concentration 44 bubbles per cubic centimeter of salt
Total helium dissolved in salt and present in gas bubshybles 10 X 10 molecm3
Bubble separator efficiency 907
For these conditions the mass transfer correlation in the program gives a bubble mass transfer coefficient of 00166 cmsec which leads to a loop-averaged void fracshytion of 055 with an average bubble diameter of 065 mm The calculated 3 f Xe poison fraction is 00046
The reference Knudsen diffusion coefficients for the bulk graphite and graphite coating associated with the 00046 poison fraction are 238 X 10 and 258 X 10 cm2sec respectively The bulk graphite values were varied from 258 X 10 to 258 X 10 cm1sec assuming no graphite coating was present (Table 13 cases I 3 5 7) to observe the effect on the poison fraction The low-permeability graphite coaling - 028 mm thick was assigned bulk-graphite values for the Knudsen diffusion coefficient and porosity making the coating part of the bulk graphite for calculation purshyposes Under these conditions the porosity of the bulk graphite was held constant at a value about 31 times
bullThe complete units for diffusion coefficient arc (cm ps) (sec bull cm graphite)
6 H A McLain el al in MSR Pmgrmn Semttmu front Rep Aug 31 1972 ORNM832pp If 13
7 H A McLam et at in MSR fmpwm Stmiumu Prop Rep Feb 29 1972 ORNL-47K2 pp |3 16 17
9
Kmfara M i a s m cocflkatat l c raquo p v laquo c -en graphite) CakabKlaquo1 Xe
DOHOB fractna M k f r a p a i K Graphite coati
CakabKlaquo1 Xe DOHOB fractna
1 258 x 10 Socoanag 00153 2 258 x 10 258 x 10 bull O0J52
3 258 x 10 No CiOMg 00140 4 258 x 10 bull 258 x 10 7 00I4S
5 258 x 10 bull Nocoatne 00113 258 x 10 bull 258 x 10 00107
7 258 x 10 No coalBaj 00077 8 258 x to bull 258 x 10 c 00044
M t graphite porosity ralae RKMH COHSUHI in ail cam 31 t met greater than rhe valar for ike graphite coating Refereraquoce valar for Hrfk graphite r Reference laquoalac for graphite coanag forma fraction for reference case
greater than that of the graphite coating In addition the Knudsen diffusion coefficient for the graphite coatshying was varied within the same aforementioned range while the diffusion coefficient of the bulk graphite was held constant at its reference value oi 258 X 10 cm 2sec to observe the effects on the poison fraction (cases 2 4 6 81 The previously stated values involving bubble characteristics and mass transfer were held conshystant throughout this series oi cakulalions
The results (Table I J | indicate that Knudsen diffushysion coefficient for the bulk graphite and graphite coalshying at least as low as the reference values (258 X 10 and 258 X 10 cm 1 sec ie case 8) would be reshyquired to meet the 0005 target value I gtr the X e poison fraction A diffusion coefficient of less than 258 X 10 cm 2sec would be required for the bulk graphshyite with no coaling became of its higher porosity If the permeability of the graphite coating did not yield a difshyfusion coefficient equal to that of the reference value such a coating would have little effect ltgtn xenon poisonshying The penalty for not coaling ihe graphite iraquo about OX)I in xenon poison fraction or 001 in breeding ratio if no attempt is nude to decrease the permeability or porosity of ihe base material
It may be noted in case 3 that a slight reduction in the Knudsen diffusion coefficient for ihe bulk graphite is
more effective in reducing the 5 X e poison fraction than a simitar reduction in the Knudsen diffusion coeffishycient for the graphite coating in case 4 In cases 6 and 8 where the permeability of the coating is very low reshyducing the Knudstn diffusion coefficient for the graphshyite coating affects the 5 X e poison fraction much more strongly
1 3 NEUTRON ANALYSIS
H T Kerr D 1_ Reed E J Allen
The neutronic analysis work during this reporting period has involved several tasks aimed at additional description of the neutronic characteristics of an MSBR and the provision of ncutronics information for the fueled in-reactor irradiation experiments
I JI MSIX Studies
Neutronic analysis studies for the reference-design MSBR are in progress in three areas
1 development of a two-dimensional neutronic comshyputational model of the MSBR using the computer code VENTURE and reestablishing the operabiliiy of a reactor optimization code (RODI
2 updating the neutron cross-section data bast used by various computer programs
3 calculation of the rate at which helium wii be proshyduced in the reactor vessel of the MSBR
A neutronic computational model o( Ihe MSBR using the computer code VENshyTURE is being developed VENTURE is a multishydimensional multigroup neutron diffusion computer code The MSBR model will have nine neutron energy groups and the ir-z geometry shown in Fig I J The various zones in the model allow for different core comshypositions and cress-section sets In addition to providing a check oi the design studies made with the ROD code using one-dimensional calculations this model will pershymit explicit evaluation of the nuclear reactivity effects associated with localized core periurbatiuii ltch as limited core voiding Previously such effects were conshyservatively estimated from calculations for an infinite medium of salt and graphite
bullhr pneffcv tuuHaniial reducifcMt in da Kmudm aWuaioa owflfcieat probatory wouhl be accompjaml by reduced po-roaiy
I T B r- ter 0 R Voady and G W ( unnmfham III irTlKf A CoaV mock for Sotriig Htipaup Stummk-ProNtwt Applying the Finite-Difference DiffmkmPieorv Appnaimntkm to Seutron Trmnpprt ORNL-SOamp2 tOvtohet 175raquo
9 II r Ramnann el al HOD A Sudew (md Fuel Cycle ImfSt-Mi Code for CmuUlmtFuel Rewclon ORNL-TM-3JS9
l September I 711
10
79-m7S
-a r
a-7
PERCENT THICKNESS 1 cm) ZONE NO FUEL SALT RADIAL AXIAL
1 CONTROL ROOS 172 2195 2 CORE )A 132 32 a 2195 3 CORE I A 132 500 2195 4 CORE I B 132 1195 2195 5 CORE n A ANO B 370 381 254 bull 9lR)^bV ^ W ^ ^ V v 1000 51 51 7 GRAPHITE REFL 10 7S2 aio bull SALT ANNULUS 1000 oa oa 9 REACTOR VESSEL 51 51
Fk 1 J Tw MMMH^OMI coMf bulltMtoMiMoMorNsm
11
ROD is a computer prccram for nuclear and fuel-cycle analyses of circulating-fuel reactors It consists essenshytially of a neutronks subprogram an equuibrium-conceniration subprogram and an optimization subproshygram Variables uch as breeding ratio fuel composition etc can be optimized with respect to cost
The operational status of the ROD code has been reshyestablished by running a telaquo case for the reference-design IOOO-MW(e) MSBR using the old cross-section data previously generated for the MSR program The test case will be rerun using the ENDFB-IV cross secshytions and any significant differences will be evaluated and reported
Generation of bullposted cross section data The necesshysary descriptive information for the neutronic model for use in the computer code VENTURE has been colshylected and the most recent ENDF1 cross-section data are needed (The neutron cross-section data used for MSBR analysis were originally derived from the GAM-H and ENDFB-I libraries with some ORNL modificashytions1 and no recent updates have been made) The new cross-section data are being obtained exclusively from the ENDFB-IV data Tiles using the AMPX processing system This effort will provide evaluated cross-section data and neutron energy spectra for typical regions of an MSBR and will serve as the data base for subsequent MSBR nuclear analyses The steps involved in this process are
1 Calculate 123-neutron-energy-group cross sections from the ENDFB-IV library The ENDF point data for 39 nuclides are weighted over an assumed energy spectrum to derive mulfigroup cross sections Thermal scattering cross sections are treated at 300 600900 and 1200 K for each nudide
2 Determine contributions to the multgroup cross secshytions from resolved resonances resonance self-shielding is treated for the various fuel configurashytions at 900 K
3 Perform fuel-moderator cell calculations for four geometries to adjust the cross sections for the flux depressions in regions having a high concentration of fuel or moderator (ceD homogenization calculashytions)
10 ENDFB-IV is ihe Evaluated Nuclear Data File-Vcnion IV and is the national reference set of evaluated cross-section data
11 O L SmithPreparation of 123 Group Matter Ctwt Secshytion Library for MSR Calculation ORNL-TM-4066 (March 1973)
12 N M Crane et al AMPX A Modular Code System for Generating Coupled Muttipoup Neutron-Gamma Ubraries from ENDFIB ORNL-TM-3706 J1974)
4 Perform a one-dunemional neutron transport calcushylation of the MSBR core to determine 123-group spectra and collapse the 123-group cross-section set to nine groups for each of the various zones in the model
5 Reorder the nine-group set from nudide ordering to group ordering the cross sections are then ready for use in VENTURE and ROD
The initial processing step is capable of treating nuclides in groups of from 1 to 3 depending upon the amount of data in the ENDFB-IV file for each nuclide This step is now complete for aD the nuclides of interest except 2 T h
Heauaa production bull reactor vessel The helium proshyduction in the reactor vessel for the present reference design and possible alternate designs will be estimated in conjunction with the neutronic modeling of the MSBR (Neutron energy spectra and flux magnitudes in the reactor vessel as obtained from the neutronic modd provide the bass for calculating helium production rates)
Helium is produced in nickel-base alloys primarily from these reactions
raquoNi raquo gt raquoNi raquo gt 5 Fe + 4 He
N i ^ L _ raquo F e laquo H e
degNi gt i 7 F e r 4 H e
The sNi(njt)and the degNi(ija) reactions are induced only by high-energy neutrons whereas the 5Ni(n7raquo and 5 Ni(laquoa) reactions are induced primarily by low-energy neutrons In highly thermalized neutron energy spectra as in the MSBR vessd the two-step reaction 5Ni(n7) $Ni(ffa) is the principal source of helium The 5 Ni cross sections are not wdl known but differshyential measurements are being made by ENDF particishypants1 Abo hdium analyses are available from several irradiated nickd specimens and effective integral cross sections wii be derived from these data for comparisons with the measured cross sections
At presen some cross-section information is available for the NHHJO) reaction Values for the 2200-msec (ix 00253-eV) cross section have been reported as 137 barns 4 and 18 barns It has also been reshyported1 3 that a large resonance occurs at 2039 cV with a total width V of 139 eV From this information a preliminary estimate of the shape and magnitude oi the
13 F C ferry Report to the US Sutiear Data Committee ORNL-TM-4SS5 (April 1975)
14 H M Eibnd el al Hud Sri poundltty 5) I I January 1974
12
cross section can be deduced and 123-group cross secshytions generated
From the Breit-Wigner one-level formula
where
A = constant A = neutron energy
tr = resonance energy (2039 cV) = total width (139 eV)
The constant K can be determined from the value of the cross section at 00253 eV which for this study is assumed to be either 137 or 18 hams Energy-dependent cross sections can be generated and the helium production can then be estimated with te folshylowing equation
-V H eltraquolraquoraquoraquoilaquoraquoJ - bull bull )
X 1 - e x p ( - o e 0 1 o
- [I exp ( -OJ IDI OJ I
where o ( = (17) cross section of s Ni Oj = absorption cross section of s N i Oj = (na) cross section of N i A1 - initial s N i concentration
9 = neutron flux = time
V|| e(0 = helium concentration at time t
IJ2 Analysis of TeGenE-r-raquoiments
Fission rates and tellurium production rates for the fuel pins in the TeCen-l irradiation experiment were reported in the preceding MSR semiannual report The fission rates were estimated by a flux mapping experiment direct flux monitoring of the TeGen-l capshysule and computations analyses The tellurium concenshytrations in the fuel pins were calculated from these fisshysion rates but no estimates for the accuracy of the calculated tellurium concentrations were given in the report
The accuracy of the 2 3 U fission product yield data 1 6 leads to an estimated uncertainty for the yield of tellurium in the TeGen-l capsule of about 135 Assuming that the uncertainty in the estimated fission rates is plusmn15 the uncertainly in the reported tellurium concentrations is about 20
The TeGen-2 experimental capsule is scheduled to be inserted nto the ORR for irradiation in October I97S Flux monitors will be loaded into the capsule prior to the capsules insertion into the ORR After the TeGen-2 capsule is removed from the reactor the monitors will be recovered and their induced activities measured to develop estimates of the tellurium production rates for TeGen-2
14 HIGH-TEMPERATURE DESIGN METHODS
GTYahr
Thermal ratchetttng and creep-fatigue damage are important considerations in the structural design of high-temperature reactor systems Simplified analytical methods in ASME Code Case IS92 (ref 17) and RDT Standard F9-4T (ref 18) permit the assessment of ratchetting and creep-fatigue damage on the basis of elastic-analysis results provided 1 number of restrictive conditions are met Otherwise detailed inelastic analyshyses which are usually quite expensive for the conditions where they are currently necessary are required to show that code requirements are iet Analytical investishygations to extend the range over which simplified ratchshyetting and creep-fatigue rules may be used to show compliance with code requirements are being performed under the ORNL High-Temperature Structural Design Program which is supported in part by the MSRP Modeling procedures for applying the simplified ratchet-ting rules to geometries and loadings prototypic of those encountered in LMFBR component designs are to be identified Then trie conservative applicability of these ratcnetting rules and procedures and of elastic creep-fatigue rules will be demonstrated and placed on a reasonably sound and defensible engineering basis Finally an assessment will be made of the applicability of the simplified design methods to Hasteiloy N under MSBK design conditions and the importance of thermal ratchetling in an MSBR will be determined
S II T Kerr and F J Allen in MSR Program Semiannu Pnrfr Rep Feb A 1975 ORNL-5047pp M 15
16 M F Meek and B F Rider Compilation of Fission Product Yields Vallecilos Suclear Onter 1974 General Elec-ric Company NFDO-I2I54-I (January 26 1974)
17 Code Caw 1592 Interpretations of ASMF Boiler and Prejre Vessel Ctde American Society ltbull( Mechanical Fni-neerv New York 1974
18 KDT Standard F9-4T Requirements flt Construction of Suclear System Components at Elevated Temperatures (Suppleshyment to ASMF Code Cases I$92 1593 1594 1595 and I5VA) September 1974
13
The detailed plans for achieving the stated objectives were given in a previous progress report The basic approach is to perform a relatively small number of carefully planned and coordinated rigorous dastic-plastic-creep ratchetting-type analyses of the geometries illustrated in Fig 14 Each geometry is subjected to the axial bending thermal transient and pressure loadings described in Table 131 of ref 19 Structural problems I and 2 are being analyzed at ORNL using the PLACRE computer program 2 0 while problems 3 and 4 are being analyzed by Atomics International and Comshybustion Engineering respectively using the MARC comshyputer program1 Each inelastic analysis will include a complete code evaluation for accumulated strains and creep-fatigue damage Also ssociated with each inshy
elastic analysis are a number of elastic analyses to proshyvide the input parameters required to apply the various simplified ratchetting rules and procedures and elastic creep-fatigue noes The progress to date on these studies is discussed below
Both Al and CE have encountered difficulties in their three-dimensional inelastic analyses Although consider-
19 J M Comm and G T Yabr in MSR Program Semmtmu Progr Rep Feb 28 1975 ORNL-5047 pp 15-22
20 W K Saitory Fiirte Element Pnfnm Documentashytion High-Tempertnre Sintctmwl DrsnM Methods for LMFBR Components Quart Prop Rep Dec SI 1971 ORNL-TM-3736 p 66
21 MARC-CDC developed by MARC Analysis Research Corporation Providence Rl
-YV^ - NOTOCD CTLMMCM SHELLS TYPE 3 N0ZZLE-1D-9PHQMN
OftNl OWC 75 76S
SMELL
JUNCTION OETAS (TYPES 341
76i0 X ilaquo75 WML
TYPE 2- cnjomctL awns
Q-omdash -T-QlaquoO -Q0
) AT AT I (bull) STEPPED MMLTHKKNESS (k) UNFClaquoM WILL WTH
OFFERENTUL MTOCTTNG
TYPE 4- nomz-m-crurvmcM SHELL flHXMLET NOZZLE)
1 6 0 0 X0375 WALL
-TS IO X 1675 WALL
(O IMFODM VMU MTH (ABULT-M CYUNOEP AXIAL TEMPERATl J VWaATCN
Fij 14 Slnicturai crmfiguraiinns used in the analytical invatqplion of the applicability of simplified nlchetling and crrcp-faligiie rule
14
able effort has gone into developing fmite-elemeni models that are of a size that can be accommodated on presrnt-day computers and into improving the MARC computer program the large 3-D inelastic analyses are proving considerably more expensive to run than had been expected
The experience at AI and CE indicates the importance of developing amplified methods of analysis Three-dimensional inelastic analysis of many realistic comshyponent geometries is too expensive and time consuming at present to be used routinely Although developments in computers and stress analysis programs may bring the cost down in the future it is desirable meanwhile to mminuze die number of inelastic analyses that must be done
141 GrcutarCyundricai Shells
Nine cases of circular cylindrical shells luve been proshyposed for bulllaquo present study Two of the cases involve notched shells The other seven cases involve axial variashytions in temperature pressure andor wall thickness or a bunt-in wall All nine cases were to be analyzed using the ORNL in-house finite-element program PLACRE
A ten-cyde inelastic analysis and a one-cycle elastic analyras have now been completed for all nine cases Both thr inelastic and the elastic results for all nine cases have been completely poKprocessed
Because of modifications to the creep-fatigue damage rules presently under study by the ASME Boiler and Pressure Vessel Code Working Group on CreepFatigue it may be necessary to modify the ORNL postprocessor and repeal some of the postprocessing to keep the present study up to date
142 Nozzle-to-Spherical Sfcenf
After some difficulties the MARC computer code a operational on the IBM computer at the Rockwell Intershynational Western Computing Center and check cases have demonstrated that this code will perform satisfacshytorily
Considerable effort has gone into developing the finite-element model of the nozzle-to-sphcricai shell An isoparametric three-dimensional 20-node brick eleshyment will be used (o model the entire geometry Beshycause of symmetry about the plane of the applied moment only half of the nozzle-to-spherical shel has to be modeled There are raquoix 30deg-wide dements around
bullWork jlt ORNL by W K Sartory Work raquobull Atomics International by Y S Pn
the half-model There are three elements through the wall at the root section of the nozzle and only one element through the wall in both the nozzle and the sphere away from the intersection region
A series of elastic analyses must be done since this is a thermal stress problem in which temperature varies with time Since the moment applied to the nozzL is the only nonaxtsymmetric load the principle of supershyposition will be used to reduce the cost of the elastic analyses A series of axisymmetrk analyses were done to determine the stresses due to the internal pressure and temperature and one three-dimensional analysis was done to determine the stresses due to the moment applied to the nozzle The stresses from the three-dimensional analysis will be added to the stresses from the axisymmetric analyses to obtain the total elastic stresses
The axisymmetric model in the elastic analyses was used to determine what maximum thermal load increshyment may be employed without having to do an excesshysive number of iterations during each increment On this basis the first ryele of the three-dimensional inelastic analysis was divided into 32 increments The first three increments of the three-dimensional inelastic analysis have been completed The computer cost for these three increments was higher than anticipated Efforts wiQ be made to find some way to reduce the cost to an acceptshyable level
14J Nozzte-toCyindeT Intersection
The original concept for the inelastic ratchet ting-type analysis of the nozzle-to-cylinder intersection was to perform two separate analyses (I) a thin-shell analysis of the whole structure ami (2) a detailed three-dimensional solid analysis of the intersection only Disshyplacements and forces to be applied at the boundaries of the three-dimensional solid model of the intersection were to be determined from the shell model at the end of each loading increment The total computer time of the two analyses would be less than that required for the solution of the problem using one model of the complete nozzle-to-cylinder intersection with suffishyciently small elements in the intersection region Howshyever the transfer of the forces and deflections from the shell analysis to the three-dimensional solid analysis was found to be more difficult than anticipated Because the shell element and solid element have differtit displaceshyment functions a special constraint must be imposed on the shell elements at the boundaries of the three-dimensional solid model to assure compatibility This
bullWork at Combustion Engineering by R S Barsoum
15
stiffens the intersection in the shell model When runshyning the initial elastic analyses it was found that small changes in the displacement boundary conditions applied to the solid model would produce large changes in the results of the analysis- From a pragmatic viewshypoint the biggest difficulty with the two-model method is assuring that the correct data are transferred from the shell analysis to the solid analysis at every increment in loading
Due to the above considerations it was decided to do the analysis by using only one model made up of a combination of a reduced integration shell element and a 20-node solid element which are fully compatible with each other
It was necessary to restructure a large portion of the MARC program to perform the inelastic analysis for the
3-D nvdel of the nozzle-to-cylinder intersection This restructuring made a larger core available for the analyshys t The restructuring involved stripping unnccded porshytions of the program putting common space on low-cost storage and eliminating mesh optimization and its correspondence table
The inelastic analysis of the nozzle-to-cylinder intershysection was started The full pressure and nozzle-moment loadings were imposed on the structure which resulted in stresses less than 0936 of the yield stress at 870 K ( I 00degF) When the first increment of thermal load was applied convergence was not obtained because of an error in the computer program which is being corrected
2 Systems and Components Development R H Guymon
21 GASSYSTEMS TECHNOLOGY FACILITY
RHGugtmon GTMays
After a brief shutdown at the beginning of this repottshying period to modify running clearances in the pan water operation of the Gas-Systems Technology Faculty (GSTF) was resumed on March II 1975 with the bypass loop blanked (Fig 21 gt Considerably larger salt-pump shaft oscmatious were encountered than before the labyrinth clearances were increased1 After obtainshying calibration data for the main-loop variable-flow reshystricts and for the salt pump at low flows the ioor was shut down to install the bypass loop variable-flow re-slrictor Water testing was then resumed on April 14 and continued throughout the period
Data for calibration on the bypass loop variable-flow rcstrictor and for the salt pump were obtained At normal pump speed the head-capacity performance of the installed imprDer was v W below the nominal loop design conditions At the nominal liquid flow rate and pressure drop in the main loop the flow rates from the gas outlets of the bubble separator were satisfactory Although loop cavitation (as indicated by wise level) was reduced by replacing the variable-flow restrictors with orifices the amplitude of the salt-pump shaft oscilshylations was not reduced appreciably Prdirmnary infor-
I R H Gaymoa MJ V R Haadty JUSK ABVW Stmt-mm Anjr Rep Feb 291975 ORKL-507pp 23 25
shows that leakage past the salt-pump shaft labyrinth is higher than desirable and attempts wfti be made to reduce thts
Tests under actual operating conditions with water in the loop indicated that the densitometer war be sttsfac-tory for salt operation IVelinwuary information obshytained fiom saturating the loop water with air and then stripping the air by injecting hehum at the bubble genershyator indicated the need for moniioring the oxygen conshycentration in the off-gas from the bunt salt separator in the off-gas from the salt pump in the loop water and perhaps in the water in the pump tank Dtitkuhies were also encountered with the response lime of the oxygen monitors and with the reprodudbiity of their readings
Data on the salt-pump shaft deflections and oscara-tions obtained during the previous period indicated that the running clearances at the labyrinth (fountain flow area I and at the impeuer hub should be increased to prevent contact of the metal surfaces during operashytion with salt (Fig 22) After increasing the clearances water operation was restarted with the bypass loop Hanked off The shaft oscillations were much larger than they had been previously under similar conditions Turbulence or cavitation as indicated by noise was the apparent cause For more flexibility in (Renting condishytions the bypass-loop variable-flow restrictor was inshystalled Loop parameters were then recorded at many
cwmmo
Flaquoj 21 GB4VMWM Facaw
16
17
n$ J J csrf w raquoNVJgt
coaibinaiiotts of lalt-pump speed and settings of the mam loop and hypass4oop variable-flow lestriciorv
Lug-log plots were nude of pressure drops across various sections of the loop as functions of the flow rates through the segments Ssnce the head loss for a fixed resistance is proportional to a fixed power of the fluid velocity the cams should be straight lines unless the character of the resistance changes due to cavitashytion The pSots indicated that cavitation was occurring in the main loo between the inlet to the nauvloop variable-flow restricior f FE-l02A)and the throat oi the bubble generator at flow rates above 320 gpm (1200 liters mm I with the variable-flow resiriclor set at I in (25 mm I above 470 gpm with the variable-flow reslric-tor at 2 in (100 litersmin at 51 mml above 600 gpm with the variable-flow restricior at 3 in (2300 btersmin at 76 mml and above 630 gpm with the variable-flow resthctor at 4 in (2400 litersmin at 102 mml The data were not sufficiently precise to determine whether cavishytation was also occurring in the bypass loop however noise indicated thai it was
Since the loop turbulence andor cavitation as indishycated by noise and the salt-pump shaft escalations were unacceptable at conditions required by the bubble separator design changes were made in the main-loop and bypass-loop flow restrictions By replacing each vamMe-flow restrictor with two or more orifices in series the loop noise level was decreased but there was
little or no decrease in the aaphtwdr- of the a f t oscd-btions
The amptitaae of the shaft ascafetsoas was plotted as a wactiua of salt pump speed at various operating a laquo -dMMis (Fuj 23| At salt-pump speeds less than about 1600 rpm the oscantioas were reasonably smaM and ai any given speed appeared to be unaffected by (11 flow rates between 450 aad 1 0 ) gpmlt 1700 to 4000 liters n a n M 2 ) salt-pump overpre wares between 5 and iSpsig ( I J X 10 to 2D X 10 Pal ( 3 | type of restneuon (variaafc flow restnetors orifices or a coiahmaiion ot these I or 14) flow roate (through the main loop bypass loop or both) At higher speeds the osdaatioa ampit-twe mcreased rapidly with mcieasts in speed and there was mote scatter in the data making it difficult to evalshyuate improvement in cavitation and effects of other variables However at any given speed above about 1700 rpm mcreasmg the flow rate (between 450 and 1050gpm)caused larger oscanuoas
One puaablf explanation for the increased amplitude of the osculations at higher speeds b thai the shaft is approaching its critical vibration frequency and is theiraquo-fore more sensitive to disturbances such as loop turbushylence or carnation The critical speed of this impeller assembly is 220 rpm in an which would indicate a maximum normal operating speed of 1710 rpru using bullhe normal industrial practice ot operating pumps at less than 75^ of critical speed
If the pump shaft osculations were in fact a conshysequence of operation near the critical speed ot the rotating assembly two obvious alternatives were availshyable to reduce the amplitude of the oscuHaiions
1 further reduction of the loop disturbances to minishymize the driving forces that cause oscillation
2 operation at lower speeds to reduce the osolatorv response to disturbances
The first alternative was rejected because it would have required extensive modification of the loop and it was difficult to guarantee that all sources of such disturbshyances could be reduced to satisfactory levels Design cakidaiiofls showed that the desired flow and head (3800 litersmin at 3 0 3 m or 1000 gpm at 100 f u could be obtained by replacing the present 11 Virt-diam (2ftgtnun) impeter with a l3-tn-dam (330-mail unit and operating it at 1500 rpm A larger impeller is being machined from an available HastcHoy N rough casting Since the larger impeller will be somewhat heavier than the original one it win cause a reduction in the critical speed of the rotating assembly The estimated critical speed with the new impeller is 2000 rpm which makes the operating speed 757 of the critical speed
18
n-va
I
bull
bull 4SO-C4V laquo bull TOTM run
bull bull80-KM9 laquo bull TOTH FLOW bull t
bull bull
bull
bull bull bull bull bull bull
bull bull bull bull m bull m bull
r- i bull gt
bull bull bull bull - bull jr bullbull r laquo bull 1
bull laquooo ooo rsoo i4oo CMO
SALT n w SPCEO t fraquo) lt7oo laquoaoo
Flaquo2J GSTFpanpAtfia
At a few off-design conditions during some of the bter runs the pump shaft deflection records showed random spikes in one direction superimposed on the relatively uniform oscillations described earlier These occurred with higher than normal flow rates in the main loop or at reduced system overpressure Since eidter increasing the overpressure or injecting gas at the bubble generator reduced or eliminated these random oscillashytions it was concluded that they were a consequence of cavitation at the bubble generator Such cavitation and the attendant oscillations are not expected to occur at normal operating conditions
212 Sak-Twnw f i i f i inmdash u DMa and CaKbration of the Variable-Flow Ratricton
The original design of the CSTF provided for varying the salt-pump speed andor changing the variable-flow restrict or settings to obtain different flow rates or presshy
sures needed for future experiments However instrushymentation will not be provided for measuring the bypass-loop flow rate during salt operation and only urn salt pressure measuring devices will be installed I at the salt-pump discharge and at the bubble-separator disshycharge) Also since the salt pump was modified and has a mismatched impeller-volute combination no perforshymance data were available Therefore extra pressure indicators were installed for the water tests and loop pressure profiles were obtained at various pump speeds flow rales and variable-flow restricior settings to evalushyate the pump peiformance
The calibration of the main-loop variaMe-flow restric-tor and of the salt pump at low flow rales was straightshyforward since with the bypass loop blanked off the total pump flow was measured directly by the main-loop vert tun However once the bypass-loop variable-flow restrictor was installed the calibration of it and
19
the pump was complicated Hie main-loop variable-flow restriciof was closed and the bypass-loop variable-flow rest net or was calibrated at low flow laies using the pump calibration curves established before it was inshystalled The mam-loop variable-flow restrictor was then opened to various settings and the pump calibration curves were extended by adding the measured flow through the mam loop to the flow through the bypass loop taken from the bypass-loop variable-flow reslnctor calibration curves Then using these extended head-capaciiy curves for the pump it was possible to extend the calibration curves to higher flows
The pump calibration curves (Fig 241 indicate that at 1770 rpm the pump flow rate wiB be 970 gpm 13700 litersmm) at 100 ft 1305 ml of head The ongnul design called for 500 gpm (1900 litersmmgt through each loop however the bypass flow rate can be reduced to 470 gpm (1800 liters mm) without compromtsng any of the objectives
To determine the main-loop variable-flow restrictor selling for normal operation with a flow rale of 500 gpm in the mam loop plots were made of the pump head vs flow for several settings of the flew restrict or From these a curve was made of pump head at 500 gpm (1900 litersmm) vs settings (Fig 25) A 185-m (47-mm) setting wril give the desired head of 100 ft (305 m) at 500 gpm
m - K B i
lt M M laquolaquo IFC-I02M SCTTWG FOraquo 300 laquo bull Zr-MSS laquo bull C-laquo4AJ
SpoundTTlaquoVS FOM0laquoB ^ Str-MSS vlaquoMFt-laquoolaquoi
si TlaquoK ran 47olaquopraquo
1 2 3 4 VMIASLC FLOS EST^CTO SCTTI
s
FraquoZ5
bull40 bull n-vw
C O shy
CO
l
CO bull
40 1
20 f
o 200 400 M O n o ltooo woo FUMIlaquoOTI
Fit- bullbull Hcai capacity curves for oV GSTF y mdash gt bull
The bypass variable-flow reslnctor settings were detershymined similarly 7 -I found to be 1-85 in (47 mm) at 500 gpm (lltHXgt liters mm) or 170 in (43 mm) at 470 gpm (IK00 liter v mm)
21 J Satt-Pmnp Fountain Flow
The GSTF salt pump is a centrifugal sump pump having an impeller which rotates in a volute section which in turn is located in a pump bowl The clearance between the impeller and the volute assembly at the pump inlet allows leakage from the discharge directly (o the pump suction (see Fig 22) A second bypass flow called the fountain flow escapes through the clearances between the impeller shaft and the volute assembly This bypass stream flows into the pump bowl circulates downward and reenters the main stream at the pump suction Due to the large liquid holdup and large surface area in the pump bowl significant gas-liquid mass transshyfer can occur in the fountain flow stream and herefore its flow rale is important in analyzing mas transfer processes in the loop Since the fountain Pow is not measured directly a method using mass balances on
20
measured gas flows was developed to determute thn flow rale
A lump J-parameter mcjel of the GSTF was used to develop equations Iron which an express lor ike rounfam flow was dented The system model contain two major regions the pump bowl and the primary loop Imnn and bypass segmental cutmstmg ai a fas seciion and a liquid section tach section was assumed to be perfectly mued The three enteral time-dependent equations lor a specific p s m i gas mixture are given m Tabic 21 representing gas mas balances for the pumrbowi gas section the pump-bowl tinwd section and the primary-loop f seciwn Icuculating oidsraquo
These were simplified by applying the folowmg
1 There is no gas carry-under in the pump bowl which implies that Ugt the efficiency for separation of bobshybles from the fountain flow Ut a unity and Ft -Ffi bull | + Afs-gthe bwbWe surface area m the pump howl M I the void fraction in the pump bowl frgtngt and the concentration of gas m the pump bowl (Clt I are nonappbcable or zero
2 Mass transfer equtJibnurn nasts in the primary loop which implies that the mass transfer term - j(C 4 -KRTCi )a zero
3 Steady-stale conditions exist making all time derivashytives zero
4 Ff = 0 since there was no gas purge flow during the experiments
Therefore Eq (3) Table 21 reduces to
FB FfL ltlaquo = 0 Ml Solving f o r +
By adding Eqs (1) and (2) Table 21 and simplifying
FjyenLCgtFfi +1C+FBSCX
FC Ff( rtC1FBSCJ=0 16)
By substituting Eq (5) into Eq (6) Ff may be exshypressed in terms of a quadratic equation
ltC C 2 I F bull KQi Fbdquo FBSKCt C 2 )
FgCt FCtFf
QttlF8SltC C raquo F C | 0 (7gt
Equation (7) is a general solution for the fountain flow which depends upon the gas concentrations in
each ol the three sections of the model It it is assumed that man transfer equAbmm exists at the galaquoltiugtd interlace in the pump jowl the gas conceniciuon in the pump bowl liquid | ( I is relaied to the correspondmg concentration m the pump bowl gas section tCt I raquoy Henrys law If only one gas rs involved (eg heliumK C toNows directly from the pump buwl overpressure Further since mass transfer equuawium was assumed for the primary loop ihe gas ctmcentralion m the kiop liquid (for a smgk gas) ioifews from the loop average pressure and Henry s law Thus the foil am ikm magt be evahsalaquoed from fcq |7raquo using orker known liquid flow rates and measurable gas flow rales into and owl ol the system If no mass transfer is assumed to occm~ at the gas liquid mterface m the pump bowl thr gas conshycentration m the hqmd leaving the pump bowl is the same as thai in the cmtiiug liquid lue O = C I and Eq(7i reduces to
^=IFgCyFCi I ^
Since the rate oi mass transfer m the pump bond is neither minute nor zero Eq I 7 I ni l give a low indftca-tion and Eq (X| laquo i give a high indication of the founshytain flow rate The deviation from the actual fountain flow rate win depend on how much mass transfer actushyally occurs m any experimeni If the loop void fraction is increased (by increasing the gas input rate I the conshytribution of mass transfer across the gas-liquid interface to ihe flow rate of gas laquo-ji of the pump bowl wif be reduced relative to the bubble contribution Therefore a pkn of the calculated iountam flow vs Ihe reciprocal of the gas input rate at several different conditions should give the actual fountain flow rale when extrashypolated to zero (infinite gas flow rate) usmg either Eq (7raquoor(8gt
The preceding equations and approach were used to calculate the fountain How for the GSTF pump Results from ihe plot indicated thai the curves generated were not defined wen enough to provide accurately the reshyquired extrapolations The range of fountain flows at the highest gas input rate at which data were obtained was 100 to 200 gpm (30 to 760 litersmmraquo
Even the lower estimated value for the fountain flow may excessively complicate future mass transfer experishyments so efforts will be made to reduce this flow Since ihe labyrinth clearances cannot be reduced without incurring meial-io-metal contact between the pump shaft and the volute hack vanes will be installed on the lop of ihe impeller lo minimize the differential pressure which drives the fountain flow
Iihfc 21 (iiimiuhaUmimpjallnntfitf timtpulalfcinmiMHof (iVI
KllO til illlll|tkltil |tl pill|K lllllilllis scpHlUil IMIlaquo IfMIKU nl t in nl oil Kii iiivkiilnl ill llnw ill bull limn liiiiiilini bull iliraquoraquonluil |Mgt lt mw ^JVIIHIII pinup linlaquol III yis gt|iui Him lH|iil(lniv inliHir pump Imwl
lltpi l n I lt f lt bull bull bull laquo lt laquo laquo laquo raquo laquo iff
Kllgt ill tlltllllr lllgtMi|vraquoll bullMl itlsMllVCll IV 11111 lllllslll 111111 ILIIKUM lllraquoraquolaquogtlVlaquol |l ni ittN iimMim |HiMiii in pii-witi m ni ltlin|tiil ut ilimlraquoilaquol pivwiii in iligtlaquo ilhvilvcilin liKnimiiK liuinlim llutt limn IMlaquo A I raquo laquo IM in Iniltlil trnm pump innn| Iiwl ln|iml illaquo lnihlltKIIIIIII hi|iiiil initligt in |iiini|lt linul biwl in lu|i
IH (11 Imlt vill
laquoltplllln| Kpiitiui I bull(raquo bull raquo I US gt laquo A K U i IHIl gt raquobull raquol IyjM
raquo i
KiMniil ihmvn iluw nl ilntt nl hiililiUv n u n luinl t i IIIIIIIIIOMII iliMmUinl raquoM ImhNiivinuwit bull I Civ linnillnH igtilaquo in Itmi pump Imwl I IIISSIIMII IIUIIIIIH ill lninliin In IMIMIII
III limp mill IHIIIIIU bull Inlnnp bull (ligt bull IliMJo llim llnlaquo w p j u l m llflltLllnl l l l l n i i | i
l i p u i m i I bulllaquo bull gt laquo l laquo IKH gtill M raquo O 1 raquo
22
214 The void fraction of the liquid after it leaves the I
Me separator n u n be known in ordrr to evaluate the bubble separator efficiency Densitometer mstrumenta-IWB (unwf a digital voltmeter for readout was mrtalrd at the loop and tesu were uumr using 0 3 0 0 ( 1 1 X 0 z dnsecl i raquo T a ece The effccu of void fraction were shambled by inserting pontic sheets 3 and 6 nms |0J07copy and 0152 mmi thick between the
detector and by using the mrtamc shim side m m k n steel cahVratioa plates 10 to 250
mis (0254 to 6 J 5 mm) thick which were designed for rhraquo purpose
The nail cncounteied dming dealupmtnt testing uras stal peestnt The hourly drift would be equivalent to a
efficiency of shorn 10 a h operation (assuming a void fraction of 0J
at the - c ^^hMe separator) Thus short-term tesraquoi wnl be required to ntmnunt the bdbbk jcparaior efficiencies
bullused on densitometer readings the bubble-separator efficiency was greater than 98 at various operating conauuons with water whkh it shghtty predtcted
Ft Ft
Fraquos
Ft
A -
of liquid gar interface m pump bowl bubble surface area in puop bowl bubble surface area in loop gas concentration in pump bowl gas space gas concentration sn pumn bowl hauid gas concentration in the loop bubbles gas concentration in loop liquid gts concentration m pump bowl bubbles gas concentration in gas purge entering the pump bowl gas space flow of total off-fas from pump bowl gas fltow rate to bubble generator nqiad flow from bubble separator via the bum salt separator to the pump bowl (assume no bubshybles) fountain flow (liquid and buboto) flow of gas purge into pump bowl gas space flow of liquid and bubbles from pwnp bowl to loop mass transfer coefficient for gas dissolved in pump bowl liquid to gas space in pump bowl mass transfer coefficient for gas dissolved u pump bowl liquid to bubbles in pump bowl mass transfer coefficient for dissolved gas in loop liquid lo bubbles in loop liquid
K Henrys lr~ (solubility) coefficient Q flow of bruid and buttles to bubble separator A universal gas constant r temperature
V laquo total gas volume in pump bowl V2 mlumt of wquuland bubbles m pump bowl VL = volume of drcubnutt liquid and bubbles i
loop c ( bubble separator efficiency tf efficiency for separation of bubbles from founshy
tain Aow bull t z void fraction in loop fluid
ltbullgt void fraction m pump bowl flutd
2-2 COOLAKt-SALTnamOUXX FACaUTYKSfF)
A N Sunt
Modifications to the sak coM trap (SCT) were com 1 and the loop was started up on March 14 and operated for 1279 hr to check the effcetrve-|975
of the sail titer to obtain data on salt different operating condrtmws
off-gas sample dau m preparation Work was completed on design
and checkout of the trita the tritium test
generation rates and to obtain salt and for the tritium tests fabrication addition system started At the end of the report period two tritium additions had been completed aad plans were being made for additional tririum addition tests as well as tests designed to examine how the tritium behavior is affected by the infection of steam into the sail
221 Laap Opossum
The SCT flow tnes were disconnected from the sysshytem and the loop was started up on March I 1975 The loop operated continuously until May 6 1975 when it was shut down to permit insinuation of otnp-ment in the containment enclosure for the tritium tests The loop was started again on June 271975 and it was saB in operation at the end of the report period when more than 2500 hr of operating tune had been togged without pHajgmg in the off-gas tine This is convincing evidence that the salt nust filter has been effective since the off-gas Ime had piuggct after only 240 hr of operashytion before the nasi fdier was instated
The loop is operating at a pump speed of 1790 rpm (estimated salt flow rate 54 literssec) and a pump bowl
2 A N San MS 2$ 1975 OKNL-50t7t 25
J IMttI
Avar Rrp Frb
23
praquo overpressure ol 2hi X IU5 Pa (20G0 mm 1 absi The pump bowl oit-^u flow which consuls ui helium coniammg a tew percent of BF prm trace quantities ol condenuMe material is about 2 litervmm iSTPl- The BF i concentration ltraquoi the oil-gas rraquo a tuncnon ol the bull1-1 partial pressure in the tail which in lurn raquo a strong unction in the tail lemprfaiuie txcept Im short period raquoi lime when special tests required a different retime the valt circulating tempetature haraquo beet mauv lamcd ai 535 lo 540 ( at which pomt the BF concenshytration in she oli-ga dream is about 25r by volume The loop otf-garaquo stream emepf tor a 100-cm1 turn wmpk gti ream iv paued through a 72(cuht iraptdry ice alcohol bath | Material which is a dtn while toiid ai itap temperature and a dirty brawn ilmd upon warmshying to room temperaiuie and which is rich m tnimm (about 1(1 nO el continue ilaquogt collect m the cold trap at a rale laquogtt I igt lOngcm (STPlotKff-ga Thnmaie-iial rraquo believed lo be a variable mixture who- compos-lion depends on the relative partial pressures ol BF HFand H Ooser the salt (see Sect 41i
A ol 000 on Auguvt 31 Ilaquo75 the bullop had accushymulated 3073 hr ol sail circulating tune smce being reactivated in Decembei |raquo74
222 Salt Mat Test
Bemeen March 25 Ilaquoraquo75and April 24 Iraquo75 a series ot icsigt wj run lo determine ihe concent ration ot wit
t m the off-fas stream as a runctwu ot a l t tempera-lure aad BF flow for each lest the loop operating coadaioas were set at the desired values ami the off-fas stream was shunted through a metamc 5- to deg-m (iter whKh was inserted mto the ait-sample access nozzle on the pump howl The sal mat concentration was calcushylated usmg the fan m weight of the filler aad the total flow sf fas A total of tea teas were earned out The test tune was nnrmatty about 12 to 15 hi but in two cases it was shortened tc about 3 hr because at the buildup ot a high-preawiie drop acroa the fdter Pump bowl pressure was 2Jb7 X 10 Pa and total off-gas flow was 1 litervmm (STP| When BF was added to the helium entering the pump bowl the BF flow was ad-msted raquo (bat the BF partial pressure m the mcomuig gas was the same as tFe calculated psttial pressure of the BF over the salt asswmng the eutectic mixture ot NaBFlaquo acd aF The salt drcutatiag temperature was controlled at either 535 or 620degC The observed conshycern rations ol mtst m the off-gas (Table 22) ranged Irom MOO ng on ai the loner temperature ibdquo as mgh agt 500 ng cm 1 al the higher temperature At the lower temperature where the expected partial pressure of BF in the sail raquoalaquo low the addition of BF with the cover gas was ineffective m reducing the amount ot ~ist in the off-gas At the hajtter temperature Hugher BF
P 27
23 CSTTi 175
VJ St Bt rcmrvrjrurr ijpampr rtlaquoraquo
t gt prepare iraquom mmSTPgt bull mm tic
raquo
Sjir imit iltgtikrgturjiraquogtn IIK Jr o n laquorr if-jtni
2fraquo |ltraquoS
raquo 25laquogt
5
Ifco
Klt-tft Zgt
5 5-532
bulltnrrlaquoflr 4Vlt
H
ion
Avrufr laquoi
11 i KX
KvrisfX 15
Vtumi^r Ih niKviic bull HtipgtltJium
24
partial pressure in the salt) a significant reduction was observed in the mist concentration when i lFj was added with the cover gas However it was not reduced to as low a value as at the lower temperature These results whie not completely definitive suggest that bull F evolution from the salt may no be the only mrst-producing mechanism in the pump tank that is simple mechanical agitation of the salt in the pomp bowl may abo produce some mist In addition no data were obshytained with excess BFj concentrations m the cowr gas Since the mstaflatioR of the salt-rust iHter in the off gas line was effective in eiumnating the operational probshylems in the CSTF caused K v the mist further investigashytions of methods to lirnii or control the mist have been deferred m favor of experiments to study tritium beshyhavior in the system
The decision to use tritium rather than deuterium a a test gas4 in the CSTF necessitated additional design effort and a somewhat more elaborate test setup in order to satisfy apubcaMe radiation safety require-meats A conceptual design was prepared for he tritium addition system and a preimnnary radiation safety analysis was performed for the proposed test Engineershy
ing design procurement fabrication and msiaBauon of the tritium addition system were completed by the third week m June 1975- The addition tube and the addition procedure for tritium are essenttaly the same as those devised for the addition of deuterium The rwer tube of the addition assembly is pressurized with hydr-jgen contanung a small amount of tritium and the gas is avowed to diffuse through the Hastefloy N tube which loom the lower end of the addition tube and which is immersed in the flowing salt stream (see Fig 2oraquo The HasteSoy N lube is 120 mm long by 127 mm in OD by 106 mm m ID and provision p made to fasten metanurped specimens to the upstream faje The portion of the addition tube inunedntely adjacent to the HasteRoy N section is surrounded by an evacushyated annuius monitored to check for extraneous tritium leakage The hydrogen-tritium mixture is passed through a purifier (M-Ag tube) to remove impurities such u O Ngt and H G which might interfere with the permeation process The probe volume ~p (infecshytion tube plus adjacent tubing) and a calmrated refershyence volume are interconnected and pressurized with the H - T mixture at the start of the test The two volumes are then isolated trom each other whne the addition rs in progress At the end of the addition
-Owe 75-T2CW
TRITIUM TRANSFER CYLMOER
4 0 0 C
sect laquo r 2^
1 SAMPLE
VACUUM ltS)
ampQ- ]
HYDROGEN
VACUUM ANNULUS
INJECTION TU8E
|StT2
35-C
lOO-C
FLOW 532laquoCi
Fig 2 T w mdash aUthnm ygtw far CiSTF
25
period the difference m pressure between p and V is recorded then the two volumes are equdibrated and the final equilibrium pressure is recorded The initial and fwal pressures ir lppx and pz respectively the foul equilibrium pressure p and the known volume and temperature ot lgt are then used to calculate the amount ot fas which pernxated the addition probe according to the equation
laquogt PiPi Pi V bdquo = _ x ^ try Pzraquo PT
where n is (rK number oi moles ltgti gas transferred R is the molar gas constant Tr is the reference volume temshyperature and the other symbols are as previously deshyfined
During the addition the amount oi extraneous leakshyage i calculated from pressure rise measurements in the evacuated annulus and this quantity is subtracted trom n to obtain the net amount oi gas iransierred into ihe salt The tntium content ot the hydrogen-tritium mixshyture is determined by mass spectrometer anaksu and Ihe net amount ot added tritium is then caicuiated
Tritium land hydrogen) which enters the salt stream rs assumed either to rematR in the sail laquo iraquo leave ihe sail by one ot two paths eiiher hy permeation through the walls ltgtl ihe loop piping or by irartsler to the gas phase in ihe pump howl or in the sail monitoring vessel iSMYl and leaving the loop raquoih the oii-gas stream During and ailer ar addition the tritium conieni ot the sail is monshyitored b lakmg samples raquot salt trom ie sail pool n ihe pump bowl or in ihe SMV and ihe irmum content oi ihe oil-gas stream ts rrhMMored hv takiru sampics from he oii-gas line ai a point ahoul I m downstream bullgt ihe rramp bowl The oil-gas sample stream is pasted first through a water trap to collect chemicaiiy ^gtmh-neltl I water-slaquo M unlet tmium and then through an oxidizing atmosphere to convert eiemeniai iriiium io iniiaied water raquohkh is c-iliecled in a seciid irap The tritium conieni oi the salt samples and ltraquoi hoih ihlt oil-gas samples are determined hy a scintillation cHinimg techshynique During the iniiul tritium addition experiments no provision was made IlaquoH measuring loop wait petnva-lion so lhat ihe tritium lost hy this mechanism is assumed |o he Ihe ditferenlaquoe hefwven the arnouni of Iniiiim aided and ihe sum oi the quantities w-hich ieave in ihe oii-gas stream and which remain in the sail
firing the March 14 Igt~v | 4 y |ltrgt bdquopei almg period a number of sail and off-gas samples were taken fo obtain baseline raquoaJues |o minim concenira-lion and lo shake down and evaluate the sampling tech-ii-ities During sluiidown oi lthe CSTI- in Magt and June
Iraquo75 the intium addunn probe was msiaUed in the survediance-spei-onen access tube and the final installashytion work was done on the tnUum addition system A stainless steel valve (HV-255AI and some stainless steel tubing which were part of the original off-gas sample-line installation were removed and replaced with a Mood valve and Hastelloy N tubing because it was ieii that the Monti and HasteUoy N would be less likely to react with the off-gas sample stream Two 2-5-cm-diam X 45-cm-long KastelkA N lubes were filled with sail from the dram tank and set aside as representative samples oi the salt as it existed prior to the start oi the tntium tesis-
On June Z~ I~5 the mop was filled and salt cirvuia-tion was resumed Several additions o i hydrogen raquoere made to check out the operation of the addition system aid to obtan data on permtaiior rates A loul or bull J cm M f l oi hydrogen was added in ihese rest and the last addition lt raquol an STPraquo was made -gtn July Jfs Ilaquoraquo~5 with ihe addition tube pressuried to I_gt~ X It) Pa the measured permeation rale was about laquo cm hi ipared with a predicted value i raquo era hr The Iirsl addition o iriiium was made on July l~ i _ 5 and a second addition with CiHlditmns essenziaili he same as iraquor the fust additnm was made August 5 1 _ 5 In each case sail and oii-gas samples were taken during ihe tritium ad Inigtft lahoui 10 hri and or atgtraquou 2 weeks afterward until sample resuiis indicated Tf at the intium levels had returned io iheu pretest values or had Mahihed Oaia lot calculatufi o ch-e amount o addej ps are sin win in Tabic _ A maihemaiica analysis and discuss of ihe tampie results are presented in Se^ i i
TaMr 2J Jtwtmm JMIIPO 4U far CSTI rnf
f rr runilv-r 1 i lraquojrc ~ ~y s r
ti4iilaquon vijrTrJ i raquo bullxt ltMiri-n erxteJ - gt lt o -gti VMiTfcltn -aw bullgt t N bull Im-ijS p-i-uir^ TjiTa i s j r bull bull bull 1 raquoUl prcraquoMraquorf p~ ltti bullraquo laquo bull r - t |utftt -nm p-riu-r r f^i a bull laquobull 1 bull 1 r v-jirrlt- m i i gt i i
fr Tcmr^r 4u-r k bull laquo lt l l bullbull ltrr gt rv-Tltjriraquor - r m -raquo raquo i 1 bull bull raquolt--laquo-f i e j l -j -lt- rn bullbulllt raquo raquo 14
i--tTWjTl-raquon - J 7T1 bull - raquo bull bull gt |TTti-n -raquonltf n TilaquoT in nisfi ii bull bull bull
ra^ pr^i l--l i m u M e i laquo m i it it X bull bull
1 bullbull J irmm j dea bull ml 11 raquolt bull
26
2 J FORCEftCONVECTlON LOOPS
W R Huntley M D Silverman H fc Robertson
The Forced-Convection Corrosion Loop Program is part of the effort to develop a satisfactory structural alloy for molten-salt reactors Corrosion loop MSR-FCL-2b is operating with reference fuel salt at typical MSBR velocities and temperature gradients to evaluate the corrosion and mass transfer o( standard Kistelloy N Addition of tellurium to the salt in MSR-FCL-2b i olanned after baseline corrosion data ire obtained in me absence of tellurium At this time the loop has operated approximately 3000 hr at design ST conditions with the expected low corrosion rates
Two additional corrosion loop facilities designated -ISR-FCL 3 and MSR-FCL4 are being constructed They arc being fabricated of 2T titanium-modified Hastelloy N alloy which is expected to be more represhysentative of the final material of construction for an MSBR than standard Hastelloy N
2 JI Operation of MSR-FCL-2b
Loop FCL-2b was operated continuously for about 3000 hr from February to June lraquo75 unuer design ST (565degC minimum 70SdegC maximum)conditions During this period standard Hastelloy N corrosion specimens installed in the loop in January 1975 were exposed to circulating fuel salt at three different temperatures (565 635 and 705degC) As expected corrosion rates were low the highest value was 01 mil year Ojimyear) at the highest temperature station
Salt samples taken at intervals have been analyzed for major constituents metallic impurities and oxygen (Table 24) Except for an occasional high value for oxygen or iron the analyses are relatively consistent and indicate that the observed corrosion processes have had very little effect on the concentrations of the various species present in the fuel salt Analytical probe readings for the VIU ratio indicative of the redox condition of the salt have been taken on a weekly basis This ratio which wraquo about 7 X I0 3 at the beginning of the corrosion run rapidly dropped to about I X | 0 3
after the first 24 hr of operation The ratio then gradushyally fell to A I X I0 1 by the end of March CVI500 hr elapsed time) and it has remained at that level during the latter part of the operation
After the corrosion specimens were removed for the 3000-hr weight-change measurements preparations wei nude for obtaining htat transfer data on the Li-Be-Th-U fuel salt (717-16-12-93 mole ) At this
time a Calrod electric tubular heater failure was disshycovered on the pipe line (i 27-mm-OD X 11-aim-wall) which runs from metallurgical station No 3 to the inlet of cooler No I After removing the thermal insulation about 10 to 20 cm 3 of salt was found on the loop piping and the bumed-out heater Grainy material was present on the heater sheath at three locations directly opposite peeled-off sections of oxide layer on the Hastelloy N piping A small crack (A 5 mm long) was found on a tubing bend directly under the failed heater Whether the heater arced causing the piping to fail or whether the salt leak from the loop caused the healer burnout is uncertain at this time Examination of specishymens from these regions is continuing
The fuel salt was drained from the loop into the fill-and-drain tank after the leak was discovered Analytical results on a sample taken from the tank indicated that no obvious contamination of the fuel salt had occurred A new section oi tradeping was installed (approximately 24 m from metallurgical station No 3 to the inlet to cooler No I) During the shutdown several defective thermocouples and two defective dam-shell electric heaters were replaced Ball valves were refurbished numerous small repairs were made and instruments were recalibrated After the thermal insulation had heen replaced baseline heat loss measurements were made with no salt in the loop in preparation for taking heat transfer data The loop was ready for refilling at the end of aly approximately four weeks after the salt leak was discovered After filling the loop heat transfer measurements were obtained with flowing salt The ALPHA pump speed was varied from 1000 to 4600 rpm resulting in salt flows of approximately 27 to 16 litersmin which correspond to Reynolds numbers that vary from 1600 to 14000 The lower limit for salt flow was set to prevent freezing and the upper limit was dictated by the power required foi driving the pump At the lowest flow rate unusual wall temperature profiles were noted which probably were caused by entrance conditions and transitional flow effects The heat transshyfer measurements were completed near the end of this reporting period and analysis of the data is in progress
The stringers containing the Hastelloy N corrosion specimens were reinserted in the loop and ST operashytion (S65degC minimum 705degC maximum) was resumed in order to complete the originally planned 4000-hr corshyrosion run If no unusual corrosion behavior is encounshytered in the next 1000 hr of operation nickel fluoride (NiFj) additions will be made to the loop in order to raise the oxidation potential of the salt to a level correshysponding to a U^U3 ratio of about I0 3 and a new set of corrosion specimens will be exposed
27
raw t u si tioalaquolaquofcUF-laquofF -ThF-UFlaquo
i-im
Sanpfe Mo
Date impkd (197$)
Total hoars of a i l
arcabboa bullhel saatptcd
Major coapoMMs TIJCC ameiub Notes
Sanpfe Mo
Date impkd (197$)
Total hoars of a i l
arcabboa bullhel saatptcd Li Be Tb U F Fe a f t O C S
lb 1-17 0 78 221 43-2 I I I 467 101 40 23 lt50 I I 99 Flash salt 2b 1-23 48 60 42 52 3b 128 0 799 174 430 an 463 75 70 15 125 29 4 3 New sail 4b 2-11 177 137 63 60 75 Sb 2 18 355 154 64 68 45 6b 2-24 498 98 63 28 48 7b 3-3 676 7 8 236 4 2 J 105 463 147 67 35 45 23 17 bullb 3-25 1146 7UI 255 430 104 458 256 59 57 lt2S 14 9 9b 4 16 1647 816 229 432 097 452 $ 70 30 20 78 15
10b 5-12 2197 829 264 430 103 455 62 85 30 60 l i b 6 4 238 823 225 427 100 445 30 70 25 140 12b 6-23 3173 820 208 433 104 451 35 75 25 152 13b 7-3 3177 830 218 430 10 452 70 80 40 30 FaVaaa-dran
oak Mb 8-7 3246 728 203 454) 100 450 45 85 70 58
7|7-16-i2-03 mole bull
232 Desia Mid CoastnKtkm of FCL-3 raquossrfFCL4
The design work for FCL-3 and FCL-4 was essentially completed any changes or revisions which occur during construction of FCL-3 will also be made on FCL-4
The piping support frame for FCL-3 was installed and installation of electrical equipment is proceeding- Conshyduit lines have been fin from the variable-speed motor-generator set on the ground floor up to the electrical rack installed on the experiment floor and a sizable
number of transformers starters switches etc have been installed The instrument panel cabinets have been positioned and cable trays are now being installed Fabrication of two ALPHA-pump rotary elements and two pump bowls is 90 complete A large number of completed items for both loops (eg dump tanks auxilshyiary pump tanks cooler housings blower-duct assemshyblies electric drive motors purge gas cabinets etc-) are on hand awaiting installation Fabrication of the titanium-modified IrasteHoy N tubing for the salt piping of the loop is in progress
Pan 2 Chemistry
L M Ferris
Chemical research and devdopmen rdated to the design and ultima^ operation oraquo MSBKs are itill conshycentrated on fuel- and coolant-salt chemistry and the devdopment of analytical methods tV-r use in these systems-
Studies of the chemistry of tellurium in fuel salt have continued to aid in elucidating the role of this dement in the interranular cracking of Hascdioy N and related alloys An important initial phase of this work involves ihe preparation of the pure tellurides Li Te and LiTe3
for use in solubility measurements loop experiments clectroanaiytical studies and studies of tellurium redox behavior in molten salts Technique for preparing these idlurides have been developed and experimental quanshytities have been prepared Spectroscopic studies of tdlu-rium chemisfy in m-jlten salts and of the equilibrium H(ggt + UF 4 |d) = UKj(d) + HF(ggt have also been
initiated In work using molten chloride solvents at Lust tvo light-absorbing tellurium species have beei shown in be present These species are as yet unidentishyfied but have compositions in the range Li2Te to LiTe4 Preliminary values of the quotients for the above equilibrium have been obtained using LiBeF4 as the solvent These values are in reasonable agreement with those obtained previously by other workers
A packed-bed electrode of glassy carbon spheres was constructed calibrated with Cd1 ions and used in experiments with Hi1 ions in LiCI-KCI eutectic It was concluded that this electrode was prototypic of orie (hat could be used for the electroanalysis or electrolytic removal of bismuth oxide and other species in MSBR fuel salt Preliminary experiments were also conducted lo evaluate some questions relating raquoo the mixing of fuel
and coolant salts The results suggest ihat or mixing small amounts oV coolant salt with large amounts of fuel sal the rate of evolution of BFj gas will not be intolershyably high and that somj oxide can be present in the coolant salt without effecting precipitation of L0 or ThO - Lattice enthalpies of first-row transition metal fluorider were calculated to provide a theoretical basis for evaluating thermochemical data gtr svructural-metal fluorides
Work on several aspects of coolani-sait chemistry has continued Analyses of condensates from the Coolant-Salt Technology Facility (CSTF) indicate that the vapor above (he salt is a mixture of simple gases such as BFj HF and H 0 rather than a single molecular compound Tritium concentrates in the condensates by about a factor of 10 s relative to the salt Studies of the system NaF-NaBF 4-B 0 at 400 to 600degC show that at least two oxygen-containing species aie present in typical coolant salt One species is Na B F 6 0 j while the other has not yet belaquon identified
The development of analytical methods for both fuel and coolant salt was also continued An in-line voltam-metric method was used to monitor U^U 1 ratios in two thermal-convection and one forced-circulation loops Two additions of tritium were made at the CSTF The salt in the loop did significantly retain tritium and the tritium ultimately appeared in the off-gas Work was begun on using various electrodes for determining iron in MSBR fuel salt Previous work had been conducted with solvents that did not contain thorium Preliminary voltammetric experiments were conducted to identify soluble electroactive tellurium species in MSBR fuel salt
28
3L Fuc-J-Scik Chcmism
ADKeimers
31 COMPOUNDS IN THE LITHIUM-TELLURIUM SYSTEM
D Y Va^ntine A D Keimers
It has beei k-mcns rated that tellurium vapor can induce shallow grain-boundary attack in Hasiefloy N similar to that observed on the surfaces of the fuel-salt circuit of the MSRE However the actual oxidation state or states in which teilunum is present in MSBR fuel salt an LiF-BeF-ThF4-UFlaquo mixture and the chemical reactions with the Hastelloy N surfaces remain to be determined The lithium-tellurium system is being investigated to determine which Li-Te species can be present and to synthesize samples of all possible lithium tetlurides- The solubility of these compounds in the fuel salt will then be determined In addition they will be used in spectrophotometry- and electrochemical investishygations of tellurium species in melts
During this report period sample of LijTe and LiTe
were prepared The preparations were made in an argon-atmosphere vacuum box equipped with an enshyclosed evacuated heater which held a molybdenum crucible All handling of Li-Te compounds was done in inert-atmosphere boxes sometimes the compounds were sealed under vacuum to minimize oxygen nitroshygen or H 0 contamination Lithium having an oxygen content of ltI00 ppm was supplied by the Materials Compatibility Laboratory Metals 2nd Ceramics Divishysion Tellurium metal of 99999 wt Tr purity was obtained from Alpha Ventron Products
The Li2Te was first prepared by dropping small pieces of lithium into molten ellunum contained in a molybshydenum crucible at 550degC The reaction was extremely exothermic emitting fumes and light tlashes after each lithium addition Solid formation occurred at lower lithium concentrations than expected from the reported phase diagram2 Further lithium additions continued 10 be absorbed after first melting on the surface of the solid phase An amount of lithium necessary to satisfy Ihe Li2Tc si gtichiomeiry was taken up in this manner However because of the loss of vapor and of some solid material which splashed out of the crucible during the early additions of liihium it is doubtful that the stoichi-omclry was in fact preserved
The x-ray diffraction pattern showed a single phase identified as LijTc having a face-centered cubic strucshy
ture with a lattice parameter of 65119 t OJ0O0Z A J
The oxygen contamination in the product totaled about 375 ppm- Spectrographs analysis reported 0-5 wt ~ molybdenum present Since the oxygen level and moshylybdenum impurities were fairly low a larger-scale prepshyaration wts attempted as well as a direct preparation of LiTcj by the same method In both cases rv product was contaminated unacceptabiy with molybdenum and these preparations were discarded Apparently the first preparation had affected the surface of the crucible such that the reaction with molybdenum was accelershyated in these subsequent experiments
The molybdenum crucible was used for one further preparation after cleaning and polishing the inside surshyface The Li Te was prepared from the lithium-rich side of the phase diagram by dropping tellurium info molten lithium Since molybdenum is relatively inert toward lithium4 less reaction with the crucible was expected In addition this preparation could be made at a much lower temperature The tellurium was added to the lithium in small increments with the temperature held at 250degC Each of the first additions resulted in a smooth quiet reaction with a solid phase forming on the bottom of the crucible However since completion of the reaction was not visibly apparent the temperashyture of the system was increased above the tellurium melting point to about 550degC to ensure that unreacted tellurium was not on the bottom of the crucible More additions of tellurium were then made Above 500degC a popping noise was heard after each addition of tellushyrium After about three-fourths of the tellurium had besn added the system was mostly solid As more tellushyrium was added the amount of solid in the system became so great that further additions of tellurium were
I A D Keimers and D Y Valentin MSR Program Semi atmu Profr Rep f-eh ltlt 1975 ORNL-5047p 40
3 P T Cunningham S A Johnson and F i Cairns Vlectrmhem Soc Klrcirochrm Set Tech 120328(1973)
3 X-ray lattice parameters were measured by O B Cavin of the Metals and Ceramics Division The value 65119 00002 A measured tor IiTe is in agreement with the value 6SI7 A reported by K Ziml A Harden and B Dauth Hlektrochem 40 588 11934) The value 61620 bull 00002 A measured for LiTe is in agreement with the value 6162 A reported in ref 2
4 H W leavenworlh and R F CUaryAcu Mel 9519 11961)
29
30
not covered by the liquid Subsequent additions proshyduced light flashes and poppng associated with the highly exotherrmc reaction as encountered m the preshyvious preparations oi Li Te FuuBy enough additional tellurium was added to the sgt-stem to satisfy the Li Te stoictuonietry and the system was aflowed to cool to room temperature
Upon crushing the cooled product fow differently colored substances were distinguishable gray opaque material wine-red to pink opaque material colorless translucent crystals and metafile tellurium Analyses were performer separately on each type of material
1 Gray opaque material The x-ray diffraction pattern revealed LigtTe and LiTe no other lines were present The oxygen level was about 218 pom Specshytrograph analysts indicated the presence of about 01 w t molybdenum
2 Red-hue material Only a few crystals of all-red material could be isolated The remainder of the red-hue material was ground together with some surshyrounding gray material The x-ray diffraction pattern corresponded mainly to Li2Te A small amount of LiTe was also preset The oxygen content was reported to be about 275 ppm Spectrograph analysis reported lt00I wt 9 molybdenum
3 Colorless translucent nd isolated red crystals Both these products gave an -ay diffraction pattern corresponding to pure Lij Te with no indication of a second phase
To ensure a uniform product all the various colored materials were recombined and thoroughly mixed The LijTe mixture was then placed in a 2-in-diam tungsten boat which had previously been enclosed in a quartz bottle The quartz bottle was then evacuated sealed and heated to 550degC for about 16 hr The product obtained after cooling was almost completely cream-white However when the bottle was broken open the product began to turn beige upon exposure to the envishyronment of the inert-atmosphere box The product was then crushed roughly and placed in sample bottles On standing in the bottles the product gradually reverted to the red-gray color it had been before the heat treatshyment with the exception that the product in one bottle remained beige The reason for the lack of uniform behavior is as yet unknown Some of the darkened product was returned to the tungsten boat in another quartz bottle and (he heat treatment repealed it again turned the cream-white color The products both the light beige and the red-gray color forms gave x-ray difshyfraction patterns for a single phase LijTe Analysis of this LijTe is given in Table 31
T l r 3 J ABMywafU-TcaaJliTc
UU t i l r
l l lVI 1 laquo 5 - MI 1 - bullbull It IWI ~ raquo raquo - bullbull 5 Sraquo 4 r II 5
Li TV IMgt4T I mj r i LiTe bullbulln4r ~ bull 14- 05 XI lt - 5 raquo Innh4r ~ l ITI - 1511
-fjgt diftraciMi SMctcpfc SWfJr rhue 0ypm ipeani 740lltr l 275tMrri
MatyMtmdash i w i 005 ltlaquoraquo0I
T w p m iwt i lt00l lt 0 laquo l
Red-gray Li2Te was mixed with the amount o( tellushyrium required to satisfy the LiTe stoiduometry The mixture was then sealed in a qurtz bottle under vacuum and heated to 550degC for 2 hr The not liquid was dark metallic gray On cooling the solid appeared bright silver-gray The x-ray diffraction pattern conshyfirmed the presence of a single phase LiTe having a near body-centered cubic structure with a pscdo-ell lattice parameter of 61620 plusmn 0D002 A J The well-exposed Debye-Scherrer diffraction patterns suggest that the structure of this compound is more complex than previously reported2 Work will continue in an effort to describe this structure The oxygen content was reported to be 275 ppm Spectrographs analysis reported no molybdenum or tungsten contamination Analysis of this LiTe3 is also given in Table 31
3 2 SPECTROSCOPY OF TELLURIUM SPECIES IN MOLTEN SALTS
B F Hitch L M Toth
A spectroscopic investigation of tellurium behavior in molten salts has been initiated to identify the species present in solution and to obtain thermodynamic data which will permit the determination of the species redox behavior in MSBR fuel salt A previous investigashytion 1 had indicated that Te~ is present in LiF-BeFj (66-34 mole ) on the basis of an absorption band occurring at 478 nm when LiTe was the -Jded solute however the work wai terminated before these observashytions had been fully substantiated The current work is an extension of those earlier measurements which
5 C K Bamberger i P Young and R G ROM Inorg Suel Chtm 36115raquo U974)
31
should lead ultimately to a measurement ol redox equishylibria such as
LiTe bull H bull 5LJF = 3Li2Te bull 5HF II)
^Te bull LiF + ^ H = LiTe + HF 1
These data should then permit the prediction of teilu-num redox chemistry as a function oi LF gt l T F 4 ratio
During the past several months most ot the effort was devoted to assembly oi the apparatus necessary for the fluoride measurements Ths involved fabrication and assembly- ot the following furnace for the fluoride studies diamond-windov ed specirophotometrk cells a vacuum and inert gas system and a KHF saturator through which H is passed to generate HF-H mixtures of known proportions
Also during the period of preparation some attention was given to a supporting study in chloride melts The advantages of working in chlorides are
i previous ground-work investigations have already been reported7
2 chlorides are easier to hold in silica cells without container corrosion
3 the greater solubility oi the tellundes in chlorides may reveal greater detail because oi more intense spectra
Atsorption spectra have been measured for LiTo LiTej and tellurium solutes as well as during titrations of LijTe with Tej in the LiCTKCl eutectic 31 450 to 700degC These data indicate that at least two light-absorbing species are present in molten chlorides conshytaining lithium tellurides with compositions in the range LiTe to LiTe4 Furthermore an examination of Te 2 in the LCl-KCI eutectic has indicated thai there is a second species present besides Te which is formed at high temperatures andor high halide ion activity More detailed experiments are anticipated using purer lithium lelluride solutes in the diamond-windowed cell to demonstrate (hat (he additional species are not related to impurities from the reagent or silica corrosion
6 This work has done in cooperation with J Bryncsfad of I he Metals and Ceramics Division
7 I) M Cruen R I McBclh M S I osier and ( Y (roulhiimcl Phys Otcm 70i2t472 (l6gt
3 J URANIUM TOTRAFLUOftDE-HYMOGEN EQUIUHUUM IN MOLTEN FLUORIDE SOLUTIONS
L O Gilpatnck L M Toth
The equilibrium
LF 4ldraquo4H2lg) = UF J ldraquoHF|g) HI
is under investigation using improved methods of analyshyses and control The effects of temperature and solvent composition changes on the equilibrium quotient
Q = rraquo
are the immediate objectives of this work and are sought to resolve previous discrepancies noted in fuel-sal redox behavior
The procedure involves sparging a small (approxishymately 1 gl sample of salt solution (UF 4 concentration of 0038 to 013 mole liter or 0065 to 022 mole rgt) with H gas at 5S0 to 850degC until partial reduction of UF 4 to UF 3 is observed HF is added to oxidize the desired amount of LF j back to UF 4 When an equilibshyrium between the HF H gas mixture and the UF 3 -UF 4
in solution is reached a spectrophotometric determinashytion of the UFj and UF 4 concentrations is made These data are combined with the analytically determined HF(H2) ratio to obtain the equilibrium quotient at a given set of conditions
The assembly of the system for this experiment has been completed and measurements of equilibrium quotients using LiK-BeF (66-34 mole ^) as the solshyvent have been initiated Some delay has occurred because of trace water in the HFHj sparge gas which was responsible for the hydrolysis of uranium tetra-fluoride and the subsequent precipitation of 1 0 The problem has been partially alleviated by treatment of the KHF saturator gas supply lines and spectrophotoshymetry furnace with fluorine at room temperature Howshyever back diffusion of water vapor into the furnace from the exit gas line has also caused substantial solute losses and has been reduced by using higher HF-H2 flow
This research in support of the MSBR Program was funded by the KRDA Division of Physical Research
H I O Gilpaimk and L M Toth The Uranium Tetrafluoridc Hydrogen Fquilihnum in Mollcn Fluoride Solushytions MSR Pnygram Srmunnu Progr Rep Feh u 7 s ORNI-5rt47p43
32
rates Together these modifications have reduced the totute Kisses to an acceptable level (2^ per day i
Equilibrium has been achieved at 650X lor measured I F VFj ratios of approximately 02 X IG to X 10- Although the I F VF 4 values are reproducible a fixed KHF saturator temperatures the aaalyiicaily detennined HF values are not as yet Consequently the standard error (approximately 50lt) in the equilibrium quotients is soil rather high So tar a value ofQplusmn 10 has been determined at 650degC which compares favorshyably with the previous value of 116 X I 0 T Most of the immediate effort is being Jevoted to improving the precision of the HF determination
Tritium control in an MSBR would be favored by higher equilibrium quotients In an MSBR the I F UF 4 ratio will probably be fixed by equilibria involving the structural metals The tritium inventory will be established by the tritium production rate and the various tritium removal processes UQ is larger than previously anticipated the partial pressure of HF would be higher and the partial pressure of H would be lower than previously estimated Thus TH would be available at a lower concentration for permeation through the heal exchanger to contaminate the coolant loop (and ultimately the steam system) and a larger proportion of the tritium would be present as TF which would be removed in the helium gas stream
34 POROUS ELECTRODE STUDIES IN MOLTEN SALTS
H R Bronstein F A Posey
Work continued on development of porous and packed-bed electrode systems as continuous on-line monitors of the concentrations of electroactive subshystances especially dissolved bismuth in MSBR fuel salt In previous w o r k 1 0 a prototype parked-bed elecshytrode of glassy carbon spheres (MOO microns in dishyameter) was tested in the LiCI-lCCI eutectic system Linear-sweep voltammetric measurements carried out in the presence of small amounts of iron and cadmium salts showed that the cell instrumentation and auxilshyiary systems functioned successfully and demonstrated
9 G Long and F F Blankenship The Ftahiliiy of Uranium Triflimhde ORNL-TM-2065 Part II (November 1969) p 16 Kq 6 with xjyt - 0002
H H R Bronstein and F A Posey MSR Program Semi-anmi Progr fP raquolaquo Jl 1974 ORNL-5011 pp 49 51
II H R Bronsleir and F A Posey HSR Pro-am Semi-anmi Progr Rep reh 2H IV7S ORNL-5047 p 44
the sensitivity of this method of analysts However these measurements showed the need tot redesign oi the experimental assembly to permit removal and replaceshyment of the cell and addition of substances to the melt
During this report period the redesigned packed-bed electrode of glassy carbon spheres was tested again in LiCI-KCI (5SJMIJ mote ) eutectic since the beshyhavior of a number of electroactive substances has alshyready been established in this medium The packed bed of glassy carbon spheres was supported on a porous quartz frit and contained in a quartz sheath Another porous quartz frit pressed on the bed from above A glassy carbon rod penetrated the upper quartz frit to provide compaction cf the bed ana electrical contact with a long standee steel rod which was insulated from the surrounding tantalum support tube The oiectrode assembly was dipped into the melt so that the molten salt flowed up through the interior oi the bed and out an overflow dot By this means il was possible to obtain a reproducible volume of melt inside the packed-bed electrode
Voitairmetric and coUometric scans of the pure melt at 3raquo5degC showed that the background current was small A typical set of current-potential and charge-pountiai background curves is shown in Fig 31 - A 2-V
1 1 I flmdashImdashTmdashImdashraquomdashbull 1mdash T I mdash T 1 1 T mdashi 1 I I bull 1 l - laquo 0 0
to 0 5 0 0 -OS 10 IS ELECTKOOC P0TpoundlraquoTiraquoi ( n bull laquolaquoamp) (raquobull$)
Ffc 31 Linear-sweep voUMimetry and coalonef ry of cadshymium in LCI-KCI (588-412 mole gt eutcctic with a packed-bed electrode of glassy caboa spheres Curve A current backshyground (sweep rate = 10 mVsec) curve B current with Cd present (sweep rate = 5 mVsec) curve C background charging curve (sweep rale - if) mVsec) curve D charging curve with (d present (sweep rate = 5 mVsec)
33
range ot electrode potential could be swept without evidence of significant amounts ot ouduable or reducshyible impurities in the meli For calibration purposes a known quantity ot -radmium ions lCdgt was added to the melt lraquoy anodiation ol molten cadmium metal conshytained in a specially designed graphite cup which could he lowered into the melt The amount ot cadmium adod (Fig 311 was monitored by use oran electronic autorancui couometer
Following addition ol cadmium the voifammeinc and coulometric scans indicated that only a small fraction ol the known cadi-uum content inside the void space oi the packed-bed electrode was being measured- After removal of the cell assembly examination showed flat the glassy carbon contact rod had somehow fractured possibly due to excessive pressure from the matin stainless steel contact rod and resumed in lo of elecshytrical contact with the packe-i-Sed electrod
The -ell assembly was then redesigned and rebuilt to permit electrical contact to be maintained without undue pressure and to allow accurate measurement of the working volume of the packed-bed electrode The new design was similar to that of the previous cell except that the upper fritted quartz disk was permashynently sealed (o the surrounding quart sheath A small hole in (he center of the disk permitted loading of the daisy carbon spheres into the electrode assembly and provided accurate positioning of the glassy carbon con-act rod into ihe bed Prior to loading of the spheres
the volume contained between the porous quart disks was measured with mercury
Some voltammetric and coulometric scans in the presshyence oi cadmium ions are shown in Fig- 3 1 As in preshyvious studies in aqueous media with the packed-bed electrode2 more accurate analytical results were obtained on Ihe anodic half cycle (stripping) than on bulli cathodic half cycle (deposition) Approximately 40 mC of cadmium was estimated to be within the packed-bed electrode The coulometric results shown in Fig 31 n quite consistent with this value Thus it is possible knowing the geometry raquof a packed-bed electrode to estimate the response and sensitivity within reasonable limits (the accuracy oi estimation depends upon void fraction the accuracy of the volume measurement and other factors) Repeated scans over a period of many days showed good reproducibility and also established that diffusion through the quart frits during the time of measurement (only a few minuus) has very little effect on the results
12 I I R Bronstcin and I- A Posey Otrm Mr Amu Proxr Rep May raquo IW ORiSI 4976 pp 1119 I I
Another cell was pocked with jOOp-dum glassy carbon spheres and used to obtain the results shown m Fig 32- In this case a quantity of amp ions had been anodued into the melt in a manner ssraiar to that used for cadmium- At the time of these measurements the same melt had been in use for many weeks Fig 32 shows voiiammetnc and couloroetric anodic stripping curves in the vicinity ot the anodic peak for stripping oi bismuth which had previously been deposited on the imemal surfaces of the electrode during the cathodic ^ii cycle In agreement with observations of others we found that volatility of BiCl precluded close correshyspondence between added and observed quantities of bismuth and that the bismuth peak decreased steadily with time The appearance of the bismuth peak suggests that possibly some alloying of bismuth with the cadshymium look place
Other expeiiments on bismuth reduction and stripshyping will be carried out in the future in which cadmium used for calibration of the ceil sysreni is absent In addition the present apparatus wiL be used lto study the electrochemistry oi lithium teiluride in the UC1-KC1 euieciic Observations on lb tellurium system in the chloride melt may be useful in interpretation of tellushyrium behavior in later studies with MSBR fuel salt The
CWV-3WG 75 -Z99
TEMPERATURE 392-C if REFERENCE ELECTRODE laquoflaquolaquoCMraquo4r) pound
GLASSY CARSON SPHERE OMMETER -200raquogtCfm
04 03 02 01 00 -Ol -02 - 0 3 - 0 -05 -06 ELECTROOC POTENTIAL (rtAflAflCO (bullraquo()
F J2 Linear-sweep anodic stripping votUmmetry and coglometry of hianiirh efecfrodepooted onto a packed-bed electrode of gUscy carbon spheres Solid lines experimental current-potential and charge-potential curvet in ihe region of (he rmmuh stripping peak dashed lines estimated background charging curves
34
cajxabilify of the packed-bed electrode ot ciasv carbon tfetctci tot monitoring eieciroactrve species n molten sail has hem shown ugt be sattgttactor Consequently p bull aw now under wa raquo design jpd fabrKation ot cells and appaiaius lor sestmc the electrode system in mxten fluoride media induduw MSBR fuel salt- In Msmufh-coatauung fluoride metis whether bismuth iraquo present as Bt or LijBtor both it should be possible 10 identifgt and determine ihe quantities of each species The packed-bed electrode offer hope ut removin as well as monitoring dissolved bismuth m the fuel sail which may be present as a result of the reductive extracshytion process for removal ot fission products
iS FUEL SALT-COOLANT SALT INTERACTION STUDIES
A D Keimers D t Ilealherly
In the alternate coolant evaluation1 several areas of potential concern were defined with regard to the applishycability o( the conceptual design coolant salt | a B F 4 -NaF (gt2-K mole ^ l | for MSBRs These centered primarshyily arogtmd events associated with off-design transient conditions particularly primary heal exchanger leaks which would allow imermixing of fuel salt and coolant salt If coolant salt leaked into the fuel salt the quanshytity and rate of evolution of BF j gas from reaction lt 11
N B F 4 l d raquo o l j U M - B F l g gt bull N a F i d gt u e ^ lt I
would determine the transient pressure surges to be enshycountered in the heat exchancer and reactor Also preshyvious work 1 4 indicated a substantial redistribution of the ions LT Na Be F and BFlaquo~ between the resultshying immiscible two-phase system formed on mixing Lj BeFlaquo and NaBF 4 The solubilities of UF 4 andThF 4
have not been measured in such systems thus the disshytribution of uranium and thorium between such phases and the resulting concentrations are unknown In addishytion if oxide species were present in the coolant salt either deliberately added to aid in tritium trapping or inadvertently present due to steam leaks in the steam-raising system the precipitation of UO2 following mixshying of an oxide-containing coolant sail with fuel salt has not been investigated Therefore a series of experiments were carried out to investigate these areas
I J A D Kelmirs tl al Committer Report hvaluaiion of Alternate Secondary land Tertiary) Coolants for the Molten-Salt Breeder Reactor (in preparation)
14 V K Bamberger C h Baelaquo Jr J P Young and C S Shew MSR Program Semiannu Prop Rep reh 20 I96H ORNL-4254 pp 171 73
The experimental apparatus consisted ot a a u i u vessel heated by a quuri furnace so thai the raquoraquoraquottTvr of the resukmc phases ouid be observed at temp mure and measured with a cathetomrter The quari vessel extended up out of ihe furnace and was closed with an O-itne titling and end plate A nickci stilting shaft driven bgt a constant -speed dc r-fcgtllaquogtlaquo peneiiated the end plate and during live tests was dnven at a speed adequate 10 stir the two phases without appreciable vtsibW dispersion Access for sample fillet slicks was provided through the end plate as was done also for ihe argon inlet and exit lines A very low argon flow main-tamed an inert atmosphere over ihe melt during ihe experiment
Predetermined weights of fuel salt (nominal composishytion LiF-BeF ThF-lF 4 (Mfc-117-03 mole^raquo | and coolant salt |nominal composition NaBF4-NaF (2- mole ltl| were placed in the quart vessel and rapidly healed lo 550 C Bubbles of gas could be observed due to BF) generation via reaction I I I as soon as the coiilani sail melted during the heat up period When the temperature reached 550 ( counted as time zero stirshyring was initiated The volume ol the phases was periodshyically determined and filter-stick samples were taken at 30- or dO-rrun inieials
The reaction between the fuel salt and coolant sail proceeded slowly approximately 30 to raquo0 min was required to complete the visible evolution of BF 3 gas at 550degC When the initial coolant salt content was 20 wt or less of the total material no omlant salt phase remained after approximately I hr All the NaF disshysolved in the fuel salt phase and all the BF gas left the reaction vessel With larger initial weights of coolant salt up to 50 wt gt a small residual volume of coolant salt phase could be observed after I to 3 hr Severe corrosion of the quartz reaction vessel occurred at the interface between the coolant salt phase and the argon cover gas in the experiments with the larger initial weights of coolant salt presumably due to attack of the quartz by BFj via a reaction such as
2BF(g) + VjSiOjfc)- SiF4fggt + fcOjfd) (2)
In experimenis 6 and 7 holes were corroded completely through the vessel wall and the surface of the stirred molten coolant salt phase was exposed to air for I to 2 hr at 550degC
In most of the experiments samples of the fuel-salt phase were withdrawn at intervals of 1 2 3 and 4 hr Samples were also taken after the conclusion of the experiment after the melt had cooled to room temperashyture the quartz vessel was broken away from the solid salt All these samples gave essentially identical analyti-
Tabic 32 Compmiliun of fuel-Mil pliiH- ami cnulani-aalt phatv aflci contact al 550 C
h vpcrimenl No
Initiil imvlmc iwt raquo
Hu-I salt Coolant i lr
100 9( Ho 7l) 61) 51)
o II) o 3raquo 41) 51)
111
tgtHK 6 3 3 604 544 50H 44 0
I uclvill phase (mole gt
Nal IK-1 M i l I T
2 3 93
123 1911 63 366
17J 167 165 155 13 H9
NominaUomnoMUon l i l - -Bc l - -Th | - lt - l l (72-I6-I I7-03 mraquolc bull)
Nominal conipotttion Naltl- -Nul (92-K mole bull I
No coolant-suit phase remained
Not analyzed
115 105 106 |lgt9 96
ID4
I I I
I bull i2 IVH 94
Nal-
191 366 43 9
CoiiliiHvih phase IIIIOK- I
IWI l h l bdquo I T N i S i l
4 4 3H 3 9
ii IH n o l i (150 0 017 1)74 OlOH
lt 31 19
M 0 Nalll
lt5l IK 6 J 33
n 47
16 9
ft
36
cat values therefore tne fuel-salt phase analyse (Table 52) represent an average of 5 to 5 values Further supshyport lor the coateatun that react urns nrroHuK the fuel-salt phase were complete m feO mm c less t shewn In the plots of volume rs time in Fig3J The cootani-sai phase volume decreased raptdry tor about 30 mm due to reaction (1) thereafter the volume chance was slower presumably due to reaction i2h
It was irnpossibie to obtain coobnt-salt phase samples with the flier sticks both because the phase volume was small and the salt tended to dram out of the titer sticks Therefore aM coolant-salt phise analyses (Table 33) were from samples obtained after completion of the experiment and represent only smgje values
The analyses (Tabic 3 Jraquo show substantial redistribushytion of the ions Li Na and Be between the two phases Thorium and uranium exhibited low soiubiity in the coolant-sail phase Neither NaBF4 nor the oxyshygenated tluoroborate compound (represented as B 0 3
in the table) was soluble in the fuel-salt phase Fuel salt stirred in contact with a coolant-salt phase containing up to about 50 mole lt B0 3 showed no precipitation of LO Tht coolant phase compositions were ex-
onNL-DWG 75-raquo3748
rlX Claquo
1 0 -
X T
Cootant Solf Phase -
20 40 60 80 TIME (mi)
100 120
Fit bullbull Votame of coobnt-s-Jt phase and fad-nil phase vs fane in mixing experiment No 6 Initial mixture was 60 wi i fuel salt and 40 wt 1 coolant tall After heatiny lo 550deg C Mining was begun and tht depth of the two phase was periodishycally measured
F-laquo O
I n t u t i laquoaraquo4c bull
factual (bull4jac vilr Ml lt) ViM
l raquo bullbullbull 4gt gt- 5 bullbull bullraquo 4i M bullraquo bull bull bull
bullraquo 5 gtraquo MI 14
raquo - Na Nan bull Li bull ZBc bull 4Th bull 41 bull 4S
pressed (Table 33) m terms of the ternary system MF-B 0-NaBF 4 The compositions are dose to the glass-forming regions of the terra y phase diagram1 for the system NaF-BiC-NaBF where drscete comshypounds have not been established
The following pertinent observations can be made
1 The rate of evolution of BF gas on mixing was low- presumably the rate-limiting step is the transfer of NaF across the vflt-salt interface Thus in a reactor system with turbulent flow the release would be more rapid however these results are encouraging relative to MSBRs in that very rapid gas release reshysulting in significant pressure surges was not experishyenced
2 No tendency was observed for the fuel salt constitshyuents thorium or uranium to redistribute or to form more concentrated solutions or to precipitate folshylowing mixing of coolant salt into fuel salt These experiments do not yield information relative to mixing fuel salt into coolant salt since it was impossible to contain predominantly coolant-salt phase mixtures in quartz at 550C Thus the quesshytion of uranium (andor thorium) precipitation as lF4-NaF complexes as observed in an engineershying loop remains unresolved
3 Apparently an oxide species forms in the coolant-salt phase which is more stable than UOj since no LO-precipitation was observed Thus large amounts of oxygenated compounds could be added to the flu oroborate coolant salt for the purpose of sequesshytering tritium since leakage of such a coolant salt into the fuel salt would not lead to uranium or thorium precipitation
15 I Maya Sect 41 this report 16 H F McDuffie et al Assessment of Molten Salts ar
Intermediate Coolants for IWBRs ORNL-TM-2696 (Sept 3 1969) p 20
37
3 4 LATTICE AND FORMATION ENTHALHESOF FIR$T4tOlaquo TKANSmON^ETAL FLUORIDES
The pnmar bull purpose of (his inveMijpinw is to plaquoraquoraquowde a theoretical bans tor cnttcaiK evaluating the chermir-dynamic data thai raquoifl be blamed in an experimental program recently giiittled with Dmstuti ot Physical Research I undine In thf experureirraquo free enerpes of tormaiion will be deduced from emt measurements ot solid-etectriJyie caharuc ceHs The iirsi-roraquo transition rrcials include common sKucturai metab (Fe i Cgtraquo and other meuls iTi V) which may be used in fcaon or fusion reactors When these meuls are corroded or otherwise oxidized u fluoride media used m these resc-tors meial fluorides are formed reliable thermoshydynamic information for these compounds rs valuable in predicting their chemical behavior in the eactor system
For a metallic fluoride MFbdquo I where n is the valence of the metallic iongt the relationship between lattice enthalpy V and enthalpy ot formation is given by the equation
_y=-X Mgtbdquo nXly- ( I t
The lattice enthalpy is the best of the reaction
Mlggt + nV it) = MFbdquo(c) Craquo
at gtvl5 K The lattice enthalpy is very similar to the lattice energy the latter being someihat more diffishycult to obtain from experimental information 3Jr is the standard heat of formation of MFbdquo(c) A- is the standard enthalpy ltraquof formation at gtHl5 K of the gaseous cation and electrons ((gt formed from the crystalline metal
Hc)Mltg)+ gtlt( g) lt3gt
A-bull- is the standard enthalpy at ZW^K of a mole of gaseous fluoride ions formed from the ideal gases electrons and diatomic fluorine
V2F(sgt + ltr(g) - F (gf lt4gt
The enthalpies of formation for reactions lt3gt and (4gt are deduced mostly from atomic or molecular data Abdquo is obtained by summing the first ionization potentials of M and its enthalpy of sublimation and covcrling these quantities where necessary to 2ltraquolaquoI5 K values of bdquobull are given in Tables 34 and 35 The enthalpy of reaction (41 at gtXI5degKis ol24
Hmrraquotc bull Leal rrv-fcr
lt j l yi 5 4ilaquo 6 2 = si laquo2vraquo bull ltlaquo5i-Tiraquo bull 2 i v 5Slaquogt bullMgtC gt i2Wr 2raquoraquo i raquo f Crl I1 - 5 o5 3 6 - 5 Mnl 2ltgt5 4 - lf raquo 5 1 - I l-lt tif - 5 fc5s raquo - 5 C l - t5 - I f 2 laquo I V I 52 - bull raquo3 5 5 - bullltbull
t u t I I -bullbull 323 41 - - N nraquo I N Mraquo5 25
llaquolaquojgtltn rgt cntui-gt rmdashm lt I raquo-raquo- SRIgtS-IraquoS 34 bullgt cnhjlprs i ^uNinurn-n irin ret igt (atenve raquorjc prpjutraquogto encris sorretttrto irraquom elt 2 N BS Iivhnuai N-te 2gtMgt i llaquoI i ^iinucJ in this intetripibii ^NBS Icchnicjl V-ie bull-raquo 11t11 r V Rrufchiu tr j | iTim ThrmoJvn 6 bullbull( tgtraquo4( iXrrmrd tflaquom vgtlij ltal inkveil emf JJJ snmi in W H Sfcltr|[4i jnd J W Pjiicrv-n -laquoWtmmtm Mfidt 31 4 11 raquo-laquoraquo
f-IV-iF Thermhemif tehlt 2J e j NSRDS NBS 11111 I- Rudiicl jl J Oum rnt AifJ 1213 laquo11^1 NRS TcYhnhil tir raquobull lt fftSraquo
kcal per gram-ion it is based on Popps value 1 7 (34(H) eV) for the clectr gtn affinity of fluorine the dissociation energy lt 15 eV) measured by Chupka and Berkowit and the enthalpy difference of F (ideal gas) raquoraquo Hbdquo listed by lluiigren et al 1
The lattice enthalpies of the divalent fluorides arc listed in Table 34 and are plotted against atomic numshyber in Fig 34 The curious double hump has been intershypreted 2 0 in terms of ngand-field theory By this theory differences between actual values of A and those lying on a smooth curve drawn to fit the data of C a F Mnlj and ZnF are primarily due to ligand-field stabishylization energy (LFSfcl For (his series of compounds
bullThis rclaquoearcli in support of the MSRR Program wilt funded hy iho l-RIA Division of Physiiiil Research
17 II P Popp Xatitrforuh 22a 254 117) 18 W A ( hupka and J Berkowil Oiem Pint 54542h
ii nn 19 R Hullcren el al Selected ialun of the T)icrmltgt
dynamic Properties of the Elements p 177 American Society of Meials Metals Park Ohio 1973
2lraquo P (leor-e and tgt S McCliire p 381 in Progress in Inorganic Chrmisln vol I I- A Cotton ed Inieruience New York I W
M
750
_ TOO mdash
o E
x
690
6 2 0 -
I I I I I I I
I I I i I I I I I Cefj Stfj Traquoj V Crfj M Wgt laquo j MF 2 C 2 amp2 ddeg (T d 1 d J d 4 5 draquo d draquo draquo d
Fltg- 34 Lattice wlnaifiM of 3rf diva l l w i l u Solid circle (bull) are experimental aML catenated from Eq 11)error bars art uncertainties in ampH Open circle (-) are AftL mam Iwand-fldd stabilization energy Tnangks (A) arc aW^ minus both LFSE and Jahn-Tener energy Solid squares ltbull) were estishymated by adding LFSE plus 3 kcalmote as an empirical correcshytion to the smooth cone
the ligands are fluoride ions octahedrally coordinated (except for CaF 2 ) to the cation the ocuhedral field of fluoride ions acts to stabilize the splitting of tf-electron energy levels of the metal ions In a spherishycally symmetrical field the (-electron levels would be degenerate that is be at the same energy In Fig 34 the smooth curve drawn through for example N iF 2
represents the ampHt N i F 2 would have if the field of fluoride ions around the nickel cation were spherically symmetrical Octahedrally coordinated cations with unfilled half-filled or fully filled 2d orbitals will not have a ligand-field stabilization energy hence a smooth curve is drawn through CaF(tdeg) MnF(lt 5) and ZnF2(ltdeg)
Values of the LFSE can be deduced from optical spectra For FeF N i F 2 and CoFj subtraction of optically derived LFSE (Table 36) from bHL yields values (open circles in Fig 34) which are above the smooth curve by 2 to 3 kcalmole Similar LFSE subshytractions for CrF and CuF yield values (denoted by
laquoraquoraquo-raquo
Fhoodc iHf bullraquo- plusmnHL
ikai nMle) ileal mmfT l U a l motel
ScF 3941 2 1112 13224 r 2
w 33 1 3-$ 1222 1374 t 35 V F 2 9 S S I29raquo 1499 O F 277 US 14 I44S l 2 3 ^ I3gt l 143 t F e f bullSHi 13V4 1431 3 CoF mjf 1455-J 1457
N O W 1515-5 bull I 4 9 7 C - F ( 1 2 0 I S M 11520 lt - F 2 7 I3S9 143
bullban pomoMs from C E Moore SSKDS-NBS 34 (1970) earailgiri ot inlilmdashiliun from ref 19 catrnce state preparation energy correctnas from rcf 20-T N KeiaHani cf a l Cktm Tkrrmodrn t90 (1974s eO Kabascfccwsfci et at pp 3343S4 in JMrMftWpaf Iktmso-chematry 4th cd Pergamon Oxford England 197 Derived from toad garantc-cdl emf data gjien in W H Skdion and J W Patterson Less-Common Mruls 31 47 (1973) MBS Tetkmfl Note 270-4 (1969) fjASAF TkermochemicM Ttblts 2d ed NSRDS-NBS 37 (1971) Estanaied m this mvcstiplion hNBS TethmeitSote 270-3 (I96S)
open circles) above the smooth curve by 5 and 7 kcalmole respectively Both C I F J and CuF 2 (and to a lesser extent F e F 2 ) are known from crystal structure data to exhibit major tetragonal depai mdashres from octashyhedral coordination geometry This is attributed to the Jahn-Teller effect 2 which confers an additional stabilishyzation energy (Jahn-Teller energy is abbreviated herein as JTE) For CuF 2 and F e F 2 the JTE can be derived optically (Table 36) When LFSE and JTE are addi-tively applied to CuF 2 and C r F 2 the lattice enthalpy is overcorrected as is shown by the triangles in Fig 34
The methods outlined above can be applied to predict A t for V F 2 and T i F 2 Neither compound would be expected to have a significant JTE The formula used is
(5) Atfpound (kcalmole) = AHL bull LFSE + 3
where A V is the value for the compound lying on the smooth curve in Fig 34 The 3 kcalmole on the right-hand side of Eq (5) is an empirical correction reflecting
21 F A Cotton and C rmced Inortnic Chemistry 1972
Wilkinson pp 5deg0-93 in Ad 3rd rd Inter science New York
J9
OFSEk UTEXwl
IkvWt i lrgtH
H raquo T i 4 r |-ltU| OK laquo bullk-jl BRiic bull id lt
III ik^ai n-4ri
J S - l iraquoraquo I l raquo laquo n f i bulllt bull-
J- T i l bull I l Twr bull Mi t | 5 _ W 3raquo4
Jy gt f rlaquolaquoraquo laquo bull gt lt l | 4J6laquoI 5 laquo raquo l
J O K 1 laquobullbull l l raquo lt raquo I l f M a t l~4im bull bull bull I i
J- YtY 6raquogt - a I4i raquo -9
lt t raquo l 114ml lvi
J t raquo l Z l K I lb 5 Nil- lfc21 T I
J N i l 4 i m 54 lt u l I4UI0 4X4
J lt u K 4iKi 15 bull ~5t l raquo
JVjluc tivcn in D Orlkru Strut I RonJmg Berlin- 9 I 2gt 11raquo~Iraquo unlf otherwise m-JiutrJ l I SI minuinl very rlaquouchlgt i bullbull of Til- BiscJ ltgtn K N i F i l
Ksiirruted by jviumini lWgtq n ihj of Til-
Bjlaquod n iNH i gtVI Klinutrd hy Jraquorlaquonltcn mclhod |igtIX) jr r =1 -raquoltraquo cm --bullraquobullraquo Rouen t-Mirruic from JTI oi CuK Hiraquo-d n K( raquol ( ( Allen and K O Warren Struct laquorraquonWf SWw 9 Igtraquo7 nlaquogt| i
40
1550r
1500-
I I I I ORNL - DWG 75 - raquo3750 r I r
i i i I I l l I I ScF TFj VFj Crf MrF5 FeFj CoFj IWF CvF(ZnF)GaF ddeg d d d 1 (J4 d s dlaquo d 7 ltfraquo draquo d laquo
Flaquo 3 3 Lattice enthalpies of id trivalrnt Amides Solid bulltrclraquo laquoraquoi ace experimental plusmnH calculated from Eq (1gt error ban are published uncertainties in plusmnh Open circles ( ) are Af minus ligand-fteld stabilization energy Solid squares (bullgt are estimated by adding LFSF to the smooth curve
the difference between theoretical and thermochemical lattice enthalpies for NiF2 and CoF 2 The standard enthalpy of formation (Aygt for TiF2 and VF 2 is then obtained from Eq (1) and is listed in Table 34
Analogous considerations were applied to study AW for trivalent fluorides The data and results are preshysented in Table 35 and in Fig 35 The double-hump pattern of the data is evident in Fig 35 Subtraction of LFSE (given in Table 26) yields very satisfactory agreeshyment between theoretical and experimental lattice enthalpies of VF 3 and CrFj the agreement for TiF 3
(and for CoF 3 ) is less satisfactory As may be seen by the open circle below the curve in Fig 35 subtraction of LFSE from AHf overcorrects MnF 3 This is someshywhat surprising since MnF 3 with its 3d electronic configuration for Mn also has a azable JTE (Tabe 26) f the JTE were also subtracted the discrepancy from the smooth curve would be much greater In short the thermochemical data for MnF 3 are questionable
In estimating $HL and A for NiF 3 and CuF 3
(Table 35) only the LFSE was added to the spherically symmetrical values (ie smooth curve values) of ampHL In other words Eq (5) was applied without the empirishycal correction of 3 kcalmole
With regard to the A of the structural-metal fluoshyrides the theory as applied above suggests that there is little need to determine AVf for NiF 2 Moreover from the value of Afy of TiF 2 obtained in this study it is understandable why TiF 2 has never been prepared as a pure solid it can be easily shown that TiF 2 would readily disproportionate to TiF 3 and Ti However a more accurate experimental determination of A7 for TiFj would be desirable for both practical as well as theoretical reasons The same may be said for V F 2 VF 3 CrF2 CrF 3 FeF 2 and FeF 3
4 Gootint-Sak Chemistry A D Ketmers
41 CHEMISTRY OF SODIUM FLUOROBORATE
L Maya W R Cahill
The composition of the condensable fraction of the vapor piiase in equilibrium with molten fluoroborate can be defined by the system HuBF 4-HB0 2-H 20 as described in the previous report1 The work done durshying this report period was aimed at spectroscopic identishyfication of the molecular species present The B NMR as well as IR and Raman spectra of BF-2HjO FSFi(OHh- and of other intennediate compositions was obtained Dihydroxyfluoroboric acid (DHFBA) participates in exchange processes which could be desshycribed by the following equilibria
2HBF2(OH)2 = BF -H 2 0 + HBO
BFj-H 0+HBO = BF-2H 20 + HB0 2
The presence of HjBOj and HB02 was detected by 1R and Raman spectra and the pronounced broadening of the F and B NMR signals is an indication of exshychange processes The Raman spectrum of DHFBA indicates that this compound is a tetrahedral molecule Exchange processes were not detected for BF 3-2H 0 This compound appears to be stable at room tempera-twe The structural information derived from the Raman spectrum which identified BF 2H 2 0 as a
tetrahedral molecule agrees with the x-ray structural determination2 of this compound
Additional samples of condensate collected during the operation of the Coolant Salt Test Fanlity (CSTF) were analyzed (Table 41) Silicon is present because of attack on the glass trap used to collect the condensate Variations in the chemical composition of the samples can be interpreted as an indication that the condensed material is not a single molecular compound but rather a mixture formed by combination of the simpler gasshyeous species present gtn the system that is H 2 0 HF and BF The relatively high tritium content of these fractions should be noted Tritium is present in the system since some oi the Hastelloy N in the Icop was originally used in the MSRE The condensates show a tritium concentration factor of about I0 5 relative to the salt suggesting that fluoroborate coolant salt [NaBF4-NaF (92-8 mole )] may be sn effective means of concentrating and conveying tritium out of ikt system
Attempts were made to generate a condensable fracshytion in laboratory-scale experiments by heating oolant salt containing up to 200 ppm H as NaBFOH to 400degC in a closed system equipped with a coid finger The OH~ concentration in the salt decreased to 50 ppm and the composition of the condensate in a typical run was 532S H0BF 41483 (H0) 2SiF t anr 32^ free water found by difference The boron concentration in the condensed material did not reach as high a level as in
ORAL summer participant I L Maya MSR Program Semiannu Progr Rep Feb 28
VZ5 ORNL-5047p47 2 W B Barn and G B Carpenter Acta Ova 17 742
119641
TaMr 4 1 Analyses of CSTF trap coadeasttes
Sample Operation period Amount Chem
HOBF
ical compoMt ion Tritium content
imCifi Operation period Amount Chem
HOBF HBO SF
Tritium content imCifi
1 2 3 4
1972 11475 12475 31475 41575 41575 56lt75
Not avail 100 me
25 f 800 me
604 923 841 830
157 0
124 121
Not del 21 40 01
08 lo 30 r
57 34 06
Approximate amount Some of the material remained in the trap ^Difference(torn I0fr nH0 Given at a ranee Apparently more than OM simple was analysed for tritium content Data from A S Meyer and J M Dale Anal Chem [Mr An mi Pto0 Rep Jan 1974 ORNL-4930 p 28 The loop was not in operation between 12475 and 31475
41
42
the CSTF samples and there was considerable cor-bullosion Nevertheless these experiments showed a posshysible mechanism for the conversion of dissolved NaBFOH into a volatile fraction
An apparatus was assembled to measure he vapor d^rcity of BF i -2H G and related compounds at eleshyvated temperatures to determine the degree of dissociashytion of these materials This work tested the hypothesis that the condensable materials collected in the operashytion of the CSTF are completely dissociated at opershyating temperatures (+00~600C) and only combine to form more complex molecules in the colder parts of the system The procedure consists in measuring the presshysure developed in a closed system conuining a known amount of BF -2H 2 0 or DHFBA in order to establish the degree of dissociation according to the equilibrium described below
BF-2H 2 0 = BF+2HjO
At this time volumes in the apparatus have been detershymined and pressure determinations have been made using argon as a test gas Initial runs with BF 3 2H 2 0 indicate that this compound may be completely disshysociated at 400degC
Work on determining the oxide species present in molten fluoroborate is being continued and the survey1
of the system NaF NaBF4 BOj at 400 to 600degC has been extended to include IR and x-rav diffraction analyses in addition to physical and chemical observa-tiorii of the behavior of ^elected compositions The observations indicate that there are three main areas in the system
1 A region of compositions in which BFj is evolved This occurs with compositions having a deficiency in terms of equimolar ratios of NaF relative to the B 2Oj present
2 A region of compositions in which stable glasses are formed on cooling This corresponds to mixtures containing more than 33 mole B 2 Oj
3 A region in which crystalline phases and glasses coshyexist The tendency to form glasses on cooling decreases with decreasing B 2 0 j content
Usually coolant salt (NaBF4-NaF (92-8 mole )| contains relatively small amounts of oxide up to 1000 ppm and its composition lies within area 3 thus work has been directed toward characterizing the oxide species in this area At least two species were present one formed at the boundary of the glass area (high oxide content) and the other was NajBjFraquoOj which formed in compositions having NaFNaBF 4 B 2 0 mole ratios of 221 and 241 and was possibly present in
compositiors containing as little as 3 mole 7c BjOj Experiments at the 15 to 40 mole B Oj level approaching the coolant composition have been imshypeded by the relatively low sensitivity of IR and x-ray powder diffraction The difficulty with IR using the KBr pellet method arises from the fact that ~t thlaquoe oxide levels the only band not covered by BF 4~ absorptions is the one at 810 cm 1 This band has a relatively low absorptivity and it is common to NaBFOH NaiBzF0 N a B F t O and possibly other BOF compounds although the intensity and line shape are different for each compound A more certain IR identification can be made only when at least two topical bands can be identified (presently observable only at higher concentrations) as was the case in the identification of N a J B 3 F t O J at an oxide level correshysponding to 14 mole BJOJ Difficulties with x-ray diffraction arise from the low sensitivity of this techshynique coupled with the fact that the species have a tenshydency to form glasses Raman work on melts is being planned as the next step in this study
42 CORROSION OF STRUCTURAL ALLOYS BY FLUOROBORATES
S Cantor D E Heatherly B F Hitch
Alloys containing chromium in contact with molten NaBFlaquo-NaF would be expected to form a boride beshycause the reaction
(I + jr)Cr(c) + NaBF 4(d) + 2NaF(d)
= NaCrF(c)Cr xB(c) (I)
has a negative standad free-energy change (AG 0) At a temperature of 800degK ACj 0 o = - 1 0 kcal This value is based on an estimated standard free energy of formashytion (SGj) of NaCrF of -600 kcalmole In reaction (I) the exact value of x is unknown however AG of the more stable chromium borides (Cr2 B Cr5 Bj) is estishymated to be - 2 2 kcal per gram-atom of boron1 In nickel-base alloys reaction (I) may proceed more readily because of the probable exothermic nature of the reaction
CrTBfcgt +yNKalloy) = Cr(alloy) bull NiyBfc) (2)
3 O H KrikoriMl EstiirMion of HtJl Capacities and other Thermodynamic Properties of Refracsorv Borides UCRL-51043(1971)
4 O S GordkiN A S Dnbrovm O D Kokimkon and N ACherkovfun toys Chem 44431 (1972)
43
Assuming that AG of NiyB equals its enthalpy of formation AG for reaction (2) is about - 3 kcal per gram-atom of boron
An experiment to determine the extent of boride formation in the nickel-base alloys Hastelloy N (7 Cr) and Inconel 600 (15 Cr) has been in progress for sevshyeral months In this experiment mrtal specimens are equilibrated with NaBF4-NaF (92-8 mole ) at 640degC under an argon atmosphere and are periodically reshymoved washed free of salt using water and analyzed by spark-source mass spectrometry (SSMS) and less routinely by ion mkroprobe mass analysis (IMMA)-1
Analysts for boron on specimen surfaces by SSMS sugshygests some boride formation Hastelloy N specimens that had equilibrated for up to 129 days were found to contain 30 to 1000 ppm B Inconel 600 specimens conshytained 80 to 2000 ppm B Control specimens that had not been in contact with the molten salt showed 5 to 20 ppm when analyzed by SSMS Boron in Inconel 600 increased with equilibration time but with Hastelloy N the data were much more scattered and showed virshytually no time dependence
Several specimens analyzed by SSMS were also investishygated by IMMA Boron was present within the first few hundred monolayers of metal in inclusions also conshytaining sodium and fluorine in specimens of 2 Ti-modified Hastelloy N that had equilibrated for 72 days These contained 150 ppm B as determined by SSMS
5 Spark sowce mas specttomeuv and ion microprote mau analyss performed by die Analytical Chamstiy Dmson
The only plausible explanation seems to be that some NaBFlaquo remain on (or in) the metal surface despite the vashing (5 -10 nan in boiling water) intended to remove adhering traces of salt Some of the scatter in the boron analyses by SSMS is probably due to salt contamination of the metal surface Inconel 600 specishymens scanned by IMMA sholaquoed a similar pattern of surface inclusions contami^f B Na and F Unfortushynately IMMA does not provide quantitative analyses for these elements As yet the extent of boride formation cannot be quantified in either Hastelloy N or in Inconel 600 by a combination of SSMS and IMMA Probably however reactions (1) and (2) occur to a small extent boride is deposited at levels not greater than 500 ppm bullin Hastelloy N and not exceeding 1000 ppm on Incond 600 after four months of contact with molten NaBF44aF
IMMA was also used to obtain depth profiles of alloy constituents through about 5000 layers In control specimens elemental concentrations were uniform with depth far equilibrated Hastelloy N molybdenum was uniformly distributed throughout the depth explored but chrofiuuip and titanium concentrations increased linearly from the surface inward the iron concentration appeared to decrease slowly with depth Equilibrated Inconel 600 showed virtually no chromium in the fust 500 layers but chromium increased linearly in the next 4500 layers iron and nickel were uniform through the depth studied Thus IMMA indicates that chromium is selectively oxidized by NaBF -NaF (92-8 mole gt or by oxidants contained in this molten mixture
5 Development and Evaluation of Analytical Methods
A S Never
51 IN-LINE ANALYSIS OF MOLTEN MSBR FUEL
R F Apple D L Manning
B R Clark A S Mever
Corrosion test loops described previously have conshytinued operation with circulating reference fuel carrier salt LiF-BeF2ThF4 (72-16-12 mole ^ ) No additional loops hart been placed in operation during this reportshying period although several ire expected to begin opera-lion within the next few months
Measurements of the U-3 ratio in the forced conshyvection loop (FCL-2b) indicate a steady-state value of about 100 (Fig 51) This is somewhat lower2 than the
1 H E McCoy el al MSR Program Senumnu Progr Rep ug 31 1974 ORNL-50 I p 76
2 A S Meyn ec al VSt Program Semtcnnu Pro Rep Feb 28 1975 ORNL-5047 p 52
i MNL- om 75-1205
lt 1 1 1
3 V f mdash
amp amp amp
s 8 - i
bull bull
c I -J
m c
1 - i
-
2 bull bull
1
bull bull bull bull bull bull
raquo
bull bull bull
J _
bull bull
bull mdash
90 100 ELAMCO Tim
ISO 200 ltlaquobullraquoraquo)
apparent steady-state value obtained with the fluorid mixture LiF-BeF-ThF4 (68-20-12 mole 5gt indicating a less oxidizing melt The melt which started al a ratio of around 1000 reached this level via a redox process which presumably involves iactraquolaquoi ith the chromium in the walls of the vessel or in the specimens No atshytempts have yet been made to reoxidize the U3 in the melt by suitable additions of NiF or some other oxishydant It is interesting that the decrease to a steady-state value occurred after about 75 days ith a rapid deshycrease in the first 30 days Previous data from the expershyimental fuel showed2 a rather stable value near 10 for aoout 60 days until beryllium additions were made to force reduction of the U4
Some of oscillations in the data probably result from air contamination with subsequent oxidation when the loop was down This was most prominent with the experimental melt (68-20-12 mole S ) when the U43 ratio was substantially greater than the steady-state value reached at a later date
Ratios of U7U measured in the two thermal conshyvection loops NCL 21A and NCL 23 are summarized in Figs 5_2 and S3 respectively No unusual trend is apparent in the oxidation-state history of the fuel melt in NCL 21 A This loop was operated for about 240 days with Hasteiloy N corrosion specimens The curve shows a rather dramatic rise in the ratio whenever new specishymens are added This effect is attributed to additions of moisture and air which partially oxidize If3 A recover to lower ratios follows each increase in repetitive fashshyion
rj 1 t
OMl-Mt 79-OOSr 1 1 i
5 w i 1 V z
s Jr X
I bull 1
i 1 f
4 ^v bullw raquo bull
1
mdash bull
i i
bull bull
1 A- 1 100 190 ELAPSED TMfC
200 I )
290 300
FfcS1 Lmdash l gtFCL-2fc Fig 5J
NCL-m vmdashw
44
45
ORNL- DWG 75-12055 i i
1 i 1
2 bull 4 mdash 8s laquobull bullo
=3 i 3 bull copy
y i
bull bull bull bull I 1
i X bull bull bull
bull I I raquo IA raquo s s
bull bull bull bull bull bull
bull bull bull bulllt
laquo bull
I i 1 1
50 100 150 200 ELAPSED TIME (dors)
F4- 5-3- L LJ- ratios M rfcemal cowcctioa loop NCL-23
250
The U in the mdl in the Inconel 6CI loop NCL 23 wso aptdly retiuoed untS a V^iU ritio of around 40 was reached Since then the ratio has continued to decline reaching a relatively stable value near 5 The high level of chromium in the Inconcl 601 (23 wt lt) provides a sufficiently active reductant to reduce the U 4 more extensively than has been observed in Hastel-loy N loops therefore the greater U 3 concentration is not surprising
S2 TRITIUM ADDITION EXPERIMENTS IN THE COOLANT-SALT TECHNOLOGY FACUITY
R F Apple B R Clark A S Meyer
One major concern in the development of an MSBR is the release of tritium to the surroundings A potential method for limiting tritium release rates to acceptable levels involves trapping and removal of the tritium in I lie secondary coolant system This method must be tested before a complete understanding is possible of the manner by which tritium will be retained in an MSBR The present series of tritium addition experishyments involving sodium fluoroboraie will provide data on his method
The Coolant-Salt Technology Facility (CSTF) is being ltperated for testing the NaBF4-NaF eutectic mixture
with regard to its suitability as a oossible secondary coolant system In cooperation with loop engineers and technicians the Analytical Chemistry Group has been engaged in experiments to determine the fate and behavior of elemental tritium added directly to the cirshyculating salt to simulate at least in part the predicted transport o tritium into the coolant system via diffushysion through the primary heat exchanger This section describes the methodology and results of the first two experiments
About 80 mCi of tritium (diluted about 11000 with protium) was introduced into the salt stream over a period of about 11 hr beginning on July 17 Tritium concentrations were measured in the salt and the cover gas during the addition and for several days thereafter Salt samples were collected directly from the pump-bowl access port with a copper thimble covered with a copper frit One-gram samples of the cooled salt were diluted volumetrically and aliquots were mixed with a scintillation emulsion for beta counting
Cover-gas sampling has proven to be somewhat diffishycult At present a sidesfream is being sampled the diffishyculty arises from the passage of this stream through a nickel sampling line that is not completely inert chemishycally to cover-gas components Thus the amount of eleshymental tritium finally measured may not be an accurate
46
measure of tritium level within the loop gas system-More definitive experiments will require the use ot inert precious metals in the sampling system to remove doubt of chemical alteration of the cover-gas stream composishytion by the sampling system
The off-gis collection train consists of
1 a series of three water scrubber pretraps which serve to trap BFj and any other water-soluble compounds
2 a hot (400degC) copper oxide-tilted tube 3 a condensation trap to collect water formed in or
passing through the copper oxide 4 a liquid-nitrogen cold trap to remove the last trices
of water 5 a wet test meter to measure the volume of the iner
gas component of the cover gas that is helium
Results of the first injection experiment are summarized for the offgas (Table 51) and salt (TaWe 52)samples
Several days after operation had begun some liquid collected in the short glass section between the stopshycock used to divert the gas stream and the first trap in the analysis train The liquid was washed from the glass counted and found to contain about 60 jiCi of tritium This discovery clearly complicates the interpretation of previously collected samples since a large portion of total cover-gas tritium never reached the analysis train Furthermore no conclusion is possible regarding the chemical state of the tritium in the liquid The data suggest urn the concentration of elemental tritium
TabkSI TritimroMcM
iaCSTF
Tritium in ltas Time tpCimO
HOvluWe Fiemcnlai
17 1046 23 34 1305 07 12 1700 14 170 1 9 i i 1 93 2243 14 830
18 0100 32 420 0805 73 61 1000 44 71
19 1037 790 62 21 0905 1800 13
1325 50 13 22 0925 55 58 23 1303 85 29 24 1000 300 22 25 1315 340 26 28 1245 10 27
TaMrS2 TtitmmcoatcM mslaquot sMf tn rflrtfiol w i l i i jjiiwon mCSTF
Date July
Simple No
Time Tritium inCi (l
1 45 IKW 12 46 I3MS raquo 47 1512 35 4 1718 51 49 1930 9 j 50 2145 73 51 2321 H 2
1 52 1102 32 53 1912 20
laquo 54 9130 15 SMV 0952 75
21 55 1132 16 bullraquo2 56 1400 16 23 57 1330 20
increased in both the cover-gas and salt samples when the liquid was washed out between sampling periods I July 23-25)
A second tritium addition was made August 5 During this experiment no changes were made in the sampling apparatus but that region of the sampling train (desshycribed above) where liquid had been accumulating v as washed with each sample collection and counted sepashyrately The tritium found there was added to the water-soluble tritium measured in the pretraps Data for this experiment are summarized in Tables 53 and 54
An exhaustive analysis of the analytical and sampling aspects of these data is not warranted at this time since several variables which affect the addition sampling and the tritium losses have not yet been established A general discussion on the oehavior of tritium in the CSTF is given elsewhere1 The preliminary data are sufshyficiently encouraging to merit a more extensive investishygation into the extent and mechanism of tritium intershyaction with sal and cover-gas components Plans are now under way to monitor the tritium diffusion through a portion of the loop wall and to measure the level of active protons in the salt during addition of tritium A more intricate bull over-gas sampling device (a probe designed for the sart monitoring vessel or salt sample port) is being considered and may be fabricated if no simpler solution to the gas sampling problems can be found
3 Reference Sect 112 thn report
47
TaUeS3 Jiitmtm content in cover-gas amahs after jtvoad tritium aMinoa
mCSTF
Tricium m ja D l l e rime laquopCimll
(AlKWM) HOvi luhk HcmenuJ
5 0730 96 o5 ltmraquo HO 2 2 1130 22oo 10 1330 5JWgt 20 1530 7500 27 1830 13000 34 1920 13000 39 2100 12000 40 2315 9300 39
6 laquoP3n 9300 2 I I mi ltraquo) 16 1500 6500 i4 2000 4700 10
7 0940 3300 68 1415 2400 49
O93o ltraquo00 34 9 1450 1600 52 to W40 1300 2 1 1230 900 2 J 12 1010 570 11 13 1010 23o 0 15 inoo 1X2 lO llaquo iraquo935 76 05 21 1010 73 o j
TaMr 54 Tribmn content m sak s a f k i after moan H i r i mdash aaditioa m CSTT
Dale Sample Trunin iAapnU No m lad-e l
4 5 1313 nraquo 5 59 (1954 90
60 1145 21 61 1350 36 62 IS4ft 52 A3 IX4X 7 | 64 1932 6ft 65 2125 71 66 2335 50
6 67 lift in 30 6ft 157 19 A9 2 lraquo 16
7 To IOI4 9 5 71 152 ft 1
T 1 lolft 36 9 73 0916 4 2 I I 74 124ft 39 12 75 1035 14 13 76 I04K ^ 1
15 77 IOIO 14 I I I 7raquo IOIO 07 21 SMV IOA l3fW o5
5 3 ELECTOOANALYT1CAL STUDIES OF IRON II) IN MOLTEN LiF-BeFj-TkFlaquo
(72-16-12 MOLE 9tgt
D L Manning G Mamantov
Electroanalytical studies in molten fluorides have particular importance tor possible use as in-line analytishycal methods for molten-salt reactor streams Irani II) is a corrosion product present in molten-sIi reactor fuels We have previously carried out electrochemical s tud ies of i r on ( l l ) in molten LiF-NaF-KF ( 4 6 5 - 1 1 - 5 - 4 2 0 mole L iF -BeF 2 -Z rF 4
(696-254-50 mole ) and NaBFlaquo-NaF (92-8 mole ) Since the fuel solvent for the MSBR is a thorium-containing salt LiF-BeF ThF 4 (72-16-12 mole )it is of interest to conduct vortasnmetnc and chronopotenti-ometric studies of irondl) in this fuel solvent To detershymine concentration andor diffusion coefficients by linear sweep voliammetry it is necessary to know whether the product of the electrochemical reaction is soluble or insoluble The measurements discussed bdow were dace with this purpose in mind
A volummogram showing the reduction of ironOU Fe2 -raquo Fe at a gold electrode is shown in Fig 54 The circles represent the theoretical shape based on current functions tabulated by Nicholson and Sham for reversible wave where both the oxidized and reduced forms of the electroacthre species are soluble Thus even though Fe2 is reduced to the metal at gold the electrode reaction very closely approximates the soluble-product case apparently through the forrmtion of iron-gold surface alloys Further evidence that the Fe3 - Fe electrode reaction at gold conforms to the soluble product case is illustrated by the chronopotenti-ograms in Fig 55 The ratio of the forward to reverse transition limes ir^r) compares favorably with the
4 D L Mannmc Votcaninernx- Sradaroif Iron m Molten Lif-Nar--Kr fVermwwj Chen 6 2 2 7 i | 9 6 3 l
5 D I Mannine and G Manunfti X j p d San Voium-metric jnd CrirraquonnjgtotentKgtroeirraquo Sludirt igtf Iron in Molten H w r e k W tleclmtntl Oirm 7102 H964raquo
6 I I W Jenknu D I Manmae and O MamantoT Flec-irnde fotentiaU of Several Redlaquo Conple in Mollcn Hno-rnfeO Nmntchrm Sgth 1171 S3 119701
7 f R Clayton it HeciiochemK-jJ Slwbe in Molten Hnoride and Fraorntmrawv doctoral dtunalnm Imvenm of Tenncvee December 197) p ft2
ft A S Meyer et j l MSft Program WniMwn rop Rep Aug M 9 T 4 ORNl-laquo72Xp 44
9 R S Nicholson and I Sham Theory of Stationary FKtrode foiarocraphy J Oitm 3 7 0 7 I | 9 O I
48
QWNL-PWG 75-11275
I I I I I I I 150 tOO 5 0 0 - 5 0 -WO -150
POTENTIAL mV
Fy- 54 Stationary electrode watamumapam for e refacshytion of r V af gt faM electrode bull Broken UF-ueF-TnF Po-lentil axis B ltf - poundbullraquo-- Solid line is experimental Circles are theoretical dupe lor soluble product Iron) III concentration 0027 f electrode area 025 cm s lemperature 650 C
theoretical value of 3 (ret 10) for the soluble case which again points to the formation of surface alloys
The reduction of Fe2 at a pyrolytic graphite elecshytrode is illustrated by the vultammogram in Fig 56 and the chronopotentiograms shown in Fig 57 For the reversible deposition of an insoluble substance where n = 2 the voltammetrk Ep - pound p I = 303 mV at 650degC (ref II ) is in good agreement with the experimental value The chrooopotentiometric ratio (zyrr) is approxshyimately unity which also h indicative that Fe2 is reduced to metallic iron without any apparent interacshytion with the pyrotytic graphite and that all the iron is stripped from the electrode upon current reversal Therefore iron appears to be reversibly reduced to a soluble form at gold and to an insoluble material at pyrolytic graphite Thus the effect of electrode subshystrate on an electrochemical reaction is illustrated by this example
Chronopotentiograms for the reduction of Fe2 at an iridium electrode at 518 and 60DdegC are shown in Fig 5 8 The ratio at S I8degC is approximately unity and is 3 at 600 a C which is evidence that Fe1 reduction at iridium approximates the insoluble-species case (as with pyrotytk graphite) at SI8degC and the soluble-product case (as with gold) at 600degC This change in reduction behavior with temperature was not as pronounced at gold or at pyrolytic graphite
10 W H RimjnMn Oirowopoecmwiweiiic Transition Times and The Interpretation^W Chem 321514 (l0gt
11 C MwuMm D L Manm and J M Dale Reversshyible Drpnsitrxi of Metal on SoM Electrode by Voflammetry wnb Linearly Vary in Potential tlrctntml Ckem 9 253 tl9raquo5gt
The chronopotentiometric transition time r for an ekctroactiw species is given by the Sand equation 2
Average diffusion coefficients oi Fe2 in this melt evalushyated from the chronopotemiometric measurements by means of the Sand equation are approximately 42 X 1 0 80 X 10 and 15 X I0 5 o n 2 sec at 5IX 600 and 7O0degC respectively
54 VOLTAMMETRIC STUDIES OF TELLURIUM IN MOLTEN UF BeFThF 4
(72-16-12 MOLE )
D L Manning A S Meyer G Mamantov
Tellurium occurs in nuclear reactors as a fission prodshyuct and results in shallow intergranular cracking in structural metals and alloys i It is of interest to charshyacterize this substance electrodiemicaliy and ascertain the feasibility of in situ measurements by eiectroana-lytical means We previously14 carried out preliminary polarization measurements at a small tellurmin poc1
electrode in molten LiF-BeFj-ZrF to estaampbh (he potentials at which tellurium is oxidized and reduced in the molten fluoride environment These preliminary observations indicated that the electrode reactions are complex
For tellurium screening studies J R Reiser of the Metals and Ceramics Division fabricated an experishymental cell equipped with viewing ports and electrode ports for studying the stability of lithium teUuride LijTe in molten LiF-BeF-ThF4 The Li2Te was added as pellets following which voUammograms were reshycorded at gold and iridium electrodes
As LsTe was added to the melt the voliammograms became com4ex and are not yet completely undershystood For clarity pertinent observations at the iridium and gold electrodes are tabulated separately
1 Upon adding one 35-mg pellet of Li 2Te a reducshytion wave observed at 09 V vs the It quasueferencc electrode (ORE) disappeared- fhis wave is not yet
12 Pan Drlahay p 179 IT in Srw hturumenuH Mrlkodt m Eltcmxhrmotry htterscience New York 1964
I J H F McCoy Maiernh tor Salt-Tontammt Veswlsand Pipmt The Dtvrktpmtni mtd Vlaquoftn of Mollrn-Sali Rnclon OftNMH|2ll-ebnary 1975raquop 207
14 A S Meyer el j | JW hnmm Stmmmmi Prop Rrp Aug SI 1974 ORNL-5011 p 42
49 ORL-0G 7S-M277
OWEVT TiME CURRENT TIME n l tslaquocdraquo) (mA) (stcdw)
5 J Cyclic ibroouyofcplimi mdash i for w wountioa of bulloa j l l ) at a f o M efcinuiat Foraufciy of troMllt X15ttecti ode jrcj
identined The pellets did not melt or dissolve immedishyately Relics ot the pellets could be seen on the surface tor several days The windows of the viewpcris became coated with a bluish-fray deposit after a few days making viewing of the melt impossible The bluish-pay deposit is believed to be tellurium metal Tim indicates that tellurium species added as L i Te are not stable in the melt
2 Voltammograms recorded in molten LiF-BeF -ThFlaquo after additions ot Li Te did not reveal any waves that could be attributed to soluble dectroactive tellushyrium species Chemical analysis indicated lt5 ppm Te in the melt
3 Abo at an indium electrode a reduction wave was observed at 045 V vs the Ir ORE which was reasonshyably well defined at a scan rate of 002 V sec This wave is due to Cr J reduction the wave height increased upon adding CrF 2 but did not change upon adding LijTe At our normal scan rate of 01 V sec the wave was not well defined which explains in part why it was not positively identified on background scans that are norshymally recorded at 01 V sec
4 Voitammetrk waves indicative of leilunde firms on a gold electrode were observed However these waves disappeared after adding CrFj to the melt The volt-ammogramlt recorded at gold foflowmg the L i 2 Te addishytions became complex and the electrode reactions are not yet resolved
Additional volrammeirr measurements are planned whereby the supposedly more soluble and stable LtTe species will be added to the fuel melt
igt 2$ c m 2 temperature M W C potential io le wilts s Ir QRF
ORNL-DWG75-11276
l _ _ J I I 1 bull 0025 0 -0025 POTENTIAL V vs U ORE
fSA Statpmry laquofctWodc to l lmdashuupaw for IW rwJt-timi of imKl l ) at a bullyrorytic gray laquonlaquouut InwfoMe prodshyuct j i 650 ( ibrnretH-jl Kp hbdquoi - 05 mV me-i-uired 3 0 mV InHMlll ctgtiraquocenirjiHgtn n02 electrode jrea 01 o n
so
C---+C S -raquoTS
TMpound
F-f57 Cycfc Hraquoi-o-i--uli bull gt bull y mdash l fat HJC rofactioti of mottlU M raquo etcmgt4e area 01 cm 1 -cmr-mare 650C potcnlbi - o k tuli VI Ir URF
-TIME
FomuiilT ot irondh iraquoiraquo
vt
w i l l
Ffc SJ Cydm ctmomtfottmtia^mm for r jrra n2 a n 1 po-rnlnl laquoale raquonltlaquo v Ir QRF
ft- bull v -
r of MMdl ) at i Formality of -rolaquo(llgt OfMVrfcctr-i-Jr
Part 3 Materials Development H fe McCoy
The main thrust of the mateiials program is the develshyopment of a structural material for (he MSBR primary ciicuit which has adequate resistance to embrittlemeni by neutron irradmion and (o shallow intergranular attack by fission product penetration A modified Hasteiloy N conoining 2^ Ti has good resistance to irradiation embnukment however it remains to be shown that the alloy has sufficient resistance to shallow intergranular cracking Numerous laboratory tests are in progress (o answer (his important question It may be necessary 10 further modify (he alloy with rare-earth niobium or higher chromium additions (o impait heller resistance (gt shallow intergranular cracking
Laboratory programs (o study Hasteiloy N salt tellurium interactions are being established including the development of methods for exposing (est mat era Is under simulated reactor operating conditions Surface-analysis capabilities have oeen improved so that the reaction products in (he affected grain boundaries can be identified
The procurement of products from two commercial hea(s 1000 and 10000 lb I of 2^ Ti modified Hasielloy N continued All products except seamless
tubing were received and much experience was gained in (he fabrication of She new alloy The products will be used in all phases of (he materials program
The work on chemical processing materials is concenshytrated on graphite Capsule tests are in progress to study possible ch-mical interactions between graphite and bismuth-lithium solutions and to evaluate (he mechanishycal intrusion of these solutions into the graphite Since (he solubility of graphite in bismuth-lithium solutions appears to increase with increasing lithium concentrashytion a molybdenum thermal-convection loop that conshytained graphite specimens was run to study mass transshyfer in a Bi 25 Li solution
Some of the effort during this reporting period was expended in reestablishing test facilities Four thermal-convection loops are in operation in the new loop facility which will accommodate at least ten loops The mechanical properly and general test facility is partially operational but numerous test fixtures remain to be assembled and tests started An air lock has been added to the general test facility to make it more functional and plans were developed partially for further expanshysion of the faclity
51
(x Development of Modifk-d Ha^tclkn N H t McCoy
The purpose of this program is the development of metallic structural material)) for an MSBR The current emphasis is on the development of a material for the primary circuit which is the must important problem at present The material for the primary- circuit will be exposed to a modest thermal-neutron flux and to fuel salt that contains fission products It is believed that a modification ot standard Hasteiloy N will be a satisfacshytory material for this application An alloy that contains y1 Ti appears to adequately resist irradiation embrittle-ment but it remains to be demonstrated that the alloy satisfactorily resists shallow intergranuiar attack by the fission product tellurium Small additions of niobium and rare earths (eg cerium lanthanum) to the alloy abo improve the resistance to shallow intergranuiar cracking and likely will not reduce the beneficial effect of titanium in reducing neutron embrittlement Increasshying the chromium concentration from the present 7T to a value in the range of 12 to 15 may also be beneficial in preventing shallow intergranuiar attack Currently factors associated with production of the 2T Ti modified alloy in commercial quantities are being studied while smaller be-ts raquoe being nude o( Hasteiloy N containing both 2 r Ti and additions of niobium and rare earths These materials are being evaluated in several ways
Two large heats one 10000 lb and the other 8000 lb of the ya Ti modified alloy have been melted by a commercial vendor Product shapes including plate bar and wire have been obtained for use in several areas of the alloy development program Tubing is currently being produced by two independent routes The various product forms from the two large heats are being used to fabricate the salt-contacting portions of two forced-circulation loops
Laboratory methods for studying Hasteiloy N salt tellurium reactions are under development Methods must be developed for exposing candidate structural materials to simulated reactor operating conditions Tests are being run in which specimens are exposed at 700V to the low partial pressure of tellurium vapor in equilibrium with tellurium metal at J00C Other tests involve metal idlundes thai are either added to salt or scaled in cvjcualed quart vus lo provide a source of tellurium Several experimental alloys have been exshyposed lo tellurium and Die extent of inlergranular cMltking was evaluated meiallograpliically hssenli^l In tins prltgram jrc attentate technique for identifying
and characterizing the reaction products Several methods for the analysis of surface layers are under development
Materials that are found to resist shallow intcrcranuiai cracking in laboratory tests will he exposed laquobull fissioning salt in the Oak Ridge Research Reactor TeGen fueled-capsule series Three materials (standard llastelloy Inconel 601 and type 304 stainless steel) were exposed in this manner during the first TeGen experiment and their cracking tendencies closely parallel those noted in laboratory tests in which these materials were exposed to tellurium vapor Fuel pins for a second experiment have been filled with salt containing gt J U and will be irradiated in the i a future
61 DEVELOPMENT OF A MOLTEN-SALT TEST FACILITY
H E McCoy K W Boling B McNabb T K Roche J C Feltner
When the MSRP was terminated early in 1gt73 most of the equipment was reassigned to active programs When the MSRP was reactivated a year later the conshystruction and installation of new equipment were necesshysary before testing could begin Balding 2011 acquired by moving the occupants into a siraquoaller building had been used as a mechanical testing area about 12 years previously and was already equipped with emergency power and air conditioning However numengtus imshyprovements ~n the building were necessary in addition to lb acquisition and placement of new equipment Although all of the equipment is not operational this report will describe the status of the facility
The building is a two-story structure with mnninal dimensions of 50 X 50 It The first floor is quite thick and more suitable for -mourning vibration-sensiiive test equipment The second floor is of lighter capacity and is more useful for offices and supoort activities There are Iwo stairways leadmg lo the second floor hut all heavy-items must he brought up hv an overhead crane which extends from the west side of the building The west wall had deteriorated and large doors leading into llie first-floor experimental area made close temperature control almost impossible An air lock having the dimensions 10 X W ft was added lo the west side of the building which greatly increased the buildings usefulshyness for experimental work An inoperabk emerge- puwei geneialor located in a small building on the cast
52
5
side or Building 2011 Mas removed and the space renovated to provide a small shop area
Figure 61 is a photograph of the west side of Building 2011 The air lock which was added is visible on the left-lurid side The crane lor transposing materials to the second f raquo)t is alsigt shown Figure b2 is a view of tllaquoe north side (ias storage racks the new emergency power generator and tie small shop area I left sulci are evident
Figure raquo slows the equipment layout tor the first floor Some of the equipment in the southwest owne is used by the Analytical Chemistry Division lor detershymining the concentration of oxygen in liquid-metal samples A neutron generator is located beneath the salt storage ar a and is used for oxide activation analyses This analytical capability is quite unique and will likely be maintained The 14 lever-arm creep machines on the north side aie for testing in an air environment the 8 machines in ihe next row are for testing in a sail envishyronment the Ji machines in the next row are lor testing bulln an air envirorment Five strain cycle machines are located in the southeast corner and will operate with
test specimens in j salt enviroiiVrctii Ihe temperature and strain readout equipment is centrally located Sail storage tjclitie and salt charging equipment are used ut conjunctii-n with he tests operating in salt environshyment S
The equipment layout on the second floor is shown m Fig o4 Six deui-Ioad creep machines for testing in an air environment are located on the south wall- The tube-hurst equipment is only partially instiled and lis installation is not considered a high-prioritv item Tie annealing facility consists of en furnaces having vartcux temperature and envingtnmental capabilities A separate laboratory in the northwest corner is used for experishyments involving tellurium llasieiloy N interaciiiws The other facilities on the second floor include offices a data storage and processing area an instrument repair shop and general storage
A view of iome of the 22 lever-arm creep machines for testing in an JH ermionmeni is shown tn l-ig t o and a cl-raquoeup is shmn in Fig traquofraquo All of these machines are in operation The control cabinet shown in Fig istraquo contains tlie insirunteKistion for two creep machine-
Photo 22SC-7S
yen 61 Mollrft-SjH Teraquol Faculty (RmMiof 2011) (mm Ihc wta ale The newly tiHUtrihled Jit lock bulllaquo mi the left
54
iJf JhZ
^bullyr^J^f1
Fifc J Matae-S TMI Ficttljr (Baliinj 2911) fjoraquo the monk ate Feature of interei include the hop area on he tt~ left the emenBencv pronator on the kft o s Morale rack in the center and the newly constructed air lock on the ri$h
iraquo now
I if(raquoraquo Kquipmcm layout for the fir floor of BudJinf ifll I
55
Fig fc4 EqnpncM Iqroat for Ifce Miomd Onor of IwMMg 2011
The frame is of welded steel construction The levei arms have two sets of knife-edge pivots vgt that the weight on the back of the arm is multiplied by factors of 6 or 12 The pull rods and cxlcnsometcrs are curshyrently arranged for testing small specimens having gage dimensions 1 in long by lA in in diameter Pull rods and cxtcnsomctcrs lor larger specimens required for code testing) were also fabricated and can be used in the same machines
The specimen deformation can he determined by the dial gage or by a transducer which measures the deflecshytion of the dial gage shaft This transducer signal is conshyverted to a dc signal by the instrumentation in the bottom of the control cabinet cm the right (Fig 66) and is printed at another location The electronic circuit will also accommodate averaging transducers which will be used on more precise code work The instrumentashytion in the bottom of the control cabinet also has a module for measuring load from a load cell (not shown) which Tils in the bottom on (he creep machine The specimen is heated by a resistance-wound furnace
having a maximum Icmpcraturc capability of I200C The temperature is measured by up to four Chromel-Alumd plusmni accuracy) thermocouples treated at various positions on the ipcimcn gage kngth The signal fron one of these thermocouples is used by the Leeds and Northrup type KO proportioning controller to control the furnace temperature Switches within this unit activate an alarm shown in the upper left coiner of the control cabinet (Fig 66) if the temperature varies more than plusmn6degC from the control temperature This alarm unit activates a local light and bell alarm as well as causing an alarm t gt sound in the Shift Operations Office A second thermocouple is tied to an over temperature monitor (lower left side of control cabinet in Fig 66) This monitor is set 10 to I5degC above the control icmp-rraturc arid will interrupt power to the furnace The monitor must be reset manually The furnace is powered by a solid-slate power supply deshysigned by T Hulton of the Instrumentation and Conshytrols Division The unit incorporates a digital Variac which allows power settings of 0 10 25 SO 75 and
56
FlaquofcS i t f
100 of line voltage Power is pulsed through the unit as called for by the Leeds and Northrop controller
The six dead-load creep machines on the second floor are quite similar to the lever-arm creep machines just described As shown in Fig 6 7 these machines r e not in operation but the construction work is com| iete Since the load is applied directly to the bottom of the specimen the equipment is limited to specimen stresses of about 20000 psi However the frames can be conshyverted to the lever-arm type
Two salt environment creep machines are shown in Fig 68 The frames and control instrumentation are the same as for the air environment machines shown in Fig 66 The primary modification is a stress unit which can be immersed in salt Four load-bearing rods run from the bottom of the specimen to a flange near the top of the frame A rod from the lever arm passes through a seal in the flange to the top of the specimen Thus weights placed on the back of the lever arm place the specimen under tensile stress with the pulling force being transferred back to the flange No rods protrude
far below the bottom of the specimen and a salt conshytainer can easily slip over the stress unit This container seals against the underside of the flange Extensometer rods for measuring the strain pass through seals in the flange and strain can either be measured by a dial gage or a transducer A 4-rn-diam furnace fits over the salt container There arc several openings through the flange into the container for gas lirtes and ball valves for elecshytrochemical probes and for making additions to the salt Figure 6deg shows the salt-creep machine which is in sershyvice The salt raquoas transferred into the pot on the right in the salt preparation facility at Y-12 The transfer pot was placed in a furnace after which the transfer pot and the receiver vessel were heated to about 600degC before the salt was transferred by applying argon pressure to the transfer pot The temperature was stabilized in the creep chamber and a strejs was applied to the test specshyimen
One of the five strain-cycle units is shown in Fig 610 The test specimen is a l-in-OD tube with a reshyduced gage section having a length of I in The tube is
57
Flaquo 6A CkMtmp of two Mr-
welded in place and stressed by a rod which extends from the bottom of the specimen to a piston above the specimen The piston s moved by applying air pressure to either side resulting in a tensile or compressive force on the specimen The specimen assembly is immersed in salt while it is being stressed Extensomeier rods extend through the top flange to measure the strain These rods move transducers whose signals are recorded on the bottom instrument Switches inside the recorder can be
adjusted to change the stress from tensile to compresshysive when the strain reaches certain values The test can also be controlled on a time basis and the strain reshycorded Other modes of control are also possible This type of test is to study the rate of crack propagation through thin-walled tubes of varying composition in the presence of tellurium Installation of the equipment has been completed and test specimens are welded in place The tests will be started as manpower becomes avail-
raquo
ask Thear mdashaAntv war be ased for aftojr and ame precise work w be done oa MTS e war arm to be procared at a later dale
The anai jau colectioa station h oa fLe first lloor (Fig 611raquo The apper part of the cabiaet OR die left cuMtaatt snitches a aiaiial readoat aad a snaje poiat recorder lor leraperatnres from avow one-third of dK machiaes- The haak of Mriicbes ia the top of da rajfct-haad cabinet is for tetecrinc siraia rawerraquo for each
The sna-i tcadaajs faaa each auduae arc priated oat oa oae of the andtipoiai recorders A data
M I is located m the aaodfc of the right-I cabiaet Has rnsmMKM ltai print oat 100 points
oa dK designated Ireqneacy (asaaly I br) This is snf-fcieat capacity to print oat oae teaaperaiare aad one
for each piece of eqai|aarnt Two orjer bulleasnriag stations are located elsewhere on
dK first floor
Ffct7 General
59
The annealing arez sun the second floor I Fig 612) The two furnaces on the lower level have environmental control and are used for short-term anneals Eight other furnaces are used for long-term anneals hi which the samples are encapsnlated
Figure 613 shows a typical area in tne second-floor laboratory wed for tdurtum-HasteBoy N studies The
equipwunt includes a quartz encapsulation apparatus special gradient furnaces for annealing the capsules equipment for measunng gas-metal reaction rates and a general-purpose hood
The ttthe-burst equipment boa die second floor (Fig 614) There are nine test stations with each station
four test |
Fin 68 Close-up of two bullut-eiwuuinwtnt lever-arm creep machines The salt chamber on the left-hand machine seals apinst the horizontal flange and the furnace n raised a proportionate distance The temperature control and strain-measurement instrumentashytion are shown on both sides of the creep machines
60
Ffe 69 Lever-arm jd l imnunmiiit creep NMCJMMS in operation The ult chamber and furnace have been raised calt as transferred by argon pressure from the vessel on the right into the test chamber The cabinet on the left contains switching and temperature readout instrumentation for several creep machines
61
FlaquoIO ChwMip of a a l l ltngtJKinmml strain cycle machine M l amocMni intfnjmvntation The ieraquoi specimen is a l-m-diam lube welded on I he bottom I a rod and un ihe lop to a heavy-walled lube The rod passes through the lube and alicrnaling tensile and compressive stresses are impigtsed on the specimen by ihe actuator (piston-cylinder combination) The instrumentation is used to control and record the sires strain-time history
bull2
F g 61 I The cabmct on Ike left is one of smraf tartowt stations for limptnmn Chrontd-Alumel sensors from seYeral creep machines arc ran to this cabinet The switches make it possible to read each thermocouple individually on the digital unit at tlie lop of the cabinet One point at a lime can be recorded on the Azar recorder The cabinet on the right contains a data logging unit for recording strain and temperature on all the machines on the first door The three recorders in the bottoms of the two cabinets record strain data from a l machines
a
fit- 612 tkotopajk of hcsMltsaag facfvty The two lower furnaces have com roikd argon environments Fighl other furnaces (al noi visible) have air environments and are used for long-lime anneals
64
Fig raquo13- Typical vie of geaoat-aeaaot used to dean salt from jpuiawai tested in a l t amroameati
ettl reactroas The hood on the left is
rraquoraquoiraquo wraquo-raquo
F|g 614 General view of tube-burst testing eqaipment asai lo stress tabular spec ant ni by internal pre ware The front paneli contain only (he pressure-related equipment The furnaces where the test specimens ate located and their associated control instrumentation are behind the pressure panels
65
by a pump with a wear pressure of 14400 pa The pump aad the ass-xiated reservoir cylinders have beea approved for opcratioa aad the iaawaaal test suborn w2l be pat irt semcr oa c ow-pnonty basis
Iiiaatdun efiptens wtfJ be placed oa geinaf a l equipment iato operatioa Longer-term objectives war iadade prucaremeat aad iastaaatioa of an MTS fatigue machine aad possible expansion of the fast floor to accooaaodaie additioaal creep machines
t J PROOJKEMENT AND FAMUCATION OF EXHHMENTAL ALLOYS
T K Roche R E McDonald B McNabb J C Fehaer
bullUI hadwit iaaHeatsafraquo Ti M I T I I I M H I I J N
One of the more promising alloys at present for the primary circuit of an MSBR is 25 Ti modified Hasidloy N Progress has been made in the scale-up of this alloy with the production of two large heats one 10000 lb and the other 8000 lb by a commercial vendor The analysis of the heats was reported preshyviously These heals were used to establish processing parameters for producing plate bar and wire and more recently emphasis has been placed on processing seamshyless tubing Mill products from these heats are being tesed in the general alloy development program and used in the construction of two forced-circulation loops for studying the compatibility of the alloy with fuel salt
As reported previously several fabrication problems were encountered with the first heat (heat 2810-4-7901 or 74-901 10000 lb) in that it was prone to cracking during hot-working operations particularly during hot rolling of the plate However with the aid of Glcebli evaluation tests which defined the hot-working temperashyture range of the heat to be between 1090 and I I77degC plate products were successfully rolled A second prob-leri was the susceptibility of the heat to cracking during the annealing treatment following cold drawing in the production of bar and wire products This problem was partially solved by cither flexing the drawn product in straightening equipment prior to aiiiltjHijat 1 7degC or by lowering the intermediate annealing temperature to nidegc
Because a considerable amount of the first heat wis consumed in establishing processing parameters a
I T K Roche B McNabb and I C FeltrwrMSK Proshygram Semmrmu Pmgr Rep Feb 2 1975 ORNL-5047 pp 60 63
second heal was prodaced (hat 8918-5-7421 or 7S42I 8000 lb) for coavcrsioa to tatang bar and wire The bot-forgaag behavior of das heat was qaite good as confirmed by Cfeebie data which showed a very broad bot-workmg temperature range of 930 to 12600 Approximately one-half of das heat was forged and tamed to 4 Jna-diara bar for coaversion to seamshyless tubmg by the vendor Akoa forged bar 4 X 4 X 6 0 in was produced for conversion so tabiag by an altershynate route The balance of draquoe heat was convened to the folounac products which bat been received o-m-diam bar (630 lb) 05-ai-diaai bar (292 ft) 0J12-in-disn bar (996 ft) 0125-av-diaai wire (405 b) and 0-094-in-diam wire (338 lb)
For making products in the range ^-ia-diam bar through -in--diam wire forged bar was hot roBed to about I-ia-diam bar and an attempt was nude to conshyvert this material by cold drawing to final sizes with intermediate annealing treatments This routing proved satisfactory unti a H^meter of 0J95 in was reached but annealing cracks as experienced with heat 74-901 were encountered to some degree during processing of the 03l2-tn-diam bar and the wire products For example during a run involving about 850 lb of stock about 2 of the product was lost due to cracking during annealing after the material was drawn from 0J95 in in diameter to 0 J i 2 in in diameter The bar was mechanishycally flexed prior to annealing a technique used to minimize cracking in material from the first production heat of the alloy (heat 74-901) The annealing cracks were observed to run parallel to the longitudinal axis of the bar Examination of a transverse section of the cracked 0Jl2-in-diam stock showed that the cracks were intergranular in nature and up to 0065 in deep in the section examined (Fig 615)
It has been possible to reproduce the annealing crack phenomenon on a laboratory scale Samples of 05-in-d am bar of each of the two production heats were coiJ drawn lo 0395 in in diameter (37 reducshytion) and annealed at I I77degC Heat 74-901 developed longitudinal cracks heat 75-421 did not These results are consistent with the vendors observation that heat 74-901 is more susceptible to the cracking problem Since the cracking can be reproduced or a laboratory scale it may be possible to more fully characterize the problem and define fabrication parameters necessary for its prevention
Of the two routes being pursued for the procurement of seamless tubing one by the commercial vendor inshyvolves trepanning forged and turned bar slock to45-in OD X 05-in wall cold tube reducing (or pilgering) the material in three steps to 20-in OD X 0187-ir wall
66
m
o p A
-O o_ b
o x t o 1 yraquo2
o o-
8-o
yen $ H m d i raquo cocks iraquo ttJU-aL-MMi bat of 2raquo T t - a o M M KasMftty N (hut 75-421) Bar was coM drawn 37- and ameafcd a( I065C Ftdicd with (dyccm rrpa 50x
followed by cold drawing to final sues of 10- 075- 05- and 0J77-in OD X OJ035- to OX)72-in wall This route for tubing production depends upon the efforts of two other vendors one for trepanning the bar and the other for drawing to tlnal sizes The trepanning operashytion has been competed and resulted in six tube holshylows each approximately 6 ft long Each of these pieces was processed through the first tube reducing pass to a 375-in OD X OJ75-in wall (3675 reduction) with no difficulty From this point work was confined to one tube hollow to determine its response to in-process annealing at I I 2 I degC and water quenching followed by further tube reduction Annealing of the hollow beshytween each tube reducing operation was preceded by the annealing of a sample which was then liquid penetrant inspected to determine any evidence of crackshying With this procedure the hollow was taken through the remaining two tube reducing steps and three annealshying treatments with no major problems A few shallow surface flaws did develop but these were readily condishytioned from the product Therefore on hand at present is approximately 24 ft of 20-in-OD X OI87-in-wall stock which will be scheduled with the redraw vendor for processing to final sizes The lube reduction of the remaining five hollows will also proceed
The second route for obtaining seamless tubing inshyvolves hot extrusion of tube shells at ORNL followed by cold drawing to size by an outside source Starting stock was the forged bar of the alloy 4 X 4 X 60 in (Fig 616) The bar was machined into six billets each of which measured 3deg50 in in OD by approximately 95 in long and had a 45 tapered nose for extrusion out of a 4060-in-diam press container through a conical die Two of the billets were drilled 0812 in in ID and four were drilled 10 in in ID to accommodate a mandrel and to allow for a slight variation in extrusion ratio A glass coating which was molten at the extrushysion temperature was applied to the billets and served as the primary lubricant Additional lubrication was provided by Fisk-604 grease that was applied to the tooling Five of the billets were extruded at 1200degC and one at I250degC Low extrusion rales (ram speeds) were used to prevent a sufficiently large temperature increase that the incipient meiing temperature of the alloy would be exceeded otherwise serious cracking could result This problem was encountered during the develshyopment of standard Hastelloy N but was solved by conshytrol of extrusion rate
The results of extruding the l7r Ti modified HaMclloy N billets in the order performed are pre-
67
sensed in Table ftI Fur the first three tube blanks produced extrusions lottf 104 and 1605) die low rale of extrusion caused mandrel taawre d w to ecev I I K healing vf the tooling However ike length of tube blanks obtained with various extrusion ratios and ram speeds suggested that the combination of tooling used lor extrustoR 1604 (extrusion ratio of deg41) with an extrusion speed approximaidy equal to that of extrushysion 1605 125 m sec) should produce a complete tube blank This was die case for extrusions I60K and I6QN In an attempt to reduce the force required to make these extrusions the final tube blank lexirusion 1611)
was extruded a a slightly higher temperature 12501 A rather long length ol good extrusion was obtamed but mandrel fanure agam occulted due to the low extrushysion speed
Visual inspectioK of die tube blanks showed die OO surfaces to be quite good as must rated m Hg 617 wfwch shows the lesdmg end of extrusions I60K and 160V O i dae other hand boroocopic examination ol the IDs by die outside vendor performing the redraw operation revealed flaws winch were subsequently removed by gun iriEing These flaws shown typically in Fig 618 a=e believed tc be caused by inadequate lubn-
m-n
Flaquo l seamless tuctnc
H r ( lt 4 gt M u i r K T i - i N (fecal 75-42 h Slock for ramm bwVt o produce
Tafefc-tl snd raridof n w Mask cxtrwOTMvav2t Timdashnodinnl Nattdby N (beat OTI8-5-Mll|(B
Fxtruuon Die diameter i in i
1603
1604
1605
i475
1625
1475
Mandrel dumcrrr
in)
K IruMt-n Rjm speed ratio (in laquo i i
Force ttonsi
Maximum Running itesuils
0813
JO
0812
114
94 I
1041
15
15
25
1230 l l l l Good 0D surface 22 m of tube blank extrusion before mandrel fadure
l6igt 1100 Good OD surface 45 in of tube Hank extrusion before mandrel fadure
12f0 12i Good Oigt suriacc 4raquo in of rube blank extrusiim before mandrel failure
1607 1625 10 941 Stalled operational error
1608 1625 10 941 36 12911 1290 Good Ol) surface 70 in lube Mank extrusion
1609 1625 10 941 36 1290 i290 Good OIgt surface 70 in tube blank extrusion
1611 1625 10 941 10 1000 900 Repeal of extrusion 1607 jtood OD surface 55 in of lube Hank extrusion before mandrel failure
Notes Container diam 4060 in hxtrunon temp 1200deg (except extrusion 1611 at I250C Lubrication class on billets f-isk-604 jcrease on tooling
68
nraquolaquo15M-79
M06
760 Fig 617 Tibr hlanfc exuasjom of 2 Ti-wdifM I fuWuj N (heal 75-421 These are ihc leading ends or the two extrusion
and were photographed in the as-extruded condition
O O-
O O-
O ho d
Fig 618 Typical defects M I the made diameter of extruded lobe Wanks o 7 Tr-modifod rlartcBoy N (heat 75-421) Longtludinal section Ffched wrlh glyceria rejtia tOOx
69
cation during extrusion Therefore several additional extrusions are planned to test ihis assumption and to evaluate other lubricants The bilets will be prepared from the 6-in-diam bar fabricated from the same comshymercial heat used for the previous bitten
The products of the six extrusions (Table 61) were sent to an outside vendor for redrawing to finished tubing More effort was required than anticipated due to several factors the conditioning required to dean up the surfaces of the extrusions experimentation with both plug and rod drawing techniques to establish a workable processing schedule and more frequent and longer intermediate annealing treatments than anticishypated for the alloy The vendor believes that a satisfacshytory drawing schedule has been developed and is proshyceeding with processing of the remaining extrusions The vendors preferred process involves rod drawing and sinking operations requiring about 18 to 2ttS deformashytion per pass with intermediate annealing treatments at I I77C followed by water quenching Quality control steps after each process step irJ-de light etching folshylowed by visual inspection of the OD and boroscopk inspection of the ID for defects It is believed that the yield of tubing from the redrawn ORNL extrusions will be sufficient for at least one of the two forced-circulation loops now under construction
A 6-tt length of cold-worked 075 m-OD X 0072-in-wall tubing was received as product from the development work required to establish a drawing schedule The tubing is being evaluated by nondestrucshytive techniques Liquid-peneirant inspection of the OD showed no defects Silicone rubber replication together with radiographic inspection indicated the presence of relatively shallow crackiike indications on the I D over a 4-ft length Meiallographic examination of a small sample from the did of the 6-ft section showed the defects to be J maximum of 0028 in deep The tube will be annealed and inspection will be repealed including examination by an eddy-current technique In view of the number of process variations to which the tube was subjected in developing a drawing schedule the quality of the OD and that of portions of the ID is encouraging
622 Seimprodlaquoctiontfeatsof2ri-Modified Hastdoy N CoiriaMng Niobium
To provide stock for a more complete characterizashytion of niobiunviiianium-modified Hastelloy N eight SO-lb heals and one 2S0C lb heat (Table 62) are being prepared by a commercial endor Niobium additions lo the 27 Ti modified Hasieloy N base arc of interest for enhancing resistance to tellurium embritilemcnt and
Bve Ni-12T Mo-7laquoS Cr-21 Ti-007 C
l ov Addition of the jadiciied rirMear 4) Heat
laquoze lltraquo
Jmr re Si Ma Nb
Heat laquoze lltraquo
i 10 01 02 085 -115 2500 10 01 02 04 06 50 IO 01 02 135 -165 50 10 01 02 18-22 50
30 50 01 02 085 11$ 50 10 01 - 02 02 085-115 50 10 01 02 05 085 115 50
8 30 50 01 02 02 -05 085-115 50 bull 10 01 02 085 115 50
Indrndnl nines denote maxnnom coaceMnrioa
niobium levels between 05 and 2 wt It w i l be investishygated Ir addition the compositions of four of the alloys were chosen to investigate different levels of the residual elements Fe Mn and Si These results will be important because of the beneficial effects of the residshyual elements upon oxidation resistance and will allow greater latitude in scrap recycle
The nine alloys have been melted and will be procshyessed lo products in the near future The eight 504b melts will be forged and rolled to ^-in-thkk plate approximately 4 in wide This material will be used for voidability salt corrosion tellurium compatibility and mechanic property tests The 2500-lb heat will be conshyverted to t |raquo- V - and | k-in-diam bar products and to a 4 X 4 in round-cornered square bar About half the material will he retained in the last form lo allow future capability for producing additional products of sheet bar and tubing
6 J WELDAMLITY OF COMMERCIAL ALLOYS OF MODIFIED HASTELLOY N
B McNabb H E McCoy T K Roche
Welding at ORNL is generally performed in accordshyance with Section IX of the ASME Boiler and Pressure Vessel Code2 Basically this requires that a procedure for welding a material (or class of similar materials) be developed and that welders demonstrate that they are qualified to weld by the procedure The procedure must
2 ASMt BoHer and Pressure Vessel Code Section IX Qutt ifuvxm Standard for Welding and Braimg Procedures Weldm Bnm end Welding and Brtittg Operators American Society of Mechanical Engineers New Ywk 1974
70
be a written document including die essential variables associated with making the weld and must be backed by test reports including bend and tensile tests which show that the weld is sound A welder can then be qualified to use die procedure by making a weld which is subshyjected to bend tests to show that it is sound This is a very suupKfied view of the process used to develop and maintain high welding standards and the ASME Boiler and Pressure Vessel Code Section IX 2 should be conshysulted for more detal The Plant and Equipment Divishysion main tains a weld test shop under the supervision of D R Frizzed to implement the process and this shop is frequently assisted by the Inspection Engineering Department
Procedures were previously developed for joining HasteHoy N to Hastdloy N (WPS-1402) and Hastettoy N to die austemtk stainless steels (WPS-2604) but it was necessary to demonstrate whether these procedures apply equally weO to 2 Ti-modified HasteBoy N Therefore K-n-thkk test plates of 2 Ti-modified Hastelloy N (vendors heat 2810-4-7901 designated ORNL heat 74-901) were prepared and welded as folshylows autogenous welds with 74-901 welJ wire welds with 2 Ti-modified Hastelloy N weld wire (vendors heat 8918-5-7421 designated ORNL heat 75-421 welds to standard Hastelloy N heat Nl5075 with 2 Ti-modified Hastdloy N heat 75-421 weld wire and welds of type 304 stainless steel heat 18024 with Inco 82T heat NX59I38-D wdd wire Each raquo d d was subshyjected to visual dye penetrant x-ray and metallo-graphic ixr^mation and to two tensile and four side-bend tests These tests were conducted in accordance with die ASME Boiler and Pressure Vessel Code Secshytion IX 2 and ail of the above-mentioned welds passed the tests The tensile specimens were machined from the test plates with the weld in the reduced-section gage length and were tested in a Baldwin tensile machine All Hastelloy N welds exceeded the required minimum 100000 psi ultimate tensile strength except the weld of 1 Ti-modified Hastdloy N to type 304 stainless steel which ruptured in the type 304 stainless steel base metal at 93300 psi The side-bend specimens were A X li X approx 8 in long with the weld in the center and were bent around a I-in radius in a guided bend fixture
The chemical analyses of the various materials involved are shown in Table 63 The side-bend specishymens are li in (luck X hi in wide bent around a l-in-radius mandrel in a guided bend test The specimens were macroetched in a solution of HO 20 HNOj -20 H 2 0 to delineate the weld and heat-affected zones Figure 619 u a macrophotograph of side-tnd specimens of standard Hastelloy N heat
N1-5075 Vi-in-thick plate welded with standard Hastelloy N wdd wire heat N I -S I0 I There were no fiows in the specimens after bending and visual dye penMrant x-ray and mrtallographic examination before bending showed that the welds were sound This weld was inde and tested to recertify the welder and to update the welding procedure specification Figure 620 is a reacTophotograph of side-bend specimens of 2 Ti-modified Hastelloy N (top) (heat 74-901) welded to standard Hastelloy N (bottom) (heat N1-5075) with 2 Ti-modified Hastelloy N (heat 75-421) weld wire by welding procedure specification WPS 1402 There were no flaws in the welds and the strain markings delineate the weld areas
Figure 621 is a macrophotograph of 2 Ti-modified Hastelloy N plates (heat 74-901) welded with 2 T i -modilied Hasteiloy N (heat 74-901) weld wire on weldshying procedure specification WPS 1402 There were no flaws in the welds and the specimens were macroetched to delineate the weld areas Figure 622 is a macro-photograph of the same heat of 2 Ti-modified HasteBoy N (74-901) welded with 2 Ti-modified Hastelloy N (heat 75-421) weld wire by specification WPS 1402 There were no flaws in the welds and the specimens Figure 623 is a macrophotograph of side-bend specimens of type 304 stainless steel K-in plate (heat 18024) (top) welded to 2 Ti-modified Hastdshyloy N (heat 74-901) (bottom) with Inco 82T (heat NX 59138-D) weld wire by welding procedure specification WPS 2604 There were no flavs in the welds and the specimens were macroetched to delineate the weld areas
Although special welding procedures were prepared for the joining of standard to 2 Ti-modified Hastelloy N with 2 Ti-modified Hastelloy N filler wire (WPS 1403) and for joining stainless steel to 2 T i - modified Hastdloy N with Inco 82T filler wire (WPS-2606) the parameters used in making these welds were identical to those used in procedures WPS 1402 and WPS-2604 developed for standard Hasteiloy N Thus we believe that the test wdds adequately demonstrate that stanshydard and 2 Ti modified Hastelloy N have equivalent welding characteristics and that procedures WPS 1402 and WPS 2604 can be used for both materials
Supplies of standard Hastelloy N weld wire were depleted over a period r f time and additional wire was purchased to the materials specifications MET-RM-304B However the voidability test was performed by O R N L Plates of standard Hastdloy N (heat 5067) IV t
X 4 X 10 in were welded with the new heat of weld wire from Teledyne Allvac (heat 9725) using welding procedure specification WPS 1402 and were accepted
71
Jiilln l i s i l
1 3
3 laquo m i a m I z
llllpl liillii s a = c e e v
i
i
I I I
Hill s s = s e
Ii2s I
I bull raquo bull
S C O
33 a c e o 3 O m
i
bull mdash copy o r- d 9gt
laquobullraquo bull gt ampgt ltlaquo rraquo laquo r i mdash
1 laquo
z z z
r t a laquo m r- f 2 gtgtilti bull laquor mdash H-
2 2
i ij
72
Ffcfc1 Bead N(heMNI-S075)j Htmuwwtt SIM)
Ffe gtJ0 I M 4 ffcciMtM of 2 T t - m o t f M HmHtoy N (fctrt 7901) art staataaJ H n M o r N (fcMNI-5075) j o M w M i Tt-modiTM Hartdoy N Mkr win (beat 75-421)
73
F laquo J I (heat 74401)
Ffe 622 ttmt (raquotat 75-421)
of J Ti-motfbJ HMcltoy N (beat 74401) f o M wMk 2 Ti-amtttM
74
FlaquoftJ3 i01 tyyc39v 3 I H T H N ( laquo laquo 7441) j IwMUTflkr
as passing all tests including one all-wdd-inetal tensile test and four side-bend tests with no flaws in the welds This material has been made available for general proshyject use
4 STAWLrTY OF VARIOUS MODIFIED HASTEIXOY N ALLOYS IN THE
UNIRRADIATED CONDITION
T K Roche H E McCoy J C Feltner
The stability of Nb- Ti- and Al-containing modified Hastelloy N with respect to intermetallic predpitation known as aging is being studied It is known that addishytions of these elements are desirable respeclivdy for enhancing resistance to tellurium-induced intergranular cracking for improving resistance to radiation embri-tlement and for deoxidizing the alloy during melting However beyond certain levds these dements can cause aging reactions by the predpitation of gamma prime |Nij(AITi)| or NijNb which in turn causes hardening or strengthening and loss of ductility Therefore studies are in progress for defining the amounts of Nb Ti and Al which can be added to Hastdloy N and still maintain a reasonable decree of stability The stabilities of a number of alloys including laboratory semiproduction and production heat having varying amounts of the
demenu in question are being determined by hardness tensile properties creep-rupture properties and micro-structural evaluation
The first approach to evaluating stability has been the determination of the room-temperature hardness of the various alloys before and after heat treatment at 650 704 and 800degC for periods up to 1000 hr The data for alloys held at these temperatures for 100 hr were reshyported previously1 and during the present period the 1000-hr data presented in Table 64 were obtained he data for alloys which show significant hardening relative to the as-annealed condition are Mocked off in the table
The hardness of the various alloys after a 1000-hr aging period follows the same pattern noted for the 100-hr aging period However the previously reported niobium concentrations of the niobium-containing alloys were low due to an analytical error the correct values are shown in Table 64 The present data show that with low aluminum concentrations (00S wt ) niobium contents approaching 2 (rather than as conduded earlier) can be tolerated in 2 Ti-modified
3 T K Roche D N Braski and J C Felfnrr MSK Pro-gum Semmnnu fmgr Rtp Feb 2S 197$ ORNL-5047 pp 71 76
75
lkra llaquoMi7WMri l
DatamMoriui hatdcMBg rcbthc to the
Icoaditiw
IoapoBtun (laquot ) Rockwell
Heat IoapoBtun (laquot )
AaaeaM (
Agt4 1000 were 704c
hr Nb Ti Al C AaaeaM
(
Agt4 1000 were 704c sooc
474-557 214 002 004 SI 5 S7S SSS S74 472-503 194 009 006 S44 S9S 882 891 474-901 IS 010 006 794 857 S63 856 471-114 1- 012 005 792 829 846 S44 427 24 0IS 0014 747 784 773 779 428 247 016 0064 S25 SS2 861 860 474-533 217 04S 005 Sl0 857 S62 849 474-534 209 053 008 893 925 904 909 429 24 0J5 0017 769 9 4 854 74 430 25
2J 034 074
0073 0016
SS6 7S6
1001 88 9 912 431
25 2J
034 074
0073 0016
SS6 7S6 978 984 928
432 048
235 19
069
008
0057 0037
874
SOI
1034 1034 974 425 048
235 19
069
008
0057 0037
874
SOI 841 858 852 421 10 19 007 0048 873 865 878 867 424 134 I S 010 0063 S84 902 SS9 904 418 192
190 20 18
005 015
0058 0055
891 S87
904 900 9IA
904 420
192 190
20 18
005 015
0058 0055
891 S87 1015_
900 9IA 913
435 142 23 015 004 886 1050 1021 903 43S 180 24 013 005 918 1066 1051 968 433 189 2 2 033 0024 848 1043 1021 881 434 186
252 2 bullgt
22 032 015
0061 005
933 931
1070 1088
103 8 1076
957 441
186 252
2 bullgt
22 032 015
0061 005
933 931
1070 1088
103 8 1076 1041
442 30 22 014 0052 950 1093 1096 1072 30 22 014 0052 950
Bavt Ni l2TMo K Cr l h r j | IMTC
Hastdloy N before aging occurs However the tolerance for niobium decreases with small increases in the titashynium and aluminum contents It must be emphasized thai the hardness data were obtained on unstressed specimens and that creep-rupture tests now under way indicate that lower concentrations of niobium are tolershyable when the alloys are subjected to stress These reshysults arc described Uter in this section
The effect of aging on room-temperature and elevzed-tempcralure tensile properties is being detershymined for most of the alloys Limited room-(emperalure results have been obtained after a 100-hr aging period at 650 and 800degC (Table 65) There is good correlation between the tensile data and the preshyviously reported hardness data As would be expected alloys which age harden during a given thermal treatshyment (data underlined in Table 65) also show an inshycrease in strength and a corresponding decreur in ducshytility relative to ihr solution-annealed condition
In the case of the tiunium-aluminum-modified Hastdloy N alloys the hardening phase is most likely gamma prime and this phase has been identified in heat 430 lt 25^ Ti + 034 Al) after 100 hr at 6 5 0 o C
Stress-rupture results for the titaniunvaluminum-modified Hasielloy N alloys at 650 and 704degC are shown in Tables 66 and 67 respectively Again there is very good correlation between age-hardening behavior as determined from short-term hardnlaquo data and the corresponding rupture life in the stress-rupture tests Abo the effect of temperature upon agmg an be seen by comparing the data sets for heats 429 and 430 at 650 and 704degC At the lower temperature both of these alloys hardened but neither hardened at 704degC Since hardening in these alloys is due primarily to the formashytion of gamma prime these results sugges that the gamma prime solvus temperature is located between 650 and 704degC for these two alloys This observation and the other aging data in Tables 6465 and 66 were
76
Tak6-5 raquo i m l all l i l i h t i i i i i i fci iwfNJ-TVAI
iicbtaKtodK
bdquo laquo t t m t ~ - - - StteaajbUO neat _ ^ _ ^ ^ _ _ _ _ _ _ ^ ^ ^ _ _ l o a a m _ ^ _ ^ _ _ _ _ _ Doaaaboa ()
iraquo r At c mum Y j - i ^ ^ 474401 18 010 00 AnwaM Ikr l 7 r c I MO 442 447 794
Aaoil00br50C 114 J $00 559 SIS Aged 100 brS00C I I9JO SI2 537 151
428 247 0 1 00 A a w a M l k t I I 7 T C 124 J 49-0 52 825 Aged 100 br50C 125J $0-5 527 M2 Aftd l0fgtbrS00C 1237 511 411 M7
430 2J 034 007 Aaneakdlbf I177C I2SJ $00 541 St Aac4IWbr5ltrc 1348 634 437 957 Aged 100 brS00C 12 J 531 $00 886
424 134 I a iO 00 AMtafcdlbr I177C 1372 527 512 Ago i00br6$OC 1385 52J 477 (93 Aged 100 brSO0C 1377 547 45S 199
435 142 23 015 004 Aaaeakd 1 hr 1I77C 12S4 510 54 raquo Aged 100 br50C 190 893 353 1025 Aged l00brSOOC 1339 54-5 S3S laquo73
442 30 22 014 003 Aantakd 1 hr II77C 1394 07 $42 Agadl00bf50C 1905 107 251 AftdlOObrSOCTC 144 ~ J 3 J 1 S 9
bull raquo Ni-12 Mo-7 O
TaMe64 St iwiaptmdashe data for wr iow beats of Nb-Tt-AI R M d M H a s t d b ^ N at 6500 aad 474) x I0gt pa
Heat Composition (wt gt Rupture
life (hrgt
Total strain
Are harden Heat
Nb Ti Al C
Rupture life (hrgt
Total strain at 650deg C
474-901 18 010 006 3950 270 No J74-533 217 048 005 4650 280 No 427 24 118 0014 866 217 No 428 247 016 0064 1150deg 73 No 429 24 03laquo 0017 9572 163 Yes 430 25 034 ftO^ 16980 73 Yes 431 2$ 074 0016 23090 101 Yes 432 235 069 0057 41710 21 Yes
42S 048 19 008 0037 14301 237 No 421 104 19 007 0048 20070J 73 No 424 134 18 010 0063 39530 65 No 418 192 20 005 0058 39550 32 No 420 190 18 015 0055 39510 19 Yes 433 189 22 033 0024 41690 10 Yes 434 186 22 032 0061 39550 09 Yes
BaseNi 12 Mo 7Cr Based on turdnest measurements on aged umircutd specimens Tesl still in progress Test discontinued prior to fracture
used to estimate the gamma prime solvus temperature boundaries at 650 and 704degC as a function of aluminum and titanium concentrations Alloys with compositions lying below the proposed boundaries in Fig 624 are stable at the indicated temperature and those above will precipitate gamma prime
With the addition of niobium to titanium-aluminum-modified Hastdloy N defining or predicting stable comshypositions becomes more complex There is evidence1
that mechanical stress significantly affects age hardening of these alloys which is not uncommon The room-temperature hardness data for annealed and aged specishymens of the various Nb-Ti-AI modified Hastdloy N alloys suggest a tolerance of about 2 Nb in a 27 Ti-0-5 Al modified Hastelioy N base (heat 418) beshyfore aging occurs Further increases in the aluminum niobium and titanium contents lead to age hardening at 650degC then at 70degC and finally as high as 8O0degC when the niobium content is increased to about 25 with 22 Ti and 015 Al (heat 441) If the broad assumption is made that the three elements are equally effective in promoting an age-hardening reaction and a plot is made of the total atomic percent of these deshyments (at Nb t Ti + Al) in the various alloys against the increase in hardness (^RBI caused from aging 1000 hr at 650degC a curve is obtained (Fig 625) A sharp break indicative of appreciable aging occurs between 3H and ^M at 1 (Nb + Ti + Al) Adding the variable of stress to aging response and plotting the parameter of minimum creep rate from creep tests at 650degC and 470 X I0 3 psi (Table 68) against total atomic percent (Nb bull Ti + Al) results in the curve shown in Fig 626 The break now is indicated between 2 and J at (Nb + Ti bull Al) The creep rale of alloys containing up to about 2 at rlt (Nb bull Ti + Al) is 15 to 30 X lO^ h t Three heats (70-835 6laquo-648 and 64gt-344) in the 2 to 3 at ^
region which are high in niobiuro and low in titanium are known to age upon creep testing at 650degC at d exhibit creep rates around 1 X 10Jhr One heat (425) with the reverse combination low in niobium and
4 H y McCoy MSK Program Senu4m1L ftogr Rep Feb 29 1972 ORNL-4782 pp 167-69
30
25
7s- i sm
20
z
z o u
15
10
05
NO y
bull704-C -
650 C
02 04 06 Al CUfTENT ()
08 10
F|laquo 624 PlUMJWa bullOMIMJM MSWatl Sttbfc fan bullraquo-staMr alaquoovs of N i - I raquo M o - 7 Cr bull Al and Ti with remcct to p i M prime precipicslioa m S0 and 704degC Alloys above the lines win form ttamma prime and those below wifl not (see Table 64 for the compositions o f the various alloys I
Tab 67 Stress-njptare data for several Urals of litaMM-almiNMM modified Hastetoy N at 704 C and 3SJO X 10 psi
Ileal Compoutiofi twt bull 1
Ti Al
Rupture life (hr)
Total strain
Age hardens at 704C
474-901 474-5 J J 427 428 429 430 431 432
18 217 24 247 24 25 25 235
raquollraquo 1148 IMS 016 035 034 074 069
006 005 0014 0064 0017 0073 0016 0057
1932 I96 0 820
2018 2006 2124
29383 36115
394 420 234 610 227 558
68 137
No No No No No No Yes Ves
Base Ni I Z Mo in Cr
Result ltgtf hardness measurement taken on ated unsirnsrd specimens
78
7S-1JTraquo 20
raquobull
14
an c
i lt
laquo0
bull433
bull 435 U^TA j raquo44l
438 _Llaquolaquo
420
- bull 4 2 5 -
bull 434
mdash~3poundt^~ 4lt8
25 30 42t -bullmdash 35 40 45
at (NbraquoTraquoi) 5 0
Fij 6 J5 Chante M kmimm ol 1 vanon beats of Nb-Ti-AI-amdiTied Haste N after 1000 kr at 650C (see TaMe 64 lor the coMposinons of the bullMiow alori)
TaMe 64 Coayison of hardness changes4 aad creep beharioi of Hasteloy N moOfttd with Nb Ti sad AI
high in titanium does not seem to show much aging Alloys containing 3 to 5 at (Nb bull Ti bull Airaquoage appreshyciably with creep rates of about I X IO3hr or less
The above results indicate that zlloys containing approximately 25 at or less (Nb bull Ti + All will be satisfactory from the aging standpoint Such an alloy would be represented by the composition on a weight percent basis of 05 Nb-I5 Ti-01 AI Alloys having concentrations of Nb + Ti + AI above the 25 at range will be more susceptible to aging
Future work will include evaluation of mkrostructure for a number of these specimens to confirm present conclusions evaluation of additional alloys to test the indicated boundaries for stable compositions and an extension of data analysis to determine whether a quanshytitative relationship can be derived that separates the relative effects of the individual elements Nh Ti and AI on the stability of alloys of this type
65 MECHANICAL OPERTIES OF TOANIUM-MODIFIED HASTELLOY N ALLOYS
IN THE UNIRRADIATED CONDITION
T K Roche J C Feltner B McNabb
Several tests were completed or are in progress to determine the mechanical properties of recently reshyceived heats of 2 Ti modified Hastdloy N in the unirshyradiated condition These alloys include two production heats (74-901 and 75-421) and six semiproduction heats (74-533 74-534 74-535 74-539 74-557 and 74-558)
behavior of several heat
Composition Hardness Kg Minimum creep rate
Cilhx) Heat wl 1 at Annealed 1000 hi
al 650C Change Minimum creep rate
Cilhx) Nb Ti AI C Nb fi + AI
Annealed 1000 hi al 650C Change
237 103 004 lt005 084 15 x 10bull 63 25 lt00I 013 166 il X 10 181 185 050 lt001 0045 186 31 x 10 bull 69448 195 092 005 0043 255 70 x 10 69-344 17 077 024 010 263 26 X 10deg 70-835 26 071 010 0053 282 60 X 10 425 048 19 008 0037 290 801 841 40 78 x 10 421 104 19 007 0O48 324 873 865 -0 8 13 X 10 424 134 18 01 0063 338 886 902 16 71 x 10 418 192 20 005 0058 391 891 904 13 22 x 10 420 190 18 015 0055 387 887 1015 128 1 X 10- 433 189 22 033 0024 475 84 1043 195 2 x 10 434 186 22 032 0061 470 933 1070 137 3 x I 0 -
Alloys aged for 1000 ht at 650degC and hardness measured in unstressed condition Creep tested at 650deg C and 470 x 10 psi f Base Ni 12 Mo 7Cr rflhratll77C
79
6 OANL-OTN 75-Wtf
5 5 k 433 1 raquo434 | 1 1 iHll
- (
I
gt420 M 1
1 tlltk^
- (
I i i
70 -835 lt i T ^ 1 | U 1 bull 69-648 6 - 4 4
I
1 425
2
1
I II 1 i i |
bull S3
M81 2
1
1 1 1 1 i
1 |
bull 237
I 1
10 i - raquo tor4 2 5 laquo r 3 2 s MINIMUM CREEP RATE 1nr)
10 io-
F 626 MiMam cteep rale of vwkms heals of Nb-Ti-AI-nodified Hastelloy N tested at 650degC aatf 47Jgt x 10 pa (s Table 64 for the aloy coiapositicm)
Four of the six semiproduction heats contain small additions of rare earths lanthanum cerium and miscii metal The compositions of these alloys were chosen to study the effectiveness of rare-earth additions for minishymizing the extent of shallow intergranular cracking Each of the six semiproduction alloys was the prodxct of a 120-lb double-melted (vacuum induction plus elec-troslag remeit) heat produced by an outside vendor The chemical analysis of the alloys was reported preshyviously5 The mechanical-property studies include the determination of room- and elevated-temperature tensile properties and creep-rupture properties in air at 650 704 an J 760degC These data serve as a reference for comparison with the properties of standard and other modified Hastelloy N alloys both in the unirradiated and irradiated conditions
The principal effort during this report period was directed toward completing the creep-rupture data on the above heats Tests are being run at three stress levels for each of the three test temperatures Most of the tests were completed with the major exception being heat 75-42 he 8000-lb production heat for which specimens are being prepared Specimens of the other
5 T K Roche 8 McNabb and I C Kcliner MW flj-gnm Stnimnu Progr Rrp Feb 2 1975 ORNL-5047 pp 61 and 65
heats were obtained from swaged rod and were annealed for I hi at 1177degC prior to test
Figures 627 through 629 are plots of rupture time as a function of stress at 650 704 and 760degC respecshytively for the 2 Ti modified Hastelloy N heats and are compared with plots for a previous heat ^471-114) of the same alloy and standard Hastelloy N Minimum creep rates measured from these tests a the three temshyperatures are shown in Fig 630 as a unction of stress As concluded previously the more recent heats of 29t Ti modified Hastelloy N are essentially equivalent in strength to the earlier heat and there is no significant effect resulting from the addition of rare earths to the 2 Ti -modified alloy As determined from past work and confirmed by the recent tests the modified alloy exhibits longer rupture lives than standard Hastelloy N at the three temperatures
Additionally the first of eight creep machines capable of tests in molten fluoride fuel salt was put into operashytion A specimen of heat 474-533 has been in test at 650UC and 300 X 10 3 psi for slightly over 1300 hr Data are not available as yet on this same heat in air but a comparison is made in Table 69 with an air test of an earlier heat (471-114) of the same nominal comshyposition
The data appear to be falling within a normal scatter band for alloys with the same nominal composition that
80
10 2 5 KT RUPTURE TIME (Dr)
Flaquo 6-27 Sueswuptare properties of several heats of 2 Ti-modified Hastcfloy N and standard HasteRoy N at 650 C I Ranges of rupture strain indicated in parentheses)
60
90
= 40
laquogt 30
20
10
0MH-DWC 79-laquoS7raquo0
[ mdashr-1 i j
- laquo gtlaquo 2 Ti-MODIFI bull0 bull AS El -LOT N (HEAT 4 r i - iu raquo i h t
B ( 39
h 4 -
r
II 6261 r ( 3 7
bullIs
I 2-476) -
laquobullraquo bull (
i
bull 174- 33
1
39
h 4 -
r
II 6261 r ( 3 7
bullIs
I 2-476) -
laquobullraquo bull (
368-47
1 6
A 474-535 laquo 474-539 o 474-557
-STANOARS HA STE
I-
LL OY N
o lt raquo74-laquo
1 L
KM
1 1 TES II
T TEMPER
III ITUR
STE
I- 70 4C
11 V 2 10 tOJ 10 RUPTURE TlaquoE (hr)
Fit 62 Strcavmpfare prupeniei of several heats of 2 Ti-modrTwd HacMfojr N aad staadaid HaateBoy N at 704r (Ranees of rupture strains indicated in parentheses)
81
Tvaoraquo 35
30
25
I- -
11 1 1 1 M IMP i | TT bull1 X I i h i j i i
bull -MODIFIED HASTEU0Y N CHEAT 471-14 -1 i IIIH |
i bull i i i
i gt lt
I i h i j i i bull -MODIFIED HASTEU0Y N CHEAT 471-14 -
1 i IIIH | j
j
j | i i
M 1 nH t t Y-
r 1 i n 1
t bull 1 I t I i |
i i i i i V bull i i bull i bull
raquo 474-533 gt 474-534 i 1 M h i t raquo 474-533 gt 474-534 I r bullv M I f f bull 474-535 raquo 474-539 I M i i i 11
o 474-901
1 Mi l l i i T
1
TEST TEMPERATURE
ill I i BOT
i IN to bull 0 2 2 5 SO5
RUPTURE TIME ffcr) bull0
F i j 6 2 9 Strcss-raptate properties of scleral heats of 2 Ti-modified Hasttstoy N and standard lUiMMoj N si 760C- (Ranee of rupture strains indicated in parentheses)
omn-oac n-tsret TV
f 2 5 raquo - MINIMUM CREEP RATE (hr)
Fig 630 Creep properties of scmsl heats of 2 ft-modified HasteHoy N at 650 704 and 760 C Solid lines arc for heat 71-114 and the dashed lines indicate bands which contain the data for the other modified alloys
S2
T M H -Ac mdash l i i r a s w a raquo laquo 1 l
larl 474-533 471-114 iflaufijc farii ltagt
500 13 24 1000 44 1300 35 55
Tlaquowraquo ion ai 650 C n d 300 x 10 pa
are tested under similar conditions and there is no indication that ronoaon by the molten fluoride fuel salt represents a sgmficani factor
jraquo rOSTIRRADUTIONCREEf MtOftRTIES OF MODIFIED HASTELLOY N
HE McCoy TJC Roche
puurade of the ORR Each experiment contains 102 miniature creep specimens in an instrumented facility in whkh temperatures can be measured and controlled by supplying heat from auxiiary heaters Only 12 in-ceU creep uwrtnim are available for postirradianoa creep testing hence the testing proceeds rather slowly The most recent tests have concentrated on lt I ) the propshyerties of six 125-lb senuproduction nests that contain 2 Ti and low concentrations of rare earths and (2gt the properties of several alloys containing both niobium and titanium
The results of tests completed to date on the six heats that contain titanium and rare-earth additions and the (OjOfXKb commercial heat that contains titanium are summarized in Table 610 Previous tests at temperashytures of 6S0 and 704degf showed that the creep propshyerties of these heats are about equivalent The rupture nfe at 650degC and 40JO X I 0 3 psi varied from 1200 to iSCC hr and the rupture life at 704degC and 350 X 10 psi varied from 170 to 200 hr Final conclusions con-
Postirodtion creep tests are in progress on specishymens from five experiments that were irradiated in the
6 T K gnmSemm
Roche i ( l-dlner and B McXabb MSK Pro-mm flop Rep Feb 2 1175 ORNL-5047 p 7
a t 6 S r C a r laquo s a o M n i atUttMecatca
ABojr Ten mantel
Irradiation tcmpcniafle Si ecu
(10 pa) creep rate
(hr)
Rapawe life (hrgt
Total fracture straia Cufaycailioa (gt
474533 R-I9I2 R-190
R-I929
650 650 7ltK 760
400 470 400 350
0025 0050
0035
2311 I I I 5 2
2022
72 217 Ti 04 At 7 6 4 7 J
474-534 R-1913 R-1909
R-1930
650 650 704 760
400 470 400 350
0021 007
0008
5722 660 5raquo 7 3
16 2 209 Ti 0 J 3 Al 001 3 La 69 35 28
474-535 R-I9IS R-I9I I R-1922 R-1926
650 650 704 771
400 470 400 350
0016 0099 0023 0019
7 6 M 930
4677 6454
1V6 2 1 3 Ti 055 Al 004 rare car TS
123 139
474-539 R-I9I4 R-I9I0 R-I92I R-1925
650 laquoS0 713 774
40 JO 470 400 350
0020 011 0C3I 0000
601 739
4295 12200
108 193 Ti 020 Al 003 Ce 97
165 114
474-557 R-1920 R-1923 R-1927
671 713 771
470 400 350
0045 0044 0019
2174 162 434S
1 0 214 Ti 002 Al 95 S3
474-55 R-I9I6 R-1924 R-192
650 716 795
470 400 350
0X192 0021 0012
1793 475
79 205 Ti 0-02 Al 002 U 6 II
474-901 R-1936 R-1937 R-1907
650 70laquo 732
470 470 470
0069 015 014
1716 332 525
1 3 10Ti00Al 52 1A
AD specimens lancaM I hr agt 1177C prior (o irradiation for M 100 hr to a thermal thence of vlt3 x 1 0 neutronscm Alloy nominal bast composition of Ni 12 Mo 7 Cr -005 C
S3
cerning the postinadiation properties (Tabk 610) are not possible because the tot matrix ha not been comshypleted Specimens irradiated at 650degC and tested at 650degC hare rupture lives that are about half those of the unirradiated specimens but there are no differences in the properties of the various heats that are considered significant in view of the limited data The properties of afl heats are considered good after irradiation at 650C After irradiation at 704degC and testing at 650degC and 400 X 10 pa the rupture lives of heats 474-533 and 474-534 appear to be lower than those for the other heats by a factor of 3 In afl cases the rupture life and the fracture strain were lower after irradiation at 704degC than at 650degC After irradiation at V760C and testing at 350 X I 0 3 psi at 650C the rupture fafe varied from 43 to 1220 hr and the fracture strain from II to 114
respectively Thus differences in creep behavior of th-se aftoys likely become progressively more important as the irradiation temperature is increased
The fracture strains of the various heats appear to show significant trends with increasing irradiation temshyperature Heats 474-533 and 474-557 have good fracshyture strains (6 to 104) which do not decrease apprecishyably with increasing irradiation temperature The fracshyture strains of heats 474-535 and 474-539 are i t the range of 10 to 16 and do not change appreciably with irradiation temperature Alloys 474-534 and 474-558 show decreasing fracture strains with increasing irradiashytion temperature The behavior of alloy 474401 appears to be unique in that it shows a marked drop in fracture strain as the irradiation temperature is inshycreased from 650 to 704C However this effect may
Ta t 611 bullMtffiall rNamwsaKsrc
Alloy Test HftlhCT
Sims HO psi)
creep rale
Rapt me ate lthrgt
Total fraclarc sin in
rfhraquogt
Rapt me ate lthrgt ltgt
428 R-1948 470 0043 2221 119 474-533 R-1908 470 0050 I I I S 78
R- I9I2 400 0025 2311 72 430 R-1947 470 lt00049 9720 4 8 r
432 R-1946 470 lt00005l 9720 0SC
431 It-1945 470 bullCO0024 972f 424 R- I9 I9 350 Mraquo 3160
400 000024 1406 470 000033 4526 550 00066 9494 78
424 R-1944 630 00096 3554 104 420 R-I9I8 350 bullM) 5322
400 -v-0 1405 470 000021 4509 550 000037 6959 630 000080 3343 700 00062 2776 4 3
420 R-1943 630 lt000l7 10680 18 418 R 1917 350 000002 6514
400 000007 1406 470 000014 4523 550 00040 7948 54
41ft R-1942 630 00022 5592 72 434 630 lt0085 129 II 433 R-1949 630 lt0 00 l l 6600 075
AN specimens annealed I hr al I I77degr prior to irradiation Irradiation carried out al 650C for approximately 1100 hr to a thermal flaencc of Vraquo x 1 0 neutronscm See Table 64 for detailed chemical analyses Test still in progress Stress increased on the same specimen in the increments shown
S4
tt12 laquo T SIMMS CM
AcebaMk maibS0CbjMlaquotoi rtniliij1i4
CoMBoanmi iwt rt Co H o
lOOObraMeal
ctccp cveep behavior
bull S O T f o r V I I W b f 4
CoMBoanmi iwt rt Co mdashjn bullnn a m t H o
lOOObraMeal
ctccp cveep behavior
bull S O T f o r V I I W b f 4
Nb T i Al Nb bull Ti bull Al
428 No No No 247 Olfc 357 474-533 No No No 217 laquo4t 3 raquo 2 430 Yes Yes Yes 2J 0 J 4 492 432 Yes Yes Yes 235 0Alaquoraquo 4 A 3 431 Yes Yes Yes 25 074 4 9 424 No Yes Yes I J 4 I S 010 33 420 Yes Yes Yes 10 I S 015 3S7 4 I t No Yes Yes l laquo 20 005 3 1 434 Yes Yes Yes iaraquo 22 032 470 433 Yes Yes Yes l laquo 22 033 475
Sec Tabfc 1 4 for c l e t M e U t f e M U analyses
F I O M Table 4 rFroaraquo Table t A based ltM ctmatemiomt of data i ON novate Me aMl total u n a rfFrow Table 611
be related to the strain rate a summary these sparse data sanest that the fracture strains of alloys cow-taming only titanium and those containing titanium plus cerium remain at adequate levels as the irradiation temperature n increased while the fracture strains of the two alloys (474-534 and 474-558) that contain lanshythanum do not Additional specimens were irradiated and tested to check tins important poatt
Section 64 of this report deals in detail with the metaOurgical stability of alloys containing Nb Ti and Al in the unirradiated condition Some of these alloys have been irradiated and limited test results are availshyable (Table 6) The alloys were annealed for I hr at 11770 prior to irradiation for about 1100 hr at 650C The anneal at 1177degC should have dissolved most of the alloying dements and the subsequent period at 650degC may have resulted in the formation of gamma prime Precipitation of this embrittling phase abo strengthens an aBoy hence the postirradution creep tests should show whether significant quantities of gamma prime were formed As dacussed in Sect 6 4 precipitation of bullhis phase may be strain induced and a detailed analysis of the creep data wSI be required to determine whether the gamma prime formed m the specimens during irradishyation or whether it fonrvf as the spedmens were stressed initially
The data from Table 611 and information from Sect 64 are summarized in Table 612 which shows that the
conclusions are reached with regard to aging of creep specimen in the unirradiated and irradiated con-drtions However hardness measurements on unstressed umrradaied specimens fail to be a good indication of agt in aRoys containing nioHum Alloys having a com-tlaquoKd titanium and aluminum content as high as 357 at had excearnt postirradution properties ABuys with higher uimbimd concentrations are quite strong Kut no conclusion can be made about their fracture stains All of the alloys containing Nb Ti and Al are quite strong and can lake considerable strain before fracturing ABoy 434 has a low fracture strain waste no conclusion can be drawn relative to ahoy 433
The alloys containing Nb Tiand Al which have been evaluated thus far are likely too highly alloyed even though some of the fracture strains jre acceptable Less highly alloyed materials are being irradiated
67 MlCKOSTRUCTURAL ANALYSIS OF T i T A N M M I O W I E D HASTELLOY N
D N Braski J M LeMnaUr G A Potter
The first part of this section presents the results of microstruclural studies of two titanium-modified Hastefloy N aloys 472-503 (designated 503) and 471 -114 (designated as 114) Previous analyses of these tame two alloys dealt with their nricrostructwss after
bulls
afmf aad after postsrraanrtion creep tests In the pressai m f j i l f the nacroairaciaret ot hutfcaftoys were analyzed M an attempt 10 explain some w u l pouarsdanoa creep teattts M sptoaaas that were pven a ltjfgtrtj higher soratiua aaaeahnf treatment Move trratmttian I V mdym showed that many at the wlaquo ipninsrai owe t f i e mhumimracnni and that tkc poor creep properties ttiaMmsonsr cases tie related lo the iahomimnKitsti D M ftnamg prompted a sindy aanei at iiiiidwiag asm hinaimiatimi llamllin N aloys The problem if betw approached by rcdactae it carbon coateat of the anoy aad by gnaw carefal attention ID the tahjicatani pmmHcn The resales ot taaml narranrnti to tnWicalt hiaanpariita alloys arc pKsvnacd m BM secoad part o( thjis section
471 M f u m i r i a i J M r laquo f JkaaysSISamllH
rVanmnaaaaa O H I I o n The retails of creep ten o specimen of ahoys 503 aad 114 which had keen PKVSUmdash)y irradiated in the ORR al 7a0C Me given in I hgt 6 J I The creep tots wete contacted at 6501 n a turn and of 350 X I 0 3 pa This partwalar scots laquoraquof spnameas was designed lo show mc effect of tobmoa anatjbni remperatarc on the postkravniion aeep rop-r-re We of the naieriah The solation anneal was a I-hi heal ireainieM and was given lo all sprcimens before ikes were irradiated 4 men in Fig 6 J I ibe 503 speci-men given the standard I br at 117 ( solation anneal demonstrated food creep iiipiwic We wbifc the 114 tprvmen given the amc ircaimenl had a comparably short lifetime However with an mcrease of only ^30degC in aim latins temperature ahoy 503 had a freatty reduced lifetime wMe ahoy 114 thawed marked improvement It wn corasdered ankkety that tkese rendu coaM he canted by changes in solution anncaing tcmpcrainre alone and other posabh cxpla-aatioas were soajbl It b important to note that despite the apparent mtfaMiiy in creep behavior the properties of the 2 Ti modified alloys arc gencraiy food The problem is that lo determine why tome specimens have poor properties A bullohtlhm to this problem was sonjht by carrTafly anatyimf the microttrnctnres of the two alloy 503 and 114 tpecrmens described above
7 D N bullgt I M UMmfccr jml f i A Puller JfSff AOBVM Semtmmm ffngr Hep Am J I 174 OHm-5011 pp 2 M
n I) S Hrai I M Inraoker j J ti A fnwr 10ft rtomm Semtmmu hop Htp Frh 197 ORNI -5047 Pf i vn
am-a t-laquotlt H 0 O ^
snvss ifwfi bull raquooooraquot
llaquo00 i bull ~ i
bullooraquo 7 1
SOI I
1 z- 2 aosf tr
w r T~iHr-wV---
eoo^mdash mdash mdash - 7 - l V mdash ^
laquoooo tlaquooo laquotoo laquoJOC tOkwtio mntauvs rtanjntTtM ltKgt
Hattys SWanf IM at wfTC ahw Irmthmm toOU wr laanm
TtasmnJtvJmi eltclnm nncrattwny Samples were preshypared for iransnaanoa ekciron nacroscopv iT lMi bgt elevtropohaaaf small transverse sections a( the tested creep specimens in perchloric acid sohrtions Frfures tgt32 and 6J3 show electron naaofrapbs repteseniattvc laquogtf 503 and 114 specimens respectively Hfare tgt32 shows an area near a frain boandargt in the 503 specishymen annealed at I I 7 7 C The nacroHnictaie was obshyserved to contain NT-type jwkaiii both in the ftsin bnandiry aad m the form of tmaH ptattieis DMoca-lions were nearly always foond to be aawoMcd raquotih ike MC plasestis The 50specimen anaeaWd at iagtraquoC had ssaabw featarn laquoFsg 6-321 In both speenneas ibe MC pbielets were coaccntrated near the grain boundshyaries This tajfrsts that the element or elements (probshyably titanhan) awimf ap the MC-type carbide in both specimens wete not anifonaty dittrrbwted ihroafhoat the ntntrix Rfare 6JJ shows ehxtron araquoao|raphs of ike 114 specimens aaaeated at II77C(Fig6J3tand I204f (Fhgt 6J3raquo These specinwas also contained tine hJCMype cjrbidei bat aalwd of formmf pbtekts they precipitated oat on stscUnf faalu The suckmf fault precipitates initiate from iaiocstioat aanriaUd with preexitlmi or primary MC carbides and frow atom ( l l l l pbmrs The primary bX carbides (the dark
9 J si raquotVudt j4 raquo ) IWHUM PariHl Praquogt^i-raquolaquo
FfctJL iirrcraquogt
IMi to to ON m C alaquo r c w i laf I fct laf ItonlSMT
FfcUX 11 rrr laquoraquoMMMI~
bullraquo laquobull IH aft i 4rflt ifctMijarr
bull7
bullJS maunutj I t 93 n r r r IFBJ 6jlaquoaraquo a hai laquobull
face ocal oadu laquo laquowieau of
I M laquo F v J 4 laquo ^
f i W t laquomajm awir loaae Iraquoraquo bull ulaquoaagt aavm tar rmttte mctmm of tar Maaak TW laquoaraquo-hlaquoir i i i i f m mt omtfutd raquoH w w n n MC-fraquoar pat-iarraquo atad ar m bar pml r i nraquo the | bullveil) at fafencaiMa)- Suit aifcaiettfaiamare i loth atatuicw M Fa 6J6 bgt the iafJMf t laquo mdashlaquopmm ukra gt4 oW 503 aajdaara 1W 503 laquofrltMMraquo J M K J M j i I5M C hai oaka iem tracks Ifiy 634raquo| feat laquoa a lacat arja aaaarealh Me to
ka4 a sfcvrt crer raatare life aha M a ^bullXM2laquo4hKk m l Mi fit my (filaquo J5 IL K M -
bullera m mm Sm mtomm (Fftj J4raquo|i h mm akv I thai aartee aacks bull jraiar fiw layer TW 114
I2MdegClaquoFlaquoJ$raquo)lt
the tenet 509 aaaatn (Fig 3Saraquo Hat layer tana) a e 53 mm 114 air-aafi
aa ie i t jn at II77C ai anjon
baen of i l aaa ltA0J raquo ) a w u t e m I at aacoad 617 after OlaquoCP tern at I W f C raquooraquo i r at bullraquo M a a OI I I I i n 500 pmm oBjaea- T V bet of cartwtci ai tar tarface lever any teae at tarn
in I U a laquoN1 i fcc ~ IW f f v i olt bull m bullbullbull ngt bull mp ttaatmdash ftuauwt l laquo a i i rlaquoWKftll~l raquofJaar 1731
617 M
+rnm
OTraquomm
ttm mOtOimTttrc am IMtMTC
growth m the 503 specimen (Fig 6 35| during the soMMwa mmtd h is Midear as to
certain tptcimrai haw the carbide-free layers 1 specimens were svoposedry fabricated in the
same way The malts of the mrtafcajraphtc and TBI lt
lion cannot be nsed to fnty explain the i which led to the early creep fnlnrc of two of the specishymens studied However we banc shown that a awnber of aticrostractaral inhoniofmirties exist in the 25t Ti asotified rLarloy N aftoys induding carbide-foe sur-face layer tnrft-grsia lint snrface hyers nmeratwd carbide strinnprs and nononifonn diHribniions of Mf-type carbide nor grain boundaries Some of these
ties appeared to affect the resnhs of tots and may also inflnence other hnpor-
snch as those renting to tclarium attack Consequently a stndy was initialed to prodace rtsstd-loy N aftoys with more homogenous nacrostradares
bull J J llinnnmiim UnmfJy H Aiayraquo
The problem of prodacing Hastdoy N alloys with hiuaugtmuui nacrostructures is being approached in two ways The first is to reduce the carbon content in the atoy to ensure that aR of the MC-type carbides are diaailvud daring the solution annealing treatment If all
the carbides could be held in solution daring fabricashytion the formation of carbide a ringers might be eKna-aated The second approach b a detailed evaluation of tbt fabrication process This latter effort is prwmily
at identifying the steps at which the different ae introduced and finding suitable
akemate processing methods to remove the anno-anajftiti A definite concern throughout the entire study is that any successful fabrication changes also be
immmiil practices The first series of experiments was
to cmnJnate carbide stringers by reducing the carbon content of the ahoy Thermodynamic takula-tions aung data from previous experiments indicated that aN of the carbides should dnsorve at I I77degC in aloys with carbon contents of less than OA45 wt 7 Therefore two aloys 451 and 453 both wtth a nomishynal lauteaoy N convocation (13 wt Mo 7 gtt Ct bal Ni) and 144 wl Ti were cast into l-m-omm marts having carbon contents of 0017 and 0035 wt 7 respectively The fabrication schedule called for the cast ingots to be hot swaged at I I77degC from a I-in to a 0430-in diameter and then to be annealed at I I77degC for I hr The rods were farther reduced o a 0 J37-in diameter by cold swaging annealed at I I77degC for I hr and cold swaged to raquo final diameter of 0250 in One-inch-long samples were then cut from each alloy rod
bull 9
encapsulated in quart urJer an argon atmosphere and aged at 7G0degC for 16-5 hr to precipitate the carbides After aging the carbides in alloy 453 (0035 C| were extracted clectrochermcally in a methanol 107 HC1 solution Consecutive extractions produced the profile shown in Fig 6 J 7 of wt 7 carbide precrpiuie through the thickness of the sample The profile for alloy 453 is considerably more uniform than those obserad for alloys 503 and 114 specimens aged at 750degC for 1000 hr The difference may not be entirely due to a reducshytion in carbon content because the 503 and 114specishymens were swaged from bars cut from i-in-thick plate not from drop-cast ingots (Carbides are fairly unishyformly distributed in the grain boundaries of the 2-lb laboratory ingots while they appear as stringers in the A-in plate) Meiallographic examination of the aged 451 and 453 samples (Fig 6 J 8 ) showed that the reducshy
tion in carbon content did not ehrninafe the carbide stringers However the stringers were liner and more evenly distributed than those observed previously (Fig 6J4o) Carbide-free surface layers were observed in both specimens a typical surface layer in a heavily etched 453 sample is shown in Fig 6 J 9 The depth of the carbide-free surface layer was V0U03 m
Fatifcpnwn One of the moat critical steps in fabrishycating tbtf^iioy N aRoys with respect to its effect on microstruciurr laquo the solution anneal Electrochemical extractions on an as-swaged alloy 453 (00353 Cgtsamshyple showed that a moderate number of carbide panicles (M) 2T) was present Hi the microstructure after procshyessing It a suspected that the sample was not adeshyquately annealed at 1177degC prior to the final cold swagshying operation That is the annealing lime was too short or the annealing temperature was actually less than
90
0080 O0TS FMQHOWTEtOF
X amy Mkif S03 JI 1177 f M lt jpee gti laquocopylt for
I ITTC Therefore the respuMe of tiUmum-mudifWd thneloy to sohnion aaandias at I I77degt ws stmfced as a fmctioa of time at temperature
Samples of aloy 451 |OJOI7 Craquo W anon at I IT7degC for 15 mm lo hr The cleaned etectrucheaacaRy for 6 hr to remove any nr-faoe effects ami the carbides were electrochemical extracted separated ami weighed The resatts of this experanent aw plotted m Rg 640 (My extremely
bullis of prcopitaies were present a samples for 2 hi or more At times less than 2 hr there
scalier m the data hat m geaerai chfHIv preopifc te was extracted These remits indicate
that JO to 60 mm are weeded m addition to the stanshydard 14 sohtiox anneal at 11 T T r to dtooKv the carshybides completely Muumaptu of tectioas from each of the samples r f aloy 451 from the first jaarmaj series are mown irgt Fig 641 Little gram growth was omened between the 154am and 14v anneals while mgbt grain growth was etideai after 2 hr at II77degC As expected rather extensive growth occurred at the longer j times of 4 and 8 hr
FfcnJB Wcwsmnmwof limn wimfml llsmliy N amyi451 jM7Cgt anl 4raquo IftWW O after coal maawwanl aanf at TMTCfbr I US fcr (laquogt Alloy 451 laquoAgt AHny 45 J
91
foert seed-
Abhoaeb most of ike effort m ties stedy hat beea pit wii be exammed mdashtuiognfkicjh before deeded towvd etmeeetioa of canede miegrn a the aflaquoer a soaatioa aaeri at 1177C I b j bull a bullloys enprrimdashrii aieafao mdashdet way to i i i f i i a n the iimiag eomt a t e mdash taebidr few b y m cjHeoftie carbide-free layersm oar experiment Bee- alnae ibr mdenrd irrliw nf
a w that n any effects of bet or cob) Y-133201 mmraquobemremoeedby
there is ike coaaderata eery bull fact be the bey to uioootaH a ahoy A aoajher of rchmvesy eeeor cheaats bull the way ibe eeecviel is leeeeed amy mwe oaaaaptK effects oa
4SI awi 453 aie ui l i l l aai wal be tnMcated to CiVideraquofiw]|Bmemmmmmmmmmmmmmml 025ampmemai rod with special attewtioa peel to the
CSl nOwal t h e W O f k HBOC l lHOWHKNVt the B I O O 0 B H K SO
J SALT COMtOOON STOKES
J R J R Difdkno E J Lawrence
by of
FbgtraquoJ9 i t u n a
453
The conoaoa of bow) asefcei-mniten ihtonac salts has ben the research for aemy years Resell seen as FeFj NiF and HF in the sah react with con-sliteeats of the alloys bet corrosion from these soartes a basiled by the seppiy of reactaets The strongest oxidant of the normal coaetiteeats of foH salt is UF 4 and of the major coastrteeets of most iron- am nkfcei-base alloys cbrommm forms the most stable fleoride Coaeeoeeetly the major corroajon reaction between
02 OftftJL-OWG 7 5 - 1 2 2 4 )
5
imdashimdashimdashr o 1st ANNEALING RUN laquobull 2nd ANNEALING RUN o 3rd ANNEALING RUN bull 4th ANNEALING RUN
2 3 4 5 TIME AT 1177 C (hr)
FfeSvMl AmcmMoliBAim$9tncmihomraquonor4Slmraquotmgtctomlt4Vmmmitioraquo
8
bullfii7rc
92
to) CM ltlaquogt
FltMI MkioaMjai of mdash bull I br kit 2 br laquoraquobullraquo 4 br jfld if) nr
i laquorf raquo r 451 aftw M M M Mlirrcfcw tol IS i ltraquogtMl ltrgt
nickel- or iron-base alloys and molten-salt reactor fuel salt has been found to be
2UF 4(dgtCrfc)^2UF(draquoCrFj(dgt
Because the equilibrium constant for this reaction has a small temperature dependence temperature gradient mass transfer can occur and results in continuous reshymoval of chromium from the hotter sections of a system and a continuous deposition of chromium in the cooler sections
The experiments described in this section are being conducted to determine the corrosion rate of various
sall-afloy systems under controBed test conditions The variables include compoatiou of the alloy oxidation potential of the salt temperature and exposure time Afl loops incorporate electrochemical probes to measure the concent ration of uranium and transilion-metal flushyorides The systems used to conduct these experiments include one forced circulation loop operated by personshynel in the Reactor Division and three thermal convecshytion loops Five additional thermal convection loops have been constructed and are being prepared foi effrj-tion The status of these eight thermal convection loops is summarized in Table 613
93
i l l l f lS
IA
raquo
raquo
tit
MRSkr
l l t e M JS
rN
it
h i
M l
laquo J I Fael M l
Two thermal convection loop NCL 2 IA and NCL 23 have been operating with M S W fuel salt iLiF-BeFj -T lr f^- lF M M 1 7 - O J mote ^raquo lo obtain baseline common data NCL 21A is a HasieOoy N loop with specimen of the same material At with a l thet-mal convection loops dghi specimens are inserted in the hot and the coid legs The 16 spedmens are reshymoved periodicaly for visual examination and weighing The results of the weight change measurements are shown in Fig 642 The corrosion rate of the hottest specimen in this loop is somewhat higher than has been observed in other rfasteUoy N systems (see Sect 682 discussion of FCL-2bgt The higher corrosion rale of loop 21A relaies to the relatively high oxidation potenshytial o( the salt in this loop ( U M about 10 I Horn-evei assuming uniform removal of material the corshyrosion rate of the hottest specimen was 024 milyear which is within acceptable limiis This loop will conshytinue to be used lo obtain corrosion data for Hastelloy N in kali with a relatively high oxidation potential
Loop NCL 23 is constructed of fnconet 601 and has specimens of the same material A loop was built of tnconel 601 because of this afieys resistance to grain boundary penetration by lefuriwn Since the alloy conshytains ZV Cr there was concern about its ability to resist attack by molten fluoride salt The corrosion rate of Inconel 601 in fuel salt was determined from weight measurements of the 16 spedmens of loop 23 and the results are shown m Fig 6 4 3 All specimens lost weight and the lost shown by the hottest spedmen w very large The material lost by the hottest spedmens did not result in uniform removal of the surface but resulted in the formation of the porous surface strucshyture shown in Fig 644 As shown in Fig 645 electron microprobe examination of this spedmen showed high thorium concentration in the pores The only known source of thorium was the salt which contained T h F 4 so it is very likely that the salt penetrated the pores Continuous line scans with the microprobe indicated a depletion of chromium near the surface Figure 646 shows the results of analysis for Ni Cr jnd Th This figure clearly shows the chromium concentration gra-
94
OMK-WH TO-IZZ4 1 1 1
0 laquo000 2000 JJ00 4O00 5000 SPECIMEN EXPOSURE TINE ltgt
Flaquo 642 Welaquoht campMfts of HasteBoy N p-ciaraquoeas fro loop NCL-2IA exposed raquo MSMt fad o k at the indicated tenMcnaMe
0OM-0VC T raquo - t laquo laquo 5
SPECIMEN EXPOSURE TIME (Hrl
F 643 Weht changes of Inconei 601 specimens from loop NCL-23 exposed to MSBR fad salt at the indicated tem-peratare
dient and provides further evidence of the presence of thorium in the pores Deposits such as those shown in Fig 647 formed on the specimens in the cold leg and the deposits were identified by microprobe analysis as chromium This compatibility test of Inconei 601 in MSBR fuel salt shows a relatively high corrosion rate and it is doubtful that this alloy would be suitable for use in an MSBR under the conditions of this test
The lower limit for the U ^ U ^ ratio in an MSBR will likely be determined by the conditions under which the reaction
4 U F + 2 C i r 3 U F 4 U C 2
proceeds to the right Because the salt in loop NCL 23 is strongly reducing with a U ^ U ratio of less than 6 it was decided to try to reproduce the results of Toth and
Gilpatrick1 wiuch predicted that at temperatures below 550degC and VV ratios below 6 the U t would be stable However graphite specimens exposed to the salt for 500 hr did not show any evidence of U C 2 The specimens used were made of pyrolytic graphshyite and it is likely that the high density of the material limited contact of the salt and graphite The experiment is being repeated with a less dense graphite
682 Fad Salt Forced Gmriatioa Loop
Hastelloy N forced circulation loop FCL-2b has been operated during this reporting period to gather baseline corrosion data under conditions where the i r U ratio was relatively low (see Sect 23) Eighteen itastel-loy N specimens were exposed to MSBR fuel salt with a U 7 U V ratio of aUut 100 The specimens were reshymoved at predetermined intervals for visual examination and weighing and the weight changes are shown in Fig 648 Six specimens were held at each of three temperashytures 704 635 and 566 eC Of the six specimens at each temperature three were exposed to salt having a velocity of 049 msec and three to salt having a veshylocity of 024 msec No -ffect of salt velocity on the corrosion rate was found so each data point represents the average weight loss of the six specimens The weight loss of the specimens at the highest temperature correshysponds to a uniform corrosion rate of 011 milyear Uniform corrosion at this rate is acceptable and well within the limits which can be tolerated in an MSBR
Following termination of the ^3200-hr corrosion experiment FCL-2b was to be used to make heat transshyfer measurements This operation has been delayed because a salt leak developed and a section of the W-in-diam Hastelloy N tubing had to be replaced (see Sect 23) Examination of the tubing in the vicinity of the leak is under way
Further corrosion measurements will be made in this loop with the U7U ratio at about 10 Additions of N i F 2 traquo the salt will be made to raise the U ^ U 3 ratio to the desired level
683 Coolant Salt Thermal Convection Loops
Thermal convection loop NCL 31 is constructed of type 316 stainless steel and contains LiF-BeF2 (66-34 mole ) coolant salt The 16 removable corrosion specishymens are also nude of type 316 stainless steel The maximum temperature of the loop is 639degC and the minimum temperature is 482degC The initial objective of
I I L M Toth and L O Gilpatrick The Equilibrium of Dilute UP Solutions Contained in (imphite ORNL-TM-4056 (December 1972)
95
_o o
tvri O
o O
-o d
FtJ 644 Microfracture of Incoad 601 exposed lo MSBR fad sah al 704 C for 720 hr As polished
Y-1312W
BackscoMered Electrons ThMc X-Roys
Ffc 645 Electron beam scanning image of Incond 601 exposed lo MSBR luH tall for 720 br al 7 0 4 C
HImdash3000 COUNTS FUU SCALE Ctmdash3000 COUNTS FUU SCALE THmdash000 COUNTS FUU SCALE
~~1
Y - 1 3 1 2 1 9
I L i JLJJJ - mi
Ffe 646 Mfcfopnbe ctmtimomi K M K M M M corroded ana in IMCOMI 601 exposed io MSMt M salt for 720 hr at 704deg C
97
Fij 647 Microstnctare of lacoael 601 exposed to MSraquoR fad alt at S66degC for 720 kr As pofohed
cobalt-base alloys is being evaluated in the unstressed condition in the TV A Bull Run Steam Rant Two heats of standard Hastelloy N tubing (N1S09S and N1SI01) are being evaluated in the stressed condition from 280 X 10 to 770 X IO Jpsi
The method whereby the specimens are stressed is shown in Fig 649 The wall thickness of the gage secshytion of the specimens was varied from 0D10 in (77X) X 10 psi) to 0030 in (280 X 10 1 psi) to produce the desired stress range The raquo-in-OD capillary tube conshynects the annulus between the two tubes to the conshydenser When the inner tube ruptures steam passes through the capillary and a rise in temperature of a thermocouple attached to the capillary indicates rupshyture Time to rupture can be taken directly from the multipoint recorder and plotted vs sfess for design purshyposes Data of this type for periods as long as 11000 hr were reported previously17
A photograph of the specimen holder (Fig -gt0) shows the ten instrumented stressed specimens the four uninstrumented stressed specimens in the filter basket and the unstressed sheet specimens bolted to the speci-
12 B McNabb and H E McCoy MSR Program Semiarmu Progr Rep Feb 28 1975 ORNI 5047 pp 94-101
OJKM-0W4 TS-lt22laquolaquo
O 500 IO00 ISOO 2000 2500 3000 3500 SPCCIMEN EXPOSURE TIME (hr)
Ffc 648 wetgtt changes of HMCHOY N from loop FCL-2b exposed to MSBR fact salt at die Minted temperatare
this loop is to provide baseline corrosion data on a comshymercial iron-base alloy The loop has been in operation for 248 hr
69 CORROSION OF HASTELLOY N AND OTHER ALLOYS IN STEAM
B McNabb HE McCoy
The corrosion resistance of several heats of standard and modified Hastelloy N and other iron- nickel- and
98
OB -OK M - 3
STEM SUPPLY 99ooplaquomgtr
t laquo - IT raquolaquobulllaquo
C t f U M V f TUBE
TUBE BURST SPECIMEN (TYP 10) WATER OUT
RETURN TO CONDENSATE STORAGE
f 649 ScfccaMtk of dostfe-watcd tobe-barst eciam
men holder The filter basket bolts to the small flanges on each side of the sheet specimens (shown exposed) so that the specimens are covered and the flow of steam is uirected over the specimens rather than around them The steam enters the specimen chamber near the middle of the stressed specimens in front of the unstressed specimen holder and is directed lengthwise over the two stacks of 2-in-long X H-in-wide X 0035-in-thick sheet specimens The steam passing over the specimens flows through the Neva-Clog filter to prevent scale from entershying the flow restricter orifice or the remainder of the steam system The steam is condensed and relumed to the condensate storage vessel No specimen has lost any scale so far but some of the Croloy-type alloys are beginning to develop blisters a prelude to scaling The oxide on all HasteUoy N specimens is thin and adshyherent with no evidence of scaling Some of the unshystressed Hasteiloy N specimens have been exposed to steam for 19000 hr at 538degC and 3500 psig Several alloys were included in this study andas reported preshyviously 3 they displayed a wide range of oxidation rates Several obeyed the parabolic rate law Aw = Kt0gt where Aw is the weight change in mgcm 2 r is the time in hours and AT is a constant Figure 6SI is a
log-log plot of weigh change in mgcm as a function of time in hours Note the sudden increase hi the rate of weight change with each alloy gaining approximately 05 mgcm z over the last 4000 hr This probably indishycates deposition of some substance on the specimens at a rate that was equal for all specimens We noted preshyviously that fine particles of iron oxide that was enshytrained in the steam had deposited on the specimens but this deposition occurred at a much lower and conshystant rale
The increased rale of weight gain for bulllaquo specimens was discussed with Bull Run engineers The Butt Run facility has had several instances of condenser tube leaks in the last year of operation whereas in previous years few if any condenser leaks occurred The cooling water in the condensers is at higher pressure than the condensshying steam to prevent back pressure on the turbines and when a leak occurs untreated cooling water is introshyduced into the steam system hot wed Continuous monitoring of silicon in the four hot wells (condensed
13 H K McCoy and B McNabb Common of Seven fron-md SirkelBttr AUoyj in SMptnrihctl Steam tt IWmfF ORNL-TM-4552(AupB( 19741
99
yen ttSO fhnnnif of MM M H mwooaw dumber attar I9JBM hr of ixpamdashJI Fntaro to note ire the ftrcacd D M mcmlnMnmicd iptcimem m ihr fitter Iforeiivimdl the two grown laquo f umtreued ipecanens and the tea nwuaacMcd tfrcued iptnanm The Miem-rf ltrcanem haw an oniadc domclcr at I in and a length of 3 in
steam wdfc) indicates a condenser leak when the silicon lewd increases and the leaking condenser can be isoshylated and repaired The condensed steam (and any coolshying water mtrodticed by condenser leakage) poses through demineahzrrs and is ntonitored again with silishycon and other irapuifies being held below acceptable broils before the condensate is returned to the steam system Even though care is taken to prevent excessive amounts of imonritres in the steam system the farihiy is evidently opt rating with a different level of impurities than had been experienced before condenser problems developed Some evidence of indium shkate as a Mack-Mi gray deponihas been observed on some safety-valve seats and this is poanoty the material that has deposited on the specimens The oxide on most of the specimens is Mack or gray and no changes in i u appearance were noticed during routine examination and weighing of the
specimens When the specimen holder is removed for the next scheduled examination an effort w i l be made to determine the composition and nature of the deposit
by Bofl Run engineers in the near future to ehrninate the problem of condenser leaks
Some of the aloys represented in Fig 651 lost weight inriiany before gaming at an accefcaraied rate during the last 4000 hr These alloys were Hastetoy X ttsynes alloy 188 and rnconel 718 and they contain approximately 205 Cr Other juvestigstors have reshyported weight losses due to loss of chromium in steam at high temperatures I i is probable that these aHoys would have continued to lose weight if the steam conshyditions had not changed new specimens of some of the aloys WW be inserted in the lest facility when sieam conditions improve
MS
t I t OBSERVATIONS OF REACTIONS IN METAL-TELLURIUM-SALT SYSTEMS
J Brynestad
Several criteria must be met for a good screening test system for the teflurium corrosion of Hasteloy N
1 The teflurhun activity must be appropriate reproshyducible and known
2 The tefflurium must be ddivered uniformly over the sm|jie surfaces and at a rate sufficient to prevent excessive testing times
3 Preferably the system should operate under invarishyant conditions during the test run
4 The system must be relatively cheap simple and easy to operate
in the MSBR the production of tellurium per time unit wnl quickly reach a constant value and in due time a steady state will be reached where telurium is reshymoved from the melt at a rate that equals the rate at which tellurium is produced
i to reacting with me Material of which the circuit is constructed leBunum could be reshy
moved by several means which mdmfc the foetamug
1 The | ining system Since the MSBR is to be equipped with a pm ceiling system to remove Gemm product telufium might be effectively removed from the salt by appropriate measures
2 The gas phase If the gas phase is contacted with a getter such as dumnium wool the tchwrimn activity m the men ought be kept dose to that defined by thelaquo
^Cr TTe(k)^ TeltgH ACrlts)
Thu activity is sufficiently low that Hastdoy N would not be attacked
3 A getter immersed in the salt mdt Obvious disshyadvantages of this arrangement would be the probshylems of mass transport in temperature gradients and the lack of a candidate material
Until the steady-state condition in an MSBR is more dearly defined it is impossible to state the likely tellushyrium activity It is only known that in the MSRE stanshydard IfasteOoy N was embrittled (probably by tellushyrium) In the MSRE the steady-state tellurium activity - if ever reached - probably was defined by gas phase removal and was likely rather high
Until the steady-state situation in the MSBR is deshyfined it must be assumed that one must deal with the MSRE condition under which standard Hastdloy N is embrittled In order to define this condition we have tested several systems with defined tellurium activities with regard to their behavior toward HasteHoy N
1 equilibrium mixture of C^Tejfs) + CrjTe4(s) 2 equilibrium mixture of NijTej(0j 41 at 7 Te) +
NiTe 077J(7I ^ 437 at Te) 3 equilibrium mixture of CrjTe 4(s) + CrTc6(s) 4 equibbriun lixture of Ni 3Te(s) + Ni(s)
The systems are arranged in sequence of decreasing Te 2
activity as determined by isopiestic experiments Typical corrosion experiments were contacted at 700degC for 250 to 1000 hr The arrangements were by isothermal gas phase transport of Te in previously evacuated sealed-off quartz ampuls by embedding the specimens in the mixtures and in the Cr2Tej-CrTelaquo and CrjTe4-Cr4Te6 cases by transport in molten salt
The most pertinent results are as follows
I Hasldloy N samples exposed to NiTej(s) bull Ni(s) (system 4) did not show intergranular cracking This is promising because if one a n establish a steady-
M l
dak luaawiun m which the telahaa activity is kwcr HOT OOI aefaed by das system staadanJ Haacaoy N wtl wot be eaaaittled
2 Sysaeas I awl 2 have teMaaa activities thai are loo high Ibex sysseas corrode Hasseaoy N sevcaeh water af the experiaeatal w w y a w i aad
3 Systea 3 fCrjTelaquolts) + CrTeraquoltsti SIUHH proaase as a iraariaa-deaivery actboa a aohea sansacc it B saffvseatry corrosive to cane aterpawatar cactoag of thk-caoy N b a docs aot fora acactioa layers
It is of value to note dot the systea Cr7Te(s| bull Ctls) has a tehaiaa activity that B mar lower thaa the systea NiTe2(s) fifs) l as systea abo is proa-isag since lagh surface duoaaaa aiebt be used a a tdariaa getter a the fas phase Experiments are water way to measure the telariaa activities of the above systems
611 OKRATIONOF METAL TEJXURJUM-SALT SYSTEMS
J R keissr J Brynesud J R DiStefaao EJLawrcace
The discovery of Jtatk intergranular cracking of HasteBoy N parts of the Molten-Sail Reactor Experishyment which were exposed to furl salt led to a research effort which identified the fission product tellurium as the probable cause of the cracking Experiments showed that HasteBoy N specimens which had been dectro-plaied with tellurium or exposed to telariaa vapor exhibited shallow intergraniaar cracking like that of specimens exposed in the MSRE Subsequently a proshygram was initiated to find an alloying modification for HasteHoy N which would enhance its resistance to teiu-rium The resistance of these modified alloys to crackshying is measured by exposing specimens to leaiirium vapor deforming them and then evaluating their surshyfaces by metallograpruc and Auger methods However the chemical activity of tellurium in these experiments raquo significantly higher than it was in the MSRE In order raquoo simultaneously expose specimens to the combined corrosive action of molten fluoride salt and telurium at a more realistic chemical activity a method is being sought for adding tellurium to molten salt in a manner that would simulate the appearance of lefurium as a fission product Experiments have been started that wia permit evaluation of several methods to determine whether they will produce the desired conditions
61 II Teaaraan Expcnacatal Pal I
Tellurium experimental pot 1 was built to evaluate the use of lithium telluride as a means for adding lefu-
riaa to safe Has pot laquoRg 632)aVws t d a a a lobe
BaaaaWC PJKBTBBH t a W t m a f f e a l tan a a r a n f H M K I BBBEBY a a a V aj w^ laquo ^ n i w araquovraquo ^ ^ p a t s waaaaajaa ^^a avaa BPUiawavww a a wuvu a a a i aaawaa
through Tefloa seals aad are used Or delect aad aeaa JK
14 The Nrtimdash laquo fan far As nacnacw raquo raquo fnfmt4 bully vannr t JHB ncaacny i mc ootiiuuucvKai B a M i i o o bull a t m4t traquo aryci raquo4 ) b M r
102
I bull UF-lef -ThF 4 (72-16-12 mdk mi m tern- A rfastetoy N pat was filed with the salt LiF-ftcfV latoSOTC ThFlaquo (72-16-12 aaok ) mi the temperature conshy
trasted at 700C After a sample of the salt had been lixTe which w pscpMcd hy the tafcea CrTelaquo was added mi a M I Hasteaoy N sheet
(Sect 31) hat i i i j two pdhsts specimen was inserted hMo the salt After 170 hr the a total of 0170 g of l i jTe were added to tjrrrwnrn was reamed and after 250 hr a salt simple
I of saw taocaoJwwkji enmamiua of the salt wax taken The teaaperatare was thea lowered to 650degC of oar ftadynra Chtaaitijr Draw gave aad a day user a sab sample was again takca This of the preseace of irlmiiia (Sect S3) xoacace was thea repeated at 600C Next the salt
dace aancIiiTepdkts west added aad te-ptrataie was rawed to 7O0C Cr Te was added a sawffc of Ae salt was takes for choanal analysis aad aaother Hastetoy N spedaaea iasertcd Ihe sped-Thre- addaaoas of CrF 2 totaling IJ2 g were thea a n was reasoned aad sah samples were tafcea under the aanle roauaed hy the aaaaaoa of theee awe li jTe same tjaw4eaagteratare coaditioas as discussed abouc
A anal iddirtja i nailing of 02 g of 10 was The two Hasteloy N spediaeas we submitted for Anger examination No were detected bat twdeace of tdariaai in the grain
foaad (Sect 612) The results of thr of the salt snaade are shown in Table
614 Tcaaraaa ooaceatratioas at 700C were not as bjgb as was expected bat the tact that some tct-irium was ia solution is deaaoastiated by the teHariam found oa the tpniannt Addrtioaal CrjTe was added to the
two salt samples were take lYriincaary that the soJatioa any not lane been
i the first series of salt samples was ulten the solafcarry measurements two tensile
icre exposed to the sah-CrjTcj solution Both specaaeas oae of rcfabr Hastcloy N and oraquo of lift Mraquo-07 Ti uwdrfied Hasteloy N showrd a
after 500 t_r exposare at 700C After iheregabr Hastetoy
N jpuinun was obatmd to lane agaificaatty more aad cracks than dhJ the modified Hasteloy N sped-
i (Sect 614)
r6M
611J
The adfciua of a CrjTty or CrgtTlaquo4 at anj stall aaothtr awaVod for
toaHaamMSMfanadtiraaesceai of ehraawam idhaldt is bullanafaajsi aat acttwiy of
at the adt wM he otnunaat pro-
To at which canter of thaat chro-
bullw wWwWwaPpPIbull VraW) ^ppaaar bull ajwPTff
of the chromta Mftaridat as s faac-
Tlaquoaa rnmauddNoanan M )
Moaa^aVStwMw bullnoTci After
OTe After
Ctlt tUHiam
im Tlaquo 5 0 4 4
Tlaquolt5 Cr7S
Tlaquolt5 CrlaquoJ
656 Tlaquo 151 CrIOS
Te75 Crl20
tan Tlaquolt5 rr
Tlaquolt5 OBJ
103
The experimental assembly is being used to expose standard Ifasteiloy N specimens to salt containing Cr Tej to obtain data on the extent of attack at 700degC as a function of time
611J Telwnum Expctunxwtal INN 2
When a technique for introducing telurium into salt at an acceptable chemical activity has been developed a method will be needed for exposing a large number of specimens to salt-tellurium solutions A Urge experishymental pot has been constructed for this purpose The pot has a stirring mechanism facilities for introduction of electrochemical probes and sufficient accesvi to allow dmulianeous exposure of a large number of specishymens Operation of the system will begin when a satisshyfactory tellurium addition technique is available
612 GRAIN MUNDARY EMHtlTTLpoundMENT OF HASTELLOY N BY TELLURIUM
R E Clausing L Heatherly
Auger electron spectroscopy (AES) is a powerful technique for studying grain boundary embrittlement of Hasidloy N by tellurium The recent development of the technique to permit AES analysis win a small-diameter (--5-fi) electron beam to excite the Auger elecshytrons of a specimen surface has made truly microscopic analysis possible1 5 The development of techniques for scanning the beam and the development of electronic data processing equipment have continued to be a censhytral pari of our efforts As the techniques improve our ability to see the details of the telurium embrittlemenl process improves dramatically We can now not only provide a qualitative image of the elemental distribution on intergranular fracture surfaces at a magnification of several hundred limes but we can aho provide a semishyquantitative elemental analysis as the beam it scanned along a line across the sample However it is not presshyently practical to provide a quantitative analysis along a line across an rntergranubr fracture surface since Auger intensities at each point OR a rough surface vary accordshying to topography This effect can be corrected in prinshyciple by a normaliation technique but data for each point must be normuhad mdrvKJuaRy and the present equipment cannot handk the volume of data required The data presented below are typical of several samples of lefluriurn-envbrittled HnHcRoy N that were examined recently These samples are being studied in various
15 R I ltlMlaquonf ami I Ikjihrrly VWT ftn^wm Srmi mmu rmtr Rrp fth J bulllt ORNI -5ltM7 p MM
pans of our previowtty outlined efforts to understand the tellurium embrtttkment of nickel-based alloys The sample chosen for the present discussior demonstrates our state-of-the-art capabilities and limitations and at the same time provides some new insights into the nature of the tellurium embrittlement of Hasteloy N
A sample of Hasteuoy N that had been exposed to tellurium vapor at low partial pressure for SOO hr at 700degC was fractured in the AES system and the resultshying fracture surface was analyzed using Auger electron spectroscopy The fracture surface is shown in Fig 6 3 3 The scanning electron micrographs made by Crowe reveal that intergranular fracture occurred along the edges of the sample and that the central reejon faded in a ductile manner One fairly large area of ductile shear can be seen Three types of Auger data presentations are used below imaging line scans and selected area analyses The first is qualitative while the second and third are progressively more quantitative
Figure 634 is an image obtained using the scanning beam in the AES system and the absorbed sample curshyrent to produce the image contrast It is similar to the scanning electron micrograph (la) but because of the larger electron beam and the different method for proshyducing the image contrast the resolution in Fig 654a is poorer and some distortion is evident Nevertheless it is relatively easy to correlate the features shown in Fig 634a with those in Fig 633a Figure 6346 is an image of the same area shown in Fig 634a but with image contrast produced by the tellurium Auger signal A careshyful comparison of the areas of high tellurium concentrashytion with the areas of intergranular fracture shows that a good correlation exists between the two No telurium can be detected in the regions of ductile or shear fracshyture Figure 6 3 5 b a series of line scans showing the peak-to-peak intensity of the Auger rignah for nickel molybdenum chromium and tellurium as the electron beam was scanned along the path shown by the bright line Hi Fig 654a Some of the observations that can be made are (I) The intensities of the Auger signals are influenced considerably by topography that is some features such as the shear region between feature gt and the ieRuriumlaquombrittled region below it show lower Auger emission for al dements (this dependence on topography accounts for much of the jagged nature of the line scant 12) The lefurium concentration is quite high in the region of mtergranuiar fracture near each original surfaor ltJ| There is a definite tendency for the concentration of molybdenum to be higher in the regions of intergranular fracture (41 The nickd and chromium concentrations are in approjumatety the same ratio throughout the scan
104
ltaraquo 2nox ifrgt sonx laquorraquo nmraquolaquo wgt torn lto jonox Tt
105
Y-133510
Crack
Te Ertrittled
I i raquo i gt MICffOftS 375
j j TTT90raquoi i i S i i i r r i I005 INCHES 0015
F fcM MI l i w u i rtmw bull laquo raquo laquo gt mm to raquo AES Fht brnrfii wiiiul law dnraquoraquo the path irf ibr IMW laquo M 4laquol HJaMMrt ftftom in laquo fc-35 (M h M p e f otoMawajgiMM
NJ 4t M M n Aapjf bull bull bullgt pMaJwt nartmrt The onkriiiM fraai tuwJjiy ngtam m i to th
106
Traquo-laquo4T
Flj tSS Anger ajnJ Menrities for scans atony Ike path wdicXcd sn Fjsgt 6S4 The vertical axis is displaced and the vertical scales arbitrarily varied to permit a qualitative comparison of the variations of Ni Cr Te and Mo as a function of distance along the scan line The tones and features identified along the horizontal axri are also identilied in Fig 6_S4raquo and c The AES analysis of the regions bbeied area I area 2 and area 3 are given in Table 615
Another observation based on the detailed examinashytion of this and other samples is that the tellurium conshycentration hi the grain boundary is not a monotonically decreasing function as one proceeds inward from the original surface On nearly all of the embrittled samples examined thus far the tellurium concentration is uni-formnJry high throughout the embrittled area as for example is shown on the right in Fig 655 (The signal intensity on the left is strongly influenced by toposhygraphy- If this effect were removed by a normalization process Ms area would have a more nearly uniform composition similar to that on the right) The high relashytively uniform telurium concentration in the embrittled regions suggests that either a particular grain boundary phase of fixed composition may exist or that the tellushyrium atom fill all of the appropriate grain boundary sites in the embrittled region Sputtering this fracture surface (and those of similar samples) to a depth of a few atomic layers (3 to 10) reduced the tellurium conshycentration to below I at showing that the tellurium is concentrated very sharply in the grain boundary it is
therefore unlikely that the tellurium present in the grain boundary exhibits the properties of a bulk tdluride The molybdenum concentration remained high during sputtering operation indicating that the concentration of molybdenum is high in the bulk phase perhaps in a phase that has precipitated in the grain boundary
Table 615 shows quantitative selected-area analyses made in the three regions of the sample indicated in Fig 654c The compositions have been normalized to equal 100 at in each row The three rows for each area are obtained from one Auger spectra but some elements were ignored in the first two rows to make changes in the relative amounts of the other elements more obvious These results confirm the above conclusions and show ( I ) that tellurium is present in relatively large amounts in the embrittled regions and (2) that area 3 which is near the extreme of the depth to which the tellurium penetrated contains about as much tellurium as area 2 which is located near the center of the upper embrittled region Regions 2 and 3 are both enriched in molybdenum and carbon M indicated in the line scans
107
r4IS Cuaiummnofi ofaHamdmyNa
tor Suffer at 7 laquo r c
Rezwn Composition in laquo5r
Ni Mo Ct O
Composition in the lower repon area 3 imiertranitU fracture)
Cohipositioi in ocntral region area I (dacine lnlaquoiuregt
Composition in ike upper repon arcs 2 imlergwiutar fracture
70 1 11 M 1 10 9 40 II 6 6 75 16 9 75 16 9 61 13 8 64 25 12 58 23 II 8 42 17 8 6
33
13
I I
Areas identified in FBJ 6-54r The composition in each row is normalized lo cquai 100 at ri The three rows
lor each repon are from the same data but are normabted so as to make changes bulln retain amount of the dements more obvimn For convenience and consistency in repot inc data we astame the AF5 spectra tfaol Pabnbetf et aL Htndhook of Anger Electron Spectroscopy Physical Electronics Industries Inc Fdiru Minn I972l are accurate and directly applicable to our data Elemental sensitmwes are taken directly from the spectra presented m the handbook with no attempt lo correct for chenaca effects line shape matrix effects escape depth or distribution of dements as a fraction of depth in the sample The analyzer used is Varian model 981-2707 operated with an SOOOeV electron beam energy
The above results suggest the need for a detailed examination of the causes and effects of the high moshylybdenum and carbon contents in the grain boundary region and abo an examination of the irnphcations that the presence of a two-dimensional tellurium-rich grain boundary phase may have on the time dependence of tellurium penetration into the alloy
613 X-RAY IDENTIFICATION OF REACTION PRODUCTS OF HASTELLOY N EXPOSED TO TEIXimiUMCONTAlMNC ENVIRONMENTS
D N Braski
Hasteiloy N and several modifications of the alloy have been exposed to tellurium to determine their rda-ive susceptibilities to intergranular cracking Different nethods for exposing samples to tellurium have also
been studied in an attempt to develop a suitable screenshying test for the alloy aVvctopmenl program Some specishymens were exposed directly to tellurium vapor at 700degC while others were subjected io attack by nickel or chromium teBurides at 700 and 750V respectively This section presents the results of x-ray diffraction analyses of reaction products producerl during the tests Knowledge of the reaction products akts in evaluating a
given method of tellurium exposure and may provide information relating to the mechanisms of intergranular cracking
A number of Hastefloy N tensile specimens and flat x-ray samples were exposed to tellurium vapor at 700 SC for 1000 hr in an experiment conducted by Keimers and Valentine The specimens were positioned in the top portion of a long quartz tube having a smal amount of teiurium at the bottom The tube was evacuated backfilled with argon and placed hi a gradient furnace with the specimens at 700C and the trtiiium source at 440C With this arrangement teuurium vapor diffused upward through the tube at a rate dependent on the temperature difference between the specimens and the tellurium CM)Xgt5 mg TehrV At the end of 1000 hr exposure the specimens were covered with a very fine hairlike deposit similar to that observed previously in creep tests at 6 5 0 C 7 The results of x-ray diffraction analyses on these deposits are given in Table 616 The first alloy listed is standard Hasteftoy N while the other three have titanium and niobium additions The main
16 A D Keimers ami D Y Vatentme MSK Ammjm Semi IMII rrogr Rep Feb 2S 1975 ORNL-5047 pp 40 41
17 R F GeMhach and H HensonMSK hvpmm jViinwm frogr Hep An J I 1972 ORNL-4832 pp 79 86
108
TaUcfclt X-faydifTrartiMi malts fori IO0O brat 700 C
Hat number t lt aftoyinx
additions to nominal HasteBoy N composition
Method of tellurium expovire
Surface reaction products
405065 None kelmervVaknime experiment^
NiTe CtJe
472-503 M r Ti kctroerv Valentine experiment4
NiTe
470-835 0711 Ti 261 Nb Kebners-Vakn line experiment
NiTe CrTe
IK) 841 Nb Kdmers-Valeniine experiment
Ni rTe
474-533 201 Ti Brynestid low Te ac irrily exposure NiTets) + Nitsgt
NiTe unidentified substance
405065 None Bryncstad LiO + CrTe
N i T laquo + N i T e
V D Kdmersaad D Y ValentineMSR Fran Srmunnu Prop Rep Feb 28 1975 ORNL-5047 pp 40-41 J BrynestadVSR Prognm Senaamu Prvgr ltep Feb 28 1975 ORNL-5047 p 102
reaction product was NijTe 2 which was detected on the surfaces of all four alloys (NijTe was found on earlier samples exposed for shorter times in the same apparatus) X-ray lines which could be indexed as CfTe4 were also found on standard Hastelloy N and on the alloy modifkJ with 071 Ti plus 263 Nb The Cr jTe 4 interplanar spacing and relative intensities were calculated by H L Yakel Metals and Ceramics Divishysion from the crystallographic data in ref 18 The presshyence of CrTe4 in the reaction layer is reasonable beshycause both chromium and tellurium were detected pre viously on Hasteiloy N exposed to nickel telluriddes by electron mkroprobe analysis1 In addition chromium tdlurides were previously identified by x-ray diffraction on Hastelloy N exposed to tellurium vapor17
Brynestad20 exposed 2 Ti modified Hastelloy N specimens to a low tellurium activity (Ni3Te + Ni mixshytwe) at elevated temperatures The specimens were first placed in a quartz tube and the Ni JTe 2 + Ni powder mixture packed around the specimens The tube was then sealed off under vacuum and placed in a furnace at 700degC for 1000 hr The reaction products obtained in this test also contained NijTe2 but the remaining four lines could not be satisfactorily indexed to any of the
18 A V Berfaul G Rnull R Aleonard R Pauthcnct M CVvTctou and R Jansen Structure Magnet iqucs de CtX 4
raquoX = S SeTeh Phvs Radium hi)582 95 (1964) 19 D N Braski O B Cavin and R S Ctmae MSR Prltt-
gnm Semtannu Fmgr Rep Frh 28 1975 ORNL-5047 pp 10$ 09
20 J BryncMad MSR Program lemktnnu Pmtr Rep Frh 28 i975 ORNL-5M7 p 102
Ni Cr or Mo tellurides The unusually broadened x-ray diffraction peaks suggest that a complicated teluride such as Ni-Cr-Te may have been formed In another tellurium experiment Brynestad exposed a standard Hastelloy N tensile specimen to a melt of LiCI containshying Cr 2Te 3 (solid) at 50degC Some Cr 2Te dissolved in the LiCI melt and reacted with the HasteUoy N After 146 hr the tensile specimen was removed and the flat surface on one end was analyzed by x-ray diffraction The results (Table 616) showed that Ni3Te2 and NiTe0 were produced
In summary these tests have shown that the primary reaction product between Hastelloy N and tellurium near 700degC is NijTe X-ray lines corrsponding to Cr iTe 4 were also present in patterns from the surfaces of several Hastelloy N alloys exposed to tellurium vapor at 700degC Exposure of Hasteiloy N to tellurium at low activities (NijTe2 + Ni mixture) may have produced some complicated Ni-Cr-Te compounds in addition to NiTe2 as evidenced by the unusually broadened x-ray lines
614 METALLOGRAFHIC EXAMINATION OF SAMPLES EXPOSED TO
TELLURIUM-CONTAININC ENVIRONMENTS
H E McCoy B McNabb J C Feltner
Several samples of modified Hastelloy N were exposed to tellurium-containing environments They were deshyformed to failure at 2SdegC a procedure v-hich forms surface cracks if the grain boundaries are brittle a
109
metallographk section of each was prepared to detershymine the extent of cracking- These tests hawe two objecshytives The tint is to dewlop a method for exposing samples to leBurium to produce a reaction nte comshyparable to those anticipated for an MSBR This rate is thought to be a flux of teOurium of about I0 1 atoms cm 1 sec- The second is to compare the cracking tendencies of arious alloys of modified HasteBoy N
A new technique developed for measuring the extent of cracking is more nearly quantitative than that used previously In the new technique a mounted and polished longitudinal section of a deformed specimen is viewed on a standard metallurgical microscope The eyepiece has a fiar which can be rawed to various locatiom in the field being viewed The filar is attached to a transshyducer which produces an output voltage that is a funcshy
tion of the location The output signal is interlaced with a scull computer which WH on command compute crack lengths and several statistical parameters The information is displayed on a teletypewriter The cracked edge of the mounted specimen is scribed every 01 in_ and the operator measures a l cracks in successhysive 01-in intervals untl at least 30 cracks have been measured The computer then calcinates and displays the average crack length the maximum crack length the standard deviation and the 95- confidence interval A typical scan requires about 10 mm and is considershyably faster than other methods used thus far
The experimental conditions associated with the ten experiments to be discussed in this report are summashyrized in Table 617 The chemical compositions of the alloys studied are given in Table 618 In all cases the
T J U T pound I 7 Cenoal4cxiiftmm ofTe-HaMenoy N a y w t t
Experiment IXcsipna (km Experimenters Exposure
conditions Alloys
bullMinded Genera
75-1 Brynesud UCl + Cr Te for I 4 6 n r a l - 7 5 0 C
405065
75-2 Krimcrs Tc vapor for Valentine |l)00 bral 700 C 405065
470-835 472-503
ISO
75-3 Bryneslad 250 hr at65ITC 405065 pa-kedin( r Te 474-534
474-535
75-4 Bryncstad 200hraf 700 C packed in Cf Te
405065
75-5 Biyncstad 504 hr at 700 C 405065 Keiser in s i t bull Cr Te 470-R35
75-6 Brvnestad 000hra l700C with vapor above Cr Te 4
405065
75-7 Brvrrslad 1000 hral 700 C with vapor above Cr Te
405065
75-8 Brynestad 1000 hr at 7 0 f l T laquo i l h vapor above J gt nH-kel tellurides
405065
75-9 McNafcb 250 hi al 7laquofC in 405065471-114474-534 McCoy vapor above Tc al 474-5356006006263
300 C I H 237295 297 298 303305306345346 34734821543469-344 469-648469-714470-786 470-835
75-10 McNabb 250hra l700 C in 40506521543 345348 McCoy vapot above Te al
300C 4 1 1 4 1 laquo21424425
Heavy reaction lay en
Whisker growth evidence of inhomopenoas reaction withTe
Heavy reaction layers
Heavy reaction layer
Reaction layers
No visible reaction ayers
Shallow reaction layers
No visible reaction layers
No visible reaction layers
No risible reaction layers
See Table 618 for chemical compositions A D Kilmers and I) Y Valenlnc M$R Program Srmimmi FriffT Kip Feb -X V75 ORNI-5047 pp 40 41
110
t6lt
Heaimoabei Mo Cr Fe Ma C Si Ti Mb At Of her
62 134 752 a 020 0042 001 a 19 63 145 7 J 3 a 020 0135 001 a 25 l raquo 12 70 0040 022 0046 OJOI lt002 184 ISI IS 684 0054 0-23 045 001 050 185 003 W 237 20 67 43 049 0032 m 004 103 lt0-05 295 14 806 402 0 28 0057 lt002 lt002 085 0 0 5 296 15 809 396 028 0059 lt002 lt002 12 02 W 297 29S 303
2 1 20 20
70 70 70
40 40 40
02 02 02
0 0 6 006 006
002 0J02 0J02
024 lt00I
049
057 2J0 0J4
305 12 825 416 022 0072 009 088 I J 306 06 804 311 018 0065 027 001 OSS 345 IJO 71 38 026 005 022 002 045 346 110 67 37 018 005 048 002 049 347 20 7 43 025 005 047 lt002 088 34S 411 4 l i 42 424
20 20 20
120 120
72 70 70 70 70
007 a a a a
019 02 02 02 02
005 005 005 005 005
047 e a a a
lt002 a 1 0 219 18
042 115 113 104 134
007 010
42J 120 70 a 02 005 a 19 048 008 405065 160 71 40 055 006 057 lt00I a lt003 472-503 129 679 O089 lt00I 0066 0089 216 005 009 471-114 125 74 0062 002 0058 0026 175 a 007 474-534 1166 712 006 lt00I 008 003 20rgt a 053 014
0013 La 474-535 1179 730 005 lt00I 008 003 213 a 055 010 W
0010 La 003 Cr
600600 160 80 019 027 ltlnconcl600gt 469-64 128 69 030 034 0043 a 092 195 a 469-714 130 85 010 035 0013 a 08)) 160 a 470-835 125 79 068 060 0052 a 071 260 a 00311 Hf 40-76 122 76 041 043 0044 a 082 042 a 0024 Zr 469-344 130 74 40 056 011 a 077 17 a 0019 Zr bull21543 124 73 004 008 0050 0019 a 0 7 002
Not analyzed bur no intentional addition made of this dement
Not analyzed but nominal concentration indicated
sample was a small tensile specimen 56 in in diameter X 1 in long having a reduced section in in diameter X I in long All specimens were annealed I hr at I I77degC in argon prior to exposure to tefliirium The results of crack measurements and data resulting from the tensile tests at 25degC that were used to open the embrittled grain boundaries are shown in Table 619
Experiment 7S-I was run by Brynestad and involved a sample of standard Hastelloy N that was immersed in LiCl saturated with C r T e for 146 hr at 750degC The specimen formed a heavy reaction layer (Table 6 7 ) but lost weight (Table 619) Figure 656 shows that the reaction was rather extensive with some obvioia grain
boundary penetration which resulted in extensive crack formation in the deformed section The extent of reacshytion in this experiment was higher than anticipated for an MSBR and therefore it is not believed that the experimental conditions employed constitute a good screening method
Experiment 75-2 was run by Kelmers and Valentine and the detailed results were described previously2 All samples lost weight in this experiment (Table 619) Although the samples had more reaction product en
21 A D Kelmer ind D Y ValentineWW Program Smi-anmi Progr Rep hth 28 1975 ORNL-5047 pp40 41
Tabic 619 Inlf(granular vracfc formation anrt loniU propcrD of raquomnllaquoraquo oPlaquoraquovd In ulltMlum and ilralnad lo faHurv al 25 V
ffimmti H M I MMttof
CilaquockiMui k |0gt
C m k t f w C i K k t c m
D t p In ) SlWMbi 4fvulMgtn
1raquogt
CMflOIIWt W I U M I
I M I
W f laquo k l bull lung lmlaquol
VMM t u t u
ltbullbull rail
U I W M I f M M HltMH
t l O 1 ptl)
f l M I I M f H l t U
lt I 0 p i l l
U m f w m f lMUt lWH 4 I 0 ^ I raquo
P l M I W f HIM
K n l i w i i M M M M
11 MMraquofclaquo
H M I MMttof CilaquockiMui k |0gt
C m k t f w C i K k t c m A M I i f M W I R H U H
SlWMbi 4fvulMgtn
1raquogt
CMflOIIWt W I U M I
I M I
W f laquo k l bull lung lmlaquol
VMM t u t u
ltbullbull rail
U I W M I f M M HltMH
t l O 1 ptl)
f l M I I M f H l t U
lt I 0 p i l l
U m f w m f lMUt lWH 4 I 0 ^ I raquo
P l M I W f HIM
K n l i w i i M M M M
11
5 1 40505 ) | lgt 111 101 lt 1 7 1 4 ) 1 I T 4 1 1 1 4 ) M i l gt I 4 HI raquoJ-1 4 0 5 0 5 5 ) 0 1 1 4 t gt 7 5 7 1 1 1 4 5 1 0 SI 7 1 ) 4 7 I I 71 4 0 4 4 1 1 43 1
470-1)5 17 A t 1 7 7 0 I S 4 4 1 1 1 7 7 1410 l ) t laquo 4 1 5 44 0 ) S ) 4 7 ) 5 0 ) 100 I I I gt)) raquo7 0 1 4 I I sraquolaquo 1 5 ) 1 1 1 ) 0 ) l lt 4 0 4 410
iao t ) 15 1 4 ) 0 1 D l A l 47 5 4 5 1 1 4 ) U S I M l ) t 1ST 7 5 1 40515 140 laquo5 17 1 4 1 1 0 17 117 4 7 uto 1 0 0 4 0 1 414 4 1 4
474lt5)4 110 17 145 1 7 4 5 1 4 145 S t 114 0 1 0 0 411 441 S I T 4 7 4 5 ) 5 1 ) 0 bull I 1 0 ) M 4 5 4 1 1)1 4 S 4 not laquo 7 4 7 4 lot S 4 )
7S-laquo 40505 4 1 0 5 7 0 11114 l raquo ) S l 1 1 1 1 1 1 ) 5 11 ) 15 1 bull raquo I 7 7 1 1 ) l 44 1 44 0 10) 7 I N M ) H I 1 1 1 gt I 0 ) ) i ) 1 4 4 1 4 4 1 0 7 5 5 405115 170 14 4 1 5 raquo 0 I S S 1 bull 0 1 5 0 111 1 1 1 7 ) gtS ) 7 1 1 1 1
4 7 0 laquo J J 10 71 ))) 14 7 1 0 1 I t S I 5 1 1 I M 1 I M 7 17 0 ) 7 1 1 4 7 - 40505 115 15 I ) 1 1 4 1 ) 1 4 4 0 bull 001 S i t 1 1 1 ) 1 1 7 1 4 0 4 4 1 0 ))raquo 7 J 7 40505 510 )ogt 4011 1 0 1 4 1SS k i t 1 1 4 ins ) I 7 ) 4 ))gt 7 ) 1 40505 ) 0 141 5 5 bull lll 1 1 7 ) )raquo) Sl l 1 1 ) 1 1 1 7 4 4 0 0 414 5 1 7Jraquo 40505 H O 141 4 1 7 5 ) 151 I I I 7 5 1 1 1 7 ) 1110 M S 41 1 gtraquo4
4 7 1 0 1 4 l i 7 ) ) 7 4 )laquo I D 4 4 bull 1 4 4 7 1 1 ) 4 105 0 laquo raquo l 5 4 1 4 4 4 7 4 5 ) 4 ) 0 14 1 1 5 4 5 5 107 ) 1 7 I t l i t 1114 4 gt gt 45 S 411 15 140 I S 10 1 J M raquo l J7 0 5 1 5 1114 I D ) 4 t ) 4 1 ) 4 7 t HI 15 10 1 7 1 U I laquo I I bull ) 0 )raquo 1 0 1 7 4 U l gt 7 I S T )
M S 100 )raquo )raquo 4 l 1 1 1 1 4 bull 0 7 1 1 7 I I 1077 M l 41 I 4 raquo ) H t i l l ) 1 0 7 441 100 ) S bull 0 4 551 I l l 1117 41 1 44 7 4 7 1 M l 4 l I S ) l i 0 ) M l 1 1 ) 4 1075 4 1 5 4 5 511) J41 170 0 raquo I I I ) 7 ) l i i bull 1 S l l 1)1 1 l l t l 4CI 4 ) 1 4 ) 50 450 177 11 o 1 7 7 ) i i bull 0 1 too 1)00 1 1 1 17 4 4UI 4 ) 4 50) 450 l lt 1 4 1 1 raquo l i bull 1 1 I t 1 111) 1100 471 445 4 0 raquo 7 J i l l 111 1 1 0 4 1 0 1 1 u bull 1 1 t l 1 l i t ) 1 1 7 1 ) S gt ) T 4 4 1 5 15 15 10 10 1 1 7 ) i s 1 5 5 ) 5 1 1 ) 1 I M S 4 gt ) 4 4 4 4 4 1 )7 IS )) 14 1 ) I S I S i 0 5 1 4 l i l t I M S 4 ) 5 4 4 ) 4 4 505 H O 141 I t ) 1 7 1) 1 4 bullUS 5 ) 1 D t S 1 1 7 ) 4 4 1 4 1 4 7 7 M l 1)0 D O 1 7 ) 107 bull 4 1 1 bull 0 4 7 1 ) l l ) t 1104 4 1 7 4 raquo 4 7 11 110 17 1 7 1 1 1 7 ) 7 7 4 M I 1171 m i 4 1 4 4 S I M S ] 10 11 1 gt 1 4 0 4 4 5 IS 1 5 4 7 117) 110 1 4laquoT SOT 4 1 1
) 440 17) 117 1 7 S ) 1 I S l l l ) ) 4 111 7 gt J ) ) l o 41S 4 4 4 1 ) ) 0 1 ) 0 I I I 4 ) ) 7 4 1 bull 0 1 I I 1)1T 117) 4 ) 7 4 1 445 4 7 | 4 1 ) )) 114 5 0 4 1 1 4 5 bull 0 0 1 4 1 1117 l i t ) 8 ) 7 Hi 4 ) 4 4 7 0 O J ) )bullbull 1 1 4 7 SO 1 0 0 ) 5 5 IJ75 1)04 414 477 4 5 4 7 0 7 t )) 1 ) 1 ) 1 5 7 1 14 S 7 ) 0 ) 4S l i t 7 1 0 7 ) 5 0 4 S I 7 40 1 4 5 4 4 )raquo 141 l 171 V I 1 ) bull 0 07 5 1 7 1 ) 1 1 1 1 0 ) I 0 ) raquo 7 414 4 1 1 5 4 ) bull5 )) I I 1 4 4 4 1 17 11 45 4 not M I MT 5 7 )))
75 10 40505 M O I ) ) 177 4 1 ) 7 1 1 bull 0 0 4 5 ) 1 1 ) 1 4 1 1 ) 0 4 0 4 gt I 4 4 0 415 ) 0 0 I I I 17 1 54 1 I I 1 4 1 bullOS S l l l i t a 1 1 7 4 7 411 411 415 140 5 1 1 7 5 1 0 1 ) 4 ) laquo 0 0 l t i l l i t ) I I I ) 4 1 ) 410 4 7 411 M O 1)5 M4 raquo0 l 1 0 1 1 4 0 0 ) sso 1 1 7 111) 4 ) 7 4 5 4 4 1 4 414 4 ) 0 1 1 7 501 14 1 0 0 ) bull 7 4 l ) raquo ) 1 ) 1 7 44 1 411 gtbull) 11 101 1 1 17 1 0 54 0 74 bull0 1 1 ) 4 1111 1 1 ) 0 4 7 1 SI 1 1 1 7 15 M 10 I I I 1 5 1 ) l bull 0 1 5 ) 4 m i 1117 4 1 4 4 4 4 47 ) 541 M 1 ) 1 1 M l 71 15 bull 5 4 1 i n 107 1 44 1 4 7 4 54T M 5 15 5 raquoraquo 141 gt) i n bull 0 0 1 5 1 1 1 4 1074 4 4 ) 4T4 4S4 415 M 11 105 117 5) I S bullooi 5 ) 0 i n I IS S H 4 4 44X1 411 1 ) 141 ) 5 laquo 1 5 1 bull 14 4 1 1 1 1 ) 4 bull T I S I M l 5 ) 4
4 1 1 5 4 ) 17 7 10 1 ) 7 I I gtraquo bull 1 4 7 ) I D 1014 S I ) 1ST 5 ) 7
4laquou i MM tun bull 15V al bull tiiaM M M ul 0044 Mgt 1uUl laquomlil raquof yfmmtri 1 1 l o t 1 )
112
raquo gt laquo laquo bull
(b)
pornnaof
0-010 in 0 25
U t a M H I i th) tdft oi ureaed poriioa of 1
llaquowraquoCr Tca i7Mrci IflOX
HkrltlaquoiE ytoT
one end than the other the extent of lt icjaunably uniform Typical plsotonucrognphs of the (oar materiab are shown in Fig- 637 Aloys 40506S (standard) and 472-503 (216 Ti) formed extensive cracks but aloys 470435 (071 Ti 260 Nb) and 190 ( I J49 Nb) were considerably more resistant to cracking
in experiment 75-3 three samples were packed in CrTe grannies for 250 hr at 650degC The samples formed heavy nonadherent reaction products and lost weight (Table 619) All three materials formed extenshysive cracks (Table 619 Pig 638) with the depth of cracking being slightly less in the two modified alloys (474-534 and 474-535) than in standard Hnstdfoy N (heat 5065) However the extent of reaction is too high under these conditions for the results to be meaningful
bi experiment 75-4 duplicate samples of standard HastePoy N (405065) were packed in granules of CrTe4 and heated 200 hr at 700degC The samples formed nonadherent reaction firm and lost weight tarshying the test (Table 619) The reaction layer and the
the reaction rate was un-of the exposure cnadnioni as a
bull Fig 639 reasonably high for a
k experiment 75-5 Iryneslad and Keaer two specimens to MSW fad carrier salt (c uranium) that was saturated with CrjTcj The exshyposure was for 504 hr at 700C These samples formed reaction layers but lost weight (Table 619) As shown in Fnj 660 both uatcinls formed reaction layers but in heat 470-835 (071 Ti 260 Nb) there to be less penetration of the rcactants aVng the | boundaries The standard Hastdoy N had regions where layers of grams dropped not during the exposure The number and depth of cracks in the sliessed portion of the samples were less for heal 470435 than for stanshydard Hastcloy N but both materials formed extensive intergranutar cracks
Since the samples packed in the various telurides reacted extensively several experiments were run Hi which the samples and the teluride were separated in
113
(a)
(b)
(c)
- r - raquo
(d)
0 25 MI FfcS7 SywiwuM fcmdasht tfmmmm IS-l wfcMl wmdash laquo y mdash lt iraquoraquofciraquo raquo w laquo r f p w raquo o r irtNilmi far I W H m 7 W C n i
NralltOAraquo5tfrlfcril4-Slttilt I TiM Ilwtf 47MJ5 llraquo7l-lt Ti lA SbKultkat MRi lA f r Hbt AlaquopoMwl lOOx
114
(c )
(laquo )
(f) raquo bull O O W f
0 2 S laquo raquo
fplusmn S Ipniawn tnm rxpummM 75-3 Packed m CrTe granules for 250 hr al 650 C and deformed lo fracture ai 25 f flaquoraquo Heal 405065 Msireaed thy hear 405065 Urevwd tei heat 474-534 (2091 Ti 00131 Lagt imlaquorclaquoed (ltraquo heal 474-534 tlrcuedfrgt hear 474-535 (2131 TiOOH La 0031 Claquolunlaquoreslaquodlt1 heal 474-SJS laquorevd Atpnnshed lOOx
115
3ampF
bull 025am bull
the reaction capsule In experiment 75-6 standard Hasteuoy N was reacted with the vapor above CrTe 4 at 7000 for 1000 hr The spedmen pined a amount of weight (Table 619) did not form a reaction layer (Fig 6J6I ) but did form extensile inter-granular cracks (Fig 6 J 6 I Table 619) Experiment 75-7 was run in the same way but Cr 2Te was used The sample tost weight formed a surface reaction prodshyuct and formed mtergranutar cracks when strained (Table 619 Hg 662) In experiment 75-8 the source of tellurium was two nickel leRuriJes fc and 7 i The specimen lost weight did not forn a TJIMC surface reaction producl and did form rnieigranubr cracks (Table 619 Fig 6J63)L From these experiments it was concluded that the tellurium activity produced by Ct Te 4 was likely that best suited for screening studies
ExpeiHMnt 75-9 included 25 aloys which were exposed to tellurium vapor at 7000 for 250 hr The weight changes covered a range of +84 to 74 mg with no obvious correlation between weight change and crack depth or number (Table 619) These specimens were sealed in four different capsules for exposure to tellurium and there were differences in the extent of discoloration of the samples These differences are likely associated with slight differences in the extent of reaction due to variation of the temperature of the tellurium metal in the various capsules Thus it is quesshytionable raquo to how far one should carry the analysis of the data from this experiment
Owe further problem coacernmg data analysis which applies equaly w d to afl data sets is the baas that should be used for comparison The number of cracks ami their average depth are two very important paramshyeters However it is possible that a Tprrimrn cm have a large number of shaaow cracks ( e ^ beat 63 Table 619) or a few rather deep cracks (eg heat 62 Table 619) The formation of intergranuiar craci of any depth is important because this may indicate a tenshydency for embrittlement The depth of the cracks ts important because this is a measure of the rale of peneshytration of tefurium along the grain boundaries Howshyever for a relatively short test time (test 75-9 (2S0 hr)) the formation of numerous shalow cracks may be indicative of a near-surface reaction which wil not lead to rapid penetration with time Obviously longer-term tests are needed to determine the rate of penetration of tellurium into the metal
On the basis of number of cracks formed the alloys in experiment 75-9 which formed lew than 40 cracks per centimeter were 345470-835421543 237469-714 470-786 62 295 and 348 The alloys forming cracks with an average depth of lt 127 u were 63 469-714 295 348 469-344 421543 and 470-835 Several of the alloys appear good on the basis of both criteria These alloys all cont in niobium and several contain niobium and titanium Another parameter used for comparison was the product of the number of cracks and the average crack depth The alloys from expert-
l i t
( bull )
laquo
ltlaquov
(c)
lt)
I 0 2 9 raquo raquo gt Figt iuM Senates from uteiiaini 75-5 Sanpln exposed to feci all sraraKd laquo-iih Cr Tc for 504 hr ai 700C and strained
lo fraclarc al 25T ltraquo Standard HasteHor N bullntlrencd shoaMer (Agt standard HasteHoy N stressed p(c length sfoning region where grains were urn dnrine tall cipotnre (lt-gt heal 4704135 10717 Ti 260 Nb) oatlrroed thoakitr ltltgt heal 47f 4J5 stressed portion Aspotahcd I00X
117
(a)
(b)
l f l laquo Q l n - | I 0 2 9 M I
Flaquofcl TtiMwi lUmBij X ( h w O W I I w lono br mi earned to fjUarc ut F4pr of MM icwd pvnna iraquo lt
1154k ampMOftrtrfKMe4 lo the of tiinaei porno As pufcihfi
CrTlaquo j i7laquorCfof IflOx
ment 75-9 are ranked on this basis (Table 6J0gt Stan-dard Hasidoy N raquo significantly different from al other heats on this basis There are latfe variations among the other heats but it is difficult to pick out general trends on the basis of niobium and titanium concent rations
Several typical photomicrographs of samples from experiment 75-9 are shown in Fig 664 No reaction films were visible on any of these specimens The picshytures show dearly the wide range of cracking experishyenced by the various heats
The mechanical property data show small but signifishycant variations in the yield and ultimate tensile stresses of the various heals (Table 619) The higher stresses are grnerolly associated with the alloys containing the higher amounts of niobium and titanium However the
high fracture strain and reduction in area for a l h-ais indicate that only very small (if any) amounts of gamma prime formed during the 250 hr at 700degC
In experiment 75-10 steps were taken to ensure that the specimens were at a uniform 700degC and that the tdurium was at 300degC The weight changes were very erratic and show no correlation with the number of cracks or the depth of crack formation (Table 619) A sample of heat 425 was included in each of the two capsules used in tins experiment to obtain some idea of reproducibility The reprodudbflity was reasonably good Samples o alloys 405065 298 295 348 and 345 were included in experiments 7 5 4 and 75-10 Heats 405065 298 and 345 in experiment 75-9 cracked more severely than in experiment 75-10 Alloy
l i t
V - t
(b)
I AW hr art in
021 uigtiiiwil75-7 iioafAtlaquo4acor A
Cr f e j i ltKraquo lt t t HMta
laquo bull - - Craquofc
ltW SS^j-^n-raquobull
WMMMCS at ItXfC foe IWO hr aa laquo u m lt lo f IflOx
0 2 9 laquoMi itmtm 7W San phi r^puraquorf to Ike
to) Mat of mmiiwmtd porta raquogt claquogt laquo tf bull gt mcfcd
puftimi A ^riuhfd
IN
ITS
note bull bull laquo tat tract tdncti0c4 I cy
roat i
H m i oaccatraaoa t 0
( - -
I cy
roat i
H m Ti Nb (Mm
5laquon 4ltI5laquoraquo5 371 3lraquo 0 3 5 027 Si 3195 474-534 2 4 9 01013 U 27 JO 471-114 175 247 303 049 OM 2400 3ttS OM 13 2249 29S 20 217 3 2-5 2 1 29 024 0 3 7 1993 347 raquoM 0 4 7 Si 1924 4S14M 092 195 I9 IO 474-5J5 213 0 4 4 L raquo raquo pound r IBSI M U M P27 15 C i 1453 I I I 050 l-SS 1304 344 04laquo 049 1292 49-344 077 17 9 9 345 045 ft22Si 4 M 237 1J03 409 49-714 0S0 tJampO 352 2 1 9 raquolaquo 4 7 M 3 5 071 IM 290 421543 07 179 4707S 082 0 4 2 101 295 0 M 3raquo 34S 062 047 Si
Set TjNe 1H lw drbiM cheiwcJ jiulvcs
348 was less severely cracked in experiment 75-10 and Nat 295 reacted similariy in both tests Such differshyences emphasize the importance of duplicating test results before making important conclusions
The alloys in experiment 75-10 that formed lt32 crackscm were 413 34 295 4 1 1 421543 and 345 Those with average crack depths s 109 p were 421543 295413 345 and 298 Again this ranking is of quesshytionable value because alloy 298 had the shallowest cracks of the 12 specimens but formed a large number of cracks In an effort to combine the factors of number and depth of cracks the two factors were multiplied and the alloys ranked as shown in Table 621 There is a very large step between alloys 425 and 298 and the better alloys appear to be ones containing from 045 to 20 Nb with titanium additions of 1 ^ or less
The tensile data show small variations but do not show evidence of embriitiemeni due to gamma prime formation during 250 hr at 700degC (Table 619) In specshyimens from experiment 75-10 the wide range of trackshying behavior is apparent (Figs 665 and 666)
These tests have shown that several methods are availshyable for exposing metal specimens to tellurium The metal tefluride Cr Te 4 has an activity most consistent with our estimates of tellurium activity in an MSBR Specimens can be exposed to salt containing CrjTe 4 or exposed to vapor above the compound Tellurium metal at about 300degC has a vapor pressure of about I X 10 4
torr and appears IO provide a tellurium activity comshyparable to that expected in an actual MSBR The specishymens exposed thus far show that niobium is effective in reducing the extent of iniergranuiar embrittlemenl of Hastelloy N
615 EXAMINATION OF TeCen-l
B McNabb H E McCoy
The TeGen series of capsules was designed for studyshying the effects of tellurium and other fission products on metals The fuel capsule is a Vi-in-OD X 0035-in-wall X 4-in-long tube segment of the metal under
120
( c )
I OOIOf - _ I I J 0 2 9 M I
Fagtfcj64- CumdashjMiiun of imdashapamdashtm cmfcif bull l l i jNluj H lyye aBoyraquolaquoaoraquod wgt partial aitmdash11 erf tdNrimdash of 10 vm fat 250 br at 7WTC aad iliaan lo fraroarc at 2SC ltlaquoraquo Standard Hasfcttoy N that 4O5065i (142 crjckwrn a depth 416 raquoraquo IM modified Hastcfloy N containinc 08S^ Nb (aNoy 295) (10 crackson a depth 101 raquogt laquorgt modified Hastdloy N conlaaunK 082^ Ti 0427 Nb (alloy 470-786) (13 crackscm a depth 86 it 00x
Table 6 J I Rmdashfciwiof materials from expuimoH 75-10
Product of number of cracks and average epth
rnns) Alloy
number Concentration CJI
cracks 1 x rntci cm
epth
rnns) Alloy
number Ti Nb Other cracks 1 x rntci cm
4512 424 18 134 3245 421 219 104 3198 425 198 048 2328 405165 2157 425 198 048
713 298 20 336 413 10 113 209 348 062 047 Si 133 411 115 106 295 085 76 421543 07 45 345 045 022 Si
See Table 618 r detailed chemical aiulyicv
121
ltd)
( f )
I 0 2 5 M B I
Ff 65 Miami tpwmriw from expuwww 75-10 SpccmKru were cxrvwrd f-r 5n hr ji nn lt- ilt ihr apltlaquor iNiw irlluintm meiil JI nit C bullgt All- 424 iM jllgtgt i i rIjHn 45 II allot 4050 in allm 45 (gt alloy ^gtraquo A pohthrd Wfr
122
-1MS7t
(f) laquo0fllQH -
025 mm Fig 666 Stimti specimen from experiment 75-10expoatd tot 250 hraf 700Cfo fherapor above idmriwn meM it 300degC
(j) Alloy 413 (ft) alloy 348 ic)alloy 411 Irfraquo alloy 295 (ltbull) alloy 421543 if) all 345 A polithed IOOx
123
study The capsule is partially tilled with the MSRE-type fuel salt and irradiated in the ORR to produce fission products
The first experiment of this series involved fuel pins made of Inconei 601 standard Hastelloy N and type 304 stainless steel and the irradiation time was such that the amount of tellurium produced per unit area of metal in contact with salt was equal to that at the end of operation of the MSRE Some of the details of the postirradiation examination were described preshyviously2 2 A typical fuel pin is shown schematically in Fig 667 The segments marked A w re subjected to tensile tests using the fixture shown a Fig 668 The mechanical property data obtained roai the rings and the results of limited irtetallograpic examination were reported previously2 z More detailed mctallographic studies have been completed during this report period The segments marked B were used for chemical studies The salt from each segment was analyzed and the fission product distributions on the tube surface and a short distance into the tube were determined from two successive leach solutions The first leach used a verbodt solution (sodium vtrsenate boric acid and sodium citrate) which should have dissolved only residshyual salt from the metal surface The second solution was aqua regia and the time was sufficient to remove about
11 B McNlaquohb and II I McCoy IfSR Pnrmm Sununnu Pnifr Rip Feh gt tv~ ORM-5ltMpp 12 6
I mil ot the tube Both solutions were subjected to various chemical procedures to analyze for various nuclides and elements These results are partially anashylyzed and the results for tellurium will be discussed The tube segments marked ~C were retained for posshysible future studies
61 SI Metafognpaic Observations
Photomicrographs ot the three materials in the un-deformed condition are shown in Fig 669 Numerous voids were present near the surface of the Incopel 601 specimen to a depth of about 02 mil Voids were likely caused by the removal ot chromium from the alloy via reaction with U F 4 in the salt The Hasldloy S vrction shows no evidence oi chemical reaction with the salt The type 304 stainless steel shows some grain boundary attack to a depth of about 0_5 mil This was likely caused by selective removal of chromium along the grain boundaries The features in the type 304 stainless steel appear much like shallow cracVs and may have influenced the number of cracks that were observed in stressed samples of this material
Composite photomicrographs of the Inconei 601 rings after straining to failure are shown in Fig 670 Rings 2 and 4 from near the salt-vapor interface exhibit some evidence igt( attack but the other samples are almost entirely free of indications of chemical reaction
Photomicrographs of the deformed rings from the Hastelloy N capsule are shown in Fig 671 The count
olaquoM-oac n-ot
TTPt DESCRIPTION M O USE
bull VW bullbull IMG FOR HCCMAWCAL PROPERTIES
B fOU L E A C N (2 STEP
C StCTiQM TO K RETAINED
mdash EH0CAR
mdash A - i
4 -2 A-3 AN0 SALT LEVEL
z~ -laquo A-5
- S A-4 A - mdash C
mdash A - a A - raquo
mdash A- IO
mdash C
mdash A - M mdash A-12
mdash C
mdash A-13 mdash A-14 mdash A-15 mdash 8 mdash A - W mdash EMC CAP
f 667 Schematic docram of individMl feci pm jhowing the locaftoMof tat specimen
124
metaliographic sample indoles the fracture and an adjacent segment Since the fracture occurred at difshyferent locations the metallographic specimen contains varying amounts of inhomagcneously deformed mateshyrial For example Fig 67 I f includes a very small segshyment of homogenously deformed material whereas Fig 6 71 includes a relatively long segment As shown by the photomicrographs in Fig 671 and the data in Table 612 specimens from the vapor region (2-A-I) the salt-vapor interface (2-A-2) and rite bottom of the salt (2-A-l6) cracked most severely Three samples from other locations formed shallower cracks It is not known whether these differences are significant
Typical photomicrographs of deformed rings from the type 304 stainless steel capsule are shown in Fig 672 These specimens located on the inside surface had shalshylow cracks with an average depth of about 04 mil (Table 622) These cracks were rather uniformly distrishybuted in the samples from all four locations As noted in Fig 669 the unstressed specimen also contained cracklike features having a maximum depth of about 05 mil Hence the cracks in the stressed specimens may simply be the result of furti opening of features that are likely related to corrosion
6152 ClKiMcal Analyses for TeBormm
The lube segments designated B-l B-2 and B-3 in Fig 667 were subjected to several types of chemical analyses but only the results for tellurium have been analyzed in sufficient detail to report at this time The results for the three pins are shown in Tabic 623 The
Ffc668
0 Fixlare for ft leatinj rinji
of crack frequency shown in Table 622 was made in an effort to detect significant differences in cracking among the various specimens These counts are subject to numerous problems the main one being the inhomo-geneous distribution of strain within the sample In deforming the ring specimens in ihe fixture shown in Fig 668 the small portions of the ring located between the two parts of the fixture likely deformed very unishyformly but this length is very short relative to the total length The part of the ring that contacted the fixture likely deformed in some areas but was restrained in other areas by surface friction from the fixture The
Taate 6 J2 Smmmmy of crack frequency aad depth inToflMtiM for riant from TcGea-1
facts alaquo W M M t ID ratae at 25deg C
from TlaquoGCM fad Specimen nu iber
Crack frequency
(crack sin)
Crack depth (mils)
Average Maximum
2-A-l 480 080 20 2-A-2 450 II 22 2-A-4 410 060 12 2-A-5 480 058 12 2-A-8 MO 046 10 2-A-l 6 380 14 25
Type 304 (taMeu tted
1-A-2 160 04 12 3-A-4 310 042 10 3-A-8 260 036 10 3-A-I6 202 037 10
125
(a)
-J
(b)
(c) 20 40
- L - 1 _ 0001
60 MICRONS lt00 mdash SOOX -
laquo20 40
INCHES COOS
Fjj 669 Undeformed rings (ample No 9) from each TeGen fad pin near the middle of the fael aalL (a) Inconel 601 (ft) HuMelloy N(r) type 104 ttainlets jteel A polished 500x
600 inn
Ffc 670 Sample from Incond 601 fad put from TeGcit-l Kir failure al 25deg0 Portion of specimen exposed to fuel salt is on the I location A A (laquo) location A-5fr) location A-8 () location A-16
BLANK PAGE
Sch figure
j J u i u m l i i -Mi iWWLltLiWHt
126
a ten from (he location shown in Figr 667 and deformed to tide of cacti figure it Location A - l tftgt location A-2 ( r )
J
127
I Fig 671 Samples from Hwribr N fuel pin from TcGcn-l I bMurr M 25 ( Portim of specimen epltlaquoeraquol ilt fuel sill ii on l l location A-4laquo) lotjlion A-5 ltr) loolion A- i ft loci lion A-16
- l i bull gt i i glaquo i^_ a ^ bdquo ^ ^
ten from (he Uttattnas lthlaquown in I ijt A fc7 jlaquod deformed lltgt tide of ejch figure fat Location -1h) location A-2raquorgt
^
I
I t - -
BLANK PAGE amp bull
^bull
raquo-raquoMlaquoraquoWr
F)B 472 Sanata tmm lyat 301 itiialf steel fad pin ham Te atfunwed lo (xtmn at 25 C Poriwtt of specimen exposed lo fuel I locatio 4A to location AAIlt) location I6A
~^raquo-raquo i i T -- T-II bullraquoMraquoraquoMr5w mi j immmtmt^m
mm - bull - - bull bull bull - bull -
BLANK PAGE
mdash t - bull bull-bullbull -r^gatMtJliHwJraquoiWrraquovraquotj^WVu^-4-tgt- ~J(W~
fiMAmimraquom0mfMraquo-mdash- --- bullmdashmdash~~^--raquo bull
128
600 iim
M type 904 minim Heel fad pin from TlaquoClaquoM-I Rings taken from the locations shown in Fig 667 and C Portion of specimen exposed to fuel salt is on the lower side of each figure ltn Location 2A Ih) (lt) location I6A
2 ^ - m TMinfc
BLANK PAGE
128
600 pm
Ac locations shown in Fraquo 667 and bullf each fifiire It) Location 1A (ft) 3 L +ot nMtmgwmm
129
rlaquoJ3 raquo T e i bull Tea
nmHtrntMiaoam location
Type Concentration of bull T e C o ~ e ~ r t - o f bull bull T e nmHtrntMiaoam location
Type
bullpm total at JpnWg gcnr at i f f bull p a i o t a l o t a p a V l an or i a f
No 1 - IncondtOI 11 111
A B
S 2 J X 1 0 4tS X 10
4 2J7X 10
poundraquoSx 10 237 x 10
4 444 X 10
IB2 IB2 IB2
A B C
lt2J x 10 159 x 19 7laquoS X 10
4 r7SX 10 114 X 10
lt2J7 x 10 bull00 X 10 744 X 10
4 113 x 10- 45 x 10
IB3 IB3 IB3
A B C
pound53 x 10 27 X 10 247 x 10
4 345 X Iff 331 X 1 0
lt l 7x 10 34 X 10 143 X 10
4 57 X 10 99 x 10
No 2 - HasteHoy N 2raquo1 211
A B
lt M ( 10 749 X 10
4 3-Mx 10bull
lt I 4 4 X 10 497 X 10
4 094 X 10
2B2 2B2 2B2
A B C
raquoj x 10 29S X 10 7t X 10
4 Ml x 10 bull 5 i x 10
lt5 4x 10 202 X 10 594 X 10
4 3-7 X 10 24 x 10
2B3 13 2B3
A B C
lt54 X 10 laquol9x 10 34SX 10
4 422 x 10 bull 249 X 10 bull
lt 5 4 x 10 bull 05 X 10 393 X 10
4 U l x 10 141 x 10-
No 3 type 30 stainless start
3BI 3BI
A B
552 X 10 131 X 10
304 X 10 072 x 10bull
959 x 10 143 X 10
IS0X 10 3-44 x 10
3B2 3B2 3B2
A B C
954 X 10 25copy x 10 900 x 10
bull29 X 10
131 x 10
30 x 10 340 x 10
1042 x 10
bull J l x W iat x io 4laquoX 10
3B3 3B3 3B3
A B C
I M x 10 127 X 10 S3S x 10
116 x Icopy 044 x 10 74 X 10 bull
542 X 10 315 x 10 323 x 10
3-3 X 10 19 X 10bull 197 X 10
A denotes 100 a n aarntwn obuiotd by leaching the metal nanjlr m mbocit (soJimdash Tersenate boric an mdash I iiiinmdash cttnlel B i 100 cm sowlion obtained by l u i l raquo n the metal amftt m raquoraquobullraquo reeja lo remore aboat I M i of nartaLC denotes 100 cm sotation obtained by distorting aboal I g of salt in Mtric icid ( I JO saturated with bone acid Counts for iniiiidojl Radioes gram in dionfegralions pei Minnie (dpntt total for chemistry types A and Band dpM per graa of salt for type C daroMBry saMpfc These cooam ace laboratory w n t u i and abject to sctta corrections omkh lane not been none cThese concentrations are espitjatd as grams of the particnlar nncMr per CM of Metal sartace for cheaaatry ample types A an B ant ar exams of nailidc per gram of alt for chemistry siMpli type C The nines hare been court nd back to the conrfcjsiBn of die H amnion Concentration flwinglit safTiciently low to be ignore
sample numbers ending with I (ie I B l 2B1 and 3BI ) designate the material that came from the fuel pin wall exposed to the gas space above the salt The ample numbers ending with 2 designate material that came from the fuel pin exposed to the fuel salt just below the sail-gas interface and the sample numbers ending with 3 designate material that came from the portion of the fuel pin exposed to fuel salt near the bottom of the capsule Solutions were prepared for analysis by leachshying metal samples of each tube in verbocit to remove residual salt (type A solution in Table 623) leaching the rings in aqua regia (type B solution in Table 623) and dissolving about I g of salt removed from the metal rings in nitric acid (type C solution in Table 623) These solutions were counted to determine the amounts of J 7 T c and T e present The direct results of
these analyses are presented in Table 623 but cannot be interpreted directly because a number of corrections have not been made The data have been corrected as well as possible o reflect the concentration of each nuclide at the end of irradiation The concentrations for the leaches from the metal specimens are expressed as grams per square centinpoundtcr of tube wall exposed to the fuel salt and the concentrations for the salt samples are expressed as grams per gram of salt
The ORIGEN code was used by Kerr and Allen to predict the concentrations of tellurium isotopes that should have been present These calculations have been used extensively in the subsequent analysis of the data Table 624 compares the quantities of 7 raquo T e and l l laquo m T e f o o n ( j m | h e ( n r e e f ^ i p j p W j ( n thoje p r e
dieted to be present by the ORIGEN calculations For
130
each fud pin the one sample taken of the tube in the gas space was assumed to be typical of that region and the two samples from the salt-cowered parts were avershyaged to obtain a typical value for the salt-covered region As shown in Table 6 2 4 generally about 20 of the T T e and 1 T e was found The percent of tellurium found in the Incond 601 capsule was apprecishyably higher due to the higher amount found on the salt-covered metal surfaces
There are several possible ex|)lanations why the conshycentrations of I 7 T e and 2 T e found are only about 20 of those produced One possibility is that the amounts calculated arc too high This appears not to be the case but the calculations wiQ be checked further The most likely explanation is that the add leach was not sufficient to remove all of the tellurium from the wall The tube segments were suspended in the acid with the made and outside surfaces of the tube wall exposed as well as the cut surfacr on each side of the ampin tube segment Based on the weight changes obshyserved and the assumption of uniform metal removal the thickness of metal removed appears to be about 08 mil Since the cracks extended deeper than 08 mil in the HasteDoy N the tellurium likely penetrated deeper than did the leaching solution However the cracks in the other two materials were very shallow and the
08-roii dissolution should have recovered a higher fracshytion of the teflurium if one can equate the depth of cracking to the depth of tellurium penetration The results in Table 6 2 4 show no evidence of a systematic variation in the percent recovered from the three tubes Several possible explanations for the apparent discrepshyancy in the quantities of teflurium generated and that actually found are being investigated but none appears reasonable at this time
The concentrations of 2 7 T e and 2Te found in the salt can be used to predict upper limits for the solubility of tellurium in fuel salt under these condishytions The I 7 Te nuclide concentration in the a l t ranges from 114 X 10 to 131 X 10 g pet gram of salt (Table 623) The ORIGEN calculations were used to estimate the ratio of l 2 T Te to total tellurium and this ratio was used to convert the above concentrations of T T e to total teflurium concentrations of 007 to 083 pom Smiariy the concentration of 2 T e ranged from 45 X 10 to 648 X 10~ g per gram of salt and these correspond to total teluriurn concentrashytions of OJOS to 113 ppm The low values in both cases were noted in the Inconel 601 pin and the higher values were observed in the type 304 stamhts steel pin The concentrations m the HasteSoy N pin were only slightly less than noted for the type 304 stainless steel pin The
TaMt624 A w o mdash l o f T CnhnsM bull n r i o t i kKSfuOtv ol fed pint tmm TcGea-I (a)
IncondoOl HastdloyN Type 304
mje bull T bull gtraquorT e T e mje bull T bull gtraquorT e T e bull T e bull T e
Salt 41 x 10 bull 13 x 10 - 10 x 10- 35 x 10 M X 10 74 x 10 Metal-vapor space 14 x 10 24 x 0 21 X 10 50 x 10 2Jgt X 10 i2 x ie- Metal-sll covet at 17 x 10 23 x I t r 78 x 1 0 25 x 1 3 44 X iW 39 x 10 T
Total fomd 19 X ltgt-bull 27 x IC II x 10-bull 3 5 x 10 laquo 2 x 10 23 X 10 Total formed 3 A 2 x 10 bull 134 x I 0 f 40 x 10 148 x 10 36 X 1 0 134 x 10 laquo ferccM found $2 20 2raquo 23 23 17
of frnl MM hum TlaquoGcn-l (10 aon)
Location Incoiwi bull 1 HastcftorN Type 304
is sled Location bull T e raquo T laquo T e bull T e
Type
bull T e raquo T laquo T e bull T e T e T
Mctal-vapor space Bl MetaMaii location B2 Metal-salt locaiion 83 Avenge if foul yield evenrr distributed
257 bull 75 345
112
446 113 576
413
3J6 152 422
123
94 376
IS 1 456
376 229 095
112
214 I M 103
413
131
higher chromium concentration of the Inconet 60 may have caiced the lower tellurium concentration in the fuel salt
The con-entrations of l l l m J e and t 2 9 m l e are expressed in Table 625 in terms of grams per unit surshyface area There appear to be significant variations within each capsule but there is no consistency beshytween the various pins The high value for ITe in the vapor space of the type 304 stainless steel pin is likely anomalous since the n T e t$ not i s high Thus ai this time we conclude that the tellurium is distributed uniformly over the entire surface area of the pin
616 SALT PREPARATION AND FUEL PIN FILLING FOR TeGea-2 AND -3
M R Bennett A D Kelmers
The purpose of this portion of the TeGen activity is to prepare purified MSRE-type fuel salt containing bulliiV and to then transfer a known quantity of this salt into fuel pins gtr subsequent irradiation in the ORR One batch of purified salt will be prepared and used in two filling operations to fill two sets of six fuel pins each identified as TeGen-2 and TeGen-3 Similar activishyties in 1972 to fill the fuel pins used in experiment TeGen-I have been previously described2 3 To MSRE-
type fuei carrier salt containing LiF-BeF-ZrF4
(647-301-52 moleltv)sufficient U O j and 2 U F 4
were added to produce a fmji composition of LiF-BeF -Z r F 4 - I 3 3 U F 4 - 2 U F 4 63J08-29J5-5 O7-1 0O-15O mole ) after hydefluorination to reduce the oxide content The uranium will be reduced by hydrogen or bv beryllium if necessary to a U3 content of 10 to 18 and a measured xlume of salt will be transferred into the fuel pins The design permits obtaining a preshydetermined volume in the pins by flushing through an excess salt volume and then blowing back the salt in the upper portion of the pins to leave a predetermined volshyume
The equipment in Building 4508 used previously for this work was reactivated and modified where approprishyate A safety summary and step-by-step operating proceshydure have been prepared and approved During the latshyter part of this i port period the salt components were charged to the salt purification vessel and a 364ir hydrofluorination at 600degC was completed Both filshytered and unfiltered samples were obtained after hydroshyfluorination in copper filter sticks After analytical results indicating satisfactory removal of oxide liave been received hydrogen reduction of about 1 of the UF 4 will be carried out
23 R L Sain J H Suffer H E McCoy and P N HjabcnrcKh MSR htrprnm Srmmcvni trofr Rep Aug il 1972 ORNL-4832 pp 90 9
7 Fuel Processing Materials Development
J R DiStefano H E McCoy
The processes that are being developed for isolation of protactinium and removal of fission products from molten-salt breeder reactors require materials that are corrosion restrtint to bismuth-lithium ind inoiiev fluoshyride solutions Past experience has indicated that alshythough their solubiities in bismuth are low iron-base alloys mass transfer rapidly in bismuth at 500 to 700 SC The most promising materials for salt processing are molybdenum Ta-10^ W and graphite Molybdenum has been tested in a wide range of bismuth-lithium solushytions for up to lOjOOO hr and has shown excellent comshypatibility Thermodynamic data and literature reports indicate that molybdenum will also be compatible with molten fluoride mixtures
Ta-10 W also has excellent compatibility with bismuth-lithium solutions but tests are required to measure its compatibuity with molten fluoride salts A thermal convection loop has been constructed of Ta-10 W and a test with LiFBeF2-ThF4-UFlaquo (72-16-117-03 mole ) wffl be started during the next reporting period
Graphite has shown excellent compatibility with both bismuth-lithium solutions and molten salts Although no cheruicai interaction between bismuth-lifcisas solushytions and graphite has been found the hqtsd-KjsuS solushytion tends to penetrate the optn porosity of graphite Recent tests have evaluated the extent of penetration as a function of structure of the graphite and the Uthium concentration of the bismuth-hthium solution Dynamic tests of graphite with bomuth-tithium have thus far been limited to quartz oop tests circulating K - 0 J 0 I wt ( 0 3 at ) Li During the report period a test was
completed in which graphite samples were exposed to Bi-24 w 1 (42 at vt) Li in a molybdenum thermal convection loop for 3000 hr at 600 to 700degC
71 STATIC CAPSULE TESTS OF CRAPHTTE WITH BISMUTH AND
MSMUTH4JTHIIJMSOIIJ110NS
J R DiStefano
Samples of graphite with varying densities and pore diameters were exposed to H-017 wt (48 at ) Li and K - 3 w t (48 at ) Li in capsule tests for 3000 hr at 650degC Two of the graphites (Table 71) were pitch impregnated t j increase their densities and reduce their pore sizes1 The relatively high densities of these graphshyites indicate that impregnation was effective but the pore size distribution in the samples shows that some of the larger pores were unfilled or only partially fdkd Specimens were graphite rods 6 mm (024 in) X 381 mm (15 in) long that were threaded into an ATJ graphite holder The specimens and holder fit into a graphite capsule which contained the bismuth-lithium solution (Fig 7IK The laquoniire aoembiy was sealed in a suhwVss steel outer capsule by welding in argon Samshyples exposed to 61-017 wt (48 at ) Li showed little evidence of penetration except in low-density areas (Fig 12) Samples exposed to Bi-3 wt (48 at ) Li were penetrated more uniformly and the depth
1 Al grapfcilei were fabricated by C ft Kennedy of the Carbon and Graphite Groap Merab and Ceramics Dmnon OftNL
TaMr7l P f t trjtnPnt 01 yinpfcitt fcy lNpMvtfc4ilfcM McapfritttattlbrJtei b r a t t s r c
MISflMM
Graphite demtty Igcml
Ranee of porediam
Maximmn pore diameter chat
conrribnies 10 to total pDtoaly
ltraquogt
nuefration (mils) bulldentiOcatiow
demtty Igcml
Ranee of porediam
Maximmn pore diameter chat
conrribnies 10 to total pDtoaly
ltraquogt K 0ITOU m 3Li
334K 44-25 K 33-3SK 44-26K 44-23K
IM IM 190 ISO 159
01 1 01 2 01 2 01 35 OI 4 5
1 12 I J I J 45
0 5 0 17 8 0 5 5 0 -2 8 0 2 15
Impregnated
NonvMrform penetration in one -gtr two area only
132
133
0MlaquoL-0laquoCrS-l4M9
Flaquo 71 GapMe (bimdasheh lithww) opiate fed asmMy
of penetration increased with increasing pore size and decreasing density Results from previous tests have been inconclusive as to tnr effect of lithium concentrashytion in bismuth on penetration of graphite In the curshyrent series all graphites were penetrated tc a greater extent by K - 3 wt (48 at ) Li than by Bimdash017 wt 9f (48 at ) Li Tests of 10000 hr duration with these graphites are continuing
72 THERMAL GRADIENT MASS TRANSFER TEST OF GRAPHITE IN A MOLYBDENUM LOOP
J R DiSuiano
Although graphite has low solubility in pure bismuth (less than I ppm at 600degC) capsule lest results have shown that higher carbon concentrations are present in Bi -2 wt (38 at ) Li and K-3 wt (48 at ) Li solutions after contact with graphite To avoid the joining proolems associated with fabrication of a graphshyite loop a molybdenum loop was constructed and interlocking tabular giaphite specimens were suspended
in the vertical hot- and cold-leg sections2 In addition to mass transfer of graphite from hot- to cold-leg areas penetration of graphite by bismuth-lithium and mass transfer between graphite and molybdenum were evalushyated
721 WcajMCkaafes
The loop (CPML4) circulated K-24 wt (4 at 3 ) Li for 3000 hr at 700degC (approximately) maximum temperature and 600degC minimum temperature Weight changes in the graphite samples are given in Tables 72 and 7 J After the bismuth-lithium solution was drained from the loop the samples were removed and weighed (after-test column in Tables 12 and 7 3 ) Subshysequently they were clltmdashned at room temperature in ethyi alcohol and in an hO-HNOj (100 ml H 2 O-30 ml 90 HNOj) solution to remove bismuth-lithium adhering to the surfaces of some samples Samples from the cold leg were weighed and then kept in air for two days prior to the alcohol treatment After soaking in alcohol these samples showed larger weight gains than the after-test weight gains and this is attributed to reacshytion of lithium in the sample with moisture in the air during the two-day period AD samples showed large weight gains (33-67) and gains in hot-leg samples were on the average larger than those in the cold-leg samples
122 Compositional Changes
Graphite samples were analyzed before and after treatment with H 2 0 - H N 0 3 and the results are shown in Table 74 These results indicate that bismuth was primarily responsible for the large weight increases and that samples picked up molybdenum but treating them with H 2 0-HNOj completely removed the molybshydenum An electron-beam microprobe analysis of a graphite sample before acid cleaning showed that molybdenum was present on the outer surface of the specimen (Fig 13) Chemical analyses of other graphite samples after acid cleaning are shown in Table 75
Analysts of bismuth-lithium samples from the loop are shown in Table 76 For sampling the hot leg was sectioned so that one sample came from the surface that was in contact with the molybdenum tube wall while the other sample was taken from the interior of the section away from the wall The concentration of carbon in the melt was highest in the sample from the hot leg and both molybdenum ami carbon concentra-
2 i R DiStefano MSR Program Semimnu frofr Rep Pth 28 1975 ORNL-5047pp 140 41
li-3 11 V-IMIOi
-I5H raquobull Mplaquolaquom
F| ) NtMlnltpnorpirMttuiriMwManorMnKluHurinfMltiiid Itlhlum InMwiulli tuniliiiltgtnraquo IIHNI hr M fcjnV
13S
r7J iraquoATJ bull CML4
Wclaquofci If) Welaquofci bullKVU9 I
n mdash t r i bullefore Mi l
After m i
After
bull U k n t w l
After
raquoH04mo
Welaquofci bullKVU9 I bullefore
Mi l After m i
After
bull U k n t w l
After
raquoH04mo ltlaquo) laquoltgt
5 0 4 5 3 0S244 0 1 2 2 0704 02443 54 7 05220 0970 0 95 0S29S 0 3071 59 04494 09551 0933 0X298 OJ304 6
| l gt 0 400 0959 0919 07944 03144 I I 0432 0 3 3 9 0S3O3 07102 0277 4 12 0 4 5 09302 0923 079 03075 7 13 04753 0979 0974 0 7 02933 2 1 0432 09175 09152 075 0302 5 17 04742 09099 0905S 0794 02952 62 IS CS070 09005 0 J 9 5 07975 0290S 57 1 04709 0-raquollaquo9 0142 0 7 1 02459 52 zo 0539 091 M 09149 0 107 0 J 7 J 51 21 0513 OK52 0 J 2 9 072 02453 4 22 0 5 I M 0 M99 0 M59 0759 0J407 4 23 0-539 09103 090 07475 02067 3 24 03405 0 5 4 5 0 4 9 7 07235 01130 33
Top of IKM ley I
Kwlion of hoi leg M laquo | I J M I
rare 0 700C Q0-2OC
Vclaquofti it)
Wclaquoht After Wclaquoht
n m b r t Before After stjfldiHC in am tot two day
After
H 0 -HNO
mcreaK n m b r t
lev lejl
stjfldiHC in am tot two day
After
H 0 -HNO ltIgt I
makohol
27 04 4 0749 0722 0 4 0 01794 39 2 0421 0 2 4 OS4I2 0 2 0 01439 30 29 04717 07793 07913 06433 0 I 7 - 36 30 0477 0713 07239 0291 0151$ 32 31 044 07209 07315 0 3 9 a i 5 4 8 32 32 0427 0729 07744 0647 01 raquo20 3 33 047ft 07193 07 TOO 0331 01543 32 34 0470 0756 0772 0653 012 39 35 0424 073raquo2 0745 0 2 9 0 016 3 3 0423 0749 0759 0343 01520 32 37 0447 07331 07432 0 239 01572 34 3S 04713 07513 0719 0641 01705 3 39 04745 0749 070 0 506 0171 37 40 042 0725 07390 0233 01605 35 41 04725 0745laquo 07J53 0 419 01694 3 42 04100 07427 07525 0652 01726 36 4 3 0476 0720 07401 0647 01712 3
Top of onM leg lempmlvrc 60 60 C ftotlom of cold ley temperalarc 620 630C
136
aMr 74 n a m e d bull bull bull bull bull bull bull ttVli
S jmr t rm HRJIWT Coadiiion Cuacramnunlraquo i
S jmr t rm HRJIWT Coadiiion 3i Li gt
4 (hH WTraquo 4 tbraquort llaquogt
i Ui4d iclt
l a t k a a r d Acid cftcaAGd (bullctnacd Atid ckaacd
4 3 43 40
bull gt 0J I 04
bull11 ltlaquolOI
bullMM ltlaquoMU
tions were higher than were found previously in quart loop tests circuiting Bi-OjOl wt (03 n bulllt Li Quartz loop test 11 contained molybdenum samples and analysis of the bismuth-Uthium solution after test shewed that t contained 25 ppm molybdenum Quartz loop 8 contained samples of three different grades of graphite and the bismuth-tiimum solution contained 10 to 15 ppm carbon after the test
J O B Caiwt j ad L ft Trotter MSR i Awfr Rep Air _ 1971 OKSL-4 p i - 3
V1330SS
BACKSCATTERED ELECTRONS
- - - Oraquo J
V
8 i M a X-RAYS Me L X-RAYS
Ffcgt 7J EMCWIM kmn) laquoeaaninj M H J M r laquoapnlaquo taawnf to Mnmrth Vnw IA) a backmttcrcd electron picture of sample tarface dark material n tnpfcitc and bright material is bianulh and malybdemHM as indicated by iff)and O
117
Tank 7 3 C k a m anakwaaf p i j i i i r bull bull | l i r f c mdash C F M L - 4
bull bullbe U Mo
1 Hot kg 37 0J5 ltOJraquol ltraquo H o i k s 42 044 lt0OI
15 H o i k 4 04 ltO01 l raquo Hocks 3 0 J 5 lt 0 0 1 24 Hotks 2i 025 ltOOI ^ T C o M k f J 0 3 5 ltO0 I 31 C o M k f 21 0 2 5 lt00I 3 C o M k f I t 02 ltoot 42 CoMkc 23 02 lt0Jraquo
Sampio plusmni deaneu m H OMNO prior to a i r
Tabk7 A ^ s t t t a M M i
CoaceaiDiMt
Sample location C ippa l
Mo tppau
Li fit
Hot k f icowl Kof kg iflwfaotf r
CoM kg loner
43 10 24
17 102
4
23 3 0 1
On a raghl bam Interior tampk
Surface simple in contact raquonb molyb i fcmdash rabe laquoaH
Selected graphite samples from hot- and cold-leg regions are shown in fig 74 The white phase distribshyuted throughout the samples is bismuth these samples were add cleaned and it is evident that bismuth was dissolved from the area near the surface Molybdenum samples from hot- and cold-leg regions are shown in Fig 75 Surface layers measuring 0015 to OJ025 mm (0 6 -1 mil) thick were found on the hot-kg sample In some areas ttwie was a single layer while a double layer was found in other areas Electron-beam mkroprobe analysis indicated the single layer andor outer layer to be primarily molybdenum This layer was much harder than the base metal (1000-1200 DPH compared with about 200 DPH) indicating that it is probably MojC Where there is a double layer the outer layer appears to be MojC but the inner byer n primarily bismuth One explanation is that the MojC layer cracked andor spailed allowing the entry of bismuth which did not drain when (he lest was terminated The molybdenum sample from the cold leg also exhibited a surface layer
i o raquo f l u C mm t h k k i gt i i 33S SSSH3 S CCSSpSKBOS to that found in the hot leg Samplrs of molybdenum from hot and cold legs have been submitted for chemishycal analysis
The prindtMl objective of this experiment was toeval-uate temperaiure-gtadieai mass transfer of graphite in bismuth umijiuiug a retainer high concentration of lithium However mass transfer data were obscured by the gross pickup of bismuth by the graphite samples Previous capsule and quartz loop tests with ATJ graphshyite had indicated much less intrusion of the graphite by bismuth than occurred in the molybdenum loop test This suggests that the permeabihty at ATJ graphite to bisnush-hdnum does not depend simply on the po-rc^y of the graphite It is generally accepted that some fracioa of the pores in graphite is effectively sealed off 7uraquo contributes nothmg to flow Therefore the conshynected pore system controls the penneabraty The shape of the connected pores influences the type of flow and die length of the path the fluid takes through the sample For a nonwettiug liquid the external presshysure forcing the liquid into the pores 1 must overshycome the surface tension of the liquid This defines a critical pore radius r( and unt l the pressure exceeds the value given by
lrraquo=27costfr c ltgt
where y is the surface tension and 9 the wetting angle the pore cannot support flow Thus for a given - I f rc is the minimum pore size that w H be penetrated In both the metal and quartz thermal convectica loops IT is determined by the argon overpressure ( lt l atm) and the height of btsmmh-fcthium solution above the sample and these wne essentially the same in both types of tests Temperature affects both a and 9 but all o( the tests were operated under similar thne-temperature-^r conditions Graphite samples used hi the quartz too tests had almost four limes the surface area o f the tabushylar specimens used in the current test but they were almost three times as thick The larger surface area of the quartz loop specimens should have increased the relative amount of bismuth-lithium intrusion but the greater thickness of these samples would reduce the pershycentage increase ATJ graphite samples from the quartz loop tests increased in weight by 01 to 06 wt ar far less than the 30 to 67 wt increases noted hi samples from the current loop test Thus specimen geometry alone does not seem to explain the differences noted However the surface tension o and wetting angle 9 were
138
3
i 8
a
139
Y-I33405
- n r fimfir nriiiTii ifiari Bottom of Hot Leg 600C Bottom of Cold Log 620C
f 75 MolyMniBin tube waN from thermal comectkm loop CPML-4 thai cin slated Bi-24raquo Li and contahnd graphite ^CCMCHS
probably different because the lithium concentrations of the bismuth-lithium solutions were different and molybdenum was present in the current test It is posshysible that the presence of molybdenum on tie surface of the graphite had a marked effect on the contact angle 0 fn an earlier series of tests the bismuth content of graphite specimens was much higher when they were tested in molybdenum capsules instead of graphite capshy
sules4 Accordingly data on the wetting of graphite by-bismuth containing lithium and other constituents of processing solutions would be useful for predicting the resistance of graphite to penetration
4 J R PiStefano and O B CavmMSR Profnm Semumnu Pmgr Rep Feb 2K 1975 ORNL-SM7 pp 137 39
Pan 4 Fuel Processing for Molten-Salt Reactors
J R HightowerJr
The activities described in this section deal with the development of processes for the isolation of protacshytinium and for the removal of fission products from molten-salt breeder reactors Continuous removal of these materials is necessary for molten-salt reactors to operate as high-performance breeders During this report period engineering development progressed on continuous fluorinators for uranium removal the metal transfer process for rare-earth removal the fuel recon-stitution step and molten salt-bismuth contactors to be used in reductive extraction processes Work on chemistry of fluorination and fuel reconstitution was deferred to provide experienced personnel for the prepshyaration of salt for the TeGen-2 and -3 experiments (Sect 617)
The metal transfer experiment MTE-3B was started In this experiment all parts of the metal transfer process for rare-earth removal are demonstrated using salt flow rates which are about 1 of those required to process the fuel salt in a lOOO-MW(e) MSBR This experiment repeats a previous one (MTE-3) to determine the reasons for the unexpectedly low mass transfer coeffishycients seen in MTE-3 During this report period the salt and bismuth phases were transferred to the experishymental vessels and two runs with agitator speeds of 5 rps were made to measure the rate of transfer of neo-dymium from the fluoride salt to the Bi-Li stripper solushytion However in these runs the fluoride salt was enshytrained at low rates into the LiCl which resulted in depletion of the lithium from the Bi-Li solution in the stripper Fuel-salt entrainnient was unexpected since no entrainment was seeii in experiment MTE-3 under (as far as can be determined) identical conditions The Measurement of mass transfer coefficient in these first tvo runs was not compromised by the cntrainment The measured mass transfer coefficients were lower than
predicted by literature correlations but the values are comparable to those obtained from experiment MTE-3
Mechanically agitated nondispersing salt-metal conshytactors of the type used in experiment MTE-3B are of interest because entrainment of bismuth into the fuel salt can be minimized because very high ratios of bisshymuth flow rate to salt flow rate can be more easily handled than in column-type contactors and beczuse these contactors appear to be more easily fabricated from molybdenum and graphite components than are column-type contactors Attempts were made to measshyure entrainment rates of fluoride salt in bismuth and entrainment rates of bismuth in fluoride salt under conshyditions where the phases were not dispersed and under conditions where some phase dispersal was expected These measurements were made in the o-tn-diam (01 S-m) contactor installed in the Salt-Bismuth Flow-through Facility The results indicate that mild phase dispersal with in concomitant high mass transfer coeffishycients night be allowable in the reductive extraction processes We are continuing development of methods for measuring mass transfer coefficients in mercury-water systems to learn how to scale up contactors which would be used with salt and bismuth
A nonradioactive demonstration of frozen salt corshyrosion protection ir a continuous fluorinator requires a heat source that is not subject to attack by fluorine in the fluorinator To provide such a heat source for future fluorinator experiments we have continued our studies of autoresistance heating of molten salt During the report period we have completed new equipment for studying autoresistance heating of molten salt in a flow system similar to a planned continuous fluorinator exshyperiment three preliminary runs have been made with the equipment The design was started for a facility for developing continuous fluorinators and equipment is
140
141
being installed for an experiment to demonstrate the effectiveness of frozen salt for protection against fluoshyrine corrosion
The uranium removed from the fuel salt rraquogt fiuorina-tion must be returned to the processed salt in the fuel reconstitution step before the fuel salt is returned to the reactor An engineering experiment to demonstrate the fuel reconstitution step is being installed In this experishyment gold-lined equipment will be used to avoid introshyducing products of corrosion by U F and U F S Alternashytive methods for providing the gold lining include elecshytroplating and mechanical fabrication The choice beshytween the two depends on availability of gold from fcRDA precious-metal accounts and the price of gold from the open market Instrumentation for the analysis
of the vessel off-gas streams has been installed and is being calibrated
Future development of the fuel processing operations wdl require a large facility for engineering experiment A design report is being prepared to define the scope estimated design and construction costs method of accomplishment and schedules for a proposed MSBR Fuel Processing Engineering Center The building will provide space fcr preparation and purification at salt mixtures fcr engineering experimenis up 10 the scale required fcr a I0OO-MW(e) MSBR and for laboratories maintenance areas and offices The estimated cost of thrs facility is SISjOOOjQOO and authorization is proshyposed for FY 1978
R Engineering Development of Processing Operations
J R Miditower Jr
81 METAL TRANSFER PROCESS DEVELOPMENT
HC Savage
During this report period the salt and bismuth solushytions were charged to the process vessels of the metal transfer experiment MTE-3B Two experiments were completed in which the rate of removal of neodymium from molten-salt breeder reactor fuel salt (72-16-12 mole LiF-BeF 2-ThF 4) was measured
The MTE-3B process equipment (Fig 81) consisted of three interconnected vessels a 14-in-diam (036-m) fuel salt reservoir a 10-in-diam(025-m)salt-metal conshytactor and a 6-in-diam (015-m) rare-earth stripper The salt-metal contactor is divided into two compartshyments interconnected through two 05-in-high lt 13-mm)
I H C Savage Bngmeenng Development Studies for Molten-Sat Breeder Reactor Processing Xo -0 ORNL-TSM870 (in preparation)
by 3-in-wide (76-mm) slots in the bottom of the divider Bismuth containing thorium and lithium is cirshyculated through the dots Thus fluoride fuel salt was in contact with the Bi-Th in one compartment and LiG was in contact with the Bi-Th in the other compartshyment The stripper contains lithium-bismuth solution (5-95 at ) in contact with the LiCl Mechanical agitashytors having separate blades in each phase in the conshytactor and stripper were used to promote mass transfer across the three salt-metal interfaces The fluoride fuel salt was circulated between the reservoir and contactor by means of a gas-operated pump with bismuth check valves The LrCl was circulated between the stripper and contactor by alternately pressurizing and venting the stripper vessel
The bismuth-thorium phase was circulated between the two compartments of the contactor by the action of the agitators and no direct measurement of this flow rate was made during the experiment however measshyurements made in a mockup using a mercury-water system indicated that the Bi-Th circulation rate between
ORWL-06-71 1471
AWTATORS-
LEVEL ELECTRODES
LiT-raquoF--TMU Li-a
FLUORIDE SALT
RESERVOIR
SALT- KCTAL CONTACTOR
M M EARTH STRIPPER
F 81 Flow diagram for metal trmrfcr experiment MTC-3
142
143
the two compartments should be high enough to keep the concentration of rare earths in both compartments essentially the same2 This was found to be the case in the two experiments in MTE-3B
In this experiment neodymium is extracted from the fuel carrier salt into the thorium-bismuth solution Next the neodymivm is extracted from the thorium-bismuth into molten LiCI and finally (he neodymium is stripped from the LiCI into bismuth-lithium alloy
Operating variables in the experiment are
1 the flow rate of the fluoride fuel salt between the fuel salt reservoir and the contactor
2 the flow rate of the lithium chloride salt between the contactor and the stripper vessel
3 the degree of agitation of the salt and bismuth pluses in the contactor and stripper
4 the amount of reductant (lithium) in the bismuth phase in the contactor
The operating temperature of the systen is ^-650degC Overall mass transfer rates for representative rare-earth fission products are determined by adding the rare earth to the fluoride fuel salt in the reservoir and observing the rate of transfer of the rare earth across the three salt-bismuth interfaces as a function of time by periodic sampling of all phases
2 H O Weeren and L E McNcese Engineering Developshyment Studies far Molten-Sail Breeder Reactor Processing So 10 ORNL-TM-3352 (September 1974) pp 57 59
[taring the course cf the experiments the concentrashytions of neodymium in each phase were deteiiaiacd by counting the 053-MeV gamma radiation emitted bv 4 T N d tracer added to the neodymium origmaBy in the fuel salt This provided a rapid method for fallowing the transfer rate More accurate data necessary for calculatshying the overal mass transfer coeffiaeats at each of the three salt-metal interfaces were obtained by analyzing samples of the salt aM bismum phases for total teo-dymium via an isotonic dilution mass spectrometry technique Use of this technique avows measurement of neodymium concentrations as low as OJOI ppm (wt)
811 of Salt J to Metal MTF3
The quantities ot salts and bismuth charged to the process vessels of experiment MTE-3B are listed in Table 81 AD internal surfaces of the carbon-steel vesshysels were hydrogen treated at 650degC for V7 hr to reshymove any oxides prior to the addition of the salt and bismuth solutions The auxiliary charging vessels used in the additions were also hydrogen treated Subsequently a purified argon atmosphere was maintained in all the vessels to prevent oxide contamination (via ingress of air or moisture) of the vessels and process solutions
The charging vessels were IO-in-diam (0_25-m) carboa-steH vessels o f about 22 liters (0022 m 3 ) in volume equipped with electric heaters for melting the salts and bismuth Nozzles and access ports were pro-
Tabie8l Qwtit iet ot salts and tnsmmtk for o u M i w f t MTE-3B
Material Vessel Volume at
650C (liters)
Wesgh (kg) f-moles
Fluoride fuel salt Reservoir 294 970 5lt (72-16-12 mole LiF-BcF -ThF)
Fluoride fuel salt Contactor 31 102 161 (72-16-12 mole LiF-BeF-ThF)
Bismuth-thorium | M 500 ppm (wt) Th Fluoride salt 29 276 132 MO ppm Li| side of contactor
Bismuth-thorium [M500 ppm (wl)Th LiCI side of 35 33 161 M 0 ppm Li| contactor
Lithium chloride Contactor 29 43 101
Lithium chloride Stripper 38 56 132
Bismuih 5 at lithium in Stripper 43 418 200 stripper
Demiliev at 650C fluoride fuel salt 330 gcc LiCI = 1 AS gcc Bi 96 gcc Mole weight = 632 g
144
video for the addition of the salts and bismuth argon and hydrogen purge gas ones and hues required to transfer the salt and bismuth phases into the process vessels
Bismuth hydrogen treated in the charging vessel to remove oxides was the first material to be added to the contactor The fluoride fuel salt was then contacted in the charging vessel (using argon sparging) with a bismclaquoi-OIS wt thorium solution (50 of Th satushyration) for several days prior to transfer into the fuel-salt reservoir and the fluoride salt compartment of the contactor Thorium metal (01197 kg) was then added to the 614 kg of bismuth in the contactor This quanshytity of dtorium is about 50 of the amount that would be soluble and was calculated to produce a lithium conshycentration ot ^-40 ppm (wt) in the thorium-bismuth phase in the contactor based on previously reported data1 on the distribution of thorium and lithium beshytween molten bismuth and fluoride fuel -alt
FoBowing the additions of bismuth to the contactor and the fluoride fuel salt (72-16-12 mole LiF-BeF2-ThF 4) to the contactor and fuel-salt reservoir a new charging vessel was installed for makeup and charging of the bismuth-5 at lithium to the stripper and the LiCI to the contactor and stripper First bismuth was added to the charging vessel and was hydrogen treated to remove oxides by sparging with hydrogen at v-oOOC (873degK) for laquoraquo7 hr The charging vessel contained 6787 kg of bismuth to which was added 0120 kg of lithium metal to produce the bismuth-5 at lithium for the stripper Part of the bismuth-5 at lithium solution (41 amp kg) was then transferred into the stripper vessel
Thorium metal (0109 kg) was added to the 26 kg of bismuth-lithium solution remaining in the charge vessel and 1588 kg of LiCI that had been oven dried at 200degC (473degK) was added to the charge vessel The bismuth-lithium-thorium and LiCI phases were sparged with argon using a gas-lift sparge tube for four days The LiCI was then transferred into the LiG side of the conshytactor and the stripper vessel
The salt and bismuth solutions were filtered through molybdenum filters [^30 u (30 X I0~ 5 m) in pore diameter] installed in the transfer lines during transfer
- from t^e charging vessels into the MTE-3B process vessels
812 Run Nd-I
For the first run in MTE-3B 3300 mg of NdF (2360 mg of Nd) was added to the 97 kg of fluoride fuel salt (72-16-12 mole LiF-BeF2-ThF4) in the fuel salt resershyvoir on June 6 1975 The neodymium contained 722 mCi of TNd tracer (tVi - 11 days) at the time of
addition The neodymium concentration in the fuel salt in the reservoir was calculated to be 24 ppm (wt) which approximates that expected in the fuel salt of a single-region lOOO-MWie) MSBR Neodymium was chosen as the representative rare-earth fission product for the first series uf experiments in MTE-3B for several reasons
1 results could be compared with those obtained using neodyrahnn in the previous experiment4 MTE-3
2 Sd tracer used for following the rate of transfer of neodymiuni has a relatively short half-life (11 days) which would prevent excessive levels of radioshyactivity in the experimental equipment as additional neodymium containing 4 7 N d was added to the fuel salt during the expert-went
3 neodymium is one of the more important trivaknt rare-earth fission products to be removed from MSBR fuel salt
An attempt was made to start the first run (Nd-I )on June 91975 However a malfunction in the electronics of the speed control unit for the stripper-vessel agitator prevented startup After this unit was repaired run Nd-1 was started on June 15 1975 and the scheduled period of operation (100 hr) was completed on June 20 1975 Operating conditions of run Nd-I were 650 to 660CC (923 to 933degK) 5 rps agitator speeds in both contactor and stripper fluoride salt flow rate of 35 ccmin (58 X I 0 1 m 3sec) and LiCI flow rate of 12 litersmin (20 X IO 5 nrsec)
After 100 hr of fluoride salt and LiG salt circulation the fluoride salt circulation was stopped and the run was continued for 16 hr This was done to observe the expected large decrease in the concentration of neoshydymium in the smaller amount of fluoride salt in the contactor (102 kg) as compared with the 1072 kg contained in both the contactor and reservoir These data would provide a more accurate measure of the rate of transfer of neodymium across the fluoride salt-bismuth-thorium interface
Finally the circulation of LiG was also stopped The agitators in the contactor and stripper vessels were then operated for ^24 hr over a three-day period (8 hr each day) to allow the salt and bismuth phases to equilibrate in an attempt to determine neodymium distribution coefficients between the phases
3 L M Ferris Equilibrium Distribution of Actinide and Lanthanide Elements Between Molten Fluoride Salts and Liquid Bismuth Solutions Inorg Nucl Chem 32 2019 35 (1970)
4 Cfiem Ttchnol Dir Annu Prop Rep March 31 1973 ORNL-4883p 25
145
The experimental equipment operated safisfacturBy throaghout ran Nd- I AH operatiag variables were maia-taiaed at desired coaonioas Results obtained during run Nd-I are discussed in Sect 814
SI J Ran Nd-2
Run Nd-2 was done with the sam operating condishytions as ran Nd-I except for run deration (119 hr inshystead of 100 hrraquo Prior to run Nd-2 3590 mg of N d F
(250 tog of Ndgt coalaaaag 101 mCi of 4 7 N d tracer was added to the 97 kg of fad salt in the reservoir Including the ncodVaaum leinainaig in the furl salt at the end of ran Nd- I estimated to be 18 ppra ltwt) the neodymium concentration in the fuel salt in the resershyvoir at the start o f run Nd-2 is estimated to be 45 pom The neodynaum concentration in dte fuel salt in the contactor is estimated to be 9 ppm at the start of run Nd-2 We are uncertain of the amounts of neodymium in the other phases at the beginning of run Nd-2 as discussed in Sect 814
Run Nd-2 was started on July 13 1975 and was tershyminated on July 19 1975 after 139 hr of operation During the first 50 hr of operation the rate of transfer of neodymium into the lithium-bismuth phase in the stripper appeared to be about the same as observed during run Nd-I based en counting of the | 4 7 N d tracer in samples taken at regular intervals After about 60 hr of operation the transfer of neodymium into the bismuth-lithium phase in the stripper suddenly stopped and it was observed that neodymium was being exshytracted from the bismuth-lithium phase in the stripper into the LiCl in the stripper and contactor During the run a significant decrease in the emf between the stripshyper vessel and the contactor occurred (from ^160 mV to ^25 mV over a 30-hr period) indicating loss of lithshyium reductant from the bismuth-lithium phase The run was terminated after 139 hr of operation when it beshycame clear that useful information could no longer be obtained and it appeared that fluoride salt was being entrained into the LiCl in the contactor
814 Discussion of Results
Subsequent investigation and results of chemical analshyyses of samples of the salt and bismuth phases indicate that fluoride fuel salt was being entrained into the LiCl in the contactor throughout both runs Nd-I and Nd-2 Estimates of the amount entrained are shown below
Estimated amount of fluoride a l l transferred into LiCl Baas of estimate
Nd-I | I 0 laquo hr) Nd-I and -2 (Jul hr)
0292 kg Fluoride in IiO phase 0607 kg Thorium in B I - L I phase 0400 kg Increase in LKI level in
stripper
Based j a flaoriae analyses of 1X1 maple T taken daring nm Nd- I the enuaaaaeat of flaoride salt appears to have occurred at a relatively constant rate throaghoat the ran The total amount of neodyaaam which transshyferrer into the Li-K phase in the stripper daring ran Nd-I is estimated to be 300 mg The aaaoaat of aeo-dynaam contained in the entraiaed fad salt isestiuated to be 6 mg That most of the neodynaam which transshyferred into the Li-Hi in the stripper vessd was by mass transfer rather than as a result of eatiaauaeM
The reason for the ubstivtd enfaauaeat is not dear at present One explanation K that the 50-rps agitator speed is saffident to cause enirainment (entrainmeat of flaoride salt into the chloride salt occurred in the preshyvious experiment MTE-3 at 67 rps bat not at 5JO rps) Experiments are in piogiess for deternaaing whether this explanation is correct and results to date indicate that entranirmi does not occur at 3 3 rps Further experiments in MTE-3B w i l depend on determining the reason for the unexpected entrainment of fluoride nt into the LiCl- However it appears feasible to continue rare-earth mass transfer experiments in MTE-3B by removing the LiCI (contaminated with fluoride salt) and the Li-Bi solution from the stripper vessd after which purified LiCl and Li-Bi solution will be added to the system
The main nurpose of the metal transfer experiment is to measure mass transfer coefficients for the rare eanhs at the various salt-metal interfaces in the system and to determine whether a literature corrdation5 (based on studies with aqueous-organic systems) which relates many transfer coefficients to the agitator speed and other physical properties of the system is applicable to molten salt bismuth systems Data obtained from run Nd-I have been analyzed and estimates have been made of overall mass transfer coefficients for neodymium at the three salt-metal interfaces Even though entrainment of fluoride salt into LiO occurred during run Nd- I it is believed that the mass transfer rate for neodymium was not 5ignificantly affected The concentration of fluoride in the LiCl at the end of run Nd-I was vl_ wt 1 or 003 mole fraction Based on previous studies6 the disshytribution coefficient ) for neodymium between the molten bismuth-thorium solution and LiCl (mole fracshytion Nd in bismuthmole fraction Nd in LiCl) would be decreased by ^ 2 0 7 while the distribution coefficient for thorium would be decreased by a factor of ^150 This would result in a decrease in the separation factor
5 J B l-ewii Chan En Sri 3 24S 59 119541 6 I M Ferris el raquo Distribution of Lanthamde and
Actinide Klements Between Liquid Bismuth and Molten IKI-Iil- and liBr-lil Solutions Inorg ucl Chart 34 313 20(1972)
146
were t in
VIO to vIO1 i transferred
bull t o the Lid The ate of leaver of neodynuua across the three
byaaslysesofi the m Two analytical i
(1) coasting of the OS34acV by the 4 N i tracer aad (2)iKgttopicduu-
spectroaaetry luaed on ccejufhag of the 4 T N d tracer a aaMeriai buuare of the t w t j i i w of gt95 obtained at the end of run Nd-1 indicated that about 11 of the niudjununa mfrinaMj added to the fuel salt icaenvar had beea transferred iato the LMI irautioa at the stripper
The counting trchaiqf is a rapid method aad pro-oa the rate of transfer wide the mas llwwcui it does ant provide the
required for calculation of the overal mas transfer coefficients particalariy in the K-Th aad Lid
bull the contactor aad stripper vessels in which the less than 1 ppm
(wt) The isotonic ddutioa analysis is capable of accushyrately determining neodynmm conccntntioa down to -VOJOI ppmfwt) and resorts obtained from the isotopic duvtioo tednaque for the Bs-Th and LiCI phases were used for calculations of the overall mass transfer coeffishycients
Values for distribution coefficients for neodymium at the thru salt-metal internees were measured at the end of run Nd-1 for comparison with those calculated from the dau of Ferris3 bull (Table 82) The experimental values are in reasonable agreement with the calculated values in the absence of fluoride contamination indicashy
ting that the distrnVstsoa coefficieau for neodynnum were not seriously affected by the entKnuncnt of the fluorine sah into the chloride
Data obtained during run Nd-1 were analyzed by inuahawiiui solution of seven tune-dependent differenshytial mm rial twlanu equations (Fig 8 J ) that relate the
v i imdash F t laquo r V
raquo i W W F a laquos-X4gt
V j j l laquo bull Klaquoa (X-IVCraquo)-F(Xs-)^
V - MOLAR VOLUME OF EACH PHASE
F bull FLOW RATE MOLESSEC
7 L M Perm et d Distribution of Lanthannte and Actiniae Element Between Molten Uthium Halide Salts and Liquid Msmuth Solutions Inorg Piuci Oirm 342921 -33 lt1972)
OLOLDc RARE-EARTH DISTRIBUTION COEFFICIENTS MOLESMOLE
A AREA AT EACH INTERFACE CM
TaMrSJ Dutrwatioa coeffionrta for mod m msit iauat MTE-3B ran Nd-1
Salt-metal interface Calculated Experimental
Fluoride salt-Bi-Th LaO-Bi-Th LiQ-Li-Bi
0006 094
3-5 X 10
0013 064
gt I X I0raquo
Distribution coefficient laquo (mf Nd in bismuth)(mf Nd in salt) ^Conditions 6S0C (923degK) Li concentration in Bi-Th 40 ppm Li concentration in Li-Bi = 5 at no fluoride in LiG phase
K I KbdquoK gt RARE- EARTH OVERALL MASS TRANSFER COEFFICIENT CMSEC
X gt RARE- EARTH CONCENTRATION IN EACH PHASE MOLESCM
EQUATIONS USEO TO CALCULATE MASS TRANSFER COEFFICIENTS FOR METAL TRANSFER EXPERIMENT
MTE-3B
F raquo S X Equations awd to calculate maw traaafer coeffishycients for the metal Mifer p r a m experiment V volume of each phase x - rare-earth concentration l = lime A - mass transfer area F raquo flow rate D bull rare-earth distribution coeffishycient K = overall mass transfer coefficient
147
rate at which the rare earths r ~ transferred through the several stages to the distribution coefficients of the tare earth the mass flow rates and the mass transfer coeffishycients at each salt-metal interface The set of equations was solved using a computer program by selecting values for the mass transfer coefficients which resulted in the best agreement between the experimental data on rate of change of neodymium concentration in aB phases in the system and the calculated values Several trial-and-error iterations were required using adjusted values of mus transfer coefficients until a best-fit solution was obtained
The final calculated results for run Nd-1 are shown in Table 83 where the values for the overall mass tkjnsfer coefficients are given and are compared with values calshyculated by the correlation of Lewis5 The coefficients are lower than predicted and are similar to results obtained in the previous experiment MTE-34 Final analytical results for run Nd-2 are not yet available However for the first SO hr of operation the rate of accumulation of neodymium in the Li-Bi solution in the stripper appeared to be similar to that observed in run Nd-1 The significance of these absolute values of mass transfer coefficient cannot be assessed until the scaling laws in this type of contactor are known
8 L E McNeeje Engineering Development Studies )or Molten-Salt Breeder Reactor Processing o II ORNL-TM-3774 (in preparation)
8 2 SALT-MSMUTH CONTACTOR DEVELOTMENT
CH Brown Jr
Mechanically agitated nondispening salt-bismuth conshytactors are being considered for the protactinium removal step and the rare-earth removal step in the reference MSBR processing plant flowsheet These conshytactors have several advantages over packed-column salt-bismuth contactors
1 they can be operated under conditions that minimize entrainment of bismuth to the fuel salt returning to the reactor
2 they can be fabricated more economically from graphite and molybdenum components
3 they can handle more easily large flow-rate ratios of tismuth and molten salt
Experimental development of stirred interface contacshytors is being carried out in two different systems a facility in which molten fluoride salt is contacted with bismuth containing a dissolved reductant and a system in which mercury and an aqueous electrolyte phase are used to simulate bismuth and molten salt These two systems and the development work performed during this report period are described in Sects 821 and 822
Table 8J Oven mass transfer coeffkieM for iteodymmm m metal master experiment MTE-3B ran Nd-1
A (mmsec) A (mmsec) A (mmjecr
Measured1 Predicted value value ltlt)
Measured Predicted value value Cr)
Mease bdquod c Predicted value value i^)
00035 39 025 20 013 25
Based on the neodymium in the salt phase 1 I I
bmdash~ - mdash mdashmdashmdash at fluoride salt -Bi -Th interface
I D B
I l
at LiCl-Bi-Th interface
a LiO - Li-6i interface A j km k9Ds
= individual mass transfer coefficient fluoride sail to bismuth - individual man transfer coefftcien bismuth to Tuoride sail = individual man transfer coefficient bismuth In lithium chloride k - individual mass transfer coefficient lithium chloride to bismuth
where
DA - distribution coefficient between fluoride salt and bismuth Dg - distribution coefficient between chloride salt and bismuth Oc distribution coefficient between chloride salt and lithium-bismuth
cAgitator speed is 50 rps
MS
S 2 I Expernieafe win a fecsnmkaly Agitated Nnaaraquoprning Contactnr bull the Salt bull f a i t h
Flolaquortuumgt FariSty
Operation of a facility has continued in which mass transfer rates are being measured between molten LiF-BeF 2 ThF 4 (72-16-12 mok )and molten bismuth m a mechanically agitated nondispeising contactor The equipment consists of a graphite-lined stainless steel vessel salt and bismuth feed and receiver vessels and the contactor vessel h the first of these the salt and bismuth phases are stored between runs The other vessels allow for treatment of the phases with HF and H The comactor consists of a 6-ltn-diain carbon-steel vessel conta rang four I-in -wide vertical baffles The agitator consists of two 3-in-dhm stirrers having four noncanted blades A ^-in-dtam overflow at the intershyface allows removal of interfacial films i f present with the salt and metal effluent streams During a run the salt and bismuth phases are fed to the contactor by conshytrolled pressurization of the respective feed tanks the phases return to the receiver vessels by gravity flow A detailed description of the facility and operating proshycedures has been previously reported A total of nine mass transfer runs have been completed to date along with one hydrodynamic run intended to determine the amount of entrainment of one phase into the other at a sties of different agitator vxeds Results from the nine mass transfer runs have been previously reported ~ i
The experimental proceduie for and results obtained from the hydrodynamic run and treat men of the salt and bismuth with HF and H 2 are discussed in the reshymainder of this section
Experimental operation daring the hydrodynamic ran The hydrodynamic run was performed with salt and bismuth flow rates of M 5 0 and M 4 Q ccmin respectively The agitator was operated at three difshyferent speeds during the run 250310 and 386 rpm At 250 and 310 rpm three sets of unfdtereJ salt and bisshymuth samples from the contactor effluent streams were taken at 4-min intervals Three sets of unfiltered efshyfluent samples were aiso taken with the agitator operatshying at 386 rpm but the samples were taken at 2-min intervals
To avoid contamination of the sample contents with extraneous material the sample capsules were cleaned of foreign matter by the following procedure Gross amounts of salt or bismuth were first removed with a file then the sample capsule was polished with emery cloth and finally (he capsule was washed with acetone
The sample capsules were then cut open with a tubing cutter and the contents of each sample were drilled out
and visual)- inspected for the presence of one phase in the other Ho such evidence of gross entramment was found h some of the salt samples small flecks of metal were noticed which were probably small pieces of the sample capsule produced during the dnamg operation The contests of each sample were then sent to the Ana rytical Chemistry Division for dttuiiannion of brsrmnh present in gt salt samples and berynram present in the bismuth samples h is assumed that any berynmm present in the bismuth is mdkstive of entrained fluoride salt The results of these analyses are given in Table 84 The bismuth concentration in the salt samples shows a general decrease with increasing sarrer speed widi very low values occurring at the highest stirrer speed It also seems evident that the bismuth concentration in the salt phase may have been a function of the run time since after the fourth sample the bismuth concentration reshymained at a relatively constant value of 50 plusmn11 pom which is quite different from the values reported for the first four samples which ranged from 1800 to 155 ppm
These results are significantly higher than those of LindauerJ who saw less than 10 ppm of bismuth in
9 J A Klein el al tnaraquoeerme Development Stmmes far I M l d i U t Breeder Reactor hocesnm So bull ORNL-TS-463 Italy 1975) pp 2 3S
10 C H Brown Jr Engmttii-t Development Studies for Molten Salt Breeder Reactor rYoceomf So 21 ORNL-TM-4X94 (in preparation)
11 J A Kkai tnemeermw Drreiopmenl Studies of Molten-Smll Breeder Reactor Procenmt So IS ORNL-TM-469 (September 1974) pp I 22
12 C H Brown Jr Enjmerrmt Development Studies for Hoten Salt Breeder Reactor rVncezshu Vo 20 ORNL-TM-4810 (in preparation)
13 R B LindraeT fmjmeetmf Drreiopmenl Studies of Molten Salt Breeder Reactor Proceowtt So 17 ORNl-TM-41711 (m preparation)
TaWeS4 Kwmyraquoof ^aXmmhwmmmtn
Agitator speed Bi sample Be in Bi Sail sample Bi in salt (rpm) number (ppm) number (ppm)
250 42 215 437 100 250 429 125 43 205 250 430 215 439 155 310 431 85 440 270 310 432 910 441 53 10 433 442 34
36 434 110 443 64 36 435 175 444 54 36 436 50 445 43
149
fluoride salt in comact with b i t iu fh in several different contacting devices- It is likely that sample i nniiuuni tioa is a contributing factor to the high bcrmdashrh concenshytrations measured Three possible sources of sample coataaunaboa have been reported
I timtjuunitiou by withdrawing Imdashparr through a sample port which has been in contact wkh bismuth
analytical laboratory by the use of equipment roushytinely used for bismuth analyses
3 ctrwfuttiiuTmutftoit from bull hwy^CTWffy vt^tt^f^n^i^^^^UKttf material laquohkh may be floating on the salt surface
Since no maximum peiHUSMuk rate of bismuth eMram-ment in the fuel salt going to the bism ah removal step or m the salt returning to the reactor from the fuel processing plant has been set it is difficult to assess the significance of these results However the bismuth conshycentrations in the salt do not seem to be inordatttelv high at the highest stirrer speed and it seems Bkefy that some degree o f phase dispersal might be tolerated ia order to achieve higher mass transfer rates
The beryflium concentrations in the bismuth samples at each agitator speed show both high and low values with no discernaWe dependence on agitator speed These results agree well with previously reported data1 for beryllium concentration in the bismuth phase during mass transfer runs in this system at agitator speeds of 124 180 and 244 rpm Previous experiments with water-mercury and organic-mercury systems suggest entrainineni of the light phase into the heavy phase at an agitator speed of about 170 rpm The concentration of beryllium in the bismuth phase is not significantly different from previous results observed at lower agitashytor speeds The effect of entrsined fluoride salt in the bismuth would be most detrimental in the metal transshyfer process where fluoride salt in the chloride salt phase decreases the separation factors between thorn m and the rare-earth fission products
H -HF treatment of salt and bismuth The mass transshyfer runs completed to date in he salt-bismuth contactor have all been performed under conditions where the controlling resistance to mass transfer is in the inter-facial salt film One final mass transfer run will be pershyformed in which the bismuth-film mass transfer coeffishycient is measured In preparation for this run the salt and bismuth in the graphite-lined treatment vessel were treated with HF diluted with H 2 to oxidize the reduc-tants present in the bismuth phase The procedure used was essentially that reported previously14 The salt and bismuth at -v-oOOC were sparged with 25 scfh of 30 (mole) HF for 9 hr The HF utilization decreased from
7 5 at the 1 njiiiiini of treatment to 3 5 during the final 2 hr of treatmat Analysis of the ash and bismuth phases before and after treatment with HF and H 2 inshydicated that esaeatiaty a l of the rr duct ant in the bisshymuth phase was oxidized by hydrofluormatioa The mmtmm distribution ratio decreased from 740 molts mole prior to the treatment to OJ03 molemole after the HF-Hj treatment
L U ---r--8 iiiiiT I M I I I M M I U I I - j
We have continued development of a mrrhmii dlj agitated nondispersmg two-phase contactor wing an aqueous electrolyte and mercury to srmmatf mohea salts and bismuth
As previously reported1 we have investigated the feasibility of using a pobrographk technique for measuring electrolyte-film mass transfer coefficients in this type of contactor During this report period we have
1 tested three different anode materials 2 produced cathodk polarization waves corresponding
to the reduction of F e compkxed widi excess oxalate ions at the mercury surface
3 obtained and calibrated a slow-scan controDed-potential cyclic volumeter
4 examined the quinone-hydroquinone redox couple as a possible alternate to the F e -Fe couple now being used
Modifications to experimental equipment With the exshyception of the tests made with the qrinone-hydroquinone redox couple ail tests made during this pr ied were performed with the equipment previously described5
The equipment consists of the 5 X 7 in Plexiglas conshytactor used in previous work with the water-mercury system The mercury surface in the contactor acts as the cathode in the electrochemical cell The cathode is elecshytrically connected to the rest of the circuit by a Vg-in-diam stainless steel rod electrically insulated from the electrolyte phase by a Teflon sheath The anode of the cell is suspended in the aqueous electrolyte phase and consists of a metallic sheet formed to fit the inner perimeter of the Plexigas cell The current through the cell is inferred from the voltage drop across a 01 -SI plusmn 05 10-W precision resistor The signal produced
14 B A Hannaford (l jl Engineering Development Studies for HollenStll breeder Reactor Processing No 3 ORNL-TM-3l3ltMay 1971) p 30
15 C H Brown Jr Engineerin Development Studies for Mitten-Sit Breeder Reactor Processing So 22 ORNL-IM-4041 tin preparation)
ISO
on a on the
electrode
across the i Hevlen-Fackard xjr plotter The x nbtter bull nrodnoed hy the | the mncmy and a (SCE) suspended in the electrolyte |
to studies nun on the a stow-wcan controned-pocentieJ cyclic woks
patentNttat) was obtained fan the Analytical Chemistry Dtaunu to repfacr the Hewlett-Packard dc poawaapfiy iwtiionely wcd-ThecycJCfohnnrtrTiia three electrode mstrumeut which cortroh lraquo i bttnicn the mercury vnfuir and ai reference electrode whle paahag a cnrrent between the auxamry electrode and the mercury surface Voitafes can be itianrJ between tfVw SCE aad -2 Vw SCE ataacanrateaptol Vnnh The posentiostat can carry a carrot of up to 2 5 A between the auxSnry and mtiiury electrodes
npunninli ahh Ihi tt1 fi ililiai Thr rlrriin ryte used for al the experiments performed daring this report period was nouunaPy OJOOI M Ft2 obtained from ferrous sulfate 0X10025 M Fe obtained from ferric salfate and 0 J M potassium oxalate The oxalate ions form a stable complex with both the re and Fltr2
ftriuuif mnmumnm of the Fe1 reduction cdhccdy
Three anode nMcriab have been tested copper iron ml satisfactory polarization -aaves were pro-
I with al three materials However the copper and iron reacted with the electrolyte solution This addishytional uue reaction caned poor lewudacnwwty in the
I could aho p ornery alter the properties of the To amid tins cnobkrn an anode was fabrishy
cated by poring gold on a 0J062$-m-thka sheet of nickel which was formed to fit the inner perimeter of the electrochemical eel
Shown irgt Fig 8 J is a polarogram measured with the electrolyte described above in the 5 X 7 in Plexiglas contactor mag the gold anode with phase volumes of aboat IJ8 liters each and nc agitation The cell current it plotted as a function of the mercury sarface potential vs the SCE The cnrrent racreasts from zero at zero applied potential to a relatively constant value at an applied potential of about -035 V n SCE In this region contbtvons electrolysis is taking place in the cell corresponding to reduction of FetCiO^ 1 ~ at the mershycury cathode In the region of applied potential from -0J5 V vs SCE to -0JO V vs SCE the cell current
OMM 0W6 79- U429
1 1 1 1 1 1 1 S
2 lt
bull0t-M raquo raquo
m m m f~~ 5 u J I
J ew0^45V
ffl 1 1 1 1 1 0 -OJ -02
Fugt laquo3 Catholic bullohriarmi ware for FlaquoC O)
-0 5 -04 -OS VOLTM0C raquobull SCE
-OS -07 -oa
in Ac 5 X 7 J n m l raquo
151
increases only a smal iniaswt here the current is bullanted by ttugt rate of diffusion of the Fe(CzQlaquogtjgt~ to the mercury surface where this ion is rcdnced The difshyfusion current can be related to the nam transfer coefficient through the electrolyte fifan as prcwontly
The half-waw potential is defined at the potential at which the current is equal to one-half the hunting nine Figure 8 J shows the measured half-waw potential for the ferric oxalate coaapiex The half-wane potential of -0245 V measured in the contactor agrees weD with the wine reported in the literature of -024 V vs SCE for the reduction of ferric oxalate
Under ideal conditions the diffusion current is directly proportional to the polarized electrode surface area and the bulk concentration of the hinting km To detennine that the mercury surface was actually being polarized two tests were perfonned First the anode surface area was decreased by about 48 This had no effect on the magnitude of the diffusion current indishycating that the mercury surface (cathode) was polarized rather than the anode surface In the second test the concentration of the ferric ion was doubled but no concomitant increase in diffusion current was seen Since the diffusion current is directly proportional to the concentration of the limiting km (Fe1) the current should haw doubled The only explanation for this behavior is that the Fe had been reduced by some contaminant in the system possibly present in the mershycury This would have caused ferric ions to be present at only a wry low concentration during ceD operationdue to electrolytic oxidation of the ferrous iron
To ebminate the possibility of reductant being present in the mercury a supply of purified mercury was obshytained from the Analytical Chemistry Division A test was performed using the purified mercury and an elecshytrolyte having the same nominal Fe and Fe concenshytrations given abow Preparation of the electrolyte was completed in the absence of oxygen to preclude posshysible oxidation of Fe to Fe Again the anode surshyface area was decreased with no discernible decrease in the diffusion current indicating that the mercury surshyface was polarized An increase of the Fe concentrashytion from M)25 vnM to Mgt3 mW resulted in an inshycrease in the diffusion current by a factor of 2 indishycating that the waw being measured was the ferric ion reduction waw However the half-wave potential was measured to be -07S V vs SCE which is about three times the reported value
To calculate the aqueous-film mass transfer coeffishycient from poiarographic data the bulk concentration of the oxidized species must be accurately known The
n a n K amp j f a u f l l O u l a m m anuCntSnafsEafannTuB a m m nWanuWOnBTBsnnnnnT- ana^ne-w w ^ m w u^m w ^ p p ewajuajuaawmimaaaBmniw ma mi awnwaawgt^pwnnawBwanpap wa^anu
the electrolyte used in dm second of the two ter^jaen-tkmed abow woe analyzed for F e v asm F by this method Results hnhcatrd that the fie and Fe conshycentrations were 17 and 028 mMrespectiwry which is in poor agreement with the expected values of 030 ajtf Fe and 1J0 mmf Fe2 One poanok cause for the poor agreement is that the Ft 1 was oxidized to Fe during the period when the solution was held in the sample bottles However this was not expected since the dec-trotyta had been sparged with argon to remow dissolved oxygen and the sample botdes were purged with argon toremowair
To aid in oetennming if the reported analytical results were in error due to analytical technique or to method of solution preparation two standard solutions were prepared and sampled for analysis One solution was prepared to contain 56 ugim Fe and the other solushytion was prepared to contain 56 ugnd Fe1 Both solushytions were 1 WmKjCzO^HjO Subsequent analytical results indicated that both solutions had essentialy the same concentrations of Fe3 and Fe 1 50 and 27 fignil respectively Farther investigation wnl be necessary to determine the correct method for preparing andor analyzing iron oxalate solutions
Experiments with the qwmame-bydroonmmae system A possible alternate to the Fe -Fe system for measshyuring electrolyte-phase mass transfer coefficients is the reversible reduction of quinone to hydroquinone at the mercury cathode
The reaction under consideration is
C r l 4 0 + 2 H 4 + 2laquo-CHlaquo(OH) ( I )
Since hydrogen ion as wen as quinone is a reacting material a strong buffer must be present to serve as a supporting electrolyte The buffer causes the H conshycentration to be essentially constant across the inter-facial electrolyte film because the rate at which the buffer equilibrium is established is reiatiwfy rapid comshypared with the quinone diffusion rate1
A quaUtatiw test was made with the quinone system to determine whether acceptable polarization waves couM be measured and to determine whether the quishynone electrolyte is inert to mercury The electrolyte was 001 M hydroquinone and 0005 M quinone with a 0O5 M phosphate buffer at a pH of 70 Satisfactory polari-
16 i M Kolfhoff and 11 Latcanc p 44 inbfaromvp Intencfcnce New Yortt 146
I C A Lin el at Dirruson-Controiled Electrode Reacshytions Ind Eng Ckem 43 2136-43 (1951)
1S2
abon waves were obtained in a small cell with a large copper anode and a mercury pool cathode The electroshylyte was chemically inert to mercury during the tests The color of the quinone electrolyte changed from a light yellow to deep brown within several hours This phenomenon is due to the decomposition of quinone by ultraviolet light Further studies in the S X 7 in contacshytor will be done to determine whether tins system is suitable for mass transfer measurements
8 3 C0NTTNU0USFLU0IUNATOR DEVELOTMENT
R B Lindaucr
Continuous fluorinators arc used at two points in the reference flowsheet for MSBR processing The first of these is the primary fluorinator where 99 of the uranium is removed from the fuel salt prior to the reshymoval of 2 J J P a by reductive extraction The second point is where uranium produced by decay o f 2 Pa is removed from the secondary fluoride salt in the protacshytinium decay tank circuit These fluorinators will be protected from fluorine corrosion by frozen-salt layers formed on the internal surfaces of the fluorinator which are exposed to both fluorine and molten salt To keep frozen materia on the walls while maintaining a molten-salt core in the fluorinator an internal heat source is necessary to support the temperature gradient Heat from decay of the fission products in the salt will be used in the processing plant However to test frozen- JI fluorinators in nonradioactive systems
another internal heat source which is not attacked by fluorine is needed Since electrolytic or autoresistance heating of molten salt has proven to be a feasible means fx providing this heat source studies of auforesbtance ucating of molten salts are continuing A conceptual design was made for a continuous fluorinator experishymental facility (CFEF) to demonstrate fluorination in a vessel protected by a frozen-salt film Design was comshypleted and installation was begun of a fluorine disposal system in Building 7503 which uses a vertical spray tower and a recirculating KOH solution Installation was completed of equipment to demonstrate the effectiveshyness of a frozen-salt film as protection against fluorine corrosion in a molten salt system
8 J I autafetmi and Initial Operation of Aaloteststance Heating Test AHT-4
Equipment for autoresistance heating test AHT-4 was installed in ceil J of Building 4S0S fai this system (Fig 84) molten LiF-BeFj-ThF (72-16-12 mole 7r) is cirshyculated by means of an argon gas lift from a surge tank to a gas-liquid separator from which the salt flows by gravity through the autoresistance electrode through the test vessel and returns from the bottom of the test vessel to the surge tank The test vessel (Fig 85) used in experiment AHT-3 was decontaminated equipped with new cooling coils heaters and thermocouples and reinstalled for experiment AHT-4
The test vessel is made of 6-in sched-40 nickel pipe with a 44-in-)ong (II-m) cooled section from the elecshytrode to below the gas Inlet side arm The cooled secshytion is divided into five separate zones each with two
Oflm 0tJngt 79mdash4W5
bullbullOfF-CAS-
j M M N m laquo$urr|
SCMMTOft
JT~f
i II lraquo li II I I I I
Hi
HEAT FLOWMETER
AUTOMESISTANCC HCATIN6 POWER
SUff lV TEST
VESSEL
ARGON
Fig SA Ftowdwet for autoresifUncc heating test AHT-4
153
Ffc85 AHT-4 lest vewd
154
parallel coils through which an air-water mixture flows The gas outlet section above the salt level has an inshycreased diameter for gas-calt disengagement and is made of 8-io sched-40 pipe The surge tank has a 46-m4ong (I _2-m) 6-in-diam (01 S-m) section to provide submershygence for the gas lift The upper section of the surge tank is 24 in (0-61 m) in diameter and provides suffishycient capacity to contain the salt inventory for the enshytire system The gas-liquid separator is an 8-in-diam (O^Om) conical-bottom vessel with baffles and York mesh in the upper part for gas-liquid disengagement m the heat flowmeter the salt is heated by an internal cartridge heater and the flow rate is calculated from the heat input and ihe temperature iise of the uit stream
The system is started up by heating the equipment and Hnes to 600C (873degK) The argon gas lift is started and initially the salt flow rate is determined by the decrease in surge-tank liquid level After the salt levels in the tank separator and test vessel are constant cooling of the test vessel is started The resistance beshytween the high-voltage electrode and the test vessel walls is checked periodically by applying a low voltage
to the electrode and measuring the current As cooling progresses this resistance wul increase until the point is reached where heat can be produced in the salt at a significant rate (several hundred watts) without cauang a reduction (shorting) of the resistance
The 80-liter salt batch was charged to the surge tank and after minor modifications to the heating system operation was started Four preliminary runs were made lasting from 4 to 12 hr (from the time the gas lift was started until plugging occurred) In the first run plugging apparently occurred in the electrode when the liquid level in the separator fefl too low to provide sufshyficient head for flow to the test vessel
Salt flow in the second run was much smoother and circulation continued for 11 hr without adjustment of the gas lift During this time the test vessel was being cooled and the salt flow rate slowly decreased by V7 from 450 to 425 cnvVmin This was probably caused by an increase in salt viscosity a buildup of frozen salt in the test vessel or a combination of the two The steady salt flow rate and higher salt temperature fgt873 0K and 20-3TK higher than in run No 1) kept the electrode from freezing but the heat supply at the bottom of the test vessel was insufficient to keep the salt outlet from freezing which terminated run 2 The resistance beshytween the high-voltage electrode and the vessel waO increased from 001 to 0X1812 but autoresistance heatshying was not attempted The vertical portion of the test
section had been cooled to 639degK (sobdus temperature 623degK)
Before the third run the output of the powerstat conshytrolling the test vessel bottom heaters was increased by 44 to keep the salt outlet above the freezing point The ran was terminated by salt freezing in the elecshytrode This resulted from too low a salt flow rale (the heat flowmeter was inoperative because of a burned out heater) and too low an initial temperature (723degK vs 823degK in the second run) in the vertical section of the side arm through which the electrode passes
The fourth run was started with some heat on the vertical section of the side arm This section was unshyhealed prenocty As coohng progressed the bottom heaters on the test vessel were inadequate at the salt flow rate being used Increasing the salt flow rate preshyvented freezing at the bottom of the test vessel After 754 hr of operation the liquid levels in the separator and test vessel started to increase indicating salt flow probshylems both at the inlet and exit of the test vessel Alshythough the salt resistance had only increased from OX) I to 003 ft and the average test vessel wall temperature (in the cooled zone) was 658degK autoresistance heating was suited This freed the plug in the electrode allowshying salt flow from the separator to the test vessel and the increased flow raised the test vessel bottom tempershyature and flow resumed from the test vessel However salt flow rates were erratic for the next 2 hrand 9K hr after the start of the run the tert vessel level started to rise indicating a frozen salt restriction in the vessel It was decided to try to transfer the molten salt from the test vessel to the surge tank before complete plugging occurred This was done successfully and 56 liters of salt was transferred to the surge tank After cooling radiographs were taken of the test vessel by the Inspecshytion Engineering Department using a 35-Ci J l r source In the test section of the test vessel radiation penetration was insufficient to permit measurement of the film thickness The bottom of the vessel between the salt outlet and the gas inlet was free of salt as exshypected and the radiograph of flu top of the vessel showed a 25-mm-thick ring of salt above the normal liquid level This is salt deposited on the colder pipe wall by the action of the gas bubbling through the salt Calculations from the volume of salt transferred indishycated an average film thickness of 45 mm (a 65-mm-diam molten core) The salt resistance at the end of the run was 018 ft and the maximum autoresistance heatshying used was 450 W
The main problem seems to be the forming of a unishyform salt film Near the electrode where the hot molten
155
salt enters cooling is much slower than in the vertical section above the gas inlet It is probably in the vertical section where the salt flm becomes too thick and reshystricts the salt flow
8J2 o f Facaty(CFEF)
The purpose of the CFEF is to measure the perforshymance of a continuous fluorinator which has frozea-wali corrosion protection in terms of uranium removal The uranium which is not volatilized but is oxidized to UFs wfll be reduced back to UFlaquo in a hydrogen reducshytion column The facility wul be used to obtain operatshying experience and process data including fluorine utilishyzation reaction rate and flow-fate effects and to demonstrate protection igainst corrosion using a frozen salt Aim
The facility will be installed in a ceD in Buflding 7503 to provide beryllium containment The system wfll conshytain about 8 ft 3 (023 m J ) of MSBR fuel carrier salt (72-I6-I2 mole 3 LiF BeF -ThF4) containing OJS mole ltpound uranium initially The salt wiD be circulated through the system at rates up to 50 of MSBR flow rate (67 X I 0 m 3xc) Because of the short fluorishynator height (1 to 2 m) the amount of uranium volatilshyized will be between pound0 and 95 per pass The variables
of salt flow rate fluorine flow rate and fluorine conshycentration wil be studied by measuring the UFlaquo conshycentration in the fluorinator off-fas stream and by sam-pKrg the salt stream after reduction of UF to UF 4 The fluorinator laquo 4 have two fluorine inlets to provide data for determining the column end effects Reduction of UF 5 war be carried out in a gas lift in which hydroshygen will be used as the driving gu and also as die reduc-tant If additional reduction B required tins can be done in the salt surge tank The surge tank is designed to provide sufficient salt inventory for about 10 hr of fluorination with 95$ uranium volarihntion per pass About 99 of the uranium should have been removed from the salt batch after this period of time
The faculty flowsheet is shown in Fig 86 Salt wil enter the fluorinator through the electrode m a side arm out of the fluorine path The electrode flange wil be insulated from the rest of the fluorinator and the auto-resistance power wiD be connected to a lug on the flange The salt wfll leave at the bottom of the fluorishynator below the fluorine inlet side arm The fluorinator wall wiD be cooled by external air-water cons to form the frozen salt film which wfll serve the dual purpose of preventing nickel corrosion and of providing an electrishycally insulating film for the autorcsistance current Below the fluorine inlet the fluorinator waB will not be cooled and the molten salt wul complete the electrical
TO FLuomnc ftSPOSM STSTU
JVTO-K S S T M C C ~ T M M
TCU f
ifSEMMUl
r-Gf=imdashlaquobullmdash^ni
TOorr-cts
^ - bull I I I T Z
FMCZC VMVC
MPWCTNM COLUMN
CAS-LIFT
HVOMMCR
rO F K M I VMVI
Fit HA Conf immu flaottnalor experimental facility flow Acer
156
OfML DWG 75-15057
FLUOMNE-CONTMHNG U S
TO N 0 T OFF-GAS SYSTEM
Fjs87 Ftmnmt4mfpmtwfmtm
nrcuit to the vessel wall Since all of the uranium will not be volatilized from the salt there will be some UF 5
in the salt at the bottom of the fluorinator The luori-nator bottom exit line and reductio- column will be protected from the highly corrosive UF 5 by gold lining or plating The molten salt containing UF S will enter the bottom of the column where the salt wit be conshytacted with hydrogen The hydrogen will enter through a palladium tube which will result in the formation of atomic hydrogen and greatly increase the reduction rate to UF 4 The hydrogen reduction column will also act as a gas lift to raise the salt to i gas-liquid separator The salt will then flow by gravity to the fluorinator through a salt sampler surge tank heat flowmeter and electrical circuit-breaking pot Off-gas from the separator which contains HF and excess hydrogen will pass through an NaF bed for removal of the HF Uranium ixxafluoride from the fluorinator will also be removed by NaF Mass flowmeters before and after the NaF beds will be used to continuously measure the UFA flow rate
83J Fluorine Disposal System for Building 7503
The CFEF (Sect 832) will be the first test of the frozen-wall fluorinator using fluorine For the disposal of the excess fluorine a vertical scrubber is being inshy
stalled in Building 7503 A flow diagram of the system is shown in Fig 87 The scrubber is a o-in-diam 8-ft-bJgh (015- by 24-m) Mond pipe with three spray nozzles in the upper half of the vessel The surge lank contains 200 gal (09S m) of an aqueous solution conshytaining 15 wt KOH and 5 wt Kl This equipment is designed to be able to dispose of one trailer of fluorine (18 std m 3 ) at a flow rate of 12 scfm (9 X 10 std msec) The KOH solution wil be circulated through the spray nozzles at a total flow rate of 15 gpm (OJOOI msec) The fluorinator off-gas stream will flow cocur-rently with tnis stream The scrubber exit stream passes through a photometric analyzer for monitoring the efficiency of the scrubber
8J4 Frozen-Wafl Corrosion Protection Denomtration
Equipment has been installed for demonstrating that a frozen salt film will protect a nickel vessel against fluoshyrine corrosion ty preventing the NiFj corrosion prodshyuct film from being dissolved in the molten salt A small vessel containing 6 X I 0 1 m 1 of molten LiF-BeFj-ThF4 (72-W 12 mole ) will be used for the demonshystration (Fig 88) The fluorine inlet consists o hree concentric tubes which provide a path for an air coolant
157
FLUOraquoK IN
JL
SALT IXVCL-
OuT
- raquo F L laquo O M OUT
FlaquoSJ Ffi
stream that will be used for freezing a salt film on the outside of the outer tube The wall of the inner lube through which the fluorine will flow is 31 nils (079 mm) thick The inner lube of the fluorine inlet will not be protected from corrosion The vessel wall is also unprotected but is 280 mils (711 mm) thick Fluorine will be passed at a low flow rate (-v830 mmsec) through the salt until failure occurs which is expected in less than 100 hr at the tip of the probe near the gas-liquid-foiid interface Wall thickness measurements before and after the demonstration will show to what extent the salt film afforded protection
A flow diagram for the system is shown in Fig 89 The argon back pressure will be recorded to provide an ndication of corrosive failure Failure of the tube below
the salt film will allow some salt to leak into the argon cooling annulus The salt will be entrained up into the cool portion of annular space causing a restriction to
the argon flow The system waf be designed such that the fluorine flow is terminated automaticaly when either a low argon pressure is detected in the anrndus or when a high argon back pressure occurs
84 FUiaiWCONSnTUnON ENCINEEJUNC OEVELOTMENT
llMCounce
The reference flowsheet for processing the fuel salt from an MSBR is based upon removal of uranium by fluorinatioa to UFraquo as the first processing step 1 The uranium removed in this step must subsequently braquo reshyturned to the fuel carrier sal before i u return to the reactor The method for recombiniag the uranium with the fuel carrier salt (reconstituting the fuel salt) consists in absorbing gaseous UFraquo into a recycled fuel salt stream containing dissolved U F 4 affording to the reacshytion
UF f c(g)UF4ld) = 2UF(draquo laquo2raquo
The resultant UF S would be reduced to U F 4 with hydrogen in a separate vessel according to the reaction
U F ltdgt bull H (ggt = UFlaquo(d) bull HF(ggt (31
Engineering studies of the fuel reconstitution step are being started to provide the technology necessary for
the design of larger equipment for recomputing UFraquo generated in fluorinators in the processing plant with the processed fuel carrier salt returning to the reactor During this report period equipment previously deshyscribed was fabricated and has been installed in the high-bay area of Building 7503 This report describes instrumentation for off-gas analysis including a prelimishynary calibration curve and two alternatives for proshyviding corrosion-resistani gold linings for equipment to be installed later
The nickel reaction vessels presently installed will be used to test the salt metering devices and gas supply systems After the initial shakedown work is completed the UFraquo absorption vessel Hj reduction column flowing-stream samplers and associated transfer lines will be replaced with gold or gold-lined equipment Gold is being used because of i u resistance to corrosion by UFraquo gas and U F dissolve in the salt
1972 18 Chem Technol Dh Anim frogr Kept Mar SI ORNL-4794p I
19 R M (ounce Engineering Development Studies for MolenStll Breeder Reactor Processing So 19 ORNL-TM-4863 (July 1975) pp 38 42
158
OMN M 6 rS-OTM
FCV-3 nOccWM HASTMGS MASS FLOWMETER
ACTIVATED ALUMNA TRAP
Ffeft9 FfocM ait BtotaciiMi
841 for Analyzing Vest Off-Goes
The equipment for the second phase of the experishyment will consist of a feed tank a UF absorption vesshysel an Hj reduction column flowing-stream samplers a receivei tank NaF traps for collecting excess UF and for disposing of HF gas supplies for argon hydrogen nitrogen and UFraquo and means for analyzing the gas streams from the reaction vessels (Fig 810) The equipshyment wul be operated by pressurizing the feed tank with argon in order to displace salt from the feed tank to the UFlaquo absorption vessel From the UFlaquo absorption vessel the salt flows by gravity through a flowing-stream sampler into the H2 reduction column From the Hj reduction column the salt flows by gravity through a flowing-stream sampler to the receiver tank Absorption of gaseous UF t by reaction with dissolved UF 4 wiD occur in the IFF absorption vessel and the resultant UF5 will be reduced by hydrogen in the Hi reduction column The effluent salt is collected in the receiver tank for return to the feed tank at the end of the run
The off-gas from the absorption vessel and the reducshytion column will be analyzed for UF and for HF reshyspectively
The respective off-gas streams will be continuously analyzed with the use of the Cow-Mac gas density balance A sample stream is taken from the main off-gas stream and passed through the balance for analysis (Fig 811) These analyses wiO be used in determining the efficiencies of UF absorption and H 2 utilization
The efficiency of UF absorption will be determined by metering UF and Ax to the UF reaction vessel and determining the UF content in the vessel off-gas using a model 11-373 Cow-Mac gas density cell2 The H utilization will be determined similarly Hydrogen will be metered to the H 2 reduction column and the column off-gas wD be anayzed for Hj content also using a model 11-373 Cow-Mac gas density ceD The Cow-Mac cell commonly used as a gas chromatograph
20 Gow-Mac Instrument Company 100 King Road Madison New Jersey
159
bullWLDIN6
bull SYSTEM
Flaquo SIO Ftow lt ^ w o gt n ^ w i l M
msw NEACnON VflaquoSCL
P9E Y
f OWL DUG 7VS909
0FF-6AS
j r _^DT
KOC
ROTCTER|V] $
Ffc 811 SdMMMtic M of fMl ncomtitalfcM experiment off-gn
160
detector provides a continuous signal which varies directly with the density of the sample gas allowing continuous analysis of the sample gas stream with accushyracies of 3 to 4ft Because the detector elements are not exposed to the sample stream the gas density cell is useful in analyzing corrosive gas mixtures
Nitrogen and argon will be reference gases for the gas density cells used for analyzing the off-gas from the UF absorption vessel and the H reduction column respectively The response of the gas density cell is fairly insensitive to changes in the sample gas flow rate when nitrogen or argon is used as a reference gas2 z To measure varying Ar-UF and H2-HF ratios with the gas density detectors it is necessary to control the refershyence gas flow rate precisely However Irigh precision is not required for controlling the sampie g^ flow rate The reference gas flow rates are controlled sufficiently by rotameter and separate gas supply systems A satisshyfactory means for providing reproducible sample flow rates has been developed The sample stream is taken from the main off-gas stream (Fig 811) and flows through a capillary tube the gas densiiy detector an NaF trap to remove the corrosive constituent (UF or HF) and a bubbler to provide a constant downstream pressure The pressure upstream from the capillary is maintained at a higher constant value by means of a similar bubbler in the off-gas line downstream from the NaF trap The NaF traps provide sufficient volume in the lines so that small pressure fluctuations from bubshybles in the process vessels and in the bubblers are effecshytively damped out The flow rate is not constant (although it is reproducible) because as the concentrashytion of the sample gas changes its viscosity changes producing changes in sample flow rate under the prevailshying conditions These flow rate changes superimposed upon concentration changes in the sample stream to the gas density detector result in a nonlinear response of the gas density detector to changes in concentration The effects are reproducible however and a reproducible calibration can be obtained Such a calibration was obtained with mixtures of hydrogen and nitrogen (Fig 812)
For sample gases containing hydrogen and at refershyence gas flow rates below a certain critical flow rate hydrogen will diffuse countercurrently into the refershyence gas stream to the area of the detector elements
21 J T Wjfoh and D M Roue tor Oiromalofr US) 232 40 17)
22 C L Ouillemm and M K Auricourf (its Chromalogr I 24 29 (October 1963)
onw MG re-mo
i i i 1 bull mdash I I I I i DO 90 0
2
Ffc 812 Cafeoraam i laquo of Gow-Mac gas Oettmtf ccM MOM in fad iccoasMatioa t^mtimj claquojlaquoipmlaquoi for H ami N-
Due to the high thermal conductivity vf H the back diffusion of H can greatly affect the sensitivity of the gas density cell However if sufficiently high reference flow rates are maintained this problem can be overshycome
842 Design of the Second Fuel Reconftitutkm EjtgMecimg Experiment
The design of equipmeni for the second fuel reconsti-lution engineering experiment (FREE-2) is continuing The equipmeni for FREE-2 will be similar in design to the equipment for experiment FREE-I except for the addition of an intermediate liquid-phase sample port beshytween the UFraquo absorption vessel and the H 2 reduction column (Fig 810) In addition all vessels and transfer lines exposed to dissolved UF 5 with the possible excepshytion of the receiver lank will be gold or gold lined Gold sheet 0010 if (02S mm) thick is on hand for the fabricated liner of the UF absorption vessel Two altershynative exist for lining the H 2 reduction column and the receiver vessel interior gold plating or a fabricated gold liner
The minimum plating thickness that would probably provide a pinhole-free liniig is approximately 0005 in (013 mm) The minimum thickness for a fabricated gold liner in vessels of this size is approximately 0010
161
in (025 mm) Fabricated gold liners are economically competitive with gold plating in the thicknesses menshytioned because gold sheet is available at ERDA prccious-mctal account prices approximately S3499troy oz (SII3g) and gold in commercial gold-plating solutions is available only at market prices of about Sl64troy oz (S5J7g) as of June 18 1975 Some comparisons important in the choice between interior gold plating or fabrication of a gold liner are
1 the technology involved in fabricating a welded gold vessel is available while some technology would need to be developed for interior plating of vessels having a high lengthdiameter ratio such as the H2
reduction column 2 the time involved in both approaches is approxishy
mately the same 3 the plating will be difficult to inspect and there will
be no guarantee of pinhok-free coverage while dye penetrant examination of welded joints is available for a fabricated liner
Because it is unclear whether there is sufficient gold in the ERDA precious-metals account for lining the reshyceive tank liner gold plating is favored There is the ziditional alternative bullbull not lining the receiver tank since i orrosion of the receiver vessel by UF5 in the salt could ie tolerated and corrosion products could be reshymoved by hydrogen reduction and filtration between runs
85 CONCEPTUAL DESIGN OF A MOLTEN-SALT BREEDER REACTOR FUEL PROCESSING
ENGINEERING CENTER
D I Gray J R Hightower Jr
A conceptual design is being prepared to define the scope estimated final design and construction costs method of accomplishment and schedules for a proshyposed MSBR Fuel Processing Engineering Center (FPEC) The proposed building will provide space for the preparation and purification of fluoride sail mixshytures required by the Molten-Salt Reactor Programfor intermediate- and large-scale engineering experiments associated with the development of components reshyquired for the continuous processing capability for an MSBR and for laboratories maintenance work areas and offices for the research and development personnel assigned to the FPEC
bullORNI Knpneeriti Division
The project wSI consist of a nev three-story engineershying development center approximately 156 ft (475 m) wide by 172 ft (524 m) long The building will have a gross floor area and volume of 54300 ft 2 (5100 m x ) and 1218J0O0 ft J (34300 m J ) respectively and vhB be constructed of reinforced concrete structural sled concrete Mock masonry and insulated metal paneling The building will be sealed and will be operated at negashytive pressures of up to 0 J in of HjO (75 Pa) to provide containment of toxic materials The FPEC wit be located in the 7900 area approximately 300 ft (91 m) west-southwest of the High Flux Isotope Reactor The engineering center will contain
1 Seven multipurpose laboratories buu on a 24 X 24 ft (7 J X 7 3 m) module for laboratory-scale experishyments requiring glove boxes and walk-in hoods
2 A high-bay area 84 X 126 ft (256 X 384 m) equipped with a 10-ton (9000-kg) crane for large-scale development of processes and equipment for fuel processing at the pilot-plant level
3 A facility for preparing and purifying 16000 kg per ye-r of fluoride salt mixtures needed for the Molten-Salt Reactor Program
4 Support facilities including counting room process control rooms change rooms lunch and conference room and data processing room
5 Fabrication and repair shop decontamination room and clean storage areas
6 A truck air lock to prevent excessive ingress of outshyside air during movement of large equipment items into and out of the high-bay area
7 Two 5-ton (4500-kg) service elevators one inside the building to service the regulated areas and one outshyside to service the clean areas and to move filters to filter housings on the third floor and roof
8 General service and building auxiliaries including special gas distribution systems liquid and solid waste collection and disposal and filtered air-handling and off-gas scrubbing facilities
The experimental program planned for the building involves large engineering experiments that use 2 1 U 2 T h Be hazardous gases i F a H 2 and HF) molten bismuth and various fluoride and chloride salts Inishytially radioactivity will be limited to that necessary for low-level beta-gamma tracer experiments The laborashytory area can later be upgraded if desired for use with alpha-emitting materials at levels up to I kg of n P u
The laboratory area will consist of seven 24 X 24 ft (73 X 73 m) modular-type laboratories and a general-purpose room Bench-scale experiments of the type now performed in buildings 4505 3592 and 3541 will be
162
carried out m these laboratories FtoMems encountered in the large-scale experiments can be studied via smaE subsystems Inert-atmosphere glove boxes wil provide space for examination of samples removed from both the large and the small experiments The laboratory area wul be maintained at a negative pressure of 0 J m of H 2 0(75Pa)
The high-bay area wul be the main experimental area where large engineering experiments wifl be performed Experiments wnl involve circulating mohen mixtures of LiF-neFj-ThF4 lithium chloride and molten Bi-Li alloys The experiments wffl also use elemental fluorine hydrogen fluoride hydrogen chloride and hydrogen gases as reactants and wnl use purified argon for purgshying Excess fluorine hydrogen fluoride and hydrogen chloride wil be neutralized in a caustic scrubber using KOH solutions and the cleaned and filtered off-gas win be ducted to a bunding exhaust system The experishymental equipment and components wil be housed in steel cubicles with floor pans which can contain any salt spJO The cumdes wnl be maintained at a negative presshysure with respect to the high-bay ambient The high-bay area can be supplied with up to 45000 cfm (212 msec) of air The air can be from recirculated inside
air laquo fresh ak from the outside The high-bay exhaust system wil be designed for 30jOOOcfm ( I 4 J msec)at floor level and 50000 cfn (236 msec) at the roof framing level A l exhaust ducts wnl contain fire barriers upstream from the double HEP A filter banks
The salt preparation and purification area wil consist of a 25-ft-wide by 3S-ft4ong by 14-ft-hJgh (76 X 107 X 4J m) raw materials storage room a 22 X 22 X 28-ft-high (67 X 67 X 8J m) room for weighing and blending the salt constituents and a 40-ft-wide by 45-ft-loug by 28-ft-high (122 X 137 X 85 m) room for melting rk-HF treating and filtering the fluoride salt mixtures This facility should be capable of producing I6j000 kg per year of fluoride salt mixtures using the batch processing method in use at the (acuity at Y-12
The estimated cost for the FPEC is SI 5000000 of which $5200000 provides for inflation during the three years required for design and construction of the baking
The design is essentially complete and the conceptual design report is scheduled to be issued in September 1975 Authorization for this project will be proposed for FY 1978
Part 5 Salt Production
9- Production of Fluoride Sak Mixtures I
F L Daley
A salt production facility is operated by the Fluoride Salt Production Group for preparation of salt mixtures required by experimenters in the MSR Program The group is responsible for blending purifying and packshyaging salt of the required compositions
Much of the salt produced is used in studies on Hast el -loy N development in which the concentrations of metal fluorides particularly nickelironand chromium are important study parameters Ic is thus desirable to use salt in which the concentrations of these metal fluorides are low and also reproducible from one salt batch to the next Oxides are undesirable salt contamishynants primarily because of the adverse effect of uranium precipitation and also because of the effect of oxides on corrosion behavior of the salt Sulfur is another conshytaminant present in the raw materials used for preparing salt mixtures Sulfur is quite destructive to nickel-based alloys at temperatures above 350degC because a nckel -nickel sulfide eutectic which melts at about 645degC penetrates the grain boundaries and leads tc inlergrlaquonu-lar attack of the metal The maximum desired ievels for these contaminants in the fluoride salt mixtures are iron 50 ppm chromium 25 ppm nickel 20 ppmsulshyfur lt5 ppm oxygen lt30 ppm Other duties of the group include procurement of raw materials construcshytion and installation of processing equipment and reshyfinement of process operating methods based on results from operation of the production facility
When the facility was reactivated during 1974 initial production was carried out in existing small-scale (8-in-
bullConMiliam
r MSR Program Research and Development
RWttorton
diam) reactors while new large-scale (I2-in-diam) reacshytors were eing installed Experience with both the small and laige units is summarized in the remainder of this chapter
91 QUANTITIES OF SALT PRODUCED
The 3-in-diam reactor was used for production from startup of the program in early 1974 through the first three months of 1975 During this period a total of nine full-scale batches (315 kg total) were processed and made available to investigators Salt from the nine batches was shipped in a total of 2i containers of apshypropriate sizes In general operation of the 8-in-diam reactor proceeded smoothly and the resulting salt was of acceptable composition and purity
Production in the 12-in-diam reactor was started in March 1975 Five production runs each involving about 150 kg of salt have been carried out Of the five salt batches processed four were suitable for use most of the salt from these four runs was used for fuel procshyessing experiments In contrast to the earlier runs in the 8-in -diam reactor difficulty has been observed in the 12-in-diam reactor with corrosion of dip lines in the meltdown vessel and with increasing concentrations of metallic impurities in the product salt
92 OPERATING EXPERIENCE IN l2-in-diani REACTOR
Operating data from the five production runs in the 12-in reactor are summarized in Table 91 Analyses of the resulting salt batches are given in Table 92 A description of the processing operations and conditions
164
TaMe9l ttoccMag fab derived fto to rave taae ami titntioa of iafci aad oatlet flows
Batch number (FS-)
Batch size
ltkgt
Total tarn Ihr)
HF in
(moles) in
(motes)
HF out
(molest
HF reacted (moles)
Dariag hydmlhoriaatiMi 101 150 125 1953 4253 1712 241 102 150 1025 2331 2738 2331 0 103 150 975 1808 2603 1419 389 104 150 95 2853 2473 2434 399 105 12 140 3752 2857 1877 1876
Batch number |FS-)
Batch size
Total time
Total H in
Total HF out
HF in otT-jraquos Imeq per liter of H) Batch
number |FS-) Ike) (hr) (moles) (moles) Start Finish
Daring hydrogen ledacliua
101 150 176 4725 0026 00018 00064 102 150 186 4995 0595 0100 0O50 103 150 244 6520 1560 0625 0016 104 150 440 12040 2180 0746 0008 105 112 320 8514 3290 0476 0102
Table 92 Aaatyxsof 1501 batches of LiF-BeF -ThF4 (72-16-12 mole )
prodaced in die 12-araquo learior
Batch number (FS-)
Analyses Batch
number (FS-) Li r)
Be Th F rlt)
Fe (ppni)
Cr (ppml
Ni (ppml
S (ppnw
O (ppm)
Nominal 72-1612 790 228 4411 4571
101 795 252 4392 4620 82 24 17 737 lt25 102 8 64 222 4200 4600 75 30 600 80 360 103 811 231 4327 4574 60 25 8 25 350 104 839 200 4381 4532 85 65 10 91 NO 105 1046 290 3435 5125 82r 25 8 576
prevailing during hydrofluorination and hydrogen reduction is given in the remainder of this section
921 Charging and Metting of Raw Materials
The salt produced in the l2-laquoi-diam reactor has been of the MSBR fuel carrier salt compostion (72-16-12 mcle LiF-BeFj-ThF4) production of salt of this composition will continue except that some batches will also contain 03 mole UF 4 If the production schedule permits an inventory of non-uranium-bearing salt will be accumulated before beginning the producshytion of uranium-bearing salt The LiF raw material for
the salt production facility is supplied by Y-12 as needed the BeF2 and ThF 4 are taken from raw mateshyrials that have been on hand for several years The only apparent effect of the long storage time on the raw materials is an increased moisture content of the BeF2
The production unit includes two l2-in-diam 72-in-high type 304 stainless steel vessels each of which is (Wed internally with a full-length open-top copper cylinder in which the salt is contained One vessel is used for batch melting of the raw material) which are charged to the meltdown vessel by gravity transfer through a 2-in-diam pipe the pipe extends into a weighing and charging room and is closed by a sealing
165
flange except during the loading operation The second unit the processing vessel is identical to the meltdown vessel except for the charging line Both vessels are fitted with dip lines for introducing gas to the bottom of the vessels for mixing or purifying a salt batch and both are connected to an off-gas system Each vessel is supported in a stainless steel liner and while in use is located in a heavy-duty electrical furnace The receiver vessel to which the salt product is transferred is 12 in in diameter 36 in high and is supported similarly in a furnace adjacent to the processing vessel furnace Salt transfer lines from the meltdown vessel to the procshyessing vessel and from the processing vessel to the reshyceiver are autoresistance heated via a 24-V power supply
The operational sequence includes salt charging meltshying and mixing in the meltdown vessel and transfer of the resulting salt to the processing vessel for purificashytion The process steps include hydrofluorirution hydrogen reduction and filtration during transfer of the purified salt from the processing vessel to the receiver vessel During both the hydrofluorination and hydrogen reduction steps the receiver and processing vessels are maintained at the same temperature and the process gases are passed through the receiver before being fed to the processing vessel in order to eliminate any oxide film on the interior of the receiver
The raw materials are loaded into the meltdown vessel by technicians wearing air suits having a supply of cooled fresh air The work is carried out in a small enclosed room in which containment is maintained by positive flow of air through the room to a bank of absolute filters The appropriate quantities of each of the raw materials are weighed and charged through a loading chute directly into the l2-in-diam melidown vessel which is at room temperature The larger lumps of BeF 2 and occasional lumps of LiF are broken by hand to facilitate loading and to provide improved mixshy
ing The ThF 4 is a fine powder which does not require six reduction The charging method leaves much to be desired melting would be more rapid and more predictshyable i f the particle size of the raw materials could be reduced and all components mixed well before they are charged to the meltdown vessel
Some of the more important impurities in the raw materials are listed in Table 9 3 The values shown are average values in most cases The metallic impurities are satisfactorily low however sulfur and possible silicon contribute to corrosion problems during melting of the raw matercls The moisture content of the raw mateshyrials is not shown but is an important parameter It is believed that hydrolysis of the fluorides during the initial heating period generates hydrofluoric add which subsequently reacts with sulfur- and silicon-containing compounds in the raw materials to form hydrogen sulshyfide and fluoroalidc add The quantities of these mateshyrials produced appear to be dependent on the temperashyture at which the meltdown vessel is held during the initial portion of the melting operation with 2 S proshyduction being most noticeable at temperatures above S00degC An addic compound which contains silicon and fluorine is evolved freely at lower temperatures in the 125 to 500degC range however the extent to which the material is corrosive to the meltdown vessel is not known Analytical data necessary to determine whether these low-temperature gases contain sulfur-bearing comshypounds are not available
The major effect of hydrogen sulfide on nickel comshyponents at temperatures in the rage 600 to 700degC is rapid eirbtlement of the nickel This action has resulted in breakage of dip legs in the meltdown vessel at the rate of one dip leg per run Breakage v observed to occur in the gas space above the melt and the broken dip leg falls to the bottom of the meltdown vessel where it is available for further attack by corrosive material) dissolved in the salt After melting batch
TaMe 93 Impr i t in tm raw material mtei ia ftmoriit a l t production (ppm)
Component S Si Fe Cr
Component Av Max A Max Av Max AVK Max
L i l 21 44 100 IllO 20 25 lt l lt l BeF 300 500 IHO I0O 50 100 20 40 rl ir- lt M 0 ltIO0 lt IO ltin 25 62 I I 17 Mixed raw
material^ ino 131 47 47 26 56 9 15
Mix ture required to produce tali havirfi compofll ion of 72-16-12 mole i I i l - B e l - I h i -
166
FS-101 was passed through a nickel filter having a mean pore size c f 40 i but plugging of the filter on subshysequent transfers led to its removal from the system Transfers from the meltdown vessel are now made after allowing a period for particulate material to settle
A stainless steel dip leg was used in the meltdown vessel during the melting of batch FS-105 in an attempt to avoid cracking of the dip leg The use of stairJlaquolaquo steel was liter concluded to be unsuitable because of the increased concentrations of iron and chromium observed in the resulting salt product The dip leg did not embrittle nor break during melting of the salt but extensive corrosion was noted on the submerged porshytion of the leg As a result of these observations a dip leg of copper and nickel was constructed by placing a copper sheath over a heavy-waD nickel tube The nickel tube provides rigidity and the copper is used both outshyside and inside of the nickel tube to obtain resistance to corrosion The copper sheaths are welded together at the lower end of the dip leg located in the meltdown vessel This combination of materials is expected to result in an increased dip leg life and less contamination of the product salt
An error was made in charging the ThF4 for batch FS-105 which resulted in salt that did not have the desired composition
922 Hydrofluorination and Hydrogen Redaction
After a salt batch has been melted in the meltdown vessel it is transferred at a temperature of about 750degC to the processing vessel where it is sparged with an HF-Hj mixture at a temperature of about 625degC for a period of about 10 hr The salt is then sparged with H 2
at 700degC the H 2 flow rate of 10 std litersmin used during the hydrofluorination step is continued for 30 lltr to reduce iron and nickel fluorides to their raquoraquopective metals
Progress of the hydrofluorination step is monitored by determining the HF content of the HF-Hj inlet and exit gas streams by absorption and titration of the HF in a metered volume of exit gas When the HF concenshytration of the inlet and exit streams becomes equal (or the concentration in the exit stream becomes slightly higher than that in the inlet stream) contact of the salt with the HF-Hj mixture is stopped A relatively low temperature about I00degC above the salt liquidiu temshyperature is used to minimize the rate of corrosion of equipment and to maximize the rate at which oxides are hydrofluorinated The hydrofluorination step is folshylowed by treatment of the salt with hydrogen at 700degC
to reduce iron and nickel fluorides The utilization of hydrogen during this step is low and large volumes of H are required Since the reduction reaction releases HF the concentration of HF in the off-gas stream is monitored and hydrogen treatment is stopped when the HF concentration reaches a low value (about 002 meqliter) and remains constant within the detection limits of the titration method
The total gas flows (H 2 and HF)during the processing operations are shown in Table 91 The values in the table reflect a steadily increasing quantity (from FS-101 to FS-105) of HF generated by H2 reduction of metallic fluorides that can be ascribed to a buildup of metals (largely iron and mcke) in the salt heels in the meltshydown vessel and in the processing vessel during operashytion These metals are converted to fluorides during hydrofluorination and thus add to the total quantity of metal fluoride to be reduced during hydrogen treatshyment
9 3 SUMMARY
The information presented in the previous sections indicates that the following factors are important in producing high-quality salt
1 Analyses of the raw materials indicate that there will be no concern with metallic contaminants unless metallic corrosion products are introduced during the salt purification or melting steps
2 The sequential buildup of metallic impurities in the salt produced in the I2-in-diam facility is the result of corrosion of the equipment This corrosion can be minimized by use of copper whenever possible when equipment is simultaneously exposed to salt and process gases Periodic hydrofluorination and discard of flush salt in the processing vessel should control any minor buildup of corrosion products
3 Although not demonstrated by data shown in this chapter it is believed that oxygen contamination can be held at low levels by maximizing the removal of moisture from the raw materials before they are melted and by improving control of the hydroshyfluorination process A method for measuring the H 0 produced by reaction of HF with oxides in the starting materials is being tested This should aid in determining the proper time at which to terminate contact of the salt with the HF-H2 mixture Alsoit may be necessary to determine the sulfur content of the off-gas since this may be the most difficult conshytaminant to remove from the salt
MOLTEN MLT REACTOR PROGRAM AUGUST lraquo4
i I MtfttitSI HHMHAM OIHH UgtM
m D M K M AMD M V I LOMMlaquo1 i n iH tGlL H
svsriMi AO AKAIVHI J N I N C U H
1 j A L L I N H
H 1 K | N lt I N
0 1 M A S M
0 I M I D N
ftWIMt A N C O f t M O M H T l M V I L O M N N I
m M G u laquo laquo O N H
A A H U - t U t l 1 M
W 0 H l V l M f t M N M 4 ft M l i l M H
m bull raquo | N S O N H 1 ftlOOLl N O t I R A V H I N M M bull H O raquo l raquo raquo S O N n
bull F A I M M O N M I M
4 M L V l l C L C M l M i S H V D i V t S i O N C M l W l t t N T D V I K O A j C M l W C A k F I C M A J O L O C J V 0 V gt V O V lt TACS A N D C A A W C S lgt iV traquo iC i M A C T O M ) O i V i S lt O N I X m v l f t S l T V O I I I N N t M I l
A t A H H I A U
M 1 M C O V MAC
M J U H U 0 Y N 1 T U W I I
H 1 I f c C O l MAC D N bull M lt S gt i MAC 1 M K h l S I A D MAC A k C L A J J I N C MAC I I J C X O U t t MAC
1 A U S T M A N G MAC
H l H I I I T A N t l MAC C A H V M A N M J laquo K t i t t H MAC
bull C U S U I MAC
bull M r N A M MAC 1 K R U C M I MAC A C t C M A f raquo M A U S ( H MAC i ft W O O t i S MAC
C M 4 M I C A L M K K I U 1 I M M A 1 I A I A L I
H M U I W V MAC
I I C H N I C A I t U W O I I t
A V HOI I M i MAC C 1 0 o N MAC n M raquo 4 H M t M - MAC 1 C k l l T N t H MAC J t I M i l H I H MAC I M l A r M l H L V MAC
J 1M H I N D I I C K S MAC T t M I N S O N MAC J 0 M ICWON - MAC
1 1 l A M H I X i 1 MAC
1 bullbull I I I MAC A ilaquo M i l l k H MAC (1 A gt 0 1 T1H MAC
I d H A H D O h MAC H H V I A M N O k MAC 1 i X M I M S K V H
tt I I S 1 I N I S MAC C K l i K l M A S MAC 1 H r H D I I I M MAC C A W A l l laquo ( l n 1 1 M K I C I H O I I S I MAC
M M gt H O C I t t l a O I V l l O r W I N I
J H Mt r HT ( )WraquoM IH bull
C M I M I C A l 0 I V I L 0 A M I N 1
A O fttk M l M S M H I I N M M
l O l N l l f t l laquo a O I V l l O H H N 1
gt H H I U H f O W I H JH C M SHOWN m n M c o i m c i c w t i bull H bull U N O A U l H M C S V A lt i
I B I A M S H O P A Y M
M M H C H I M I I T M V
l M M H H i S i A 1) r l L M I H S c L M A V A ( H t M t I C c raquo C A N T O N c I M l M c t O d i LPS T H I C K c raquo A r o i i raquo bull t H N M H O N k l U N t
D 1 H l A T H f R i V 1 O V A L l N l l N I c
A N A L Y T I C A L C H I M l t T N V
M M A A C H A f t O O I V I t O M M I N V
A I M f V I N AC H t A M | t bull AC B H C l A M K AC J M M A L I AC p L M A N N I N l t AC J P T f l U N t t AC
A N A l V S f l
i i I I M raquo I M At t it O o r t M - A l
ft ri i A i N t AC J A C A H I t l f AC
C O N S U L T A N T
r M A M A H t O V I I I
_ -L_ ULTMOOUCTION N M HtWIQN c bull I U A l t v C
bullH i AHVAK C I A c XJHNtOkt C t
U C 7 raquo -
CoMfKlMo
RMKMOO MMucrsiifii
LE
FENUAftY 1976
OAK RIDGE NATIONAL LABORATORY Oak R 4 T O T M H W 37W0
opwaNdby UNION CARMX CORPORATION
forffw ENERGY RESEARCH AND DEVELOPMENT ADMINISTRATION
MASTER V
~r -ruic rvVUMENT IS UNLIMITED WSTWBUTION OF THIS DucUWttrade ^
1 M Mpoct raquo olaquoc laquorf x laquornrraquo v4 IMA MIMA Weuro M C I MIO
i t a k trpoffe iHji AcwriM tnr ptoyrc bullgt the (aopun Ilihrgt c^wt i==v agt
0 laquo M 4 4 K M bMg 1 M V gt 31 Ilaquoraquo O K M - raquo tow (aMj CViltn 31 W ( K M X U total E M M J laquorgt 31 I OlaquoM raquo tow IKM laquolt gt-iraquo 0laquoM7raquo tonJtJMMfMgt3lllaquo5laquo ORMOSlaquo tnaikmtmtOctlt+tt HI (MSI m D m (tthnj teraquogt 3I JMI ii 30 |ltlaquo0 OKM-3QI4 tomJ fattMf Mgt 31 IlaquoMO ( K M 31 towi fawMf Frmgt gt Iltl OHM 321 lt towrftJMMf AMMM3I Ilaquoraquo OmSLi^Z total FMIMJ Hbrmay gt bull- ORM-334 tomt tJnf AMWlaquo 31Ilaquo ORM-34P to MOM Jmraquogt 311laquob3 0laquoL-35gt totaj tMJwf JMgt 31 IMJJ ORM-3raquogt towl EMM tani 31 fM O t M r rrd M Mgt 311laquoM OHM-3 I towJ to FVfrfwry 3gt bullbulllt OKM-sraquo total EMM laquo laquo i 31 Iltraquolt ORM-gt3b totaJ EMM F4MMgt gt IlaquoraquoM ORM-K~ to vlaquo MAM M J1Ilaquoferaquo G4LM4I J tow EMM i n laquo gt raquo I W OHM-raquobullraquo ftnud EarfMf Ailaquow4 3 bullraquo aM-raquolaquo4 toraquoi E M FlttNlaquoHgt i OHM4344 total EMJH Ktfmt 31 IltM OftM-ll towi EMJM FfMfgt gt Ilaquoraquoyenraquo ORM444 totaJEiMJ3llltraquo OfcM 444ft toml Eraquofc F4WlaquoM gt I OftM4j total b u b tmgmt 31 laquobull OftM467 feftal EMJM Flaquofcrmv bullraquo Ilaquo7l 0RM4gt total E n 31 I7| OftM47iC torn EMM Flaquoflaquoy -^ llaquoraquo OXM4K3 total EMM AapM 31 17 OftNL-5011 total EMM AMlt 31 I4 ORM-ttM towl E n FlaquoraMgt gt W
Coimnti
SUMAftY
PARTI mm KUCM Aim vcvujonmsj t v^SItMS AND ANALYSIS 2
raquo l n t t raquo bull ( bull bull laquo a Mete SJpound nam I I M 5 M C J U I M raquo 2 1 I r laquo 4 w t Srfl TlaquodMc4ap FMhn 3
I 2 amp w Rftowr raquo laquo sect bull 1 3 mroMi Aaalyws - 9
131 MSMSnrgt 9 l raquo TXr tCraquoo 12
14 t t^TcnpctsnMrDNpi I te fe 12
2 s m t J t S A X P C O I 0 9 ^ T S 0 m U gt r M L T 16 21 l t -Sgtnn TfdMofofy Fac 16
211 Crwraquomwiw4$rfihmdashySgttnOfcltjtiraquowi 16 2 12 S-ftowraquo^vfuiwHWif DWraquo3MCJamiilaquoirfVjnjWrnuwteimcraquogtn IS M M N ^ F laquo W M I F W 19 214 P w i mtmmiH 22
2 2 Claquo4aM-Sak T laquo f c raquo w F n iCSTFl 22 22 1 UvOMYJCM 22 2 2 M M M T M 23 223 TIMM Ei^tiMm 24
23 Ftwcrtf rlaquonlaquocimi Lon^sect 2 23 1 0prraquoiMigtfMSR-FCl-2raquo 26 231 DtwptmiCamnKnmafKVymtifCL 2
PART 2 IMLMSIRV
3 FUEL SALT CHEMISTRY 29 31 C n y i i i mttkt Lirtitmdashi Trfcinw Syami 29
3 Sprctrawoyy of Tcnprtan Sptctn n Manni Swu 30
3 3 Thr UrjMHMi TrirjIWori - H y d w y Ci|iiraquonmdashi m Matio Fhwnic SahMww 31
34 Fwam EJrctra S w laquo n laquo Mate Salts 32
35 Flaquo4 SafcladMi Sad lmnmttm Snafcn 34
36 Laiiior mamp FOWMHUH LJuMptcs of Fw-Ro TraMOc Meld Fbariafcs 37
ii i
IV
4 COOLANT SALT CHEMISTRY 4 4J ClKMtfiY ut SUAMW Ftourakcwa 41 4 2 CorrusmofStiuvinralAloysby Fmoroboraies 42
5 DEVELOPMENT ASD EVALUATION OF ANALYTICAL METHODS 44 51 m4aKAnafestraquo of Molten MSMtFnel 44 52 Tntmni A t f M Esperanents bull t Coutat-Salt Tedhnofagv Facnfcty 45 5J Ekctnlaquo^Kfic^Si^Maflralaquoll|aiMahaiLi -BeF -TM laquo
( T M 6 - i laquo ^ l 47 5 4 Vidummetnc Sankes of Tdnmnn m Molten LnT-BeF -ThT
lt2I6-I2 bull-gt 48
PAST 3 VUlERlAI^ DEVELOPMENT
6 DEVELOrMENT OF MODIFIED HASTELLOYN 52 61 DewelapinesM olt a Moitei Sait Test Fscdicy 52 62 rVocnmneai and Fabrication of Experjnental Almi 65
6-21 Production Heatsof 2 TiJIudrtied HasieRoy X 65 622 SltMfraquooictraquoltNi Keats of 2t TtModmcd H s N
Cammm Stdbmm 6raquo 6J WeMabiny afCanneTcni AlowgtModified HastetVn N 69 64 SUDdm of V m w Modified Hmrikn N Aloys m me
L nnf jdmed Condition 74 65 Mtdumcai Properties of Tiljmdashw Modified Hasietttn S Aloys
bull nW Umnndnied Condition 7 66 IVMirrsdnmn Creep Properties of Modified Kxuelloy N 82 6 7 Mkratntctwral Anah-raquos of Tnawm4lodified HastetVn N 84
671 MKroMracwnl Analysis of ABoy 503 and 114 85 672 HomopefctotisHastctoy S Aloys 88
6Jraquo Salt Corrosion Sindies 91 681 Flaquoe Silt Thermal Convection Lraquoraquops 93 682 Foci Soil Forced Circulation Loop 94 6 J raquo 3 CoolaMSalt Tfcennal ConvectionLoop 94
69 Corrosion of Hasaenm N and Otner Aloys m Steam 97 610 Observations of Reactions n M-talTeiliinum^i System 100 611 Operation of MetalTeHvnam-Salf Systems 101
6111 IHkumm Experimental put gtunVlt I 101 6112 Oironnnm Telunde Snfcmrfity Exprnmer 102 6113 Temjnwrt Experimental Pot Number 2 103
612 Gram tnawdary Embrittleinenl of Hasteiloy N by TeHuriwn 103 613 X-Ray Identification of Reaction Products of Hastetloy N
Exposed to Trikimm-CnnianMnit Eimromrents 107 614 MetaflografnW Exammatmo of Samples Exposed to
Telwnum-Canianwnii Environments 108 615 Examination of TeGcn-l P 119
6151 MeialopaphK Observations 123 6152 Chermcd Analyses for Temirium 124
V
fc16 Salt Prepantni aad Fad Fm Fafelaquo for TEGea-2 aad -3 131
7 FUEL PROCESSING MATERIALS DEVELOPMENT 132 71 SUCK CapMkTlaquob of Gfwhile with BoHMka^
bullKawm-Lrifcaaa SUMIMMK 132 7 2 Thermal Grlaquoaer Maraquo Transfer T laquo of Graph
maMofcMeaamLoap 133 T2I Wea^tChanan 133 722 Coaa^sttoaalCkaaats 133 f23 MkroMractwraiOnagri 137 7 24 DBcmsHN of Rente 37
PART 4 FUELPROCESSMC FOR MOLTEN-SALT REACTORS
a ENGINEERING DEVELOPMENT OF PROCESSING OPERATIONS 142 HI Metal TransferProcessDevelopment 142
111 Addrtion ltM Safe and turna Pka^ ir Metal Transfer Experanezi MTE 3R 143
12 R M d-l 144 a13 R raquo V 145 al 4 DrwwKM of Remits 145
a 2 Saftntoaiwir Contactor Dewdopmenr 147 H21 Lxpeirnents with a Mechanically Agitated Nnnitiprnwi Contactor
bull ike Sah-Ruamth Flowthronfi Facaify 14 a2 Evperiments with a Mrdumcafry Agrtatcd Vindiipri mi
omactor Una water and hVrcury 149 H3 Contavjoas Fhjonaator Devdopmert 152
a3 I histatbtion and Initial Operation of Autoresittance Heatmi Ten AHT4 152
a 3_ Drsam of aCoatamons Fuonaator Expenmeat Facdny iCFEFl 155 K33 Hmonme Disposal Sync for Md 7503 156 H4 Frozen WalCorrosion Protection Demonstration 156
a4 Fad Recnnstifation Enpneernt- Development 15 H41 Imtnaneniatton lor Anatynap Reaction Vessel Off-Gases 15a a42 Deng of the Second Fact Reconstitaoon Eapneermc
Experiment 160 85 Conceptual Deagn of a Mjlten-Salt Breeder Reactor Fad
Processing Engiaeermg Center 161
PART S SALT PRODUCTION
9 PRODUCTION OF FLUORIDE SALT MIXTURES FOR MSR PROGkAM RESEARCH AND DEVELOPMENT 163 91 Quantifies of Salt f-rodaced 163 92 Operating Experience in l2-m-diam Reactor 163
921 Charging and Mrfimg ltA Raw Materials 164 922 Hydrofluorination and Hydrogen Reduction 166
93 Summary 166
ORGANIZATION OIART - 167
PAST I h B M D E 5 raquo r a AND DEVELOPMENT
J REnael
I Srsvcavaad AmJrait
CaVnaatnms c4 the expected trnmm tcknor in refoessce-deagn MSMt a m loatmuid wall stmVcs of the uoanbte effects of ovale rams on heat ex chaff surfaces in the steam system and on surfaces exposed to the ccmaimmtm atmutawew The presence of oxide A n vjnraquoH laquoery km ptimubmty on the heat toaster surfaces would SMstnVaaey reduce the rate of intmm nwgrgrion to the steam system became of the mciemmg importance laquoltf the oxide-Am resistance at very km parshytial pre a w i of hydrogen and irnnaa l lowexi the reduction irom this effect alone would be rnuufficieut to heat rbe rate of tritiuui msginion to the steam system t J denied tames At rates ltd tritium irans-pori le the steam system the presence of oxuk-fam rcastatccs ltm loop wait tends to mcrease the rate of frinsra Hem mto the steam However tins effect a mukpufkaat at the low migiatiiw rates required
Potential ^inbwuonj of tritium m the ruotmt-Snh Technology Facmty were estimated for the cundrtmus o planned expenments In the absence of inborn rater-^ctioe with the salt other than mnpk ihisututici as ranch as laquoW5 of the added tnthaa cowU be expected to escape through the loop wals Removal of significant fractions in the loop off-fas coaM he expected uaH i the effective permeabmty of the loop watts were 10 to 100 times less than that of bare metal
Substantial chemical interaction of tritium with Nnaf 4-NaF was observed in the two tritium addition tests performed Ratios of cornbmrd-to-efcmnilal tritshyium in the salt inferred from elemental concentrations in the off-fas and combined concentrations m the sail were 50 and 530 for the two tests Approximately pound to of the dded tritium was removed in the off-gas stream prindpaly in a chermcaay combined water-soluble form
An undated aeutromes modrl raquot the lOOv-Mtftci releteace-dcsam MSMt r heme developed Muhi-duneanuaat mntagioap cakwUtmas wdi me the VENshyTURE code with newt run crosfsectson data dented catNcK from the fcNDF-IV Wwantv Pruoriune bull the croavteefMW dau was completed tor 3 otJraquo nachdo at lorn temperatures gtJt mtemi lot the planard cakvb-i m v Crow-stetson dau are also heme exammed it the two-step thenaai reaction Nangtr lt Naij i lrf winch is expected ilaquoraquo be the principal to sxe ot hebum m MSMt stractaral metals
A review of i he dau and cakubtsuns medio estauatc tdtunwe mveutories m the TeGen-l experMKM m-catesanuaccTtamtgt ltbull Xr
Work raquo contmaHNj raquo the udgt bullgt thrruul rotvh-ettmg and creep fafaw m react vtrwctural nuternh Analytical ractbodS are bemg developed which wdl be apphed Ss reference-design MSMt ilaquogt evaluate the significance of these processes m HattePoy N
The (ins-Systems TechnoVigy racdtty was ilaquoperated with water throughout the report ptnod Efforts to reduce the annua um ltH the salt-pump shaft oscdbtiom have been unsuccessful The jmyunudt of these oscdb-tions rs brgety dependent upon vk laquoi w ed so a bger-dhmeter imprler which wnl give the design flow and head at kmer speeds rs heme fabneated A method was developed for estimating the pump fountain flow Smce this flow was higher than desirable bach vanes wtl be used on the new rmpener o bnui the How Tests made at the loop indicate that the densnometer can be used to determine bubMe-sepiralar efficiencies if short-term tests are used
Routine operation _ltf the (oobnt-Satt Technology Facility was esiaMrshrd with more than 50Ghrof sah circidation without plugging in the loop off-gas Nne Measurements of the amount ot salt mist in the off-gas stream showed 100 to 500 ngcm iSTP) depending on
VII
1 M
w
l t
I BLANK PAGE
bull-laquo-
laquo t u
the a l t temprrataK and the I F flow rale MMO ike loop gas space The M M trap awtaard m the sah cold trap was effectn m meanta ike pm^mg hraquot had been expeneaxd earner Two i m i a marcoon lesti bullere coadacteJia whjch 85 aad bullraquo cwTi teaarvtwds of ifitmed bydropea ere added to the loop dame two I04raquo periods- Ficqaeat n i l aad off-gas sample were takea to mumlor the tRtaaa bebamor m the kwp
The torcedltoarctwa loop MSat-FCL-2b has accw-rautatcd MOO hi of oneratnaa with MSMl reference hart vdi at deaf ^ r coadmoas wrm riW expected low O M -roaoa rates Dbu oMaawd oa the beat master ckarac-terufacs of das sak air being aaafvard The deaga B eaeaadK complete for torced-coawectioa loops FCL-3 aad FCL-4 Coaaaoaeats ate beaaj fabricated J dec-tncal a i i f lHwia is proccediag
PART 2 C V E M S n t Y
3 Fari-MtCfceaaMry
Refachch pare Li Te lahoat lt oa a mole haasi bullas piipaatd by the coatroaedaddrooaof Kaaraaa to Hiaad hdnum The lac tam was began at 15QT bat afciamefjr tempt Mimes greater thja 50tTC acre reshyquired to complete the reactwa LiTe was prepared by rcactmg the aoidaomrtric amounts of LijTe aad tcfa-raan f o r brat 550^0
Apparatus for the spectroscopic stady of letunam species ia MSMt far salt has beta aaeaawed rYeima-nar work am hnmaa teshmars ia cbkmde taehs has shown ant at least two Mfbi-abjurbaig spears are present wirh uwapoatuai at the raja Li-Te to UTe Farthenaorc stadia with T e ia LiO-KCI eatectic have shown that laquo addition to Telaquo a lecoad species is present at high lemperatewH aador lag habie km activity
Apanxtm for the qtearoihotometric stady of the conawriam UFlaquo(dgt bull 4H 2 iggt = UFidgt bull HF|graquo has beea assembled aaa measurements using LiineF as the sointnt haw begaa A prehaaaary valac of aboat 10 was obtaiacd for the eqiaktiiam quotient at 6S0degC Tins vaiae is ia good agreement with the valat obtained pnwoady by other workers
Detopmeni proceeded on porous aad pact d-bed electrode systems as coatiaaoas on-line moailors of conceatralioas of declroactiwt species in molten sail solutions The packed-bed electrode of glassy carbon spheres was caNbralaquo4d using Cd 1 ions in LiCI-Kfl eutectk before experiments were conducted with B ions in solution The results of the experiments demon-straied the cpabdity of the electrode for momioring these and other ions
Preunaaary eiftrraacar i n c conducted iraquo cvatiaic watt ^wntkKM fetatmg to the naxmg bullbulllaquo VaBr - jF coutaai sah with M S M tiid vdi D F - f k f - H i r 4 F tMfc-ll ~-0S mute I Ibe result showed that ihr rate of erutatjoa oi BF gas raquoa naxau was low Mi vac of sanf amounts m coolant vdi wtth fael tab Jal bulllaquo result at the purctpttatam M aramam- ltlaquoc ibiwaaa-coataaaac -antpuands Vlt data w^re abtaaed +m ibr aaxaa M sanfl aaamats ot farl salt wwh o4aM vW( HesahstHeiprraataiiMi whvh a satal amtaai ot on-l aat salt cuataaaay igtxale was aaed with tael salt sae-eraed d m oude speoes aawe stable dun I O wlaquotc pMseat smce bullgtraquo pitecipitjnua of I O was raquodraquosrtraquool
A stads ul laztice eadadaKs ot tirst-ruw traassfiua-atrial (Wndcs was aadertakea to proadr a theraquofciicjl basts laquobullraquo ii itll Haw thrnancbrnacal data Urn uraLiaial metal tlaondes bratg obtaated from mm4 eitctrcisie gjiiaaJL ceKs I igaadnrid comctamsto pkxsul lattKe emhapy laquos ttnaat aamber for the rwraquoraquo senes CaF laquoo laFz raquo ScFgt to GaF mdkaied that dte staadad embdptes at loranfua plusmntf gtol N jad V F weilaquo saostaclors bat dial a m accante expcraaeatal lamn of Sit fur T i F V F O F CrF F e f aad FeF woald be deswabh
Analysrs tlaquot raaplr i ot coaJeasate coarcted danat opnaiwa of the Cooba SJ Tccbaolagy Facigt nahcate that the mpur aboar the gtali B aot a taaie mokvafar coeapoaad bat rather a auxtarc ot stamk gateows species sach as H 0 HF aad K F The coadtn-sate dtowed a intmm coaceatratioa ratio of aboat 10 rentiwe to dar salt Tha resak tajatsts a pinablc method for coaccatrafiag aad collectiag tntiam -a aa MSMl Related work showed that NaBF0H dnnohed ia ^ltobal sah uadergoes a reactwn that redaccs the OH ~ coaceatratioa m the salt prodacmg a mbtde frac-tkm Phyacal aad chemical obstrtalioas were made on the sysem VaF-NaBF-BjO at 400 lo oOtfC Work with compoaikms typical of ibe usual coulaat salt (oxide coaceatratioas up to 1000 ppm| showed that at least two oxygea-ooataaaag species are present One species n N a raquo F raquo 0 the other has not yet been bulldenirfied
Slddtes were continued o determine the extent lo which borides were formed in Hbstetoy N and btcoael 600 by reaction with NaBFlaquo-NaF at 640degC Data obshytained thus far indicate some formation of chromium and nickel borides however after four months of exshyposure of the alloy samples lo sal the boride concentra lion on the metal surfaces did not exceed 500 ppm in
I X
Haste X and 1000 pom m hwoaci MM) The tcvdh jhraquo dtuwei that A n mdash i n n these laquobullgtbullgtgt was setec-incigt gtraquodued by rhe salt
IkMb thrv period I I ~ ratio were oMMoted by laquogt4taaMneirv lechnnnsrgt in imu rhetmai-cunvecSoa loop and ltAC oiced-circgtdaraquooa loop Subie redox mo dnom H4MIHK bullbull exist m tbmnal-convrctiou loops U A ) 2V the I I ut9raquo raquo approximately T A IO ani respectively In forced-cunvectampn wop H I - gt she I I rlaquoraquolaquo n about copy Vraquo meinpfs feme et Keen ante laquobullgt reoxuJur the I i fhe melt by the addition ot mchet tiuundelaquolaquo some other oxidant
The results rora the fast series of tntnuu ldditmn experiments at the ( raquo u b n - U i Tcdmulugy Facem ltholaquo (wraquo ten tattle mimm exist m the off-gas m the ctesnental state the bwtli of tbe tntruei ltvwi at i iuai-huved laquo water-Mi Ale K m h appears thai about W of the uuecttd inmm experienced tvawticanf holdup raquo thr salt -and was eveutualy remmed m the system ott-
It was observed that the Fe - Fe electrode reacshytion n molten LraquoF-leF-ThFlaquo lt~2-l6-l2 mok i ckfseH approximates the soluble product case at a guid electrode the inwduMc product case at pyroiytic graphshyite and- deptwdmg on the temperature both soluble and insoluble product cases at an indium ekxtrode
Yoffarmarirw measurement were node m muMen liF-nVF -fhF 4 toSowute jddrtiuru tit Li Te is an effort to identify soluble etevitoactive lehurium species re the melt No soitammetnc evidence of such comshypounds was ohtaated These observations were m general agreement with cherracal analysis that indicated lt5 ppm Tern the salt
fAKfi MATEMALSKVF4j0PMtIVT
u Dtncfupmvnl bull bull MMuinJ lunumvy 3
Work raquo parfnHy complete on the molten-salt test facrlrty to he used mostly for mechanical property testshying Much lt (he test equipment is oprralmn
Alt products except the seamless tubing of the V-Ti modified HasteHoy N were received The first heat weighed lOjOOO Ih and had a fairty narrow working lem-prrature range- The second heat weighed WOO lb and had a wider winking temperature range Seamless lubing is being fabricated by two venders WeMahility studies
on these two beats showed bat their urldnsg d u n e lettstacs were euuwahm to those ut standard Hatfefoy V and thai extstmg wetdng procedures ut standard HaMcwoy could he used fur the y Ti Audited
The mechanical properties of HasteBoy gt inuiiaed wwh ifUnMtm nwhrum aad aiunuMun were evahaied m the undated and uwrradnted MB These piupertjcs were umd to estunate tfae mdwudwd and courtuntd wOBceMtauans of Manwani muhwun and ahnuuHnn reouwed laquou produce bntrte mienueuBK phases The tomnuuu ot brstrk phases m the aloy n i t mdash n muwuni was enhanced by an apphed stxss
SpeciBMns ot modihed HnseSoy were exposed to idlunuw from several dMterewi sources Tbe partial pressure tH tewynum above CrTelaquo at TOO C sMtm reasoatfjty dose to that anttcaujied tor MSMb Metal-lugraphic e-umnitiua o tbe exposed specuuens aite strauwnt revealed iblaquo aftoss coniauung OS to I Nb were resttfant to neTgnnular craefcrng by teiurrum
Further aaatysn ot the data lrlaquown TeGen-l showed that most ot the tdunum m each fuel p s was coircen-tafed on the tube wall The concentration bullraquo the salt was I ppm gtrr less The salt bssbcen preparew igtit gtugtng the fuel pur m TeGen-r and- and the puu tor Telaquoelaquo-- base been assembled tlte tuhng
t ipenments were contused laquobull-gt evaluate graphite as a matenal tor fuel prlaquolaquocrsssng apphcaimus The peneira-tmn ot graphite by buRtuth-utbimn suiutnms was found tigt increase with mcreasmg lithium concentration of the stdutKm and pore diameter of the graphite Decreasing the pore dBrneter or the graohae by pitch impregnation decreased the average depth of penetration However because fhe structure of the graphite was sarobie greaier-fhan-average penetration occurred m reginns bullraquo low density
A thermal-convection loop construcied 01 irkdyb-denum conumed ATJ graphite specimens in hot- and cold-let reports and circulated Bt 24 wt bullbull 141 at t Li for WOO hr at 700 C maximum temperature with a temperature differential of I00degC Very large wetghr mcrextes tJO to tgtT~ cccurted in ail ot the graphite samples primarily as a result of bhmuth intrusion into the open piMouty ot fhe graphite Disamclar-metal mass transfer bet weep molybdenum and graphite was also noted These results and previous capsule test results suggest that fhe presence of mofyhdenum enhances intrusion of bifrnuth-lithium solutions into graphite Thin carbon layers were noted on the molybdenum
X
PART 4 FUEL PROCESSING FOR MOLTEN-SALT REACTORS
8 EsgMecfMg Dcvdopraest of Piocessiwg Operations
Addition of the salt and bismuth solutions to the process vessels in metal transfer experiment MTE-3B was completed Two experiments were performed to measure the removal rate and overall mass transfer olaquofficients of neodymium In the first run about 13 of the neodymium originally added to the fuel salt (72-16-12 mole UF-BeF2-ThF4) in the fuel-salt resershyvoir was removed durine the 100 hr of continuous operation Overall mass transfer coefficients for neoshydymium across the three salt-bismuth interfaces were lower 1ian predicted by literature correlations but were comparable to results seen in experiment MTE-3
For the first 60 hr of the second experiment which was a repeat of the first experiment the rate of removal of wodymium was similar The second run was termishynated because of unexpected entrainment of the fuel salt into the lithium chloride in the contactor which resulted in depletion of the lithium from the fh-Li solushytion in the stripper and stopped further neodymium transfer
Future experiments in MTE-3B will depend on detershymining the reason for the unexpected entrainment of fluoride salt into the lithium chloride and it will be necessary to remove and replace the lithium chloride that is presently contaminated with fluoride salt
A hydrodynamic run intended to determine the effect of increased agitator speed on the extent of entrainme w OIK phux uw tne other in the salt-bismuth conshytactor was performed No visual evidence of gross enshytrainment was found Analytical results indicate that the bismuth concentration in the fluoride salt phase decreased with increasing agitator speed This unshyexpected result is probably due to sample contaminashytion
Development work continued on an electrochemical technique for measuring electrolyte film mass transfer coefficients in a nondispersing mechanically agitated contactor using an aqueous electrolyte solution and mercury to simulate molten salt and bismuth During this report period experiments with Fe-Fe2 were nude with improved experimental apparatus A stanshydard calomel electrode which enables measurement of the mercury surface potential was obtained Electronic filters were attached to the inputs on the xy plotter to damp out noise in the signal to the plotter Near the end of the report period a potentiostat was obtained which will automate the scan procedure now performed with
the dc power supply Copper iron and gold anodes hjve been tested The gold anode is the most satisfacshytory choice since it does not react with the electrolyte solution By noting that the active anode area in the cell could be decreased with no resulting change in the difshyfusion current it was determined that the mercury cathode rather than the gold anode is polarized Results indicate that the ferric iron is being reduced by some contaminant in the system Further tests with purified mercury and electrolytes in the absence of oxygen indishycate that the contaminant was present in the mercury Analytical results for Fe and Fe1 concentrations in the electrolyte phase are inconsistent with expected results Qualitative results indicate that a buffered quinone-hydroquinone system may be usefid as an altershynate to the Fe-Fe2 system
Installation of autoresbtance heating test AHT-4 in which molten salt will be circulated through an autoresistance-heatelt test vessel in the presence of a frozen-salt fim was completed and operation was begun A conceptual design was made of a continuous fluorinator experimental facility for the demonstration of fluorination in a vessel protected by a frozen-salt film Design was completed and installation was begun on a fluorine disposal system in Building 7503 using a vertical scrubber laquoith a circulating KOH solution Inshystallation was completed of equipment to demonstiate the effectiveness of a frozen-salt film as protection against fluorine corrosion in a molten-salt system
Off-gas streams from the reaction vessels in the fuel reconstitution engineering experiments will be conshytinuously analyzed with Gow-Mac galaquo density detectors To determine whether hydrogen back-diffusion in the cell body will be a problem during the analysis of the HF-Hj mixture from th hydrogenation column the cell was calibrated with NJ-HJ mixtures It was found that when the reference gas flow rate to the cell is suffishyciently high i effect of hydrogen back-diffusion is not seen The second engineering experiment will be conducted in equipment which is either gold plated or gold lined to eliminate or minimize effects resulting from equipment corrosion Several alternatives for gold lining or gold plating are discussed The factors which must be considered in deciding between lining or plating are listed
A design is being prepared to define the scope estishymated design and construction costs method of accomshyplishment and schedules for a proposed Molten-Salt Breeder Reactor Fuel Processing Engineering Center The proposed building will provide space for preparashytion and purification of salt mixtures for engineering experincnts up to the scale required for a 1000-MWfe)
l
MSBR and for laboratories maintenance areas and offices The estimated cost of the facility is SI5000000 authorization will be proposed for FY 1978
PARTS SALT PRODUCTION
9 Prodactioaof Flwnde Salt Mixtures for Research and Development
Activities during the report period fall in three categories (I) salt production (2) facility and equipshy
ment maintenance and modification and (3) peripheral areas that indwb preparation of transfer vessels and assistance to others in equipment cleanup
Salt produced in this period totaling about 600 kg was delivered in more than 30 different containers About one-half of the salt was produced in an 8-in-diam purification vessel and had acceptable purity levels The remaining salt was produced in the 12-in-diam purification vessel during five runs each of which involved about I SO kg of salt
Part 1 MSBR Design and Development JREnge
The overall objective of MSBR design and developshyment activities is to evolve a conceptual design for an MSBR with adequately demonstrated performance safety and economic characteristics that will make it attractive for commercial power generation and to deshyvelop the associated reactor and safety technology reshyquired for the detailed design construction and operashytion of such a system Since it is likely that commercial systems will be preceded by one or more intermediate-scale test and demonstration reactors these activities include the conceptual design and technology developshyment associated with the intermediate systems
Although no system design work is in progress the ORNL reference conceptual design is being used as a basis to further evaluate the technical characteristics and performance of large molten-salt systems Calculashytions are being made to characterize the behavior nd distribution of tritium in a large system and to identify potential methods for limiting tritium release to the environment These analytic studies are closely correshylated with the experimental work in engineering-scae facilities Studies were started in this reporiing period to reexamine the expected behavior of xenon in an MSBR This work will ultimately use information from experiments in the Gas-Systems Technology Facilitiy (GSTF) to further refine l 5Xe-poisoning projections and to help define the requirements for MSBR core graphite
I Molfen-Salt Reactor Program Staff Conceptual Design Study of a Single-Fluid Molten-Salt Breeder Reactor ORNL-4541 (June 1971)
Additional core neutronics calculations are being made for the reference MSBR using widely accepted evaluated nuclear data and a two-dimensional computashytional model These calculations will provide updated estimates of the nuclear performance as well as add -tional information on core characteristics Analogous methods and data are employed to provide support for in-reactor irradiation work
The GSTF is an engineering-scale loop to be used in the development of gas injection and gas stripping techshynology for molten-salt systems and for the study of xenon and tritium behavior and heat transfer in MSBR fuel salt The faciiitiy is being operated with water to measure loop and pump characteristics that will be reshyquired for the performance and analysis of developshymental tests with fuel salt
The Coolant-Salt Technology Facility is being opershyated routinely to study processes involving the MSBR reference-design coolant salt NaBF4-NaF eutectic Tests are in progress to evaluate the distribution and behavior of tritium in this system
Candidate MSBR structural materials are exposed to fuel sail at reference-design temperatures and temperashyture differences (704degC maximum nd i 39 aC lt17) and representative salt velocities in forced-convection loops to evaluate corrosion effects under various chemical conditions These operations which are principally in support of the materials development effort also proshyvide experience in the operation of molten-salt systems and data on the physical and chemical characteristics of the salt One loop MSR-FCL-2b which is made of standard Hastelloy N is in routine operation two others to be made of titanium-modified Hastelloy N are under construction
1
m BLANK PAGE
L Systems JR
11 TRITIUM BEHAVIOR IN MOLTEN-SALT SYSTEMS
Studies to elucidate the behavior of tritium in large molten-salt systems were continued in this reporting period Additional calculations were made for the IOOO-MW(egt reference-design MSBR to examine the effects that an oxide film on metal surfaces might have on the distribution of tritium Analysis of the informashytion being generated by the tritium addition experishyments in the Coolant-Salt Technology Facility (CSTF) was begun As additional data and results are developed they will be incorporated into the MSBR studies
I l l MSBRCakvbtioas
G T Mays
Calculations were performed to examine the potential effects on tritium transport to the steam system caused by the formation of oxide films on the steam side of the tubes in the steam raising equipment of an MSBR Th rate of diffusion of hydrogen (tritium) through metal oxides typically is proportional to the firs power of the hydrogen partial pressure in the gas phase as opposed to the i power for diffusion through metals (i-e the diffusion process is molecular rather than atomic) In addition at moderate hydrogen partial pressures the permeabiiity coefficients of the oxides may be as low or lower than those of pure metals Thus at the very low hydrogen partial pressures that would be expected in an MSBR oxide films could offer substantial resistance to hydrogen (tritium) permeation However the efficiency of such films would be limited by the degree of metal surface coverage that could be established and mainshytained during operation of the system
The computational model1 for studying tritium behavior at steady state provides for variation of the metal permeability coefficients of the steam-system tubes but assumes that diffusion through the tube walls varies only with the A power of hydrogen partial presshysure Variations in metal permeability were considered in previously reported results However the model also includes the effect of a mass transfer coefficient for tritium transport through a salt film inside the tubes Since transport through the salt film depends upon the first power of tritium concentration (or partial presshysure) this value was used to estimate the effects of oxide films Effective mass transfer coefficients were
Analysts
computed which included the resistances of the oxide films as well as those of the salt films1
Tritium distribution calculations were made for a variety of situations in which it was assumed that the effective permeabilities of the oxide coatings in the steam system were I 10 10~2and 10~3 times those of the bare metal at a hydrogen partial pressure of I torr (130 Pa) These results were compared with cases without oxide coatings in which the permeabilities of the bare metal were reduced by factors of 110 I0 2 and I0 3 The comparisons were made at three values of the UUgt ratio (10 2 10 and 0 4 ) and in all cases sorption of hydrogen or HF on core graphite was asshysumed to be negligible
The results (Table il) indicate that a low-permeability oxide coating would be more effective than a low permeability in the metal itself for limiting tritium transport to the steam system When an oxide film resistance equal to that of the metal was added the rate of tritium transport to the steam system was apshyproximately halved as would be expected (The total resistance to tritium transport was not doubled because of the contribution from the salt film) The results with a factor of 10 reduction in a steam-tube permeability due to oxide formation indicate that tritium transport to the steam system could be limited to the design objective of 2 Ciday However it may be unreasonable to expect to obtain and maintain oxide films of this quality in an operating system
Additional calculations were performed to investigate the effect of reduced permeability of the primary and secondary loop walls through the formation of oxide coatings These coatings can be expected to form in a manner similar to those expected on the steam equipshyment For a given steam-tube permeability reducing the permeabilities of the loop walls would be expected to increase the amount of tritium transported to the steam system With the reduced loop-wall permeabilities less
1 R B Brig A Method for Ctlculalmr thr Steady Sute Distribution of Tritium in a Molten-Salt Bre jet Reactor Kant ORNL-TM-4804 raquoApril 197)
2 G T May in MSR fmgram Semiamtii Progr Rep Feh 2 1975 ORNL-5W7 pp3 12
3 Although ihri calculalional approach assume thai the oxide film i located inside the tubes rather than outside it can be shown that for given oxide and metal permeaMifie this irrangement slightly overestimate the rate of hydrogen permeashytion through the wall
3
TaMe t l Effect of oxide Wmdash on uitmm i todeamtrttmatm MSUtlaquo
Rjti of oxrior raquolaquolaquo laquobull H inlw ltlaquo meial permnbiliiy Imdash 1 tieaw iytteraquo lOday I io nominal metal ratio 0 i d film Redaced meial
prmKabriiiy mvae tlaquobetr prrambibiy4
1 I 0 811 142$ 1 10 J 656 1169 1 10 115 203
10 10= 173 1351 10 bull 10 138 114 10 bull 10 23 198
10 ltf 19 662 10 I 0 J 16 575 10 10 3 142
10 gt w 2 93 10 10 15 84 10 10 lt 31
No wrption of H or HF on core paphtte At a hydropen partial prewurc of I ion
rWith nomnul meul permeability ^No oxide film
tritium would permeate through the loop walk into the primary and secondary system containments eliminashyting a potential sink for tritium A higher tritium conshycentration for partial pressure) in the secondary system would result creating an increased driving force for tritium transport to the steam system
The result of the calculations did indicate that with out the presence of a chemical getter in the secondary coolant more tritium was transported to the steam system when the primary- and secondary-loop wall pershymeabilities were reduced than in the same cases with reference permeabilities for loop wads However more importantly for those cases where tritium transport to the steam system had been reduced to the design-timi abjective of 2 Ciday through chemical additions of H HF or a chemical getter results showed essentially no increase over the 2-Gday rate Thus it appears that reduced loop-wall permeability hat little effect on tritshyium transport for cases where a tritium exchange mateshyrial is present in the secondary coolant
1 1 9 f^^a^af ^dgt T^haMwaflV frMsawv
J R fcneH G T Mays
A 1000-MWe) MSBR is expected lo generate about 2420 Ci of tritium per full-power day Calculations showed4 that unless a major fraction of this tritium
were converted to a chemical form less mobde than elemental HT the rate of migration of tritium through the metal walk of heat exchange surfaces to the steam system could be unacceptaMy high The purpose of the tritium addition experiments in the CSTF is to simulate the general conditions in the MSBR coolant-salt system to determine the extent to which tritium can be held up in the NaBFlaquo-NaF salt There is evidence that hydrogen-containing compounds in the salt may retain significant amounts of tritium
In the experiments the first two in a planned series tritiated hydrogen was diffused into the circulating salt through the walls of a hollow HasteUoy N tube The tritium could accamuiaie in the salt pas into the off-gas system or permeate through the metal walk of the loop to the ventilated loop enclosure Tritium concenshytrations were monitored in the salt and in the loop off-gas In the firlaquo =o experiments 85 and 97 mCi of tritium diffused through the HasteHoy N injection tube For a detailed description of the experimental condishytions see Sect 22
The computer program5 for calculating the expected tritium distribution in a 1000-MW(e) MSBR was modishyfied to describe the CSTF and was used to calculate potential tritium distributions for the experiments under the following assumptions
1 steady-state conditions 2 only dissolution of elemental tritium (hydrogen) in
the salt with no chemicai reaction witn the salt or any of its components
3 all transport through metal walk varies as the power of hydrogen partial pressure
Calculations were made for addition rates o( tritiated hydrogen equivalent to those achieved in the CSTF exshyperiments using assumed loop-wail permeabilities rangshying from the value expected for bare metal to 10 of that value The results (Table 12) show a significant effect of loop wall permeabiity on the fraction of the added material that could escape through the wafts This table also shows the calculated steady-state concentrashytions of elemental tritium in the salt (nCig) and in the off-gas (pCicm) in the same units that are being wed in reporting experimentally observed conjurations Abo shown are the inventories of elemental tritium in the loop walk that would be associated with the calcushylated transport rates through the wafts Since these cal-
4 G T Mar- m MSB fhjpmm Semhwrnu Prop Hep Feb raquo I97S ORNL-5047 pp J 12
i Hraquo bullltbull ami C W N M j r A Method ft e CtkuUting Ihe Sternly Sime DtttrHmitut of Tritium m t Molten Saft Krrrdrr Kemcior Uml 0RNLTM-UO4 (April 19751
Table 12 Calculated rieady-Male tritium diitrrbuliorw InCSTF foe experimental addition rale
Additi on rate Loop wall Tt ilia ted permeability mixture (fraction of hydrogen Tritium bare-metal Kmraquohigt tmCihr) value)
3 1 79 1 10 10 bull 10 bull
3 3 C 93 io-laquo 10 bull 10raquo
Time to reach 8Sf of steady-
state conditions (hrl
Fraction of addition rale which permeate
loop w-y (it
elemental tril removal in oil
turn r1Hraquo
Klvntental tritium Time to reach
8Sf of steady-state conditions
(hrl
Fraction of addition rale which permeate
loop w-y (it
Iraction of addition rate removed
CD Concentration
tpCicmi
concent ration in tlaquolt traquocigi
03 994 06 400 13 95 771 229 I5IKMI 50
38 149 851 55000 200 42 16 984 64000 2211
03 994 06 5(HI 17 103 7$-raquo 243 I90IJ0 (gt4 37 143 HS7 fi7000 230 42 I S 9S5 77tMM 26tl
Irtiium inventory
in metal walk Kti
01 oK 16 17
013 10 19 20
Sail and oil-gas concentrations only longer times required for steady-slate permeation through loop walls
0I tritium in hydrogen
01 I l tritium in hydrogen
t
s
oriatmas represeai steady-state coadmoiaad the nt-naa additioa experaaeats iavolwr t raaskats it a asefal to cuaader the taae renaaed to reach the steady state At high loop-wal penaeabihiies the coaceatratioas of ekaMRtal bullrtraai m the salt aad off-gas are low aad lead to -each steady vataes qakfcry for die additioa rales (see Table 12)- Soaiewhai toager u
aied arith lower assaned loop-wal ptrmdashnbiam hi al cases iidinaiiialjr I n a y times are niaawd to reach steady-stale rates of tiitiaai release throa|h the loop walls However this has little effect oa the triturate steady-stole levels ia the sail aad off-gas
Figures II aad 12 show the resatts of intiwm cua-ceairatioa raeasareaMau v the salt aad off-gas from
are reqaired to reach the higher coaceatratiaas assoo- the CSTF dariag the first aad secoad irilian addition
tn a m - M B laquo raquo
lO _ I 1 - bull ~~l 1 1 1 1 1 1 1 ^ 5 mdash
O SALT llaquoC | )
bull 0raquoT-laquoAS WATER SOLUBLE t$CiJtmh
A 0FF-euroAS ELEMENTAL (aCiar)
1 Mil
2 bull f
bull0
_ 5 n
poundL_ bull0
_ 5 n
mdash
bull mdash
mdash J jy^TRITIUM ADOlTlON bull mdash
2 2 bull II mdash
oraquo II ^ 10 G c
i s
pound 2 z tal Z I O
bull
0
bull bull
bull
A
bull bull bull
IIIIIJ 1 1
s 0
0 mdash
0 mdash
I 5 s
2
10deg
mdashb bull
e
a
e O
A A
A A
I 5 s
2
10deg A A aaw
i bull bull
s
2
bull -
bull i mdash
in- i 15 17 1raquo 21 23 25 27 29 Si
JULY OATCttTS
Fjj II Ofctcfvclaquo4 tnttvui cottt9MnHtottinCSTF 9ttn I
5
2
5
2 mdash
9
u 2 mdash
H = -S bull o u S 3
2 -
^ raquo mdash
5 h
2
bull0deg
raquo
2
mdash 1 1 1 1 1 1 1 1 = ~ O SALT (laquoCi l mdash bull 0FF-6ASVATCR SOLUBLE fcOA-i5) ^ mdash A OFF-CAS ELEMENTAL (f Citw5) mdash
^mm
a ^^ mdash^ 1 ltlaquo bull raquo I 1 1 4
^^ mdash 1 1
1 4 ~ trade
I bull mdash
bull
bull bull
I bull
I bull mdash I bull mdash
=
U
KITH KM A DOtT ON _
= bull
bull bull
llllll 1 1 1 1 V
bull
mdash
bullr T 0 ^
laquo bull 1 A A ~bull r^^ i S 0 O mdash mdash i S
A A ~~
0 0
e
51 A o = ^v 1 M M
mdash 4 A o-
mdash 1 -
bullbull i
T t If traquo bullraquo OATC MJtutT laquof7raquo
IT laquot 21
bull M M M ti cvrr MM i
7
tests The concentrations reported for the salt represent tritium in a chemically combined form since any eleshymental IfT trapped in the samples would have been reshyleased in preparing them for scintillation counting The tritium in the off-gis was present in two distinctly difshyferent cheriksl fonrr Part of the tritium activity was present in a water-soluble form implying a chemkil compound since HT does not interact significantly with water at room temperature The other form is presumed to be elemental HT since ft was trapped in water after passage of the sample stream through a bed of hot CuO
In all cases the results are presented in Figs 11 and 12 as reported with no corrections for apparent baseshyline concentrations However the results of samples taken before and after each test suggest that nonzero baseline concentrations were present The apparent baseline concentrations for the two experiments were
Itfexpcrineat Mcxatrineat
In uli 17 nCig I nCig In olT-cas elemental I pCicm1 I pOcm In off-jta water oiuMe I pCicm3 50 pCiere
During the tritium addition period for the first experishyment the tritium concentration in the salt (Fig I I open circles) increased almost linearly to a maximum of about 100 nCig and then decreased approximately exponentially over the following 3 to 4 days to its preshytest baseline concentration In the second experiment (Fig 12 open circles) the tritium concentration in the salt reached a maximum of 70 nCig and returned to the baseline concentration about 6 to 7 days later If baseshyline corrections are applied to the salt-sample data the apparent half-lives for tritium removal from the salt for the two experiments ar 92 and 12 hr respectively
If tritium removal from the salt is assumed to be a pure first-order process or combination of such procshyesses and if it is assumed that the processes were also active during the addition period the buildup of the tritium inventory in the salt (for a constant addition rate)should be described by
J M I O - i l l - bull ) X
where
V() tritium inventory in salt at any time I during che addition
A tritium addition rate
A lime constant for the removal process (or proc-esats)
I f several first-order processes were involved bull the intshyrant removal from the salt the time constant X would be the sum of the several individual time constants but the individual values would not be identifiable Substishytution of the actual addition rate into this equation gives the expected tritium inventory in the salt at any lime i f all of the tritium were reacting with the salt Conversely substitution of observed inventory values permits evaluation of the effective addition rate (the rate at which tritium did react with the salt) In either case the results may be expressed as ritium trapping efficiencies with values of 85 and 50 respectively for the two experiments These trapping efficiencies imply that significant quantities of the added material were reacting with and being trapped (at least temponriy) by the salt Data from the second experiment suggest the presence of other mechanisms with significantly longer time constants for removal of tritium from the salt Because of the apparent scatter in the data at longer times the extraction of these time constants was not attempted
The water-soluble tritium in the off-gas during the first experiment (Fig 11 closed circles) did not inshycrease significantly until after the injection was comshypleted and then rose to 1750 pCicm 3 The level then dropped rapidly to about 50 pCicm 3 rose again to about 300 pCicm 1 6S days after the addition and then decreased to lower values In the second experishyment the water-soluble tritium in the off-gas rose rapshyidly during the addition period and reached a maximum value at the end of the addition of 13100 pCicm 3 Abo the ratio of the concentration of water-soluble tritium in the off-gas to that of the elemental form was substantially greater in the second experiment than in the first
Owing to the apparent scatter in the data involving the water-soluble tritium in the off-gas for the first exshyperiment no quantitative evaluation was attempted However in the second test the initial decrease in conshycentration has an apparent half-life of 18 hr but the data again suggest the presence of other time constants An attempt was made to separate the time constants by assuming that the decay curve was made up A two simple first-order exponentials This led to apparent half-km of 9 J and 37 hr for the two processes Numershyical integration of the water-soluble tritium data for the second experiment yielded a total flow of 58 mCi through the off-gas line during the removal period and 75 mCi during the addition period Thus a total of 65 mti or about 65 of the tritium added is accounted for as combined tritium in the off-gas stream during this test Since the concentration of elemental tritium was
8
always less than 001 of the combined tritium concenshytration the presence of any elemental tritium does not significantly affect this observation
The concentration of elemental tritium in the off-gas samples rose during the addition phase of each experishyment 2nd apparently began to decrease as soon as the addition was stopped The maximum concentration in the first test was about 800 pCicm3 and only 40 pCicmJ in the second In both cases the decrease in concentration with time after the addition was too irregular to justify any quantitative evaluation
Although no measure of elemental tritium concentrashytion in the oalt a available a value can be inferred from the concentration in the off-gas by (1) assuming that the elemental tritium in the off-gas samples represents release from the salt and only from the salt and (2) assigning reasonable values to gas stripping parameters in the CSTF pump tank Concentrations of eiementai tritium calculated in this way indicate that the ratios of combinedelemental tritium in the salt were about 50 and 530 in the first and second experiments respecshytively It appears that chemical interactions between the tritium-containitg compound in the off-gas and the new metal of the sample line may have been responsible for the high concentrations of eiementai tritium in he off-gas samples from the first test and that the actual ratio of combinedelemental tritium in the salt may have been higher than 50
The inferred maximum concentration of elemental tritium in the salt during the second experiment is about 013 nCig Extension of the calculated tritium distribution with nominal metal-wall permeability (Table 12) to lower concentrations indicates that at 013 nCig tritium permeation through the loop walls could account for no more than about one-third of the tritium added to the system Since this is close to the amount not accounted for in the off-gas samples it appears that the effective permeability of the loop walls is near that of bare metal
12 XENON BEHAVIOR IN THE MSBR
GTMays
The computer program MSRXEP Woden-tali Rate-tot Xenon Poisoning) describing the X e behavior in the reference-design MSBR was used to perform calculashytions to study the effects of the Knudsen diffusion coefshyficient for xenon in the bulk graphite and graphite coatshying of the reactor core on the X e poison fraction The program has been described previously bull7
Following the fission of the fuel the decay of the mass-135 fission fragments is assumed to follow the decav chain shown below
l l
5 X e (1529 mm)
135 s C i J 135
(659 hr) Ba
(30 X 10 yr) (stable)
This diagram illustrates the half-life of each isotope and the branching ratio of the 3 5 1 decaying to 5 m X e and l 3 5 X e assumed for this study Along with this decay chain the following input data were used
Bubble concentration 44 bubbles per cubic centimeter of salt
Total helium dissolved in salt and present in gas bubshybles 10 X 10 molecm3
Bubble separator efficiency 907
For these conditions the mass transfer correlation in the program gives a bubble mass transfer coefficient of 00166 cmsec which leads to a loop-averaged void fracshytion of 055 with an average bubble diameter of 065 mm The calculated 3 f Xe poison fraction is 00046
The reference Knudsen diffusion coefficients for the bulk graphite and graphite coating associated with the 00046 poison fraction are 238 X 10 and 258 X 10 cm2sec respectively The bulk graphite values were varied from 258 X 10 to 258 X 10 cm1sec assuming no graphite coating was present (Table 13 cases I 3 5 7) to observe the effect on the poison fraction The low-permeability graphite coaling - 028 mm thick was assigned bulk-graphite values for the Knudsen diffusion coefficient and porosity making the coating part of the bulk graphite for calculation purshyposes Under these conditions the porosity of the bulk graphite was held constant at a value about 31 times
bullThe complete units for diffusion coefficient arc (cm ps) (sec bull cm graphite)
6 H A McLain el al in MSR Pmgrmn Semttmu front Rep Aug 31 1972 ORNM832pp If 13
7 H A McLam et at in MSR fmpwm Stmiumu Prop Rep Feb 29 1972 ORNL-47K2 pp |3 16 17
9
Kmfara M i a s m cocflkatat l c raquo p v laquo c -en graphite) CakabKlaquo1 Xe
DOHOB fractna M k f r a p a i K Graphite coati
CakabKlaquo1 Xe DOHOB fractna
1 258 x 10 Socoanag 00153 2 258 x 10 258 x 10 bull O0J52
3 258 x 10 No CiOMg 00140 4 258 x 10 bull 258 x 10 7 00I4S
5 258 x 10 bull Nocoatne 00113 258 x 10 bull 258 x 10 00107
7 258 x 10 No coalBaj 00077 8 258 x to bull 258 x 10 c 00044
M t graphite porosity ralae RKMH COHSUHI in ail cam 31 t met greater than rhe valar for ike graphite coating Refereraquoce valar for Hrfk graphite r Reference laquoalac for graphite coanag forma fraction for reference case
greater than that of the graphite coating In addition the Knudsen diffusion coefficient for the graphite coatshying was varied within the same aforementioned range while the diffusion coefficient of the bulk graphite was held constant at its reference value oi 258 X 10 cm 2sec to observe the effects on the poison fraction (cases 2 4 6 81 The previously stated values involving bubble characteristics and mass transfer were held conshystant throughout this series oi cakulalions
The results (Table I J | indicate that Knudsen diffushysion coefficient for the bulk graphite and graphite coalshying at least as low as the reference values (258 X 10 and 258 X 10 cm 1 sec ie case 8) would be reshyquired to meet the 0005 target value I gtr the X e poison fraction A diffusion coefficient of less than 258 X 10 cm 2sec would be required for the bulk graphshyite with no coaling became of its higher porosity If the permeability of the graphite coating did not yield a difshyfusion coefficient equal to that of the reference value such a coating would have little effect ltgtn xenon poisonshying The penalty for not coaling ihe graphite iraquo about OX)I in xenon poison fraction or 001 in breeding ratio if no attempt is nude to decrease the permeability or porosity of ihe base material
It may be noted in case 3 that a slight reduction in the Knudsen diffusion coefficient for ihe bulk graphite is
more effective in reducing the 5 X e poison fraction than a simitar reduction in the Knudsen diffusion coeffishycient for the graphite coating in case 4 In cases 6 and 8 where the permeability of the coating is very low reshyducing the Knudstn diffusion coefficient for the graphshyite coating affects the 5 X e poison fraction much more strongly
1 3 NEUTRON ANALYSIS
H T Kerr D 1_ Reed E J Allen
The neutronic analysis work during this reporting period has involved several tasks aimed at additional description of the neutronic characteristics of an MSBR and the provision of ncutronics information for the fueled in-reactor irradiation experiments
I JI MSIX Studies
Neutronic analysis studies for the reference-design MSBR are in progress in three areas
1 development of a two-dimensional neutronic comshyputational model of the MSBR using the computer code VENTURE and reestablishing the operabiliiy of a reactor optimization code (RODI
2 updating the neutron cross-section data bast used by various computer programs
3 calculation of the rate at which helium wii be proshyduced in the reactor vessel of the MSBR
A neutronic computational model o( Ihe MSBR using the computer code VENshyTURE is being developed VENTURE is a multishydimensional multigroup neutron diffusion computer code The MSBR model will have nine neutron energy groups and the ir-z geometry shown in Fig I J The various zones in the model allow for different core comshypositions and cress-section sets In addition to providing a check oi the design studies made with the ROD code using one-dimensional calculations this model will pershymit explicit evaluation of the nuclear reactivity effects associated with localized core periurbatiuii ltch as limited core voiding Previously such effects were conshyservatively estimated from calculations for an infinite medium of salt and graphite
bullhr pneffcv tuuHaniial reducifcMt in da Kmudm aWuaioa owflfcieat probatory wouhl be accompjaml by reduced po-roaiy
I T B r- ter 0 R Voady and G W ( unnmfham III irTlKf A CoaV mock for Sotriig Htipaup Stummk-ProNtwt Applying the Finite-Difference DiffmkmPieorv Appnaimntkm to Seutron Trmnpprt ORNL-SOamp2 tOvtohet 175raquo
9 II r Ramnann el al HOD A Sudew (md Fuel Cycle ImfSt-Mi Code for CmuUlmtFuel Rewclon ORNL-TM-3JS9
l September I 711
10
79-m7S
-a r
a-7
PERCENT THICKNESS 1 cm) ZONE NO FUEL SALT RADIAL AXIAL
1 CONTROL ROOS 172 2195 2 CORE )A 132 32 a 2195 3 CORE I A 132 500 2195 4 CORE I B 132 1195 2195 5 CORE n A ANO B 370 381 254 bull 9lR)^bV ^ W ^ ^ V v 1000 51 51 7 GRAPHITE REFL 10 7S2 aio bull SALT ANNULUS 1000 oa oa 9 REACTOR VESSEL 51 51
Fk 1 J Tw MMMH^OMI coMf bulltMtoMiMoMorNsm
11
ROD is a computer prccram for nuclear and fuel-cycle analyses of circulating-fuel reactors It consists essenshytially of a neutronks subprogram an equuibrium-conceniration subprogram and an optimization subproshygram Variables uch as breeding ratio fuel composition etc can be optimized with respect to cost
The operational status of the ROD code has been reshyestablished by running a telaquo case for the reference-design IOOO-MW(e) MSBR using the old cross-section data previously generated for the MSR program The test case will be rerun using the ENDFB-IV cross secshytions and any significant differences will be evaluated and reported
Generation of bullposted cross section data The necesshysary descriptive information for the neutronic model for use in the computer code VENTURE has been colshylected and the most recent ENDF1 cross-section data are needed (The neutron cross-section data used for MSBR analysis were originally derived from the GAM-H and ENDFB-I libraries with some ORNL modificashytions1 and no recent updates have been made) The new cross-section data are being obtained exclusively from the ENDFB-IV data Tiles using the AMPX processing system This effort will provide evaluated cross-section data and neutron energy spectra for typical regions of an MSBR and will serve as the data base for subsequent MSBR nuclear analyses The steps involved in this process are
1 Calculate 123-neutron-energy-group cross sections from the ENDFB-IV library The ENDF point data for 39 nuclides are weighted over an assumed energy spectrum to derive mulfigroup cross sections Thermal scattering cross sections are treated at 300 600900 and 1200 K for each nudide
2 Determine contributions to the multgroup cross secshytions from resolved resonances resonance self-shielding is treated for the various fuel configurashytions at 900 K
3 Perform fuel-moderator cell calculations for four geometries to adjust the cross sections for the flux depressions in regions having a high concentration of fuel or moderator (ceD homogenization calculashytions)
10 ENDFB-IV is ihe Evaluated Nuclear Data File-Vcnion IV and is the national reference set of evaluated cross-section data
11 O L SmithPreparation of 123 Group Matter Ctwt Secshytion Library for MSR Calculation ORNL-TM-4066 (March 1973)
12 N M Crane et al AMPX A Modular Code System for Generating Coupled Muttipoup Neutron-Gamma Ubraries from ENDFIB ORNL-TM-3706 J1974)
4 Perform a one-dunemional neutron transport calcushylation of the MSBR core to determine 123-group spectra and collapse the 123-group cross-section set to nine groups for each of the various zones in the model
5 Reorder the nine-group set from nudide ordering to group ordering the cross sections are then ready for use in VENTURE and ROD
The initial processing step is capable of treating nuclides in groups of from 1 to 3 depending upon the amount of data in the ENDFB-IV file for each nuclide This step is now complete for aD the nuclides of interest except 2 T h
Heauaa production bull reactor vessel The helium proshyduction in the reactor vessel for the present reference design and possible alternate designs will be estimated in conjunction with the neutronic modeling of the MSBR (Neutron energy spectra and flux magnitudes in the reactor vessel as obtained from the neutronic modd provide the bass for calculating helium production rates)
Helium is produced in nickel-base alloys primarily from these reactions
raquoNi raquo gt raquoNi raquo gt 5 Fe + 4 He
N i ^ L _ raquo F e laquo H e
degNi gt i 7 F e r 4 H e
The sNi(njt)and the degNi(ija) reactions are induced only by high-energy neutrons whereas the 5Ni(n7raquo and 5 Ni(laquoa) reactions are induced primarily by low-energy neutrons In highly thermalized neutron energy spectra as in the MSBR vessd the two-step reaction 5Ni(n7) $Ni(ffa) is the principal source of helium The 5 Ni cross sections are not wdl known but differshyential measurements are being made by ENDF particishypants1 Abo hdium analyses are available from several irradiated nickd specimens and effective integral cross sections wii be derived from these data for comparisons with the measured cross sections
At presen some cross-section information is available for the NHHJO) reaction Values for the 2200-msec (ix 00253-eV) cross section have been reported as 137 barns 4 and 18 barns It has also been reshyported1 3 that a large resonance occurs at 2039 cV with a total width V of 139 eV From this information a preliminary estimate of the shape and magnitude oi the
13 F C ferry Report to the US Sutiear Data Committee ORNL-TM-4SS5 (April 1975)
14 H M Eibnd el al Hud Sri poundltty 5) I I January 1974
12
cross section can be deduced and 123-group cross secshytions generated
From the Breit-Wigner one-level formula
where
A = constant A = neutron energy
tr = resonance energy (2039 cV) = total width (139 eV)
The constant K can be determined from the value of the cross section at 00253 eV which for this study is assumed to be either 137 or 18 hams Energy-dependent cross sections can be generated and the helium production can then be estimated with te folshylowing equation
-V H eltraquolraquoraquoraquoilaquoraquoJ - bull bull )
X 1 - e x p ( - o e 0 1 o
- [I exp ( -OJ IDI OJ I
where o ( = (17) cross section of s Ni Oj = absorption cross section of s N i Oj = (na) cross section of N i A1 - initial s N i concentration
9 = neutron flux = time
V|| e(0 = helium concentration at time t
IJ2 Analysis of TeGenE-r-raquoiments
Fission rates and tellurium production rates for the fuel pins in the TeCen-l irradiation experiment were reported in the preceding MSR semiannual report The fission rates were estimated by a flux mapping experiment direct flux monitoring of the TeGen-l capshysule and computations analyses The tellurium concenshytrations in the fuel pins were calculated from these fisshysion rates but no estimates for the accuracy of the calculated tellurium concentrations were given in the report
The accuracy of the 2 3 U fission product yield data 1 6 leads to an estimated uncertainty for the yield of tellurium in the TeGen-l capsule of about 135 Assuming that the uncertainty in the estimated fission rates is plusmn15 the uncertainly in the reported tellurium concentrations is about 20
The TeGen-2 experimental capsule is scheduled to be inserted nto the ORR for irradiation in October I97S Flux monitors will be loaded into the capsule prior to the capsules insertion into the ORR After the TeGen-2 capsule is removed from the reactor the monitors will be recovered and their induced activities measured to develop estimates of the tellurium production rates for TeGen-2
14 HIGH-TEMPERATURE DESIGN METHODS
GTYahr
Thermal ratchetttng and creep-fatigue damage are important considerations in the structural design of high-temperature reactor systems Simplified analytical methods in ASME Code Case IS92 (ref 17) and RDT Standard F9-4T (ref 18) permit the assessment of ratchetting and creep-fatigue damage on the basis of elastic-analysis results provided 1 number of restrictive conditions are met Otherwise detailed inelastic analyshyses which are usually quite expensive for the conditions where they are currently necessary are required to show that code requirements are iet Analytical investishygations to extend the range over which simplified ratchshyetting and creep-fatigue rules may be used to show compliance with code requirements are being performed under the ORNL High-Temperature Structural Design Program which is supported in part by the MSRP Modeling procedures for applying the simplified ratchet-ting rules to geometries and loadings prototypic of those encountered in LMFBR component designs are to be identified Then trie conservative applicability of these ratcnetting rules and procedures and of elastic creep-fatigue rules will be demonstrated and placed on a reasonably sound and defensible engineering basis Finally an assessment will be made of the applicability of the simplified design methods to Hasteiloy N under MSBK design conditions and the importance of thermal ratchetling in an MSBR will be determined
S II T Kerr and F J Allen in MSR Program Semiannu Pnrfr Rep Feb A 1975 ORNL-5047pp M 15
16 M F Meek and B F Rider Compilation of Fission Product Yields Vallecilos Suclear Onter 1974 General Elec-ric Company NFDO-I2I54-I (January 26 1974)
17 Code Caw 1592 Interpretations of ASMF Boiler and Prejre Vessel Ctde American Society ltbull( Mechanical Fni-neerv New York 1974
18 KDT Standard F9-4T Requirements flt Construction of Suclear System Components at Elevated Temperatures (Suppleshyment to ASMF Code Cases I$92 1593 1594 1595 and I5VA) September 1974
13
The detailed plans for achieving the stated objectives were given in a previous progress report The basic approach is to perform a relatively small number of carefully planned and coordinated rigorous dastic-plastic-creep ratchetting-type analyses of the geometries illustrated in Fig 14 Each geometry is subjected to the axial bending thermal transient and pressure loadings described in Table 131 of ref 19 Structural problems I and 2 are being analyzed at ORNL using the PLACRE computer program 2 0 while problems 3 and 4 are being analyzed by Atomics International and Comshybustion Engineering respectively using the MARC comshyputer program1 Each inelastic analysis will include a complete code evaluation for accumulated strains and creep-fatigue damage Also ssociated with each inshy
elastic analysis are a number of elastic analyses to proshyvide the input parameters required to apply the various simplified ratchetting rules and procedures and elastic creep-fatigue noes The progress to date on these studies is discussed below
Both Al and CE have encountered difficulties in their three-dimensional inelastic analyses Although consider-
19 J M Comm and G T Yabr in MSR Program Semmtmu Progr Rep Feb 28 1975 ORNL-5047 pp 15-22
20 W K Saitory Fiirte Element Pnfnm Documentashytion High-Tempertnre Sintctmwl DrsnM Methods for LMFBR Components Quart Prop Rep Dec SI 1971 ORNL-TM-3736 p 66
21 MARC-CDC developed by MARC Analysis Research Corporation Providence Rl
-YV^ - NOTOCD CTLMMCM SHELLS TYPE 3 N0ZZLE-1D-9PHQMN
OftNl OWC 75 76S
SMELL
JUNCTION OETAS (TYPES 341
76i0 X ilaquo75 WML
TYPE 2- cnjomctL awns
Q-omdash -T-QlaquoO -Q0
) AT AT I (bull) STEPPED MMLTHKKNESS (k) UNFClaquoM WILL WTH
OFFERENTUL MTOCTTNG
TYPE 4- nomz-m-crurvmcM SHELL flHXMLET NOZZLE)
1 6 0 0 X0375 WALL
-TS IO X 1675 WALL
(O IMFODM VMU MTH (ABULT-M CYUNOEP AXIAL TEMPERATl J VWaATCN
Fij 14 Slnicturai crmfiguraiinns used in the analytical invatqplion of the applicability of simplified nlchetling and crrcp-faligiie rule
14
able effort has gone into developing fmite-elemeni models that are of a size that can be accommodated on presrnt-day computers and into improving the MARC computer program the large 3-D inelastic analyses are proving considerably more expensive to run than had been expected
The experience at AI and CE indicates the importance of developing amplified methods of analysis Three-dimensional inelastic analysis of many realistic comshyponent geometries is too expensive and time consuming at present to be used routinely Although developments in computers and stress analysis programs may bring the cost down in the future it is desirable meanwhile to mminuze die number of inelastic analyses that must be done
141 GrcutarCyundricai Shells
Nine cases of circular cylindrical shells luve been proshyposed for bulllaquo present study Two of the cases involve notched shells The other seven cases involve axial variashytions in temperature pressure andor wall thickness or a bunt-in wall All nine cases were to be analyzed using the ORNL in-house finite-element program PLACRE
A ten-cyde inelastic analysis and a one-cycle elastic analyras have now been completed for all nine cases Both thr inelastic and the elastic results for all nine cases have been completely poKprocessed
Because of modifications to the creep-fatigue damage rules presently under study by the ASME Boiler and Pressure Vessel Code Working Group on CreepFatigue it may be necessary to modify the ORNL postprocessor and repeal some of the postprocessing to keep the present study up to date
142 Nozzle-to-Spherical Sfcenf
After some difficulties the MARC computer code a operational on the IBM computer at the Rockwell Intershynational Western Computing Center and check cases have demonstrated that this code will perform satisfacshytorily
Considerable effort has gone into developing the finite-element model of the nozzle-to-sphcricai shell An isoparametric three-dimensional 20-node brick eleshyment will be used (o model the entire geometry Beshycause of symmetry about the plane of the applied moment only half of the nozzle-to-spherical shel has to be modeled There are raquoix 30deg-wide dements around
bullWork jlt ORNL by W K Sartory Work raquobull Atomics International by Y S Pn
the half-model There are three elements through the wall at the root section of the nozzle and only one element through the wall in both the nozzle and the sphere away from the intersection region
A series of elastic analyses must be done since this is a thermal stress problem in which temperature varies with time Since the moment applied to the nozzL is the only nonaxtsymmetric load the principle of supershyposition will be used to reduce the cost of the elastic analyses A series of axisymmetrk analyses were done to determine the stresses due to the internal pressure and temperature and one three-dimensional analysis was done to determine the stresses due to the moment applied to the nozzle The stresses from the three-dimensional analysis will be added to the stresses from the axisymmetric analyses to obtain the total elastic stresses
The axisymmetric model in the elastic analyses was used to determine what maximum thermal load increshyment may be employed without having to do an excesshysive number of iterations during each increment On this basis the first ryele of the three-dimensional inelastic analysis was divided into 32 increments The first three increments of the three-dimensional inelastic analysis have been completed The computer cost for these three increments was higher than anticipated Efforts wiQ be made to find some way to reduce the cost to an acceptshyable level
14J Nozzte-toCyindeT Intersection
The original concept for the inelastic ratchet ting-type analysis of the nozzle-to-cylinder intersection was to perform two separate analyses (I) a thin-shell analysis of the whole structure ami (2) a detailed three-dimensional solid analysis of the intersection only Disshyplacements and forces to be applied at the boundaries of the three-dimensional solid model of the intersection were to be determined from the shell model at the end of each loading increment The total computer time of the two analyses would be less than that required for the solution of the problem using one model of the complete nozzle-to-cylinder intersection with suffishyciently small elements in the intersection region Howshyever the transfer of the forces and deflections from the shell analysis to the three-dimensional solid analysis was found to be more difficult than anticipated Because the shell element and solid element have differtit displaceshyment functions a special constraint must be imposed on the shell elements at the boundaries of the three-dimensional solid model to assure compatibility This
bullWork at Combustion Engineering by R S Barsoum
15
stiffens the intersection in the shell model When runshyning the initial elastic analyses it was found that small changes in the displacement boundary conditions applied to the solid model would produce large changes in the results of the analysis- From a pragmatic viewshypoint the biggest difficulty with the two-model method is assuring that the correct data are transferred from the shell analysis to the solid analysis at every increment in loading
Due to the above considerations it was decided to do the analysis by using only one model made up of a combination of a reduced integration shell element and a 20-node solid element which are fully compatible with each other
It was necessary to restructure a large portion of the MARC program to perform the inelastic analysis for the
3-D nvdel of the nozzle-to-cylinder intersection This restructuring made a larger core available for the analyshys t The restructuring involved stripping unnccded porshytions of the program putting common space on low-cost storage and eliminating mesh optimization and its correspondence table
The inelastic analysis of the nozzle-to-cylinder intershysection was started The full pressure and nozzle-moment loadings were imposed on the structure which resulted in stresses less than 0936 of the yield stress at 870 K ( I 00degF) When the first increment of thermal load was applied convergence was not obtained because of an error in the computer program which is being corrected
2 Systems and Components Development R H Guymon
21 GASSYSTEMS TECHNOLOGY FACILITY
RHGugtmon GTMays
After a brief shutdown at the beginning of this repottshying period to modify running clearances in the pan water operation of the Gas-Systems Technology Faculty (GSTF) was resumed on March II 1975 with the bypass loop blanked (Fig 21 gt Considerably larger salt-pump shaft oscmatious were encountered than before the labyrinth clearances were increased1 After obtainshying calibration data for the main-loop variable-flow reshystricts and for the salt pump at low flows the ioor was shut down to install the bypass loop variable-flow re-slrictor Water testing was then resumed on April 14 and continued throughout the period
Data for calibration on the bypass loop variable-flow rcstrictor and for the salt pump were obtained At normal pump speed the head-capacity performance of the installed imprDer was v W below the nominal loop design conditions At the nominal liquid flow rate and pressure drop in the main loop the flow rates from the gas outlets of the bubble separator were satisfactory Although loop cavitation (as indicated by wise level) was reduced by replacing the variable-flow restrictors with orifices the amplitude of the salt-pump shaft oscilshylations was not reduced appreciably Prdirmnary infor-
I R H Gaymoa MJ V R Haadty JUSK ABVW Stmt-mm Anjr Rep Feb 291975 ORKL-507pp 23 25
shows that leakage past the salt-pump shaft labyrinth is higher than desirable and attempts wfti be made to reduce thts
Tests under actual operating conditions with water in the loop indicated that the densitometer war be sttsfac-tory for salt operation IVelinwuary information obshytained fiom saturating the loop water with air and then stripping the air by injecting hehum at the bubble genershyator indicated the need for moniioring the oxygen conshycentration in the off-gas from the bunt salt separator in the off-gas from the salt pump in the loop water and perhaps in the water in the pump tank Dtitkuhies were also encountered with the response lime of the oxygen monitors and with the reprodudbiity of their readings
Data on the salt-pump shaft deflections and oscara-tions obtained during the previous period indicated that the running clearances at the labyrinth (fountain flow area I and at the impeuer hub should be increased to prevent contact of the metal surfaces during operashytion with salt (Fig 22) After increasing the clearances water operation was restarted with the bypass loop Hanked off The shaft oscillations were much larger than they had been previously under similar conditions Turbulence or cavitation as indicated by noise was the apparent cause For more flexibility in (Renting condishytions the bypass-loop variable-flow restrictor was inshystalled Loop parameters were then recorded at many
cwmmo
Flaquoj 21 GB4VMWM Facaw
16
17
n$ J J csrf w raquoNVJgt
coaibinaiiotts of lalt-pump speed and settings of the mam loop and hypass4oop variable-flow lestriciorv
Lug-log plots were nude of pressure drops across various sections of the loop as functions of the flow rates through the segments Ssnce the head loss for a fixed resistance is proportional to a fixed power of the fluid velocity the cams should be straight lines unless the character of the resistance changes due to cavitashytion The pSots indicated that cavitation was occurring in the main loo between the inlet to the nauvloop variable-flow restricior f FE-l02A)and the throat oi the bubble generator at flow rates above 320 gpm (1200 liters mm I with the variable-flow resiriclor set at I in (25 mm I above 470 gpm with the variable-flow reslric-tor at 2 in (100 litersmin at 51 mml above 600 gpm with the variable-flow restricior at 3 in (2300 btersmin at 76 mml and above 630 gpm with the variable-flow resthctor at 4 in (2400 litersmin at 102 mml The data were not sufficiently precise to determine whether cavishytation was also occurring in the bypass loop however noise indicated thai it was
Since the loop turbulence andor cavitation as indishycated by noise and the salt-pump shaft escalations were unacceptable at conditions required by the bubble separator design changes were made in the main-loop and bypass-loop flow restrictions By replacing each vamMe-flow restrictor with two or more orifices in series the loop noise level was decreased but there was
little or no decrease in the aaphtwdr- of the a f t oscd-btions
The amptitaae of the shaft ascafetsoas was plotted as a wactiua of salt pump speed at various operating a laquo -dMMis (Fuj 23| At salt-pump speeds less than about 1600 rpm the oscantioas were reasonably smaM and ai any given speed appeared to be unaffected by (11 flow rates between 450 aad 1 0 ) gpmlt 1700 to 4000 liters n a n M 2 ) salt-pump overpre wares between 5 and iSpsig ( I J X 10 to 2D X 10 Pal ( 3 | type of restneuon (variaafc flow restnetors orifices or a coiahmaiion ot these I or 14) flow roate (through the main loop bypass loop or both) At higher speeds the osdaatioa ampit-twe mcreased rapidly with mcieasts in speed and there was mote scatter in the data making it difficult to evalshyuate improvement in cavitation and effects of other variables However at any given speed above about 1700 rpm mcreasmg the flow rate (between 450 and 1050gpm)caused larger oscanuoas
One puaablf explanation for the increased amplitude of the osculations at higher speeds b thai the shaft is approaching its critical vibration frequency and is theiraquo-fore more sensitive to disturbances such as loop turbushylence or carnation The critical speed of this impeller assembly is 220 rpm in an which would indicate a maximum normal operating speed of 1710 rpru using bullhe normal industrial practice ot operating pumps at less than 75^ of critical speed
If the pump shaft osculations were in fact a conshysequence of operation near the critical speed ot the rotating assembly two obvious alternatives were availshyable to reduce the amplitude of the oscuHaiions
1 further reduction of the loop disturbances to minishymize the driving forces that cause oscillation
2 operation at lower speeds to reduce the osolatorv response to disturbances
The first alternative was rejected because it would have required extensive modification of the loop and it was difficult to guarantee that all sources of such disturbshyances could be reduced to satisfactory levels Design cakidaiiofls showed that the desired flow and head (3800 litersmin at 3 0 3 m or 1000 gpm at 100 f u could be obtained by replacing the present 11 Virt-diam (2ftgtnun) impeter with a l3-tn-dam (330-mail unit and operating it at 1500 rpm A larger impeller is being machined from an available HastcHoy N rough casting Since the larger impeller will be somewhat heavier than the original one it win cause a reduction in the critical speed of the rotating assembly The estimated critical speed with the new impeller is 2000 rpm which makes the operating speed 757 of the critical speed
18
n-va
I
bull
bull 4SO-C4V laquo bull TOTM run
bull bull80-KM9 laquo bull TOTH FLOW bull t
bull bull
bull
bull bull bull bull bull bull
bull bull bull bull m bull m bull
r- i bull gt
bull bull bull bull - bull jr bullbull r laquo bull 1
bull laquooo ooo rsoo i4oo CMO
SALT n w SPCEO t fraquo) lt7oo laquoaoo
Flaquo2J GSTFpanpAtfia
At a few off-design conditions during some of the bter runs the pump shaft deflection records showed random spikes in one direction superimposed on the relatively uniform oscillations described earlier These occurred with higher than normal flow rates in the main loop or at reduced system overpressure Since eidter increasing the overpressure or injecting gas at the bubble generator reduced or eliminated these random oscillashytions it was concluded that they were a consequence of cavitation at the bubble generator Such cavitation and the attendant oscillations are not expected to occur at normal operating conditions
212 Sak-Twnw f i i f i inmdash u DMa and CaKbration of the Variable-Flow Ratricton
The original design of the CSTF provided for varying the salt-pump speed andor changing the variable-flow restrict or settings to obtain different flow rates or presshy
sures needed for future experiments However instrushymentation will not be provided for measuring the bypass-loop flow rate during salt operation and only urn salt pressure measuring devices will be installed I at the salt-pump discharge and at the bubble-separator disshycharge) Also since the salt pump was modified and has a mismatched impeller-volute combination no perforshymance data were available Therefore extra pressure indicators were installed for the water tests and loop pressure profiles were obtained at various pump speeds flow rales and variable-flow restricior settings to evalushyate the pump peiformance
The calibration of the main-loop variaMe-flow restric-tor and of the salt pump at low flow rales was straightshyforward since with the bypass loop blanked off the total pump flow was measured directly by the main-loop vert tun However once the bypass-loop variable-flow restrictor was installed the calibration of it and
19
the pump was complicated Hie main-loop variable-flow restriciof was closed and the bypass-loop variable-flow rest net or was calibrated at low flow laies using the pump calibration curves established before it was inshystalled The mam-loop variable-flow restrictor was then opened to various settings and the pump calibration curves were extended by adding the measured flow through the mam loop to the flow through the bypass loop taken from the bypass-loop variable-flow reslnctor calibration curves Then using these extended head-capaciiy curves for the pump it was possible to extend the calibration curves to higher flows
The pump calibration curves (Fig 241 indicate that at 1770 rpm the pump flow rate wiB be 970 gpm 13700 litersmm) at 100 ft 1305 ml of head The ongnul design called for 500 gpm (1900 litersmmgt through each loop however the bypass flow rate can be reduced to 470 gpm (1800 liters mm) without compromtsng any of the objectives
To determine the main-loop variable-flow restrictor selling for normal operation with a flow rale of 500 gpm in the mam loop plots were made of the pump head vs flow for several settings of the flew restrict or From these a curve was made of pump head at 500 gpm (1900 litersmm) vs settings (Fig 25) A 185-m (47-mm) setting wril give the desired head of 100 ft (305 m) at 500 gpm
m - K B i
lt M M laquolaquo IFC-I02M SCTTWG FOraquo 300 laquo bull Zr-MSS laquo bull C-laquo4AJ
SpoundTTlaquoVS FOM0laquoB ^ Str-MSS vlaquoMFt-laquoolaquoi
si TlaquoK ran 47olaquopraquo
1 2 3 4 VMIASLC FLOS EST^CTO SCTTI
s
FraquoZ5
bull40 bull n-vw
C O shy
CO
l
CO bull
40 1
20 f
o 200 400 M O n o ltooo woo FUMIlaquoOTI
Fit- bullbull Hcai capacity curves for oV GSTF y mdash gt bull
The bypass variable-flow reslnctor settings were detershymined similarly 7 -I found to be 1-85 in (47 mm) at 500 gpm (lltHXgt liters mm) or 170 in (43 mm) at 470 gpm (IK00 liter v mm)
21 J Satt-Pmnp Fountain Flow
The GSTF salt pump is a centrifugal sump pump having an impeller which rotates in a volute section which in turn is located in a pump bowl The clearance between the impeller and the volute assembly at the pump inlet allows leakage from the discharge directly (o the pump suction (see Fig 22) A second bypass flow called the fountain flow escapes through the clearances between the impeller shaft and the volute assembly This bypass stream flows into the pump bowl circulates downward and reenters the main stream at the pump suction Due to the large liquid holdup and large surface area in the pump bowl significant gas-liquid mass transshyfer can occur in the fountain flow stream and herefore its flow rale is important in analyzing mas transfer processes in the loop Since the fountain Pow is not measured directly a method using mass balances on
20
measured gas flows was developed to determute thn flow rale
A lump J-parameter mcjel of the GSTF was used to develop equations Iron which an express lor ike rounfam flow was dented The system model contain two major regions the pump bowl and the primary loop Imnn and bypass segmental cutmstmg ai a fas seciion and a liquid section tach section was assumed to be perfectly mued The three enteral time-dependent equations lor a specific p s m i gas mixture are given m Tabic 21 representing gas mas balances for the pumrbowi gas section the pump-bowl tinwd section and the primary-loop f seciwn Icuculating oidsraquo
These were simplified by applying the folowmg
1 There is no gas carry-under in the pump bowl which implies that Ugt the efficiency for separation of bobshybles from the fountain flow Ut a unity and Ft -Ffi bull | + Afs-gthe bwbWe surface area m the pump howl M I the void fraction in the pump bowl frgtngt and the concentration of gas m the pump bowl (Clt I are nonappbcable or zero
2 Mass transfer equtJibnurn nasts in the primary loop which implies that the mass transfer term - j(C 4 -KRTCi )a zero
3 Steady-stale conditions exist making all time derivashytives zero
4 Ff = 0 since there was no gas purge flow during the experiments
Therefore Eq (3) Table 21 reduces to
FB FfL ltlaquo = 0 Ml Solving f o r +
By adding Eqs (1) and (2) Table 21 and simplifying
FjyenLCgtFfi +1C+FBSCX
FC Ff( rtC1FBSCJ=0 16)
By substituting Eq (5) into Eq (6) Ff may be exshypressed in terms of a quadratic equation
ltC C 2 I F bull KQi Fbdquo FBSKCt C 2 )
FgCt FCtFf
QttlF8SltC C raquo F C | 0 (7gt
Equation (7) is a general solution for the fountain flow which depends upon the gas concentrations in
each ol the three sections of the model It it is assumed that man transfer equAbmm exists at the galaquoltiugtd interlace in the pump jowl the gas conceniciuon in the pump bowl liquid | ( I is relaied to the correspondmg concentration m the pump bowl gas section tCt I raquoy Henrys law If only one gas rs involved (eg heliumK C toNows directly from the pump buwl overpressure Further since mass transfer equuawium was assumed for the primary loop ihe gas ctmcentralion m the kiop liquid (for a smgk gas) ioifews from the loop average pressure and Henry s law Thus the foil am ikm magt be evahsalaquoed from fcq |7raquo using orker known liquid flow rates and measurable gas flow rales into and owl ol the system If no mass transfer is assumed to occm~ at the gas liquid mterface m the pump bowl thr gas conshycentration m the hqmd leaving the pump bowl is the same as thai in the cmtiiug liquid lue O = C I and Eq(7i reduces to
^=IFgCyFCi I ^
Since the rate oi mass transfer m the pump bond is neither minute nor zero Eq I 7 I ni l give a low indftca-tion and Eq (X| laquo i give a high indication of the founshytain flow rate The deviation from the actual fountain flow rate win depend on how much mass transfer actushyally occurs m any experimeni If the loop void fraction is increased (by increasing the gas input rate I the conshytribution of mass transfer across the gas-liquid interface to ihe flow rate of gas laquo-ji of the pump bowl wif be reduced relative to the bubble contribution Therefore a pkn of the calculated iountam flow vs Ihe reciprocal of the gas input rate at several different conditions should give the actual fountain flow rale when extrashypolated to zero (infinite gas flow rate) usmg either Eq (7raquoor(8gt
The preceding equations and approach were used to calculate the fountain How for the GSTF pump Results from ihe plot indicated thai the curves generated were not defined wen enough to provide accurately the reshyquired extrapolations The range of fountain flows at the highest gas input rate at which data were obtained was 100 to 200 gpm (30 to 760 litersmmraquo
Even the lower estimated value for the fountain flow may excessively complicate future mass transfer experishyments so efforts will be made to reduce this flow Since ihe labyrinth clearances cannot be reduced without incurring meial-io-metal contact between the pump shaft and the volute hack vanes will be installed on the lop of ihe impeller lo minimize the differential pressure which drives the fountain flow
Iihfc 21 (iiimiuhaUmimpjallnntfitf timtpulalfcinmiMHof (iVI
KllO til illlll|tkltil |tl pill|K lllllilllis scpHlUil IMIlaquo IfMIKU nl t in nl oil Kii iiivkiilnl ill llnw ill bull limn liiiiiilini bull iliraquoraquonluil |Mgt lt mw ^JVIIHIII pinup linlaquol III yis gt|iui Him lH|iil(lniv inliHir pump Imwl
lltpi l n I lt f lt bull bull bull laquo lt laquo laquo laquo raquo laquo iff
Kllgt ill tlltllllr lllgtMi|vraquoll bullMl itlsMllVCll IV 11111 lllllslll 111111 ILIIKUM lllraquoraquolaquogtlVlaquol |l ni ittN iimMim |HiMiii in pii-witi m ni ltlin|tiil ut ilimlraquoilaquol pivwiii in iligtlaquo ilhvilvcilin liKnimiiK liuinlim llutt limn IMlaquo A I raquo laquo IM in Iniltlil trnm pump innn| Iiwl ln|iml illaquo lnihlltKIIIIIII hi|iiiil initligt in |iiini|lt linul biwl in lu|i
IH (11 Imlt vill
laquoltplllln| Kpiitiui I bull(raquo bull raquo I US gt laquo A K U i IHIl gt raquobull raquol IyjM
raquo i
KiMniil ihmvn iluw nl ilntt nl hiililiUv n u n luinl t i IIIIIIIIIOMII iliMmUinl raquoM ImhNiivinuwit bull I Civ linnillnH igtilaquo in Itmi pump Imwl I IIISSIIMII IIUIIIIIH ill lninliin In IMIMIII
III limp mill IHIIIIIU bull Inlnnp bull (ligt bull IliMJo llim llnlaquo w p j u l m llflltLllnl l l l l n i i | i
l i p u i m i I bulllaquo bull gt laquo l laquo IKH gtill M raquo O 1 raquo
22
214 The void fraction of the liquid after it leaves the I
Me separator n u n be known in ordrr to evaluate the bubble separator efficiency Densitometer mstrumenta-IWB (unwf a digital voltmeter for readout was mrtalrd at the loop and tesu were uumr using 0 3 0 0 ( 1 1 X 0 z dnsecl i raquo T a ece The effccu of void fraction were shambled by inserting pontic sheets 3 and 6 nms |0J07copy and 0152 mmi thick between the
detector and by using the mrtamc shim side m m k n steel cahVratioa plates 10 to 250
mis (0254 to 6 J 5 mm) thick which were designed for rhraquo purpose
The nail cncounteied dming dealupmtnt testing uras stal peestnt The hourly drift would be equivalent to a
efficiency of shorn 10 a h operation (assuming a void fraction of 0J
at the - c ^^hMe separator) Thus short-term tesraquoi wnl be required to ntmnunt the bdbbk jcparaior efficiencies
bullused on densitometer readings the bubble-separator efficiency was greater than 98 at various operating conauuons with water whkh it shghtty predtcted
Ft Ft
Fraquos
Ft
A -
of liquid gar interface m pump bowl bubble surface area in puop bowl bubble surface area in loop gas concentration in pump bowl gas space gas concentration sn pumn bowl hauid gas concentration in the loop bubbles gas concentration in loop liquid gts concentration m pump bowl bubbles gas concentration in gas purge entering the pump bowl gas space flow of total off-fas from pump bowl gas fltow rate to bubble generator nqiad flow from bubble separator via the bum salt separator to the pump bowl (assume no bubshybles) fountain flow (liquid and buboto) flow of gas purge into pump bowl gas space flow of liquid and bubbles from pwnp bowl to loop mass transfer coefficient for gas dissolved in pump bowl liquid to gas space in pump bowl mass transfer coefficient for gas dissolved u pump bowl liquid to bubbles in pump bowl mass transfer coefficient for dissolved gas in loop liquid lo bubbles in loop liquid
K Henrys lr~ (solubility) coefficient Q flow of bruid and buttles to bubble separator A universal gas constant r temperature
V laquo total gas volume in pump bowl V2 mlumt of wquuland bubbles m pump bowl VL = volume of drcubnutt liquid and bubbles i
loop c ( bubble separator efficiency tf efficiency for separation of bubbles from founshy
tain Aow bull t z void fraction in loop fluid
ltbullgt void fraction m pump bowl flutd
2-2 COOLAKt-SALTnamOUXX FACaUTYKSfF)
A N Sunt
Modifications to the sak coM trap (SCT) were com 1 and the loop was started up on March 14 and operated for 1279 hr to check the effcetrve-|975
of the sail titer to obtain data on salt different operating condrtmws
off-gas sample dau m preparation Work was completed on design
and checkout of the trita the tritium test
generation rates and to obtain salt and for the tritium tests fabrication addition system started At the end of the report period two tritium additions had been completed aad plans were being made for additional tririum addition tests as well as tests designed to examine how the tritium behavior is affected by the infection of steam into the sail
221 Laap Opossum
The SCT flow tnes were disconnected from the sysshytem and the loop was started up on March I 1975 The loop operated continuously until May 6 1975 when it was shut down to permit insinuation of otnp-ment in the containment enclosure for the tritium tests The loop was started again on June 271975 and it was saB in operation at the end of the report period when more than 2500 hr of operating tune had been togged without pHajgmg in the off-gas tine This is convincing evidence that the salt nust filter has been effective since the off-gas Ime had piuggct after only 240 hr of operashytion before the nasi fdier was instated
The loop is operating at a pump speed of 1790 rpm (estimated salt flow rate 54 literssec) and a pump bowl
2 A N San MS 2$ 1975 OKNL-50t7t 25
J IMttI
Avar Rrp Frb
23
praquo overpressure ol 2hi X IU5 Pa (20G0 mm 1 absi The pump bowl oit-^u flow which consuls ui helium coniammg a tew percent of BF prm trace quantities ol condenuMe material is about 2 litervmm iSTPl- The BF i concentration ltraquoi the oil-gas rraquo a tuncnon ol the bull1-1 partial pressure in the tail which in lurn raquo a strong unction in the tail lemprfaiuie txcept Im short period raquoi lime when special tests required a different retime the valt circulating tempetature haraquo beet mauv lamcd ai 535 lo 540 ( at which pomt the BF concenshytration in she oli-ga dream is about 25r by volume The loop otf-garaquo stream emepf tor a 100-cm1 turn wmpk gti ream iv paued through a 72(cuht iraptdry ice alcohol bath | Material which is a dtn while toiid ai itap temperature and a dirty brawn ilmd upon warmshying to room temperaiuie and which is rich m tnimm (about 1(1 nO el continue ilaquogt collect m the cold trap at a rale laquogtt I igt lOngcm (STPlotKff-ga Thnmaie-iial rraquo believed lo be a variable mixture who- compos-lion depends on the relative partial pressures ol BF HFand H Ooser the salt (see Sect 41i
A ol 000 on Auguvt 31 Ilaquo75 the bullop had accushymulated 3073 hr ol sail circulating tune smce being reactivated in Decembei |raquo74
222 Salt Mat Test
Bemeen March 25 Ilaquoraquo75and April 24 Iraquo75 a series ot icsigt wj run lo determine ihe concent ration ot wit
t m the off-fas stream as a runctwu ot a l t tempera-lure aad BF flow for each lest the loop operating coadaioas were set at the desired values ami the off-fas stream was shunted through a metamc 5- to deg-m (iter whKh was inserted mto the ait-sample access nozzle on the pump howl The sal mat concentration was calcushylated usmg the fan m weight of the filler aad the total flow sf fas A total of tea teas were earned out The test tune was nnrmatty about 12 to 15 hi but in two cases it was shortened tc about 3 hr because at the buildup ot a high-preawiie drop acroa the fdter Pump bowl pressure was 2Jb7 X 10 Pa and total off-gas flow was 1 litervmm (STP| When BF was added to the helium entering the pump bowl the BF flow was ad-msted raquo (bat the BF partial pressure m the mcomuig gas was the same as tFe calculated psttial pressure of the BF over the salt asswmng the eutectic mixture ot NaBFlaquo acd aF The salt drcutatiag temperature was controlled at either 535 or 620degC The observed conshycern rations ol mtst m the off-gas (Table 22) ranged Irom MOO ng on ai the loner temperature ibdquo as mgh agt 500 ng cm 1 al the higher temperature At the lower temperature where the expected partial pressure of BF in the sail raquoalaquo low the addition of BF with the cover gas was ineffective m reducing the amount ot ~ist in the off-gas At the hajtter temperature Hugher BF
P 27
23 CSTTi 175
VJ St Bt rcmrvrjrurr ijpampr rtlaquoraquo
t gt prepare iraquom mmSTPgt bull mm tic
raquo
Sjir imit iltgtikrgturjiraquogtn IIK Jr o n laquorr if-jtni
2fraquo |ltraquoS
raquo 25laquogt
5
Ifco
Klt-tft Zgt
5 5-532
bulltnrrlaquoflr 4Vlt
H
ion
Avrufr laquoi
11 i KX
KvrisfX 15
Vtumi^r Ih niKviic bull HtipgtltJium
24
partial pressure in the salt) a significant reduction was observed in the mist concentration when i lFj was added with the cover gas However it was not reduced to as low a value as at the lower temperature These results whie not completely definitive suggest that bull F evolution from the salt may no be the only mrst-producing mechanism in the pump tank that is simple mechanical agitation of the salt in the pomp bowl may abo produce some mist In addition no data were obshytained with excess BFj concentrations m the cowr gas Since the mstaflatioR of the salt-rust iHter in the off gas line was effective in eiumnating the operational probshylems in the CSTF caused K v the mist further investigashytions of methods to lirnii or control the mist have been deferred m favor of experiments to study tritium beshyhavior in the system
The decision to use tritium rather than deuterium a a test gas4 in the CSTF necessitated additional design effort and a somewhat more elaborate test setup in order to satisfy apubcaMe radiation safety require-meats A conceptual design was prepared for he tritium addition system and a preimnnary radiation safety analysis was performed for the proposed test Engineershy
ing design procurement fabrication and msiaBauon of the tritium addition system were completed by the third week m June 1975- The addition tube and the addition procedure for tritium are essenttaly the same as those devised for the addition of deuterium The rwer tube of the addition assembly is pressurized with hydr-jgen contanung a small amount of tritium and the gas is avowed to diffuse through the Hastefloy N tube which loom the lower end of the addition tube and which is immersed in the flowing salt stream (see Fig 2oraquo The HasteSoy N lube is 120 mm long by 127 mm in OD by 106 mm m ID and provision p made to fasten metanurped specimens to the upstream faje The portion of the addition tube inunedntely adjacent to the HasteRoy N section is surrounded by an evacushyated annuius monitored to check for extraneous tritium leakage The hydrogen-tritium mixture is passed through a purifier (M-Ag tube) to remove impurities such u O Ngt and H G which might interfere with the permeation process The probe volume ~p (infecshytion tube plus adjacent tubing) and a calmrated refershyence volume are interconnected and pressurized with the H - T mixture at the start of the test The two volumes are then isolated trom each other whne the addition rs in progress At the end of the addition
-Owe 75-T2CW
TRITIUM TRANSFER CYLMOER
4 0 0 C
sect laquo r 2^
1 SAMPLE
VACUUM ltS)
ampQ- ]
HYDROGEN
VACUUM ANNULUS
INJECTION TU8E
|StT2
35-C
lOO-C
FLOW 532laquoCi
Fig 2 T w mdash aUthnm ygtw far CiSTF
25
period the difference m pressure between p and V is recorded then the two volumes are equdibrated and the final equilibrium pressure is recorded The initial and fwal pressures ir lppx and pz respectively the foul equilibrium pressure p and the known volume and temperature ot lgt are then used to calculate the amount ot fas which pernxated the addition probe according to the equation
laquogt PiPi Pi V bdquo = _ x ^ try Pzraquo PT
where n is (rK number oi moles ltgti gas transferred R is the molar gas constant Tr is the reference volume temshyperature and the other symbols are as previously deshyfined
During the addition the amount oi extraneous leakshyage i calculated from pressure rise measurements in the evacuated annulus and this quantity is subtracted trom n to obtain the net amount oi gas iransierred into ihe salt The tntium content ot the hydrogen-tritium mixshyture is determined by mass spectrometer anaksu and Ihe net amount ot added tritium is then caicuiated
Tritium land hydrogen) which enters the salt stream rs assumed either to rematR in the sail laquo iraquo leave ihe sail by one ot two paths eiiher hy permeation through the walls ltgtl ihe loop piping or by irartsler to the gas phase in ihe pump howl or in the sail monitoring vessel iSMYl and leaving the loop raquoih the oii-gas stream During and ailer ar addition the tritium conieni ot the sail is monshyitored b lakmg samples raquot salt trom ie sail pool n ihe pump bowl or in ihe SMV and ihe irmum content oi ihe oil-gas stream ts rrhMMored hv takiru sampics from he oii-gas line ai a point ahoul I m downstream bullgt ihe rramp bowl The oil-gas sample stream is pasted first through a water trap to collect chemicaiiy ^gtmh-neltl I water-slaquo M unlet tmium and then through an oxidizing atmosphere to convert eiemeniai iriiium io iniiaied water raquohkh is c-iliecled in a seciid irap The tritium conieni oi the salt samples and ltraquoi hoih ihlt oil-gas samples are determined hy a scintillation cHinimg techshynique During the iniiul tritium addition experiments no provision was made IlaquoH measuring loop wait petnva-lion so lhat ihe tritium lost hy this mechanism is assumed |o he Ihe ditferenlaquoe hefwven the arnouni of Iniiiim aided and ihe sum oi the quantities w-hich ieave in ihe oii-gas stream and which remain in the sail
firing the March 14 Igt~v | 4 y |ltrgt bdquopei almg period a number of sail and off-gas samples were taken fo obtain baseline raquoaJues |o minim concenira-lion and lo shake down and evaluate the sampling tech-ii-ities During sluiidown oi lthe CSTI- in Magt and June
Iraquo75 the intium addunn probe was msiaUed in the survediance-spei-onen access tube and the final installashytion work was done on the tnUum addition system A stainless steel valve (HV-255AI and some stainless steel tubing which were part of the original off-gas sample-line installation were removed and replaced with a Mood valve and Hastelloy N tubing because it was ieii that the Monti and HasteUoy N would be less likely to react with the off-gas sample stream Two 2-5-cm-diam X 45-cm-long KastelkA N lubes were filled with sail from the dram tank and set aside as representative samples oi the salt as it existed prior to the start oi the tntium tesis-
On June Z~ I~5 the mop was filled and salt cirvuia-tion was resumed Several additions o i hydrogen raquoere made to check out the operation of the addition system aid to obtan data on permtaiior rates A loul or bull J cm M f l oi hydrogen was added in ihese rest and the last addition lt raquol an STPraquo was made -gtn July Jfs Ilaquoraquo~5 with ihe addition tube pressuried to I_gt~ X It) Pa the measured permeation rale was about laquo cm hi ipared with a predicted value i raquo era hr The Iirsl addition o iriiium was made on July l~ i _ 5 and a second addition with CiHlditmns essenziaili he same as iraquor the fust additnm was made August 5 1 _ 5 In each case sail and oii-gas samples were taken during ihe tritium ad Inigtft lahoui 10 hri and or atgtraquou 2 weeks afterward until sample resuiis indicated Tf at the intium levels had returned io iheu pretest values or had Mahihed Oaia lot calculatufi o ch-e amount o addej ps are sin win in Tabic _ A maihemaiica analysis and discuss of ihe tampie results are presented in Se^ i i
TaMr 2J Jtwtmm JMIIPO 4U far CSTI rnf
f rr runilv-r 1 i lraquojrc ~ ~y s r
ti4iilaquon vijrTrJ i raquo bullxt ltMiri-n erxteJ - gt lt o -gti VMiTfcltn -aw bullgt t N bull Im-ijS p-i-uir^ TjiTa i s j r bull bull bull 1 raquoUl prcraquoMraquorf p~ ltti bullraquo laquo bull r - t |utftt -nm p-riu-r r f^i a bull laquobull 1 bull 1 r v-jirrlt- m i i gt i i
fr Tcmr^r 4u-r k bull laquo lt l l bullbull ltrr gt rv-Tltjriraquor - r m -raquo raquo i 1 bull bull raquolt--laquo-f i e j l -j -lt- rn bullbulllt raquo raquo 14
i--tTWjTl-raquon - J 7T1 bull - raquo bull bull gt |TTti-n -raquonltf n TilaquoT in nisfi ii bull bull bull
ra^ pr^i l--l i m u M e i laquo m i it it X bull bull
1 bullbull J irmm j dea bull ml 11 raquolt bull
26
2 J FORCEftCONVECTlON LOOPS
W R Huntley M D Silverman H fc Robertson
The Forced-Convection Corrosion Loop Program is part of the effort to develop a satisfactory structural alloy for molten-salt reactors Corrosion loop MSR-FCL-2b is operating with reference fuel salt at typical MSBR velocities and temperature gradients to evaluate the corrosion and mass transfer o( standard Kistelloy N Addition of tellurium to the salt in MSR-FCL-2b i olanned after baseline corrosion data ire obtained in me absence of tellurium At this time the loop has operated approximately 3000 hr at design ST conditions with the expected low corrosion rates
Two additional corrosion loop facilities designated -ISR-FCL 3 and MSR-FCL4 are being constructed They arc being fabricated of 2T titanium-modified Hastelloy N alloy which is expected to be more represhysentative of the final material of construction for an MSBR than standard Hastelloy N
2 JI Operation of MSR-FCL-2b
Loop FCL-2b was operated continuously for about 3000 hr from February to June lraquo75 unuer design ST (565degC minimum 70SdegC maximum)conditions During this period standard Hastelloy N corrosion specimens installed in the loop in January 1975 were exposed to circulating fuel salt at three different temperatures (565 635 and 705degC) As expected corrosion rates were low the highest value was 01 mil year Ojimyear) at the highest temperature station
Salt samples taken at intervals have been analyzed for major constituents metallic impurities and oxygen (Table 24) Except for an occasional high value for oxygen or iron the analyses are relatively consistent and indicate that the observed corrosion processes have had very little effect on the concentrations of the various species present in the fuel salt Analytical probe readings for the VIU ratio indicative of the redox condition of the salt have been taken on a weekly basis This ratio which wraquo about 7 X I0 3 at the beginning of the corrosion run rapidly dropped to about I X | 0 3
after the first 24 hr of operation The ratio then gradushyally fell to A I X I0 1 by the end of March CVI500 hr elapsed time) and it has remained at that level during the latter part of the operation
After the corrosion specimens were removed for the 3000-hr weight-change measurements preparations wei nude for obtaining htat transfer data on the Li-Be-Th-U fuel salt (717-16-12-93 mole ) At this
time a Calrod electric tubular heater failure was disshycovered on the pipe line (i 27-mm-OD X 11-aim-wall) which runs from metallurgical station No 3 to the inlet of cooler No I After removing the thermal insulation about 10 to 20 cm 3 of salt was found on the loop piping and the bumed-out heater Grainy material was present on the heater sheath at three locations directly opposite peeled-off sections of oxide layer on the Hastelloy N piping A small crack (A 5 mm long) was found on a tubing bend directly under the failed heater Whether the heater arced causing the piping to fail or whether the salt leak from the loop caused the healer burnout is uncertain at this time Examination of specishymens from these regions is continuing
The fuel salt was drained from the loop into the fill-and-drain tank after the leak was discovered Analytical results on a sample taken from the tank indicated that no obvious contamination of the fuel salt had occurred A new section oi tradeping was installed (approximately 24 m from metallurgical station No 3 to the inlet to cooler No I) During the shutdown several defective thermocouples and two defective dam-shell electric heaters were replaced Ball valves were refurbished numerous small repairs were made and instruments were recalibrated After the thermal insulation had heen replaced baseline heat loss measurements were made with no salt in the loop in preparation for taking heat transfer data The loop was ready for refilling at the end of aly approximately four weeks after the salt leak was discovered After filling the loop heat transfer measurements were obtained with flowing salt The ALPHA pump speed was varied from 1000 to 4600 rpm resulting in salt flows of approximately 27 to 16 litersmin which correspond to Reynolds numbers that vary from 1600 to 14000 The lower limit for salt flow was set to prevent freezing and the upper limit was dictated by the power required foi driving the pump At the lowest flow rate unusual wall temperature profiles were noted which probably were caused by entrance conditions and transitional flow effects The heat transshyfer measurements were completed near the end of this reporting period and analysis of the data is in progress
The stringers containing the Hastelloy N corrosion specimens were reinserted in the loop and ST operashytion (S65degC minimum 705degC maximum) was resumed in order to complete the originally planned 4000-hr corshyrosion run If no unusual corrosion behavior is encounshytered in the next 1000 hr of operation nickel fluoride (NiFj) additions will be made to the loop in order to raise the oxidation potential of the salt to a level correshysponding to a U^U3 ratio of about I0 3 and a new set of corrosion specimens will be exposed
27
raw t u si tioalaquolaquofcUF-laquofF -ThF-UFlaquo
i-im
Sanpfe Mo
Date impkd (197$)
Total hoars of a i l
arcabboa bullhel saatptcd
Major coapoMMs TIJCC ameiub Notes
Sanpfe Mo
Date impkd (197$)
Total hoars of a i l
arcabboa bullhel saatptcd Li Be Tb U F Fe a f t O C S
lb 1-17 0 78 221 43-2 I I I 467 101 40 23 lt50 I I 99 Flash salt 2b 1-23 48 60 42 52 3b 128 0 799 174 430 an 463 75 70 15 125 29 4 3 New sail 4b 2-11 177 137 63 60 75 Sb 2 18 355 154 64 68 45 6b 2-24 498 98 63 28 48 7b 3-3 676 7 8 236 4 2 J 105 463 147 67 35 45 23 17 bullb 3-25 1146 7UI 255 430 104 458 256 59 57 lt2S 14 9 9b 4 16 1647 816 229 432 097 452 $ 70 30 20 78 15
10b 5-12 2197 829 264 430 103 455 62 85 30 60 l i b 6 4 238 823 225 427 100 445 30 70 25 140 12b 6-23 3173 820 208 433 104 451 35 75 25 152 13b 7-3 3177 830 218 430 10 452 70 80 40 30 FaVaaa-dran
oak Mb 8-7 3246 728 203 454) 100 450 45 85 70 58
7|7-16-i2-03 mole bull
232 Desia Mid CoastnKtkm of FCL-3 raquossrfFCL4
The design work for FCL-3 and FCL-4 was essentially completed any changes or revisions which occur during construction of FCL-3 will also be made on FCL-4
The piping support frame for FCL-3 was installed and installation of electrical equipment is proceeding- Conshyduit lines have been fin from the variable-speed motor-generator set on the ground floor up to the electrical rack installed on the experiment floor and a sizable
number of transformers starters switches etc have been installed The instrument panel cabinets have been positioned and cable trays are now being installed Fabrication of two ALPHA-pump rotary elements and two pump bowls is 90 complete A large number of completed items for both loops (eg dump tanks auxilshyiary pump tanks cooler housings blower-duct assemshyblies electric drive motors purge gas cabinets etc-) are on hand awaiting installation Fabrication of the titanium-modified IrasteHoy N tubing for the salt piping of the loop is in progress
Pan 2 Chemistry
L M Ferris
Chemical research and devdopmen rdated to the design and ultima^ operation oraquo MSBKs are itill conshycentrated on fuel- and coolant-salt chemistry and the devdopment of analytical methods tV-r use in these systems-
Studies of the chemistry of tellurium in fuel salt have continued to aid in elucidating the role of this dement in the interranular cracking of Hascdioy N and related alloys An important initial phase of this work involves ihe preparation of the pure tellurides Li Te and LiTe3
for use in solubility measurements loop experiments clectroanaiytical studies and studies of tellurium redox behavior in molten salts Technique for preparing these idlurides have been developed and experimental quanshytities have been prepared Spectroscopic studies of tdlu-rium chemisfy in m-jlten salts and of the equilibrium H(ggt + UF 4 |d) = UKj(d) + HF(ggt have also been
initiated In work using molten chloride solvents at Lust tvo light-absorbing tellurium species have beei shown in be present These species are as yet unidentishyfied but have compositions in the range Li2Te to LiTe4 Preliminary values of the quotients for the above equilibrium have been obtained using LiBeF4 as the solvent These values are in reasonable agreement with those obtained previously by other workers
A packed-bed electrode of glassy carbon spheres was constructed calibrated with Cd1 ions and used in experiments with Hi1 ions in LiCI-KCI eutectic It was concluded that this electrode was prototypic of orie (hat could be used for the electroanalysis or electrolytic removal of bismuth oxide and other species in MSBR fuel salt Preliminary experiments were also conducted lo evaluate some questions relating raquoo the mixing of fuel
and coolant salts The results suggest ihat or mixing small amounts oV coolant salt with large amounts of fuel sal the rate of evolution of BFj gas will not be intolershyably high and that somj oxide can be present in the coolant salt without effecting precipitation of L0 or ThO - Lattice enthalpies of first-row transition metal fluorider were calculated to provide a theoretical basis for evaluating thermochemical data gtr svructural-metal fluorides
Work on several aspects of coolani-sait chemistry has continued Analyses of condensates from the Coolant-Salt Technology Facility (CSTF) indicate that the vapor above (he salt is a mixture of simple gases such as BFj HF and H 0 rather than a single molecular compound Tritium concentrates in the condensates by about a factor of 10 s relative to the salt Studies of the system NaF-NaBF 4-B 0 at 400 to 600degC show that at least two oxygen-containing species aie present in typical coolant salt One species is Na B F 6 0 j while the other has not yet belaquon identified
The development of analytical methods for both fuel and coolant salt was also continued An in-line voltam-metric method was used to monitor U^U 1 ratios in two thermal-convection and one forced-circulation loops Two additions of tritium were made at the CSTF The salt in the loop did significantly retain tritium and the tritium ultimately appeared in the off-gas Work was begun on using various electrodes for determining iron in MSBR fuel salt Previous work had been conducted with solvents that did not contain thorium Preliminary voltammetric experiments were conducted to identify soluble electroactive tellurium species in MSBR fuel salt
28
3L Fuc-J-Scik Chcmism
ADKeimers
31 COMPOUNDS IN THE LITHIUM-TELLURIUM SYSTEM
D Y Va^ntine A D Keimers
It has beei k-mcns rated that tellurium vapor can induce shallow grain-boundary attack in Hasiefloy N similar to that observed on the surfaces of the fuel-salt circuit of the MSRE However the actual oxidation state or states in which teilunum is present in MSBR fuel salt an LiF-BeF-ThF4-UFlaquo mixture and the chemical reactions with the Hastelloy N surfaces remain to be determined The lithium-tellurium system is being investigated to determine which Li-Te species can be present and to synthesize samples of all possible lithium tetlurides- The solubility of these compounds in the fuel salt will then be determined In addition they will be used in spectrophotometry- and electrochemical investishygations of tellurium species in melts
During this report period sample of LijTe and LiTe
were prepared The preparations were made in an argon-atmosphere vacuum box equipped with an enshyclosed evacuated heater which held a molybdenum crucible All handling of Li-Te compounds was done in inert-atmosphere boxes sometimes the compounds were sealed under vacuum to minimize oxygen nitroshygen or H 0 contamination Lithium having an oxygen content of ltI00 ppm was supplied by the Materials Compatibility Laboratory Metals 2nd Ceramics Divishysion Tellurium metal of 99999 wt Tr purity was obtained from Alpha Ventron Products
The Li2Te was first prepared by dropping small pieces of lithium into molten ellunum contained in a molybshydenum crucible at 550degC The reaction was extremely exothermic emitting fumes and light tlashes after each lithium addition Solid formation occurred at lower lithium concentrations than expected from the reported phase diagram2 Further lithium additions continued 10 be absorbed after first melting on the surface of the solid phase An amount of lithium necessary to satisfy Ihe Li2Tc si gtichiomeiry was taken up in this manner However because of the loss of vapor and of some solid material which splashed out of the crucible during the early additions of liihium it is doubtful that the stoichi-omclry was in fact preserved
The x-ray diffraction pattern showed a single phase identified as LijTc having a face-centered cubic strucshy
ture with a lattice parameter of 65119 t OJ0O0Z A J
The oxygen contamination in the product totaled about 375 ppm- Spectrographs analysis reported 0-5 wt ~ molybdenum present Since the oxygen level and moshylybdenum impurities were fairly low a larger-scale prepshyaration wts attempted as well as a direct preparation of LiTcj by the same method In both cases rv product was contaminated unacceptabiy with molybdenum and these preparations were discarded Apparently the first preparation had affected the surface of the crucible such that the reaction with molybdenum was accelershyated in these subsequent experiments
The molybdenum crucible was used for one further preparation after cleaning and polishing the inside surshyface The Li Te was prepared from the lithium-rich side of the phase diagram by dropping tellurium info molten lithium Since molybdenum is relatively inert toward lithium4 less reaction with the crucible was expected In addition this preparation could be made at a much lower temperature The tellurium was added to the lithium in small increments with the temperature held at 250degC Each of the first additions resulted in a smooth quiet reaction with a solid phase forming on the bottom of the crucible However since completion of the reaction was not visibly apparent the temperashyture of the system was increased above the tellurium melting point to about 550degC to ensure that unreacted tellurium was not on the bottom of the crucible More additions of tellurium were then made Above 500degC a popping noise was heard after each addition of tellushyrium After about three-fourths of the tellurium had besn added the system was mostly solid As more tellushyrium was added the amount of solid in the system became so great that further additions of tellurium were
I A D Keimers and D Y Valentin MSR Program Semi atmu Profr Rep f-eh ltlt 1975 ORNL-5047p 40
3 P T Cunningham S A Johnson and F i Cairns Vlectrmhem Soc Klrcirochrm Set Tech 120328(1973)
3 X-ray lattice parameters were measured by O B Cavin of the Metals and Ceramics Division The value 65119 00002 A measured tor IiTe is in agreement with the value 6SI7 A reported by K Ziml A Harden and B Dauth Hlektrochem 40 588 11934) The value 61620 bull 00002 A measured for LiTe is in agreement with the value 6162 A reported in ref 2
4 H W leavenworlh and R F CUaryAcu Mel 9519 11961)
29
30
not covered by the liquid Subsequent additions proshyduced light flashes and poppng associated with the highly exotherrmc reaction as encountered m the preshyvious preparations oi Li Te FuuBy enough additional tellurium was added to the sgt-stem to satisfy the Li Te stoictuonietry and the system was aflowed to cool to room temperature
Upon crushing the cooled product fow differently colored substances were distinguishable gray opaque material wine-red to pink opaque material colorless translucent crystals and metafile tellurium Analyses were performer separately on each type of material
1 Gray opaque material The x-ray diffraction pattern revealed LigtTe and LiTe no other lines were present The oxygen level was about 218 pom Specshytrograph analysts indicated the presence of about 01 w t molybdenum
2 Red-hue material Only a few crystals of all-red material could be isolated The remainder of the red-hue material was ground together with some surshyrounding gray material The x-ray diffraction pattern corresponded mainly to Li2Te A small amount of LiTe was also preset The oxygen content was reported to be about 275 ppm Spectrograph analysis reported lt00I wt 9 molybdenum
3 Colorless translucent nd isolated red crystals Both these products gave an -ay diffraction pattern corresponding to pure Lij Te with no indication of a second phase
To ensure a uniform product all the various colored materials were recombined and thoroughly mixed The LijTe mixture was then placed in a 2-in-diam tungsten boat which had previously been enclosed in a quartz bottle The quartz bottle was then evacuated sealed and heated to 550degC for about 16 hr The product obtained after cooling was almost completely cream-white However when the bottle was broken open the product began to turn beige upon exposure to the envishyronment of the inert-atmosphere box The product was then crushed roughly and placed in sample bottles On standing in the bottles the product gradually reverted to the red-gray color it had been before the heat treatshyment with the exception that the product in one bottle remained beige The reason for the lack of uniform behavior is as yet unknown Some of the darkened product was returned to the tungsten boat in another quartz bottle and (he heat treatment repealed it again turned the cream-white color The products both the light beige and the red-gray color forms gave x-ray difshyfraction patterns for a single phase LijTe Analysis of this LijTe is given in Table 31
T l r 3 J ABMywafU-TcaaJliTc
UU t i l r
l l lVI 1 laquo 5 - MI 1 - bullbull It IWI ~ raquo raquo - bullbull 5 Sraquo 4 r II 5
Li TV IMgt4T I mj r i LiTe bullbulln4r ~ bull 14- 05 XI lt - 5 raquo Innh4r ~ l ITI - 1511
-fjgt diftraciMi SMctcpfc SWfJr rhue 0ypm ipeani 740lltr l 275tMrri
MatyMtmdash i w i 005 ltlaquoraquo0I
T w p m iwt i lt00l lt 0 laquo l
Red-gray Li2Te was mixed with the amount o( tellushyrium required to satisfy the LiTe stoiduometry The mixture was then sealed in a qurtz bottle under vacuum and heated to 550degC for 2 hr The not liquid was dark metallic gray On cooling the solid appeared bright silver-gray The x-ray diffraction pattern conshyfirmed the presence of a single phase LiTe having a near body-centered cubic structure with a pscdo-ell lattice parameter of 61620 plusmn 0D002 A J The well-exposed Debye-Scherrer diffraction patterns suggest that the structure of this compound is more complex than previously reported2 Work will continue in an effort to describe this structure The oxygen content was reported to be 275 ppm Spectrographs analysis reported no molybdenum or tungsten contamination Analysis of this LiTe3 is also given in Table 31
3 2 SPECTROSCOPY OF TELLURIUM SPECIES IN MOLTEN SALTS
B F Hitch L M Toth
A spectroscopic investigation of tellurium behavior in molten salts has been initiated to identify the species present in solution and to obtain thermodynamic data which will permit the determination of the species redox behavior in MSBR fuel salt A previous investigashytion 1 had indicated that Te~ is present in LiF-BeFj (66-34 mole ) on the basis of an absorption band occurring at 478 nm when LiTe was the -Jded solute however the work wai terminated before these observashytions had been fully substantiated The current work is an extension of those earlier measurements which
5 C K Bamberger i P Young and R G ROM Inorg Suel Chtm 36115raquo U974)
31
should lead ultimately to a measurement ol redox equishylibria such as
LiTe bull H bull 5LJF = 3Li2Te bull 5HF II)
^Te bull LiF + ^ H = LiTe + HF 1
These data should then permit the prediction of teilu-num redox chemistry as a function oi LF gt l T F 4 ratio
During the past several months most ot the effort was devoted to assembly oi the apparatus necessary for the fluoride measurements Ths involved fabrication and assembly- ot the following furnace for the fluoride studies diamond-windov ed specirophotometrk cells a vacuum and inert gas system and a KHF saturator through which H is passed to generate HF-H mixtures of known proportions
Also during the period of preparation some attention was given to a supporting study in chloride melts The advantages of working in chlorides are
i previous ground-work investigations have already been reported7
2 chlorides are easier to hold in silica cells without container corrosion
3 the greater solubility oi the tellundes in chlorides may reveal greater detail because oi more intense spectra
Atsorption spectra have been measured for LiTo LiTej and tellurium solutes as well as during titrations of LijTe with Tej in the LiCTKCl eutectic 31 450 to 700degC These data indicate that at least two light-absorbing species are present in molten chlorides conshytaining lithium tellurides with compositions in the range LiTe to LiTe4 Furthermore an examination of Te 2 in the LCl-KCI eutectic has indicated thai there is a second species present besides Te which is formed at high temperatures andor high halide ion activity More detailed experiments are anticipated using purer lithium lelluride solutes in the diamond-windowed cell to demonstrate (hat (he additional species are not related to impurities from the reagent or silica corrosion
6 This work has done in cooperation with J Bryncsfad of I he Metals and Ceramics Division
7 I) M Cruen R I McBclh M S I osier and ( Y (roulhiimcl Phys Otcm 70i2t472 (l6gt
3 J URANIUM TOTRAFLUOftDE-HYMOGEN EQUIUHUUM IN MOLTEN FLUORIDE SOLUTIONS
L O Gilpatnck L M Toth
The equilibrium
LF 4ldraquo4H2lg) = UF J ldraquoHF|g) HI
is under investigation using improved methods of analyshyses and control The effects of temperature and solvent composition changes on the equilibrium quotient
Q = rraquo
are the immediate objectives of this work and are sought to resolve previous discrepancies noted in fuel-sal redox behavior
The procedure involves sparging a small (approxishymately 1 gl sample of salt solution (UF 4 concentration of 0038 to 013 mole liter or 0065 to 022 mole rgt) with H gas at 5S0 to 850degC until partial reduction of UF 4 to UF 3 is observed HF is added to oxidize the desired amount of LF j back to UF 4 When an equilibshyrium between the HF H gas mixture and the UF 3 -UF 4
in solution is reached a spectrophotometric determinashytion of the UFj and UF 4 concentrations is made These data are combined with the analytically determined HF(H2) ratio to obtain the equilibrium quotient at a given set of conditions
The assembly of the system for this experiment has been completed and measurements of equilibrium quotients using LiK-BeF (66-34 mole ^) as the solshyvent have been initiated Some delay has occurred because of trace water in the HFHj sparge gas which was responsible for the hydrolysis of uranium tetra-fluoride and the subsequent precipitation of 1 0 The problem has been partially alleviated by treatment of the KHF saturator gas supply lines and spectrophotoshymetry furnace with fluorine at room temperature Howshyever back diffusion of water vapor into the furnace from the exit gas line has also caused substantial solute losses and has been reduced by using higher HF-H2 flow
This research in support of the MSBR Program was funded by the KRDA Division of Physical Research
H I O Gilpaimk and L M Toth The Uranium Tetrafluoridc Hydrogen Fquilihnum in Mollcn Fluoride Solushytions MSR Pnygram Srmunnu Progr Rep Feh u 7 s ORNI-5rt47p43
32
rates Together these modifications have reduced the totute Kisses to an acceptable level (2^ per day i
Equilibrium has been achieved at 650X lor measured I F VFj ratios of approximately 02 X IG to X 10- Although the I F VF 4 values are reproducible a fixed KHF saturator temperatures the aaalyiicaily detennined HF values are not as yet Consequently the standard error (approximately 50lt) in the equilibrium quotients is soil rather high So tar a value ofQplusmn 10 has been determined at 650degC which compares favorshyably with the previous value of 116 X I 0 T Most of the immediate effort is being Jevoted to improving the precision of the HF determination
Tritium control in an MSBR would be favored by higher equilibrium quotients In an MSBR the I F UF 4 ratio will probably be fixed by equilibria involving the structural metals The tritium inventory will be established by the tritium production rate and the various tritium removal processes UQ is larger than previously anticipated the partial pressure of HF would be higher and the partial pressure of H would be lower than previously estimated Thus TH would be available at a lower concentration for permeation through the heal exchanger to contaminate the coolant loop (and ultimately the steam system) and a larger proportion of the tritium would be present as TF which would be removed in the helium gas stream
34 POROUS ELECTRODE STUDIES IN MOLTEN SALTS
H R Bronstein F A Posey
Work continued on development of porous and packed-bed electrode systems as continuous on-line monitors of the concentrations of electroactive subshystances especially dissolved bismuth in MSBR fuel salt In previous w o r k 1 0 a prototype parked-bed elecshytrode of glassy carbon spheres (MOO microns in dishyameter) was tested in the LiCI-lCCI eutectic system Linear-sweep voltammetric measurements carried out in the presence of small amounts of iron and cadmium salts showed that the cell instrumentation and auxilshyiary systems functioned successfully and demonstrated
9 G Long and F F Blankenship The Ftahiliiy of Uranium Triflimhde ORNL-TM-2065 Part II (November 1969) p 16 Kq 6 with xjyt - 0002
H H R Bronstein and F A Posey MSR Program Semi-anmi Progr fP raquolaquo Jl 1974 ORNL-5011 pp 49 51
II H R Bronsleir and F A Posey HSR Pro-am Semi-anmi Progr Rep reh 2H IV7S ORNL-5047 p 44
the sensitivity of this method of analysts However these measurements showed the need tot redesign oi the experimental assembly to permit removal and replaceshyment of the cell and addition of substances to the melt
During this report period the redesigned packed-bed electrode of glassy carbon spheres was tested again in LiCI-KCI (5SJMIJ mote ) eutectic since the beshyhavior of a number of electroactive substances has alshyready been established in this medium The packed bed of glassy carbon spheres was supported on a porous quartz frit and contained in a quartz sheath Another porous quartz frit pressed on the bed from above A glassy carbon rod penetrated the upper quartz frit to provide compaction cf the bed ana electrical contact with a long standee steel rod which was insulated from the surrounding tantalum support tube The oiectrode assembly was dipped into the melt so that the molten salt flowed up through the interior oi the bed and out an overflow dot By this means il was possible to obtain a reproducible volume of melt inside the packed-bed electrode
Voitairmetric and coUometric scans of the pure melt at 3raquo5degC showed that the background current was small A typical set of current-potential and charge-pountiai background curves is shown in Fig 31 - A 2-V
1 1 I flmdashImdashTmdashImdashraquomdashbull 1mdash T I mdash T 1 1 T mdashi 1 I I bull 1 l - laquo 0 0
to 0 5 0 0 -OS 10 IS ELECTKOOC P0TpoundlraquoTiraquoi ( n bull laquolaquoamp) (raquobull$)
Ffc 31 Linear-sweep voUMimetry and coalonef ry of cadshymium in LCI-KCI (588-412 mole gt eutcctic with a packed-bed electrode of glassy caboa spheres Curve A current backshyground (sweep rate = 10 mVsec) curve B current with Cd present (sweep rate = 5 mVsec) curve C background charging curve (sweep rale - if) mVsec) curve D charging curve with (d present (sweep rate = 5 mVsec)
33
range ot electrode potential could be swept without evidence of significant amounts ot ouduable or reducshyible impurities in the meli For calibration purposes a known quantity ot -radmium ions lCdgt was added to the melt lraquoy anodiation ol molten cadmium metal conshytained in a specially designed graphite cup which could he lowered into the melt The amount ot cadmium adod (Fig 311 was monitored by use oran electronic autorancui couometer
Following addition ol cadmium the voifammeinc and coulometric scans indicated that only a small fraction ol the known cadi-uum content inside the void space oi the packed-bed electrode was being measured- After removal of the cell assembly examination showed flat the glassy carbon contact rod had somehow fractured possibly due to excessive pressure from the matin stainless steel contact rod and resumed in lo of elecshytrical contact with the packe-i-Sed electrod
The -ell assembly was then redesigned and rebuilt to permit electrical contact to be maintained without undue pressure and to allow accurate measurement of the working volume of the packed-bed electrode The new design was similar to that of the previous cell except that the upper fritted quartz disk was permashynently sealed (o the surrounding quart sheath A small hole in (he center of the disk permitted loading of the daisy carbon spheres into the electrode assembly and provided accurate positioning of the glassy carbon con-act rod into ihe bed Prior to loading of the spheres
the volume contained between the porous quart disks was measured with mercury
Some voltammetric and coulometric scans in the presshyence oi cadmium ions are shown in Fig- 3 1 As in preshyvious studies in aqueous media with the packed-bed electrode2 more accurate analytical results were obtained on Ihe anodic half cycle (stripping) than on bulli cathodic half cycle (deposition) Approximately 40 mC of cadmium was estimated to be within the packed-bed electrode The coulometric results shown in Fig 31 n quite consistent with this value Thus it is possible knowing the geometry raquof a packed-bed electrode to estimate the response and sensitivity within reasonable limits (the accuracy oi estimation depends upon void fraction the accuracy of the volume measurement and other factors) Repeated scans over a period of many days showed good reproducibility and also established that diffusion through the quart frits during the time of measurement (only a few minuus) has very little effect on the results
12 I I R Bronstcin and I- A Posey Otrm Mr Amu Proxr Rep May raquo IW ORiSI 4976 pp 1119 I I
Another cell was pocked with jOOp-dum glassy carbon spheres and used to obtain the results shown m Fig 32- In this case a quantity of amp ions had been anodued into the melt in a manner ssraiar to that used for cadmium- At the time of these measurements the same melt had been in use for many weeks Fig 32 shows voiiammetnc and couloroetric anodic stripping curves in the vicinity ot the anodic peak for stripping oi bismuth which had previously been deposited on the imemal surfaces of the electrode during the cathodic ^ii cycle In agreement with observations of others we found that volatility of BiCl precluded close correshyspondence between added and observed quantities of bismuth and that the bismuth peak decreased steadily with time The appearance of the bismuth peak suggests that possibly some alloying of bismuth with the cadshymium look place
Other expeiiments on bismuth reduction and stripshyping will be carried out in the future in which cadmium used for calibration of the ceil sysreni is absent In addition the present apparatus wiL be used lto study the electrochemistry oi lithium teiluride in the UC1-KC1 euieciic Observations on lb tellurium system in the chloride melt may be useful in interpretation of tellushyrium behavior in later studies with MSBR fuel salt The
CWV-3WG 75 -Z99
TEMPERATURE 392-C if REFERENCE ELECTRODE laquoflaquolaquoCMraquo4r) pound
GLASSY CARSON SPHERE OMMETER -200raquogtCfm
04 03 02 01 00 -Ol -02 - 0 3 - 0 -05 -06 ELECTROOC POTENTIAL (rtAflAflCO (bullraquo()
F J2 Linear-sweep anodic stripping votUmmetry and coglometry of hianiirh efecfrodepooted onto a packed-bed electrode of gUscy carbon spheres Solid lines experimental current-potential and charge-potential curvet in ihe region of (he rmmuh stripping peak dashed lines estimated background charging curves
34
cajxabilify of the packed-bed electrode ot ciasv carbon tfetctci tot monitoring eieciroactrve species n molten sail has hem shown ugt be sattgttactor Consequently p bull aw now under wa raquo design jpd fabrKation ot cells and appaiaius lor sestmc the electrode system in mxten fluoride media induduw MSBR fuel salt- In Msmufh-coatauung fluoride metis whether bismuth iraquo present as Bt or LijBtor both it should be possible 10 identifgt and determine ihe quantities of each species The packed-bed electrode offer hope ut removin as well as monitoring dissolved bismuth m the fuel sail which may be present as a result of the reductive extracshytion process for removal ot fission products
iS FUEL SALT-COOLANT SALT INTERACTION STUDIES
A D Keimers D t Ilealherly
In the alternate coolant evaluation1 several areas of potential concern were defined with regard to the applishycability o( the conceptual design coolant salt | a B F 4 -NaF (gt2-K mole ^ l | for MSBRs These centered primarshyily arogtmd events associated with off-design transient conditions particularly primary heal exchanger leaks which would allow imermixing of fuel salt and coolant salt If coolant salt leaked into the fuel salt the quanshytity and rate of evolution of BF j gas from reaction lt 11
N B F 4 l d raquo o l j U M - B F l g gt bull N a F i d gt u e ^ lt I
would determine the transient pressure surges to be enshycountered in the heat exchancer and reactor Also preshyvious work 1 4 indicated a substantial redistribution of the ions LT Na Be F and BFlaquo~ between the resultshying immiscible two-phase system formed on mixing Lj BeFlaquo and NaBF 4 The solubilities of UF 4 andThF 4
have not been measured in such systems thus the disshytribution of uranium and thorium between such phases and the resulting concentrations are unknown In addishytion if oxide species were present in the coolant salt either deliberately added to aid in tritium trapping or inadvertently present due to steam leaks in the steam-raising system the precipitation of UO2 following mixshying of an oxide-containing coolant sail with fuel salt has not been investigated Therefore a series of experiments were carried out to investigate these areas
I J A D Kelmirs tl al Committer Report hvaluaiion of Alternate Secondary land Tertiary) Coolants for the Molten-Salt Breeder Reactor (in preparation)
14 V K Bamberger C h Baelaquo Jr J P Young and C S Shew MSR Program Semiannu Prop Rep reh 20 I96H ORNL-4254 pp 171 73
The experimental apparatus consisted ot a a u i u vessel heated by a quuri furnace so thai the raquoraquoraquottTvr of the resukmc phases ouid be observed at temp mure and measured with a cathetomrter The quari vessel extended up out of ihe furnace and was closed with an O-itne titling and end plate A nickci stilting shaft driven bgt a constant -speed dc r-fcgtllaquogtlaquo peneiiated the end plate and during live tests was dnven at a speed adequate 10 stir the two phases without appreciable vtsibW dispersion Access for sample fillet slicks was provided through the end plate as was done also for ihe argon inlet and exit lines A very low argon flow main-tamed an inert atmosphere over ihe melt during ihe experiment
Predetermined weights of fuel salt (nominal composishytion LiF-BeF ThF-lF 4 (Mfc-117-03 mole^raquo | and coolant salt |nominal composition NaBF4-NaF (2- mole ltl| were placed in the quart vessel and rapidly healed lo 550 C Bubbles of gas could be observed due to BF) generation via reaction I I I as soon as the coiilani sail melted during the heat up period When the temperature reached 550 ( counted as time zero stirshyring was initiated The volume ol the phases was periodshyically determined and filter-stick samples were taken at 30- or dO-rrun inieials
The reaction between the fuel salt and coolant sail proceeded slowly approximately 30 to raquo0 min was required to complete the visible evolution of BF 3 gas at 550degC When the initial coolant salt content was 20 wt or less of the total material no omlant salt phase remained after approximately I hr All the NaF disshysolved in the fuel salt phase and all the BF gas left the reaction vessel With larger initial weights of coolant salt up to 50 wt gt a small residual volume of coolant salt phase could be observed after I to 3 hr Severe corrosion of the quartz reaction vessel occurred at the interface between the coolant salt phase and the argon cover gas in the experiments with the larger initial weights of coolant salt presumably due to attack of the quartz by BFj via a reaction such as
2BF(g) + VjSiOjfc)- SiF4fggt + fcOjfd) (2)
In experimenis 6 and 7 holes were corroded completely through the vessel wall and the surface of the stirred molten coolant salt phase was exposed to air for I to 2 hr at 550degC
In most of the experiments samples of the fuel-salt phase were withdrawn at intervals of 1 2 3 and 4 hr Samples were also taken after the conclusion of the experiment after the melt had cooled to room temperashyture the quartz vessel was broken away from the solid salt All these samples gave essentially identical analyti-
Tabic 32 Compmiliun of fuel-Mil pliiH- ami cnulani-aalt phatv aflci contact al 550 C
h vpcrimenl No
Initiil imvlmc iwt raquo
Hu-I salt Coolant i lr
100 9( Ho 7l) 61) 51)
o II) o 3raquo 41) 51)
111
tgtHK 6 3 3 604 544 50H 44 0
I uclvill phase (mole gt
Nal IK-1 M i l I T
2 3 93
123 1911 63 366
17J 167 165 155 13 H9
NominaUomnoMUon l i l - -Bc l - -Th | - lt - l l (72-I6-I I7-03 mraquolc bull)
Nominal conipotttion Naltl- -Nul (92-K mole bull I
No coolant-suit phase remained
Not analyzed
115 105 106 |lgt9 96
ID4
I I I
I bull i2 IVH 94
Nal-
191 366 43 9
CoiiliiHvih phase IIIIOK- I
IWI l h l bdquo I T N i S i l
4 4 3H 3 9
ii IH n o l i (150 0 017 1)74 OlOH
lt 31 19
M 0 Nalll
lt5l IK 6 J 33
n 47
16 9
ft
36
cat values therefore tne fuel-salt phase analyse (Table 52) represent an average of 5 to 5 values Further supshyport lor the coateatun that react urns nrroHuK the fuel-salt phase were complete m feO mm c less t shewn In the plots of volume rs time in Fig3J The cootani-sai phase volume decreased raptdry tor about 30 mm due to reaction (1) thereafter the volume chance was slower presumably due to reaction i2h
It was irnpossibie to obtain coobnt-salt phase samples with the flier sticks both because the phase volume was small and the salt tended to dram out of the titer sticks Therefore aM coolant-salt phise analyses (Table 33) were from samples obtained after completion of the experiment and represent only smgje values
The analyses (Tabic 3 Jraquo show substantial redistribushytion of the ions Li Na and Be between the two phases Thorium and uranium exhibited low soiubiity in the coolant-sail phase Neither NaBF4 nor the oxyshygenated tluoroborate compound (represented as B 0 3
in the table) was soluble in the fuel-salt phase Fuel salt stirred in contact with a coolant-salt phase containing up to about 50 mole lt B0 3 showed no precipitation of LO Tht coolant phase compositions were ex-
onNL-DWG 75-raquo3748
rlX Claquo
1 0 -
X T
Cootant Solf Phase -
20 40 60 80 TIME (mi)
100 120
Fit bullbull Votame of coobnt-s-Jt phase and fad-nil phase vs fane in mixing experiment No 6 Initial mixture was 60 wi i fuel salt and 40 wt 1 coolant tall After heatiny lo 550deg C Mining was begun and tht depth of the two phase was periodishycally measured
F-laquo O
I n t u t i laquoaraquo4c bull
factual (bull4jac vilr Ml lt) ViM
l raquo bullbullbull 4gt gt- 5 bullbull bullraquo 4i M bullraquo bull bull bull
bullraquo 5 gtraquo MI 14
raquo - Na Nan bull Li bull ZBc bull 4Th bull 41 bull 4S
pressed (Table 33) m terms of the ternary system MF-B 0-NaBF 4 The compositions are dose to the glass-forming regions of the terra y phase diagram1 for the system NaF-BiC-NaBF where drscete comshypounds have not been established
The following pertinent observations can be made
1 The rate of evolution of BF gas on mixing was low- presumably the rate-limiting step is the transfer of NaF across the vflt-salt interface Thus in a reactor system with turbulent flow the release would be more rapid however these results are encouraging relative to MSBRs in that very rapid gas release reshysulting in significant pressure surges was not experishyenced
2 No tendency was observed for the fuel salt constitshyuents thorium or uranium to redistribute or to form more concentrated solutions or to precipitate folshylowing mixing of coolant salt into fuel salt These experiments do not yield information relative to mixing fuel salt into coolant salt since it was impossible to contain predominantly coolant-salt phase mixtures in quartz at 550C Thus the quesshytion of uranium (andor thorium) precipitation as lF4-NaF complexes as observed in an engineershying loop remains unresolved
3 Apparently an oxide species forms in the coolant-salt phase which is more stable than UOj since no LO-precipitation was observed Thus large amounts of oxygenated compounds could be added to the flu oroborate coolant salt for the purpose of sequesshytering tritium since leakage of such a coolant salt into the fuel salt would not lead to uranium or thorium precipitation
15 I Maya Sect 41 this report 16 H F McDuffie et al Assessment of Molten Salts ar
Intermediate Coolants for IWBRs ORNL-TM-2696 (Sept 3 1969) p 20
37
3 4 LATTICE AND FORMATION ENTHALHESOF FIR$T4tOlaquo TKANSmON^ETAL FLUORIDES
The pnmar bull purpose of (his inveMijpinw is to plaquoraquoraquowde a theoretical bans tor cnttcaiK evaluating the chermir-dynamic data thai raquoifl be blamed in an experimental program recently giiittled with Dmstuti ot Physical Research I undine In thf experureirraquo free enerpes of tormaiion will be deduced from emt measurements ot solid-etectriJyie caharuc ceHs The iirsi-roraquo transition rrcials include common sKucturai metab (Fe i Cgtraquo and other meuls iTi V) which may be used in fcaon or fusion reactors When these meuls are corroded or otherwise oxidized u fluoride media used m these resc-tors meial fluorides are formed reliable thermoshydynamic information for these compounds rs valuable in predicting their chemical behavior in the eactor system
For a metallic fluoride MFbdquo I where n is the valence of the metallic iongt the relationship between lattice enthalpy V and enthalpy ot formation is given by the equation
_y=-X Mgtbdquo nXly- ( I t
The lattice enthalpy is the best of the reaction
Mlggt + nV it) = MFbdquo(c) Craquo
at gtvl5 K The lattice enthalpy is very similar to the lattice energy the latter being someihat more diffishycult to obtain from experimental information 3Jr is the standard heat of formation of MFbdquo(c) A- is the standard enthalpy ltraquof formation at gtHl5 K of the gaseous cation and electrons ((gt formed from the crystalline metal
Hc)Mltg)+ gtlt( g) lt3gt
A-bull- is the standard enthalpy at ZW^K of a mole of gaseous fluoride ions formed from the ideal gases electrons and diatomic fluorine
V2F(sgt + ltr(g) - F (gf lt4gt
The enthalpies of formation for reactions lt3gt and (4gt are deduced mostly from atomic or molecular data Abdquo is obtained by summing the first ionization potentials of M and its enthalpy of sublimation and covcrling these quantities where necessary to 2ltraquolaquoI5 K values of bdquobull are given in Tables 34 and 35 The enthalpy of reaction (41 at gtXI5degKis ol24
Hmrraquotc bull Leal rrv-fcr
lt j l yi 5 4ilaquo 6 2 = si laquo2vraquo bull ltlaquo5i-Tiraquo bull 2 i v 5Slaquogt bullMgtC gt i2Wr 2raquoraquo i raquo f Crl I1 - 5 o5 3 6 - 5 Mnl 2ltgt5 4 - lf raquo 5 1 - I l-lt tif - 5 fc5s raquo - 5 C l - t5 - I f 2 laquo I V I 52 - bull raquo3 5 5 - bullltbull
t u t I I -bullbull 323 41 - - N nraquo I N Mraquo5 25
llaquolaquojgtltn rgt cntui-gt rmdashm lt I raquo-raquo- SRIgtS-IraquoS 34 bullgt cnhjlprs i ^uNinurn-n irin ret igt (atenve raquorjc prpjutraquogto encris sorretttrto irraquom elt 2 N BS Iivhnuai N-te 2gtMgt i llaquoI i ^iinucJ in this intetripibii ^NBS Icchnicjl V-ie bull-raquo 11t11 r V Rrufchiu tr j | iTim ThrmoJvn 6 bullbull( tgtraquo4( iXrrmrd tflaquom vgtlij ltal inkveil emf JJJ snmi in W H Sfcltr|[4i jnd J W Pjiicrv-n -laquoWtmmtm Mfidt 31 4 11 raquo-laquoraquo
f-IV-iF Thermhemif tehlt 2J e j NSRDS NBS 11111 I- Rudiicl jl J Oum rnt AifJ 1213 laquo11^1 NRS TcYhnhil tir raquobull lt fftSraquo
kcal per gram-ion it is based on Popps value 1 7 (34(H) eV) for the clectr gtn affinity of fluorine the dissociation energy lt 15 eV) measured by Chupka and Berkowit and the enthalpy difference of F (ideal gas) raquoraquo Hbdquo listed by lluiigren et al 1
The lattice enthalpies of the divalent fluorides arc listed in Table 34 and are plotted against atomic numshyber in Fig 34 The curious double hump has been intershypreted 2 0 in terms of ngand-field theory By this theory differences between actual values of A and those lying on a smooth curve drawn to fit the data of C a F Mnlj and ZnF are primarily due to ligand-field stabishylization energy (LFSfcl For (his series of compounds
bullThis rclaquoearcli in support of the MSRR Program wilt funded hy iho l-RIA Division of Physiiiil Research
17 II P Popp Xatitrforuh 22a 254 117) 18 W A ( hupka and J Berkowil Oiem Pint 54542h
ii nn 19 R Hullcren el al Selected ialun of the T)icrmltgt
dynamic Properties of the Elements p 177 American Society of Meials Metals Park Ohio 1973
2lraquo P (leor-e and tgt S McCliire p 381 in Progress in Inorganic Chrmisln vol I I- A Cotton ed Inieruience New York I W
M
750
_ TOO mdash
o E
x
690
6 2 0 -
I I I I I I I
I I I i I I I I I Cefj Stfj Traquoj V Crfj M Wgt laquo j MF 2 C 2 amp2 ddeg (T d 1 d J d 4 5 draquo d draquo draquo d
Fltg- 34 Lattice wlnaifiM of 3rf diva l l w i l u Solid circle (bull) are experimental aML catenated from Eq 11)error bars art uncertainties in ampH Open circle (-) are AftL mam Iwand-fldd stabilization energy Tnangks (A) arc aW^ minus both LFSE and Jahn-Tener energy Solid squares ltbull) were estishymated by adding LFSE plus 3 kcalmote as an empirical correcshytion to the smooth cone
the ligands are fluoride ions octahedrally coordinated (except for CaF 2 ) to the cation the ocuhedral field of fluoride ions acts to stabilize the splitting of tf-electron energy levels of the metal ions In a spherishycally symmetrical field the (-electron levels would be degenerate that is be at the same energy In Fig 34 the smooth curve drawn through for example N iF 2
represents the ampHt N i F 2 would have if the field of fluoride ions around the nickel cation were spherically symmetrical Octahedrally coordinated cations with unfilled half-filled or fully filled 2d orbitals will not have a ligand-field stabilization energy hence a smooth curve is drawn through CaF(tdeg) MnF(lt 5) and ZnF2(ltdeg)
Values of the LFSE can be deduced from optical spectra For FeF N i F 2 and CoFj subtraction of optically derived LFSE (Table 36) from bHL yields values (open circles in Fig 34) which are above the smooth curve by 2 to 3 kcalmole Similar LFSE subshytractions for CrF and CuF yield values (denoted by
laquoraquoraquo-raquo
Fhoodc iHf bullraquo- plusmnHL
ikai nMle) ileal mmfT l U a l motel
ScF 3941 2 1112 13224 r 2
w 33 1 3-$ 1222 1374 t 35 V F 2 9 S S I29raquo 1499 O F 277 US 14 I44S l 2 3 ^ I3gt l 143 t F e f bullSHi 13V4 1431 3 CoF mjf 1455-J 1457
N O W 1515-5 bull I 4 9 7 C - F ( 1 2 0 I S M 11520 lt - F 2 7 I3S9 143
bullban pomoMs from C E Moore SSKDS-NBS 34 (1970) earailgiri ot inlilmdashiliun from ref 19 catrnce state preparation energy correctnas from rcf 20-T N KeiaHani cf a l Cktm Tkrrmodrn t90 (1974s eO Kabascfccwsfci et at pp 3343S4 in JMrMftWpaf Iktmso-chematry 4th cd Pergamon Oxford England 197 Derived from toad garantc-cdl emf data gjien in W H Skdion and J W Patterson Less-Common Mruls 31 47 (1973) MBS Tetkmfl Note 270-4 (1969) fjASAF TkermochemicM Ttblts 2d ed NSRDS-NBS 37 (1971) Estanaied m this mvcstiplion hNBS TethmeitSote 270-3 (I96S)
open circles) above the smooth curve by 5 and 7 kcalmole respectively Both C I F J and CuF 2 (and to a lesser extent F e F 2 ) are known from crystal structure data to exhibit major tetragonal depai mdashres from octashyhedral coordination geometry This is attributed to the Jahn-Teller effect 2 which confers an additional stabilishyzation energy (Jahn-Teller energy is abbreviated herein as JTE) For CuF 2 and F e F 2 the JTE can be derived optically (Table 36) When LFSE and JTE are addi-tively applied to CuF 2 and C r F 2 the lattice enthalpy is overcorrected as is shown by the triangles in Fig 34
The methods outlined above can be applied to predict A t for V F 2 and T i F 2 Neither compound would be expected to have a significant JTE The formula used is
(5) Atfpound (kcalmole) = AHL bull LFSE + 3
where A V is the value for the compound lying on the smooth curve in Fig 34 The 3 kcalmole on the right-hand side of Eq (5) is an empirical correction reflecting
21 F A Cotton and C rmced Inortnic Chemistry 1972
Wilkinson pp 5deg0-93 in Ad 3rd rd Inter science New York
J9
OFSEk UTEXwl
IkvWt i lrgtH
H raquo T i 4 r |-ltU| OK laquo bullk-jl BRiic bull id lt
III ik^ai n-4ri
J S - l iraquoraquo I l raquo laquo n f i bulllt bull-
J- T i l bull I l Twr bull Mi t | 5 _ W 3raquo4
Jy gt f rlaquolaquoraquo laquo bull gt lt l | 4J6laquoI 5 laquo raquo l
J O K 1 laquobullbull l l raquo lt raquo I l f M a t l~4im bull bull bull I i
J- YtY 6raquogt - a I4i raquo -9
lt t raquo l 114ml lvi
J t raquo l Z l K I lb 5 Nil- lfc21 T I
J N i l 4 i m 54 lt u l I4UI0 4X4
J lt u K 4iKi 15 bull ~5t l raquo
JVjluc tivcn in D Orlkru Strut I RonJmg Berlin- 9 I 2gt 11raquo~Iraquo unlf otherwise m-JiutrJ l I SI minuinl very rlaquouchlgt i bullbull of Til- BiscJ ltgtn K N i F i l
Ksiirruted by jviumini lWgtq n ihj of Til-
Bjlaquod n iNH i gtVI Klinutrd hy Jraquorlaquonltcn mclhod |igtIX) jr r =1 -raquoltraquo cm --bullraquobullraquo Rouen t-Mirruic from JTI oi CuK Hiraquo-d n K( raquol ( ( Allen and K O Warren Struct laquorraquonWf SWw 9 Igtraquo7 nlaquogt| i
40
1550r
1500-
I I I I ORNL - DWG 75 - raquo3750 r I r
i i i I I l l I I ScF TFj VFj Crf MrF5 FeFj CoFj IWF CvF(ZnF)GaF ddeg d d d 1 (J4 d s dlaquo d 7 ltfraquo draquo d laquo
Flaquo 3 3 Lattice enthalpies of id trivalrnt Amides Solid bulltrclraquo laquoraquoi ace experimental plusmnH calculated from Eq (1gt error ban are published uncertainties in plusmnh Open circles ( ) are Af minus ligand-fteld stabilization energy Solid squares (bullgt are estimated by adding LFSF to the smooth curve
the difference between theoretical and thermochemical lattice enthalpies for NiF2 and CoF 2 The standard enthalpy of formation (Aygt for TiF2 and VF 2 is then obtained from Eq (1) and is listed in Table 34
Analogous considerations were applied to study AW for trivalent fluorides The data and results are preshysented in Table 35 and in Fig 35 The double-hump pattern of the data is evident in Fig 35 Subtraction of LFSE (given in Table 26) yields very satisfactory agreeshyment between theoretical and experimental lattice enthalpies of VF 3 and CrFj the agreement for TiF 3
(and for CoF 3 ) is less satisfactory As may be seen by the open circle below the curve in Fig 35 subtraction of LFSE from AHf overcorrects MnF 3 This is someshywhat surprising since MnF 3 with its 3d electronic configuration for Mn also has a azable JTE (Tabe 26) f the JTE were also subtracted the discrepancy from the smooth curve would be much greater In short the thermochemical data for MnF 3 are questionable
In estimating $HL and A for NiF 3 and CuF 3
(Table 35) only the LFSE was added to the spherically symmetrical values (ie smooth curve values) of ampHL In other words Eq (5) was applied without the empirishycal correction of 3 kcalmole
With regard to the A of the structural-metal fluoshyrides the theory as applied above suggests that there is little need to determine AVf for NiF 2 Moreover from the value of Afy of TiF 2 obtained in this study it is understandable why TiF 2 has never been prepared as a pure solid it can be easily shown that TiF 2 would readily disproportionate to TiF 3 and Ti However a more accurate experimental determination of A7 for TiFj would be desirable for both practical as well as theoretical reasons The same may be said for V F 2 VF 3 CrF2 CrF 3 FeF 2 and FeF 3
4 Gootint-Sak Chemistry A D Ketmers
41 CHEMISTRY OF SODIUM FLUOROBORATE
L Maya W R Cahill
The composition of the condensable fraction of the vapor piiase in equilibrium with molten fluoroborate can be defined by the system HuBF 4-HB0 2-H 20 as described in the previous report1 The work done durshying this report period was aimed at spectroscopic identishyfication of the molecular species present The B NMR as well as IR and Raman spectra of BF-2HjO FSFi(OHh- and of other intennediate compositions was obtained Dihydroxyfluoroboric acid (DHFBA) participates in exchange processes which could be desshycribed by the following equilibria
2HBF2(OH)2 = BF -H 2 0 + HBO
BFj-H 0+HBO = BF-2H 20 + HB0 2
The presence of HjBOj and HB02 was detected by 1R and Raman spectra and the pronounced broadening of the F and B NMR signals is an indication of exshychange processes The Raman spectrum of DHFBA indicates that this compound is a tetrahedral molecule Exchange processes were not detected for BF 3-2H 0 This compound appears to be stable at room tempera-twe The structural information derived from the Raman spectrum which identified BF 2H 2 0 as a
tetrahedral molecule agrees with the x-ray structural determination2 of this compound
Additional samples of condensate collected during the operation of the Coolant Salt Test Fanlity (CSTF) were analyzed (Table 41) Silicon is present because of attack on the glass trap used to collect the condensate Variations in the chemical composition of the samples can be interpreted as an indication that the condensed material is not a single molecular compound but rather a mixture formed by combination of the simpler gasshyeous species present gtn the system that is H 2 0 HF and BF The relatively high tritium content of these fractions should be noted Tritium is present in the system since some oi the Hastelloy N in the Icop was originally used in the MSRE The condensates show a tritium concentration factor of about I0 5 relative to the salt suggesting that fluoroborate coolant salt [NaBF4-NaF (92-8 mole )] may be sn effective means of concentrating and conveying tritium out of ikt system
Attempts were made to generate a condensable fracshytion in laboratory-scale experiments by heating oolant salt containing up to 200 ppm H as NaBFOH to 400degC in a closed system equipped with a coid finger The OH~ concentration in the salt decreased to 50 ppm and the composition of the condensate in a typical run was 532S H0BF 41483 (H0) 2SiF t anr 32^ free water found by difference The boron concentration in the condensed material did not reach as high a level as in
ORAL summer participant I L Maya MSR Program Semiannu Progr Rep Feb 28
VZ5 ORNL-5047p47 2 W B Barn and G B Carpenter Acta Ova 17 742
119641
TaMr 4 1 Analyses of CSTF trap coadeasttes
Sample Operation period Amount Chem
HOBF
ical compoMt ion Tritium content
imCifi Operation period Amount Chem
HOBF HBO SF
Tritium content imCifi
1 2 3 4
1972 11475 12475 31475 41575 41575 56lt75
Not avail 100 me
25 f 800 me
604 923 841 830
157 0
124 121
Not del 21 40 01
08 lo 30 r
57 34 06
Approximate amount Some of the material remained in the trap ^Difference(torn I0fr nH0 Given at a ranee Apparently more than OM simple was analysed for tritium content Data from A S Meyer and J M Dale Anal Chem [Mr An mi Pto0 Rep Jan 1974 ORNL-4930 p 28 The loop was not in operation between 12475 and 31475
41
42
the CSTF samples and there was considerable cor-bullosion Nevertheless these experiments showed a posshysible mechanism for the conversion of dissolved NaBFOH into a volatile fraction
An apparatus was assembled to measure he vapor d^rcity of BF i -2H G and related compounds at eleshyvated temperatures to determine the degree of dissociashytion of these materials This work tested the hypothesis that the condensable materials collected in the operashytion of the CSTF are completely dissociated at opershyating temperatures (+00~600C) and only combine to form more complex molecules in the colder parts of the system The procedure consists in measuring the presshysure developed in a closed system conuining a known amount of BF -2H 2 0 or DHFBA in order to establish the degree of dissociation according to the equilibrium described below
BF-2H 2 0 = BF+2HjO
At this time volumes in the apparatus have been detershymined and pressure determinations have been made using argon as a test gas Initial runs with BF 3 2H 2 0 indicate that this compound may be completely disshysociated at 400degC
Work on determining the oxide species present in molten fluoroborate is being continued and the survey1
of the system NaF NaBF4 BOj at 400 to 600degC has been extended to include IR and x-rav diffraction analyses in addition to physical and chemical observa-tiorii of the behavior of ^elected compositions The observations indicate that there are three main areas in the system
1 A region of compositions in which BFj is evolved This occurs with compositions having a deficiency in terms of equimolar ratios of NaF relative to the B 2Oj present
2 A region of compositions in which stable glasses are formed on cooling This corresponds to mixtures containing more than 33 mole B 2 Oj
3 A region in which crystalline phases and glasses coshyexist The tendency to form glasses on cooling decreases with decreasing B 2 0 j content
Usually coolant salt (NaBF4-NaF (92-8 mole )| contains relatively small amounts of oxide up to 1000 ppm and its composition lies within area 3 thus work has been directed toward characterizing the oxide species in this area At least two species were present one formed at the boundary of the glass area (high oxide content) and the other was NajBjFraquoOj which formed in compositions having NaFNaBF 4 B 2 0 mole ratios of 221 and 241 and was possibly present in
compositiors containing as little as 3 mole 7c BjOj Experiments at the 15 to 40 mole B Oj level approaching the coolant composition have been imshypeded by the relatively low sensitivity of IR and x-ray powder diffraction The difficulty with IR using the KBr pellet method arises from the fact that ~t thlaquoe oxide levels the only band not covered by BF 4~ absorptions is the one at 810 cm 1 This band has a relatively low absorptivity and it is common to NaBFOH NaiBzF0 N a B F t O and possibly other BOF compounds although the intensity and line shape are different for each compound A more certain IR identification can be made only when at least two topical bands can be identified (presently observable only at higher concentrations) as was the case in the identification of N a J B 3 F t O J at an oxide level correshysponding to 14 mole BJOJ Difficulties with x-ray diffraction arise from the low sensitivity of this techshynique coupled with the fact that the species have a tenshydency to form glasses Raman work on melts is being planned as the next step in this study
42 CORROSION OF STRUCTURAL ALLOYS BY FLUOROBORATES
S Cantor D E Heatherly B F Hitch
Alloys containing chromium in contact with molten NaBFlaquo-NaF would be expected to form a boride beshycause the reaction
(I + jr)Cr(c) + NaBF 4(d) + 2NaF(d)
= NaCrF(c)Cr xB(c) (I)
has a negative standad free-energy change (AG 0) At a temperature of 800degK ACj 0 o = - 1 0 kcal This value is based on an estimated standard free energy of formashytion (SGj) of NaCrF of -600 kcalmole In reaction (I) the exact value of x is unknown however AG of the more stable chromium borides (Cr2 B Cr5 Bj) is estishymated to be - 2 2 kcal per gram-atom of boron1 In nickel-base alloys reaction (I) may proceed more readily because of the probable exothermic nature of the reaction
CrTBfcgt +yNKalloy) = Cr(alloy) bull NiyBfc) (2)
3 O H KrikoriMl EstiirMion of HtJl Capacities and other Thermodynamic Properties of Refracsorv Borides UCRL-51043(1971)
4 O S GordkiN A S Dnbrovm O D Kokimkon and N ACherkovfun toys Chem 44431 (1972)
43
Assuming that AG of NiyB equals its enthalpy of formation AG for reaction (2) is about - 3 kcal per gram-atom of boron
An experiment to determine the extent of boride formation in the nickel-base alloys Hastelloy N (7 Cr) and Inconel 600 (15 Cr) has been in progress for sevshyeral months In this experiment mrtal specimens are equilibrated with NaBF4-NaF (92-8 mole ) at 640degC under an argon atmosphere and are periodically reshymoved washed free of salt using water and analyzed by spark-source mass spectrometry (SSMS) and less routinely by ion mkroprobe mass analysis (IMMA)-1
Analysts for boron on specimen surfaces by SSMS sugshygests some boride formation Hastelloy N specimens that had equilibrated for up to 129 days were found to contain 30 to 1000 ppm B Inconel 600 specimens conshytained 80 to 2000 ppm B Control specimens that had not been in contact with the molten salt showed 5 to 20 ppm when analyzed by SSMS Boron in Inconel 600 increased with equilibration time but with Hastelloy N the data were much more scattered and showed virshytually no time dependence
Several specimens analyzed by SSMS were also investishygated by IMMA Boron was present within the first few hundred monolayers of metal in inclusions also conshytaining sodium and fluorine in specimens of 2 Ti-modified Hastelloy N that had equilibrated for 72 days These contained 150 ppm B as determined by SSMS
5 Spark sowce mas specttomeuv and ion microprote mau analyss performed by die Analytical Chamstiy Dmson
The only plausible explanation seems to be that some NaBFlaquo remain on (or in) the metal surface despite the vashing (5 -10 nan in boiling water) intended to remove adhering traces of salt Some of the scatter in the boron analyses by SSMS is probably due to salt contamination of the metal surface Inconel 600 specishymens scanned by IMMA sholaquoed a similar pattern of surface inclusions contami^f B Na and F Unfortushynately IMMA does not provide quantitative analyses for these elements As yet the extent of boride formation cannot be quantified in either Hastelloy N or in Inconel 600 by a combination of SSMS and IMMA Probably however reactions (1) and (2) occur to a small extent boride is deposited at levels not greater than 500 ppm bullin Hastelloy N and not exceeding 1000 ppm on Incond 600 after four months of contact with molten NaBF44aF
IMMA was also used to obtain depth profiles of alloy constituents through about 5000 layers In control specimens elemental concentrations were uniform with depth far equilibrated Hastelloy N molybdenum was uniformly distributed throughout the depth explored but chrofiuuip and titanium concentrations increased linearly from the surface inward the iron concentration appeared to decrease slowly with depth Equilibrated Inconel 600 showed virtually no chromium in the fust 500 layers but chromium increased linearly in the next 4500 layers iron and nickel were uniform through the depth studied Thus IMMA indicates that chromium is selectively oxidized by NaBF -NaF (92-8 mole gt or by oxidants contained in this molten mixture
5 Development and Evaluation of Analytical Methods
A S Never
51 IN-LINE ANALYSIS OF MOLTEN MSBR FUEL
R F Apple D L Manning
B R Clark A S Mever
Corrosion test loops described previously have conshytinued operation with circulating reference fuel carrier salt LiF-BeF2ThF4 (72-16-12 mole ^ ) No additional loops hart been placed in operation during this reportshying period although several ire expected to begin opera-lion within the next few months
Measurements of the U-3 ratio in the forced conshyvection loop (FCL-2b) indicate a steady-state value of about 100 (Fig 51) This is somewhat lower2 than the
1 H E McCoy el al MSR Program Senumnu Progr Rep ug 31 1974 ORNL-50 I p 76
2 A S Meyn ec al VSt Program Semtcnnu Pro Rep Feb 28 1975 ORNL-5047 p 52
i MNL- om 75-1205
lt 1 1 1
3 V f mdash
amp amp amp
s 8 - i
bull bull
c I -J
m c
1 - i
-
2 bull bull
1
bull bull bull bull bull bull
raquo
bull bull bull
J _
bull bull
bull mdash
90 100 ELAMCO Tim
ISO 200 ltlaquobullraquoraquo)
apparent steady-state value obtained with the fluorid mixture LiF-BeF-ThF4 (68-20-12 mole 5gt indicating a less oxidizing melt The melt which started al a ratio of around 1000 reached this level via a redox process which presumably involves iactraquolaquoi ith the chromium in the walls of the vessel or in the specimens No atshytempts have yet been made to reoxidize the U3 in the melt by suitable additions of NiF or some other oxishydant It is interesting that the decrease to a steady-state value occurred after about 75 days ith a rapid deshycrease in the first 30 days Previous data from the expershyimental fuel showed2 a rather stable value near 10 for aoout 60 days until beryllium additions were made to force reduction of the U4
Some of oscillations in the data probably result from air contamination with subsequent oxidation when the loop was down This was most prominent with the experimental melt (68-20-12 mole S ) when the U43 ratio was substantially greater than the steady-state value reached at a later date
Ratios of U7U measured in the two thermal conshyvection loops NCL 21A and NCL 23 are summarized in Figs 5_2 and S3 respectively No unusual trend is apparent in the oxidation-state history of the fuel melt in NCL 21 A This loop was operated for about 240 days with Hasteiloy N corrosion specimens The curve shows a rather dramatic rise in the ratio whenever new specishymens are added This effect is attributed to additions of moisture and air which partially oxidize If3 A recover to lower ratios follows each increase in repetitive fashshyion
rj 1 t
OMl-Mt 79-OOSr 1 1 i
5 w i 1 V z
s Jr X
I bull 1
i 1 f
4 ^v bullw raquo bull
1
mdash bull
i i
bull bull
1 A- 1 100 190 ELAPSED TMfC
200 I )
290 300
FfcS1 Lmdash l gtFCL-2fc Fig 5J
NCL-m vmdashw
44
45
ORNL- DWG 75-12055 i i
1 i 1
2 bull 4 mdash 8s laquobull bullo
=3 i 3 bull copy
y i
bull bull bull bull I 1
i X bull bull bull
bull I I raquo IA raquo s s
bull bull bull bull bull bull
bull bull bull bulllt
laquo bull
I i 1 1
50 100 150 200 ELAPSED TIME (dors)
F4- 5-3- L LJ- ratios M rfcemal cowcctioa loop NCL-23
250
The U in the mdl in the Inconel 6CI loop NCL 23 wso aptdly retiuoed untS a V^iU ritio of around 40 was reached Since then the ratio has continued to decline reaching a relatively stable value near 5 The high level of chromium in the Inconcl 601 (23 wt lt) provides a sufficiently active reductant to reduce the U 4 more extensively than has been observed in Hastel-loy N loops therefore the greater U 3 concentration is not surprising
S2 TRITIUM ADDITION EXPERIMENTS IN THE COOLANT-SALT TECHNOLOGY FACUITY
R F Apple B R Clark A S Meyer
One major concern in the development of an MSBR is the release of tritium to the surroundings A potential method for limiting tritium release rates to acceptable levels involves trapping and removal of the tritium in I lie secondary coolant system This method must be tested before a complete understanding is possible of the manner by which tritium will be retained in an MSBR The present series of tritium addition experishyments involving sodium fluoroboraie will provide data on his method
The Coolant-Salt Technology Facility (CSTF) is being ltperated for testing the NaBF4-NaF eutectic mixture
with regard to its suitability as a oossible secondary coolant system In cooperation with loop engineers and technicians the Analytical Chemistry Group has been engaged in experiments to determine the fate and behavior of elemental tritium added directly to the cirshyculating salt to simulate at least in part the predicted transport o tritium into the coolant system via diffushysion through the primary heat exchanger This section describes the methodology and results of the first two experiments
About 80 mCi of tritium (diluted about 11000 with protium) was introduced into the salt stream over a period of about 11 hr beginning on July 17 Tritium concentrations were measured in the salt and the cover gas during the addition and for several days thereafter Salt samples were collected directly from the pump-bowl access port with a copper thimble covered with a copper frit One-gram samples of the cooled salt were diluted volumetrically and aliquots were mixed with a scintillation emulsion for beta counting
Cover-gas sampling has proven to be somewhat diffishycult At present a sidesfream is being sampled the diffishyculty arises from the passage of this stream through a nickel sampling line that is not completely inert chemishycally to cover-gas components Thus the amount of eleshymental tritium finally measured may not be an accurate
46
measure of tritium level within the loop gas system-More definitive experiments will require the use ot inert precious metals in the sampling system to remove doubt of chemical alteration of the cover-gas stream composishytion by the sampling system
The off-gis collection train consists of
1 a series of three water scrubber pretraps which serve to trap BFj and any other water-soluble compounds
2 a hot (400degC) copper oxide-tilted tube 3 a condensation trap to collect water formed in or
passing through the copper oxide 4 a liquid-nitrogen cold trap to remove the last trices
of water 5 a wet test meter to measure the volume of the iner
gas component of the cover gas that is helium
Results of the first injection experiment are summarized for the offgas (Table 51) and salt (TaWe 52)samples
Several days after operation had begun some liquid collected in the short glass section between the stopshycock used to divert the gas stream and the first trap in the analysis train The liquid was washed from the glass counted and found to contain about 60 jiCi of tritium This discovery clearly complicates the interpretation of previously collected samples since a large portion of total cover-gas tritium never reached the analysis train Furthermore no conclusion is possible regarding the chemical state of the tritium in the liquid The data suggest urn the concentration of elemental tritium
TabkSI TritimroMcM
iaCSTF
Tritium in ltas Time tpCimO
HOvluWe Fiemcnlai
17 1046 23 34 1305 07 12 1700 14 170 1 9 i i 1 93 2243 14 830
18 0100 32 420 0805 73 61 1000 44 71
19 1037 790 62 21 0905 1800 13
1325 50 13 22 0925 55 58 23 1303 85 29 24 1000 300 22 25 1315 340 26 28 1245 10 27
TaMrS2 TtitmmcoatcM mslaquot sMf tn rflrtfiol w i l i i jjiiwon mCSTF
Date July
Simple No
Time Tritium inCi (l
1 45 IKW 12 46 I3MS raquo 47 1512 35 4 1718 51 49 1930 9 j 50 2145 73 51 2321 H 2
1 52 1102 32 53 1912 20
laquo 54 9130 15 SMV 0952 75
21 55 1132 16 bullraquo2 56 1400 16 23 57 1330 20
increased in both the cover-gas and salt samples when the liquid was washed out between sampling periods I July 23-25)
A second tritium addition was made August 5 During this experiment no changes were made in the sampling apparatus but that region of the sampling train (desshycribed above) where liquid had been accumulating v as washed with each sample collection and counted sepashyrately The tritium found there was added to the water-soluble tritium measured in the pretraps Data for this experiment are summarized in Tables 53 and 54
An exhaustive analysis of the analytical and sampling aspects of these data is not warranted at this time since several variables which affect the addition sampling and the tritium losses have not yet been established A general discussion on the oehavior of tritium in the CSTF is given elsewhere1 The preliminary data are sufshyficiently encouraging to merit a more extensive investishygation into the extent and mechanism of tritium intershyaction with sal and cover-gas components Plans are now under way to monitor the tritium diffusion through a portion of the loop wall and to measure the level of active protons in the salt during addition of tritium A more intricate bull over-gas sampling device (a probe designed for the sart monitoring vessel or salt sample port) is being considered and may be fabricated if no simpler solution to the gas sampling problems can be found
3 Reference Sect 112 thn report
47
TaUeS3 Jiitmtm content in cover-gas amahs after jtvoad tritium aMinoa
mCSTF
Tricium m ja D l l e rime laquopCimll
(AlKWM) HOvi luhk HcmenuJ
5 0730 96 o5 ltmraquo HO 2 2 1130 22oo 10 1330 5JWgt 20 1530 7500 27 1830 13000 34 1920 13000 39 2100 12000 40 2315 9300 39
6 laquoP3n 9300 2 I I mi ltraquo) 16 1500 6500 i4 2000 4700 10
7 0940 3300 68 1415 2400 49
O93o ltraquo00 34 9 1450 1600 52 to W40 1300 2 1 1230 900 2 J 12 1010 570 11 13 1010 23o 0 15 inoo 1X2 lO llaquo iraquo935 76 05 21 1010 73 o j
TaMr 54 Tribmn content m sak s a f k i after moan H i r i mdash aaditioa m CSTT
Dale Sample Trunin iAapnU No m lad-e l
4 5 1313 nraquo 5 59 (1954 90
60 1145 21 61 1350 36 62 IS4ft 52 A3 IX4X 7 | 64 1932 6ft 65 2125 71 66 2335 50
6 67 lift in 30 6ft 157 19 A9 2 lraquo 16
7 To IOI4 9 5 71 152 ft 1
T 1 lolft 36 9 73 0916 4 2 I I 74 124ft 39 12 75 1035 14 13 76 I04K ^ 1
15 77 IOIO 14 I I I 7raquo IOIO 07 21 SMV IOA l3fW o5
5 3 ELECTOOANALYT1CAL STUDIES OF IRON II) IN MOLTEN LiF-BeFj-TkFlaquo
(72-16-12 MOLE 9tgt
D L Manning G Mamantov
Electroanalytical studies in molten fluorides have particular importance tor possible use as in-line analytishycal methods for molten-salt reactor streams Irani II) is a corrosion product present in molten-sIi reactor fuels We have previously carried out electrochemical s tud ies of i r on ( l l ) in molten LiF-NaF-KF ( 4 6 5 - 1 1 - 5 - 4 2 0 mole L iF -BeF 2 -Z rF 4
(696-254-50 mole ) and NaBFlaquo-NaF (92-8 mole ) Since the fuel solvent for the MSBR is a thorium-containing salt LiF-BeF ThF 4 (72-16-12 mole )it is of interest to conduct vortasnmetnc and chronopotenti-ometric studies of irondl) in this fuel solvent To detershymine concentration andor diffusion coefficients by linear sweep voliammetry it is necessary to know whether the product of the electrochemical reaction is soluble or insoluble The measurements discussed bdow were dace with this purpose in mind
A volummogram showing the reduction of ironOU Fe2 -raquo Fe at a gold electrode is shown in Fig 54 The circles represent the theoretical shape based on current functions tabulated by Nicholson and Sham for reversible wave where both the oxidized and reduced forms of the electroacthre species are soluble Thus even though Fe2 is reduced to the metal at gold the electrode reaction very closely approximates the soluble-product case apparently through the forrmtion of iron-gold surface alloys Further evidence that the Fe3 - Fe electrode reaction at gold conforms to the soluble product case is illustrated by the chronopotenti-ograms in Fig 55 The ratio of the forward to reverse transition limes ir^r) compares favorably with the
4 D L Mannmc Votcaninernx- Sradaroif Iron m Molten Lif-Nar--Kr fVermwwj Chen 6 2 2 7 i | 9 6 3 l
5 D I Mannine and G Manunfti X j p d San Voium-metric jnd CrirraquonnjgtotentKgtroeirraquo Sludirt igtf Iron in Molten H w r e k W tleclmtntl Oirm 7102 H964raquo
6 I I W Jenknu D I Manmae and O MamantoT Flec-irnde fotentiaU of Several Redlaquo Conple in Mollcn Hno-rnfeO Nmntchrm Sgth 1171 S3 119701
7 f R Clayton it HeciiochemK-jJ Slwbe in Molten Hnoride and Fraorntmrawv doctoral dtunalnm Imvenm of Tenncvee December 197) p ft2
ft A S Meyer et j l MSft Program WniMwn rop Rep Aug M 9 T 4 ORNl-laquo72Xp 44
9 R S Nicholson and I Sham Theory of Stationary FKtrode foiarocraphy J Oitm 3 7 0 7 I | 9 O I
48
QWNL-PWG 75-11275
I I I I I I I 150 tOO 5 0 0 - 5 0 -WO -150
POTENTIAL mV
Fy- 54 Stationary electrode watamumapam for e refacshytion of r V af gt faM electrode bull Broken UF-ueF-TnF Po-lentil axis B ltf - poundbullraquo-- Solid line is experimental Circles are theoretical dupe lor soluble product Iron) III concentration 0027 f electrode area 025 cm s lemperature 650 C
theoretical value of 3 (ret 10) for the soluble case which again points to the formation of surface alloys
The reduction of Fe2 at a pyrolytic graphite elecshytrode is illustrated by the vultammogram in Fig 56 and the chronopotentiograms shown in Fig 57 For the reversible deposition of an insoluble substance where n = 2 the voltammetrk Ep - pound p I = 303 mV at 650degC (ref II ) is in good agreement with the experimental value The chrooopotentiometric ratio (zyrr) is approxshyimately unity which also h indicative that Fe2 is reduced to metallic iron without any apparent interacshytion with the pyrotytic graphite and that all the iron is stripped from the electrode upon current reversal Therefore iron appears to be reversibly reduced to a soluble form at gold and to an insoluble material at pyrolytic graphite Thus the effect of electrode subshystrate on an electrochemical reaction is illustrated by this example
Chronopotentiograms for the reduction of Fe2 at an iridium electrode at 518 and 60DdegC are shown in Fig 5 8 The ratio at S I8degC is approximately unity and is 3 at 600 a C which is evidence that Fe1 reduction at iridium approximates the insoluble-species case (as with pyrotytk graphite) at SI8degC and the soluble-product case (as with gold) at 600degC This change in reduction behavior with temperature was not as pronounced at gold or at pyrolytic graphite
10 W H RimjnMn Oirowopoecmwiweiiic Transition Times and The Interpretation^W Chem 321514 (l0gt
11 C MwuMm D L Manm and J M Dale Reversshyible Drpnsitrxi of Metal on SoM Electrode by Voflammetry wnb Linearly Vary in Potential tlrctntml Ckem 9 253 tl9raquo5gt
The chronopotentiometric transition time r for an ekctroactiw species is given by the Sand equation 2
Average diffusion coefficients oi Fe2 in this melt evalushyated from the chronopotemiometric measurements by means of the Sand equation are approximately 42 X 1 0 80 X 10 and 15 X I0 5 o n 2 sec at 5IX 600 and 7O0degC respectively
54 VOLTAMMETRIC STUDIES OF TELLURIUM IN MOLTEN UF BeFThF 4
(72-16-12 MOLE )
D L Manning A S Meyer G Mamantov
Tellurium occurs in nuclear reactors as a fission prodshyuct and results in shallow intergranular cracking in structural metals and alloys i It is of interest to charshyacterize this substance electrodiemicaliy and ascertain the feasibility of in situ measurements by eiectroana-lytical means We previously14 carried out preliminary polarization measurements at a small tellurmin poc1
electrode in molten LiF-BeFj-ZrF to estaampbh (he potentials at which tellurium is oxidized and reduced in the molten fluoride environment These preliminary observations indicated that the electrode reactions are complex
For tellurium screening studies J R Reiser of the Metals and Ceramics Division fabricated an experishymental cell equipped with viewing ports and electrode ports for studying the stability of lithium teUuride LijTe in molten LiF-BeF-ThF4 The Li2Te was added as pellets following which voUammograms were reshycorded at gold and iridium electrodes
As LsTe was added to the melt the voliammograms became com4ex and are not yet completely undershystood For clarity pertinent observations at the iridium and gold electrodes are tabulated separately
1 Upon adding one 35-mg pellet of Li 2Te a reducshytion wave observed at 09 V vs the It quasueferencc electrode (ORE) disappeared- fhis wave is not yet
12 Pan Drlahay p 179 IT in Srw hturumenuH Mrlkodt m Eltcmxhrmotry htterscience New York 1964
I J H F McCoy Maiernh tor Salt-Tontammt Veswlsand Pipmt The Dtvrktpmtni mtd Vlaquoftn of Mollrn-Sali Rnclon OftNMH|2ll-ebnary 1975raquop 207
14 A S Meyer el j | JW hnmm Stmmmmi Prop Rrp Aug SI 1974 ORNL-5011 p 42
49 ORL-0G 7S-M277
OWEVT TiME CURRENT TIME n l tslaquocdraquo) (mA) (stcdw)
5 J Cyclic ibroouyofcplimi mdash i for w wountioa of bulloa j l l ) at a f o M efcinuiat Foraufciy of troMllt X15ttecti ode jrcj
identined The pellets did not melt or dissolve immedishyately Relics ot the pellets could be seen on the surface tor several days The windows of the viewpcris became coated with a bluish-fray deposit after a few days making viewing of the melt impossible The bluish-pay deposit is believed to be tellurium metal Tim indicates that tellurium species added as L i Te are not stable in the melt
2 Voltammograms recorded in molten LiF-BeF -ThFlaquo after additions ot Li Te did not reveal any waves that could be attributed to soluble dectroactive tellushyrium species Chemical analysis indicated lt5 ppm Te in the melt
3 Abo at an indium electrode a reduction wave was observed at 045 V vs the Ir ORE which was reasonshyably well defined at a scan rate of 002 V sec This wave is due to Cr J reduction the wave height increased upon adding CrF 2 but did not change upon adding LijTe At our normal scan rate of 01 V sec the wave was not well defined which explains in part why it was not positively identified on background scans that are norshymally recorded at 01 V sec
4 Voitammetrk waves indicative of leilunde firms on a gold electrode were observed However these waves disappeared after adding CrFj to the melt The volt-ammogramlt recorded at gold foflowmg the L i 2 Te addishytions became complex and the electrode reactions are not yet resolved
Additional volrammeirr measurements are planned whereby the supposedly more soluble and stable LtTe species will be added to the fuel melt
igt 2$ c m 2 temperature M W C potential io le wilts s Ir QRF
ORNL-DWG75-11276
l _ _ J I I 1 bull 0025 0 -0025 POTENTIAL V vs U ORE
fSA Statpmry laquofctWodc to l lmdashuupaw for IW rwJt-timi of imKl l ) at a bullyrorytic gray laquonlaquouut InwfoMe prodshyuct j i 650 ( ibrnretH-jl Kp hbdquoi - 05 mV me-i-uired 3 0 mV InHMlll ctgtiraquocenirjiHgtn n02 electrode jrea 01 o n
so
C---+C S -raquoTS
TMpound
F-f57 Cycfc Hraquoi-o-i--uli bull gt bull y mdash l fat HJC rofactioti of mottlU M raquo etcmgt4e area 01 cm 1 -cmr-mare 650C potcnlbi - o k tuli VI Ir URF
-TIME
FomuiilT ot irondh iraquoiraquo
vt
w i l l
Ffc SJ Cydm ctmomtfottmtia^mm for r jrra n2 a n 1 po-rnlnl laquoale raquonltlaquo v Ir QRF
ft- bull v -
r of MMdl ) at i Formality of -rolaquo(llgt OfMVrfcctr-i-Jr
Part 3 Materials Development H fe McCoy
The main thrust of the mateiials program is the develshyopment of a structural material for (he MSBR primary ciicuit which has adequate resistance to embrittlemeni by neutron irradmion and (o shallow intergranular attack by fission product penetration A modified Hasteiloy N conoining 2^ Ti has good resistance to irradiation embnukment however it remains to be shown that the alloy has sufficient resistance to shallow intergranular cracking Numerous laboratory tests are in progress (o answer (his important question It may be necessary 10 further modify (he alloy with rare-earth niobium or higher chromium additions (o impait heller resistance (gt shallow intergranular cracking
Laboratory programs (o study Hasteiloy N salt tellurium interactions are being established including the development of methods for exposing (est mat era Is under simulated reactor operating conditions Surface-analysis capabilities have oeen improved so that the reaction products in (he affected grain boundaries can be identified
The procurement of products from two commercial hea(s 1000 and 10000 lb I of 2^ Ti modified Hasielloy N continued All products except seamless
tubing were received and much experience was gained in (he fabrication of She new alloy The products will be used in all phases of (he materials program
The work on chemical processing materials is concenshytrated on graphite Capsule tests are in progress to study possible ch-mical interactions between graphite and bismuth-lithium solutions and to evaluate (he mechanishycal intrusion of these solutions into the graphite Since (he solubility of graphite in bismuth-lithium solutions appears to increase with increasing lithium concentrashytion a molybdenum thermal-convection loop that conshytained graphite specimens was run to study mass transshyfer in a Bi 25 Li solution
Some of the effort during this reporting period was expended in reestablishing test facilities Four thermal-convection loops are in operation in the new loop facility which will accommodate at least ten loops The mechanical properly and general test facility is partially operational but numerous test fixtures remain to be assembled and tests started An air lock has been added to the general test facility to make it more functional and plans were developed partially for further expanshysion of the faclity
51
(x Development of Modifk-d Ha^tclkn N H t McCoy
The purpose of this program is the development of metallic structural material)) for an MSBR The current emphasis is on the development of a material for the primary circuit which is the must important problem at present The material for the primary- circuit will be exposed to a modest thermal-neutron flux and to fuel salt that contains fission products It is believed that a modification ot standard Hasteiloy N will be a satisfacshytory material for this application An alloy that contains y1 Ti appears to adequately resist irradiation embrittle-ment but it remains to be demonstrated that the alloy satisfactorily resists shallow intergranuiar attack by the fission product tellurium Small additions of niobium and rare earths (eg cerium lanthanum) to the alloy abo improve the resistance to shallow intergranuiar cracking and likely will not reduce the beneficial effect of titanium in reducing neutron embrittlement Increasshying the chromium concentration from the present 7T to a value in the range of 12 to 15 may also be beneficial in preventing shallow intergranuiar attack Currently factors associated with production of the 2T Ti modified alloy in commercial quantities are being studied while smaller be-ts raquoe being nude o( Hasteiloy N containing both 2 r Ti and additions of niobium and rare earths These materials are being evaluated in several ways
Two large heats one 10000 lb and the other 8000 lb of the ya Ti modified alloy have been melted by a commercial vendor Product shapes including plate bar and wire have been obtained for use in several areas of the alloy development program Tubing is currently being produced by two independent routes The various product forms from the two large heats are being used to fabricate the salt-contacting portions of two forced-circulation loops
Laboratory methods for studying Hasteiloy N salt tellurium reactions are under development Methods must be developed for exposing candidate structural materials to simulated reactor operating conditions Tests are being run in which specimens are exposed at 700V to the low partial pressure of tellurium vapor in equilibrium with tellurium metal at J00C Other tests involve metal idlundes thai are either added to salt or scaled in cvjcualed quart vus lo provide a source of tellurium Several experimental alloys have been exshyposed lo tellurium and Die extent of inlergranular cMltking was evaluated meiallograpliically hssenli^l In tins prltgram jrc attentate technique for identifying
and characterizing the reaction products Several methods for the analysis of surface layers are under development
Materials that are found to resist shallow intcrcranuiai cracking in laboratory tests will he exposed laquobull fissioning salt in the Oak Ridge Research Reactor TeGen fueled-capsule series Three materials (standard llastelloy Inconel 601 and type 304 stainless steel) were exposed in this manner during the first TeGen experiment and their cracking tendencies closely parallel those noted in laboratory tests in which these materials were exposed to tellurium vapor Fuel pins for a second experiment have been filled with salt containing gt J U and will be irradiated in the i a future
61 DEVELOPMENT OF A MOLTEN-SALT TEST FACILITY
H E McCoy K W Boling B McNabb T K Roche J C Feltner
When the MSRP was terminated early in 1gt73 most of the equipment was reassigned to active programs When the MSRP was reactivated a year later the conshystruction and installation of new equipment were necesshysary before testing could begin Balding 2011 acquired by moving the occupants into a siraquoaller building had been used as a mechanical testing area about 12 years previously and was already equipped with emergency power and air conditioning However numengtus imshyprovements ~n the building were necessary in addition to lb acquisition and placement of new equipment Although all of the equipment is not operational this report will describe the status of the facility
The building is a two-story structure with mnninal dimensions of 50 X 50 It The first floor is quite thick and more suitable for -mourning vibration-sensiiive test equipment The second floor is of lighter capacity and is more useful for offices and supoort activities There are Iwo stairways leadmg lo the second floor hut all heavy-items must he brought up hv an overhead crane which extends from the west side of the building The west wall had deteriorated and large doors leading into llie first-floor experimental area made close temperature control almost impossible An air lock having the dimensions 10 X W ft was added lo the west side of the building which greatly increased the buildings usefulshyness for experimental work An inoperabk emerge- puwei geneialor located in a small building on the cast
52
5
side or Building 2011 Mas removed and the space renovated to provide a small shop area
Figure 61 is a photograph of the west side of Building 2011 The air lock which was added is visible on the left-lurid side The crane lor transposing materials to the second f raquo)t is alsigt shown Figure b2 is a view of tllaquoe north side (ias storage racks the new emergency power generator and tie small shop area I left sulci are evident
Figure raquo slows the equipment layout tor the first floor Some of the equipment in the southwest owne is used by the Analytical Chemistry Division lor detershymining the concentration of oxygen in liquid-metal samples A neutron generator is located beneath the salt storage ar a and is used for oxide activation analyses This analytical capability is quite unique and will likely be maintained The 14 lever-arm creep machines on the north side aie for testing in an air environment the 8 machines in ihe next row are for testing in a sail envishyronment the Ji machines in the next row are lor testing bulln an air envirorment Five strain cycle machines are located in the southeast corner and will operate with
test specimens in j salt enviroiiVrctii Ihe temperature and strain readout equipment is centrally located Sail storage tjclitie and salt charging equipment are used ut conjunctii-n with he tests operating in salt environshyment S
The equipment layout on the second floor is shown m Fig o4 Six deui-Ioad creep machines for testing in an air environment are located on the south wall- The tube-hurst equipment is only partially instiled and lis installation is not considered a high-prioritv item Tie annealing facility consists of en furnaces having vartcux temperature and envingtnmental capabilities A separate laboratory in the northwest corner is used for experishyments involving tellurium llasieiloy N interaciiiws The other facilities on the second floor include offices a data storage and processing area an instrument repair shop and general storage
A view of iome of the 22 lever-arm creep machines for testing in an JH ermionmeni is shown tn l-ig t o and a cl-raquoeup is shmn in Fig traquofraquo All of these machines are in operation The control cabinet shown in Fig istraquo contains tlie insirunteKistion for two creep machine-
Photo 22SC-7S
yen 61 Mollrft-SjH Teraquol Faculty (RmMiof 2011) (mm Ihc wta ale The newly tiHUtrihled Jit lock bulllaquo mi the left
54
iJf JhZ
^bullyr^J^f1
Fifc J Matae-S TMI Ficttljr (Baliinj 2911) fjoraquo the monk ate Feature of interei include the hop area on he tt~ left the emenBencv pronator on the kft o s Morale rack in the center and the newly constructed air lock on the ri$h
iraquo now
I if(raquoraquo Kquipmcm layout for the fir floor of BudJinf ifll I
55
Fig fc4 EqnpncM Iqroat for Ifce Miomd Onor of IwMMg 2011
The frame is of welded steel construction The levei arms have two sets of knife-edge pivots vgt that the weight on the back of the arm is multiplied by factors of 6 or 12 The pull rods and cxlcnsometcrs are curshyrently arranged for testing small specimens having gage dimensions 1 in long by lA in in diameter Pull rods and cxtcnsomctcrs lor larger specimens required for code testing) were also fabricated and can be used in the same machines
The specimen deformation can he determined by the dial gage or by a transducer which measures the deflecshytion of the dial gage shaft This transducer signal is conshyverted to a dc signal by the instrumentation in the bottom of the control cabinet cm the right (Fig 66) and is printed at another location The electronic circuit will also accommodate averaging transducers which will be used on more precise code work The instrumentashytion in the bottom of the control cabinet also has a module for measuring load from a load cell (not shown) which Tils in the bottom on (he creep machine The specimen is heated by a resistance-wound furnace
having a maximum Icmpcraturc capability of I200C The temperature is measured by up to four Chromel-Alumd plusmni accuracy) thermocouples treated at various positions on the ipcimcn gage kngth The signal fron one of these thermocouples is used by the Leeds and Northrup type KO proportioning controller to control the furnace temperature Switches within this unit activate an alarm shown in the upper left coiner of the control cabinet (Fig 66) if the temperature varies more than plusmn6degC from the control temperature This alarm unit activates a local light and bell alarm as well as causing an alarm t gt sound in the Shift Operations Office A second thermocouple is tied to an over temperature monitor (lower left side of control cabinet in Fig 66) This monitor is set 10 to I5degC above the control icmp-rraturc arid will interrupt power to the furnace The monitor must be reset manually The furnace is powered by a solid-slate power supply deshysigned by T Hulton of the Instrumentation and Conshytrols Division The unit incorporates a digital Variac which allows power settings of 0 10 25 SO 75 and
56
FlaquofcS i t f
100 of line voltage Power is pulsed through the unit as called for by the Leeds and Northrop controller
The six dead-load creep machines on the second floor are quite similar to the lever-arm creep machines just described As shown in Fig 6 7 these machines r e not in operation but the construction work is com| iete Since the load is applied directly to the bottom of the specimen the equipment is limited to specimen stresses of about 20000 psi However the frames can be conshyverted to the lever-arm type
Two salt environment creep machines are shown in Fig 68 The frames and control instrumentation are the same as for the air environment machines shown in Fig 66 The primary modification is a stress unit which can be immersed in salt Four load-bearing rods run from the bottom of the specimen to a flange near the top of the frame A rod from the lever arm passes through a seal in the flange to the top of the specimen Thus weights placed on the back of the lever arm place the specimen under tensile stress with the pulling force being transferred back to the flange No rods protrude
far below the bottom of the specimen and a salt conshytainer can easily slip over the stress unit This container seals against the underside of the flange Extensometer rods for measuring the strain pass through seals in the flange and strain can either be measured by a dial gage or a transducer A 4-rn-diam furnace fits over the salt container There arc several openings through the flange into the container for gas lirtes and ball valves for elecshytrochemical probes and for making additions to the salt Figure 6deg shows the salt-creep machine which is in sershyvice The salt raquoas transferred into the pot on the right in the salt preparation facility at Y-12 The transfer pot was placed in a furnace after which the transfer pot and the receiver vessel were heated to about 600degC before the salt was transferred by applying argon pressure to the transfer pot The temperature was stabilized in the creep chamber and a strejs was applied to the test specshyimen
One of the five strain-cycle units is shown in Fig 610 The test specimen is a l-in-OD tube with a reshyduced gage section having a length of I in The tube is
57
Flaquo 6A CkMtmp of two Mr-
welded in place and stressed by a rod which extends from the bottom of the specimen to a piston above the specimen The piston s moved by applying air pressure to either side resulting in a tensile or compressive force on the specimen The specimen assembly is immersed in salt while it is being stressed Extensomeier rods extend through the top flange to measure the strain These rods move transducers whose signals are recorded on the bottom instrument Switches inside the recorder can be
adjusted to change the stress from tensile to compresshysive when the strain reaches certain values The test can also be controlled on a time basis and the strain reshycorded Other modes of control are also possible This type of test is to study the rate of crack propagation through thin-walled tubes of varying composition in the presence of tellurium Installation of the equipment has been completed and test specimens are welded in place The tests will be started as manpower becomes avail-
raquo
ask Thear mdashaAntv war be ased for aftojr and ame precise work w be done oa MTS e war arm to be procared at a later dale
The anai jau colectioa station h oa fLe first lloor (Fig 611raquo The apper part of the cabiaet OR die left cuMtaatt snitches a aiaiial readoat aad a snaje poiat recorder lor leraperatnres from avow one-third of dK machiaes- The haak of Mriicbes ia the top of da rajfct-haad cabinet is for tetecrinc siraia rawerraquo for each
The sna-i tcadaajs faaa each auduae arc priated oat oa oae of the andtipoiai recorders A data
M I is located m the aaodfc of the right-I cabiaet Has rnsmMKM ltai print oat 100 points
oa dK designated Ireqneacy (asaaly I br) This is snf-fcieat capacity to print oat oae teaaperaiare aad one
for each piece of eqai|aarnt Two orjer bulleasnriag stations are located elsewhere on
dK first floor
Ffct7 General
59
The annealing arez sun the second floor I Fig 612) The two furnaces on the lower level have environmental control and are used for short-term anneals Eight other furnaces are used for long-term anneals hi which the samples are encapsnlated
Figure 613 shows a typical area in tne second-floor laboratory wed for tdurtum-HasteBoy N studies The
equipwunt includes a quartz encapsulation apparatus special gradient furnaces for annealing the capsules equipment for measunng gas-metal reaction rates and a general-purpose hood
The ttthe-burst equipment boa die second floor (Fig 614) There are nine test stations with each station
four test |
Fin 68 Close-up of two bullut-eiwuuinwtnt lever-arm creep machines The salt chamber on the left-hand machine seals apinst the horizontal flange and the furnace n raised a proportionate distance The temperature control and strain-measurement instrumentashytion are shown on both sides of the creep machines
60
Ffe 69 Lever-arm jd l imnunmiiit creep NMCJMMS in operation The ult chamber and furnace have been raised calt as transferred by argon pressure from the vessel on the right into the test chamber The cabinet on the left contains switching and temperature readout instrumentation for several creep machines
61
FlaquoIO ChwMip of a a l l ltngtJKinmml strain cycle machine M l amocMni intfnjmvntation The ieraquoi specimen is a l-m-diam lube welded on I he bottom I a rod and un ihe lop to a heavy-walled lube The rod passes through the lube and alicrnaling tensile and compressive stresses are impigtsed on the specimen by ihe actuator (piston-cylinder combination) The instrumentation is used to control and record the sires strain-time history
bull2
F g 61 I The cabmct on Ike left is one of smraf tartowt stations for limptnmn Chrontd-Alumel sensors from seYeral creep machines arc ran to this cabinet The switches make it possible to read each thermocouple individually on the digital unit at tlie lop of the cabinet One point at a lime can be recorded on the Azar recorder The cabinet on the right contains a data logging unit for recording strain and temperature on all the machines on the first door The three recorders in the bottoms of the two cabinets record strain data from a l machines
a
fit- 612 tkotopajk of hcsMltsaag facfvty The two lower furnaces have com roikd argon environments Fighl other furnaces (al noi visible) have air environments and are used for long-lime anneals
64
Fig raquo13- Typical vie of geaoat-aeaaot used to dean salt from jpuiawai tested in a l t amroameati
ettl reactroas The hood on the left is
rraquoraquoiraquo wraquo-raquo
F|g 614 General view of tube-burst testing eqaipment asai lo stress tabular spec ant ni by internal pre ware The front paneli contain only (he pressure-related equipment The furnaces where the test specimens ate located and their associated control instrumentation are behind the pressure panels
65
by a pump with a wear pressure of 14400 pa The pump aad the ass-xiated reservoir cylinders have beea approved for opcratioa aad the iaawaaal test suborn w2l be pat irt semcr oa c ow-pnonty basis
Iiiaatdun efiptens wtfJ be placed oa geinaf a l equipment iato operatioa Longer-term objectives war iadade prucaremeat aad iastaaatioa of an MTS fatigue machine aad possible expansion of the fast floor to accooaaodaie additioaal creep machines
t J PROOJKEMENT AND FAMUCATION OF EXHHMENTAL ALLOYS
T K Roche R E McDonald B McNabb J C Fehaer
bullUI hadwit iaaHeatsafraquo Ti M I T I I I M H I I J N
One of the more promising alloys at present for the primary circuit of an MSBR is 25 Ti modified Hasidloy N Progress has been made in the scale-up of this alloy with the production of two large heats one 10000 lb and the other 8000 lb by a commercial vendor The analysis of the heats was reported preshyviously These heals were used to establish processing parameters for producing plate bar and wire and more recently emphasis has been placed on processing seamshyless tubing Mill products from these heats are being tesed in the general alloy development program and used in the construction of two forced-circulation loops for studying the compatibility of the alloy with fuel salt
As reported previously several fabrication problems were encountered with the first heat (heat 2810-4-7901 or 74-901 10000 lb) in that it was prone to cracking during hot-working operations particularly during hot rolling of the plate However with the aid of Glcebli evaluation tests which defined the hot-working temperashyture range of the heat to be between 1090 and I I77degC plate products were successfully rolled A second prob-leri was the susceptibility of the heat to cracking during the annealing treatment following cold drawing in the production of bar and wire products This problem was partially solved by cither flexing the drawn product in straightening equipment prior to aiiiltjHijat 1 7degC or by lowering the intermediate annealing temperature to nidegc
Because a considerable amount of the first heat wis consumed in establishing processing parameters a
I T K Roche B McNabb and I C FeltrwrMSK Proshygram Semmrmu Pmgr Rep Feb 2 1975 ORNL-5047 pp 60 63
second heal was prodaced (hat 8918-5-7421 or 7S42I 8000 lb) for coavcrsioa to tatang bar and wire The bot-forgaag behavior of das heat was qaite good as confirmed by Cfeebie data which showed a very broad bot-workmg temperature range of 930 to 12600 Approximately one-half of das heat was forged and tamed to 4 Jna-diara bar for coaversion to seamshyless tubmg by the vendor Akoa forged bar 4 X 4 X 6 0 in was produced for conversion so tabiag by an altershynate route The balance of draquoe heat was convened to the folounac products which bat been received o-m-diam bar (630 lb) 05-ai-diaai bar (292 ft) 0J12-in-disn bar (996 ft) 0125-av-diaai wire (405 b) and 0-094-in-diam wire (338 lb)
For making products in the range ^-ia-diam bar through -in--diam wire forged bar was hot roBed to about I-ia-diam bar and an attempt was nude to conshyvert this material by cold drawing to final sizes with intermediate annealing treatments This routing proved satisfactory unti a H^meter of 0J95 in was reached but annealing cracks as experienced with heat 74-901 were encountered to some degree during processing of the 03l2-tn-diam bar and the wire products For example during a run involving about 850 lb of stock about 2 of the product was lost due to cracking during annealing after the material was drawn from 0J95 in in diameter to 0 J i 2 in in diameter The bar was mechanishycally flexed prior to annealing a technique used to minimize cracking in material from the first production heat of the alloy (heat 74-901) The annealing cracks were observed to run parallel to the longitudinal axis of the bar Examination of a transverse section of the cracked 0Jl2-in-diam stock showed that the cracks were intergranular in nature and up to 0065 in deep in the section examined (Fig 615)
It has been possible to reproduce the annealing crack phenomenon on a laboratory scale Samples of 05-in-d am bar of each of the two production heats were coiJ drawn lo 0395 in in diameter (37 reducshytion) and annealed at I I77degC Heat 74-901 developed longitudinal cracks heat 75-421 did not These results are consistent with the vendors observation that heat 74-901 is more susceptible to the cracking problem Since the cracking can be reproduced or a laboratory scale it may be possible to more fully characterize the problem and define fabrication parameters necessary for its prevention
Of the two routes being pursued for the procurement of seamless tubing one by the commercial vendor inshyvolves trepanning forged and turned bar slock to45-in OD X 05-in wall cold tube reducing (or pilgering) the material in three steps to 20-in OD X 0187-ir wall
66
m
o p A
-O o_ b
o x t o 1 yraquo2
o o-
8-o
yen $ H m d i raquo cocks iraquo ttJU-aL-MMi bat of 2raquo T t - a o M M KasMftty N (hut 75-421) Bar was coM drawn 37- and ameafcd a( I065C Ftdicd with (dyccm rrpa 50x
followed by cold drawing to final sues of 10- 075- 05- and 0J77-in OD X OJ035- to OX)72-in wall This route for tubing production depends upon the efforts of two other vendors one for trepanning the bar and the other for drawing to tlnal sizes The trepanning operashytion has been competed and resulted in six tube holshylows each approximately 6 ft long Each of these pieces was processed through the first tube reducing pass to a 375-in OD X OJ75-in wall (3675 reduction) with no difficulty From this point work was confined to one tube hollow to determine its response to in-process annealing at I I 2 I degC and water quenching followed by further tube reduction Annealing of the hollow beshytween each tube reducing operation was preceded by the annealing of a sample which was then liquid penetrant inspected to determine any evidence of crackshying With this procedure the hollow was taken through the remaining two tube reducing steps and three annealshying treatments with no major problems A few shallow surface flaws did develop but these were readily condishytioned from the product Therefore on hand at present is approximately 24 ft of 20-in-OD X OI87-in-wall stock which will be scheduled with the redraw vendor for processing to final sizes The lube reduction of the remaining five hollows will also proceed
The second route for obtaining seamless tubing inshyvolves hot extrusion of tube shells at ORNL followed by cold drawing to size by an outside source Starting stock was the forged bar of the alloy 4 X 4 X 60 in (Fig 616) The bar was machined into six billets each of which measured 3deg50 in in OD by approximately 95 in long and had a 45 tapered nose for extrusion out of a 4060-in-diam press container through a conical die Two of the billets were drilled 0812 in in ID and four were drilled 10 in in ID to accommodate a mandrel and to allow for a slight variation in extrusion ratio A glass coating which was molten at the extrushysion temperature was applied to the billets and served as the primary lubricant Additional lubrication was provided by Fisk-604 grease that was applied to the tooling Five of the billets were extruded at 1200degC and one at I250degC Low extrusion rales (ram speeds) were used to prevent a sufficiently large temperature increase that the incipient meiing temperature of the alloy would be exceeded otherwise serious cracking could result This problem was encountered during the develshyopment of standard Hastelloy N but was solved by conshytrol of extrusion rate
The results of extruding the l7r Ti modified HaMclloy N billets in the order performed are pre-
67
sensed in Table ftI Fur the first three tube blanks produced extrusions lottf 104 and 1605) die low rale of extrusion caused mandrel taawre d w to ecev I I K healing vf the tooling However ike length of tube blanks obtained with various extrusion ratios and ram speeds suggested that the combination of tooling used lor extrustoR 1604 (extrusion ratio of deg41) with an extrusion speed approximaidy equal to that of extrushysion 1605 125 m sec) should produce a complete tube blank This was die case for extrusions I60K and I6QN In an attempt to reduce the force required to make these extrusions the final tube blank lexirusion 1611)
was extruded a a slightly higher temperature 12501 A rather long length ol good extrusion was obtamed but mandrel fanure agam occulted due to the low extrushysion speed
Visual inspectioK of die tube blanks showed die OO surfaces to be quite good as must rated m Hg 617 wfwch shows the lesdmg end of extrusions I60K and 160V O i dae other hand boroocopic examination ol the IDs by die outside vendor performing the redraw operation revealed flaws winch were subsequently removed by gun iriEing These flaws shown typically in Fig 618 a=e believed tc be caused by inadequate lubn-
m-n
Flaquo l seamless tuctnc
H r ( lt 4 gt M u i r K T i - i N (fecal 75-42 h Slock for ramm bwVt o produce
Tafefc-tl snd raridof n w Mask cxtrwOTMvav2t Timdashnodinnl Nattdby N (beat OTI8-5-Mll|(B
Fxtruuon Die diameter i in i
1603
1604
1605
i475
1625
1475
Mandrel dumcrrr
in)
K IruMt-n Rjm speed ratio (in laquo i i
Force ttonsi
Maximum Running itesuils
0813
JO
0812
114
94 I
1041
15
15
25
1230 l l l l Good 0D surface 22 m of tube blank extrusion before mandrel fadure
l6igt 1100 Good OD surface 45 in of tube Hank extrusion before mandrel fadure
12f0 12i Good Oigt suriacc 4raquo in of rube blank extrusiim before mandrel failure
1607 1625 10 941 Stalled operational error
1608 1625 10 941 36 12911 1290 Good Ol) surface 70 in lube Mank extrusion
1609 1625 10 941 36 1290 i290 Good OIgt surface 70 in tube blank extrusion
1611 1625 10 941 10 1000 900 Repeal of extrusion 1607 jtood OD surface 55 in of lube Hank extrusion before mandrel failure
Notes Container diam 4060 in hxtrunon temp 1200deg (except extrusion 1611 at I250C Lubrication class on billets f-isk-604 jcrease on tooling
68
nraquolaquo15M-79
M06
760 Fig 617 Tibr hlanfc exuasjom of 2 Ti-wdifM I fuWuj N (heal 75-421 These are ihc leading ends or the two extrusion
and were photographed in the as-extruded condition
O O-
O O-
O ho d
Fig 618 Typical defects M I the made diameter of extruded lobe Wanks o 7 Tr-modifod rlartcBoy N (heat 75-421) Longtludinal section Ffched wrlh glyceria rejtia tOOx
69
cation during extrusion Therefore several additional extrusions are planned to test ihis assumption and to evaluate other lubricants The bilets will be prepared from the 6-in-diam bar fabricated from the same comshymercial heat used for the previous bitten
The products of the six extrusions (Table 61) were sent to an outside vendor for redrawing to finished tubing More effort was required than anticipated due to several factors the conditioning required to dean up the surfaces of the extrusions experimentation with both plug and rod drawing techniques to establish a workable processing schedule and more frequent and longer intermediate annealing treatments than anticishypated for the alloy The vendor believes that a satisfacshytory drawing schedule has been developed and is proshyceeding with processing of the remaining extrusions The vendors preferred process involves rod drawing and sinking operations requiring about 18 to 2ttS deformashytion per pass with intermediate annealing treatments at I I77C followed by water quenching Quality control steps after each process step irJ-de light etching folshylowed by visual inspection of the OD and boroscopk inspection of the ID for defects It is believed that the yield of tubing from the redrawn ORNL extrusions will be sufficient for at least one of the two forced-circulation loops now under construction
A 6-tt length of cold-worked 075 m-OD X 0072-in-wall tubing was received as product from the development work required to establish a drawing schedule The tubing is being evaluated by nondestrucshytive techniques Liquid-peneirant inspection of the OD showed no defects Silicone rubber replication together with radiographic inspection indicated the presence of relatively shallow crackiike indications on the I D over a 4-ft length Meiallographic examination of a small sample from the did of the 6-ft section showed the defects to be J maximum of 0028 in deep The tube will be annealed and inspection will be repealed including examination by an eddy-current technique In view of the number of process variations to which the tube was subjected in developing a drawing schedule the quality of the OD and that of portions of the ID is encouraging
622 Seimprodlaquoctiontfeatsof2ri-Modified Hastdoy N CoiriaMng Niobium
To provide stock for a more complete characterizashytion of niobiunviiianium-modified Hastelloy N eight SO-lb heals and one 2S0C lb heat (Table 62) are being prepared by a commercial endor Niobium additions lo the 27 Ti modified Hasieloy N base arc of interest for enhancing resistance to tellurium embritilemcnt and
Bve Ni-12T Mo-7laquoS Cr-21 Ti-007 C
l ov Addition of the jadiciied rirMear 4) Heat
laquoze lltraquo
Jmr re Si Ma Nb
Heat laquoze lltraquo
i 10 01 02 085 -115 2500 10 01 02 04 06 50 IO 01 02 135 -165 50 10 01 02 18-22 50
30 50 01 02 085 11$ 50 10 01 - 02 02 085-115 50 10 01 02 05 085 115 50
8 30 50 01 02 02 -05 085-115 50 bull 10 01 02 085 115 50
Indrndnl nines denote maxnnom coaceMnrioa
niobium levels between 05 and 2 wt It w i l be investishygated Ir addition the compositions of four of the alloys were chosen to investigate different levels of the residual elements Fe Mn and Si These results will be important because of the beneficial effects of the residshyual elements upon oxidation resistance and will allow greater latitude in scrap recycle
The nine alloys have been melted and will be procshyessed lo products in the near future The eight 504b melts will be forged and rolled to ^-in-thkk plate approximately 4 in wide This material will be used for voidability salt corrosion tellurium compatibility and mechanic property tests The 2500-lb heat will be conshyverted to t |raquo- V - and | k-in-diam bar products and to a 4 X 4 in round-cornered square bar About half the material will he retained in the last form lo allow future capability for producing additional products of sheet bar and tubing
6 J WELDAMLITY OF COMMERCIAL ALLOYS OF MODIFIED HASTELLOY N
B McNabb H E McCoy T K Roche
Welding at ORNL is generally performed in accordshyance with Section IX of the ASME Boiler and Pressure Vessel Code2 Basically this requires that a procedure for welding a material (or class of similar materials) be developed and that welders demonstrate that they are qualified to weld by the procedure The procedure must
2 ASMt BoHer and Pressure Vessel Code Section IX Qutt ifuvxm Standard for Welding and Braimg Procedures Weldm Bnm end Welding and Brtittg Operators American Society of Mechanical Engineers New Ywk 1974
70
be a written document including die essential variables associated with making the weld and must be backed by test reports including bend and tensile tests which show that the weld is sound A welder can then be qualified to use die procedure by making a weld which is subshyjected to bend tests to show that it is sound This is a very suupKfied view of the process used to develop and maintain high welding standards and the ASME Boiler and Pressure Vessel Code Section IX 2 should be conshysulted for more detal The Plant and Equipment Divishysion main tains a weld test shop under the supervision of D R Frizzed to implement the process and this shop is frequently assisted by the Inspection Engineering Department
Procedures were previously developed for joining HasteHoy N to Hastdloy N (WPS-1402) and Hastettoy N to die austemtk stainless steels (WPS-2604) but it was necessary to demonstrate whether these procedures apply equally weO to 2 Ti-modified HasteBoy N Therefore K-n-thkk test plates of 2 Ti-modified Hastelloy N (vendors heat 2810-4-7901 designated ORNL heat 74-901) were prepared and welded as folshylows autogenous welds with 74-901 welJ wire welds with 2 Ti-modified Hastelloy N weld wire (vendors heat 8918-5-7421 designated ORNL heat 75-421 welds to standard Hastelloy N heat Nl5075 with 2 Ti-modified Hastdloy N heat 75-421 weld wire and welds of type 304 stainless steel heat 18024 with Inco 82T heat NX59I38-D wdd wire Each raquo d d was subshyjected to visual dye penetrant x-ray and metallo-graphic ixr^mation and to two tensile and four side-bend tests These tests were conducted in accordance with die ASME Boiler and Pressure Vessel Code Secshytion IX 2 and ail of the above-mentioned welds passed the tests The tensile specimens were machined from the test plates with the weld in the reduced-section gage length and were tested in a Baldwin tensile machine All Hastelloy N welds exceeded the required minimum 100000 psi ultimate tensile strength except the weld of 1 Ti-modified Hastdloy N to type 304 stainless steel which ruptured in the type 304 stainless steel base metal at 93300 psi The side-bend specimens were A X li X approx 8 in long with the weld in the center and were bent around a I-in radius in a guided bend fixture
The chemical analyses of the various materials involved are shown in Table 63 The side-bend specishymens are li in (luck X hi in wide bent around a l-in-radius mandrel in a guided bend test The specimens were macroetched in a solution of HO 20 HNOj -20 H 2 0 to delineate the weld and heat-affected zones Figure 619 u a macrophotograph of side-tnd specimens of standard Hastelloy N heat
N1-5075 Vi-in-thick plate welded with standard Hastelloy N wdd wire heat N I -S I0 I There were no fiows in the specimens after bending and visual dye penMrant x-ray and mrtallographic examination before bending showed that the welds were sound This weld was inde and tested to recertify the welder and to update the welding procedure specification Figure 620 is a reacTophotograph of side-bend specimens of 2 Ti-modified Hastelloy N (top) (heat 74-901) welded to standard Hastelloy N (bottom) (heat N1-5075) with 2 Ti-modified Hastelloy N (heat 75-421) weld wire by welding procedure specification WPS 1402 There were no flaws in the welds and the strain markings delineate the weld areas
Figure 621 is a macrophotograph of 2 Ti-modified Hastelloy N plates (heat 74-901) welded with 2 T i -modilied Hasteiloy N (heat 74-901) weld wire on weldshying procedure specification WPS 1402 There were no flaws in the welds and the specimens were macroetched to delineate the weld areas Figure 622 is a macro-photograph of the same heat of 2 Ti-modified HasteBoy N (74-901) welded with 2 Ti-modified Hastelloy N (heat 75-421) weld wire by specification WPS 1402 There were no flaws in the welds and the specimens Figure 623 is a macrophotograph of side-bend specimens of type 304 stainless steel K-in plate (heat 18024) (top) welded to 2 Ti-modified Hastdshyloy N (heat 74-901) (bottom) with Inco 82T (heat NX 59138-D) weld wire by welding procedure specification WPS 2604 There were no flavs in the welds and the specimens were macroetched to delineate the weld areas
Although special welding procedures were prepared for the joining of standard to 2 Ti-modified Hastelloy N with 2 Ti-modified Hastelloy N filler wire (WPS 1403) and for joining stainless steel to 2 T i - modified Hastdloy N with Inco 82T filler wire (WPS-2606) the parameters used in making these welds were identical to those used in procedures WPS 1402 and WPS-2604 developed for standard Hasteiloy N Thus we believe that the test wdds adequately demonstrate that stanshydard and 2 Ti modified Hastelloy N have equivalent welding characteristics and that procedures WPS 1402 and WPS 2604 can be used for both materials
Supplies of standard Hastelloy N weld wire were depleted over a period r f time and additional wire was purchased to the materials specifications MET-RM-304B However the voidability test was performed by O R N L Plates of standard Hastdloy N (heat 5067) IV t
X 4 X 10 in were welded with the new heat of weld wire from Teledyne Allvac (heat 9725) using welding procedure specification WPS 1402 and were accepted
71
Jiilln l i s i l
1 3
3 laquo m i a m I z
llllpl liillii s a = c e e v
i
i
I I I
Hill s s = s e
Ii2s I
I bull raquo bull
S C O
33 a c e o 3 O m
i
bull mdash copy o r- d 9gt
laquobullraquo bull gt ampgt ltlaquo rraquo laquo r i mdash
1 laquo
z z z
r t a laquo m r- f 2 gtgtilti bull laquor mdash H-
2 2
i ij
72
Ffcfc1 Bead N(heMNI-S075)j Htmuwwtt SIM)
Ffe gtJ0 I M 4 ffcciMtM of 2 T t - m o t f M HmHtoy N (fctrt 7901) art staataaJ H n M o r N (fcMNI-5075) j o M w M i Tt-modiTM Hartdoy N Mkr win (beat 75-421)
73
F laquo J I (heat 74401)
Ffe 622 ttmt (raquotat 75-421)
of J Ti-motfbJ HMcltoy N (beat 74401) f o M wMk 2 Ti-amtttM
74
FlaquoftJ3 i01 tyyc39v 3 I H T H N ( laquo laquo 7441) j IwMUTflkr
as passing all tests including one all-wdd-inetal tensile test and four side-bend tests with no flaws in the welds This material has been made available for general proshyject use
4 STAWLrTY OF VARIOUS MODIFIED HASTEIXOY N ALLOYS IN THE
UNIRRADIATED CONDITION
T K Roche H E McCoy J C Feltner
The stability of Nb- Ti- and Al-containing modified Hastelloy N with respect to intermetallic predpitation known as aging is being studied It is known that addishytions of these elements are desirable respeclivdy for enhancing resistance to tellurium-induced intergranular cracking for improving resistance to radiation embri-tlement and for deoxidizing the alloy during melting However beyond certain levds these dements can cause aging reactions by the predpitation of gamma prime |Nij(AITi)| or NijNb which in turn causes hardening or strengthening and loss of ductility Therefore studies are in progress for defining the amounts of Nb Ti and Al which can be added to Hastdloy N and still maintain a reasonable decree of stability The stabilities of a number of alloys including laboratory semiproduction and production heat having varying amounts of the
demenu in question are being determined by hardness tensile properties creep-rupture properties and micro-structural evaluation
The first approach to evaluating stability has been the determination of the room-temperature hardness of the various alloys before and after heat treatment at 650 704 and 800degC for periods up to 1000 hr The data for alloys held at these temperatures for 100 hr were reshyported previously1 and during the present period the 1000-hr data presented in Table 64 were obtained he data for alloys which show significant hardening relative to the as-annealed condition are Mocked off in the table
The hardness of the various alloys after a 1000-hr aging period follows the same pattern noted for the 100-hr aging period However the previously reported niobium concentrations of the niobium-containing alloys were low due to an analytical error the correct values are shown in Table 64 The present data show that with low aluminum concentrations (00S wt ) niobium contents approaching 2 (rather than as conduded earlier) can be tolerated in 2 Ti-modified
3 T K Roche D N Braski and J C Felfnrr MSK Pro-gum Semmnnu fmgr Rtp Feb 2S 197$ ORNL-5047 pp 71 76
75
lkra llaquoMi7WMri l
DatamMoriui hatdcMBg rcbthc to the
Icoaditiw
IoapoBtun (laquot ) Rockwell
Heat IoapoBtun (laquot )
AaaeaM (
Agt4 1000 were 704c
hr Nb Ti Al C AaaeaM
(
Agt4 1000 were 704c sooc
474-557 214 002 004 SI 5 S7S SSS S74 472-503 194 009 006 S44 S9S 882 891 474-901 IS 010 006 794 857 S63 856 471-114 1- 012 005 792 829 846 S44 427 24 0IS 0014 747 784 773 779 428 247 016 0064 S25 SS2 861 860 474-533 217 04S 005 Sl0 857 S62 849 474-534 209 053 008 893 925 904 909 429 24 0J5 0017 769 9 4 854 74 430 25
2J 034 074
0073 0016
SS6 7S6
1001 88 9 912 431
25 2J
034 074
0073 0016
SS6 7S6 978 984 928
432 048
235 19
069
008
0057 0037
874
SOI
1034 1034 974 425 048
235 19
069
008
0057 0037
874
SOI 841 858 852 421 10 19 007 0048 873 865 878 867 424 134 I S 010 0063 S84 902 SS9 904 418 192
190 20 18
005 015
0058 0055
891 S87
904 900 9IA
904 420
192 190
20 18
005 015
0058 0055
891 S87 1015_
900 9IA 913
435 142 23 015 004 886 1050 1021 903 43S 180 24 013 005 918 1066 1051 968 433 189 2 2 033 0024 848 1043 1021 881 434 186
252 2 bullgt
22 032 015
0061 005
933 931
1070 1088
103 8 1076
957 441
186 252
2 bullgt
22 032 015
0061 005
933 931
1070 1088
103 8 1076 1041
442 30 22 014 0052 950 1093 1096 1072 30 22 014 0052 950
Bavt Ni l2TMo K Cr l h r j | IMTC
Hastdloy N before aging occurs However the tolerance for niobium decreases with small increases in the titashynium and aluminum contents It must be emphasized thai the hardness data were obtained on unstressed specimens and that creep-rupture tests now under way indicate that lower concentrations of niobium are tolershyable when the alloys are subjected to stress These reshysults arc described Uter in this section
The effect of aging on room-temperature and elevzed-tempcralure tensile properties is being detershymined for most of the alloys Limited room-(emperalure results have been obtained after a 100-hr aging period at 650 and 800degC (Table 65) There is good correlation between the tensile data and the preshyviously reported hardness data As would be expected alloys which age harden during a given thermal treatshyment (data underlined in Table 65) also show an inshycrease in strength and a corresponding decreur in ducshytility relative to ihr solution-annealed condition
In the case of the tiunium-aluminum-modified Hastdloy N alloys the hardening phase is most likely gamma prime and this phase has been identified in heat 430 lt 25^ Ti + 034 Al) after 100 hr at 6 5 0 o C
Stress-rupture results for the titaniunvaluminum-modified Hasielloy N alloys at 650 and 704degC are shown in Tables 66 and 67 respectively Again there is very good correlation between age-hardening behavior as determined from short-term hardnlaquo data and the corresponding rupture life in the stress-rupture tests Abo the effect of temperature upon agmg an be seen by comparing the data sets for heats 429 and 430 at 650 and 704degC At the lower temperature both of these alloys hardened but neither hardened at 704degC Since hardening in these alloys is due primarily to the formashytion of gamma prime these results sugges that the gamma prime solvus temperature is located between 650 and 704degC for these two alloys This observation and the other aging data in Tables 6465 and 66 were
76
Tak6-5 raquo i m l all l i l i h t i i i i i i fci iwfNJ-TVAI
iicbtaKtodK
bdquo laquo t t m t ~ - - - StteaajbUO neat _ ^ _ ^ ^ _ _ _ _ _ _ ^ ^ ^ _ _ l o a a m _ ^ _ ^ _ _ _ _ _ Doaaaboa ()
iraquo r At c mum Y j - i ^ ^ 474401 18 010 00 AnwaM Ikr l 7 r c I MO 442 447 794
Aaoil00br50C 114 J $00 559 SIS Aged 100 brS00C I I9JO SI2 537 151
428 247 0 1 00 A a w a M l k t I I 7 T C 124 J 49-0 52 825 Aged 100 br50C 125J $0-5 527 M2 Aftd l0fgtbrS00C 1237 511 411 M7
430 2J 034 007 Aaneakdlbf I177C I2SJ $00 541 St Aac4IWbr5ltrc 1348 634 437 957 Aged 100 brS00C 12 J 531 $00 886
424 134 I a iO 00 AMtafcdlbr I177C 1372 527 512 Ago i00br6$OC 1385 52J 477 (93 Aged 100 brSO0C 1377 547 45S 199
435 142 23 015 004 Aaaeakd 1 hr 1I77C 12S4 510 54 raquo Aged 100 br50C 190 893 353 1025 Aged l00brSOOC 1339 54-5 S3S laquo73
442 30 22 014 003 Aantakd 1 hr II77C 1394 07 $42 Agadl00bf50C 1905 107 251 AftdlOObrSOCTC 144 ~ J 3 J 1 S 9
bull raquo Ni-12 Mo-7 O
TaMe64 St iwiaptmdashe data for wr iow beats of Nb-Tt-AI R M d M H a s t d b ^ N at 6500 aad 474) x I0gt pa
Heat Composition (wt gt Rupture
life (hrgt
Total strain
Are harden Heat
Nb Ti Al C
Rupture life (hrgt
Total strain at 650deg C
474-901 18 010 006 3950 270 No J74-533 217 048 005 4650 280 No 427 24 118 0014 866 217 No 428 247 016 0064 1150deg 73 No 429 24 03laquo 0017 9572 163 Yes 430 25 034 ftO^ 16980 73 Yes 431 2$ 074 0016 23090 101 Yes 432 235 069 0057 41710 21 Yes
42S 048 19 008 0037 14301 237 No 421 104 19 007 0048 20070J 73 No 424 134 18 010 0063 39530 65 No 418 192 20 005 0058 39550 32 No 420 190 18 015 0055 39510 19 Yes 433 189 22 033 0024 41690 10 Yes 434 186 22 032 0061 39550 09 Yes
BaseNi 12 Mo 7Cr Based on turdnest measurements on aged umircutd specimens Tesl still in progress Test discontinued prior to fracture
used to estimate the gamma prime solvus temperature boundaries at 650 and 704degC as a function of aluminum and titanium concentrations Alloys with compositions lying below the proposed boundaries in Fig 624 are stable at the indicated temperature and those above will precipitate gamma prime
With the addition of niobium to titanium-aluminum-modified Hastdloy N defining or predicting stable comshypositions becomes more complex There is evidence1
that mechanical stress significantly affects age hardening of these alloys which is not uncommon The room-temperature hardness data for annealed and aged specishymens of the various Nb-Ti-AI modified Hastdloy N alloys suggest a tolerance of about 2 Nb in a 27 Ti-0-5 Al modified Hastelioy N base (heat 418) beshyfore aging occurs Further increases in the aluminum niobium and titanium contents lead to age hardening at 650degC then at 70degC and finally as high as 8O0degC when the niobium content is increased to about 25 with 22 Ti and 015 Al (heat 441) If the broad assumption is made that the three elements are equally effective in promoting an age-hardening reaction and a plot is made of the total atomic percent of these deshyments (at Nb t Ti + Al) in the various alloys against the increase in hardness (^RBI caused from aging 1000 hr at 650degC a curve is obtained (Fig 625) A sharp break indicative of appreciable aging occurs between 3H and ^M at 1 (Nb + Ti + Al) Adding the variable of stress to aging response and plotting the parameter of minimum creep rate from creep tests at 650degC and 470 X I0 3 psi (Table 68) against total atomic percent (Nb bull Ti + Al) results in the curve shown in Fig 626 The break now is indicated between 2 and J at (Nb + Ti bull Al) The creep rale of alloys containing up to about 2 at rlt (Nb bull Ti + Al) is 15 to 30 X lO^ h t Three heats (70-835 6laquo-648 and 64gt-344) in the 2 to 3 at ^
region which are high in niobiuro and low in titanium are known to age upon creep testing at 650degC at d exhibit creep rates around 1 X 10Jhr One heat (425) with the reverse combination low in niobium and
4 H y McCoy MSK Program Senu4m1L ftogr Rep Feb 29 1972 ORNL-4782 pp 167-69
30
25
7s- i sm
20
z
z o u
15
10
05
NO y
bull704-C -
650 C
02 04 06 Al CUfTENT ()
08 10
F|laquo 624 PlUMJWa bullOMIMJM MSWatl Sttbfc fan bullraquo-staMr alaquoovs of N i - I raquo M o - 7 Cr bull Al and Ti with remcct to p i M prime precipicslioa m S0 and 704degC Alloys above the lines win form ttamma prime and those below wifl not (see Table 64 for the compositions o f the various alloys I
Tab 67 Stress-njptare data for several Urals of litaMM-almiNMM modified Hastetoy N at 704 C and 3SJO X 10 psi
Ileal Compoutiofi twt bull 1
Ti Al
Rupture life (hr)
Total strain
Age hardens at 704C
474-901 474-5 J J 427 428 429 430 431 432
18 217 24 247 24 25 25 235
raquollraquo 1148 IMS 016 035 034 074 069
006 005 0014 0064 0017 0073 0016 0057
1932 I96 0 820
2018 2006 2124
29383 36115
394 420 234 610 227 558
68 137
No No No No No No Yes Ves
Base Ni I Z Mo in Cr
Result ltgtf hardness measurement taken on ated unsirnsrd specimens
78
7S-1JTraquo 20
raquobull
14
an c
i lt
laquo0
bull433
bull 435 U^TA j raquo44l
438 _Llaquolaquo
420
- bull 4 2 5 -
bull 434
mdash~3poundt^~ 4lt8
25 30 42t -bullmdash 35 40 45
at (NbraquoTraquoi) 5 0
Fij 6 J5 Chante M kmimm ol 1 vanon beats of Nb-Ti-AI-amdiTied Haste N after 1000 kr at 650C (see TaMe 64 lor the coMposinons of the bullMiow alori)
TaMe 64 Coayison of hardness changes4 aad creep beharioi of Hasteloy N moOfttd with Nb Ti sad AI
high in titanium does not seem to show much aging Alloys containing 3 to 5 at (Nb bull Ti bull Airaquoage appreshyciably with creep rates of about I X IO3hr or less
The above results indicate that zlloys containing approximately 25 at or less (Nb bull Ti + All will be satisfactory from the aging standpoint Such an alloy would be represented by the composition on a weight percent basis of 05 Nb-I5 Ti-01 AI Alloys having concentrations of Nb + Ti + AI above the 25 at range will be more susceptible to aging
Future work will include evaluation of mkrostructure for a number of these specimens to confirm present conclusions evaluation of additional alloys to test the indicated boundaries for stable compositions and an extension of data analysis to determine whether a quanshytitative relationship can be derived that separates the relative effects of the individual elements Nh Ti and AI on the stability of alloys of this type
65 MECHANICAL OPERTIES OF TOANIUM-MODIFIED HASTELLOY N ALLOYS
IN THE UNIRRADIATED CONDITION
T K Roche J C Feltner B McNabb
Several tests were completed or are in progress to determine the mechanical properties of recently reshyceived heats of 2 Ti modified Hastdloy N in the unirshyradiated condition These alloys include two production heats (74-901 and 75-421) and six semiproduction heats (74-533 74-534 74-535 74-539 74-557 and 74-558)
behavior of several heat
Composition Hardness Kg Minimum creep rate
Cilhx) Heat wl 1 at Annealed 1000 hi
al 650C Change Minimum creep rate
Cilhx) Nb Ti AI C Nb fi + AI
Annealed 1000 hi al 650C Change
237 103 004 lt005 084 15 x 10bull 63 25 lt00I 013 166 il X 10 181 185 050 lt001 0045 186 31 x 10 bull 69448 195 092 005 0043 255 70 x 10 69-344 17 077 024 010 263 26 X 10deg 70-835 26 071 010 0053 282 60 X 10 425 048 19 008 0037 290 801 841 40 78 x 10 421 104 19 007 0O48 324 873 865 -0 8 13 X 10 424 134 18 01 0063 338 886 902 16 71 x 10 418 192 20 005 0058 391 891 904 13 22 x 10 420 190 18 015 0055 387 887 1015 128 1 X 10- 433 189 22 033 0024 475 84 1043 195 2 x 10 434 186 22 032 0061 470 933 1070 137 3 x I 0 -
Alloys aged for 1000 ht at 650degC and hardness measured in unstressed condition Creep tested at 650deg C and 470 x 10 psi f Base Ni 12 Mo 7Cr rflhratll77C
79
6 OANL-OTN 75-Wtf
5 5 k 433 1 raquo434 | 1 1 iHll
- (
I
gt420 M 1
1 tlltk^
- (
I i i
70 -835 lt i T ^ 1 | U 1 bull 69-648 6 - 4 4
I
1 425
2
1
I II 1 i i |
bull S3
M81 2
1
1 1 1 1 i
1 |
bull 237
I 1
10 i - raquo tor4 2 5 laquo r 3 2 s MINIMUM CREEP RATE 1nr)
10 io-
F 626 MiMam cteep rale of vwkms heals of Nb-Ti-AI-nodified Hastelloy N tested at 650degC aatf 47Jgt x 10 pa (s Table 64 for the aloy coiapositicm)
Four of the six semiproduction heats contain small additions of rare earths lanthanum cerium and miscii metal The compositions of these alloys were chosen to study the effectiveness of rare-earth additions for minishymizing the extent of shallow intergranular cracking Each of the six semiproduction alloys was the prodxct of a 120-lb double-melted (vacuum induction plus elec-troslag remeit) heat produced by an outside vendor The chemical analysis of the alloys was reported preshyviously5 The mechanical-property studies include the determination of room- and elevated-temperature tensile properties and creep-rupture properties in air at 650 704 an J 760degC These data serve as a reference for comparison with the properties of standard and other modified Hastelloy N alloys both in the unirradiated and irradiated conditions
The principal effort during this report period was directed toward completing the creep-rupture data on the above heats Tests are being run at three stress levels for each of the three test temperatures Most of the tests were completed with the major exception being heat 75-42 he 8000-lb production heat for which specimens are being prepared Specimens of the other
5 T K Roche 8 McNabb and I C Kcliner MW flj-gnm Stnimnu Progr Rrp Feb 2 1975 ORNL-5047 pp 61 and 65
heats were obtained from swaged rod and were annealed for I hi at 1177degC prior to test
Figures 627 through 629 are plots of rupture time as a function of stress at 650 704 and 760degC respecshytively for the 2 Ti modified Hastelloy N heats and are compared with plots for a previous heat ^471-114) of the same alloy and standard Hastelloy N Minimum creep rates measured from these tests a the three temshyperatures are shown in Fig 630 as a unction of stress As concluded previously the more recent heats of 29t Ti modified Hastelloy N are essentially equivalent in strength to the earlier heat and there is no significant effect resulting from the addition of rare earths to the 2 Ti -modified alloy As determined from past work and confirmed by the recent tests the modified alloy exhibits longer rupture lives than standard Hastelloy N at the three temperatures
Additionally the first of eight creep machines capable of tests in molten fluoride fuel salt was put into operashytion A specimen of heat 474-533 has been in test at 650UC and 300 X 10 3 psi for slightly over 1300 hr Data are not available as yet on this same heat in air but a comparison is made in Table 69 with an air test of an earlier heat (471-114) of the same nominal comshyposition
The data appear to be falling within a normal scatter band for alloys with the same nominal composition that
80
10 2 5 KT RUPTURE TIME (Dr)
Flaquo 6-27 Sueswuptare properties of several heats of 2 Ti-modified Hastcfloy N and standard HasteRoy N at 650 C I Ranges of rupture strain indicated in parentheses)
60
90
= 40
laquogt 30
20
10
0MH-DWC 79-laquoS7raquo0
[ mdashr-1 i j
- laquo gtlaquo 2 Ti-MODIFI bull0 bull AS El -LOT N (HEAT 4 r i - iu raquo i h t
B ( 39
h 4 -
r
II 6261 r ( 3 7
bullIs
I 2-476) -
laquobullraquo bull (
i
bull 174- 33
1
39
h 4 -
r
II 6261 r ( 3 7
bullIs
I 2-476) -
laquobullraquo bull (
368-47
1 6
A 474-535 laquo 474-539 o 474-557
-STANOARS HA STE
I-
LL OY N
o lt raquo74-laquo
1 L
KM
1 1 TES II
T TEMPER
III ITUR
STE
I- 70 4C
11 V 2 10 tOJ 10 RUPTURE TlaquoE (hr)
Fit 62 Strcavmpfare prupeniei of several heats of 2 Ti-modrTwd HacMfojr N aad staadaid HaateBoy N at 704r (Ranees of rupture strains indicated in parentheses)
81
Tvaoraquo 35
30
25
I- -
11 1 1 1 M IMP i | TT bull1 X I i h i j i i
bull -MODIFIED HASTEU0Y N CHEAT 471-14 -1 i IIIH |
i bull i i i
i gt lt
I i h i j i i bull -MODIFIED HASTEU0Y N CHEAT 471-14 -
1 i IIIH | j
j
j | i i
M 1 nH t t Y-
r 1 i n 1
t bull 1 I t I i |
i i i i i V bull i i bull i bull
raquo 474-533 gt 474-534 i 1 M h i t raquo 474-533 gt 474-534 I r bullv M I f f bull 474-535 raquo 474-539 I M i i i 11
o 474-901
1 Mi l l i i T
1
TEST TEMPERATURE
ill I i BOT
i IN to bull 0 2 2 5 SO5
RUPTURE TIME ffcr) bull0
F i j 6 2 9 Strcss-raptate properties of scleral heats of 2 Ti-modified Hasttstoy N and standard lUiMMoj N si 760C- (Ranee of rupture strains indicated in parentheses)
omn-oac n-tsret TV
f 2 5 raquo - MINIMUM CREEP RATE (hr)
Fig 630 Creep properties of scmsl heats of 2 ft-modified HasteHoy N at 650 704 and 760 C Solid lines arc for heat 71-114 and the dashed lines indicate bands which contain the data for the other modified alloys
S2
T M H -Ac mdash l i i r a s w a raquo laquo 1 l
larl 474-533 471-114 iflaufijc farii ltagt
500 13 24 1000 44 1300 35 55
Tlaquowraquo ion ai 650 C n d 300 x 10 pa
are tested under similar conditions and there is no indication that ronoaon by the molten fluoride fuel salt represents a sgmficani factor
jraquo rOSTIRRADUTIONCREEf MtOftRTIES OF MODIFIED HASTELLOY N
HE McCoy TJC Roche
puurade of the ORR Each experiment contains 102 miniature creep specimens in an instrumented facility in whkh temperatures can be measured and controlled by supplying heat from auxiiary heaters Only 12 in-ceU creep uwrtnim are available for postirradianoa creep testing hence the testing proceeds rather slowly The most recent tests have concentrated on lt I ) the propshyerties of six 125-lb senuproduction nests that contain 2 Ti and low concentrations of rare earths and (2gt the properties of several alloys containing both niobium and titanium
The results of tests completed to date on the six heats that contain titanium and rare-earth additions and the (OjOfXKb commercial heat that contains titanium are summarized in Table 610 Previous tests at temperashytures of 6S0 and 704degf showed that the creep propshyerties of these heats are about equivalent The rupture nfe at 650degC and 40JO X I 0 3 psi varied from 1200 to iSCC hr and the rupture life at 704degC and 350 X 10 psi varied from 170 to 200 hr Final conclusions con-
Postirodtion creep tests are in progress on specishymens from five experiments that were irradiated in the
6 T K gnmSemm
Roche i ( l-dlner and B McXabb MSK Pro-mm flop Rep Feb 2 1175 ORNL-5047 p 7
a t 6 S r C a r laquo s a o M n i atUttMecatca
ABojr Ten mantel
Irradiation tcmpcniafle Si ecu
(10 pa) creep rate
(hr)
Rapawe life (hrgt
Total fracture straia Cufaycailioa (gt
474533 R-I9I2 R-190
R-I929
650 650 7ltK 760
400 470 400 350
0025 0050
0035
2311 I I I 5 2
2022
72 217 Ti 04 At 7 6 4 7 J
474-534 R-1913 R-1909
R-1930
650 650 704 760
400 470 400 350
0021 007
0008
5722 660 5raquo 7 3
16 2 209 Ti 0 J 3 Al 001 3 La 69 35 28
474-535 R-I9IS R-I9I I R-1922 R-1926
650 650 704 771
400 470 400 350
0016 0099 0023 0019
7 6 M 930
4677 6454
1V6 2 1 3 Ti 055 Al 004 rare car TS
123 139
474-539 R-I9I4 R-I9I0 R-I92I R-1925
650 laquoS0 713 774
40 JO 470 400 350
0020 011 0C3I 0000
601 739
4295 12200
108 193 Ti 020 Al 003 Ce 97
165 114
474-557 R-1920 R-1923 R-1927
671 713 771
470 400 350
0045 0044 0019
2174 162 434S
1 0 214 Ti 002 Al 95 S3
474-55 R-I9I6 R-1924 R-192
650 716 795
470 400 350
0X192 0021 0012
1793 475
79 205 Ti 0-02 Al 002 U 6 II
474-901 R-1936 R-1937 R-1907
650 70laquo 732
470 470 470
0069 015 014
1716 332 525
1 3 10Ti00Al 52 1A
AD specimens lancaM I hr agt 1177C prior (o irradiation for M 100 hr to a thermal thence of vlt3 x 1 0 neutronscm Alloy nominal bast composition of Ni 12 Mo 7 Cr -005 C
S3
cerning the postinadiation properties (Tabk 610) are not possible because the tot matrix ha not been comshypleted Specimens irradiated at 650degC and tested at 650degC hare rupture lives that are about half those of the unirradiated specimens but there are no differences in the properties of the various heats that are considered significant in view of the limited data The properties of afl heats are considered good after irradiation at 650C After irradiation at 704degC and testing at 650degC and 400 X 10 pa the rupture lives of heats 474-533 and 474-534 appear to be lower than those for the other heats by a factor of 3 In afl cases the rupture life and the fracture strain were lower after irradiation at 704degC than at 650degC After irradiation at V760C and testing at 350 X I 0 3 psi at 650C the rupture fafe varied from 43 to 1220 hr and the fracture strain from II to 114
respectively Thus differences in creep behavior of th-se aftoys likely become progressively more important as the irradiation temperature is increased
The fracture strains of the various heats appear to show significant trends with increasing irradiation temshyperature Heats 474-533 and 474-557 have good fracshyture strains (6 to 104) which do not decrease apprecishyably with increasing irradiation temperature The fracshyture strains of heats 474-535 and 474-539 are i t the range of 10 to 16 and do not change appreciably with irradiation temperature Alloys 474-534 and 474-558 show decreasing fracture strains with increasing irradiashytion temperature The behavior of alloy 474401 appears to be unique in that it shows a marked drop in fracture strain as the irradiation temperature is inshycreased from 650 to 704C However this effect may
Ta t 611 bullMtffiall rNamwsaKsrc
Alloy Test HftlhCT
Sims HO psi)
creep rale
Rapt me ate lthrgt
Total fraclarc sin in
rfhraquogt
Rapt me ate lthrgt ltgt
428 R-1948 470 0043 2221 119 474-533 R-1908 470 0050 I I I S 78
R- I9I2 400 0025 2311 72 430 R-1947 470 lt00049 9720 4 8 r
432 R-1946 470 lt00005l 9720 0SC
431 It-1945 470 bullCO0024 972f 424 R- I9 I9 350 Mraquo 3160
400 000024 1406 470 000033 4526 550 00066 9494 78
424 R-1944 630 00096 3554 104 420 R-I9I8 350 bullM) 5322
400 -v-0 1405 470 000021 4509 550 000037 6959 630 000080 3343 700 00062 2776 4 3
420 R-1943 630 lt000l7 10680 18 418 R 1917 350 000002 6514
400 000007 1406 470 000014 4523 550 00040 7948 54
41ft R-1942 630 00022 5592 72 434 630 lt0085 129 II 433 R-1949 630 lt0 00 l l 6600 075
AN specimens annealed I hr al I I77degr prior to irradiation Irradiation carried out al 650C for approximately 1100 hr to a thermal flaencc of Vraquo x 1 0 neutronscm See Table 64 for detailed chemical analyses Test still in progress Stress increased on the same specimen in the increments shown
S4
tt12 laquo T SIMMS CM
AcebaMk maibS0CbjMlaquotoi rtniliij1i4
CoMBoanmi iwt rt Co H o
lOOObraMeal
ctccp cveep behavior
bull S O T f o r V I I W b f 4
CoMBoanmi iwt rt Co mdashjn bullnn a m t H o
lOOObraMeal
ctccp cveep behavior
bull S O T f o r V I I W b f 4
Nb T i Al Nb bull Ti bull Al
428 No No No 247 Olfc 357 474-533 No No No 217 laquo4t 3 raquo 2 430 Yes Yes Yes 2J 0 J 4 492 432 Yes Yes Yes 235 0Alaquoraquo 4 A 3 431 Yes Yes Yes 25 074 4 9 424 No Yes Yes I J 4 I S 010 33 420 Yes Yes Yes 10 I S 015 3S7 4 I t No Yes Yes l laquo 20 005 3 1 434 Yes Yes Yes iaraquo 22 032 470 433 Yes Yes Yes l laquo 22 033 475
Sec Tabfc 1 4 for c l e t M e U t f e M U analyses
F I O M Table 4 rFroaraquo Table t A based ltM ctmatemiomt of data i ON novate Me aMl total u n a rfFrow Table 611
be related to the strain rate a summary these sparse data sanest that the fracture strains of alloys cow-taming only titanium and those containing titanium plus cerium remain at adequate levels as the irradiation temperature n increased while the fracture strains of the two alloys (474-534 and 474-558) that contain lanshythanum do not Additional specimens were irradiated and tested to check tins important poatt
Section 64 of this report deals in detail with the metaOurgical stability of alloys containing Nb Ti and Al in the unirradiated condition Some of these alloys have been irradiated and limited test results are availshyable (Table 6) The alloys were annealed for I hr at 11770 prior to irradiation for about 1100 hr at 650C The anneal at 1177degC should have dissolved most of the alloying dements and the subsequent period at 650degC may have resulted in the formation of gamma prime Precipitation of this embrittling phase abo strengthens an aBoy hence the postirradution creep tests should show whether significant quantities of gamma prime were formed As dacussed in Sect 6 4 precipitation of bullhis phase may be strain induced and a detailed analysis of the creep data wSI be required to determine whether the gamma prime formed m the specimens during irradishyation or whether it fonrvf as the spedmens were stressed initially
The data from Table 611 and information from Sect 64 are summarized in Table 612 which shows that the
conclusions are reached with regard to aging of creep specimen in the unirradiated and irradiated con-drtions However hardness measurements on unstressed umrradaied specimens fail to be a good indication of agt in aRoys containing nioHum Alloys having a com-tlaquoKd titanium and aluminum content as high as 357 at had excearnt postirradution properties ABuys with higher uimbimd concentrations are quite strong Kut no conclusion can be made about their fracture stains All of the alloys containing Nb Ti and Al are quite strong and can lake considerable strain before fracturing ABoy 434 has a low fracture strain waste no conclusion can be drawn relative to ahoy 433
The alloys containing Nb Tiand Al which have been evaluated thus far are likely too highly alloyed even though some of the fracture strains jre acceptable Less highly alloyed materials are being irradiated
67 MlCKOSTRUCTURAL ANALYSIS OF T i T A N M M I O W I E D HASTELLOY N
D N Braski J M LeMnaUr G A Potter
The first part of this section presents the results of microstruclural studies of two titanium-modified Hastefloy N aloys 472-503 (designated 503) and 471 -114 (designated as 114) Previous analyses of these tame two alloys dealt with their nricrostructwss after
bulls
afmf aad after postsrraanrtion creep tests In the pressai m f j i l f the nacroairaciaret ot hutfcaftoys were analyzed M an attempt 10 explain some w u l pouarsdanoa creep teattts M sptoaaas that were pven a ltjfgtrtj higher soratiua aaaeahnf treatment Move trratmttian I V mdym showed that many at the wlaquo ipninsrai owe t f i e mhumimracnni and that tkc poor creep properties ttiaMmsonsr cases tie related lo the iahomimnKitsti D M ftnamg prompted a sindy aanei at iiiiidwiag asm hinaimiatimi llamllin N aloys The problem if betw approached by rcdactae it carbon coateat of the anoy aad by gnaw carefal attention ID the tahjicatani pmmHcn The resales ot taaml narranrnti to tnWicalt hiaanpariita alloys arc pKsvnacd m BM secoad part o( thjis section
471 M f u m i r i a i J M r laquo f JkaaysSISamllH
rVanmnaaaaa O H I I o n The retails of creep ten o specimen of ahoys 503 aad 114 which had keen PKVSUmdash)y irradiated in the ORR al 7a0C Me given in I hgt 6 J I The creep tots wete contacted at 6501 n a turn and of 350 X I 0 3 pa This partwalar scots laquoraquof spnameas was designed lo show mc effect of tobmoa anatjbni remperatarc on the postkravniion aeep rop-r-re We of the naieriah The solation anneal was a I-hi heal ireainieM and was given lo all sprcimens before ikes were irradiated 4 men in Fig 6 J I ibe 503 speci-men given the standard I br at 117 ( solation anneal demonstrated food creep iiipiwic We wbifc the 114 tprvmen given the amc ircaimenl had a comparably short lifetime However with an mcrease of only ^30degC in aim latins temperature ahoy 503 had a freatty reduced lifetime wMe ahoy 114 thawed marked improvement It wn corasdered ankkety that tkese rendu coaM he canted by changes in solution anncaing tcmpcrainre alone and other posabh cxpla-aatioas were soajbl It b important to note that despite the apparent mtfaMiiy in creep behavior the properties of the 2 Ti modified alloys arc gencraiy food The problem is that lo determine why tome specimens have poor properties A bullohtlhm to this problem was sonjht by carrTafly anatyimf the microttrnctnres of the two alloy 503 and 114 tpecrmens described above
7 D N bullgt I M UMmfccr jml f i A Puller JfSff AOBVM Semtmmm ffngr Hep Am J I 174 OHm-5011 pp 2 M
n I) S Hrai I M Inraoker j J ti A fnwr 10ft rtomm Semtmmu hop Htp Frh 197 ORNI -5047 Pf i vn
am-a t-laquotlt H 0 O ^
snvss ifwfi bull raquooooraquot
llaquo00 i bull ~ i
bullooraquo 7 1
SOI I
1 z- 2 aosf tr
w r T~iHr-wV---
eoo^mdash mdash mdash - 7 - l V mdash ^
laquoooo tlaquooo laquotoo laquoJOC tOkwtio mntauvs rtanjntTtM ltKgt
Hattys SWanf IM at wfTC ahw Irmthmm toOU wr laanm
TtasmnJtvJmi eltclnm nncrattwny Samples were preshypared for iransnaanoa ekciron nacroscopv iT lMi bgt elevtropohaaaf small transverse sections a( the tested creep specimens in perchloric acid sohrtions Frfures tgt32 and 6J3 show electron naaofrapbs repteseniattvc laquogtf 503 and 114 specimens respectively Hfare tgt32 shows an area near a frain boandargt in the 503 specishymen annealed at I I 7 7 C The nacroHnictaie was obshyserved to contain NT-type jwkaiii both in the ftsin bnandiry aad m the form of tmaH ptattieis DMoca-lions were nearly always foond to be aawoMcd raquotih ike MC plasestis The 50specimen anaeaWd at iagtraquoC had ssaabw featarn laquoFsg 6-321 In both speenneas ibe MC pbielets were coaccntrated near the grain boundshyaries This tajfrsts that the element or elements (probshyably titanhan) awimf ap the MC-type carbide in both specimens wete not anifonaty dittrrbwted ihroafhoat the ntntrix Rfare 6JJ shows ehxtron araquoao|raphs of ike 114 specimens aaaeated at II77C(Fig6J3tand I204f (Fhgt 6J3raquo These specinwas also contained tine hJCMype cjrbidei bat aalwd of formmf pbtekts they precipitated oat on stscUnf faalu The suckmf fault precipitates initiate from iaiocstioat aanriaUd with preexitlmi or primary MC carbides and frow atom ( l l l l pbmrs The primary bX carbides (the dark
9 J si raquotVudt j4 raquo ) IWHUM PariHl Praquogt^i-raquolaquo
FfctJL iirrcraquogt
IMi to to ON m C alaquo r c w i laf I fct laf ItonlSMT
FfcUX 11 rrr laquoraquoMMMI~
bullraquo laquobull IH aft i 4rflt ifctMijarr
bull7
bullJS maunutj I t 93 n r r r IFBJ 6jlaquoaraquo a hai laquobull
face ocal oadu laquo laquowieau of
I M laquo F v J 4 laquo ^
f i W t laquomajm awir loaae Iraquoraquo bull ulaquoaagt aavm tar rmttte mctmm of tar Maaak TW laquoaraquo-hlaquoir i i i i f m mt omtfutd raquoH w w n n MC-fraquoar pat-iarraquo atad ar m bar pml r i nraquo the | bullveil) at fafencaiMa)- Suit aifcaiettfaiamare i loth atatuicw M Fa 6J6 bgt the iafJMf t laquo mdashlaquopmm ukra gt4 oW 503 aajdaara 1W 503 laquofrltMMraquo J M K J M j i I5M C hai oaka iem tracks Ifiy 634raquo| feat laquoa a lacat arja aaaarealh Me to
ka4 a sfcvrt crer raatare life aha M a ^bullXM2laquo4hKk m l Mi fit my (filaquo J5 IL K M -
bullera m mm Sm mtomm (Fftj J4raquo|i h mm akv I thai aartee aacks bull jraiar fiw layer TW 114
I2MdegClaquoFlaquoJ$raquo)lt
the tenet 509 aaaatn (Fig 3Saraquo Hat layer tana) a e 53 mm 114 air-aafi
aa ie i t jn at II77C ai anjon
baen of i l aaa ltA0J raquo ) a w u t e m I at aacoad 617 after OlaquoCP tern at I W f C raquooraquo i r at bullraquo M a a OI I I I i n 500 pmm oBjaea- T V bet of cartwtci ai tar tarface lever any teae at tarn
in I U a laquoN1 i fcc ~ IW f f v i olt bull m bullbullbull ngt bull mp ttaatmdash ftuauwt l laquo a i i rlaquoWKftll~l raquofJaar 1731
617 M
+rnm
OTraquomm
ttm mOtOimTttrc am IMtMTC
growth m the 503 specimen (Fig 6 35| during the soMMwa mmtd h is Midear as to
certain tptcimrai haw the carbide-free layers 1 specimens were svoposedry fabricated in the
same way The malts of the mrtafcajraphtc and TBI lt
lion cannot be nsed to fnty explain the i which led to the early creep fnlnrc of two of the specishymens studied However we banc shown that a awnber of aticrostractaral inhoniofmirties exist in the 25t Ti asotified rLarloy N aftoys induding carbide-foe sur-face layer tnrft-grsia lint snrface hyers nmeratwd carbide strinnprs and nononifonn diHribniions of Mf-type carbide nor grain boundaries Some of these
ties appeared to affect the resnhs of tots and may also inflnence other hnpor-
snch as those renting to tclarium attack Consequently a stndy was initialed to prodace rtsstd-loy N aftoys with more homogenous nacrostradares
bull J J llinnnmiim UnmfJy H Aiayraquo
The problem of prodacing Hastdoy N alloys with hiuaugtmuui nacrostructures is being approached in two ways The first is to reduce the carbon content in the atoy to ensure that aR of the MC-type carbides are diaailvud daring the solution annealing treatment If all
the carbides could be held in solution daring fabricashytion the formation of carbide a ringers might be eKna-aated The second approach b a detailed evaluation of tbt fabrication process This latter effort is prwmily
at identifying the steps at which the different ae introduced and finding suitable
akemate processing methods to remove the anno-anajftiti A definite concern throughout the entire study is that any successful fabrication changes also be
immmiil practices The first series of experiments was
to cmnJnate carbide stringers by reducing the carbon content of the ahoy Thermodynamic takula-tions aung data from previous experiments indicated that aN of the carbides should dnsorve at I I77degC in aloys with carbon contents of less than OA45 wt 7 Therefore two aloys 451 and 453 both wtth a nomishynal lauteaoy N convocation (13 wt Mo 7 gtt Ct bal Ni) and 144 wl Ti were cast into l-m-omm marts having carbon contents of 0017 and 0035 wt 7 respectively The fabrication schedule called for the cast ingots to be hot swaged at I I77degC from a I-in to a 0430-in diameter and then to be annealed at I I77degC for I hr The rods were farther reduced o a 0 J37-in diameter by cold swaging annealed at I I77degC for I hr and cold swaged to raquo final diameter of 0250 in One-inch-long samples were then cut from each alloy rod
bull 9
encapsulated in quart urJer an argon atmosphere and aged at 7G0degC for 16-5 hr to precipitate the carbides After aging the carbides in alloy 453 (0035 C| were extracted clectrochermcally in a methanol 107 HC1 solution Consecutive extractions produced the profile shown in Fig 6 J 7 of wt 7 carbide precrpiuie through the thickness of the sample The profile for alloy 453 is considerably more uniform than those obserad for alloys 503 and 114 specimens aged at 750degC for 1000 hr The difference may not be entirely due to a reducshytion in carbon content because the 503 and 114specishymens were swaged from bars cut from i-in-thick plate not from drop-cast ingots (Carbides are fairly unishyformly distributed in the grain boundaries of the 2-lb laboratory ingots while they appear as stringers in the A-in plate) Meiallographic examination of the aged 451 and 453 samples (Fig 6 J 8 ) showed that the reducshy
tion in carbon content did not ehrninafe the carbide stringers However the stringers were liner and more evenly distributed than those observed previously (Fig 6J4o) Carbide-free surface layers were observed in both specimens a typical surface layer in a heavily etched 453 sample is shown in Fig 6 J 9 The depth of the carbide-free surface layer was V0U03 m
Fatifcpnwn One of the moat critical steps in fabrishycating tbtf^iioy N aRoys with respect to its effect on microstruciurr laquo the solution anneal Electrochemical extractions on an as-swaged alloy 453 (00353 Cgtsamshyple showed that a moderate number of carbide panicles (M) 2T) was present Hi the microstructure after procshyessing It a suspected that the sample was not adeshyquately annealed at 1177degC prior to the final cold swagshying operation That is the annealing lime was too short or the annealing temperature was actually less than
90
0080 O0TS FMQHOWTEtOF
X amy Mkif S03 JI 1177 f M lt jpee gti laquocopylt for
I ITTC Therefore the respuMe of tiUmum-mudifWd thneloy to sohnion aaandias at I I77degt ws stmfced as a fmctioa of time at temperature
Samples of aloy 451 |OJOI7 Craquo W anon at I IT7degC for 15 mm lo hr The cleaned etectrucheaacaRy for 6 hr to remove any nr-faoe effects ami the carbides were electrochemical extracted separated ami weighed The resatts of this experanent aw plotted m Rg 640 (My extremely
bullis of prcopitaies were present a samples for 2 hi or more At times less than 2 hr there
scalier m the data hat m geaerai chfHIv preopifc te was extracted These remits indicate
that JO to 60 mm are weeded m addition to the stanshydard 14 sohtiox anneal at 11 T T r to dtooKv the carshybides completely Muumaptu of tectioas from each of the samples r f aloy 451 from the first jaarmaj series are mown irgt Fig 641 Little gram growth was omened between the 154am and 14v anneals while mgbt grain growth was etideai after 2 hr at II77degC As expected rather extensive growth occurred at the longer j times of 4 and 8 hr
FfcnJB Wcwsmnmwof limn wimfml llsmliy N amyi451 jM7Cgt anl 4raquo IftWW O after coal maawwanl aanf at TMTCfbr I US fcr (laquogt Alloy 451 laquoAgt AHny 45 J
91
foert seed-
Abhoaeb most of ike effort m ties stedy hat beea pit wii be exammed mdashtuiognfkicjh before deeded towvd etmeeetioa of canede miegrn a the aflaquoer a soaatioa aaeri at 1177C I b j bull a bullloys enprrimdashrii aieafao mdashdet way to i i i f i i a n the iimiag eomt a t e mdash taebidr few b y m cjHeoftie carbide-free layersm oar experiment Bee- alnae ibr mdenrd irrliw nf
a w that n any effects of bet or cob) Y-133201 mmraquobemremoeedby
there is ike coaaderata eery bull fact be the bey to uioootaH a ahoy A aoajher of rchmvesy eeeor cheaats bull the way ibe eeecviel is leeeeed amy mwe oaaaaptK effects oa
4SI awi 453 aie ui l i l l aai wal be tnMcated to CiVideraquofiw]|Bmemmmmmmmmmmmmmml 025ampmemai rod with special attewtioa peel to the
CSl nOwal t h e W O f k HBOC l lHOWHKNVt the B I O O 0 B H K SO
J SALT COMtOOON STOKES
J R J R Difdkno E J Lawrence
by of
FbgtraquoJ9 i t u n a
453
The conoaoa of bow) asefcei-mniten ihtonac salts has ben the research for aemy years Resell seen as FeFj NiF and HF in the sah react with con-sliteeats of the alloys bet corrosion from these soartes a basiled by the seppiy of reactaets The strongest oxidant of the normal coaetiteeats of foH salt is UF 4 and of the major coastrteeets of most iron- am nkfcei-base alloys cbrommm forms the most stable fleoride Coaeeoeeetly the major corroajon reaction between
02 OftftJL-OWG 7 5 - 1 2 2 4 )
5
imdashimdashimdashr o 1st ANNEALING RUN laquobull 2nd ANNEALING RUN o 3rd ANNEALING RUN bull 4th ANNEALING RUN
2 3 4 5 TIME AT 1177 C (hr)
FfeSvMl AmcmMoliBAim$9tncmihomraquonor4Slmraquotmgtctomlt4Vmmmitioraquo
8
bullfii7rc
92
to) CM ltlaquogt
FltMI MkioaMjai of mdash bull I br kit 2 br laquoraquobullraquo 4 br jfld if) nr
i laquorf raquo r 451 aftw M M M Mlirrcfcw tol IS i ltraquogtMl ltrgt
nickel- or iron-base alloys and molten-salt reactor fuel salt has been found to be
2UF 4(dgtCrfc)^2UF(draquoCrFj(dgt
Because the equilibrium constant for this reaction has a small temperature dependence temperature gradient mass transfer can occur and results in continuous reshymoval of chromium from the hotter sections of a system and a continuous deposition of chromium in the cooler sections
The experiments described in this section are being conducted to determine the corrosion rate of various
sall-afloy systems under controBed test conditions The variables include compoatiou of the alloy oxidation potential of the salt temperature and exposure time Afl loops incorporate electrochemical probes to measure the concent ration of uranium and transilion-metal flushyorides The systems used to conduct these experiments include one forced circulation loop operated by personshynel in the Reactor Division and three thermal convecshytion loops Five additional thermal convection loops have been constructed and are being prepared foi effrj-tion The status of these eight thermal convection loops is summarized in Table 613
93
i l l l f lS
IA
raquo
raquo
tit
MRSkr
l l t e M JS
rN
it
h i
M l
laquo J I Fael M l
Two thermal convection loop NCL 2 IA and NCL 23 have been operating with M S W fuel salt iLiF-BeFj -T lr f^- lF M M 1 7 - O J mote ^raquo lo obtain baseline common data NCL 21A is a HasieOoy N loop with specimen of the same material At with a l thet-mal convection loops dghi specimens are inserted in the hot and the coid legs The 16 spedmens are reshymoved periodicaly for visual examination and weighing The results of the weight change measurements are shown in Fig 642 The corrosion rate of the hottest specimen in this loop is somewhat higher than has been observed in other rfasteUoy N systems (see Sect 682 discussion of FCL-2bgt The higher corrosion rale of loop 21A relaies to the relatively high oxidation potenshytial o( the salt in this loop ( U M about 10 I Horn-evei assuming uniform removal of material the corshyrosion rate of the hottest specimen was 024 milyear which is within acceptable limiis This loop will conshytinue to be used lo obtain corrosion data for Hastelloy N in kali with a relatively high oxidation potential
Loop NCL 23 is constructed of fnconet 601 and has specimens of the same material A loop was built of tnconel 601 because of this afieys resistance to grain boundary penetration by lefuriwn Since the alloy conshytains ZV Cr there was concern about its ability to resist attack by molten fluoride salt The corrosion rate of Inconel 601 in fuel salt was determined from weight measurements of the 16 spedmens of loop 23 and the results are shown m Fig 6 4 3 All specimens lost weight and the lost shown by the hottest spedmen w very large The material lost by the hottest spedmens did not result in uniform removal of the surface but resulted in the formation of the porous surface strucshyture shown in Fig 644 As shown in Fig 645 electron microprobe examination of this spedmen showed high thorium concentration in the pores The only known source of thorium was the salt which contained T h F 4 so it is very likely that the salt penetrated the pores Continuous line scans with the microprobe indicated a depletion of chromium near the surface Figure 646 shows the results of analysis for Ni Cr jnd Th This figure clearly shows the chromium concentration gra-
94
OMK-WH TO-IZZ4 1 1 1
0 laquo000 2000 JJ00 4O00 5000 SPECIMEN EXPOSURE TINE ltgt
Flaquo 642 Welaquoht campMfts of HasteBoy N p-ciaraquoeas fro loop NCL-2IA exposed raquo MSMt fad o k at the indicated tenMcnaMe
0OM-0VC T raquo - t laquo laquo 5
SPECIMEN EXPOSURE TIME (Hrl
F 643 Weht changes of Inconei 601 specimens from loop NCL-23 exposed to MSBR fad salt at the indicated tem-peratare
dient and provides further evidence of the presence of thorium in the pores Deposits such as those shown in Fig 647 formed on the specimens in the cold leg and the deposits were identified by microprobe analysis as chromium This compatibility test of Inconei 601 in MSBR fuel salt shows a relatively high corrosion rate and it is doubtful that this alloy would be suitable for use in an MSBR under the conditions of this test
The lower limit for the U ^ U ^ ratio in an MSBR will likely be determined by the conditions under which the reaction
4 U F + 2 C i r 3 U F 4 U C 2
proceeds to the right Because the salt in loop NCL 23 is strongly reducing with a U ^ U ratio of less than 6 it was decided to try to reproduce the results of Toth and
Gilpatrick1 wiuch predicted that at temperatures below 550degC and VV ratios below 6 the U t would be stable However graphite specimens exposed to the salt for 500 hr did not show any evidence of U C 2 The specimens used were made of pyrolytic graphshyite and it is likely that the high density of the material limited contact of the salt and graphite The experiment is being repeated with a less dense graphite
682 Fad Salt Forced Gmriatioa Loop
Hastelloy N forced circulation loop FCL-2b has been operated during this reporting period to gather baseline corrosion data under conditions where the i r U ratio was relatively low (see Sect 23) Eighteen itastel-loy N specimens were exposed to MSBR fuel salt with a U 7 U V ratio of aUut 100 The specimens were reshymoved at predetermined intervals for visual examination and weighing and the weight changes are shown in Fig 648 Six specimens were held at each of three temperashytures 704 635 and 566 eC Of the six specimens at each temperature three were exposed to salt having a velocity of 049 msec and three to salt having a veshylocity of 024 msec No -ffect of salt velocity on the corrosion rate was found so each data point represents the average weight loss of the six specimens The weight loss of the specimens at the highest temperature correshysponds to a uniform corrosion rate of 011 milyear Uniform corrosion at this rate is acceptable and well within the limits which can be tolerated in an MSBR
Following termination of the ^3200-hr corrosion experiment FCL-2b was to be used to make heat transshyfer measurements This operation has been delayed because a salt leak developed and a section of the W-in-diam Hastelloy N tubing had to be replaced (see Sect 23) Examination of the tubing in the vicinity of the leak is under way
Further corrosion measurements will be made in this loop with the U7U ratio at about 10 Additions of N i F 2 traquo the salt will be made to raise the U ^ U 3 ratio to the desired level
683 Coolant Salt Thermal Convection Loops
Thermal convection loop NCL 31 is constructed of type 316 stainless steel and contains LiF-BeF2 (66-34 mole ) coolant salt The 16 removable corrosion specishymens are also nude of type 316 stainless steel The maximum temperature of the loop is 639degC and the minimum temperature is 482degC The initial objective of
I I L M Toth and L O Gilpatrick The Equilibrium of Dilute UP Solutions Contained in (imphite ORNL-TM-4056 (December 1972)
95
_o o
tvri O
o O
-o d
FtJ 644 Microfracture of Incoad 601 exposed lo MSBR fad sah al 704 C for 720 hr As polished
Y-1312W
BackscoMered Electrons ThMc X-Roys
Ffc 645 Electron beam scanning image of Incond 601 exposed lo MSBR luH tall for 720 br al 7 0 4 C
HImdash3000 COUNTS FUU SCALE Ctmdash3000 COUNTS FUU SCALE THmdash000 COUNTS FUU SCALE
~~1
Y - 1 3 1 2 1 9
I L i JLJJJ - mi
Ffe 646 Mfcfopnbe ctmtimomi K M K M M M corroded ana in IMCOMI 601 exposed io MSMt M salt for 720 hr at 704deg C
97
Fij 647 Microstnctare of lacoael 601 exposed to MSraquoR fad alt at S66degC for 720 kr As pofohed
cobalt-base alloys is being evaluated in the unstressed condition in the TV A Bull Run Steam Rant Two heats of standard Hastelloy N tubing (N1S09S and N1SI01) are being evaluated in the stressed condition from 280 X 10 to 770 X IO Jpsi
The method whereby the specimens are stressed is shown in Fig 649 The wall thickness of the gage secshytion of the specimens was varied from 0D10 in (77X) X 10 psi) to 0030 in (280 X 10 1 psi) to produce the desired stress range The raquo-in-OD capillary tube conshynects the annulus between the two tubes to the conshydenser When the inner tube ruptures steam passes through the capillary and a rise in temperature of a thermocouple attached to the capillary indicates rupshyture Time to rupture can be taken directly from the multipoint recorder and plotted vs sfess for design purshyposes Data of this type for periods as long as 11000 hr were reported previously17
A photograph of the specimen holder (Fig -gt0) shows the ten instrumented stressed specimens the four uninstrumented stressed specimens in the filter basket and the unstressed sheet specimens bolted to the speci-
12 B McNabb and H E McCoy MSR Program Semiarmu Progr Rep Feb 28 1975 ORNI 5047 pp 94-101
OJKM-0W4 TS-lt22laquolaquo
O 500 IO00 ISOO 2000 2500 3000 3500 SPCCIMEN EXPOSURE TIME (hr)
Ffc 648 wetgtt changes of HMCHOY N from loop FCL-2b exposed to MSBR fact salt at die Minted temperatare
this loop is to provide baseline corrosion data on a comshymercial iron-base alloy The loop has been in operation for 248 hr
69 CORROSION OF HASTELLOY N AND OTHER ALLOYS IN STEAM
B McNabb HE McCoy
The corrosion resistance of several heats of standard and modified Hastelloy N and other iron- nickel- and
98
OB -OK M - 3
STEM SUPPLY 99ooplaquomgtr
t laquo - IT raquolaquobulllaquo
C t f U M V f TUBE
TUBE BURST SPECIMEN (TYP 10) WATER OUT
RETURN TO CONDENSATE STORAGE
f 649 ScfccaMtk of dostfe-watcd tobe-barst eciam
men holder The filter basket bolts to the small flanges on each side of the sheet specimens (shown exposed) so that the specimens are covered and the flow of steam is uirected over the specimens rather than around them The steam enters the specimen chamber near the middle of the stressed specimens in front of the unstressed specimen holder and is directed lengthwise over the two stacks of 2-in-long X H-in-wide X 0035-in-thick sheet specimens The steam passing over the specimens flows through the Neva-Clog filter to prevent scale from entershying the flow restricter orifice or the remainder of the steam system The steam is condensed and relumed to the condensate storage vessel No specimen has lost any scale so far but some of the Croloy-type alloys are beginning to develop blisters a prelude to scaling The oxide on all HasteUoy N specimens is thin and adshyherent with no evidence of scaling Some of the unshystressed Hasteiloy N specimens have been exposed to steam for 19000 hr at 538degC and 3500 psig Several alloys were included in this study andas reported preshyviously 3 they displayed a wide range of oxidation rates Several obeyed the parabolic rate law Aw = Kt0gt where Aw is the weight change in mgcm 2 r is the time in hours and AT is a constant Figure 6SI is a
log-log plot of weigh change in mgcm as a function of time in hours Note the sudden increase hi the rate of weight change with each alloy gaining approximately 05 mgcm z over the last 4000 hr This probably indishycates deposition of some substance on the specimens at a rate that was equal for all specimens We noted preshyviously that fine particles of iron oxide that was enshytrained in the steam had deposited on the specimens but this deposition occurred at a much lower and conshystant rale
The increased rale of weight gain for bulllaquo specimens was discussed with Bull Run engineers The Butt Run facility has had several instances of condenser tube leaks in the last year of operation whereas in previous years few if any condenser leaks occurred The cooling water in the condensers is at higher pressure than the condensshying steam to prevent back pressure on the turbines and when a leak occurs untreated cooling water is introshyduced into the steam system hot wed Continuous monitoring of silicon in the four hot wells (condensed
13 H K McCoy and B McNabb Common of Seven fron-md SirkelBttr AUoyj in SMptnrihctl Steam tt IWmfF ORNL-TM-4552(AupB( 19741
99
yen ttSO fhnnnif of MM M H mwooaw dumber attar I9JBM hr of ixpamdashJI Fntaro to note ire the ftrcacd D M mcmlnMnmicd iptcimem m ihr fitter Iforeiivimdl the two grown laquo f umtreued ipecanens and the tea nwuaacMcd tfrcued iptnanm The Miem-rf ltrcanem haw an oniadc domclcr at I in and a length of 3 in
steam wdfc) indicates a condenser leak when the silicon lewd increases and the leaking condenser can be isoshylated and repaired The condensed steam (and any coolshying water mtrodticed by condenser leakage) poses through demineahzrrs and is ntonitored again with silishycon and other irapuifies being held below acceptable broils before the condensate is returned to the steam system Even though care is taken to prevent excessive amounts of imonritres in the steam system the farihiy is evidently opt rating with a different level of impurities than had been experienced before condenser problems developed Some evidence of indium shkate as a Mack-Mi gray deponihas been observed on some safety-valve seats and this is poanoty the material that has deposited on the specimens The oxide on most of the specimens is Mack or gray and no changes in i u appearance were noticed during routine examination and weighing of the
specimens When the specimen holder is removed for the next scheduled examination an effort w i l be made to determine the composition and nature of the deposit
by Bofl Run engineers in the near future to ehrninate the problem of condenser leaks
Some of the aloys represented in Fig 651 lost weight inriiany before gaming at an accefcaraied rate during the last 4000 hr These alloys were Hastetoy X ttsynes alloy 188 and rnconel 718 and they contain approximately 205 Cr Other juvestigstors have reshyported weight losses due to loss of chromium in steam at high temperatures I i is probable that these aHoys would have continued to lose weight if the steam conshyditions had not changed new specimens of some of the aloys WW be inserted in the lest facility when sieam conditions improve
MS
t I t OBSERVATIONS OF REACTIONS IN METAL-TELLURIUM-SALT SYSTEMS
J Brynestad
Several criteria must be met for a good screening test system for the teflurium corrosion of Hasteloy N
1 The teflurhun activity must be appropriate reproshyducible and known
2 The tefflurium must be ddivered uniformly over the sm|jie surfaces and at a rate sufficient to prevent excessive testing times
3 Preferably the system should operate under invarishyant conditions during the test run
4 The system must be relatively cheap simple and easy to operate
in the MSBR the production of tellurium per time unit wnl quickly reach a constant value and in due time a steady state will be reached where telurium is reshymoved from the melt at a rate that equals the rate at which tellurium is produced
i to reacting with me Material of which the circuit is constructed leBunum could be reshy
moved by several means which mdmfc the foetamug
1 The | ining system Since the MSBR is to be equipped with a pm ceiling system to remove Gemm product telufium might be effectively removed from the salt by appropriate measures
2 The gas phase If the gas phase is contacted with a getter such as dumnium wool the tchwrimn activity m the men ought be kept dose to that defined by thelaquo
^Cr TTe(k)^ TeltgH ACrlts)
Thu activity is sufficiently low that Hastdoy N would not be attacked
3 A getter immersed in the salt mdt Obvious disshyadvantages of this arrangement would be the probshylems of mass transport in temperature gradients and the lack of a candidate material
Until the steady-state condition in an MSBR is more dearly defined it is impossible to state the likely tellushyrium activity It is only known that in the MSRE stanshydard IfasteOoy N was embrittled (probably by tellushyrium) In the MSRE the steady-state tellurium activity - if ever reached - probably was defined by gas phase removal and was likely rather high
Until the steady-state situation in the MSBR is deshyfined it must be assumed that one must deal with the MSRE condition under which standard Hastdloy N is embrittled In order to define this condition we have tested several systems with defined tellurium activities with regard to their behavior toward HasteHoy N
1 equilibrium mixture of C^Tejfs) + CrjTe4(s) 2 equilibrium mixture of NijTej(0j 41 at 7 Te) +
NiTe 077J(7I ^ 437 at Te) 3 equilibrium mixture of CrjTe 4(s) + CrTc6(s) 4 equibbriun lixture of Ni 3Te(s) + Ni(s)
The systems are arranged in sequence of decreasing Te 2
activity as determined by isopiestic experiments Typical corrosion experiments were contacted at 700degC for 250 to 1000 hr The arrangements were by isothermal gas phase transport of Te in previously evacuated sealed-off quartz ampuls by embedding the specimens in the mixtures and in the Cr2Tej-CrTelaquo and CrjTe4-Cr4Te6 cases by transport in molten salt
The most pertinent results are as follows
I Hasldloy N samples exposed to NiTej(s) bull Ni(s) (system 4) did not show intergranular cracking This is promising because if one a n establish a steady-
M l
dak luaawiun m which the telahaa activity is kwcr HOT OOI aefaed by das system staadanJ Haacaoy N wtl wot be eaaaittled
2 Sysaeas I awl 2 have teMaaa activities thai are loo high Ibex sysseas corrode Hasseaoy N sevcaeh water af the experiaeatal w w y a w i aad
3 Systea 3 fCrjTelaquolts) + CrTeraquoltsti SIUHH proaase as a iraariaa-deaivery actboa a aohea sansacc it B saffvseatry corrosive to cane aterpawatar cactoag of thk-caoy N b a docs aot fora acactioa layers
It is of value to note dot the systea Cr7Te(s| bull Ctls) has a tehaiaa activity that B mar lower thaa the systea NiTe2(s) fifs) l as systea abo is proa-isag since lagh surface duoaaaa aiebt be used a a tdariaa getter a the fas phase Experiments are water way to measure the telariaa activities of the above systems
611 OKRATIONOF METAL TEJXURJUM-SALT SYSTEMS
J R keissr J Brynesud J R DiStefaao EJLawrcace
The discovery of Jtatk intergranular cracking of HasteBoy N parts of the Molten-Sail Reactor Experishyment which were exposed to furl salt led to a research effort which identified the fission product tellurium as the probable cause of the cracking Experiments showed that HasteBoy N specimens which had been dectro-plaied with tellurium or exposed to telariaa vapor exhibited shallow intergraniaar cracking like that of specimens exposed in the MSRE Subsequently a proshygram was initiated to find an alloying modification for HasteHoy N which would enhance its resistance to teiu-rium The resistance of these modified alloys to crackshying is measured by exposing specimens to leaiirium vapor deforming them and then evaluating their surshyfaces by metallograpruc and Auger methods However the chemical activity of tellurium in these experiments raquo significantly higher than it was in the MSRE In order raquoo simultaneously expose specimens to the combined corrosive action of molten fluoride salt and telurium at a more realistic chemical activity a method is being sought for adding tellurium to molten salt in a manner that would simulate the appearance of lefurium as a fission product Experiments have been started that wia permit evaluation of several methods to determine whether they will produce the desired conditions
61 II Teaaraan Expcnacatal Pal I
Tellurium experimental pot 1 was built to evaluate the use of lithium telluride as a means for adding lefu-
riaa to safe Has pot laquoRg 632)aVws t d a a a lobe
BaaaaWC PJKBTBBH t a W t m a f f e a l tan a a r a n f H M K I BBBEBY a a a V aj w^ laquo ^ n i w araquovraquo ^ ^ p a t s waaaaajaa ^^a avaa BPUiawavww a a wuvu a a a i aaawaa
through Tefloa seals aad are used Or delect aad aeaa JK
14 The Nrtimdash laquo fan far As nacnacw raquo raquo fnfmt4 bully vannr t JHB ncaacny i mc ootiiuuucvKai B a M i i o o bull a t m4t traquo aryci raquo4 ) b M r
102
I bull UF-lef -ThF 4 (72-16-12 mdk mi m tern- A rfastetoy N pat was filed with the salt LiF-ftcfV latoSOTC ThFlaquo (72-16-12 aaok ) mi the temperature conshy
trasted at 700C After a sample of the salt had been lixTe which w pscpMcd hy the tafcea CrTelaquo was added mi a M I Hasteaoy N sheet
(Sect 31) hat i i i j two pdhsts specimen was inserted hMo the salt After 170 hr the a total of 0170 g of l i jTe were added to tjrrrwnrn was reamed and after 250 hr a salt simple
I of saw taocaoJwwkji enmamiua of the salt wax taken The teaaperatare was thea lowered to 650degC of oar ftadynra Chtaaitijr Draw gave aad a day user a sab sample was again takca This of the preseace of irlmiiia (Sect S3) xoacace was thea repeated at 600C Next the salt
dace aancIiiTepdkts west added aad te-ptrataie was rawed to 7O0C Cr Te was added a sawffc of Ae salt was takes for choanal analysis aad aaother Hastetoy N spedaaea iasertcd Ihe sped-Thre- addaaoas of CrF 2 totaling IJ2 g were thea a n was reasoned aad sah samples were tafcea under the aanle roauaed hy the aaaaaoa of theee awe li jTe same tjaw4eaagteratare coaditioas as discussed abouc
A anal iddirtja i nailing of 02 g of 10 was The two Hasteloy N spediaeas we submitted for Anger examination No were detected bat twdeace of tdariaai in the grain
foaad (Sect 612) The results of thr of the salt snaade are shown in Table
614 Tcaaraaa ooaceatratioas at 700C were not as bjgb as was expected bat the tact that some tct-irium was ia solution is deaaoastiated by the teHariam found oa the tpniannt Addrtioaal CrjTe was added to the
two salt samples were take lYriincaary that the soJatioa any not lane been
i the first series of salt samples was ulten the solafcarry measurements two tensile
icre exposed to the sah-CrjTcj solution Both specaaeas oae of rcfabr Hastcloy N and oraquo of lift Mraquo-07 Ti uwdrfied Hasteloy N showrd a
after 500 t_r exposare at 700C After iheregabr Hastetoy
N jpuinun was obatmd to lane agaificaatty more aad cracks than dhJ the modified Hasteloy N sped-
i (Sect 614)
r6M
611J
The adfciua of a CrjTty or CrgtTlaquo4 at anj stall aaothtr awaVod for
toaHaamMSMfanadtiraaesceai of ehraawam idhaldt is bullanafaajsi aat acttwiy of
at the adt wM he otnunaat pro-
To at which canter of thaat chro-
bullw wWwWwaPpPIbull VraW) ^ppaaar bull ajwPTff
of the chromta Mftaridat as s faac-
Tlaquoaa rnmauddNoanan M )
Moaa^aVStwMw bullnoTci After
OTe After
Ctlt tUHiam
im Tlaquo 5 0 4 4
Tlaquolt5 Cr7S
Tlaquolt5 CrlaquoJ
656 Tlaquo 151 CrIOS
Te75 Crl20
tan Tlaquolt5 rr
Tlaquolt5 OBJ
103
The experimental assembly is being used to expose standard Ifasteiloy N specimens to salt containing Cr Tej to obtain data on the extent of attack at 700degC as a function of time
611J Telwnum Expctunxwtal INN 2
When a technique for introducing telurium into salt at an acceptable chemical activity has been developed a method will be needed for exposing a large number of specimens to salt-tellurium solutions A Urge experishymental pot has been constructed for this purpose The pot has a stirring mechanism facilities for introduction of electrochemical probes and sufficient accesvi to allow dmulianeous exposure of a large number of specishymens Operation of the system will begin when a satisshyfactory tellurium addition technique is available
612 GRAIN MUNDARY EMHtlTTLpoundMENT OF HASTELLOY N BY TELLURIUM
R E Clausing L Heatherly
Auger electron spectroscopy (AES) is a powerful technique for studying grain boundary embrittlement of Hasidloy N by tellurium The recent development of the technique to permit AES analysis win a small-diameter (--5-fi) electron beam to excite the Auger elecshytrons of a specimen surface has made truly microscopic analysis possible1 5 The development of techniques for scanning the beam and the development of electronic data processing equipment have continued to be a censhytral pari of our efforts As the techniques improve our ability to see the details of the telurium embrittlemenl process improves dramatically We can now not only provide a qualitative image of the elemental distribution on intergranular fracture surfaces at a magnification of several hundred limes but we can aho provide a semishyquantitative elemental analysis as the beam it scanned along a line across the sample However it is not presshyently practical to provide a quantitative analysis along a line across an rntergranubr fracture surface since Auger intensities at each point OR a rough surface vary accordshying to topography This effect can be corrected in prinshyciple by a normaliation technique but data for each point must be normuhad mdrvKJuaRy and the present equipment cannot handk the volume of data required The data presented below are typical of several samples of lefluriurn-envbrittled HnHcRoy N that were examined recently These samples are being studied in various
15 R I ltlMlaquonf ami I Ikjihrrly VWT ftn^wm Srmi mmu rmtr Rrp fth J bulllt ORNI -5ltM7 p MM
pans of our previowtty outlined efforts to understand the tellurium embrtttkment of nickel-based alloys The sample chosen for the present discussior demonstrates our state-of-the-art capabilities and limitations and at the same time provides some new insights into the nature of the tellurium embrittlement of Hasteloy N
A sample of Hasteuoy N that had been exposed to tellurium vapor at low partial pressure for SOO hr at 700degC was fractured in the AES system and the resultshying fracture surface was analyzed using Auger electron spectroscopy The fracture surface is shown in Fig 6 3 3 The scanning electron micrographs made by Crowe reveal that intergranular fracture occurred along the edges of the sample and that the central reejon faded in a ductile manner One fairly large area of ductile shear can be seen Three types of Auger data presentations are used below imaging line scans and selected area analyses The first is qualitative while the second and third are progressively more quantitative
Figure 634 is an image obtained using the scanning beam in the AES system and the absorbed sample curshyrent to produce the image contrast It is similar to the scanning electron micrograph (la) but because of the larger electron beam and the different method for proshyducing the image contrast the resolution in Fig 654a is poorer and some distortion is evident Nevertheless it is relatively easy to correlate the features shown in Fig 634a with those in Fig 633a Figure 6346 is an image of the same area shown in Fig 634a but with image contrast produced by the tellurium Auger signal A careshyful comparison of the areas of high tellurium concentrashytion with the areas of intergranular fracture shows that a good correlation exists between the two No telurium can be detected in the regions of ductile or shear fracshyture Figure 6 3 5 b a series of line scans showing the peak-to-peak intensity of the Auger rignah for nickel molybdenum chromium and tellurium as the electron beam was scanned along the path shown by the bright line Hi Fig 654a Some of the observations that can be made are (I) The intensities of the Auger signals are influenced considerably by topography that is some features such as the shear region between feature gt and the ieRuriumlaquombrittled region below it show lower Auger emission for al dements (this dependence on topography accounts for much of the jagged nature of the line scant 12) The lefurium concentration is quite high in the region of mtergranuiar fracture near each original surfaor ltJ| There is a definite tendency for the concentration of molybdenum to be higher in the regions of intergranular fracture (41 The nickd and chromium concentrations are in approjumatety the same ratio throughout the scan
104
ltaraquo 2nox ifrgt sonx laquorraquo nmraquolaquo wgt torn lto jonox Tt
105
Y-133510
Crack
Te Ertrittled
I i raquo i gt MICffOftS 375
j j TTT90raquoi i i S i i i r r i I005 INCHES 0015
F fcM MI l i w u i rtmw bull laquo raquo laquo gt mm to raquo AES Fht brnrfii wiiiul law dnraquoraquo the path irf ibr IMW laquo M 4laquol HJaMMrt ftftom in laquo fc-35 (M h M p e f otoMawajgiMM
NJ 4t M M n Aapjf bull bull bullgt pMaJwt nartmrt The onkriiiM fraai tuwJjiy ngtam m i to th
106
Traquo-laquo4T
Flj tSS Anger ajnJ Menrities for scans atony Ike path wdicXcd sn Fjsgt 6S4 The vertical axis is displaced and the vertical scales arbitrarily varied to permit a qualitative comparison of the variations of Ni Cr Te and Mo as a function of distance along the scan line The tones and features identified along the horizontal axri are also identilied in Fig 6_S4raquo and c The AES analysis of the regions bbeied area I area 2 and area 3 are given in Table 615
Another observation based on the detailed examinashytion of this and other samples is that the tellurium conshycentration hi the grain boundary is not a monotonically decreasing function as one proceeds inward from the original surface On nearly all of the embrittled samples examined thus far the tellurium concentration is uni-formnJry high throughout the embrittled area as for example is shown on the right in Fig 655 (The signal intensity on the left is strongly influenced by toposhygraphy- If this effect were removed by a normalization process Ms area would have a more nearly uniform composition similar to that on the right) The high relashytively uniform telurium concentration in the embrittled regions suggests that either a particular grain boundary phase of fixed composition may exist or that the tellushyrium atom fill all of the appropriate grain boundary sites in the embrittled region Sputtering this fracture surface (and those of similar samples) to a depth of a few atomic layers (3 to 10) reduced the tellurium conshycentration to below I at showing that the tellurium is concentrated very sharply in the grain boundary it is
therefore unlikely that the tellurium present in the grain boundary exhibits the properties of a bulk tdluride The molybdenum concentration remained high during sputtering operation indicating that the concentration of molybdenum is high in the bulk phase perhaps in a phase that has precipitated in the grain boundary
Table 615 shows quantitative selected-area analyses made in the three regions of the sample indicated in Fig 654c The compositions have been normalized to equal 100 at in each row The three rows for each area are obtained from one Auger spectra but some elements were ignored in the first two rows to make changes in the relative amounts of the other elements more obvious These results confirm the above conclusions and show ( I ) that tellurium is present in relatively large amounts in the embrittled regions and (2) that area 3 which is near the extreme of the depth to which the tellurium penetrated contains about as much tellurium as area 2 which is located near the center of the upper embrittled region Regions 2 and 3 are both enriched in molybdenum and carbon M indicated in the line scans
107
r4IS Cuaiummnofi ofaHamdmyNa
tor Suffer at 7 laquo r c
Rezwn Composition in laquo5r
Ni Mo Ct O
Composition in the lower repon area 3 imiertranitU fracture)
Cohipositioi in ocntral region area I (dacine lnlaquoiuregt
Composition in ike upper repon arcs 2 imlergwiutar fracture
70 1 11 M 1 10 9 40 II 6 6 75 16 9 75 16 9 61 13 8 64 25 12 58 23 II 8 42 17 8 6
33
13
I I
Areas identified in FBJ 6-54r The composition in each row is normalized lo cquai 100 at ri The three rows
lor each repon are from the same data but are normabted so as to make changes bulln retain amount of the dements more obvimn For convenience and consistency in repot inc data we astame the AF5 spectra tfaol Pabnbetf et aL Htndhook of Anger Electron Spectroscopy Physical Electronics Industries Inc Fdiru Minn I972l are accurate and directly applicable to our data Elemental sensitmwes are taken directly from the spectra presented m the handbook with no attempt lo correct for chenaca effects line shape matrix effects escape depth or distribution of dements as a fraction of depth in the sample The analyzer used is Varian model 981-2707 operated with an SOOOeV electron beam energy
The above results suggest the need for a detailed examination of the causes and effects of the high moshylybdenum and carbon contents in the grain boundary region and abo an examination of the irnphcations that the presence of a two-dimensional tellurium-rich grain boundary phase may have on the time dependence of tellurium penetration into the alloy
613 X-RAY IDENTIFICATION OF REACTION PRODUCTS OF HASTELLOY N EXPOSED TO TEIXimiUMCONTAlMNC ENVIRONMENTS
D N Braski
Hasteiloy N and several modifications of the alloy have been exposed to tellurium to determine their rda-ive susceptibilities to intergranular cracking Different nethods for exposing samples to tellurium have also
been studied in an attempt to develop a suitable screenshying test for the alloy aVvctopmenl program Some specishymens were exposed directly to tellurium vapor at 700degC while others were subjected io attack by nickel or chromium teBurides at 700 and 750V respectively This section presents the results of x-ray diffraction analyses of reaction products producerl during the tests Knowledge of the reaction products akts in evaluating a
given method of tellurium exposure and may provide information relating to the mechanisms of intergranular cracking
A number of Hastefloy N tensile specimens and flat x-ray samples were exposed to tellurium vapor at 700 SC for 1000 hr in an experiment conducted by Keimers and Valentine The specimens were positioned in the top portion of a long quartz tube having a smal amount of teiurium at the bottom The tube was evacuated backfilled with argon and placed hi a gradient furnace with the specimens at 700C and the trtiiium source at 440C With this arrangement teuurium vapor diffused upward through the tube at a rate dependent on the temperature difference between the specimens and the tellurium CM)Xgt5 mg TehrV At the end of 1000 hr exposure the specimens were covered with a very fine hairlike deposit similar to that observed previously in creep tests at 6 5 0 C 7 The results of x-ray diffraction analyses on these deposits are given in Table 616 The first alloy listed is standard Hasteftoy N while the other three have titanium and niobium additions The main
16 A D Keimers ami D Y Vatentme MSK Ammjm Semi IMII rrogr Rep Feb 2S 1975 ORNL-5047 pp 40 41
17 R F GeMhach and H HensonMSK hvpmm jViinwm frogr Hep An J I 1972 ORNL-4832 pp 79 86
108
TaUcfclt X-faydifTrartiMi malts fori IO0O brat 700 C
Hat number t lt aftoyinx
additions to nominal HasteBoy N composition
Method of tellurium expovire
Surface reaction products
405065 None kelmervVaknime experiment^
NiTe CtJe
472-503 M r Ti kctroerv Valentine experiment4
NiTe
470-835 0711 Ti 261 Nb Kebners-Vakn line experiment
NiTe CrTe
IK) 841 Nb Kdmers-Valeniine experiment
Ni rTe
474-533 201 Ti Brynestid low Te ac irrily exposure NiTets) + Nitsgt
NiTe unidentified substance
405065 None Bryncstad LiO + CrTe
N i T laquo + N i T e
V D Kdmersaad D Y ValentineMSR Fran Srmunnu Prop Rep Feb 28 1975 ORNL-5047 pp 40-41 J BrynestadVSR Prognm Senaamu Prvgr ltep Feb 28 1975 ORNL-5047 p 102
reaction product was NijTe 2 which was detected on the surfaces of all four alloys (NijTe was found on earlier samples exposed for shorter times in the same apparatus) X-ray lines which could be indexed as CfTe4 were also found on standard Hastelloy N and on the alloy modifkJ with 071 Ti plus 263 Nb The Cr jTe 4 interplanar spacing and relative intensities were calculated by H L Yakel Metals and Ceramics Divishysion from the crystallographic data in ref 18 The presshyence of CrTe4 in the reaction layer is reasonable beshycause both chromium and tellurium were detected pre viously on Hasteiloy N exposed to nickel telluriddes by electron mkroprobe analysis1 In addition chromium tdlurides were previously identified by x-ray diffraction on Hastelloy N exposed to tellurium vapor17
Brynestad20 exposed 2 Ti modified Hastelloy N specimens to a low tellurium activity (Ni3Te + Ni mixshytwe) at elevated temperatures The specimens were first placed in a quartz tube and the Ni JTe 2 + Ni powder mixture packed around the specimens The tube was then sealed off under vacuum and placed in a furnace at 700degC for 1000 hr The reaction products obtained in this test also contained NijTe2 but the remaining four lines could not be satisfactorily indexed to any of the
18 A V Berfaul G Rnull R Aleonard R Pauthcnct M CVvTctou and R Jansen Structure Magnet iqucs de CtX 4
raquoX = S SeTeh Phvs Radium hi)582 95 (1964) 19 D N Braski O B Cavin and R S Ctmae MSR Prltt-
gnm Semtannu Fmgr Rep Frh 28 1975 ORNL-5047 pp 10$ 09
20 J BryncMad MSR Program lemktnnu Pmtr Rep Frh 28 i975 ORNL-5M7 p 102
Ni Cr or Mo tellurides The unusually broadened x-ray diffraction peaks suggest that a complicated teluride such as Ni-Cr-Te may have been formed In another tellurium experiment Brynestad exposed a standard Hastelloy N tensile specimen to a melt of LiCI containshying Cr 2Te 3 (solid) at 50degC Some Cr 2Te dissolved in the LiCI melt and reacted with the HasteUoy N After 146 hr the tensile specimen was removed and the flat surface on one end was analyzed by x-ray diffraction The results (Table 616) showed that Ni3Te2 and NiTe0 were produced
In summary these tests have shown that the primary reaction product between Hastelloy N and tellurium near 700degC is NijTe X-ray lines corrsponding to Cr iTe 4 were also present in patterns from the surfaces of several Hastelloy N alloys exposed to tellurium vapor at 700degC Exposure of Hasteiloy N to tellurium at low activities (NijTe2 + Ni mixture) may have produced some complicated Ni-Cr-Te compounds in addition to NiTe2 as evidenced by the unusually broadened x-ray lines
614 METALLOGRAFHIC EXAMINATION OF SAMPLES EXPOSED TO
TELLURIUM-CONTAININC ENVIRONMENTS
H E McCoy B McNabb J C Feltner
Several samples of modified Hastelloy N were exposed to tellurium-containing environments They were deshyformed to failure at 2SdegC a procedure v-hich forms surface cracks if the grain boundaries are brittle a
109
metallographk section of each was prepared to detershymine the extent of cracking- These tests hawe two objecshytives The tint is to dewlop a method for exposing samples to leBurium to produce a reaction nte comshyparable to those anticipated for an MSBR This rate is thought to be a flux of teOurium of about I0 1 atoms cm 1 sec- The second is to compare the cracking tendencies of arious alloys of modified HasteBoy N
A new technique developed for measuring the extent of cracking is more nearly quantitative than that used previously In the new technique a mounted and polished longitudinal section of a deformed specimen is viewed on a standard metallurgical microscope The eyepiece has a fiar which can be rawed to various locatiom in the field being viewed The filar is attached to a transshyducer which produces an output voltage that is a funcshy
tion of the location The output signal is interlaced with a scull computer which WH on command compute crack lengths and several statistical parameters The information is displayed on a teletypewriter The cracked edge of the mounted specimen is scribed every 01 in_ and the operator measures a l cracks in successhysive 01-in intervals untl at least 30 cracks have been measured The computer then calcinates and displays the average crack length the maximum crack length the standard deviation and the 95- confidence interval A typical scan requires about 10 mm and is considershyably faster than other methods used thus far
The experimental conditions associated with the ten experiments to be discussed in this report are summashyrized in Table 617 The chemical compositions of the alloys studied are given in Table 618 In all cases the
T J U T pound I 7 Cenoal4cxiiftmm ofTe-HaMenoy N a y w t t
Experiment IXcsipna (km Experimenters Exposure
conditions Alloys
bullMinded Genera
75-1 Brynesud UCl + Cr Te for I 4 6 n r a l - 7 5 0 C
405065
75-2 Krimcrs Tc vapor for Valentine |l)00 bral 700 C 405065
470-835 472-503
ISO
75-3 Bryneslad 250 hr at65ITC 405065 pa-kedin( r Te 474-534
474-535
75-4 Bryncstad 200hraf 700 C packed in Cf Te
405065
75-5 Biyncstad 504 hr at 700 C 405065 Keiser in s i t bull Cr Te 470-R35
75-6 Brvnestad 000hra l700C with vapor above Cr Te 4
405065
75-7 Brvrrslad 1000 hral 700 C with vapor above Cr Te
405065
75-8 Brynestad 1000 hr at 7 0 f l T laquo i l h vapor above J gt nH-kel tellurides
405065
75-9 McNafcb 250 hi al 7laquofC in 405065471-114474-534 McCoy vapor above Tc al 474-5356006006263
300 C I H 237295 297 298 303305306345346 34734821543469-344 469-648469-714470-786 470-835
75-10 McNabb 250hra l700 C in 40506521543 345348 McCoy vapot above Te al
300C 4 1 1 4 1 laquo21424425
Heavy reaction lay en
Whisker growth evidence of inhomopenoas reaction withTe
Heavy reaction layers
Heavy reaction layer
Reaction layers
No visible reaction ayers
Shallow reaction layers
No visible reaction layers
No visible reaction layers
No risible reaction layers
See Table 618 for chemical compositions A D Kilmers and I) Y Valenlnc M$R Program Srmimmi FriffT Kip Feb -X V75 ORNI-5047 pp 40 41
110
t6lt
Heaimoabei Mo Cr Fe Ma C Si Ti Mb At Of her
62 134 752 a 020 0042 001 a 19 63 145 7 J 3 a 020 0135 001 a 25 l raquo 12 70 0040 022 0046 OJOI lt002 184 ISI IS 684 0054 0-23 045 001 050 185 003 W 237 20 67 43 049 0032 m 004 103 lt0-05 295 14 806 402 0 28 0057 lt002 lt002 085 0 0 5 296 15 809 396 028 0059 lt002 lt002 12 02 W 297 29S 303
2 1 20 20
70 70 70
40 40 40
02 02 02
0 0 6 006 006
002 0J02 0J02
024 lt00I
049
057 2J0 0J4
305 12 825 416 022 0072 009 088 I J 306 06 804 311 018 0065 027 001 OSS 345 IJO 71 38 026 005 022 002 045 346 110 67 37 018 005 048 002 049 347 20 7 43 025 005 047 lt002 088 34S 411 4 l i 42 424
20 20 20
120 120
72 70 70 70 70
007 a a a a
019 02 02 02 02
005 005 005 005 005
047 e a a a
lt002 a 1 0 219 18
042 115 113 104 134
007 010
42J 120 70 a 02 005 a 19 048 008 405065 160 71 40 055 006 057 lt00I a lt003 472-503 129 679 O089 lt00I 0066 0089 216 005 009 471-114 125 74 0062 002 0058 0026 175 a 007 474-534 1166 712 006 lt00I 008 003 20rgt a 053 014
0013 La 474-535 1179 730 005 lt00I 008 003 213 a 055 010 W
0010 La 003 Cr
600600 160 80 019 027 ltlnconcl600gt 469-64 128 69 030 034 0043 a 092 195 a 469-714 130 85 010 035 0013 a 08)) 160 a 470-835 125 79 068 060 0052 a 071 260 a 00311 Hf 40-76 122 76 041 043 0044 a 082 042 a 0024 Zr 469-344 130 74 40 056 011 a 077 17 a 0019 Zr bull21543 124 73 004 008 0050 0019 a 0 7 002
Not analyzed bur no intentional addition made of this dement
Not analyzed but nominal concentration indicated
sample was a small tensile specimen 56 in in diameter X 1 in long having a reduced section in in diameter X I in long All specimens were annealed I hr at I I77degC in argon prior to exposure to tefliirium The results of crack measurements and data resulting from the tensile tests at 25degC that were used to open the embrittled grain boundaries are shown in Table 619
Experiment 7S-I was run by Brynestad and involved a sample of standard Hastelloy N that was immersed in LiCl saturated with C r T e for 146 hr at 750degC The specimen formed a heavy reaction layer (Table 6 7 ) but lost weight (Table 619) Figure 656 shows that the reaction was rather extensive with some obvioia grain
boundary penetration which resulted in extensive crack formation in the deformed section The extent of reacshytion in this experiment was higher than anticipated for an MSBR and therefore it is not believed that the experimental conditions employed constitute a good screening method
Experiment 75-2 was run by Kelmers and Valentine and the detailed results were described previously2 All samples lost weight in this experiment (Table 619) Although the samples had more reaction product en
21 A D Kelmer ind D Y ValentineWW Program Smi-anmi Progr Rep hth 28 1975 ORNL-5047 pp40 41
Tabic 619 Inlf(granular vracfc formation anrt loniU propcrD of raquomnllaquoraquo oPlaquoraquovd In ulltMlum and ilralnad lo faHurv al 25 V
ffimmti H M I MMttof
CilaquockiMui k |0gt
C m k t f w C i K k t c m
D t p In ) SlWMbi 4fvulMgtn
1raquogt
CMflOIIWt W I U M I
I M I
W f laquo k l bull lung lmlaquol
VMM t u t u
ltbullbull rail
U I W M I f M M HltMH
t l O 1 ptl)
f l M I I M f H l t U
lt I 0 p i l l
U m f w m f lMUt lWH 4 I 0 ^ I raquo
P l M I W f HIM
K n l i w i i M M M M
11 MMraquofclaquo
H M I MMttof CilaquockiMui k |0gt
C m k t f w C i K k t c m A M I i f M W I R H U H
SlWMbi 4fvulMgtn
1raquogt
CMflOIIWt W I U M I
I M I
W f laquo k l bull lung lmlaquol
VMM t u t u
ltbullbull rail
U I W M I f M M HltMH
t l O 1 ptl)
f l M I I M f H l t U
lt I 0 p i l l
U m f w m f lMUt lWH 4 I 0 ^ I raquo
P l M I W f HIM
K n l i w i i M M M M
11
5 1 40505 ) | lgt 111 101 lt 1 7 1 4 ) 1 I T 4 1 1 1 4 ) M i l gt I 4 HI raquoJ-1 4 0 5 0 5 5 ) 0 1 1 4 t gt 7 5 7 1 1 1 4 5 1 0 SI 7 1 ) 4 7 I I 71 4 0 4 4 1 1 43 1
470-1)5 17 A t 1 7 7 0 I S 4 4 1 1 1 7 7 1410 l ) t laquo 4 1 5 44 0 ) S ) 4 7 ) 5 0 ) 100 I I I gt)) raquo7 0 1 4 I I sraquolaquo 1 5 ) 1 1 1 ) 0 ) l lt 4 0 4 410
iao t ) 15 1 4 ) 0 1 D l A l 47 5 4 5 1 1 4 ) U S I M l ) t 1ST 7 5 1 40515 140 laquo5 17 1 4 1 1 0 17 117 4 7 uto 1 0 0 4 0 1 414 4 1 4
474lt5)4 110 17 145 1 7 4 5 1 4 145 S t 114 0 1 0 0 411 441 S I T 4 7 4 5 ) 5 1 ) 0 bull I 1 0 ) M 4 5 4 1 1)1 4 S 4 not laquo 7 4 7 4 lot S 4 )
7S-laquo 40505 4 1 0 5 7 0 11114 l raquo ) S l 1 1 1 1 1 1 ) 5 11 ) 15 1 bull raquo I 7 7 1 1 ) l 44 1 44 0 10) 7 I N M ) H I 1 1 1 gt I 0 ) ) i ) 1 4 4 1 4 4 1 0 7 5 5 405115 170 14 4 1 5 raquo 0 I S S 1 bull 0 1 5 0 111 1 1 1 7 ) gtS ) 7 1 1 1 1
4 7 0 laquo J J 10 71 ))) 14 7 1 0 1 I t S I 5 1 1 I M 1 I M 7 17 0 ) 7 1 1 4 7 - 40505 115 15 I ) 1 1 4 1 ) 1 4 4 0 bull 001 S i t 1 1 1 ) 1 1 7 1 4 0 4 4 1 0 ))raquo 7 J 7 40505 510 )ogt 4011 1 0 1 4 1SS k i t 1 1 4 ins ) I 7 ) 4 ))gt 7 ) 1 40505 ) 0 141 5 5 bull lll 1 1 7 ) )raquo) Sl l 1 1 ) 1 1 1 7 4 4 0 0 414 5 1 7Jraquo 40505 H O 141 4 1 7 5 ) 151 I I I 7 5 1 1 1 7 ) 1110 M S 41 1 gtraquo4
4 7 1 0 1 4 l i 7 ) ) 7 4 )laquo I D 4 4 bull 1 4 4 7 1 1 ) 4 105 0 laquo raquo l 5 4 1 4 4 4 7 4 5 ) 4 ) 0 14 1 1 5 4 5 5 107 ) 1 7 I t l i t 1114 4 gt gt 45 S 411 15 140 I S 10 1 J M raquo l J7 0 5 1 5 1114 I D ) 4 t ) 4 1 ) 4 7 t HI 15 10 1 7 1 U I laquo I I bull ) 0 )raquo 1 0 1 7 4 U l gt 7 I S T )
M S 100 )raquo )raquo 4 l 1 1 1 1 4 bull 0 7 1 1 7 I I 1077 M l 41 I 4 raquo ) H t i l l ) 1 0 7 441 100 ) S bull 0 4 551 I l l 1117 41 1 44 7 4 7 1 M l 4 l I S ) l i 0 ) M l 1 1 ) 4 1075 4 1 5 4 5 511) J41 170 0 raquo I I I ) 7 ) l i i bull 1 S l l 1)1 1 l l t l 4CI 4 ) 1 4 ) 50 450 177 11 o 1 7 7 ) i i bull 0 1 too 1)00 1 1 1 17 4 4UI 4 ) 4 50) 450 l lt 1 4 1 1 raquo l i bull 1 1 I t 1 111) 1100 471 445 4 0 raquo 7 J i l l 111 1 1 0 4 1 0 1 1 u bull 1 1 t l 1 l i t ) 1 1 7 1 ) S gt ) T 4 4 1 5 15 15 10 10 1 1 7 ) i s 1 5 5 ) 5 1 1 ) 1 I M S 4 gt ) 4 4 4 4 4 1 )7 IS )) 14 1 ) I S I S i 0 5 1 4 l i l t I M S 4 ) 5 4 4 ) 4 4 505 H O 141 I t ) 1 7 1) 1 4 bullUS 5 ) 1 D t S 1 1 7 ) 4 4 1 4 1 4 7 7 M l 1)0 D O 1 7 ) 107 bull 4 1 1 bull 0 4 7 1 ) l l ) t 1104 4 1 7 4 raquo 4 7 11 110 17 1 7 1 1 1 7 ) 7 7 4 M I 1171 m i 4 1 4 4 S I M S ] 10 11 1 gt 1 4 0 4 4 5 IS 1 5 4 7 117) 110 1 4laquoT SOT 4 1 1
) 440 17) 117 1 7 S ) 1 I S l l l ) ) 4 111 7 gt J ) ) l o 41S 4 4 4 1 ) ) 0 1 ) 0 I I I 4 ) ) 7 4 1 bull 0 1 I I 1)1T 117) 4 ) 7 4 1 445 4 7 | 4 1 ) )) 114 5 0 4 1 1 4 5 bull 0 0 1 4 1 1117 l i t ) 8 ) 7 Hi 4 ) 4 4 7 0 O J ) )bullbull 1 1 4 7 SO 1 0 0 ) 5 5 IJ75 1)04 414 477 4 5 4 7 0 7 t )) 1 ) 1 ) 1 5 7 1 14 S 7 ) 0 ) 4S l i t 7 1 0 7 ) 5 0 4 S I 7 40 1 4 5 4 4 )raquo 141 l 171 V I 1 ) bull 0 07 5 1 7 1 ) 1 1 1 1 0 ) I 0 ) raquo 7 414 4 1 1 5 4 ) bull5 )) I I 1 4 4 4 1 17 11 45 4 not M I MT 5 7 )))
75 10 40505 M O I ) ) 177 4 1 ) 7 1 1 bull 0 0 4 5 ) 1 1 ) 1 4 1 1 ) 0 4 0 4 gt I 4 4 0 415 ) 0 0 I I I 17 1 54 1 I I 1 4 1 bullOS S l l l i t a 1 1 7 4 7 411 411 415 140 5 1 1 7 5 1 0 1 ) 4 ) laquo 0 0 l t i l l i t ) I I I ) 4 1 ) 410 4 7 411 M O 1)5 M4 raquo0 l 1 0 1 1 4 0 0 ) sso 1 1 7 111) 4 ) 7 4 5 4 4 1 4 414 4 ) 0 1 1 7 501 14 1 0 0 ) bull 7 4 l ) raquo ) 1 ) 1 7 44 1 411 gtbull) 11 101 1 1 17 1 0 54 0 74 bull0 1 1 ) 4 1111 1 1 ) 0 4 7 1 SI 1 1 1 7 15 M 10 I I I 1 5 1 ) l bull 0 1 5 ) 4 m i 1117 4 1 4 4 4 4 47 ) 541 M 1 ) 1 1 M l 71 15 bull 5 4 1 i n 107 1 44 1 4 7 4 54T M 5 15 5 raquoraquo 141 gt) i n bull 0 0 1 5 1 1 1 4 1074 4 4 ) 4T4 4S4 415 M 11 105 117 5) I S bullooi 5 ) 0 i n I IS S H 4 4 44X1 411 1 ) 141 ) 5 laquo 1 5 1 bull 14 4 1 1 1 1 ) 4 bull T I S I M l 5 ) 4
4 1 1 5 4 ) 17 7 10 1 ) 7 I I gtraquo bull 1 4 7 ) I D 1014 S I ) 1ST 5 ) 7
4laquou i MM tun bull 15V al bull tiiaM M M ul 0044 Mgt 1uUl laquomlil raquof yfmmtri 1 1 l o t 1 )
112
raquo gt laquo laquo bull
(b)
pornnaof
0-010 in 0 25
U t a M H I i th) tdft oi ureaed poriioa of 1
llaquowraquoCr Tca i7Mrci IflOX
HkrltlaquoiE ytoT
one end than the other the extent of lt icjaunably uniform Typical plsotonucrognphs of the (oar materiab are shown in Fig- 637 Aloys 40506S (standard) and 472-503 (216 Ti) formed extensive cracks but aloys 470435 (071 Ti 260 Nb) and 190 ( I J49 Nb) were considerably more resistant to cracking
in experiment 75-3 three samples were packed in CrTe grannies for 250 hr at 650degC The samples formed heavy nonadherent reaction products and lost weight (Table 619) All three materials formed extenshysive cracks (Table 619 Pig 638) with the depth of cracking being slightly less in the two modified alloys (474-534 and 474-535) than in standard Hnstdfoy N (heat 5065) However the extent of reaction is too high under these conditions for the results to be meaningful
bi experiment 75-4 duplicate samples of standard HastePoy N (405065) were packed in granules of CrTe4 and heated 200 hr at 700degC The samples formed nonadherent reaction firm and lost weight tarshying the test (Table 619) The reaction layer and the
the reaction rate was un-of the exposure cnadnioni as a
bull Fig 639 reasonably high for a
k experiment 75-5 Iryneslad and Keaer two specimens to MSW fad carrier salt (c uranium) that was saturated with CrjTcj The exshyposure was for 504 hr at 700C These samples formed reaction layers but lost weight (Table 619) As shown in Fnj 660 both uatcinls formed reaction layers but in heat 470-835 (071 Ti 260 Nb) there to be less penetration of the rcactants aVng the | boundaries The standard Hastdoy N had regions where layers of grams dropped not during the exposure The number and depth of cracks in the sliessed portion of the samples were less for heal 470435 than for stanshydard Hastcloy N but both materials formed extensive intergranutar cracks
Since the samples packed in the various telurides reacted extensively several experiments were run Hi which the samples and the teluride were separated in
113
(a)
(b)
(c)
- r - raquo
(d)
0 25 MI FfcS7 SywiwuM fcmdasht tfmmmm IS-l wfcMl wmdash laquo y mdash lt iraquoraquofciraquo raquo w laquo r f p w raquo o r irtNilmi far I W H m 7 W C n i
NralltOAraquo5tfrlfcril4-Slttilt I TiM Ilwtf 47MJ5 llraquo7l-lt Ti lA SbKultkat MRi lA f r Hbt AlaquopoMwl lOOx
114
(c )
(laquo )
(f) raquo bull O O W f
0 2 S laquo raquo
fplusmn S Ipniawn tnm rxpummM 75-3 Packed m CrTe granules for 250 hr al 650 C and deformed lo fracture ai 25 f flaquoraquo Heal 405065 Msireaed thy hear 405065 Urevwd tei heat 474-534 (2091 Ti 00131 Lagt imlaquorclaquoed (ltraquo heal 474-534 tlrcuedfrgt hear 474-535 (2131 TiOOH La 0031 Claquolunlaquoreslaquodlt1 heal 474-SJS laquorevd Atpnnshed lOOx
115
3ampF
bull 025am bull
the reaction capsule In experiment 75-6 standard Hasteuoy N was reacted with the vapor above CrTe 4 at 7000 for 1000 hr The spedmen pined a amount of weight (Table 619) did not form a reaction layer (Fig 6J6I ) but did form extensile inter-granular cracks (Fig 6 J 6 I Table 619) Experiment 75-7 was run in the same way but Cr 2Te was used The sample tost weight formed a surface reaction prodshyuct and formed mtergranutar cracks when strained (Table 619 Hg 662) In experiment 75-8 the source of tellurium was two nickel leRuriJes fc and 7 i The specimen lost weight did not forn a TJIMC surface reaction producl and did form rnieigranubr cracks (Table 619 Fig 6J63)L From these experiments it was concluded that the tellurium activity produced by Ct Te 4 was likely that best suited for screening studies
ExpeiHMnt 75-9 included 25 aloys which were exposed to tellurium vapor at 7000 for 250 hr The weight changes covered a range of +84 to 74 mg with no obvious correlation between weight change and crack depth or number (Table 619) These specimens were sealed in four different capsules for exposure to tellurium and there were differences in the extent of discoloration of the samples These differences are likely associated with slight differences in the extent of reaction due to variation of the temperature of the tellurium metal in the various capsules Thus it is quesshytionable raquo to how far one should carry the analysis of the data from this experiment
Owe further problem coacernmg data analysis which applies equaly w d to afl data sets is the baas that should be used for comparison The number of cracks ami their average depth are two very important paramshyeters However it is possible that a Tprrimrn cm have a large number of shaaow cracks ( e ^ beat 63 Table 619) or a few rather deep cracks (eg heat 62 Table 619) The formation of intergranuiar craci of any depth is important because this may indicate a tenshydency for embrittlement The depth of the cracks ts important because this is a measure of the rale of peneshytration of tefurium along the grain boundaries Howshyever for a relatively short test time (test 75-9 (2S0 hr)) the formation of numerous shalow cracks may be indicative of a near-surface reaction which wil not lead to rapid penetration with time Obviously longer-term tests are needed to determine the rate of penetration of tellurium into the metal
On the basis of number of cracks formed the alloys in experiment 75-9 which formed lew than 40 cracks per centimeter were 345470-835421543 237469-714 470-786 62 295 and 348 The alloys forming cracks with an average depth of lt 127 u were 63 469-714 295 348 469-344 421543 and 470-835 Several of the alloys appear good on the basis of both criteria These alloys all cont in niobium and several contain niobium and titanium Another parameter used for comparison was the product of the number of cracks and the average crack depth The alloys from expert-
l i t
( bull )
laquo
ltlaquov
(c)
lt)
I 0 2 9 raquo raquo gt Figt iuM Senates from uteiiaini 75-5 Sanpln exposed to feci all sraraKd laquo-iih Cr Tc for 504 hr ai 700C and strained
lo fraclarc al 25T ltraquo Standard HasteHor N bullntlrencd shoaMer (Agt standard HasteHoy N stressed p(c length sfoning region where grains were urn dnrine tall cipotnre (lt-gt heal 4704135 10717 Ti 260 Nb) oatlrroed thoakitr ltltgt heal 47f 4J5 stressed portion Aspotahcd I00X
117
(a)
(b)
l f l laquo Q l n - | I 0 2 9 M I
Flaquofcl TtiMwi lUmBij X ( h w O W I I w lono br mi earned to fjUarc ut F4pr of MM icwd pvnna iraquo lt
1154k ampMOftrtrfKMe4 lo the of tiinaei porno As pufcihfi
CrTlaquo j i7laquorCfof IflOx
ment 75-9 are ranked on this basis (Table 6J0gt Stan-dard Hasidoy N raquo significantly different from al other heats on this basis There are latfe variations among the other heats but it is difficult to pick out general trends on the basis of niobium and titanium concent rations
Several typical photomicrographs of samples from experiment 75-9 are shown in Fig 664 No reaction films were visible on any of these specimens The picshytures show dearly the wide range of cracking experishyenced by the various heats
The mechanical property data show small but signifishycant variations in the yield and ultimate tensile stresses of the various heals (Table 619) The higher stresses are grnerolly associated with the alloys containing the higher amounts of niobium and titanium However the
high fracture strain and reduction in area for a l h-ais indicate that only very small (if any) amounts of gamma prime formed during the 250 hr at 700degC
In experiment 75-10 steps were taken to ensure that the specimens were at a uniform 700degC and that the tdurium was at 300degC The weight changes were very erratic and show no correlation with the number of cracks or the depth of crack formation (Table 619) A sample of heat 425 was included in each of the two capsules used in tins experiment to obtain some idea of reproducibility The reprodudbflity was reasonably good Samples o alloys 405065 298 295 348 and 345 were included in experiments 7 5 4 and 75-10 Heats 405065 298 and 345 in experiment 75-9 cracked more severely than in experiment 75-10 Alloy
l i t
V - t
(b)
I AW hr art in
021 uigtiiiwil75-7 iioafAtlaquo4acor A
Cr f e j i ltKraquo lt t t HMta
laquo bull - - Craquofc
ltW SS^j-^n-raquobull
WMMMCS at ItXfC foe IWO hr aa laquo u m lt lo f IflOx
0 2 9 laquoMi itmtm 7W San phi r^puraquorf to Ike
to) Mat of mmiiwmtd porta raquogt claquogt laquo tf bull gt mcfcd
puftimi A ^riuhfd
IN
ITS
note bull bull laquo tat tract tdncti0c4 I cy
roat i
H m i oaccatraaoa t 0
( - -
I cy
roat i
H m Ti Nb (Mm
5laquon 4ltI5laquoraquo5 371 3lraquo 0 3 5 027 Si 3195 474-534 2 4 9 01013 U 27 JO 471-114 175 247 303 049 OM 2400 3ttS OM 13 2249 29S 20 217 3 2-5 2 1 29 024 0 3 7 1993 347 raquoM 0 4 7 Si 1924 4S14M 092 195 I9 IO 474-5J5 213 0 4 4 L raquo raquo pound r IBSI M U M P27 15 C i 1453 I I I 050 l-SS 1304 344 04laquo 049 1292 49-344 077 17 9 9 345 045 ft22Si 4 M 237 1J03 409 49-714 0S0 tJampO 352 2 1 9 raquolaquo 4 7 M 3 5 071 IM 290 421543 07 179 4707S 082 0 4 2 101 295 0 M 3raquo 34S 062 047 Si
Set TjNe 1H lw drbiM cheiwcJ jiulvcs
348 was less severely cracked in experiment 75-10 and Nat 295 reacted similariy in both tests Such differshyences emphasize the importance of duplicating test results before making important conclusions
The alloys in experiment 75-10 that formed lt32 crackscm were 413 34 295 4 1 1 421543 and 345 Those with average crack depths s 109 p were 421543 295413 345 and 298 Again this ranking is of quesshytionable value because alloy 298 had the shallowest cracks of the 12 specimens but formed a large number of cracks In an effort to combine the factors of number and depth of cracks the two factors were multiplied and the alloys ranked as shown in Table 621 There is a very large step between alloys 425 and 298 and the better alloys appear to be ones containing from 045 to 20 Nb with titanium additions of 1 ^ or less
The tensile data show small variations but do not show evidence of embriitiemeni due to gamma prime formation during 250 hr at 700degC (Table 619) In specshyimens from experiment 75-10 the wide range of trackshying behavior is apparent (Figs 665 and 666)
These tests have shown that several methods are availshyable for exposing metal specimens to tellurium The metal tefluride Cr Te 4 has an activity most consistent with our estimates of tellurium activity in an MSBR Specimens can be exposed to salt containing CrjTe 4 or exposed to vapor above the compound Tellurium metal at about 300degC has a vapor pressure of about I X 10 4
torr and appears IO provide a tellurium activity comshyparable to that expected in an actual MSBR The specishymens exposed thus far show that niobium is effective in reducing the extent of iniergranuiar embrittlemenl of Hastelloy N
615 EXAMINATION OF TeCen-l
B McNabb H E McCoy
The TeGen series of capsules was designed for studyshying the effects of tellurium and other fission products on metals The fuel capsule is a Vi-in-OD X 0035-in-wall X 4-in-long tube segment of the metal under
120
( c )
I OOIOf - _ I I J 0 2 9 M I
Fagtfcj64- CumdashjMiiun of imdashapamdashtm cmfcif bull l l i jNluj H lyye aBoyraquolaquoaoraquod wgt partial aitmdash11 erf tdNrimdash of 10 vm fat 250 br at 7WTC aad iliaan lo fraroarc at 2SC ltlaquoraquo Standard Hasfcttoy N that 4O5065i (142 crjckwrn a depth 416 raquoraquo IM modified Hastcfloy N containinc 08S^ Nb (aNoy 295) (10 crackson a depth 101 raquogt laquorgt modified Hastdloy N conlaaunK 082^ Ti 0427 Nb (alloy 470-786) (13 crackscm a depth 86 it 00x
Table 6 J I Rmdashfciwiof materials from expuimoH 75-10
Product of number of cracks and average epth
rnns) Alloy
number Concentration CJI
cracks 1 x rntci cm
epth
rnns) Alloy
number Ti Nb Other cracks 1 x rntci cm
4512 424 18 134 3245 421 219 104 3198 425 198 048 2328 405165 2157 425 198 048
713 298 20 336 413 10 113 209 348 062 047 Si 133 411 115 106 295 085 76 421543 07 45 345 045 022 Si
See Table 618 r detailed chemical aiulyicv
121
ltd)
( f )
I 0 2 5 M B I
Ff 65 Miami tpwmriw from expuwww 75-10 SpccmKru were cxrvwrd f-r 5n hr ji nn lt- ilt ihr apltlaquor iNiw irlluintm meiil JI nit C bullgt All- 424 iM jllgtgt i i rIjHn 45 II allot 4050 in allm 45 (gt alloy ^gtraquo A pohthrd Wfr
122
-1MS7t
(f) laquo0fllQH -
025 mm Fig 666 Stimti specimen from experiment 75-10expoatd tot 250 hraf 700Cfo fherapor above idmriwn meM it 300degC
(j) Alloy 413 (ft) alloy 348 ic)alloy 411 Irfraquo alloy 295 (ltbull) alloy 421543 if) all 345 A polithed IOOx
123
study The capsule is partially tilled with the MSRE-type fuel salt and irradiated in the ORR to produce fission products
The first experiment of this series involved fuel pins made of Inconei 601 standard Hastelloy N and type 304 stainless steel and the irradiation time was such that the amount of tellurium produced per unit area of metal in contact with salt was equal to that at the end of operation of the MSRE Some of the details of the postirradiation examination were described preshyviously2 2 A typical fuel pin is shown schematically in Fig 667 The segments marked A w re subjected to tensile tests using the fixture shown a Fig 668 The mechanical property data obtained roai the rings and the results of limited irtetallograpic examination were reported previously2 z More detailed mctallographic studies have been completed during this report period The segments marked B were used for chemical studies The salt from each segment was analyzed and the fission product distributions on the tube surface and a short distance into the tube were determined from two successive leach solutions The first leach used a verbodt solution (sodium vtrsenate boric acid and sodium citrate) which should have dissolved only residshyual salt from the metal surface The second solution was aqua regia and the time was sufficient to remove about
11 B McNlaquohb and II I McCoy IfSR Pnrmm Sununnu Pnifr Rip Feh gt tv~ ORM-5ltMpp 12 6
I mil ot the tube Both solutions were subjected to various chemical procedures to analyze for various nuclides and elements These results are partially anashylyzed and the results for tellurium will be discussed The tube segments marked ~C were retained for posshysible future studies
61 SI Metafognpaic Observations
Photomicrographs ot the three materials in the un-deformed condition are shown in Fig 669 Numerous voids were present near the surface of the Incopel 601 specimen to a depth of about 02 mil Voids were likely caused by the removal ot chromium from the alloy via reaction with U F 4 in the salt The Hasldloy S vrction shows no evidence oi chemical reaction with the salt The type 304 stainless steel shows some grain boundary attack to a depth of about 0_5 mil This was likely caused by selective removal of chromium along the grain boundaries The features in the type 304 stainless steel appear much like shallow cracVs and may have influenced the number of cracks that were observed in stressed samples of this material
Composite photomicrographs of the Inconei 601 rings after straining to failure are shown in Fig 670 Rings 2 and 4 from near the salt-vapor interface exhibit some evidence igt( attack but the other samples are almost entirely free of indications of chemical reaction
Photomicrographs of the deformed rings from the Hastelloy N capsule are shown in Fig 671 The count
olaquoM-oac n-ot
TTPt DESCRIPTION M O USE
bull VW bullbull IMG FOR HCCMAWCAL PROPERTIES
B fOU L E A C N (2 STEP
C StCTiQM TO K RETAINED
mdash EH0CAR
mdash A - i
4 -2 A-3 AN0 SALT LEVEL
z~ -laquo A-5
- S A-4 A - mdash C
mdash A - a A - raquo
mdash A- IO
mdash C
mdash A - M mdash A-12
mdash C
mdash A-13 mdash A-14 mdash A-15 mdash 8 mdash A - W mdash EMC CAP
f 667 Schematic docram of individMl feci pm jhowing the locaftoMof tat specimen
124
metaliographic sample indoles the fracture and an adjacent segment Since the fracture occurred at difshyferent locations the metallographic specimen contains varying amounts of inhomagcneously deformed mateshyrial For example Fig 67 I f includes a very small segshyment of homogenously deformed material whereas Fig 6 71 includes a relatively long segment As shown by the photomicrographs in Fig 671 and the data in Table 612 specimens from the vapor region (2-A-I) the salt-vapor interface (2-A-2) and rite bottom of the salt (2-A-l6) cracked most severely Three samples from other locations formed shallower cracks It is not known whether these differences are significant
Typical photomicrographs of deformed rings from the type 304 stainless steel capsule are shown in Fig 672 These specimens located on the inside surface had shalshylow cracks with an average depth of about 04 mil (Table 622) These cracks were rather uniformly distrishybuted in the samples from all four locations As noted in Fig 669 the unstressed specimen also contained cracklike features having a maximum depth of about 05 mil Hence the cracks in the stressed specimens may simply be the result of furti opening of features that are likely related to corrosion
6152 ClKiMcal Analyses for TeBormm
The lube segments designated B-l B-2 and B-3 in Fig 667 were subjected to several types of chemical analyses but only the results for tellurium have been analyzed in sufficient detail to report at this time The results for the three pins are shown in Tabic 623 The
Ffc668
0 Fixlare for ft leatinj rinji
of crack frequency shown in Table 622 was made in an effort to detect significant differences in cracking among the various specimens These counts are subject to numerous problems the main one being the inhomo-geneous distribution of strain within the sample In deforming the ring specimens in ihe fixture shown in Fig 668 the small portions of the ring located between the two parts of the fixture likely deformed very unishyformly but this length is very short relative to the total length The part of the ring that contacted the fixture likely deformed in some areas but was restrained in other areas by surface friction from the fixture The
Taate 6 J2 Smmmmy of crack frequency aad depth inToflMtiM for riant from TcGea-1
facts alaquo W M M t ID ratae at 25deg C
from TlaquoGCM fad Specimen nu iber
Crack frequency
(crack sin)
Crack depth (mils)
Average Maximum
2-A-l 480 080 20 2-A-2 450 II 22 2-A-4 410 060 12 2-A-5 480 058 12 2-A-8 MO 046 10 2-A-l 6 380 14 25
Type 304 (taMeu tted
1-A-2 160 04 12 3-A-4 310 042 10 3-A-8 260 036 10 3-A-I6 202 037 10
125
(a)
-J
(b)
(c) 20 40
- L - 1 _ 0001
60 MICRONS lt00 mdash SOOX -
laquo20 40
INCHES COOS
Fjj 669 Undeformed rings (ample No 9) from each TeGen fad pin near the middle of the fael aalL (a) Inconel 601 (ft) HuMelloy N(r) type 104 ttainlets jteel A polished 500x
600 inn
Ffc 670 Sample from Incond 601 fad put from TeGcit-l Kir failure al 25deg0 Portion of specimen exposed to fuel salt is on the I location A A (laquo) location A-5fr) location A-8 () location A-16
BLANK PAGE
Sch figure
j J u i u m l i i -Mi iWWLltLiWHt
126
a ten from (he location shown in Figr 667 and deformed to tide of cacti figure it Location A - l tftgt location A-2 ( r )
J
127
I Fig 671 Samples from Hwribr N fuel pin from TcGcn-l I bMurr M 25 ( Portim of specimen epltlaquoeraquol ilt fuel sill ii on l l location A-4laquo) lotjlion A-5 ltr) loolion A- i ft loci lion A-16
- l i bull gt i i glaquo i^_ a ^ bdquo ^ ^
ten from (he Uttattnas lthlaquown in I ijt A fc7 jlaquod deformed lltgt tide of ejch figure fat Location -1h) location A-2raquorgt
^
I
I t - -
BLANK PAGE amp bull
^bull
raquo-raquoMlaquoraquoWr
F)B 472 Sanata tmm lyat 301 itiialf steel fad pin ham Te atfunwed lo (xtmn at 25 C Poriwtt of specimen exposed lo fuel I locatio 4A to location AAIlt) location I6A
~^raquo-raquo i i T -- T-II bullraquoMraquoraquoMr5w mi j immmtmt^m
mm - bull - - bull bull bull - bull -
BLANK PAGE
mdash t - bull bull-bullbull -r^gatMtJliHwJraquoiWrraquovraquotj^WVu^-4-tgt- ~J(W~
fiMAmimraquom0mfMraquo-mdash- --- bullmdashmdash~~^--raquo bull
128
600 iim
M type 904 minim Heel fad pin from TlaquoClaquoM-I Rings taken from the locations shown in Fig 667 and C Portion of specimen exposed to fuel salt is on the lower side of each figure ltn Location 2A Ih) (lt) location I6A
2 ^ - m TMinfc
BLANK PAGE
128
600 pm
Ac locations shown in Fraquo 667 and bullf each fifiire It) Location 1A (ft) 3 L +ot nMtmgwmm
129
rlaquoJ3 raquo T e i bull Tea
nmHtrntMiaoam location
Type Concentration of bull T e C o ~ e ~ r t - o f bull bull T e nmHtrntMiaoam location
Type
bullpm total at JpnWg gcnr at i f f bull p a i o t a l o t a p a V l an or i a f
No 1 - IncondtOI 11 111
A B
S 2 J X 1 0 4tS X 10
4 2J7X 10
poundraquoSx 10 237 x 10
4 444 X 10
IB2 IB2 IB2
A B C
lt2J x 10 159 x 19 7laquoS X 10
4 r7SX 10 114 X 10
lt2J7 x 10 bull00 X 10 744 X 10
4 113 x 10- 45 x 10
IB3 IB3 IB3
A B C
pound53 x 10 27 X 10 247 x 10
4 345 X Iff 331 X 1 0
lt l 7x 10 34 X 10 143 X 10
4 57 X 10 99 x 10
No 2 - HasteHoy N 2raquo1 211
A B
lt M ( 10 749 X 10
4 3-Mx 10bull
lt I 4 4 X 10 497 X 10
4 094 X 10
2B2 2B2 2B2
A B C
raquoj x 10 29S X 10 7t X 10
4 Ml x 10 bull 5 i x 10
lt5 4x 10 202 X 10 594 X 10
4 3-7 X 10 24 x 10
2B3 13 2B3
A B C
lt54 X 10 laquol9x 10 34SX 10
4 422 x 10 bull 249 X 10 bull
lt 5 4 x 10 bull 05 X 10 393 X 10
4 U l x 10 141 x 10-
No 3 type 30 stainless start
3BI 3BI
A B
552 X 10 131 X 10
304 X 10 072 x 10bull
959 x 10 143 X 10
IS0X 10 3-44 x 10
3B2 3B2 3B2
A B C
954 X 10 25copy x 10 900 x 10
bull29 X 10
131 x 10
30 x 10 340 x 10
1042 x 10
bull J l x W iat x io 4laquoX 10
3B3 3B3 3B3
A B C
I M x 10 127 X 10 S3S x 10
116 x Icopy 044 x 10 74 X 10 bull
542 X 10 315 x 10 323 x 10
3-3 X 10 19 X 10bull 197 X 10
A denotes 100 a n aarntwn obuiotd by leaching the metal nanjlr m mbocit (soJimdash Tersenate boric an mdash I iiiinmdash cttnlel B i 100 cm sowlion obtained by l u i l raquo n the metal amftt m raquoraquobullraquo reeja lo remore aboat I M i of nartaLC denotes 100 cm sotation obtained by distorting aboal I g of salt in Mtric icid ( I JO saturated with bone acid Counts for iniiiidojl Radioes gram in dionfegralions pei Minnie (dpntt total for chemistry types A and Band dpM per graa of salt for type C daroMBry saMpfc These cooam ace laboratory w n t u i and abject to sctta corrections omkh lane not been none cThese concentrations are espitjatd as grams of the particnlar nncMr per CM of Metal sartace for cheaaatry ample types A an B ant ar exams of nailidc per gram of alt for chemistry siMpli type C The nines hare been court nd back to the conrfcjsiBn of die H amnion Concentration flwinglit safTiciently low to be ignore
sample numbers ending with I (ie I B l 2B1 and 3BI ) designate the material that came from the fuel pin wall exposed to the gas space above the salt The ample numbers ending with 2 designate material that came from the fuel pin exposed to the fuel salt just below the sail-gas interface and the sample numbers ending with 3 designate material that came from the portion of the fuel pin exposed to fuel salt near the bottom of the capsule Solutions were prepared for analysis by leachshying metal samples of each tube in verbocit to remove residual salt (type A solution in Table 623) leaching the rings in aqua regia (type B solution in Table 623) and dissolving about I g of salt removed from the metal rings in nitric acid (type C solution in Table 623) These solutions were counted to determine the amounts of J 7 T c and T e present The direct results of
these analyses are presented in Table 623 but cannot be interpreted directly because a number of corrections have not been made The data have been corrected as well as possible o reflect the concentration of each nuclide at the end of irradiation The concentrations for the leaches from the metal specimens are expressed as grams per square centinpoundtcr of tube wall exposed to the fuel salt and the concentrations for the salt samples are expressed as grams per gram of salt
The ORIGEN code was used by Kerr and Allen to predict the concentrations of tellurium isotopes that should have been present These calculations have been used extensively in the subsequent analysis of the data Table 624 compares the quantities of 7 raquo T e and l l laquo m T e f o o n ( j m | h e ( n r e e f ^ i p j p W j ( n thoje p r e
dieted to be present by the ORIGEN calculations For
130
each fud pin the one sample taken of the tube in the gas space was assumed to be typical of that region and the two samples from the salt-cowered parts were avershyaged to obtain a typical value for the salt-covered region As shown in Table 6 2 4 generally about 20 of the T T e and 1 T e was found The percent of tellurium found in the Incond 601 capsule was apprecishyably higher due to the higher amount found on the salt-covered metal surfaces
There are several possible ex|)lanations why the conshycentrations of I 7 T e and 2 T e found are only about 20 of those produced One possibility is that the amounts calculated arc too high This appears not to be the case but the calculations wiQ be checked further The most likely explanation is that the add leach was not sufficient to remove all of the tellurium from the wall The tube segments were suspended in the acid with the made and outside surfaces of the tube wall exposed as well as the cut surfacr on each side of the ampin tube segment Based on the weight changes obshyserved and the assumption of uniform metal removal the thickness of metal removed appears to be about 08 mil Since the cracks extended deeper than 08 mil in the HasteDoy N the tellurium likely penetrated deeper than did the leaching solution However the cracks in the other two materials were very shallow and the
08-roii dissolution should have recovered a higher fracshytion of the teflurium if one can equate the depth of cracking to the depth of tellurium penetration The results in Table 6 2 4 show no evidence of a systematic variation in the percent recovered from the three tubes Several possible explanations for the apparent discrepshyancy in the quantities of teflurium generated and that actually found are being investigated but none appears reasonable at this time
The concentrations of 2 7 T e and 2Te found in the salt can be used to predict upper limits for the solubility of tellurium in fuel salt under these condishytions The I 7 Te nuclide concentration in the a l t ranges from 114 X 10 to 131 X 10 g pet gram of salt (Table 623) The ORIGEN calculations were used to estimate the ratio of l 2 T Te to total tellurium and this ratio was used to convert the above concentrations of T T e to total teflurium concentrations of 007 to 083 pom Smiariy the concentration of 2 T e ranged from 45 X 10 to 648 X 10~ g per gram of salt and these correspond to total teluriurn concentrashytions of OJOS to 113 ppm The low values in both cases were noted in the Inconel 601 pin and the higher values were observed in the type 304 stamhts steel pin The concentrations m the HasteSoy N pin were only slightly less than noted for the type 304 stainless steel pin The
TaMt624 A w o mdash l o f T CnhnsM bull n r i o t i kKSfuOtv ol fed pint tmm TcGea-I (a)
IncondoOl HastdloyN Type 304
mje bull T bull gtraquorT e T e mje bull T bull gtraquorT e T e bull T e bull T e
Salt 41 x 10 bull 13 x 10 - 10 x 10- 35 x 10 M X 10 74 x 10 Metal-vapor space 14 x 10 24 x 0 21 X 10 50 x 10 2Jgt X 10 i2 x ie- Metal-sll covet at 17 x 10 23 x I t r 78 x 1 0 25 x 1 3 44 X iW 39 x 10 T
Total fomd 19 X ltgt-bull 27 x IC II x 10-bull 3 5 x 10 laquo 2 x 10 23 X 10 Total formed 3 A 2 x 10 bull 134 x I 0 f 40 x 10 148 x 10 36 X 1 0 134 x 10 laquo ferccM found $2 20 2raquo 23 23 17
of frnl MM hum TlaquoGcn-l (10 aon)
Location Incoiwi bull 1 HastcftorN Type 304
is sled Location bull T e raquo T laquo T e bull T e
Type
bull T e raquo T laquo T e bull T e T e T
Mctal-vapor space Bl MetaMaii location B2 Metal-salt locaiion 83 Avenge if foul yield evenrr distributed
257 bull 75 345
112
446 113 576
413
3J6 152 422
123
94 376
IS 1 456
376 229 095
112
214 I M 103
413
131
higher chromium concentration of the Inconet 60 may have caiced the lower tellurium concentration in the fuel salt
The con-entrations of l l l m J e and t 2 9 m l e are expressed in Table 625 in terms of grams per unit surshyface area There appear to be significant variations within each capsule but there is no consistency beshytween the various pins The high value for ITe in the vapor space of the type 304 stainless steel pin is likely anomalous since the n T e t$ not i s high Thus ai this time we conclude that the tellurium is distributed uniformly over the entire surface area of the pin
616 SALT PREPARATION AND FUEL PIN FILLING FOR TeGea-2 AND -3
M R Bennett A D Kelmers
The purpose of this portion of the TeGen activity is to prepare purified MSRE-type fuel salt containing bulliiV and to then transfer a known quantity of this salt into fuel pins gtr subsequent irradiation in the ORR One batch of purified salt will be prepared and used in two filling operations to fill two sets of six fuel pins each identified as TeGen-2 and TeGen-3 Similar activishyties in 1972 to fill the fuel pins used in experiment TeGen-I have been previously described2 3 To MSRE-
type fuei carrier salt containing LiF-BeF-ZrF4
(647-301-52 moleltv)sufficient U O j and 2 U F 4
were added to produce a fmji composition of LiF-BeF -Z r F 4 - I 3 3 U F 4 - 2 U F 4 63J08-29J5-5 O7-1 0O-15O mole ) after hydefluorination to reduce the oxide content The uranium will be reduced by hydrogen or bv beryllium if necessary to a U3 content of 10 to 18 and a measured xlume of salt will be transferred into the fuel pins The design permits obtaining a preshydetermined volume in the pins by flushing through an excess salt volume and then blowing back the salt in the upper portion of the pins to leave a predetermined volshyume
The equipment in Building 4508 used previously for this work was reactivated and modified where approprishyate A safety summary and step-by-step operating proceshydure have been prepared and approved During the latshyter part of this i port period the salt components were charged to the salt purification vessel and a 364ir hydrofluorination at 600degC was completed Both filshytered and unfiltered samples were obtained after hydroshyfluorination in copper filter sticks After analytical results indicating satisfactory removal of oxide liave been received hydrogen reduction of about 1 of the UF 4 will be carried out
23 R L Sain J H Suffer H E McCoy and P N HjabcnrcKh MSR htrprnm Srmmcvni trofr Rep Aug il 1972 ORNL-4832 pp 90 9
7 Fuel Processing Materials Development
J R DiStefano H E McCoy
The processes that are being developed for isolation of protactinium and removal of fission products from molten-salt breeder reactors require materials that are corrosion restrtint to bismuth-lithium ind inoiiev fluoshyride solutions Past experience has indicated that alshythough their solubiities in bismuth are low iron-base alloys mass transfer rapidly in bismuth at 500 to 700 SC The most promising materials for salt processing are molybdenum Ta-10^ W and graphite Molybdenum has been tested in a wide range of bismuth-lithium solushytions for up to lOjOOO hr and has shown excellent comshypatibility Thermodynamic data and literature reports indicate that molybdenum will also be compatible with molten fluoride mixtures
Ta-10 W also has excellent compatibility with bismuth-lithium solutions but tests are required to measure its compatibuity with molten fluoride salts A thermal convection loop has been constructed of Ta-10 W and a test with LiFBeF2-ThF4-UFlaquo (72-16-117-03 mole ) wffl be started during the next reporting period
Graphite has shown excellent compatibility with both bismuth-lithium solutions and molten salts Although no cheruicai interaction between bismuth-lifcisas solushytions and graphite has been found the hqtsd-KjsuS solushytion tends to penetrate the optn porosity of graphite Recent tests have evaluated the extent of penetration as a function of structure of the graphite and the Uthium concentration of the bismuth-hthium solution Dynamic tests of graphite with bomuth-tithium have thus far been limited to quartz oop tests circulating K - 0 J 0 I wt ( 0 3 at ) Li During the report period a test was
completed in which graphite samples were exposed to Bi-24 w 1 (42 at vt) Li in a molybdenum thermal convection loop for 3000 hr at 600 to 700degC
71 STATIC CAPSULE TESTS OF CRAPHTTE WITH BISMUTH AND
MSMUTH4JTHIIJMSOIIJ110NS
J R DiStefano
Samples of graphite with varying densities and pore diameters were exposed to H-017 wt (48 at ) Li and K - 3 w t (48 at ) Li in capsule tests for 3000 hr at 650degC Two of the graphites (Table 71) were pitch impregnated t j increase their densities and reduce their pore sizes1 The relatively high densities of these graphshyites indicate that impregnation was effective but the pore size distribution in the samples shows that some of the larger pores were unfilled or only partially fdkd Specimens were graphite rods 6 mm (024 in) X 381 mm (15 in) long that were threaded into an ATJ graphite holder The specimens and holder fit into a graphite capsule which contained the bismuth-lithium solution (Fig 7IK The laquoniire aoembiy was sealed in a suhwVss steel outer capsule by welding in argon Samshyples exposed to 61-017 wt (48 at ) Li showed little evidence of penetration except in low-density areas (Fig 12) Samples exposed to Bi-3 wt (48 at ) Li were penetrated more uniformly and the depth
1 Al grapfcilei were fabricated by C ft Kennedy of the Carbon and Graphite Groap Merab and Ceramics Dmnon OftNL
TaMr7l P f t trjtnPnt 01 yinpfcitt fcy lNpMvtfc4ilfcM McapfritttattlbrJtei b r a t t s r c
MISflMM
Graphite demtty Igcml
Ranee of porediam
Maximmn pore diameter chat
conrribnies 10 to total pDtoaly
ltraquogt
nuefration (mils) bulldentiOcatiow
demtty Igcml
Ranee of porediam
Maximmn pore diameter chat
conrribnies 10 to total pDtoaly
ltraquogt K 0ITOU m 3Li
334K 44-25 K 33-3SK 44-26K 44-23K
IM IM 190 ISO 159
01 1 01 2 01 2 01 35 OI 4 5
1 12 I J I J 45
0 5 0 17 8 0 5 5 0 -2 8 0 2 15
Impregnated
NonvMrform penetration in one -gtr two area only
132
133
0MlaquoL-0laquoCrS-l4M9
Flaquo 71 GapMe (bimdasheh lithww) opiate fed asmMy
of penetration increased with increasing pore size and decreasing density Results from previous tests have been inconclusive as to tnr effect of lithium concentrashytion in bismuth on penetration of graphite In the curshyrent series all graphites were penetrated tc a greater extent by K - 3 wt (48 at ) Li than by Bimdash017 wt 9f (48 at ) Li Tests of 10000 hr duration with these graphites are continuing
72 THERMAL GRADIENT MASS TRANSFER TEST OF GRAPHITE IN A MOLYBDENUM LOOP
J R DiSuiano
Although graphite has low solubility in pure bismuth (less than I ppm at 600degC) capsule lest results have shown that higher carbon concentrations are present in Bi -2 wt (38 at ) Li and K-3 wt (48 at ) Li solutions after contact with graphite To avoid the joining proolems associated with fabrication of a graphshyite loop a molybdenum loop was constructed and interlocking tabular giaphite specimens were suspended
in the vertical hot- and cold-leg sections2 In addition to mass transfer of graphite from hot- to cold-leg areas penetration of graphite by bismuth-lithium and mass transfer between graphite and molybdenum were evalushyated
721 WcajMCkaafes
The loop (CPML4) circulated K-24 wt (4 at 3 ) Li for 3000 hr at 700degC (approximately) maximum temperature and 600degC minimum temperature Weight changes in the graphite samples are given in Tables 72 and 7 J After the bismuth-lithium solution was drained from the loop the samples were removed and weighed (after-test column in Tables 12 and 7 3 ) Subshysequently they were clltmdashned at room temperature in ethyi alcohol and in an hO-HNOj (100 ml H 2 O-30 ml 90 HNOj) solution to remove bismuth-lithium adhering to the surfaces of some samples Samples from the cold leg were weighed and then kept in air for two days prior to the alcohol treatment After soaking in alcohol these samples showed larger weight gains than the after-test weight gains and this is attributed to reacshytion of lithium in the sample with moisture in the air during the two-day period AD samples showed large weight gains (33-67) and gains in hot-leg samples were on the average larger than those in the cold-leg samples
122 Compositional Changes
Graphite samples were analyzed before and after treatment with H 2 0 - H N 0 3 and the results are shown in Table 74 These results indicate that bismuth was primarily responsible for the large weight increases and that samples picked up molybdenum but treating them with H 2 0-HNOj completely removed the molybshydenum An electron-beam microprobe analysis of a graphite sample before acid cleaning showed that molybdenum was present on the outer surface of the specimen (Fig 13) Chemical analyses of other graphite samples after acid cleaning are shown in Table 75
Analysts of bismuth-lithium samples from the loop are shown in Table 76 For sampling the hot leg was sectioned so that one sample came from the surface that was in contact with the molybdenum tube wall while the other sample was taken from the interior of the section away from the wall The concentration of carbon in the melt was highest in the sample from the hot leg and both molybdenum ami carbon concentra-
2 i R DiStefano MSR Program Semimnu frofr Rep Pth 28 1975 ORNL-5047pp 140 41
li-3 11 V-IMIOi
-I5H raquobull Mplaquolaquom
F| ) NtMlnltpnorpirMttuiriMwManorMnKluHurinfMltiiid Itlhlum InMwiulli tuniliiiltgtnraquo IIHNI hr M fcjnV
13S
r7J iraquoATJ bull CML4
Wclaquofci If) Welaquofci bullKVU9 I
n mdash t r i bullefore Mi l
After m i
After
bull U k n t w l
After
raquoH04mo
Welaquofci bullKVU9 I bullefore
Mi l After m i
After
bull U k n t w l
After
raquoH04mo ltlaquo) laquoltgt
5 0 4 5 3 0S244 0 1 2 2 0704 02443 54 7 05220 0970 0 95 0S29S 0 3071 59 04494 09551 0933 0X298 OJ304 6
| l gt 0 400 0959 0919 07944 03144 I I 0432 0 3 3 9 0S3O3 07102 0277 4 12 0 4 5 09302 0923 079 03075 7 13 04753 0979 0974 0 7 02933 2 1 0432 09175 09152 075 0302 5 17 04742 09099 0905S 0794 02952 62 IS CS070 09005 0 J 9 5 07975 0290S 57 1 04709 0-raquollaquo9 0142 0 7 1 02459 52 zo 0539 091 M 09149 0 107 0 J 7 J 51 21 0513 OK52 0 J 2 9 072 02453 4 22 0 5 I M 0 M99 0 M59 0759 0J407 4 23 0-539 09103 090 07475 02067 3 24 03405 0 5 4 5 0 4 9 7 07235 01130 33
Top of IKM ley I
Kwlion of hoi leg M laquo | I J M I
rare 0 700C Q0-2OC
Vclaquofti it)
Wclaquoht After Wclaquoht
n m b r t Before After stjfldiHC in am tot two day
After
H 0 -HNO
mcreaK n m b r t
lev lejl
stjfldiHC in am tot two day
After
H 0 -HNO ltIgt I
makohol
27 04 4 0749 0722 0 4 0 01794 39 2 0421 0 2 4 OS4I2 0 2 0 01439 30 29 04717 07793 07913 06433 0 I 7 - 36 30 0477 0713 07239 0291 0151$ 32 31 044 07209 07315 0 3 9 a i 5 4 8 32 32 0427 0729 07744 0647 01 raquo20 3 33 047ft 07193 07 TOO 0331 01543 32 34 0470 0756 0772 0653 012 39 35 0424 073raquo2 0745 0 2 9 0 016 3 3 0423 0749 0759 0343 01520 32 37 0447 07331 07432 0 239 01572 34 3S 04713 07513 0719 0641 01705 3 39 04745 0749 070 0 506 0171 37 40 042 0725 07390 0233 01605 35 41 04725 0745laquo 07J53 0 419 01694 3 42 04100 07427 07525 0652 01726 36 4 3 0476 0720 07401 0647 01712 3
Top of onM leg lempmlvrc 60 60 C ftotlom of cold ley temperalarc 620 630C
136
aMr 74 n a m e d bull bull bull bull bull bull bull ttVli
S jmr t rm HRJIWT Coadiiion Cuacramnunlraquo i
S jmr t rm HRJIWT Coadiiion 3i Li gt
4 (hH WTraquo 4 tbraquort llaquogt
i Ui4d iclt
l a t k a a r d Acid cftcaAGd (bullctnacd Atid ckaacd
4 3 43 40
bull gt 0J I 04
bull11 ltlaquolOI
bullMM ltlaquoMU
tions were higher than were found previously in quart loop tests circuiting Bi-OjOl wt (03 n bulllt Li Quartz loop test 11 contained molybdenum samples and analysis of the bismuth-Uthium solution after test shewed that t contained 25 ppm molybdenum Quartz loop 8 contained samples of three different grades of graphite and the bismuth-tiimum solution contained 10 to 15 ppm carbon after the test
J O B Caiwt j ad L ft Trotter MSR i Awfr Rep Air _ 1971 OKSL-4 p i - 3
V1330SS
BACKSCATTERED ELECTRONS
- - - Oraquo J
V
8 i M a X-RAYS Me L X-RAYS
Ffcgt 7J EMCWIM kmn) laquoeaaninj M H J M r laquoapnlaquo taawnf to Mnmrth Vnw IA) a backmttcrcd electron picture of sample tarface dark material n tnpfcitc and bright material is bianulh and malybdemHM as indicated by iff)and O
117
Tank 7 3 C k a m anakwaaf p i j i i i r bull bull | l i r f c mdash C F M L - 4
bull bullbe U Mo
1 Hot kg 37 0J5 ltOJraquol ltraquo H o i k s 42 044 lt0OI
15 H o i k 4 04 ltO01 l raquo Hocks 3 0 J 5 lt 0 0 1 24 Hotks 2i 025 ltOOI ^ T C o M k f J 0 3 5 ltO0 I 31 C o M k f 21 0 2 5 lt00I 3 C o M k f I t 02 ltoot 42 CoMkc 23 02 lt0Jraquo
Sampio plusmni deaneu m H OMNO prior to a i r
Tabk7 A ^ s t t t a M M i
CoaceaiDiMt
Sample location C ippa l
Mo tppau
Li fit
Hot k f icowl Kof kg iflwfaotf r
CoM kg loner
43 10 24
17 102
4
23 3 0 1
On a raghl bam Interior tampk
Surface simple in contact raquonb molyb i fcmdash rabe laquoaH
Selected graphite samples from hot- and cold-leg regions are shown in fig 74 The white phase distribshyuted throughout the samples is bismuth these samples were add cleaned and it is evident that bismuth was dissolved from the area near the surface Molybdenum samples from hot- and cold-leg regions are shown in Fig 75 Surface layers measuring 0015 to OJ025 mm (0 6 -1 mil) thick were found on the hot-kg sample In some areas ttwie was a single layer while a double layer was found in other areas Electron-beam mkroprobe analysis indicated the single layer andor outer layer to be primarily molybdenum This layer was much harder than the base metal (1000-1200 DPH compared with about 200 DPH) indicating that it is probably MojC Where there is a double layer the outer layer appears to be MojC but the inner byer n primarily bismuth One explanation is that the MojC layer cracked andor spailed allowing the entry of bismuth which did not drain when (he lest was terminated The molybdenum sample from the cold leg also exhibited a surface layer
i o raquo f l u C mm t h k k i gt i i 33S SSSH3 S CCSSpSKBOS to that found in the hot leg Samplrs of molybdenum from hot and cold legs have been submitted for chemishycal analysis
The prindtMl objective of this experiment was toeval-uate temperaiure-gtadieai mass transfer of graphite in bismuth umijiuiug a retainer high concentration of lithium However mass transfer data were obscured by the gross pickup of bismuth by the graphite samples Previous capsule and quartz loop tests with ATJ graphshyite had indicated much less intrusion of the graphite by bismuth than occurred in the molybdenum loop test This suggests that the permeabihty at ATJ graphite to bisnush-hdnum does not depend simply on the po-rc^y of the graphite It is generally accepted that some fracioa of the pores in graphite is effectively sealed off 7uraquo contributes nothmg to flow Therefore the conshynected pore system controls the penneabraty The shape of the connected pores influences the type of flow and die length of the path the fluid takes through the sample For a nonwettiug liquid the external presshysure forcing the liquid into the pores 1 must overshycome the surface tension of the liquid This defines a critical pore radius r( and unt l the pressure exceeds the value given by
lrraquo=27costfr c ltgt
where y is the surface tension and 9 the wetting angle the pore cannot support flow Thus for a given - I f rc is the minimum pore size that w H be penetrated In both the metal and quartz thermal convectica loops IT is determined by the argon overpressure ( lt l atm) and the height of btsmmh-fcthium solution above the sample and these wne essentially the same in both types of tests Temperature affects both a and 9 but all o( the tests were operated under similar thne-temperature-^r conditions Graphite samples used hi the quartz too tests had almost four limes the surface area o f the tabushylar specimens used in the current test but they were almost three times as thick The larger surface area of the quartz loop specimens should have increased the relative amount of bismuth-lithium intrusion but the greater thickness of these samples would reduce the pershycentage increase ATJ graphite samples from the quartz loop tests increased in weight by 01 to 06 wt ar far less than the 30 to 67 wt increases noted hi samples from the current loop test Thus specimen geometry alone does not seem to explain the differences noted However the surface tension o and wetting angle 9 were
138
3
i 8
a
139
Y-I33405
- n r fimfir nriiiTii ifiari Bottom of Hot Leg 600C Bottom of Cold Log 620C
f 75 MolyMniBin tube waN from thermal comectkm loop CPML-4 thai cin slated Bi-24raquo Li and contahnd graphite ^CCMCHS
probably different because the lithium concentrations of the bismuth-lithium solutions were different and molybdenum was present in the current test It is posshysible that the presence of molybdenum on tie surface of the graphite had a marked effect on the contact angle 0 fn an earlier series of tests the bismuth content of graphite specimens was much higher when they were tested in molybdenum capsules instead of graphite capshy
sules4 Accordingly data on the wetting of graphite by-bismuth containing lithium and other constituents of processing solutions would be useful for predicting the resistance of graphite to penetration
4 J R PiStefano and O B CavmMSR Profnm Semumnu Pmgr Rep Feb 2K 1975 ORNL-SM7 pp 137 39
Pan 4 Fuel Processing for Molten-Salt Reactors
J R HightowerJr
The activities described in this section deal with the development of processes for the isolation of protacshytinium and for the removal of fission products from molten-salt breeder reactors Continuous removal of these materials is necessary for molten-salt reactors to operate as high-performance breeders During this report period engineering development progressed on continuous fluorinators for uranium removal the metal transfer process for rare-earth removal the fuel recon-stitution step and molten salt-bismuth contactors to be used in reductive extraction processes Work on chemistry of fluorination and fuel reconstitution was deferred to provide experienced personnel for the prepshyaration of salt for the TeGen-2 and -3 experiments (Sect 617)
The metal transfer experiment MTE-3B was started In this experiment all parts of the metal transfer process for rare-earth removal are demonstrated using salt flow rates which are about 1 of those required to process the fuel salt in a lOOO-MW(e) MSBR This experiment repeats a previous one (MTE-3) to determine the reasons for the unexpectedly low mass transfer coeffishycients seen in MTE-3 During this report period the salt and bismuth phases were transferred to the experishymental vessels and two runs with agitator speeds of 5 rps were made to measure the rate of transfer of neo-dymium from the fluoride salt to the Bi-Li stripper solushytion However in these runs the fluoride salt was enshytrained at low rates into the LiCl which resulted in depletion of the lithium from the Bi-Li solution in the stripper Fuel-salt entrainnient was unexpected since no entrainment was seeii in experiment MTE-3 under (as far as can be determined) identical conditions The Measurement of mass transfer coefficient in these first tvo runs was not compromised by the cntrainment The measured mass transfer coefficients were lower than
predicted by literature correlations but the values are comparable to those obtained from experiment MTE-3
Mechanically agitated nondispersing salt-metal conshytactors of the type used in experiment MTE-3B are of interest because entrainment of bismuth into the fuel salt can be minimized because very high ratios of bisshymuth flow rate to salt flow rate can be more easily handled than in column-type contactors and beczuse these contactors appear to be more easily fabricated from molybdenum and graphite components than are column-type contactors Attempts were made to measshyure entrainment rates of fluoride salt in bismuth and entrainment rates of bismuth in fluoride salt under conshyditions where the phases were not dispersed and under conditions where some phase dispersal was expected These measurements were made in the o-tn-diam (01 S-m) contactor installed in the Salt-Bismuth Flow-through Facility The results indicate that mild phase dispersal with in concomitant high mass transfer coeffishycients night be allowable in the reductive extraction processes We are continuing development of methods for measuring mass transfer coefficients in mercury-water systems to learn how to scale up contactors which would be used with salt and bismuth
A nonradioactive demonstration of frozen salt corshyrosion protection ir a continuous fluorinator requires a heat source that is not subject to attack by fluorine in the fluorinator To provide such a heat source for future fluorinator experiments we have continued our studies of autoresistance heating of molten salt During the report period we have completed new equipment for studying autoresistance heating of molten salt in a flow system similar to a planned continuous fluorinator exshyperiment three preliminary runs have been made with the equipment The design was started for a facility for developing continuous fluorinators and equipment is
140
141
being installed for an experiment to demonstrate the effectiveness of frozen salt for protection against fluoshyrine corrosion
The uranium removed from the fuel salt rraquogt fiuorina-tion must be returned to the processed salt in the fuel reconstitution step before the fuel salt is returned to the reactor An engineering experiment to demonstrate the fuel reconstitution step is being installed In this experishyment gold-lined equipment will be used to avoid introshyducing products of corrosion by U F and U F S Alternashytive methods for providing the gold lining include elecshytroplating and mechanical fabrication The choice beshytween the two depends on availability of gold from fcRDA precious-metal accounts and the price of gold from the open market Instrumentation for the analysis
of the vessel off-gas streams has been installed and is being calibrated
Future development of the fuel processing operations wdl require a large facility for engineering experiment A design report is being prepared to define the scope estimated design and construction costs method of accomplishment and schedules for a proposed MSBR Fuel Processing Engineering Center The building will provide space fcr preparation and purification at salt mixtures fcr engineering experimenis up 10 the scale required fcr a I0OO-MW(e) MSBR and for laboratories maintenance areas and offices The estimated cost of thrs facility is SISjOOOjQOO and authorization is proshyposed for FY 1978
R Engineering Development of Processing Operations
J R Miditower Jr
81 METAL TRANSFER PROCESS DEVELOPMENT
HC Savage
During this report period the salt and bismuth solushytions were charged to the process vessels of the metal transfer experiment MTE-3B Two experiments were completed in which the rate of removal of neodymium from molten-salt breeder reactor fuel salt (72-16-12 mole LiF-BeF 2-ThF 4) was measured
The MTE-3B process equipment (Fig 81) consisted of three interconnected vessels a 14-in-diam (036-m) fuel salt reservoir a 10-in-diam(025-m)salt-metal conshytactor and a 6-in-diam (015-m) rare-earth stripper The salt-metal contactor is divided into two compartshyments interconnected through two 05-in-high lt 13-mm)
I H C Savage Bngmeenng Development Studies for Molten-Sat Breeder Reactor Processing Xo -0 ORNL-TSM870 (in preparation)
by 3-in-wide (76-mm) slots in the bottom of the divider Bismuth containing thorium and lithium is cirshyculated through the dots Thus fluoride fuel salt was in contact with the Bi-Th in one compartment and LiG was in contact with the Bi-Th in the other compartshyment The stripper contains lithium-bismuth solution (5-95 at ) in contact with the LiCl Mechanical agitashytors having separate blades in each phase in the conshytactor and stripper were used to promote mass transfer across the three salt-metal interfaces The fluoride fuel salt was circulated between the reservoir and contactor by means of a gas-operated pump with bismuth check valves The LrCl was circulated between the stripper and contactor by alternately pressurizing and venting the stripper vessel
The bismuth-thorium phase was circulated between the two compartments of the contactor by the action of the agitators and no direct measurement of this flow rate was made during the experiment however measshyurements made in a mockup using a mercury-water system indicated that the Bi-Th circulation rate between
ORWL-06-71 1471
AWTATORS-
LEVEL ELECTRODES
LiT-raquoF--TMU Li-a
FLUORIDE SALT
RESERVOIR
SALT- KCTAL CONTACTOR
M M EARTH STRIPPER
F 81 Flow diagram for metal trmrfcr experiment MTC-3
142
143
the two compartments should be high enough to keep the concentration of rare earths in both compartments essentially the same2 This was found to be the case in the two experiments in MTE-3B
In this experiment neodymium is extracted from the fuel carrier salt into the thorium-bismuth solution Next the neodymivm is extracted from the thorium-bismuth into molten LiCI and finally (he neodymium is stripped from the LiCI into bismuth-lithium alloy
Operating variables in the experiment are
1 the flow rate of the fluoride fuel salt between the fuel salt reservoir and the contactor
2 the flow rate of the lithium chloride salt between the contactor and the stripper vessel
3 the degree of agitation of the salt and bismuth pluses in the contactor and stripper
4 the amount of reductant (lithium) in the bismuth phase in the contactor
The operating temperature of the systen is ^-650degC Overall mass transfer rates for representative rare-earth fission products are determined by adding the rare earth to the fluoride fuel salt in the reservoir and observing the rate of transfer of the rare earth across the three salt-bismuth interfaces as a function of time by periodic sampling of all phases
2 H O Weeren and L E McNcese Engineering Developshyment Studies far Molten-Sail Breeder Reactor Processing So 10 ORNL-TM-3352 (September 1974) pp 57 59
[taring the course cf the experiments the concentrashytions of neodymium in each phase were deteiiaiacd by counting the 053-MeV gamma radiation emitted bv 4 T N d tracer added to the neodymium origmaBy in the fuel salt This provided a rapid method for fallowing the transfer rate More accurate data necessary for calculatshying the overal mass transfer coeffiaeats at each of the three salt-metal interfaces were obtained by analyzing samples of the salt aM bismum phases for total teo-dymium via an isotonic dilution mass spectrometry technique Use of this technique avows measurement of neodymium concentrations as low as OJOI ppm (wt)
811 of Salt J to Metal MTF3
The quantities ot salts and bismuth charged to the process vessels of experiment MTE-3B are listed in Table 81 AD internal surfaces of the carbon-steel vesshysels were hydrogen treated at 650degC for V7 hr to reshymove any oxides prior to the addition of the salt and bismuth solutions The auxiliary charging vessels used in the additions were also hydrogen treated Subsequently a purified argon atmosphere was maintained in all the vessels to prevent oxide contamination (via ingress of air or moisture) of the vessels and process solutions
The charging vessels were IO-in-diam (0_25-m) carboa-steH vessels o f about 22 liters (0022 m 3 ) in volume equipped with electric heaters for melting the salts and bismuth Nozzles and access ports were pro-
Tabie8l Qwtit iet ot salts and tnsmmtk for o u M i w f t MTE-3B
Material Vessel Volume at
650C (liters)
Wesgh (kg) f-moles
Fluoride fuel salt Reservoir 294 970 5lt (72-16-12 mole LiF-BcF -ThF)
Fluoride fuel salt Contactor 31 102 161 (72-16-12 mole LiF-BeF-ThF)
Bismuth-thorium | M 500 ppm (wt) Th Fluoride salt 29 276 132 MO ppm Li| side of contactor
Bismuth-thorium [M500 ppm (wl)Th LiCI side of 35 33 161 M 0 ppm Li| contactor
Lithium chloride Contactor 29 43 101
Lithium chloride Stripper 38 56 132
Bismuih 5 at lithium in Stripper 43 418 200 stripper
Demiliev at 650C fluoride fuel salt 330 gcc LiCI = 1 AS gcc Bi 96 gcc Mole weight = 632 g
144
video for the addition of the salts and bismuth argon and hydrogen purge gas ones and hues required to transfer the salt and bismuth phases into the process vessels
Bismuth hydrogen treated in the charging vessel to remove oxides was the first material to be added to the contactor The fluoride fuel salt was then contacted in the charging vessel (using argon sparging) with a bismclaquoi-OIS wt thorium solution (50 of Th satushyration) for several days prior to transfer into the fuel-salt reservoir and the fluoride salt compartment of the contactor Thorium metal (01197 kg) was then added to the 614 kg of bismuth in the contactor This quanshytity of dtorium is about 50 of the amount that would be soluble and was calculated to produce a lithium conshycentration ot ^-40 ppm (wt) in the thorium-bismuth phase in the contactor based on previously reported data1 on the distribution of thorium and lithium beshytween molten bismuth and fluoride fuel -alt
FoBowing the additions of bismuth to the contactor and the fluoride fuel salt (72-16-12 mole LiF-BeF2-ThF 4) to the contactor and fuel-salt reservoir a new charging vessel was installed for makeup and charging of the bismuth-5 at lithium to the stripper and the LiCI to the contactor and stripper First bismuth was added to the charging vessel and was hydrogen treated to remove oxides by sparging with hydrogen at v-oOOC (873degK) for laquoraquo7 hr The charging vessel contained 6787 kg of bismuth to which was added 0120 kg of lithium metal to produce the bismuth-5 at lithium for the stripper Part of the bismuth-5 at lithium solution (41 amp kg) was then transferred into the stripper vessel
Thorium metal (0109 kg) was added to the 26 kg of bismuth-lithium solution remaining in the charge vessel and 1588 kg of LiCI that had been oven dried at 200degC (473degK) was added to the charge vessel The bismuth-lithium-thorium and LiCI phases were sparged with argon using a gas-lift sparge tube for four days The LiCI was then transferred into the LiG side of the conshytactor and the stripper vessel
The salt and bismuth solutions were filtered through molybdenum filters [^30 u (30 X I0~ 5 m) in pore diameter] installed in the transfer lines during transfer
- from t^e charging vessels into the MTE-3B process vessels
812 Run Nd-I
For the first run in MTE-3B 3300 mg of NdF (2360 mg of Nd) was added to the 97 kg of fluoride fuel salt (72-16-12 mole LiF-BeF2-ThF4) in the fuel salt resershyvoir on June 6 1975 The neodymium contained 722 mCi of TNd tracer (tVi - 11 days) at the time of
addition The neodymium concentration in the fuel salt in the reservoir was calculated to be 24 ppm (wt) which approximates that expected in the fuel salt of a single-region lOOO-MWie) MSBR Neodymium was chosen as the representative rare-earth fission product for the first series uf experiments in MTE-3B for several reasons
1 results could be compared with those obtained using neodyrahnn in the previous experiment4 MTE-3
2 Sd tracer used for following the rate of transfer of neodymiuni has a relatively short half-life (11 days) which would prevent excessive levels of radioshyactivity in the experimental equipment as additional neodymium containing 4 7 N d was added to the fuel salt during the expert-went
3 neodymium is one of the more important trivaknt rare-earth fission products to be removed from MSBR fuel salt
An attempt was made to start the first run (Nd-I )on June 91975 However a malfunction in the electronics of the speed control unit for the stripper-vessel agitator prevented startup After this unit was repaired run Nd-1 was started on June 15 1975 and the scheduled period of operation (100 hr) was completed on June 20 1975 Operating conditions of run Nd-I were 650 to 660CC (923 to 933degK) 5 rps agitator speeds in both contactor and stripper fluoride salt flow rate of 35 ccmin (58 X I 0 1 m 3sec) and LiCI flow rate of 12 litersmin (20 X IO 5 nrsec)
After 100 hr of fluoride salt and LiG salt circulation the fluoride salt circulation was stopped and the run was continued for 16 hr This was done to observe the expected large decrease in the concentration of neoshydymium in the smaller amount of fluoride salt in the contactor (102 kg) as compared with the 1072 kg contained in both the contactor and reservoir These data would provide a more accurate measure of the rate of transfer of neodymium across the fluoride salt-bismuth-thorium interface
Finally the circulation of LiG was also stopped The agitators in the contactor and stripper vessels were then operated for ^24 hr over a three-day period (8 hr each day) to allow the salt and bismuth phases to equilibrate in an attempt to determine neodymium distribution coefficients between the phases
3 L M Ferris Equilibrium Distribution of Actinide and Lanthanide Elements Between Molten Fluoride Salts and Liquid Bismuth Solutions Inorg Nucl Chem 32 2019 35 (1970)
4 Cfiem Ttchnol Dir Annu Prop Rep March 31 1973 ORNL-4883p 25
145
The experimental equipment operated safisfacturBy throaghout ran Nd- I AH operatiag variables were maia-taiaed at desired coaonioas Results obtained during run Nd-I are discussed in Sect 814
SI J Ran Nd-2
Run Nd-2 was done with the sam operating condishytions as ran Nd-I except for run deration (119 hr inshystead of 100 hrraquo Prior to run Nd-2 3590 mg of N d F
(250 tog of Ndgt coalaaaag 101 mCi of 4 7 N d tracer was added to the 97 kg of fad salt in the reservoir Including the ncodVaaum leinainaig in the furl salt at the end of ran Nd- I estimated to be 18 ppra ltwt) the neodymium concentration in the fuel salt in the resershyvoir at the start o f run Nd-2 is estimated to be 45 pom The neodynaum concentration in dte fuel salt in the contactor is estimated to be 9 ppm at the start of run Nd-2 We are uncertain of the amounts of neodymium in the other phases at the beginning of run Nd-2 as discussed in Sect 814
Run Nd-2 was started on July 13 1975 and was tershyminated on July 19 1975 after 139 hr of operation During the first 50 hr of operation the rate of transfer of neodymium into the lithium-bismuth phase in the stripper appeared to be about the same as observed during run Nd-I based en counting of the | 4 7 N d tracer in samples taken at regular intervals After about 60 hr of operation the transfer of neodymium into the bismuth-lithium phase in the stripper suddenly stopped and it was observed that neodymium was being exshytracted from the bismuth-lithium phase in the stripper into the LiCl in the stripper and contactor During the run a significant decrease in the emf between the stripshyper vessel and the contactor occurred (from ^160 mV to ^25 mV over a 30-hr period) indicating loss of lithshyium reductant from the bismuth-lithium phase The run was terminated after 139 hr of operation when it beshycame clear that useful information could no longer be obtained and it appeared that fluoride salt was being entrained into the LiCl in the contactor
814 Discussion of Results
Subsequent investigation and results of chemical analshyyses of samples of the salt and bismuth phases indicate that fluoride fuel salt was being entrained into the LiCl in the contactor throughout both runs Nd-I and Nd-2 Estimates of the amount entrained are shown below
Estimated amount of fluoride a l l transferred into LiCl Baas of estimate
Nd-I | I 0 laquo hr) Nd-I and -2 (Jul hr)
0292 kg Fluoride in IiO phase 0607 kg Thorium in B I - L I phase 0400 kg Increase in LKI level in
stripper
Based j a flaoriae analyses of 1X1 maple T taken daring nm Nd- I the enuaaaaeat of flaoride salt appears to have occurred at a relatively constant rate throaghoat the ran The total amount of neodyaaam which transshyferrer into the Li-K phase in the stripper daring ran Nd-I is estimated to be 300 mg The aaaoaat of aeo-dynaam contained in the entraiaed fad salt isestiuated to be 6 mg That most of the neodynaam which transshyferred into the Li-Hi in the stripper vessd was by mass transfer rather than as a result of eatiaauaeM
The reason for the ubstivtd enfaauaeat is not dear at present One explanation K that the 50-rps agitator speed is saffident to cause enirainment (entrainmeat of flaoride salt into the chloride salt occurred in the preshyvious experiment MTE-3 at 67 rps bat not at 5JO rps) Experiments are in piogiess for deternaaing whether this explanation is correct and results to date indicate that entranirmi does not occur at 3 3 rps Further experiments in MTE-3B w i l depend on determining the reason for the unexpected entrainment of fluoride nt into the LiCl- However it appears feasible to continue rare-earth mass transfer experiments in MTE-3B by removing the LiCI (contaminated with fluoride salt) and the Li-Bi solution from the stripper vessd after which purified LiCl and Li-Bi solution will be added to the system
The main nurpose of the metal transfer experiment is to measure mass transfer coefficients for the rare eanhs at the various salt-metal interfaces in the system and to determine whether a literature corrdation5 (based on studies with aqueous-organic systems) which relates many transfer coefficients to the agitator speed and other physical properties of the system is applicable to molten salt bismuth systems Data obtained from run Nd-I have been analyzed and estimates have been made of overall mass transfer coefficients for neodymium at the three salt-metal interfaces Even though entrainment of fluoride salt into LiO occurred during run Nd- I it is believed that the mass transfer rate for neodymium was not 5ignificantly affected The concentration of fluoride in the LiCl at the end of run Nd-I was vl_ wt 1 or 003 mole fraction Based on previous studies6 the disshytribution coefficient ) for neodymium between the molten bismuth-thorium solution and LiCl (mole fracshytion Nd in bismuthmole fraction Nd in LiCl) would be decreased by ^ 2 0 7 while the distribution coefficient for thorium would be decreased by a factor of ^150 This would result in a decrease in the separation factor
5 J B l-ewii Chan En Sri 3 24S 59 119541 6 I M Ferris el raquo Distribution of Lanthamde and
Actinide Klements Between Liquid Bismuth and Molten IKI-Iil- and liBr-lil Solutions Inorg ucl Chart 34 313 20(1972)
146
were t in
VIO to vIO1 i transferred
bull t o the Lid The ate of leaver of neodynuua across the three
byaaslysesofi the m Two analytical i
(1) coasting of the OS34acV by the 4 N i tracer aad (2)iKgttopicduu-
spectroaaetry luaed on ccejufhag of the 4 T N d tracer a aaMeriai buuare of the t w t j i i w of gt95 obtained at the end of run Nd-1 indicated that about 11 of the niudjununa mfrinaMj added to the fuel salt icaenvar had beea transferred iato the LMI irautioa at the stripper
The counting trchaiqf is a rapid method aad pro-oa the rate of transfer wide the mas llwwcui it does ant provide the
required for calculation of the overal mas transfer coefficients particalariy in the K-Th aad Lid
bull the contactor aad stripper vessels in which the less than 1 ppm
(wt) The isotonic ddutioa analysis is capable of accushyrately determining neodynmm conccntntioa down to -VOJOI ppmfwt) and resorts obtained from the isotopic duvtioo tednaque for the Bs-Th and LiCI phases were used for calculations of the overall mass transfer coeffishycients
Values for distribution coefficients for neodymium at the thru salt-metal internees were measured at the end of run Nd-1 for comparison with those calculated from the dau of Ferris3 bull (Table 82) The experimental values are in reasonable agreement with the calculated values in the absence of fluoride contamination indicashy
ting that the distrnVstsoa coefficieau for neodynnum were not seriously affected by the entKnuncnt of the fluorine sah into the chloride
Data obtained during run Nd-1 were analyzed by inuahawiiui solution of seven tune-dependent differenshytial mm rial twlanu equations (Fig 8 J ) that relate the
v i imdash F t laquo r V
raquo i W W F a laquos-X4gt
V j j l laquo bull Klaquoa (X-IVCraquo)-F(Xs-)^
V - MOLAR VOLUME OF EACH PHASE
F bull FLOW RATE MOLESSEC
7 L M Perm et d Distribution of Lanthannte and Actiniae Element Between Molten Uthium Halide Salts and Liquid Msmuth Solutions Inorg Piuci Oirm 342921 -33 lt1972)
OLOLDc RARE-EARTH DISTRIBUTION COEFFICIENTS MOLESMOLE
A AREA AT EACH INTERFACE CM
TaMrSJ Dutrwatioa coeffionrta for mod m msit iauat MTE-3B ran Nd-1
Salt-metal interface Calculated Experimental
Fluoride salt-Bi-Th LaO-Bi-Th LiQ-Li-Bi
0006 094
3-5 X 10
0013 064
gt I X I0raquo
Distribution coefficient laquo (mf Nd in bismuth)(mf Nd in salt) ^Conditions 6S0C (923degK) Li concentration in Bi-Th 40 ppm Li concentration in Li-Bi = 5 at no fluoride in LiG phase
K I KbdquoK gt RARE- EARTH OVERALL MASS TRANSFER COEFFICIENT CMSEC
X gt RARE- EARTH CONCENTRATION IN EACH PHASE MOLESCM
EQUATIONS USEO TO CALCULATE MASS TRANSFER COEFFICIENTS FOR METAL TRANSFER EXPERIMENT
MTE-3B
F raquo S X Equations awd to calculate maw traaafer coeffishycients for the metal Mifer p r a m experiment V volume of each phase x - rare-earth concentration l = lime A - mass transfer area F raquo flow rate D bull rare-earth distribution coeffishycient K = overall mass transfer coefficient
147
rate at which the rare earths r ~ transferred through the several stages to the distribution coefficients of the tare earth the mass flow rates and the mass transfer coeffishycients at each salt-metal interface The set of equations was solved using a computer program by selecting values for the mass transfer coefficients which resulted in the best agreement between the experimental data on rate of change of neodymium concentration in aB phases in the system and the calculated values Several trial-and-error iterations were required using adjusted values of mus transfer coefficients until a best-fit solution was obtained
The final calculated results for run Nd-1 are shown in Table 83 where the values for the overall mass tkjnsfer coefficients are given and are compared with values calshyculated by the correlation of Lewis5 The coefficients are lower than predicted and are similar to results obtained in the previous experiment MTE-34 Final analytical results for run Nd-2 are not yet available However for the first SO hr of operation the rate of accumulation of neodymium in the Li-Bi solution in the stripper appeared to be similar to that observed in run Nd-1 The significance of these absolute values of mass transfer coefficient cannot be assessed until the scaling laws in this type of contactor are known
8 L E McNeeje Engineering Development Studies )or Molten-Salt Breeder Reactor Processing o II ORNL-TM-3774 (in preparation)
8 2 SALT-MSMUTH CONTACTOR DEVELOTMENT
CH Brown Jr
Mechanically agitated nondispening salt-bismuth conshytactors are being considered for the protactinium removal step and the rare-earth removal step in the reference MSBR processing plant flowsheet These conshytactors have several advantages over packed-column salt-bismuth contactors
1 they can be operated under conditions that minimize entrainment of bismuth to the fuel salt returning to the reactor
2 they can be fabricated more economically from graphite and molybdenum components
3 they can handle more easily large flow-rate ratios of tismuth and molten salt
Experimental development of stirred interface contacshytors is being carried out in two different systems a facility in which molten fluoride salt is contacted with bismuth containing a dissolved reductant and a system in which mercury and an aqueous electrolyte phase are used to simulate bismuth and molten salt These two systems and the development work performed during this report period are described in Sects 821 and 822
Table 8J Oven mass transfer coeffkieM for iteodymmm m metal master experiment MTE-3B ran Nd-1
A (mmsec) A (mmsec) A (mmjecr
Measured1 Predicted value value ltlt)
Measured Predicted value value Cr)
Mease bdquod c Predicted value value i^)
00035 39 025 20 013 25
Based on the neodymium in the salt phase 1 I I
bmdash~ - mdash mdashmdashmdash at fluoride salt -Bi -Th interface
I D B
I l
at LiCl-Bi-Th interface
a LiO - Li-6i interface A j km k9Ds
= individual mass transfer coefficient fluoride sail to bismuth - individual man transfer coefftcien bismuth to Tuoride sail = individual man transfer coefficient bismuth In lithium chloride k - individual mass transfer coefficient lithium chloride to bismuth
where
DA - distribution coefficient between fluoride salt and bismuth Dg - distribution coefficient between chloride salt and bismuth Oc distribution coefficient between chloride salt and lithium-bismuth
cAgitator speed is 50 rps
MS
S 2 I Expernieafe win a fecsnmkaly Agitated Nnaaraquoprning Contactnr bull the Salt bull f a i t h
Flolaquortuumgt FariSty
Operation of a facility has continued in which mass transfer rates are being measured between molten LiF-BeF 2 ThF 4 (72-16-12 mok )and molten bismuth m a mechanically agitated nondispeising contactor The equipment consists of a graphite-lined stainless steel vessel salt and bismuth feed and receiver vessels and the contactor vessel h the first of these the salt and bismuth phases are stored between runs The other vessels allow for treatment of the phases with HF and H The comactor consists of a 6-ltn-diain carbon-steel vessel conta rang four I-in -wide vertical baffles The agitator consists of two 3-in-dhm stirrers having four noncanted blades A ^-in-dtam overflow at the intershyface allows removal of interfacial films i f present with the salt and metal effluent streams During a run the salt and bismuth phases are fed to the contactor by conshytrolled pressurization of the respective feed tanks the phases return to the receiver vessels by gravity flow A detailed description of the facility and operating proshycedures has been previously reported A total of nine mass transfer runs have been completed to date along with one hydrodynamic run intended to determine the amount of entrainment of one phase into the other at a sties of different agitator vxeds Results from the nine mass transfer runs have been previously reported ~ i
The experimental proceduie for and results obtained from the hydrodynamic run and treat men of the salt and bismuth with HF and H 2 are discussed in the reshymainder of this section
Experimental operation daring the hydrodynamic ran The hydrodynamic run was performed with salt and bismuth flow rates of M 5 0 and M 4 Q ccmin respectively The agitator was operated at three difshyferent speeds during the run 250310 and 386 rpm At 250 and 310 rpm three sets of unfdtereJ salt and bisshymuth samples from the contactor effluent streams were taken at 4-min intervals Three sets of unfiltered efshyfluent samples were aiso taken with the agitator operatshying at 386 rpm but the samples were taken at 2-min intervals
To avoid contamination of the sample contents with extraneous material the sample capsules were cleaned of foreign matter by the following procedure Gross amounts of salt or bismuth were first removed with a file then the sample capsule was polished with emery cloth and finally (he capsule was washed with acetone
The sample capsules were then cut open with a tubing cutter and the contents of each sample were drilled out
and visual)- inspected for the presence of one phase in the other Ho such evidence of gross entramment was found h some of the salt samples small flecks of metal were noticed which were probably small pieces of the sample capsule produced during the dnamg operation The contests of each sample were then sent to the Ana rytical Chemistry Division for dttuiiannion of brsrmnh present in gt salt samples and berynram present in the bismuth samples h is assumed that any berynmm present in the bismuth is mdkstive of entrained fluoride salt The results of these analyses are given in Table 84 The bismuth concentration in the salt samples shows a general decrease with increasing sarrer speed widi very low values occurring at the highest stirrer speed It also seems evident that the bismuth concentration in the salt phase may have been a function of the run time since after the fourth sample the bismuth concentration reshymained at a relatively constant value of 50 plusmn11 pom which is quite different from the values reported for the first four samples which ranged from 1800 to 155 ppm
These results are significantly higher than those of LindauerJ who saw less than 10 ppm of bismuth in
9 J A Klein el al tnaraquoeerme Development Stmmes far I M l d i U t Breeder Reactor hocesnm So bull ORNL-TS-463 Italy 1975) pp 2 3S
10 C H Brown Jr Engmttii-t Development Studies for Molten Salt Breeder Reactor rYoceomf So 21 ORNL-TM-4X94 (in preparation)
11 J A Kkai tnemeermw Drreiopmenl Studies of Molten-Smll Breeder Reactor Procenmt So IS ORNL-TM-469 (September 1974) pp I 22
12 C H Brown Jr Enjmerrmt Development Studies for Hoten Salt Breeder Reactor rVncezshu Vo 20 ORNL-TM-4810 (in preparation)
13 R B LindraeT fmjmeetmf Drreiopmenl Studies of Molten Salt Breeder Reactor Proceowtt So 17 ORNl-TM-41711 (m preparation)
TaWeS4 Kwmyraquoof ^aXmmhwmmmtn
Agitator speed Bi sample Be in Bi Sail sample Bi in salt (rpm) number (ppm) number (ppm)
250 42 215 437 100 250 429 125 43 205 250 430 215 439 155 310 431 85 440 270 310 432 910 441 53 10 433 442 34
36 434 110 443 64 36 435 175 444 54 36 436 50 445 43
149
fluoride salt in comact with b i t iu fh in several different contacting devices- It is likely that sample i nniiuuni tioa is a contributing factor to the high bcrmdashrh concenshytrations measured Three possible sources of sample coataaunaboa have been reported
I timtjuunitiou by withdrawing Imdashparr through a sample port which has been in contact wkh bismuth
analytical laboratory by the use of equipment roushytinely used for bismuth analyses
3 ctrwfuttiiuTmutftoit from bull hwy^CTWffy vt^tt^f^n^i^^^^UKttf material laquohkh may be floating on the salt surface
Since no maximum peiHUSMuk rate of bismuth eMram-ment in the fuel salt going to the bism ah removal step or m the salt returning to the reactor from the fuel processing plant has been set it is difficult to assess the significance of these results However the bismuth conshycentrations in the salt do not seem to be inordatttelv high at the highest stirrer speed and it seems Bkefy that some degree o f phase dispersal might be tolerated ia order to achieve higher mass transfer rates
The beryflium concentrations in the bismuth samples at each agitator speed show both high and low values with no discernaWe dependence on agitator speed These results agree well with previously reported data1 for beryllium concentration in the bismuth phase during mass transfer runs in this system at agitator speeds of 124 180 and 244 rpm Previous experiments with water-mercury and organic-mercury systems suggest entrainineni of the light phase into the heavy phase at an agitator speed of about 170 rpm The concentration of beryllium in the bismuth phase is not significantly different from previous results observed at lower agitashytor speeds The effect of entrsined fluoride salt in the bismuth would be most detrimental in the metal transshyfer process where fluoride salt in the chloride salt phase decreases the separation factors between thorn m and the rare-earth fission products
H -HF treatment of salt and bismuth The mass transshyfer runs completed to date in he salt-bismuth contactor have all been performed under conditions where the controlling resistance to mass transfer is in the inter-facial salt film One final mass transfer run will be pershyformed in which the bismuth-film mass transfer coeffishycient is measured In preparation for this run the salt and bismuth in the graphite-lined treatment vessel were treated with HF diluted with H 2 to oxidize the reduc-tants present in the bismuth phase The procedure used was essentially that reported previously14 The salt and bismuth at -v-oOOC were sparged with 25 scfh of 30 (mole) HF for 9 hr The HF utilization decreased from
7 5 at the 1 njiiiiini of treatment to 3 5 during the final 2 hr of treatmat Analysis of the ash and bismuth phases before and after treatment with HF and H 2 inshydicated that esaeatiaty a l of the rr duct ant in the bisshymuth phase was oxidized by hydrofluormatioa The mmtmm distribution ratio decreased from 740 molts mole prior to the treatment to OJ03 molemole after the HF-Hj treatment
L U ---r--8 iiiiiT I M I I I M M I U I I - j
We have continued development of a mrrhmii dlj agitated nondispersmg two-phase contactor wing an aqueous electrolyte and mercury to srmmatf mohea salts and bismuth
As previously reported1 we have investigated the feasibility of using a pobrographk technique for measuring electrolyte-film mass transfer coefficients in this type of contactor During this report period we have
1 tested three different anode materials 2 produced cathodk polarization waves corresponding
to the reduction of F e compkxed widi excess oxalate ions at the mercury surface
3 obtained and calibrated a slow-scan controDed-potential cyclic volumeter
4 examined the quinone-hydroquinone redox couple as a possible alternate to the F e -Fe couple now being used
Modifications to experimental equipment With the exshyception of the tests made with the qrinone-hydroquinone redox couple ail tests made during this pr ied were performed with the equipment previously described5
The equipment consists of the 5 X 7 in Plexiglas conshytactor used in previous work with the water-mercury system The mercury surface in the contactor acts as the cathode in the electrochemical cell The cathode is elecshytrically connected to the rest of the circuit by a Vg-in-diam stainless steel rod electrically insulated from the electrolyte phase by a Teflon sheath The anode of the cell is suspended in the aqueous electrolyte phase and consists of a metallic sheet formed to fit the inner perimeter of the Plexigas cell The current through the cell is inferred from the voltage drop across a 01 -SI plusmn 05 10-W precision resistor The signal produced
14 B A Hannaford (l jl Engineering Development Studies for HollenStll breeder Reactor Processing No 3 ORNL-TM-3l3ltMay 1971) p 30
15 C H Brown Jr Engineerin Development Studies for Mitten-Sit Breeder Reactor Processing So 22 ORNL-IM-4041 tin preparation)
ISO
on a on the
electrode
across the i Hevlen-Fackard xjr plotter The x nbtter bull nrodnoed hy the | the mncmy and a (SCE) suspended in the electrolyte |
to studies nun on the a stow-wcan controned-pocentieJ cyclic woks
patentNttat) was obtained fan the Analytical Chemistry Dtaunu to repfacr the Hewlett-Packard dc poawaapfiy iwtiionely wcd-ThecycJCfohnnrtrTiia three electrode mstrumeut which cortroh lraquo i bttnicn the mercury vnfuir and ai reference electrode whle paahag a cnrrent between the auxamry electrode and the mercury surface Voitafes can be itianrJ between tfVw SCE aad -2 Vw SCE ataacanrateaptol Vnnh The posentiostat can carry a carrot of up to 2 5 A between the auxSnry and mtiiury electrodes
npunninli ahh Ihi tt1 fi ililiai Thr rlrriin ryte used for al the experiments performed daring this report period was nouunaPy OJOOI M Ft2 obtained from ferrous sulfate 0X10025 M Fe obtained from ferric salfate and 0 J M potassium oxalate The oxalate ions form a stable complex with both the re and Fltr2
ftriuuif mnmumnm of the Fe1 reduction cdhccdy
Three anode nMcriab have been tested copper iron ml satisfactory polarization -aaves were pro-
I with al three materials However the copper and iron reacted with the electrolyte solution This addishytional uue reaction caned poor lewudacnwwty in the
I could aho p ornery alter the properties of the To amid tins cnobkrn an anode was fabrishy
cated by poring gold on a 0J062$-m-thka sheet of nickel which was formed to fit the inner perimeter of the electrochemical eel
Shown irgt Fig 8 J is a polarogram measured with the electrolyte described above in the 5 X 7 in Plexiglas contactor mag the gold anode with phase volumes of aboat IJ8 liters each and nc agitation The cell current it plotted as a function of the mercury sarface potential vs the SCE The cnrrent racreasts from zero at zero applied potential to a relatively constant value at an applied potential of about -035 V n SCE In this region contbtvons electrolysis is taking place in the cell corresponding to reduction of FetCiO^ 1 ~ at the mershycury cathode In the region of applied potential from -0J5 V vs SCE to -0JO V vs SCE the cell current
OMM 0W6 79- U429
1 1 1 1 1 1 1 S
2 lt
bull0t-M raquo raquo
m m m f~~ 5 u J I
J ew0^45V
ffl 1 1 1 1 1 0 -OJ -02
Fugt laquo3 Catholic bullohriarmi ware for FlaquoC O)
-0 5 -04 -OS VOLTM0C raquobull SCE
-OS -07 -oa
in Ac 5 X 7 J n m l raquo
151
increases only a smal iniaswt here the current is bullanted by ttugt rate of diffusion of the Fe(CzQlaquogtjgt~ to the mercury surface where this ion is rcdnced The difshyfusion current can be related to the nam transfer coefficient through the electrolyte fifan as prcwontly
The half-waw potential is defined at the potential at which the current is equal to one-half the hunting nine Figure 8 J shows the measured half-waw potential for the ferric oxalate coaapiex The half-wane potential of -0245 V measured in the contactor agrees weD with the wine reported in the literature of -024 V vs SCE for the reduction of ferric oxalate
Under ideal conditions the diffusion current is directly proportional to the polarized electrode surface area and the bulk concentration of the hinting km To detennine that the mercury surface was actually being polarized two tests were perfonned First the anode surface area was decreased by about 48 This had no effect on the magnitude of the diffusion current indishycating that the mercury surface (cathode) was polarized rather than the anode surface In the second test the concentration of the ferric ion was doubled but no concomitant increase in diffusion current was seen Since the diffusion current is directly proportional to the concentration of the limiting km (Fe1) the current should haw doubled The only explanation for this behavior is that the Fe had been reduced by some contaminant in the system possibly present in the mershycury This would have caused ferric ions to be present at only a wry low concentration during ceD operationdue to electrolytic oxidation of the ferrous iron
To ebminate the possibility of reductant being present in the mercury a supply of purified mercury was obshytained from the Analytical Chemistry Division A test was performed using the purified mercury and an elecshytrolyte having the same nominal Fe and Fe concenshytrations given abow Preparation of the electrolyte was completed in the absence of oxygen to preclude posshysible oxidation of Fe to Fe Again the anode surshyface area was decreased with no discernible decrease in the diffusion current indicating that the mercury surshyface was polarized An increase of the Fe concentrashytion from M)25 vnM to Mgt3 mW resulted in an inshycrease in the diffusion current by a factor of 2 indishycating that the waw being measured was the ferric ion reduction waw However the half-wave potential was measured to be -07S V vs SCE which is about three times the reported value
To calculate the aqueous-film mass transfer coeffishycient from poiarographic data the bulk concentration of the oxidized species must be accurately known The
n a n K amp j f a u f l l O u l a m m anuCntSnafsEafannTuB a m m nWanuWOnBTBsnnnnnT- ana^ne-w w ^ m w u^m w ^ p p ewajuajuaawmimaaaBmniw ma mi awnwaawgt^pwnnawBwanpap wa^anu
the electrolyte used in dm second of the two ter^jaen-tkmed abow woe analyzed for F e v asm F by this method Results hnhcatrd that the fie and Fe conshycentrations were 17 and 028 mMrespectiwry which is in poor agreement with the expected values of 030 ajtf Fe and 1J0 mmf Fe2 One poanok cause for the poor agreement is that the Ft 1 was oxidized to Fe during the period when the solution was held in the sample bottles However this was not expected since the dec-trotyta had been sparged with argon to remow dissolved oxygen and the sample botdes were purged with argon toremowair
To aid in oetennming if the reported analytical results were in error due to analytical technique or to method of solution preparation two standard solutions were prepared and sampled for analysis One solution was prepared to contain 56 ugim Fe and the other solushytion was prepared to contain 56 ugnd Fe1 Both solushytions were 1 WmKjCzO^HjO Subsequent analytical results indicated that both solutions had essentialy the same concentrations of Fe3 and Fe 1 50 and 27 fignil respectively Farther investigation wnl be necessary to determine the correct method for preparing andor analyzing iron oxalate solutions
Experiments with the qwmame-bydroonmmae system A possible alternate to the Fe -Fe system for measshyuring electrolyte-phase mass transfer coefficients is the reversible reduction of quinone to hydroquinone at the mercury cathode
The reaction under consideration is
C r l 4 0 + 2 H 4 + 2laquo-CHlaquo(OH) ( I )
Since hydrogen ion as wen as quinone is a reacting material a strong buffer must be present to serve as a supporting electrolyte The buffer causes the H conshycentration to be essentially constant across the inter-facial electrolyte film because the rate at which the buffer equilibrium is established is reiatiwfy rapid comshypared with the quinone diffusion rate1
A quaUtatiw test was made with the quinone system to determine whether acceptable polarization waves couM be measured and to determine whether the quishynone electrolyte is inert to mercury The electrolyte was 001 M hydroquinone and 0005 M quinone with a 0O5 M phosphate buffer at a pH of 70 Satisfactory polari-
16 i M Kolfhoff and 11 Latcanc p 44 inbfaromvp Intencfcnce New Yortt 146
I C A Lin el at Dirruson-Controiled Electrode Reacshytions Ind Eng Ckem 43 2136-43 (1951)
1S2
abon waves were obtained in a small cell with a large copper anode and a mercury pool cathode The electroshylyte was chemically inert to mercury during the tests The color of the quinone electrolyte changed from a light yellow to deep brown within several hours This phenomenon is due to the decomposition of quinone by ultraviolet light Further studies in the S X 7 in contacshytor will be done to determine whether tins system is suitable for mass transfer measurements
8 3 C0NTTNU0USFLU0IUNATOR DEVELOTMENT
R B Lindaucr
Continuous fluorinators arc used at two points in the reference flowsheet for MSBR processing The first of these is the primary fluorinator where 99 of the uranium is removed from the fuel salt prior to the reshymoval of 2 J J P a by reductive extraction The second point is where uranium produced by decay o f 2 Pa is removed from the secondary fluoride salt in the protacshytinium decay tank circuit These fluorinators will be protected from fluorine corrosion by frozen-salt layers formed on the internal surfaces of the fluorinator which are exposed to both fluorine and molten salt To keep frozen materia on the walls while maintaining a molten-salt core in the fluorinator an internal heat source is necessary to support the temperature gradient Heat from decay of the fission products in the salt will be used in the processing plant However to test frozen- JI fluorinators in nonradioactive systems
another internal heat source which is not attacked by fluorine is needed Since electrolytic or autoresistance heating of molten salt has proven to be a feasible means fx providing this heat source studies of auforesbtance ucating of molten salts are continuing A conceptual design was made for a continuous fluorinator experishymental facility (CFEF) to demonstrate fluorination in a vessel protected by a frozen-salt film Design was comshypleted and installation was begun of a fluorine disposal system in Building 7503 which uses a vertical spray tower and a recirculating KOH solution Installation was completed of equipment to demonstrate the effectiveshyness of a frozen-salt film as protection against fluorine corrosion in a molten salt system
8 J I autafetmi and Initial Operation of Aaloteststance Heating Test AHT-4
Equipment for autoresistance heating test AHT-4 was installed in ceil J of Building 4S0S fai this system (Fig 84) molten LiF-BeFj-ThF (72-16-12 mole 7r) is cirshyculated by means of an argon gas lift from a surge tank to a gas-liquid separator from which the salt flows by gravity through the autoresistance electrode through the test vessel and returns from the bottom of the test vessel to the surge tank The test vessel (Fig 85) used in experiment AHT-3 was decontaminated equipped with new cooling coils heaters and thermocouples and reinstalled for experiment AHT-4
The test vessel is made of 6-in sched-40 nickel pipe with a 44-in-)ong (II-m) cooled section from the elecshytrode to below the gas Inlet side arm The cooled secshytion is divided into five separate zones each with two
Oflm 0tJngt 79mdash4W5
bullbullOfF-CAS-
j M M N m laquo$urr|
SCMMTOft
JT~f
i II lraquo li II I I I I
Hi
HEAT FLOWMETER
AUTOMESISTANCC HCATIN6 POWER
SUff lV TEST
VESSEL
ARGON
Fig SA Ftowdwet for autoresifUncc heating test AHT-4
153
Ffc85 AHT-4 lest vewd
154
parallel coils through which an air-water mixture flows The gas outlet section above the salt level has an inshycreased diameter for gas-calt disengagement and is made of 8-io sched-40 pipe The surge tank has a 46-m4ong (I _2-m) 6-in-diam (01 S-m) section to provide submershygence for the gas lift The upper section of the surge tank is 24 in (0-61 m) in diameter and provides suffishycient capacity to contain the salt inventory for the enshytire system The gas-liquid separator is an 8-in-diam (O^Om) conical-bottom vessel with baffles and York mesh in the upper part for gas-liquid disengagement m the heat flowmeter the salt is heated by an internal cartridge heater and the flow rate is calculated from the heat input and ihe temperature iise of the uit stream
The system is started up by heating the equipment and Hnes to 600C (873degK) The argon gas lift is started and initially the salt flow rate is determined by the decrease in surge-tank liquid level After the salt levels in the tank separator and test vessel are constant cooling of the test vessel is started The resistance beshytween the high-voltage electrode and the test vessel walls is checked periodically by applying a low voltage
to the electrode and measuring the current As cooling progresses this resistance wul increase until the point is reached where heat can be produced in the salt at a significant rate (several hundred watts) without cauang a reduction (shorting) of the resistance
The 80-liter salt batch was charged to the surge tank and after minor modifications to the heating system operation was started Four preliminary runs were made lasting from 4 to 12 hr (from the time the gas lift was started until plugging occurred) In the first run plugging apparently occurred in the electrode when the liquid level in the separator fefl too low to provide sufshyficient head for flow to the test vessel
Salt flow in the second run was much smoother and circulation continued for 11 hr without adjustment of the gas lift During this time the test vessel was being cooled and the salt flow rate slowly decreased by V7 from 450 to 425 cnvVmin This was probably caused by an increase in salt viscosity a buildup of frozen salt in the test vessel or a combination of the two The steady salt flow rate and higher salt temperature fgt873 0K and 20-3TK higher than in run No 1) kept the electrode from freezing but the heat supply at the bottom of the test vessel was insufficient to keep the salt outlet from freezing which terminated run 2 The resistance beshytween the high-voltage electrode and the vessel waO increased from 001 to 0X1812 but autoresistance heatshying was not attempted The vertical portion of the test
section had been cooled to 639degK (sobdus temperature 623degK)
Before the third run the output of the powerstat conshytrolling the test vessel bottom heaters was increased by 44 to keep the salt outlet above the freezing point The ran was terminated by salt freezing in the elecshytrode This resulted from too low a salt flow rale (the heat flowmeter was inoperative because of a burned out heater) and too low an initial temperature (723degK vs 823degK in the second run) in the vertical section of the side arm through which the electrode passes
The fourth run was started with some heat on the vertical section of the side arm This section was unshyhealed prenocty As coohng progressed the bottom heaters on the test vessel were inadequate at the salt flow rate being used Increasing the salt flow rate preshyvented freezing at the bottom of the test vessel After 754 hr of operation the liquid levels in the separator and test vessel started to increase indicating salt flow probshylems both at the inlet and exit of the test vessel Alshythough the salt resistance had only increased from OX) I to 003 ft and the average test vessel wall temperature (in the cooled zone) was 658degK autoresistance heating was suited This freed the plug in the electrode allowshying salt flow from the separator to the test vessel and the increased flow raised the test vessel bottom tempershyature and flow resumed from the test vessel However salt flow rates were erratic for the next 2 hrand 9K hr after the start of the run the tert vessel level started to rise indicating a frozen salt restriction in the vessel It was decided to try to transfer the molten salt from the test vessel to the surge tank before complete plugging occurred This was done successfully and 56 liters of salt was transferred to the surge tank After cooling radiographs were taken of the test vessel by the Inspecshytion Engineering Department using a 35-Ci J l r source In the test section of the test vessel radiation penetration was insufficient to permit measurement of the film thickness The bottom of the vessel between the salt outlet and the gas inlet was free of salt as exshypected and the radiograph of flu top of the vessel showed a 25-mm-thick ring of salt above the normal liquid level This is salt deposited on the colder pipe wall by the action of the gas bubbling through the salt Calculations from the volume of salt transferred indishycated an average film thickness of 45 mm (a 65-mm-diam molten core) The salt resistance at the end of the run was 018 ft and the maximum autoresistance heatshying used was 450 W
The main problem seems to be the forming of a unishyform salt film Near the electrode where the hot molten
155
salt enters cooling is much slower than in the vertical section above the gas inlet It is probably in the vertical section where the salt flm becomes too thick and reshystricts the salt flow
8J2 o f Facaty(CFEF)
The purpose of the CFEF is to measure the perforshymance of a continuous fluorinator which has frozea-wali corrosion protection in terms of uranium removal The uranium which is not volatilized but is oxidized to UFs wfll be reduced back to UFlaquo in a hydrogen reducshytion column The facility wul be used to obtain operatshying experience and process data including fluorine utilishyzation reaction rate and flow-fate effects and to demonstrate protection igainst corrosion using a frozen salt Aim
The facility will be installed in a ceD in Buflding 7503 to provide beryllium containment The system wfll conshytain about 8 ft 3 (023 m J ) of MSBR fuel carrier salt (72-I6-I2 mole 3 LiF BeF -ThF4) containing OJS mole ltpound uranium initially The salt wiD be circulated through the system at rates up to 50 of MSBR flow rate (67 X I 0 m 3xc) Because of the short fluorishynator height (1 to 2 m) the amount of uranium volatilshyized will be between pound0 and 95 per pass The variables
of salt flow rate fluorine flow rate and fluorine conshycentration wil be studied by measuring the UFlaquo conshycentration in the fluorinator off-fas stream and by sam-pKrg the salt stream after reduction of UF to UF 4 The fluorinator laquo 4 have two fluorine inlets to provide data for determining the column end effects Reduction of UF 5 war be carried out in a gas lift in which hydroshygen will be used as the driving gu and also as die reduc-tant If additional reduction B required tins can be done in the salt surge tank The surge tank is designed to provide sufficient salt inventory for about 10 hr of fluorination with 95$ uranium volarihntion per pass About 99 of the uranium should have been removed from the salt batch after this period of time
The faculty flowsheet is shown in Fig 86 Salt wil enter the fluorinator through the electrode m a side arm out of the fluorine path The electrode flange wil be insulated from the rest of the fluorinator and the auto-resistance power wiD be connected to a lug on the flange The salt wfll leave at the bottom of the fluorishynator below the fluorine inlet side arm The fluorinator wall wiD be cooled by external air-water cons to form the frozen salt film which wfll serve the dual purpose of preventing nickel corrosion and of providing an electrishycally insulating film for the autorcsistance current Below the fluorine inlet the fluorinator waB will not be cooled and the molten salt wul complete the electrical
TO FLuomnc ftSPOSM STSTU
JVTO-K S S T M C C ~ T M M
TCU f
ifSEMMUl
r-Gf=imdashlaquobullmdash^ni
TOorr-cts
^ - bull I I I T Z
FMCZC VMVC
MPWCTNM COLUMN
CAS-LIFT
HVOMMCR
rO F K M I VMVI
Fit HA Conf immu flaottnalor experimental facility flow Acer
156
OfML DWG 75-15057
FLUOMNE-CONTMHNG U S
TO N 0 T OFF-GAS SYSTEM
Fjs87 Ftmnmt4mfpmtwfmtm
nrcuit to the vessel wall Since all of the uranium will not be volatilized from the salt there will be some UF 5
in the salt at the bottom of the fluorinator The luori-nator bottom exit line and reductio- column will be protected from the highly corrosive UF 5 by gold lining or plating The molten salt containing UF S will enter the bottom of the column where the salt wit be conshytacted with hydrogen The hydrogen will enter through a palladium tube which will result in the formation of atomic hydrogen and greatly increase the reduction rate to UF 4 The hydrogen reduction column will also act as a gas lift to raise the salt to i gas-liquid separator The salt will then flow by gravity to the fluorinator through a salt sampler surge tank heat flowmeter and electrical circuit-breaking pot Off-gas from the separator which contains HF and excess hydrogen will pass through an NaF bed for removal of the HF Uranium ixxafluoride from the fluorinator will also be removed by NaF Mass flowmeters before and after the NaF beds will be used to continuously measure the UFA flow rate
83J Fluorine Disposal System for Building 7503
The CFEF (Sect 832) will be the first test of the frozen-wall fluorinator using fluorine For the disposal of the excess fluorine a vertical scrubber is being inshy
stalled in Building 7503 A flow diagram of the system is shown in Fig 87 The scrubber is a o-in-diam 8-ft-bJgh (015- by 24-m) Mond pipe with three spray nozzles in the upper half of the vessel The surge lank contains 200 gal (09S m) of an aqueous solution conshytaining 15 wt KOH and 5 wt Kl This equipment is designed to be able to dispose of one trailer of fluorine (18 std m 3 ) at a flow rate of 12 scfm (9 X 10 std msec) The KOH solution wil be circulated through the spray nozzles at a total flow rate of 15 gpm (OJOOI msec) The fluorinator off-gas stream will flow cocur-rently with tnis stream The scrubber exit stream passes through a photometric analyzer for monitoring the efficiency of the scrubber
8J4 Frozen-Wafl Corrosion Protection Denomtration
Equipment has been installed for demonstrating that a frozen salt film will protect a nickel vessel against fluoshyrine corrosion ty preventing the NiFj corrosion prodshyuct film from being dissolved in the molten salt A small vessel containing 6 X I 0 1 m 1 of molten LiF-BeFj-ThF4 (72-W 12 mole ) will be used for the demonshystration (Fig 88) The fluorine inlet consists o hree concentric tubes which provide a path for an air coolant
157
FLUOraquoK IN
JL
SALT IXVCL-
OuT
- raquo F L laquo O M OUT
FlaquoSJ Ffi
stream that will be used for freezing a salt film on the outside of the outer tube The wall of the inner lube through which the fluorine will flow is 31 nils (079 mm) thick The inner lube of the fluorine inlet will not be protected from corrosion The vessel wall is also unprotected but is 280 mils (711 mm) thick Fluorine will be passed at a low flow rate (-v830 mmsec) through the salt until failure occurs which is expected in less than 100 hr at the tip of the probe near the gas-liquid-foiid interface Wall thickness measurements before and after the demonstration will show to what extent the salt film afforded protection
A flow diagram for the system is shown in Fig 89 The argon back pressure will be recorded to provide an ndication of corrosive failure Failure of the tube below
the salt film will allow some salt to leak into the argon cooling annulus The salt will be entrained up into the cool portion of annular space causing a restriction to
the argon flow The system waf be designed such that the fluorine flow is terminated automaticaly when either a low argon pressure is detected in the anrndus or when a high argon back pressure occurs
84 FUiaiWCONSnTUnON ENCINEEJUNC OEVELOTMENT
llMCounce
The reference flowsheet for processing the fuel salt from an MSBR is based upon removal of uranium by fluorinatioa to UFraquo as the first processing step 1 The uranium removed in this step must subsequently braquo reshyturned to the fuel carrier sal before i u return to the reactor The method for recombiniag the uranium with the fuel carrier salt (reconstituting the fuel salt) consists in absorbing gaseous UFraquo into a recycled fuel salt stream containing dissolved U F 4 affording to the reacshytion
UF f c(g)UF4ld) = 2UF(draquo laquo2raquo
The resultant UF S would be reduced to U F 4 with hydrogen in a separate vessel according to the reaction
U F ltdgt bull H (ggt = UFlaquo(d) bull HF(ggt (31
Engineering studies of the fuel reconstitution step are being started to provide the technology necessary for
the design of larger equipment for recomputing UFraquo generated in fluorinators in the processing plant with the processed fuel carrier salt returning to the reactor During this report period equipment previously deshyscribed was fabricated and has been installed in the high-bay area of Building 7503 This report describes instrumentation for off-gas analysis including a prelimishynary calibration curve and two alternatives for proshyviding corrosion-resistani gold linings for equipment to be installed later
The nickel reaction vessels presently installed will be used to test the salt metering devices and gas supply systems After the initial shakedown work is completed the UFraquo absorption vessel Hj reduction column flowing-stream samplers and associated transfer lines will be replaced with gold or gold-lined equipment Gold is being used because of i u resistance to corrosion by UFraquo gas and U F dissolve in the salt
1972 18 Chem Technol Dh Anim frogr Kept Mar SI ORNL-4794p I
19 R M (ounce Engineering Development Studies for MolenStll Breeder Reactor Processing So 19 ORNL-TM-4863 (July 1975) pp 38 42
158
OMN M 6 rS-OTM
FCV-3 nOccWM HASTMGS MASS FLOWMETER
ACTIVATED ALUMNA TRAP
Ffeft9 FfocM ait BtotaciiMi
841 for Analyzing Vest Off-Goes
The equipment for the second phase of the experishyment will consist of a feed tank a UF absorption vesshysel an Hj reduction column flowing-stream samplers a receivei tank NaF traps for collecting excess UF and for disposing of HF gas supplies for argon hydrogen nitrogen and UFraquo and means for analyzing the gas streams from the reaction vessels (Fig 810) The equipshyment wul be operated by pressurizing the feed tank with argon in order to displace salt from the feed tank to the UFlaquo absorption vessel From the UFlaquo absorption vessel the salt flows by gravity through a flowing-stream sampler into the H2 reduction column From the Hj reduction column the salt flows by gravity through a flowing-stream sampler to the receiver tank Absorption of gaseous UF t by reaction with dissolved UF 4 wiD occur in the IFF absorption vessel and the resultant UF5 will be reduced by hydrogen in the Hi reduction column The effluent salt is collected in the receiver tank for return to the feed tank at the end of the run
The off-gas from the absorption vessel and the reducshytion column will be analyzed for UF and for HF reshyspectively
The respective off-gas streams will be continuously analyzed with the use of the Cow-Mac gas density balance A sample stream is taken from the main off-gas stream and passed through the balance for analysis (Fig 811) These analyses wiO be used in determining the efficiencies of UF absorption and H 2 utilization
The efficiency of UF absorption will be determined by metering UF and Ax to the UF reaction vessel and determining the UF content in the vessel off-gas using a model 11-373 Cow-Mac gas density cell2 The H utilization will be determined similarly Hydrogen will be metered to the H 2 reduction column and the column off-gas wD be anayzed for Hj content also using a model 11-373 Cow-Mac gas density ceD The Cow-Mac cell commonly used as a gas chromatograph
20 Gow-Mac Instrument Company 100 King Road Madison New Jersey
159
bullWLDIN6
bull SYSTEM
Flaquo SIO Ftow lt ^ w o gt n ^ w i l M
msw NEACnON VflaquoSCL
P9E Y
f OWL DUG 7VS909
0FF-6AS
j r _^DT
KOC
ROTCTER|V] $
Ffc 811 SdMMMtic M of fMl ncomtitalfcM experiment off-gn
160
detector provides a continuous signal which varies directly with the density of the sample gas allowing continuous analysis of the sample gas stream with accushyracies of 3 to 4ft Because the detector elements are not exposed to the sample stream the gas density cell is useful in analyzing corrosive gas mixtures
Nitrogen and argon will be reference gases for the gas density cells used for analyzing the off-gas from the UF absorption vessel and the H reduction column respectively The response of the gas density cell is fairly insensitive to changes in the sample gas flow rate when nitrogen or argon is used as a reference gas2 z To measure varying Ar-UF and H2-HF ratios with the gas density detectors it is necessary to control the refershyence gas flow rate precisely However Irigh precision is not required for controlling the sampie g^ flow rate The reference gas flow rates are controlled sufficiently by rotameter and separate gas supply systems A satisshyfactory means for providing reproducible sample flow rates has been developed The sample stream is taken from the main off-gas stream (Fig 811) and flows through a capillary tube the gas densiiy detector an NaF trap to remove the corrosive constituent (UF or HF) and a bubbler to provide a constant downstream pressure The pressure upstream from the capillary is maintained at a higher constant value by means of a similar bubbler in the off-gas line downstream from the NaF trap The NaF traps provide sufficient volume in the lines so that small pressure fluctuations from bubshybles in the process vessels and in the bubblers are effecshytively damped out The flow rate is not constant (although it is reproducible) because as the concentrashytion of the sample gas changes its viscosity changes producing changes in sample flow rate under the prevailshying conditions These flow rate changes superimposed upon concentration changes in the sample stream to the gas density detector result in a nonlinear response of the gas density detector to changes in concentration The effects are reproducible however and a reproducible calibration can be obtained Such a calibration was obtained with mixtures of hydrogen and nitrogen (Fig 812)
For sample gases containing hydrogen and at refershyence gas flow rates below a certain critical flow rate hydrogen will diffuse countercurrently into the refershyence gas stream to the area of the detector elements
21 J T Wjfoh and D M Roue tor Oiromalofr US) 232 40 17)
22 C L Ouillemm and M K Auricourf (its Chromalogr I 24 29 (October 1963)
onw MG re-mo
i i i 1 bull mdash I I I I i DO 90 0
2
Ffc 812 Cafeoraam i laquo of Gow-Mac gas Oettmtf ccM MOM in fad iccoasMatioa t^mtimj claquojlaquoipmlaquoi for H ami N-
Due to the high thermal conductivity vf H the back diffusion of H can greatly affect the sensitivity of the gas density cell However if sufficiently high reference flow rates are maintained this problem can be overshycome
842 Design of the Second Fuel Reconftitutkm EjtgMecimg Experiment
The design of equipmeni for the second fuel reconsti-lution engineering experiment (FREE-2) is continuing The equipmeni for FREE-2 will be similar in design to the equipment for experiment FREE-I except for the addition of an intermediate liquid-phase sample port beshytween the UFraquo absorption vessel and the H 2 reduction column (Fig 810) In addition all vessels and transfer lines exposed to dissolved UF 5 with the possible excepshytion of the receiver lank will be gold or gold lined Gold sheet 0010 if (02S mm) thick is on hand for the fabricated liner of the UF absorption vessel Two altershynative exist for lining the H 2 reduction column and the receiver vessel interior gold plating or a fabricated gold liner
The minimum plating thickness that would probably provide a pinhole-free liniig is approximately 0005 in (013 mm) The minimum thickness for a fabricated gold liner in vessels of this size is approximately 0010
161
in (025 mm) Fabricated gold liners are economically competitive with gold plating in the thicknesses menshytioned because gold sheet is available at ERDA prccious-mctal account prices approximately S3499troy oz (SII3g) and gold in commercial gold-plating solutions is available only at market prices of about Sl64troy oz (S5J7g) as of June 18 1975 Some comparisons important in the choice between interior gold plating or fabrication of a gold liner are
1 the technology involved in fabricating a welded gold vessel is available while some technology would need to be developed for interior plating of vessels having a high lengthdiameter ratio such as the H2
reduction column 2 the time involved in both approaches is approxishy
mately the same 3 the plating will be difficult to inspect and there will
be no guarantee of pinhok-free coverage while dye penetrant examination of welded joints is available for a fabricated liner
Because it is unclear whether there is sufficient gold in the ERDA precious-metals account for lining the reshyceive tank liner gold plating is favored There is the ziditional alternative bullbull not lining the receiver tank since i orrosion of the receiver vessel by UF5 in the salt could ie tolerated and corrosion products could be reshymoved by hydrogen reduction and filtration between runs
85 CONCEPTUAL DESIGN OF A MOLTEN-SALT BREEDER REACTOR FUEL PROCESSING
ENGINEERING CENTER
D I Gray J R Hightower Jr
A conceptual design is being prepared to define the scope estimated final design and construction costs method of accomplishment and schedules for a proshyposed MSBR Fuel Processing Engineering Center (FPEC) The proposed building will provide space for the preparation and purification of fluoride sail mixshytures required by the Molten-Salt Reactor Programfor intermediate- and large-scale engineering experiments associated with the development of components reshyquired for the continuous processing capability for an MSBR and for laboratories maintenance work areas and offices for the research and development personnel assigned to the FPEC
bullORNI Knpneeriti Division
The project wSI consist of a nev three-story engineershying development center approximately 156 ft (475 m) wide by 172 ft (524 m) long The building will have a gross floor area and volume of 54300 ft 2 (5100 m x ) and 1218J0O0 ft J (34300 m J ) respectively and vhB be constructed of reinforced concrete structural sled concrete Mock masonry and insulated metal paneling The building will be sealed and will be operated at negashytive pressures of up to 0 J in of HjO (75 Pa) to provide containment of toxic materials The FPEC wit be located in the 7900 area approximately 300 ft (91 m) west-southwest of the High Flux Isotope Reactor The engineering center will contain
1 Seven multipurpose laboratories buu on a 24 X 24 ft (7 J X 7 3 m) module for laboratory-scale experishyments requiring glove boxes and walk-in hoods
2 A high-bay area 84 X 126 ft (256 X 384 m) equipped with a 10-ton (9000-kg) crane for large-scale development of processes and equipment for fuel processing at the pilot-plant level
3 A facility for preparing and purifying 16000 kg per ye-r of fluoride salt mixtures needed for the Molten-Salt Reactor Program
4 Support facilities including counting room process control rooms change rooms lunch and conference room and data processing room
5 Fabrication and repair shop decontamination room and clean storage areas
6 A truck air lock to prevent excessive ingress of outshyside air during movement of large equipment items into and out of the high-bay area
7 Two 5-ton (4500-kg) service elevators one inside the building to service the regulated areas and one outshyside to service the clean areas and to move filters to filter housings on the third floor and roof
8 General service and building auxiliaries including special gas distribution systems liquid and solid waste collection and disposal and filtered air-handling and off-gas scrubbing facilities
The experimental program planned for the building involves large engineering experiments that use 2 1 U 2 T h Be hazardous gases i F a H 2 and HF) molten bismuth and various fluoride and chloride salts Inishytially radioactivity will be limited to that necessary for low-level beta-gamma tracer experiments The laborashytory area can later be upgraded if desired for use with alpha-emitting materials at levels up to I kg of n P u
The laboratory area will consist of seven 24 X 24 ft (73 X 73 m) modular-type laboratories and a general-purpose room Bench-scale experiments of the type now performed in buildings 4505 3592 and 3541 will be
162
carried out m these laboratories FtoMems encountered in the large-scale experiments can be studied via smaE subsystems Inert-atmosphere glove boxes wil provide space for examination of samples removed from both the large and the small experiments The laboratory area wul be maintained at a negative pressure of 0 J m of H 2 0(75Pa)
The high-bay area wul be the main experimental area where large engineering experiments wifl be performed Experiments wnl involve circulating mohen mixtures of LiF-neFj-ThF4 lithium chloride and molten Bi-Li alloys The experiments wffl also use elemental fluorine hydrogen fluoride hydrogen chloride and hydrogen gases as reactants and wnl use purified argon for purgshying Excess fluorine hydrogen fluoride and hydrogen chloride wil be neutralized in a caustic scrubber using KOH solutions and the cleaned and filtered off-gas win be ducted to a bunding exhaust system The experishymental equipment and components wil be housed in steel cubicles with floor pans which can contain any salt spJO The cumdes wnl be maintained at a negative presshysure with respect to the high-bay ambient The high-bay area can be supplied with up to 45000 cfm (212 msec) of air The air can be from recirculated inside
air laquo fresh ak from the outside The high-bay exhaust system wil be designed for 30jOOOcfm ( I 4 J msec)at floor level and 50000 cfn (236 msec) at the roof framing level A l exhaust ducts wnl contain fire barriers upstream from the double HEP A filter banks
The salt preparation and purification area wil consist of a 25-ft-wide by 3S-ft4ong by 14-ft-hJgh (76 X 107 X 4J m) raw materials storage room a 22 X 22 X 28-ft-high (67 X 67 X 8J m) room for weighing and blending the salt constituents and a 40-ft-wide by 45-ft-loug by 28-ft-high (122 X 137 X 85 m) room for melting rk-HF treating and filtering the fluoride salt mixtures This facility should be capable of producing I6j000 kg per year of fluoride salt mixtures using the batch processing method in use at the (acuity at Y-12
The estimated cost for the FPEC is SI 5000000 of which $5200000 provides for inflation during the three years required for design and construction of the baking
The design is essentially complete and the conceptual design report is scheduled to be issued in September 1975 Authorization for this project will be proposed for FY 1978
Part 5 Salt Production
9- Production of Fluoride Sak Mixtures I
F L Daley
A salt production facility is operated by the Fluoride Salt Production Group for preparation of salt mixtures required by experimenters in the MSR Program The group is responsible for blending purifying and packshyaging salt of the required compositions
Much of the salt produced is used in studies on Hast el -loy N development in which the concentrations of metal fluorides particularly nickelironand chromium are important study parameters Ic is thus desirable to use salt in which the concentrations of these metal fluorides are low and also reproducible from one salt batch to the next Oxides are undesirable salt contamishynants primarily because of the adverse effect of uranium precipitation and also because of the effect of oxides on corrosion behavior of the salt Sulfur is another conshytaminant present in the raw materials used for preparing salt mixtures Sulfur is quite destructive to nickel-based alloys at temperatures above 350degC because a nckel -nickel sulfide eutectic which melts at about 645degC penetrates the grain boundaries and leads tc inlergrlaquonu-lar attack of the metal The maximum desired ievels for these contaminants in the fluoride salt mixtures are iron 50 ppm chromium 25 ppm nickel 20 ppmsulshyfur lt5 ppm oxygen lt30 ppm Other duties of the group include procurement of raw materials construcshytion and installation of processing equipment and reshyfinement of process operating methods based on results from operation of the production facility
When the facility was reactivated during 1974 initial production was carried out in existing small-scale (8-in-
bullConMiliam
r MSR Program Research and Development
RWttorton
diam) reactors while new large-scale (I2-in-diam) reacshytors were eing installed Experience with both the small and laige units is summarized in the remainder of this chapter
91 QUANTITIES OF SALT PRODUCED
The 3-in-diam reactor was used for production from startup of the program in early 1974 through the first three months of 1975 During this period a total of nine full-scale batches (315 kg total) were processed and made available to investigators Salt from the nine batches was shipped in a total of 2i containers of apshypropriate sizes In general operation of the 8-in-diam reactor proceeded smoothly and the resulting salt was of acceptable composition and purity
Production in the 12-in-diam reactor was started in March 1975 Five production runs each involving about 150 kg of salt have been carried out Of the five salt batches processed four were suitable for use most of the salt from these four runs was used for fuel procshyessing experiments In contrast to the earlier runs in the 8-in -diam reactor difficulty has been observed in the 12-in-diam reactor with corrosion of dip lines in the meltdown vessel and with increasing concentrations of metallic impurities in the product salt
92 OPERATING EXPERIENCE IN l2-in-diani REACTOR
Operating data from the five production runs in the 12-in reactor are summarized in Table 91 Analyses of the resulting salt batches are given in Table 92 A description of the processing operations and conditions
164
TaMe9l ttoccMag fab derived fto to rave taae ami titntioa of iafci aad oatlet flows
Batch number (FS-)
Batch size
ltkgt
Total tarn Ihr)
HF in
(moles) in
(motes)
HF out
(molest
HF reacted (moles)
Dariag hydmlhoriaatiMi 101 150 125 1953 4253 1712 241 102 150 1025 2331 2738 2331 0 103 150 975 1808 2603 1419 389 104 150 95 2853 2473 2434 399 105 12 140 3752 2857 1877 1876
Batch number |FS-)
Batch size
Total time
Total H in
Total HF out
HF in otT-jraquos Imeq per liter of H) Batch
number |FS-) Ike) (hr) (moles) (moles) Start Finish
Daring hydrogen ledacliua
101 150 176 4725 0026 00018 00064 102 150 186 4995 0595 0100 0O50 103 150 244 6520 1560 0625 0016 104 150 440 12040 2180 0746 0008 105 112 320 8514 3290 0476 0102
Table 92 Aaatyxsof 1501 batches of LiF-BeF -ThF4 (72-16-12 mole )
prodaced in die 12-araquo learior
Batch number (FS-)
Analyses Batch
number (FS-) Li r)
Be Th F rlt)
Fe (ppni)
Cr (ppml
Ni (ppml
S (ppnw
O (ppm)
Nominal 72-1612 790 228 4411 4571
101 795 252 4392 4620 82 24 17 737 lt25 102 8 64 222 4200 4600 75 30 600 80 360 103 811 231 4327 4574 60 25 8 25 350 104 839 200 4381 4532 85 65 10 91 NO 105 1046 290 3435 5125 82r 25 8 576
prevailing during hydrofluorination and hydrogen reduction is given in the remainder of this section
921 Charging and Metting of Raw Materials
The salt produced in the l2-laquoi-diam reactor has been of the MSBR fuel carrier salt compostion (72-16-12 mcle LiF-BeFj-ThF4) production of salt of this composition will continue except that some batches will also contain 03 mole UF 4 If the production schedule permits an inventory of non-uranium-bearing salt will be accumulated before beginning the producshytion of uranium-bearing salt The LiF raw material for
the salt production facility is supplied by Y-12 as needed the BeF2 and ThF 4 are taken from raw mateshyrials that have been on hand for several years The only apparent effect of the long storage time on the raw materials is an increased moisture content of the BeF2
The production unit includes two l2-in-diam 72-in-high type 304 stainless steel vessels each of which is (Wed internally with a full-length open-top copper cylinder in which the salt is contained One vessel is used for batch melting of the raw material) which are charged to the meltdown vessel by gravity transfer through a 2-in-diam pipe the pipe extends into a weighing and charging room and is closed by a sealing
165
flange except during the loading operation The second unit the processing vessel is identical to the meltdown vessel except for the charging line Both vessels are fitted with dip lines for introducing gas to the bottom of the vessels for mixing or purifying a salt batch and both are connected to an off-gas system Each vessel is supported in a stainless steel liner and while in use is located in a heavy-duty electrical furnace The receiver vessel to which the salt product is transferred is 12 in in diameter 36 in high and is supported similarly in a furnace adjacent to the processing vessel furnace Salt transfer lines from the meltdown vessel to the procshyessing vessel and from the processing vessel to the reshyceiver are autoresistance heated via a 24-V power supply
The operational sequence includes salt charging meltshying and mixing in the meltdown vessel and transfer of the resulting salt to the processing vessel for purificashytion The process steps include hydrofluorirution hydrogen reduction and filtration during transfer of the purified salt from the processing vessel to the receiver vessel During both the hydrofluorination and hydrogen reduction steps the receiver and processing vessels are maintained at the same temperature and the process gases are passed through the receiver before being fed to the processing vessel in order to eliminate any oxide film on the interior of the receiver
The raw materials are loaded into the meltdown vessel by technicians wearing air suits having a supply of cooled fresh air The work is carried out in a small enclosed room in which containment is maintained by positive flow of air through the room to a bank of absolute filters The appropriate quantities of each of the raw materials are weighed and charged through a loading chute directly into the l2-in-diam melidown vessel which is at room temperature The larger lumps of BeF 2 and occasional lumps of LiF are broken by hand to facilitate loading and to provide improved mixshy
ing The ThF 4 is a fine powder which does not require six reduction The charging method leaves much to be desired melting would be more rapid and more predictshyable i f the particle size of the raw materials could be reduced and all components mixed well before they are charged to the meltdown vessel
Some of the more important impurities in the raw materials are listed in Table 9 3 The values shown are average values in most cases The metallic impurities are satisfactorily low however sulfur and possible silicon contribute to corrosion problems during melting of the raw matercls The moisture content of the raw mateshyrials is not shown but is an important parameter It is believed that hydrolysis of the fluorides during the initial heating period generates hydrofluoric add which subsequently reacts with sulfur- and silicon-containing compounds in the raw materials to form hydrogen sulshyfide and fluoroalidc add The quantities of these mateshyrials produced appear to be dependent on the temperashyture at which the meltdown vessel is held during the initial portion of the melting operation with 2 S proshyduction being most noticeable at temperatures above S00degC An addic compound which contains silicon and fluorine is evolved freely at lower temperatures in the 125 to 500degC range however the extent to which the material is corrosive to the meltdown vessel is not known Analytical data necessary to determine whether these low-temperature gases contain sulfur-bearing comshypounds are not available
The major effect of hydrogen sulfide on nickel comshyponents at temperatures in the rage 600 to 700degC is rapid eirbtlement of the nickel This action has resulted in breakage of dip legs in the meltdown vessel at the rate of one dip leg per run Breakage v observed to occur in the gas space above the melt and the broken dip leg falls to the bottom of the meltdown vessel where it is available for further attack by corrosive material) dissolved in the salt After melting batch
TaMe 93 Impr i t in tm raw material mtei ia ftmoriit a l t production (ppm)
Component S Si Fe Cr
Component Av Max A Max Av Max AVK Max
L i l 21 44 100 IllO 20 25 lt l lt l BeF 300 500 IHO I0O 50 100 20 40 rl ir- lt M 0 ltIO0 lt IO ltin 25 62 I I 17 Mixed raw
material^ ino 131 47 47 26 56 9 15
Mix ture required to produce tali havirfi compofll ion of 72-16-12 mole i I i l - B e l - I h i -
166
FS-101 was passed through a nickel filter having a mean pore size c f 40 i but plugging of the filter on subshysequent transfers led to its removal from the system Transfers from the meltdown vessel are now made after allowing a period for particulate material to settle
A stainless steel dip leg was used in the meltdown vessel during the melting of batch FS-105 in an attempt to avoid cracking of the dip leg The use of stairJlaquolaquo steel was liter concluded to be unsuitable because of the increased concentrations of iron and chromium observed in the resulting salt product The dip leg did not embrittle nor break during melting of the salt but extensive corrosion was noted on the submerged porshytion of the leg As a result of these observations a dip leg of copper and nickel was constructed by placing a copper sheath over a heavy-waD nickel tube The nickel tube provides rigidity and the copper is used both outshyside and inside of the nickel tube to obtain resistance to corrosion The copper sheaths are welded together at the lower end of the dip leg located in the meltdown vessel This combination of materials is expected to result in an increased dip leg life and less contamination of the product salt
An error was made in charging the ThF4 for batch FS-105 which resulted in salt that did not have the desired composition
922 Hydrofluorination and Hydrogen Redaction
After a salt batch has been melted in the meltdown vessel it is transferred at a temperature of about 750degC to the processing vessel where it is sparged with an HF-Hj mixture at a temperature of about 625degC for a period of about 10 hr The salt is then sparged with H 2
at 700degC the H 2 flow rate of 10 std litersmin used during the hydrofluorination step is continued for 30 lltr to reduce iron and nickel fluorides to their raquoraquopective metals
Progress of the hydrofluorination step is monitored by determining the HF content of the HF-Hj inlet and exit gas streams by absorption and titration of the HF in a metered volume of exit gas When the HF concenshytration of the inlet and exit streams becomes equal (or the concentration in the exit stream becomes slightly higher than that in the inlet stream) contact of the salt with the HF-Hj mixture is stopped A relatively low temperature about I00degC above the salt liquidiu temshyperature is used to minimize the rate of corrosion of equipment and to maximize the rate at which oxides are hydrofluorinated The hydrofluorination step is folshylowed by treatment of the salt with hydrogen at 700degC
to reduce iron and nickel fluorides The utilization of hydrogen during this step is low and large volumes of H are required Since the reduction reaction releases HF the concentration of HF in the off-gas stream is monitored and hydrogen treatment is stopped when the HF concentration reaches a low value (about 002 meqliter) and remains constant within the detection limits of the titration method
The total gas flows (H 2 and HF)during the processing operations are shown in Table 91 The values in the table reflect a steadily increasing quantity (from FS-101 to FS-105) of HF generated by H2 reduction of metallic fluorides that can be ascribed to a buildup of metals (largely iron and mcke) in the salt heels in the meltshydown vessel and in the processing vessel during operashytion These metals are converted to fluorides during hydrofluorination and thus add to the total quantity of metal fluoride to be reduced during hydrogen treatshyment
9 3 SUMMARY
The information presented in the previous sections indicates that the following factors are important in producing high-quality salt
1 Analyses of the raw materials indicate that there will be no concern with metallic contaminants unless metallic corrosion products are introduced during the salt purification or melting steps
2 The sequential buildup of metallic impurities in the salt produced in the I2-in-diam facility is the result of corrosion of the equipment This corrosion can be minimized by use of copper whenever possible when equipment is simultaneously exposed to salt and process gases Periodic hydrofluorination and discard of flush salt in the processing vessel should control any minor buildup of corrosion products
3 Although not demonstrated by data shown in this chapter it is believed that oxygen contamination can be held at low levels by maximizing the removal of moisture from the raw materials before they are melted and by improving control of the hydroshyfluorination process A method for measuring the H 0 produced by reaction of HF with oxides in the starting materials is being tested This should aid in determining the proper time at which to terminate contact of the salt with the HF-H2 mixture Alsoit may be necessary to determine the sulfur content of the off-gas since this may be the most difficult conshytaminant to remove from the salt
MOLTEN MLT REACTOR PROGRAM AUGUST lraquo4
i I MtfttitSI HHMHAM OIHH UgtM
m D M K M AMD M V I LOMMlaquo1 i n iH tGlL H
svsriMi AO AKAIVHI J N I N C U H
1 j A L L I N H
H 1 K | N lt I N
0 1 M A S M
0 I M I D N
ftWIMt A N C O f t M O M H T l M V I L O M N N I
m M G u laquo laquo O N H
A A H U - t U t l 1 M
W 0 H l V l M f t M N M 4 ft M l i l M H
m bull raquo | N S O N H 1 ftlOOLl N O t I R A V H I N M M bull H O raquo l raquo raquo S O N n
bull F A I M M O N M I M
4 M L V l l C L C M l M i S H V D i V t S i O N C M l W l t t N T D V I K O A j C M l W C A k F I C M A J O L O C J V 0 V gt V O V lt TACS A N D C A A W C S lgt iV traquo iC i M A C T O M ) O i V i S lt O N I X m v l f t S l T V O I I I N N t M I l
A t A H H I A U
M 1 M C O V MAC
M J U H U 0 Y N 1 T U W I I
H 1 I f c C O l MAC D N bull M lt S gt i MAC 1 M K h l S I A D MAC A k C L A J J I N C MAC I I J C X O U t t MAC
1 A U S T M A N G MAC
H l H I I I T A N t l MAC C A H V M A N M J laquo K t i t t H MAC
bull C U S U I MAC
bull M r N A M MAC 1 K R U C M I MAC A C t C M A f raquo M A U S ( H MAC i ft W O O t i S MAC
C M 4 M I C A L M K K I U 1 I M M A 1 I A I A L I
H M U I W V MAC
I I C H N I C A I t U W O I I t
A V HOI I M i MAC C 1 0 o N MAC n M raquo 4 H M t M - MAC 1 C k l l T N t H MAC J t I M i l H I H MAC I M l A r M l H L V MAC
J 1M H I N D I I C K S MAC T t M I N S O N MAC J 0 M ICWON - MAC
1 1 l A M H I X i 1 MAC
1 bullbull I I I MAC A ilaquo M i l l k H MAC (1 A gt 0 1 T1H MAC
I d H A H D O h MAC H H V I A M N O k MAC 1 i X M I M S K V H
tt I I S 1 I N I S MAC C K l i K l M A S MAC 1 H r H D I I I M MAC C A W A l l laquo ( l n 1 1 M K I C I H O I I S I MAC
M M gt H O C I t t l a O I V l l O r W I N I
J H Mt r HT ( )WraquoM IH bull
C M I M I C A l 0 I V I L 0 A M I N 1
A O fttk M l M S M H I I N M M
l O l N l l f t l laquo a O I V l l O H H N 1
gt H H I U H f O W I H JH C M SHOWN m n M c o i m c i c w t i bull H bull U N O A U l H M C S V A lt i
I B I A M S H O P A Y M
M M H C H I M I I T M V
l M M H H i S i A 1) r l L M I H S c L M A V A ( H t M t I C c raquo C A N T O N c I M l M c t O d i LPS T H I C K c raquo A r o i i raquo bull t H N M H O N k l U N t
D 1 H l A T H f R i V 1 O V A L l N l l N I c
A N A L Y T I C A L C H I M l t T N V
M M A A C H A f t O O I V I t O M M I N V
A I M f V I N AC H t A M | t bull AC B H C l A M K AC J M M A L I AC p L M A N N I N l t AC J P T f l U N t t AC
A N A l V S f l
i i I I M raquo I M At t it O o r t M - A l
ft ri i A i N t AC J A C A H I t l f AC
C O N S U L T A N T
r M A M A H t O V I I I
_ -L_ ULTMOOUCTION N M HtWIQN c bull I U A l t v C
bullH i AHVAK C I A c XJHNtOkt C t
1 M Mpoct raquo olaquoc laquorf x laquornrraquo v4 IMA MIMA Weuro M C I MIO
i t a k trpoffe iHji AcwriM tnr ptoyrc bullgt the (aopun Ilihrgt c^wt i==v agt
0 laquo M 4 4 K M bMg 1 M V gt 31 Ilaquoraquo O K M - raquo tow (aMj CViltn 31 W ( K M X U total E M M J laquorgt 31 I OlaquoM raquo tow IKM laquolt gt-iraquo 0laquoM7raquo tonJtJMMfMgt3lllaquo5laquo ORMOSlaquo tnaikmtmtOctlt+tt HI (MSI m D m (tthnj teraquogt 3I JMI ii 30 |ltlaquo0 OKM-3QI4 tomJ fattMf Mgt 31 IlaquoMO ( K M 31 towi fawMf Frmgt gt Iltl OHM 321 lt towrftJMMf AMMM3I Ilaquoraquo OmSLi^Z total FMIMJ Hbrmay gt bull- ORM-334 tomt tJnf AMWlaquo 31Ilaquo ORM-34P to MOM Jmraquogt 311laquob3 0laquoL-35gt totaj tMJwf JMgt 31 IMJJ ORM-3raquogt towl EMM tani 31 fM O t M r rrd M Mgt 311laquoM OHM-3 I towJ to FVfrfwry 3gt bullbulllt OKM-sraquo total EMM laquo laquo i 31 Iltraquolt ORM-gt3b totaJ EMM F4MMgt gt IlaquoraquoM ORM-K~ to vlaquo MAM M J1Ilaquoferaquo G4LM4I J tow EMM i n laquo gt raquo I W OHM-raquobullraquo ftnud EarfMf Ailaquow4 3 bullraquo aM-raquolaquo4 toraquoi E M FlttNlaquoHgt i OHM4344 total EMJH Ktfmt 31 IltM OftM-ll towi EMJM FfMfgt gt Ilaquoraquoyenraquo ORM444 totaJEiMJ3llltraquo OfcM 444ft toml Eraquofc F4WlaquoM gt I OftM4j total b u b tmgmt 31 laquobull OftM467 feftal EMJM Flaquofcrmv bullraquo Ilaquo7l 0RM4gt total E n 31 I7| OftM47iC torn EMM Flaquoflaquoy -^ llaquoraquo OXM4K3 total EMM AapM 31 17 OftNL-5011 total EMM AMlt 31 I4 ORM-ttM towl E n FlaquoraMgt gt W
Coimnti
SUMAftY
PARTI mm KUCM Aim vcvujonmsj t v^SItMS AND ANALYSIS 2
raquo l n t t raquo bull ( bull bull laquo a Mete SJpound nam I I M 5 M C J U I M raquo 2 1 I r laquo 4 w t Srfl TlaquodMc4ap FMhn 3
I 2 amp w Rftowr raquo laquo sect bull 1 3 mroMi Aaalyws - 9
131 MSMSnrgt 9 l raquo TXr tCraquoo 12
14 t t^TcnpctsnMrDNpi I te fe 12
2 s m t J t S A X P C O I 0 9 ^ T S 0 m U gt r M L T 16 21 l t -Sgtnn TfdMofofy Fac 16
211 Crwraquomwiw4$rfihmdashySgttnOfcltjtiraquowi 16 2 12 S-ftowraquo^vfuiwHWif DWraquo3MCJamiilaquoirfVjnjWrnuwteimcraquogtn IS M M N ^ F laquo W M I F W 19 214 P w i mtmmiH 22
2 2 Claquo4aM-Sak T laquo f c raquo w F n iCSTFl 22 22 1 UvOMYJCM 22 2 2 M M M T M 23 223 TIMM Ei^tiMm 24
23 Ftwcrtf rlaquonlaquocimi Lon^sect 2 23 1 0prraquoiMigtfMSR-FCl-2raquo 26 231 DtwptmiCamnKnmafKVymtifCL 2
PART 2 IMLMSIRV
3 FUEL SALT CHEMISTRY 29 31 C n y i i i mttkt Lirtitmdashi Trfcinw Syami 29
3 Sprctrawoyy of Tcnprtan Sptctn n Manni Swu 30
3 3 Thr UrjMHMi TrirjIWori - H y d w y Ci|iiraquonmdashi m Matio Fhwnic SahMww 31
34 Fwam EJrctra S w laquo n laquo Mate Salts 32
35 Flaquo4 SafcladMi Sad lmnmttm Snafcn 34
36 Laiiior mamp FOWMHUH LJuMptcs of Fw-Ro TraMOc Meld Fbariafcs 37
ii i
IV
4 COOLANT SALT CHEMISTRY 4 4J ClKMtfiY ut SUAMW Ftourakcwa 41 4 2 CorrusmofStiuvinralAloysby Fmoroboraies 42
5 DEVELOPMENT ASD EVALUATION OF ANALYTICAL METHODS 44 51 m4aKAnafestraquo of Molten MSMtFnel 44 52 Tntmni A t f M Esperanents bull t Coutat-Salt Tedhnofagv Facnfcty 45 5J Ekctnlaquo^Kfic^Si^Maflralaquoll|aiMahaiLi -BeF -TM laquo
( T M 6 - i laquo ^ l 47 5 4 Vidummetnc Sankes of Tdnmnn m Molten LnT-BeF -ThT
lt2I6-I2 bull-gt 48
PAST 3 VUlERlAI^ DEVELOPMENT
6 DEVELOrMENT OF MODIFIED HASTELLOYN 52 61 DewelapinesM olt a Moitei Sait Test Fscdicy 52 62 rVocnmneai and Fabrication of Experjnental Almi 65
6-21 Production Heatsof 2 TiJIudrtied HasieRoy X 65 622 SltMfraquooictraquoltNi Keats of 2t TtModmcd H s N
Cammm Stdbmm 6raquo 6J WeMabiny afCanneTcni AlowgtModified HastetVn N 69 64 SUDdm of V m w Modified Hmrikn N Aloys m me
L nnf jdmed Condition 74 65 Mtdumcai Properties of Tiljmdashw Modified Hasietttn S Aloys
bull nW Umnndnied Condition 7 66 IVMirrsdnmn Creep Properties of Modified Kxuelloy N 82 6 7 Mkratntctwral Anah-raquos of Tnawm4lodified HastetVn N 84
671 MKroMracwnl Analysis of ABoy 503 and 114 85 672 HomopefctotisHastctoy S Aloys 88
6Jraquo Salt Corrosion Sindies 91 681 Flaquoe Silt Thermal Convection Lraquoraquops 93 682 Foci Soil Forced Circulation Loop 94 6 J raquo 3 CoolaMSalt Tfcennal ConvectionLoop 94
69 Corrosion of Hasaenm N and Otner Aloys m Steam 97 610 Observations of Reactions n M-talTeiliinum^i System 100 611 Operation of MetalTeHvnam-Salf Systems 101
6111 IHkumm Experimental put gtunVlt I 101 6112 Oironnnm Telunde Snfcmrfity Exprnmer 102 6113 Temjnwrt Experimental Pot Number 2 103
612 Gram tnawdary Embrittleinenl of Hasteiloy N by TeHuriwn 103 613 X-Ray Identification of Reaction Products of Hastetloy N
Exposed to Trikimm-CnnianMnit Eimromrents 107 614 MetaflografnW Exammatmo of Samples Exposed to
Telwnum-Canianwnii Environments 108 615 Examination of TeGcn-l P 119
6151 MeialopaphK Observations 123 6152 Chermcd Analyses for Temirium 124
V
fc16 Salt Prepantni aad Fad Fm Fafelaquo for TEGea-2 aad -3 131
7 FUEL PROCESSING MATERIALS DEVELOPMENT 132 71 SUCK CapMkTlaquob of Gfwhile with BoHMka^
bullKawm-Lrifcaaa SUMIMMK 132 7 2 Thermal Grlaquoaer Maraquo Transfer T laquo of Graph
maMofcMeaamLoap 133 T2I Wea^tChanan 133 722 Coaa^sttoaalCkaaats 133 f23 MkroMractwraiOnagri 137 7 24 DBcmsHN of Rente 37
PART 4 FUELPROCESSMC FOR MOLTEN-SALT REACTORS
a ENGINEERING DEVELOPMENT OF PROCESSING OPERATIONS 142 HI Metal TransferProcessDevelopment 142
111 Addrtion ltM Safe and turna Pka^ ir Metal Transfer Experanezi MTE 3R 143
12 R M d-l 144 a13 R raquo V 145 al 4 DrwwKM of Remits 145
a 2 Saftntoaiwir Contactor Dewdopmenr 147 H21 Lxpeirnents with a Mechanically Agitated Nnnitiprnwi Contactor
bull ike Sah-Ruamth Flowthronfi Facaify 14 a2 Evperiments with a Mrdumcafry Agrtatcd Vindiipri mi
omactor Una water and hVrcury 149 H3 Contavjoas Fhjonaator Devdopmert 152
a3 I histatbtion and Initial Operation of Autoresittance Heatmi Ten AHT4 152
a 3_ Drsam of aCoatamons Fuonaator Expenmeat Facdny iCFEFl 155 K33 Hmonme Disposal Sync for Md 7503 156 H4 Frozen WalCorrosion Protection Demonstration 156
a4 Fad Recnnstifation Enpneernt- Development 15 H41 Imtnaneniatton lor Anatynap Reaction Vessel Off-Gases 15a a42 Deng of the Second Fact Reconstitaoon Eapneermc
Experiment 160 85 Conceptual Deagn of a Mjlten-Salt Breeder Reactor Fad
Processing Engiaeermg Center 161
PART S SALT PRODUCTION
9 PRODUCTION OF FLUORIDE SALT MIXTURES FOR MSR PROGkAM RESEARCH AND DEVELOPMENT 163 91 Quantifies of Salt f-rodaced 163 92 Operating Experience in l2-m-diam Reactor 163
921 Charging and Mrfimg ltA Raw Materials 164 922 Hydrofluorination and Hydrogen Reduction 166
93 Summary 166
ORGANIZATION OIART - 167
PAST I h B M D E 5 raquo r a AND DEVELOPMENT
J REnael
I Srsvcavaad AmJrait
CaVnaatnms c4 the expected trnmm tcknor in refoessce-deagn MSMt a m loatmuid wall stmVcs of the uoanbte effects of ovale rams on heat ex chaff surfaces in the steam system and on surfaces exposed to the ccmaimmtm atmutawew The presence of oxide A n vjnraquoH laquoery km ptimubmty on the heat toaster surfaces would SMstnVaaey reduce the rate of intmm nwgrgrion to the steam system became of the mciemmg importance laquoltf the oxide-Am resistance at very km parshytial pre a w i of hydrogen and irnnaa l lowexi the reduction irom this effect alone would be rnuufficieut to heat rbe rate of tritiuui msginion to the steam system t J denied tames At rates ltd tritium irans-pori le the steam system the presence of oxuk-fam rcastatccs ltm loop wait tends to mcrease the rate of frinsra Hem mto the steam However tins effect a mukpufkaat at the low migiatiiw rates required
Potential ^inbwuonj of tritium m the ruotmt-Snh Technology Facmty were estimated for the cundrtmus o planned expenments In the absence of inborn rater-^ctioe with the salt other than mnpk ihisututici as ranch as laquoW5 of the added tnthaa cowU be expected to escape through the loop wals Removal of significant fractions in the loop off-fas coaM he expected uaH i the effective permeabmty of the loop watts were 10 to 100 times less than that of bare metal
Substantial chemical interaction of tritium with Nnaf 4-NaF was observed in the two tritium addition tests performed Ratios of cornbmrd-to-efcmnilal tritshyium in the salt inferred from elemental concentrations in the off-fas and combined concentrations m the sail were 50 and 530 for the two tests Approximately pound to of the dded tritium was removed in the off-gas stream prindpaly in a chermcaay combined water-soluble form
An undated aeutromes modrl raquot the lOOv-Mtftci releteace-dcsam MSMt r heme developed Muhi-duneanuaat mntagioap cakwUtmas wdi me the VENshyTURE code with newt run crosfsectson data dented catNcK from the fcNDF-IV Wwantv Pruoriune bull the croavteefMW dau was completed tor 3 otJraquo nachdo at lorn temperatures gtJt mtemi lot the planard cakvb-i m v Crow-stetson dau are also heme exammed it the two-step thenaai reaction Nangtr lt Naij i lrf winch is expected ilaquoraquo be the principal to sxe ot hebum m MSMt stractaral metals
A review of i he dau and cakubtsuns medio estauatc tdtunwe mveutories m the TeGen-l experMKM m-catesanuaccTtamtgt ltbull Xr
Work raquo contmaHNj raquo the udgt bullgt thrruul rotvh-ettmg and creep fafaw m react vtrwctural nuternh Analytical ractbodS are bemg developed which wdl be apphed Ss reference-design MSMt ilaquogt evaluate the significance of these processes m HattePoy N
The (ins-Systems TechnoVigy racdtty was ilaquoperated with water throughout the report ptnod Efforts to reduce the annua um ltH the salt-pump shaft oscdbtiom have been unsuccessful The jmyunudt of these oscdb-tions rs brgety dependent upon vk laquoi w ed so a bger-dhmeter imprler which wnl give the design flow and head at kmer speeds rs heme fabneated A method was developed for estimating the pump fountain flow Smce this flow was higher than desirable bach vanes wtl be used on the new rmpener o bnui the How Tests made at the loop indicate that the densnometer can be used to determine bubMe-sepiralar efficiencies if short-term tests are used
Routine operation _ltf the (oobnt-Satt Technology Facility was esiaMrshrd with more than 50Ghrof sah circidation without plugging in the loop off-gas Nne Measurements of the amount ot salt mist in the off-gas stream showed 100 to 500 ngcm iSTP) depending on
VII
1 M
w
l t
I BLANK PAGE
bull-laquo-
laquo t u
the a l t temprrataK and the I F flow rale MMO ike loop gas space The M M trap awtaard m the sah cold trap was effectn m meanta ike pm^mg hraquot had been expeneaxd earner Two i m i a marcoon lesti bullere coadacteJia whjch 85 aad bullraquo cwTi teaarvtwds of ifitmed bydropea ere added to the loop dame two I04raquo periods- Ficqaeat n i l aad off-gas sample were takea to mumlor the tRtaaa bebamor m the kwp
The torcedltoarctwa loop MSat-FCL-2b has accw-rautatcd MOO hi of oneratnaa with MSMl reference hart vdi at deaf ^ r coadmoas wrm riW expected low O M -roaoa rates Dbu oMaawd oa the beat master ckarac-terufacs of das sak air being aaafvard The deaga B eaeaadK complete for torced-coawectioa loops FCL-3 aad FCL-4 Coaaaoaeats ate beaaj fabricated J dec-tncal a i i f lHwia is proccediag
PART 2 C V E M S n t Y
3 Fari-MtCfceaaMry
Refachch pare Li Te lahoat lt oa a mole haasi bullas piipaatd by the coatroaedaddrooaof Kaaraaa to Hiaad hdnum The lac tam was began at 15QT bat afciamefjr tempt Mimes greater thja 50tTC acre reshyquired to complete the reactwa LiTe was prepared by rcactmg the aoidaomrtric amounts of LijTe aad tcfa-raan f o r brat 550^0
Apparatus for the spectroscopic stady of letunam species ia MSMt far salt has beta aaeaawed rYeima-nar work am hnmaa teshmars ia cbkmde taehs has shown ant at least two Mfbi-abjurbaig spears are present wirh uwapoatuai at the raja Li-Te to UTe Farthenaorc stadia with T e ia LiO-KCI eatectic have shown that laquo addition to Telaquo a lecoad species is present at high lemperatewH aador lag habie km activity
Apanxtm for the qtearoihotometric stady of the conawriam UFlaquo(dgt bull 4H 2 iggt = UFidgt bull HF|graquo has beea assembled aaa measurements using LiineF as the sointnt haw begaa A prehaaaary valac of aboat 10 was obtaiacd for the eqiaktiiam quotient at 6S0degC Tins vaiae is ia good agreement with the valat obtained pnwoady by other workers
Detopmeni proceeded on porous aad pact d-bed electrode systems as coatiaaoas on-line moailors of conceatralioas of declroactiwt species in molten sail solutions The packed-bed electrode of glassy carbon spheres was caNbralaquo4d using Cd 1 ions in LiCI-Kfl eutectk before experiments were conducted with B ions in solution The results of the experiments demon-straied the cpabdity of the electrode for momioring these and other ions
Preunaaary eiftrraacar i n c conducted iraquo cvatiaic watt ^wntkKM fetatmg to the naxmg bullbulllaquo VaBr - jF coutaai sah with M S M tiid vdi D F - f k f - H i r 4 F tMfc-ll ~-0S mute I Ibe result showed that ihr rate of erutatjoa oi BF gas raquoa naxau was low Mi vac of sanf amounts m coolant vdi wtth fael tab Jal bulllaquo result at the purctpttatam M aramam- ltlaquoc ibiwaaa-coataaaac -antpuands Vlt data w^re abtaaed +m ibr aaxaa M sanfl aaamats ot farl salt wwh o4aM vW( HesahstHeiprraataiiMi whvh a satal amtaai ot on-l aat salt cuataaaay igtxale was aaed with tael salt sae-eraed d m oude speoes aawe stable dun I O wlaquotc pMseat smce bullgtraquo pitecipitjnua of I O was raquodraquosrtraquool
A stads ul laztice eadadaKs ot tirst-ruw traassfiua-atrial (Wndcs was aadertakea to proadr a theraquofciicjl basts laquobullraquo ii itll Haw thrnancbrnacal data Urn uraLiaial metal tlaondes bratg obtaated from mm4 eitctrcisie gjiiaaJL ceKs I igaadnrid comctamsto pkxsul lattKe emhapy laquos ttnaat aamber for the rwraquoraquo senes CaF laquoo laFz raquo ScFgt to GaF mdkaied that dte staadad embdptes at loranfua plusmntf gtol N jad V F weilaquo saostaclors bat dial a m accante expcraaeatal lamn of Sit fur T i F V F O F CrF F e f aad FeF woald be deswabh
Analysrs tlaquot raaplr i ot coaJeasate coarcted danat opnaiwa of the Cooba SJ Tccbaolagy Facigt nahcate that the mpur aboar the gtali B aot a taaie mokvafar coeapoaad bat rather a auxtarc ot stamk gateows species sach as H 0 HF aad K F The coadtn-sate dtowed a intmm coaceatratioa ratio of aboat 10 rentiwe to dar salt Tha resak tajatsts a pinablc method for coaccatrafiag aad collectiag tntiam -a aa MSMl Related work showed that NaBF0H dnnohed ia ^ltobal sah uadergoes a reactwn that redaccs the OH ~ coaceatratioa m the salt prodacmg a mbtde frac-tkm Phyacal aad chemical obstrtalioas were made on the sysem VaF-NaBF-BjO at 400 lo oOtfC Work with compoaikms typical of ibe usual coulaat salt (oxide coaceatratioas up to 1000 ppm| showed that at least two oxygea-ooataaaag species are present One species n N a raquo F raquo 0 the other has not yet been bulldenirfied
Slddtes were continued o determine the extent lo which borides were formed in Hbstetoy N and btcoael 600 by reaction with NaBFlaquo-NaF at 640degC Data obshytained thus far indicate some formation of chromium and nickel borides however after four months of exshyposure of the alloy samples lo sal the boride concentra lion on the metal surfaces did not exceed 500 ppm in
I X
Haste X and 1000 pom m hwoaci MM) The tcvdh jhraquo dtuwei that A n mdash i n n these laquobullgtbullgtgt was setec-incigt gtraquodued by rhe salt
IkMb thrv period I I ~ ratio were oMMoted by laquogt4taaMneirv lechnnnsrgt in imu rhetmai-cunvecSoa loop and ltAC oiced-circgtdaraquooa loop Subie redox mo dnom H4MIHK bullbull exist m tbmnal-convrctiou loops U A ) 2V the I I ut9raquo raquo approximately T A IO ani respectively In forced-cunvectampn wop H I - gt she I I rlaquoraquolaquo n about copy Vraquo meinpfs feme et Keen ante laquobullgt reoxuJur the I i fhe melt by the addition ot mchet tiuundelaquolaquo some other oxidant
The results rora the fast series of tntnuu ldditmn experiments at the ( raquo u b n - U i Tcdmulugy Facem ltholaquo (wraquo ten tattle mimm exist m the off-gas m the ctesnental state the bwtli of tbe tntruei ltvwi at i iuai-huved laquo water-Mi Ale K m h appears thai about W of the uuecttd inmm experienced tvawticanf holdup raquo thr salt -and was eveutualy remmed m the system ott-
It was observed that the Fe - Fe electrode reacshytion n molten LraquoF-leF-ThFlaquo lt~2-l6-l2 mok i ckfseH approximates the soluble product case at a guid electrode the inwduMc product case at pyroiytic graphshyite and- deptwdmg on the temperature both soluble and insoluble product cases at an indium ekxtrode
Yoffarmarirw measurement were node m muMen liF-nVF -fhF 4 toSowute jddrtiuru tit Li Te is an effort to identify soluble etevitoactive lehurium species re the melt No soitammetnc evidence of such comshypounds was ohtaated These observations were m general agreement with cherracal analysis that indicated lt5 ppm Tern the salt
fAKfi MATEMALSKVF4j0PMtIVT
u Dtncfupmvnl bull bull MMuinJ lunumvy 3
Work raquo parfnHy complete on the molten-salt test facrlrty to he used mostly for mechanical property testshying Much lt (he test equipment is oprralmn
Alt products except the seamless tubing of the V-Ti modified HasteHoy N were received The first heat weighed lOjOOO Ih and had a fairty narrow working lem-prrature range- The second heat weighed WOO lb and had a wider winking temperature range Seamless lubing is being fabricated by two venders WeMahility studies
on these two beats showed bat their urldnsg d u n e lettstacs were euuwahm to those ut standard Hatfefoy V and thai extstmg wetdng procedures ut standard HaMcwoy could he used fur the y Ti Audited
The mechanical properties of HasteBoy gt inuiiaed wwh ifUnMtm nwhrum aad aiunuMun were evahaied m the undated and uwrradnted MB These piupertjcs were umd to estunate tfae mdwudwd and courtuntd wOBceMtauans of Manwani muhwun and ahnuuHnn reouwed laquou produce bntrte mienueuBK phases The tomnuuu ot brstrk phases m the aloy n i t mdash n muwuni was enhanced by an apphed stxss
SpeciBMns ot modihed HnseSoy were exposed to idlunuw from several dMterewi sources Tbe partial pressure tH tewynum above CrTelaquo at TOO C sMtm reasoatfjty dose to that anttcaujied tor MSMb Metal-lugraphic e-umnitiua o tbe exposed specuuens aite strauwnt revealed iblaquo aftoss coniauung OS to I Nb were resttfant to neTgnnular craefcrng by teiurrum
Further aaatysn ot the data lrlaquown TeGen-l showed that most ot the tdunum m each fuel p s was coircen-tafed on the tube wall The concentration bullraquo the salt was I ppm gtrr less The salt bssbcen preparew igtit gtugtng the fuel pur m TeGen-r and- and the puu tor Telaquoelaquo-- base been assembled tlte tuhng
t ipenments were contused laquobull-gt evaluate graphite as a matenal tor fuel prlaquolaquocrsssng apphcaimus The peneira-tmn ot graphite by buRtuth-utbimn suiutnms was found tigt increase with mcreasmg lithium concentration of the stdutKm and pore diameter of the graphite Decreasing the pore dBrneter or the graohae by pitch impregnation decreased the average depth of penetration However because fhe structure of the graphite was sarobie greaier-fhan-average penetration occurred m reginns bullraquo low density
A thermal-convection loop construcied 01 irkdyb-denum conumed ATJ graphite specimens in hot- and cold-let reports and circulated Bt 24 wt bullbull 141 at t Li for WOO hr at 700 C maximum temperature with a temperature differential of I00degC Very large wetghr mcrextes tJO to tgtT~ cccurted in ail ot the graphite samples primarily as a result of bhmuth intrusion into the open piMouty ot fhe graphite Disamclar-metal mass transfer bet weep molybdenum and graphite was also noted These results and previous capsule test results suggest that fhe presence of mofyhdenum enhances intrusion of bifrnuth-lithium solutions into graphite Thin carbon layers were noted on the molybdenum
X
PART 4 FUEL PROCESSING FOR MOLTEN-SALT REACTORS
8 EsgMecfMg Dcvdopraest of Piocessiwg Operations
Addition of the salt and bismuth solutions to the process vessels in metal transfer experiment MTE-3B was completed Two experiments were performed to measure the removal rate and overall mass transfer olaquofficients of neodymium In the first run about 13 of the neodymium originally added to the fuel salt (72-16-12 mole UF-BeF2-ThF4) in the fuel-salt resershyvoir was removed durine the 100 hr of continuous operation Overall mass transfer coefficients for neoshydymium across the three salt-bismuth interfaces were lower 1ian predicted by literature correlations but were comparable to results seen in experiment MTE-3
For the first 60 hr of the second experiment which was a repeat of the first experiment the rate of removal of wodymium was similar The second run was termishynated because of unexpected entrainment of the fuel salt into the lithium chloride in the contactor which resulted in depletion of the lithium from the fh-Li solushytion in the stripper and stopped further neodymium transfer
Future experiments in MTE-3B will depend on detershymining the reason for the unexpected entrainment of fluoride salt into the lithium chloride and it will be necessary to remove and replace the lithium chloride that is presently contaminated with fluoride salt
A hydrodynamic run intended to determine the effect of increased agitator speed on the extent of entrainme w OIK phux uw tne other in the salt-bismuth conshytactor was performed No visual evidence of gross enshytrainment was found Analytical results indicate that the bismuth concentration in the fluoride salt phase decreased with increasing agitator speed This unshyexpected result is probably due to sample contaminashytion
Development work continued on an electrochemical technique for measuring electrolyte film mass transfer coefficients in a nondispersing mechanically agitated contactor using an aqueous electrolyte solution and mercury to simulate molten salt and bismuth During this report period experiments with Fe-Fe2 were nude with improved experimental apparatus A stanshydard calomel electrode which enables measurement of the mercury surface potential was obtained Electronic filters were attached to the inputs on the xy plotter to damp out noise in the signal to the plotter Near the end of the report period a potentiostat was obtained which will automate the scan procedure now performed with
the dc power supply Copper iron and gold anodes hjve been tested The gold anode is the most satisfacshytory choice since it does not react with the electrolyte solution By noting that the active anode area in the cell could be decreased with no resulting change in the difshyfusion current it was determined that the mercury cathode rather than the gold anode is polarized Results indicate that the ferric iron is being reduced by some contaminant in the system Further tests with purified mercury and electrolytes in the absence of oxygen indishycate that the contaminant was present in the mercury Analytical results for Fe and Fe1 concentrations in the electrolyte phase are inconsistent with expected results Qualitative results indicate that a buffered quinone-hydroquinone system may be usefid as an altershynate to the Fe-Fe2 system
Installation of autoresbtance heating test AHT-4 in which molten salt will be circulated through an autoresistance-heatelt test vessel in the presence of a frozen-salt fim was completed and operation was begun A conceptual design was made of a continuous fluorinator experimental facility for the demonstration of fluorination in a vessel protected by a frozen-salt film Design was completed and installation was begun on a fluorine disposal system in Building 7503 using a vertical scrubber laquoith a circulating KOH solution Inshystallation was completed of equipment to demonstiate the effectiveness of a frozen-salt film as protection against fluorine corrosion in a molten-salt system
Off-gas streams from the reaction vessels in the fuel reconstitution engineering experiments will be conshytinuously analyzed with Gow-Mac galaquo density detectors To determine whether hydrogen back-diffusion in the cell body will be a problem during the analysis of the HF-Hj mixture from th hydrogenation column the cell was calibrated with NJ-HJ mixtures It was found that when the reference gas flow rate to the cell is suffishyciently high i effect of hydrogen back-diffusion is not seen The second engineering experiment will be conducted in equipment which is either gold plated or gold lined to eliminate or minimize effects resulting from equipment corrosion Several alternatives for gold lining or gold plating are discussed The factors which must be considered in deciding between lining or plating are listed
A design is being prepared to define the scope estishymated design and construction costs method of accomshyplishment and schedules for a proposed Molten-Salt Breeder Reactor Fuel Processing Engineering Center The proposed building will provide space for preparashytion and purification of salt mixtures for engineering experincnts up to the scale required for a 1000-MWfe)
l
MSBR and for laboratories maintenance areas and offices The estimated cost of the facility is SI5000000 authorization will be proposed for FY 1978
PARTS SALT PRODUCTION
9 Prodactioaof Flwnde Salt Mixtures for Research and Development
Activities during the report period fall in three categories (I) salt production (2) facility and equipshy
ment maintenance and modification and (3) peripheral areas that indwb preparation of transfer vessels and assistance to others in equipment cleanup
Salt produced in this period totaling about 600 kg was delivered in more than 30 different containers About one-half of the salt was produced in an 8-in-diam purification vessel and had acceptable purity levels The remaining salt was produced in the 12-in-diam purification vessel during five runs each of which involved about I SO kg of salt
Part 1 MSBR Design and Development JREnge
The overall objective of MSBR design and developshyment activities is to evolve a conceptual design for an MSBR with adequately demonstrated performance safety and economic characteristics that will make it attractive for commercial power generation and to deshyvelop the associated reactor and safety technology reshyquired for the detailed design construction and operashytion of such a system Since it is likely that commercial systems will be preceded by one or more intermediate-scale test and demonstration reactors these activities include the conceptual design and technology developshyment associated with the intermediate systems
Although no system design work is in progress the ORNL reference conceptual design is being used as a basis to further evaluate the technical characteristics and performance of large molten-salt systems Calculashytions are being made to characterize the behavior nd distribution of tritium in a large system and to identify potential methods for limiting tritium release to the environment These analytic studies are closely correshylated with the experimental work in engineering-scae facilities Studies were started in this reporiing period to reexamine the expected behavior of xenon in an MSBR This work will ultimately use information from experiments in the Gas-Systems Technology Facilitiy (GSTF) to further refine l 5Xe-poisoning projections and to help define the requirements for MSBR core graphite
I Molfen-Salt Reactor Program Staff Conceptual Design Study of a Single-Fluid Molten-Salt Breeder Reactor ORNL-4541 (June 1971)
Additional core neutronics calculations are being made for the reference MSBR using widely accepted evaluated nuclear data and a two-dimensional computashytional model These calculations will provide updated estimates of the nuclear performance as well as add -tional information on core characteristics Analogous methods and data are employed to provide support for in-reactor irradiation work
The GSTF is an engineering-scale loop to be used in the development of gas injection and gas stripping techshynology for molten-salt systems and for the study of xenon and tritium behavior and heat transfer in MSBR fuel salt The faciiitiy is being operated with water to measure loop and pump characteristics that will be reshyquired for the performance and analysis of developshymental tests with fuel salt
The Coolant-Salt Technology Facility is being opershyated routinely to study processes involving the MSBR reference-design coolant salt NaBF4-NaF eutectic Tests are in progress to evaluate the distribution and behavior of tritium in this system
Candidate MSBR structural materials are exposed to fuel sail at reference-design temperatures and temperashyture differences (704degC maximum nd i 39 aC lt17) and representative salt velocities in forced-convection loops to evaluate corrosion effects under various chemical conditions These operations which are principally in support of the materials development effort also proshyvide experience in the operation of molten-salt systems and data on the physical and chemical characteristics of the salt One loop MSR-FCL-2b which is made of standard Hastelloy N is in routine operation two others to be made of titanium-modified Hastelloy N are under construction
1
m BLANK PAGE
L Systems JR
11 TRITIUM BEHAVIOR IN MOLTEN-SALT SYSTEMS
Studies to elucidate the behavior of tritium in large molten-salt systems were continued in this reporting period Additional calculations were made for the IOOO-MW(egt reference-design MSBR to examine the effects that an oxide film on metal surfaces might have on the distribution of tritium Analysis of the informashytion being generated by the tritium addition experishyments in the Coolant-Salt Technology Facility (CSTF) was begun As additional data and results are developed they will be incorporated into the MSBR studies
I l l MSBRCakvbtioas
G T Mays
Calculations were performed to examine the potential effects on tritium transport to the steam system caused by the formation of oxide films on the steam side of the tubes in the steam raising equipment of an MSBR Th rate of diffusion of hydrogen (tritium) through metal oxides typically is proportional to the firs power of the hydrogen partial pressure in the gas phase as opposed to the i power for diffusion through metals (i-e the diffusion process is molecular rather than atomic) In addition at moderate hydrogen partial pressures the permeabiiity coefficients of the oxides may be as low or lower than those of pure metals Thus at the very low hydrogen partial pressures that would be expected in an MSBR oxide films could offer substantial resistance to hydrogen (tritium) permeation However the efficiency of such films would be limited by the degree of metal surface coverage that could be established and mainshytained during operation of the system
The computational model1 for studying tritium behavior at steady state provides for variation of the metal permeability coefficients of the steam-system tubes but assumes that diffusion through the tube walls varies only with the A power of hydrogen partial presshysure Variations in metal permeability were considered in previously reported results However the model also includes the effect of a mass transfer coefficient for tritium transport through a salt film inside the tubes Since transport through the salt film depends upon the first power of tritium concentration (or partial presshysure) this value was used to estimate the effects of oxide films Effective mass transfer coefficients were
Analysts
computed which included the resistances of the oxide films as well as those of the salt films1
Tritium distribution calculations were made for a variety of situations in which it was assumed that the effective permeabilities of the oxide coatings in the steam system were I 10 10~2and 10~3 times those of the bare metal at a hydrogen partial pressure of I torr (130 Pa) These results were compared with cases without oxide coatings in which the permeabilities of the bare metal were reduced by factors of 110 I0 2 and I0 3 The comparisons were made at three values of the UUgt ratio (10 2 10 and 0 4 ) and in all cases sorption of hydrogen or HF on core graphite was asshysumed to be negligible
The results (Table il) indicate that a low-permeability oxide coating would be more effective than a low permeability in the metal itself for limiting tritium transport to the steam system When an oxide film resistance equal to that of the metal was added the rate of tritium transport to the steam system was apshyproximately halved as would be expected (The total resistance to tritium transport was not doubled because of the contribution from the salt film) The results with a factor of 10 reduction in a steam-tube permeability due to oxide formation indicate that tritium transport to the steam system could be limited to the design objective of 2 Ciday However it may be unreasonable to expect to obtain and maintain oxide films of this quality in an operating system
Additional calculations were performed to investigate the effect of reduced permeability of the primary and secondary loop walls through the formation of oxide coatings These coatings can be expected to form in a manner similar to those expected on the steam equipshyment For a given steam-tube permeability reducing the permeabilities of the loop walls would be expected to increase the amount of tritium transported to the steam system With the reduced loop-wall permeabilities less
1 R B Brig A Method for Ctlculalmr thr Steady Sute Distribution of Tritium in a Molten-Salt Bre jet Reactor Kant ORNL-TM-4804 raquoApril 197)
2 G T May in MSR fmgram Semiamtii Progr Rep Feh 2 1975 ORNL-5W7 pp3 12
3 Although ihri calculalional approach assume thai the oxide film i located inside the tubes rather than outside it can be shown that for given oxide and metal permeaMifie this irrangement slightly overestimate the rate of hydrogen permeashytion through the wall
3
TaMe t l Effect of oxide Wmdash on uitmm i todeamtrttmatm MSUtlaquo
Rjti of oxrior raquolaquolaquo laquobull H inlw ltlaquo meial permnbiliiy Imdash 1 tieaw iytteraquo lOday I io nominal metal ratio 0 i d film Redaced meial
prmKabriiiy mvae tlaquobetr prrambibiy4
1 I 0 811 142$ 1 10 J 656 1169 1 10 115 203
10 10= 173 1351 10 bull 10 138 114 10 bull 10 23 198
10 ltf 19 662 10 I 0 J 16 575 10 10 3 142
10 gt w 2 93 10 10 15 84 10 10 lt 31
No wrption of H or HF on core paphtte At a hydropen partial prewurc of I ion
rWith nomnul meul permeability ^No oxide film
tritium would permeate through the loop walk into the primary and secondary system containments eliminashyting a potential sink for tritium A higher tritium conshycentration for partial pressure) in the secondary system would result creating an increased driving force for tritium transport to the steam system
The result of the calculations did indicate that with out the presence of a chemical getter in the secondary coolant more tritium was transported to the steam system when the primary- and secondary-loop wall pershymeabilities were reduced than in the same cases with reference permeabilities for loop wads However more importantly for those cases where tritium transport to the steam system had been reduced to the design-timi abjective of 2 Ciday through chemical additions of H HF or a chemical getter results showed essentially no increase over the 2-Gday rate Thus it appears that reduced loop-wall permeability hat little effect on tritshyium transport for cases where a tritium exchange mateshyrial is present in the secondary coolant
1 1 9 f^^a^af ^dgt T^haMwaflV frMsawv
J R fcneH G T Mays
A 1000-MWe) MSBR is expected lo generate about 2420 Ci of tritium per full-power day Calculations showed4 that unless a major fraction of this tritium
were converted to a chemical form less mobde than elemental HT the rate of migration of tritium through the metal walk of heat exchange surfaces to the steam system could be unacceptaMy high The purpose of the tritium addition experiments in the CSTF is to simulate the general conditions in the MSBR coolant-salt system to determine the extent to which tritium can be held up in the NaBFlaquo-NaF salt There is evidence that hydrogen-containing compounds in the salt may retain significant amounts of tritium
In the experiments the first two in a planned series tritiated hydrogen was diffused into the circulating salt through the walls of a hollow HasteUoy N tube The tritium could accamuiaie in the salt pas into the off-gas system or permeate through the metal walk of the loop to the ventilated loop enclosure Tritium concenshytrations were monitored in the salt and in the loop off-gas In the firlaquo =o experiments 85 and 97 mCi of tritium diffused through the HasteHoy N injection tube For a detailed description of the experimental condishytions see Sect 22
The computer program5 for calculating the expected tritium distribution in a 1000-MW(e) MSBR was modishyfied to describe the CSTF and was used to calculate potential tritium distributions for the experiments under the following assumptions
1 steady-state conditions 2 only dissolution of elemental tritium (hydrogen) in
the salt with no chemicai reaction witn the salt or any of its components
3 all transport through metal walk varies as the power of hydrogen partial pressure
Calculations were made for addition rates o( tritiated hydrogen equivalent to those achieved in the CSTF exshyperiments using assumed loop-wail permeabilities rangshying from the value expected for bare metal to 10 of that value The results (Table 12) show a significant effect of loop wall permeabiity on the fraction of the added material that could escape through the wafts This table also shows the calculated steady-state concentrashytions of elemental tritium in the salt (nCig) and in the off-gas (pCicm) in the same units that are being wed in reporting experimentally observed conjurations Abo shown are the inventories of elemental tritium in the loop walk that would be associated with the calcushylated transport rates through the wafts Since these cal-
4 G T Mar- m MSB fhjpmm Semhwrnu Prop Hep Feb raquo I97S ORNL-5047 pp J 12
i Hraquo bullltbull ami C W N M j r A Method ft e CtkuUting Ihe Sternly Sime DtttrHmitut of Tritium m t Molten Saft Krrrdrr Kemcior Uml 0RNLTM-UO4 (April 19751
Table 12 Calculated rieady-Male tritium diitrrbuliorw InCSTF foe experimental addition rale
Additi on rate Loop wall Tt ilia ted permeability mixture (fraction of hydrogen Tritium bare-metal Kmraquohigt tmCihr) value)
3 1 79 1 10 10 bull 10 bull
3 3 C 93 io-laquo 10 bull 10raquo
Time to reach 8Sf of steady-
state conditions (hrl
Fraction of addition rale which permeate
loop w-y (it
elemental tril removal in oil
turn r1Hraquo
Klvntental tritium Time to reach
8Sf of steady-state conditions
(hrl
Fraction of addition rale which permeate
loop w-y (it
Iraction of addition rate removed
CD Concentration
tpCicmi
concent ration in tlaquolt traquocigi
03 994 06 400 13 95 771 229 I5IKMI 50
38 149 851 55000 200 42 16 984 64000 2211
03 994 06 5(HI 17 103 7$-raquo 243 I90IJ0 (gt4 37 143 HS7 fi7000 230 42 I S 9S5 77tMM 26tl
Irtiium inventory
in metal walk Kti
01 oK 16 17
013 10 19 20
Sail and oil-gas concentrations only longer times required for steady-slate permeation through loop walls
0I tritium in hydrogen
01 I l tritium in hydrogen
t
s
oriatmas represeai steady-state coadmoiaad the nt-naa additioa experaaeats iavolwr t raaskats it a asefal to cuaader the taae renaaed to reach the steady state At high loop-wal penaeabihiies the coaceatratioas of ekaMRtal bullrtraai m the salt aad off-gas are low aad lead to -each steady vataes qakfcry for die additioa rales (see Table 12)- Soaiewhai toager u
aied arith lower assaned loop-wal ptrmdashnbiam hi al cases iidinaiiialjr I n a y times are niaawd to reach steady-stale rates of tiitiaai release throa|h the loop walls However this has little effect oa the triturate steady-stole levels ia the sail aad off-gas
Figures II aad 12 show the resatts of intiwm cua-ceairatioa raeasareaMau v the salt aad off-gas from
are reqaired to reach the higher coaceatratiaas assoo- the CSTF dariag the first aad secoad irilian addition
tn a m - M B laquo raquo
lO _ I 1 - bull ~~l 1 1 1 1 1 1 1 ^ 5 mdash
O SALT llaquoC | )
bull 0raquoT-laquoAS WATER SOLUBLE t$CiJtmh
A 0FF-euroAS ELEMENTAL (aCiar)
1 Mil
2 bull f
bull0
_ 5 n
poundL_ bull0
_ 5 n
mdash
bull mdash
mdash J jy^TRITIUM ADOlTlON bull mdash
2 2 bull II mdash
oraquo II ^ 10 G c
i s
pound 2 z tal Z I O
bull
0
bull bull
bull
A
bull bull bull
IIIIIJ 1 1
s 0
0 mdash
0 mdash
I 5 s
2
10deg
mdashb bull
e
a
e O
A A
A A
I 5 s
2
10deg A A aaw
i bull bull
s
2
bull -
bull i mdash
in- i 15 17 1raquo 21 23 25 27 29 Si
JULY OATCttTS
Fjj II Ofctcfvclaquo4 tnttvui cottt9MnHtottinCSTF 9ttn I
5
2
5
2 mdash
9
u 2 mdash
H = -S bull o u S 3
2 -
^ raquo mdash
5 h
2
bull0deg
raquo
2
mdash 1 1 1 1 1 1 1 1 = ~ O SALT (laquoCi l mdash bull 0FF-6ASVATCR SOLUBLE fcOA-i5) ^ mdash A OFF-CAS ELEMENTAL (f Citw5) mdash
^mm
a ^^ mdash^ 1 ltlaquo bull raquo I 1 1 4
^^ mdash 1 1
1 4 ~ trade
I bull mdash
bull
bull bull
I bull
I bull mdash I bull mdash
=
U
KITH KM A DOtT ON _
= bull
bull bull
llllll 1 1 1 1 V
bull
mdash
bullr T 0 ^
laquo bull 1 A A ~bull r^^ i S 0 O mdash mdash i S
A A ~~
0 0
e
51 A o = ^v 1 M M
mdash 4 A o-
mdash 1 -
bullbull i
T t If traquo bullraquo OATC MJtutT laquof7raquo
IT laquot 21
bull M M M ti cvrr MM i
7
tests The concentrations reported for the salt represent tritium in a chemically combined form since any eleshymental IfT trapped in the samples would have been reshyleased in preparing them for scintillation counting The tritium in the off-gis was present in two distinctly difshyferent cheriksl fonrr Part of the tritium activity was present in a water-soluble form implying a chemkil compound since HT does not interact significantly with water at room temperature The other form is presumed to be elemental HT since ft was trapped in water after passage of the sample stream through a bed of hot CuO
In all cases the results are presented in Figs 11 and 12 as reported with no corrections for apparent baseshyline concentrations However the results of samples taken before and after each test suggest that nonzero baseline concentrations were present The apparent baseline concentrations for the two experiments were
Itfexpcrineat Mcxatrineat
In uli 17 nCig I nCig In olT-cas elemental I pCicm1 I pOcm In off-jta water oiuMe I pCicm3 50 pCiere
During the tritium addition period for the first experishyment the tritium concentration in the salt (Fig I I open circles) increased almost linearly to a maximum of about 100 nCig and then decreased approximately exponentially over the following 3 to 4 days to its preshytest baseline concentration In the second experiment (Fig 12 open circles) the tritium concentration in the salt reached a maximum of 70 nCig and returned to the baseline concentration about 6 to 7 days later If baseshyline corrections are applied to the salt-sample data the apparent half-lives for tritium removal from the salt for the two experiments ar 92 and 12 hr respectively
If tritium removal from the salt is assumed to be a pure first-order process or combination of such procshyesses and if it is assumed that the processes were also active during the addition period the buildup of the tritium inventory in the salt (for a constant addition rate)should be described by
J M I O - i l l - bull ) X
where
V() tritium inventory in salt at any time I during che addition
A tritium addition rate
A lime constant for the removal process (or proc-esats)
I f several first-order processes were involved bull the intshyrant removal from the salt the time constant X would be the sum of the several individual time constants but the individual values would not be identifiable Substishytution of the actual addition rate into this equation gives the expected tritium inventory in the salt at any lime i f all of the tritium were reacting with the salt Conversely substitution of observed inventory values permits evaluation of the effective addition rate (the rate at which tritium did react with the salt) In either case the results may be expressed as ritium trapping efficiencies with values of 85 and 50 respectively for the two experiments These trapping efficiencies imply that significant quantities of the added material were reacting with and being trapped (at least temponriy) by the salt Data from the second experiment suggest the presence of other mechanisms with significantly longer time constants for removal of tritium from the salt Because of the apparent scatter in the data at longer times the extraction of these time constants was not attempted
The water-soluble tritium in the off-gas during the first experiment (Fig 11 closed circles) did not inshycrease significantly until after the injection was comshypleted and then rose to 1750 pCicm 3 The level then dropped rapidly to about 50 pCicm 3 rose again to about 300 pCicm 1 6S days after the addition and then decreased to lower values In the second experishyment the water-soluble tritium in the off-gas rose rapshyidly during the addition period and reached a maximum value at the end of the addition of 13100 pCicm 3 Abo the ratio of the concentration of water-soluble tritium in the off-gas to that of the elemental form was substantially greater in the second experiment than in the first
Owing to the apparent scatter in the data involving the water-soluble tritium in the off-gas for the first exshyperiment no quantitative evaluation was attempted However in the second test the initial decrease in conshycentration has an apparent half-life of 18 hr but the data again suggest the presence of other time constants An attempt was made to separate the time constants by assuming that the decay curve was made up A two simple first-order exponentials This led to apparent half-km of 9 J and 37 hr for the two processes Numershyical integration of the water-soluble tritium data for the second experiment yielded a total flow of 58 mCi through the off-gas line during the removal period and 75 mCi during the addition period Thus a total of 65 mti or about 65 of the tritium added is accounted for as combined tritium in the off-gas stream during this test Since the concentration of elemental tritium was
8
always less than 001 of the combined tritium concenshytration the presence of any elemental tritium does not significantly affect this observation
The concentration of elemental tritium in the off-gas samples rose during the addition phase of each experishyment 2nd apparently began to decrease as soon as the addition was stopped The maximum concentration in the first test was about 800 pCicm3 and only 40 pCicmJ in the second In both cases the decrease in concentration with time after the addition was too irregular to justify any quantitative evaluation
Although no measure of elemental tritium concentrashytion in the oalt a available a value can be inferred from the concentration in the off-gas by (1) assuming that the elemental tritium in the off-gas samples represents release from the salt and only from the salt and (2) assigning reasonable values to gas stripping parameters in the CSTF pump tank Concentrations of eiementai tritium calculated in this way indicate that the ratios of combinedelemental tritium in the salt were about 50 and 530 in the first and second experiments respecshytively It appears that chemical interactions between the tritium-containitg compound in the off-gas and the new metal of the sample line may have been responsible for the high concentrations of eiementai tritium in he off-gas samples from the first test and that the actual ratio of combinedelemental tritium in the salt may have been higher than 50
The inferred maximum concentration of elemental tritium in the salt during the second experiment is about 013 nCig Extension of the calculated tritium distribution with nominal metal-wall permeability (Table 12) to lower concentrations indicates that at 013 nCig tritium permeation through the loop walls could account for no more than about one-third of the tritium added to the system Since this is close to the amount not accounted for in the off-gas samples it appears that the effective permeability of the loop walls is near that of bare metal
12 XENON BEHAVIOR IN THE MSBR
GTMays
The computer program MSRXEP Woden-tali Rate-tot Xenon Poisoning) describing the X e behavior in the reference-design MSBR was used to perform calculashytions to study the effects of the Knudsen diffusion coefshyficient for xenon in the bulk graphite and graphite coatshying of the reactor core on the X e poison fraction The program has been described previously bull7
Following the fission of the fuel the decay of the mass-135 fission fragments is assumed to follow the decav chain shown below
l l
5 X e (1529 mm)
135 s C i J 135
(659 hr) Ba
(30 X 10 yr) (stable)
This diagram illustrates the half-life of each isotope and the branching ratio of the 3 5 1 decaying to 5 m X e and l 3 5 X e assumed for this study Along with this decay chain the following input data were used
Bubble concentration 44 bubbles per cubic centimeter of salt
Total helium dissolved in salt and present in gas bubshybles 10 X 10 molecm3
Bubble separator efficiency 907
For these conditions the mass transfer correlation in the program gives a bubble mass transfer coefficient of 00166 cmsec which leads to a loop-averaged void fracshytion of 055 with an average bubble diameter of 065 mm The calculated 3 f Xe poison fraction is 00046
The reference Knudsen diffusion coefficients for the bulk graphite and graphite coating associated with the 00046 poison fraction are 238 X 10 and 258 X 10 cm2sec respectively The bulk graphite values were varied from 258 X 10 to 258 X 10 cm1sec assuming no graphite coating was present (Table 13 cases I 3 5 7) to observe the effect on the poison fraction The low-permeability graphite coaling - 028 mm thick was assigned bulk-graphite values for the Knudsen diffusion coefficient and porosity making the coating part of the bulk graphite for calculation purshyposes Under these conditions the porosity of the bulk graphite was held constant at a value about 31 times
bullThe complete units for diffusion coefficient arc (cm ps) (sec bull cm graphite)
6 H A McLain el al in MSR Pmgrmn Semttmu front Rep Aug 31 1972 ORNM832pp If 13
7 H A McLam et at in MSR fmpwm Stmiumu Prop Rep Feb 29 1972 ORNL-47K2 pp |3 16 17
9
Kmfara M i a s m cocflkatat l c raquo p v laquo c -en graphite) CakabKlaquo1 Xe
DOHOB fractna M k f r a p a i K Graphite coati
CakabKlaquo1 Xe DOHOB fractna
1 258 x 10 Socoanag 00153 2 258 x 10 258 x 10 bull O0J52
3 258 x 10 No CiOMg 00140 4 258 x 10 bull 258 x 10 7 00I4S
5 258 x 10 bull Nocoatne 00113 258 x 10 bull 258 x 10 00107
7 258 x 10 No coalBaj 00077 8 258 x to bull 258 x 10 c 00044
M t graphite porosity ralae RKMH COHSUHI in ail cam 31 t met greater than rhe valar for ike graphite coating Refereraquoce valar for Hrfk graphite r Reference laquoalac for graphite coanag forma fraction for reference case
greater than that of the graphite coating In addition the Knudsen diffusion coefficient for the graphite coatshying was varied within the same aforementioned range while the diffusion coefficient of the bulk graphite was held constant at its reference value oi 258 X 10 cm 2sec to observe the effects on the poison fraction (cases 2 4 6 81 The previously stated values involving bubble characteristics and mass transfer were held conshystant throughout this series oi cakulalions
The results (Table I J | indicate that Knudsen diffushysion coefficient for the bulk graphite and graphite coalshying at least as low as the reference values (258 X 10 and 258 X 10 cm 1 sec ie case 8) would be reshyquired to meet the 0005 target value I gtr the X e poison fraction A diffusion coefficient of less than 258 X 10 cm 2sec would be required for the bulk graphshyite with no coaling became of its higher porosity If the permeability of the graphite coating did not yield a difshyfusion coefficient equal to that of the reference value such a coating would have little effect ltgtn xenon poisonshying The penalty for not coaling ihe graphite iraquo about OX)I in xenon poison fraction or 001 in breeding ratio if no attempt is nude to decrease the permeability or porosity of ihe base material
It may be noted in case 3 that a slight reduction in the Knudsen diffusion coefficient for ihe bulk graphite is
more effective in reducing the 5 X e poison fraction than a simitar reduction in the Knudsen diffusion coeffishycient for the graphite coating in case 4 In cases 6 and 8 where the permeability of the coating is very low reshyducing the Knudstn diffusion coefficient for the graphshyite coating affects the 5 X e poison fraction much more strongly
1 3 NEUTRON ANALYSIS
H T Kerr D 1_ Reed E J Allen
The neutronic analysis work during this reporting period has involved several tasks aimed at additional description of the neutronic characteristics of an MSBR and the provision of ncutronics information for the fueled in-reactor irradiation experiments
I JI MSIX Studies
Neutronic analysis studies for the reference-design MSBR are in progress in three areas
1 development of a two-dimensional neutronic comshyputational model of the MSBR using the computer code VENTURE and reestablishing the operabiliiy of a reactor optimization code (RODI
2 updating the neutron cross-section data bast used by various computer programs
3 calculation of the rate at which helium wii be proshyduced in the reactor vessel of the MSBR
A neutronic computational model o( Ihe MSBR using the computer code VENshyTURE is being developed VENTURE is a multishydimensional multigroup neutron diffusion computer code The MSBR model will have nine neutron energy groups and the ir-z geometry shown in Fig I J The various zones in the model allow for different core comshypositions and cress-section sets In addition to providing a check oi the design studies made with the ROD code using one-dimensional calculations this model will pershymit explicit evaluation of the nuclear reactivity effects associated with localized core periurbatiuii ltch as limited core voiding Previously such effects were conshyservatively estimated from calculations for an infinite medium of salt and graphite
bullhr pneffcv tuuHaniial reducifcMt in da Kmudm aWuaioa owflfcieat probatory wouhl be accompjaml by reduced po-roaiy
I T B r- ter 0 R Voady and G W ( unnmfham III irTlKf A CoaV mock for Sotriig Htipaup Stummk-ProNtwt Applying the Finite-Difference DiffmkmPieorv Appnaimntkm to Seutron Trmnpprt ORNL-SOamp2 tOvtohet 175raquo
9 II r Ramnann el al HOD A Sudew (md Fuel Cycle ImfSt-Mi Code for CmuUlmtFuel Rewclon ORNL-TM-3JS9
l September I 711
10
79-m7S
-a r
a-7
PERCENT THICKNESS 1 cm) ZONE NO FUEL SALT RADIAL AXIAL
1 CONTROL ROOS 172 2195 2 CORE )A 132 32 a 2195 3 CORE I A 132 500 2195 4 CORE I B 132 1195 2195 5 CORE n A ANO B 370 381 254 bull 9lR)^bV ^ W ^ ^ V v 1000 51 51 7 GRAPHITE REFL 10 7S2 aio bull SALT ANNULUS 1000 oa oa 9 REACTOR VESSEL 51 51
Fk 1 J Tw MMMH^OMI coMf bulltMtoMiMoMorNsm
11
ROD is a computer prccram for nuclear and fuel-cycle analyses of circulating-fuel reactors It consists essenshytially of a neutronks subprogram an equuibrium-conceniration subprogram and an optimization subproshygram Variables uch as breeding ratio fuel composition etc can be optimized with respect to cost
The operational status of the ROD code has been reshyestablished by running a telaquo case for the reference-design IOOO-MW(e) MSBR using the old cross-section data previously generated for the MSR program The test case will be rerun using the ENDFB-IV cross secshytions and any significant differences will be evaluated and reported
Generation of bullposted cross section data The necesshysary descriptive information for the neutronic model for use in the computer code VENTURE has been colshylected and the most recent ENDF1 cross-section data are needed (The neutron cross-section data used for MSBR analysis were originally derived from the GAM-H and ENDFB-I libraries with some ORNL modificashytions1 and no recent updates have been made) The new cross-section data are being obtained exclusively from the ENDFB-IV data Tiles using the AMPX processing system This effort will provide evaluated cross-section data and neutron energy spectra for typical regions of an MSBR and will serve as the data base for subsequent MSBR nuclear analyses The steps involved in this process are
1 Calculate 123-neutron-energy-group cross sections from the ENDFB-IV library The ENDF point data for 39 nuclides are weighted over an assumed energy spectrum to derive mulfigroup cross sections Thermal scattering cross sections are treated at 300 600900 and 1200 K for each nudide
2 Determine contributions to the multgroup cross secshytions from resolved resonances resonance self-shielding is treated for the various fuel configurashytions at 900 K
3 Perform fuel-moderator cell calculations for four geometries to adjust the cross sections for the flux depressions in regions having a high concentration of fuel or moderator (ceD homogenization calculashytions)
10 ENDFB-IV is ihe Evaluated Nuclear Data File-Vcnion IV and is the national reference set of evaluated cross-section data
11 O L SmithPreparation of 123 Group Matter Ctwt Secshytion Library for MSR Calculation ORNL-TM-4066 (March 1973)
12 N M Crane et al AMPX A Modular Code System for Generating Coupled Muttipoup Neutron-Gamma Ubraries from ENDFIB ORNL-TM-3706 J1974)
4 Perform a one-dunemional neutron transport calcushylation of the MSBR core to determine 123-group spectra and collapse the 123-group cross-section set to nine groups for each of the various zones in the model
5 Reorder the nine-group set from nudide ordering to group ordering the cross sections are then ready for use in VENTURE and ROD
The initial processing step is capable of treating nuclides in groups of from 1 to 3 depending upon the amount of data in the ENDFB-IV file for each nuclide This step is now complete for aD the nuclides of interest except 2 T h
Heauaa production bull reactor vessel The helium proshyduction in the reactor vessel for the present reference design and possible alternate designs will be estimated in conjunction with the neutronic modeling of the MSBR (Neutron energy spectra and flux magnitudes in the reactor vessel as obtained from the neutronic modd provide the bass for calculating helium production rates)
Helium is produced in nickel-base alloys primarily from these reactions
raquoNi raquo gt raquoNi raquo gt 5 Fe + 4 He
N i ^ L _ raquo F e laquo H e
degNi gt i 7 F e r 4 H e
The sNi(njt)and the degNi(ija) reactions are induced only by high-energy neutrons whereas the 5Ni(n7raquo and 5 Ni(laquoa) reactions are induced primarily by low-energy neutrons In highly thermalized neutron energy spectra as in the MSBR vessd the two-step reaction 5Ni(n7) $Ni(ffa) is the principal source of helium The 5 Ni cross sections are not wdl known but differshyential measurements are being made by ENDF particishypants1 Abo hdium analyses are available from several irradiated nickd specimens and effective integral cross sections wii be derived from these data for comparisons with the measured cross sections
At presen some cross-section information is available for the NHHJO) reaction Values for the 2200-msec (ix 00253-eV) cross section have been reported as 137 barns 4 and 18 barns It has also been reshyported1 3 that a large resonance occurs at 2039 cV with a total width V of 139 eV From this information a preliminary estimate of the shape and magnitude oi the
13 F C ferry Report to the US Sutiear Data Committee ORNL-TM-4SS5 (April 1975)
14 H M Eibnd el al Hud Sri poundltty 5) I I January 1974
12
cross section can be deduced and 123-group cross secshytions generated
From the Breit-Wigner one-level formula
where
A = constant A = neutron energy
tr = resonance energy (2039 cV) = total width (139 eV)
The constant K can be determined from the value of the cross section at 00253 eV which for this study is assumed to be either 137 or 18 hams Energy-dependent cross sections can be generated and the helium production can then be estimated with te folshylowing equation
-V H eltraquolraquoraquoraquoilaquoraquoJ - bull bull )
X 1 - e x p ( - o e 0 1 o
- [I exp ( -OJ IDI OJ I
where o ( = (17) cross section of s Ni Oj = absorption cross section of s N i Oj = (na) cross section of N i A1 - initial s N i concentration
9 = neutron flux = time
V|| e(0 = helium concentration at time t
IJ2 Analysis of TeGenE-r-raquoiments
Fission rates and tellurium production rates for the fuel pins in the TeCen-l irradiation experiment were reported in the preceding MSR semiannual report The fission rates were estimated by a flux mapping experiment direct flux monitoring of the TeGen-l capshysule and computations analyses The tellurium concenshytrations in the fuel pins were calculated from these fisshysion rates but no estimates for the accuracy of the calculated tellurium concentrations were given in the report
The accuracy of the 2 3 U fission product yield data 1 6 leads to an estimated uncertainty for the yield of tellurium in the TeGen-l capsule of about 135 Assuming that the uncertainty in the estimated fission rates is plusmn15 the uncertainly in the reported tellurium concentrations is about 20
The TeGen-2 experimental capsule is scheduled to be inserted nto the ORR for irradiation in October I97S Flux monitors will be loaded into the capsule prior to the capsules insertion into the ORR After the TeGen-2 capsule is removed from the reactor the monitors will be recovered and their induced activities measured to develop estimates of the tellurium production rates for TeGen-2
14 HIGH-TEMPERATURE DESIGN METHODS
GTYahr
Thermal ratchetttng and creep-fatigue damage are important considerations in the structural design of high-temperature reactor systems Simplified analytical methods in ASME Code Case IS92 (ref 17) and RDT Standard F9-4T (ref 18) permit the assessment of ratchetting and creep-fatigue damage on the basis of elastic-analysis results provided 1 number of restrictive conditions are met Otherwise detailed inelastic analyshyses which are usually quite expensive for the conditions where they are currently necessary are required to show that code requirements are iet Analytical investishygations to extend the range over which simplified ratchshyetting and creep-fatigue rules may be used to show compliance with code requirements are being performed under the ORNL High-Temperature Structural Design Program which is supported in part by the MSRP Modeling procedures for applying the simplified ratchet-ting rules to geometries and loadings prototypic of those encountered in LMFBR component designs are to be identified Then trie conservative applicability of these ratcnetting rules and procedures and of elastic creep-fatigue rules will be demonstrated and placed on a reasonably sound and defensible engineering basis Finally an assessment will be made of the applicability of the simplified design methods to Hasteiloy N under MSBK design conditions and the importance of thermal ratchetling in an MSBR will be determined
S II T Kerr and F J Allen in MSR Program Semiannu Pnrfr Rep Feb A 1975 ORNL-5047pp M 15
16 M F Meek and B F Rider Compilation of Fission Product Yields Vallecilos Suclear Onter 1974 General Elec-ric Company NFDO-I2I54-I (January 26 1974)
17 Code Caw 1592 Interpretations of ASMF Boiler and Prejre Vessel Ctde American Society ltbull( Mechanical Fni-neerv New York 1974
18 KDT Standard F9-4T Requirements flt Construction of Suclear System Components at Elevated Temperatures (Suppleshyment to ASMF Code Cases I$92 1593 1594 1595 and I5VA) September 1974
13
The detailed plans for achieving the stated objectives were given in a previous progress report The basic approach is to perform a relatively small number of carefully planned and coordinated rigorous dastic-plastic-creep ratchetting-type analyses of the geometries illustrated in Fig 14 Each geometry is subjected to the axial bending thermal transient and pressure loadings described in Table 131 of ref 19 Structural problems I and 2 are being analyzed at ORNL using the PLACRE computer program 2 0 while problems 3 and 4 are being analyzed by Atomics International and Comshybustion Engineering respectively using the MARC comshyputer program1 Each inelastic analysis will include a complete code evaluation for accumulated strains and creep-fatigue damage Also ssociated with each inshy
elastic analysis are a number of elastic analyses to proshyvide the input parameters required to apply the various simplified ratchetting rules and procedures and elastic creep-fatigue noes The progress to date on these studies is discussed below
Both Al and CE have encountered difficulties in their three-dimensional inelastic analyses Although consider-
19 J M Comm and G T Yabr in MSR Program Semmtmu Progr Rep Feb 28 1975 ORNL-5047 pp 15-22
20 W K Saitory Fiirte Element Pnfnm Documentashytion High-Tempertnre Sintctmwl DrsnM Methods for LMFBR Components Quart Prop Rep Dec SI 1971 ORNL-TM-3736 p 66
21 MARC-CDC developed by MARC Analysis Research Corporation Providence Rl
-YV^ - NOTOCD CTLMMCM SHELLS TYPE 3 N0ZZLE-1D-9PHQMN
OftNl OWC 75 76S
SMELL
JUNCTION OETAS (TYPES 341
76i0 X ilaquo75 WML
TYPE 2- cnjomctL awns
Q-omdash -T-QlaquoO -Q0
) AT AT I (bull) STEPPED MMLTHKKNESS (k) UNFClaquoM WILL WTH
OFFERENTUL MTOCTTNG
TYPE 4- nomz-m-crurvmcM SHELL flHXMLET NOZZLE)
1 6 0 0 X0375 WALL
-TS IO X 1675 WALL
(O IMFODM VMU MTH (ABULT-M CYUNOEP AXIAL TEMPERATl J VWaATCN
Fij 14 Slnicturai crmfiguraiinns used in the analytical invatqplion of the applicability of simplified nlchetling and crrcp-faligiie rule
14
able effort has gone into developing fmite-elemeni models that are of a size that can be accommodated on presrnt-day computers and into improving the MARC computer program the large 3-D inelastic analyses are proving considerably more expensive to run than had been expected
The experience at AI and CE indicates the importance of developing amplified methods of analysis Three-dimensional inelastic analysis of many realistic comshyponent geometries is too expensive and time consuming at present to be used routinely Although developments in computers and stress analysis programs may bring the cost down in the future it is desirable meanwhile to mminuze die number of inelastic analyses that must be done
141 GrcutarCyundricai Shells
Nine cases of circular cylindrical shells luve been proshyposed for bulllaquo present study Two of the cases involve notched shells The other seven cases involve axial variashytions in temperature pressure andor wall thickness or a bunt-in wall All nine cases were to be analyzed using the ORNL in-house finite-element program PLACRE
A ten-cyde inelastic analysis and a one-cycle elastic analyras have now been completed for all nine cases Both thr inelastic and the elastic results for all nine cases have been completely poKprocessed
Because of modifications to the creep-fatigue damage rules presently under study by the ASME Boiler and Pressure Vessel Code Working Group on CreepFatigue it may be necessary to modify the ORNL postprocessor and repeal some of the postprocessing to keep the present study up to date
142 Nozzle-to-Spherical Sfcenf
After some difficulties the MARC computer code a operational on the IBM computer at the Rockwell Intershynational Western Computing Center and check cases have demonstrated that this code will perform satisfacshytorily
Considerable effort has gone into developing the finite-element model of the nozzle-to-sphcricai shell An isoparametric three-dimensional 20-node brick eleshyment will be used (o model the entire geometry Beshycause of symmetry about the plane of the applied moment only half of the nozzle-to-spherical shel has to be modeled There are raquoix 30deg-wide dements around
bullWork jlt ORNL by W K Sartory Work raquobull Atomics International by Y S Pn
the half-model There are three elements through the wall at the root section of the nozzle and only one element through the wall in both the nozzle and the sphere away from the intersection region
A series of elastic analyses must be done since this is a thermal stress problem in which temperature varies with time Since the moment applied to the nozzL is the only nonaxtsymmetric load the principle of supershyposition will be used to reduce the cost of the elastic analyses A series of axisymmetrk analyses were done to determine the stresses due to the internal pressure and temperature and one three-dimensional analysis was done to determine the stresses due to the moment applied to the nozzle The stresses from the three-dimensional analysis will be added to the stresses from the axisymmetric analyses to obtain the total elastic stresses
The axisymmetric model in the elastic analyses was used to determine what maximum thermal load increshyment may be employed without having to do an excesshysive number of iterations during each increment On this basis the first ryele of the three-dimensional inelastic analysis was divided into 32 increments The first three increments of the three-dimensional inelastic analysis have been completed The computer cost for these three increments was higher than anticipated Efforts wiQ be made to find some way to reduce the cost to an acceptshyable level
14J Nozzte-toCyindeT Intersection
The original concept for the inelastic ratchet ting-type analysis of the nozzle-to-cylinder intersection was to perform two separate analyses (I) a thin-shell analysis of the whole structure ami (2) a detailed three-dimensional solid analysis of the intersection only Disshyplacements and forces to be applied at the boundaries of the three-dimensional solid model of the intersection were to be determined from the shell model at the end of each loading increment The total computer time of the two analyses would be less than that required for the solution of the problem using one model of the complete nozzle-to-cylinder intersection with suffishyciently small elements in the intersection region Howshyever the transfer of the forces and deflections from the shell analysis to the three-dimensional solid analysis was found to be more difficult than anticipated Because the shell element and solid element have differtit displaceshyment functions a special constraint must be imposed on the shell elements at the boundaries of the three-dimensional solid model to assure compatibility This
bullWork at Combustion Engineering by R S Barsoum
15
stiffens the intersection in the shell model When runshyning the initial elastic analyses it was found that small changes in the displacement boundary conditions applied to the solid model would produce large changes in the results of the analysis- From a pragmatic viewshypoint the biggest difficulty with the two-model method is assuring that the correct data are transferred from the shell analysis to the solid analysis at every increment in loading
Due to the above considerations it was decided to do the analysis by using only one model made up of a combination of a reduced integration shell element and a 20-node solid element which are fully compatible with each other
It was necessary to restructure a large portion of the MARC program to perform the inelastic analysis for the
3-D nvdel of the nozzle-to-cylinder intersection This restructuring made a larger core available for the analyshys t The restructuring involved stripping unnccded porshytions of the program putting common space on low-cost storage and eliminating mesh optimization and its correspondence table
The inelastic analysis of the nozzle-to-cylinder intershysection was started The full pressure and nozzle-moment loadings were imposed on the structure which resulted in stresses less than 0936 of the yield stress at 870 K ( I 00degF) When the first increment of thermal load was applied convergence was not obtained because of an error in the computer program which is being corrected
2 Systems and Components Development R H Guymon
21 GASSYSTEMS TECHNOLOGY FACILITY
RHGugtmon GTMays
After a brief shutdown at the beginning of this repottshying period to modify running clearances in the pan water operation of the Gas-Systems Technology Faculty (GSTF) was resumed on March II 1975 with the bypass loop blanked (Fig 21 gt Considerably larger salt-pump shaft oscmatious were encountered than before the labyrinth clearances were increased1 After obtainshying calibration data for the main-loop variable-flow reshystricts and for the salt pump at low flows the ioor was shut down to install the bypass loop variable-flow re-slrictor Water testing was then resumed on April 14 and continued throughout the period
Data for calibration on the bypass loop variable-flow rcstrictor and for the salt pump were obtained At normal pump speed the head-capacity performance of the installed imprDer was v W below the nominal loop design conditions At the nominal liquid flow rate and pressure drop in the main loop the flow rates from the gas outlets of the bubble separator were satisfactory Although loop cavitation (as indicated by wise level) was reduced by replacing the variable-flow restrictors with orifices the amplitude of the salt-pump shaft oscilshylations was not reduced appreciably Prdirmnary infor-
I R H Gaymoa MJ V R Haadty JUSK ABVW Stmt-mm Anjr Rep Feb 291975 ORKL-507pp 23 25
shows that leakage past the salt-pump shaft labyrinth is higher than desirable and attempts wfti be made to reduce thts
Tests under actual operating conditions with water in the loop indicated that the densitometer war be sttsfac-tory for salt operation IVelinwuary information obshytained fiom saturating the loop water with air and then stripping the air by injecting hehum at the bubble genershyator indicated the need for moniioring the oxygen conshycentration in the off-gas from the bunt salt separator in the off-gas from the salt pump in the loop water and perhaps in the water in the pump tank Dtitkuhies were also encountered with the response lime of the oxygen monitors and with the reprodudbiity of their readings
Data on the salt-pump shaft deflections and oscara-tions obtained during the previous period indicated that the running clearances at the labyrinth (fountain flow area I and at the impeuer hub should be increased to prevent contact of the metal surfaces during operashytion with salt (Fig 22) After increasing the clearances water operation was restarted with the bypass loop Hanked off The shaft oscillations were much larger than they had been previously under similar conditions Turbulence or cavitation as indicated by noise was the apparent cause For more flexibility in (Renting condishytions the bypass-loop variable-flow restrictor was inshystalled Loop parameters were then recorded at many
cwmmo
Flaquoj 21 GB4VMWM Facaw
16
17
n$ J J csrf w raquoNVJgt
coaibinaiiotts of lalt-pump speed and settings of the mam loop and hypass4oop variable-flow lestriciorv
Lug-log plots were nude of pressure drops across various sections of the loop as functions of the flow rates through the segments Ssnce the head loss for a fixed resistance is proportional to a fixed power of the fluid velocity the cams should be straight lines unless the character of the resistance changes due to cavitashytion The pSots indicated that cavitation was occurring in the main loo between the inlet to the nauvloop variable-flow restricior f FE-l02A)and the throat oi the bubble generator at flow rates above 320 gpm (1200 liters mm I with the variable-flow resiriclor set at I in (25 mm I above 470 gpm with the variable-flow reslric-tor at 2 in (100 litersmin at 51 mml above 600 gpm with the variable-flow restricior at 3 in (2300 btersmin at 76 mml and above 630 gpm with the variable-flow resthctor at 4 in (2400 litersmin at 102 mml The data were not sufficiently precise to determine whether cavishytation was also occurring in the bypass loop however noise indicated thai it was
Since the loop turbulence andor cavitation as indishycated by noise and the salt-pump shaft escalations were unacceptable at conditions required by the bubble separator design changes were made in the main-loop and bypass-loop flow restrictions By replacing each vamMe-flow restrictor with two or more orifices in series the loop noise level was decreased but there was
little or no decrease in the aaphtwdr- of the a f t oscd-btions
The amptitaae of the shaft ascafetsoas was plotted as a wactiua of salt pump speed at various operating a laquo -dMMis (Fuj 23| At salt-pump speeds less than about 1600 rpm the oscantioas were reasonably smaM and ai any given speed appeared to be unaffected by (11 flow rates between 450 aad 1 0 ) gpmlt 1700 to 4000 liters n a n M 2 ) salt-pump overpre wares between 5 and iSpsig ( I J X 10 to 2D X 10 Pal ( 3 | type of restneuon (variaafc flow restnetors orifices or a coiahmaiion ot these I or 14) flow roate (through the main loop bypass loop or both) At higher speeds the osdaatioa ampit-twe mcreased rapidly with mcieasts in speed and there was mote scatter in the data making it difficult to evalshyuate improvement in cavitation and effects of other variables However at any given speed above about 1700 rpm mcreasmg the flow rate (between 450 and 1050gpm)caused larger oscanuoas
One puaablf explanation for the increased amplitude of the osculations at higher speeds b thai the shaft is approaching its critical vibration frequency and is theiraquo-fore more sensitive to disturbances such as loop turbushylence or carnation The critical speed of this impeller assembly is 220 rpm in an which would indicate a maximum normal operating speed of 1710 rpru using bullhe normal industrial practice ot operating pumps at less than 75^ of critical speed
If the pump shaft osculations were in fact a conshysequence of operation near the critical speed ot the rotating assembly two obvious alternatives were availshyable to reduce the amplitude of the oscuHaiions
1 further reduction of the loop disturbances to minishymize the driving forces that cause oscillation
2 operation at lower speeds to reduce the osolatorv response to disturbances
The first alternative was rejected because it would have required extensive modification of the loop and it was difficult to guarantee that all sources of such disturbshyances could be reduced to satisfactory levels Design cakidaiiofls showed that the desired flow and head (3800 litersmin at 3 0 3 m or 1000 gpm at 100 f u could be obtained by replacing the present 11 Virt-diam (2ftgtnun) impeter with a l3-tn-dam (330-mail unit and operating it at 1500 rpm A larger impeller is being machined from an available HastcHoy N rough casting Since the larger impeller will be somewhat heavier than the original one it win cause a reduction in the critical speed of the rotating assembly The estimated critical speed with the new impeller is 2000 rpm which makes the operating speed 757 of the critical speed
18
n-va
I
bull
bull 4SO-C4V laquo bull TOTM run
bull bull80-KM9 laquo bull TOTH FLOW bull t
bull bull
bull
bull bull bull bull bull bull
bull bull bull bull m bull m bull
r- i bull gt
bull bull bull bull - bull jr bullbull r laquo bull 1
bull laquooo ooo rsoo i4oo CMO
SALT n w SPCEO t fraquo) lt7oo laquoaoo
Flaquo2J GSTFpanpAtfia
At a few off-design conditions during some of the bter runs the pump shaft deflection records showed random spikes in one direction superimposed on the relatively uniform oscillations described earlier These occurred with higher than normal flow rates in the main loop or at reduced system overpressure Since eidter increasing the overpressure or injecting gas at the bubble generator reduced or eliminated these random oscillashytions it was concluded that they were a consequence of cavitation at the bubble generator Such cavitation and the attendant oscillations are not expected to occur at normal operating conditions
212 Sak-Twnw f i i f i inmdash u DMa and CaKbration of the Variable-Flow Ratricton
The original design of the CSTF provided for varying the salt-pump speed andor changing the variable-flow restrict or settings to obtain different flow rates or presshy
sures needed for future experiments However instrushymentation will not be provided for measuring the bypass-loop flow rate during salt operation and only urn salt pressure measuring devices will be installed I at the salt-pump discharge and at the bubble-separator disshycharge) Also since the salt pump was modified and has a mismatched impeller-volute combination no perforshymance data were available Therefore extra pressure indicators were installed for the water tests and loop pressure profiles were obtained at various pump speeds flow rales and variable-flow restricior settings to evalushyate the pump peiformance
The calibration of the main-loop variaMe-flow restric-tor and of the salt pump at low flow rales was straightshyforward since with the bypass loop blanked off the total pump flow was measured directly by the main-loop vert tun However once the bypass-loop variable-flow restrictor was installed the calibration of it and
19
the pump was complicated Hie main-loop variable-flow restriciof was closed and the bypass-loop variable-flow rest net or was calibrated at low flow laies using the pump calibration curves established before it was inshystalled The mam-loop variable-flow restrictor was then opened to various settings and the pump calibration curves were extended by adding the measured flow through the mam loop to the flow through the bypass loop taken from the bypass-loop variable-flow reslnctor calibration curves Then using these extended head-capaciiy curves for the pump it was possible to extend the calibration curves to higher flows
The pump calibration curves (Fig 241 indicate that at 1770 rpm the pump flow rate wiB be 970 gpm 13700 litersmm) at 100 ft 1305 ml of head The ongnul design called for 500 gpm (1900 litersmmgt through each loop however the bypass flow rate can be reduced to 470 gpm (1800 liters mm) without compromtsng any of the objectives
To determine the main-loop variable-flow restrictor selling for normal operation with a flow rale of 500 gpm in the mam loop plots were made of the pump head vs flow for several settings of the flew restrict or From these a curve was made of pump head at 500 gpm (1900 litersmm) vs settings (Fig 25) A 185-m (47-mm) setting wril give the desired head of 100 ft (305 m) at 500 gpm
m - K B i
lt M M laquolaquo IFC-I02M SCTTWG FOraquo 300 laquo bull Zr-MSS laquo bull C-laquo4AJ
SpoundTTlaquoVS FOM0laquoB ^ Str-MSS vlaquoMFt-laquoolaquoi
si TlaquoK ran 47olaquopraquo
1 2 3 4 VMIASLC FLOS EST^CTO SCTTI
s
FraquoZ5
bull40 bull n-vw
C O shy
CO
l
CO bull
40 1
20 f
o 200 400 M O n o ltooo woo FUMIlaquoOTI
Fit- bullbull Hcai capacity curves for oV GSTF y mdash gt bull
The bypass variable-flow reslnctor settings were detershymined similarly 7 -I found to be 1-85 in (47 mm) at 500 gpm (lltHXgt liters mm) or 170 in (43 mm) at 470 gpm (IK00 liter v mm)
21 J Satt-Pmnp Fountain Flow
The GSTF salt pump is a centrifugal sump pump having an impeller which rotates in a volute section which in turn is located in a pump bowl The clearance between the impeller and the volute assembly at the pump inlet allows leakage from the discharge directly (o the pump suction (see Fig 22) A second bypass flow called the fountain flow escapes through the clearances between the impeller shaft and the volute assembly This bypass stream flows into the pump bowl circulates downward and reenters the main stream at the pump suction Due to the large liquid holdup and large surface area in the pump bowl significant gas-liquid mass transshyfer can occur in the fountain flow stream and herefore its flow rale is important in analyzing mas transfer processes in the loop Since the fountain Pow is not measured directly a method using mass balances on
20
measured gas flows was developed to determute thn flow rale
A lump J-parameter mcjel of the GSTF was used to develop equations Iron which an express lor ike rounfam flow was dented The system model contain two major regions the pump bowl and the primary loop Imnn and bypass segmental cutmstmg ai a fas seciion and a liquid section tach section was assumed to be perfectly mued The three enteral time-dependent equations lor a specific p s m i gas mixture are given m Tabic 21 representing gas mas balances for the pumrbowi gas section the pump-bowl tinwd section and the primary-loop f seciwn Icuculating oidsraquo
These were simplified by applying the folowmg
1 There is no gas carry-under in the pump bowl which implies that Ugt the efficiency for separation of bobshybles from the fountain flow Ut a unity and Ft -Ffi bull | + Afs-gthe bwbWe surface area m the pump howl M I the void fraction in the pump bowl frgtngt and the concentration of gas m the pump bowl (Clt I are nonappbcable or zero
2 Mass transfer equtJibnurn nasts in the primary loop which implies that the mass transfer term - j(C 4 -KRTCi )a zero
3 Steady-stale conditions exist making all time derivashytives zero
4 Ff = 0 since there was no gas purge flow during the experiments
Therefore Eq (3) Table 21 reduces to
FB FfL ltlaquo = 0 Ml Solving f o r +
By adding Eqs (1) and (2) Table 21 and simplifying
FjyenLCgtFfi +1C+FBSCX
FC Ff( rtC1FBSCJ=0 16)
By substituting Eq (5) into Eq (6) Ff may be exshypressed in terms of a quadratic equation
ltC C 2 I F bull KQi Fbdquo FBSKCt C 2 )
FgCt FCtFf
QttlF8SltC C raquo F C | 0 (7gt
Equation (7) is a general solution for the fountain flow which depends upon the gas concentrations in
each ol the three sections of the model It it is assumed that man transfer equAbmm exists at the galaquoltiugtd interlace in the pump jowl the gas conceniciuon in the pump bowl liquid | ( I is relaied to the correspondmg concentration m the pump bowl gas section tCt I raquoy Henrys law If only one gas rs involved (eg heliumK C toNows directly from the pump buwl overpressure Further since mass transfer equuawium was assumed for the primary loop ihe gas ctmcentralion m the kiop liquid (for a smgk gas) ioifews from the loop average pressure and Henry s law Thus the foil am ikm magt be evahsalaquoed from fcq |7raquo using orker known liquid flow rates and measurable gas flow rales into and owl ol the system If no mass transfer is assumed to occm~ at the gas liquid mterface m the pump bowl thr gas conshycentration m the hqmd leaving the pump bowl is the same as thai in the cmtiiug liquid lue O = C I and Eq(7i reduces to
^=IFgCyFCi I ^
Since the rate oi mass transfer m the pump bond is neither minute nor zero Eq I 7 I ni l give a low indftca-tion and Eq (X| laquo i give a high indication of the founshytain flow rate The deviation from the actual fountain flow rate win depend on how much mass transfer actushyally occurs m any experimeni If the loop void fraction is increased (by increasing the gas input rate I the conshytribution of mass transfer across the gas-liquid interface to ihe flow rate of gas laquo-ji of the pump bowl wif be reduced relative to the bubble contribution Therefore a pkn of the calculated iountam flow vs Ihe reciprocal of the gas input rate at several different conditions should give the actual fountain flow rale when extrashypolated to zero (infinite gas flow rate) usmg either Eq (7raquoor(8gt
The preceding equations and approach were used to calculate the fountain How for the GSTF pump Results from ihe plot indicated thai the curves generated were not defined wen enough to provide accurately the reshyquired extrapolations The range of fountain flows at the highest gas input rate at which data were obtained was 100 to 200 gpm (30 to 760 litersmmraquo
Even the lower estimated value for the fountain flow may excessively complicate future mass transfer experishyments so efforts will be made to reduce this flow Since ihe labyrinth clearances cannot be reduced without incurring meial-io-metal contact between the pump shaft and the volute hack vanes will be installed on the lop of ihe impeller lo minimize the differential pressure which drives the fountain flow
Iihfc 21 (iiimiuhaUmimpjallnntfitf timtpulalfcinmiMHof (iVI
KllO til illlll|tkltil |tl pill|K lllllilllis scpHlUil IMIlaquo IfMIKU nl t in nl oil Kii iiivkiilnl ill llnw ill bull limn liiiiiilini bull iliraquoraquonluil |Mgt lt mw ^JVIIHIII pinup linlaquol III yis gt|iui Him lH|iil(lniv inliHir pump Imwl
lltpi l n I lt f lt bull bull bull laquo lt laquo laquo laquo raquo laquo iff
Kllgt ill tlltllllr lllgtMi|vraquoll bullMl itlsMllVCll IV 11111 lllllslll 111111 ILIIKUM lllraquoraquolaquogtlVlaquol |l ni ittN iimMim |HiMiii in pii-witi m ni ltlin|tiil ut ilimlraquoilaquol pivwiii in iligtlaquo ilhvilvcilin liKnimiiK liuinlim llutt limn IMlaquo A I raquo laquo IM in Iniltlil trnm pump innn| Iiwl ln|iml illaquo lnihlltKIIIIIII hi|iiiil initligt in |iiini|lt linul biwl in lu|i
IH (11 Imlt vill
laquoltplllln| Kpiitiui I bull(raquo bull raquo I US gt laquo A K U i IHIl gt raquobull raquol IyjM
raquo i
KiMniil ihmvn iluw nl ilntt nl hiililiUv n u n luinl t i IIIIIIIIIOMII iliMmUinl raquoM ImhNiivinuwit bull I Civ linnillnH igtilaquo in Itmi pump Imwl I IIISSIIMII IIUIIIIIH ill lninliin In IMIMIII
III limp mill IHIIIIIU bull Inlnnp bull (ligt bull IliMJo llim llnlaquo w p j u l m llflltLllnl l l l l n i i | i
l i p u i m i I bulllaquo bull gt laquo l laquo IKH gtill M raquo O 1 raquo
22
214 The void fraction of the liquid after it leaves the I
Me separator n u n be known in ordrr to evaluate the bubble separator efficiency Densitometer mstrumenta-IWB (unwf a digital voltmeter for readout was mrtalrd at the loop and tesu were uumr using 0 3 0 0 ( 1 1 X 0 z dnsecl i raquo T a ece The effccu of void fraction were shambled by inserting pontic sheets 3 and 6 nms |0J07copy and 0152 mmi thick between the
detector and by using the mrtamc shim side m m k n steel cahVratioa plates 10 to 250
mis (0254 to 6 J 5 mm) thick which were designed for rhraquo purpose
The nail cncounteied dming dealupmtnt testing uras stal peestnt The hourly drift would be equivalent to a
efficiency of shorn 10 a h operation (assuming a void fraction of 0J
at the - c ^^hMe separator) Thus short-term tesraquoi wnl be required to ntmnunt the bdbbk jcparaior efficiencies
bullused on densitometer readings the bubble-separator efficiency was greater than 98 at various operating conauuons with water whkh it shghtty predtcted
Ft Ft
Fraquos
Ft
A -
of liquid gar interface m pump bowl bubble surface area in puop bowl bubble surface area in loop gas concentration in pump bowl gas space gas concentration sn pumn bowl hauid gas concentration in the loop bubbles gas concentration in loop liquid gts concentration m pump bowl bubbles gas concentration in gas purge entering the pump bowl gas space flow of total off-fas from pump bowl gas fltow rate to bubble generator nqiad flow from bubble separator via the bum salt separator to the pump bowl (assume no bubshybles) fountain flow (liquid and buboto) flow of gas purge into pump bowl gas space flow of liquid and bubbles from pwnp bowl to loop mass transfer coefficient for gas dissolved in pump bowl liquid to gas space in pump bowl mass transfer coefficient for gas dissolved u pump bowl liquid to bubbles in pump bowl mass transfer coefficient for dissolved gas in loop liquid lo bubbles in loop liquid
K Henrys lr~ (solubility) coefficient Q flow of bruid and buttles to bubble separator A universal gas constant r temperature
V laquo total gas volume in pump bowl V2 mlumt of wquuland bubbles m pump bowl VL = volume of drcubnutt liquid and bubbles i
loop c ( bubble separator efficiency tf efficiency for separation of bubbles from founshy
tain Aow bull t z void fraction in loop fluid
ltbullgt void fraction m pump bowl flutd
2-2 COOLAKt-SALTnamOUXX FACaUTYKSfF)
A N Sunt
Modifications to the sak coM trap (SCT) were com 1 and the loop was started up on March 14 and operated for 1279 hr to check the effcetrve-|975
of the sail titer to obtain data on salt different operating condrtmws
off-gas sample dau m preparation Work was completed on design
and checkout of the trita the tritium test
generation rates and to obtain salt and for the tritium tests fabrication addition system started At the end of the report period two tritium additions had been completed aad plans were being made for additional tririum addition tests as well as tests designed to examine how the tritium behavior is affected by the infection of steam into the sail
221 Laap Opossum
The SCT flow tnes were disconnected from the sysshytem and the loop was started up on March I 1975 The loop operated continuously until May 6 1975 when it was shut down to permit insinuation of otnp-ment in the containment enclosure for the tritium tests The loop was started again on June 271975 and it was saB in operation at the end of the report period when more than 2500 hr of operating tune had been togged without pHajgmg in the off-gas tine This is convincing evidence that the salt nust filter has been effective since the off-gas Ime had piuggct after only 240 hr of operashytion before the nasi fdier was instated
The loop is operating at a pump speed of 1790 rpm (estimated salt flow rate 54 literssec) and a pump bowl
2 A N San MS 2$ 1975 OKNL-50t7t 25
J IMttI
Avar Rrp Frb
23
praquo overpressure ol 2hi X IU5 Pa (20G0 mm 1 absi The pump bowl oit-^u flow which consuls ui helium coniammg a tew percent of BF prm trace quantities ol condenuMe material is about 2 litervmm iSTPl- The BF i concentration ltraquoi the oil-gas rraquo a tuncnon ol the bull1-1 partial pressure in the tail which in lurn raquo a strong unction in the tail lemprfaiuie txcept Im short period raquoi lime when special tests required a different retime the valt circulating tempetature haraquo beet mauv lamcd ai 535 lo 540 ( at which pomt the BF concenshytration in she oli-ga dream is about 25r by volume The loop otf-garaquo stream emepf tor a 100-cm1 turn wmpk gti ream iv paued through a 72(cuht iraptdry ice alcohol bath | Material which is a dtn while toiid ai itap temperature and a dirty brawn ilmd upon warmshying to room temperaiuie and which is rich m tnimm (about 1(1 nO el continue ilaquogt collect m the cold trap at a rale laquogtt I igt lOngcm (STPlotKff-ga Thnmaie-iial rraquo believed lo be a variable mixture who- compos-lion depends on the relative partial pressures ol BF HFand H Ooser the salt (see Sect 41i
A ol 000 on Auguvt 31 Ilaquo75 the bullop had accushymulated 3073 hr ol sail circulating tune smce being reactivated in Decembei |raquo74
222 Salt Mat Test
Bemeen March 25 Ilaquoraquo75and April 24 Iraquo75 a series ot icsigt wj run lo determine ihe concent ration ot wit
t m the off-fas stream as a runctwu ot a l t tempera-lure aad BF flow for each lest the loop operating coadaioas were set at the desired values ami the off-fas stream was shunted through a metamc 5- to deg-m (iter whKh was inserted mto the ait-sample access nozzle on the pump howl The sal mat concentration was calcushylated usmg the fan m weight of the filler aad the total flow sf fas A total of tea teas were earned out The test tune was nnrmatty about 12 to 15 hi but in two cases it was shortened tc about 3 hr because at the buildup ot a high-preawiie drop acroa the fdter Pump bowl pressure was 2Jb7 X 10 Pa and total off-gas flow was 1 litervmm (STP| When BF was added to the helium entering the pump bowl the BF flow was ad-msted raquo (bat the BF partial pressure m the mcomuig gas was the same as tFe calculated psttial pressure of the BF over the salt asswmng the eutectic mixture ot NaBFlaquo acd aF The salt drcutatiag temperature was controlled at either 535 or 620degC The observed conshycern rations ol mtst m the off-gas (Table 22) ranged Irom MOO ng on ai the loner temperature ibdquo as mgh agt 500 ng cm 1 al the higher temperature At the lower temperature where the expected partial pressure of BF in the sail raquoalaquo low the addition of BF with the cover gas was ineffective m reducing the amount ot ~ist in the off-gas At the hajtter temperature Hugher BF
P 27
23 CSTTi 175
VJ St Bt rcmrvrjrurr ijpampr rtlaquoraquo
t gt prepare iraquom mmSTPgt bull mm tic
raquo
Sjir imit iltgtikrgturjiraquogtn IIK Jr o n laquorr if-jtni
2fraquo |ltraquoS
raquo 25laquogt
5
Ifco
Klt-tft Zgt
5 5-532
bulltnrrlaquoflr 4Vlt
H
ion
Avrufr laquoi
11 i KX
KvrisfX 15
Vtumi^r Ih niKviic bull HtipgtltJium
24
partial pressure in the salt) a significant reduction was observed in the mist concentration when i lFj was added with the cover gas However it was not reduced to as low a value as at the lower temperature These results whie not completely definitive suggest that bull F evolution from the salt may no be the only mrst-producing mechanism in the pump tank that is simple mechanical agitation of the salt in the pomp bowl may abo produce some mist In addition no data were obshytained with excess BFj concentrations m the cowr gas Since the mstaflatioR of the salt-rust iHter in the off gas line was effective in eiumnating the operational probshylems in the CSTF caused K v the mist further investigashytions of methods to lirnii or control the mist have been deferred m favor of experiments to study tritium beshyhavior in the system
The decision to use tritium rather than deuterium a a test gas4 in the CSTF necessitated additional design effort and a somewhat more elaborate test setup in order to satisfy apubcaMe radiation safety require-meats A conceptual design was prepared for he tritium addition system and a preimnnary radiation safety analysis was performed for the proposed test Engineershy
ing design procurement fabrication and msiaBauon of the tritium addition system were completed by the third week m June 1975- The addition tube and the addition procedure for tritium are essenttaly the same as those devised for the addition of deuterium The rwer tube of the addition assembly is pressurized with hydr-jgen contanung a small amount of tritium and the gas is avowed to diffuse through the Hastefloy N tube which loom the lower end of the addition tube and which is immersed in the flowing salt stream (see Fig 2oraquo The HasteSoy N lube is 120 mm long by 127 mm in OD by 106 mm m ID and provision p made to fasten metanurped specimens to the upstream faje The portion of the addition tube inunedntely adjacent to the HasteRoy N section is surrounded by an evacushyated annuius monitored to check for extraneous tritium leakage The hydrogen-tritium mixture is passed through a purifier (M-Ag tube) to remove impurities such u O Ngt and H G which might interfere with the permeation process The probe volume ~p (infecshytion tube plus adjacent tubing) and a calmrated refershyence volume are interconnected and pressurized with the H - T mixture at the start of the test The two volumes are then isolated trom each other whne the addition rs in progress At the end of the addition
-Owe 75-T2CW
TRITIUM TRANSFER CYLMOER
4 0 0 C
sect laquo r 2^
1 SAMPLE
VACUUM ltS)
ampQ- ]
HYDROGEN
VACUUM ANNULUS
INJECTION TU8E
|StT2
35-C
lOO-C
FLOW 532laquoCi
Fig 2 T w mdash aUthnm ygtw far CiSTF
25
period the difference m pressure between p and V is recorded then the two volumes are equdibrated and the final equilibrium pressure is recorded The initial and fwal pressures ir lppx and pz respectively the foul equilibrium pressure p and the known volume and temperature ot lgt are then used to calculate the amount ot fas which pernxated the addition probe according to the equation
laquogt PiPi Pi V bdquo = _ x ^ try Pzraquo PT
where n is (rK number oi moles ltgti gas transferred R is the molar gas constant Tr is the reference volume temshyperature and the other symbols are as previously deshyfined
During the addition the amount oi extraneous leakshyage i calculated from pressure rise measurements in the evacuated annulus and this quantity is subtracted trom n to obtain the net amount oi gas iransierred into ihe salt The tntium content ot the hydrogen-tritium mixshyture is determined by mass spectrometer anaksu and Ihe net amount ot added tritium is then caicuiated
Tritium land hydrogen) which enters the salt stream rs assumed either to rematR in the sail laquo iraquo leave ihe sail by one ot two paths eiiher hy permeation through the walls ltgtl ihe loop piping or by irartsler to the gas phase in ihe pump howl or in the sail monitoring vessel iSMYl and leaving the loop raquoih the oii-gas stream During and ailer ar addition the tritium conieni ot the sail is monshyitored b lakmg samples raquot salt trom ie sail pool n ihe pump bowl or in ihe SMV and ihe irmum content oi ihe oil-gas stream ts rrhMMored hv takiru sampics from he oii-gas line ai a point ahoul I m downstream bullgt ihe rramp bowl The oil-gas sample stream is pasted first through a water trap to collect chemicaiiy ^gtmh-neltl I water-slaquo M unlet tmium and then through an oxidizing atmosphere to convert eiemeniai iriiium io iniiaied water raquohkh is c-iliecled in a seciid irap The tritium conieni oi the salt samples and ltraquoi hoih ihlt oil-gas samples are determined hy a scintillation cHinimg techshynique During the iniiul tritium addition experiments no provision was made IlaquoH measuring loop wait petnva-lion so lhat ihe tritium lost hy this mechanism is assumed |o he Ihe ditferenlaquoe hefwven the arnouni of Iniiiim aided and ihe sum oi the quantities w-hich ieave in ihe oii-gas stream and which remain in the sail
firing the March 14 Igt~v | 4 y |ltrgt bdquopei almg period a number of sail and off-gas samples were taken fo obtain baseline raquoaJues |o minim concenira-lion and lo shake down and evaluate the sampling tech-ii-ities During sluiidown oi lthe CSTI- in Magt and June
Iraquo75 the intium addunn probe was msiaUed in the survediance-spei-onen access tube and the final installashytion work was done on the tnUum addition system A stainless steel valve (HV-255AI and some stainless steel tubing which were part of the original off-gas sample-line installation were removed and replaced with a Mood valve and Hastelloy N tubing because it was ieii that the Monti and HasteUoy N would be less likely to react with the off-gas sample stream Two 2-5-cm-diam X 45-cm-long KastelkA N lubes were filled with sail from the dram tank and set aside as representative samples oi the salt as it existed prior to the start oi the tntium tesis-
On June Z~ I~5 the mop was filled and salt cirvuia-tion was resumed Several additions o i hydrogen raquoere made to check out the operation of the addition system aid to obtan data on permtaiior rates A loul or bull J cm M f l oi hydrogen was added in ihese rest and the last addition lt raquol an STPraquo was made -gtn July Jfs Ilaquoraquo~5 with ihe addition tube pressuried to I_gt~ X It) Pa the measured permeation rale was about laquo cm hi ipared with a predicted value i raquo era hr The Iirsl addition o iriiium was made on July l~ i _ 5 and a second addition with CiHlditmns essenziaili he same as iraquor the fust additnm was made August 5 1 _ 5 In each case sail and oii-gas samples were taken during ihe tritium ad Inigtft lahoui 10 hri and or atgtraquou 2 weeks afterward until sample resuiis indicated Tf at the intium levels had returned io iheu pretest values or had Mahihed Oaia lot calculatufi o ch-e amount o addej ps are sin win in Tabic _ A maihemaiica analysis and discuss of ihe tampie results are presented in Se^ i i
TaMr 2J Jtwtmm JMIIPO 4U far CSTI rnf
f rr runilv-r 1 i lraquojrc ~ ~y s r
ti4iilaquon vijrTrJ i raquo bullxt ltMiri-n erxteJ - gt lt o -gti VMiTfcltn -aw bullgt t N bull Im-ijS p-i-uir^ TjiTa i s j r bull bull bull 1 raquoUl prcraquoMraquorf p~ ltti bullraquo laquo bull r - t |utftt -nm p-riu-r r f^i a bull laquobull 1 bull 1 r v-jirrlt- m i i gt i i
fr Tcmr^r 4u-r k bull laquo lt l l bullbull ltrr gt rv-Tltjriraquor - r m -raquo raquo i 1 bull bull raquolt--laquo-f i e j l -j -lt- rn bullbulllt raquo raquo 14
i--tTWjTl-raquon - J 7T1 bull - raquo bull bull gt |TTti-n -raquonltf n TilaquoT in nisfi ii bull bull bull
ra^ pr^i l--l i m u M e i laquo m i it it X bull bull
1 bullbull J irmm j dea bull ml 11 raquolt bull
26
2 J FORCEftCONVECTlON LOOPS
W R Huntley M D Silverman H fc Robertson
The Forced-Convection Corrosion Loop Program is part of the effort to develop a satisfactory structural alloy for molten-salt reactors Corrosion loop MSR-FCL-2b is operating with reference fuel salt at typical MSBR velocities and temperature gradients to evaluate the corrosion and mass transfer o( standard Kistelloy N Addition of tellurium to the salt in MSR-FCL-2b i olanned after baseline corrosion data ire obtained in me absence of tellurium At this time the loop has operated approximately 3000 hr at design ST conditions with the expected low corrosion rates
Two additional corrosion loop facilities designated -ISR-FCL 3 and MSR-FCL4 are being constructed They arc being fabricated of 2T titanium-modified Hastelloy N alloy which is expected to be more represhysentative of the final material of construction for an MSBR than standard Hastelloy N
2 JI Operation of MSR-FCL-2b
Loop FCL-2b was operated continuously for about 3000 hr from February to June lraquo75 unuer design ST (565degC minimum 70SdegC maximum)conditions During this period standard Hastelloy N corrosion specimens installed in the loop in January 1975 were exposed to circulating fuel salt at three different temperatures (565 635 and 705degC) As expected corrosion rates were low the highest value was 01 mil year Ojimyear) at the highest temperature station
Salt samples taken at intervals have been analyzed for major constituents metallic impurities and oxygen (Table 24) Except for an occasional high value for oxygen or iron the analyses are relatively consistent and indicate that the observed corrosion processes have had very little effect on the concentrations of the various species present in the fuel salt Analytical probe readings for the VIU ratio indicative of the redox condition of the salt have been taken on a weekly basis This ratio which wraquo about 7 X I0 3 at the beginning of the corrosion run rapidly dropped to about I X | 0 3
after the first 24 hr of operation The ratio then gradushyally fell to A I X I0 1 by the end of March CVI500 hr elapsed time) and it has remained at that level during the latter part of the operation
After the corrosion specimens were removed for the 3000-hr weight-change measurements preparations wei nude for obtaining htat transfer data on the Li-Be-Th-U fuel salt (717-16-12-93 mole ) At this
time a Calrod electric tubular heater failure was disshycovered on the pipe line (i 27-mm-OD X 11-aim-wall) which runs from metallurgical station No 3 to the inlet of cooler No I After removing the thermal insulation about 10 to 20 cm 3 of salt was found on the loop piping and the bumed-out heater Grainy material was present on the heater sheath at three locations directly opposite peeled-off sections of oxide layer on the Hastelloy N piping A small crack (A 5 mm long) was found on a tubing bend directly under the failed heater Whether the heater arced causing the piping to fail or whether the salt leak from the loop caused the healer burnout is uncertain at this time Examination of specishymens from these regions is continuing
The fuel salt was drained from the loop into the fill-and-drain tank after the leak was discovered Analytical results on a sample taken from the tank indicated that no obvious contamination of the fuel salt had occurred A new section oi tradeping was installed (approximately 24 m from metallurgical station No 3 to the inlet to cooler No I) During the shutdown several defective thermocouples and two defective dam-shell electric heaters were replaced Ball valves were refurbished numerous small repairs were made and instruments were recalibrated After the thermal insulation had heen replaced baseline heat loss measurements were made with no salt in the loop in preparation for taking heat transfer data The loop was ready for refilling at the end of aly approximately four weeks after the salt leak was discovered After filling the loop heat transfer measurements were obtained with flowing salt The ALPHA pump speed was varied from 1000 to 4600 rpm resulting in salt flows of approximately 27 to 16 litersmin which correspond to Reynolds numbers that vary from 1600 to 14000 The lower limit for salt flow was set to prevent freezing and the upper limit was dictated by the power required foi driving the pump At the lowest flow rate unusual wall temperature profiles were noted which probably were caused by entrance conditions and transitional flow effects The heat transshyfer measurements were completed near the end of this reporting period and analysis of the data is in progress
The stringers containing the Hastelloy N corrosion specimens were reinserted in the loop and ST operashytion (S65degC minimum 705degC maximum) was resumed in order to complete the originally planned 4000-hr corshyrosion run If no unusual corrosion behavior is encounshytered in the next 1000 hr of operation nickel fluoride (NiFj) additions will be made to the loop in order to raise the oxidation potential of the salt to a level correshysponding to a U^U3 ratio of about I0 3 and a new set of corrosion specimens will be exposed
27
raw t u si tioalaquolaquofcUF-laquofF -ThF-UFlaquo
i-im
Sanpfe Mo
Date impkd (197$)
Total hoars of a i l
arcabboa bullhel saatptcd
Major coapoMMs TIJCC ameiub Notes
Sanpfe Mo
Date impkd (197$)
Total hoars of a i l
arcabboa bullhel saatptcd Li Be Tb U F Fe a f t O C S
lb 1-17 0 78 221 43-2 I I I 467 101 40 23 lt50 I I 99 Flash salt 2b 1-23 48 60 42 52 3b 128 0 799 174 430 an 463 75 70 15 125 29 4 3 New sail 4b 2-11 177 137 63 60 75 Sb 2 18 355 154 64 68 45 6b 2-24 498 98 63 28 48 7b 3-3 676 7 8 236 4 2 J 105 463 147 67 35 45 23 17 bullb 3-25 1146 7UI 255 430 104 458 256 59 57 lt2S 14 9 9b 4 16 1647 816 229 432 097 452 $ 70 30 20 78 15
10b 5-12 2197 829 264 430 103 455 62 85 30 60 l i b 6 4 238 823 225 427 100 445 30 70 25 140 12b 6-23 3173 820 208 433 104 451 35 75 25 152 13b 7-3 3177 830 218 430 10 452 70 80 40 30 FaVaaa-dran
oak Mb 8-7 3246 728 203 454) 100 450 45 85 70 58
7|7-16-i2-03 mole bull
232 Desia Mid CoastnKtkm of FCL-3 raquossrfFCL4
The design work for FCL-3 and FCL-4 was essentially completed any changes or revisions which occur during construction of FCL-3 will also be made on FCL-4
The piping support frame for FCL-3 was installed and installation of electrical equipment is proceeding- Conshyduit lines have been fin from the variable-speed motor-generator set on the ground floor up to the electrical rack installed on the experiment floor and a sizable
number of transformers starters switches etc have been installed The instrument panel cabinets have been positioned and cable trays are now being installed Fabrication of two ALPHA-pump rotary elements and two pump bowls is 90 complete A large number of completed items for both loops (eg dump tanks auxilshyiary pump tanks cooler housings blower-duct assemshyblies electric drive motors purge gas cabinets etc-) are on hand awaiting installation Fabrication of the titanium-modified IrasteHoy N tubing for the salt piping of the loop is in progress
Pan 2 Chemistry
L M Ferris
Chemical research and devdopmen rdated to the design and ultima^ operation oraquo MSBKs are itill conshycentrated on fuel- and coolant-salt chemistry and the devdopment of analytical methods tV-r use in these systems-
Studies of the chemistry of tellurium in fuel salt have continued to aid in elucidating the role of this dement in the interranular cracking of Hascdioy N and related alloys An important initial phase of this work involves ihe preparation of the pure tellurides Li Te and LiTe3
for use in solubility measurements loop experiments clectroanaiytical studies and studies of tellurium redox behavior in molten salts Technique for preparing these idlurides have been developed and experimental quanshytities have been prepared Spectroscopic studies of tdlu-rium chemisfy in m-jlten salts and of the equilibrium H(ggt + UF 4 |d) = UKj(d) + HF(ggt have also been
initiated In work using molten chloride solvents at Lust tvo light-absorbing tellurium species have beei shown in be present These species are as yet unidentishyfied but have compositions in the range Li2Te to LiTe4 Preliminary values of the quotients for the above equilibrium have been obtained using LiBeF4 as the solvent These values are in reasonable agreement with those obtained previously by other workers
A packed-bed electrode of glassy carbon spheres was constructed calibrated with Cd1 ions and used in experiments with Hi1 ions in LiCI-KCI eutectic It was concluded that this electrode was prototypic of orie (hat could be used for the electroanalysis or electrolytic removal of bismuth oxide and other species in MSBR fuel salt Preliminary experiments were also conducted lo evaluate some questions relating raquoo the mixing of fuel
and coolant salts The results suggest ihat or mixing small amounts oV coolant salt with large amounts of fuel sal the rate of evolution of BFj gas will not be intolershyably high and that somj oxide can be present in the coolant salt without effecting precipitation of L0 or ThO - Lattice enthalpies of first-row transition metal fluorider were calculated to provide a theoretical basis for evaluating thermochemical data gtr svructural-metal fluorides
Work on several aspects of coolani-sait chemistry has continued Analyses of condensates from the Coolant-Salt Technology Facility (CSTF) indicate that the vapor above (he salt is a mixture of simple gases such as BFj HF and H 0 rather than a single molecular compound Tritium concentrates in the condensates by about a factor of 10 s relative to the salt Studies of the system NaF-NaBF 4-B 0 at 400 to 600degC show that at least two oxygen-containing species aie present in typical coolant salt One species is Na B F 6 0 j while the other has not yet belaquon identified
The development of analytical methods for both fuel and coolant salt was also continued An in-line voltam-metric method was used to monitor U^U 1 ratios in two thermal-convection and one forced-circulation loops Two additions of tritium were made at the CSTF The salt in the loop did significantly retain tritium and the tritium ultimately appeared in the off-gas Work was begun on using various electrodes for determining iron in MSBR fuel salt Previous work had been conducted with solvents that did not contain thorium Preliminary voltammetric experiments were conducted to identify soluble electroactive tellurium species in MSBR fuel salt
28
3L Fuc-J-Scik Chcmism
ADKeimers
31 COMPOUNDS IN THE LITHIUM-TELLURIUM SYSTEM
D Y Va^ntine A D Keimers
It has beei k-mcns rated that tellurium vapor can induce shallow grain-boundary attack in Hasiefloy N similar to that observed on the surfaces of the fuel-salt circuit of the MSRE However the actual oxidation state or states in which teilunum is present in MSBR fuel salt an LiF-BeF-ThF4-UFlaquo mixture and the chemical reactions with the Hastelloy N surfaces remain to be determined The lithium-tellurium system is being investigated to determine which Li-Te species can be present and to synthesize samples of all possible lithium tetlurides- The solubility of these compounds in the fuel salt will then be determined In addition they will be used in spectrophotometry- and electrochemical investishygations of tellurium species in melts
During this report period sample of LijTe and LiTe
were prepared The preparations were made in an argon-atmosphere vacuum box equipped with an enshyclosed evacuated heater which held a molybdenum crucible All handling of Li-Te compounds was done in inert-atmosphere boxes sometimes the compounds were sealed under vacuum to minimize oxygen nitroshygen or H 0 contamination Lithium having an oxygen content of ltI00 ppm was supplied by the Materials Compatibility Laboratory Metals 2nd Ceramics Divishysion Tellurium metal of 99999 wt Tr purity was obtained from Alpha Ventron Products
The Li2Te was first prepared by dropping small pieces of lithium into molten ellunum contained in a molybshydenum crucible at 550degC The reaction was extremely exothermic emitting fumes and light tlashes after each lithium addition Solid formation occurred at lower lithium concentrations than expected from the reported phase diagram2 Further lithium additions continued 10 be absorbed after first melting on the surface of the solid phase An amount of lithium necessary to satisfy Ihe Li2Tc si gtichiomeiry was taken up in this manner However because of the loss of vapor and of some solid material which splashed out of the crucible during the early additions of liihium it is doubtful that the stoichi-omclry was in fact preserved
The x-ray diffraction pattern showed a single phase identified as LijTc having a face-centered cubic strucshy
ture with a lattice parameter of 65119 t OJ0O0Z A J
The oxygen contamination in the product totaled about 375 ppm- Spectrographs analysis reported 0-5 wt ~ molybdenum present Since the oxygen level and moshylybdenum impurities were fairly low a larger-scale prepshyaration wts attempted as well as a direct preparation of LiTcj by the same method In both cases rv product was contaminated unacceptabiy with molybdenum and these preparations were discarded Apparently the first preparation had affected the surface of the crucible such that the reaction with molybdenum was accelershyated in these subsequent experiments
The molybdenum crucible was used for one further preparation after cleaning and polishing the inside surshyface The Li Te was prepared from the lithium-rich side of the phase diagram by dropping tellurium info molten lithium Since molybdenum is relatively inert toward lithium4 less reaction with the crucible was expected In addition this preparation could be made at a much lower temperature The tellurium was added to the lithium in small increments with the temperature held at 250degC Each of the first additions resulted in a smooth quiet reaction with a solid phase forming on the bottom of the crucible However since completion of the reaction was not visibly apparent the temperashyture of the system was increased above the tellurium melting point to about 550degC to ensure that unreacted tellurium was not on the bottom of the crucible More additions of tellurium were then made Above 500degC a popping noise was heard after each addition of tellushyrium After about three-fourths of the tellurium had besn added the system was mostly solid As more tellushyrium was added the amount of solid in the system became so great that further additions of tellurium were
I A D Keimers and D Y Valentin MSR Program Semi atmu Profr Rep f-eh ltlt 1975 ORNL-5047p 40
3 P T Cunningham S A Johnson and F i Cairns Vlectrmhem Soc Klrcirochrm Set Tech 120328(1973)
3 X-ray lattice parameters were measured by O B Cavin of the Metals and Ceramics Division The value 65119 00002 A measured tor IiTe is in agreement with the value 6SI7 A reported by K Ziml A Harden and B Dauth Hlektrochem 40 588 11934) The value 61620 bull 00002 A measured for LiTe is in agreement with the value 6162 A reported in ref 2
4 H W leavenworlh and R F CUaryAcu Mel 9519 11961)
29
30
not covered by the liquid Subsequent additions proshyduced light flashes and poppng associated with the highly exotherrmc reaction as encountered m the preshyvious preparations oi Li Te FuuBy enough additional tellurium was added to the sgt-stem to satisfy the Li Te stoictuonietry and the system was aflowed to cool to room temperature
Upon crushing the cooled product fow differently colored substances were distinguishable gray opaque material wine-red to pink opaque material colorless translucent crystals and metafile tellurium Analyses were performer separately on each type of material
1 Gray opaque material The x-ray diffraction pattern revealed LigtTe and LiTe no other lines were present The oxygen level was about 218 pom Specshytrograph analysts indicated the presence of about 01 w t molybdenum
2 Red-hue material Only a few crystals of all-red material could be isolated The remainder of the red-hue material was ground together with some surshyrounding gray material The x-ray diffraction pattern corresponded mainly to Li2Te A small amount of LiTe was also preset The oxygen content was reported to be about 275 ppm Spectrograph analysis reported lt00I wt 9 molybdenum
3 Colorless translucent nd isolated red crystals Both these products gave an -ay diffraction pattern corresponding to pure Lij Te with no indication of a second phase
To ensure a uniform product all the various colored materials were recombined and thoroughly mixed The LijTe mixture was then placed in a 2-in-diam tungsten boat which had previously been enclosed in a quartz bottle The quartz bottle was then evacuated sealed and heated to 550degC for about 16 hr The product obtained after cooling was almost completely cream-white However when the bottle was broken open the product began to turn beige upon exposure to the envishyronment of the inert-atmosphere box The product was then crushed roughly and placed in sample bottles On standing in the bottles the product gradually reverted to the red-gray color it had been before the heat treatshyment with the exception that the product in one bottle remained beige The reason for the lack of uniform behavior is as yet unknown Some of the darkened product was returned to the tungsten boat in another quartz bottle and (he heat treatment repealed it again turned the cream-white color The products both the light beige and the red-gray color forms gave x-ray difshyfraction patterns for a single phase LijTe Analysis of this LijTe is given in Table 31
T l r 3 J ABMywafU-TcaaJliTc
UU t i l r
l l lVI 1 laquo 5 - MI 1 - bullbull It IWI ~ raquo raquo - bullbull 5 Sraquo 4 r II 5
Li TV IMgt4T I mj r i LiTe bullbulln4r ~ bull 14- 05 XI lt - 5 raquo Innh4r ~ l ITI - 1511
-fjgt diftraciMi SMctcpfc SWfJr rhue 0ypm ipeani 740lltr l 275tMrri
MatyMtmdash i w i 005 ltlaquoraquo0I
T w p m iwt i lt00l lt 0 laquo l
Red-gray Li2Te was mixed with the amount o( tellushyrium required to satisfy the LiTe stoiduometry The mixture was then sealed in a qurtz bottle under vacuum and heated to 550degC for 2 hr The not liquid was dark metallic gray On cooling the solid appeared bright silver-gray The x-ray diffraction pattern conshyfirmed the presence of a single phase LiTe having a near body-centered cubic structure with a pscdo-ell lattice parameter of 61620 plusmn 0D002 A J The well-exposed Debye-Scherrer diffraction patterns suggest that the structure of this compound is more complex than previously reported2 Work will continue in an effort to describe this structure The oxygen content was reported to be 275 ppm Spectrographs analysis reported no molybdenum or tungsten contamination Analysis of this LiTe3 is also given in Table 31
3 2 SPECTROSCOPY OF TELLURIUM SPECIES IN MOLTEN SALTS
B F Hitch L M Toth
A spectroscopic investigation of tellurium behavior in molten salts has been initiated to identify the species present in solution and to obtain thermodynamic data which will permit the determination of the species redox behavior in MSBR fuel salt A previous investigashytion 1 had indicated that Te~ is present in LiF-BeFj (66-34 mole ) on the basis of an absorption band occurring at 478 nm when LiTe was the -Jded solute however the work wai terminated before these observashytions had been fully substantiated The current work is an extension of those earlier measurements which
5 C K Bamberger i P Young and R G ROM Inorg Suel Chtm 36115raquo U974)
31
should lead ultimately to a measurement ol redox equishylibria such as
LiTe bull H bull 5LJF = 3Li2Te bull 5HF II)
^Te bull LiF + ^ H = LiTe + HF 1
These data should then permit the prediction of teilu-num redox chemistry as a function oi LF gt l T F 4 ratio
During the past several months most ot the effort was devoted to assembly oi the apparatus necessary for the fluoride measurements Ths involved fabrication and assembly- ot the following furnace for the fluoride studies diamond-windov ed specirophotometrk cells a vacuum and inert gas system and a KHF saturator through which H is passed to generate HF-H mixtures of known proportions
Also during the period of preparation some attention was given to a supporting study in chloride melts The advantages of working in chlorides are
i previous ground-work investigations have already been reported7
2 chlorides are easier to hold in silica cells without container corrosion
3 the greater solubility oi the tellundes in chlorides may reveal greater detail because oi more intense spectra
Atsorption spectra have been measured for LiTo LiTej and tellurium solutes as well as during titrations of LijTe with Tej in the LiCTKCl eutectic 31 450 to 700degC These data indicate that at least two light-absorbing species are present in molten chlorides conshytaining lithium tellurides with compositions in the range LiTe to LiTe4 Furthermore an examination of Te 2 in the LCl-KCI eutectic has indicated thai there is a second species present besides Te which is formed at high temperatures andor high halide ion activity More detailed experiments are anticipated using purer lithium lelluride solutes in the diamond-windowed cell to demonstrate (hat (he additional species are not related to impurities from the reagent or silica corrosion
6 This work has done in cooperation with J Bryncsfad of I he Metals and Ceramics Division
7 I) M Cruen R I McBclh M S I osier and ( Y (roulhiimcl Phys Otcm 70i2t472 (l6gt
3 J URANIUM TOTRAFLUOftDE-HYMOGEN EQUIUHUUM IN MOLTEN FLUORIDE SOLUTIONS
L O Gilpatnck L M Toth
The equilibrium
LF 4ldraquo4H2lg) = UF J ldraquoHF|g) HI
is under investigation using improved methods of analyshyses and control The effects of temperature and solvent composition changes on the equilibrium quotient
Q = rraquo
are the immediate objectives of this work and are sought to resolve previous discrepancies noted in fuel-sal redox behavior
The procedure involves sparging a small (approxishymately 1 gl sample of salt solution (UF 4 concentration of 0038 to 013 mole liter or 0065 to 022 mole rgt) with H gas at 5S0 to 850degC until partial reduction of UF 4 to UF 3 is observed HF is added to oxidize the desired amount of LF j back to UF 4 When an equilibshyrium between the HF H gas mixture and the UF 3 -UF 4
in solution is reached a spectrophotometric determinashytion of the UFj and UF 4 concentrations is made These data are combined with the analytically determined HF(H2) ratio to obtain the equilibrium quotient at a given set of conditions
The assembly of the system for this experiment has been completed and measurements of equilibrium quotients using LiK-BeF (66-34 mole ^) as the solshyvent have been initiated Some delay has occurred because of trace water in the HFHj sparge gas which was responsible for the hydrolysis of uranium tetra-fluoride and the subsequent precipitation of 1 0 The problem has been partially alleviated by treatment of the KHF saturator gas supply lines and spectrophotoshymetry furnace with fluorine at room temperature Howshyever back diffusion of water vapor into the furnace from the exit gas line has also caused substantial solute losses and has been reduced by using higher HF-H2 flow
This research in support of the MSBR Program was funded by the KRDA Division of Physical Research
H I O Gilpaimk and L M Toth The Uranium Tetrafluoridc Hydrogen Fquilihnum in Mollcn Fluoride Solushytions MSR Pnygram Srmunnu Progr Rep Feh u 7 s ORNI-5rt47p43
32
rates Together these modifications have reduced the totute Kisses to an acceptable level (2^ per day i
Equilibrium has been achieved at 650X lor measured I F VFj ratios of approximately 02 X IG to X 10- Although the I F VF 4 values are reproducible a fixed KHF saturator temperatures the aaalyiicaily detennined HF values are not as yet Consequently the standard error (approximately 50lt) in the equilibrium quotients is soil rather high So tar a value ofQplusmn 10 has been determined at 650degC which compares favorshyably with the previous value of 116 X I 0 T Most of the immediate effort is being Jevoted to improving the precision of the HF determination
Tritium control in an MSBR would be favored by higher equilibrium quotients In an MSBR the I F UF 4 ratio will probably be fixed by equilibria involving the structural metals The tritium inventory will be established by the tritium production rate and the various tritium removal processes UQ is larger than previously anticipated the partial pressure of HF would be higher and the partial pressure of H would be lower than previously estimated Thus TH would be available at a lower concentration for permeation through the heal exchanger to contaminate the coolant loop (and ultimately the steam system) and a larger proportion of the tritium would be present as TF which would be removed in the helium gas stream
34 POROUS ELECTRODE STUDIES IN MOLTEN SALTS
H R Bronstein F A Posey
Work continued on development of porous and packed-bed electrode systems as continuous on-line monitors of the concentrations of electroactive subshystances especially dissolved bismuth in MSBR fuel salt In previous w o r k 1 0 a prototype parked-bed elecshytrode of glassy carbon spheres (MOO microns in dishyameter) was tested in the LiCI-lCCI eutectic system Linear-sweep voltammetric measurements carried out in the presence of small amounts of iron and cadmium salts showed that the cell instrumentation and auxilshyiary systems functioned successfully and demonstrated
9 G Long and F F Blankenship The Ftahiliiy of Uranium Triflimhde ORNL-TM-2065 Part II (November 1969) p 16 Kq 6 with xjyt - 0002
H H R Bronstein and F A Posey MSR Program Semi-anmi Progr fP raquolaquo Jl 1974 ORNL-5011 pp 49 51
II H R Bronsleir and F A Posey HSR Pro-am Semi-anmi Progr Rep reh 2H IV7S ORNL-5047 p 44
the sensitivity of this method of analysts However these measurements showed the need tot redesign oi the experimental assembly to permit removal and replaceshyment of the cell and addition of substances to the melt
During this report period the redesigned packed-bed electrode of glassy carbon spheres was tested again in LiCI-KCI (5SJMIJ mote ) eutectic since the beshyhavior of a number of electroactive substances has alshyready been established in this medium The packed bed of glassy carbon spheres was supported on a porous quartz frit and contained in a quartz sheath Another porous quartz frit pressed on the bed from above A glassy carbon rod penetrated the upper quartz frit to provide compaction cf the bed ana electrical contact with a long standee steel rod which was insulated from the surrounding tantalum support tube The oiectrode assembly was dipped into the melt so that the molten salt flowed up through the interior oi the bed and out an overflow dot By this means il was possible to obtain a reproducible volume of melt inside the packed-bed electrode
Voitairmetric and coUometric scans of the pure melt at 3raquo5degC showed that the background current was small A typical set of current-potential and charge-pountiai background curves is shown in Fig 31 - A 2-V
1 1 I flmdashImdashTmdashImdashraquomdashbull 1mdash T I mdash T 1 1 T mdashi 1 I I bull 1 l - laquo 0 0
to 0 5 0 0 -OS 10 IS ELECTKOOC P0TpoundlraquoTiraquoi ( n bull laquolaquoamp) (raquobull$)
Ffc 31 Linear-sweep voUMimetry and coalonef ry of cadshymium in LCI-KCI (588-412 mole gt eutcctic with a packed-bed electrode of glassy caboa spheres Curve A current backshyground (sweep rate = 10 mVsec) curve B current with Cd present (sweep rate = 5 mVsec) curve C background charging curve (sweep rale - if) mVsec) curve D charging curve with (d present (sweep rate = 5 mVsec)
33
range ot electrode potential could be swept without evidence of significant amounts ot ouduable or reducshyible impurities in the meli For calibration purposes a known quantity ot -radmium ions lCdgt was added to the melt lraquoy anodiation ol molten cadmium metal conshytained in a specially designed graphite cup which could he lowered into the melt The amount ot cadmium adod (Fig 311 was monitored by use oran electronic autorancui couometer
Following addition ol cadmium the voifammeinc and coulometric scans indicated that only a small fraction ol the known cadi-uum content inside the void space oi the packed-bed electrode was being measured- After removal of the cell assembly examination showed flat the glassy carbon contact rod had somehow fractured possibly due to excessive pressure from the matin stainless steel contact rod and resumed in lo of elecshytrical contact with the packe-i-Sed electrod
The -ell assembly was then redesigned and rebuilt to permit electrical contact to be maintained without undue pressure and to allow accurate measurement of the working volume of the packed-bed electrode The new design was similar to that of the previous cell except that the upper fritted quartz disk was permashynently sealed (o the surrounding quart sheath A small hole in (he center of the disk permitted loading of the daisy carbon spheres into the electrode assembly and provided accurate positioning of the glassy carbon con-act rod into ihe bed Prior to loading of the spheres
the volume contained between the porous quart disks was measured with mercury
Some voltammetric and coulometric scans in the presshyence oi cadmium ions are shown in Fig- 3 1 As in preshyvious studies in aqueous media with the packed-bed electrode2 more accurate analytical results were obtained on Ihe anodic half cycle (stripping) than on bulli cathodic half cycle (deposition) Approximately 40 mC of cadmium was estimated to be within the packed-bed electrode The coulometric results shown in Fig 31 n quite consistent with this value Thus it is possible knowing the geometry raquof a packed-bed electrode to estimate the response and sensitivity within reasonable limits (the accuracy oi estimation depends upon void fraction the accuracy of the volume measurement and other factors) Repeated scans over a period of many days showed good reproducibility and also established that diffusion through the quart frits during the time of measurement (only a few minuus) has very little effect on the results
12 I I R Bronstcin and I- A Posey Otrm Mr Amu Proxr Rep May raquo IW ORiSI 4976 pp 1119 I I
Another cell was pocked with jOOp-dum glassy carbon spheres and used to obtain the results shown m Fig 32- In this case a quantity of amp ions had been anodued into the melt in a manner ssraiar to that used for cadmium- At the time of these measurements the same melt had been in use for many weeks Fig 32 shows voiiammetnc and couloroetric anodic stripping curves in the vicinity ot the anodic peak for stripping oi bismuth which had previously been deposited on the imemal surfaces of the electrode during the cathodic ^ii cycle In agreement with observations of others we found that volatility of BiCl precluded close correshyspondence between added and observed quantities of bismuth and that the bismuth peak decreased steadily with time The appearance of the bismuth peak suggests that possibly some alloying of bismuth with the cadshymium look place
Other expeiiments on bismuth reduction and stripshyping will be carried out in the future in which cadmium used for calibration of the ceil sysreni is absent In addition the present apparatus wiL be used lto study the electrochemistry oi lithium teiluride in the UC1-KC1 euieciic Observations on lb tellurium system in the chloride melt may be useful in interpretation of tellushyrium behavior in later studies with MSBR fuel salt The
CWV-3WG 75 -Z99
TEMPERATURE 392-C if REFERENCE ELECTRODE laquoflaquolaquoCMraquo4r) pound
GLASSY CARSON SPHERE OMMETER -200raquogtCfm
04 03 02 01 00 -Ol -02 - 0 3 - 0 -05 -06 ELECTROOC POTENTIAL (rtAflAflCO (bullraquo()
F J2 Linear-sweep anodic stripping votUmmetry and coglometry of hianiirh efecfrodepooted onto a packed-bed electrode of gUscy carbon spheres Solid lines experimental current-potential and charge-potential curvet in ihe region of (he rmmuh stripping peak dashed lines estimated background charging curves
34
cajxabilify of the packed-bed electrode ot ciasv carbon tfetctci tot monitoring eieciroactrve species n molten sail has hem shown ugt be sattgttactor Consequently p bull aw now under wa raquo design jpd fabrKation ot cells and appaiaius lor sestmc the electrode system in mxten fluoride media induduw MSBR fuel salt- In Msmufh-coatauung fluoride metis whether bismuth iraquo present as Bt or LijBtor both it should be possible 10 identifgt and determine ihe quantities of each species The packed-bed electrode offer hope ut removin as well as monitoring dissolved bismuth m the fuel sail which may be present as a result of the reductive extracshytion process for removal ot fission products
iS FUEL SALT-COOLANT SALT INTERACTION STUDIES
A D Keimers D t Ilealherly
In the alternate coolant evaluation1 several areas of potential concern were defined with regard to the applishycability o( the conceptual design coolant salt | a B F 4 -NaF (gt2-K mole ^ l | for MSBRs These centered primarshyily arogtmd events associated with off-design transient conditions particularly primary heal exchanger leaks which would allow imermixing of fuel salt and coolant salt If coolant salt leaked into the fuel salt the quanshytity and rate of evolution of BF j gas from reaction lt 11
N B F 4 l d raquo o l j U M - B F l g gt bull N a F i d gt u e ^ lt I
would determine the transient pressure surges to be enshycountered in the heat exchancer and reactor Also preshyvious work 1 4 indicated a substantial redistribution of the ions LT Na Be F and BFlaquo~ between the resultshying immiscible two-phase system formed on mixing Lj BeFlaquo and NaBF 4 The solubilities of UF 4 andThF 4
have not been measured in such systems thus the disshytribution of uranium and thorium between such phases and the resulting concentrations are unknown In addishytion if oxide species were present in the coolant salt either deliberately added to aid in tritium trapping or inadvertently present due to steam leaks in the steam-raising system the precipitation of UO2 following mixshying of an oxide-containing coolant sail with fuel salt has not been investigated Therefore a series of experiments were carried out to investigate these areas
I J A D Kelmirs tl al Committer Report hvaluaiion of Alternate Secondary land Tertiary) Coolants for the Molten-Salt Breeder Reactor (in preparation)
14 V K Bamberger C h Baelaquo Jr J P Young and C S Shew MSR Program Semiannu Prop Rep reh 20 I96H ORNL-4254 pp 171 73
The experimental apparatus consisted ot a a u i u vessel heated by a quuri furnace so thai the raquoraquoraquottTvr of the resukmc phases ouid be observed at temp mure and measured with a cathetomrter The quari vessel extended up out of ihe furnace and was closed with an O-itne titling and end plate A nickci stilting shaft driven bgt a constant -speed dc r-fcgtllaquogtlaquo peneiiated the end plate and during live tests was dnven at a speed adequate 10 stir the two phases without appreciable vtsibW dispersion Access for sample fillet slicks was provided through the end plate as was done also for ihe argon inlet and exit lines A very low argon flow main-tamed an inert atmosphere over ihe melt during ihe experiment
Predetermined weights of fuel salt (nominal composishytion LiF-BeF ThF-lF 4 (Mfc-117-03 mole^raquo | and coolant salt |nominal composition NaBF4-NaF (2- mole ltl| were placed in the quart vessel and rapidly healed lo 550 C Bubbles of gas could be observed due to BF) generation via reaction I I I as soon as the coiilani sail melted during the heat up period When the temperature reached 550 ( counted as time zero stirshyring was initiated The volume ol the phases was periodshyically determined and filter-stick samples were taken at 30- or dO-rrun inieials
The reaction between the fuel salt and coolant sail proceeded slowly approximately 30 to raquo0 min was required to complete the visible evolution of BF 3 gas at 550degC When the initial coolant salt content was 20 wt or less of the total material no omlant salt phase remained after approximately I hr All the NaF disshysolved in the fuel salt phase and all the BF gas left the reaction vessel With larger initial weights of coolant salt up to 50 wt gt a small residual volume of coolant salt phase could be observed after I to 3 hr Severe corrosion of the quartz reaction vessel occurred at the interface between the coolant salt phase and the argon cover gas in the experiments with the larger initial weights of coolant salt presumably due to attack of the quartz by BFj via a reaction such as
2BF(g) + VjSiOjfc)- SiF4fggt + fcOjfd) (2)
In experimenis 6 and 7 holes were corroded completely through the vessel wall and the surface of the stirred molten coolant salt phase was exposed to air for I to 2 hr at 550degC
In most of the experiments samples of the fuel-salt phase were withdrawn at intervals of 1 2 3 and 4 hr Samples were also taken after the conclusion of the experiment after the melt had cooled to room temperashyture the quartz vessel was broken away from the solid salt All these samples gave essentially identical analyti-
Tabic 32 Compmiliun of fuel-Mil pliiH- ami cnulani-aalt phatv aflci contact al 550 C
h vpcrimenl No
Initiil imvlmc iwt raquo
Hu-I salt Coolant i lr
100 9( Ho 7l) 61) 51)
o II) o 3raquo 41) 51)
111
tgtHK 6 3 3 604 544 50H 44 0
I uclvill phase (mole gt
Nal IK-1 M i l I T
2 3 93
123 1911 63 366
17J 167 165 155 13 H9
NominaUomnoMUon l i l - -Bc l - -Th | - lt - l l (72-I6-I I7-03 mraquolc bull)
Nominal conipotttion Naltl- -Nul (92-K mole bull I
No coolant-suit phase remained
Not analyzed
115 105 106 |lgt9 96
ID4
I I I
I bull i2 IVH 94
Nal-
191 366 43 9
CoiiliiHvih phase IIIIOK- I
IWI l h l bdquo I T N i S i l
4 4 3H 3 9
ii IH n o l i (150 0 017 1)74 OlOH
lt 31 19
M 0 Nalll
lt5l IK 6 J 33
n 47
16 9
ft
36
cat values therefore tne fuel-salt phase analyse (Table 52) represent an average of 5 to 5 values Further supshyport lor the coateatun that react urns nrroHuK the fuel-salt phase were complete m feO mm c less t shewn In the plots of volume rs time in Fig3J The cootani-sai phase volume decreased raptdry tor about 30 mm due to reaction (1) thereafter the volume chance was slower presumably due to reaction i2h
It was irnpossibie to obtain coobnt-salt phase samples with the flier sticks both because the phase volume was small and the salt tended to dram out of the titer sticks Therefore aM coolant-salt phise analyses (Table 33) were from samples obtained after completion of the experiment and represent only smgje values
The analyses (Tabic 3 Jraquo show substantial redistribushytion of the ions Li Na and Be between the two phases Thorium and uranium exhibited low soiubiity in the coolant-sail phase Neither NaBF4 nor the oxyshygenated tluoroborate compound (represented as B 0 3
in the table) was soluble in the fuel-salt phase Fuel salt stirred in contact with a coolant-salt phase containing up to about 50 mole lt B0 3 showed no precipitation of LO Tht coolant phase compositions were ex-
onNL-DWG 75-raquo3748
rlX Claquo
1 0 -
X T
Cootant Solf Phase -
20 40 60 80 TIME (mi)
100 120
Fit bullbull Votame of coobnt-s-Jt phase and fad-nil phase vs fane in mixing experiment No 6 Initial mixture was 60 wi i fuel salt and 40 wt 1 coolant tall After heatiny lo 550deg C Mining was begun and tht depth of the two phase was periodishycally measured
F-laquo O
I n t u t i laquoaraquo4c bull
factual (bull4jac vilr Ml lt) ViM
l raquo bullbullbull 4gt gt- 5 bullbull bullraquo 4i M bullraquo bull bull bull
bullraquo 5 gtraquo MI 14
raquo - Na Nan bull Li bull ZBc bull 4Th bull 41 bull 4S
pressed (Table 33) m terms of the ternary system MF-B 0-NaBF 4 The compositions are dose to the glass-forming regions of the terra y phase diagram1 for the system NaF-BiC-NaBF where drscete comshypounds have not been established
The following pertinent observations can be made
1 The rate of evolution of BF gas on mixing was low- presumably the rate-limiting step is the transfer of NaF across the vflt-salt interface Thus in a reactor system with turbulent flow the release would be more rapid however these results are encouraging relative to MSBRs in that very rapid gas release reshysulting in significant pressure surges was not experishyenced
2 No tendency was observed for the fuel salt constitshyuents thorium or uranium to redistribute or to form more concentrated solutions or to precipitate folshylowing mixing of coolant salt into fuel salt These experiments do not yield information relative to mixing fuel salt into coolant salt since it was impossible to contain predominantly coolant-salt phase mixtures in quartz at 550C Thus the quesshytion of uranium (andor thorium) precipitation as lF4-NaF complexes as observed in an engineershying loop remains unresolved
3 Apparently an oxide species forms in the coolant-salt phase which is more stable than UOj since no LO-precipitation was observed Thus large amounts of oxygenated compounds could be added to the flu oroborate coolant salt for the purpose of sequesshytering tritium since leakage of such a coolant salt into the fuel salt would not lead to uranium or thorium precipitation
15 I Maya Sect 41 this report 16 H F McDuffie et al Assessment of Molten Salts ar
Intermediate Coolants for IWBRs ORNL-TM-2696 (Sept 3 1969) p 20
37
3 4 LATTICE AND FORMATION ENTHALHESOF FIR$T4tOlaquo TKANSmON^ETAL FLUORIDES
The pnmar bull purpose of (his inveMijpinw is to plaquoraquoraquowde a theoretical bans tor cnttcaiK evaluating the chermir-dynamic data thai raquoifl be blamed in an experimental program recently giiittled with Dmstuti ot Physical Research I undine In thf experureirraquo free enerpes of tormaiion will be deduced from emt measurements ot solid-etectriJyie caharuc ceHs The iirsi-roraquo transition rrcials include common sKucturai metab (Fe i Cgtraquo and other meuls iTi V) which may be used in fcaon or fusion reactors When these meuls are corroded or otherwise oxidized u fluoride media used m these resc-tors meial fluorides are formed reliable thermoshydynamic information for these compounds rs valuable in predicting their chemical behavior in the eactor system
For a metallic fluoride MFbdquo I where n is the valence of the metallic iongt the relationship between lattice enthalpy V and enthalpy ot formation is given by the equation
_y=-X Mgtbdquo nXly- ( I t
The lattice enthalpy is the best of the reaction
Mlggt + nV it) = MFbdquo(c) Craquo
at gtvl5 K The lattice enthalpy is very similar to the lattice energy the latter being someihat more diffishycult to obtain from experimental information 3Jr is the standard heat of formation of MFbdquo(c) A- is the standard enthalpy ltraquof formation at gtHl5 K of the gaseous cation and electrons ((gt formed from the crystalline metal
Hc)Mltg)+ gtlt( g) lt3gt
A-bull- is the standard enthalpy at ZW^K of a mole of gaseous fluoride ions formed from the ideal gases electrons and diatomic fluorine
V2F(sgt + ltr(g) - F (gf lt4gt
The enthalpies of formation for reactions lt3gt and (4gt are deduced mostly from atomic or molecular data Abdquo is obtained by summing the first ionization potentials of M and its enthalpy of sublimation and covcrling these quantities where necessary to 2ltraquolaquoI5 K values of bdquobull are given in Tables 34 and 35 The enthalpy of reaction (41 at gtXI5degKis ol24
Hmrraquotc bull Leal rrv-fcr
lt j l yi 5 4ilaquo 6 2 = si laquo2vraquo bull ltlaquo5i-Tiraquo bull 2 i v 5Slaquogt bullMgtC gt i2Wr 2raquoraquo i raquo f Crl I1 - 5 o5 3 6 - 5 Mnl 2ltgt5 4 - lf raquo 5 1 - I l-lt tif - 5 fc5s raquo - 5 C l - t5 - I f 2 laquo I V I 52 - bull raquo3 5 5 - bullltbull
t u t I I -bullbull 323 41 - - N nraquo I N Mraquo5 25
llaquolaquojgtltn rgt cntui-gt rmdashm lt I raquo-raquo- SRIgtS-IraquoS 34 bullgt cnhjlprs i ^uNinurn-n irin ret igt (atenve raquorjc prpjutraquogto encris sorretttrto irraquom elt 2 N BS Iivhnuai N-te 2gtMgt i llaquoI i ^iinucJ in this intetripibii ^NBS Icchnicjl V-ie bull-raquo 11t11 r V Rrufchiu tr j | iTim ThrmoJvn 6 bullbull( tgtraquo4( iXrrmrd tflaquom vgtlij ltal inkveil emf JJJ snmi in W H Sfcltr|[4i jnd J W Pjiicrv-n -laquoWtmmtm Mfidt 31 4 11 raquo-laquoraquo
f-IV-iF Thermhemif tehlt 2J e j NSRDS NBS 11111 I- Rudiicl jl J Oum rnt AifJ 1213 laquo11^1 NRS TcYhnhil tir raquobull lt fftSraquo
kcal per gram-ion it is based on Popps value 1 7 (34(H) eV) for the clectr gtn affinity of fluorine the dissociation energy lt 15 eV) measured by Chupka and Berkowit and the enthalpy difference of F (ideal gas) raquoraquo Hbdquo listed by lluiigren et al 1
The lattice enthalpies of the divalent fluorides arc listed in Table 34 and are plotted against atomic numshyber in Fig 34 The curious double hump has been intershypreted 2 0 in terms of ngand-field theory By this theory differences between actual values of A and those lying on a smooth curve drawn to fit the data of C a F Mnlj and ZnF are primarily due to ligand-field stabishylization energy (LFSfcl For (his series of compounds
bullThis rclaquoearcli in support of the MSRR Program wilt funded hy iho l-RIA Division of Physiiiil Research
17 II P Popp Xatitrforuh 22a 254 117) 18 W A ( hupka and J Berkowil Oiem Pint 54542h
ii nn 19 R Hullcren el al Selected ialun of the T)icrmltgt
dynamic Properties of the Elements p 177 American Society of Meials Metals Park Ohio 1973
2lraquo P (leor-e and tgt S McCliire p 381 in Progress in Inorganic Chrmisln vol I I- A Cotton ed Inieruience New York I W
M
750
_ TOO mdash
o E
x
690
6 2 0 -
I I I I I I I
I I I i I I I I I Cefj Stfj Traquoj V Crfj M Wgt laquo j MF 2 C 2 amp2 ddeg (T d 1 d J d 4 5 draquo d draquo draquo d
Fltg- 34 Lattice wlnaifiM of 3rf diva l l w i l u Solid circle (bull) are experimental aML catenated from Eq 11)error bars art uncertainties in ampH Open circle (-) are AftL mam Iwand-fldd stabilization energy Tnangks (A) arc aW^ minus both LFSE and Jahn-Tener energy Solid squares ltbull) were estishymated by adding LFSE plus 3 kcalmote as an empirical correcshytion to the smooth cone
the ligands are fluoride ions octahedrally coordinated (except for CaF 2 ) to the cation the ocuhedral field of fluoride ions acts to stabilize the splitting of tf-electron energy levels of the metal ions In a spherishycally symmetrical field the (-electron levels would be degenerate that is be at the same energy In Fig 34 the smooth curve drawn through for example N iF 2
represents the ampHt N i F 2 would have if the field of fluoride ions around the nickel cation were spherically symmetrical Octahedrally coordinated cations with unfilled half-filled or fully filled 2d orbitals will not have a ligand-field stabilization energy hence a smooth curve is drawn through CaF(tdeg) MnF(lt 5) and ZnF2(ltdeg)
Values of the LFSE can be deduced from optical spectra For FeF N i F 2 and CoFj subtraction of optically derived LFSE (Table 36) from bHL yields values (open circles in Fig 34) which are above the smooth curve by 2 to 3 kcalmole Similar LFSE subshytractions for CrF and CuF yield values (denoted by
laquoraquoraquo-raquo
Fhoodc iHf bullraquo- plusmnHL
ikai nMle) ileal mmfT l U a l motel
ScF 3941 2 1112 13224 r 2
w 33 1 3-$ 1222 1374 t 35 V F 2 9 S S I29raquo 1499 O F 277 US 14 I44S l 2 3 ^ I3gt l 143 t F e f bullSHi 13V4 1431 3 CoF mjf 1455-J 1457
N O W 1515-5 bull I 4 9 7 C - F ( 1 2 0 I S M 11520 lt - F 2 7 I3S9 143
bullban pomoMs from C E Moore SSKDS-NBS 34 (1970) earailgiri ot inlilmdashiliun from ref 19 catrnce state preparation energy correctnas from rcf 20-T N KeiaHani cf a l Cktm Tkrrmodrn t90 (1974s eO Kabascfccwsfci et at pp 3343S4 in JMrMftWpaf Iktmso-chematry 4th cd Pergamon Oxford England 197 Derived from toad garantc-cdl emf data gjien in W H Skdion and J W Patterson Less-Common Mruls 31 47 (1973) MBS Tetkmfl Note 270-4 (1969) fjASAF TkermochemicM Ttblts 2d ed NSRDS-NBS 37 (1971) Estanaied m this mvcstiplion hNBS TethmeitSote 270-3 (I96S)
open circles) above the smooth curve by 5 and 7 kcalmole respectively Both C I F J and CuF 2 (and to a lesser extent F e F 2 ) are known from crystal structure data to exhibit major tetragonal depai mdashres from octashyhedral coordination geometry This is attributed to the Jahn-Teller effect 2 which confers an additional stabilishyzation energy (Jahn-Teller energy is abbreviated herein as JTE) For CuF 2 and F e F 2 the JTE can be derived optically (Table 36) When LFSE and JTE are addi-tively applied to CuF 2 and C r F 2 the lattice enthalpy is overcorrected as is shown by the triangles in Fig 34
The methods outlined above can be applied to predict A t for V F 2 and T i F 2 Neither compound would be expected to have a significant JTE The formula used is
(5) Atfpound (kcalmole) = AHL bull LFSE + 3
where A V is the value for the compound lying on the smooth curve in Fig 34 The 3 kcalmole on the right-hand side of Eq (5) is an empirical correction reflecting
21 F A Cotton and C rmced Inortnic Chemistry 1972
Wilkinson pp 5deg0-93 in Ad 3rd rd Inter science New York
J9
OFSEk UTEXwl
IkvWt i lrgtH
H raquo T i 4 r |-ltU| OK laquo bullk-jl BRiic bull id lt
III ik^ai n-4ri
J S - l iraquoraquo I l raquo laquo n f i bulllt bull-
J- T i l bull I l Twr bull Mi t | 5 _ W 3raquo4
Jy gt f rlaquolaquoraquo laquo bull gt lt l | 4J6laquoI 5 laquo raquo l
J O K 1 laquobullbull l l raquo lt raquo I l f M a t l~4im bull bull bull I i
J- YtY 6raquogt - a I4i raquo -9
lt t raquo l 114ml lvi
J t raquo l Z l K I lb 5 Nil- lfc21 T I
J N i l 4 i m 54 lt u l I4UI0 4X4
J lt u K 4iKi 15 bull ~5t l raquo
JVjluc tivcn in D Orlkru Strut I RonJmg Berlin- 9 I 2gt 11raquo~Iraquo unlf otherwise m-JiutrJ l I SI minuinl very rlaquouchlgt i bullbull of Til- BiscJ ltgtn K N i F i l
Ksiirruted by jviumini lWgtq n ihj of Til-
Bjlaquod n iNH i gtVI Klinutrd hy Jraquorlaquonltcn mclhod |igtIX) jr r =1 -raquoltraquo cm --bullraquobullraquo Rouen t-Mirruic from JTI oi CuK Hiraquo-d n K( raquol ( ( Allen and K O Warren Struct laquorraquonWf SWw 9 Igtraquo7 nlaquogt| i
40
1550r
1500-
I I I I ORNL - DWG 75 - raquo3750 r I r
i i i I I l l I I ScF TFj VFj Crf MrF5 FeFj CoFj IWF CvF(ZnF)GaF ddeg d d d 1 (J4 d s dlaquo d 7 ltfraquo draquo d laquo
Flaquo 3 3 Lattice enthalpies of id trivalrnt Amides Solid bulltrclraquo laquoraquoi ace experimental plusmnH calculated from Eq (1gt error ban are published uncertainties in plusmnh Open circles ( ) are Af minus ligand-fteld stabilization energy Solid squares (bullgt are estimated by adding LFSF to the smooth curve
the difference between theoretical and thermochemical lattice enthalpies for NiF2 and CoF 2 The standard enthalpy of formation (Aygt for TiF2 and VF 2 is then obtained from Eq (1) and is listed in Table 34
Analogous considerations were applied to study AW for trivalent fluorides The data and results are preshysented in Table 35 and in Fig 35 The double-hump pattern of the data is evident in Fig 35 Subtraction of LFSE (given in Table 26) yields very satisfactory agreeshyment between theoretical and experimental lattice enthalpies of VF 3 and CrFj the agreement for TiF 3
(and for CoF 3 ) is less satisfactory As may be seen by the open circle below the curve in Fig 35 subtraction of LFSE from AHf overcorrects MnF 3 This is someshywhat surprising since MnF 3 with its 3d electronic configuration for Mn also has a azable JTE (Tabe 26) f the JTE were also subtracted the discrepancy from the smooth curve would be much greater In short the thermochemical data for MnF 3 are questionable
In estimating $HL and A for NiF 3 and CuF 3
(Table 35) only the LFSE was added to the spherically symmetrical values (ie smooth curve values) of ampHL In other words Eq (5) was applied without the empirishycal correction of 3 kcalmole
With regard to the A of the structural-metal fluoshyrides the theory as applied above suggests that there is little need to determine AVf for NiF 2 Moreover from the value of Afy of TiF 2 obtained in this study it is understandable why TiF 2 has never been prepared as a pure solid it can be easily shown that TiF 2 would readily disproportionate to TiF 3 and Ti However a more accurate experimental determination of A7 for TiFj would be desirable for both practical as well as theoretical reasons The same may be said for V F 2 VF 3 CrF2 CrF 3 FeF 2 and FeF 3
4 Gootint-Sak Chemistry A D Ketmers
41 CHEMISTRY OF SODIUM FLUOROBORATE
L Maya W R Cahill
The composition of the condensable fraction of the vapor piiase in equilibrium with molten fluoroborate can be defined by the system HuBF 4-HB0 2-H 20 as described in the previous report1 The work done durshying this report period was aimed at spectroscopic identishyfication of the molecular species present The B NMR as well as IR and Raman spectra of BF-2HjO FSFi(OHh- and of other intennediate compositions was obtained Dihydroxyfluoroboric acid (DHFBA) participates in exchange processes which could be desshycribed by the following equilibria
2HBF2(OH)2 = BF -H 2 0 + HBO
BFj-H 0+HBO = BF-2H 20 + HB0 2
The presence of HjBOj and HB02 was detected by 1R and Raman spectra and the pronounced broadening of the F and B NMR signals is an indication of exshychange processes The Raman spectrum of DHFBA indicates that this compound is a tetrahedral molecule Exchange processes were not detected for BF 3-2H 0 This compound appears to be stable at room tempera-twe The structural information derived from the Raman spectrum which identified BF 2H 2 0 as a
tetrahedral molecule agrees with the x-ray structural determination2 of this compound
Additional samples of condensate collected during the operation of the Coolant Salt Test Fanlity (CSTF) were analyzed (Table 41) Silicon is present because of attack on the glass trap used to collect the condensate Variations in the chemical composition of the samples can be interpreted as an indication that the condensed material is not a single molecular compound but rather a mixture formed by combination of the simpler gasshyeous species present gtn the system that is H 2 0 HF and BF The relatively high tritium content of these fractions should be noted Tritium is present in the system since some oi the Hastelloy N in the Icop was originally used in the MSRE The condensates show a tritium concentration factor of about I0 5 relative to the salt suggesting that fluoroborate coolant salt [NaBF4-NaF (92-8 mole )] may be sn effective means of concentrating and conveying tritium out of ikt system
Attempts were made to generate a condensable fracshytion in laboratory-scale experiments by heating oolant salt containing up to 200 ppm H as NaBFOH to 400degC in a closed system equipped with a coid finger The OH~ concentration in the salt decreased to 50 ppm and the composition of the condensate in a typical run was 532S H0BF 41483 (H0) 2SiF t anr 32^ free water found by difference The boron concentration in the condensed material did not reach as high a level as in
ORAL summer participant I L Maya MSR Program Semiannu Progr Rep Feb 28
VZ5 ORNL-5047p47 2 W B Barn and G B Carpenter Acta Ova 17 742
119641
TaMr 4 1 Analyses of CSTF trap coadeasttes
Sample Operation period Amount Chem
HOBF
ical compoMt ion Tritium content
imCifi Operation period Amount Chem
HOBF HBO SF
Tritium content imCifi
1 2 3 4
1972 11475 12475 31475 41575 41575 56lt75
Not avail 100 me
25 f 800 me
604 923 841 830
157 0
124 121
Not del 21 40 01
08 lo 30 r
57 34 06
Approximate amount Some of the material remained in the trap ^Difference(torn I0fr nH0 Given at a ranee Apparently more than OM simple was analysed for tritium content Data from A S Meyer and J M Dale Anal Chem [Mr An mi Pto0 Rep Jan 1974 ORNL-4930 p 28 The loop was not in operation between 12475 and 31475
41
42
the CSTF samples and there was considerable cor-bullosion Nevertheless these experiments showed a posshysible mechanism for the conversion of dissolved NaBFOH into a volatile fraction
An apparatus was assembled to measure he vapor d^rcity of BF i -2H G and related compounds at eleshyvated temperatures to determine the degree of dissociashytion of these materials This work tested the hypothesis that the condensable materials collected in the operashytion of the CSTF are completely dissociated at opershyating temperatures (+00~600C) and only combine to form more complex molecules in the colder parts of the system The procedure consists in measuring the presshysure developed in a closed system conuining a known amount of BF -2H 2 0 or DHFBA in order to establish the degree of dissociation according to the equilibrium described below
BF-2H 2 0 = BF+2HjO
At this time volumes in the apparatus have been detershymined and pressure determinations have been made using argon as a test gas Initial runs with BF 3 2H 2 0 indicate that this compound may be completely disshysociated at 400degC
Work on determining the oxide species present in molten fluoroborate is being continued and the survey1
of the system NaF NaBF4 BOj at 400 to 600degC has been extended to include IR and x-rav diffraction analyses in addition to physical and chemical observa-tiorii of the behavior of ^elected compositions The observations indicate that there are three main areas in the system
1 A region of compositions in which BFj is evolved This occurs with compositions having a deficiency in terms of equimolar ratios of NaF relative to the B 2Oj present
2 A region of compositions in which stable glasses are formed on cooling This corresponds to mixtures containing more than 33 mole B 2 Oj
3 A region in which crystalline phases and glasses coshyexist The tendency to form glasses on cooling decreases with decreasing B 2 0 j content
Usually coolant salt (NaBF4-NaF (92-8 mole )| contains relatively small amounts of oxide up to 1000 ppm and its composition lies within area 3 thus work has been directed toward characterizing the oxide species in this area At least two species were present one formed at the boundary of the glass area (high oxide content) and the other was NajBjFraquoOj which formed in compositions having NaFNaBF 4 B 2 0 mole ratios of 221 and 241 and was possibly present in
compositiors containing as little as 3 mole 7c BjOj Experiments at the 15 to 40 mole B Oj level approaching the coolant composition have been imshypeded by the relatively low sensitivity of IR and x-ray powder diffraction The difficulty with IR using the KBr pellet method arises from the fact that ~t thlaquoe oxide levels the only band not covered by BF 4~ absorptions is the one at 810 cm 1 This band has a relatively low absorptivity and it is common to NaBFOH NaiBzF0 N a B F t O and possibly other BOF compounds although the intensity and line shape are different for each compound A more certain IR identification can be made only when at least two topical bands can be identified (presently observable only at higher concentrations) as was the case in the identification of N a J B 3 F t O J at an oxide level correshysponding to 14 mole BJOJ Difficulties with x-ray diffraction arise from the low sensitivity of this techshynique coupled with the fact that the species have a tenshydency to form glasses Raman work on melts is being planned as the next step in this study
42 CORROSION OF STRUCTURAL ALLOYS BY FLUOROBORATES
S Cantor D E Heatherly B F Hitch
Alloys containing chromium in contact with molten NaBFlaquo-NaF would be expected to form a boride beshycause the reaction
(I + jr)Cr(c) + NaBF 4(d) + 2NaF(d)
= NaCrF(c)Cr xB(c) (I)
has a negative standad free-energy change (AG 0) At a temperature of 800degK ACj 0 o = - 1 0 kcal This value is based on an estimated standard free energy of formashytion (SGj) of NaCrF of -600 kcalmole In reaction (I) the exact value of x is unknown however AG of the more stable chromium borides (Cr2 B Cr5 Bj) is estishymated to be - 2 2 kcal per gram-atom of boron1 In nickel-base alloys reaction (I) may proceed more readily because of the probable exothermic nature of the reaction
CrTBfcgt +yNKalloy) = Cr(alloy) bull NiyBfc) (2)
3 O H KrikoriMl EstiirMion of HtJl Capacities and other Thermodynamic Properties of Refracsorv Borides UCRL-51043(1971)
4 O S GordkiN A S Dnbrovm O D Kokimkon and N ACherkovfun toys Chem 44431 (1972)
43
Assuming that AG of NiyB equals its enthalpy of formation AG for reaction (2) is about - 3 kcal per gram-atom of boron
An experiment to determine the extent of boride formation in the nickel-base alloys Hastelloy N (7 Cr) and Inconel 600 (15 Cr) has been in progress for sevshyeral months In this experiment mrtal specimens are equilibrated with NaBF4-NaF (92-8 mole ) at 640degC under an argon atmosphere and are periodically reshymoved washed free of salt using water and analyzed by spark-source mass spectrometry (SSMS) and less routinely by ion mkroprobe mass analysis (IMMA)-1
Analysts for boron on specimen surfaces by SSMS sugshygests some boride formation Hastelloy N specimens that had equilibrated for up to 129 days were found to contain 30 to 1000 ppm B Inconel 600 specimens conshytained 80 to 2000 ppm B Control specimens that had not been in contact with the molten salt showed 5 to 20 ppm when analyzed by SSMS Boron in Inconel 600 increased with equilibration time but with Hastelloy N the data were much more scattered and showed virshytually no time dependence
Several specimens analyzed by SSMS were also investishygated by IMMA Boron was present within the first few hundred monolayers of metal in inclusions also conshytaining sodium and fluorine in specimens of 2 Ti-modified Hastelloy N that had equilibrated for 72 days These contained 150 ppm B as determined by SSMS
5 Spark sowce mas specttomeuv and ion microprote mau analyss performed by die Analytical Chamstiy Dmson
The only plausible explanation seems to be that some NaBFlaquo remain on (or in) the metal surface despite the vashing (5 -10 nan in boiling water) intended to remove adhering traces of salt Some of the scatter in the boron analyses by SSMS is probably due to salt contamination of the metal surface Inconel 600 specishymens scanned by IMMA sholaquoed a similar pattern of surface inclusions contami^f B Na and F Unfortushynately IMMA does not provide quantitative analyses for these elements As yet the extent of boride formation cannot be quantified in either Hastelloy N or in Inconel 600 by a combination of SSMS and IMMA Probably however reactions (1) and (2) occur to a small extent boride is deposited at levels not greater than 500 ppm bullin Hastelloy N and not exceeding 1000 ppm on Incond 600 after four months of contact with molten NaBF44aF
IMMA was also used to obtain depth profiles of alloy constituents through about 5000 layers In control specimens elemental concentrations were uniform with depth far equilibrated Hastelloy N molybdenum was uniformly distributed throughout the depth explored but chrofiuuip and titanium concentrations increased linearly from the surface inward the iron concentration appeared to decrease slowly with depth Equilibrated Inconel 600 showed virtually no chromium in the fust 500 layers but chromium increased linearly in the next 4500 layers iron and nickel were uniform through the depth studied Thus IMMA indicates that chromium is selectively oxidized by NaBF -NaF (92-8 mole gt or by oxidants contained in this molten mixture
5 Development and Evaluation of Analytical Methods
A S Never
51 IN-LINE ANALYSIS OF MOLTEN MSBR FUEL
R F Apple D L Manning
B R Clark A S Mever
Corrosion test loops described previously have conshytinued operation with circulating reference fuel carrier salt LiF-BeF2ThF4 (72-16-12 mole ^ ) No additional loops hart been placed in operation during this reportshying period although several ire expected to begin opera-lion within the next few months
Measurements of the U-3 ratio in the forced conshyvection loop (FCL-2b) indicate a steady-state value of about 100 (Fig 51) This is somewhat lower2 than the
1 H E McCoy el al MSR Program Senumnu Progr Rep ug 31 1974 ORNL-50 I p 76
2 A S Meyn ec al VSt Program Semtcnnu Pro Rep Feb 28 1975 ORNL-5047 p 52
i MNL- om 75-1205
lt 1 1 1
3 V f mdash
amp amp amp
s 8 - i
bull bull
c I -J
m c
1 - i
-
2 bull bull
1
bull bull bull bull bull bull
raquo
bull bull bull
J _
bull bull
bull mdash
90 100 ELAMCO Tim
ISO 200 ltlaquobullraquoraquo)
apparent steady-state value obtained with the fluorid mixture LiF-BeF-ThF4 (68-20-12 mole 5gt indicating a less oxidizing melt The melt which started al a ratio of around 1000 reached this level via a redox process which presumably involves iactraquolaquoi ith the chromium in the walls of the vessel or in the specimens No atshytempts have yet been made to reoxidize the U3 in the melt by suitable additions of NiF or some other oxishydant It is interesting that the decrease to a steady-state value occurred after about 75 days ith a rapid deshycrease in the first 30 days Previous data from the expershyimental fuel showed2 a rather stable value near 10 for aoout 60 days until beryllium additions were made to force reduction of the U4
Some of oscillations in the data probably result from air contamination with subsequent oxidation when the loop was down This was most prominent with the experimental melt (68-20-12 mole S ) when the U43 ratio was substantially greater than the steady-state value reached at a later date
Ratios of U7U measured in the two thermal conshyvection loops NCL 21A and NCL 23 are summarized in Figs 5_2 and S3 respectively No unusual trend is apparent in the oxidation-state history of the fuel melt in NCL 21 A This loop was operated for about 240 days with Hasteiloy N corrosion specimens The curve shows a rather dramatic rise in the ratio whenever new specishymens are added This effect is attributed to additions of moisture and air which partially oxidize If3 A recover to lower ratios follows each increase in repetitive fashshyion
rj 1 t
OMl-Mt 79-OOSr 1 1 i
5 w i 1 V z
s Jr X
I bull 1
i 1 f
4 ^v bullw raquo bull
1
mdash bull
i i
bull bull
1 A- 1 100 190 ELAPSED TMfC
200 I )
290 300
FfcS1 Lmdash l gtFCL-2fc Fig 5J
NCL-m vmdashw
44
45
ORNL- DWG 75-12055 i i
1 i 1
2 bull 4 mdash 8s laquobull bullo
=3 i 3 bull copy
y i
bull bull bull bull I 1
i X bull bull bull
bull I I raquo IA raquo s s
bull bull bull bull bull bull
bull bull bull bulllt
laquo bull
I i 1 1
50 100 150 200 ELAPSED TIME (dors)
F4- 5-3- L LJ- ratios M rfcemal cowcctioa loop NCL-23
250
The U in the mdl in the Inconel 6CI loop NCL 23 wso aptdly retiuoed untS a V^iU ritio of around 40 was reached Since then the ratio has continued to decline reaching a relatively stable value near 5 The high level of chromium in the Inconcl 601 (23 wt lt) provides a sufficiently active reductant to reduce the U 4 more extensively than has been observed in Hastel-loy N loops therefore the greater U 3 concentration is not surprising
S2 TRITIUM ADDITION EXPERIMENTS IN THE COOLANT-SALT TECHNOLOGY FACUITY
R F Apple B R Clark A S Meyer
One major concern in the development of an MSBR is the release of tritium to the surroundings A potential method for limiting tritium release rates to acceptable levels involves trapping and removal of the tritium in I lie secondary coolant system This method must be tested before a complete understanding is possible of the manner by which tritium will be retained in an MSBR The present series of tritium addition experishyments involving sodium fluoroboraie will provide data on his method
The Coolant-Salt Technology Facility (CSTF) is being ltperated for testing the NaBF4-NaF eutectic mixture
with regard to its suitability as a oossible secondary coolant system In cooperation with loop engineers and technicians the Analytical Chemistry Group has been engaged in experiments to determine the fate and behavior of elemental tritium added directly to the cirshyculating salt to simulate at least in part the predicted transport o tritium into the coolant system via diffushysion through the primary heat exchanger This section describes the methodology and results of the first two experiments
About 80 mCi of tritium (diluted about 11000 with protium) was introduced into the salt stream over a period of about 11 hr beginning on July 17 Tritium concentrations were measured in the salt and the cover gas during the addition and for several days thereafter Salt samples were collected directly from the pump-bowl access port with a copper thimble covered with a copper frit One-gram samples of the cooled salt were diluted volumetrically and aliquots were mixed with a scintillation emulsion for beta counting
Cover-gas sampling has proven to be somewhat diffishycult At present a sidesfream is being sampled the diffishyculty arises from the passage of this stream through a nickel sampling line that is not completely inert chemishycally to cover-gas components Thus the amount of eleshymental tritium finally measured may not be an accurate
46
measure of tritium level within the loop gas system-More definitive experiments will require the use ot inert precious metals in the sampling system to remove doubt of chemical alteration of the cover-gas stream composishytion by the sampling system
The off-gis collection train consists of
1 a series of three water scrubber pretraps which serve to trap BFj and any other water-soluble compounds
2 a hot (400degC) copper oxide-tilted tube 3 a condensation trap to collect water formed in or
passing through the copper oxide 4 a liquid-nitrogen cold trap to remove the last trices
of water 5 a wet test meter to measure the volume of the iner
gas component of the cover gas that is helium
Results of the first injection experiment are summarized for the offgas (Table 51) and salt (TaWe 52)samples
Several days after operation had begun some liquid collected in the short glass section between the stopshycock used to divert the gas stream and the first trap in the analysis train The liquid was washed from the glass counted and found to contain about 60 jiCi of tritium This discovery clearly complicates the interpretation of previously collected samples since a large portion of total cover-gas tritium never reached the analysis train Furthermore no conclusion is possible regarding the chemical state of the tritium in the liquid The data suggest urn the concentration of elemental tritium
TabkSI TritimroMcM
iaCSTF
Tritium in ltas Time tpCimO
HOvluWe Fiemcnlai
17 1046 23 34 1305 07 12 1700 14 170 1 9 i i 1 93 2243 14 830
18 0100 32 420 0805 73 61 1000 44 71
19 1037 790 62 21 0905 1800 13
1325 50 13 22 0925 55 58 23 1303 85 29 24 1000 300 22 25 1315 340 26 28 1245 10 27
TaMrS2 TtitmmcoatcM mslaquot sMf tn rflrtfiol w i l i i jjiiwon mCSTF
Date July
Simple No
Time Tritium inCi (l
1 45 IKW 12 46 I3MS raquo 47 1512 35 4 1718 51 49 1930 9 j 50 2145 73 51 2321 H 2
1 52 1102 32 53 1912 20
laquo 54 9130 15 SMV 0952 75
21 55 1132 16 bullraquo2 56 1400 16 23 57 1330 20
increased in both the cover-gas and salt samples when the liquid was washed out between sampling periods I July 23-25)
A second tritium addition was made August 5 During this experiment no changes were made in the sampling apparatus but that region of the sampling train (desshycribed above) where liquid had been accumulating v as washed with each sample collection and counted sepashyrately The tritium found there was added to the water-soluble tritium measured in the pretraps Data for this experiment are summarized in Tables 53 and 54
An exhaustive analysis of the analytical and sampling aspects of these data is not warranted at this time since several variables which affect the addition sampling and the tritium losses have not yet been established A general discussion on the oehavior of tritium in the CSTF is given elsewhere1 The preliminary data are sufshyficiently encouraging to merit a more extensive investishygation into the extent and mechanism of tritium intershyaction with sal and cover-gas components Plans are now under way to monitor the tritium diffusion through a portion of the loop wall and to measure the level of active protons in the salt during addition of tritium A more intricate bull over-gas sampling device (a probe designed for the sart monitoring vessel or salt sample port) is being considered and may be fabricated if no simpler solution to the gas sampling problems can be found
3 Reference Sect 112 thn report
47
TaUeS3 Jiitmtm content in cover-gas amahs after jtvoad tritium aMinoa
mCSTF
Tricium m ja D l l e rime laquopCimll
(AlKWM) HOvi luhk HcmenuJ
5 0730 96 o5 ltmraquo HO 2 2 1130 22oo 10 1330 5JWgt 20 1530 7500 27 1830 13000 34 1920 13000 39 2100 12000 40 2315 9300 39
6 laquoP3n 9300 2 I I mi ltraquo) 16 1500 6500 i4 2000 4700 10
7 0940 3300 68 1415 2400 49
O93o ltraquo00 34 9 1450 1600 52 to W40 1300 2 1 1230 900 2 J 12 1010 570 11 13 1010 23o 0 15 inoo 1X2 lO llaquo iraquo935 76 05 21 1010 73 o j
TaMr 54 Tribmn content m sak s a f k i after moan H i r i mdash aaditioa m CSTT
Dale Sample Trunin iAapnU No m lad-e l
4 5 1313 nraquo 5 59 (1954 90
60 1145 21 61 1350 36 62 IS4ft 52 A3 IX4X 7 | 64 1932 6ft 65 2125 71 66 2335 50
6 67 lift in 30 6ft 157 19 A9 2 lraquo 16
7 To IOI4 9 5 71 152 ft 1
T 1 lolft 36 9 73 0916 4 2 I I 74 124ft 39 12 75 1035 14 13 76 I04K ^ 1
15 77 IOIO 14 I I I 7raquo IOIO 07 21 SMV IOA l3fW o5
5 3 ELECTOOANALYT1CAL STUDIES OF IRON II) IN MOLTEN LiF-BeFj-TkFlaquo
(72-16-12 MOLE 9tgt
D L Manning G Mamantov
Electroanalytical studies in molten fluorides have particular importance tor possible use as in-line analytishycal methods for molten-salt reactor streams Irani II) is a corrosion product present in molten-sIi reactor fuels We have previously carried out electrochemical s tud ies of i r on ( l l ) in molten LiF-NaF-KF ( 4 6 5 - 1 1 - 5 - 4 2 0 mole L iF -BeF 2 -Z rF 4
(696-254-50 mole ) and NaBFlaquo-NaF (92-8 mole ) Since the fuel solvent for the MSBR is a thorium-containing salt LiF-BeF ThF 4 (72-16-12 mole )it is of interest to conduct vortasnmetnc and chronopotenti-ometric studies of irondl) in this fuel solvent To detershymine concentration andor diffusion coefficients by linear sweep voliammetry it is necessary to know whether the product of the electrochemical reaction is soluble or insoluble The measurements discussed bdow were dace with this purpose in mind
A volummogram showing the reduction of ironOU Fe2 -raquo Fe at a gold electrode is shown in Fig 54 The circles represent the theoretical shape based on current functions tabulated by Nicholson and Sham for reversible wave where both the oxidized and reduced forms of the electroacthre species are soluble Thus even though Fe2 is reduced to the metal at gold the electrode reaction very closely approximates the soluble-product case apparently through the forrmtion of iron-gold surface alloys Further evidence that the Fe3 - Fe electrode reaction at gold conforms to the soluble product case is illustrated by the chronopotenti-ograms in Fig 55 The ratio of the forward to reverse transition limes ir^r) compares favorably with the
4 D L Mannmc Votcaninernx- Sradaroif Iron m Molten Lif-Nar--Kr fVermwwj Chen 6 2 2 7 i | 9 6 3 l
5 D I Mannine and G Manunfti X j p d San Voium-metric jnd CrirraquonnjgtotentKgtroeirraquo Sludirt igtf Iron in Molten H w r e k W tleclmtntl Oirm 7102 H964raquo
6 I I W Jenknu D I Manmae and O MamantoT Flec-irnde fotentiaU of Several Redlaquo Conple in Mollcn Hno-rnfeO Nmntchrm Sgth 1171 S3 119701
7 f R Clayton it HeciiochemK-jJ Slwbe in Molten Hnoride and Fraorntmrawv doctoral dtunalnm Imvenm of Tenncvee December 197) p ft2
ft A S Meyer et j l MSft Program WniMwn rop Rep Aug M 9 T 4 ORNl-laquo72Xp 44
9 R S Nicholson and I Sham Theory of Stationary FKtrode foiarocraphy J Oitm 3 7 0 7 I | 9 O I
48
QWNL-PWG 75-11275
I I I I I I I 150 tOO 5 0 0 - 5 0 -WO -150
POTENTIAL mV
Fy- 54 Stationary electrode watamumapam for e refacshytion of r V af gt faM electrode bull Broken UF-ueF-TnF Po-lentil axis B ltf - poundbullraquo-- Solid line is experimental Circles are theoretical dupe lor soluble product Iron) III concentration 0027 f electrode area 025 cm s lemperature 650 C
theoretical value of 3 (ret 10) for the soluble case which again points to the formation of surface alloys
The reduction of Fe2 at a pyrolytic graphite elecshytrode is illustrated by the vultammogram in Fig 56 and the chronopotentiograms shown in Fig 57 For the reversible deposition of an insoluble substance where n = 2 the voltammetrk Ep - pound p I = 303 mV at 650degC (ref II ) is in good agreement with the experimental value The chrooopotentiometric ratio (zyrr) is approxshyimately unity which also h indicative that Fe2 is reduced to metallic iron without any apparent interacshytion with the pyrotytic graphite and that all the iron is stripped from the electrode upon current reversal Therefore iron appears to be reversibly reduced to a soluble form at gold and to an insoluble material at pyrolytic graphite Thus the effect of electrode subshystrate on an electrochemical reaction is illustrated by this example
Chronopotentiograms for the reduction of Fe2 at an iridium electrode at 518 and 60DdegC are shown in Fig 5 8 The ratio at S I8degC is approximately unity and is 3 at 600 a C which is evidence that Fe1 reduction at iridium approximates the insoluble-species case (as with pyrotytk graphite) at SI8degC and the soluble-product case (as with gold) at 600degC This change in reduction behavior with temperature was not as pronounced at gold or at pyrolytic graphite
10 W H RimjnMn Oirowopoecmwiweiiic Transition Times and The Interpretation^W Chem 321514 (l0gt
11 C MwuMm D L Manm and J M Dale Reversshyible Drpnsitrxi of Metal on SoM Electrode by Voflammetry wnb Linearly Vary in Potential tlrctntml Ckem 9 253 tl9raquo5gt
The chronopotentiometric transition time r for an ekctroactiw species is given by the Sand equation 2
Average diffusion coefficients oi Fe2 in this melt evalushyated from the chronopotemiometric measurements by means of the Sand equation are approximately 42 X 1 0 80 X 10 and 15 X I0 5 o n 2 sec at 5IX 600 and 7O0degC respectively
54 VOLTAMMETRIC STUDIES OF TELLURIUM IN MOLTEN UF BeFThF 4
(72-16-12 MOLE )
D L Manning A S Meyer G Mamantov
Tellurium occurs in nuclear reactors as a fission prodshyuct and results in shallow intergranular cracking in structural metals and alloys i It is of interest to charshyacterize this substance electrodiemicaliy and ascertain the feasibility of in situ measurements by eiectroana-lytical means We previously14 carried out preliminary polarization measurements at a small tellurmin poc1
electrode in molten LiF-BeFj-ZrF to estaampbh (he potentials at which tellurium is oxidized and reduced in the molten fluoride environment These preliminary observations indicated that the electrode reactions are complex
For tellurium screening studies J R Reiser of the Metals and Ceramics Division fabricated an experishymental cell equipped with viewing ports and electrode ports for studying the stability of lithium teUuride LijTe in molten LiF-BeF-ThF4 The Li2Te was added as pellets following which voUammograms were reshycorded at gold and iridium electrodes
As LsTe was added to the melt the voliammograms became com4ex and are not yet completely undershystood For clarity pertinent observations at the iridium and gold electrodes are tabulated separately
1 Upon adding one 35-mg pellet of Li 2Te a reducshytion wave observed at 09 V vs the It quasueferencc electrode (ORE) disappeared- fhis wave is not yet
12 Pan Drlahay p 179 IT in Srw hturumenuH Mrlkodt m Eltcmxhrmotry htterscience New York 1964
I J H F McCoy Maiernh tor Salt-Tontammt Veswlsand Pipmt The Dtvrktpmtni mtd Vlaquoftn of Mollrn-Sali Rnclon OftNMH|2ll-ebnary 1975raquop 207
14 A S Meyer el j | JW hnmm Stmmmmi Prop Rrp Aug SI 1974 ORNL-5011 p 42
49 ORL-0G 7S-M277
OWEVT TiME CURRENT TIME n l tslaquocdraquo) (mA) (stcdw)
5 J Cyclic ibroouyofcplimi mdash i for w wountioa of bulloa j l l ) at a f o M efcinuiat Foraufciy of troMllt X15ttecti ode jrcj
identined The pellets did not melt or dissolve immedishyately Relics ot the pellets could be seen on the surface tor several days The windows of the viewpcris became coated with a bluish-fray deposit after a few days making viewing of the melt impossible The bluish-pay deposit is believed to be tellurium metal Tim indicates that tellurium species added as L i Te are not stable in the melt
2 Voltammograms recorded in molten LiF-BeF -ThFlaquo after additions ot Li Te did not reveal any waves that could be attributed to soluble dectroactive tellushyrium species Chemical analysis indicated lt5 ppm Te in the melt
3 Abo at an indium electrode a reduction wave was observed at 045 V vs the Ir ORE which was reasonshyably well defined at a scan rate of 002 V sec This wave is due to Cr J reduction the wave height increased upon adding CrF 2 but did not change upon adding LijTe At our normal scan rate of 01 V sec the wave was not well defined which explains in part why it was not positively identified on background scans that are norshymally recorded at 01 V sec
4 Voitammetrk waves indicative of leilunde firms on a gold electrode were observed However these waves disappeared after adding CrFj to the melt The volt-ammogramlt recorded at gold foflowmg the L i 2 Te addishytions became complex and the electrode reactions are not yet resolved
Additional volrammeirr measurements are planned whereby the supposedly more soluble and stable LtTe species will be added to the fuel melt
igt 2$ c m 2 temperature M W C potential io le wilts s Ir QRF
ORNL-DWG75-11276
l _ _ J I I 1 bull 0025 0 -0025 POTENTIAL V vs U ORE
fSA Statpmry laquofctWodc to l lmdashuupaw for IW rwJt-timi of imKl l ) at a bullyrorytic gray laquonlaquouut InwfoMe prodshyuct j i 650 ( ibrnretH-jl Kp hbdquoi - 05 mV me-i-uired 3 0 mV InHMlll ctgtiraquocenirjiHgtn n02 electrode jrea 01 o n
so
C---+C S -raquoTS
TMpound
F-f57 Cycfc Hraquoi-o-i--uli bull gt bull y mdash l fat HJC rofactioti of mottlU M raquo etcmgt4e area 01 cm 1 -cmr-mare 650C potcnlbi - o k tuli VI Ir URF
-TIME
FomuiilT ot irondh iraquoiraquo
vt
w i l l
Ffc SJ Cydm ctmomtfottmtia^mm for r jrra n2 a n 1 po-rnlnl laquoale raquonltlaquo v Ir QRF
ft- bull v -
r of MMdl ) at i Formality of -rolaquo(llgt OfMVrfcctr-i-Jr
Part 3 Materials Development H fe McCoy
The main thrust of the mateiials program is the develshyopment of a structural material for (he MSBR primary ciicuit which has adequate resistance to embrittlemeni by neutron irradmion and (o shallow intergranular attack by fission product penetration A modified Hasteiloy N conoining 2^ Ti has good resistance to irradiation embnukment however it remains to be shown that the alloy has sufficient resistance to shallow intergranular cracking Numerous laboratory tests are in progress (o answer (his important question It may be necessary 10 further modify (he alloy with rare-earth niobium or higher chromium additions (o impait heller resistance (gt shallow intergranular cracking
Laboratory programs (o study Hasteiloy N salt tellurium interactions are being established including the development of methods for exposing (est mat era Is under simulated reactor operating conditions Surface-analysis capabilities have oeen improved so that the reaction products in (he affected grain boundaries can be identified
The procurement of products from two commercial hea(s 1000 and 10000 lb I of 2^ Ti modified Hasielloy N continued All products except seamless
tubing were received and much experience was gained in (he fabrication of She new alloy The products will be used in all phases of (he materials program
The work on chemical processing materials is concenshytrated on graphite Capsule tests are in progress to study possible ch-mical interactions between graphite and bismuth-lithium solutions and to evaluate (he mechanishycal intrusion of these solutions into the graphite Since (he solubility of graphite in bismuth-lithium solutions appears to increase with increasing lithium concentrashytion a molybdenum thermal-convection loop that conshytained graphite specimens was run to study mass transshyfer in a Bi 25 Li solution
Some of the effort during this reporting period was expended in reestablishing test facilities Four thermal-convection loops are in operation in the new loop facility which will accommodate at least ten loops The mechanical properly and general test facility is partially operational but numerous test fixtures remain to be assembled and tests started An air lock has been added to the general test facility to make it more functional and plans were developed partially for further expanshysion of the faclity
51
(x Development of Modifk-d Ha^tclkn N H t McCoy
The purpose of this program is the development of metallic structural material)) for an MSBR The current emphasis is on the development of a material for the primary circuit which is the must important problem at present The material for the primary- circuit will be exposed to a modest thermal-neutron flux and to fuel salt that contains fission products It is believed that a modification ot standard Hasteiloy N will be a satisfacshytory material for this application An alloy that contains y1 Ti appears to adequately resist irradiation embrittle-ment but it remains to be demonstrated that the alloy satisfactorily resists shallow intergranuiar attack by the fission product tellurium Small additions of niobium and rare earths (eg cerium lanthanum) to the alloy abo improve the resistance to shallow intergranuiar cracking and likely will not reduce the beneficial effect of titanium in reducing neutron embrittlement Increasshying the chromium concentration from the present 7T to a value in the range of 12 to 15 may also be beneficial in preventing shallow intergranuiar attack Currently factors associated with production of the 2T Ti modified alloy in commercial quantities are being studied while smaller be-ts raquoe being nude o( Hasteiloy N containing both 2 r Ti and additions of niobium and rare earths These materials are being evaluated in several ways
Two large heats one 10000 lb and the other 8000 lb of the ya Ti modified alloy have been melted by a commercial vendor Product shapes including plate bar and wire have been obtained for use in several areas of the alloy development program Tubing is currently being produced by two independent routes The various product forms from the two large heats are being used to fabricate the salt-contacting portions of two forced-circulation loops
Laboratory methods for studying Hasteiloy N salt tellurium reactions are under development Methods must be developed for exposing candidate structural materials to simulated reactor operating conditions Tests are being run in which specimens are exposed at 700V to the low partial pressure of tellurium vapor in equilibrium with tellurium metal at J00C Other tests involve metal idlundes thai are either added to salt or scaled in cvjcualed quart vus lo provide a source of tellurium Several experimental alloys have been exshyposed lo tellurium and Die extent of inlergranular cMltking was evaluated meiallograpliically hssenli^l In tins prltgram jrc attentate technique for identifying
and characterizing the reaction products Several methods for the analysis of surface layers are under development
Materials that are found to resist shallow intcrcranuiai cracking in laboratory tests will he exposed laquobull fissioning salt in the Oak Ridge Research Reactor TeGen fueled-capsule series Three materials (standard llastelloy Inconel 601 and type 304 stainless steel) were exposed in this manner during the first TeGen experiment and their cracking tendencies closely parallel those noted in laboratory tests in which these materials were exposed to tellurium vapor Fuel pins for a second experiment have been filled with salt containing gt J U and will be irradiated in the i a future
61 DEVELOPMENT OF A MOLTEN-SALT TEST FACILITY
H E McCoy K W Boling B McNabb T K Roche J C Feltner
When the MSRP was terminated early in 1gt73 most of the equipment was reassigned to active programs When the MSRP was reactivated a year later the conshystruction and installation of new equipment were necesshysary before testing could begin Balding 2011 acquired by moving the occupants into a siraquoaller building had been used as a mechanical testing area about 12 years previously and was already equipped with emergency power and air conditioning However numengtus imshyprovements ~n the building were necessary in addition to lb acquisition and placement of new equipment Although all of the equipment is not operational this report will describe the status of the facility
The building is a two-story structure with mnninal dimensions of 50 X 50 It The first floor is quite thick and more suitable for -mourning vibration-sensiiive test equipment The second floor is of lighter capacity and is more useful for offices and supoort activities There are Iwo stairways leadmg lo the second floor hut all heavy-items must he brought up hv an overhead crane which extends from the west side of the building The west wall had deteriorated and large doors leading into llie first-floor experimental area made close temperature control almost impossible An air lock having the dimensions 10 X W ft was added lo the west side of the building which greatly increased the buildings usefulshyness for experimental work An inoperabk emerge- puwei geneialor located in a small building on the cast
52
5
side or Building 2011 Mas removed and the space renovated to provide a small shop area
Figure 61 is a photograph of the west side of Building 2011 The air lock which was added is visible on the left-lurid side The crane lor transposing materials to the second f raquo)t is alsigt shown Figure b2 is a view of tllaquoe north side (ias storage racks the new emergency power generator and tie small shop area I left sulci are evident
Figure raquo slows the equipment layout tor the first floor Some of the equipment in the southwest owne is used by the Analytical Chemistry Division lor detershymining the concentration of oxygen in liquid-metal samples A neutron generator is located beneath the salt storage ar a and is used for oxide activation analyses This analytical capability is quite unique and will likely be maintained The 14 lever-arm creep machines on the north side aie for testing in an air environment the 8 machines in ihe next row are for testing in a sail envishyronment the Ji machines in the next row are lor testing bulln an air envirorment Five strain cycle machines are located in the southeast corner and will operate with
test specimens in j salt enviroiiVrctii Ihe temperature and strain readout equipment is centrally located Sail storage tjclitie and salt charging equipment are used ut conjunctii-n with he tests operating in salt environshyment S
The equipment layout on the second floor is shown m Fig o4 Six deui-Ioad creep machines for testing in an air environment are located on the south wall- The tube-hurst equipment is only partially instiled and lis installation is not considered a high-prioritv item Tie annealing facility consists of en furnaces having vartcux temperature and envingtnmental capabilities A separate laboratory in the northwest corner is used for experishyments involving tellurium llasieiloy N interaciiiws The other facilities on the second floor include offices a data storage and processing area an instrument repair shop and general storage
A view of iome of the 22 lever-arm creep machines for testing in an JH ermionmeni is shown tn l-ig t o and a cl-raquoeup is shmn in Fig traquofraquo All of these machines are in operation The control cabinet shown in Fig istraquo contains tlie insirunteKistion for two creep machine-
Photo 22SC-7S
yen 61 Mollrft-SjH Teraquol Faculty (RmMiof 2011) (mm Ihc wta ale The newly tiHUtrihled Jit lock bulllaquo mi the left
54
iJf JhZ
^bullyr^J^f1
Fifc J Matae-S TMI Ficttljr (Baliinj 2911) fjoraquo the monk ate Feature of interei include the hop area on he tt~ left the emenBencv pronator on the kft o s Morale rack in the center and the newly constructed air lock on the ri$h
iraquo now
I if(raquoraquo Kquipmcm layout for the fir floor of BudJinf ifll I
55
Fig fc4 EqnpncM Iqroat for Ifce Miomd Onor of IwMMg 2011
The frame is of welded steel construction The levei arms have two sets of knife-edge pivots vgt that the weight on the back of the arm is multiplied by factors of 6 or 12 The pull rods and cxlcnsometcrs are curshyrently arranged for testing small specimens having gage dimensions 1 in long by lA in in diameter Pull rods and cxtcnsomctcrs lor larger specimens required for code testing) were also fabricated and can be used in the same machines
The specimen deformation can he determined by the dial gage or by a transducer which measures the deflecshytion of the dial gage shaft This transducer signal is conshyverted to a dc signal by the instrumentation in the bottom of the control cabinet cm the right (Fig 66) and is printed at another location The electronic circuit will also accommodate averaging transducers which will be used on more precise code work The instrumentashytion in the bottom of the control cabinet also has a module for measuring load from a load cell (not shown) which Tils in the bottom on (he creep machine The specimen is heated by a resistance-wound furnace
having a maximum Icmpcraturc capability of I200C The temperature is measured by up to four Chromel-Alumd plusmni accuracy) thermocouples treated at various positions on the ipcimcn gage kngth The signal fron one of these thermocouples is used by the Leeds and Northrup type KO proportioning controller to control the furnace temperature Switches within this unit activate an alarm shown in the upper left coiner of the control cabinet (Fig 66) if the temperature varies more than plusmn6degC from the control temperature This alarm unit activates a local light and bell alarm as well as causing an alarm t gt sound in the Shift Operations Office A second thermocouple is tied to an over temperature monitor (lower left side of control cabinet in Fig 66) This monitor is set 10 to I5degC above the control icmp-rraturc arid will interrupt power to the furnace The monitor must be reset manually The furnace is powered by a solid-slate power supply deshysigned by T Hulton of the Instrumentation and Conshytrols Division The unit incorporates a digital Variac which allows power settings of 0 10 25 SO 75 and
56
FlaquofcS i t f
100 of line voltage Power is pulsed through the unit as called for by the Leeds and Northrop controller
The six dead-load creep machines on the second floor are quite similar to the lever-arm creep machines just described As shown in Fig 6 7 these machines r e not in operation but the construction work is com| iete Since the load is applied directly to the bottom of the specimen the equipment is limited to specimen stresses of about 20000 psi However the frames can be conshyverted to the lever-arm type
Two salt environment creep machines are shown in Fig 68 The frames and control instrumentation are the same as for the air environment machines shown in Fig 66 The primary modification is a stress unit which can be immersed in salt Four load-bearing rods run from the bottom of the specimen to a flange near the top of the frame A rod from the lever arm passes through a seal in the flange to the top of the specimen Thus weights placed on the back of the lever arm place the specimen under tensile stress with the pulling force being transferred back to the flange No rods protrude
far below the bottom of the specimen and a salt conshytainer can easily slip over the stress unit This container seals against the underside of the flange Extensometer rods for measuring the strain pass through seals in the flange and strain can either be measured by a dial gage or a transducer A 4-rn-diam furnace fits over the salt container There arc several openings through the flange into the container for gas lirtes and ball valves for elecshytrochemical probes and for making additions to the salt Figure 6deg shows the salt-creep machine which is in sershyvice The salt raquoas transferred into the pot on the right in the salt preparation facility at Y-12 The transfer pot was placed in a furnace after which the transfer pot and the receiver vessel were heated to about 600degC before the salt was transferred by applying argon pressure to the transfer pot The temperature was stabilized in the creep chamber and a strejs was applied to the test specshyimen
One of the five strain-cycle units is shown in Fig 610 The test specimen is a l-in-OD tube with a reshyduced gage section having a length of I in The tube is
57
Flaquo 6A CkMtmp of two Mr-
welded in place and stressed by a rod which extends from the bottom of the specimen to a piston above the specimen The piston s moved by applying air pressure to either side resulting in a tensile or compressive force on the specimen The specimen assembly is immersed in salt while it is being stressed Extensomeier rods extend through the top flange to measure the strain These rods move transducers whose signals are recorded on the bottom instrument Switches inside the recorder can be
adjusted to change the stress from tensile to compresshysive when the strain reaches certain values The test can also be controlled on a time basis and the strain reshycorded Other modes of control are also possible This type of test is to study the rate of crack propagation through thin-walled tubes of varying composition in the presence of tellurium Installation of the equipment has been completed and test specimens are welded in place The tests will be started as manpower becomes avail-
raquo
ask Thear mdashaAntv war be ased for aftojr and ame precise work w be done oa MTS e war arm to be procared at a later dale
The anai jau colectioa station h oa fLe first lloor (Fig 611raquo The apper part of the cabiaet OR die left cuMtaatt snitches a aiaiial readoat aad a snaje poiat recorder lor leraperatnres from avow one-third of dK machiaes- The haak of Mriicbes ia the top of da rajfct-haad cabinet is for tetecrinc siraia rawerraquo for each
The sna-i tcadaajs faaa each auduae arc priated oat oa oae of the andtipoiai recorders A data
M I is located m the aaodfc of the right-I cabiaet Has rnsmMKM ltai print oat 100 points
oa dK designated Ireqneacy (asaaly I br) This is snf-fcieat capacity to print oat oae teaaperaiare aad one
for each piece of eqai|aarnt Two orjer bulleasnriag stations are located elsewhere on
dK first floor
Ffct7 General
59
The annealing arez sun the second floor I Fig 612) The two furnaces on the lower level have environmental control and are used for short-term anneals Eight other furnaces are used for long-term anneals hi which the samples are encapsnlated
Figure 613 shows a typical area in tne second-floor laboratory wed for tdurtum-HasteBoy N studies The
equipwunt includes a quartz encapsulation apparatus special gradient furnaces for annealing the capsules equipment for measunng gas-metal reaction rates and a general-purpose hood
The ttthe-burst equipment boa die second floor (Fig 614) There are nine test stations with each station
four test |
Fin 68 Close-up of two bullut-eiwuuinwtnt lever-arm creep machines The salt chamber on the left-hand machine seals apinst the horizontal flange and the furnace n raised a proportionate distance The temperature control and strain-measurement instrumentashytion are shown on both sides of the creep machines
60
Ffe 69 Lever-arm jd l imnunmiiit creep NMCJMMS in operation The ult chamber and furnace have been raised calt as transferred by argon pressure from the vessel on the right into the test chamber The cabinet on the left contains switching and temperature readout instrumentation for several creep machines
61
FlaquoIO ChwMip of a a l l ltngtJKinmml strain cycle machine M l amocMni intfnjmvntation The ieraquoi specimen is a l-m-diam lube welded on I he bottom I a rod and un ihe lop to a heavy-walled lube The rod passes through the lube and alicrnaling tensile and compressive stresses are impigtsed on the specimen by ihe actuator (piston-cylinder combination) The instrumentation is used to control and record the sires strain-time history
bull2
F g 61 I The cabmct on Ike left is one of smraf tartowt stations for limptnmn Chrontd-Alumel sensors from seYeral creep machines arc ran to this cabinet The switches make it possible to read each thermocouple individually on the digital unit at tlie lop of the cabinet One point at a lime can be recorded on the Azar recorder The cabinet on the right contains a data logging unit for recording strain and temperature on all the machines on the first door The three recorders in the bottoms of the two cabinets record strain data from a l machines
a
fit- 612 tkotopajk of hcsMltsaag facfvty The two lower furnaces have com roikd argon environments Fighl other furnaces (al noi visible) have air environments and are used for long-lime anneals
64
Fig raquo13- Typical vie of geaoat-aeaaot used to dean salt from jpuiawai tested in a l t amroameati
ettl reactroas The hood on the left is
rraquoraquoiraquo wraquo-raquo
F|g 614 General view of tube-burst testing eqaipment asai lo stress tabular spec ant ni by internal pre ware The front paneli contain only (he pressure-related equipment The furnaces where the test specimens ate located and their associated control instrumentation are behind the pressure panels
65
by a pump with a wear pressure of 14400 pa The pump aad the ass-xiated reservoir cylinders have beea approved for opcratioa aad the iaawaaal test suborn w2l be pat irt semcr oa c ow-pnonty basis
Iiiaatdun efiptens wtfJ be placed oa geinaf a l equipment iato operatioa Longer-term objectives war iadade prucaremeat aad iastaaatioa of an MTS fatigue machine aad possible expansion of the fast floor to accooaaodaie additioaal creep machines
t J PROOJKEMENT AND FAMUCATION OF EXHHMENTAL ALLOYS
T K Roche R E McDonald B McNabb J C Fehaer
bullUI hadwit iaaHeatsafraquo Ti M I T I I I M H I I J N
One of the more promising alloys at present for the primary circuit of an MSBR is 25 Ti modified Hasidloy N Progress has been made in the scale-up of this alloy with the production of two large heats one 10000 lb and the other 8000 lb by a commercial vendor The analysis of the heats was reported preshyviously These heals were used to establish processing parameters for producing plate bar and wire and more recently emphasis has been placed on processing seamshyless tubing Mill products from these heats are being tesed in the general alloy development program and used in the construction of two forced-circulation loops for studying the compatibility of the alloy with fuel salt
As reported previously several fabrication problems were encountered with the first heat (heat 2810-4-7901 or 74-901 10000 lb) in that it was prone to cracking during hot-working operations particularly during hot rolling of the plate However with the aid of Glcebli evaluation tests which defined the hot-working temperashyture range of the heat to be between 1090 and I I77degC plate products were successfully rolled A second prob-leri was the susceptibility of the heat to cracking during the annealing treatment following cold drawing in the production of bar and wire products This problem was partially solved by cither flexing the drawn product in straightening equipment prior to aiiiltjHijat 1 7degC or by lowering the intermediate annealing temperature to nidegc
Because a considerable amount of the first heat wis consumed in establishing processing parameters a
I T K Roche B McNabb and I C FeltrwrMSK Proshygram Semmrmu Pmgr Rep Feb 2 1975 ORNL-5047 pp 60 63
second heal was prodaced (hat 8918-5-7421 or 7S42I 8000 lb) for coavcrsioa to tatang bar and wire The bot-forgaag behavior of das heat was qaite good as confirmed by Cfeebie data which showed a very broad bot-workmg temperature range of 930 to 12600 Approximately one-half of das heat was forged and tamed to 4 Jna-diara bar for coaversion to seamshyless tubmg by the vendor Akoa forged bar 4 X 4 X 6 0 in was produced for conversion so tabiag by an altershynate route The balance of draquoe heat was convened to the folounac products which bat been received o-m-diam bar (630 lb) 05-ai-diaai bar (292 ft) 0J12-in-disn bar (996 ft) 0125-av-diaai wire (405 b) and 0-094-in-diam wire (338 lb)
For making products in the range ^-ia-diam bar through -in--diam wire forged bar was hot roBed to about I-ia-diam bar and an attempt was nude to conshyvert this material by cold drawing to final sizes with intermediate annealing treatments This routing proved satisfactory unti a H^meter of 0J95 in was reached but annealing cracks as experienced with heat 74-901 were encountered to some degree during processing of the 03l2-tn-diam bar and the wire products For example during a run involving about 850 lb of stock about 2 of the product was lost due to cracking during annealing after the material was drawn from 0J95 in in diameter to 0 J i 2 in in diameter The bar was mechanishycally flexed prior to annealing a technique used to minimize cracking in material from the first production heat of the alloy (heat 74-901) The annealing cracks were observed to run parallel to the longitudinal axis of the bar Examination of a transverse section of the cracked 0Jl2-in-diam stock showed that the cracks were intergranular in nature and up to 0065 in deep in the section examined (Fig 615)
It has been possible to reproduce the annealing crack phenomenon on a laboratory scale Samples of 05-in-d am bar of each of the two production heats were coiJ drawn lo 0395 in in diameter (37 reducshytion) and annealed at I I77degC Heat 74-901 developed longitudinal cracks heat 75-421 did not These results are consistent with the vendors observation that heat 74-901 is more susceptible to the cracking problem Since the cracking can be reproduced or a laboratory scale it may be possible to more fully characterize the problem and define fabrication parameters necessary for its prevention
Of the two routes being pursued for the procurement of seamless tubing one by the commercial vendor inshyvolves trepanning forged and turned bar slock to45-in OD X 05-in wall cold tube reducing (or pilgering) the material in three steps to 20-in OD X 0187-ir wall
66
m
o p A
-O o_ b
o x t o 1 yraquo2
o o-
8-o
yen $ H m d i raquo cocks iraquo ttJU-aL-MMi bat of 2raquo T t - a o M M KasMftty N (hut 75-421) Bar was coM drawn 37- and ameafcd a( I065C Ftdicd with (dyccm rrpa 50x
followed by cold drawing to final sues of 10- 075- 05- and 0J77-in OD X OJ035- to OX)72-in wall This route for tubing production depends upon the efforts of two other vendors one for trepanning the bar and the other for drawing to tlnal sizes The trepanning operashytion has been competed and resulted in six tube holshylows each approximately 6 ft long Each of these pieces was processed through the first tube reducing pass to a 375-in OD X OJ75-in wall (3675 reduction) with no difficulty From this point work was confined to one tube hollow to determine its response to in-process annealing at I I 2 I degC and water quenching followed by further tube reduction Annealing of the hollow beshytween each tube reducing operation was preceded by the annealing of a sample which was then liquid penetrant inspected to determine any evidence of crackshying With this procedure the hollow was taken through the remaining two tube reducing steps and three annealshying treatments with no major problems A few shallow surface flaws did develop but these were readily condishytioned from the product Therefore on hand at present is approximately 24 ft of 20-in-OD X OI87-in-wall stock which will be scheduled with the redraw vendor for processing to final sizes The lube reduction of the remaining five hollows will also proceed
The second route for obtaining seamless tubing inshyvolves hot extrusion of tube shells at ORNL followed by cold drawing to size by an outside source Starting stock was the forged bar of the alloy 4 X 4 X 60 in (Fig 616) The bar was machined into six billets each of which measured 3deg50 in in OD by approximately 95 in long and had a 45 tapered nose for extrusion out of a 4060-in-diam press container through a conical die Two of the billets were drilled 0812 in in ID and four were drilled 10 in in ID to accommodate a mandrel and to allow for a slight variation in extrusion ratio A glass coating which was molten at the extrushysion temperature was applied to the billets and served as the primary lubricant Additional lubrication was provided by Fisk-604 grease that was applied to the tooling Five of the billets were extruded at 1200degC and one at I250degC Low extrusion rales (ram speeds) were used to prevent a sufficiently large temperature increase that the incipient meiing temperature of the alloy would be exceeded otherwise serious cracking could result This problem was encountered during the develshyopment of standard Hastelloy N but was solved by conshytrol of extrusion rate
The results of extruding the l7r Ti modified HaMclloy N billets in the order performed are pre-
67
sensed in Table ftI Fur the first three tube blanks produced extrusions lottf 104 and 1605) die low rale of extrusion caused mandrel taawre d w to ecev I I K healing vf the tooling However ike length of tube blanks obtained with various extrusion ratios and ram speeds suggested that the combination of tooling used lor extrustoR 1604 (extrusion ratio of deg41) with an extrusion speed approximaidy equal to that of extrushysion 1605 125 m sec) should produce a complete tube blank This was die case for extrusions I60K and I6QN In an attempt to reduce the force required to make these extrusions the final tube blank lexirusion 1611)
was extruded a a slightly higher temperature 12501 A rather long length ol good extrusion was obtamed but mandrel fanure agam occulted due to the low extrushysion speed
Visual inspectioK of die tube blanks showed die OO surfaces to be quite good as must rated m Hg 617 wfwch shows the lesdmg end of extrusions I60K and 160V O i dae other hand boroocopic examination ol the IDs by die outside vendor performing the redraw operation revealed flaws winch were subsequently removed by gun iriEing These flaws shown typically in Fig 618 a=e believed tc be caused by inadequate lubn-
m-n
Flaquo l seamless tuctnc
H r ( lt 4 gt M u i r K T i - i N (fecal 75-42 h Slock for ramm bwVt o produce
Tafefc-tl snd raridof n w Mask cxtrwOTMvav2t Timdashnodinnl Nattdby N (beat OTI8-5-Mll|(B
Fxtruuon Die diameter i in i
1603
1604
1605
i475
1625
1475
Mandrel dumcrrr
in)
K IruMt-n Rjm speed ratio (in laquo i i
Force ttonsi
Maximum Running itesuils
0813
JO
0812
114
94 I
1041
15
15
25
1230 l l l l Good 0D surface 22 m of tube blank extrusion before mandrel fadure
l6igt 1100 Good OD surface 45 in of tube Hank extrusion before mandrel fadure
12f0 12i Good Oigt suriacc 4raquo in of rube blank extrusiim before mandrel failure
1607 1625 10 941 Stalled operational error
1608 1625 10 941 36 12911 1290 Good Ol) surface 70 in lube Mank extrusion
1609 1625 10 941 36 1290 i290 Good OIgt surface 70 in tube blank extrusion
1611 1625 10 941 10 1000 900 Repeal of extrusion 1607 jtood OD surface 55 in of lube Hank extrusion before mandrel failure
Notes Container diam 4060 in hxtrunon temp 1200deg (except extrusion 1611 at I250C Lubrication class on billets f-isk-604 jcrease on tooling
68
nraquolaquo15M-79
M06
760 Fig 617 Tibr hlanfc exuasjom of 2 Ti-wdifM I fuWuj N (heal 75-421 These are ihc leading ends or the two extrusion
and were photographed in the as-extruded condition
O O-
O O-
O ho d
Fig 618 Typical defects M I the made diameter of extruded lobe Wanks o 7 Tr-modifod rlartcBoy N (heat 75-421) Longtludinal section Ffched wrlh glyceria rejtia tOOx
69
cation during extrusion Therefore several additional extrusions are planned to test ihis assumption and to evaluate other lubricants The bilets will be prepared from the 6-in-diam bar fabricated from the same comshymercial heat used for the previous bitten
The products of the six extrusions (Table 61) were sent to an outside vendor for redrawing to finished tubing More effort was required than anticipated due to several factors the conditioning required to dean up the surfaces of the extrusions experimentation with both plug and rod drawing techniques to establish a workable processing schedule and more frequent and longer intermediate annealing treatments than anticishypated for the alloy The vendor believes that a satisfacshytory drawing schedule has been developed and is proshyceeding with processing of the remaining extrusions The vendors preferred process involves rod drawing and sinking operations requiring about 18 to 2ttS deformashytion per pass with intermediate annealing treatments at I I77C followed by water quenching Quality control steps after each process step irJ-de light etching folshylowed by visual inspection of the OD and boroscopk inspection of the ID for defects It is believed that the yield of tubing from the redrawn ORNL extrusions will be sufficient for at least one of the two forced-circulation loops now under construction
A 6-tt length of cold-worked 075 m-OD X 0072-in-wall tubing was received as product from the development work required to establish a drawing schedule The tubing is being evaluated by nondestrucshytive techniques Liquid-peneirant inspection of the OD showed no defects Silicone rubber replication together with radiographic inspection indicated the presence of relatively shallow crackiike indications on the I D over a 4-ft length Meiallographic examination of a small sample from the did of the 6-ft section showed the defects to be J maximum of 0028 in deep The tube will be annealed and inspection will be repealed including examination by an eddy-current technique In view of the number of process variations to which the tube was subjected in developing a drawing schedule the quality of the OD and that of portions of the ID is encouraging
622 Seimprodlaquoctiontfeatsof2ri-Modified Hastdoy N CoiriaMng Niobium
To provide stock for a more complete characterizashytion of niobiunviiianium-modified Hastelloy N eight SO-lb heals and one 2S0C lb heat (Table 62) are being prepared by a commercial endor Niobium additions lo the 27 Ti modified Hasieloy N base arc of interest for enhancing resistance to tellurium embritilemcnt and
Bve Ni-12T Mo-7laquoS Cr-21 Ti-007 C
l ov Addition of the jadiciied rirMear 4) Heat
laquoze lltraquo
Jmr re Si Ma Nb
Heat laquoze lltraquo
i 10 01 02 085 -115 2500 10 01 02 04 06 50 IO 01 02 135 -165 50 10 01 02 18-22 50
30 50 01 02 085 11$ 50 10 01 - 02 02 085-115 50 10 01 02 05 085 115 50
8 30 50 01 02 02 -05 085-115 50 bull 10 01 02 085 115 50
Indrndnl nines denote maxnnom coaceMnrioa
niobium levels between 05 and 2 wt It w i l be investishygated Ir addition the compositions of four of the alloys were chosen to investigate different levels of the residual elements Fe Mn and Si These results will be important because of the beneficial effects of the residshyual elements upon oxidation resistance and will allow greater latitude in scrap recycle
The nine alloys have been melted and will be procshyessed lo products in the near future The eight 504b melts will be forged and rolled to ^-in-thkk plate approximately 4 in wide This material will be used for voidability salt corrosion tellurium compatibility and mechanic property tests The 2500-lb heat will be conshyverted to t |raquo- V - and | k-in-diam bar products and to a 4 X 4 in round-cornered square bar About half the material will he retained in the last form lo allow future capability for producing additional products of sheet bar and tubing
6 J WELDAMLITY OF COMMERCIAL ALLOYS OF MODIFIED HASTELLOY N
B McNabb H E McCoy T K Roche
Welding at ORNL is generally performed in accordshyance with Section IX of the ASME Boiler and Pressure Vessel Code2 Basically this requires that a procedure for welding a material (or class of similar materials) be developed and that welders demonstrate that they are qualified to weld by the procedure The procedure must
2 ASMt BoHer and Pressure Vessel Code Section IX Qutt ifuvxm Standard for Welding and Braimg Procedures Weldm Bnm end Welding and Brtittg Operators American Society of Mechanical Engineers New Ywk 1974
70
be a written document including die essential variables associated with making the weld and must be backed by test reports including bend and tensile tests which show that the weld is sound A welder can then be qualified to use die procedure by making a weld which is subshyjected to bend tests to show that it is sound This is a very suupKfied view of the process used to develop and maintain high welding standards and the ASME Boiler and Pressure Vessel Code Section IX 2 should be conshysulted for more detal The Plant and Equipment Divishysion main tains a weld test shop under the supervision of D R Frizzed to implement the process and this shop is frequently assisted by the Inspection Engineering Department
Procedures were previously developed for joining HasteHoy N to Hastdloy N (WPS-1402) and Hastettoy N to die austemtk stainless steels (WPS-2604) but it was necessary to demonstrate whether these procedures apply equally weO to 2 Ti-modified HasteBoy N Therefore K-n-thkk test plates of 2 Ti-modified Hastelloy N (vendors heat 2810-4-7901 designated ORNL heat 74-901) were prepared and welded as folshylows autogenous welds with 74-901 welJ wire welds with 2 Ti-modified Hastelloy N weld wire (vendors heat 8918-5-7421 designated ORNL heat 75-421 welds to standard Hastelloy N heat Nl5075 with 2 Ti-modified Hastdloy N heat 75-421 weld wire and welds of type 304 stainless steel heat 18024 with Inco 82T heat NX59I38-D wdd wire Each raquo d d was subshyjected to visual dye penetrant x-ray and metallo-graphic ixr^mation and to two tensile and four side-bend tests These tests were conducted in accordance with die ASME Boiler and Pressure Vessel Code Secshytion IX 2 and ail of the above-mentioned welds passed the tests The tensile specimens were machined from the test plates with the weld in the reduced-section gage length and were tested in a Baldwin tensile machine All Hastelloy N welds exceeded the required minimum 100000 psi ultimate tensile strength except the weld of 1 Ti-modified Hastdloy N to type 304 stainless steel which ruptured in the type 304 stainless steel base metal at 93300 psi The side-bend specimens were A X li X approx 8 in long with the weld in the center and were bent around a I-in radius in a guided bend fixture
The chemical analyses of the various materials involved are shown in Table 63 The side-bend specishymens are li in (luck X hi in wide bent around a l-in-radius mandrel in a guided bend test The specimens were macroetched in a solution of HO 20 HNOj -20 H 2 0 to delineate the weld and heat-affected zones Figure 619 u a macrophotograph of side-tnd specimens of standard Hastelloy N heat
N1-5075 Vi-in-thick plate welded with standard Hastelloy N wdd wire heat N I -S I0 I There were no fiows in the specimens after bending and visual dye penMrant x-ray and mrtallographic examination before bending showed that the welds were sound This weld was inde and tested to recertify the welder and to update the welding procedure specification Figure 620 is a reacTophotograph of side-bend specimens of 2 Ti-modified Hastelloy N (top) (heat 74-901) welded to standard Hastelloy N (bottom) (heat N1-5075) with 2 Ti-modified Hastelloy N (heat 75-421) weld wire by welding procedure specification WPS 1402 There were no flaws in the welds and the strain markings delineate the weld areas
Figure 621 is a macrophotograph of 2 Ti-modified Hastelloy N plates (heat 74-901) welded with 2 T i -modilied Hasteiloy N (heat 74-901) weld wire on weldshying procedure specification WPS 1402 There were no flaws in the welds and the specimens were macroetched to delineate the weld areas Figure 622 is a macro-photograph of the same heat of 2 Ti-modified HasteBoy N (74-901) welded with 2 Ti-modified Hastelloy N (heat 75-421) weld wire by specification WPS 1402 There were no flaws in the welds and the specimens Figure 623 is a macrophotograph of side-bend specimens of type 304 stainless steel K-in plate (heat 18024) (top) welded to 2 Ti-modified Hastdshyloy N (heat 74-901) (bottom) with Inco 82T (heat NX 59138-D) weld wire by welding procedure specification WPS 2604 There were no flavs in the welds and the specimens were macroetched to delineate the weld areas
Although special welding procedures were prepared for the joining of standard to 2 Ti-modified Hastelloy N with 2 Ti-modified Hastelloy N filler wire (WPS 1403) and for joining stainless steel to 2 T i - modified Hastdloy N with Inco 82T filler wire (WPS-2606) the parameters used in making these welds were identical to those used in procedures WPS 1402 and WPS-2604 developed for standard Hasteiloy N Thus we believe that the test wdds adequately demonstrate that stanshydard and 2 Ti modified Hastelloy N have equivalent welding characteristics and that procedures WPS 1402 and WPS 2604 can be used for both materials
Supplies of standard Hastelloy N weld wire were depleted over a period r f time and additional wire was purchased to the materials specifications MET-RM-304B However the voidability test was performed by O R N L Plates of standard Hastdloy N (heat 5067) IV t
X 4 X 10 in were welded with the new heat of weld wire from Teledyne Allvac (heat 9725) using welding procedure specification WPS 1402 and were accepted
71
Jiilln l i s i l
1 3
3 laquo m i a m I z
llllpl liillii s a = c e e v
i
i
I I I
Hill s s = s e
Ii2s I
I bull raquo bull
S C O
33 a c e o 3 O m
i
bull mdash copy o r- d 9gt
laquobullraquo bull gt ampgt ltlaquo rraquo laquo r i mdash
1 laquo
z z z
r t a laquo m r- f 2 gtgtilti bull laquor mdash H-
2 2
i ij
72
Ffcfc1 Bead N(heMNI-S075)j Htmuwwtt SIM)
Ffe gtJ0 I M 4 ffcciMtM of 2 T t - m o t f M HmHtoy N (fctrt 7901) art staataaJ H n M o r N (fcMNI-5075) j o M w M i Tt-modiTM Hartdoy N Mkr win (beat 75-421)
73
F laquo J I (heat 74401)
Ffe 622 ttmt (raquotat 75-421)
of J Ti-motfbJ HMcltoy N (beat 74401) f o M wMk 2 Ti-amtttM
74
FlaquoftJ3 i01 tyyc39v 3 I H T H N ( laquo laquo 7441) j IwMUTflkr
as passing all tests including one all-wdd-inetal tensile test and four side-bend tests with no flaws in the welds This material has been made available for general proshyject use
4 STAWLrTY OF VARIOUS MODIFIED HASTEIXOY N ALLOYS IN THE
UNIRRADIATED CONDITION
T K Roche H E McCoy J C Feltner
The stability of Nb- Ti- and Al-containing modified Hastelloy N with respect to intermetallic predpitation known as aging is being studied It is known that addishytions of these elements are desirable respeclivdy for enhancing resistance to tellurium-induced intergranular cracking for improving resistance to radiation embri-tlement and for deoxidizing the alloy during melting However beyond certain levds these dements can cause aging reactions by the predpitation of gamma prime |Nij(AITi)| or NijNb which in turn causes hardening or strengthening and loss of ductility Therefore studies are in progress for defining the amounts of Nb Ti and Al which can be added to Hastdloy N and still maintain a reasonable decree of stability The stabilities of a number of alloys including laboratory semiproduction and production heat having varying amounts of the
demenu in question are being determined by hardness tensile properties creep-rupture properties and micro-structural evaluation
The first approach to evaluating stability has been the determination of the room-temperature hardness of the various alloys before and after heat treatment at 650 704 and 800degC for periods up to 1000 hr The data for alloys held at these temperatures for 100 hr were reshyported previously1 and during the present period the 1000-hr data presented in Table 64 were obtained he data for alloys which show significant hardening relative to the as-annealed condition are Mocked off in the table
The hardness of the various alloys after a 1000-hr aging period follows the same pattern noted for the 100-hr aging period However the previously reported niobium concentrations of the niobium-containing alloys were low due to an analytical error the correct values are shown in Table 64 The present data show that with low aluminum concentrations (00S wt ) niobium contents approaching 2 (rather than as conduded earlier) can be tolerated in 2 Ti-modified
3 T K Roche D N Braski and J C Felfnrr MSK Pro-gum Semmnnu fmgr Rtp Feb 2S 197$ ORNL-5047 pp 71 76
75
lkra llaquoMi7WMri l
DatamMoriui hatdcMBg rcbthc to the
Icoaditiw
IoapoBtun (laquot ) Rockwell
Heat IoapoBtun (laquot )
AaaeaM (
Agt4 1000 were 704c
hr Nb Ti Al C AaaeaM
(
Agt4 1000 were 704c sooc
474-557 214 002 004 SI 5 S7S SSS S74 472-503 194 009 006 S44 S9S 882 891 474-901 IS 010 006 794 857 S63 856 471-114 1- 012 005 792 829 846 S44 427 24 0IS 0014 747 784 773 779 428 247 016 0064 S25 SS2 861 860 474-533 217 04S 005 Sl0 857 S62 849 474-534 209 053 008 893 925 904 909 429 24 0J5 0017 769 9 4 854 74 430 25
2J 034 074
0073 0016
SS6 7S6
1001 88 9 912 431
25 2J
034 074
0073 0016
SS6 7S6 978 984 928
432 048
235 19
069
008
0057 0037
874
SOI
1034 1034 974 425 048
235 19
069
008
0057 0037
874
SOI 841 858 852 421 10 19 007 0048 873 865 878 867 424 134 I S 010 0063 S84 902 SS9 904 418 192
190 20 18
005 015
0058 0055
891 S87
904 900 9IA
904 420
192 190
20 18
005 015
0058 0055
891 S87 1015_
900 9IA 913
435 142 23 015 004 886 1050 1021 903 43S 180 24 013 005 918 1066 1051 968 433 189 2 2 033 0024 848 1043 1021 881 434 186
252 2 bullgt
22 032 015
0061 005
933 931
1070 1088
103 8 1076
957 441
186 252
2 bullgt
22 032 015
0061 005
933 931
1070 1088
103 8 1076 1041
442 30 22 014 0052 950 1093 1096 1072 30 22 014 0052 950
Bavt Ni l2TMo K Cr l h r j | IMTC
Hastdloy N before aging occurs However the tolerance for niobium decreases with small increases in the titashynium and aluminum contents It must be emphasized thai the hardness data were obtained on unstressed specimens and that creep-rupture tests now under way indicate that lower concentrations of niobium are tolershyable when the alloys are subjected to stress These reshysults arc described Uter in this section
The effect of aging on room-temperature and elevzed-tempcralure tensile properties is being detershymined for most of the alloys Limited room-(emperalure results have been obtained after a 100-hr aging period at 650 and 800degC (Table 65) There is good correlation between the tensile data and the preshyviously reported hardness data As would be expected alloys which age harden during a given thermal treatshyment (data underlined in Table 65) also show an inshycrease in strength and a corresponding decreur in ducshytility relative to ihr solution-annealed condition
In the case of the tiunium-aluminum-modified Hastdloy N alloys the hardening phase is most likely gamma prime and this phase has been identified in heat 430 lt 25^ Ti + 034 Al) after 100 hr at 6 5 0 o C
Stress-rupture results for the titaniunvaluminum-modified Hasielloy N alloys at 650 and 704degC are shown in Tables 66 and 67 respectively Again there is very good correlation between age-hardening behavior as determined from short-term hardnlaquo data and the corresponding rupture life in the stress-rupture tests Abo the effect of temperature upon agmg an be seen by comparing the data sets for heats 429 and 430 at 650 and 704degC At the lower temperature both of these alloys hardened but neither hardened at 704degC Since hardening in these alloys is due primarily to the formashytion of gamma prime these results sugges that the gamma prime solvus temperature is located between 650 and 704degC for these two alloys This observation and the other aging data in Tables 6465 and 66 were
76
Tak6-5 raquo i m l all l i l i h t i i i i i i fci iwfNJ-TVAI
iicbtaKtodK
bdquo laquo t t m t ~ - - - StteaajbUO neat _ ^ _ ^ ^ _ _ _ _ _ _ ^ ^ ^ _ _ l o a a m _ ^ _ ^ _ _ _ _ _ Doaaaboa ()
iraquo r At c mum Y j - i ^ ^ 474401 18 010 00 AnwaM Ikr l 7 r c I MO 442 447 794
Aaoil00br50C 114 J $00 559 SIS Aged 100 brS00C I I9JO SI2 537 151
428 247 0 1 00 A a w a M l k t I I 7 T C 124 J 49-0 52 825 Aged 100 br50C 125J $0-5 527 M2 Aftd l0fgtbrS00C 1237 511 411 M7
430 2J 034 007 Aaneakdlbf I177C I2SJ $00 541 St Aac4IWbr5ltrc 1348 634 437 957 Aged 100 brS00C 12 J 531 $00 886
424 134 I a iO 00 AMtafcdlbr I177C 1372 527 512 Ago i00br6$OC 1385 52J 477 (93 Aged 100 brSO0C 1377 547 45S 199
435 142 23 015 004 Aaaeakd 1 hr 1I77C 12S4 510 54 raquo Aged 100 br50C 190 893 353 1025 Aged l00brSOOC 1339 54-5 S3S laquo73
442 30 22 014 003 Aantakd 1 hr II77C 1394 07 $42 Agadl00bf50C 1905 107 251 AftdlOObrSOCTC 144 ~ J 3 J 1 S 9
bull raquo Ni-12 Mo-7 O
TaMe64 St iwiaptmdashe data for wr iow beats of Nb-Tt-AI R M d M H a s t d b ^ N at 6500 aad 474) x I0gt pa
Heat Composition (wt gt Rupture
life (hrgt
Total strain
Are harden Heat
Nb Ti Al C
Rupture life (hrgt
Total strain at 650deg C
474-901 18 010 006 3950 270 No J74-533 217 048 005 4650 280 No 427 24 118 0014 866 217 No 428 247 016 0064 1150deg 73 No 429 24 03laquo 0017 9572 163 Yes 430 25 034 ftO^ 16980 73 Yes 431 2$ 074 0016 23090 101 Yes 432 235 069 0057 41710 21 Yes
42S 048 19 008 0037 14301 237 No 421 104 19 007 0048 20070J 73 No 424 134 18 010 0063 39530 65 No 418 192 20 005 0058 39550 32 No 420 190 18 015 0055 39510 19 Yes 433 189 22 033 0024 41690 10 Yes 434 186 22 032 0061 39550 09 Yes
BaseNi 12 Mo 7Cr Based on turdnest measurements on aged umircutd specimens Tesl still in progress Test discontinued prior to fracture
used to estimate the gamma prime solvus temperature boundaries at 650 and 704degC as a function of aluminum and titanium concentrations Alloys with compositions lying below the proposed boundaries in Fig 624 are stable at the indicated temperature and those above will precipitate gamma prime
With the addition of niobium to titanium-aluminum-modified Hastdloy N defining or predicting stable comshypositions becomes more complex There is evidence1
that mechanical stress significantly affects age hardening of these alloys which is not uncommon The room-temperature hardness data for annealed and aged specishymens of the various Nb-Ti-AI modified Hastdloy N alloys suggest a tolerance of about 2 Nb in a 27 Ti-0-5 Al modified Hastelioy N base (heat 418) beshyfore aging occurs Further increases in the aluminum niobium and titanium contents lead to age hardening at 650degC then at 70degC and finally as high as 8O0degC when the niobium content is increased to about 25 with 22 Ti and 015 Al (heat 441) If the broad assumption is made that the three elements are equally effective in promoting an age-hardening reaction and a plot is made of the total atomic percent of these deshyments (at Nb t Ti + Al) in the various alloys against the increase in hardness (^RBI caused from aging 1000 hr at 650degC a curve is obtained (Fig 625) A sharp break indicative of appreciable aging occurs between 3H and ^M at 1 (Nb + Ti + Al) Adding the variable of stress to aging response and plotting the parameter of minimum creep rate from creep tests at 650degC and 470 X I0 3 psi (Table 68) against total atomic percent (Nb bull Ti + Al) results in the curve shown in Fig 626 The break now is indicated between 2 and J at (Nb + Ti bull Al) The creep rale of alloys containing up to about 2 at rlt (Nb bull Ti + Al) is 15 to 30 X lO^ h t Three heats (70-835 6laquo-648 and 64gt-344) in the 2 to 3 at ^
region which are high in niobiuro and low in titanium are known to age upon creep testing at 650degC at d exhibit creep rates around 1 X 10Jhr One heat (425) with the reverse combination low in niobium and
4 H y McCoy MSK Program Senu4m1L ftogr Rep Feb 29 1972 ORNL-4782 pp 167-69
30
25
7s- i sm
20
z
z o u
15
10
05
NO y
bull704-C -
650 C
02 04 06 Al CUfTENT ()
08 10
F|laquo 624 PlUMJWa bullOMIMJM MSWatl Sttbfc fan bullraquo-staMr alaquoovs of N i - I raquo M o - 7 Cr bull Al and Ti with remcct to p i M prime precipicslioa m S0 and 704degC Alloys above the lines win form ttamma prime and those below wifl not (see Table 64 for the compositions o f the various alloys I
Tab 67 Stress-njptare data for several Urals of litaMM-almiNMM modified Hastetoy N at 704 C and 3SJO X 10 psi
Ileal Compoutiofi twt bull 1
Ti Al
Rupture life (hr)
Total strain
Age hardens at 704C
474-901 474-5 J J 427 428 429 430 431 432
18 217 24 247 24 25 25 235
raquollraquo 1148 IMS 016 035 034 074 069
006 005 0014 0064 0017 0073 0016 0057
1932 I96 0 820
2018 2006 2124
29383 36115
394 420 234 610 227 558
68 137
No No No No No No Yes Ves
Base Ni I Z Mo in Cr
Result ltgtf hardness measurement taken on ated unsirnsrd specimens
78
7S-1JTraquo 20
raquobull
14
an c
i lt
laquo0
bull433
bull 435 U^TA j raquo44l
438 _Llaquolaquo
420
- bull 4 2 5 -
bull 434
mdash~3poundt^~ 4lt8
25 30 42t -bullmdash 35 40 45
at (NbraquoTraquoi) 5 0
Fij 6 J5 Chante M kmimm ol 1 vanon beats of Nb-Ti-AI-amdiTied Haste N after 1000 kr at 650C (see TaMe 64 lor the coMposinons of the bullMiow alori)
TaMe 64 Coayison of hardness changes4 aad creep beharioi of Hasteloy N moOfttd with Nb Ti sad AI
high in titanium does not seem to show much aging Alloys containing 3 to 5 at (Nb bull Ti bull Airaquoage appreshyciably with creep rates of about I X IO3hr or less
The above results indicate that zlloys containing approximately 25 at or less (Nb bull Ti + All will be satisfactory from the aging standpoint Such an alloy would be represented by the composition on a weight percent basis of 05 Nb-I5 Ti-01 AI Alloys having concentrations of Nb + Ti + AI above the 25 at range will be more susceptible to aging
Future work will include evaluation of mkrostructure for a number of these specimens to confirm present conclusions evaluation of additional alloys to test the indicated boundaries for stable compositions and an extension of data analysis to determine whether a quanshytitative relationship can be derived that separates the relative effects of the individual elements Nh Ti and AI on the stability of alloys of this type
65 MECHANICAL OPERTIES OF TOANIUM-MODIFIED HASTELLOY N ALLOYS
IN THE UNIRRADIATED CONDITION
T K Roche J C Feltner B McNabb
Several tests were completed or are in progress to determine the mechanical properties of recently reshyceived heats of 2 Ti modified Hastdloy N in the unirshyradiated condition These alloys include two production heats (74-901 and 75-421) and six semiproduction heats (74-533 74-534 74-535 74-539 74-557 and 74-558)
behavior of several heat
Composition Hardness Kg Minimum creep rate
Cilhx) Heat wl 1 at Annealed 1000 hi
al 650C Change Minimum creep rate
Cilhx) Nb Ti AI C Nb fi + AI
Annealed 1000 hi al 650C Change
237 103 004 lt005 084 15 x 10bull 63 25 lt00I 013 166 il X 10 181 185 050 lt001 0045 186 31 x 10 bull 69448 195 092 005 0043 255 70 x 10 69-344 17 077 024 010 263 26 X 10deg 70-835 26 071 010 0053 282 60 X 10 425 048 19 008 0037 290 801 841 40 78 x 10 421 104 19 007 0O48 324 873 865 -0 8 13 X 10 424 134 18 01 0063 338 886 902 16 71 x 10 418 192 20 005 0058 391 891 904 13 22 x 10 420 190 18 015 0055 387 887 1015 128 1 X 10- 433 189 22 033 0024 475 84 1043 195 2 x 10 434 186 22 032 0061 470 933 1070 137 3 x I 0 -
Alloys aged for 1000 ht at 650degC and hardness measured in unstressed condition Creep tested at 650deg C and 470 x 10 psi f Base Ni 12 Mo 7Cr rflhratll77C
79
6 OANL-OTN 75-Wtf
5 5 k 433 1 raquo434 | 1 1 iHll
- (
I
gt420 M 1
1 tlltk^
- (
I i i
70 -835 lt i T ^ 1 | U 1 bull 69-648 6 - 4 4
I
1 425
2
1
I II 1 i i |
bull S3
M81 2
1
1 1 1 1 i
1 |
bull 237
I 1
10 i - raquo tor4 2 5 laquo r 3 2 s MINIMUM CREEP RATE 1nr)
10 io-
F 626 MiMam cteep rale of vwkms heals of Nb-Ti-AI-nodified Hastelloy N tested at 650degC aatf 47Jgt x 10 pa (s Table 64 for the aloy coiapositicm)
Four of the six semiproduction heats contain small additions of rare earths lanthanum cerium and miscii metal The compositions of these alloys were chosen to study the effectiveness of rare-earth additions for minishymizing the extent of shallow intergranular cracking Each of the six semiproduction alloys was the prodxct of a 120-lb double-melted (vacuum induction plus elec-troslag remeit) heat produced by an outside vendor The chemical analysis of the alloys was reported preshyviously5 The mechanical-property studies include the determination of room- and elevated-temperature tensile properties and creep-rupture properties in air at 650 704 an J 760degC These data serve as a reference for comparison with the properties of standard and other modified Hastelloy N alloys both in the unirradiated and irradiated conditions
The principal effort during this report period was directed toward completing the creep-rupture data on the above heats Tests are being run at three stress levels for each of the three test temperatures Most of the tests were completed with the major exception being heat 75-42 he 8000-lb production heat for which specimens are being prepared Specimens of the other
5 T K Roche 8 McNabb and I C Kcliner MW flj-gnm Stnimnu Progr Rrp Feb 2 1975 ORNL-5047 pp 61 and 65
heats were obtained from swaged rod and were annealed for I hi at 1177degC prior to test
Figures 627 through 629 are plots of rupture time as a function of stress at 650 704 and 760degC respecshytively for the 2 Ti modified Hastelloy N heats and are compared with plots for a previous heat ^471-114) of the same alloy and standard Hastelloy N Minimum creep rates measured from these tests a the three temshyperatures are shown in Fig 630 as a unction of stress As concluded previously the more recent heats of 29t Ti modified Hastelloy N are essentially equivalent in strength to the earlier heat and there is no significant effect resulting from the addition of rare earths to the 2 Ti -modified alloy As determined from past work and confirmed by the recent tests the modified alloy exhibits longer rupture lives than standard Hastelloy N at the three temperatures
Additionally the first of eight creep machines capable of tests in molten fluoride fuel salt was put into operashytion A specimen of heat 474-533 has been in test at 650UC and 300 X 10 3 psi for slightly over 1300 hr Data are not available as yet on this same heat in air but a comparison is made in Table 69 with an air test of an earlier heat (471-114) of the same nominal comshyposition
The data appear to be falling within a normal scatter band for alloys with the same nominal composition that
80
10 2 5 KT RUPTURE TIME (Dr)
Flaquo 6-27 Sueswuptare properties of several heats of 2 Ti-modified Hastcfloy N and standard HasteRoy N at 650 C I Ranges of rupture strain indicated in parentheses)
60
90
= 40
laquogt 30
20
10
0MH-DWC 79-laquoS7raquo0
[ mdashr-1 i j
- laquo gtlaquo 2 Ti-MODIFI bull0 bull AS El -LOT N (HEAT 4 r i - iu raquo i h t
B ( 39
h 4 -
r
II 6261 r ( 3 7
bullIs
I 2-476) -
laquobullraquo bull (
i
bull 174- 33
1
39
h 4 -
r
II 6261 r ( 3 7
bullIs
I 2-476) -
laquobullraquo bull (
368-47
1 6
A 474-535 laquo 474-539 o 474-557
-STANOARS HA STE
I-
LL OY N
o lt raquo74-laquo
1 L
KM
1 1 TES II
T TEMPER
III ITUR
STE
I- 70 4C
11 V 2 10 tOJ 10 RUPTURE TlaquoE (hr)
Fit 62 Strcavmpfare prupeniei of several heats of 2 Ti-modrTwd HacMfojr N aad staadaid HaateBoy N at 704r (Ranees of rupture strains indicated in parentheses)
81
Tvaoraquo 35
30
25
I- -
11 1 1 1 M IMP i | TT bull1 X I i h i j i i
bull -MODIFIED HASTEU0Y N CHEAT 471-14 -1 i IIIH |
i bull i i i
i gt lt
I i h i j i i bull -MODIFIED HASTEU0Y N CHEAT 471-14 -
1 i IIIH | j
j
j | i i
M 1 nH t t Y-
r 1 i n 1
t bull 1 I t I i |
i i i i i V bull i i bull i bull
raquo 474-533 gt 474-534 i 1 M h i t raquo 474-533 gt 474-534 I r bullv M I f f bull 474-535 raquo 474-539 I M i i i 11
o 474-901
1 Mi l l i i T
1
TEST TEMPERATURE
ill I i BOT
i IN to bull 0 2 2 5 SO5
RUPTURE TIME ffcr) bull0
F i j 6 2 9 Strcss-raptate properties of scleral heats of 2 Ti-modified Hasttstoy N and standard lUiMMoj N si 760C- (Ranee of rupture strains indicated in parentheses)
omn-oac n-tsret TV
f 2 5 raquo - MINIMUM CREEP RATE (hr)
Fig 630 Creep properties of scmsl heats of 2 ft-modified HasteHoy N at 650 704 and 760 C Solid lines arc for heat 71-114 and the dashed lines indicate bands which contain the data for the other modified alloys
S2
T M H -Ac mdash l i i r a s w a raquo laquo 1 l
larl 474-533 471-114 iflaufijc farii ltagt
500 13 24 1000 44 1300 35 55
Tlaquowraquo ion ai 650 C n d 300 x 10 pa
are tested under similar conditions and there is no indication that ronoaon by the molten fluoride fuel salt represents a sgmficani factor
jraquo rOSTIRRADUTIONCREEf MtOftRTIES OF MODIFIED HASTELLOY N
HE McCoy TJC Roche
puurade of the ORR Each experiment contains 102 miniature creep specimens in an instrumented facility in whkh temperatures can be measured and controlled by supplying heat from auxiiary heaters Only 12 in-ceU creep uwrtnim are available for postirradianoa creep testing hence the testing proceeds rather slowly The most recent tests have concentrated on lt I ) the propshyerties of six 125-lb senuproduction nests that contain 2 Ti and low concentrations of rare earths and (2gt the properties of several alloys containing both niobium and titanium
The results of tests completed to date on the six heats that contain titanium and rare-earth additions and the (OjOfXKb commercial heat that contains titanium are summarized in Table 610 Previous tests at temperashytures of 6S0 and 704degf showed that the creep propshyerties of these heats are about equivalent The rupture nfe at 650degC and 40JO X I 0 3 psi varied from 1200 to iSCC hr and the rupture life at 704degC and 350 X 10 psi varied from 170 to 200 hr Final conclusions con-
Postirodtion creep tests are in progress on specishymens from five experiments that were irradiated in the
6 T K gnmSemm
Roche i ( l-dlner and B McXabb MSK Pro-mm flop Rep Feb 2 1175 ORNL-5047 p 7
a t 6 S r C a r laquo s a o M n i atUttMecatca
ABojr Ten mantel
Irradiation tcmpcniafle Si ecu
(10 pa) creep rate
(hr)
Rapawe life (hrgt
Total fracture straia Cufaycailioa (gt
474533 R-I9I2 R-190
R-I929
650 650 7ltK 760
400 470 400 350
0025 0050
0035
2311 I I I 5 2
2022
72 217 Ti 04 At 7 6 4 7 J
474-534 R-1913 R-1909
R-1930
650 650 704 760
400 470 400 350
0021 007
0008
5722 660 5raquo 7 3
16 2 209 Ti 0 J 3 Al 001 3 La 69 35 28
474-535 R-I9IS R-I9I I R-1922 R-1926
650 650 704 771
400 470 400 350
0016 0099 0023 0019
7 6 M 930
4677 6454
1V6 2 1 3 Ti 055 Al 004 rare car TS
123 139
474-539 R-I9I4 R-I9I0 R-I92I R-1925
650 laquoS0 713 774
40 JO 470 400 350
0020 011 0C3I 0000
601 739
4295 12200
108 193 Ti 020 Al 003 Ce 97
165 114
474-557 R-1920 R-1923 R-1927
671 713 771
470 400 350
0045 0044 0019
2174 162 434S
1 0 214 Ti 002 Al 95 S3
474-55 R-I9I6 R-1924 R-192
650 716 795
470 400 350
0X192 0021 0012
1793 475
79 205 Ti 0-02 Al 002 U 6 II
474-901 R-1936 R-1937 R-1907
650 70laquo 732
470 470 470
0069 015 014
1716 332 525
1 3 10Ti00Al 52 1A
AD specimens lancaM I hr agt 1177C prior (o irradiation for M 100 hr to a thermal thence of vlt3 x 1 0 neutronscm Alloy nominal bast composition of Ni 12 Mo 7 Cr -005 C
S3
cerning the postinadiation properties (Tabk 610) are not possible because the tot matrix ha not been comshypleted Specimens irradiated at 650degC and tested at 650degC hare rupture lives that are about half those of the unirradiated specimens but there are no differences in the properties of the various heats that are considered significant in view of the limited data The properties of afl heats are considered good after irradiation at 650C After irradiation at 704degC and testing at 650degC and 400 X 10 pa the rupture lives of heats 474-533 and 474-534 appear to be lower than those for the other heats by a factor of 3 In afl cases the rupture life and the fracture strain were lower after irradiation at 704degC than at 650degC After irradiation at V760C and testing at 350 X I 0 3 psi at 650C the rupture fafe varied from 43 to 1220 hr and the fracture strain from II to 114
respectively Thus differences in creep behavior of th-se aftoys likely become progressively more important as the irradiation temperature is increased
The fracture strains of the various heats appear to show significant trends with increasing irradiation temshyperature Heats 474-533 and 474-557 have good fracshyture strains (6 to 104) which do not decrease apprecishyably with increasing irradiation temperature The fracshyture strains of heats 474-535 and 474-539 are i t the range of 10 to 16 and do not change appreciably with irradiation temperature Alloys 474-534 and 474-558 show decreasing fracture strains with increasing irradiashytion temperature The behavior of alloy 474401 appears to be unique in that it shows a marked drop in fracture strain as the irradiation temperature is inshycreased from 650 to 704C However this effect may
Ta t 611 bullMtffiall rNamwsaKsrc
Alloy Test HftlhCT
Sims HO psi)
creep rale
Rapt me ate lthrgt
Total fraclarc sin in
rfhraquogt
Rapt me ate lthrgt ltgt
428 R-1948 470 0043 2221 119 474-533 R-1908 470 0050 I I I S 78
R- I9I2 400 0025 2311 72 430 R-1947 470 lt00049 9720 4 8 r
432 R-1946 470 lt00005l 9720 0SC
431 It-1945 470 bullCO0024 972f 424 R- I9 I9 350 Mraquo 3160
400 000024 1406 470 000033 4526 550 00066 9494 78
424 R-1944 630 00096 3554 104 420 R-I9I8 350 bullM) 5322
400 -v-0 1405 470 000021 4509 550 000037 6959 630 000080 3343 700 00062 2776 4 3
420 R-1943 630 lt000l7 10680 18 418 R 1917 350 000002 6514
400 000007 1406 470 000014 4523 550 00040 7948 54
41ft R-1942 630 00022 5592 72 434 630 lt0085 129 II 433 R-1949 630 lt0 00 l l 6600 075
AN specimens annealed I hr al I I77degr prior to irradiation Irradiation carried out al 650C for approximately 1100 hr to a thermal flaencc of Vraquo x 1 0 neutronscm See Table 64 for detailed chemical analyses Test still in progress Stress increased on the same specimen in the increments shown
S4
tt12 laquo T SIMMS CM
AcebaMk maibS0CbjMlaquotoi rtniliij1i4
CoMBoanmi iwt rt Co H o
lOOObraMeal
ctccp cveep behavior
bull S O T f o r V I I W b f 4
CoMBoanmi iwt rt Co mdashjn bullnn a m t H o
lOOObraMeal
ctccp cveep behavior
bull S O T f o r V I I W b f 4
Nb T i Al Nb bull Ti bull Al
428 No No No 247 Olfc 357 474-533 No No No 217 laquo4t 3 raquo 2 430 Yes Yes Yes 2J 0 J 4 492 432 Yes Yes Yes 235 0Alaquoraquo 4 A 3 431 Yes Yes Yes 25 074 4 9 424 No Yes Yes I J 4 I S 010 33 420 Yes Yes Yes 10 I S 015 3S7 4 I t No Yes Yes l laquo 20 005 3 1 434 Yes Yes Yes iaraquo 22 032 470 433 Yes Yes Yes l laquo 22 033 475
Sec Tabfc 1 4 for c l e t M e U t f e M U analyses
F I O M Table 4 rFroaraquo Table t A based ltM ctmatemiomt of data i ON novate Me aMl total u n a rfFrow Table 611
be related to the strain rate a summary these sparse data sanest that the fracture strains of alloys cow-taming only titanium and those containing titanium plus cerium remain at adequate levels as the irradiation temperature n increased while the fracture strains of the two alloys (474-534 and 474-558) that contain lanshythanum do not Additional specimens were irradiated and tested to check tins important poatt
Section 64 of this report deals in detail with the metaOurgical stability of alloys containing Nb Ti and Al in the unirradiated condition Some of these alloys have been irradiated and limited test results are availshyable (Table 6) The alloys were annealed for I hr at 11770 prior to irradiation for about 1100 hr at 650C The anneal at 1177degC should have dissolved most of the alloying dements and the subsequent period at 650degC may have resulted in the formation of gamma prime Precipitation of this embrittling phase abo strengthens an aBoy hence the postirradution creep tests should show whether significant quantities of gamma prime were formed As dacussed in Sect 6 4 precipitation of bullhis phase may be strain induced and a detailed analysis of the creep data wSI be required to determine whether the gamma prime formed m the specimens during irradishyation or whether it fonrvf as the spedmens were stressed initially
The data from Table 611 and information from Sect 64 are summarized in Table 612 which shows that the
conclusions are reached with regard to aging of creep specimen in the unirradiated and irradiated con-drtions However hardness measurements on unstressed umrradaied specimens fail to be a good indication of agt in aRoys containing nioHum Alloys having a com-tlaquoKd titanium and aluminum content as high as 357 at had excearnt postirradution properties ABuys with higher uimbimd concentrations are quite strong Kut no conclusion can be made about their fracture stains All of the alloys containing Nb Ti and Al are quite strong and can lake considerable strain before fracturing ABoy 434 has a low fracture strain waste no conclusion can be drawn relative to ahoy 433
The alloys containing Nb Tiand Al which have been evaluated thus far are likely too highly alloyed even though some of the fracture strains jre acceptable Less highly alloyed materials are being irradiated
67 MlCKOSTRUCTURAL ANALYSIS OF T i T A N M M I O W I E D HASTELLOY N
D N Braski J M LeMnaUr G A Potter
The first part of this section presents the results of microstruclural studies of two titanium-modified Hastefloy N aloys 472-503 (designated 503) and 471 -114 (designated as 114) Previous analyses of these tame two alloys dealt with their nricrostructwss after
bulls
afmf aad after postsrraanrtion creep tests In the pressai m f j i l f the nacroairaciaret ot hutfcaftoys were analyzed M an attempt 10 explain some w u l pouarsdanoa creep teattts M sptoaaas that were pven a ltjfgtrtj higher soratiua aaaeahnf treatment Move trratmttian I V mdym showed that many at the wlaquo ipninsrai owe t f i e mhumimracnni and that tkc poor creep properties ttiaMmsonsr cases tie related lo the iahomimnKitsti D M ftnamg prompted a sindy aanei at iiiiidwiag asm hinaimiatimi llamllin N aloys The problem if betw approached by rcdactae it carbon coateat of the anoy aad by gnaw carefal attention ID the tahjicatani pmmHcn The resales ot taaml narranrnti to tnWicalt hiaanpariita alloys arc pKsvnacd m BM secoad part o( thjis section
471 M f u m i r i a i J M r laquo f JkaaysSISamllH
rVanmnaaaaa O H I I o n The retails of creep ten o specimen of ahoys 503 aad 114 which had keen PKVSUmdash)y irradiated in the ORR al 7a0C Me given in I hgt 6 J I The creep tots wete contacted at 6501 n a turn and of 350 X I 0 3 pa This partwalar scots laquoraquof spnameas was designed lo show mc effect of tobmoa anatjbni remperatarc on the postkravniion aeep rop-r-re We of the naieriah The solation anneal was a I-hi heal ireainieM and was given lo all sprcimens before ikes were irradiated 4 men in Fig 6 J I ibe 503 speci-men given the standard I br at 117 ( solation anneal demonstrated food creep iiipiwic We wbifc the 114 tprvmen given the amc ircaimenl had a comparably short lifetime However with an mcrease of only ^30degC in aim latins temperature ahoy 503 had a freatty reduced lifetime wMe ahoy 114 thawed marked improvement It wn corasdered ankkety that tkese rendu coaM he canted by changes in solution anncaing tcmpcrainre alone and other posabh cxpla-aatioas were soajbl It b important to note that despite the apparent mtfaMiiy in creep behavior the properties of the 2 Ti modified alloys arc gencraiy food The problem is that lo determine why tome specimens have poor properties A bullohtlhm to this problem was sonjht by carrTafly anatyimf the microttrnctnres of the two alloy 503 and 114 tpecrmens described above
7 D N bullgt I M UMmfccr jml f i A Puller JfSff AOBVM Semtmmm ffngr Hep Am J I 174 OHm-5011 pp 2 M
n I) S Hrai I M Inraoker j J ti A fnwr 10ft rtomm Semtmmu hop Htp Frh 197 ORNI -5047 Pf i vn
am-a t-laquotlt H 0 O ^
snvss ifwfi bull raquooooraquot
llaquo00 i bull ~ i
bullooraquo 7 1
SOI I
1 z- 2 aosf tr
w r T~iHr-wV---
eoo^mdash mdash mdash - 7 - l V mdash ^
laquoooo tlaquooo laquotoo laquoJOC tOkwtio mntauvs rtanjntTtM ltKgt
Hattys SWanf IM at wfTC ahw Irmthmm toOU wr laanm
TtasmnJtvJmi eltclnm nncrattwny Samples were preshypared for iransnaanoa ekciron nacroscopv iT lMi bgt elevtropohaaaf small transverse sections a( the tested creep specimens in perchloric acid sohrtions Frfures tgt32 and 6J3 show electron naaofrapbs repteseniattvc laquogtf 503 and 114 specimens respectively Hfare tgt32 shows an area near a frain boandargt in the 503 specishymen annealed at I I 7 7 C The nacroHnictaie was obshyserved to contain NT-type jwkaiii both in the ftsin bnandiry aad m the form of tmaH ptattieis DMoca-lions were nearly always foond to be aawoMcd raquotih ike MC plasestis The 50specimen anaeaWd at iagtraquoC had ssaabw featarn laquoFsg 6-321 In both speenneas ibe MC pbielets were coaccntrated near the grain boundshyaries This tajfrsts that the element or elements (probshyably titanhan) awimf ap the MC-type carbide in both specimens wete not anifonaty dittrrbwted ihroafhoat the ntntrix Rfare 6JJ shows ehxtron araquoao|raphs of ike 114 specimens aaaeated at II77C(Fig6J3tand I204f (Fhgt 6J3raquo These specinwas also contained tine hJCMype cjrbidei bat aalwd of formmf pbtekts they precipitated oat on stscUnf faalu The suckmf fault precipitates initiate from iaiocstioat aanriaUd with preexitlmi or primary MC carbides and frow atom ( l l l l pbmrs The primary bX carbides (the dark
9 J si raquotVudt j4 raquo ) IWHUM PariHl Praquogt^i-raquolaquo
FfctJL iirrcraquogt
IMi to to ON m C alaquo r c w i laf I fct laf ItonlSMT
FfcUX 11 rrr laquoraquoMMMI~
bullraquo laquobull IH aft i 4rflt ifctMijarr
bull7
bullJS maunutj I t 93 n r r r IFBJ 6jlaquoaraquo a hai laquobull
face ocal oadu laquo laquowieau of
I M laquo F v J 4 laquo ^
f i W t laquomajm awir loaae Iraquoraquo bull ulaquoaagt aavm tar rmttte mctmm of tar Maaak TW laquoaraquo-hlaquoir i i i i f m mt omtfutd raquoH w w n n MC-fraquoar pat-iarraquo atad ar m bar pml r i nraquo the | bullveil) at fafencaiMa)- Suit aifcaiettfaiamare i loth atatuicw M Fa 6J6 bgt the iafJMf t laquo mdashlaquopmm ukra gt4 oW 503 aajdaara 1W 503 laquofrltMMraquo J M K J M j i I5M C hai oaka iem tracks Ifiy 634raquo| feat laquoa a lacat arja aaaarealh Me to
ka4 a sfcvrt crer raatare life aha M a ^bullXM2laquo4hKk m l Mi fit my (filaquo J5 IL K M -
bullera m mm Sm mtomm (Fftj J4raquo|i h mm akv I thai aartee aacks bull jraiar fiw layer TW 114
I2MdegClaquoFlaquoJ$raquo)lt
the tenet 509 aaaatn (Fig 3Saraquo Hat layer tana) a e 53 mm 114 air-aafi
aa ie i t jn at II77C ai anjon
baen of i l aaa ltA0J raquo ) a w u t e m I at aacoad 617 after OlaquoCP tern at I W f C raquooraquo i r at bullraquo M a a OI I I I i n 500 pmm oBjaea- T V bet of cartwtci ai tar tarface lever any teae at tarn
in I U a laquoN1 i fcc ~ IW f f v i olt bull m bullbullbull ngt bull mp ttaatmdash ftuauwt l laquo a i i rlaquoWKftll~l raquofJaar 1731
617 M
+rnm
OTraquomm
ttm mOtOimTttrc am IMtMTC
growth m the 503 specimen (Fig 6 35| during the soMMwa mmtd h is Midear as to
certain tptcimrai haw the carbide-free layers 1 specimens were svoposedry fabricated in the
same way The malts of the mrtafcajraphtc and TBI lt
lion cannot be nsed to fnty explain the i which led to the early creep fnlnrc of two of the specishymens studied However we banc shown that a awnber of aticrostractaral inhoniofmirties exist in the 25t Ti asotified rLarloy N aftoys induding carbide-foe sur-face layer tnrft-grsia lint snrface hyers nmeratwd carbide strinnprs and nononifonn diHribniions of Mf-type carbide nor grain boundaries Some of these
ties appeared to affect the resnhs of tots and may also inflnence other hnpor-
snch as those renting to tclarium attack Consequently a stndy was initialed to prodace rtsstd-loy N aftoys with more homogenous nacrostradares
bull J J llinnnmiim UnmfJy H Aiayraquo
The problem of prodacing Hastdoy N alloys with hiuaugtmuui nacrostructures is being approached in two ways The first is to reduce the carbon content in the atoy to ensure that aR of the MC-type carbides are diaailvud daring the solution annealing treatment If all
the carbides could be held in solution daring fabricashytion the formation of carbide a ringers might be eKna-aated The second approach b a detailed evaluation of tbt fabrication process This latter effort is prwmily
at identifying the steps at which the different ae introduced and finding suitable
akemate processing methods to remove the anno-anajftiti A definite concern throughout the entire study is that any successful fabrication changes also be
immmiil practices The first series of experiments was
to cmnJnate carbide stringers by reducing the carbon content of the ahoy Thermodynamic takula-tions aung data from previous experiments indicated that aN of the carbides should dnsorve at I I77degC in aloys with carbon contents of less than OA45 wt 7 Therefore two aloys 451 and 453 both wtth a nomishynal lauteaoy N convocation (13 wt Mo 7 gtt Ct bal Ni) and 144 wl Ti were cast into l-m-omm marts having carbon contents of 0017 and 0035 wt 7 respectively The fabrication schedule called for the cast ingots to be hot swaged at I I77degC from a I-in to a 0430-in diameter and then to be annealed at I I77degC for I hr The rods were farther reduced o a 0 J37-in diameter by cold swaging annealed at I I77degC for I hr and cold swaged to raquo final diameter of 0250 in One-inch-long samples were then cut from each alloy rod
bull 9
encapsulated in quart urJer an argon atmosphere and aged at 7G0degC for 16-5 hr to precipitate the carbides After aging the carbides in alloy 453 (0035 C| were extracted clectrochermcally in a methanol 107 HC1 solution Consecutive extractions produced the profile shown in Fig 6 J 7 of wt 7 carbide precrpiuie through the thickness of the sample The profile for alloy 453 is considerably more uniform than those obserad for alloys 503 and 114 specimens aged at 750degC for 1000 hr The difference may not be entirely due to a reducshytion in carbon content because the 503 and 114specishymens were swaged from bars cut from i-in-thick plate not from drop-cast ingots (Carbides are fairly unishyformly distributed in the grain boundaries of the 2-lb laboratory ingots while they appear as stringers in the A-in plate) Meiallographic examination of the aged 451 and 453 samples (Fig 6 J 8 ) showed that the reducshy
tion in carbon content did not ehrninafe the carbide stringers However the stringers were liner and more evenly distributed than those observed previously (Fig 6J4o) Carbide-free surface layers were observed in both specimens a typical surface layer in a heavily etched 453 sample is shown in Fig 6 J 9 The depth of the carbide-free surface layer was V0U03 m
Fatifcpnwn One of the moat critical steps in fabrishycating tbtf^iioy N aRoys with respect to its effect on microstruciurr laquo the solution anneal Electrochemical extractions on an as-swaged alloy 453 (00353 Cgtsamshyple showed that a moderate number of carbide panicles (M) 2T) was present Hi the microstructure after procshyessing It a suspected that the sample was not adeshyquately annealed at 1177degC prior to the final cold swagshying operation That is the annealing lime was too short or the annealing temperature was actually less than
90
0080 O0TS FMQHOWTEtOF
X amy Mkif S03 JI 1177 f M lt jpee gti laquocopylt for
I ITTC Therefore the respuMe of tiUmum-mudifWd thneloy to sohnion aaandias at I I77degt ws stmfced as a fmctioa of time at temperature
Samples of aloy 451 |OJOI7 Craquo W anon at I IT7degC for 15 mm lo hr The cleaned etectrucheaacaRy for 6 hr to remove any nr-faoe effects ami the carbides were electrochemical extracted separated ami weighed The resatts of this experanent aw plotted m Rg 640 (My extremely
bullis of prcopitaies were present a samples for 2 hi or more At times less than 2 hr there
scalier m the data hat m geaerai chfHIv preopifc te was extracted These remits indicate
that JO to 60 mm are weeded m addition to the stanshydard 14 sohtiox anneal at 11 T T r to dtooKv the carshybides completely Muumaptu of tectioas from each of the samples r f aloy 451 from the first jaarmaj series are mown irgt Fig 641 Little gram growth was omened between the 154am and 14v anneals while mgbt grain growth was etideai after 2 hr at II77degC As expected rather extensive growth occurred at the longer j times of 4 and 8 hr
FfcnJB Wcwsmnmwof limn wimfml llsmliy N amyi451 jM7Cgt anl 4raquo IftWW O after coal maawwanl aanf at TMTCfbr I US fcr (laquogt Alloy 451 laquoAgt AHny 45 J
91
foert seed-
Abhoaeb most of ike effort m ties stedy hat beea pit wii be exammed mdashtuiognfkicjh before deeded towvd etmeeetioa of canede miegrn a the aflaquoer a soaatioa aaeri at 1177C I b j bull a bullloys enprrimdashrii aieafao mdashdet way to i i i f i i a n the iimiag eomt a t e mdash taebidr few b y m cjHeoftie carbide-free layersm oar experiment Bee- alnae ibr mdenrd irrliw nf
a w that n any effects of bet or cob) Y-133201 mmraquobemremoeedby
there is ike coaaderata eery bull fact be the bey to uioootaH a ahoy A aoajher of rchmvesy eeeor cheaats bull the way ibe eeecviel is leeeeed amy mwe oaaaaptK effects oa
4SI awi 453 aie ui l i l l aai wal be tnMcated to CiVideraquofiw]|Bmemmmmmmmmmmmmmml 025ampmemai rod with special attewtioa peel to the
CSl nOwal t h e W O f k HBOC l lHOWHKNVt the B I O O 0 B H K SO
J SALT COMtOOON STOKES
J R J R Difdkno E J Lawrence
by of
FbgtraquoJ9 i t u n a
453
The conoaoa of bow) asefcei-mniten ihtonac salts has ben the research for aemy years Resell seen as FeFj NiF and HF in the sah react with con-sliteeats of the alloys bet corrosion from these soartes a basiled by the seppiy of reactaets The strongest oxidant of the normal coaetiteeats of foH salt is UF 4 and of the major coastrteeets of most iron- am nkfcei-base alloys cbrommm forms the most stable fleoride Coaeeoeeetly the major corroajon reaction between
02 OftftJL-OWG 7 5 - 1 2 2 4 )
5
imdashimdashimdashr o 1st ANNEALING RUN laquobull 2nd ANNEALING RUN o 3rd ANNEALING RUN bull 4th ANNEALING RUN
2 3 4 5 TIME AT 1177 C (hr)
FfeSvMl AmcmMoliBAim$9tncmihomraquonor4Slmraquotmgtctomlt4Vmmmitioraquo
8
bullfii7rc
92
to) CM ltlaquogt
FltMI MkioaMjai of mdash bull I br kit 2 br laquoraquobullraquo 4 br jfld if) nr
i laquorf raquo r 451 aftw M M M Mlirrcfcw tol IS i ltraquogtMl ltrgt
nickel- or iron-base alloys and molten-salt reactor fuel salt has been found to be
2UF 4(dgtCrfc)^2UF(draquoCrFj(dgt
Because the equilibrium constant for this reaction has a small temperature dependence temperature gradient mass transfer can occur and results in continuous reshymoval of chromium from the hotter sections of a system and a continuous deposition of chromium in the cooler sections
The experiments described in this section are being conducted to determine the corrosion rate of various
sall-afloy systems under controBed test conditions The variables include compoatiou of the alloy oxidation potential of the salt temperature and exposure time Afl loops incorporate electrochemical probes to measure the concent ration of uranium and transilion-metal flushyorides The systems used to conduct these experiments include one forced circulation loop operated by personshynel in the Reactor Division and three thermal convecshytion loops Five additional thermal convection loops have been constructed and are being prepared foi effrj-tion The status of these eight thermal convection loops is summarized in Table 613
93
i l l l f lS
IA
raquo
raquo
tit
MRSkr
l l t e M JS
rN
it
h i
M l
laquo J I Fael M l
Two thermal convection loop NCL 2 IA and NCL 23 have been operating with M S W fuel salt iLiF-BeFj -T lr f^- lF M M 1 7 - O J mote ^raquo lo obtain baseline common data NCL 21A is a HasieOoy N loop with specimen of the same material At with a l thet-mal convection loops dghi specimens are inserted in the hot and the coid legs The 16 spedmens are reshymoved periodicaly for visual examination and weighing The results of the weight change measurements are shown in Fig 642 The corrosion rate of the hottest specimen in this loop is somewhat higher than has been observed in other rfasteUoy N systems (see Sect 682 discussion of FCL-2bgt The higher corrosion rale of loop 21A relaies to the relatively high oxidation potenshytial o( the salt in this loop ( U M about 10 I Horn-evei assuming uniform removal of material the corshyrosion rate of the hottest specimen was 024 milyear which is within acceptable limiis This loop will conshytinue to be used lo obtain corrosion data for Hastelloy N in kali with a relatively high oxidation potential
Loop NCL 23 is constructed of fnconet 601 and has specimens of the same material A loop was built of tnconel 601 because of this afieys resistance to grain boundary penetration by lefuriwn Since the alloy conshytains ZV Cr there was concern about its ability to resist attack by molten fluoride salt The corrosion rate of Inconel 601 in fuel salt was determined from weight measurements of the 16 spedmens of loop 23 and the results are shown m Fig 6 4 3 All specimens lost weight and the lost shown by the hottest spedmen w very large The material lost by the hottest spedmens did not result in uniform removal of the surface but resulted in the formation of the porous surface strucshyture shown in Fig 644 As shown in Fig 645 electron microprobe examination of this spedmen showed high thorium concentration in the pores The only known source of thorium was the salt which contained T h F 4 so it is very likely that the salt penetrated the pores Continuous line scans with the microprobe indicated a depletion of chromium near the surface Figure 646 shows the results of analysis for Ni Cr jnd Th This figure clearly shows the chromium concentration gra-
94
OMK-WH TO-IZZ4 1 1 1
0 laquo000 2000 JJ00 4O00 5000 SPECIMEN EXPOSURE TINE ltgt
Flaquo 642 Welaquoht campMfts of HasteBoy N p-ciaraquoeas fro loop NCL-2IA exposed raquo MSMt fad o k at the indicated tenMcnaMe
0OM-0VC T raquo - t laquo laquo 5
SPECIMEN EXPOSURE TIME (Hrl
F 643 Weht changes of Inconei 601 specimens from loop NCL-23 exposed to MSBR fad salt at the indicated tem-peratare
dient and provides further evidence of the presence of thorium in the pores Deposits such as those shown in Fig 647 formed on the specimens in the cold leg and the deposits were identified by microprobe analysis as chromium This compatibility test of Inconei 601 in MSBR fuel salt shows a relatively high corrosion rate and it is doubtful that this alloy would be suitable for use in an MSBR under the conditions of this test
The lower limit for the U ^ U ^ ratio in an MSBR will likely be determined by the conditions under which the reaction
4 U F + 2 C i r 3 U F 4 U C 2
proceeds to the right Because the salt in loop NCL 23 is strongly reducing with a U ^ U ratio of less than 6 it was decided to try to reproduce the results of Toth and
Gilpatrick1 wiuch predicted that at temperatures below 550degC and VV ratios below 6 the U t would be stable However graphite specimens exposed to the salt for 500 hr did not show any evidence of U C 2 The specimens used were made of pyrolytic graphshyite and it is likely that the high density of the material limited contact of the salt and graphite The experiment is being repeated with a less dense graphite
682 Fad Salt Forced Gmriatioa Loop
Hastelloy N forced circulation loop FCL-2b has been operated during this reporting period to gather baseline corrosion data under conditions where the i r U ratio was relatively low (see Sect 23) Eighteen itastel-loy N specimens were exposed to MSBR fuel salt with a U 7 U V ratio of aUut 100 The specimens were reshymoved at predetermined intervals for visual examination and weighing and the weight changes are shown in Fig 648 Six specimens were held at each of three temperashytures 704 635 and 566 eC Of the six specimens at each temperature three were exposed to salt having a velocity of 049 msec and three to salt having a veshylocity of 024 msec No -ffect of salt velocity on the corrosion rate was found so each data point represents the average weight loss of the six specimens The weight loss of the specimens at the highest temperature correshysponds to a uniform corrosion rate of 011 milyear Uniform corrosion at this rate is acceptable and well within the limits which can be tolerated in an MSBR
Following termination of the ^3200-hr corrosion experiment FCL-2b was to be used to make heat transshyfer measurements This operation has been delayed because a salt leak developed and a section of the W-in-diam Hastelloy N tubing had to be replaced (see Sect 23) Examination of the tubing in the vicinity of the leak is under way
Further corrosion measurements will be made in this loop with the U7U ratio at about 10 Additions of N i F 2 traquo the salt will be made to raise the U ^ U 3 ratio to the desired level
683 Coolant Salt Thermal Convection Loops
Thermal convection loop NCL 31 is constructed of type 316 stainless steel and contains LiF-BeF2 (66-34 mole ) coolant salt The 16 removable corrosion specishymens are also nude of type 316 stainless steel The maximum temperature of the loop is 639degC and the minimum temperature is 482degC The initial objective of
I I L M Toth and L O Gilpatrick The Equilibrium of Dilute UP Solutions Contained in (imphite ORNL-TM-4056 (December 1972)
95
_o o
tvri O
o O
-o d
FtJ 644 Microfracture of Incoad 601 exposed lo MSBR fad sah al 704 C for 720 hr As polished
Y-1312W
BackscoMered Electrons ThMc X-Roys
Ffc 645 Electron beam scanning image of Incond 601 exposed lo MSBR luH tall for 720 br al 7 0 4 C
HImdash3000 COUNTS FUU SCALE Ctmdash3000 COUNTS FUU SCALE THmdash000 COUNTS FUU SCALE
~~1
Y - 1 3 1 2 1 9
I L i JLJJJ - mi
Ffe 646 Mfcfopnbe ctmtimomi K M K M M M corroded ana in IMCOMI 601 exposed io MSMt M salt for 720 hr at 704deg C
97
Fij 647 Microstnctare of lacoael 601 exposed to MSraquoR fad alt at S66degC for 720 kr As pofohed
cobalt-base alloys is being evaluated in the unstressed condition in the TV A Bull Run Steam Rant Two heats of standard Hastelloy N tubing (N1S09S and N1SI01) are being evaluated in the stressed condition from 280 X 10 to 770 X IO Jpsi
The method whereby the specimens are stressed is shown in Fig 649 The wall thickness of the gage secshytion of the specimens was varied from 0D10 in (77X) X 10 psi) to 0030 in (280 X 10 1 psi) to produce the desired stress range The raquo-in-OD capillary tube conshynects the annulus between the two tubes to the conshydenser When the inner tube ruptures steam passes through the capillary and a rise in temperature of a thermocouple attached to the capillary indicates rupshyture Time to rupture can be taken directly from the multipoint recorder and plotted vs sfess for design purshyposes Data of this type for periods as long as 11000 hr were reported previously17
A photograph of the specimen holder (Fig -gt0) shows the ten instrumented stressed specimens the four uninstrumented stressed specimens in the filter basket and the unstressed sheet specimens bolted to the speci-
12 B McNabb and H E McCoy MSR Program Semiarmu Progr Rep Feb 28 1975 ORNI 5047 pp 94-101
OJKM-0W4 TS-lt22laquolaquo
O 500 IO00 ISOO 2000 2500 3000 3500 SPCCIMEN EXPOSURE TIME (hr)
Ffc 648 wetgtt changes of HMCHOY N from loop FCL-2b exposed to MSBR fact salt at die Minted temperatare
this loop is to provide baseline corrosion data on a comshymercial iron-base alloy The loop has been in operation for 248 hr
69 CORROSION OF HASTELLOY N AND OTHER ALLOYS IN STEAM
B McNabb HE McCoy
The corrosion resistance of several heats of standard and modified Hastelloy N and other iron- nickel- and
98
OB -OK M - 3
STEM SUPPLY 99ooplaquomgtr
t laquo - IT raquolaquobulllaquo
C t f U M V f TUBE
TUBE BURST SPECIMEN (TYP 10) WATER OUT
RETURN TO CONDENSATE STORAGE
f 649 ScfccaMtk of dostfe-watcd tobe-barst eciam
men holder The filter basket bolts to the small flanges on each side of the sheet specimens (shown exposed) so that the specimens are covered and the flow of steam is uirected over the specimens rather than around them The steam enters the specimen chamber near the middle of the stressed specimens in front of the unstressed specimen holder and is directed lengthwise over the two stacks of 2-in-long X H-in-wide X 0035-in-thick sheet specimens The steam passing over the specimens flows through the Neva-Clog filter to prevent scale from entershying the flow restricter orifice or the remainder of the steam system The steam is condensed and relumed to the condensate storage vessel No specimen has lost any scale so far but some of the Croloy-type alloys are beginning to develop blisters a prelude to scaling The oxide on all HasteUoy N specimens is thin and adshyherent with no evidence of scaling Some of the unshystressed Hasteiloy N specimens have been exposed to steam for 19000 hr at 538degC and 3500 psig Several alloys were included in this study andas reported preshyviously 3 they displayed a wide range of oxidation rates Several obeyed the parabolic rate law Aw = Kt0gt where Aw is the weight change in mgcm 2 r is the time in hours and AT is a constant Figure 6SI is a
log-log plot of weigh change in mgcm as a function of time in hours Note the sudden increase hi the rate of weight change with each alloy gaining approximately 05 mgcm z over the last 4000 hr This probably indishycates deposition of some substance on the specimens at a rate that was equal for all specimens We noted preshyviously that fine particles of iron oxide that was enshytrained in the steam had deposited on the specimens but this deposition occurred at a much lower and conshystant rale
The increased rale of weight gain for bulllaquo specimens was discussed with Bull Run engineers The Butt Run facility has had several instances of condenser tube leaks in the last year of operation whereas in previous years few if any condenser leaks occurred The cooling water in the condensers is at higher pressure than the condensshying steam to prevent back pressure on the turbines and when a leak occurs untreated cooling water is introshyduced into the steam system hot wed Continuous monitoring of silicon in the four hot wells (condensed
13 H K McCoy and B McNabb Common of Seven fron-md SirkelBttr AUoyj in SMptnrihctl Steam tt IWmfF ORNL-TM-4552(AupB( 19741
99
yen ttSO fhnnnif of MM M H mwooaw dumber attar I9JBM hr of ixpamdashJI Fntaro to note ire the ftrcacd D M mcmlnMnmicd iptcimem m ihr fitter Iforeiivimdl the two grown laquo f umtreued ipecanens and the tea nwuaacMcd tfrcued iptnanm The Miem-rf ltrcanem haw an oniadc domclcr at I in and a length of 3 in
steam wdfc) indicates a condenser leak when the silicon lewd increases and the leaking condenser can be isoshylated and repaired The condensed steam (and any coolshying water mtrodticed by condenser leakage) poses through demineahzrrs and is ntonitored again with silishycon and other irapuifies being held below acceptable broils before the condensate is returned to the steam system Even though care is taken to prevent excessive amounts of imonritres in the steam system the farihiy is evidently opt rating with a different level of impurities than had been experienced before condenser problems developed Some evidence of indium shkate as a Mack-Mi gray deponihas been observed on some safety-valve seats and this is poanoty the material that has deposited on the specimens The oxide on most of the specimens is Mack or gray and no changes in i u appearance were noticed during routine examination and weighing of the
specimens When the specimen holder is removed for the next scheduled examination an effort w i l be made to determine the composition and nature of the deposit
by Bofl Run engineers in the near future to ehrninate the problem of condenser leaks
Some of the aloys represented in Fig 651 lost weight inriiany before gaming at an accefcaraied rate during the last 4000 hr These alloys were Hastetoy X ttsynes alloy 188 and rnconel 718 and they contain approximately 205 Cr Other juvestigstors have reshyported weight losses due to loss of chromium in steam at high temperatures I i is probable that these aHoys would have continued to lose weight if the steam conshyditions had not changed new specimens of some of the aloys WW be inserted in the lest facility when sieam conditions improve
MS
t I t OBSERVATIONS OF REACTIONS IN METAL-TELLURIUM-SALT SYSTEMS
J Brynestad
Several criteria must be met for a good screening test system for the teflurium corrosion of Hasteloy N
1 The teflurhun activity must be appropriate reproshyducible and known
2 The tefflurium must be ddivered uniformly over the sm|jie surfaces and at a rate sufficient to prevent excessive testing times
3 Preferably the system should operate under invarishyant conditions during the test run
4 The system must be relatively cheap simple and easy to operate
in the MSBR the production of tellurium per time unit wnl quickly reach a constant value and in due time a steady state will be reached where telurium is reshymoved from the melt at a rate that equals the rate at which tellurium is produced
i to reacting with me Material of which the circuit is constructed leBunum could be reshy
moved by several means which mdmfc the foetamug
1 The | ining system Since the MSBR is to be equipped with a pm ceiling system to remove Gemm product telufium might be effectively removed from the salt by appropriate measures
2 The gas phase If the gas phase is contacted with a getter such as dumnium wool the tchwrimn activity m the men ought be kept dose to that defined by thelaquo
^Cr TTe(k)^ TeltgH ACrlts)
Thu activity is sufficiently low that Hastdoy N would not be attacked
3 A getter immersed in the salt mdt Obvious disshyadvantages of this arrangement would be the probshylems of mass transport in temperature gradients and the lack of a candidate material
Until the steady-state condition in an MSBR is more dearly defined it is impossible to state the likely tellushyrium activity It is only known that in the MSRE stanshydard IfasteOoy N was embrittled (probably by tellushyrium) In the MSRE the steady-state tellurium activity - if ever reached - probably was defined by gas phase removal and was likely rather high
Until the steady-state situation in the MSBR is deshyfined it must be assumed that one must deal with the MSRE condition under which standard Hastdloy N is embrittled In order to define this condition we have tested several systems with defined tellurium activities with regard to their behavior toward HasteHoy N
1 equilibrium mixture of C^Tejfs) + CrjTe4(s) 2 equilibrium mixture of NijTej(0j 41 at 7 Te) +
NiTe 077J(7I ^ 437 at Te) 3 equilibrium mixture of CrjTe 4(s) + CrTc6(s) 4 equibbriun lixture of Ni 3Te(s) + Ni(s)
The systems are arranged in sequence of decreasing Te 2
activity as determined by isopiestic experiments Typical corrosion experiments were contacted at 700degC for 250 to 1000 hr The arrangements were by isothermal gas phase transport of Te in previously evacuated sealed-off quartz ampuls by embedding the specimens in the mixtures and in the Cr2Tej-CrTelaquo and CrjTe4-Cr4Te6 cases by transport in molten salt
The most pertinent results are as follows
I Hasldloy N samples exposed to NiTej(s) bull Ni(s) (system 4) did not show intergranular cracking This is promising because if one a n establish a steady-
M l
dak luaawiun m which the telahaa activity is kwcr HOT OOI aefaed by das system staadanJ Haacaoy N wtl wot be eaaaittled
2 Sysaeas I awl 2 have teMaaa activities thai are loo high Ibex sysseas corrode Hasseaoy N sevcaeh water af the experiaeatal w w y a w i aad
3 Systea 3 fCrjTelaquolts) + CrTeraquoltsti SIUHH proaase as a iraariaa-deaivery actboa a aohea sansacc it B saffvseatry corrosive to cane aterpawatar cactoag of thk-caoy N b a docs aot fora acactioa layers
It is of value to note dot the systea Cr7Te(s| bull Ctls) has a tehaiaa activity that B mar lower thaa the systea NiTe2(s) fifs) l as systea abo is proa-isag since lagh surface duoaaaa aiebt be used a a tdariaa getter a the fas phase Experiments are water way to measure the telariaa activities of the above systems
611 OKRATIONOF METAL TEJXURJUM-SALT SYSTEMS
J R keissr J Brynesud J R DiStefaao EJLawrcace
The discovery of Jtatk intergranular cracking of HasteBoy N parts of the Molten-Sail Reactor Experishyment which were exposed to furl salt led to a research effort which identified the fission product tellurium as the probable cause of the cracking Experiments showed that HasteBoy N specimens which had been dectro-plaied with tellurium or exposed to telariaa vapor exhibited shallow intergraniaar cracking like that of specimens exposed in the MSRE Subsequently a proshygram was initiated to find an alloying modification for HasteHoy N which would enhance its resistance to teiu-rium The resistance of these modified alloys to crackshying is measured by exposing specimens to leaiirium vapor deforming them and then evaluating their surshyfaces by metallograpruc and Auger methods However the chemical activity of tellurium in these experiments raquo significantly higher than it was in the MSRE In order raquoo simultaneously expose specimens to the combined corrosive action of molten fluoride salt and telurium at a more realistic chemical activity a method is being sought for adding tellurium to molten salt in a manner that would simulate the appearance of lefurium as a fission product Experiments have been started that wia permit evaluation of several methods to determine whether they will produce the desired conditions
61 II Teaaraan Expcnacatal Pal I
Tellurium experimental pot 1 was built to evaluate the use of lithium telluride as a means for adding lefu-
riaa to safe Has pot laquoRg 632)aVws t d a a a lobe
BaaaaWC PJKBTBBH t a W t m a f f e a l tan a a r a n f H M K I BBBEBY a a a V aj w^ laquo ^ n i w araquovraquo ^ ^ p a t s waaaaajaa ^^a avaa BPUiawavww a a wuvu a a a i aaawaa
through Tefloa seals aad are used Or delect aad aeaa JK
14 The Nrtimdash laquo fan far As nacnacw raquo raquo fnfmt4 bully vannr t JHB ncaacny i mc ootiiuuucvKai B a M i i o o bull a t m4t traquo aryci raquo4 ) b M r
102
I bull UF-lef -ThF 4 (72-16-12 mdk mi m tern- A rfastetoy N pat was filed with the salt LiF-ftcfV latoSOTC ThFlaquo (72-16-12 aaok ) mi the temperature conshy
trasted at 700C After a sample of the salt had been lixTe which w pscpMcd hy the tafcea CrTelaquo was added mi a M I Hasteaoy N sheet
(Sect 31) hat i i i j two pdhsts specimen was inserted hMo the salt After 170 hr the a total of 0170 g of l i jTe were added to tjrrrwnrn was reamed and after 250 hr a salt simple
I of saw taocaoJwwkji enmamiua of the salt wax taken The teaaperatare was thea lowered to 650degC of oar ftadynra Chtaaitijr Draw gave aad a day user a sab sample was again takca This of the preseace of irlmiiia (Sect S3) xoacace was thea repeated at 600C Next the salt
dace aancIiiTepdkts west added aad te-ptrataie was rawed to 7O0C Cr Te was added a sawffc of Ae salt was takes for choanal analysis aad aaother Hastetoy N spedaaea iasertcd Ihe sped-Thre- addaaoas of CrF 2 totaling IJ2 g were thea a n was reasoned aad sah samples were tafcea under the aanle roauaed hy the aaaaaoa of theee awe li jTe same tjaw4eaagteratare coaditioas as discussed abouc
A anal iddirtja i nailing of 02 g of 10 was The two Hasteloy N spediaeas we submitted for Anger examination No were detected bat twdeace of tdariaai in the grain
foaad (Sect 612) The results of thr of the salt snaade are shown in Table
614 Tcaaraaa ooaceatratioas at 700C were not as bjgb as was expected bat the tact that some tct-irium was ia solution is deaaoastiated by the teHariam found oa the tpniannt Addrtioaal CrjTe was added to the
two salt samples were take lYriincaary that the soJatioa any not lane been
i the first series of salt samples was ulten the solafcarry measurements two tensile
icre exposed to the sah-CrjTcj solution Both specaaeas oae of rcfabr Hastcloy N and oraquo of lift Mraquo-07 Ti uwdrfied Hasteloy N showrd a
after 500 t_r exposare at 700C After iheregabr Hastetoy
N jpuinun was obatmd to lane agaificaatty more aad cracks than dhJ the modified Hasteloy N sped-
i (Sect 614)
r6M
611J
The adfciua of a CrjTty or CrgtTlaquo4 at anj stall aaothtr awaVod for
toaHaamMSMfanadtiraaesceai of ehraawam idhaldt is bullanafaajsi aat acttwiy of
at the adt wM he otnunaat pro-
To at which canter of thaat chro-
bullw wWwWwaPpPIbull VraW) ^ppaaar bull ajwPTff
of the chromta Mftaridat as s faac-
Tlaquoaa rnmauddNoanan M )
Moaa^aVStwMw bullnoTci After
OTe After
Ctlt tUHiam
im Tlaquo 5 0 4 4
Tlaquolt5 Cr7S
Tlaquolt5 CrlaquoJ
656 Tlaquo 151 CrIOS
Te75 Crl20
tan Tlaquolt5 rr
Tlaquolt5 OBJ
103
The experimental assembly is being used to expose standard Ifasteiloy N specimens to salt containing Cr Tej to obtain data on the extent of attack at 700degC as a function of time
611J Telwnum Expctunxwtal INN 2
When a technique for introducing telurium into salt at an acceptable chemical activity has been developed a method will be needed for exposing a large number of specimens to salt-tellurium solutions A Urge experishymental pot has been constructed for this purpose The pot has a stirring mechanism facilities for introduction of electrochemical probes and sufficient accesvi to allow dmulianeous exposure of a large number of specishymens Operation of the system will begin when a satisshyfactory tellurium addition technique is available
612 GRAIN MUNDARY EMHtlTTLpoundMENT OF HASTELLOY N BY TELLURIUM
R E Clausing L Heatherly
Auger electron spectroscopy (AES) is a powerful technique for studying grain boundary embrittlement of Hasidloy N by tellurium The recent development of the technique to permit AES analysis win a small-diameter (--5-fi) electron beam to excite the Auger elecshytrons of a specimen surface has made truly microscopic analysis possible1 5 The development of techniques for scanning the beam and the development of electronic data processing equipment have continued to be a censhytral pari of our efforts As the techniques improve our ability to see the details of the telurium embrittlemenl process improves dramatically We can now not only provide a qualitative image of the elemental distribution on intergranular fracture surfaces at a magnification of several hundred limes but we can aho provide a semishyquantitative elemental analysis as the beam it scanned along a line across the sample However it is not presshyently practical to provide a quantitative analysis along a line across an rntergranubr fracture surface since Auger intensities at each point OR a rough surface vary accordshying to topography This effect can be corrected in prinshyciple by a normaliation technique but data for each point must be normuhad mdrvKJuaRy and the present equipment cannot handk the volume of data required The data presented below are typical of several samples of lefluriurn-envbrittled HnHcRoy N that were examined recently These samples are being studied in various
15 R I ltlMlaquonf ami I Ikjihrrly VWT ftn^wm Srmi mmu rmtr Rrp fth J bulllt ORNI -5ltM7 p MM
pans of our previowtty outlined efforts to understand the tellurium embrtttkment of nickel-based alloys The sample chosen for the present discussior demonstrates our state-of-the-art capabilities and limitations and at the same time provides some new insights into the nature of the tellurium embrittlement of Hasteloy N
A sample of Hasteuoy N that had been exposed to tellurium vapor at low partial pressure for SOO hr at 700degC was fractured in the AES system and the resultshying fracture surface was analyzed using Auger electron spectroscopy The fracture surface is shown in Fig 6 3 3 The scanning electron micrographs made by Crowe reveal that intergranular fracture occurred along the edges of the sample and that the central reejon faded in a ductile manner One fairly large area of ductile shear can be seen Three types of Auger data presentations are used below imaging line scans and selected area analyses The first is qualitative while the second and third are progressively more quantitative
Figure 634 is an image obtained using the scanning beam in the AES system and the absorbed sample curshyrent to produce the image contrast It is similar to the scanning electron micrograph (la) but because of the larger electron beam and the different method for proshyducing the image contrast the resolution in Fig 654a is poorer and some distortion is evident Nevertheless it is relatively easy to correlate the features shown in Fig 634a with those in Fig 633a Figure 6346 is an image of the same area shown in Fig 634a but with image contrast produced by the tellurium Auger signal A careshyful comparison of the areas of high tellurium concentrashytion with the areas of intergranular fracture shows that a good correlation exists between the two No telurium can be detected in the regions of ductile or shear fracshyture Figure 6 3 5 b a series of line scans showing the peak-to-peak intensity of the Auger rignah for nickel molybdenum chromium and tellurium as the electron beam was scanned along the path shown by the bright line Hi Fig 654a Some of the observations that can be made are (I) The intensities of the Auger signals are influenced considerably by topography that is some features such as the shear region between feature gt and the ieRuriumlaquombrittled region below it show lower Auger emission for al dements (this dependence on topography accounts for much of the jagged nature of the line scant 12) The lefurium concentration is quite high in the region of mtergranuiar fracture near each original surfaor ltJ| There is a definite tendency for the concentration of molybdenum to be higher in the regions of intergranular fracture (41 The nickd and chromium concentrations are in approjumatety the same ratio throughout the scan
104
ltaraquo 2nox ifrgt sonx laquorraquo nmraquolaquo wgt torn lto jonox Tt
105
Y-133510
Crack
Te Ertrittled
I i raquo i gt MICffOftS 375
j j TTT90raquoi i i S i i i r r i I005 INCHES 0015
F fcM MI l i w u i rtmw bull laquo raquo laquo gt mm to raquo AES Fht brnrfii wiiiul law dnraquoraquo the path irf ibr IMW laquo M 4laquol HJaMMrt ftftom in laquo fc-35 (M h M p e f otoMawajgiMM
NJ 4t M M n Aapjf bull bull bullgt pMaJwt nartmrt The onkriiiM fraai tuwJjiy ngtam m i to th
106
Traquo-laquo4T
Flj tSS Anger ajnJ Menrities for scans atony Ike path wdicXcd sn Fjsgt 6S4 The vertical axis is displaced and the vertical scales arbitrarily varied to permit a qualitative comparison of the variations of Ni Cr Te and Mo as a function of distance along the scan line The tones and features identified along the horizontal axri are also identilied in Fig 6_S4raquo and c The AES analysis of the regions bbeied area I area 2 and area 3 are given in Table 615
Another observation based on the detailed examinashytion of this and other samples is that the tellurium conshycentration hi the grain boundary is not a monotonically decreasing function as one proceeds inward from the original surface On nearly all of the embrittled samples examined thus far the tellurium concentration is uni-formnJry high throughout the embrittled area as for example is shown on the right in Fig 655 (The signal intensity on the left is strongly influenced by toposhygraphy- If this effect were removed by a normalization process Ms area would have a more nearly uniform composition similar to that on the right) The high relashytively uniform telurium concentration in the embrittled regions suggests that either a particular grain boundary phase of fixed composition may exist or that the tellushyrium atom fill all of the appropriate grain boundary sites in the embrittled region Sputtering this fracture surface (and those of similar samples) to a depth of a few atomic layers (3 to 10) reduced the tellurium conshycentration to below I at showing that the tellurium is concentrated very sharply in the grain boundary it is
therefore unlikely that the tellurium present in the grain boundary exhibits the properties of a bulk tdluride The molybdenum concentration remained high during sputtering operation indicating that the concentration of molybdenum is high in the bulk phase perhaps in a phase that has precipitated in the grain boundary
Table 615 shows quantitative selected-area analyses made in the three regions of the sample indicated in Fig 654c The compositions have been normalized to equal 100 at in each row The three rows for each area are obtained from one Auger spectra but some elements were ignored in the first two rows to make changes in the relative amounts of the other elements more obvious These results confirm the above conclusions and show ( I ) that tellurium is present in relatively large amounts in the embrittled regions and (2) that area 3 which is near the extreme of the depth to which the tellurium penetrated contains about as much tellurium as area 2 which is located near the center of the upper embrittled region Regions 2 and 3 are both enriched in molybdenum and carbon M indicated in the line scans
107
r4IS Cuaiummnofi ofaHamdmyNa
tor Suffer at 7 laquo r c
Rezwn Composition in laquo5r
Ni Mo Ct O
Composition in the lower repon area 3 imiertranitU fracture)
Cohipositioi in ocntral region area I (dacine lnlaquoiuregt
Composition in ike upper repon arcs 2 imlergwiutar fracture
70 1 11 M 1 10 9 40 II 6 6 75 16 9 75 16 9 61 13 8 64 25 12 58 23 II 8 42 17 8 6
33
13
I I
Areas identified in FBJ 6-54r The composition in each row is normalized lo cquai 100 at ri The three rows
lor each repon are from the same data but are normabted so as to make changes bulln retain amount of the dements more obvimn For convenience and consistency in repot inc data we astame the AF5 spectra tfaol Pabnbetf et aL Htndhook of Anger Electron Spectroscopy Physical Electronics Industries Inc Fdiru Minn I972l are accurate and directly applicable to our data Elemental sensitmwes are taken directly from the spectra presented m the handbook with no attempt lo correct for chenaca effects line shape matrix effects escape depth or distribution of dements as a fraction of depth in the sample The analyzer used is Varian model 981-2707 operated with an SOOOeV electron beam energy
The above results suggest the need for a detailed examination of the causes and effects of the high moshylybdenum and carbon contents in the grain boundary region and abo an examination of the irnphcations that the presence of a two-dimensional tellurium-rich grain boundary phase may have on the time dependence of tellurium penetration into the alloy
613 X-RAY IDENTIFICATION OF REACTION PRODUCTS OF HASTELLOY N EXPOSED TO TEIXimiUMCONTAlMNC ENVIRONMENTS
D N Braski
Hasteiloy N and several modifications of the alloy have been exposed to tellurium to determine their rda-ive susceptibilities to intergranular cracking Different nethods for exposing samples to tellurium have also
been studied in an attempt to develop a suitable screenshying test for the alloy aVvctopmenl program Some specishymens were exposed directly to tellurium vapor at 700degC while others were subjected io attack by nickel or chromium teBurides at 700 and 750V respectively This section presents the results of x-ray diffraction analyses of reaction products producerl during the tests Knowledge of the reaction products akts in evaluating a
given method of tellurium exposure and may provide information relating to the mechanisms of intergranular cracking
A number of Hastefloy N tensile specimens and flat x-ray samples were exposed to tellurium vapor at 700 SC for 1000 hr in an experiment conducted by Keimers and Valentine The specimens were positioned in the top portion of a long quartz tube having a smal amount of teiurium at the bottom The tube was evacuated backfilled with argon and placed hi a gradient furnace with the specimens at 700C and the trtiiium source at 440C With this arrangement teuurium vapor diffused upward through the tube at a rate dependent on the temperature difference between the specimens and the tellurium CM)Xgt5 mg TehrV At the end of 1000 hr exposure the specimens were covered with a very fine hairlike deposit similar to that observed previously in creep tests at 6 5 0 C 7 The results of x-ray diffraction analyses on these deposits are given in Table 616 The first alloy listed is standard Hasteftoy N while the other three have titanium and niobium additions The main
16 A D Keimers ami D Y Vatentme MSK Ammjm Semi IMII rrogr Rep Feb 2S 1975 ORNL-5047 pp 40 41
17 R F GeMhach and H HensonMSK hvpmm jViinwm frogr Hep An J I 1972 ORNL-4832 pp 79 86
108
TaUcfclt X-faydifTrartiMi malts fori IO0O brat 700 C
Hat number t lt aftoyinx
additions to nominal HasteBoy N composition
Method of tellurium expovire
Surface reaction products
405065 None kelmervVaknime experiment^
NiTe CtJe
472-503 M r Ti kctroerv Valentine experiment4
NiTe
470-835 0711 Ti 261 Nb Kebners-Vakn line experiment
NiTe CrTe
IK) 841 Nb Kdmers-Valeniine experiment
Ni rTe
474-533 201 Ti Brynestid low Te ac irrily exposure NiTets) + Nitsgt
NiTe unidentified substance
405065 None Bryncstad LiO + CrTe
N i T laquo + N i T e
V D Kdmersaad D Y ValentineMSR Fran Srmunnu Prop Rep Feb 28 1975 ORNL-5047 pp 40-41 J BrynestadVSR Prognm Senaamu Prvgr ltep Feb 28 1975 ORNL-5047 p 102
reaction product was NijTe 2 which was detected on the surfaces of all four alloys (NijTe was found on earlier samples exposed for shorter times in the same apparatus) X-ray lines which could be indexed as CfTe4 were also found on standard Hastelloy N and on the alloy modifkJ with 071 Ti plus 263 Nb The Cr jTe 4 interplanar spacing and relative intensities were calculated by H L Yakel Metals and Ceramics Divishysion from the crystallographic data in ref 18 The presshyence of CrTe4 in the reaction layer is reasonable beshycause both chromium and tellurium were detected pre viously on Hasteiloy N exposed to nickel telluriddes by electron mkroprobe analysis1 In addition chromium tdlurides were previously identified by x-ray diffraction on Hastelloy N exposed to tellurium vapor17
Brynestad20 exposed 2 Ti modified Hastelloy N specimens to a low tellurium activity (Ni3Te + Ni mixshytwe) at elevated temperatures The specimens were first placed in a quartz tube and the Ni JTe 2 + Ni powder mixture packed around the specimens The tube was then sealed off under vacuum and placed in a furnace at 700degC for 1000 hr The reaction products obtained in this test also contained NijTe2 but the remaining four lines could not be satisfactorily indexed to any of the
18 A V Berfaul G Rnull R Aleonard R Pauthcnct M CVvTctou and R Jansen Structure Magnet iqucs de CtX 4
raquoX = S SeTeh Phvs Radium hi)582 95 (1964) 19 D N Braski O B Cavin and R S Ctmae MSR Prltt-
gnm Semtannu Fmgr Rep Frh 28 1975 ORNL-5047 pp 10$ 09
20 J BryncMad MSR Program lemktnnu Pmtr Rep Frh 28 i975 ORNL-5M7 p 102
Ni Cr or Mo tellurides The unusually broadened x-ray diffraction peaks suggest that a complicated teluride such as Ni-Cr-Te may have been formed In another tellurium experiment Brynestad exposed a standard Hastelloy N tensile specimen to a melt of LiCI containshying Cr 2Te 3 (solid) at 50degC Some Cr 2Te dissolved in the LiCI melt and reacted with the HasteUoy N After 146 hr the tensile specimen was removed and the flat surface on one end was analyzed by x-ray diffraction The results (Table 616) showed that Ni3Te2 and NiTe0 were produced
In summary these tests have shown that the primary reaction product between Hastelloy N and tellurium near 700degC is NijTe X-ray lines corrsponding to Cr iTe 4 were also present in patterns from the surfaces of several Hastelloy N alloys exposed to tellurium vapor at 700degC Exposure of Hasteiloy N to tellurium at low activities (NijTe2 + Ni mixture) may have produced some complicated Ni-Cr-Te compounds in addition to NiTe2 as evidenced by the unusually broadened x-ray lines
614 METALLOGRAFHIC EXAMINATION OF SAMPLES EXPOSED TO
TELLURIUM-CONTAININC ENVIRONMENTS
H E McCoy B McNabb J C Feltner
Several samples of modified Hastelloy N were exposed to tellurium-containing environments They were deshyformed to failure at 2SdegC a procedure v-hich forms surface cracks if the grain boundaries are brittle a
109
metallographk section of each was prepared to detershymine the extent of cracking- These tests hawe two objecshytives The tint is to dewlop a method for exposing samples to leBurium to produce a reaction nte comshyparable to those anticipated for an MSBR This rate is thought to be a flux of teOurium of about I0 1 atoms cm 1 sec- The second is to compare the cracking tendencies of arious alloys of modified HasteBoy N
A new technique developed for measuring the extent of cracking is more nearly quantitative than that used previously In the new technique a mounted and polished longitudinal section of a deformed specimen is viewed on a standard metallurgical microscope The eyepiece has a fiar which can be rawed to various locatiom in the field being viewed The filar is attached to a transshyducer which produces an output voltage that is a funcshy
tion of the location The output signal is interlaced with a scull computer which WH on command compute crack lengths and several statistical parameters The information is displayed on a teletypewriter The cracked edge of the mounted specimen is scribed every 01 in_ and the operator measures a l cracks in successhysive 01-in intervals untl at least 30 cracks have been measured The computer then calcinates and displays the average crack length the maximum crack length the standard deviation and the 95- confidence interval A typical scan requires about 10 mm and is considershyably faster than other methods used thus far
The experimental conditions associated with the ten experiments to be discussed in this report are summashyrized in Table 617 The chemical compositions of the alloys studied are given in Table 618 In all cases the
T J U T pound I 7 Cenoal4cxiiftmm ofTe-HaMenoy N a y w t t
Experiment IXcsipna (km Experimenters Exposure
conditions Alloys
bullMinded Genera
75-1 Brynesud UCl + Cr Te for I 4 6 n r a l - 7 5 0 C
405065
75-2 Krimcrs Tc vapor for Valentine |l)00 bral 700 C 405065
470-835 472-503
ISO
75-3 Bryneslad 250 hr at65ITC 405065 pa-kedin( r Te 474-534
474-535
75-4 Bryncstad 200hraf 700 C packed in Cf Te
405065
75-5 Biyncstad 504 hr at 700 C 405065 Keiser in s i t bull Cr Te 470-R35
75-6 Brvnestad 000hra l700C with vapor above Cr Te 4
405065
75-7 Brvrrslad 1000 hral 700 C with vapor above Cr Te
405065
75-8 Brynestad 1000 hr at 7 0 f l T laquo i l h vapor above J gt nH-kel tellurides
405065
75-9 McNafcb 250 hi al 7laquofC in 405065471-114474-534 McCoy vapor above Tc al 474-5356006006263
300 C I H 237295 297 298 303305306345346 34734821543469-344 469-648469-714470-786 470-835
75-10 McNabb 250hra l700 C in 40506521543 345348 McCoy vapot above Te al
300C 4 1 1 4 1 laquo21424425
Heavy reaction lay en
Whisker growth evidence of inhomopenoas reaction withTe
Heavy reaction layers
Heavy reaction layer
Reaction layers
No visible reaction ayers
Shallow reaction layers
No visible reaction layers
No visible reaction layers
No risible reaction layers
See Table 618 for chemical compositions A D Kilmers and I) Y Valenlnc M$R Program Srmimmi FriffT Kip Feb -X V75 ORNI-5047 pp 40 41
110
t6lt
Heaimoabei Mo Cr Fe Ma C Si Ti Mb At Of her
62 134 752 a 020 0042 001 a 19 63 145 7 J 3 a 020 0135 001 a 25 l raquo 12 70 0040 022 0046 OJOI lt002 184 ISI IS 684 0054 0-23 045 001 050 185 003 W 237 20 67 43 049 0032 m 004 103 lt0-05 295 14 806 402 0 28 0057 lt002 lt002 085 0 0 5 296 15 809 396 028 0059 lt002 lt002 12 02 W 297 29S 303
2 1 20 20
70 70 70
40 40 40
02 02 02
0 0 6 006 006
002 0J02 0J02
024 lt00I
049
057 2J0 0J4
305 12 825 416 022 0072 009 088 I J 306 06 804 311 018 0065 027 001 OSS 345 IJO 71 38 026 005 022 002 045 346 110 67 37 018 005 048 002 049 347 20 7 43 025 005 047 lt002 088 34S 411 4 l i 42 424
20 20 20
120 120
72 70 70 70 70
007 a a a a
019 02 02 02 02
005 005 005 005 005
047 e a a a
lt002 a 1 0 219 18
042 115 113 104 134
007 010
42J 120 70 a 02 005 a 19 048 008 405065 160 71 40 055 006 057 lt00I a lt003 472-503 129 679 O089 lt00I 0066 0089 216 005 009 471-114 125 74 0062 002 0058 0026 175 a 007 474-534 1166 712 006 lt00I 008 003 20rgt a 053 014
0013 La 474-535 1179 730 005 lt00I 008 003 213 a 055 010 W
0010 La 003 Cr
600600 160 80 019 027 ltlnconcl600gt 469-64 128 69 030 034 0043 a 092 195 a 469-714 130 85 010 035 0013 a 08)) 160 a 470-835 125 79 068 060 0052 a 071 260 a 00311 Hf 40-76 122 76 041 043 0044 a 082 042 a 0024 Zr 469-344 130 74 40 056 011 a 077 17 a 0019 Zr bull21543 124 73 004 008 0050 0019 a 0 7 002
Not analyzed bur no intentional addition made of this dement
Not analyzed but nominal concentration indicated
sample was a small tensile specimen 56 in in diameter X 1 in long having a reduced section in in diameter X I in long All specimens were annealed I hr at I I77degC in argon prior to exposure to tefliirium The results of crack measurements and data resulting from the tensile tests at 25degC that were used to open the embrittled grain boundaries are shown in Table 619
Experiment 7S-I was run by Brynestad and involved a sample of standard Hastelloy N that was immersed in LiCl saturated with C r T e for 146 hr at 750degC The specimen formed a heavy reaction layer (Table 6 7 ) but lost weight (Table 619) Figure 656 shows that the reaction was rather extensive with some obvioia grain
boundary penetration which resulted in extensive crack formation in the deformed section The extent of reacshytion in this experiment was higher than anticipated for an MSBR and therefore it is not believed that the experimental conditions employed constitute a good screening method
Experiment 75-2 was run by Kelmers and Valentine and the detailed results were described previously2 All samples lost weight in this experiment (Table 619) Although the samples had more reaction product en
21 A D Kelmer ind D Y ValentineWW Program Smi-anmi Progr Rep hth 28 1975 ORNL-5047 pp40 41
Tabic 619 Inlf(granular vracfc formation anrt loniU propcrD of raquomnllaquoraquo oPlaquoraquovd In ulltMlum and ilralnad lo faHurv al 25 V
ffimmti H M I MMttof
CilaquockiMui k |0gt
C m k t f w C i K k t c m
D t p In ) SlWMbi 4fvulMgtn
1raquogt
CMflOIIWt W I U M I
I M I
W f laquo k l bull lung lmlaquol
VMM t u t u
ltbullbull rail
U I W M I f M M HltMH
t l O 1 ptl)
f l M I I M f H l t U
lt I 0 p i l l
U m f w m f lMUt lWH 4 I 0 ^ I raquo
P l M I W f HIM
K n l i w i i M M M M
11 MMraquofclaquo
H M I MMttof CilaquockiMui k |0gt
C m k t f w C i K k t c m A M I i f M W I R H U H
SlWMbi 4fvulMgtn
1raquogt
CMflOIIWt W I U M I
I M I
W f laquo k l bull lung lmlaquol
VMM t u t u
ltbullbull rail
U I W M I f M M HltMH
t l O 1 ptl)
f l M I I M f H l t U
lt I 0 p i l l
U m f w m f lMUt lWH 4 I 0 ^ I raquo
P l M I W f HIM
K n l i w i i M M M M
11
5 1 40505 ) | lgt 111 101 lt 1 7 1 4 ) 1 I T 4 1 1 1 4 ) M i l gt I 4 HI raquoJ-1 4 0 5 0 5 5 ) 0 1 1 4 t gt 7 5 7 1 1 1 4 5 1 0 SI 7 1 ) 4 7 I I 71 4 0 4 4 1 1 43 1
470-1)5 17 A t 1 7 7 0 I S 4 4 1 1 1 7 7 1410 l ) t laquo 4 1 5 44 0 ) S ) 4 7 ) 5 0 ) 100 I I I gt)) raquo7 0 1 4 I I sraquolaquo 1 5 ) 1 1 1 ) 0 ) l lt 4 0 4 410
iao t ) 15 1 4 ) 0 1 D l A l 47 5 4 5 1 1 4 ) U S I M l ) t 1ST 7 5 1 40515 140 laquo5 17 1 4 1 1 0 17 117 4 7 uto 1 0 0 4 0 1 414 4 1 4
474lt5)4 110 17 145 1 7 4 5 1 4 145 S t 114 0 1 0 0 411 441 S I T 4 7 4 5 ) 5 1 ) 0 bull I 1 0 ) M 4 5 4 1 1)1 4 S 4 not laquo 7 4 7 4 lot S 4 )
7S-laquo 40505 4 1 0 5 7 0 11114 l raquo ) S l 1 1 1 1 1 1 ) 5 11 ) 15 1 bull raquo I 7 7 1 1 ) l 44 1 44 0 10) 7 I N M ) H I 1 1 1 gt I 0 ) ) i ) 1 4 4 1 4 4 1 0 7 5 5 405115 170 14 4 1 5 raquo 0 I S S 1 bull 0 1 5 0 111 1 1 1 7 ) gtS ) 7 1 1 1 1
4 7 0 laquo J J 10 71 ))) 14 7 1 0 1 I t S I 5 1 1 I M 1 I M 7 17 0 ) 7 1 1 4 7 - 40505 115 15 I ) 1 1 4 1 ) 1 4 4 0 bull 001 S i t 1 1 1 ) 1 1 7 1 4 0 4 4 1 0 ))raquo 7 J 7 40505 510 )ogt 4011 1 0 1 4 1SS k i t 1 1 4 ins ) I 7 ) 4 ))gt 7 ) 1 40505 ) 0 141 5 5 bull lll 1 1 7 ) )raquo) Sl l 1 1 ) 1 1 1 7 4 4 0 0 414 5 1 7Jraquo 40505 H O 141 4 1 7 5 ) 151 I I I 7 5 1 1 1 7 ) 1110 M S 41 1 gtraquo4
4 7 1 0 1 4 l i 7 ) ) 7 4 )laquo I D 4 4 bull 1 4 4 7 1 1 ) 4 105 0 laquo raquo l 5 4 1 4 4 4 7 4 5 ) 4 ) 0 14 1 1 5 4 5 5 107 ) 1 7 I t l i t 1114 4 gt gt 45 S 411 15 140 I S 10 1 J M raquo l J7 0 5 1 5 1114 I D ) 4 t ) 4 1 ) 4 7 t HI 15 10 1 7 1 U I laquo I I bull ) 0 )raquo 1 0 1 7 4 U l gt 7 I S T )
M S 100 )raquo )raquo 4 l 1 1 1 1 4 bull 0 7 1 1 7 I I 1077 M l 41 I 4 raquo ) H t i l l ) 1 0 7 441 100 ) S bull 0 4 551 I l l 1117 41 1 44 7 4 7 1 M l 4 l I S ) l i 0 ) M l 1 1 ) 4 1075 4 1 5 4 5 511) J41 170 0 raquo I I I ) 7 ) l i i bull 1 S l l 1)1 1 l l t l 4CI 4 ) 1 4 ) 50 450 177 11 o 1 7 7 ) i i bull 0 1 too 1)00 1 1 1 17 4 4UI 4 ) 4 50) 450 l lt 1 4 1 1 raquo l i bull 1 1 I t 1 111) 1100 471 445 4 0 raquo 7 J i l l 111 1 1 0 4 1 0 1 1 u bull 1 1 t l 1 l i t ) 1 1 7 1 ) S gt ) T 4 4 1 5 15 15 10 10 1 1 7 ) i s 1 5 5 ) 5 1 1 ) 1 I M S 4 gt ) 4 4 4 4 4 1 )7 IS )) 14 1 ) I S I S i 0 5 1 4 l i l t I M S 4 ) 5 4 4 ) 4 4 505 H O 141 I t ) 1 7 1) 1 4 bullUS 5 ) 1 D t S 1 1 7 ) 4 4 1 4 1 4 7 7 M l 1)0 D O 1 7 ) 107 bull 4 1 1 bull 0 4 7 1 ) l l ) t 1104 4 1 7 4 raquo 4 7 11 110 17 1 7 1 1 1 7 ) 7 7 4 M I 1171 m i 4 1 4 4 S I M S ] 10 11 1 gt 1 4 0 4 4 5 IS 1 5 4 7 117) 110 1 4laquoT SOT 4 1 1
) 440 17) 117 1 7 S ) 1 I S l l l ) ) 4 111 7 gt J ) ) l o 41S 4 4 4 1 ) ) 0 1 ) 0 I I I 4 ) ) 7 4 1 bull 0 1 I I 1)1T 117) 4 ) 7 4 1 445 4 7 | 4 1 ) )) 114 5 0 4 1 1 4 5 bull 0 0 1 4 1 1117 l i t ) 8 ) 7 Hi 4 ) 4 4 7 0 O J ) )bullbull 1 1 4 7 SO 1 0 0 ) 5 5 IJ75 1)04 414 477 4 5 4 7 0 7 t )) 1 ) 1 ) 1 5 7 1 14 S 7 ) 0 ) 4S l i t 7 1 0 7 ) 5 0 4 S I 7 40 1 4 5 4 4 )raquo 141 l 171 V I 1 ) bull 0 07 5 1 7 1 ) 1 1 1 1 0 ) I 0 ) raquo 7 414 4 1 1 5 4 ) bull5 )) I I 1 4 4 4 1 17 11 45 4 not M I MT 5 7 )))
75 10 40505 M O I ) ) 177 4 1 ) 7 1 1 bull 0 0 4 5 ) 1 1 ) 1 4 1 1 ) 0 4 0 4 gt I 4 4 0 415 ) 0 0 I I I 17 1 54 1 I I 1 4 1 bullOS S l l l i t a 1 1 7 4 7 411 411 415 140 5 1 1 7 5 1 0 1 ) 4 ) laquo 0 0 l t i l l i t ) I I I ) 4 1 ) 410 4 7 411 M O 1)5 M4 raquo0 l 1 0 1 1 4 0 0 ) sso 1 1 7 111) 4 ) 7 4 5 4 4 1 4 414 4 ) 0 1 1 7 501 14 1 0 0 ) bull 7 4 l ) raquo ) 1 ) 1 7 44 1 411 gtbull) 11 101 1 1 17 1 0 54 0 74 bull0 1 1 ) 4 1111 1 1 ) 0 4 7 1 SI 1 1 1 7 15 M 10 I I I 1 5 1 ) l bull 0 1 5 ) 4 m i 1117 4 1 4 4 4 4 47 ) 541 M 1 ) 1 1 M l 71 15 bull 5 4 1 i n 107 1 44 1 4 7 4 54T M 5 15 5 raquoraquo 141 gt) i n bull 0 0 1 5 1 1 1 4 1074 4 4 ) 4T4 4S4 415 M 11 105 117 5) I S bullooi 5 ) 0 i n I IS S H 4 4 44X1 411 1 ) 141 ) 5 laquo 1 5 1 bull 14 4 1 1 1 1 ) 4 bull T I S I M l 5 ) 4
4 1 1 5 4 ) 17 7 10 1 ) 7 I I gtraquo bull 1 4 7 ) I D 1014 S I ) 1ST 5 ) 7
4laquou i MM tun bull 15V al bull tiiaM M M ul 0044 Mgt 1uUl laquomlil raquof yfmmtri 1 1 l o t 1 )
112
raquo gt laquo laquo bull
(b)
pornnaof
0-010 in 0 25
U t a M H I i th) tdft oi ureaed poriioa of 1
llaquowraquoCr Tca i7Mrci IflOX
HkrltlaquoiE ytoT
one end than the other the extent of lt icjaunably uniform Typical plsotonucrognphs of the (oar materiab are shown in Fig- 637 Aloys 40506S (standard) and 472-503 (216 Ti) formed extensive cracks but aloys 470435 (071 Ti 260 Nb) and 190 ( I J49 Nb) were considerably more resistant to cracking
in experiment 75-3 three samples were packed in CrTe grannies for 250 hr at 650degC The samples formed heavy nonadherent reaction products and lost weight (Table 619) All three materials formed extenshysive cracks (Table 619 Pig 638) with the depth of cracking being slightly less in the two modified alloys (474-534 and 474-535) than in standard Hnstdfoy N (heat 5065) However the extent of reaction is too high under these conditions for the results to be meaningful
bi experiment 75-4 duplicate samples of standard HastePoy N (405065) were packed in granules of CrTe4 and heated 200 hr at 700degC The samples formed nonadherent reaction firm and lost weight tarshying the test (Table 619) The reaction layer and the
the reaction rate was un-of the exposure cnadnioni as a
bull Fig 639 reasonably high for a
k experiment 75-5 Iryneslad and Keaer two specimens to MSW fad carrier salt (c uranium) that was saturated with CrjTcj The exshyposure was for 504 hr at 700C These samples formed reaction layers but lost weight (Table 619) As shown in Fnj 660 both uatcinls formed reaction layers but in heat 470-835 (071 Ti 260 Nb) there to be less penetration of the rcactants aVng the | boundaries The standard Hastdoy N had regions where layers of grams dropped not during the exposure The number and depth of cracks in the sliessed portion of the samples were less for heal 470435 than for stanshydard Hastcloy N but both materials formed extensive intergranutar cracks
Since the samples packed in the various telurides reacted extensively several experiments were run Hi which the samples and the teluride were separated in
113
(a)
(b)
(c)
- r - raquo
(d)
0 25 MI FfcS7 SywiwuM fcmdasht tfmmmm IS-l wfcMl wmdash laquo y mdash lt iraquoraquofciraquo raquo w laquo r f p w raquo o r irtNilmi far I W H m 7 W C n i
NralltOAraquo5tfrlfcril4-Slttilt I TiM Ilwtf 47MJ5 llraquo7l-lt Ti lA SbKultkat MRi lA f r Hbt AlaquopoMwl lOOx
114
(c )
(laquo )
(f) raquo bull O O W f
0 2 S laquo raquo
fplusmn S Ipniawn tnm rxpummM 75-3 Packed m CrTe granules for 250 hr al 650 C and deformed lo fracture ai 25 f flaquoraquo Heal 405065 Msireaed thy hear 405065 Urevwd tei heat 474-534 (2091 Ti 00131 Lagt imlaquorclaquoed (ltraquo heal 474-534 tlrcuedfrgt hear 474-535 (2131 TiOOH La 0031 Claquolunlaquoreslaquodlt1 heal 474-SJS laquorevd Atpnnshed lOOx
115
3ampF
bull 025am bull
the reaction capsule In experiment 75-6 standard Hasteuoy N was reacted with the vapor above CrTe 4 at 7000 for 1000 hr The spedmen pined a amount of weight (Table 619) did not form a reaction layer (Fig 6J6I ) but did form extensile inter-granular cracks (Fig 6 J 6 I Table 619) Experiment 75-7 was run in the same way but Cr 2Te was used The sample tost weight formed a surface reaction prodshyuct and formed mtergranutar cracks when strained (Table 619 Hg 662) In experiment 75-8 the source of tellurium was two nickel leRuriJes fc and 7 i The specimen lost weight did not forn a TJIMC surface reaction producl and did form rnieigranubr cracks (Table 619 Fig 6J63)L From these experiments it was concluded that the tellurium activity produced by Ct Te 4 was likely that best suited for screening studies
ExpeiHMnt 75-9 included 25 aloys which were exposed to tellurium vapor at 7000 for 250 hr The weight changes covered a range of +84 to 74 mg with no obvious correlation between weight change and crack depth or number (Table 619) These specimens were sealed in four different capsules for exposure to tellurium and there were differences in the extent of discoloration of the samples These differences are likely associated with slight differences in the extent of reaction due to variation of the temperature of the tellurium metal in the various capsules Thus it is quesshytionable raquo to how far one should carry the analysis of the data from this experiment
Owe further problem coacernmg data analysis which applies equaly w d to afl data sets is the baas that should be used for comparison The number of cracks ami their average depth are two very important paramshyeters However it is possible that a Tprrimrn cm have a large number of shaaow cracks ( e ^ beat 63 Table 619) or a few rather deep cracks (eg heat 62 Table 619) The formation of intergranuiar craci of any depth is important because this may indicate a tenshydency for embrittlement The depth of the cracks ts important because this is a measure of the rale of peneshytration of tefurium along the grain boundaries Howshyever for a relatively short test time (test 75-9 (2S0 hr)) the formation of numerous shalow cracks may be indicative of a near-surface reaction which wil not lead to rapid penetration with time Obviously longer-term tests are needed to determine the rate of penetration of tellurium into the metal
On the basis of number of cracks formed the alloys in experiment 75-9 which formed lew than 40 cracks per centimeter were 345470-835421543 237469-714 470-786 62 295 and 348 The alloys forming cracks with an average depth of lt 127 u were 63 469-714 295 348 469-344 421543 and 470-835 Several of the alloys appear good on the basis of both criteria These alloys all cont in niobium and several contain niobium and titanium Another parameter used for comparison was the product of the number of cracks and the average crack depth The alloys from expert-
l i t
( bull )
laquo
ltlaquov
(c)
lt)
I 0 2 9 raquo raquo gt Figt iuM Senates from uteiiaini 75-5 Sanpln exposed to feci all sraraKd laquo-iih Cr Tc for 504 hr ai 700C and strained
lo fraclarc al 25T ltraquo Standard HasteHor N bullntlrencd shoaMer (Agt standard HasteHoy N stressed p(c length sfoning region where grains were urn dnrine tall cipotnre (lt-gt heal 4704135 10717 Ti 260 Nb) oatlrroed thoakitr ltltgt heal 47f 4J5 stressed portion Aspotahcd I00X
117
(a)
(b)
l f l laquo Q l n - | I 0 2 9 M I
Flaquofcl TtiMwi lUmBij X ( h w O W I I w lono br mi earned to fjUarc ut F4pr of MM icwd pvnna iraquo lt
1154k ampMOftrtrfKMe4 lo the of tiinaei porno As pufcihfi
CrTlaquo j i7laquorCfof IflOx
ment 75-9 are ranked on this basis (Table 6J0gt Stan-dard Hasidoy N raquo significantly different from al other heats on this basis There are latfe variations among the other heats but it is difficult to pick out general trends on the basis of niobium and titanium concent rations
Several typical photomicrographs of samples from experiment 75-9 are shown in Fig 664 No reaction films were visible on any of these specimens The picshytures show dearly the wide range of cracking experishyenced by the various heats
The mechanical property data show small but signifishycant variations in the yield and ultimate tensile stresses of the various heals (Table 619) The higher stresses are grnerolly associated with the alloys containing the higher amounts of niobium and titanium However the
high fracture strain and reduction in area for a l h-ais indicate that only very small (if any) amounts of gamma prime formed during the 250 hr at 700degC
In experiment 75-10 steps were taken to ensure that the specimens were at a uniform 700degC and that the tdurium was at 300degC The weight changes were very erratic and show no correlation with the number of cracks or the depth of crack formation (Table 619) A sample of heat 425 was included in each of the two capsules used in tins experiment to obtain some idea of reproducibility The reprodudbflity was reasonably good Samples o alloys 405065 298 295 348 and 345 were included in experiments 7 5 4 and 75-10 Heats 405065 298 and 345 in experiment 75-9 cracked more severely than in experiment 75-10 Alloy
l i t
V - t
(b)
I AW hr art in
021 uigtiiiwil75-7 iioafAtlaquo4acor A
Cr f e j i ltKraquo lt t t HMta
laquo bull - - Craquofc
ltW SS^j-^n-raquobull
WMMMCS at ItXfC foe IWO hr aa laquo u m lt lo f IflOx
0 2 9 laquoMi itmtm 7W San phi r^puraquorf to Ike
to) Mat of mmiiwmtd porta raquogt claquogt laquo tf bull gt mcfcd
puftimi A ^riuhfd
IN
ITS
note bull bull laquo tat tract tdncti0c4 I cy
roat i
H m i oaccatraaoa t 0
( - -
I cy
roat i
H m Ti Nb (Mm
5laquon 4ltI5laquoraquo5 371 3lraquo 0 3 5 027 Si 3195 474-534 2 4 9 01013 U 27 JO 471-114 175 247 303 049 OM 2400 3ttS OM 13 2249 29S 20 217 3 2-5 2 1 29 024 0 3 7 1993 347 raquoM 0 4 7 Si 1924 4S14M 092 195 I9 IO 474-5J5 213 0 4 4 L raquo raquo pound r IBSI M U M P27 15 C i 1453 I I I 050 l-SS 1304 344 04laquo 049 1292 49-344 077 17 9 9 345 045 ft22Si 4 M 237 1J03 409 49-714 0S0 tJampO 352 2 1 9 raquolaquo 4 7 M 3 5 071 IM 290 421543 07 179 4707S 082 0 4 2 101 295 0 M 3raquo 34S 062 047 Si
Set TjNe 1H lw drbiM cheiwcJ jiulvcs
348 was less severely cracked in experiment 75-10 and Nat 295 reacted similariy in both tests Such differshyences emphasize the importance of duplicating test results before making important conclusions
The alloys in experiment 75-10 that formed lt32 crackscm were 413 34 295 4 1 1 421543 and 345 Those with average crack depths s 109 p were 421543 295413 345 and 298 Again this ranking is of quesshytionable value because alloy 298 had the shallowest cracks of the 12 specimens but formed a large number of cracks In an effort to combine the factors of number and depth of cracks the two factors were multiplied and the alloys ranked as shown in Table 621 There is a very large step between alloys 425 and 298 and the better alloys appear to be ones containing from 045 to 20 Nb with titanium additions of 1 ^ or less
The tensile data show small variations but do not show evidence of embriitiemeni due to gamma prime formation during 250 hr at 700degC (Table 619) In specshyimens from experiment 75-10 the wide range of trackshying behavior is apparent (Figs 665 and 666)
These tests have shown that several methods are availshyable for exposing metal specimens to tellurium The metal tefluride Cr Te 4 has an activity most consistent with our estimates of tellurium activity in an MSBR Specimens can be exposed to salt containing CrjTe 4 or exposed to vapor above the compound Tellurium metal at about 300degC has a vapor pressure of about I X 10 4
torr and appears IO provide a tellurium activity comshyparable to that expected in an actual MSBR The specishymens exposed thus far show that niobium is effective in reducing the extent of iniergranuiar embrittlemenl of Hastelloy N
615 EXAMINATION OF TeCen-l
B McNabb H E McCoy
The TeGen series of capsules was designed for studyshying the effects of tellurium and other fission products on metals The fuel capsule is a Vi-in-OD X 0035-in-wall X 4-in-long tube segment of the metal under
120
( c )
I OOIOf - _ I I J 0 2 9 M I
Fagtfcj64- CumdashjMiiun of imdashapamdashtm cmfcif bull l l i jNluj H lyye aBoyraquolaquoaoraquod wgt partial aitmdash11 erf tdNrimdash of 10 vm fat 250 br at 7WTC aad iliaan lo fraroarc at 2SC ltlaquoraquo Standard Hasfcttoy N that 4O5065i (142 crjckwrn a depth 416 raquoraquo IM modified Hastcfloy N containinc 08S^ Nb (aNoy 295) (10 crackson a depth 101 raquogt laquorgt modified Hastdloy N conlaaunK 082^ Ti 0427 Nb (alloy 470-786) (13 crackscm a depth 86 it 00x
Table 6 J I Rmdashfciwiof materials from expuimoH 75-10
Product of number of cracks and average epth
rnns) Alloy
number Concentration CJI
cracks 1 x rntci cm
epth
rnns) Alloy
number Ti Nb Other cracks 1 x rntci cm
4512 424 18 134 3245 421 219 104 3198 425 198 048 2328 405165 2157 425 198 048
713 298 20 336 413 10 113 209 348 062 047 Si 133 411 115 106 295 085 76 421543 07 45 345 045 022 Si
See Table 618 r detailed chemical aiulyicv
121
ltd)
( f )
I 0 2 5 M B I
Ff 65 Miami tpwmriw from expuwww 75-10 SpccmKru were cxrvwrd f-r 5n hr ji nn lt- ilt ihr apltlaquor iNiw irlluintm meiil JI nit C bullgt All- 424 iM jllgtgt i i rIjHn 45 II allot 4050 in allm 45 (gt alloy ^gtraquo A pohthrd Wfr
122
-1MS7t
(f) laquo0fllQH -
025 mm Fig 666 Stimti specimen from experiment 75-10expoatd tot 250 hraf 700Cfo fherapor above idmriwn meM it 300degC
(j) Alloy 413 (ft) alloy 348 ic)alloy 411 Irfraquo alloy 295 (ltbull) alloy 421543 if) all 345 A polithed IOOx
123
study The capsule is partially tilled with the MSRE-type fuel salt and irradiated in the ORR to produce fission products
The first experiment of this series involved fuel pins made of Inconei 601 standard Hastelloy N and type 304 stainless steel and the irradiation time was such that the amount of tellurium produced per unit area of metal in contact with salt was equal to that at the end of operation of the MSRE Some of the details of the postirradiation examination were described preshyviously2 2 A typical fuel pin is shown schematically in Fig 667 The segments marked A w re subjected to tensile tests using the fixture shown a Fig 668 The mechanical property data obtained roai the rings and the results of limited irtetallograpic examination were reported previously2 z More detailed mctallographic studies have been completed during this report period The segments marked B were used for chemical studies The salt from each segment was analyzed and the fission product distributions on the tube surface and a short distance into the tube were determined from two successive leach solutions The first leach used a verbodt solution (sodium vtrsenate boric acid and sodium citrate) which should have dissolved only residshyual salt from the metal surface The second solution was aqua regia and the time was sufficient to remove about
11 B McNlaquohb and II I McCoy IfSR Pnrmm Sununnu Pnifr Rip Feh gt tv~ ORM-5ltMpp 12 6
I mil ot the tube Both solutions were subjected to various chemical procedures to analyze for various nuclides and elements These results are partially anashylyzed and the results for tellurium will be discussed The tube segments marked ~C were retained for posshysible future studies
61 SI Metafognpaic Observations
Photomicrographs ot the three materials in the un-deformed condition are shown in Fig 669 Numerous voids were present near the surface of the Incopel 601 specimen to a depth of about 02 mil Voids were likely caused by the removal ot chromium from the alloy via reaction with U F 4 in the salt The Hasldloy S vrction shows no evidence oi chemical reaction with the salt The type 304 stainless steel shows some grain boundary attack to a depth of about 0_5 mil This was likely caused by selective removal of chromium along the grain boundaries The features in the type 304 stainless steel appear much like shallow cracVs and may have influenced the number of cracks that were observed in stressed samples of this material
Composite photomicrographs of the Inconei 601 rings after straining to failure are shown in Fig 670 Rings 2 and 4 from near the salt-vapor interface exhibit some evidence igt( attack but the other samples are almost entirely free of indications of chemical reaction
Photomicrographs of the deformed rings from the Hastelloy N capsule are shown in Fig 671 The count
olaquoM-oac n-ot
TTPt DESCRIPTION M O USE
bull VW bullbull IMG FOR HCCMAWCAL PROPERTIES
B fOU L E A C N (2 STEP
C StCTiQM TO K RETAINED
mdash EH0CAR
mdash A - i
4 -2 A-3 AN0 SALT LEVEL
z~ -laquo A-5
- S A-4 A - mdash C
mdash A - a A - raquo
mdash A- IO
mdash C
mdash A - M mdash A-12
mdash C
mdash A-13 mdash A-14 mdash A-15 mdash 8 mdash A - W mdash EMC CAP
f 667 Schematic docram of individMl feci pm jhowing the locaftoMof tat specimen
124
metaliographic sample indoles the fracture and an adjacent segment Since the fracture occurred at difshyferent locations the metallographic specimen contains varying amounts of inhomagcneously deformed mateshyrial For example Fig 67 I f includes a very small segshyment of homogenously deformed material whereas Fig 6 71 includes a relatively long segment As shown by the photomicrographs in Fig 671 and the data in Table 612 specimens from the vapor region (2-A-I) the salt-vapor interface (2-A-2) and rite bottom of the salt (2-A-l6) cracked most severely Three samples from other locations formed shallower cracks It is not known whether these differences are significant
Typical photomicrographs of deformed rings from the type 304 stainless steel capsule are shown in Fig 672 These specimens located on the inside surface had shalshylow cracks with an average depth of about 04 mil (Table 622) These cracks were rather uniformly distrishybuted in the samples from all four locations As noted in Fig 669 the unstressed specimen also contained cracklike features having a maximum depth of about 05 mil Hence the cracks in the stressed specimens may simply be the result of furti opening of features that are likely related to corrosion
6152 ClKiMcal Analyses for TeBormm
The lube segments designated B-l B-2 and B-3 in Fig 667 were subjected to several types of chemical analyses but only the results for tellurium have been analyzed in sufficient detail to report at this time The results for the three pins are shown in Tabic 623 The
Ffc668
0 Fixlare for ft leatinj rinji
of crack frequency shown in Table 622 was made in an effort to detect significant differences in cracking among the various specimens These counts are subject to numerous problems the main one being the inhomo-geneous distribution of strain within the sample In deforming the ring specimens in ihe fixture shown in Fig 668 the small portions of the ring located between the two parts of the fixture likely deformed very unishyformly but this length is very short relative to the total length The part of the ring that contacted the fixture likely deformed in some areas but was restrained in other areas by surface friction from the fixture The
Taate 6 J2 Smmmmy of crack frequency aad depth inToflMtiM for riant from TcGea-1
facts alaquo W M M t ID ratae at 25deg C
from TlaquoGCM fad Specimen nu iber
Crack frequency
(crack sin)
Crack depth (mils)
Average Maximum
2-A-l 480 080 20 2-A-2 450 II 22 2-A-4 410 060 12 2-A-5 480 058 12 2-A-8 MO 046 10 2-A-l 6 380 14 25
Type 304 (taMeu tted
1-A-2 160 04 12 3-A-4 310 042 10 3-A-8 260 036 10 3-A-I6 202 037 10
125
(a)
-J
(b)
(c) 20 40
- L - 1 _ 0001
60 MICRONS lt00 mdash SOOX -
laquo20 40
INCHES COOS
Fjj 669 Undeformed rings (ample No 9) from each TeGen fad pin near the middle of the fael aalL (a) Inconel 601 (ft) HuMelloy N(r) type 104 ttainlets jteel A polished 500x
600 inn
Ffc 670 Sample from Incond 601 fad put from TeGcit-l Kir failure al 25deg0 Portion of specimen exposed to fuel salt is on the I location A A (laquo) location A-5fr) location A-8 () location A-16
BLANK PAGE
Sch figure
j J u i u m l i i -Mi iWWLltLiWHt
126
a ten from (he location shown in Figr 667 and deformed to tide of cacti figure it Location A - l tftgt location A-2 ( r )
J
127
I Fig 671 Samples from Hwribr N fuel pin from TcGcn-l I bMurr M 25 ( Portim of specimen epltlaquoeraquol ilt fuel sill ii on l l location A-4laquo) lotjlion A-5 ltr) loolion A- i ft loci lion A-16
- l i bull gt i i glaquo i^_ a ^ bdquo ^ ^
ten from (he Uttattnas lthlaquown in I ijt A fc7 jlaquod deformed lltgt tide of ejch figure fat Location -1h) location A-2raquorgt
^
I
I t - -
BLANK PAGE amp bull
^bull
raquo-raquoMlaquoraquoWr
F)B 472 Sanata tmm lyat 301 itiialf steel fad pin ham Te atfunwed lo (xtmn at 25 C Poriwtt of specimen exposed lo fuel I locatio 4A to location AAIlt) location I6A
~^raquo-raquo i i T -- T-II bullraquoMraquoraquoMr5w mi j immmtmt^m
mm - bull - - bull bull bull - bull -
BLANK PAGE
mdash t - bull bull-bullbull -r^gatMtJliHwJraquoiWrraquovraquotj^WVu^-4-tgt- ~J(W~
fiMAmimraquom0mfMraquo-mdash- --- bullmdashmdash~~^--raquo bull
128
600 iim
M type 904 minim Heel fad pin from TlaquoClaquoM-I Rings taken from the locations shown in Fig 667 and C Portion of specimen exposed to fuel salt is on the lower side of each figure ltn Location 2A Ih) (lt) location I6A
2 ^ - m TMinfc
BLANK PAGE
128
600 pm
Ac locations shown in Fraquo 667 and bullf each fifiire It) Location 1A (ft) 3 L +ot nMtmgwmm
129
rlaquoJ3 raquo T e i bull Tea
nmHtrntMiaoam location
Type Concentration of bull T e C o ~ e ~ r t - o f bull bull T e nmHtrntMiaoam location
Type
bullpm total at JpnWg gcnr at i f f bull p a i o t a l o t a p a V l an or i a f
No 1 - IncondtOI 11 111
A B
S 2 J X 1 0 4tS X 10
4 2J7X 10
poundraquoSx 10 237 x 10
4 444 X 10
IB2 IB2 IB2
A B C
lt2J x 10 159 x 19 7laquoS X 10
4 r7SX 10 114 X 10
lt2J7 x 10 bull00 X 10 744 X 10
4 113 x 10- 45 x 10
IB3 IB3 IB3
A B C
pound53 x 10 27 X 10 247 x 10
4 345 X Iff 331 X 1 0
lt l 7x 10 34 X 10 143 X 10
4 57 X 10 99 x 10
No 2 - HasteHoy N 2raquo1 211
A B
lt M ( 10 749 X 10
4 3-Mx 10bull
lt I 4 4 X 10 497 X 10
4 094 X 10
2B2 2B2 2B2
A B C
raquoj x 10 29S X 10 7t X 10
4 Ml x 10 bull 5 i x 10
lt5 4x 10 202 X 10 594 X 10
4 3-7 X 10 24 x 10
2B3 13 2B3
A B C
lt54 X 10 laquol9x 10 34SX 10
4 422 x 10 bull 249 X 10 bull
lt 5 4 x 10 bull 05 X 10 393 X 10
4 U l x 10 141 x 10-
No 3 type 30 stainless start
3BI 3BI
A B
552 X 10 131 X 10
304 X 10 072 x 10bull
959 x 10 143 X 10
IS0X 10 3-44 x 10
3B2 3B2 3B2
A B C
954 X 10 25copy x 10 900 x 10
bull29 X 10
131 x 10
30 x 10 340 x 10
1042 x 10
bull J l x W iat x io 4laquoX 10
3B3 3B3 3B3
A B C
I M x 10 127 X 10 S3S x 10
116 x Icopy 044 x 10 74 X 10 bull
542 X 10 315 x 10 323 x 10
3-3 X 10 19 X 10bull 197 X 10
A denotes 100 a n aarntwn obuiotd by leaching the metal nanjlr m mbocit (soJimdash Tersenate boric an mdash I iiiinmdash cttnlel B i 100 cm sowlion obtained by l u i l raquo n the metal amftt m raquoraquobullraquo reeja lo remore aboat I M i of nartaLC denotes 100 cm sotation obtained by distorting aboal I g of salt in Mtric icid ( I JO saturated with bone acid Counts for iniiiidojl Radioes gram in dionfegralions pei Minnie (dpntt total for chemistry types A and Band dpM per graa of salt for type C daroMBry saMpfc These cooam ace laboratory w n t u i and abject to sctta corrections omkh lane not been none cThese concentrations are espitjatd as grams of the particnlar nncMr per CM of Metal sartace for cheaaatry ample types A an B ant ar exams of nailidc per gram of alt for chemistry siMpli type C The nines hare been court nd back to the conrfcjsiBn of die H amnion Concentration flwinglit safTiciently low to be ignore
sample numbers ending with I (ie I B l 2B1 and 3BI ) designate the material that came from the fuel pin wall exposed to the gas space above the salt The ample numbers ending with 2 designate material that came from the fuel pin exposed to the fuel salt just below the sail-gas interface and the sample numbers ending with 3 designate material that came from the portion of the fuel pin exposed to fuel salt near the bottom of the capsule Solutions were prepared for analysis by leachshying metal samples of each tube in verbocit to remove residual salt (type A solution in Table 623) leaching the rings in aqua regia (type B solution in Table 623) and dissolving about I g of salt removed from the metal rings in nitric acid (type C solution in Table 623) These solutions were counted to determine the amounts of J 7 T c and T e present The direct results of
these analyses are presented in Table 623 but cannot be interpreted directly because a number of corrections have not been made The data have been corrected as well as possible o reflect the concentration of each nuclide at the end of irradiation The concentrations for the leaches from the metal specimens are expressed as grams per square centinpoundtcr of tube wall exposed to the fuel salt and the concentrations for the salt samples are expressed as grams per gram of salt
The ORIGEN code was used by Kerr and Allen to predict the concentrations of tellurium isotopes that should have been present These calculations have been used extensively in the subsequent analysis of the data Table 624 compares the quantities of 7 raquo T e and l l laquo m T e f o o n ( j m | h e ( n r e e f ^ i p j p W j ( n thoje p r e
dieted to be present by the ORIGEN calculations For
130
each fud pin the one sample taken of the tube in the gas space was assumed to be typical of that region and the two samples from the salt-cowered parts were avershyaged to obtain a typical value for the salt-covered region As shown in Table 6 2 4 generally about 20 of the T T e and 1 T e was found The percent of tellurium found in the Incond 601 capsule was apprecishyably higher due to the higher amount found on the salt-covered metal surfaces
There are several possible ex|)lanations why the conshycentrations of I 7 T e and 2 T e found are only about 20 of those produced One possibility is that the amounts calculated arc too high This appears not to be the case but the calculations wiQ be checked further The most likely explanation is that the add leach was not sufficient to remove all of the tellurium from the wall The tube segments were suspended in the acid with the made and outside surfaces of the tube wall exposed as well as the cut surfacr on each side of the ampin tube segment Based on the weight changes obshyserved and the assumption of uniform metal removal the thickness of metal removed appears to be about 08 mil Since the cracks extended deeper than 08 mil in the HasteDoy N the tellurium likely penetrated deeper than did the leaching solution However the cracks in the other two materials were very shallow and the
08-roii dissolution should have recovered a higher fracshytion of the teflurium if one can equate the depth of cracking to the depth of tellurium penetration The results in Table 6 2 4 show no evidence of a systematic variation in the percent recovered from the three tubes Several possible explanations for the apparent discrepshyancy in the quantities of teflurium generated and that actually found are being investigated but none appears reasonable at this time
The concentrations of 2 7 T e and 2Te found in the salt can be used to predict upper limits for the solubility of tellurium in fuel salt under these condishytions The I 7 Te nuclide concentration in the a l t ranges from 114 X 10 to 131 X 10 g pet gram of salt (Table 623) The ORIGEN calculations were used to estimate the ratio of l 2 T Te to total tellurium and this ratio was used to convert the above concentrations of T T e to total teflurium concentrations of 007 to 083 pom Smiariy the concentration of 2 T e ranged from 45 X 10 to 648 X 10~ g per gram of salt and these correspond to total teluriurn concentrashytions of OJOS to 113 ppm The low values in both cases were noted in the Inconel 601 pin and the higher values were observed in the type 304 stamhts steel pin The concentrations m the HasteSoy N pin were only slightly less than noted for the type 304 stainless steel pin The
TaMt624 A w o mdash l o f T CnhnsM bull n r i o t i kKSfuOtv ol fed pint tmm TcGea-I (a)
IncondoOl HastdloyN Type 304
mje bull T bull gtraquorT e T e mje bull T bull gtraquorT e T e bull T e bull T e
Salt 41 x 10 bull 13 x 10 - 10 x 10- 35 x 10 M X 10 74 x 10 Metal-vapor space 14 x 10 24 x 0 21 X 10 50 x 10 2Jgt X 10 i2 x ie- Metal-sll covet at 17 x 10 23 x I t r 78 x 1 0 25 x 1 3 44 X iW 39 x 10 T
Total fomd 19 X ltgt-bull 27 x IC II x 10-bull 3 5 x 10 laquo 2 x 10 23 X 10 Total formed 3 A 2 x 10 bull 134 x I 0 f 40 x 10 148 x 10 36 X 1 0 134 x 10 laquo ferccM found $2 20 2raquo 23 23 17
of frnl MM hum TlaquoGcn-l (10 aon)
Location Incoiwi bull 1 HastcftorN Type 304
is sled Location bull T e raquo T laquo T e bull T e
Type
bull T e raquo T laquo T e bull T e T e T
Mctal-vapor space Bl MetaMaii location B2 Metal-salt locaiion 83 Avenge if foul yield evenrr distributed
257 bull 75 345
112
446 113 576
413
3J6 152 422
123
94 376
IS 1 456
376 229 095
112
214 I M 103
413
131
higher chromium concentration of the Inconet 60 may have caiced the lower tellurium concentration in the fuel salt
The con-entrations of l l l m J e and t 2 9 m l e are expressed in Table 625 in terms of grams per unit surshyface area There appear to be significant variations within each capsule but there is no consistency beshytween the various pins The high value for ITe in the vapor space of the type 304 stainless steel pin is likely anomalous since the n T e t$ not i s high Thus ai this time we conclude that the tellurium is distributed uniformly over the entire surface area of the pin
616 SALT PREPARATION AND FUEL PIN FILLING FOR TeGea-2 AND -3
M R Bennett A D Kelmers
The purpose of this portion of the TeGen activity is to prepare purified MSRE-type fuel salt containing bulliiV and to then transfer a known quantity of this salt into fuel pins gtr subsequent irradiation in the ORR One batch of purified salt will be prepared and used in two filling operations to fill two sets of six fuel pins each identified as TeGen-2 and TeGen-3 Similar activishyties in 1972 to fill the fuel pins used in experiment TeGen-I have been previously described2 3 To MSRE-
type fuei carrier salt containing LiF-BeF-ZrF4
(647-301-52 moleltv)sufficient U O j and 2 U F 4
were added to produce a fmji composition of LiF-BeF -Z r F 4 - I 3 3 U F 4 - 2 U F 4 63J08-29J5-5 O7-1 0O-15O mole ) after hydefluorination to reduce the oxide content The uranium will be reduced by hydrogen or bv beryllium if necessary to a U3 content of 10 to 18 and a measured xlume of salt will be transferred into the fuel pins The design permits obtaining a preshydetermined volume in the pins by flushing through an excess salt volume and then blowing back the salt in the upper portion of the pins to leave a predetermined volshyume
The equipment in Building 4508 used previously for this work was reactivated and modified where approprishyate A safety summary and step-by-step operating proceshydure have been prepared and approved During the latshyter part of this i port period the salt components were charged to the salt purification vessel and a 364ir hydrofluorination at 600degC was completed Both filshytered and unfiltered samples were obtained after hydroshyfluorination in copper filter sticks After analytical results indicating satisfactory removal of oxide liave been received hydrogen reduction of about 1 of the UF 4 will be carried out
23 R L Sain J H Suffer H E McCoy and P N HjabcnrcKh MSR htrprnm Srmmcvni trofr Rep Aug il 1972 ORNL-4832 pp 90 9
7 Fuel Processing Materials Development
J R DiStefano H E McCoy
The processes that are being developed for isolation of protactinium and removal of fission products from molten-salt breeder reactors require materials that are corrosion restrtint to bismuth-lithium ind inoiiev fluoshyride solutions Past experience has indicated that alshythough their solubiities in bismuth are low iron-base alloys mass transfer rapidly in bismuth at 500 to 700 SC The most promising materials for salt processing are molybdenum Ta-10^ W and graphite Molybdenum has been tested in a wide range of bismuth-lithium solushytions for up to lOjOOO hr and has shown excellent comshypatibility Thermodynamic data and literature reports indicate that molybdenum will also be compatible with molten fluoride mixtures
Ta-10 W also has excellent compatibility with bismuth-lithium solutions but tests are required to measure its compatibuity with molten fluoride salts A thermal convection loop has been constructed of Ta-10 W and a test with LiFBeF2-ThF4-UFlaquo (72-16-117-03 mole ) wffl be started during the next reporting period
Graphite has shown excellent compatibility with both bismuth-lithium solutions and molten salts Although no cheruicai interaction between bismuth-lifcisas solushytions and graphite has been found the hqtsd-KjsuS solushytion tends to penetrate the optn porosity of graphite Recent tests have evaluated the extent of penetration as a function of structure of the graphite and the Uthium concentration of the bismuth-hthium solution Dynamic tests of graphite with bomuth-tithium have thus far been limited to quartz oop tests circulating K - 0 J 0 I wt ( 0 3 at ) Li During the report period a test was
completed in which graphite samples were exposed to Bi-24 w 1 (42 at vt) Li in a molybdenum thermal convection loop for 3000 hr at 600 to 700degC
71 STATIC CAPSULE TESTS OF CRAPHTTE WITH BISMUTH AND
MSMUTH4JTHIIJMSOIIJ110NS
J R DiStefano
Samples of graphite with varying densities and pore diameters were exposed to H-017 wt (48 at ) Li and K - 3 w t (48 at ) Li in capsule tests for 3000 hr at 650degC Two of the graphites (Table 71) were pitch impregnated t j increase their densities and reduce their pore sizes1 The relatively high densities of these graphshyites indicate that impregnation was effective but the pore size distribution in the samples shows that some of the larger pores were unfilled or only partially fdkd Specimens were graphite rods 6 mm (024 in) X 381 mm (15 in) long that were threaded into an ATJ graphite holder The specimens and holder fit into a graphite capsule which contained the bismuth-lithium solution (Fig 7IK The laquoniire aoembiy was sealed in a suhwVss steel outer capsule by welding in argon Samshyples exposed to 61-017 wt (48 at ) Li showed little evidence of penetration except in low-density areas (Fig 12) Samples exposed to Bi-3 wt (48 at ) Li were penetrated more uniformly and the depth
1 Al grapfcilei were fabricated by C ft Kennedy of the Carbon and Graphite Groap Merab and Ceramics Dmnon OftNL
TaMr7l P f t trjtnPnt 01 yinpfcitt fcy lNpMvtfc4ilfcM McapfritttattlbrJtei b r a t t s r c
MISflMM
Graphite demtty Igcml
Ranee of porediam
Maximmn pore diameter chat
conrribnies 10 to total pDtoaly
ltraquogt
nuefration (mils) bulldentiOcatiow
demtty Igcml
Ranee of porediam
Maximmn pore diameter chat
conrribnies 10 to total pDtoaly
ltraquogt K 0ITOU m 3Li
334K 44-25 K 33-3SK 44-26K 44-23K
IM IM 190 ISO 159
01 1 01 2 01 2 01 35 OI 4 5
1 12 I J I J 45
0 5 0 17 8 0 5 5 0 -2 8 0 2 15
Impregnated
NonvMrform penetration in one -gtr two area only
132
133
0MlaquoL-0laquoCrS-l4M9
Flaquo 71 GapMe (bimdasheh lithww) opiate fed asmMy
of penetration increased with increasing pore size and decreasing density Results from previous tests have been inconclusive as to tnr effect of lithium concentrashytion in bismuth on penetration of graphite In the curshyrent series all graphites were penetrated tc a greater extent by K - 3 wt (48 at ) Li than by Bimdash017 wt 9f (48 at ) Li Tests of 10000 hr duration with these graphites are continuing
72 THERMAL GRADIENT MASS TRANSFER TEST OF GRAPHITE IN A MOLYBDENUM LOOP
J R DiSuiano
Although graphite has low solubility in pure bismuth (less than I ppm at 600degC) capsule lest results have shown that higher carbon concentrations are present in Bi -2 wt (38 at ) Li and K-3 wt (48 at ) Li solutions after contact with graphite To avoid the joining proolems associated with fabrication of a graphshyite loop a molybdenum loop was constructed and interlocking tabular giaphite specimens were suspended
in the vertical hot- and cold-leg sections2 In addition to mass transfer of graphite from hot- to cold-leg areas penetration of graphite by bismuth-lithium and mass transfer between graphite and molybdenum were evalushyated
721 WcajMCkaafes
The loop (CPML4) circulated K-24 wt (4 at 3 ) Li for 3000 hr at 700degC (approximately) maximum temperature and 600degC minimum temperature Weight changes in the graphite samples are given in Tables 72 and 7 J After the bismuth-lithium solution was drained from the loop the samples were removed and weighed (after-test column in Tables 12 and 7 3 ) Subshysequently they were clltmdashned at room temperature in ethyi alcohol and in an hO-HNOj (100 ml H 2 O-30 ml 90 HNOj) solution to remove bismuth-lithium adhering to the surfaces of some samples Samples from the cold leg were weighed and then kept in air for two days prior to the alcohol treatment After soaking in alcohol these samples showed larger weight gains than the after-test weight gains and this is attributed to reacshytion of lithium in the sample with moisture in the air during the two-day period AD samples showed large weight gains (33-67) and gains in hot-leg samples were on the average larger than those in the cold-leg samples
122 Compositional Changes
Graphite samples were analyzed before and after treatment with H 2 0 - H N 0 3 and the results are shown in Table 74 These results indicate that bismuth was primarily responsible for the large weight increases and that samples picked up molybdenum but treating them with H 2 0-HNOj completely removed the molybshydenum An electron-beam microprobe analysis of a graphite sample before acid cleaning showed that molybdenum was present on the outer surface of the specimen (Fig 13) Chemical analyses of other graphite samples after acid cleaning are shown in Table 75
Analysts of bismuth-lithium samples from the loop are shown in Table 76 For sampling the hot leg was sectioned so that one sample came from the surface that was in contact with the molybdenum tube wall while the other sample was taken from the interior of the section away from the wall The concentration of carbon in the melt was highest in the sample from the hot leg and both molybdenum ami carbon concentra-
2 i R DiStefano MSR Program Semimnu frofr Rep Pth 28 1975 ORNL-5047pp 140 41
li-3 11 V-IMIOi
-I5H raquobull Mplaquolaquom
F| ) NtMlnltpnorpirMttuiriMwManorMnKluHurinfMltiiid Itlhlum InMwiulli tuniliiiltgtnraquo IIHNI hr M fcjnV
13S
r7J iraquoATJ bull CML4
Wclaquofci If) Welaquofci bullKVU9 I
n mdash t r i bullefore Mi l
After m i
After
bull U k n t w l
After
raquoH04mo
Welaquofci bullKVU9 I bullefore
Mi l After m i
After
bull U k n t w l
After
raquoH04mo ltlaquo) laquoltgt
5 0 4 5 3 0S244 0 1 2 2 0704 02443 54 7 05220 0970 0 95 0S29S 0 3071 59 04494 09551 0933 0X298 OJ304 6
| l gt 0 400 0959 0919 07944 03144 I I 0432 0 3 3 9 0S3O3 07102 0277 4 12 0 4 5 09302 0923 079 03075 7 13 04753 0979 0974 0 7 02933 2 1 0432 09175 09152 075 0302 5 17 04742 09099 0905S 0794 02952 62 IS CS070 09005 0 J 9 5 07975 0290S 57 1 04709 0-raquollaquo9 0142 0 7 1 02459 52 zo 0539 091 M 09149 0 107 0 J 7 J 51 21 0513 OK52 0 J 2 9 072 02453 4 22 0 5 I M 0 M99 0 M59 0759 0J407 4 23 0-539 09103 090 07475 02067 3 24 03405 0 5 4 5 0 4 9 7 07235 01130 33
Top of IKM ley I
Kwlion of hoi leg M laquo | I J M I
rare 0 700C Q0-2OC
Vclaquofti it)
Wclaquoht After Wclaquoht
n m b r t Before After stjfldiHC in am tot two day
After
H 0 -HNO
mcreaK n m b r t
lev lejl
stjfldiHC in am tot two day
After
H 0 -HNO ltIgt I
makohol
27 04 4 0749 0722 0 4 0 01794 39 2 0421 0 2 4 OS4I2 0 2 0 01439 30 29 04717 07793 07913 06433 0 I 7 - 36 30 0477 0713 07239 0291 0151$ 32 31 044 07209 07315 0 3 9 a i 5 4 8 32 32 0427 0729 07744 0647 01 raquo20 3 33 047ft 07193 07 TOO 0331 01543 32 34 0470 0756 0772 0653 012 39 35 0424 073raquo2 0745 0 2 9 0 016 3 3 0423 0749 0759 0343 01520 32 37 0447 07331 07432 0 239 01572 34 3S 04713 07513 0719 0641 01705 3 39 04745 0749 070 0 506 0171 37 40 042 0725 07390 0233 01605 35 41 04725 0745laquo 07J53 0 419 01694 3 42 04100 07427 07525 0652 01726 36 4 3 0476 0720 07401 0647 01712 3
Top of onM leg lempmlvrc 60 60 C ftotlom of cold ley temperalarc 620 630C
136
aMr 74 n a m e d bull bull bull bull bull bull bull ttVli
S jmr t rm HRJIWT Coadiiion Cuacramnunlraquo i
S jmr t rm HRJIWT Coadiiion 3i Li gt
4 (hH WTraquo 4 tbraquort llaquogt
i Ui4d iclt
l a t k a a r d Acid cftcaAGd (bullctnacd Atid ckaacd
4 3 43 40
bull gt 0J I 04
bull11 ltlaquolOI
bullMM ltlaquoMU
tions were higher than were found previously in quart loop tests circuiting Bi-OjOl wt (03 n bulllt Li Quartz loop test 11 contained molybdenum samples and analysis of the bismuth-Uthium solution after test shewed that t contained 25 ppm molybdenum Quartz loop 8 contained samples of three different grades of graphite and the bismuth-tiimum solution contained 10 to 15 ppm carbon after the test
J O B Caiwt j ad L ft Trotter MSR i Awfr Rep Air _ 1971 OKSL-4 p i - 3
V1330SS
BACKSCATTERED ELECTRONS
- - - Oraquo J
V
8 i M a X-RAYS Me L X-RAYS
Ffcgt 7J EMCWIM kmn) laquoeaaninj M H J M r laquoapnlaquo taawnf to Mnmrth Vnw IA) a backmttcrcd electron picture of sample tarface dark material n tnpfcitc and bright material is bianulh and malybdemHM as indicated by iff)and O
117
Tank 7 3 C k a m anakwaaf p i j i i i r bull bull | l i r f c mdash C F M L - 4
bull bullbe U Mo
1 Hot kg 37 0J5 ltOJraquol ltraquo H o i k s 42 044 lt0OI
15 H o i k 4 04 ltO01 l raquo Hocks 3 0 J 5 lt 0 0 1 24 Hotks 2i 025 ltOOI ^ T C o M k f J 0 3 5 ltO0 I 31 C o M k f 21 0 2 5 lt00I 3 C o M k f I t 02 ltoot 42 CoMkc 23 02 lt0Jraquo
Sampio plusmni deaneu m H OMNO prior to a i r
Tabk7 A ^ s t t t a M M i
CoaceaiDiMt
Sample location C ippa l
Mo tppau
Li fit
Hot k f icowl Kof kg iflwfaotf r
CoM kg loner
43 10 24
17 102
4
23 3 0 1
On a raghl bam Interior tampk
Surface simple in contact raquonb molyb i fcmdash rabe laquoaH
Selected graphite samples from hot- and cold-leg regions are shown in fig 74 The white phase distribshyuted throughout the samples is bismuth these samples were add cleaned and it is evident that bismuth was dissolved from the area near the surface Molybdenum samples from hot- and cold-leg regions are shown in Fig 75 Surface layers measuring 0015 to OJ025 mm (0 6 -1 mil) thick were found on the hot-kg sample In some areas ttwie was a single layer while a double layer was found in other areas Electron-beam mkroprobe analysis indicated the single layer andor outer layer to be primarily molybdenum This layer was much harder than the base metal (1000-1200 DPH compared with about 200 DPH) indicating that it is probably MojC Where there is a double layer the outer layer appears to be MojC but the inner byer n primarily bismuth One explanation is that the MojC layer cracked andor spailed allowing the entry of bismuth which did not drain when (he lest was terminated The molybdenum sample from the cold leg also exhibited a surface layer
i o raquo f l u C mm t h k k i gt i i 33S SSSH3 S CCSSpSKBOS to that found in the hot leg Samplrs of molybdenum from hot and cold legs have been submitted for chemishycal analysis
The prindtMl objective of this experiment was toeval-uate temperaiure-gtadieai mass transfer of graphite in bismuth umijiuiug a retainer high concentration of lithium However mass transfer data were obscured by the gross pickup of bismuth by the graphite samples Previous capsule and quartz loop tests with ATJ graphshyite had indicated much less intrusion of the graphite by bismuth than occurred in the molybdenum loop test This suggests that the permeabihty at ATJ graphite to bisnush-hdnum does not depend simply on the po-rc^y of the graphite It is generally accepted that some fracioa of the pores in graphite is effectively sealed off 7uraquo contributes nothmg to flow Therefore the conshynected pore system controls the penneabraty The shape of the connected pores influences the type of flow and die length of the path the fluid takes through the sample For a nonwettiug liquid the external presshysure forcing the liquid into the pores 1 must overshycome the surface tension of the liquid This defines a critical pore radius r( and unt l the pressure exceeds the value given by
lrraquo=27costfr c ltgt
where y is the surface tension and 9 the wetting angle the pore cannot support flow Thus for a given - I f rc is the minimum pore size that w H be penetrated In both the metal and quartz thermal convectica loops IT is determined by the argon overpressure ( lt l atm) and the height of btsmmh-fcthium solution above the sample and these wne essentially the same in both types of tests Temperature affects both a and 9 but all o( the tests were operated under similar thne-temperature-^r conditions Graphite samples used hi the quartz too tests had almost four limes the surface area o f the tabushylar specimens used in the current test but they were almost three times as thick The larger surface area of the quartz loop specimens should have increased the relative amount of bismuth-lithium intrusion but the greater thickness of these samples would reduce the pershycentage increase ATJ graphite samples from the quartz loop tests increased in weight by 01 to 06 wt ar far less than the 30 to 67 wt increases noted hi samples from the current loop test Thus specimen geometry alone does not seem to explain the differences noted However the surface tension o and wetting angle 9 were
138
3
i 8
a
139
Y-I33405
- n r fimfir nriiiTii ifiari Bottom of Hot Leg 600C Bottom of Cold Log 620C
f 75 MolyMniBin tube waN from thermal comectkm loop CPML-4 thai cin slated Bi-24raquo Li and contahnd graphite ^CCMCHS
probably different because the lithium concentrations of the bismuth-lithium solutions were different and molybdenum was present in the current test It is posshysible that the presence of molybdenum on tie surface of the graphite had a marked effect on the contact angle 0 fn an earlier series of tests the bismuth content of graphite specimens was much higher when they were tested in molybdenum capsules instead of graphite capshy
sules4 Accordingly data on the wetting of graphite by-bismuth containing lithium and other constituents of processing solutions would be useful for predicting the resistance of graphite to penetration
4 J R PiStefano and O B CavmMSR Profnm Semumnu Pmgr Rep Feb 2K 1975 ORNL-SM7 pp 137 39
Pan 4 Fuel Processing for Molten-Salt Reactors
J R HightowerJr
The activities described in this section deal with the development of processes for the isolation of protacshytinium and for the removal of fission products from molten-salt breeder reactors Continuous removal of these materials is necessary for molten-salt reactors to operate as high-performance breeders During this report period engineering development progressed on continuous fluorinators for uranium removal the metal transfer process for rare-earth removal the fuel recon-stitution step and molten salt-bismuth contactors to be used in reductive extraction processes Work on chemistry of fluorination and fuel reconstitution was deferred to provide experienced personnel for the prepshyaration of salt for the TeGen-2 and -3 experiments (Sect 617)
The metal transfer experiment MTE-3B was started In this experiment all parts of the metal transfer process for rare-earth removal are demonstrated using salt flow rates which are about 1 of those required to process the fuel salt in a lOOO-MW(e) MSBR This experiment repeats a previous one (MTE-3) to determine the reasons for the unexpectedly low mass transfer coeffishycients seen in MTE-3 During this report period the salt and bismuth phases were transferred to the experishymental vessels and two runs with agitator speeds of 5 rps were made to measure the rate of transfer of neo-dymium from the fluoride salt to the Bi-Li stripper solushytion However in these runs the fluoride salt was enshytrained at low rates into the LiCl which resulted in depletion of the lithium from the Bi-Li solution in the stripper Fuel-salt entrainnient was unexpected since no entrainment was seeii in experiment MTE-3 under (as far as can be determined) identical conditions The Measurement of mass transfer coefficient in these first tvo runs was not compromised by the cntrainment The measured mass transfer coefficients were lower than
predicted by literature correlations but the values are comparable to those obtained from experiment MTE-3
Mechanically agitated nondispersing salt-metal conshytactors of the type used in experiment MTE-3B are of interest because entrainment of bismuth into the fuel salt can be minimized because very high ratios of bisshymuth flow rate to salt flow rate can be more easily handled than in column-type contactors and beczuse these contactors appear to be more easily fabricated from molybdenum and graphite components than are column-type contactors Attempts were made to measshyure entrainment rates of fluoride salt in bismuth and entrainment rates of bismuth in fluoride salt under conshyditions where the phases were not dispersed and under conditions where some phase dispersal was expected These measurements were made in the o-tn-diam (01 S-m) contactor installed in the Salt-Bismuth Flow-through Facility The results indicate that mild phase dispersal with in concomitant high mass transfer coeffishycients night be allowable in the reductive extraction processes We are continuing development of methods for measuring mass transfer coefficients in mercury-water systems to learn how to scale up contactors which would be used with salt and bismuth
A nonradioactive demonstration of frozen salt corshyrosion protection ir a continuous fluorinator requires a heat source that is not subject to attack by fluorine in the fluorinator To provide such a heat source for future fluorinator experiments we have continued our studies of autoresistance heating of molten salt During the report period we have completed new equipment for studying autoresistance heating of molten salt in a flow system similar to a planned continuous fluorinator exshyperiment three preliminary runs have been made with the equipment The design was started for a facility for developing continuous fluorinators and equipment is
140
141
being installed for an experiment to demonstrate the effectiveness of frozen salt for protection against fluoshyrine corrosion
The uranium removed from the fuel salt rraquogt fiuorina-tion must be returned to the processed salt in the fuel reconstitution step before the fuel salt is returned to the reactor An engineering experiment to demonstrate the fuel reconstitution step is being installed In this experishyment gold-lined equipment will be used to avoid introshyducing products of corrosion by U F and U F S Alternashytive methods for providing the gold lining include elecshytroplating and mechanical fabrication The choice beshytween the two depends on availability of gold from fcRDA precious-metal accounts and the price of gold from the open market Instrumentation for the analysis
of the vessel off-gas streams has been installed and is being calibrated
Future development of the fuel processing operations wdl require a large facility for engineering experiment A design report is being prepared to define the scope estimated design and construction costs method of accomplishment and schedules for a proposed MSBR Fuel Processing Engineering Center The building will provide space fcr preparation and purification at salt mixtures fcr engineering experimenis up 10 the scale required fcr a I0OO-MW(e) MSBR and for laboratories maintenance areas and offices The estimated cost of thrs facility is SISjOOOjQOO and authorization is proshyposed for FY 1978
R Engineering Development of Processing Operations
J R Miditower Jr
81 METAL TRANSFER PROCESS DEVELOPMENT
HC Savage
During this report period the salt and bismuth solushytions were charged to the process vessels of the metal transfer experiment MTE-3B Two experiments were completed in which the rate of removal of neodymium from molten-salt breeder reactor fuel salt (72-16-12 mole LiF-BeF 2-ThF 4) was measured
The MTE-3B process equipment (Fig 81) consisted of three interconnected vessels a 14-in-diam (036-m) fuel salt reservoir a 10-in-diam(025-m)salt-metal conshytactor and a 6-in-diam (015-m) rare-earth stripper The salt-metal contactor is divided into two compartshyments interconnected through two 05-in-high lt 13-mm)
I H C Savage Bngmeenng Development Studies for Molten-Sat Breeder Reactor Processing Xo -0 ORNL-TSM870 (in preparation)
by 3-in-wide (76-mm) slots in the bottom of the divider Bismuth containing thorium and lithium is cirshyculated through the dots Thus fluoride fuel salt was in contact with the Bi-Th in one compartment and LiG was in contact with the Bi-Th in the other compartshyment The stripper contains lithium-bismuth solution (5-95 at ) in contact with the LiCl Mechanical agitashytors having separate blades in each phase in the conshytactor and stripper were used to promote mass transfer across the three salt-metal interfaces The fluoride fuel salt was circulated between the reservoir and contactor by means of a gas-operated pump with bismuth check valves The LrCl was circulated between the stripper and contactor by alternately pressurizing and venting the stripper vessel
The bismuth-thorium phase was circulated between the two compartments of the contactor by the action of the agitators and no direct measurement of this flow rate was made during the experiment however measshyurements made in a mockup using a mercury-water system indicated that the Bi-Th circulation rate between
ORWL-06-71 1471
AWTATORS-
LEVEL ELECTRODES
LiT-raquoF--TMU Li-a
FLUORIDE SALT
RESERVOIR
SALT- KCTAL CONTACTOR
M M EARTH STRIPPER
F 81 Flow diagram for metal trmrfcr experiment MTC-3
142
143
the two compartments should be high enough to keep the concentration of rare earths in both compartments essentially the same2 This was found to be the case in the two experiments in MTE-3B
In this experiment neodymium is extracted from the fuel carrier salt into the thorium-bismuth solution Next the neodymivm is extracted from the thorium-bismuth into molten LiCI and finally (he neodymium is stripped from the LiCI into bismuth-lithium alloy
Operating variables in the experiment are
1 the flow rate of the fluoride fuel salt between the fuel salt reservoir and the contactor
2 the flow rate of the lithium chloride salt between the contactor and the stripper vessel
3 the degree of agitation of the salt and bismuth pluses in the contactor and stripper
4 the amount of reductant (lithium) in the bismuth phase in the contactor
The operating temperature of the systen is ^-650degC Overall mass transfer rates for representative rare-earth fission products are determined by adding the rare earth to the fluoride fuel salt in the reservoir and observing the rate of transfer of the rare earth across the three salt-bismuth interfaces as a function of time by periodic sampling of all phases
2 H O Weeren and L E McNcese Engineering Developshyment Studies far Molten-Sail Breeder Reactor Processing So 10 ORNL-TM-3352 (September 1974) pp 57 59
[taring the course cf the experiments the concentrashytions of neodymium in each phase were deteiiaiacd by counting the 053-MeV gamma radiation emitted bv 4 T N d tracer added to the neodymium origmaBy in the fuel salt This provided a rapid method for fallowing the transfer rate More accurate data necessary for calculatshying the overal mass transfer coeffiaeats at each of the three salt-metal interfaces were obtained by analyzing samples of the salt aM bismum phases for total teo-dymium via an isotonic dilution mass spectrometry technique Use of this technique avows measurement of neodymium concentrations as low as OJOI ppm (wt)
811 of Salt J to Metal MTF3
The quantities ot salts and bismuth charged to the process vessels of experiment MTE-3B are listed in Table 81 AD internal surfaces of the carbon-steel vesshysels were hydrogen treated at 650degC for V7 hr to reshymove any oxides prior to the addition of the salt and bismuth solutions The auxiliary charging vessels used in the additions were also hydrogen treated Subsequently a purified argon atmosphere was maintained in all the vessels to prevent oxide contamination (via ingress of air or moisture) of the vessels and process solutions
The charging vessels were IO-in-diam (0_25-m) carboa-steH vessels o f about 22 liters (0022 m 3 ) in volume equipped with electric heaters for melting the salts and bismuth Nozzles and access ports were pro-
Tabie8l Qwtit iet ot salts and tnsmmtk for o u M i w f t MTE-3B
Material Vessel Volume at
650C (liters)
Wesgh (kg) f-moles
Fluoride fuel salt Reservoir 294 970 5lt (72-16-12 mole LiF-BcF -ThF)
Fluoride fuel salt Contactor 31 102 161 (72-16-12 mole LiF-BeF-ThF)
Bismuth-thorium | M 500 ppm (wt) Th Fluoride salt 29 276 132 MO ppm Li| side of contactor
Bismuth-thorium [M500 ppm (wl)Th LiCI side of 35 33 161 M 0 ppm Li| contactor
Lithium chloride Contactor 29 43 101
Lithium chloride Stripper 38 56 132
Bismuih 5 at lithium in Stripper 43 418 200 stripper
Demiliev at 650C fluoride fuel salt 330 gcc LiCI = 1 AS gcc Bi 96 gcc Mole weight = 632 g
144
video for the addition of the salts and bismuth argon and hydrogen purge gas ones and hues required to transfer the salt and bismuth phases into the process vessels
Bismuth hydrogen treated in the charging vessel to remove oxides was the first material to be added to the contactor The fluoride fuel salt was then contacted in the charging vessel (using argon sparging) with a bismclaquoi-OIS wt thorium solution (50 of Th satushyration) for several days prior to transfer into the fuel-salt reservoir and the fluoride salt compartment of the contactor Thorium metal (01197 kg) was then added to the 614 kg of bismuth in the contactor This quanshytity of dtorium is about 50 of the amount that would be soluble and was calculated to produce a lithium conshycentration ot ^-40 ppm (wt) in the thorium-bismuth phase in the contactor based on previously reported data1 on the distribution of thorium and lithium beshytween molten bismuth and fluoride fuel -alt
FoBowing the additions of bismuth to the contactor and the fluoride fuel salt (72-16-12 mole LiF-BeF2-ThF 4) to the contactor and fuel-salt reservoir a new charging vessel was installed for makeup and charging of the bismuth-5 at lithium to the stripper and the LiCI to the contactor and stripper First bismuth was added to the charging vessel and was hydrogen treated to remove oxides by sparging with hydrogen at v-oOOC (873degK) for laquoraquo7 hr The charging vessel contained 6787 kg of bismuth to which was added 0120 kg of lithium metal to produce the bismuth-5 at lithium for the stripper Part of the bismuth-5 at lithium solution (41 amp kg) was then transferred into the stripper vessel
Thorium metal (0109 kg) was added to the 26 kg of bismuth-lithium solution remaining in the charge vessel and 1588 kg of LiCI that had been oven dried at 200degC (473degK) was added to the charge vessel The bismuth-lithium-thorium and LiCI phases were sparged with argon using a gas-lift sparge tube for four days The LiCI was then transferred into the LiG side of the conshytactor and the stripper vessel
The salt and bismuth solutions were filtered through molybdenum filters [^30 u (30 X I0~ 5 m) in pore diameter] installed in the transfer lines during transfer
- from t^e charging vessels into the MTE-3B process vessels
812 Run Nd-I
For the first run in MTE-3B 3300 mg of NdF (2360 mg of Nd) was added to the 97 kg of fluoride fuel salt (72-16-12 mole LiF-BeF2-ThF4) in the fuel salt resershyvoir on June 6 1975 The neodymium contained 722 mCi of TNd tracer (tVi - 11 days) at the time of
addition The neodymium concentration in the fuel salt in the reservoir was calculated to be 24 ppm (wt) which approximates that expected in the fuel salt of a single-region lOOO-MWie) MSBR Neodymium was chosen as the representative rare-earth fission product for the first series uf experiments in MTE-3B for several reasons
1 results could be compared with those obtained using neodyrahnn in the previous experiment4 MTE-3
2 Sd tracer used for following the rate of transfer of neodymiuni has a relatively short half-life (11 days) which would prevent excessive levels of radioshyactivity in the experimental equipment as additional neodymium containing 4 7 N d was added to the fuel salt during the expert-went
3 neodymium is one of the more important trivaknt rare-earth fission products to be removed from MSBR fuel salt
An attempt was made to start the first run (Nd-I )on June 91975 However a malfunction in the electronics of the speed control unit for the stripper-vessel agitator prevented startup After this unit was repaired run Nd-1 was started on June 15 1975 and the scheduled period of operation (100 hr) was completed on June 20 1975 Operating conditions of run Nd-I were 650 to 660CC (923 to 933degK) 5 rps agitator speeds in both contactor and stripper fluoride salt flow rate of 35 ccmin (58 X I 0 1 m 3sec) and LiCI flow rate of 12 litersmin (20 X IO 5 nrsec)
After 100 hr of fluoride salt and LiG salt circulation the fluoride salt circulation was stopped and the run was continued for 16 hr This was done to observe the expected large decrease in the concentration of neoshydymium in the smaller amount of fluoride salt in the contactor (102 kg) as compared with the 1072 kg contained in both the contactor and reservoir These data would provide a more accurate measure of the rate of transfer of neodymium across the fluoride salt-bismuth-thorium interface
Finally the circulation of LiG was also stopped The agitators in the contactor and stripper vessels were then operated for ^24 hr over a three-day period (8 hr each day) to allow the salt and bismuth phases to equilibrate in an attempt to determine neodymium distribution coefficients between the phases
3 L M Ferris Equilibrium Distribution of Actinide and Lanthanide Elements Between Molten Fluoride Salts and Liquid Bismuth Solutions Inorg Nucl Chem 32 2019 35 (1970)
4 Cfiem Ttchnol Dir Annu Prop Rep March 31 1973 ORNL-4883p 25
145
The experimental equipment operated safisfacturBy throaghout ran Nd- I AH operatiag variables were maia-taiaed at desired coaonioas Results obtained during run Nd-I are discussed in Sect 814
SI J Ran Nd-2
Run Nd-2 was done with the sam operating condishytions as ran Nd-I except for run deration (119 hr inshystead of 100 hrraquo Prior to run Nd-2 3590 mg of N d F
(250 tog of Ndgt coalaaaag 101 mCi of 4 7 N d tracer was added to the 97 kg of fad salt in the reservoir Including the ncodVaaum leinainaig in the furl salt at the end of ran Nd- I estimated to be 18 ppra ltwt) the neodymium concentration in the fuel salt in the resershyvoir at the start o f run Nd-2 is estimated to be 45 pom The neodynaum concentration in dte fuel salt in the contactor is estimated to be 9 ppm at the start of run Nd-2 We are uncertain of the amounts of neodymium in the other phases at the beginning of run Nd-2 as discussed in Sect 814
Run Nd-2 was started on July 13 1975 and was tershyminated on July 19 1975 after 139 hr of operation During the first 50 hr of operation the rate of transfer of neodymium into the lithium-bismuth phase in the stripper appeared to be about the same as observed during run Nd-I based en counting of the | 4 7 N d tracer in samples taken at regular intervals After about 60 hr of operation the transfer of neodymium into the bismuth-lithium phase in the stripper suddenly stopped and it was observed that neodymium was being exshytracted from the bismuth-lithium phase in the stripper into the LiCl in the stripper and contactor During the run a significant decrease in the emf between the stripshyper vessel and the contactor occurred (from ^160 mV to ^25 mV over a 30-hr period) indicating loss of lithshyium reductant from the bismuth-lithium phase The run was terminated after 139 hr of operation when it beshycame clear that useful information could no longer be obtained and it appeared that fluoride salt was being entrained into the LiCl in the contactor
814 Discussion of Results
Subsequent investigation and results of chemical analshyyses of samples of the salt and bismuth phases indicate that fluoride fuel salt was being entrained into the LiCl in the contactor throughout both runs Nd-I and Nd-2 Estimates of the amount entrained are shown below
Estimated amount of fluoride a l l transferred into LiCl Baas of estimate
Nd-I | I 0 laquo hr) Nd-I and -2 (Jul hr)
0292 kg Fluoride in IiO phase 0607 kg Thorium in B I - L I phase 0400 kg Increase in LKI level in
stripper
Based j a flaoriae analyses of 1X1 maple T taken daring nm Nd- I the enuaaaaeat of flaoride salt appears to have occurred at a relatively constant rate throaghoat the ran The total amount of neodyaaam which transshyferrer into the Li-K phase in the stripper daring ran Nd-I is estimated to be 300 mg The aaaoaat of aeo-dynaam contained in the entraiaed fad salt isestiuated to be 6 mg That most of the neodynaam which transshyferred into the Li-Hi in the stripper vessd was by mass transfer rather than as a result of eatiaauaeM
The reason for the ubstivtd enfaauaeat is not dear at present One explanation K that the 50-rps agitator speed is saffident to cause enirainment (entrainmeat of flaoride salt into the chloride salt occurred in the preshyvious experiment MTE-3 at 67 rps bat not at 5JO rps) Experiments are in piogiess for deternaaing whether this explanation is correct and results to date indicate that entranirmi does not occur at 3 3 rps Further experiments in MTE-3B w i l depend on determining the reason for the unexpected entrainment of fluoride nt into the LiCl- However it appears feasible to continue rare-earth mass transfer experiments in MTE-3B by removing the LiCI (contaminated with fluoride salt) and the Li-Bi solution from the stripper vessd after which purified LiCl and Li-Bi solution will be added to the system
The main nurpose of the metal transfer experiment is to measure mass transfer coefficients for the rare eanhs at the various salt-metal interfaces in the system and to determine whether a literature corrdation5 (based on studies with aqueous-organic systems) which relates many transfer coefficients to the agitator speed and other physical properties of the system is applicable to molten salt bismuth systems Data obtained from run Nd-I have been analyzed and estimates have been made of overall mass transfer coefficients for neodymium at the three salt-metal interfaces Even though entrainment of fluoride salt into LiO occurred during run Nd- I it is believed that the mass transfer rate for neodymium was not 5ignificantly affected The concentration of fluoride in the LiCl at the end of run Nd-I was vl_ wt 1 or 003 mole fraction Based on previous studies6 the disshytribution coefficient ) for neodymium between the molten bismuth-thorium solution and LiCl (mole fracshytion Nd in bismuthmole fraction Nd in LiCl) would be decreased by ^ 2 0 7 while the distribution coefficient for thorium would be decreased by a factor of ^150 This would result in a decrease in the separation factor
5 J B l-ewii Chan En Sri 3 24S 59 119541 6 I M Ferris el raquo Distribution of Lanthamde and
Actinide Klements Between Liquid Bismuth and Molten IKI-Iil- and liBr-lil Solutions Inorg ucl Chart 34 313 20(1972)
146
were t in
VIO to vIO1 i transferred
bull t o the Lid The ate of leaver of neodynuua across the three
byaaslysesofi the m Two analytical i
(1) coasting of the OS34acV by the 4 N i tracer aad (2)iKgttopicduu-
spectroaaetry luaed on ccejufhag of the 4 T N d tracer a aaMeriai buuare of the t w t j i i w of gt95 obtained at the end of run Nd-1 indicated that about 11 of the niudjununa mfrinaMj added to the fuel salt icaenvar had beea transferred iato the LMI irautioa at the stripper
The counting trchaiqf is a rapid method aad pro-oa the rate of transfer wide the mas llwwcui it does ant provide the
required for calculation of the overal mas transfer coefficients particalariy in the K-Th aad Lid
bull the contactor aad stripper vessels in which the less than 1 ppm
(wt) The isotonic ddutioa analysis is capable of accushyrately determining neodynmm conccntntioa down to -VOJOI ppmfwt) and resorts obtained from the isotopic duvtioo tednaque for the Bs-Th and LiCI phases were used for calculations of the overall mass transfer coeffishycients
Values for distribution coefficients for neodymium at the thru salt-metal internees were measured at the end of run Nd-1 for comparison with those calculated from the dau of Ferris3 bull (Table 82) The experimental values are in reasonable agreement with the calculated values in the absence of fluoride contamination indicashy
ting that the distrnVstsoa coefficieau for neodynnum were not seriously affected by the entKnuncnt of the fluorine sah into the chloride
Data obtained during run Nd-1 were analyzed by inuahawiiui solution of seven tune-dependent differenshytial mm rial twlanu equations (Fig 8 J ) that relate the
v i imdash F t laquo r V
raquo i W W F a laquos-X4gt
V j j l laquo bull Klaquoa (X-IVCraquo)-F(Xs-)^
V - MOLAR VOLUME OF EACH PHASE
F bull FLOW RATE MOLESSEC
7 L M Perm et d Distribution of Lanthannte and Actiniae Element Between Molten Uthium Halide Salts and Liquid Msmuth Solutions Inorg Piuci Oirm 342921 -33 lt1972)
OLOLDc RARE-EARTH DISTRIBUTION COEFFICIENTS MOLESMOLE
A AREA AT EACH INTERFACE CM
TaMrSJ Dutrwatioa coeffionrta for mod m msit iauat MTE-3B ran Nd-1
Salt-metal interface Calculated Experimental
Fluoride salt-Bi-Th LaO-Bi-Th LiQ-Li-Bi
0006 094
3-5 X 10
0013 064
gt I X I0raquo
Distribution coefficient laquo (mf Nd in bismuth)(mf Nd in salt) ^Conditions 6S0C (923degK) Li concentration in Bi-Th 40 ppm Li concentration in Li-Bi = 5 at no fluoride in LiG phase
K I KbdquoK gt RARE- EARTH OVERALL MASS TRANSFER COEFFICIENT CMSEC
X gt RARE- EARTH CONCENTRATION IN EACH PHASE MOLESCM
EQUATIONS USEO TO CALCULATE MASS TRANSFER COEFFICIENTS FOR METAL TRANSFER EXPERIMENT
MTE-3B
F raquo S X Equations awd to calculate maw traaafer coeffishycients for the metal Mifer p r a m experiment V volume of each phase x - rare-earth concentration l = lime A - mass transfer area F raquo flow rate D bull rare-earth distribution coeffishycient K = overall mass transfer coefficient
147
rate at which the rare earths r ~ transferred through the several stages to the distribution coefficients of the tare earth the mass flow rates and the mass transfer coeffishycients at each salt-metal interface The set of equations was solved using a computer program by selecting values for the mass transfer coefficients which resulted in the best agreement between the experimental data on rate of change of neodymium concentration in aB phases in the system and the calculated values Several trial-and-error iterations were required using adjusted values of mus transfer coefficients until a best-fit solution was obtained
The final calculated results for run Nd-1 are shown in Table 83 where the values for the overall mass tkjnsfer coefficients are given and are compared with values calshyculated by the correlation of Lewis5 The coefficients are lower than predicted and are similar to results obtained in the previous experiment MTE-34 Final analytical results for run Nd-2 are not yet available However for the first SO hr of operation the rate of accumulation of neodymium in the Li-Bi solution in the stripper appeared to be similar to that observed in run Nd-1 The significance of these absolute values of mass transfer coefficient cannot be assessed until the scaling laws in this type of contactor are known
8 L E McNeeje Engineering Development Studies )or Molten-Salt Breeder Reactor Processing o II ORNL-TM-3774 (in preparation)
8 2 SALT-MSMUTH CONTACTOR DEVELOTMENT
CH Brown Jr
Mechanically agitated nondispening salt-bismuth conshytactors are being considered for the protactinium removal step and the rare-earth removal step in the reference MSBR processing plant flowsheet These conshytactors have several advantages over packed-column salt-bismuth contactors
1 they can be operated under conditions that minimize entrainment of bismuth to the fuel salt returning to the reactor
2 they can be fabricated more economically from graphite and molybdenum components
3 they can handle more easily large flow-rate ratios of tismuth and molten salt
Experimental development of stirred interface contacshytors is being carried out in two different systems a facility in which molten fluoride salt is contacted with bismuth containing a dissolved reductant and a system in which mercury and an aqueous electrolyte phase are used to simulate bismuth and molten salt These two systems and the development work performed during this report period are described in Sects 821 and 822
Table 8J Oven mass transfer coeffkieM for iteodymmm m metal master experiment MTE-3B ran Nd-1
A (mmsec) A (mmsec) A (mmjecr
Measured1 Predicted value value ltlt)
Measured Predicted value value Cr)
Mease bdquod c Predicted value value i^)
00035 39 025 20 013 25
Based on the neodymium in the salt phase 1 I I
bmdash~ - mdash mdashmdashmdash at fluoride salt -Bi -Th interface
I D B
I l
at LiCl-Bi-Th interface
a LiO - Li-6i interface A j km k9Ds
= individual mass transfer coefficient fluoride sail to bismuth - individual man transfer coefftcien bismuth to Tuoride sail = individual man transfer coefficient bismuth In lithium chloride k - individual mass transfer coefficient lithium chloride to bismuth
where
DA - distribution coefficient between fluoride salt and bismuth Dg - distribution coefficient between chloride salt and bismuth Oc distribution coefficient between chloride salt and lithium-bismuth
cAgitator speed is 50 rps
MS
S 2 I Expernieafe win a fecsnmkaly Agitated Nnaaraquoprning Contactnr bull the Salt bull f a i t h
Flolaquortuumgt FariSty
Operation of a facility has continued in which mass transfer rates are being measured between molten LiF-BeF 2 ThF 4 (72-16-12 mok )and molten bismuth m a mechanically agitated nondispeising contactor The equipment consists of a graphite-lined stainless steel vessel salt and bismuth feed and receiver vessels and the contactor vessel h the first of these the salt and bismuth phases are stored between runs The other vessels allow for treatment of the phases with HF and H The comactor consists of a 6-ltn-diain carbon-steel vessel conta rang four I-in -wide vertical baffles The agitator consists of two 3-in-dhm stirrers having four noncanted blades A ^-in-dtam overflow at the intershyface allows removal of interfacial films i f present with the salt and metal effluent streams During a run the salt and bismuth phases are fed to the contactor by conshytrolled pressurization of the respective feed tanks the phases return to the receiver vessels by gravity flow A detailed description of the facility and operating proshycedures has been previously reported A total of nine mass transfer runs have been completed to date along with one hydrodynamic run intended to determine the amount of entrainment of one phase into the other at a sties of different agitator vxeds Results from the nine mass transfer runs have been previously reported ~ i
The experimental proceduie for and results obtained from the hydrodynamic run and treat men of the salt and bismuth with HF and H 2 are discussed in the reshymainder of this section
Experimental operation daring the hydrodynamic ran The hydrodynamic run was performed with salt and bismuth flow rates of M 5 0 and M 4 Q ccmin respectively The agitator was operated at three difshyferent speeds during the run 250310 and 386 rpm At 250 and 310 rpm three sets of unfdtereJ salt and bisshymuth samples from the contactor effluent streams were taken at 4-min intervals Three sets of unfiltered efshyfluent samples were aiso taken with the agitator operatshying at 386 rpm but the samples were taken at 2-min intervals
To avoid contamination of the sample contents with extraneous material the sample capsules were cleaned of foreign matter by the following procedure Gross amounts of salt or bismuth were first removed with a file then the sample capsule was polished with emery cloth and finally (he capsule was washed with acetone
The sample capsules were then cut open with a tubing cutter and the contents of each sample were drilled out
and visual)- inspected for the presence of one phase in the other Ho such evidence of gross entramment was found h some of the salt samples small flecks of metal were noticed which were probably small pieces of the sample capsule produced during the dnamg operation The contests of each sample were then sent to the Ana rytical Chemistry Division for dttuiiannion of brsrmnh present in gt salt samples and berynram present in the bismuth samples h is assumed that any berynmm present in the bismuth is mdkstive of entrained fluoride salt The results of these analyses are given in Table 84 The bismuth concentration in the salt samples shows a general decrease with increasing sarrer speed widi very low values occurring at the highest stirrer speed It also seems evident that the bismuth concentration in the salt phase may have been a function of the run time since after the fourth sample the bismuth concentration reshymained at a relatively constant value of 50 plusmn11 pom which is quite different from the values reported for the first four samples which ranged from 1800 to 155 ppm
These results are significantly higher than those of LindauerJ who saw less than 10 ppm of bismuth in
9 J A Klein el al tnaraquoeerme Development Stmmes far I M l d i U t Breeder Reactor hocesnm So bull ORNL-TS-463 Italy 1975) pp 2 3S
10 C H Brown Jr Engmttii-t Development Studies for Molten Salt Breeder Reactor rYoceomf So 21 ORNL-TM-4X94 (in preparation)
11 J A Kkai tnemeermw Drreiopmenl Studies of Molten-Smll Breeder Reactor Procenmt So IS ORNL-TM-469 (September 1974) pp I 22
12 C H Brown Jr Enjmerrmt Development Studies for Hoten Salt Breeder Reactor rVncezshu Vo 20 ORNL-TM-4810 (in preparation)
13 R B LindraeT fmjmeetmf Drreiopmenl Studies of Molten Salt Breeder Reactor Proceowtt So 17 ORNl-TM-41711 (m preparation)
TaWeS4 Kwmyraquoof ^aXmmhwmmmtn
Agitator speed Bi sample Be in Bi Sail sample Bi in salt (rpm) number (ppm) number (ppm)
250 42 215 437 100 250 429 125 43 205 250 430 215 439 155 310 431 85 440 270 310 432 910 441 53 10 433 442 34
36 434 110 443 64 36 435 175 444 54 36 436 50 445 43
149
fluoride salt in comact with b i t iu fh in several different contacting devices- It is likely that sample i nniiuuni tioa is a contributing factor to the high bcrmdashrh concenshytrations measured Three possible sources of sample coataaunaboa have been reported
I timtjuunitiou by withdrawing Imdashparr through a sample port which has been in contact wkh bismuth
analytical laboratory by the use of equipment roushytinely used for bismuth analyses
3 ctrwfuttiiuTmutftoit from bull hwy^CTWffy vt^tt^f^n^i^^^^UKttf material laquohkh may be floating on the salt surface
Since no maximum peiHUSMuk rate of bismuth eMram-ment in the fuel salt going to the bism ah removal step or m the salt returning to the reactor from the fuel processing plant has been set it is difficult to assess the significance of these results However the bismuth conshycentrations in the salt do not seem to be inordatttelv high at the highest stirrer speed and it seems Bkefy that some degree o f phase dispersal might be tolerated ia order to achieve higher mass transfer rates
The beryflium concentrations in the bismuth samples at each agitator speed show both high and low values with no discernaWe dependence on agitator speed These results agree well with previously reported data1 for beryllium concentration in the bismuth phase during mass transfer runs in this system at agitator speeds of 124 180 and 244 rpm Previous experiments with water-mercury and organic-mercury systems suggest entrainineni of the light phase into the heavy phase at an agitator speed of about 170 rpm The concentration of beryllium in the bismuth phase is not significantly different from previous results observed at lower agitashytor speeds The effect of entrsined fluoride salt in the bismuth would be most detrimental in the metal transshyfer process where fluoride salt in the chloride salt phase decreases the separation factors between thorn m and the rare-earth fission products
H -HF treatment of salt and bismuth The mass transshyfer runs completed to date in he salt-bismuth contactor have all been performed under conditions where the controlling resistance to mass transfer is in the inter-facial salt film One final mass transfer run will be pershyformed in which the bismuth-film mass transfer coeffishycient is measured In preparation for this run the salt and bismuth in the graphite-lined treatment vessel were treated with HF diluted with H 2 to oxidize the reduc-tants present in the bismuth phase The procedure used was essentially that reported previously14 The salt and bismuth at -v-oOOC were sparged with 25 scfh of 30 (mole) HF for 9 hr The HF utilization decreased from
7 5 at the 1 njiiiiini of treatment to 3 5 during the final 2 hr of treatmat Analysis of the ash and bismuth phases before and after treatment with HF and H 2 inshydicated that esaeatiaty a l of the rr duct ant in the bisshymuth phase was oxidized by hydrofluormatioa The mmtmm distribution ratio decreased from 740 molts mole prior to the treatment to OJ03 molemole after the HF-Hj treatment
L U ---r--8 iiiiiT I M I I I M M I U I I - j
We have continued development of a mrrhmii dlj agitated nondispersmg two-phase contactor wing an aqueous electrolyte and mercury to srmmatf mohea salts and bismuth
As previously reported1 we have investigated the feasibility of using a pobrographk technique for measuring electrolyte-film mass transfer coefficients in this type of contactor During this report period we have
1 tested three different anode materials 2 produced cathodk polarization waves corresponding
to the reduction of F e compkxed widi excess oxalate ions at the mercury surface
3 obtained and calibrated a slow-scan controDed-potential cyclic volumeter
4 examined the quinone-hydroquinone redox couple as a possible alternate to the F e -Fe couple now being used
Modifications to experimental equipment With the exshyception of the tests made with the qrinone-hydroquinone redox couple ail tests made during this pr ied were performed with the equipment previously described5
The equipment consists of the 5 X 7 in Plexiglas conshytactor used in previous work with the water-mercury system The mercury surface in the contactor acts as the cathode in the electrochemical cell The cathode is elecshytrically connected to the rest of the circuit by a Vg-in-diam stainless steel rod electrically insulated from the electrolyte phase by a Teflon sheath The anode of the cell is suspended in the aqueous electrolyte phase and consists of a metallic sheet formed to fit the inner perimeter of the Plexigas cell The current through the cell is inferred from the voltage drop across a 01 -SI plusmn 05 10-W precision resistor The signal produced
14 B A Hannaford (l jl Engineering Development Studies for HollenStll breeder Reactor Processing No 3 ORNL-TM-3l3ltMay 1971) p 30
15 C H Brown Jr Engineerin Development Studies for Mitten-Sit Breeder Reactor Processing So 22 ORNL-IM-4041 tin preparation)
ISO
on a on the
electrode
across the i Hevlen-Fackard xjr plotter The x nbtter bull nrodnoed hy the | the mncmy and a (SCE) suspended in the electrolyte |
to studies nun on the a stow-wcan controned-pocentieJ cyclic woks
patentNttat) was obtained fan the Analytical Chemistry Dtaunu to repfacr the Hewlett-Packard dc poawaapfiy iwtiionely wcd-ThecycJCfohnnrtrTiia three electrode mstrumeut which cortroh lraquo i bttnicn the mercury vnfuir and ai reference electrode whle paahag a cnrrent between the auxamry electrode and the mercury surface Voitafes can be itianrJ between tfVw SCE aad -2 Vw SCE ataacanrateaptol Vnnh The posentiostat can carry a carrot of up to 2 5 A between the auxSnry and mtiiury electrodes
npunninli ahh Ihi tt1 fi ililiai Thr rlrriin ryte used for al the experiments performed daring this report period was nouunaPy OJOOI M Ft2 obtained from ferrous sulfate 0X10025 M Fe obtained from ferric salfate and 0 J M potassium oxalate The oxalate ions form a stable complex with both the re and Fltr2
ftriuuif mnmumnm of the Fe1 reduction cdhccdy
Three anode nMcriab have been tested copper iron ml satisfactory polarization -aaves were pro-
I with al three materials However the copper and iron reacted with the electrolyte solution This addishytional uue reaction caned poor lewudacnwwty in the
I could aho p ornery alter the properties of the To amid tins cnobkrn an anode was fabrishy
cated by poring gold on a 0J062$-m-thka sheet of nickel which was formed to fit the inner perimeter of the electrochemical eel
Shown irgt Fig 8 J is a polarogram measured with the electrolyte described above in the 5 X 7 in Plexiglas contactor mag the gold anode with phase volumes of aboat IJ8 liters each and nc agitation The cell current it plotted as a function of the mercury sarface potential vs the SCE The cnrrent racreasts from zero at zero applied potential to a relatively constant value at an applied potential of about -035 V n SCE In this region contbtvons electrolysis is taking place in the cell corresponding to reduction of FetCiO^ 1 ~ at the mershycury cathode In the region of applied potential from -0J5 V vs SCE to -0JO V vs SCE the cell current
OMM 0W6 79- U429
1 1 1 1 1 1 1 S
2 lt
bull0t-M raquo raquo
m m m f~~ 5 u J I
J ew0^45V
ffl 1 1 1 1 1 0 -OJ -02
Fugt laquo3 Catholic bullohriarmi ware for FlaquoC O)
-0 5 -04 -OS VOLTM0C raquobull SCE
-OS -07 -oa
in Ac 5 X 7 J n m l raquo
151
increases only a smal iniaswt here the current is bullanted by ttugt rate of diffusion of the Fe(CzQlaquogtjgt~ to the mercury surface where this ion is rcdnced The difshyfusion current can be related to the nam transfer coefficient through the electrolyte fifan as prcwontly
The half-waw potential is defined at the potential at which the current is equal to one-half the hunting nine Figure 8 J shows the measured half-waw potential for the ferric oxalate coaapiex The half-wane potential of -0245 V measured in the contactor agrees weD with the wine reported in the literature of -024 V vs SCE for the reduction of ferric oxalate
Under ideal conditions the diffusion current is directly proportional to the polarized electrode surface area and the bulk concentration of the hinting km To detennine that the mercury surface was actually being polarized two tests were perfonned First the anode surface area was decreased by about 48 This had no effect on the magnitude of the diffusion current indishycating that the mercury surface (cathode) was polarized rather than the anode surface In the second test the concentration of the ferric ion was doubled but no concomitant increase in diffusion current was seen Since the diffusion current is directly proportional to the concentration of the limiting km (Fe1) the current should haw doubled The only explanation for this behavior is that the Fe had been reduced by some contaminant in the system possibly present in the mershycury This would have caused ferric ions to be present at only a wry low concentration during ceD operationdue to electrolytic oxidation of the ferrous iron
To ebminate the possibility of reductant being present in the mercury a supply of purified mercury was obshytained from the Analytical Chemistry Division A test was performed using the purified mercury and an elecshytrolyte having the same nominal Fe and Fe concenshytrations given abow Preparation of the electrolyte was completed in the absence of oxygen to preclude posshysible oxidation of Fe to Fe Again the anode surshyface area was decreased with no discernible decrease in the diffusion current indicating that the mercury surshyface was polarized An increase of the Fe concentrashytion from M)25 vnM to Mgt3 mW resulted in an inshycrease in the diffusion current by a factor of 2 indishycating that the waw being measured was the ferric ion reduction waw However the half-wave potential was measured to be -07S V vs SCE which is about three times the reported value
To calculate the aqueous-film mass transfer coeffishycient from poiarographic data the bulk concentration of the oxidized species must be accurately known The
n a n K amp j f a u f l l O u l a m m anuCntSnafsEafannTuB a m m nWanuWOnBTBsnnnnnT- ana^ne-w w ^ m w u^m w ^ p p ewajuajuaawmimaaaBmniw ma mi awnwaawgt^pwnnawBwanpap wa^anu
the electrolyte used in dm second of the two ter^jaen-tkmed abow woe analyzed for F e v asm F by this method Results hnhcatrd that the fie and Fe conshycentrations were 17 and 028 mMrespectiwry which is in poor agreement with the expected values of 030 ajtf Fe and 1J0 mmf Fe2 One poanok cause for the poor agreement is that the Ft 1 was oxidized to Fe during the period when the solution was held in the sample bottles However this was not expected since the dec-trotyta had been sparged with argon to remow dissolved oxygen and the sample botdes were purged with argon toremowair
To aid in oetennming if the reported analytical results were in error due to analytical technique or to method of solution preparation two standard solutions were prepared and sampled for analysis One solution was prepared to contain 56 ugim Fe and the other solushytion was prepared to contain 56 ugnd Fe1 Both solushytions were 1 WmKjCzO^HjO Subsequent analytical results indicated that both solutions had essentialy the same concentrations of Fe3 and Fe 1 50 and 27 fignil respectively Farther investigation wnl be necessary to determine the correct method for preparing andor analyzing iron oxalate solutions
Experiments with the qwmame-bydroonmmae system A possible alternate to the Fe -Fe system for measshyuring electrolyte-phase mass transfer coefficients is the reversible reduction of quinone to hydroquinone at the mercury cathode
The reaction under consideration is
C r l 4 0 + 2 H 4 + 2laquo-CHlaquo(OH) ( I )
Since hydrogen ion as wen as quinone is a reacting material a strong buffer must be present to serve as a supporting electrolyte The buffer causes the H conshycentration to be essentially constant across the inter-facial electrolyte film because the rate at which the buffer equilibrium is established is reiatiwfy rapid comshypared with the quinone diffusion rate1
A quaUtatiw test was made with the quinone system to determine whether acceptable polarization waves couM be measured and to determine whether the quishynone electrolyte is inert to mercury The electrolyte was 001 M hydroquinone and 0005 M quinone with a 0O5 M phosphate buffer at a pH of 70 Satisfactory polari-
16 i M Kolfhoff and 11 Latcanc p 44 inbfaromvp Intencfcnce New Yortt 146
I C A Lin el at Dirruson-Controiled Electrode Reacshytions Ind Eng Ckem 43 2136-43 (1951)
1S2
abon waves were obtained in a small cell with a large copper anode and a mercury pool cathode The electroshylyte was chemically inert to mercury during the tests The color of the quinone electrolyte changed from a light yellow to deep brown within several hours This phenomenon is due to the decomposition of quinone by ultraviolet light Further studies in the S X 7 in contacshytor will be done to determine whether tins system is suitable for mass transfer measurements
8 3 C0NTTNU0USFLU0IUNATOR DEVELOTMENT
R B Lindaucr
Continuous fluorinators arc used at two points in the reference flowsheet for MSBR processing The first of these is the primary fluorinator where 99 of the uranium is removed from the fuel salt prior to the reshymoval of 2 J J P a by reductive extraction The second point is where uranium produced by decay o f 2 Pa is removed from the secondary fluoride salt in the protacshytinium decay tank circuit These fluorinators will be protected from fluorine corrosion by frozen-salt layers formed on the internal surfaces of the fluorinator which are exposed to both fluorine and molten salt To keep frozen materia on the walls while maintaining a molten-salt core in the fluorinator an internal heat source is necessary to support the temperature gradient Heat from decay of the fission products in the salt will be used in the processing plant However to test frozen- JI fluorinators in nonradioactive systems
another internal heat source which is not attacked by fluorine is needed Since electrolytic or autoresistance heating of molten salt has proven to be a feasible means fx providing this heat source studies of auforesbtance ucating of molten salts are continuing A conceptual design was made for a continuous fluorinator experishymental facility (CFEF) to demonstrate fluorination in a vessel protected by a frozen-salt film Design was comshypleted and installation was begun of a fluorine disposal system in Building 7503 which uses a vertical spray tower and a recirculating KOH solution Installation was completed of equipment to demonstrate the effectiveshyness of a frozen-salt film as protection against fluorine corrosion in a molten salt system
8 J I autafetmi and Initial Operation of Aaloteststance Heating Test AHT-4
Equipment for autoresistance heating test AHT-4 was installed in ceil J of Building 4S0S fai this system (Fig 84) molten LiF-BeFj-ThF (72-16-12 mole 7r) is cirshyculated by means of an argon gas lift from a surge tank to a gas-liquid separator from which the salt flows by gravity through the autoresistance electrode through the test vessel and returns from the bottom of the test vessel to the surge tank The test vessel (Fig 85) used in experiment AHT-3 was decontaminated equipped with new cooling coils heaters and thermocouples and reinstalled for experiment AHT-4
The test vessel is made of 6-in sched-40 nickel pipe with a 44-in-)ong (II-m) cooled section from the elecshytrode to below the gas Inlet side arm The cooled secshytion is divided into five separate zones each with two
Oflm 0tJngt 79mdash4W5
bullbullOfF-CAS-
j M M N m laquo$urr|
SCMMTOft
JT~f
i II lraquo li II I I I I
Hi
HEAT FLOWMETER
AUTOMESISTANCC HCATIN6 POWER
SUff lV TEST
VESSEL
ARGON
Fig SA Ftowdwet for autoresifUncc heating test AHT-4
153
Ffc85 AHT-4 lest vewd
154
parallel coils through which an air-water mixture flows The gas outlet section above the salt level has an inshycreased diameter for gas-calt disengagement and is made of 8-io sched-40 pipe The surge tank has a 46-m4ong (I _2-m) 6-in-diam (01 S-m) section to provide submershygence for the gas lift The upper section of the surge tank is 24 in (0-61 m) in diameter and provides suffishycient capacity to contain the salt inventory for the enshytire system The gas-liquid separator is an 8-in-diam (O^Om) conical-bottom vessel with baffles and York mesh in the upper part for gas-liquid disengagement m the heat flowmeter the salt is heated by an internal cartridge heater and the flow rate is calculated from the heat input and ihe temperature iise of the uit stream
The system is started up by heating the equipment and Hnes to 600C (873degK) The argon gas lift is started and initially the salt flow rate is determined by the decrease in surge-tank liquid level After the salt levels in the tank separator and test vessel are constant cooling of the test vessel is started The resistance beshytween the high-voltage electrode and the test vessel walls is checked periodically by applying a low voltage
to the electrode and measuring the current As cooling progresses this resistance wul increase until the point is reached where heat can be produced in the salt at a significant rate (several hundred watts) without cauang a reduction (shorting) of the resistance
The 80-liter salt batch was charged to the surge tank and after minor modifications to the heating system operation was started Four preliminary runs were made lasting from 4 to 12 hr (from the time the gas lift was started until plugging occurred) In the first run plugging apparently occurred in the electrode when the liquid level in the separator fefl too low to provide sufshyficient head for flow to the test vessel
Salt flow in the second run was much smoother and circulation continued for 11 hr without adjustment of the gas lift During this time the test vessel was being cooled and the salt flow rate slowly decreased by V7 from 450 to 425 cnvVmin This was probably caused by an increase in salt viscosity a buildup of frozen salt in the test vessel or a combination of the two The steady salt flow rate and higher salt temperature fgt873 0K and 20-3TK higher than in run No 1) kept the electrode from freezing but the heat supply at the bottom of the test vessel was insufficient to keep the salt outlet from freezing which terminated run 2 The resistance beshytween the high-voltage electrode and the vessel waO increased from 001 to 0X1812 but autoresistance heatshying was not attempted The vertical portion of the test
section had been cooled to 639degK (sobdus temperature 623degK)
Before the third run the output of the powerstat conshytrolling the test vessel bottom heaters was increased by 44 to keep the salt outlet above the freezing point The ran was terminated by salt freezing in the elecshytrode This resulted from too low a salt flow rale (the heat flowmeter was inoperative because of a burned out heater) and too low an initial temperature (723degK vs 823degK in the second run) in the vertical section of the side arm through which the electrode passes
The fourth run was started with some heat on the vertical section of the side arm This section was unshyhealed prenocty As coohng progressed the bottom heaters on the test vessel were inadequate at the salt flow rate being used Increasing the salt flow rate preshyvented freezing at the bottom of the test vessel After 754 hr of operation the liquid levels in the separator and test vessel started to increase indicating salt flow probshylems both at the inlet and exit of the test vessel Alshythough the salt resistance had only increased from OX) I to 003 ft and the average test vessel wall temperature (in the cooled zone) was 658degK autoresistance heating was suited This freed the plug in the electrode allowshying salt flow from the separator to the test vessel and the increased flow raised the test vessel bottom tempershyature and flow resumed from the test vessel However salt flow rates were erratic for the next 2 hrand 9K hr after the start of the run the tert vessel level started to rise indicating a frozen salt restriction in the vessel It was decided to try to transfer the molten salt from the test vessel to the surge tank before complete plugging occurred This was done successfully and 56 liters of salt was transferred to the surge tank After cooling radiographs were taken of the test vessel by the Inspecshytion Engineering Department using a 35-Ci J l r source In the test section of the test vessel radiation penetration was insufficient to permit measurement of the film thickness The bottom of the vessel between the salt outlet and the gas inlet was free of salt as exshypected and the radiograph of flu top of the vessel showed a 25-mm-thick ring of salt above the normal liquid level This is salt deposited on the colder pipe wall by the action of the gas bubbling through the salt Calculations from the volume of salt transferred indishycated an average film thickness of 45 mm (a 65-mm-diam molten core) The salt resistance at the end of the run was 018 ft and the maximum autoresistance heatshying used was 450 W
The main problem seems to be the forming of a unishyform salt film Near the electrode where the hot molten
155
salt enters cooling is much slower than in the vertical section above the gas inlet It is probably in the vertical section where the salt flm becomes too thick and reshystricts the salt flow
8J2 o f Facaty(CFEF)
The purpose of the CFEF is to measure the perforshymance of a continuous fluorinator which has frozea-wali corrosion protection in terms of uranium removal The uranium which is not volatilized but is oxidized to UFs wfll be reduced back to UFlaquo in a hydrogen reducshytion column The facility wul be used to obtain operatshying experience and process data including fluorine utilishyzation reaction rate and flow-fate effects and to demonstrate protection igainst corrosion using a frozen salt Aim
The facility will be installed in a ceD in Buflding 7503 to provide beryllium containment The system wfll conshytain about 8 ft 3 (023 m J ) of MSBR fuel carrier salt (72-I6-I2 mole 3 LiF BeF -ThF4) containing OJS mole ltpound uranium initially The salt wiD be circulated through the system at rates up to 50 of MSBR flow rate (67 X I 0 m 3xc) Because of the short fluorishynator height (1 to 2 m) the amount of uranium volatilshyized will be between pound0 and 95 per pass The variables
of salt flow rate fluorine flow rate and fluorine conshycentration wil be studied by measuring the UFlaquo conshycentration in the fluorinator off-fas stream and by sam-pKrg the salt stream after reduction of UF to UF 4 The fluorinator laquo 4 have two fluorine inlets to provide data for determining the column end effects Reduction of UF 5 war be carried out in a gas lift in which hydroshygen will be used as the driving gu and also as die reduc-tant If additional reduction B required tins can be done in the salt surge tank The surge tank is designed to provide sufficient salt inventory for about 10 hr of fluorination with 95$ uranium volarihntion per pass About 99 of the uranium should have been removed from the salt batch after this period of time
The faculty flowsheet is shown in Fig 86 Salt wil enter the fluorinator through the electrode m a side arm out of the fluorine path The electrode flange wil be insulated from the rest of the fluorinator and the auto-resistance power wiD be connected to a lug on the flange The salt wfll leave at the bottom of the fluorishynator below the fluorine inlet side arm The fluorinator wall wiD be cooled by external air-water cons to form the frozen salt film which wfll serve the dual purpose of preventing nickel corrosion and of providing an electrishycally insulating film for the autorcsistance current Below the fluorine inlet the fluorinator waB will not be cooled and the molten salt wul complete the electrical
TO FLuomnc ftSPOSM STSTU
JVTO-K S S T M C C ~ T M M
TCU f
ifSEMMUl
r-Gf=imdashlaquobullmdash^ni
TOorr-cts
^ - bull I I I T Z
FMCZC VMVC
MPWCTNM COLUMN
CAS-LIFT
HVOMMCR
rO F K M I VMVI
Fit HA Conf immu flaottnalor experimental facility flow Acer
156
OfML DWG 75-15057
FLUOMNE-CONTMHNG U S
TO N 0 T OFF-GAS SYSTEM
Fjs87 Ftmnmt4mfpmtwfmtm
nrcuit to the vessel wall Since all of the uranium will not be volatilized from the salt there will be some UF 5
in the salt at the bottom of the fluorinator The luori-nator bottom exit line and reductio- column will be protected from the highly corrosive UF 5 by gold lining or plating The molten salt containing UF S will enter the bottom of the column where the salt wit be conshytacted with hydrogen The hydrogen will enter through a palladium tube which will result in the formation of atomic hydrogen and greatly increase the reduction rate to UF 4 The hydrogen reduction column will also act as a gas lift to raise the salt to i gas-liquid separator The salt will then flow by gravity to the fluorinator through a salt sampler surge tank heat flowmeter and electrical circuit-breaking pot Off-gas from the separator which contains HF and excess hydrogen will pass through an NaF bed for removal of the HF Uranium ixxafluoride from the fluorinator will also be removed by NaF Mass flowmeters before and after the NaF beds will be used to continuously measure the UFA flow rate
83J Fluorine Disposal System for Building 7503
The CFEF (Sect 832) will be the first test of the frozen-wall fluorinator using fluorine For the disposal of the excess fluorine a vertical scrubber is being inshy
stalled in Building 7503 A flow diagram of the system is shown in Fig 87 The scrubber is a o-in-diam 8-ft-bJgh (015- by 24-m) Mond pipe with three spray nozzles in the upper half of the vessel The surge lank contains 200 gal (09S m) of an aqueous solution conshytaining 15 wt KOH and 5 wt Kl This equipment is designed to be able to dispose of one trailer of fluorine (18 std m 3 ) at a flow rate of 12 scfm (9 X 10 std msec) The KOH solution wil be circulated through the spray nozzles at a total flow rate of 15 gpm (OJOOI msec) The fluorinator off-gas stream will flow cocur-rently with tnis stream The scrubber exit stream passes through a photometric analyzer for monitoring the efficiency of the scrubber
8J4 Frozen-Wafl Corrosion Protection Denomtration
Equipment has been installed for demonstrating that a frozen salt film will protect a nickel vessel against fluoshyrine corrosion ty preventing the NiFj corrosion prodshyuct film from being dissolved in the molten salt A small vessel containing 6 X I 0 1 m 1 of molten LiF-BeFj-ThF4 (72-W 12 mole ) will be used for the demonshystration (Fig 88) The fluorine inlet consists o hree concentric tubes which provide a path for an air coolant
157
FLUOraquoK IN
JL
SALT IXVCL-
OuT
- raquo F L laquo O M OUT
FlaquoSJ Ffi
stream that will be used for freezing a salt film on the outside of the outer tube The wall of the inner lube through which the fluorine will flow is 31 nils (079 mm) thick The inner lube of the fluorine inlet will not be protected from corrosion The vessel wall is also unprotected but is 280 mils (711 mm) thick Fluorine will be passed at a low flow rate (-v830 mmsec) through the salt until failure occurs which is expected in less than 100 hr at the tip of the probe near the gas-liquid-foiid interface Wall thickness measurements before and after the demonstration will show to what extent the salt film afforded protection
A flow diagram for the system is shown in Fig 89 The argon back pressure will be recorded to provide an ndication of corrosive failure Failure of the tube below
the salt film will allow some salt to leak into the argon cooling annulus The salt will be entrained up into the cool portion of annular space causing a restriction to
the argon flow The system waf be designed such that the fluorine flow is terminated automaticaly when either a low argon pressure is detected in the anrndus or when a high argon back pressure occurs
84 FUiaiWCONSnTUnON ENCINEEJUNC OEVELOTMENT
llMCounce
The reference flowsheet for processing the fuel salt from an MSBR is based upon removal of uranium by fluorinatioa to UFraquo as the first processing step 1 The uranium removed in this step must subsequently braquo reshyturned to the fuel carrier sal before i u return to the reactor The method for recombiniag the uranium with the fuel carrier salt (reconstituting the fuel salt) consists in absorbing gaseous UFraquo into a recycled fuel salt stream containing dissolved U F 4 affording to the reacshytion
UF f c(g)UF4ld) = 2UF(draquo laquo2raquo
The resultant UF S would be reduced to U F 4 with hydrogen in a separate vessel according to the reaction
U F ltdgt bull H (ggt = UFlaquo(d) bull HF(ggt (31
Engineering studies of the fuel reconstitution step are being started to provide the technology necessary for
the design of larger equipment for recomputing UFraquo generated in fluorinators in the processing plant with the processed fuel carrier salt returning to the reactor During this report period equipment previously deshyscribed was fabricated and has been installed in the high-bay area of Building 7503 This report describes instrumentation for off-gas analysis including a prelimishynary calibration curve and two alternatives for proshyviding corrosion-resistani gold linings for equipment to be installed later
The nickel reaction vessels presently installed will be used to test the salt metering devices and gas supply systems After the initial shakedown work is completed the UFraquo absorption vessel Hj reduction column flowing-stream samplers and associated transfer lines will be replaced with gold or gold-lined equipment Gold is being used because of i u resistance to corrosion by UFraquo gas and U F dissolve in the salt
1972 18 Chem Technol Dh Anim frogr Kept Mar SI ORNL-4794p I
19 R M (ounce Engineering Development Studies for MolenStll Breeder Reactor Processing So 19 ORNL-TM-4863 (July 1975) pp 38 42
158
OMN M 6 rS-OTM
FCV-3 nOccWM HASTMGS MASS FLOWMETER
ACTIVATED ALUMNA TRAP
Ffeft9 FfocM ait BtotaciiMi
841 for Analyzing Vest Off-Goes
The equipment for the second phase of the experishyment will consist of a feed tank a UF absorption vesshysel an Hj reduction column flowing-stream samplers a receivei tank NaF traps for collecting excess UF and for disposing of HF gas supplies for argon hydrogen nitrogen and UFraquo and means for analyzing the gas streams from the reaction vessels (Fig 810) The equipshyment wul be operated by pressurizing the feed tank with argon in order to displace salt from the feed tank to the UFlaquo absorption vessel From the UFlaquo absorption vessel the salt flows by gravity through a flowing-stream sampler into the H2 reduction column From the Hj reduction column the salt flows by gravity through a flowing-stream sampler to the receiver tank Absorption of gaseous UF t by reaction with dissolved UF 4 wiD occur in the IFF absorption vessel and the resultant UF5 will be reduced by hydrogen in the Hi reduction column The effluent salt is collected in the receiver tank for return to the feed tank at the end of the run
The off-gas from the absorption vessel and the reducshytion column will be analyzed for UF and for HF reshyspectively
The respective off-gas streams will be continuously analyzed with the use of the Cow-Mac gas density balance A sample stream is taken from the main off-gas stream and passed through the balance for analysis (Fig 811) These analyses wiO be used in determining the efficiencies of UF absorption and H 2 utilization
The efficiency of UF absorption will be determined by metering UF and Ax to the UF reaction vessel and determining the UF content in the vessel off-gas using a model 11-373 Cow-Mac gas density cell2 The H utilization will be determined similarly Hydrogen will be metered to the H 2 reduction column and the column off-gas wD be anayzed for Hj content also using a model 11-373 Cow-Mac gas density ceD The Cow-Mac cell commonly used as a gas chromatograph
20 Gow-Mac Instrument Company 100 King Road Madison New Jersey
159
bullWLDIN6
bull SYSTEM
Flaquo SIO Ftow lt ^ w o gt n ^ w i l M
msw NEACnON VflaquoSCL
P9E Y
f OWL DUG 7VS909
0FF-6AS
j r _^DT
KOC
ROTCTER|V] $
Ffc 811 SdMMMtic M of fMl ncomtitalfcM experiment off-gn
160
detector provides a continuous signal which varies directly with the density of the sample gas allowing continuous analysis of the sample gas stream with accushyracies of 3 to 4ft Because the detector elements are not exposed to the sample stream the gas density cell is useful in analyzing corrosive gas mixtures
Nitrogen and argon will be reference gases for the gas density cells used for analyzing the off-gas from the UF absorption vessel and the H reduction column respectively The response of the gas density cell is fairly insensitive to changes in the sample gas flow rate when nitrogen or argon is used as a reference gas2 z To measure varying Ar-UF and H2-HF ratios with the gas density detectors it is necessary to control the refershyence gas flow rate precisely However Irigh precision is not required for controlling the sampie g^ flow rate The reference gas flow rates are controlled sufficiently by rotameter and separate gas supply systems A satisshyfactory means for providing reproducible sample flow rates has been developed The sample stream is taken from the main off-gas stream (Fig 811) and flows through a capillary tube the gas densiiy detector an NaF trap to remove the corrosive constituent (UF or HF) and a bubbler to provide a constant downstream pressure The pressure upstream from the capillary is maintained at a higher constant value by means of a similar bubbler in the off-gas line downstream from the NaF trap The NaF traps provide sufficient volume in the lines so that small pressure fluctuations from bubshybles in the process vessels and in the bubblers are effecshytively damped out The flow rate is not constant (although it is reproducible) because as the concentrashytion of the sample gas changes its viscosity changes producing changes in sample flow rate under the prevailshying conditions These flow rate changes superimposed upon concentration changes in the sample stream to the gas density detector result in a nonlinear response of the gas density detector to changes in concentration The effects are reproducible however and a reproducible calibration can be obtained Such a calibration was obtained with mixtures of hydrogen and nitrogen (Fig 812)
For sample gases containing hydrogen and at refershyence gas flow rates below a certain critical flow rate hydrogen will diffuse countercurrently into the refershyence gas stream to the area of the detector elements
21 J T Wjfoh and D M Roue tor Oiromalofr US) 232 40 17)
22 C L Ouillemm and M K Auricourf (its Chromalogr I 24 29 (October 1963)
onw MG re-mo
i i i 1 bull mdash I I I I i DO 90 0
2
Ffc 812 Cafeoraam i laquo of Gow-Mac gas Oettmtf ccM MOM in fad iccoasMatioa t^mtimj claquojlaquoipmlaquoi for H ami N-
Due to the high thermal conductivity vf H the back diffusion of H can greatly affect the sensitivity of the gas density cell However if sufficiently high reference flow rates are maintained this problem can be overshycome
842 Design of the Second Fuel Reconftitutkm EjtgMecimg Experiment
The design of equipmeni for the second fuel reconsti-lution engineering experiment (FREE-2) is continuing The equipmeni for FREE-2 will be similar in design to the equipment for experiment FREE-I except for the addition of an intermediate liquid-phase sample port beshytween the UFraquo absorption vessel and the H 2 reduction column (Fig 810) In addition all vessels and transfer lines exposed to dissolved UF 5 with the possible excepshytion of the receiver lank will be gold or gold lined Gold sheet 0010 if (02S mm) thick is on hand for the fabricated liner of the UF absorption vessel Two altershynative exist for lining the H 2 reduction column and the receiver vessel interior gold plating or a fabricated gold liner
The minimum plating thickness that would probably provide a pinhole-free liniig is approximately 0005 in (013 mm) The minimum thickness for a fabricated gold liner in vessels of this size is approximately 0010
161
in (025 mm) Fabricated gold liners are economically competitive with gold plating in the thicknesses menshytioned because gold sheet is available at ERDA prccious-mctal account prices approximately S3499troy oz (SII3g) and gold in commercial gold-plating solutions is available only at market prices of about Sl64troy oz (S5J7g) as of June 18 1975 Some comparisons important in the choice between interior gold plating or fabrication of a gold liner are
1 the technology involved in fabricating a welded gold vessel is available while some technology would need to be developed for interior plating of vessels having a high lengthdiameter ratio such as the H2
reduction column 2 the time involved in both approaches is approxishy
mately the same 3 the plating will be difficult to inspect and there will
be no guarantee of pinhok-free coverage while dye penetrant examination of welded joints is available for a fabricated liner
Because it is unclear whether there is sufficient gold in the ERDA precious-metals account for lining the reshyceive tank liner gold plating is favored There is the ziditional alternative bullbull not lining the receiver tank since i orrosion of the receiver vessel by UF5 in the salt could ie tolerated and corrosion products could be reshymoved by hydrogen reduction and filtration between runs
85 CONCEPTUAL DESIGN OF A MOLTEN-SALT BREEDER REACTOR FUEL PROCESSING
ENGINEERING CENTER
D I Gray J R Hightower Jr
A conceptual design is being prepared to define the scope estimated final design and construction costs method of accomplishment and schedules for a proshyposed MSBR Fuel Processing Engineering Center (FPEC) The proposed building will provide space for the preparation and purification of fluoride sail mixshytures required by the Molten-Salt Reactor Programfor intermediate- and large-scale engineering experiments associated with the development of components reshyquired for the continuous processing capability for an MSBR and for laboratories maintenance work areas and offices for the research and development personnel assigned to the FPEC
bullORNI Knpneeriti Division
The project wSI consist of a nev three-story engineershying development center approximately 156 ft (475 m) wide by 172 ft (524 m) long The building will have a gross floor area and volume of 54300 ft 2 (5100 m x ) and 1218J0O0 ft J (34300 m J ) respectively and vhB be constructed of reinforced concrete structural sled concrete Mock masonry and insulated metal paneling The building will be sealed and will be operated at negashytive pressures of up to 0 J in of HjO (75 Pa) to provide containment of toxic materials The FPEC wit be located in the 7900 area approximately 300 ft (91 m) west-southwest of the High Flux Isotope Reactor The engineering center will contain
1 Seven multipurpose laboratories buu on a 24 X 24 ft (7 J X 7 3 m) module for laboratory-scale experishyments requiring glove boxes and walk-in hoods
2 A high-bay area 84 X 126 ft (256 X 384 m) equipped with a 10-ton (9000-kg) crane for large-scale development of processes and equipment for fuel processing at the pilot-plant level
3 A facility for preparing and purifying 16000 kg per ye-r of fluoride salt mixtures needed for the Molten-Salt Reactor Program
4 Support facilities including counting room process control rooms change rooms lunch and conference room and data processing room
5 Fabrication and repair shop decontamination room and clean storage areas
6 A truck air lock to prevent excessive ingress of outshyside air during movement of large equipment items into and out of the high-bay area
7 Two 5-ton (4500-kg) service elevators one inside the building to service the regulated areas and one outshyside to service the clean areas and to move filters to filter housings on the third floor and roof
8 General service and building auxiliaries including special gas distribution systems liquid and solid waste collection and disposal and filtered air-handling and off-gas scrubbing facilities
The experimental program planned for the building involves large engineering experiments that use 2 1 U 2 T h Be hazardous gases i F a H 2 and HF) molten bismuth and various fluoride and chloride salts Inishytially radioactivity will be limited to that necessary for low-level beta-gamma tracer experiments The laborashytory area can later be upgraded if desired for use with alpha-emitting materials at levels up to I kg of n P u
The laboratory area will consist of seven 24 X 24 ft (73 X 73 m) modular-type laboratories and a general-purpose room Bench-scale experiments of the type now performed in buildings 4505 3592 and 3541 will be
162
carried out m these laboratories FtoMems encountered in the large-scale experiments can be studied via smaE subsystems Inert-atmosphere glove boxes wil provide space for examination of samples removed from both the large and the small experiments The laboratory area wul be maintained at a negative pressure of 0 J m of H 2 0(75Pa)
The high-bay area wul be the main experimental area where large engineering experiments wifl be performed Experiments wnl involve circulating mohen mixtures of LiF-neFj-ThF4 lithium chloride and molten Bi-Li alloys The experiments wffl also use elemental fluorine hydrogen fluoride hydrogen chloride and hydrogen gases as reactants and wnl use purified argon for purgshying Excess fluorine hydrogen fluoride and hydrogen chloride wil be neutralized in a caustic scrubber using KOH solutions and the cleaned and filtered off-gas win be ducted to a bunding exhaust system The experishymental equipment and components wil be housed in steel cubicles with floor pans which can contain any salt spJO The cumdes wnl be maintained at a negative presshysure with respect to the high-bay ambient The high-bay area can be supplied with up to 45000 cfm (212 msec) of air The air can be from recirculated inside
air laquo fresh ak from the outside The high-bay exhaust system wil be designed for 30jOOOcfm ( I 4 J msec)at floor level and 50000 cfn (236 msec) at the roof framing level A l exhaust ducts wnl contain fire barriers upstream from the double HEP A filter banks
The salt preparation and purification area wil consist of a 25-ft-wide by 3S-ft4ong by 14-ft-hJgh (76 X 107 X 4J m) raw materials storage room a 22 X 22 X 28-ft-high (67 X 67 X 8J m) room for weighing and blending the salt constituents and a 40-ft-wide by 45-ft-loug by 28-ft-high (122 X 137 X 85 m) room for melting rk-HF treating and filtering the fluoride salt mixtures This facility should be capable of producing I6j000 kg per year of fluoride salt mixtures using the batch processing method in use at the (acuity at Y-12
The estimated cost for the FPEC is SI 5000000 of which $5200000 provides for inflation during the three years required for design and construction of the baking
The design is essentially complete and the conceptual design report is scheduled to be issued in September 1975 Authorization for this project will be proposed for FY 1978
Part 5 Salt Production
9- Production of Fluoride Sak Mixtures I
F L Daley
A salt production facility is operated by the Fluoride Salt Production Group for preparation of salt mixtures required by experimenters in the MSR Program The group is responsible for blending purifying and packshyaging salt of the required compositions
Much of the salt produced is used in studies on Hast el -loy N development in which the concentrations of metal fluorides particularly nickelironand chromium are important study parameters Ic is thus desirable to use salt in which the concentrations of these metal fluorides are low and also reproducible from one salt batch to the next Oxides are undesirable salt contamishynants primarily because of the adverse effect of uranium precipitation and also because of the effect of oxides on corrosion behavior of the salt Sulfur is another conshytaminant present in the raw materials used for preparing salt mixtures Sulfur is quite destructive to nickel-based alloys at temperatures above 350degC because a nckel -nickel sulfide eutectic which melts at about 645degC penetrates the grain boundaries and leads tc inlergrlaquonu-lar attack of the metal The maximum desired ievels for these contaminants in the fluoride salt mixtures are iron 50 ppm chromium 25 ppm nickel 20 ppmsulshyfur lt5 ppm oxygen lt30 ppm Other duties of the group include procurement of raw materials construcshytion and installation of processing equipment and reshyfinement of process operating methods based on results from operation of the production facility
When the facility was reactivated during 1974 initial production was carried out in existing small-scale (8-in-
bullConMiliam
r MSR Program Research and Development
RWttorton
diam) reactors while new large-scale (I2-in-diam) reacshytors were eing installed Experience with both the small and laige units is summarized in the remainder of this chapter
91 QUANTITIES OF SALT PRODUCED
The 3-in-diam reactor was used for production from startup of the program in early 1974 through the first three months of 1975 During this period a total of nine full-scale batches (315 kg total) were processed and made available to investigators Salt from the nine batches was shipped in a total of 2i containers of apshypropriate sizes In general operation of the 8-in-diam reactor proceeded smoothly and the resulting salt was of acceptable composition and purity
Production in the 12-in-diam reactor was started in March 1975 Five production runs each involving about 150 kg of salt have been carried out Of the five salt batches processed four were suitable for use most of the salt from these four runs was used for fuel procshyessing experiments In contrast to the earlier runs in the 8-in -diam reactor difficulty has been observed in the 12-in-diam reactor with corrosion of dip lines in the meltdown vessel and with increasing concentrations of metallic impurities in the product salt
92 OPERATING EXPERIENCE IN l2-in-diani REACTOR
Operating data from the five production runs in the 12-in reactor are summarized in Table 91 Analyses of the resulting salt batches are given in Table 92 A description of the processing operations and conditions
164
TaMe9l ttoccMag fab derived fto to rave taae ami titntioa of iafci aad oatlet flows
Batch number (FS-)
Batch size
ltkgt
Total tarn Ihr)
HF in
(moles) in
(motes)
HF out
(molest
HF reacted (moles)
Dariag hydmlhoriaatiMi 101 150 125 1953 4253 1712 241 102 150 1025 2331 2738 2331 0 103 150 975 1808 2603 1419 389 104 150 95 2853 2473 2434 399 105 12 140 3752 2857 1877 1876
Batch number |FS-)
Batch size
Total time
Total H in
Total HF out
HF in otT-jraquos Imeq per liter of H) Batch
number |FS-) Ike) (hr) (moles) (moles) Start Finish
Daring hydrogen ledacliua
101 150 176 4725 0026 00018 00064 102 150 186 4995 0595 0100 0O50 103 150 244 6520 1560 0625 0016 104 150 440 12040 2180 0746 0008 105 112 320 8514 3290 0476 0102
Table 92 Aaatyxsof 1501 batches of LiF-BeF -ThF4 (72-16-12 mole )
prodaced in die 12-araquo learior
Batch number (FS-)
Analyses Batch
number (FS-) Li r)
Be Th F rlt)
Fe (ppni)
Cr (ppml
Ni (ppml
S (ppnw
O (ppm)
Nominal 72-1612 790 228 4411 4571
101 795 252 4392 4620 82 24 17 737 lt25 102 8 64 222 4200 4600 75 30 600 80 360 103 811 231 4327 4574 60 25 8 25 350 104 839 200 4381 4532 85 65 10 91 NO 105 1046 290 3435 5125 82r 25 8 576
prevailing during hydrofluorination and hydrogen reduction is given in the remainder of this section
921 Charging and Metting of Raw Materials
The salt produced in the l2-laquoi-diam reactor has been of the MSBR fuel carrier salt compostion (72-16-12 mcle LiF-BeFj-ThF4) production of salt of this composition will continue except that some batches will also contain 03 mole UF 4 If the production schedule permits an inventory of non-uranium-bearing salt will be accumulated before beginning the producshytion of uranium-bearing salt The LiF raw material for
the salt production facility is supplied by Y-12 as needed the BeF2 and ThF 4 are taken from raw mateshyrials that have been on hand for several years The only apparent effect of the long storage time on the raw materials is an increased moisture content of the BeF2
The production unit includes two l2-in-diam 72-in-high type 304 stainless steel vessels each of which is (Wed internally with a full-length open-top copper cylinder in which the salt is contained One vessel is used for batch melting of the raw material) which are charged to the meltdown vessel by gravity transfer through a 2-in-diam pipe the pipe extends into a weighing and charging room and is closed by a sealing
165
flange except during the loading operation The second unit the processing vessel is identical to the meltdown vessel except for the charging line Both vessels are fitted with dip lines for introducing gas to the bottom of the vessels for mixing or purifying a salt batch and both are connected to an off-gas system Each vessel is supported in a stainless steel liner and while in use is located in a heavy-duty electrical furnace The receiver vessel to which the salt product is transferred is 12 in in diameter 36 in high and is supported similarly in a furnace adjacent to the processing vessel furnace Salt transfer lines from the meltdown vessel to the procshyessing vessel and from the processing vessel to the reshyceiver are autoresistance heated via a 24-V power supply
The operational sequence includes salt charging meltshying and mixing in the meltdown vessel and transfer of the resulting salt to the processing vessel for purificashytion The process steps include hydrofluorirution hydrogen reduction and filtration during transfer of the purified salt from the processing vessel to the receiver vessel During both the hydrofluorination and hydrogen reduction steps the receiver and processing vessels are maintained at the same temperature and the process gases are passed through the receiver before being fed to the processing vessel in order to eliminate any oxide film on the interior of the receiver
The raw materials are loaded into the meltdown vessel by technicians wearing air suits having a supply of cooled fresh air The work is carried out in a small enclosed room in which containment is maintained by positive flow of air through the room to a bank of absolute filters The appropriate quantities of each of the raw materials are weighed and charged through a loading chute directly into the l2-in-diam melidown vessel which is at room temperature The larger lumps of BeF 2 and occasional lumps of LiF are broken by hand to facilitate loading and to provide improved mixshy
ing The ThF 4 is a fine powder which does not require six reduction The charging method leaves much to be desired melting would be more rapid and more predictshyable i f the particle size of the raw materials could be reduced and all components mixed well before they are charged to the meltdown vessel
Some of the more important impurities in the raw materials are listed in Table 9 3 The values shown are average values in most cases The metallic impurities are satisfactorily low however sulfur and possible silicon contribute to corrosion problems during melting of the raw matercls The moisture content of the raw mateshyrials is not shown but is an important parameter It is believed that hydrolysis of the fluorides during the initial heating period generates hydrofluoric add which subsequently reacts with sulfur- and silicon-containing compounds in the raw materials to form hydrogen sulshyfide and fluoroalidc add The quantities of these mateshyrials produced appear to be dependent on the temperashyture at which the meltdown vessel is held during the initial portion of the melting operation with 2 S proshyduction being most noticeable at temperatures above S00degC An addic compound which contains silicon and fluorine is evolved freely at lower temperatures in the 125 to 500degC range however the extent to which the material is corrosive to the meltdown vessel is not known Analytical data necessary to determine whether these low-temperature gases contain sulfur-bearing comshypounds are not available
The major effect of hydrogen sulfide on nickel comshyponents at temperatures in the rage 600 to 700degC is rapid eirbtlement of the nickel This action has resulted in breakage of dip legs in the meltdown vessel at the rate of one dip leg per run Breakage v observed to occur in the gas space above the melt and the broken dip leg falls to the bottom of the meltdown vessel where it is available for further attack by corrosive material) dissolved in the salt After melting batch
TaMe 93 Impr i t in tm raw material mtei ia ftmoriit a l t production (ppm)
Component S Si Fe Cr
Component Av Max A Max Av Max AVK Max
L i l 21 44 100 IllO 20 25 lt l lt l BeF 300 500 IHO I0O 50 100 20 40 rl ir- lt M 0 ltIO0 lt IO ltin 25 62 I I 17 Mixed raw
material^ ino 131 47 47 26 56 9 15
Mix ture required to produce tali havirfi compofll ion of 72-16-12 mole i I i l - B e l - I h i -
166
FS-101 was passed through a nickel filter having a mean pore size c f 40 i but plugging of the filter on subshysequent transfers led to its removal from the system Transfers from the meltdown vessel are now made after allowing a period for particulate material to settle
A stainless steel dip leg was used in the meltdown vessel during the melting of batch FS-105 in an attempt to avoid cracking of the dip leg The use of stairJlaquolaquo steel was liter concluded to be unsuitable because of the increased concentrations of iron and chromium observed in the resulting salt product The dip leg did not embrittle nor break during melting of the salt but extensive corrosion was noted on the submerged porshytion of the leg As a result of these observations a dip leg of copper and nickel was constructed by placing a copper sheath over a heavy-waD nickel tube The nickel tube provides rigidity and the copper is used both outshyside and inside of the nickel tube to obtain resistance to corrosion The copper sheaths are welded together at the lower end of the dip leg located in the meltdown vessel This combination of materials is expected to result in an increased dip leg life and less contamination of the product salt
An error was made in charging the ThF4 for batch FS-105 which resulted in salt that did not have the desired composition
922 Hydrofluorination and Hydrogen Redaction
After a salt batch has been melted in the meltdown vessel it is transferred at a temperature of about 750degC to the processing vessel where it is sparged with an HF-Hj mixture at a temperature of about 625degC for a period of about 10 hr The salt is then sparged with H 2
at 700degC the H 2 flow rate of 10 std litersmin used during the hydrofluorination step is continued for 30 lltr to reduce iron and nickel fluorides to their raquoraquopective metals
Progress of the hydrofluorination step is monitored by determining the HF content of the HF-Hj inlet and exit gas streams by absorption and titration of the HF in a metered volume of exit gas When the HF concenshytration of the inlet and exit streams becomes equal (or the concentration in the exit stream becomes slightly higher than that in the inlet stream) contact of the salt with the HF-Hj mixture is stopped A relatively low temperature about I00degC above the salt liquidiu temshyperature is used to minimize the rate of corrosion of equipment and to maximize the rate at which oxides are hydrofluorinated The hydrofluorination step is folshylowed by treatment of the salt with hydrogen at 700degC
to reduce iron and nickel fluorides The utilization of hydrogen during this step is low and large volumes of H are required Since the reduction reaction releases HF the concentration of HF in the off-gas stream is monitored and hydrogen treatment is stopped when the HF concentration reaches a low value (about 002 meqliter) and remains constant within the detection limits of the titration method
The total gas flows (H 2 and HF)during the processing operations are shown in Table 91 The values in the table reflect a steadily increasing quantity (from FS-101 to FS-105) of HF generated by H2 reduction of metallic fluorides that can be ascribed to a buildup of metals (largely iron and mcke) in the salt heels in the meltshydown vessel and in the processing vessel during operashytion These metals are converted to fluorides during hydrofluorination and thus add to the total quantity of metal fluoride to be reduced during hydrogen treatshyment
9 3 SUMMARY
The information presented in the previous sections indicates that the following factors are important in producing high-quality salt
1 Analyses of the raw materials indicate that there will be no concern with metallic contaminants unless metallic corrosion products are introduced during the salt purification or melting steps
2 The sequential buildup of metallic impurities in the salt produced in the I2-in-diam facility is the result of corrosion of the equipment This corrosion can be minimized by use of copper whenever possible when equipment is simultaneously exposed to salt and process gases Periodic hydrofluorination and discard of flush salt in the processing vessel should control any minor buildup of corrosion products
3 Although not demonstrated by data shown in this chapter it is believed that oxygen contamination can be held at low levels by maximizing the removal of moisture from the raw materials before they are melted and by improving control of the hydroshyfluorination process A method for measuring the H 0 produced by reaction of HF with oxides in the starting materials is being tested This should aid in determining the proper time at which to terminate contact of the salt with the HF-H2 mixture Alsoit may be necessary to determine the sulfur content of the off-gas since this may be the most difficult conshytaminant to remove from the salt
MOLTEN MLT REACTOR PROGRAM AUGUST lraquo4
i I MtfttitSI HHMHAM OIHH UgtM
m D M K M AMD M V I LOMMlaquo1 i n iH tGlL H
svsriMi AO AKAIVHI J N I N C U H
1 j A L L I N H
H 1 K | N lt I N
0 1 M A S M
0 I M I D N
ftWIMt A N C O f t M O M H T l M V I L O M N N I
m M G u laquo laquo O N H
A A H U - t U t l 1 M
W 0 H l V l M f t M N M 4 ft M l i l M H
m bull raquo | N S O N H 1 ftlOOLl N O t I R A V H I N M M bull H O raquo l raquo raquo S O N n
bull F A I M M O N M I M
4 M L V l l C L C M l M i S H V D i V t S i O N C M l W l t t N T D V I K O A j C M l W C A k F I C M A J O L O C J V 0 V gt V O V lt TACS A N D C A A W C S lgt iV traquo iC i M A C T O M ) O i V i S lt O N I X m v l f t S l T V O I I I N N t M I l
A t A H H I A U
M 1 M C O V MAC
M J U H U 0 Y N 1 T U W I I
H 1 I f c C O l MAC D N bull M lt S gt i MAC 1 M K h l S I A D MAC A k C L A J J I N C MAC I I J C X O U t t MAC
1 A U S T M A N G MAC
H l H I I I T A N t l MAC C A H V M A N M J laquo K t i t t H MAC
bull C U S U I MAC
bull M r N A M MAC 1 K R U C M I MAC A C t C M A f raquo M A U S ( H MAC i ft W O O t i S MAC
C M 4 M I C A L M K K I U 1 I M M A 1 I A I A L I
H M U I W V MAC
I I C H N I C A I t U W O I I t
A V HOI I M i MAC C 1 0 o N MAC n M raquo 4 H M t M - MAC 1 C k l l T N t H MAC J t I M i l H I H MAC I M l A r M l H L V MAC
J 1M H I N D I I C K S MAC T t M I N S O N MAC J 0 M ICWON - MAC
1 1 l A M H I X i 1 MAC
1 bullbull I I I MAC A ilaquo M i l l k H MAC (1 A gt 0 1 T1H MAC
I d H A H D O h MAC H H V I A M N O k MAC 1 i X M I M S K V H
tt I I S 1 I N I S MAC C K l i K l M A S MAC 1 H r H D I I I M MAC C A W A l l laquo ( l n 1 1 M K I C I H O I I S I MAC
M M gt H O C I t t l a O I V l l O r W I N I
J H Mt r HT ( )WraquoM IH bull
C M I M I C A l 0 I V I L 0 A M I N 1
A O fttk M l M S M H I I N M M
l O l N l l f t l laquo a O I V l l O H H N 1
gt H H I U H f O W I H JH C M SHOWN m n M c o i m c i c w t i bull H bull U N O A U l H M C S V A lt i
I B I A M S H O P A Y M
M M H C H I M I I T M V
l M M H H i S i A 1) r l L M I H S c L M A V A ( H t M t I C c raquo C A N T O N c I M l M c t O d i LPS T H I C K c raquo A r o i i raquo bull t H N M H O N k l U N t
D 1 H l A T H f R i V 1 O V A L l N l l N I c
A N A L Y T I C A L C H I M l t T N V
M M A A C H A f t O O I V I t O M M I N V
A I M f V I N AC H t A M | t bull AC B H C l A M K AC J M M A L I AC p L M A N N I N l t AC J P T f l U N t t AC
A N A l V S f l
i i I I M raquo I M At t it O o r t M - A l
ft ri i A i N t AC J A C A H I t l f AC
C O N S U L T A N T
r M A M A H t O V I I I
_ -L_ ULTMOOUCTION N M HtWIQN c bull I U A l t v C
bullH i AHVAK C I A c XJHNtOkt C t
