ML17255A744

Proposed Tech Specs Increasing Storage Capacity of Spent Fuel Pool Storage Racks

ML17255A744
Person / Time
Site:	Ginna
Issue date:	04/02/1984
From:	ROCHESTER GAS & ELECTRIC CORP.
To:
Shared Package
ML17255A742	List: ML17255A741 ML17255A743 ML17255A744
References
NUDOCS 8404100124
Download: ML17255A744 (145)

Text

'ttachment AReplacepage5.4-1withattached5.4-1through5.4-5.8404i001Z4 840402PDRADOCK05000244PPDR II1'-iiI'V.

FuelStoraeSecification Thenewandspentfuelpit.structures aredesignedtowithstand theanticipated earthquake loadingsasClassIstructures.

Thespentfuelpit,hasastainless steellinertoensureagainstlossofwater.ThespentfuelstorageracksaredividedintotworegionsasdepictedonFigure5.4-1.InRegion1itisimpossible toinsertfuelassemblies inotherthanthe.prescribed locations.

Thefuelisstoredvertically inanarraywithsufficient centertocenterdistancebetweenassemblies toassureKeff<0.95for(1)unirradiated fuelassemblies delivered priortoJanuary1,1984(Region1-15)containing nomorethan39.0gmsU-235peraxialcm,and(2)unirradiated fuelassemblies delivered afterJanuary1,1984containing nomorethan41.9gmsU-235peraxialcm.InRegion2ofthespentfuelstorageracks,fuelisstoredinaclosepackedarrayutilizing fixedneutronpoisonsineachofthestoredlocations.

Fordischarged fuelassemblies tobestoredinRegion2,(1)60daysmusthaveelapsedsincethecorereachedhotshutdownpriortodischarge and(2)thecombination ofassemblyaverageburnupandinitialU-235enrichment mustbesuchthatthepointidentified bythesetwoparameters on'igure5.4-2isabovethelineapplicable totheparticular fuelassembly.

design,therefore assuringthatKeff<0.95.Amendment No.Proposed 5.4.4~~Thespentfuelstoragepitisfilledwithboratedwaterataconcentration tomatchthatusedinthereactorBasiscavityandrefueling canalduringrefueling operations wheneverthereisfuelinthepit.ThecentertocenterspacingofRegion1insuresthatKeff<.0.95fortheenrichment limitations specified in5.4.2,andforapostulated missileimpacttheresulting doseattheEABwouldbewithintheguidelines of10CFR100~.

InRegion2,Keff<0.95isinsuredbytheadditionoffixedneutronpoison(boraflex) ineachoftheRegion2storagelocations, andaminimumburnuprequirement asafunctionofinitialenrichment foreachfuelassemblydesign.The60daycoolingtimerequirement insuresthatforapostulated missileimpacttheresulting doseattheEABwouldbewithintheguidelines of10CFR100.

ThetwocurvesofFigure5.4-2dividethefuelassemblydesignsintotwogroups.Thefirstgroupisallfueldelivered priortoJanuary1,1984.Thisincorporates allExxonandWestinghouse HIPARdesignsusedatGinna4ThesecondcurveisfortheWestinghouse Optimized FuelAssemblydesigndelivered toGinnabeginning inFebruary19843Theassemblyaverageburnupiscalculated usingINCOREgenerated powersharingdataandtheactualplantoperating history.Thecalculated assemblyaverageburnupshouldbereducedby10%toaccountforuncertainties.

Anuncertainty of4%isassociated withthemeasurement ofpowersharing.Theadditional 6%providesadditional margintoboundtheburnupuncertainty 5.4-2Proposed associated withthetimebetweenmeasurements andupdatesofcoreburnup.ThecurvesofFigure5.4-2incorporate theuncertainties ofthecalculation ofassemblyreactivity.~

References 1.Letter,J.E.MaiertoH.R.Denton,January18,1984.2.LetterJ.E.MaiertoH.R.Denton,January18,1984.3.Criticality AnalysisofRegion2oftheGinnaMDRSpentFuelStorageRack,Pickard,LoweandGarrick,Inc.March8,1984.4.Letter,T.R.Robbins,Pickard,LoweandGarrick,Inc.toJ.D.Cook,RG&EMarch15,1984.5.4-3~Proposed f(5>ER>EQ)35L'RRRRRRRXR SRSiSRRRRRRRRRWiRiSi li3S)iAf~R(~RSIIRSSSISSRSIHSRll5%%5515511 eire~ae~ae~aaraaaaaaraaaaaaaaaraaaaaaaraaa 5)<5135)ii)<5%%iiSS5%%iSSiSRiRRSiRHRSSRSR I<Sf<1)3AIJS RRISRISIRR OIIRIRRRRS RRRIIIIHI QCRKI5353555iiSSi%15SSli%iSiSiSSSRSkiSS e~ac~aeiac~aaaaraaaraaaaaraaarrraaarrrxaaa Rt(RC{RAS>i$%%%%5555%5%5SR%5%iSi%555%5HR eireiavai~arraaaaaaaaaraaaaaxaarrarraaaaa RCiiilQKER>3%5i%55%55%5%55%%5%%%5%%%855%5%

RES)iS)3iCOSRSSSRSSHRSXSEiRiiSRRiSRRRRRR Sf<5)ti>EO(iiiRSH%5Qi%%55%%HRQ%%%)

Si%i)<5)3i>EQ)3SRRRiRRSRSRiRRRiRiRSSSiiiSSRRRR if~5j)R)<RKiRIIRB1QQRHIRRRQIRQ11SRQI it(RKESf(if(51<SK<if<5)35%<5>

(SRiiRRRRRRRRSESRRRRSRRRRRRRRRRR f<R>~IXf<5555i)X<%>~lit~<5]~(L~(5i~<5%iSS55555%55SSSS>%555iRSS55%

if(5>3S)ER)35@4)35)35>3ifiR]

iSSSRiSgRRiRSOQRiiiRRRSRMRiERii

)3RK~S)ESKER)35>

(R>350<5>

tif<5)~55iSSQS555%5555%5iRSSSSi555i%5 Xi3%f~SK(R>3%35i3A35)3RC<R)3SRRRiSRRRRRRRRRRRRiRiRRRiSRRR55 f~RKERf<if<R>

l5>li>31)35131)3535XISISRRRRSSRRRR>IRSQSSISRSRSI 5)3564fliKER)3E>35 4f(5>3i)3SRRiRESRiRRRRiRiRRRRi SRRRSRRSiR CiOKIQKIRK~SK<53535)3S)

ISfi5)iIi%5'5555iXSiQSiRiSiiiRSSSRiSR RC~RKERC<SC<5)

EQ)35vS)<5>Eifli55iRRNRRi RRiRRESRRR RiiRRRRRRR ae~reii=~ae~auaaaaaaaaaaaaaaraaaraaaaxaaaaaa

)<5><5)35>iR>3555ERSg iRIRRRSRSRiRi555i%%5%5i k)35)35>3A3i 555515SHSRiRSSSSARiSSSRi5555%

Ki5~35)~<5>~~i~

<155%155RESIIRRIRRIRS SSRIRRRRl5 A(<1()l(il(IQSSSSIQWI SILIRSS/SISSQSS51SS 2'20TCtTHEINCH~IjaIuItClll&HECKEUFFEE&ESSEIICO.salasususA461242FIGURE.-230f2010~*!",ar44I~1-3"i4~~ffIl"~~~i'l~a~I3I-*fII'~~'~'IIIte1st~I4Iil'I:;-;I-~rr~~~~ite~'l~'~i'f:fi::!-4's

~+'I*-1~4~11t~~"41'II~*I4sa,1I~41~4~I~Iatt~it:lli4,it'I4I~~~I1"'II1e~4fsi.yea4+I'.'f!I4~~I*1I!lil.'lei~II..3f'~it.tli11'~4f~4~1~F-1~~4~Il4'1~r~ACCEPTABLEFOsits1~,f)11~-1',"N2~4~'I'IO~)e'ill~I1141RE,i)a,iei14t1I~1~14~~";1'4I1tl~~IT4l~1444~4I*~leI~,~~tt~t,~4i'ijI~'I1It'~~~I,4I~*3-1It44'!'~II~'~~fI114rj.!r'I~14II~fti~~)1'~(4-lt~i."~3'.~1st1st14Ifta11~rsaI~-,~r~4~~i'FUELDELIVERED PRIOR~!i'ANUARYI'la'te"111~1,1984IllII~i'L!1st'1:.)':ii,

It~TQLr!is~,4tl4lll:1~I'i~~I1'.lI1stI4~I~IIl~1\tf'l!IsfI~4~i1Z~~lt'.~I~~iII:'ll14rjS."34Il,44~II,~IasaI~It,~fff3.'ilIF~tifl'f~i)s'Ii'~III~~jfai(i!i~I114f)T:~...I-,~(itI~1III'~'I~~III~~~*f,i~li~tiaI4'I1~~~})fl~~~1ir,ill~~i~l;-1'N4~~4*-i~1'4~-,~~~-4tIII7fl;-.I~esastlt~4'liti)i~~I~f~1reIteia)i~tla3~)I.i~l(sfileif!ii);itti~~is1~II~fI~iI(3~lifill(li3TIf;I)1REGIONSOFACCEPTABILITY Al4DUNACCEPTABILITY FORSTORAGEOFSPENTFUELINREGION21I~ail~\1TII~~)flasI,itrlil1eli~;iifrlI'~it~I~i~;l)f$!issl~I\i~I~~)er~t~ae',f1~~I'I~1jf~I~~~~t{sff,i',141slitIt4~'I~flsf','it~IIt4lI~I~1~1't~~)~3:3-',4~i4)PIj~11I~',)i))3CCi4~i11EPTABLEI~l\~~fIfte1irI~4(:;..':.~~~~I~Iiit~~illfaiaft.'}il'fff~fsi'iAi~II~4ilttltl410atif3)TTFUELDELIVERED 7~TTlT14I~Ii~l'I~'-I~4i)lal'I~lt~~T,r16~~lfl;if'I~3.~e-I'fill!3')'s-~I41g~14~~~II~I-lieI~4'I4~41;}i-';ile.~aiif<<~'iit.f)4'I)~~IIi')3!if~~l~il')flet~471'3'I-'t.i~tI)ia,i)it~~~~~~i)ll)~~~4~I,IIte)il~it7ff,af,ffFORI~i4s~is11~I11'tl~~I114TTIEGIONt~~~il~ii~,ii",1~*I,fa,fi'I~II'~~~~air1'"~I-lan1.it;!..if),'

')IIt)lsis'T-'~'FTERJANUARY1,1984'444at;il')'-'IItI~I~~11it~I~Li~I~Ifetr~a~rte'Ii'144t*II'I'~')!a!i:I:3a~~4~I+441'11;~i3'14*4'IeaaaI~!3ii"Iil3'I1.50I2.003.00INITIALENRICHMENT, N/04.00.4.25 BackroundTheoriginalspentfuelstorageracksprovidedcapacityforthestorageof210fuelassemblies.

In1976RG&Erequested, andtheNRCapproved, thereplacement oftheoriginalrackswithhigherdensityracksprovidedbyWachterandAssociates.~,~

Thisexpandedthestoragecapability from210to595fuelassemblies.

In1980,RG&Erequested3 andthe'RCapproved4 modifications tothespentfuelcoolingsystemtoprovideheatremovalcapacityof16x10BTU/HR.Thismodification providessufficient heat6removalcapability forallpredicted fueldischarges inadditiontoafullcoredischarge atleasttotheyear2010.RecentlyRGSEhassubmitted changestotheTechnical Specification toestablish newlimitations onunirradiated fuelenrichmen't (whichhasbeenapproved) andtodeletearestriction onthespacing.ofrecentlydischarged fuelGeneralTheproposedmodification tothespentfuelstoragerackswillinvolveonlythesixwest-most rackmodules(Figure1-1).Theserackswillberemovedfrompoolandmodifiedsothatfuelassemblies canbestoredinwhatwerethewaterboxlocations.

Theremaining threerackmoduleswillnotbemodified.

Themodifications willprovideanadditional 420storagelocations resulting inatotalcapacityof1016*.Thesixmodifiedrackswillbedesignated Region2andwillbeusedforfuelthatsatisfies certainburnupcriteriaandhascooledforatleast60days.The*Amechanical plugpreviously installed inastoragecellwillberemoved.

remaining threerackswillbedesignated Region1andwillbeusedforlowburnupand/orrecentlydischarged fuel.TheenclosedanalysisconformstotheNRCguidanceofApril14,1978.Thisreliesonpastanalyses(References 1thru6)forthosecomponents whicharenotmodifiedorarenotimpactedbythemodification.

Theanalysisisseparated into7sections.

1.Description oftheModification 2.Nuclear3.Thermal-Hydraulic 4.Mechanical, MaterialandStructural 5.Cost/Benefit Assessment 6.Radiological Evaluation 7.AccidentEvaluation Rochester Gas6ElectricutilizedU.S.ToolSDieasacontractor toperformthemechanical, structural andmaterialanalyses.

U.S.Tool8Diepreviously mergedwithWachterandAssociates, thesuppliers ofthecurrentstorageracks.Thenuclearanalysiswasperformed byPickard,LoweandGarrick,Inc.Thedescription ofthemodification notesanexception totheTechnical Specifications (Section3.11.3)thatwillberequiredtoremovethewestmostracksinthepool.Whilethetrolleyoftheauxiliary buildingcraneoritstransported rackwillnottraveloveranyspentfuel,thetrolleywillpassover2-3emptyrowsofarackcontaining spentfuel.Thedistancebetweentheareaunderneath thetransported rackandthestoredspentfuelwillbemaximized toinsurethefuelwouldnotbedamagediftheloadwasdropped.

e1.DescritionoftheModification Adescription ofthecurrentspentfuelstorageracksarecontained inreference 1andsubsequent responses toNRCstaffquestions byRG&E.AgenerallayoutoftheracksinthepoolisatFigurel-l.Theracksascurrently configured arecomposedofthreemajorcomponents.

a0b.c~Therackmodules,whicharerectangular arraysofcellsofwhichoneoutoftwoarestoragecells.Theothersarewaterboxes.Thesupportbases,onwhichtherackmodulesrest,arearectangular construction ofIbeams.Figure1-2givesagenerallayoutofthesupportbasesinthepoolandFigure4-2providesasketchoftherackandsupportbase.Ateachcornerofthebaseajackscrewprovidesalevelingmechanism andliftsthebaseaminimumof2inchesoffthepoolfloor.Tofacilitate coolingwaterflow,holesarecutintothesupportbaseIbeams.Thejackscrewsbottomhemispherical

.headrestsonsteelplateswhichrestonthepoolfloor.Seismicsupportsbetweenthebasesandthepoolwallsprovideameanstotransmithorizontal loadsfromtherackstothewalls(seefigure1-2).TaskDescritionofModification 1.Shufflespentfueltotheeastmostpositioninthepooltoallowaccesstothetwowestmostracks.

z.Diversloosenthefourmountingboltsfastening theracktothebaseinthetwowestmostracks.Comment:Asaresultofstep1,atleast8emptyrowsoffuelcellswillbebetweenthediversandanyspentfuel(Figure1-1).3.Installtheliftingrigintherackandusingtheauxiliary buildingcraneremoveitfromthepool.Astheracksclearthepoolsurfacedecontaminate withhighpressurewater.Moverackoverthedecontamination pitdirectlytothesouthofthespent.fuelpoolandplaceonJskid.Performadditional decontamination asrequired.

Comment:Boththespentfuelpoolandthedecontamination pitsitonbedrock,therefore, thesafetysignificance ofarackdropduringtransferisminimized (SeeFigure1-3).Forthemodification, atemporary platformwillbebuiltoverthedecontamination pitonwhichtheworkwillbeperformed.

TheGinnaTechnical Specifications prohibits thetrolleyoftheAuxiliary Buildingcranefrommovingoverrackscontaining spentfuel(Section3.11.3).Forthefirsttwowestmostracksthiswillbeviolated.

However,thetrolleyorthetransported rackwillnotpassoveranyspentfuel,but2to3emptyrowsofarackcontaining spentfuel.Shouldaloaddropoccurthedistancebetweentheserowsandcellscontaining spentfuelwillpreventfueldamage.Duringthedecontamination processoverthepool,thepoolboronconcentration willbecheckedfrequently.

4.Usingaspecialcuttingmachineremove70guidefunnelsand~~28guideanglesoverthewaterboxes.5.6.7.8.Remove4lifterassemblies andinstallmodifiedbottom'plateswithliftingslots.Enlargethe,flowholesinthebottomplates,andinstalladditional 1/2"bottomplatestotheformerwaterboxes.Installtheright-angled poisonassemblies ineachcelloftherack.Diversinstallshimsatthecornersofthesupportbaseandretractjackscrews.Baseandrackloadswillrestontheshims.9.Setracksinpoolonsupportbaseswithoutthemounting~~bolts.10.Repeattheabovestepsuntilthesixwestmostracksinthepoolhavebeenmodified.

11.Removeall(bothRegion2andRegion1)seismicsupportsbetweentherackbasesandthewalls.Inordertoremovethetwowestmostracksthespentfuelpoolcoolingsystemdischarge pipewillhavetoberemovedwhereitdescendsthewest,wallofthespentfuelpool.Thedecayheatloadduringthetime'period ofthemodification willbesmall(<2MBTU/HR) becausetheprojected starttimeforthemodification ofOctober1984willbeatleastsixmonthsafterthedischarge ofthelastreloadbatch.Theheatcapacityofthepoolissuchthataheatuprateassumingnoheatlossesduetoevaporation orothermechanisms islessthan1'Fperhour.Atemporary fittingandhosewillbeusedtoreturncoolingwatertothepool.

Shouldcoolantflowbelost,theslowheatuprateandthetypically lowinitialtemperature ofthepoolwillensureadequatetimeisavailable forthenormalbackup(skidmountedpumpandheatexchanger) emergency coolingsystemtobeputintooperation.

Assoonaspossibleafterthetwowestmostracksarere-installed, thenormalcoolingpathwillberestored.

~SEA~C~ESSSSSSSSS~~

ESSSESESSESIK(SEERESS~

~ERERSRS~EEEEEEEEEESSI')

5a><gf<Sftgfi 5I>E%KIRK(RK(kftQKES SEE~~ERR~SRRSRESSSSSSSSSSSSSS ESK%4SK~RRSRWSWASEESEESRSXI PM5$LLLR~EuaaeKIESSSESESS N~-){555%%6KERRSSSSSSRRRSSM555 555SSMQ%5 OK(%5%)(%hi%5'5%3RMMK%6WK~%5%%~%

%45W$355%K(RKiXK(RORti

%RRK%555K(RE<K(ROk~H a5555%8K45RRSSI>INNSR5 i~rrrraxraa 5>SQRRARRK(

05SN1S-->A(i<5-.55SRSR)(>(R~SManrraarri~

t4NiNNS51%NSQSRid N5958OK~MQM885 K<SRX5555M RQMRWRNSlMRi'%$%2%555$

K~RFiRK%-I II~v~vSII'L'Pg%.LPI)~(ISO.io)I(1/AI)s'.l/sr)"O.&l)s(aea')s((ta4.uO)a4)',s~!(5()T.44"IG.(()(0em~4)hg(()144JI'/b(Io.cc')(La.w+4)I(.~/sa(4X4C)(IA.447s(0aca~ptdi)0g.y)+50IIIIIIgo~(v%VEAUSs~~4)s4vWg~vI:c";Iss~~ia-~~ls11~I~I'I~~A~.s.s')'ZtI~~sv1Saon)s4Vv+++~s041440(sl'->Pl.I~~v>.&1,/s0I(Ivz.)I;II4f4'rV$gofg~IgiI~oarereyeoio;+(I'Io%4ooaa4-I+CggLsvvIs~01~(I20JI~~Ig(v4L4~v0~~v1v4IoI11%.bl)s(r44)a+4O.Isola4)(4144I V)<}I=~vI)~~'~~~II)J~~/VhlEWSL'EL6"EVA7ogLIF>ivfKi~CH.I2wI~gznv~d/gga//(NEctZ-~I'5la=Fuaa.%t~wi.tpl..'SSI<ti~v)):D-C)I<t-Oa7)

-'VIIR)IT Ctt)CJPAV)8.i(C,wesT)FVVKLClhJVV'O)VVI)V))l}

4)IL)V,~'ihtEL.l-SO.0V~C~t.T&~lhl<b),Tl O&.vP)T~Fl.eaR.ELEV749i~.lI~IilJIII.+&8t)LtJPO2-I-<7))l)!cvARC6+O'L

+~~~A"'E'l'R7Q'-4FPS'-/o"~6-/OFIGURE1-3~~AUXILIARY BUILDINGSPENTFUELPOOLAREA~4VV~)gtl)PV'~~~)~~-~4JExya~dwA~<;>woeV'I4iI~HEOJ.PLKLORAGKAREASEEDl<A4JlN(q,O

-oA.-00'7.,I))p~~=xnan,:sAx.,~<~"rz 1mcl~~~~$47~8//CIIz4'-r'0 2.NuclearAnalsisAttachedisanuclearanalysisofRegion2rackconfiguration performed byPickard,LoweandGarrick.Thisanalysisestablishes theminimumburnupsasafunctionofinitialenrichment requiredinorderforafuelassemblytobestoredinRegion2.Thisanalysiswasperformed fortheWestinghouse Optimized FuelAssembly.

Reference 23addedtheExxonzircaloyguidetubedesign(Regions13-15).TheExxonRegions13-15differfromtheearlierExxonRegions10-12onlyinthatthelaterregionsincorporate zircaloyguidetubeswhiletheearlierregionshadstainless steelguidetubes.ThelaterExxonregionoffuelwillbemorereactivethantheearlierregionatanyburnupbecauseofthisdesignchange.Therefore, theminimumburnupcriteriaforRegion2generated forExxonRegions13-15willbebounding.

TheotherfueldesignusedatGinnawastheWestinghouse HIPARdesignwhichincorporated inconelgridsandstainless steelguidetubes.Table2-1showsacomparison ofdesignparameters forthosefuelassemblies usedatGinna.Reference 23documented thattheWestinghouse HIPARdesignislessreactivethantheExxonRegions13-15designatanyburnup,therefore theminimumburnupcriteriagenerated fortheExxondesignwillbeboundingfortheWestinghouse HIPAR.Inordertodetermine theburnupofanindividual assemblyfollowing discharge, RGKwilluseitsNuclearFuelAccountability Code(NFAC)whichwasestablished intheearly1970'storecordtheisotopiccontentofthefuelandotherspecificparameters suchasburnupforuseinfuturefuelreprocessing.

NFACusesasinputtheburnupratedata(Mw-hrsper1000coreMw-hrs)generated byINCOREresultsfromfluxmeasurements.

Everyassemblyirradiated atGinnaisfollowedwithNFACbeginning withinsertion andproceeding throughcorelifetodischarge.

Theseburnupsgenerated byINCORE-NFAC willbereducedby.afactorof10%toconservatively boundmeasurement uncertainties.

Thisreducedburnupwillbecomparedtothecurve(Figure5.4-2ofproposedTechnical Specification) todetermine ifafuelassemblyisacceptable forstorageinRegion2.Asdescribed, inSection1,everycellofthemodifiedrackswillhaveBoraflexneutronpoisoninsertsinstalled.

Specificqualitycontrolprocedures willbeusedtoinsurethepresenceoftheBoraflexineverycell.Properdocumentation fromthemanufacturers ofBoraflexwillbeobtainedtoassuretheminimumBdensity.Adiscussion ofmechanical stability ofBoraflexisatSection5,Mechanical Analysis.

Referring toFigure4-4,PoisonAssemblyInstallation, thelengthofthepoisonmaterialinthecellis132inches.This.comparestoamaximumfuelassemblyactivefuellengthof142inches.Theendsoftheactivefuelregionwillbeataburnuplowerthantheassemblyaverage.However,thispositivereactivity effectwillbeoffsetbytheincreased neutronleakageattheendsofthefuelregion.Additional calculations arebeingperformed toquantifythenetreactivity effectofthepoisonconfiguration.

Theresultsofthesecalculations willbeforwarded whenavailable andthepoisonmaterialregionextendedifrequired.

Table2-1Comparison ofDesignParameters RodArrayRodsperAssembly"Westinghouse HIPARREGIONS1-914x14179ExxonREGIONS10-1214x14179179179Westinghouse OFA13-15REGION1614x1414x14RodPitch,In.AssemblyPitch\ActiveFuelHeight,In.CladO.D.,In.CladThickness, In.CladMaterialPelletDiameter, In.ametralGap,In.PelletDensity,%GuideTubeO.D.,In.I.D.,In.GTMaterialInstrument TubeO.D.,In.I.D.,In.ITMaterialIGridsGridMaterial.5567.803141.4-142.0

.422.0243SS-304.3659.007594.5375.5075SS-304.422.3455SS-304INCONEL.5567.803142.0.424.030ZRC.3565.007594.540.510SS-304.424.346SS-304ZRCwINCONELSPRINGS.5567.803142.0.424.030ZRC.3565.0075'94.541.'507ZRC.424.346ZRCwINCONELSPRINGS.5567.803141.4.400.243ZRC.3444.007095.5280.4825ZRC.4015.3499ZRC,7-ZRC2-INCONEL"TheseareRegion8parameters.

Therewereminorvariations insomeoftheseparameters overtheregions.

3.ThermalHdraulicReference 4containstheNRCsafetyevaluation ofproposedspentfuelpoolcoolingsystemmodifications andapprovalthatthesewouldprovidesufficient coolingcapacityforprojected discharges throughyear2009withafullcoredischarge inyearI2010(1360fuelassemblies total).Thiscoolingcapacityexceedsthemaximumthatwouldberequired=

undertheproposedmodifications (1016fuelassemblies total).Thecurrentprojected refueling cyclesareconsistent withtheassumptions ofthissafetyanalysis.

Itisanticipated thatthismodification willbecompleted during1986.Thecurrentspentfuelpoolcoolingsystemcapacityis9.3x10BTU/HR.-Thisisfarinexcessofwhatwillberequiredundernormalconditions priorto1986(discharge ofonlyoneregionoffuelat.endofeachcycle).Ifafullcoredischarge isrequiredpriortothenewspentfuelpoolcoolingsystembeinginoperation, thein-reactor decaytimewillbeextendedinordertoensurethepooltemperature limitations intheTechnical Specifications aresatsfied.

InresponsetoNRCquestions concerning thepreviousstoragerackmodification, RG6Ecalculated themaximumcladdingtemperature forthehottestfuelassemblyofarecentlydischarged ba'tch,discharged inconjunction withafullcore.Thiscalculation kshowedamarginofover80'Ftothesaturation temperature.

Thisassumedarecentlydischarged batchgroupedtogetheratastoragelocationfarthestfromthecoolingsystemcoldwaterinlet.ThisanalysisisstillvalidforRegion1where,inaccordance withtheproposedTechnical Specification (Section5.4.4),recently discharged fuelwouldbestoredforaperiodofatleast60daysafterreactorshutdown.

After60daysofcoolingtimethefuelcouldbemovedtoRegion2'shigherdensitystorage.Aspartofthemodification, theflowholeatthebottomoftheformerwaterboxeswouldbeenlargedtoequalthatoftheotherstoragelocations.

Asindicated intheanalysis, adequateflowwillbeavailable tothehotterthanaverageassemblies andthereisnolimitingthermalrequirement whichwouldpreventthegroupingoftheseassemblies~

10 4.Structural Mechanical MaterialAnalsesA.SeismicAnalysisTheobjectives ofthisseismicanalysisaretodetermine thefollowing'during OBEandSSEseismicevents:1.Themaximumloadsimposedonthefuelstorageracks.2.Themaximumdistancetherackswillslideand/orliftoff.Theresultsofthisanalysiswillbeusedinthemechanical analysistoevaluatethestructural integrity oftherackswhensubjected totheseloadsandmovements.

~ScoeTheloadingsconsidered inthisreportforthemodifiedracksusingbothstandardfuelassemblies andconsolidated fuelwitha2:1compaction ratioare:1.Deadweight ofthefuelstorageracksandthefuelassemblies.

2.Submerged weightsofthefuelstorageracksandthefuelassemblies.

3.Seismicloading,bothOBEandSSE,asprovidedbytheacceleration timehistoryatthepoolfloor.Horizontal responses totheseismicaccelerations oftheracksareobtainedbyevaluating theloadingsfortwodifferent boundaryconditions.

1.Thehorizontal motionisrestrained byahorizontal forceequalto0.2timesthenormalforce.Thisistheminimumanticipated frictionfactorbetweentherack andthesupportstand,(Ref.13).Theseresultsgivethemaximumdistancetherackswillmoveduringaseismicevent.2.Differential motionbetweentherackandthesupportstandisprevented.

Thisismodeledinthefiniteelementrepresentation byplacingahorizontal spring,representing therackflexibility, betweentherackandafixedpoint.MethodsofAnalsisTheverticalseismicanalysiswasperformed usingtheequivalent staticresponsespectramethod.Thisconsistsofdetermining theverticalnaturalfrequency tobegreaterthan33HZ,thenusingaccelerations of0.23gforOBEandSSEtakenfromtheresponsespectracurves~4.

Thesevalueswereappliedtothedeadweight toobtainthetotalverticalforces.Theverticalreactionloadswerecombinedwiththehorizontal seismicloadsusingthesquarerootsumofthesquaresmethodasspecified inRef.8.Horizontal seismicanalysiswasperformed usingthetimehistorymethodofanalysisinconjunction withtimehistorydata.TheOBEtimehistorydatawasobtainedbydividingtheSSEtimehistorydatabytwo.Thisaccountsforthenon-linearities inherentinthespentfuelstoragerackswhichinclude:1.Fuel-to-rack wallimpacts2.Racksliding3.Verticalimpactduetoracktipping.Thetimehistoryanalysiswasperformed usingaspecialpurposecomputerprogram"RACKOE"*.

Thisprogramwasdeveloped

• RACKOEisanacronymforrackanalysisconsidering kineticsofearthquakes, anonlinearfiniteelementprogramdeveloped byProf.W.F.StokeyofCarnegie-Mellon University, Pittsburgh.

12

specifically toanalyzefuelstoragerackbehaviorresulting fromseismicdisturbance.

Thisprogramsolvestheequations ofmotionexplicitly usingEuler'sExtrapolation Formula.Thefuelrestsinthecellbase.Itisassumedtoactasapinnedbeam,centeredinthecell,withagap,between thecellandthefuelalongitslength.Thegapsbetweenthefuelandthecellwallscanclosecausingimpacttothewalls.Thespacebetweenthefuelandthewallisfilledwithwater.Asthefuelandthewallmoverelativetoeachother,hydrodynamic forcesaresetupduetotheacceleration ofthewater.Theseforcesareexertedonthefuelandrackstructure, tendingtomitigateIimpactforces.Hydrodynamic forcesaregenerated betweentheracksandthepoolwalls.Methodsdescribed byFritz(Ref.9),Dong(Ref.10)andStokey(Ref.11)areusedtoquantifythesehydrodynamic forces.DampingvaluesusedforthisanalysisaretakenfromRegulatory Guide1.61,(Ref.12).Therackboxesareweldedtogether.

Whentheweldsarestressedtherewillbesomelocalized deformation.

Thedampingvaluesarebetweenthoseforweldedsteelandboltedsteelstructures.

Intheinterestofconservatism thelowervaluesforweldedsteelstructures areused.Friction, betweentherackandthepoolsupportstand,ishandledbyaspecialfrictionelementofthemodel.Thenormalforceonthiselementistheforceintheverticalsupportswhich,duetoracktipping,canbegreaterthanthedeadweight oftherack.13 EimentDescritionandMaterialProertiesEquipment Description Section1providesadescription ofthemodification.

AsshowninFigure4-1,thewestsixrackswillbemodifiedtoallowhstorageofspentfuelinwhatarecurrently waterboxlocations.

Theserackswillbedesignated Region2andwillincorporate neutronabsorbing mateiialineachlocation.

ShimsareaddedundertherackbasesinRegion2toprovideanincreased loadtransferarea.Slidingisaccomodated intheRegion2racksbetweentherackandthebase.supportbyremovaloftheboltsbetweenthetwo(Fig.4-2).TheRegion1racksareunmodified andtheirstoragedensityandloadsremainthesame.Inthiscaseslidingwouldoccurbetweenthejackscrewsateachcornerofthesupportbasesandthe11"x11"plateswhichrestonthespentfuelpoolfloor.Inaddition, alltheseismicsupports(bothinRegion1andRegion2)betweenthesupportbasesandthespentfuelpoolwallswillberemoved,therefore noloadswillbetransmitted tothewallsbyeitherregionofracksasindicated bytheresultsbelow.Theamountofslidingisinsignificant comparedtothe(racktowallclearance orthedimensions oftheplatesonwhichtheRegion1supportbasejackscrewsrest.Alsotheracksrespondin-phasetoseismicevents,thustherewillbenoaddedimpactloadsattheRegion1-Region2interface.

Theanalysisisperformed forthe140cellsizerackwhichiscommonforallsixinRegion2.Thecellcross-section isshownonFigure4-3andthelongitudinal sectiononFigure4-4.-14

/Twostoragearrangements areanalyzed.

Oneisreferredtoas"standard" whereinonefuelassembly(179fuelrods)isstoredineachcell.Theotherisreferredtoas"consolidated" whereinthefuelrodsfromtwoassemblies (358fuelrods)contained inastoragecanisterarestoredineachcell.Figure4.5showsthearrangement ofthefuelrodsinthecanister.

MaterialProertiesApplicable from70to200degreesF.Thespentfuelracksarefabricated fromtype304stainless steel.The304SSrackmaterialproperties usedintheseismicanalysisare:(Ref.14)DensityYoung'sModulus501.0PCF27.8E06PSIShearModulus10.7E06PSIThefuelassemblies containcladconstructed ofZircaloywhoseproperties are:(Ref.15):DensityYoung'sModulusShearModulus409.0PCF13.0E06PSI5.0E06PSIOtherdensities usedintheanalysisare:.Water62.4PCFUO2643.0PCF

ResultsAfiniteelementrepresentation ofarackwithfuelassemblies isshownonFigure4-6where:RackatBase(Horizontal) 2-6Rack(Horizontal) 7-11FuelAssy.(Horizontal) 12RotaryInertia13Rack6FuelAssy's(Vertical)

Represents FlexibleElements1-5Rack6-10FuelAssy.11Horizontal Support12,13VerticalSupportsRepresents GapElementsMHrw=Hydrodynamic Mass(RacktoWall)MHrf=Hydrodynamic Mass(RacktoFuel)Theresultsaresummarized for:a.StandardRack-140FuelAssy's-179 FuelRodsPerAssy.b.Consolidated Rack-140FuelCanisters-358 FuelRodsPerCanister.

Thetabulated resultsaregroupedandidentified by"sets"numbered1thru5.Thevaluesineachsetareexplained below.SETgl-MaximumForces(KIPS).SETC2-LoadsonIndividual F/A's(LBS)andSupport(KIPS).Themaximumcontactforcesaretheforcesofset51divided-bythenumberoffuelassemblies intherack.Thesupportforcesaretheforcesofset1dividedbytwo.Twosupportstakethegivenreaction.

16 SET53-MaximumForces(LBS)attheRackSupport.TheFvertValues,NS,EW,VT,arethevaluesofset1minusthesubmerged weight.(Ex.271,700-208,190=63,510)TheFhorizValues,NSandEW,aretakenfromset1.TheVerticalForces,VT,aredetermined byusing:OBE=0.23gSSE=0.23gFromtheresponsespectracurvecorresponding to33HZ~4.VT(OBE)=(1.23DWT-BUOYANTFORCE)-SUBMERGED WT.VT(SSE)=(1.23DWT-BUOYANTFORCE)-SUBMERGED WT.TheRMSValuesarecalculated using:RMS=SUBMERGED WEIGHT+Fns.+Few+FvtSET54-MaximumForces(LBS)onEachSupport.ThesevaluesarethevaluesofSet83dividedby2.SET05-Horizontal andVerticalMovement.

oftheRack(Inches)ELASTIC-Theamounttherackwilldeformasaresultoftheinternalflexibility oftherackwhenrestrained fromhorizontal motion.SLIDING-Theamounttherackwillmovewhentherackisconsidered rigidanda0.2frictionfactorisusedtorestrainmovementinthehorizontal direction.

LIFTOFF-Themaximumvaluestherackwillmovevertically offofthebase,ortip,duringtheseismicevent.TheValuesDWT,BWTandSWTareDeadweight, BuoyantWeight,andSubmerged Weightrespectively.

17 Thefrictionforcesarethemaximumhorizontal forcesdeveloped atthebaseofrackusingaminimumfrictionfactorof0.2.18 PROJECT8369SUMMARYOfRESULTSFOR140CELLRACK.ISET¹1-MAX.FORCESATGAPELEMENTSDIR,EVT12345STANDARD.

FILERGSUM.1(KIPS).SUPPORTFvtFhxEWOBENSSSE0.055.672.473.273.28.962.098.377.'797.6NSOBE31.453.253.364.483.5271.7170.0393.3156.2404.7231.5EWSSE16.666.5115.883.9.103.3381.6164.2-----SET¹2NSOBELOADSONINDIVIDUAL FIA'(LBS)ANDSUPPORTS(KIPS)---224.380.381.460.596.135.985.0EWOBE0.397.517.523.523NSSSE64.443.702.555.697.196.778.1202.4115.8EWSSE119.475.827.599.738190.882.1-SET¹3-MAX.FORCESATSUPPORT(LBS)FvertFhorixNSOBE63,510.170,000.-SET¹5-MOVEMENTATBASE(INS)ELASTICSLIDINGLIFTOFF0.0190.0800.009EWOBE185,110.VTOBE5.3,728.RMS411,133.NSSSE196,510.EWSSE173,410.VTSSE53,728.RMS475,723.156,200.00,000.230,865.231,500.164,300.00,000.283,878.0.0460.088-0.0260.308'.048 0.5130.0480.0500.067-SET¹4-MAX.FORCESONSUPPORT(LBS)--NSOBE.31,755.85,000.VTOBE26,864RMS205,567NSSSEEWSSEVTSSE98,25586,705.26,864.EWOBE92,55578,10000,00015432115,750.82,150."00,000.DWTBWTSWTF,RICT80.2NSOBEEWOBENSSSEEWSSEZ33,600.LBS.25,410.LBS.208,190.LBS.IONFORCESFACTOR(LBS)41,640.'2,210.

59,760.101,600.RMS237,86"141,939 PROJECT8369SUMMARYOFRESULTSFOR140CELLRACK-SET¹1-MAX.FORCESATGAPELEMENT¹DIREVT123R5NSOBE0.00.0100.098.4159.3EWOBE0.053.&178.3176.0180.1l~NSSSE14.8214.9225.6217.5250.7'A1lEWSSE0.0118.0249.3223.2235.0---'--SET

¹2-LOADSONINDIVIDUAL F/A'NSOBE00.00.714.703.1138.EWOBE00.383.1270.1257.1286.NSSSE106.1535.1611.1554.1791.EWSSE00.1060.1781.1594.1679.CONSOLIDATED.

FILERGSUM.2(KIPS)SUPPORTFvtFhz312.4160.2405.2153.0455.7239.3512.1184.7(LBS)ANDSUPPORTS(KIPS)----

156.280.1202.6.76.5227.9119.7256.192.4-SET¹3-MAX.FORCESATSUPPORT(LBS)FvertFhorixNSOBE00.160,200.-SET¹5-MOVEMENTS ATBASE(INSELASTICSLIDINGLIFTOFF-0.0180.0280.000EW.OBE64,140.VTOBE89,470.RMS451,146.NSSSE114,640.EWSSE171,040.VTSSE89g470.RMS565,564.153,000.00,000.221,524.239,300.180,700.00,000.302,'289.

0.0270.0940.0540.1280.0170.0720.0050.0240.015-SET¹4-MAX.FORCESONSUPPORT(LBS)--NSOBE00.80,100.!-eVTOBERMSNSSSEEWSSEVTSSE44,735.225,573.57,320.85,520.04,735RliS282p782EWOBE32,07076,50000,000.110,762.119,650.92,350.00,000.151,144.DWTBWTSl/T389,000.LBS.47,940.LBS.341,060.I.BS.FRICTIONFORCES80.2FACTOR(LBS)NSOBE=49,640.EWOBE=51,630.NSSSE=68,210.EWSSE=68,210.BECAUSEOFHOLIFTOFF.

B.Mechanical AnalysisIntroduction Thespentfuelstorageracksareclassified ascategory1perNRCRegulatory Guide1.29.Theirprimaryfunctionistomaintainstoredfuelassemblies inasubcritical arraywhileprotecting themfrommechanical damageduringallcrediblestorageconditions.

Themechanical analysispresents.

analytical proofofstructural integrity.

TheanalysisfollowsNRCguidanceasdelineated inthepositionpaper"ReviewandAcceptance ofSpentFuelStorageandHandlingApplications",

datedApril14,1978andmodifiedJanuary18,1979.Thedesigncalculations arebasedonsubsection NFofASMEBoilerandPressureVesselCode,SectionIIIandAppendixDoftheStandardReviewPlan(SRP)3.8.4.Thepermissible weldstressesaretakenfromTableNF-3324.5(a)-1,1983 edition.ThisisthesameasTableNF-3292-1, 1977edition,referredtointhepositionpaperandinNF-3321.Thistablenolongerexistsinthe1983edition.Theloadcombinations usedinthisanalysisareonlysubmerged deadweight plusSRSScombinations ofOBEandSSEloads.Theseloadcombinations aretheRMSvaluestakendirectlyfromtheseismicanalysis(Section4A).Theracksarenotsubjected toliveloadsnortothermalloads.Thustheloadcombinations, D+L+To(or Ta)+EandD+L+Ta+E'ecome D+EandD+E'.19 Analysesareperformed fortwostoragearrangements, onereferredtoas"standard" whereinonefuelassembly(179fuelrods)isstoredineachcellinRegion2,theotherreferredtoas"consolidated" whereinthefuelrodsfromtwoassemblies (358fuelrods)inacanisterarestoredineach'cellinRegion2.Theinterface betweentheracksandbasesisthecruciform bottomplateattherackcornerswhichspanthreeboxesineachdirection.

Thustheplaneatthethirdrowlocation, asshownonFigures4-7and4-8,andthethree-box cornersquarearetheweldplanesanalyzed.

FloorloadsforRegion2aretransferred throughthebasetothell"x11"floorplates.Becauseoftheincreased storageinRegion2,shimsareinstalled betweenthebasecornerandeachfloorplatetoprovidegreaterloadtransferareathanthepresentjackscrews (Fig.4-9).InRegion1,however,sincenochangein,storageisbeingmadethereisnochangeinbasetofloorplates,i.e.Thejackscrews remain.Theregion1racksarenotbeingmovedfromtheirpresentlocations, andwith.thejackscrews centeredonthe11"x11"floorplatesthereisenoughdistancetotheedgetotakecareofanysliding.Therearenocalculations forwallloadsbecause,asfreestanding racksandbases,duetoremovalofthewallseismicrestraints, therearerelatively largedimensions betweentheracksandwallsandconsequently smallhydrodynamic forces.Theseapproximate dimensions areindicated onFigure4-1andarelargecomparedto,themaximumslidingdistanceof.5inches.20 References 1and2providedanevaluation offuelhandlingaccidents andconcluded thattherackstructure protectsstoredfuelfromtheimpactofadroppedfuelassembly.

Apostulated dropaccidentofafuelassemblystraightdownintoastoragecellisincludedinthereportbecauseitwasnotpreviously addressed.

EimentDescritionSixoftheninepresently installed rackswillbemodifiedfor100%storagedensity,anddesignated asRegion2forstorageofdepletedfuel.Theremaining threeracks,unmodified, areCdesignated Region1forstorageofunirradiated orfreshlydischarged fuelat50%storagedensity.AllsixracksinRegion2arethesamesize,140storagecells.Themodification consistsofremovingthepresentboltconnections betweenracksandbasesandthewallseismicrestraints, resulting inafree-standing array.Thewallseismicrestraints arealsoremovedfromRegion1.Additionally, afull-length rightanglepoisoninsertisweldedineachRegion2cell,asshownonFigure4-3andFigure4-4oftheseismicanalysis(Section4A).Asketchofrack,base,shims,andfloorplatesisrepresented inFigure4-9.Theshimsareaddedbetweenthebaseandfloorplatesin"ordertoprovidemoreloadcarryingareathanthepresentjackscrews.

LoadsfromtheSeismicAnalsisTabulation ofloadsfromtheseismicanalysisareinSection4A.Theloadcombinations ofD+E(OBE)andD+E'SSE)aretheRMS21 valueslistedatSet43.Maximumverticalloadsarethoseoccuringon2ofthe4rackcornersatreturnimpactfollowing lift-off.

Set54ishalfofset53ortheloadonasinglecorner.Thestressesaresummarized inTable4-1for:a.Shearinweldsno.1,2,S3shownonFigures4-7and4-8.b.Shearoutofthecorner9boxes(shadedarea,Fig.4-7).c.Bucklingoftheboxwallsd.Floorloadsunderthell"x11"baseplateThestressesinweldsno.1,2,63aredetermined bycalculating theRMSvaluesoftheshearload,verticalandhorizontal, togettheNS,EW,VTandSWTloads.Theforceintheweldiscalculated by:S2+2SubmeredWeiFSWTFnFewFvt(SWTzsgght)Theshearoutofthecorner,thebucklingloadontheplateandthefloorloadaredetermined byusingtheRMSvaluesfortheindividual supportsgiveninSection4A.Themaximumstressesinwelds1,2,83are:STD.Rack,E-WPlane,OBE,19,970psi,Weld52STD.Rack,N-SPlane,SSE,21,700psi,Weld02CON.Rack,E-WPlane,OBE,16,940psi,Weld52CON.Rack,E-WPlane,SSE,23,340psi,Weld01Themaximumshearoutstressesinthecornersare:STD.Rack,OBE,11,940psiSTD.Rack,SSE,13,800psiCON.Rack,OBE,13,110psiCON.Rack,SSE,16,430psi22 Themaximumfloorloadsinthell"x11"baseplateare:STD.OBE,1700psiSTD.SSE,1965psiCON.OBE,1860psiCON.SSE,2340psiTheallowable weldOBEshearstressis24,000psi.(Ref.14),Sect.NF3000,TableNF-32921-1)Theallowable weldSSEshearstressis38,400psi(1.6OBE(USNRC,SRP3.8.4.5(b))

Thecriticalbucklingstressis19,140psi(Ref.21pg.2.12)FloorLoadsThesixmodifiedracksareinRegion02.Usingthesubmerged weightfortherackandcontained fuelassemblies thetotalfloorloadsare:StandardRackConsolidated RackI1,249,000 LBS.2,046,360 LBS.THEBEARINGSTRESSONTHECONCRETEUNDERTHElliiXll>>X3/4~iSUPPORTPLATESAREBEARINGSTRESS(PSI)17001965STANDARDRACKOBESSEFLOORLOAD(lbs)205,567237,862CONSOLIDATE RACKOBESSE225,573282,78218642337Theallowable concretebearingstressis3570psi(Ref.22).23 TABLE4-1SUMMARYOFSTRESSESSTRESS(PSI)NORTH-SOUTH PLANESTANDARDCONSOLIDATED STRESS(PSI)EAST-WEST PLANESTANDARDCONSOLIDATED OBESSEOBESSEOBESSEOBESSEWELD//1WELD//2WELDg3CORNER>'c SHEAROUTBOX"BUCKLINGSTRESS1168016200798017330184801866014260212601480021700112802210019970202701694023340113501770012170172001888019320167202243011,95013p80013yll016p430.ll)95013p82013pl0016p4308,80010,2009,67012,1208,80010,2009,67012,120MAX.~FLOORIOADS1,7001,9651,8602,3401,7002,0001,8602,340*Thesevaluesarecommontobothplanes.24 StraihtDroofaFuelAssemblThrouhanIndividual CellAnanalyseswasperformed todetermine

.theaffectofafuelassemblybeingdroppedontoorintoaspentfuelrack.Theconsequences ofadropontoarack,inwhichtheassemblyimpactsthetopofthefuelboxes,haspreviously beenaddressed andfoundacceptable (Ref.1,2).Itwasshownthatafuelassemblyisnotdamagedbythisdrop.Anassessment isprovidedbelowofafuelassemblybeingdroppeddirectlyintoafuelbox.Sincetheclearance betweenafuelassemblyandafuelbox,eveninthemaximumboxsizeconsidering tolerances, isontheorderof.2inches,itisunlikelythatthiswouldoccur.Itismostlikelythatthefuelbundlewillstrikethetopofthefuelboxandbedeflected sothattheenergyisdissipated indeformation oftheboxorfuelbundleitself.Thispostulated dropaccidentwouldcausethefuelassemblytoimpactthebottomplateinthecell.Theclearance betweenfueldimensions andboxdimensions arequiteclose;thusthefuelassemblywouldactasaleakypistonandthefuelboxwouldactasaleakycylinder.

Thehydraulic forcesgenerated whenthefuelassemblyinitially entersthefuelboxwouldbequitelargeandwouldservetoretardthefuelassemblyduringthenext13.25feetofitsdescent.The0.090"weldswhichattachthebottomplatetothecellwouldbeplastically deformedtofailureifloadedhighenough.Thisfailureloadestimateisbasedon25

'I30,000psiultimateshearstrengthandatypicalplasticdeformation of20%.Theareainshearis0.090"x4(8.25")=2.97in.Energy=30,000psix(20%x0.090")x2.97in.=1604in-lbs.Comparing thisvaluetotheenergyavailable from.thestraightdropontherack,whichis43,500in-lbwhenthefuelassemblyisconsidered asarigidbodyfora30"drop,thebottomplateweldswouldfail.Sinceeachbottomplateofafuellocationisindividually weldedtoitsfuelbox,failureof'onebottomplatewouldnotaffectanyotherfuellocationofstoredfuel.Thus,thepostulated fueldropwouldonlyresultinonestoragelocationbeingrenderedunuseable.

Inaddition, theconsequences fromaradiological standpoint areunchanged sinceonlyoneassemblywouldbeaffected.

Also,sincethephysical.

configuration ofthespentfuelstoragecellswillnotbechanged,thesub-critical arrayoftherackismaintained';

NeutronAbsorbinMaterialTheneutronmaterial,

Boraflex, tobeusedintheGinnamodifiedspentfuelrackconstruction willbemanufactured byBrandIndustrial

Services, Inc.,andfabricated tosafetyrelatedbinuclear criteriaoflOCFR50,AppendixB.Boraflexisasiliconebasedpolymercontaining fineparticles ofboroncarbideinahomogeneous, stablematrix.BoraflexcontainsaminimumBdensityof0.2gm/cm~.Boraflexhasundergone extensive testingtostudytheeffectsofgammairradiation invariousenvironments,*

andtoverifyits26 structural integrity andsuitability asaneutronabsorbing

,material.

Testswereperformed attheUniversity ofMichiganexposingBoraflexto1.03x10"radsgammaradiation withasubstantial concurrent neutronfluxinboratedwater.ThesetestsindicatethatBoraflexmaintains itsneutronattenuation capabilities beforeandafterbeingsubjected toanenvironment ofboratedwaterand1.03x10"radsgammaradiation.

Longtermboratedwatersoaktestsathightemperatures werealsoconducted.

Itwasshownthat,Boraflex withstands aboratedwaterimmersion of240'Ffor260dayswithoutvisibledistortion orsoftening.

Boraflexmaintains itsfunctional performance characteristics andshowsnoevidenceofswellingorlossofabilitytomaintainauniformdistribution ofboroncarbide.Duringirradiation acertainamountofgasmaybegenerated.

However,theabsorberwillnotbesealedwithinthestoragecellandventpathswillbeavailable tothepool.Thiswillpreventgasinducedswellingoftheinsertsandinterference withthefuelassembly.

TheactualtestsverifythatBoraflexmaintains long-term materialstability andmechanical integrity, andcanbesafelyutilizedasapoisonmaterialforneutronabsorption inspentfuelstorageracks.Beyondtheextensive testingconducted, BoraflexisbroadlyusedinhighdensityspentfuelstorageracksintheUnitedStatesandinEurope.Itwasfirstinstalled atPointBeachUnit27 1in1979.Apartiallistofoperating powerreactorusersofBoraflexfollows:PointBeachUnits1&2NineMilePointUnit1OconeeUnits1&2PrairieIslandUnits1&2Theextensive testingandthebroadindustryexperience withCalvertCliffsIIQuadCitiesUnits1&2H.B.RobinsonUnit2theuseofBoraflexobviatestheneedforaGinnaspecificsurveillance programoftheneutronabsorber.

Anypotential longtermproblemswilldevelopatotherplantsbeforeitwouldbeevidentatGinna.28 USTRDOESIGhlBERVICEG, INCYDATESUBJECTKD.BYDATE~4FC.SECT.SHEET~OFFEOJ.HO.8369q9cDQ0.

FXGURE4-2RACE-BASE SUPPORT WOW~Elch'usts~

.1C~ss-sacr/oYY'pvw.

s/zs)FIGURE4-3U6f5,DD1:-0I0N6L.F4Vt4:Lf),IP4AeBY/+~rt.DATE ei~/e."I!OJECI CHKD.BY~~~'ATEM4-..-++..

~t..~.mata.Dle,tee,Pf!O.l.tt~]..PyrEzo/gg~yg%F2~~z%F.(dAPjAo1lA.ILT~(OFTw4&//~/=cex)Poiso//

.(062/VyJIJI.)

/NSER7BALL.o/gg,ZC'aWo6o8BO~DdS/C~PE)Vo/MAZEÃ.02g FIGURE4-4POISONASSEMBLYINSTALLATION IIlJIICVFlg0lA~Q0C4I~I((III)li~~lIIl,8VcoC4r8 UBTG0QCUIQNBf:AVI(t.L',lf.'i.~W,w//,FIGURE4-5Dy~~~DA'rc14',+/3:.uoil ciGill(D.BYg';D*tEi~/!<g'e>/PIOOCOHSOLIDA77&rv'R'SS-DEC 7CPA~FULLY-SiZEDJ6,tlat:oF96'BgPQ~DMAILc".{z382llo~~

(@ZZZZe,g~<PWax

~'~~+(o7ellorn) fI/X)r~.SF'7PFueLRes,((Of'ZAai)Oy~)o.5F:!()'(-(((iITS'FUELRos3.QQ3.8ffhi'All.

)~8044U7.846(7:8268/dA)

PROJECT.8369DlRECTICNCF.LOADloIO83IMHrf4M~Hrn7//12II12)~-Fhoriz2'/Fvcrt~FhorizFvtrtFIGURE4-6FINITEELEMENTREPRESENTATION FlGURE4-7RACKWELDSEAST-LIEST

PLANE, UQTLDDCGIGNsERVICEG)

INcFIGURE4-8RACENELDSNORTH-SOUTH PLANEp/Pic4Du/Sredg~c7rdpr FIGURE4-9RACK-BASE SUPPORT 5.CostBenefitAssessment

~~~Thecapacityofthespentfuelstorageracksintheircurrentconfiguration is595fuelassemblies.

Atthecompletion oftheSpring,1984refueling outage332fuelassemblies willbestoredinthepool.Assumingfutureaveragereloadsizesof28fuelassemblies fullcoredischarge capability wouldbelostaftertheSpring1990refueling outage.Rochester GasandElectricalsohas81fuelassemblies storedatwhatwasformerlytheNuclearFuelServicesfacilityatWestValley,NewYork.RG&EisrequiredbythestateofNewYorktohavethisfuelremovedfromWest,ValleybySeptember, 1985.Theadditionofthisfueltothestoragepoolwouldcausealossoffullcoredischarge capability afterrefueling intheSpring1987.Withtheproposedmodification, 420storagelocations wouldbeadded.Attheprojected averageof28fuelassemblies discharged attheendofanannualcycleintheSpringofeachyear,thelossoffullcoredischarge capability wouldoccuraftertheSpring,2002refueling outage.ItistheintentofRG&Ethatthismodification extendthecapability tostorespent.fuelattheGinnasiteuntilafinalrepository isavailable inaccordance withtheinterimstorageprovisions oftheNuclearWastePolicyActof1982.Itisexpectedthatadisposalfacilitywillbeavailable andshipments willbeginby.themidtolate1990's.RG&E'ssolecontractural arrangement forthestorageofspentfueliswiththeNewYorkStateEnergyResearchandDevelopment Authority (NYSERDA) coveringthe81fuelassemblies atWest29

Valley,NewYork.NYSERDAhasdemandedthefuelberemovedand~~~inaccordance withtheContract, RG6Emustcomply.TheattachedTable5-1and5-2,providesinformation onscheduleofprojected fueldischarges andcorecomponents storedintheSFP.Adiscription o'fthemodification isatSection1ofthisattachment.

Preliminary estimates ofthecostsofthemodification areoutlinedbelow.Engineering Construction MaterialInstallation AFDCContingency Total125,000500,000825,00050,000400,000$1,900,000 Thisisequivalent toabout$4500perstoragelocation(or$13perkgU).Theseestimates arepreliminary andwillbeupdateduponrequest.Thealternatives toincreasing thecapacityofthespentfuelpoolarefew.Thereisnofuelreprocessing facilityavailable nowandnoindication thatonewouldbeavailable duringthisdecade.Therearenogovernment operatedaway-from-reactor storagefacilities.

Independent spentfuelstorageexistsonlyintheGeneralElectric, Morris,Illinoisfacility.

Thisisnotgenerally available tonon-G.E.customers norisitcurrently available tonewcustomers.

Costsfortransport ofonefuelassemblyalone,assumingathreedayturnaround timeanda600/miletriponeway,wouldbeontheorderof$10,500perfuel30 assemblyor$30/KgU.Theannualchargetostoreth'efuelandlaborandmaterialcostsforloadingandunloading wouldbeadditional.

Anotheralternative, thatofshippingtoanother.reactorsiteisnotavailable toRG&EbecausethecompanyoperatesonlytheGinnaNuclearPlant.Shuttingdownthereactorasanalternative toincreasing spentfuelstoragecapacitywouldimposeafinancial hardshiponthecustomers ofRG&E.TheGinnaPlantsuppliesapproximately 45percentofRG&E'selectricgeneration.

Thereplacement powercostswoulddependonwhethercompanycoalfiredgeneration wasavailable topickuptheload.Estimates rangefrom$23perMWHto$45/MWHforincremental costsofreplacement power.Thisisequivalent toabout$280,000to$540,000perday.Intermsofthematerialresources requiredtocompletethemodification, theamountneededislowrelativetothatrequiredtoeitherreplacethestorageracksentirelywithallnewhighdensityracks,orusedrystoragecasktechnology.

Asdiscussed inSection1,themodification consistsofremovingthelead-insandguidefunnelsfromthewaterboxes,addingbottomplatestotheformerwaterboxes,andrightangledboraflexpoisoninsertswithSS-304fillerplatesandliners.Table5-3liststhematerialrequirement forthemodification.

InReferences 3and4,theadditional heatloadsthatwouldbeanticipated assumingnormaldischarges uptoanendofplantlifein2009werecalculated.

Thisanalysis(Reference 4)assumednormalannualdischarges of36fuelassemblies 100hoursafter31 reactorshutdown.

Theresulting heatloadsfornormaldischarges 6werecalculated toincreaseincrementally from7.07x10BTU/HRxn1981to9.96x10BTU/HRintheyear2010.Byincreasing thecoolingtimeto14daysinthecaseofafullcoredischageinyear2010thedecayheatloadonthespentfuelpoolcoolingsystemwillremainbelow16x10BTU/HR.Atthismaximumheatload,theanalysisconcluded that,assuming80'Fservicewaterwithaflowrateof1600gpm,themaximumpooltemperature wouldbe150'Fandtheincreaseinservicewatertemperature wouldbewithintheenvironmental guidelines of20'F.Thepotential foranincreaseintheheatreleasedtotheenvironment duetothemodification istheincrement from7.07x10BTU/HRto9.96x1066BTU/HRorabout3xlOBTU/HR.Duringtheassumednormaloperation 6ofcoolingsystem(80'FservicewaterI1000gpm)thisincrement

'Irepresents abouta6'Fincreaseinservicewatertemperature throughtheheatexchanger.

Asstatedaboveevengiventhemaximumheatloadforafullcoredischagethe20'Fenvironmental guideline fortotalplantdischarge wouldbemet.32 Table5-1ScheduleofAnticipated FuelDischarges MonthearCapacityRemaining

~Existin~ProosedMarch1984March1985*Sept1985March1986March1987March1988March1989March1990March1991March1992March1993March1994March1995March1996March1997March1998March1999March2000March2001March20022828812828282828282828282828282828282828332360441469497525553581609637665693721749777805833861889917263235154126**98704214683655574546518490462434406378350322294266238210182154126**98*81fuelassemblies fromWestValley**Lossoffullcoredischarge capability 33 Table5-2Non-FuelComponents StoredinSFP*ControlRodAssemblies BurnablePoisonRodsThimblePluggingDevicesPrimary/Secondary Sources19*After1984refueling ComonentTable5-3MaterialVolumeWeicehtBottomPlates(420)NeutronPoisonSS-304Boraflex.020gm/cc12,259in310126,819 in~3minB3555lbs7990lbsLinerPlates(840)SS-304FillerPlates(,3360)SS-30424,619in135,804in7140lbs39,383lbs 6.RadioloicalEvaluation TheSFPpurification systemconsistsofademineralizer andfilter.Asurfaceskimmersystemconsisting ofapumpandfilterisalsousedtomaintainwaterclarity.Presently thedemineralizer generates 28cubicfeetofsolidwasteannuallyfromtworesinbedchanges.TheSFPfilterandskimmerfilterarechangedannuallygenerating 7cubicfeetofwaste.Thisrepresents approximately 0.3%oftheaveragesolidradioactive wastevolumegenerated, eachyear.SincethepreviousSFPrackmodification wascompleted in1977,thenumberofspentfuelassemblies storedhasincreased from92to302asof1983foranaverageincreaseof30peryear.From1977through1983,thewastevolumegenerated bytheSFPhasremainedthesame,whilethenumberofstoredspentfuelassemblies increased afactorof3.28.Evenifthegenerated solidradioactive wasteincreases

linearly, whichithasnot,withthenumberofspentfuelassemblies intheSFP,thesolidwastewouldincreasebyafactorof.2.96with894assemblies intheSFP(tomaintainfullcoredischarge capability only1015-121=894 fuelassemblies canbestoredintheSFP).Thesolidwastegenerated bytheSFPwouldthenbelessthan1%ofthetotalyearlygenerated solidradioactive waste.Thefuel.storageareaventilation iscombinedwiththeauxiliary andintermediate buildingventilation.

TheKr-85measuredinthissystemwas9.9curiesin1982and15.7curiesin1983.Allofthekr-85measuredcouldbeattributed tothereleaseofdecayedwastegastanks.35 Thetablebelowprovidestheresultsofarecentgammaisotopicanalysis(Nov.22,1983)oftheGinnaSFPwater,andidentifies principal radionuclides andtheirrespective concen-trations.

Valuesobtainedfromtheanalysisarerepresentative bothintermsoftypicalgrossradioactivity, andtherelativeconcentrations ofmajorradionuclides presentinthepoolwater.~IsoteConcentration CiccPercentContribution

.ToTotalWaterActivitCs-137Cs-134Co-60Co-587.7E-52.9E-52.1E-35.8E-531933SincethepreviousSFPrackmodification in1977,doseequivalent ratesaboveandatthesidesofthepoolhaveremainedthesame,between1and2mrem/hour.

Thedoseequivalent rateabovetheSFPcanalsobedetermined fromthefollowing model.Theradiation doseratefromtheSFPatapointabovethepoolsurfacewascalculated fromtheeffective watersurfaceactivity, allowingforself-absorption bythewatermediuminwhichtheisotopeswereassumedtobeuniformly mixed.DosemodelsusedwerethosebyCember(1969)*.Thebasicgeometryappliedinthecalculations consistsofamodifiedplanesourcecl&asshownbelow.P(h*Cember,H.,Introduction toHealthPhsics,Chapter10,PergamonPress(1969).36 TheequationforthedoserateDatpointPlfromaplanarsourcesimilartotheaboveis:RD..IixCaix211rdr=IIxIixCaixr+h1nR~+~hwhere:D.=doserate(rem/hr)oftheiisotope3.Ii=gammasourcestrengthofiisotope.th(rem/hrat1m/Ci)C~=effective su@aceactivity(Ci/m)ofiisotopeR=radiusofsource(m)h=distanceabovesourcealongcentralaxis(m)Inthefuelpooldosecalculations, thepoolsurfacewasconservatively assumedtohaveadiscconfiguration whoseradiusequaledonehalfthelongestactualpooldimension.

Sincethepoolcontaining mixedradioactivity morecloselyresembles alargeslabsource,Equation1wasmodifiedtoaccountforthepooldepth(t),-themixedradionuclide concentration C(Ci/m),andtheattenuation coefficient ofthepoolwater-1p(m).Thepoolsurfaceactivityduetoradioactivity inthelayerdxatadepthofxis:d(C.)=C'x'"Integrating Equation(2)overthetotal-thickness tgivestheeffective surfaceactivity:

(2)tCaiCrixe"dx=Cri(1-e")0V(3)37 Bysubstituting Equation3intoEquation1,thefollowing relationship isobtainedforcalculating doserate:D(rem/hr)

=ZDi=ZnliCri(1-e")VR2+h2~hThisequationgivesthedoseratesatthecenterofthepoolwherepersonnel wouldexperience thehighestradiation levelsfromthewater.Thedoseratescalculated forthenuclideslistedonthetablebelowarelessthan5mrem/hr.Doseratesattheedgeofthepoolwouldbeslightlylessthanthedoseratesat.thecenterofthepoolbecauseofthesmallerradiation contributions fromoneside.Routineradiation surveysperformed inthespentfuelpoolareahaveconfirmed thatdoselevelsatthepooledgearenotinexcessofthoseatthecenter.Thetablebelowgivestheresultsofanalysesperformed in1983todetermine theprincipal airborneradionuclides andtheirrespective concentrations inthespentfuelpoolarea.~jsotoeI-131I-133H-3Cs-134Cs-137Co-58Co-60~cicc<1E-12<1E-125.0E-07<1E-13<1E-13<1E-13<1E-13Theannualradiation dosetoaspecified organfrominhalation ofradioactive materialiscalculated usingthefollowing relationship:

38 Dose=365(C(Rb(DCF)where:Dose=annualdose(mrem/yr) 365=unitsconversion constantC.=airborneconcentration ofisotopei(pCi/cc)Rb,=assumedbreathing rate(cc/d)DCF.=doseconversion factorrelatingorgandosetointakeofanisotopebyinhalation (mrem/pC.).

lValuesforDCF.arebaseduponICRPrecommendations 1(ICRPPublication II,1959)andarecalculated inthefollowing manner:iDCFiwhere:ref(Cf)(2.0E+7)(365)

Df=ICRPrecommended maximumpermissible dosetoaspecified organofanadultoccupationally exposedtoradiation (mrem/yr)

Cf=ICRPrecommended concentration ofanisotopeinairwhich,ifbreathedbyanadultattherateof2.0E+7cc/dayfor50years,willresultina50th-year doseofDmremtothespecified organ(pCi/cc)2.0.E+7=adult.breathing rateassumedinICRPcalculations (cc/day)365=unitsconversion constant(days/yr)

WhereICRPIIgivesnovaluesofCfforcertainreforgans,thelowestvalueofCflistedforotherorgansistakenrefasthevalueofCffortheunlistedones.Foraddedconservatism, refthoseisotopeswhoseconcentrations werereportedas"lessthan"values,wereassumedtobepresentatdetection limitlevels.39 Sinceindividuals willspendonlyaportionoftheirtimeinthespentfuelpoolarea,dosesareexpectedtobeconsiderably lessthanifcontinuous exposureisassumed.Ifa100-hourannualoccupancy timeisassumedforamaximally exposedworkerinthespentfuelpoolarea,theresulting totalbodyandorgandosesarelessthan10mremperyear.Thespentfuelpoolmodification willresultinlongertermstorageofwellcooledfuel.Thepresentpooltemperature limitations willstillapply.Theoperation ofthepoolpurifi-1cationsystemandthebuildingventilation equipment willnot,change.Therefore, thepresent,airborneisotopicconcentrations arenotexpectedtochangesignificantly afterthemodification.

Thus,resulting potential doseincreases bothinthespentfuelpoolareaandanyoffsitelocations willbequitesmall.Thepotential increaseinannualman-remfrommorefrequentresinand'filterchangeswasestimated byscalingpresentpersonnel exposurevalueslinearlywiththenumberoffutureaddedspentfuelassemblies inthepool.Spentfuelpoolfiltercartridge anddemineralizer resinchangesassociated withtheexisting302storedfuelassemblies contribute lessthan0.1percentofGinna'stotalannualman-remburden.Iffilterandresinchangefrequencies areconservatively assumedtoincreaselinearlywithincreased numbersofassemblies inthepool,resultant personnel exposures couldberaisedbyafactorof2.96,ortolessthan0.3percentofGinna'stotalannualman-rem.Thus,increases inoccupational dosesfromtheserelatedoperations, whencomparedtotheplant'stotalyearlyexposureburden,willbenegligible.

40 Routineradiation surveysoftheGinna.spent fuelpoolhaveshowndoseratestypically lessthan5mR/hralongthepooledges.Notrendisapparentinpastandcurrentsurveydatawhichwouldreflectdoserateincreases fromcrudbuildup.Further,nofutureincreases inradiation levelsfromcrudinthepoolareanticipated asaresultofadditional fuel.Shouldaccumulation alongthepoolwallsbegintoproducehigherexposures ofanysignificance, thesewillbeindicated byroutineradiation surveys.Atthattimemethodswillbedeveloped toreduceradiation levelsatthepooledgetoaslowasisreasonably achievable.

Baseduponaveragepersonnel occupancy timesinthefuelpoolarea,theannualman-remresulting fromallrelatedoperations isestimated tobelessthanonepercentofthetotalplantman-rem.Futuretotaloccupational exposureatGinnaisnotexpectedtobesignificantly affectedbyeithera)morefrequentchangingofdemineralizer resinandfilters,orb)crudbuildupalongthesidesofthepool,asaresultoftheproposedspent.fuelpoolmodification.

Radiation doseratesabovethepoolresulting fromsubmerged spentfuelassemblies placedinanyconfiguration willbenegligible whencomparedtobackground.

Thecontribution fromthissourcetototalannualpersonnel exposureistherefore negligible.

Theradiation protection programwillutilizeroutinesurveyinformation todetermine changesinSFParearadiation levelsandairborneradioactive materialconcentrations tomain-tainpersonnel exposureALARA.

AsstatedinSection1,themodification ofthestoragerackswillincluderemovaloftheleadinguidesoverthewaterboxesandtheseismicsupportsbetweenthesupportbasesandthepoolwalls.Thesetwocomponents arefabricated fromSS-304andrepresent thewastematerialthatwillbeproducedbythemodifi-cation.Thetotalweightofthismaterialisapproximately 8000lbs.Thismaterialwillbedisposedofaseitherlowlevelradioactive wasteordecontaminated anddisposedofasnormal(non-radioactive) waste.

~~7.AccidentEvaluation Currently GinnaTechnical Specifications prohibitthemovementofaspentfuelcaskwiththeauxiliary buildingcrane.RG&Ehassubmitted anapplication todeletethisrestriction baseduponaproposedmodification tothecranetomeetthesingle-failure-proof requirements ofNUREG-0554~~.

Modifying thecranetobesingle-failure-proof wouldobviatetheneedtoanalyzethecaskdrop.Forthoseloadsthatcannotbemovedinasinglefailureproofmode,RG&Ewillcontinuetosatisfytherequirements ofNUREG-0612 bysomecombination ofloaddropanalysis, loadheightrestriction andsafeloadpath.Ineithercase,theGinnaTechnical Specification prohibits thetrolleyoftheauxiliary buildingcranetobestationed aboveorpassoveraspentfuelstoragerackcontaining spentfuel.Thisrequirement alongwithinstalled interlocks preventsthemovementofloadsoverspentfuelbytheauxiliary buildingcrane.Theoverheadhoistattachedtospentfuelpoolbridgeisusedtotransferspentfuelwithinthepoolarea.Useofthishoistislimitedtosinglefuelassemblies andtheirhandlingtools.Therackstructure protectsstoredfuelfromtheimpactofadroppedfuelassembly~.

Aweightlimitation onthehoist(2000lbs),thephysicalpositionoftheoverheadhoist,andanup-stoplimitswitchpreventsthepotential impactenergyofaloadfromsubstantially exceeding thatofadroppedspentfuelassembly.~

References l.Application forAmendment toOperating License,January30,1976.2.Letter,ASchwencer toL.D.White,November15,1976.3.Zetter,L.D.WhitetoD.L.Ziemann,February13,1980.4.Zetter,D.M.Crutchfield toZ.D.White,November3,1981.5.Application forAmendment toOperating License,February23,1982.6.Application forAmendment toOperating Zicense,January18,1984.7.Letter,J.E.MaiertoD.M.Crutchfield, June9,1981.8.9U.S.NuclearRegulatory Commission, StandardReviewPlan3.7.2"SeismicSystemAnalysis,"

Revision1,July,1981.Fritz,R.J.,"TheEffectsofLiquidsontheDynamicMotionsofImmersedSolids,"ASMEFebruary, 1972.10.Dong,R.G.;"Effective MassandDampingofSubmerged Structures",

UCRL-52342, L.L.L.,April,1978.ll.Stokey,W.J.,Scavuzzo, R.J.andRadke,E.E.,"DynamicFluidStructure CouplingofRectangular ModulesinRectangular Pools,"ASMESpecialPublication PVP-39,1979.12.Regulatory Guide1.61,"DampingValuesforSeismicDesignofNuclearPowerPlant",October,1973.13.Rabinowicz, E.,"Friction Coefficients ofWater-Zubricated Stainless SteelsforaSpentFuelRackFacility",

Studyperformed forBostonEdison,Co.November, 1976.14.ASMEBoilerandPressureVessels,NUCZEARVESSELS,SectionIII,1980ed.15.G.E.Technical Paper22A5866,Rev.Dec.26,1979.AppendixII,FUELASSEMBZYSTRUCTURAL CHARACTERISTICS.

16.R.D.Blevins,Ph.D,FORMULAS, FORNATURALFREQUENCY ANDMODESHAPE,VanNostrandReinholdCo.,N.Y.,N.Y.,1979.17.,R.J.Roark,W.C.Young,FORMULASFORSTRESSANDSTRAIN,MCRAW-HILZ BOOKCO.,N.Y.5thEd.,1975.

18.J.S.Anderson, "Boraflex NeutronShielding Material-ProductPerformance Data,"BrandIndustries, Inc.,Report748-30-1, (August,1979).19.J.S.Anderson, "Irradiation StudyofBoraflexNeutronShielding

,Material,"

BrandIndustries, Inc.,Report748-10-1, (July,1979).20.J.R.Anderson, "AFinalReportontheEffectsofHighTemperature BoratedWaterExposureonBISCOBoraflexNeutronAbsorbing Material,"

BrandIndustries, Inc.,Report748-21-1, (August,1978).21.O.W.Blodgett, DesignofWeldedStructures, J.F.LincolnArcWeldingFoundation, Cleveland, Ohio,7thPrinting1975.22.AmericanConcreteInstitute, ManualofConcretePractice, 329-32,Detroit,Michigan.

23.LetterT.R.RobbinstoJ.D.Cook,March15,1984.24.GilbertAssociates, Inc.,GinnaStationSeismicUpgrading Program-Auxiliary Structures SeismicAnalysis, May15,1980.25.Application forAmendment toOperating License,January18,1984.

ForU.S.Tool4Die,?nc.Criticality AnalysisofRegion2oftheGinnat<DRSpentFuelStorageRackFinalReportbyPickar4,Lowe4Garrick,Inc.Mashington,D.C.

TABLEOFCONTENTS1.0THEMAXIMUMDENSITYRACK(MDR)DESIGNCONCEPT1.1Introduction

2.0 CRITICALITY

ANALYSISOFREGION2(ASSUMESIRRADIATED FUEL)2.1Analytical Technique 2.2Calculational Approach2.3Manufacturing andThermalConsiderations 2.4DesignConservatisms 2.5AccidentAnalysis2.6RequiredExposureasaFunctionofInitialEnrichment forRegion2SpentFuel~Pae3891011REFERENCES 137047U012784 TABLEOFCONTENTS(continued)

ListofTablesTable10TitleRegion2DesignCriteriaFuelAssemblyTechnical Information forGinnaNuclearPlantSummaryofLeopardResultsforMeasuredCriticals Westinghouse UO2Zr-4CladCylindrical CoreCriticalExperiments BattelleFixedNeutronPoisonCriticals SaxtonPu02-U02CriticalExperiments ESADAPu02-U02CriticalExperiments SummaryofPredictions forkeffinCriticality Experiments SummaryofReactivity BiasesandUncertainties forGinnaRegion2MDRComputedInfiniteMultiplication FactorsforGinnaMDR7047U012784

TABLEOFCONTENTS(continued)

ListofFiures~Ffere101213TitleGinnaMDRSpentFuelRackDesignNetDestruction ofU-235VersusBurnupin,theYankeeAsymptotic t/eutronSpectrumSpecificProduction ofU-236VersusBurnupinYankeeAsymptotic NeutronSpectrumNetDestruction ofU-238VersusBurnupintheYankeeAsymptotic NeutronSpectrumSpecificProduction ofPu-239VersusBurnupinYankeeAsymptotic NeutronSpectrumSpecificProduction ofPu-240VersusBurnupinYankeeAsymptotic NeutronSpectrumSpecificProduction ofPu-241VersusBurnupinYankeeAsymptotic NeutronSpectrumSpecificProduction ofPu-242VersusBurnupinYankeeAsyhptotic NeutronSpectrumSpecificProduction ofTotalPuandFissilePuVersusBurnupinYankeeAsymptotic NeutronSpectrumAtomPercentofTotalUVersusExposurePu-239/U-238 AtomRatioVersusExposureAtomPercentofTotalPuVersusExposureFissionProductAbsorption Cross-Sections asaFunctionofTimeAfterShutdown141516One-Quarter RackCellModelforGinnaMDRFour-Quarter RackCellModelforGinnaMDRVariation ofkwithAssemblyPitchforGinnaMDR17Variation ofkwithSteelThickness forGinnaMDR7047U012784 TABLEOFCONTENTS(continued)

ListofFiures~Fiure18TitleVariation ofkwithPelletDiameterforGinnaMDR19.Variation ofkwithPelletDensityforGinnaMDR20212223Variation ofkwithWaterDensityforGinnaMDRVariation ofkwithTemperature forGinnaMDR.Configuration UsedtoDetermine theEffectsoftheRegion1-Region2Interface RegionsofAcceptability andUnacceptability forRegion2SpentFuel7047U012784 1.0THEMAXIMUMDENSITYRACK(MDR)DESIGNCONCEPT1.1Introducti onHistorically, spentfuelrackdesignshavebeenbasedonconservative assumptions thatcouldbeeasilyaccommodated sinceitwasnotplannedtostorelargenumbersofhighexposurespentfuelassemblies on-site.Previously itwasanticipated thatonly.small.amountsofhighexposurefuelassemblies (1/4to1/2ofafullcoreload)wouldnormallybestoredinthespentfuelpoolatanyonetime.Additionally, itwasanticipated that,occasionally (e.g.,forinservice inspection ofthereactorvesselinternals) theentirecorewouldbeunloadedandtemporarily storedinthespentfuelpool.Therefore, thespentfuelstoragerackdesignwasbasedontheconservative assumption thatallfuelrackstoragepositions wouldbeoccupiedbyfreshunirradiated fuelassemblies ofthehighestinitialenrichment thatwasforeseenasbeinguseableinthatfacility.

Thepenaltyinachievable.

spentfuelstoragedensityassociated withthisconservative designassumption wasrelatively smallunderthecircumstances anticipated andeasilyaccommodated byaconservative spentfuelrackdesign.Thepotential penaltyassociated withthisconservative designbasisisnolongersmallwhenlong,termon-sitestorageofspentfuelisanecessity.

Itisnotconceivable thatmorethanonefullcoreloadoffreshunirradiated fuelassemblies couldbestoredinthespentfuelstoragepool.Therefore, itisunnecessary andwastefultobasetheentirespentfuelstoragerackdesignontheassumption offreshunirradiated fuelofthehighestinitialenrichment.

IntheMDRdesignconcept,thespentfuelpoolisdividedintotwoseparateanddistinctregionswhichforthepurposeofcritically considerations maybeconsidered asseparatepools.Suitability ofthisdesignassumption regarding poolseparatabi lityisassuredthroughappropriate designrestrictions attheboundaries betweenRegion1andRegion2.Thesmallerregion,Region1,ofthepoolisdesignedonthe7043U012784 basisofcurrently acceptedconservative criteriawhichallowforthesafestorageofanumberoffreshunirradiated fuelassemblies (including afullcoreunloading ifthatshouldprovenecessary).

Thelargerregionofthepool,Region2,is'esigned tosafelystoreirradiated fuel.assemblies whichwillbedischarged fromthereactorinlargequantities.

ThecriteriaforRegion2ofthepoolarespecifically listedinTableTheonlychangeincriteriaistherecognition ofactualfuelandfissionproductinventory accompanied byasystemforcheckingfuelpriortomovinganyfuelassemblyfromRegion1toRegion2.Duringanormalrefueling operation, eachfuelassemblyisfirstmovedfromthecoretoRegionl.Aftertherefueling operation iscompleteandthesuitability ofeachspentfuelassemblyformovementintoRegion2isverified, thisfuelwillbemovedintoRegion2.Region2isdesignedtostorefuelwhichdoesnotexceedpre-established reactivity criteria.

Consequently, thelimitonacceptable initialenrichment varieswiththeexposureatthetimeofstorage.Forinstance, 4.25w/ofuelisacceptable forstorageonlyafterapredetermined minimumexposurehasbeenreached.Asomewhatlowerminimumexposurewouldbeacceptable forfuelwithalowerinitialenrichment.

Thisresulting curveofinitialfuelassemblyenrichment versusminimumacceptable exposuredefinesacurveofconstantspentfuelrackreactivity'.

Themajorpurposeofthisstudyisthedetermination ofthiscurve.2.0CRITICALITY ANALYSISOFREGIO)$2(ASSUMESIRRADIATED FUEL)Thefuelassemblies usedinthisanalysisarecharacterized inTable2.TheGinnaasbuiltspentfuelrackcellisshowninFigure1.Thefollowing discussion summarizes thedesignofthespentfuelrackswithrespecttothecriticality design.Theanalytical techniques described herearesimilartothoseusedtosuccessfully licensespentfuelracksforseveralotherplants.7043U012784 2.1AnalticalTechniueTheLEOPARDcomputerprogramwasusedtogeneratemacroscopic crosssectionsforinputtofourenergygroupdiffusion theorycalculations whichareperformed withthePDg-7program.LEOPARDcalculates the(2)neutronenergyspectrumovertheentireenergyrangefromthermalupto10Mevanddetermines averagedcrosssectionsoverappropriate energygroups.Thefundamental methodsusedintheLEOPARDprogramarethose-usedintheNUFTandSOFOCATEprogramswhichweredeveloped (3)(4)undertheNavalReactorProgramandthusarewellfoundedandextensively testedtechniques.

Inaddition, Westinghouse ElectricCorporation, thedevelopers oftheoriginalLEOPARDprogram,demonstrated theaccuracyofthesemethodsbyextensive analysisofmeasuredcriticalassemblies consisting ofslightlyenrichedUOfuelrods.(5)Inaddition, Pickard,LoweandGarrick,Inc.(PLG)hasmadeanumberofinprovements totheLEOPARDprogramtoincreaseitsaccuracyforthecalculation ofreactivities insystemswhichcontainsignificant amountsof.plutonium mixedwithU02.PLGhastestedtheaccuracyofthesemodifications byanalyzing aseriesofUOandPu02-UOcriticalexperiments.

Thesebenchmarking analysesnotonlydemonstrate theimprovements obtainedfortheanalysisofPu02-U02systemsbutalsodemonstrate thatthesemodifications havenot'adversely affectedtheaccuracyofthePLG-modified LEOPARDprogramforcalculations ofslightlyenrichedU02systems.TheU02criticalexperiments chosenforbenchmarking includevariations inH20/U02volumeratios,U-235enrichments,,

pelletdiameters andcladdingmaterials.

AlthoughtheLEOPARDmodelalsoaccurately calculates'he reactivity effectsofsolubleboron,theseexperiments havenotbeenincludedintheLEOPARDbenchmarking criticals sincethespentfuelpoolcalculations donotinvolvesolubleboron.Neutronleakagewasrepresented byusingmeasuredbucklinginputtoinfinitelatticeLEOPARDcalculations torepresent thecriticalassembly.

AsummaryoftheresultsisshowninTable3forthe27measuredcriticals chosenasbeingdirectlyapplicable forbenchmarking 7043U012784 theLEOPARDmodelforgenerating groupaveragecrosssectionsforspentfuelrackcriticality calculations.

Theaveragecalculated keffis0.9979andthestandarddeviation fromthisaverageis0.0080hk.Reference 5raisedquestions concerning theaccuracyofthemeasuredbucklingreportedfortheexperiments number12through19.Ifthesedataareexcluded, theaveragecalculated kefffortheremaining 19experiments is1.0006withastandarddeviation fromthisvalueof0.0063hk.Inalloftheseexperiments; therearesignificant uncertain-tiesinthemeasuredbucklings whicharenecessary inputstotheLEOPARDanalysis.

Theseuncertainties arethesameorderofmagnitude astheindicated errorsintheLEOPARDresults,andtherefore amoredefinitive setofexperimental dataisusedtoestablish theaccuracyofthecombinedLEOPARD/PDg-7 modelusedforthecriticality analysisofth'spentfuelracks.ThePDgseriesofprogramshavebeenextensively developed andtestedoveraperiodof20yearsandthecurrentversion,PDg-7,isanaccurateandreliablemodelforcalculating thesubcritical marginoftheproposedspentfuelrackarrangement.

Thiscodeoramathematically equivalent methodisusedbyalltheU.S.suppliers oflightwaterreactorcoresandreloadfuel.Inaddition, thiscodehasreceivedextensive utilization intheU.S.NavalReactorProgram.Asaspecificdemonstration oftheaccuracyofthe'calculational modelusedforthespentfuelrackcalculations, thecombinedLEOPARD/PDg-7 modelhasbeenusedtocalculate fourteenmeasuredjustcriticalassemblies.

Thecriticals arehighneutronleakagesystemswithalargevariation inU/H0volumeratioandincludeparameters inthesame2rangeasthoseapplicable totheproposedfuelrackdesign.Experiments including solubleboronareincludedinthisdemonstration sincetheabilityofPDg-7tocalculate neutronleakageeffectsisofprimaryinterest.

Theuseofsolubleboronallowschangesintheneutronleakageoftheassemblywhilemaintaining auniformlatticeandthusallowsabettertestoftheaccuracyofthemodel.Furthermore, iteliminates theerrorassociated withthemeasuredbucklings whichisinherentintheLEOPARDbenchmarks, thuspermitting determinations oftheactualcalcu-

lationaluncertainty whichmustbeaccounted forinthespentfuelrackcriticality analysis.

Thesecombination LEOPARD/PDg-7 calculations resultinacalculated averagekffof0.9928withastandarddeviation aboutthisvalueofeff0.0012hk.Theseresults,asshowninTable4demonstrate thattheproposedLEOPARD/PDg-7 calculational modelcancalculate thereactivity oftheproposedspentfuelrackarrangements withanaccuracyofbetterthan0.010Lkatthe95percentconfidence level.'IThecrosssectionsfortheBoraflexneutronabsorbing materialwhichisanintegralpartofthedesignarecalculated usingfundamental techniques thathavebeensuccessfully appliedinthepasttothinheavilyabsorbing mediumssuchascontrolrods.Thisprocedure isstraightforward andiscomprised ofseveralwelldefinedsteps:1.TheBfromthethinBoraflexsheetsishomogenized inanappropriate amountofwater,andLEOPARDisusedtoobtainunshielded macroscopic Bcrosssections.

2.Integraltransport theoryisappliedinslabgeometryusingThey'smethodforcalculating fluxdepressions andshielding factorstodetermine anappropriate Bnumberdensity.Thisapproachis10similartothatofAmouyalandBenoist.3.TheBnumberdensitycalculated inStep2ishomogenized inwater,andLEOPARDisusedtoobtaincorrected microscopic Bcrosssections.

4.Blackness theoryisappliedtoobtainmacroscopic crosssectionswhichwillproducetherequiredboundaryconditions atthesurfaceoftheBoraflexsheets.7043U012784 Inadditiontothefourteencriticalassemblies inTable4,theLEOPARD/PDg modelwasusedtocalculate thekefffortwelveadditional criticalassemblies, sevenofwhichincorporated thin,heavily-absorbing materials forwhichtheprocedure justdescribed wasusedtodetermine themacroscopic crosssections.

Thesetwelvecriticals wereperformed byBattellePacificNorthwest Laboratories specifically forthepurposeofproviding benchmark criticalexperiments insupportoFspentfuelcriticality analysis.

Theyaredescribed indetailinReference 18.Theresultsofthesecriticalexperiments aresummarized inTable5.Thefirstsevenofthesetwelveexperiments includefixedneutronpoisonabsorberplates,andtheaveragekffcalculated forthesejustcriticalassemblies was0.9935,withaeffstandarddeviation aroundthisvalueof0.0007b,k.Theotherfivecriticalexperiments inthisseriesdonotincludeabsorberplatesandtheaveragekffcalculated forthesejustcriticalassemblies waseff0.9944,withastandarddeviation aroundthisvalueof0.0007Lk.Theoverallaveragekffcalculated forthesetwelvejustcriticaleffassemblies was0.9939,withastandarddeviation aroundthisvalueof0.0008~k.-Thisextensive seriesofV02criticalexperiments furthersupportstheapplicability ofthemethodsdescribed aboveforuseincalculating thesubcritical marginofthesefuelstoragerackdesigns,anddemonstrates thattheaccuracyofbetterthan0.010hkatthe95percentconfidence levelestablished fortheLEOPARD/PDg-7 modelappliesequallywelltodesignsincorporating fixedneutronabsorbers forwhichblackness theoryisusedtocalculate themacroscopic crosssectionsandalsotoassemblies containing plutonium.

Asaresultofthisapproachtoseparately benchmark boththecrosssectionsandthediffusion theorycalculations againstapplicable criticalassemblies, the"transport theorycorrection factor"isimplicitly includedinthederivedcalculational uncertainty factor.7043U012784 Theanalytical methodsusedforRegion2mustalsoaccountforthedepletion ofU-235andbuildupofvariousplutonium isotopesandfissionproducts.

Theisotopiccomposition iscalculated asafunctionofirradiation time,assemblyaverageexposure, andsubsequent decayusingtheLEOPARD(-andCINDERcomputeprograms.

Oncetheisotopic(6)compositions ofthefuelassemblies areknown,thesubsequent criticality calculations forthespentfuelracksinRegion2areperformed inthemannergivenabove.Theaccuracyoftheexposuredependent isotopicconcentrations calculated withtheLEOPARDprogramisdemonstrated inFigure2throughFigure12.Figures2through9showcomparisons ofLEOPARDcalculated datawithmeasureddatafromaU02fuelassemblyirradiated intheYankee-Rowe reactorwhileFigures10through12showcorresponding dataforamixedoxide(Pu02-UO)fuelassemblyirradiated intheSAXTOWreactor.ExceptforthedatalabeledPLGcalculation, thedataandcurvesonFigures2through9andFigures10through12aretakendirectlyfromReferences 7and8,respectively.

Inallcases,theaccuracyofthecalculations labeledPLGiswithintheuncertainty inthemeasureddata.Theaccuracyofreactivity calculations forirradiated fuelcanbedemonstrated inpartbytheanalysisofcriticalarraysofmixedoxidefuelrodswhichcontainhighconcentrations oftheplutonium isotopes.

Tables6and7showresultsofcriticality analysesfortheSAXTON(9)andESADAsetsofexperiments whichcoverawiderangeofwater-to-oxide volumeratios.AsummaryofthesedataisshowninTable8Forthemixedoxidecriticalsthecalculated meankeffis09969withastandarddeviation aboutthisvalueof0.0066'hk.Usingthe95%probability at95%confidence levelcriterion (one-sided) with11datapoints,thisimpliesapossibleerrorof2.82=0.0186hkwithanoffsetof+.0031Lk.7043U012784 Theanalytical methodsusedforRegion2mustalsoaccountforthedepletion ofU-235andbuildupofvariousplutonium isotopesandfissionproducts.

Theisotopiccomposition iscalculated asafunctionofirradiation time,assemblyaverageexposure, andsubsequent decayusingtheLEOPARDandCINDERcomputerprograms.

Oncethe,isotopic(6)compositionsofthefuelassemblies areknown,thesubsequent criticality calculations forthespentfuelracksinRegion2areperformed inthemannergivenabove.Theaccuracyoftheexposuredependent isotopicconcentrations calculated withtheLEOPARDprogramisdemonstrated inFigure2throughFigure12.Figures2through9showcomparisons ofLEOPARDcalculated datawithmeasureddatafromaU02fuelassemblyirradiated intheYankee-Rowe reactorwhileFigures10through12showcorresponding dataforamixed-oxide(Pu02-UO)fuelassemblyirradiated intheSAXTONreactor.ExceptforthedatalabeledPLGcalculation, thedataandcurvesonFigures2through9andFigures10through12aretakendirectlyfromReferences 7and8,respectively.

Inallcases,theaccuracyofthecalculations labeledPLGiswithintheuncertainty inthemeasureddata.Theaccuracyofreactivity calculations forirradiated fuelcanbedemonstrated inpartbytheanalysisofcriticalarraysofmixedoxidefuelrodswhichcontainhighconcentrations oftheplutonium isotopes.

Tables6and7showresultsofcriticality analysesfortheSAXTONandESADAsetsofexperiments whichcoverawiderangeof(10)water-to-oxide volumeratios.AsummaryofthesedataisshowninTable8.Forthemixedoxidecriticals, thecalculated meankffis0.9969effwithastandarddeviation aboutthisvalueof0.0066Ak.Usingthe95%probability at95%confidence levelcriterion (one-sided) with11datapoints,thisimpliesapossibleerrorof2.82=0.0186Dkwithanoffsetof+.0031~k.7043U012784

Theothermajoruncertainty inthecalculations forRegion2isassociated withthecalculated reduction infuelassemblyreactivity associated withthedepletion oftheheavymetalsandtheaccumulation offissionproductsasafunctionoffuelassemblyexposure.

Asanexample,considera4.25w/o(initialenrichment)

Ginnafuelassemblyat30,000HND/HT.Thetotalreactivity lossfromthefreshunirradiated caseis0.225hk/k,ofwhichapproximately 50'Xcanbeattributed tothebuild-upoffissionproducts.

Calculations ofreactorreactivity lifetimes usingthesameanalytical methodsasusedinthisanalysisdemonstrate anaccuracyofbetterthan+5%.Therefore, theresulting uncertainty inthecalculated fuelassemblykassociated withfueldepletion wouldbeconservatively estimated at0.01126k/k(=.05x.235hk/k).The,corresponding uncertainty inthecalculated Region2multiplication factoris0.0102hkonabasecaseRegion2kof0.9072.Inordertoprovidefurtherassurance oftheconservative natureofthesecalculations, thedecayofa>>fissionproductsfollowing discharge ofthefuelassemblywastakenintoaccount.Thiswasaccomplished withtheaidoftheCIHDERcodewhichtreatsatotalof186nuclidesin84linearchains.Thefissionproductinventory foreachfuelassemblywasdecayedforthirtyyearsfollowing itsremovalfromthereactorcore,andthetimepointofminimumfissionproductabsorption withinthatthirtyyearperiodwasusedatthebasisforde'termining thefissionproducemacroscopic absorption crosssectionsforthatparticular fuelassemblyatthatspecificexposure.

Thatminimumoccursatapproximately 100daysintothedecayandfrom,thenoncontinues toincreaseasi>>ustrated inFiure13.Reduction inthefissionproductinventory duetoleakageorgure(>>)escapetotheplenumhasbeenfoundtobenegligible.

2.2CalculationalAroachThePOQ-7programisusedinthefinalpredictions ofthereactivity ofthespentfuelstoppageracks.Thecalculations areperformed infourenergygroupsandtakeintoaccounta>>thesignificant geometric detailsofthefuelassemblies, fuelboxes,andmajorstructural components.

The70430012784

geometryusedformostofthecalculations isabasiccellrepresenting one-quarter oftheareaofarepeating arrayofstainless-steel boxes.ThespecificgeometryofthisbasiccellisshowninFigure14.Thecalculational approachistousethebasiccelltocalculate thereactivity ofaninfinitearrayofuniformspentfuelracksandtoaccountforanydeviations ofth'eactualspentfuelrackarrayfromthisassumedinfinitearrayasperturbations onthecalculated reactivity ofthebasiccell.Theeffectsofmanufacturing tolerances, aswellasthermaluncertainties, including fuelandwatertemperature anddensityvariations, arealsotreatedasperturbations onthecalculated reactivity ofthebasiccell.TheAdequacyofthecalculational meshselectedforthistypeofcel'icalculation hasbeenverifiedbycomparison withtheresultsofanidentical geometrywhichusedafinercalculational mesh(twotimesthenumberofmeshintervals ineachdirection).

Thefinercalculational meshresultedinlittlechangeinthevalueofkwithanobservedincreaseof+0.0002Dk.Afurthercheckonthecalculational modeluseddivastheuseofamoreaccuratespatialmodelencompassing thecornersoffouradjacentrackcellsas'howninFigure15.Theuseofthismodelhadtheeffectofincreasing kby0.0005~k.2.3Manufacturin andThermalConsiderations Severalperturbations ofthebasiccellwereperformed todetermine theeffectsofchangesinthephysicalcellandcomponent dimensions, duetomanufacturing tolerances, changesinwaterdensity,andchangesintemperature.

Allcaseswereperformed on4.25w/ofuelatanexposureof30,000MWD/tonne.

7043U012784 Thefollowing changesinspecifications duetomanufacturing tolerances wereconsidered:

Reducingassemblypitchby.060"leavingotherdimensions constant(watergapreduced);

reducingsteelwallthickness ofbothbox(by.009")andboraflexretaining-device(by.003")(increased watergap);reducingpelletdiameter.0010",andincreasing pelletdensityby1.5%ofthetheoretical value.Thesevariations represent thefullrangeofpossiblevariations inthemechanical designofthefuelrackandfuel.Thereduction inpitchresultsinanincreaseinkof0.0019dk.Thereduction insteelthickness resultsinadecreaseofk~of0.0002hk.Thereduction inpelletdiameterresultsinadecreaseinkof0.0005hk,'hiletheincreaseinpelletdensityincreases kby0.0015Dk.TheseeffectsareshowninFigures16-19.Theresultsofdecreases inwaterdensityandincreases intemperature EareshowninFigures20and21.Inbothcases,itisclearthatthebasecase(68'F,wateratfulldensity)represents themaximumreactivity.

Theeffectoftheinterface betweenRegion1andRegion2wasevaluated assumingfresh4.25w/ofuelinRegion1and4.25w/ofuelatanexposureof30,000NWD/MTinRegion2.Thisresultedinacomputedkof0.9195,orachangeof+0.'0123Lkoverthecomputedkbasisrack.cellusedtorepresent Region2.ThemodelusedisshowninFigure22.Asummaryofthebiasesanduncertainties inthecomputedvalvesofkisgiveninTable9.Theuncertainties havebeencombinedstatistically.

Theseresultsshowthatabasiccellcomputedkoflessthan0.9108willassureanactualkbelow0.95with95%probability atthe95%confidence level.2.4DesinConservatisms MhilethetlDRconceptreducessomeofthedesignconservatisms inherentintheearlierspentfuelstorageconcepts(e.g.,assumption offreshunirradiated fuel),thedesignandanalysesfortheHDRasimplemented inRegion2arestillveryconservative innature.7043U012784 10 Theuseofassemblyaverageexposures isoneexampleofthisconservative approach; Axially,morethan80%ofthefuelassemblywillnormallyhavereachedexposures greaterthantheaverageandthiswilloccuralongthecentral,higherworthregionoftheassembly.

Thelowerexposureregionswouldnormallyaccountforlessthan20%ofthefuelassemblylengthdistributed attheendsofthefuelassemblyactivelengthwhicharelowerworthregions.Theresultisaneutronically higherexposureassemblythanrepresented bythesimpleassemblyaverageexposure.

Theuseofthesimpleassemblyaverageexposurecanresultinanover-estimate ofthefuelassemblykffby+.015hk/k.2.5AccidentAnalsisTheRegion2fuelracksaredesignedtopreventadroppedfuelbundlefrompenetrating andoccupying apositionotherthananormalfuelstoragelocation.

Theonlypositivereactivity effectofsuchabundleonthemultiplication factoroftherackwouldbebyvirtueofareduction inaxialneutronleakagefromtherack.Sincethecalculations reportedheretakenocreditforaxialneutronleakage,theeffectofadroppedfuelassemblycouldnotbeexpectedtoexceedthereportedmaximumpossiblereactivity ofthespentfuelstoragerack.Thisisbecausethereportedmaximumpossiblereactivity oftherackisbasedoninfinitearraycalculations (bothlaterally andvertically).

2.6ReuiredExosureasaFunctionofInitialEnrichment forReion2SentFuelAsshownabove,acomputedkof0.9108willassurethattheactualkisbelow0.95withaprobability of0.95atthe95%confidence level.Thesecomputations wereperformed for4.25w/ofuelwithanexposureof30,000tlWD/NT.Fotlowerenrichments withthesamecomputedvalueofk,theamountofexposurewillbereduced,reducingthereactivity uncertainties duetodepletion offuelandbuildupoffissionproducts, andthusreducingthetotaluncertainty.

Thusthecomputedkvalueof0.9108shouldbeconservative forallenrichments notexceeding 4.25w/o.In7043U012784 ordertoallowforpossibleinterpolation errors,however,atargetvalueof0.9050forkwillbeusedforotherenrichments.

TheresultsshowninTable-l0maybeinterpolated toestimatetherequiredexposuretoreachacomputedkvalueof0.9050.For4.25w/ofueltherequiredexposureis30,000HMT/MT,for3.00w/ofuelitis15,960HMD/MT.For1.75w/ofuel,evenfreshfuelhasacomputedkoflessthan0.9050.Theresulting curve,showninFigure23,givestherequiredexposureasafunctionofenrichment toassurethatthevalueofkinthespentfuelhasaprobability of95%ofnotexceeding 0.95>>atthe95'Xconfidence level.rBecauseofthewell-founded, conservative technique usedfordetermination oftheinfinitemultiplication factor,thereisassurance thatthisspentfuelrackdesignwill*notcauseunduerisktothepublichealthandsafetyresulting fromcriticality considerations.

7043U012784 12 REFERENCES 1.R.F.:Barry,"LEOPARD-ASpectrumDependent Non-Spatial Depletion CodefortheIBM-7094,"

MCAP-3269, September 1963.2.M.R.Caldwell, "PDg-7Reference Manual,"WAPO-TM-678, January1967.3.H.Bohl,E.GelbardandG.Ryan,"MUFT-4-FastNeutronSpectrumCodefortheIBM-740,"

WAOP-TM-72, July1957.4.H.AmsterandR.Suarez,"TheCalculation ofThermalConstants AveragedOveraWigner-Wilkins FluxSpectrum:

Description oftheSOFOCATECode,"MAPO-TM-39, January1957.5.L.E.Strawbridge andR.F.Barry,"Criticality Calculations forUniformMater-Moderated Lattices,"

NuclearScienceandEngineering, 23,58,1965.6.ElectricPowerResearchInstitute, "FissionProductDataforThermalReactors, Part1andPart2:DataSetforEPRI-CINDER andUsersManualforEPRI-CINDER CodeandData,"EPRIHP-356,FinalReport'1976).7.R.J.Ndvik,"Evaluation ofMassSpectometric andRadiochemical AnalysesofYankeeCoreIandCoreIISpentFuel,"MCAP-6068 (1965).8.R.J..Nodvik, "SaxtonCoreIIFuelPerformance Evaluation ofMassSpectometric andRadiochemical AnalysesofIrradiated SaxtonPlutonium Fuel,"WCAP-3385-56 PartII{1970).9.M.L.Orr,H.I.Sternberg, P.Oeramaix, R.H.Chastain, L.BinderandA.J.Impink,"SaxtonPlutonium Program,NuclearDesignoftheSaxtonPartialPlutonium Core,"MCAP-3385-51, December1965.(AlsoEURAEC-1490).

10.R.D.Learner,W.L.Orr,R.L.Stover,E.G.Taylor,J.P.TobinandA.Bukmir,"Pu02-U02 FueledCriticalExperiments,"

MCAP-3726-1, July1967.ll.R.A.Lorenz,etal.,"FissionProductReleasefromHighlyIrradiated LWRFuel,"NUREG/CR-0722, February1980.12.P.M.Davison,etal.,"YankeeCriticalExperiments Measurements onLatticesofStainless SteelCladSlightlyEnrichedUraniumDioxideFuelRodsinLightWater,"YAEC-94,Mestinghouse AtomicPowerDivision{1959).13.V.E.GrobandP.W.Oavison,etal.,"Multi-Region ReactorLatticeStudies-ResultsofCriticalExperiments inLooseLatticesofUORods1nM20,0MCAP-1412, Mest1nghoose AtomicPower01v141on(1960).7044U012784

'3 REFERENCES (continued) 14.W.J;EichandW.P.Kovacik,"Reactivity andNeutronFluxStudiesinMultiregion LoadedCores,"WCAP-1433, Westinghouse AtomicPower,Division(1961).15.'.J.Eich,PersonalCommunication (1963).16.T.C.Engelder, etal.,"Measurement andAnalysisofUniformLatticesofSlightlyEnrichedU02Moderated byDp0-H20Mixtures,"

BAW-1273, theBabcock&WilcoxCompanytl963).17.A.L.MacKinney andR.M.Ball,"Reactivity Measurements onUnperturbed, SlightlyEnrichedUraniumDioxideLattices,"

BAW-1199, theBabcock4WilcoxCompany(1960).18.BattellePacificNorthwest Labbratories, "Critical Separative BetweenSubcritical Clustersof2.35WtX235-UEnrichedU02RodsinWaterWithFixedNeutronPoisons,"

PNL-2438.

7044U012784 TABLE1REGION2OESIGNCRITERIA1.Actualirradiated fuelandfissionproductinventory isassumed.2.keff(0.953.Creditmaybetakenforpresenceofboratedwaterforabnormal(accident) conditions.

4.MultiplechecksrequiredforeachfuelassemblypriortotransferfromRegion1toRegion2.7044U012784 TABLE2FUELASSEMBLYTECHNICAL INFORMATION FORGINNANUCLEARPLANTRodArrayRodsPerAssemblyRodPitch,In.OverallDimensions, In.14x14gf1790.5567.784ActiveFuelHeight,'n.

CladThickness, In.141.4.0243FuelRodO.D.,In.PelletDiameter, In.Diametral Gap,In.PelletDensity(Xtheoretical)

.400.3444.007095ControlRodGuideTubesOuterDiameter, In.Znrszcv4rP.t'<,lrl<0.52800.4900Instrument TubeOuterDiameter, In.gn&885gaPz.-.4zZu'.4015 0.34997044U012784 TABLE3'CARYOFLEOPARDRESULTS,FORHEASUREDCRlTiCALS Case~NumherReference XllmkccEnrichment (atom%)H20/UVoluneFuelPelletCladDensityDiameterDiameterCladThickness (cm)Lattice,Pitch(cm(CriticalBucklingm2Calculated

~kl2345678910ll1213141516(81920212223242526271212121313131414141415,161617l7171717179999101010102.73427342.7342.734.2.7342.7342.7342.7343.7453.7453.7454.0994.0994.0994.0694.0694,0693.0373.0370.7'I4*0.714>>0714>>0.714*0.729*0.729*0.729*0.729*2.182.933.807.028.4910.132.504.512.504.514.512.552.142.593.538.029.902.648.101.682.174.7010.761.113.493.491.5410.1810.1810.1810.1810.1810.1810.1&I0.1810.3710.3710.379.469.469.459.459.459.459.289.289.529.529.529.529.359.359.359.350.76200.76200.76200.76200.76200.76200.76200.76200.75440.75440.75441.12781.12781.12681.12681.12681.12681.12681~12680.85700.85700.85700,85701.28271.28271.2827l.28270.85940.85940.85940.85940.85940.85940.85940.85940.86000.86000.86001.20901.20901.27011.27011.27011.27011.27011.27010.99310.99310.993'I0.99311.44271.44271.44271.44270.040850.040850.040850.040850.040850.040850.040&50.040850.04060.04060.04060.04060.04060.071630.071630.071630.071630.071630.071630.05920.05920.05920.05920.08000.08000.0&000.0&001.02871.10491.19381.45541.56211.68911.06171.25221.06171.25221.25221.51131.4501.5551.6842.1982.3&11.5552.198l.32081.42241.86692.64161.75262.47852.47851.905040.7553.2363.2865.6460.0752.9247.568.8.68.395.195.6888.079.069.2585.5292.8491.7950.7568.81108.8121.5159.6128.489.1104.7279.590.01.00151.00521.00431.00981.0118lm00721.00080.99871.00101.00251.00090.98890.98300.99990.99581.00400.98720.994&0.98090.99121.00290.99441.00080.99021.00550.99480.9878*ThesearePu02inNaturalU02.>>>>Cases1through19arewithstainless steelclad,Cases20through27arezfrcaloy.'045U012784 0

TABLE4WESTINGHOUSE UOZr-4CLADCYLINDRICAL CORECRITICALEXPERIMENTS (6,7)2Exeriment12345678910ll121314NotesPitch1o0.6000.6900.8480.9760.6000.6000.6000.6000.6000.6000.6000.6000.8480.848BoronConcentration (m)0000306.536.4727.7104.218.330.446.657.1104.218.MaterialBuckling(forLEOPARD-CH-2.008793.009725.008637.006458.007177.006244.005572.008165.007599.007106.006661.005809.007320.006073CriticalNo.ofPins489.4317.0.251.6293.0659.9807.2950.2546.3607.1669.5735.3895.3321.0420.5RadiusofFuelRegion(cm)19.02117.60519.27623.93522.08824.42926.50420.09721.18622.24823.31525.72721.77224.919keff(LEOPARD/PD

-7)0.99120.99410.99270.99350.99270.99370.99400.'99190.99170.99160.99090.99440.99380.99250.9928Mean0.0012Std~t'11IlEnrichment FuelDensityPelletRadiusCladIRCladOR2.719w/oU-23510.41g/cm30.20in0.2027in0.23415in(b)Thickness ofwaterreflector isthatrequiredtoattaintotalradiusof50cmformodel.(c)B=.000527cm2Z "TABLE5BATTELLEFIXEDNEUTRONPOISONCRITICALS LengthTimesCaseMidth>>Ho.ofAssemblies InArrayAbsorberType,Thickness DistanceCriticalToFuelSeparation kffClusterofClustersLEOPARD/PO0 02020x1701722.21x16x00220x18.88+02820x16027'0x163Boral3Boral1BoralS.S.S.S..713cm.713.713.485cm.302.645cm.6452.732.645cm,6456.34cm5.226.88cm7.430.99320.99440.99250.99460.993503220x1703820x173S.S.1.1w/o8.298aa3S.S.1.6w/o8.298.645cm.6457.56cm7.360.99330.9931002801501302202120x18.07520x1720x1620x1520x16NoneHone.HoneHoneHone11.92cm8.396.394.460.99560.99420.99450.99330.9946Statistical Sugary:Seriesmember~meank.BoralS.S.S.S.(Borated)

~x~osoenTotalNon-Poison Total'UWera70.99340.99410.99320.99350.9944mm0.00080.00060.00010.00070.0007K3HJUE>>Thisisinunitsofpitch(Pitch>>2.032cm)xCenterassemblywas20xl6andtheoutertwowereelongated at22.21x16.

+20xl8.88wasoneassemblywithaboralsheetontwosides.Fuelregiondata:Enrichment

~2.35w/o,Pelletradius~0.5588cm,CladOR~.635cm,Mallthickness

>>.0762cm,Pitch>>2.032cm7045U012784

'ABLE6SAXTONPu02-U02CRITICALEXPERIMENTS (Reference 9)~Ext.BoronH0/UOTpPpm'ume)3371.682.172.174.7010.76.520.560.560.7351.040.99121.00291.0084.99441.0008-.0088+.0029+.0084-.0056+.000870440012784

'

TABLE7ESAOAPu02-U02CRITICALEXPERIMENTS (Reference 10)~Ext.BoronPu-240H0/U~ppmTEToume~k~108085268248'26~81.54.750.6901.11.6903.49.97583.49.97583.49'9758.99021.0055.9949.9948.9878.9945-.0098+.0055-.0051-.0052-.0122-.00557044U012784 TABLE8SUMMARYOFPREDICTIONS FORkffeff'INCRITICALITY EXPERIMENTS ExerimentSaxtonPu02-U02ESADAPu02-U02AllPu02U2Cases'.9995

+.00680.9946+.00610.9969+.00667044U012784 TABLE9SUMMARYOFREACTIYITY BIASESANDUNCERTAINTIES FORGINNAREGION2MDRDescrition~ftftRffBasicrackcellat20C,4.25H/oU-235030,000HWD/HT8.430inchpitch(seeFigure1)Usingone-quarter cellmodelCalculation BiasesLeopard/PDt) modelbiasModelingEffectMeshSpacingEffectMostReactiveTemperature

~overoperating rangeMostReactiveWaterDensityRegion1-Region2Interface EffectTotalBiasBasiccellincluding BiasesTolerances.

andUncertainties (95/95)Depletedfuelassemblyreactivityuncertainties Maximumerrorduetopitchtolerance MaximumerrorduetoSSthickness tolerance Maximumerrorduetopelletdensitytolerance

(+.015)Maximumerrorduetopelletdiametertolerance

(+.001")Calculational Uncertainty (2.82a)TotalUncertainty (statistical)

Maximumreactivity changefrombiasesanduncertainties Maximumk,including biasesanduncertainties

+0.0031+0.0005+0.0002+0.0000+0.0000+0.0123+0.01610.01310.00190.00020.00150.00050.01860.02290.03900.90720.92230.94627044U012784 TABLE10COMPUTEDINFINITEMULTIPLICATION FACTORSFORGINNAMDREnrichment w/o1.751.751.751.753.003.003.003.004.254.254.254.254.254.25ExposureMHD/MT010,00012,50015,00010,00020,00025,00030,000025,00030,00035,00040,00045,000Computedkm0.89730.79010.76490.74420.96090.86550.82150.77881.17010.94630.90720.86800.82880.79037044U012784 p~j+f]IIj)jk~%trrl~rprerrrr~]))/rrIrI~.tjjjj),laPrrr]~(JIjj\lgt))jjf~q'L0++JgZ~1I'-~)~

FIGURE2NETDESTRUCTION OFU-235VERSUSBURNUPINTHEYANKEEASYMPTOTIC NEUTRONSPECTRUM20II<<~~II<<<<4~~~~'IIII;I!!I~<<~iII,i~I~<<~~II~~k<<jilIi!!.<<~P')'I'tl':.r.tiIII..IliI:lI::..l'~'jr:~~~It.II~lj1<<lIII<<I~~<<~Ijl~[<<<<1I~~~i~~Il~gi,'pi)ai~~<<I'II'12810rfe8'7.rqI~i.'.3II'1it)liIjII~~.~I]1,II<<;~,~II<<iL"'i<<IK~e~InferredfromisotopicdataFreehandfitofdataPreviousLEOPARDunitcellcalc.~NPLGLEOPARDunitcellcalc.00121620IIIIrIIIIII (jjirj)/lCV x103)28 K

FIGURE3SPECIFICPRODUCTION OFU-236VERSUSBURNUPINTHEYANKEEASYMPTOTIC NEUTRONSPECTRUM4.0II3.5<<t<<'3.0<<(~(.1~~..s..(~0*I'Pt:'Jf\~+~~~I.(('+'Rtt~t4~<<i,g4<<i~(lI~~~Iio(,<<lP2.5gO2.0U40C41.5Rl.0~~i8(~J'(I.L~~.Ll.~~4.i+~~'(\L'L4.K~eInferredfromisotopicdataj,FreehandfitofdataPreviousLEOPARDunitcellcalc.,PLQLEOPARDunitcellcalc.0.5001216-20Sunup(WD/HIMx103)28 FIGURE4NETDESTRUCTION OFU-238VERSUSBURNUPXNTHEYANKEEASYMPTOTIC NEUTRONSPECTRUM128VpWsiaesK~e-~InferredfromisotopicdataFreehandfitofdata-Previous'LEOPARD unitcellcalc.~PLGLEOPARDunitcellcalc.

FIGURE5SPECZFZCPRODUCTION OFPU-239VERSUSBURNUPEgTHEYANKEEASYMPTOTIC NEUTRONSPECTRUM~g~pig.'L.R~~1~Iv-jItL-',+M:/jib~i0t~fI~)~~i~!I)I~!.I,~+Isir!-.-K~e~InferredfromisotopicdataFreehandfitofdataPreviousLEOPARDunitcellcalc.~PLGLEOPARDunitcellcalc.u'6aoBuzmup(le/AUx103)28

FIGURE6SPECIFICPRODUCTION OFPu-240VERSUSBURNUPZNTHEYANKEEASYMPTOTIC NEUTRONSPECTRUM2PO~~~~~IL~~II',ItX~PPI\1:FIJ.~I~~4II..'IsfsslI~Ii!.t).t~IIj!IsfL8<<gilsIi.~TPlI'si,:~~%sf!'s<<I~I>sI!isI);~~!II!ILt:ssH,'st;I-hJ'gIf~Is1.6~~!'j's:ssi~I'PTPI!!:iI.~~I,~~~I'i'~.'pIIfs1.4~~,~Iss;wl~-:~IIII'!i~Is'I~II"1sissI~~.I~~"'isiIIII~I~ss1.0'sg'J.gJ'"s~~(II~i!<fjf~"'scsPs0.8~r'rpp+0,6K~e~Inferredfron1isotopicdataFreehandfitofdataPreviousLEOPARDunitcellcalc.pLgLEOPARDunitcellcalc.00121620Bufffup(IBID/ICQ x103)24 FIGURE7SPECIFICPRODUCTION OFPu-241VERSUSBURNUPINTHEYANKEEASYMPTOTIC'EUTRON SPECTRUMLLK~eInferredfromisotopicdata-.FreehandfitofdataPreviousLEOPARDunitcellcalc.PLGLEOPARDunitcellcalc.1.21.0go8C0*oe6PcesO.4It41220Burnup(HMD/HEQx103)28 FIGURE8SPECIFICPRODUCTION OFPQ-242VERSUSBURNUPINTHEYANKEEASYMPTOTIC NEUTRONSPECTRUM0.28L24II~'i'K~eIInferredfromisotopicdataFreehandfitofdataPreviousLEOPARDunitcellcalc.',PLGLEOPARDunitcellcalc.limniili20)H.iIf(.i;~

IlIT(aiIlf:.l6CO0.12'o0'0.08C4C4IaPc00~JVI48l620BurnIIP(WD/KiiJxlO3)24

FIGURE9SPECIFICPRODUCTION OFTOTALPuANDFISSILEPuVERSUSBURNUPINTHEYANKEEASYMPTOTIC NEUTRONSPECTRUMNetProduction (Kg/MTU)1020~KeTotalPu(Pu-239+Pu-240+Pu-241+Pu-242)FissilePu(Pu-239+Pu-241)FreehandFitofDataPreviousLEOPARDunitcellcalc.PLGLEOPARDunitcellcalc.otaltu~~eWe'"J~Srt~etiotu~~a~~~410101\~1614101110araay(WD/kNa101)

ATOMPERCENTOFTOTALUI~+iI'Ii1~~~~~~I~~iI'II~I'I>'lf~~-rIg]ImaIf~I~II'l:I~I'l,'fir-I.I.I~H0WOa00td>IIl.~g~I1 FIGUREllPu-239/U-238 ATOMRATIOVERSUSEXPOSURE.QvI~li~)II'IIIjj:~:JI!Il~ilf!I:.!I.'.I',,!!il.I))J)!i!:jl:jjl.'Iiiji")'ii!i!'ill!I)JI"Jll.,!111'I'I!'.:It)iIII.'.;IfJjjilllil)jjItl:';;r:

.I)~SaxtonData-'I)~"):llI'J'I--I-'-

)Calculation

~Q6.Q5jj'.'l!I)Ill)I;I1tliItl:I!IIIIIIg:I'.IIi!i:i!i!:i:i'i!II~'1'I1I),".iiu},1)ll'la::Ii!I".'j.!Li'i,11'ill"-I:".!)i:i!:~F.11'~I.~~I~pgi'!~I'l).i.1)lllljiIi'i!)~i!'ii)jfIll!.'i.'ti!1'ii'!ill 1Itill11)l.I':~l.',jlf)'II'!'I:liiII)i!illi.l::iIi".I&I.~I~1'I681012141618,20MND/KgM PCCIATOMPERCENTOFTOTALPuCl~)~iLi~~C10tJ0I0t3OlP

190150vIv1Iv'I!"iflf.rIhltv~,IIIfII4Ir4)'I,Jvf4&4,agvl4rfI4ivllv4v'>>4!)IlvargI"II4IvIvtlv'+'lvIvrfvf'I'71Iv,aaJXvtfI~I'~IfvIf."II:ClaLiavllvvaI!l~)vl<</lhIIIIvvilvvv,IvailIAif1l41l.f<<llIyllvg>>-vgII!Iill,I"iIaIrahflvIaa,I$JvIvv'I1100av!!...,IFvtiv>>IIvvIIlvv.fIgvtIgIvaVlt44,~..'I~,julvfvfl',IIkaaaFLI4"vvlIvI500.001Figure13.0.1YearsafterShutdownFissionProductAbsorption Cross-Sections as1.10aFunctionofTimeAfterShutdown50 12GridElementsMATERIALIDENTIFICATION 1620241.PinCells2.GuideTubeCells3.Instrument TubeCells4.Stainless Steel5.Water6.BoraflexFigure14.One-(}uarter RackCellModelforGinnaMDR gg~ioI~~~g~

0.910~~p~~~Ik~)I4~0.906~~~I~0.908g;~$4y~<<t0~\tl~~f~~4~~<<~J~~~~'~~~SI~<I~'V'~~o~1ep0~~~~~~4~<<o~<<~~~~a4t~'t~<<et~0~~~~~<<I~<<aP<<~~~~Wt<<~t~fItt+to<<IQ0.9048.3008.4008500AssemblyPitch,inches8.600Figure16.Variation ofkwithAssemblyPitchforGinnaMDR(4.25w/o830,000MWD/MT,20'C) 0.9100.908i,,liHE>fw'rIp<<i.I~)~ipre~II~II~~(t~I~tsarKlLf.I.'if:

0.906pV'iL'l~I)II)~~yI$/)Ij4i)i~+~~~~~tt~'I~I~~)clif0.904)~gi~I1~i~~~<<~)li)iItjI)'.~<<!lj;6~Ir~~I~\~~~Ot~~I~iE!jg)IjnI0.1300.1100.120Normalized SteelThickness, inches(Boxthickness

+O.SxBoraflexretainerthickness)

Figure17.Variation ofkwithSteelThickness forGinnaNOR(4.25w/o930,000MAD/NT,20'C) 0.9100.908~~t,~~tW4~~~-'..I.j!i.i~I,~Ti[~~~qH7~4~~'jt0.906'~l4~4+14btt~~o~t~>>4sapw~~4l%~V~~I~~~Ii~fi+i.~~I~~0.9050.1715"0.1720"0.1725"01730"PelletDiameter, inchesFigure18.Variation ofkwithPelletDiameterforGinnaHDR(4.25wio830,000MWD/MT,20'C) 0.910~~~g+'~~~I~f5Li~IW~~1~f04/~~bOf4$jl4~~Ii+~CHILI~$~~0.908ot~;i,:II.".'k;

~It$sW~Lb~4f~p'Itt~~~~!~J~4~~~'~$~fiy~IIq.!lre~0.906~~~rg.,P..1I~~ilit~sy~f4~~~~'fg~aa.~\Qo~4~1+~yeo~i+08~fI0.9040.9300.9400.9500.9600.970PelletDensity,FractionofTheoretical Figure19.Variation ofkwithPelletDensityforGinnaMOR(4.25w/o9'30,000MWD/MT,20'C,Reference Dimensions) 1.0>>ouiccv.vaib'av<V<>OTseawaieruenslr.ytorViennaMOR(4.25w/o930,000MWD/MT,C,Reference Dimensions) 0.8l,l~~plr~I~~~~0.60.4Ilifii/,l~~~~i.'II~II~~fl1nII~~~~0.00.20.4pH20,g/cm30.60.8 0.910!~~~t~ft~t!0.908~>>~t~t~~t~~tt.!!t~t!ttt!~~~ft~~t0.906~fP~t>>'PEfgd!Pf)hatt~tt~tI>>>>I>>f!~~!~!~-'0~t+~~~~~~>>I>>~t~t~~~~t~t~~~I~~>>I>>4'T~~I~>>>t~ltl'~ut~pt~~~~~~.904608090100110Temperature,

'F70fQt+!at![Q%>>!4!pgfIHg)!jt!!!!ft(f.~L!l"!~~t~Figure21.Variation ofkwithTemperature forGinnaMDR"(4.25w/o830,000MWD/MT,Reference Dimensions)

I~~I.~~I~I~~~

B~I'.~~~~~'~~~~~~I~~~-~~

Attachment CInaccordance with10CFR50.91thesechangestotheTechnical Specifications havebeenevaluated againstthreecriteriatodetermine iftheoperation ofthefacilityinaccordance withtheproposedamendment would:l.involveasignificant increaseintheprobability orconsequences ofanaccidentpreviously evaluated; or2.createthepossibility ofanewordifferent kindofaccidentfromanyaccidentpreviously evaluated; or3.involveasignificant reduction inamarginofsafety.Theproposedmodification wouldincreasethespentfuelstoragecapacityatGinnafrom595fuelassemblies to1016.ThesafetyanalysishasshownthatthemodifiedrackssatisfyNRCStaffacceptedcriteriafornuclear,structural andthermalhydraulic design.Thediscussion belowexamineseachofthethreecriteriastatedaboveandsupportsthefindingthattheproposedmodification isoutsidethestandards of10CFR50.91.Therefore, ano'ignificant hazardsfindingiswarranted.

1.Theproposedmodification doesnotinvolveasignificant increaseintheprobability ortheconsequences ofanaccidentpreviously evaluated.

Fourpotential accidentscenarios havebeenidentified:

1)spentfuelcaskdrop;2)lossofspentfuelpoolforcedcoolingwater;3)seismicevent;4)spentfuelassemblydrop.Theprobability oftheseeventswillnotbeaffectedbytheamountoffuelstoredinthepool.

Theconsequences ofaspentfuelcaskdropaccidentareunchanged bythemodification.

ThecurrentTechnical Specifications prohibitthemovementofacaskintheauxiliary building.

AnApplication forAmendment totheOperating Licensehasbeensubmitted totheNRCtodeletethisrestriction bymodifying thecranetobesinglefailureproofinaccordance withtherequirements ofNUREG-0554.

Thiswouldobviatetheneedtoevaluatetheconsequences ofacaskdropaccident.

Thelossofspentfuelpoolforcedcoolingwaterhasbeenpreviously evaluated forboththecurrentpoolcoolingsystem,~'~

andthesystemtobeinstalled in1986.~'~Thedecayheat.loadsassumedintheseanalysesboundthosethatwillbeexperienced duetotheincreased storagecapacity.

Therefore theconsequences ofthisaccidentareunchanged fromthosepreviously evaluated.

Thestructural responseoffullyloadedstorageracksduringaseismiceventwasevaluated inSection4ofAttachment BtothisAppli;cation.

Theresultsofthisevaluation satisfied NRCStaffaccepteddesigncriteria.

Therefore.

theconsequences ofaseismiceventareunchanged.

Theconsequences ofasinglefuelassemblydrophasbeenevaluated inreference 2andinSections2and4ofAttachment, BtothisApplication.

Theevaluation indicates thatKeffremainsbelow.95.Sincetheproposedmodification onlyaffectsstorageofwellcooledfuel,themaximumradiological releaseswouldoccurfromthedropofanassemblyinRegion1whichisunchanged.

Therefore theconsequences ofafuelassemblydropareunchanged.

2.'Createthepossibility ofanewordifferent kindofaccidentfromany-accident previously evaluated.

RG&Ehasevaluated theproposedrackmodification inaccordance withtheNRCApril14,1978letter"NRCPositionforReviewandAcceptance ofSpentFuelStorageandHandlingApplication" andappropriate NRCandindustryguides,codesandstandards.

Initsevaluation, RGB'asfoundnoindication thatanewordifferent kindofaccidentiscreated.3.,Theproposedmodification doesnotinvolveasignificant reduction inthemarginofsafety.Undernormaloperation andaccidentconditions, theproposedmodifiedstoragerackdesignmust,satisfycertaincriteriainthreeareas:1.NuclearCriticality 2.ThermalHydraulic 3.Structural Mechanical Intheareaofnuclearcriticality, thecriteriaestablished isthatKeffmust,belessthan.95.Section2ofAttachment BofthisApplication indicates thatthiscriteriaissatisfied andtheresultsarenotsignificantly different thanpreviousanalyses.5 Thecriteriaitselfisunchanged fromprevioussubmittals, therefore themarginofsafetyhasnotbeenreduced.Section3ofAttachment BoftheApplication andpreviousanalysesvaluatethethermalhydraulic considerations ofthemodification.

Thisevaluation showsthatthedecayheatloadsofpreviousanalysesboundthosethatcouldresultfromthe1proposedmodification.

Therefore themarginofsafetyhasnotbeenreduced.3 Thestructural considerations dealprimarily withtheresponseoffullyloadedracksduringaseismicevent.Section4ofAttachment BtotheApplication presentsthestructural mechanical evaluation oftheracksandindicates that,theappropriate criteriaestablished byNRCguidanceandindustrypracticehasbeensatisfied.

Inaddition, theseanalysesestablish theacceptability ofpoolfloorloadsunderworstcaseconditions.

Withtheappropriate criteriasatisfied, thereisnosignificant reduction inthemarginofsafety.

r'4~