IfM/S-I 1900 6 92-

MEASUREMENT AND EVALUATION OF THERMAL EFFECTSIN THE INTERMIXING ZONE AT LOW POWERNUCLEAR STATION OUTFALL

by

P. R. Kamath, R. P. Gurg, I. S.Environmental Studies SectionHealth Physics DivisionBhabha Atomic Research CentreBombay-400 08 5.

Bhat and P. V. Vyas

Presented at the Waste Heat Management and UtilisationConference, Miami Beach, Florida, Dec. 4-6, 1978,USA 33124.

What* Heat Maaageaeat a adUti l i sat ion Conference,Hlaati Beach, Florida 0«« 4-6,1976.

MSASO&nHf? AND SVAUJillOH OF TBBBMAL SRICTS IT TBBINTERMIXING ZOH! A* LOW POWER IUCLEAR STATION OUTFALL

P.H. Kaaath, R.P. Qurg, X.3. Bhat and P . * . VyaaXavironaantai S ta i laa Seotion

" Health Phyelos B ir i s i onBhabba Atoaio Basaaroh Cantr*

Boabay - 400 065

A83TIA0*

" f b a paper reports obaervatlone and evaluation o f theraal e f f s e t s l a tornt a a a Prattp a«f*r Laka *fl'Rajaatbaa, India wtera « M a n l t (200 flf*) o ftba Bajastbaa Atoaitf^Powar Stat ion u ^ opwrtMab. Tba oaolaat vatavaara dram 8-10 a balow tba laka aurfaoo tftmu^h a ooaduit aad 4iaoaarf«itbroucb an opaa diaabasva obaaaal with a taaaatatora r iaa o f 10*0*fb tra «aa a aaa l l iaeraaoa i s laka «a««r taaparatara'ia tba v i o i a i t y o ftba o a t f a l l * faapavatura p^ofilaa and apraad aoro aappad aa la f iaaitmaooitora, - ' ' " . / ' • .

Vbaaa atodioa abntadLaridanoa of tbemal atratifieatioa la tba parlod .foUowiaK wlntar aaA tha azistaaoa of a well oatfbliabad tbanooliao*!Ibazaal stratifioatioa brought out apaoifio advaatagoa for tbtraalabataaant when tba hypollaaioa «atara wera wall balow, tba toaparatttroof eurfaoe waters.' Farmsitiam and eutropbloatloa waVa (ibeerred. tbatbazaal offaota wa^-oeeentucied by photo»y»thetic affaota. Propoaalto ut i l iaa waata heat for algal oultura la tbo Kalpakkaa xraolear aitala South and aarieultura (Lobstera. Prawoa) l a tba heatad affluaataoaaal at tha larapur Atoaie Power Station near Bombay ara diaoaaaai,7

IITfiODUCTIOS .

7ba fraah water nuolear aita ia operation in India i s in Rajaatbaa oatha River Chambal drawing ita coolant watar froa tba aao aada laka Ra»aPratap S«g»r(BP3). Only one reactor unit of 200 ale i s ooaalsaloaeaVOf tba two coastal s i t e s , the Tarapur Atomic Power Station baa tworeaoters 200 MWo aaob coaaiasioned ia 1970. Xalpakkaa Atoaio Projaotia uadar construction. Monitoring of beat distributioa i a foraaborawaters, asaaaaaoat of tberaal affoots and invwatigatioaa for waata baa*uti l iaatioa ara at present oarriad out by tba Bariioaaaatai SarrayLaboratoriaa inatalled on aaob s i t e .

aATASTBA* ASPOMIO POWER SUB (tAPS)» FIO-1

fba RPS laka i s about J ka wide at tba roaetor s i ta and ezteads to 9hadowaatraaa upto tha Daa. I t receives about 8000 ofa of water as tailiag-froa a Daa located 32 ka upatreaa. VM lake ia l a tba aaia fad by

R Ctaaabai and i t s tributaries. The cooling waters from tte lake aradrawn through a conduit 8-10 • below tba surface and 300 • off a bora.The warm oondtnaar effluent* ara discharged througb a oanal which i sepan and virtually diaohargaa to tba lalea aurfae*.

The water movement in tbe BF3 ia dependant on wind apaad and itadirection. When tba wind apaad ia leas than 8-10 km/far, the lake water*ara atagnant. Th* disohargea remain elo*« to tbe bank at that timeand apraad along gradully. At wind spaeda 15-17 ka/hr there i* aeonapiouou* movement of water on surf age ia the direction of wind. Atapaads greater than 20 k>/&? there ia good turbaleno* and Mixing.

RAPS i i an inland s i t* located ia the oentral part of th* countryaubjected to large diff*r*no*a(iO»1$*C) between day and night air tempera-tures and about 25*0 between peak day temperatures between aumm»r andwinter, Temperature stratifioation in th* lake depends on the a*r*rity ofwinter whioh ia considered aotur* when the air temperature* reach15-18°C at noon.

Stagnancy of water movement in the lake and design of th* oond*na*roirouiation system in HiPS held oat interesting posaibilities of teatbuild up. Torrid summers when air temperatures touohed 39*C and lak*water, 3U9*C at aurfaoe, abowed th* ohanc* of theraai pollution *ff*otsbeing observed attributable directly to th* power atation reject heat.

Mate rials and

I i

The condenser discharge was identified as i t moved along or spread ov*rthe lak* surface by spiking the effluent stream with- fthodaaia* B dye forvisual

T—cerature Matar

An innitn

An insitu temperature meter for taking vertioal temperature profile* wasdeveloped on the tomperatur* dependent characteristic* of a sealoonduotordiod*. Th* systea used matched pair of diodea as t*mp*ratur* •*nsors(*C),Th* rcspons* time i s 80 s*o* for a difference of 25*C. Th* sensitivityi* 0.1*0. Cable reach 20 a.

Bissolvd Otma (DO) Mef r4

f i*ld Lab Oxygen analyser supplied by Backman Instrum*ntst USA was u**dfor 00 aeaaarament la tte laboratory study. Tte In eitu monitor employedla tte field was also obtained from USA.T3I 00 Meter model. Tte dualprobe has a built ia temperature seasor for ia situ moa*uram*at. 00ooao*ntratioa i s read ia ppa or as p*ro*ntaga of aaturation at tte mettemperature. '

Observations - Results

Teaperatures at surface observed daring set hours of the day in thedifferent wraths following winter are presented in Table 1. The tempera-ture readings have to be read bearing in aind that the intake i s obtainedfroa the hypolianion(Elevation 335 a) and the oondenser discharge i s aadeto the surface of the lake. Table 2 i s important because i t gives thebasio water qual i ty change and indicates what happens when water froathe hypolianion goes through • churning aotion in the condenser tubing*Values of 00(as percent saturation), COD and BOD are given in the intakeand discharge streams'. Fig 2 gives the horizontal spread of heatedeff luents giving the different Thermal tones. F ig . 3 gives the ver t i ca lprof i l e s of teaperatures in the different seasons to i l l u s t r a t e theformation of theraocline and i t s gradual disappearance.6

DISCUSSION-EVALUATIONData presented in Table 1 has brought out the laportant features o f theenvironment which go a long way to e f fect thermal abatement* Even as toelaice surfaoe teaperature reached 23,5°C lower than surface, theintuit* waters were oooler than i f the design was a surface intake. Thedifference between the intake water and surface teaperatures (5*3°C) wasgreater than that between condenser intake and disobargeU*3°C)«resultiaga s tat ion output of heated effluents at.one degree ce la ius l e s s than thelake surface temperature. This s i tuat ion continued t i l l peak suaaertemperature was reached in a ir (39°C). In the l a s t week of May there werestray showers which brought in the welcome change in a i r ( a i r temperaturedropped by 4°C 39 to 35) . There was a audden change also in the lakewater temperature prof i l e . After the rains aaae .down jhe pioture changedent i re ly because the lake received plenty of water supply froa hinterlandand tributaries{Fig. 3 for pro f i l e s ) .

Fig 2 gives the different thermal tones around the o u t f a l l . There i s a1*C r i s e in the olose v i c in i ty o f out fa l l and then an interaixiag or awel l spread out mixing tone where at the peripheri the temperature washardly above the ambient. The etretch of the aixing tone was about1 . 3 km along the bank and 0,3 ka off shore. As the Fig . 3 recorded8 ka/hr wind speed, the condition was a stagnancy in the lake . The lakestretched to about 3 ka in the off shore direot ion- and the theraallapaot was therefore f e l t only upto « tenth of available width, .

© 7 Theraal Water /ual i ty standards are generally se t round the following/ oriteria 7,9#

1, filling Zone- an area where water quality standards are netapplicable. This depends on the Halted spread of affectedregion as a saall fraction of the width at outfall.

V

2* Temperature standard - In cold climates a temperature maximumof 32-32.2°C i s recommended* at any time however the inoreasein temperature should not be greater than 2.5°C. in any partof the r irer system. In summer such increases shall be l e s sthan 1.1°C.

In conditions available in tropics namely, wide differences In diurnaland seasonal temperatures, and summer water temperatures at surfaceexceeding 35-38°C, the above cr i ter ia are not relevant. Except wherethe fishes get trapped or sedentary organisms are present* the impactof heated effluents i s not l ike ly to be f e l t on f i sh l i f e direct lyat a low power nuclear station s i t e s*

3 . Table 2 suggests that under the prevailing ciroumstanoes of designthe intake water drown from the hypolimnion and discharged to surface,there was an enhancement in i t s SO content in the process of circulationthrough the condenser. This effect i s demonstrated in the la s t fourcolumns of Table 2 . HighC.O.D. and B.O.D. of intake waters can becaused because of pollution ait depth(away from sunlight) and beoause tbelates contained rotting wood.

4* There i s a matted growth of Veileaneria grass in the outfal l regionwhich was found to be spreading and needed removal. This may not be •direct impact of thermal discharge.

INVESTIGATIONS CARRIED OUT AT S.S. LABORATORY(ESL)

Qam

Long hours of day light in tropical and subtropical regions can causealgal growth in stagnant reservoirs. Photosynthesis can lead to increase*oxygen output in waters. If heated effluents are also discharged* oxygensupersaturation can result because of elevated temperature. These effectswere studied in the SSL experimental tank as follows!

20*000 l i tres of raw water were transferred to a concrete tank of aise9.6 a x 5.2 a x 0.5 a. The waters were inoculated with culture of

and dosed with urea and other nutrients. "Measurements of SOpit and temperatures were made through out the duration of experiment*DO rose from 8.2 to 15 ppm and pH 8*9 to 11.1,, After 12 days exposurein sun and when the water appeared as a pea soup from algal growth*fingerlings of Indian carp (C .mrigala-Sj L.roMta-4) were introduced inthe tank. In a week's time 00 concentration exceeded 100JC over thesaturation limit, and the fishes progressively died* An examination ofdying fish showed that the fishes wer« breathing with difficulty andthe fish died from exoess of oxygen. Laceration of tissue la the g i l lregion was seen in the dead fish. . '

The outfall region cannot be treated as stagnant beoause of turbulencebut these observations are likely to be met with in tbe intermixing sone(Gas supersaturation) under tropical conditions. ttas bubbles were seen toescape from the tank wate* during the day (14.00 hrs).

t 5

Paraaitiaa

Two 'happas* (floating cages) war* fabricated froa nylon nettiaf builtaround a wooden frame 130 cm x 30 c« x 60ca. Tha happ*..? « n tiad looselyto fixed pegs on tha bank and ralaasad ona into tha discharge canal andtha otber(ooatrol) ia tb» lake upstream. Tha nylons cagea war© weightedto submerge partially so that tbt introduced fishss always raaainadunder haatad effluenta in tha 'test* o«ge, aa tha waters flowad throughthe net* Sach happa was charged with 20 nunbara aaoh of 0. oarpio,L.rohita and C. arigala. The exparinant had to ba glvin up as tba largef iahas ohawad away ohunka of aylong. * aat of iaprovisad cages waspraparad with ataal wirea and placed aa before* ia tb» diaoharga eanaland upatraaa aa Taat and Control respeotively. 90 fiiigarliags ofL.rohita eaoh wara plaoad in aaoh cage. Tha eagaa wax1* proridad with• l i t opaning in tba top cover for addition of flah fa««d and to oonduotperiodical axaeination* All tha fishas wara found dsud in a soothaararaly isaulad in bally and aouth.

Tha axpariaant was rapaatad with fingarlinga of L.rohita and C. a rigalwaighing thaa bafora placing thaa in tha oaga.

SnaaiaaL.rohita

Carigal

13

It

Piaataarga Canalv.Wt-g Langth-oa

238 2 6 ( « T )

ControlW

215210 26

Lengths ia

275 fingerlinga froa tba last and Control wara takaa </»ut for axaaination.L. rohita bad auffarad vary aavaraly in tha Test c«,«,» loaing nearly70g weight. Tba controls wore steady. C.arigala wosa also alailarlyaffected but not to tba saae extant. On closer Bcimtiny, tha fisheswara found to ba infested with aa Betoparasis identified as ilitropustypus. Tha parasite Aiitropus Typus i s a blood snaking type and i tattaeka the soft parts of the fish?.

Twin Aquaria •AaaeabliatuSwianraaia

The study of parasite proliferation, and synerg«als eaused by waste heat.as priaary polluntaat, are being oonduoted ia KSX* attached to nuclear s i t es .For this purpose two sets of aquaria experiaentsil tanks wars eleotronioallyconnected in such a way that tha water teaperature ia one ia 2,5*0 higharthan la the other waioh represents unaffected water of lake, upstreaa ofoutfall . The teaperature difference represents the peak teaperatureincreaae in the intexaixing sons* The expariaents under way are of twotypes, naaely, where . •<»••

I - Both the control and heated on* are ofeaxged with 5 fingerllnga and5 parasites(parasite behaviour and prolifration), and2m In addition to beat other pollutant* **• added to the oontrel aadtha Test aquaria e.g. 8J3, Cl9,Hg, Chrorates ate. to atudy syaergistlosffsots. • • * • - . - .

• /

TARAPUR ATOMIC POWER STATION

The Tarapur Atomic Power Station is 100 km north of Bombay on the VestCoast. The station output of 400 Mile is generated by two BWR units,The reactors are located on a promontory jutting out about 200 a intothe sea. The intake is, an open channel drawing waters from and uptoone fathon depth, the channel sloping into a stilling pool after asilt trap. The intake waters are about 1°C less than the ambient seawater temperature. The condenser discharge which has a temperatureof 1O°C above the intake water, across the condenser ends, flows outto the sea through two disoharge canals-one north of and the othersouth of the intake?. Although originally intended to preventreoiroulation of heated effluents by directing the disoharge to followthe tidal flow at present the disoharge flows out of both the canals.The discharge canals are 14 • wide, 4 a deep and nearly one kilometerlong and do not oontribute to thermal abatement by themselves, exceptin high tides because of dilution and inteiaizing with on ruehingwaters.. During other periods the wind cooling takes place only to theextent of lowering by 1°C as the water reaches the end of the oanal.

Two important natural factors that help control thermal pollution arei) monsoon rains lasting for 3 months and strong breese, and ii)turbulence caused by semidiurnal tides which may rise upto 5-6 a, givingeffective mixing and dilution2*

There ia no evidence as yet to demonstrate the negative effeots ofthermal disch^ges at Tarapur. Even in the many sedentary speciespresent along the coastline and creeks, no accelerated growth ofvegetation or radioactivity uptake in fish have been observed. Thetemperatures of heated effluents drop suddenly by about 3°C, evenunder neap conditions, when the effluent stream meets the sea at thedischarge canal end in the first abatement step. Under low tideconditions about 400 a of the shelf are virtually bare and the effluentsflow over the exposed rooks. Thermal monitoring did not show anyincrease in temperature beyond t,3 ks from the disoharge oanal end.

WASTE HEAT UTILISATION

Studies on Waste Heat Utilisation have been initiated for sometime iaSSLs and it may taken sometime before effective techniques for wastebeat utilisation are developed for commercial exploitation.

At the Kaipakkam S S Laboratory, where the Madras Atomio Power Station1* located it is intended to use waste heat for large scale productionof algal oultares. An algal pond of sise 12 a x 9 » is in operationfrom last 3 y»ars using solar heat and domestio waste nutrients. Whenthe power station goes into operation, waste heat will ooae up as anadditional source of lowly rated heat flow. Mariculture is on theoards-particularly growth of shriape, prawns end lobsters*

Prawns font a aajor exchange earning induatry in the country .the different species Penaeua ipdicus and Pe^aa^s •onodon are widelyexployed for developing creek and estuarine fisheries. Experimentsare being initiated in cooperation vitb Tanilnadu aarioulture teaaafor setting up experimental assemblies in the discharge canals atTarapur for production of Prawns and Lobsters. Laboratory study i salso being planed at the Bajaethan - 8 S Laboratory for production offresh water prawns-type M.rosenbergii*

Acknowledgments* The authors desire to acknowledge assistance froaseveral colleagues and particularly of Mr. K.V.K. Nair(ESLJCalpakksa)Mr. B«Subs(BSUBajasthaa) and Shri 3 . Chandrtaouli(B3L-Tarapttr}. Theauthors gratefully acknowledge support received froa Dr. A.K, OangulytOireotor. Chcaioal Group and Mr. 3,0. 3oaan» Head, H.P.Oivisloa»BiR0«

( 8

BfiFfiRENCES

1 . Kamath, P.R., 'Environmental Surveillance at Nuclear S i t e s in India',NUCLEAR INDIA April-May 1978 (Publt DAB, Bombay-400 001) .

2 . Kamath, P.R., Bhat, I . S . , Gurg, R.P., Adiga, B.fl. and S.Chandramouli.'Seasonal Features of Thermal Abatement of Shoreline Discharge atNuolear S i tes ' presented at the IASA Symposium on .EnvironmentalEffects of Cooling Systems at Nuclear Power Plants:OSLO 26-50 Aug. 1974.

3 . Kanath, P.R., Bhat, I . S . and Ganguly, A.K. 'Environmental Behaviourof discharged Radioactive Effluents At Tarapur Atomic Power Station*IAEAJJSAflC Symposium on Environmental Aspects of Nuolear PowerStations; 10-14 Aug. 1970 N.Y., USA.

4 . Crurg, R.P., Bhat* I .S , and Kamath, P.R.- Progress report of SSLRejasthan Atomic Power Station . BARC report No. 1-369, 1975.

5 . Quxg, R.P., Bhat, I .S . and Ksmath, P.R. 'Thermal Pollution fromNuclear Power Production under Tropioal Conditions' Presented atthe symposium on Operating Experience of Nuolear Reactors sadPower Plants . Feb. 7-9, 1977 Bombay, DAE.

6 . Kamatb, P.R., Gurg, R.P., Sebastian, T.A., Vyas, P.V., Sub*, Band Nair, K.Y.K.'Impact on water qual i ty from Discharge of ThermalEffluents in RPS Lake' Presented at the IAEA Research CoordinationMeeting on Thermal Pollution, Kalpakkam, Dec. 5-9, 1977.

7* Miller* D.C. and Beok, A.A. 'Development and Application of Criteriafor Marine Cooling Waters' Paper IAEA-SU_187/1O in Symposiummentioned in Ref. 2 above.

8 . Je ter , C. 'An Approach to Thermal Water Quality Standards' Presentedat the Conference on Taste Heat Management and Ut i l i sa t ion , 9*11 May1976, Miami Beach, Florida, University of Miami.

9 . Chaudhary, R.S. and Walker, M.F. 'Parasitic Behaviour of FreshWater ISOPODEALITRpPUS TYPUS in f ishes of Rana Pratap Sagar India1

(In press) 1978. Preprint communicated.

1 0 . Fishes and Fisheries - publication of CSIR, New Delhi 1962Supplement to 'The Wealth of India* Vol. IV.

EAJA3THAN: SEASONAL VARIATION IN AMBIBMTAND COOLiaS .TEMPERATURES

nnmnsanSat*and t i n *(bra)

26.2.74(11.00)

9.3.74(11.10)

18.3.74(14.30)

10.4.74(15.30)

25.4.74(13.00)

20.5.74(15.30)

25.5.74(10.30)

1.6.74(11.30)

5.6.74(17.15)

13.6.74(10.30)

27.6.74(14.10)

PowerHV

130

155

150

170

170

175

150

180

160

175

125

Anbitnt

Air

23.6

32.2

32.5

36.5

37.0

39.3

35.0

35.0

36.0

35.5

38.8

temp. °CLaic*surface

23.5

26.0

24.7

29.2

28.5

31.7

30.0

30.0

30.0

31.0

29.7

Coolaatintake

•0

18.2

17.2

18.1

19.2

19.6

19.0

21.5

24.0

26.0

23.0

27.5

Coolantoutlet

•0

22.5

22.4

24.2

28.$

27.8

30.0

32.0

36.0

37.0

35.0

29.7

Tabl> - 2

COOLANT WATER QUALITY AT RAPS

Dat*

30.6.76

11.8.76

27.8.76

25.9.76

6.10.76

3.11.76

EeaotorPow«rMW«

165

170

172

160

180

11.11.76 175

Temp,differ-oncedt °C

10.5

11.0

2.0

10.5

10.5

8.0

11.0

Dissolved•xygan ppapercentsaturation

Int-tsk»

92.1

91.0

76.9

83.5

75.6

85.0

72.8

105.5

110.8

81.6

100.0

92.4

95.7

101.5

C.O.D.iat»k«

B.O.D.Xntak*.

+ 1,2

4- 0

+ 0.3

+ 0.7

+ 2.0

+ 1.1

+ 0.3

+ 1.2

• 0.5

+ 1.1

+ 0.5

+ 1.5

+ 0.9

+ 0.3

THERMAL ZONE OF RAPS OISCHARGE M8-1-77)

POWER LEVELCONDENSER INTAKECONDENSER OISCHARGE-28CAMBIENT TEMP.WIND SPEEDWIND OlRECKON SE

T7O MWe18°C-28 C2«C

8Km|Hr

PLUME DEPTHATATATAT

ABC0

: 3 0 M:1-5-M'1-0 M-<0SM

DISCHARGEPOINT

200 400DISTANCE ALONG

COOSHORE (METER)

1000

M • , •» o <o £* jp jrm n,' m ct r> «•> «i> n

1SW 3/»0flV SH313N NI HOUVA313 35iV1