pa" NUREG 75/087+ o

f * )g U.S. NUCLEAR REGULATORY COMMISSION

P~ ! STANDARD REVIEW PLAN\ '...../ OFFICE OF NUCLEAR REACTOR REGULATION*

SECTION 2.4.13 GROUNCWATER

REVIEW RESPONSIBILITIES

Primary - Hydrology-Meteorology Remch (HMB)

Secondary - Ef fluent Treatment Systems Branch (ETSB)

I. AREAS OF REVIEW

Data presented in the applicant's safety analysis report (SAR) on local and regional ground-water reservoirs are reviewed to Establish the ef fects of groundwater ou plant foundationsOther ar eas revie- 1 under this plan include identification of the aquifers and the typeof onsite groundwater use, the sources of recharge, present and future withdrawals, anevaluation of accident ef fects, c.onitoring and protection requirements, and design basesfor groundwater levels and hydrodynamic ef fects of groundwater on safety-related structuresand components. Flow rates, travel time, gradients, other properties pertaininq to the

novement of accidental contamination, and groundwater levels beneath the site are reviewed,as are seasonal and Climatic fluctuations. Or those caused by man, that have the potentialfor long-term changes in the local groundwater regime. ETSB will provide accioent scenarios

for HE5 staff use in evaluating accidental spills.

II. ACCEPTANEE CRITERIA

9 for SAR Section 2.4.13.1 : A full, documented description of regional and local groundwateraquifers, sources, and sinks is required. In addition, the type of qroundwater use,wells, pump 6nd storage fu;ilities, and the flow requirennts of the plant must be de-scribed. If qroundwater is to be used as an essential source of water for safety-relatedequipment, the design basis for protection frun natural and accident pher mena must comparewith Regulatory Guide 1.27 guidelines. Basts and sources of data must 2equately

described.

For SAR 2.4.13.2: A de urn tion of present and projected local and renional groundwateruse must be prcvided. Existino uses, including amounts, water levels, location, d, awdown,and sourte aqui*ers must be discussed and should be tabulated. Flow directions, gra-

dients, velocities, water levels, and ef fects of potent %l future use on these parameters,

including any possibility for revcrsing the directior of groundwater flow, must be indi-

cated. Any potential groundwater recharga area within the influence of the plant and

ef fects of constru;tien, including dewaterinq, must be identified. The influence of

existinq and potential future wells with respect to groundwater beneath the site must also

t.e discussed. Bases and * Jrces of data Fust be described and referenced.

-

UKNRC STANDARD REVlf W PLANsi d d ,i

- . .w ,

,.4 e., ( ..i e. .e es. oevie. .e m.ee n et., n . ti . v e 4m4. v tn. . .e . .,1,t 2.d r 7e(.,. 16 doe, . ..d. .n f. ta. ,,,.= . .t . C.-- . u , t. .. . . .w % ., 4."J J.dm ., .d.. d o s. d.a , , .. .,. e., .,,

f..e,84.or.,w$th 19b, rut 1. re.t r.ggel d Ib. .t.rt..,4,.M.Wr ,4

rtl.8t. b.Y.d t. A 4 6 I .f th. St d d Fd ., C . . d

m.t d C q t .f $.foty A m.8y.A R maa.f., Ngate , .w.e Pl t. Not ctt.ft. .f th. At.rtd.,4 I t.1 h . ..,' 4dletg . 4.up pl

9Fh008h.d .T.''d.rd 0.W .0 W1. be l..d p rt.dic.f L .ppe. pet.g. td, .cc.mset.d.t. e. muse.evt. . rid gg y.fl.ct ,i.uy ip - .rs 96 .e, i u p.ee. roc.

C == t. .ad ee t f., h.,r.v.m t wm b. e d. red d .h ed b. t t. th. U a h co e m.o.6.e ,ry Commi e o,A. .e mura , n. 4.,R.w.e.e* . vW hi O C Fme-

Rev. I70071200 %

For SAR 5ection 2. 4.13. 3: Radionuclide transport characteristics of the groundwater q

environr:ent with respect to existing ana future users must be described for both operating

and accic'ent conditions Estimates and bases for coefficients of dispersion, adsorption,

groundwater velocities, travel tines,1radients, perreabilities, porosities, and ground-

water or pietometric levels between the site and existing or future surface and ground-

water users must be described and be consistent with site characteristics Potentialpathwy s of contamination to groundwater users must also be identi fied. Sources of data

must be described and referenced. One- or two-dinensional nathematical nodels are accept-

able to analyze the flow field and convective dispersion of contaminants in surf ace waters,providinq that the models have be7n verified by fiald data and that conservative site-

specific hydrologic paraneters are used. Furthermore, conservatism must be the guido in

telecting the aroper model to represent a specific physical situation. Radioactive decay

and sediment adsorption may be considered, if applicable, providinq that the aJsorptioa

f actors are conservative and site-specific.

For SAR Section 2.4.13.4: The need for and extent of procedures and measures to prt tect

present and projected groundwater users, including monitoring proqran>, must be discussed. |

These item, are site-specific and will vary with each application.

for SAR Sectior 2.4.13.5: The design bases (and develnent thereof) for groundwater-induced loadings on subsurface portions of safety-relmed structures systems, and corpo-

nents must be described. If a permanent dewatering system is erployed to lower designbasis groundmater levels, the bases for the design of the systen and determination of the

design basis for groundwater levels c.ust be provided. Informatinn must be provided r egard-inq (a) all structures, cceponents, and features of the systen, (b) the reliability of the

syst: as related to available perf ennance data for similar syster s used at other locations,

(c) the various soil parameters (,uch as pen cability, porosity, and specific yield) used

in design of the system, (d) the bases for determination of groundwater flow rates an'1areas of influence to be espected. (c) the bases for deternination of time available to

nitigate toe consequences of system f ailure where system f ailure could cause design basesto be esteeded. (f) the effects of malfunctions or failures (such as a single failure of a

critical active component or f ailure of circulating water system piping) on systen capacityand subsequent groundwater levels, and (g) a description of the proposed groundwater levelmonitnring program and outlet flow conitoring prograr Specific criteria relatinq to the

design of permnent dewatering systems are presented in the attach"d Branch Technical PositionjHMB/G5B 1 " Safety-Rela ted Pernanent Dewa tering Sys tems" In addition, if wells are proposed I

for safety-related purposes, the hydrodynamic design bases (and development thereof) forprotection against seismically-induced pressure waves must t'e described and be c >nsistentwith site charicteristics

III. REVILW PROC [Dl!Rf 5

Section 2.4.13 of the applicant's SAR is reviewed to identify any missinq data, i n f orni t i on ,

or analyses necessary for the staff's evaluation. Applicant responses to the requested

information will be tvaluated using the methods outlined below; and staff positions will bedeveloped based on the results of the analysis. Resolution, if possible, of potential

groundwater problems or c f dif ferences between applicant's and sta f f's design nases, will? ff C1 I, (. J. d| tJ

Rev. I 2.4.13-2

|be coordinated through the LPM, and the SER will be written accordingly. The review

sequence is shown in f igure 2.4.13.

Local and regional groundwater conditions are reviewed b/ comparing the applicant's descrip-tion with reports by the U. 5. Geological Survey (USGS), other agencies, and professionalorganizations. Other NRC organizational elew nts with related review responsibilities |

will be notified of any applicable groundwater data and analyses If unsite groundwiter

u .e and f acilities are safet/-related, the criteria of Regulatory Guide 1.2/ are applied.

The staf f will cumpare the applicant's description of present and projected local andreginnal groundwater use, existing users, including achient use, water levels, location,and drawdown wi th information and data f rom ref erences Drawdown ef fects of projected

f u tur. groundwater use, including the possibility for re ersing the groandwater flow, w 11be evaluated and way be checked by independent calculations. Construction effects, includ-inq dcwatering, on potential recharge areas may also be evaluated.

The staf f will make independent calculations of the transport ceabilities and potentialcontamination pathways of the groundanter environment under accid % tal conditions withrespect to cristing and future users Special attention stluld be diretted to proposed

facilities with permanent dowatering systems to assure that pathways create _d by thosesystems have been identified. The staff will, in cu sultation with the Effluent Treatment

Systems Branch (ETSB), choose the accident scenarios leading to the mcst adverse contamina-tion of the groundwater or to surface water via the groundwater pathways. Analysis of the

6% cuntamination will com nce with the simplest mudels, such as ' hose presented inPeferences 22 and 23, using demonst atably conservative assumptions and coefficientsDilutions and travel times (or il ternat ively, concentrations directly) resul ting f r nm thepreliminary analyses will then be checked by ETSB to determine acceptability. If theindicated concentrations of radionuclides, identified by ETSB, are less thun 10 CFRpart 20, part B, no further computational efforts will be wirranted. Further analysesusing progressively more realistic and less conservative modeling techniques, such as thoseof Fef erences 9 and 26, will t,e undertaken if the preliminary results arr not acc"ptable.The needs and plans for procedures, measures, and monitorir-g proqrams will be reviewedbased upon site-specific qroundwater featurec. Design bases for groundwater-induced load-ings on subsurface portions of safety-related structure + are reviewed. Independent tal-culations are perforud to determiw the adequacy of the design criteria and the capabilityto reflect any potential future changes which can be induced by variations in precipita-tion, construction of future wells and reservoirs, accidents, pipe failures, or othernatural events. f'or dewatering systems, calculations are performed to determine phreaticsurfaces, rorwal flow rates, flow rates into the system as a result of pipe breaks (cir-culating and service water system pipes), groundwater rebound tire assuming total failureof the systen, and system capacity.

The above reviews are perforr"ed only when applicable to the site or site region. Sone') p ij1,

iter"s of review nay be done on a generic basis.-

2.4.13-3 Rev. I

IV. EVALUATION FINDINGS

Jr construction permit (CP) reviews, the findinqs will sumarize the applicant's andstaff's estirates of groundwater levels associated with safety-related structures, andwhere applicable, groundwater flow directions, gradients, velocities, effects of potentialfuture use on these parameters, applicability and reliability of dewaterinq systems, andthe ef fects of an accidental release of radioactive liquid ef fluent on existing and 'uture

users. If the desian bases estimates are comparable, staff concurrenco m tne applicant's !estinates will be stated. If the staf f predicts substantially more conservative ground-

water conditions and the proposed plant nay be adversely affected, a statement of thesta f f bases will be r ade, if groundwater conditions do not constitute design bases, thefindings will so indicate.

For operatinq license (OL) reviews of plants that have had detailed qroundwater reviews atthe CP staqe, the CP conclusions will be referenced. In addition, a review of qroundwaterhistory since the CP review will be indicated and note of any changes in qroundwaterconditions or usaqe will be made, for pernanent dewatering systers, any additional infor-mation reqarding soil proper *ies and groundwater conditions cathered during constructionwill be evaluated to determine the applicability of the assumed CP design basis If no

CP groundwater review was undertaken, of the s'. ope indicated above, this fact will be

noted in the CL findings in addition to the results of the current review.i

A samle CP statement follows:" Groundwater is available at the site in low to noderate yields from the followinq

four n uifers listed by increasinq depth below the surface: (1) tFe unconfinedwatertable aquifer consisting of the A and B formations, (2) the confined C-Upper Daquifer, (3) the confined upper D aquifer, and (4) the confined riddle D aquifer.Groundwater in the A-B town aquifer generally moves toward the local streams, whereas,in the deeper confined aquifers, groundwater generally moves toward centers of pump-inq. At tne present, saltwater intrusi0n into the aquifers at the site is notevident as a result of brackish water mov' from the E Bay, the F Canci, or G Bay.

"The applicant plans to use groundwater during plant operation at a continuous rateof 140 gpm, of which 100 apm will be used for d s ineralized water requirerents, and40 qan will be service water for drinking, washing, and filling the fire protectionstoray tanks The source of this supply will probably be the A D aquifer, for whichthe applicant has conducted pumping tests at two locations The applicant has indi-

cated he may utilize another deeper aquifer for this supply, an i has aqreed to supplyadditional pumping test data to the staff for evaluation if another aquifer is chosen.This is acceptable to the staff.

" Precipitation is the source for groundwater recharp to the A-B aquifer. The rcchargearea for this aquifer lies to the southwest of the plant site and extends beyond theCity of M. No major recharge areas for the lower confined aquifers are believed toexist in the vicinity of the site.

j AE p ..J UJ[Rev. 1 2.4.13-4

"A water-table design level of 65 feet MSL (15 feet below plant grade) v.as selected bythe applicant to determine hydrostatic loadings on safety-relatea structures. T ',estaff concurs that this level is conservative sir:e the highest measured water taDie

elevation at the plant site following an extremely rainy season was 63.4 feet MSL.

"The staf f postulated an instantaneous rupture of the baron recycle tank veith no con-tainment by plant structures as b9ing the design basis event for contamination of

groundwater and surface water. The travel time to the nearest groundwater user was

conservatively estimated to be a minimum of 29 years with a dilution of at least

6000. The resultant concentrations were found to be less than 10 CFR Part 20 B.'

V. REFERENCES

In addition to the following, references on methods and techniques of analysis, published

data by Federal and State agencies, such as USGS water supply papers, wil.1 be used asavailable.

1. J. D. Bredehoef t and G. F. Pir. der, " Digital Analysis rf Areal Flow in MultiaquiferGroundwater Systems : A Quasi Thr"e-Dimensional Model," Water Resources Research,Vol. 6, No. 3, pp. 883-888 (1970).

2 " Finite Element Solution of Steady State Potential flow Problems,' HEC 723-G2-L2440.

Corps of Engineers (1970).

3. T. A. Prickett and C. G. Lonnquist, " Selected Digital Computer Techniques for Ground-water Resource Evaluation," Bulletin 55 Illinois State Mter Survey, Urbana, Illinuis

(1970).

4 D. B. Cearlock and A. L. Reisenauer, "Sitewide Groundwater flow Studies for Brookhaven

National Laboratory, Upton, Long Island, New York," Battelle Pacific Northwest Labor-

atories, Richland, Washington (1971).

5. K. L. Kipp, D. B. Cearlock, A. L. Reisenauer, and C. A. Bryan, " Variable Thickness

Transient Groundwater flow Model--Theory and Numerical Implementation," BNWL-1703,

Battelle Pacific Northwest Laboratories, Richland, Washington (1972'.

6. D. R. Friedrichs, "Information Storage and Retrieval System for Well Hydrograph P3ta--User's Manal," BY.JL-1705, 3attelle Pacific Northwest Laboratories, Richland,

Washington (1972).

7. K. L. Kipp and D. B. Cearlock, "The Trant nissivity Iterative Calculation Routine -

Theory and Numerical Implementation," BNWL-1706, Battelle Pacific Northwest Labora-tories, Richland, Washington (1972).

8. S. W. Ahlstrom, R. J. Serne, R. C. Routson, and O. B. Cearlock, " Methods for Estimat-ing Transport Model Parameters for Peqional Groundwater Systems," BNWL-1717, Battelle,p-Pacific Northwest Laboratories, Richland, Washington (1972). ) q, 7] jj)

2.4.13-5 Rev. I

9. R. C. Routson and R. J. Serne, "One-Dimensional f% del of the Movement of Trace Radio-

active Solutes Through Soil Columns f he PERCOL Model," BNWL-1718, Battelle Pacific

Northwest Latoratories, Pichland, Washington (1972).

10. R. C. Routson and R. J. Serne, "Experimen+.al Support Studies for the PERCO'_ and

Transport Models," BNWL-1719, Battelle Pacific Northwest Laboratories, Richland,Washington (1972).

11. K. L. Kipp, D. B. Cearlock, and A. E. Reisenauer, " Mathematical Modeling cf a Large,Transient, Unconfined Aquifer with a Heterogeneous Perneability Distribution," Paperpresented at the 54th Annual Meeting of the American Geophysical Union, Washington,

D. C., April 1973.

12. L. L. Schreiber, A. E. Reiv nauer, K. L. Kipp, and R. T . Jaske, "Articipated Effectsof an Unlined Brackish-Water Canal on a Confined Multiple-Aquifer 5ystes ," BNWL-1800,Battelle Pacific Northwest Laboratories, Richland, Washington (1973).

13. Regulatory Guide 1.27 " Ultimate Heat Sink. '

14 W. H. Li and F. H. Lai, " Experiments on Lateral Dispersion in Porous Media," Jour.Hydraulics Division, Proc. Am. Soc. Civil Enqinees s , Vol . 92, No. HY6 (1966) .

15. W. H. Li and G. T. Yeh, " Dispersion of Miscible liquids in a Soil, Water ResourcesResearch, Vol . 4, pp. 369-377 (1968).

16. D. R. F. Harleman, P, F. Mehlhorn, and R. R. Rumer, "Dispersio '-Permeability Correla-tion in Porous Media," Jour. Hydraulics Division, Proc. Am. Soc. Civil Engineers,Vol. 89, No. HY2, pp. 67-85 (1963).

17. L. E. Addison, D. R. Freidrichs, and K. L Kipp, "The Transmissivity Iterative Programson the LDP-9 "omputer-- A Nan-Machine Ieteractive Systm," CNWl.-1707, Battelle PacificNorthwest Labvatories, Richland, Washinqton (1972).

IP, "'u< wentals of Transport Phenomena in Porous Media," International Association for

Hyc.c? > Research, Elsevier Publishing Company, New York (1972).

19. D. K. It 'id, " Groundwater Hydroloqy," John Wiley & Sons, Inc. , New York (1959) .

20. J. Bear, "Dyramics of Fluids in Porous Media " American Elsevier Publishing Company, ||

N u York (1972).

-1 NRC Hydrologic Engineering Section, " Dispersion Work book" (in prepara t ior.) .

22. R. Codell and D, Schreiber, "NRC Models for Evaluating the Transport of Rariinnuclides

in Groundwater," Proceedings of S r posium on Management of low-Level Radioactive

Wastes, May 1977, Georgia Institute of Technoloqy, Atlanta, Georgia (in preparation).

Rev. 1 2.4.13-6 , .

J)

23. F. A. Appel and v. D. Bredehoeft, " Status of Groundwater Modeling in the U.S.Geological Surves,' USGS Circular 737 (1976).

24. feerican Nuclear Society, "5tandards for Evaluating Radionuclide Transport in Ground-water, Draft 2."

25. J. O. Dugruid and M. Reeves, " Material Transport Through Porous Media: A FiniteElement Galerkin Model," ORNL-4928, Oak Ridge National Laboratory, EnvironmentalScience Division, Publication 733, March 1976.

26. R. L. Taylor and C. C. Brown, " Darcy's Flow Solutions with a Free Surface," Journalof the Hydraulics Jivision, ASCE, Vol. 93, No. HY2, pp. 25-33, March 1967

27. S. P. Nciman and P. A. Witherspoon, " Finite flerent Method of Ana'yzing Steady 5eepagewith a Free Surface," Water Resources Research, Vol. 6, No. 3, pp. 889-897, June 1970.

28. S. P. Neuman and P. A. Witherspoon, " Analysis of Nonsteady Flow with a f ree SurfaceUsing the Finite Element Method," Water Resources Research, Vol. 7, No. 3, pp. 661-623,June 1971

29. G. F. Pinder and E. O. Frind. " Application of Galerkin's Procedure to "muifer

Analysis," Water Resources Research, Vol. 8, No. 1, pp. 103-120, February 1972.

30. J. Rubin and R. V. James, " Dispersion- Af fected Transport of Reacting Solutes inSaturated Porous Media: Galerkin Method Applied to Equilibrium-Controlled Exchange inUnidirectional Steady Water Flow," V'ter Resources Pesearch, Vol. 9, Na. 5, pp. 1337-1356, Oc tober 1973.

31. L. O. Frind and G. F. Pinder, "Galerkin Solution of the Inverse Problem for Aquifer |Transmissivity,' Water Resources Research, Vol. 9, No. 5, pp. 1397-1410, October 1973. I

1

32. G. F. Pinder, ' A Galerkin-f inite Element Simulation of Groundwater Contanination onLong Island, New York," Water Resources Research, Vol. 9, No. 6, pp. 1657-1669,December 1973.

33. M. Reeves and J. O. Duguid, " Water Movecent Through Saturated-Unsaturattd Porous

Media: A Finite Element-Galerkin Model," ORNL-4127, Oak Ridge National Laboratcry,Oak Ridge, Tennessee, February 1975.

1i

34. Branch Technical Position HMB/GSB 1, " Safety-Related F entanent Dewatering Systems",attached to this section.

\h) . )

2.4.13 7 Rev. 1

F W.IIRE 2 413

ST ANDARD REvtf W PL AN SECTION 2 4 T3GROUNDW A T I R

LOC AT E SITE WITH R E %PI C T TO MA JL)H AND MINOH AOlllF F HS

f M T AIN AND R E Vtf W ANY ACCE PT f D USGS OH OTHE R F f DE R AL AN'3 ST A TE AGE NCY GPOllNOW A T[R H E POR TS F OR T HE Rf GION

Df T E R MINE COMPL F 'E NE SS OF APPL. lC AN T S S AR ST C T H)N 2 411*

*M PHOV'D F D A T A T O O T HF H H R A NC HE S -] H E VIE W T YPF OF PL ANT C hot PNOW A T f 4 USEF Artl ITIF S ANO t t OW Hf OtHRF MF N T4

'NO IS GROllNDW Aif H TO Hf U$f D AS A SAF F T V H E L Alf D W A if H SilPPL Y'

q D(I D E SIGN H ASE S PHOV ID E Alll Ot J A l f PH(li t C l ie)N F H UM[ N ") ~+ ACCIDE N T AL AND N A T U58 Al PHE NOME N A AND COMPL Y

\ WiiH HF G GIMDE T 21)

YI'| AR E O f SeG N H ASE $ F Dal GHol>NOW A T f R L t''t S ".SSOC l A T E D W I T H S A F F T Y H F l A T f D 5i Al6C T tlH I S PROV tD E D ' h

[ l IS AN AUE OUA f f DE SCH tP T HIN OF PHf SE N T AN't Pht)1! C T Fb A L ANI) Hi t:l()N A L GH ')t int 7W A I E H YES'- Il%F PHOVIDF n INrt lentNG l Kf H t AMOilN7% W A T F R t F Vg ' A f SON A NO D H AWOOW N '

- AH E PO f f N il A L R f CH AHG E AH f AS WIT HIN T HE INF L UE NC f OF T H E Pt. A N T li'f N TIF lf (.)' | YES

ENO-,

YISART C()NS TRifC TION E F f f f T S INCLtIDING DE W A T E H.N6 O f N f!Tif D' sy

N [ AH E D A T A SOURCf 5 AND R ASf $ DE NCHIRID ANO R f F f HINCE 0 7 YFST

[_~ " ' ^"' "'* ' G A ND AC C ID F N T C OND t ilO N'S' W I T H H F 5Pf C T T O F IL IS'i lN' ""A ND' ~F t J T i eH F I K f H % *' ' ' " ~ ^ ~ " " ' ' ' ' ' " > ~ ^ " ' " " ' ' ' " ' ' " ' " ' " " " ' " '' v'"''~"'~''v^'"'"""~"'" ' Y''

t)Pf M A TIN G | -

' 'AR E PO f f N i f AL CON T AMIN A TION PA T HP' A Y S T f) GHOIINt)W A T f H tlSE NS ID E N T IF li n ' *FS, ,

T

| AH f. O A T A $4 IllHC f $ A ND R A %f S D ( SCH IH I D A ND R Ii i R f NC 11) # | yFS

it THE NF f D f (SH MF A51fH F % Til PHe)if C i GHr.INOW A if H IISF H S Ol%Cl'S''D ' | VI5,-

AM F Pt ANS f DH PHO I E C TIV E ME ASilH F S AND Mr )NI Fim $NG PH(>GH AMS PHt)V IOf O' VIS, ,

f

A f ut if S T Mf SSINt, il A T A A ND A N A L V Sf S

I V Al I) A T E H f NPt sN5f SY

Y

i ilSI AN AL V ilC AL OR NUVF RIC AL Mf 8DE L S TO f v AL11A T F F L OW P A THS T H AN*.POR T OF ACCIDI NT AL L Y DISCHANGFDI R ADIONilCL IOE S Dl%PF RSION DlL U TION F L OW f1 A T E S GROtf NIiW A T F R L E Vi t $ AND DF W AT E RING SYS *E M C AP Afill lT V

C HE C II R E Sill T S WI T H F TSR

f ONCE N T R A T 80NS GR E A Tf R THAN PAR T 20 | CONCE NT H A TIONS ( E SS TH A N PAR i 20

-| CHE CIL CilN5f F4 V A f f SMS |

f t H) rONSF H V A l tV E !

H E A L 15 T 3C']t DUC E CONSF HV A T tsu !

E VI L ()F ST AF F ITISI T H rN

OTHFHHnAvHFSA i i f MP i 1 Q H ($1II V F

ME CH A NIC AL I NGINE ( RING RR ANCH iME HI Dif F E H F NF' S WIT H L PMS T Alr0 TUH AL F NGINF IHiNG Hn ANCH ISrtil A ND A PPL IC .N T

-

H ADIOL OGIC AL AS%F StME NT flR ANCH f R AM)(F F L tjf N T T F t A TMF N T SYST[MS liH ANCH (F TSdl

At CIDF N T ANAL YSli RH ANCH I A ARIAU W ll I A H Y S YS T F M4 H H ANrH i A gill

P( M F H S Y S T F M1 H H A NC H (P%ll!

'* APPL IC A N T PROVIOf D INF OHV A T lON IN SAR St C f tDN 2 4 i] 13 COMP ARI 3TO GillO ANr[ GIV( N IN SF ll,C DOCUMi N T 1R G , /01 TO Of I[ f4MINF COMPL E il NF SS

.

145 356Rev. 1 2.4.13-8

BRANCH TECHNICAL PgSITIONS HMB/GSB 1

SAFETY-RELATED PERMANENT DEWATERING SYSTEMS

1. Suma ry

This position has been fomulated to minimize review problens r.nmon to pemanent de.iater-ing systems that are depended upon to serve safety-related purposes by describinq accept-able geotechnit i and hydrologic engineering design bases and criteria. A safety-relateddesignaticn for pennanent dewatering systems is provided since they protect other safety-related structures, systems and components f rom the ef fects of natural and man caused eventssuch as groundwater. In addition, the level of documenution of data and studies which are

considered necessary to support safety-related functions is detined. This position applies

to both active (e.g. , uses pumps) and passive (e.g. , uses grav ty drains) dewateringsystems. This position does not reflect structural, mechanica: and electrical criteria.

II. Back round3The staf f has reviewed a number of pemanent dewatering system < , including McGuire 1 & 2,

Cherokee 1 & 2, Perkins 1 & 2, Perry 1 & 2, WFPSS 3 & 5, Deuglas Point 1 & 2, and Catawba 1& 2. Perry, beginning in 1975, was the first plant reviewed with such systems and wasreviewed very late in the CP process. Only WPPSS 3 & 5 and Deuglas Point use a passivesystm (no pumps).

Penaanent dewatering systems lower groundwater levels to redtce subsurface water loads

on plant structures. In addition, they can increase plant op trational dependabili ty andreduce costs. These effects are accomplished by providing added means of keeping seepagewater out of lower building levels during the later stages of plant life when normal water-proofing provisions r:ay have deteriorated, and reducing radwiste system operatirg costs byminimizing the amount of drait water that must be treated. l enefits are, therefore, of

two types, tangible (dollars) nd intangible (" insurance"). We understand the constructioncosts of underdrains can vary widely Jepending on the design. Construction costs of between$125K to $1000K per unit have been suggested. The costs of coping with significant amountsof groundwater inleakage in safety-related building areas, uhich underdrains are expectedto mini''ze, is estimated to be in the rjnge of $100K to $200K per year per reactor, lheconstruction costs of alternatives to underdrains for structur01 purposes alone (exclusiveof inleakage treatment) is estimated to range upward from $300K per unit and is highlydependent on site conditions. Struttural alternatives to termanent underdrains include

additional concrete and Steel in the lower portions of buildings, and the use of anchorsystems to resist floatation. . .-

\ th ',] ))!

Dewatering systems are generally composed of three compon?nts; the collector system, thedrain system, and the discharge systm. Water is first collected in collettor drains

2.4.13-9 Rev. I

adjatent to buildings or excavations. Interceptor drains or piping are then used to convey

this water to a final discharge system. The discharge system can be either gravity flowor a pumping system. Most underdrain structures, systems and components are buried along- .

side and under structures, althcugh some systems employ punping systems within largerstructures (such as reactor or auxiliary buildings) to discharge collected water. Finally,

permanent dewatering systens are not a required feature at any plant, but may be proposedas a cost effective feature.

Many permanent dewatering systems at ncnnuclear facilities, such as dars and large build-ings, have functioned over the years. However, the likelihood of a portion of such asystem tecoming ineffective and, therefore, not Ferforming its intended function ma)be considerably greater than the probacility of occurrence of a nuclear power plant cebasis event such as a Probable Maximum Hurricane, Probable Maximum Flood, or Safe Shutdown

Earthcuake. Losses of f unction in the past have generally been attributable to piping offines, inadequate capacity, or clogging. We have concluded that safety analyses of suchsystens should consider reliability and failures of features of the system itself, 3swell as potentially adverse ef fects of failures of nearby nonsafety-related featuresSuch systems need not be designed for design earthquakes if they are not intended to nerfornas underdrains fully during or irrediately following a severe earthquake, or if the systencan be expected to perform an underdrain function in a degraded condition. Certain portionsof such systems, however, may be required to regularly perform other safety functinns(e.g. , poreus concrete base mats) and should be designed for severe earthquakes. Failureof a dewatering system could canse groundwater levels to rise above design levels, resultingin overloading concrete walls and mats not designed to wi.nstand the resulting hydrostaticpressures. In addition to causing potential st uctural and equipment damage, groundwatercould enter safety-related buildings and flood components necessary for plant safety.

The basis for staff concerns over the use of such systens is whether they can be expected

to perform their function, and prevent structural failures and interior flooding of safety-related structures. The degree of concern is directly related to the corresponding degreeto which the safety of the structures and systems rely on the integrity of the dewatering

system, particularly with a Hewatering system in a degraded situation. For example, i fstructures can accorrodate hydrostatic, loads that would result with a total failure ofa dewatering system, our concerns have been primarily limited to the capability of suchsystems tc perforn their functions under relatively infrequent earthquake situations

,

i

If, however, such systems rust renain functional (e.g., keep water levels down), whether i

in a degraded situation or not to prevent structural failuras and internal flooding under II

potentially frequent conditions, we have been very concerned with system reliability. t

i

Many applicar,ts have indicated that their plants can withstand, or have been designedagainst, full hydrostatic loadings that would occur in the absence of the underdrain systems,but net if an earthquu e were to occur. If the plant can withstad full hydrostatic loading,

assuming degradation of the underdrain systen, rany of the staff's concerns nay beeliminated fron further consideration because of the time available for reredial actionafter detection of systen degradation.

2.4.13-10 } [I I *CO"V'a

}J f).)

Ill. Situations identified Durinciprevicus Reviews._

Four general categories of situations have been identified durinq case reviews as follows:

(a) Estima ting and Confirminr) Pcrmeability ValuesIt is necessary to es timate the amouat of water that will be collected 50 th2t systencomponents such as strip drains, blanket drains, collector pipes, and pumps are ade-quately designed ed sized. One of the most important and most dif ficult parametersto evaluate is the penneability of the soil and rock existing at a site. A per-meability value could be af f ected significantly by conditinns of concentrated ficwalong joints in fractured and weathered rocks, or within other aquifers af fected byfoundation extavation. In addition, geological and foundation conditions that were

not detected in site emplorations may affect flow conditions and cause the est matedpermeability values and flow regimes to be substantially dif ferent f rom those assumedat the CP preliminary design stage. These conditions are of ten first detected duringconstruction dewatering. Therefore, we have required a connitrent to consider con-struction excavation and dewatering data in the final design of underdrain systems.(See situation (d) t elow. )

(b) Operational Monitoring OcquirementsTo guard against system malfunctions and to assure sufficient time is available for

implementation of remedial measures before groundwater could rise to an unacceptablelevel, provisions must be made for earlv detection of system failures, and contingencymeasures for these failures must be well defined prior to plant operation. Sincedrain systens are usually buried and concealed and there may be no direct way ofinspecting then, reliance nust be placed on piezoneters, observation wells, manholes,and monitoring of collected water to detect problems or malfunctioning of the sy, ten.The details of an operational monitoring progrr are necessary prior to constructionof the undc~drcie. tu assure that e3ch if the following will be p avided: (a) an earlydetection alarm system during normal operatinq conditions; (b) regu kriv scheduledinspection and nonitoring; and (c) competent evaluation J obserations curing bothconstruction and operation. In addition, the bases for accep M ble contingency reas.ressuitable for coping vith various possible hazardo Fust be established at the C" stage.

(c) Pip _e B rea k s

A dewatering system might be everloaded by such conditions as 1" or breaks in

either the circulating or service water systems. A 1mk V break may t en

a very small percentaqe of the total flow of the cooling i, b# large

enough to exceed the hydraulic capacity of drains, pipes an. n the dewatering

system. For example, a complete failure of circulating W er fstem piping has beenrequired in the design of the dewatering sy tems re,iewed to date. This requirement

was made to assure that such abnormal occurrences do not adverseiy af fect the integ-rity of safety-related s tructures, 9 tens, and corponents.

9 (d) S_equence of Reviewf F ^4

r- ., 3,u

Underdrain systems are usually one of the first itens constructed and, h fe. back-filling and construction of subsurface facilities, are the- no longer visible for

2.4.13-11 Rev. I

regular inspection. In most cases, these systems are initially designed based on

rather limited information f rom preconstruction field activities, and are tailored

specifically for the site and facilities. By necessity then, final review and approval

by the staf f of the design must rely in some part on information gathered duringconstruction. Therefore, the review and approval Can be accomplished in two ways:(1) design details of the permanent underdrain system, the operational monitoring programand plans for constrxtion dewatering can be submitted in the PSAR, with only con-firmation of the details requircd prior to actual construction; or (2) concentual

designs of the permanent Aderdrain systen and the operational monitoring progranand Cetails of Construction dewatering can be submitted in the PSAR with the morecomplete review and approval based on construction dewatering requiring review anday rt al prior to actual construction. Review and approval of unique designs at

post-CP matters is based upon 10 CFR Part 50, Subsections 35(b) and 55(e)(1)(iii). Toprevent extending the review schedule, the first procedure would be the mostdesirable, but the staff recognizes that the detail required may not always be avail-able at the time the PSAR is submitted.

I

IV. Proposed Staff PositionWe have reviewed and opproved the design of a limited numter of permanent dewateringsystems. Howevcr, because of the importance of these systems to plant safety, we have

always required that they be designed and used in a conservative manner. The following is alist of requilei design provisions which are consistent with requirements in recent CP

reviews:

(a) if the dewatering system is relied upon for any safety-related function, the systemcust meet the appropriate criteria of Appendix A and Appendix B to 10 CFR Part 50.

In adJition, cuidance for structural, mechanical ar:d electrical design criteria is

provided in related sections of the Standard Review Plan for Category I structur es,

system and cor"ponents. However, all portions of the system need not be designed toar. corr:odate all design basis events, such as earthquakes and tornados, provided thatsuch events cannot either influenct. Lne system, or that the consequences of failure

from such events is not important to safety; nevertheless, a clear demonstration of

the effectiveness of a backup system and the timeliness of its implementation n.usi.be provided;

(b) the potential for localized pressures developing in areas which are not in contactwith the drainage system, or in areas where pipes enter or exit the structuralwalls or mat foundations, must be considered.

(c) uncertainty in detecting operational problems and providing a suitable monitoringsystem must be considered;

(d) the potential for piping fines and clogging of filter and drainage layers nust beconsidered;

G,<,r

}Q) 300

Rov 1 2.4.13-12

e& 4-

eg.f g .

,

,,. m ./ , , o,9\ [* ' ' '

e, v D ''

%y ,,,+

})yr JQsf ,j@p

s

"

*, _ . . _1, _

TEST TARG.T (MT-3)

1.0 5,'?"2 s

2 q2.2,.

[| 739 CsIc||s--0t r i,

I!!,,2,|,| =

UEI.25 IA

'

"\\ .6II, = = ===

* 6" >

'

h// 4 |Ab ''

w> s,/c

r<,:.

s , ;O ++

te

\

b. n ->,

&& loobg <;,p. ,y

+. c . .:- ,, r9 ,

hf* |I/2s ''

<> +- - .TEST TARGET (MT-3)

' l.0 1 ''* '2 4m n22

G[ pqE f fl )m2SI,I ; e.

NA$I l.25 W l.4 In|=i.6|--- it ---- il _=-

* - 6" >

& %,7%

sp *,4 ,,9*%

A %., / %//y ,s' ' 'k .'p e >, .. ..

4 .C p , ,- Q\.,

' "~ ?, .| ' ;, 0

_

0 : yp

(e) assurance must be provided that the system as proposed can be expected to reliablyperform its function during the lifetime of the plant; and

(f) where the system is safety-related, is not totally redundant or is not designed forall design basis events, provide the bases for a technical specification to assurethat in the event of system failure, necessary remedial action can be implementedbefore design basis conditions are exceeded.

V. SAR's (Std. Format & Content Information, Sections 2.4 & 2.b) for each of the plants withpermanent dewatering systems should include the following information:

(a) Provide a description of the proposed dewatering system, including drawings showingthe proposed locations of affected structures, components and features of the system.Provide information related to the geotechnical and hydrologic design of all systemcomponents such as interceptors, drainage blankets, and pervious fills with descrip-tions of material source, gradation limits, material properties, special construc-tion features, and placement and quality control measures. bote structural,

mechanical and electrical information needs described elsewhere.) Where the dewater-ing system is important to safety, provide a discussion of its expected functionalrel i a bil i ty. The discussion of the bases for reliability should include comparisonsof proposed systems and components with the performance of existing and comparable

systems and components for applications under site conditions similar to those proposed.Where such information is unavailable or unfavorable, or the application (designand/or site) is unique, the unusual feature of the design should be supported byadditional tests and analyses to demonstrate the conservative nature of the design.In such cases the staff will meet with the applicant, on request, to establish thebases for such additional tests and analysas.

(b) Provide estimates, and their bases, for soil and rock permeabilities, total porosity,effective porosity (specific yield), storage coefficient and other related parametersused in the design of the dewatering system. In general, these site parameters shouldbe determined utilizing field and, if necessary, laboratory tests of materialsrepresentative of the entire area of influence of the expected drawdown of the system.Unless it can be substantiated that aquifer materials are essentially homogerieous, orthat obviously conservative estimates have been used as design bases, prcvide pre-construction pumping tests and other in-situ tests performed to estimate the pertinenthydrologic parameters of the aquifer. Monitoring of pumping rates and flow patternsduring dewatering for the construction excavation is also necessary tc verify assumeddesign bases relating tu such factors as permeability and aquifer continuity. Inaddition, the final design of the system should be based on construction dewateringdata and related observations to assure that the values estimated from site explorationdata are conservative. Lastly, the final design of the dewatering system and itshydrologic and geotechnical ope.ational monitoring program should be confirmed byconstruction excavation and dewatering information.

146 001. ,

2.4.13-13 Rev. 1

If such information fails to support the conservatism of design information previouslyreviewed by the staff, the changed information should be reviewed under 10 CFRPart 50, Subsections 35(b) and 55(e)(1)(ii . ).

(c) Provide analyses and their bases for estimates of groundwater flow rates in the variousparts of the permanent dewatering system, the area of influence of drawdown, and theshapes of phreatic surfaces to be expected during operation of the syster. The extent

of influence of the draudown may be especially important if a natural or man-madewater body af fects, or is affected by, the dewatering systems.

(d) Pro..ue analyses, including their bases, to establish conservative estimates of the '

Itime available to mitigate the con, quences of system cegradation* that could cause j

groundwater levels to exceed design bases. Decument the measures that will be takento either repair the system, or provice an alternate dewatering system that wouldbecome operational before the design basis groundwater level is exceeded.

t

i

I(e) Provide both the design basis and normal operation groundwater levels for safety-related structures, systems and components. The design basis groundwater level isdefined as the maximum groundwater level used in the design analjsis for dynamic or i

static loading conditions (whichever is being considered), and may be in excess of ;

the elevation for wnicn the underdrain system is designed for norm 31 operation. This |level should consider abnormal and rare events (such as an occurrence of the SafeShutdown Earthquake (SSE), a failure of a circulating water system pipe, or a singlerailure within the system), which can cause f ailure or overloading of the permanentdewatering systes

(f) A single failure of a critical active feature or ccmponent must be postulated duringany design basis event. Unless it can be documented that the potential consequencesof the failure will not result in Regulatory Guides 1.26 and 1.29 dose guidelines

being exceeded, either (1) document by pertinent analyses that groundwater levelrecovery times are sufficient to allow other forms of dewatering to be implecentedbefore the design basis groundwater level is exceeded, discuss the neasures to beimplerented and equipment needed, and identify the amcunt of tipe required toacconplish each measure, or (2) design for all system components for all severenatural phenomena and events. For example, if the design basis groundwater levelcan be exceeded only as a result of a si l e nonseismically induced failure of anyl

component or feature of the systcia, the staff may allow the design basis level of thedewatering system to be exceeded for a short period of time (say 2 or 3 days), provided >

that (1) effective alternate dewatering means can be irplemented within this timeperiod, or that (2) it can be shown that Regulatory Guides 1.26 and 1.29 guidelineswill not be exceeded by groundwater induced impairnents of safety-related structures,systems, er components.

@*See (f) for considerations of differing system types.

146 002Rev. 1 2.4.13-14

(g) Where appropriate, docu:nent the bases which assure the ability of the systen to with- ,

stand variou3 natural and accidental phenorena such as earthquakes , tornadoes, surges,

floods, and a single f ailure of a cor ponent feature of the 'ystem (such as a failure'

of any cooling water pipes penetrating, or in close proximity to, the outside wallsof safety-related buildings where the groundwater level is controlled by the system) f

An analysis of the consequences of pipe ruptures on the proposed underdrain syste: !

"ust be provided, and should include considerations of postulated breaks in the |

Circulating systen pipes at, in , or nea r the dewa tering syster, t<uilding either irde-'

pendently of, or as a result of the SSE. Unless it can be doca; rented that the poten-tial consequences will not be serious enough to affect the safety of the plant to the f

extent that Regulatory Guides 1.26 and 1.29 guidelines could be exceeded, provideanalyses to docu:'ent that (1) water releasrd from the pipt; break cannot physically i

Ienter the dewatering system, or (2) if water enters the dewaterinq >yster , the systerw;11 not be overloaded by the increased flow such that the design basis groundwater !

level is subsequent h exceeded,i

(h) Stite the maximum groundwater level the plant structures can tolerate under varioussignific3nt loading conditions in the absence of the underdrain syster

!

(i) >rovide a description of the proposed groundwater level conitoring programs f or ,

!

dewatering during plant construction and for permanent dewat aring during plant opera- }

tien. Monitoring ;nforration re v ested includes (1) the general arrangemnt in planand profile with approximate ele ntico of piezoreters and observation wells to beinstalled, (2) intended zone (s) of placerent, (3) ty; a(s) of oiezoreter (closed or opensystem),(4) streens and filter gradation descriptions , (5) crawings showing typical ;

tinstallations showing limits of filtur and seals, (6) observation schedules (initialand ti:re intervals f or sJbsequent readin]s), (7) plans for evaluation e recorded eata. ,

and (8) plans for dlarn devices to assure sufficient tir-e f or initiation of Correctiveaction. Provide a co:ritrent to Case the fin 3l design of the operational ronitoring ;

program on data gathered during the construction ronitoring program (if constructionexperience shews the assucPd operational program bases to be nor ccnser /ative orimpractical). Changes to the operational progra~ are to be documented in the FSAR.

|

(k) Provide information regarding the atlet flew nonitoring program. The infornationrequired includes (1) the general location and type of flow reasure m nt device (s),and (2) the observation plan and alarn precedure to identify unanticipated high or i

low flow in the system and the condition of *.he ef fluent. !

i

!

f(1) For Ob reviews, but only if not previously roiewed by the staf f, provide (1) sub -stantiation of assumed design bases using information gathered dur.ng de<.atering f orconstruction excavation, and (2) all other details of the dewatering systen design i

that implement design bases established during the CP review.

(m) For OL reviews, provide a Technical Specification for periods when the dewateringsystem raay te exposed to sources of water not considered in the design. An exampleof such a situation would be the excavation of surface seal raterial for repair of

2.4.13-15 Rev. 1

146 003

piping such that the underdrain would be exposed to direct surface runoff. In addi-

tion, where the permanent dewatering systen is safety related, is not corpletely

redundant, or is not designed for all design basis events, provide the bases for a

technical specification with action levels, the remedial work required and the esti-

nated time that it will take to accornplish the work, the sources, types of equipment

and mar ower required and the availability of the above under potentially adve-se

conc [See Section V(f)].

O

@

146 004Rev. 1 2.4.13-16