ML17309A916

Application for Amend to License NPF-16 by Incorporating Attached TS Rev.Amend Will Modify TS 5.6.1 & Associated Figure 5.6-1 & TS 5.6.3 to Accomodate Increase in Allowed SFP Storage Capacity

ML17309A916
Person / Time
Site:	Saint Lucie
Issue date:	12/31/1997
From:	STALL J A FLORIDA POWER & LIGHT CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML17229A570	List: ML17229A569 ML17229A571 ML17309A916 ML17309A917
References
L-97-325, NUDOCS 9801070046
Download: ML17309A916 (55)

Text

CATEGORY1REGULAYINFORMATION DISTRIBUTIOA "YSTEM(RXDS)lgACCESS1ON NBR:9801'070046 DOC.DATE:

97/12/31NOTARIZED:

YESDOCKET,5FACIL:50-389 St.;LuciePlant,Unit2,FloridaPower&,LightCo.05000389AUTH.NAMEAUTHORAFFILIATION

~~~S~~~~~~~~TALL,J.A.

FloridaPowerSLightCo.RECIP.NAME RECIPIENT AFFILIATION DocumentControlBranch(Document ControlDesk)

SUBJECT:

Application foramendtolicenseNPF-16byincorporating attachedTSrev.Amend willmodifyTS5.6.1&associated Figure5.6-18TS5.6.3toaccomodate increaseinallowedSFPstoragecapacity.

DISTRIBUTION CODE:AOOIDCOPIESRECEIVED:LTR IENCL(SIZE:I4(TITLE:ORSubmittal:

GeneralDistribution IgNOTES:ERECIPIENT IDCODE/NAME PD2-3LAWIENS,L.COPIESLTTRENCL1111RECIPIENT IDCODE/NAME PD2-3PDCOPIESLTTRENCL11INTERNAL:

ACRSNRR/DE/ECGB/A NRR/DRCH/HICB NRR/DSSA/SRXB OGC/HDS31111111110NRR/DE/EMCB NRR/DSSA/SPLB NUDOCS-ABSTRACT 11111111ERNAL:NOACNRCPDRDENOTETOALL"RIDS"RECIPIENTS:

PLEASEHELPUSTOREDUCEWASTE.TOHAVEYOURNAMEORORGANIZATION REMOVEDFROMDISTRIBUTION LISTSeORREDUCETHENUMBEROFCOPIESRECEIVEDBYYOUORYOURORGANIZATION, CONTACTTHEDOCUMENTCONTROLDESK(DCD)ONEXTENSION 415-2083TOTALNUMBEROFCOPXESREQUIRED:

LTTR14ENCL13 IIIgtt FloridaPower&LightCompany.6351S.OceanDrive,JensenBeach,FL34957December31,1997L-97-32510CFR50.90U.S.NuclearRegulatory Commission Attn:DocumentControlDeskWashington, D.C.20555Re:St.LucieUnit2DocketNo.50-389ProposedLicenseAmendment SELStoragaZap Pursuantto10CFR50.90,FloridaPower&.LightCompany(FPL)requeststoamendFacilityOperating LicenseNPF-16forSt.LucieUnit2by'incorporating theattachedTechnical Specifications (TS)revisions.

Theamendment willmodifySpecification 5.6.1andassociated Figure5.6-1,andSpecification 5.6.3toaccommodate anincreaseintheallowedSpentFuelPool(SFP)storagecapacity.

Theanalysessupporting thisrequest,inpart,assumecreditforupto1266ppmboronconcentration existingintheSFP.Asdiscussed withtheNRCStaff,itisrequested thattheproposedamendment, ifapproved, beissuedbyOctober31,1998.Attachment 1isanevaluation oftheproposedTSchanges.Attachment 2isthe"Determination ofNoSignificant HazardsConsideration."

Attachment 3containsacopyoftheaffectedTSpagesmarked-up toshowtheproposedchanges.Enclosure 1isthe"St.LucieUnit2Criticality SafetyAnalysisfortheSpentFuelStorageRackUsingSolubleBoronCredit",andEnclosure 2isthe"St.LucieUnit2SpentFuelPoolDilutionAnalysis."

Theproposedamendment hasbeenreviewedbytheSt.LucieFacilityReviewGroupandtheFloridaPower5LightCompanyNuclearReviewBoard.Inaccordance with10CFR50.91(b)(1),acopyoftheproposedamendment isbeingforwarded totheStateDesigneefortheStateofFlorida.Pleasecontactusifthereareanyquestions aboutthissubmittal.

Verytrulyyours,J.A.StallVicePresident St.LuciePlantJAS/RLDAttachments 980i07004b 97i23iPDRADQCK05000389,'

PDRggOlEnclosures (seenextpage)anFPLGroupcompanyIIIIIIIIIIIIIIIII IIIIIIII,IIIIIIIIIIII 0IP' St.LucieUnit2DocketNo.50-389ProposedLicenseAmendment L-97-325Page2

Enclosures:

(1)St.LucieUnit2Criticality SafetyAnalysisfortheSpentFuelStorageRackUsingSolubleBoronCredit,CENPD-387:

ABB-Combustion Engineering, October,1997.(2)St.LucieUnit2SpentFuelPoolDilutionAnalysis, PSL-ENG-SENS-97-068, Revision0:FPLNuclearEngineering,

November, 1997cc:RegionalAdministrator, RegionII,USNRC.SeniorResidentInspector, USNRC,St.LuciePlant.Mr.W.A.Passetti, FloridaDepartment ofHealthandRehabilitative Services.

St.LucieUnit2DocketNo.50-389ProposedLicenseAmendment SHoMtorag~apacity~tuble Boraa&redit L-97-325Page3STATEOFFLORIDA))ss.COUNTYOFST.LUCIE)J~A.Stallbeingfirstdulysworn,deposesandsays:ThatheisVicePresident, St.LuciePlant,fortheNuclearDivisionofFloridaPower5LightCompany,theLicenseeherein;Thathehasexecutedtheforegoing document; thatthestatements madeinthisdocumentaretrueandcorrecttothebestofhisknowledge, information andbelief,andthatheisauthorized toexecutethedocumentonbehalfofsaidLicensee.

J.A.StallSTATEOFFLORIDACOUNTYOf&LLI.C.(CSworntoandsubscribed beforemethis3~dayofttdfqbyJ.A.Stall,whoispersonally knowntome.~MnrMSignature,o;fI)oo aryPyric>-Qggiof Florida:s;MYCOMMISSION 0CC646163EXPlAESMay12,2001BOIIOEOTHIIVTIefFAINNSURANCE, INO.NameofNotaryPublic(Print,Type,orStamp) 08"I,,t0

~~St.LucieUnit2DocketNo.50-389ProposedLicenseAmendment EVALUATION OFPROPOSEDTSCHANGESforST.LUCIEUNIT2SPENTFUELPOOLCAPACITYINCREASEAdaptedfromFPLNuclearEngineering SafetyEvaluation PSL-ENG-SENS-97-083, Revision0,12/17/97, 9801070046 50-389 St.LucieUnit2DocketNo.50-389ProposedLicenseAmendment L-97-325Attachment 1Page1of2

2.0 DESCRIPTION

OFCHANGES3.0THERMAL-HYDRAULIC CONSIDERATIONS 3.1DecayHeatCalculations fortheSpentFuelPool3.1~13.1.23.1.33.1.43.1.5PurposeandScopeofCalculation Acceptance CriteriaDescription oftheFuelPoolCoolingSystemCalculations Performed Results3.2MaximumFuelCladdingTemperature 3.2.1Purpose3.2.2Discussion andResults4.0REACTIVITY CONSIDERATIONS 104.1Methodology UsedinReactivity Calculations 4.2Acceptance Criteria4.3RegionI-Description ofStorageArrangement Analyzed4.4RegionII-Description ofStorageArrangement Analyzed4.5Calculational Assumptions andResults4.6Reactivity Equivalencing 4.6.1BurnupandDecayTimeReactivity Credit4.6.2Gadolinium Reactivity Credit4.7Postulated Accidents 4.8Criticality Analysis-Conclusions

5.0 SEISMICANDSTRUCTURAL

CONSIDERATIONS St.LucieUnit2~~DocketNo.50-389ProposedLicenseAmendment BKSBWML-97-325Attachment 1Page2of296.0ASSESSMENT OFPOTENTIAL FORINADVERTENT FUELPOOLDILUTION206.16.26.36.4Description ofMethodology BoronDilutionInitiating EventsResultsofInitiating EventsSpentFuelPoolDilutionEventConclusions

7.0 NOSIGNIFICANT

ENVIRONMENTAL IMPACT237.1ThermalImpact7.2Radiological Evaluation 7.2.1SolidRadwaste7.2.2GaseousRadwaste7.2.3Radioactive ReleasesduetoAccidents

8.0CONCLUSION

S

9.0REFERENCES

2627LlSIOEXLBLESSummaryofSt.LucieUnit2Calculated FuelStorageRackStressIntensities 28St.LucieUnit2Estimated SpentFuelPoolCapacityRequirements 29 St.LucieUnit2DocketNo.50-389ProposedLicenseAmendment SEP~ragaZapacit L-97-325Attachment 1Page3of29EVALUATION OFPROPOSEDTSCHANGES1.0TheexistingspentfuelstorageracksatSt,LucieUnit2containatotalof1584cells,ofwhich1076arecurrently available forstorage.Theestimated storagecapacityrequirements areillustrated inTable2.AsofNovember1997,theSt.LucieUnit2fuelpoolcontains692permanently discharged fuelassemblies.

Bytheyear2001,St.LucieUnit2willhavefilledallfuelpoolstoragelocations notreservedforafullcoreoff-loadoffuel;by2006,Unit2willhavelosttheabilitytodischarge anyfuelfromthereactor.Toensurethatsufficient capacitytostoredischarged fuelassemblies continues toexistatSt.LucieUnit2,analyseshavebeenperformed whichsupportanincreaseinthenumberoffuelassemblies whichmaybe,storedinthefuelpoolfromthecurrentlimitof1076toanewvalueof1360.Theproposedcapacityincreasewillextendthefull-core-reserve storagecapability oftheUnit2fuelpoolfromyear2001toapproximately 2007.Finaldisposalfacilities forspentfuelwillnotbeavailable untilatleast2010.Theavailability ofanycentralized interimfacilityforspentfuelstorageisuncertain.

AlthoughdrystorageofspentfuelmayberequiredattheSt.Luciesiteinthefutureevenwiththeapprovaloftheproposedlicenseamendment, itisprudenttomaximizethestoragecapability oftheexistingfuelpoolpriortoinitiating'he licensing andconstruction ofanon-sitedrystoragefacility.

Deferring therequirement fordrystorageatSt.Luciewillpermittheuseofmulti-purpose canisters (MPCs)whicharecurrently beingdeveloped andlicensed.

UseofMPCsforon-sitefuelstorageandoff-sitefueltransport willbenefitradiation workersbyreducingthetotaloccupational exposureandwillminimizethegeneration oflowlevelradioactive wasteduetodrystorageofspentfuel.2.0FPLproposestomodifySection5.6oftheUnit2Technical Specifications, asshowninAttachment 3,topermitanincreaseinthestoragecapacityoftheexistingspentfuelpoolstorageracksfrom1076to1360assemblies.

Technical Specification Figure5.6-1willberemovedandnewFigures5.6-1athrough5.6-1ewillbeaddedtodescribetheassemblyburnuprequirements forRegionIandIIofthespentfuelpool.Theexistingrequirement forafuelpoolsolubleboronconcentration of>1720ppmisretained.

St.LucieUnit2DocketNo.50-389ProposedLicenseAmendment L-97-325Attachment 1Page4of29Aspartoftheproposedchange,thepermissible storageconfiguration ofRegionIwillbemodified; anumberofcellblockingdeviceswillberemovedandthenumberofusableRegionIcellswillincreasefrom224to276.FPLexpectsthatcellblockremovalandsubsequent fuelrepositioning operations canbeperformed following NRCissuanceoftheproposedlicenseamendment withoutpriorNRCapprovalpursuantto10CFR50.59.RegionIwillretaintheability,foradditional fuelcycles,toacceptafullcoredischarge ofirradiated fuel.Additional permanently discharged fuelwhichdoesnotqualifyforstorageinRegionIImayalsobestoredinRegionI.Theproposedamendment wouldincreasethenumberofusableRegionIIstoragecellsfrom852to1084.Justification fortheseproposedchangesisprovidedinSections3through7ofthisevaluation.

Approvalofthisproposedlicenseamendment bytheNRCmayrequireFPLtorequestamodification toitscurrentexemption fromtherequirements of10CFR70.24.Criterion 4oftheexemption from10CFR70.24requiresak,<<of0.95forunborated waterinthespentfuelpool.NRCrulemaking activityisunderwaywhichwillobviatetheneedforanexemption modification request.3.0Thethermal-hydraulic analysisisformallydocumented inthe"St.Lucie2SpentFuelPoolThermalHydraulic Analysis,"

ABBCombustion Engineering NuclearOperations Calculation Number:016-AS95-C-009, Rev.0,6/09/95,andisavailable fromFPLNuclearEngineering records.3.1DECAYHEATCALCULATIONS FORTHESPENTFUELPOOL3.1.1BecauseFPLisproposing toincreasethequantityofspentfuelthatmaybestoredinthefuelpoolwithoutmakinganymodifications tothefuelpoolorthefuelpoolcoolingsystem,itisnecessary toensurethattheexistingequipment hassufficient heatremovalcapacitytohandletheincreased load.Inthecourseofperforming therequiredcalculations, FPLincludedtheeffectsofapotential i~creaseinthenumberofassemblies permanently discharged ateachrefueling outageintheevent24monthlongoperating cyclesareimplemented.

Theselongercyclesmayresultinincreased batchaveragedischarge burnups St.LucieUnit2DocketNo.50-389ProposedLicenseAmendment L-97-325Attachment 1Page5of29whichwerealsoaccounted forintherevisedcalculations.

TheABB-CEPCcomputercodeSFPOOL(Reference 6)wasusedtoperformmostcalculations discussed inSection3ofthisevaluation.

Toensurethatthemethodology chosenforcalculation ofthedecayheatloadproducedconservative results,aseriesofbenchmark calculations wereperformed basedontheconditions existinginthespentfuelpoolasofOctober1,1994.Onthatdate,544discharged assemblies werestoredinthespentfuelpool.Theinitialenrichments, operating histories anddischarge burnupsoftheseassemblies arewellknown.3.1.2recceTheperformance ofthefuelpoolcoolingsystemandthefuelpooltemperature valuesderivedfromthisreanalysis werecomparedtothecriteriagiveninupdatedFSARsection9.1.3.3:Foranormalrefueling evolution, themaximumfuelpooltemperature remainsatorbelow150'F;wheremaximumtemperature valuesfromthereanalysis exceededthe150'FvaluegivenintheFSAR,anadditional reviewoftheanalysisofrecordforthefuelstoragerackstructure wasundertaken toensurethatacceptable stresslevelsforrackcomponents werenotexceeded.

Themaximumfuelpooltemperature following thelimitingpostulated fullcoreoffloadevolution wasdetermined toremainlessthanboiling.Normalrefueling evolutions atSt.LucieUnit2currently employfullcorefueloffloads.Compliance withpooltemperature limitsisensuredthroughtherequiredinitialconditions specified inaseparate10CFR50.59safetyevaluation (Reference 12);typicalconstraints includelimitsonthefuelcoolingtimepriortooffloadinitiation, therateofdefueling tothefuelpool,andthemaximumtemperature oftheultimateheatsink.Following approvalofthisPLAbytheNRC,Reference 12willberevisedandusedtolimitspentfuelpooltemperature following anyplannedfullcoreoffloadto~150'F.3.1.3TheFuelPoolCoolingSystemprovidescontinuous coolingforspentfuelassemblies storedinthefuelpool~Thispermitsstorageofspentfuelassemblies inthepoolfromthetimethefuelisunloadedfromthereactorvesseluntilitisloadedintocasksforshipmentoffsiteoron-sitedrystorage.

St.LucieUnit2DocketNo.50-389ProposedLicenseAmendment L-97-325Attachment 1Page6of29TheSt.LucieUnit2fuelpoolcoolingsystemincludestwofuelpoolheatexchangers cooledbyshellsidecomponent coolingwaterandtwofuelpoolpumpspoweredfromseparatemotorcontrolcentersproviding forcedcirculation.

Eachfuelpoolpumphasadesignflowrateof1500gpm.Considering thevolumedisplaced byafullloadingofspentfuel,thenetfuelpoolliquidvolumeisapproximately 300,000gallonsincludin'g thefuelcaskarea.Thecaskloadingareaisthermally andhydraulically coupledtotheremainder ofthefuelpool~Suctionforthefuelpoolheatexchanger isdrawnfromnearthetopofthepoolandisreturnedafterbeingcooledthroughpipingwhichdischarges nearthebottomofthepool.Normally, onefuelpoolheatexchanger andonefuelpoolpumpareinservice;twopumpsmaybealignedtooneheatexchanger ifdesired.Todate,noheatexchanger tubeshavebeenpluggedasaresultofthecoolingsystem'soperation.

Redundant fuelpooltemperature andlevelsensorsprovidelocalreadingsandalarmindications intheUnit2controlroom.Fuelpoolpumpsandheatexchangers arelocatedintheFuelHandlingBuildingbutarenotlocatedinthevicinityofthefuelpool.Additional detailsonthefuelpoolcoolingsystemmaybefoundinupdatedFSARsection9.1.3.3.14Inevaluating thecapability ofthefuelpoolcoolingsystemtohandletheincreased coolingload,fourseparatecalculations wereperformed.

Thesewereselectedtodemonstrate thatmodelingofthepoolcoolingsystemandstoredassemblies producedconservative resultsunderavarietyofconditions.

Sensitivity studieswereperformed fortwoofthesecalculations (cases1&2)toquantifysourcesofconservatism inthemethodology'.

Case1involvedabenchmark ofthecomputercodecalculated resultstofuelpoolcoolingsystemdatacollected inOctober,1994.Actualdischarged assemblyburnupandenrichment information wasusedinthiscomparison.

Sensitivity studieswereperformed toevaluatetheeffectsofthe2ouncertainty onpower,evaporative coolinglossfromthewatersurface,abestestimateheattransfercoefficient acrosstheheatexchangers, andacombination ofthesethreefactors.InCase2,acomparison wasperformed betweentheresultsoftheexistinganalysisofrecordforSt.LucieUnit2(whichusestheNRCAuxiliary SystemsBranchTechnical Position9-2)andtheequivalent scenariousingthemethod St.LucieUnit2DocketNo.50-389ProposedLicenseAmendment L-97-325Attachment 1Page7of29documented inANSI/ANS-5.1-1979.

Asensitivity studywasperformed usingtheANSI/ANSmethodology toquantifytheeffectonfuelpooltemperature ofassumptions concerning burnupofthefueloffloadedfromthecore.Case3calculated thefuelpooltemperature resulting fromtheplacement ofafullcoreofoffloadedfuelintothespentfuelpool7daysafterreactorshutdownwiththefuelpoolalreadycontaining 1300previously discharged

.assemblies.

Thiscaseusedlimitingvaluesforbatchaverageandfullcoredischarge exposures.

Case4determined thefuelpooltemperature resulting fromthedischarge ofarefueling batchof96assemblies 5daysafterreactorshutdownconcurrent withanactivefailureinthefuelpoolcoolingsystem.Thetotalfuelpoolloadingforthiscasewas1492assemblies, thusprecluding afullcoreoffload.Foreachcase,thefuelpoolwaterboiloffratewasalsodetermined assumingatotallossof.fuelpoolcooling,Thisratewasusedtoquantifythetimeavailable forsystemrepairsorotherremedialactionpriortoadecreaseinfuelpoolwaterleveltoapoint9feetabovethetopofthefuelseatedinthestorageracks.Subsequent tothesecalculations, Reference 10evaluated theimpactoftheuseoftheABB-CE"value-added" fueldesignonthisanalysis.

3.1.5BesultsCase1demonstrated thatthemodelingschemechosentorepresent thefuelpoolproducedatemperature approximately 7'Fhigherthanthatgivenbyactualplantdata.Calculations providedanexpectedfuelpooltemperature of92.8'F;plantdataprovidedafuelpooltemperature of86.0F.Whenbestestimateevaporative losses,heattransfercoefficients, andtheremovalofthe2o'ecayheatuncertainty wereconsidered, thepredicted fuelpooltemperature decreased to91.1'F,thusdemonstrating theconservative natureofthemodelingofthefuelpoolanddischarged fuel.ANSI/ANS-5.1-1979 decayheatmethodology wasusedthroughout thiscalculation.

Case2demonstrated thatthesimplified ANSI/ANS-5.1-1979 decayheatmethodology producesahighercalculated fuelpooltemperature valuethandoesNRCBranchTechnical Position9-2.Thiscaseanalyzedasituation wheretheUnit2fuelpoolcontains1113discharged fuelassemblies, including afull St.LucieUnit2DocketNo.50-389ProposedLicenseAmendment L-97-325Attachment 1Page8of29coredischarge whichhascooledfor7days.Resultsgivetemperature valuesof154.2'Fwithtwofuelpoolpumpsoperating usingtheANSI/ANSmethodology ascomparedtoapreviously reportedvalueof(150'F.Case3demonstrated thatforafuelpoolcontaining 1517assemblies, including 217fuelbundlesoffloadedfromthecore7daysfollowing reactorshutdown, themaximumfuelpoolwatertemperature was170.9'Fwithonefuelpumpinoperation and154.9'Fwithbothspentfuelpumpsinoperation.

Theresultant heatloadforthiscasewas35.22E6Btu/hrincluding uncertainties.

Actualdischarge exposures wereusedforfuelplacedinthespentfuelpoolpriortoJune1995;fueldischarges subsequent tothistimeweremodeledusingconservative cumulative exposurevaluesincluding avalueof55,000MWD/MTUforeachofthe217assemblies offloadedfromthecore.PursuanttotheguidanceinNUREG0800,thiscalculation hasdemonstrated thatnospentfuelpoolbulkboilingoccursandthus,thecriteriaofNUREG0800,Section9.1.3issatisfied:

Theanalysesdiscussed inSections3.1.4and3.1.5ofthisevaluation containanumberofconservatisms whencomparedtotheactualplantconditions thatwillexistfollowing approvaloftheproposedlicenseamendment (seeaboveparagraphs).

Theseconservatisms tendtoincreasethecalculated maximumfuelpooltemperature.

Themaximumspentfuelpoolwatertemperature following anyplannedfullcorefueloffloadatSt.LucieUnit2willbemaintained s150'Fbytheplantrestrictions specified inReference 12.This150'Fvalueisconsistent withthefuelpooltemperature limitgiveninNUREG0843(St.LucieUnit2SER)following afullcoreoffloadwithtwocoolingpumpsinoperation.

Foratotallossoffuelpoolcooling,Case3providesthelimitingfuelpoolboil-offrate.Forthiscasetheboil-offratewasdetermined tobe73.3gallons/minute.

Atthisrateofboil-off, 37.9hoursarerequiredforthepoolwaterleveltodropto9feetabovethetopoffuelseatedinthestorageracks.Case4demonstrates thatforaseriesofpartialcoreoffloadsandusingboundingparameters forassemblyburnup,fissionproductgeneration, andfuelpoolcoolingsystemheattransfer, theresulting fuelpoolwatertemperature remainslessthan150'F.Themaximumheatloadcalculated forthiscase,including theeffectofdecayheatuncertainties, was19.76E6Btu/hr.Withallowance foractivecomponent failures(bothapumpandheatexchanger assumedunavailable) thefuelpoolwatertemperature wascalculated tobe pfII St.LucieUnit2DocketNo.50-389ProposedLicenseAmendment L-97-325Attachment 1Page9of29139.8'F.Considering onlythesecondheatexchanger tobeunavailable (2pumpsfeedingasingleheatexchanger) theresulting poolwatertemperature is130.8'F.Bothofthesevaluesarewithinthe150'Fcriterion specified inSection9.1.3.3oftheupdated.St.

LucieUnit2FSAR.Reference 10hasdetermined thatuseofthevalue-added fueldesignatSt.LucieUnit2willhavenoadverseeffectontheconclusions of'thefuelpoolcoolinganalysis.

3.2IVIAXIIVIUM FUELCLADDINGTEMPERATURE 3.2.1Purpose.Itisimportant toensurethatfuelrodcladdingintegrity willbemaintained underlimitingconditions inthespentfuelpoolenvironmerit.

Todothis,calculations wereperformed, usingconservative inputs,todemonstrate thatfilmboilingdoesnotoccuratthesurfaceofthecladintheeventofa.lossofforcedflowcooling;i.e.theheattransfercoefficient remainswithintherangeofnucleateboiling.3.22Themaximumlocalheatfluxatthefuelrodsurfaceforanassemblydischarged tothefuelpool3daysafterreactorshutdownhasbeencalculated tobe1980.9Btu/hr-ft'.

Thephysicsandgeometryparameters usedasinputtothiscalculation (peakingfactors,rodburnupandroddiameter) wereselectedtomaximizetheheatfluxvalueandtoboundbothcurrentandvalue-added fueldesigns.Thecalculation ofpeakcladdingtemperature inafuelpoolenvironment couplesthemaximumcalculated surfaceheatfluxwithanempirical equationforfreeconvection thatassumesaconstantcladdingsurfacetemperature.

Inthisempirical equationfluidproperties areevaluated atthesaturation temperature.

Toensureaconservative resultwhenapplyingthisequation, theaxialpositionofthemaximumdecayheatfluxisassumedtobelocatedatthebottomofthespentfuelassembly.

Thesaturation temperature atapooldepthcorresponding tothebottomofthefuelassemblyseatedinthestorageracksis252'F.Forthiscondition, theempirical correlation usedintheSFPOOLcomputercodeproducedapeakfuelcladdingtemperature of309.2'F.

f1 St.LucieUnit2DocketNo.50-389ProposedLicenseAmendment L-97-325Attachment 1'age10of29Asacheckontheabovecalculated temperature value,theRohsenowboilingcorrelation (Reference 7)wasalsousedtocalculate thepeakcladdingtemperature.

Thecladdingtemperature calculated usingthismethodisconsistent withthe309.2'Fvaluereportedabove.Thetemperature valuescalculated usingthemethodsandconservative inputdescribed aboveprovideassurance thatfuelrodcladdingwillbemaintained intactin'theeventofalossoffuelpoolcooling.4.0Thefollowing subsections describetheproposednewconfiguration oftheSt.LucieUnit2spentfuelpool,themethodology usedtogeneratecalculated valuesofreactivity andeffective neutronmultiplication tosupportthisconfiguration, andtheanalysisresults.44.1METHODOLOGY USEDINREACTIVITY CALCULATIONS Criticality calculations tosupporttheproposedincreaseintheSt.LucieUnit2spentfuelpoolstoragecapacityhavebeenperformed byABB-CEusingmethodology consistent withthatdescribed inWCAP-14416 (Reference 3).ThisWestinghouse OwnersGroupreportwassubmitted totheNRCinJuly,1995andwassupplemented inOctober,1996.Theanalysismethodology usedbyABB-CEintheevaluation ofthespentfuelstoragerackconfiguration employs:(1)SCALE-PC, apersonalcomputerversionoftheSCALE-4.3 codepackage(whichincludesKENO-Va,NITAWL,CSAS-2andBON-AMI),

withtheupdated44groupENDF/B-5crosssectionlibrary,and;(2)thetwo-dimensional integraltransport codeDITwithanENDF/B-6neutroncrosssectionlibrary.Adetaileddiscussion oftheapplication ofthiscriticality methodology maybefoundinEnclosure 1tothisevaluation.

BothregionsoftheUnit2spentfuelpoolwillcreditthepresenceofsolubleboron;mostanalysesoftheUnit2poolmodeledbothRegionIandRegionIIexplicitly inasinglecalculation.

4.2ACCEPTANCE CRITERIATheSERissuedbytheNRC(Reference 2)forsolubleboroncreditmethodology requirestheapplication ofatwopartacceptance criteriatotheSt.LucieUnit ttt St.LucieUnit2DocketNo.50-389ProposedLicenseAmendment L-97,-325 Attachment 1Page11of292spentfuelstorageracks.First,the95%probability 95%confidence (95/95)valueoftheeffective neutronmultiplication factor(k,<<)fortheproposedspentfuelstoragearraymustbelessthan1.0whenanalyzedwith0ppmsolubleboron,including theeffectofalluncertainties andtolerances.

Secondly, theacceptance criteriaforfuelpoolconditions withsolubleboronpresentrequirethatthe95/95k,<<mustbelessthanorequalto0.95,including theeffectofall.uncertainties andtolerances..

Reactivit'y calculations forthespentfuelracksalsoincludetheeffectoftwobiases.Computercodebiasesbasedonthederivedvalueofk,fromKENO-Vacomparedagainstexperimental benchmarks areapplied.Inaddition, thereactivity effectsofpossiblefuelpooltemperature variations encountered duringnormaloperation areincluded.

Enclosure 1(anditsreferences) alsoprovidesasummaryofthecomparisons madetoexperimental datathatwereusedtoderivetheKENO-Vareactivity biasanduncertainty.

Bothcalculations performed at0ppmsolubleboronandcalculations whichcredittheeffectofsolubleborononstoragerackreactivity alsoincludetheeffectsoftolerances infuelassemblyenrichment, fabrication andpositioning parameters, fuelrackconstruction tolerances, anduncertainties inthecalculation ofstoragerackreactivity, controlelementassembly(CEA)worthandassemblyburnup.Inadditiontotheboronconcentration requiredtocompensate foruncertainties andtolerances incalculations ofk.<<fornormalstorageconditions, theamountofsolubleboronrequiredtocompensate forpostulated accidentconditions isalsoquantified.

4.3REGIONI-DESCRIPTION OFSTORAGEARRANGEMENT ANALYZEDThestoragearrangement forRegionIproposedbythislicenseamendment preserves thecapability tofullyoffloadfuelfromtheUnit2reactorvesselbyproviding storagespacefor276fuelassemblies.

TheproposedRegionIstoragegeometryisshowninFigure9ofEnclosure 1;adiscussion ofthespecificstoragerequirements forthisregionissummarized below.RegionIcontinues tomakeuseoffluxtrapstoincreaseneutronleakage(andminimizek,<<)throughplacement offuelnexttoregionsofwater.Twonoteworthy differences betweentheproposedarrangement andtheexistingRegionI

~~~St.LucieUnit2DocketNo.50-389ProposedLicense'Amendment L-97-325Attachment 1Page12of29storagearrangement are:(1)thattheannularwaterregionbetweentheexterioroftherackarrayandthefuelpoolwallservesasanexplicitly-analyzed neutronsink,and(2)thatarowofvacant,water-filled storagecellscanservetoneutronically decoupleregionsoffreshfuelplacedoneitherside.AsshowninFigure9ofEnclosure 1,theU-shapedrows(orrings,beginning attheoutsideofthearrayandworkinginward)1,3and9ofRegionIwillhold120fuelbundles(andupto56fullstrengthCEAs)inahigh(89%)densityarray.Themostreactive(orlowestburnup)fuelassemblies fromthecoreoffloadwillbeplacedinthesethreerings,.TheU-shapedrows5,6,8and11areusedtostoretheassemblies fromthecoreoffloadwiththegreatestburnup(orlowestreactivity).

Depending ontheirburnup,certainoftheseassemblies mayberequiredtocontainfullstrengthCEAs.Theadditional storagelocations inrows8,11,andthe3by10arrayatthelowercenterofFigure9maybeusedtostorepermanently discharged fuelwhichdoesnotmeetthecriteriaforstorageinRegionII.TheU-shapedrows2,4,7and10serve.asfluxtrapsandwillremainvacant.Intherackcriticality

analysis, mostfuelplacedinrows1,3and9isassumedtohaveaninitialenrichment'of 4.5w/oU"';twoassemblies eachinrows1and3andoneassemblyinrow9areassumedtohavea1.82w/oU"'reshfuelequivalent.

Theanalysisoffuelstoredinrows5,6,8,11andthe30assemblycenterarrayalsoutilizesaconservative creditforthereactivity depletion oftheoffloadedfuelplacedhere.Inallcoreoffloadscenarios applicable toSt.LucieUnit2,someportionofthefuelwillhaveaccruedappreciable burnupandneednotbeanalyzedasfreshfuel.4,4REGIONII-DESCRIPTION OFSTORAGEARRANGEMENT ANALYZEDTheproposedfuelstoragearrangement forRegionIIofthespentfuelpoolincreases thestoragedensityoftheregionto95.4%fromthecurrentvalueof75%.AllofRegionIIcontinues torequireaminimumvalueofassemblyburnupforstorage.Thisrequiredburnupvalueisafunctionoftheinitialfuelassemblyenrichment anditsdecay(orcooling)time.Therelationship betweenfuelcoolingtimeandrequiredburnupisprimarily duetothe14.3yearhalflifeofPu"'.Overtime,thisfissileisotopedecaystoAm"',whichisprimarily aneutron.absorber.

DecayofPu'4'ddsasignificant amountofnegativereactivity tothefuelpool.

St.LucieUnit2DocketNo.50-389ProposedLicenseAmendment L-97-325Attachment 1Page13of29Theconservative initialneutronsourcedistribution assumedforsubcritical multiplication ensuresthatRegionIIcontrolsthereactivity oftheentirefuelpool.Toensuresufficient reactivity margintothe1.0k,<<limit,eachRegionIIrackmoduleretains4vacantinteriorcells,detailedinFigure10ofEnclosure 1,whichserveasfluxtraps.TheproposedRegionIIstoragearrangement alsorecognizes that,becauseofdifferences inneutronleakage,theburnuprequirements forfuelstorageintheinteriorofRegionIIaremorerestrictive thanthoseforfuelstorageintheouterrowofRegionIIwhereanassemblyfacesavacantRegionIcell,orfacesthewatergapseparating thestorageracksfromthefuelpoolwall.SpentfuelrackstoragecellslocatedintheinteriorofRegionIIrequireanassemblyburnupequivalent to1.3w/oU"'reshfuel,priortoanycreditforactinidedecay,topermitfuelstorage.Storagecellslocatedontheperiphery ofRegionIIwithatleastonesurfacefacingwaterrequireanassemblyburnupequivalent to1.5w/oU"'reshfuel,priortocrediting actinidedecay.4.5CALCULATIONAL ASSUMPTIONS ANDRESULTSTheassumptions listedbelowwereusedforSt.LucieUnit2incalculations ofthek,<<applicable tothespentfuelpoolstorageracks:Fuelassemblies containuraniumdioxideatthenominalenrichment overtheentirelengthofeachrod.Thereactivity effectofaa0.05w/ovariation inUO,enrichment hasbeenincludedinthereactivity

'olerances anduncertainties.

2.Fuelrodshavebeenmodeledconsidering thedesigncharacteristics of.theABB-CE"value-added".

pellet,whichisplannedforinsertion intoUnit2forcycle11.Modelingthisdesignconservatively boundsthecurrentfueldesignrelativetoreactivity equivalencing.

Thereactivity effectsofa2%uncertainty inthefuelrodstackdensityhavebeenconsidered; thisuncertainty valueisconservative comparedtotheobservedhistoryofvariations inthisparameter.

3.Allfuelassemblies areassumedtocontain236fuelrodsina16x16fuelrodlattice.Table3ofEnclosure 1tabulates thefuelparameters utilizedinthefuelpoolcriticality analysis.

St.LucieUnit2DocketNo.50-389ProposedLicenseAmendment L-97-325Attachment 1Page14of294.Tolerances duetouncertainties inthethickness ofL-inserts (RegionI)andrackstoragemodulewallshavebeenconsidered.

5.Tolerances duetouncertainties inpositioning offuelassemblies withinthestoragecellshavebeenconsidered.

Fornominalcalculations, fuelassemblies wereassumedtobecenteredwithineachstoragecelltype.UsinginfinitearraysofbothRegionIandRegionIItypecells,thereactivity effectsofoff-center assemblyplacement wereexamined.

6.Thereactivity effectsofvariations instoragecellinteriordimensions (ID)andcellpitchhavebeenconsidered.

7.Themoderator iswatercontaining either0ppm(forcomparison to1.0k,limit)or350ppmsolubleboron(forcomparison to0.95k,<<limit)atatemperature of50'F.8,A95/95confidence levelassessment ofcalculated CEAworthwasdeveloped forapplication totheRegionIstoragerackarray.ThisvaluewasbasedonCEAworthcomparisons betweenpredictions andmeasurements fromoperating reactorsandcomparisons betweenDITandKENO-Vacalculations ofrodworth.Usingtheseassumptions, theKENO-VamodeloftheSt.LucieUnit2storagerackscalculated ak,of0.97001forthe0ppmsolubleboroncondition, priortotheapplication ofanybiases,tolerances oruncertainties.

Including theeffectofthesefactors,theresulting k,<<valueis0.99801.Thisvalueislessthanthe'k~acceptance criteriavalueof1.0for0ppmconditions.

Page30ofEnclosure 1providesadetailedtabulation ofthereactivity effectforeachbiasoruncertainty.

Table5ofEnclosure 1providesadetailedaccounting ofthereactivity effectofeachbiasoruncertainty forthecalculation ofthestoragerackk,<<inthepresenceofsolubleboron.At350ppm,priortoapplication ofanybiasesoruncertainties, k,<<wasdetermined tobe0.91497.Afterapplication ofallbiases,tolerances anduncertainties, k,<<equals 0.94797.Thisvalueislessthanthe0.95acceptance criteriaforfuelpoolk,<<inthepresenceofsolubleboron.

St.LucieUnit2DocketNo.50-389ProposedLicenseAmendment L-97-325Attachment 1Page15of294.6REACTIVITY EQUIVALENCING Reactivity equivalencing isusedtodefinetheconditions underwhichfresh,burnedandshimmedfuelassemblies areinterchangeable onanoverallreactivity basis.AtSt.LucieUnit2,thisstrategyisusedtotranslate thearrayofunshimmed fuelassemblies andtheirenrichments thathavebeendemonstrated acceptable forthenosolubleboroncondition intoanarrayofburnedfuelassemblies withdifferent initialenrichments, decaytimes,andburnableabsorberconcentrations.

4.6.1Storageoffuelwithhigherenrichments thanthatidentified asacceptable forthenosolubleboroncasereliesoncreditforthedecreaseinfuelassemblyreactivity thatresultsfromreactorpoweroperation.

Toderiveaburnupcreditcurve,aseriesofreactivity calculations areperformed togenerateasetofinitialenrichment/assembly burnuporderedpairswhichallyieldanequivalent k,whenplacedinthespentfuelstorageracks.Anyburnablepoisonspresentinthefuellatticemayalsobefactoredintotheinitialcomposition.

Figures11through15ofEnclosure 1showtheconstantreactivity contoursgenerated forRegionsIandIIoftheSt.LucieUnit2spentfuelstorageracks.Uncertainties associated withburnupcreditincludeanallowance fortheuncertainty intheburnedcomposition ofafuelassemblyanda5%allowance onthecalculated fuelassemblyburnup.Theeffectsonfuelassemblyreactivity ofaxialburnupdistributions havebeenconsidered inthedevelopment ofisotopicconcentrations forburnedfuelassemblies.

Tomaximizetheconversion ratioandthereactivity ofadepletedassembly, St.LucieUnit2fuelassemblies havebeenburnedusingaconservatively hardneutronspectrum.

Comparison ofthereactivity ofanassemblyburnedwiththisharderspectruminthefuelpoolracklatticeandanassemblydepletedatactualUnit2operating conditions showsthatthehardspectrumassemblyisapproximately 0.7%morereactiveatendoflife.Axialreactivity effectsindepletedfuelassemblies areboundedbythisspectralshifttreatment.

Following itsdischarge fromthereactorandthedecayofshortlivedfissionproducts, thereactivity ofaburnedfuelassemblywilldecreaseduetothedecayofactinides andlonghalf-life fissionproducts.

Themostimportant decaychaininvolvesthedecayofPu"'ntoAm"'.Asnotedpreviously, Pu"'

St.LucieUnit2DocketNo.50-389ProposedLicenseAmendment L-97-325Attachment 1Page16of29,isafissileisotopewhichcontributes topositivereactivity athighburnup,whereasAm'4'sprimarily aneutronabsorber.

Withahalf-life ofapproximately 14years,decayofPu"'verthedurationofassemblystorageinthefuelpoolissignificant andcontributes toareduction inbundlek,<<inthefuelpoolenvironment.

Creditforactinidedecayisusedtoreducetheminimumburnuprequiredtomeetreactivity requirements.

Table6ofEnclosure 1summarizes thedecaytime/required burnuporderedpairsasafunctionoffuelassemblyinitialenrichment outtoadecaytimeof20years.Section6.0ofEnclosure 1indicates that170ppmsolubleboronisrequiredtocompensate forreactivity equivalencing methodologies usedatSt.LucieUnit2.4.6.2Thecriticality analysisdescribed inthisevaluation andEnclosure 1wasperformed assumingthatallfreshfuelcontained noburnableabsorbers andthatthemaximumfreshfuelenrichment is4.5w/oU"'.Ifthereactivity hold-downduetothepresenceofburnableabsorbers isconsidered, thenthefreshfuelenrichment canbeincreased above4.5w/ountiltheassemblyreactivity matchesthatofanunshimmed, 4.5w/oassembly.

WhenburnablepoisonsarerequiredatSt.LucieUnit2,fuelloadingpatternstypically utilizeGadolinium (Gd)loadingsof4w/oor6w/o,withbetween4and16burnableabsorberrodsperassembly.

Including anallowance foraxialcutbackoftheGd,theinitialreactivity ofa5.0w/oU"'ssembly withthelightestGdloadingusedinUnit2(4rodsat4w/o)isequaltothereactivity ofafresh,unshimmed 4.5w/oassembly.

Afresh5.0w/oassemblycontaining anyGdshimloadingabovetheminimumwillbelessreactivethanafresh,unshimmed 4.5w/oassembly.

AstheGddepletes, thekoftheshimmed,5.0w/oassemblywillapproachandeventually crossabovethereactivity burndownofanunshimmed 4.5w/oassembly.

Atexposures lessthanthiscrossover pointthe5.0w/ogadolinium

'assembly canreplaceanyfresh4.5w/oassembly.

Atexposurevaluesgreaterthanthiscrossover point,burnupversusenrichment curves(Figures11through15ofEnclosure 1)mustbeadjustedusingFigures16and17ofEnclosure 1todetermine therequiredassemblylocationinthespentfuelpool.FPLisnotrequesting anincreaseinthespentfuelpoolTechnical Specification enrichment limitatthistime.

St.LucieUnit2DocketNo.50-389ProposedLicenseAmendment L-97-325Attachment 1Page17of294.7POSTULATED ACCIDENTS Theproposedstorageconfigurations ofbothRegionIandRegionIIracksatSt.LucieUnit2havebeenexaminedtoidentifypotential accidents thatcouldresultinanincreaseintherackmultiplication factor.Mostaccidentconditions willnotresultinanincreaseinrackk,<<.Forexample,afuelassemblydropaccidentthatresultsinanassemblylyingacrossthetopofthestoragemoduleswillnotresultinanysignificant increaseink,<<ofthesystemduetothelargeseparation distancebetweentheactiveregionoffuelassemblies withinthespecified storagelocations andthefuelassemblylyingatopthemodules.However,twoaccidents canbepostulated thatcouldincreasereactivity beyondtheanalyzedcondition:

(1)atotallossofthefuelpoolcoolingsystemor,(2)themisloadofanassemblyintoacellforwhichrestrictions onburnup,enrichment orlocationarenotsatisfied.

Foranoccurrence ofeitherofthesepostulated accidentconditions, thedoublecontingency principle ofANSI/ANS8.1-1983canbeapplied.Thisstatesthatitisnotnecessary toassumetwounlikely, independent andconcurrent eventstoensureprotection againstacriticality accident.

Thus,forthesepostulated accidentconditions, thepresenceofadditional solubleboroninthefuelpoolwater(abovetheconcentration requiredtoensure95/95conditions andburnupcredit)canbeassumedasarealistic initialcondition becausenotassumingitspresencewouldrepresent asecondunlikelyevent.Thetotallossoffuelpoolcoolinghasthepotential ofincreasing thetemperature ofthepoolcoolanttoboilingconditions.

Calculations performed forboth0ppmand350ppmconditions showedthatthechangeinkwaslessthan0.0040forthe0ppmcaseand0.0066forthe350ppmcase.Thesereactivity valuesreflectanincreaseinfuelpooltemperature from155'Fto240'F.Avarietyofscenarios wereexaminedtoassesstheconsequences ofapostulated fuelassemblymisloadevent.Eachscenarioinvolvedthemisplacement ofafresh,unroddedandunshimmed 4.5w/ofuelassembly.

Threetypesofmisloadpositions wereidentified forthisassembly:

amisloadintoapositionreservedfora4.5w/ofreshfuelassemblycontaining aCEA;amisloadintoapositiondesignated forahighlyburned(1.3w/ofreshfuelequivalent) fuelassembly; andamisloadintoselectedwatercelllocations.

Thelargestbkobservedforanyofthepostulated assemblymisloadswas0.1016foratype3misload.Type1assemblymisloadsresultedinhkvalueslessthan

St.LucieUnit2'ocket8o.50-389ProposedLicenseAmendment L-97-325Attachment 1Page18of2950%aslargeasatype3misload;type2misloadsgenerated h,kvaluesapproximately:75%

aslargeasthetype3misload.Acomparison ofthereactivity valuespresented abovedemonstrates thatthepotential increaseink,<<duetoamisloaded fuelassembly'is substantially greaterthantheincreaseink,duetoalossofallfuelpoolcooling.Theboronconcentration requiredtocompensate forthe>10%increaseink,<<duetothelimitingassemblymisplacement hasbeendetermined tobe746ppm.4.8CRITICALITY ANALYSIS-CONCLUSIONS Section6ofEnclosure 1summarizes thefuelpoolsolubleboronrequirements fortolerances anduncertainties, reactivity equivalencing andpostulated accidents.=

Thesumoftheserequirements totals1266ppm.St.LucieUnit2Technical Specification 5.6.1requiresthatthespentfuelpoolcontainatleast1720ppmsolubleboronatalltimes.ThisTechnical Specification requirement isgreaterthanthetotalfuelpoolsolubleboronrequirement fromEnclosure 1..Thus,currentTechnical Specifications willensurethatk,<<oftheproposedspentfuelpoolstorageconfiguration willbemaintained (0.95inthepresenceofthemostadverseassemblymisloadevent.Assummarized inSection4.5ofthisevaluation, thespentfuelstoragerackarraywasdetermined toremainsubcritical with0ppmsolubleboronata95/95probability/confidence level,considering theeffectofallapplicable biasesanduncertainties.

Inthepresenceof350ppmsolubleboronthe95/95k,ofthisarraywasdetermined tobe(0.95,including applicable biasesanduncertainties.

Thus,theproposedspentfuelpoolstoragearrayconformswithacceptance criteriaprovidedinReference 2.5.0TheSt.LucieUnit2spentfuelstorageracksandfuelpoolstructure aredesignedtowithstand forcesgenerated bynormalplantoperation aswellasthoseforcesgenerated duringaseismicevent.Exceptfortheremovalofcertainstoragecellblockingdevices,theproposedlicenseamendment doesnotinvolveanychangetotheexistingstorageracks.Theanalysessupporting St.LucieUnit2DocketNo.50-389ProposedLicenseAmendment L-97-325Attachment 1Page.19of29theuseofthesestorageracksatUnit2weredeveloped aspartofapoolreracking licenseamendment submitted totheNRCin1984(Reference 4);theirvaliditywasindependently confirmed bytheNRC(Reference 5).Theseanalyseshavebeenexaminedtodetermine ifthe'change instoragecapacityproposedherewouldadversely impacttheirconclusions orresultinanunanalyzed condition.

Thecalculational reviewisformallydocumented inthe"QAReviewofSt.LucieUnit2SpentFuelPoolCapacityIncrease,"

ABBCombustion Engineering NuclearOperations DesignAnalysisNumber:A-SL2-FE-0064,Rev.02,6/12/95,andisavailable fromtheplantrecords.The1984analysesconsidered partialloadingsofthespentfuelrackconsistent withthepresentRegionIandRegionIIstorageconfigurations.

Theseanalysesalsoconsidered thecompleteloadingofallstoragelocations withinthefuelrackswithoutregardtotheRegionIorRegionIIstoragelimitations.

The1984analysesutilizeda"consolidated" fuelweight(approximately equaltotwicetheweightofasinglefuelassembly) ineachstorageracklocationtoconservatively estimatetheresulting loadsonthespentfuelrackstructure andthefuelpoolfloor.Therefore, theassumedweightperstoragecelllocation, andtheresulting structural andseismicanalysesofrecordareconservative c'ompared totheresultsthatwouldbeobtainedforasinglefuelassembly.

Asdiscussed inSection3.1.5ofthis'evaluation, aconservative calculation ofthemaximumfuelpooltemperature resulting fromacompleteoff-loading ofthereactorcoreproducedawatertemperature (T.)ofapproximately 155'Fwithtwocoolingpumpsinoperation.

Section4.4ofReference 4definesT.asthehighesttemperature associated withthepostulated abnormaldesignconditions.

Thisnewlycalculated valueofT.isgreaterthanthe150'FvalueforT.usedinthe1984seismicanalysis.

Theimpactofthis5'Ftemperature increaseonstoragerackstresseswasexaminedusingSectionIIIofthe'f983ASMEcode.Toensureboundingresults,rackstresseswereevaluated assumingafuelpooltemperature of300'F.Theresultsofthisevaluation aregiveninTable1ofthisevaluation.

Theseresultsshowthatfortheplatesandsupportbarsthatcomprisethespentfuelpoolracks,stressintensities arelessthanallowable valuesforbothnormalandfaultedconditions at300'F.Theevaluation ofahigherT.valuewasperformed toensureacceptable rackstressesunderworstconditions.

However,asnotedpreviously actualfuelpooltemperatures duringcoreoffloadevolutions willbelimitedtoamaximumof150'F;therefore thepreviousanalysisofrecordfortheracksandthefuelpoolstructure remainsbounding.

St.LucieUnit2DocketNo.50-389ProposedLicenseAmendment L-97-325Attachment 1Page20of29Theresultsofthisreviewdemonstrate thattheSt.LucieUnit2spentfuelracksandfuelpoolfloorarequalified fortheincreased storagecapacityproposedinthislicenseamendment.

6.0 Asdiscussed

inSections4.5and4.6,therevisedfuelpoolcriticality analysiscreditsthepresenceof520ppmsolubleborontoensurethatk,<<forthenewstorageconfiguration remains~0.95including theeffectsofuncertainties, biasesandreactivity equivalencing.

Becausecreditforfuelpoolsolubleboronisassumed,itisnecessary toidentifytheplantsystemsinterfacing withthespentfuelpoolthatcould,throughamalfunction or.operatorerror,crediblyinitiateadilutionevent.Thisdilutionanalysishasbeenperformed toensurethatsufficient timeremainsavailable todetectandmitigateadilutioneventbeforethespentfuelpoolcriticality analysisdesignbasisvalueofk.<<~0.95isviolated.

Enclosure 2tothisevaluation containsadditional detailsontheevaluation oftheseinterfacing systems,including aquantification ofthetimerequiredforthelossofreactivity margintok,<<--0.95.6.1DESCRIPTION OFMETHODOLOGY Theborondilutionanalysisperformed forSt.LucieUnit2includesanevaluation ofthefollowing plant-specific features:

DilutionSourcesBorationSourcesFuelPoolInstrumentation FuelPoolRelatedPlantProcedures

St.LucieUnit2DocketNo:50-389ProposedLicenseAmendment L-97-325Attachment 1Page21of29PipingImpactofaLossofOffsitePowerBoronDilutionInitiating EventsBoronDilutionTimesandVolumesBasedonareviewofthesystemsthatinterface withthespentfuelpool,eachpotential dilutionpathwasidentified.

Next,theactivities requiredtochangeeachpotential dilutionpathintoanactualfuelpooldilutionpathweredetermined; thisdetermination includedidentifying theplantprocedure(s) thatcontrolled eachevolution.

Thequantityofmakeupavailable tothefuelpoolthrougheachdilutionpathwaywasdetermined andcomparedtothequantityofunborated waterrequiredto'dilute thefuelpooltoak,<<--0.95.Anupperboundflowratethrougheachdilutionpathwaywasdetermined.

Available sourcesofboratedmakeuptothefuelpoolwerealsoidentified.

Foreachdilutionpath,thetimerequiredtoreachthefuelpooldesignvalueofk,<<wascomparedtothefrequency offuelpoolboronsamplingandthefrequency ofoperatorroundsinthevicinityofthespentfuelpool.Anylocalorcontrol'room indications thataninadvertent dilutionmightbeinprogresswerealsoidentified.

Theeffectofapotential lossofoffsitepoweronfuelpooldilutionandborationpathwayswasidentified.

6.2BORONDILUTIONINITIATING EVENTSTheinitialscreening offuelpooldilutionpathwaysidentified sixpotential dilutionscenarios requiring additional review.Theseare:PrimaryWaterSystemmakeupthroughvalveV-15322PrimaryWaterSystemmakeupthroughvalveV-15538PrimaryWateradditionthroughresinflushline St.LucieUnit2DocketNo.50-389ProposedLicenseAmendment L-97-325Attachment 1Page22of29PrimaryWateradditionthroughlocalfirehosestationPrecipitation eventthroughopenFHBL-shapedDoorDilutions resulting fromSeismiceventsorrandompipebreaksSubsequently, FPLevaluated eachofthepotential eventinitiators ingreaterdetailtodetermine whethereachinitiator posedacrediblechallenge tofuelpooldesignreactivity margin.6.3RESULTSOFINITIATING EVENTSFollowing adetailedreviewtwopotential dilutionpathshadcharacteristics thatwarranted consideration asapotential challenge tofuelpoolreactivity margins.Forthesepathways, thetimerequiredtoachieveadilutionsuchthatk,<<=0.95wasquantified.

Onepathwayexaminedwastheprocedurally-specified makeupflowpaththroughvalveV-15538.Assuminganinitialfuelpoolboronconcentration equaltotheTechnical Specification limitof1720ppm,morethan79hourswouldberequiredtodilutethepooltoak,<<of0.95usingthisflowpath.

Assuminganinadvertent dilutionofthefuelpoolthroughtheresinflushline,approximately 60hoursisrequiredtoreducethepoolboronconcentration fromaninitialvalueof1720ppmtoavaluesuchthatfuelpoolk.<<--0.95.Asdiscussed inEnclosure 2,thisquantityofmakeup,throughanyflowpathwithoutacoincident letdownflow,wouldresultintheoverflowofthefuelpool.Thisoverflowontothefuelpooloperating deckwouldbereadilyobservedbyoperations personnel duringtheiron-shiftrounds;atleastsevensetsofoperatorroundswouldbemadeduringthetimethisdilutionwasinprogress.

6.4SPENTFUELPOOLDILUTIONEVENTCONCLUSIONS TheborondilutionanalysisoftheSt.LucieUnit2spentfuelpooldiscussed inEnclosure 2ofthisevaluation hasconcluded thatanunplanned orinadvertent dilutionofthefuelpoolboronconcentration from1720ppmtoconditions such St.LucieUnit2DocketNo.50-389ProposedLicenseAmendment L-97-325Attachment 1Page23of29thatk,<<=0.95isnotacredibleevent.Thisconclusion isbasedonthefollowing:

'Morethan358,900gallonsofunborated waterisrequiredtodilutetheUnit2spentfuelpooltothedesignk,<<valueof0.95.Toactuallyachievethisdilution,'lant personnel wouldberequiredtotakecontinued, manualactionstoassurethisquantityofwaterwouldbedelivered tothespentfuelpool.2.Thenormalmakeuppathtothespentfuelpoolfromtheprimarywatersystem(V-15538) ismaintained lockedclosed.Thealternate primarywatermakeuppathiscapped.3.In-placeadministrative controlsontheprimaryletdownpathfromthespentfuelpool(thereturnlinetotheRWT)ensurethatanyprolonged, inadvertent fuelpoolmakeupwouldresultinpooloverflow.

4.Thelargevolumeofwaterrequiredtoachievethisdilutionwouldbereadilydetectedbyplantpersonnel throughinstalled alarms,overflowofthespentfuelpoolandfloodinginthefuelhandlingbuilding, orbyoperations personnel ontheirnormalroundsonthespentfuelpooloperating deckandelsewhere intheplant.5.Available flowratestodeliverunborated watertothespentfuelpoolensurethatsufficient timeisavailable foroperations personnel todetectandrespondtoanydilutionevent.7.0FPLhasreviewedtheenvironmental impactsoftheproposedlicenseamendment.

Thisreview'demonstrates thattheoverallradiological andnonradiological impactsoftheproposalareinsignificant.

Thereviewissummarized below.7.1THERMALIMPACTThethermalanalysisoftheeffectoftheproposedchangeonthespentfuelpoolcoolingsystemispresented inSection3.1.5ofthisevaluation.

Thatanalysisincludedadetermination ofthemaximumspentfueldecayheatloadfollowing apartialcoreoffloadandafullcoreoffload.Theproposedincrease St.LucleUnit2DocketNo.50-389ProposedLicenseAmendment L-97-325Attachment 1Page24of29instoragecapacitywillchangethemaximumdecayheatloadforapartialcoreoffloadfrom16.9E6Btu/hrto19.76E6Btu/hrandforfullcoreoffloadconditions from31.7E6Btu/hrto35.22E6Btu/hr.Thisincreased heatloa'dresultsinanincreaseofapproximately 3'Finthemaximumfuelpoolwatertemperature forthepartialcoreoffloadcase,andanincreaseofapproximately 5'Finwatertemperature forstorageofthelimitingfullcoreoffload(note:maximumfuelpooltemperature willbemaintained s150'F).Becausetheevaporation ratefromthepoolisassumedtobezero,theincreased decayheatloadisalsotheincreased loadonthecoolingsystemandtheincreased heatrejectedtotheenvironment.

Thetotalheatloadrejectedtotheenvironment bySt.LucieUnit2isabout6.2E9Btu/hr.Thepercentage increaseintheheatrejectedtotheenvironment duetotheincreaseinspentfuelstoragecapacityisontheorderof0.05%forpartialcoredischarges and0.06%forfuelstoragefollowing afullcoreoffload.07.2RADIOLOGICAL EVALUATION 7.2.1Theneteffectofincreasing theSt.LucieUnit2spentfuelpoolstoragecapacityisthatolderfuelelementswillberetainedinwetstoragebeyondthetimewhentheywouldhaveotherwise beenloadedintocasksfordrystorageon-site.Theconcentration ofradionuclides inthespentfuelpooliscontrolled bytheactionsofthefuelpoolpurification systemandbythedecayofshort-livedradioactive isotopes.

Mostofthecontamination collected bythefuelpoolpurification systemoriginates eitherfromdischarged fuelfreshlyemplacedinthefuelpoolorfromtheintermixing ofspentfuelpoolwaterwithprimarywaterduringrefueling evolutions.

Retaining already-aged fuelinwetstorageforanextendedperiodwillnotappreciably increasetheactivityinthefuelpoolwaterortheamountofsolidradioactive wastewhichmustbedisposedofbecausetheshort-lived isotopesassociated withthesefuelbundleswillhavehadanopportunity,to decay.Therefore, increasing thefuelpoolstoragecapacityasproposedforSt.LucieUnit2willhavenosignificant effectonthequantityofradioactive wastecollected.

7.2.2Storageofadditional quantities oflongdecayeddischarged fuelinthespentfuelpoolwillnotsignificantly increasethereleaseofgaseousfissionproducts

St.LucieUnit2DocketNo.50-389ProposedLicenseAmendment L-97-325Attachment 1Page25of29suchasKr".Fuelrodintegrity atSt.LucieUnit2hasbeenverygood,withmostfuelcyclesevidencing noleakingfuelrods.Additionally, therodpressurewhichtendstoactasdrivingforceforfissionproductrelease,issubstantially decreased afterlongperiodsoffuelcooling.7.2.3Theproposedlicenseamendment doesnotinvolveanychangestothemethodofoperating orrangeofmotionofthespentfuelcaskhandlingcrane.Nomovementofloadsinexcessofthenominalweightofafuelassembly, CEAandassociated handlingtoolispermitted overotherfuelassemblies inthestoragepool.Protection againstdroppingthespentfuelcaskintothespentfuelstoragepoolisprovidedbythebasiclayoutoftheFuelHandlingBuilding.

AsnotedinUFSARSection9.1.4.3.2, additional protection isaffordedbythetrolleybumpersandasetoflimitswitcheswhichworktogetherwithbridgeandtrolleybrakestopreventmovementofthecranehookintotherestricted area.Theproposedamendment willalsonotinvolveanychangesinthemodeofoperating orrangeofmotionofthespentfuelhandlingmachine.Changesinfuelassemblyweightduetotheuseofvalue-added fuelhavebeenevaluated anddetermined tobeacceptable (Reference 8).AsnotedinReference 11,duringmovementofafuelassembly, theloadonthehoistcableismonitored toensurethatmovementisnotrestricted.

Installed interlocks willcontinuetorestrictmovementofthehandlingmachinewhenthehoistiswithdrawing orinserting anassembly.

Theexistinganalysesofrecordpertaining totheradiological consequences ofafuelhandlingaccidentwithintheFuelHandlingBuilding(FHB)andthepostulated dropofaspentfuelcaskjustoutsidetheFHBhavebeenexaminedtoassesstheimpactoftheproposedlicenseamendment, including theuseofthevalue-added fuelpelletdesign.Thereviewisformallydocumented inthe"QAReviewofSt.LucieUnit2SpentFuelPoolCapacityIncrease,"

ABBCombustion Engineering NuclearOperations DesignAnalysisNumber:A-SL2-FE-0064,Rev.02,6/12/95,andinReference 10,bothofwhichareavailable fromFPLNuclearEngineering records.Theassumptions andparameters previously employedinevaluating thefuelmishandling accidentwereconsistent withRegulatory Guides1.13and1,25.Thepreviously analyzedconsequences ofdroppingaspentfuelcaskwere St.LucieUnit2DocketNo.50-389ProposedLicenseAmendment L-97-325Attachment 1Page26of29basedontheguidelines providedinSection15.7.5oftheStandardReviewPlan.BasedontheresultsoftwoORIGEN-II assemblydepletions, FPLhasconcluded thatthegapactivities resulting fromtheuseofvalue-added fuelareessentially identical tothoseresulting fromtheuseofthestandardpelletdesign.FPL'sreviewoftheexistinganalysisofthefuelhandlingaccidenthasconcluded thatthegapactivities providedintheanalysisofrecordforthefuelhandlingaccidentconservatively boundthosevaluesexpectedtooccuratassemblydischarge burnupsofupto60,000MWD/MTU(Reference 1).AsdefinedbySection15.7.4oftheStandardReviewPlan,calculated dosevaluesarewellwithintheguidelines ifthecalculated wholebodydoseiss6remandthe,calculated thyroiddoseiss75rem.Asindicated inTable5-9ofReference 4,theseguideline dosevalueswereeasilyachieved.

FPLhasalsoexaminedtheexistinganalysisofanaccidentinvolving thedropofaspentfuelcaskcontaining 10irradiated fuelassemblies.

Thisreviewhasdetermined thatconservative inputassumptions wereusedandthattheresultsoftheexistinganalysisasshowninTable5-6ofReference 4arewellwithintheacceptance criteriaforaLimitingFault-2event.Increasing thestoragecapacityoftheSt.LucieUnit2spentfuelpoolasdescribed inthisproposedlicenseamendment willhavenoeffectontheradiological consequences ofanassumedfuelmishandling eventorontheconsequences ofthedropofaloadedspentfuelcask.Foreachoftheseevents,thecalculated dosesaresmallrelativetotheguideline values.8.0TheimpactoftheproposedincreaseinSt.LucieUnit2spentfuelstoragecapacityandtheimplications oftheuseofreactivity creditforfuelpoolsolubleboronhavebeenexaminedintheabovediscussion.

Eachoftheimpactsoftheproposedchangehasbeenquantified anddetermined tobewithinacceptable limitsbycomparison toestablished acceptance criteria.

Basedonthisexamination, FPLhasdetermined thattheproposedchangestoSt.LucieUnit2Technical Specifications donotconstitute asignificant hazardsdetermination (seeAttachment 2).

~i St.LucieUnit2DocketNo.50-389ProposedLicenseAmendment L-97-325Attachment 1Page27of299.0SafetyEvaluation bytheOfficeofNuclearReactorRegulation, FacilityOperating LicenseNo.NPF-16;Amendment 21,May29,1987.2.SafetyEvaluation bytheOfficeofNuclearReactorRegulation RelatingtoTopicalC-8-03.WCAP-14416-NP-A; EastinghnusW Nlethndnlngy, Revision1,Westinghouse ElectricCorporation, November1996.4.FPLletterL-84-47(and attachments),

J.W.Williams, Jr.toDarrellG.Eisenhut, St.LucieUnitNo.2DocketNo.50-389,Pra885.6.C.3--30.~Analysis, FloridaPowerandUghtCompany,St.LuciaGenerating StationUnit2,preparedby,FranklinResearchCenter,September 19,1984.ABBCENOComputerProgram,SFPOOLVersion1,Verification andValidation ReportNo.00000-AS95-CC-010, Rev.00,June1,1995.(ABB-Combustion Engineering NuclearOperations) 7.369-373.8.ii0.~'gal:hanges.

(Available fromFPLNuclearEngineering Records)9.St.LucieUnit2UpdatedFSAR,throughAmendment 10.10.ABB-CEletterF2-97-149, R.J.'Land toR.J.Rodriguez (FPL),DisOctober15,1997.(Available fromFPLNuclearEngineering records)012.SafetyEvaluation PSL-ENG-SENS-97-006, Revision1,'f'JEJnads,4-4-97.(Available fromFPLNuclearEngineering records)

St.LucieUnit2DocketNo.50-389ProposedLicenseAmendment SEP~IMag~pacit~oluble J3oraxxCxedif.

L-97-325Attachment 1Page28of29SummaryofSt.LucieUnit2Calculated FuelStorageRackStressIntensities A.CamNormalOperation FaultedOperation Condition PmPm+PbPm+Pb+PeStressIntensity (si)19,71329.67049,414Allowable Stress'si)20,00030,00060,000StressIntensity (si)28.05633,262N/AAllowable Stress'si)30,00045,000N/AAllowable Stressbasedonatemperature of300'F.Notethatallowable stressintensity Smis20,000psiatboth200'Fand300'F.B.Comsembly.'onJIL1983)

At300'FSyoryieldstrength=22,500psi.Theallowable stressfornormaloperation is13,500psi(0.6Sy);thisislessthantheallowable stressforthefaultedcondition (1.2"Sy).Thefaultedcondition stresshasbeencalculated tobe4965psi.Therefore, thespentfuelrackswillmeetallowable stresseswithSFPwatertemperatures of300'F.

St.LucieUnit2DocketNo.50-389ProposedLicenseAmendment SF~~~apacity SatubleJ3ararxCredit L-97-325Attachment tPage29of29Xab~St.IucieUnit2Estimated SpentFuelPoolCapacityRequirements CycleffApproximate CycleStartupDate1/5/96TotalNumberofAssemblies inPoolfromallPreviousCycles628SpacesRequirodforFullCoreReserve217TotalNumberofSpacesNeededDuringthisCycle845ExcessStoragoAvailable Existing'ew Caeci'tCaoaci231N/A105/26/97692217909167NIA12/19/9876421798195379125/27/008362171053233071312/19/0190821711250235145/27/03980217119701631512/19/0410522171269091165/27/0611242171341191712/19/0711962171413'icensedCapacity=1076assemblies

'roposedLicensedCapacity=1360assemblies

St.LucieUnit2DocketNo.50-389ProposedLicenseAmendment SEEZMMDETERMINATION OFNOSIGNIFICANT HAZARDSCONSIDERATION AdaptedfromFPLNuclearEngineering SafetyEvaluation PSL-ENG-SENS-97-083, Revision0,12/17/97.

St.LucieUnit2DocketNo.50-389ProposedLicenseAmendment L-97-325Attachment 2Page1of7DETERMINATION OFNOSIGNIFICANT HAZARDSCONSIDERATION Description ofamendment request:Theamendment willamendTechnical Specification 5.6.1andassociated Figure5.6-1,andSpecification 5.6.3,topermitanincreaseintheallowedSpentFuelPool(SFP)storagecapacity.

Theanalysessupporting thisrequest,inpart,assumecreditforupto1266ppmboronconcentration existingintheSFP.Pursuantto10CFR50.92,adetermjnation maybemadethataproposedlicenseamendment involvesnosignificant hazardsconsideration ifoperation ofthefacilityinaccordance withtheproposedamendment wouldnot:(1)involveasignificant increaseintheprobability orconsequences ofanaccidentpreviously evaluated; or(2)createthepossibility ofanewordifferent kindofaccidentfromanyaccidentpreviously evaluated; or(3)involveasignificant reduction inamarginofsafety.FPLhasdetermined thattheactivities associated withthisproposedlicenseamendment donotmeetanyofthesignificant hazardsconsideration standards of10CFR50.92(c)and,therefore anosignificant hazardsconsideration findingisjustified.

Insupportofthisdetermination, thefollowing background information isprovided, followedbyadiscussion ofeachofthesignificant hazardsconsideration standards presented above.St.LucieUnit2hasasinglespentfuelpoolwithatotalof1584storagecelllocations in2distinctfuelpoolstoragerackregions.RegionIoftheUnit2spentfuelpoolstoragerackscontains448storagecellsonan8.965inchpitch.Presently, 50%(or224)ofthesestoragecellsareavailable tostorefuelwithaninitialenrichment of4.5%U"'rless;theremaining vacantstoragecellsareusedasfluxtrapstocontrolreactivity.

RegionIIofthespentfuelpoolstoragerackscontains1136storagecellsonan8.965inchpitchofwhich75%(or852)arecurrently usable.AsofMay,1997,fivepermanently discharged assemblies arestoredinRegionI;687discharged fuelbundlesarestoredinRegionII.Withthepresentlimitations onstoragecapacityintheUnit2spentfuelpoolandtheexistinginventory ofdischarged assemblies awaitingshipmentoffsitetoaDepartment ofEnergy(DOE)facility, St.LucieUnit2willlosetheabilitytofullyoffloadthereactorcoretothefuelpoolinyear2001;itwilllosetheabilitytodischarge anyspentfuelatallinapproximately 2007.Therefore, toensurethatsufficient storagecapacitycontinues toexistfordischarged fuel,FPLhasperformed analysesto St.Lucie.Unit 2DocketNo.50-389ProposedLicenseAmendment L-97-325Attachment 2Page2of7supportanincreaseintheutilization oftheexistingspentfuelstorageracksatSt.LucieUnit2.Thesenewanalysessupportthestorageofupto1360fuelassemblies inthespentfuelpool,including thepresenceof217assemblies resulting fromacompleteoffloadoftheSt.LucieUnit2reactorcore.Theadditional storagecellsmadeavailable bythisproposedlicenseamendment willpermita6yeardeferralintheneedforon-sitedrystorageofdischarged fuelatSt.Lucie.Deferring therequirement foron-sitedrystorageatSt.LucieUnit2allowsadditional timeforthefullcommercialization ofmulti-purpose canister(MPC)technology priortotheselection ofaspecificcasksystem.Withthislicenseamendment request,FPLproposestomodifytherequirements ofSections5.6.1and5.6.3oftheSt.LucieUnit2Technical Specification DesignEeaturestodescribetherevisedfuelstorageconfiguration inthespentfuelpoolandtoreflectthemaximumstoragecapacityoftherevisedconfiguration.

Thefollowing evaluation demonstrates thattheproposedlicenseamendment involvesnosignificant hazardsconsiderations.

Reference ismadetothediscussion contained intheattachedsafetyevaluation.

Analysestosupporttheproposedfuelpool*capacity increasehavebeendeveloped usingconservative methodology.'he analysisofthepotential accidents summarized belowhasshownthatthereisnosignificant increaseintheconsequences ofanyaccidentpreviously analyzed.

Areviewofrelevantplantoperations hasalsodemonstrated thatthereisnosignificant increaseintheprobability ofoccurrence ofanyaccidentpreviously analyzed.

Thisconclusion isalsodiscussed below.Previously evaluated accidents thatwere'examined forthisproposedlicenseamendment include:FuelHandlingAccident, SpentFuelCaskDropAccident, andLossofallFuelPoolCooling.Therewillbenochangeinthemodeofplantoperation orintheavailability ofplantsystemsasaresultofthisproposedchange;thesystemsinterfacing withthespentfuelpoolhavepreviously encountered boratedpoolwaterand,aredesignedtointeract St.LucieUnit2DocketNo.50-389ProposedLicenseAmendment L-97-325Attachment 2Page3of7withirradiated spentfuelandremovetheresidualheatloadgenerated byisotopicdecay.Theproposedamendment doesnotrequireachangeinthemaintenance intervalormaintenance scopeforthefuelpoolcoolingsystemorforthespentfuelcaskcrane.Thefrequency ofcaskhandlingoperations andthemaximumweightcarriedbythecraneisnotincreased asaresultoftheproposedlicenseamendment.

Thus,therewillbenoincreaseintheprobability ofalossoffuelpoolcoolingorintheprobability ofafailureofthecaskcraneasaresultoftheproposedamendment.

Therewillnotbeasignificant increaseinthefrequency ofhandlingdischarged assemblies inthefuelpoolasaresultofthischange;anyhandlingoffuelinthespentfuelpoolwillcontinuetobeperformed inboratedwater..lf thelicenseamendment isapproved, therewillbeaone-time.

repositioning ofcertaindischarged assemblies storedinthefuelpooltocomplywiththerevisedpositioning requirements, buttheincreased poolstoragecapacitywillpermitthedeferralof'spentfuelhandlingassociated withcaskloadingoperations.

Fuelmanipulation duringtherepositioning activitywillbeperformed inthesamemannerasforfuelplacedinthespentfuelpoolduringrefueling outages.Therewillbenochangesinthemannerofhandlingfueldischarged fromthecoreasaresultofrefueling; administrative controlswillcontinue.

tobeusedtospecifyfuelassemblyplacement requirements.

Therelativepositions ofRegionIandRegionIlstoragelocations willremainthesamewithinthefuelpool.Therefore, theprobability ofafuelhandlingaccidenthasnotbeensignificantly increased.

Theconsequences ofafuelhandlingaccidenthavebeenevaluated.

Theradioactive releaseconsequences ofadroppedfuelassemblyarenotaffectedbytheproposedincreaseinfuelpoolstoragecapacity.

Theyremainboundedbytheresultsofcalculations performed tojustifytheexistingSt.LucieUnit2fuelstorageracksandburnuplimits.Atthelimitingfuelassemblyburnup,radioactive releasesfroma.droppedassemblywouldbeonlyasmallfractionofNRCguidelines.

Theinputparameters employedinanalyzing thiseventareconsistent withthecurrentvaluesoffuelenrichment, discharge burnupanduraniumcontentusedatSt.LucieUnit2andwithfutureuseofthe"value-added" fuelpelletdesign.Thus,theconsequences ofthefuelassemblydropaccidentwouldnotbesignificantly increased fromthosepreviously evaluated.

Thecapability ofthefuelpoolcoolingsystemtohandletheincreased numberofdischarged assemblies hasbeenexamined.

Theimpactofatotallossofspentfuelpoolcoolingflowonavailable equipment recoverytimeandonfuelcladdingintegrity hasalsobeenevaluated.

Forthelimitingfullcoredischarge, sufficient timeremainsavailable torestorecoolingflowortoprovideanalternate makeupsourcebefore St.LucieUnit2DocketNo.50-389.ProposedLicenseAmendment L-97-325Attachment 2Page4of7boiloffresultsinafuelpoolwaterlevellessthanthatneededtomaintainacceptable radiation doselevels..Analysishasshownthatintheeventofatotallossoffuelpoolcoolingfuelcladdingintegrity ismaintained.

Therefore, theconsequences ofalossoffuelpoolcoolingevent,including theeffectoftheproposedincreaseinfuelpoolstoragecapacity, havenotbeensignificantly increased frompreviously analyzedresultsforthistypeofaccident.

Theanalysisofrecordpertaining totheradiological consequences ofthehypothetical dropofaloadedspentfuelcaskjustoutsidetheFuelHandlingBuildingwasexaminedtodetermine theimpactoftheincreased fuelstoragecapacityonthisaccident's results.Theresultsofthepreviously performed analysisweredetermined toboundtheconditions described bytheproposedlicenseamendment, thustheconsequences ofthecaskdropaccidentwouldnotbesignificantly increased asaresult.ofthischange.Itisconcluded thattheproposedamendment toincreasethestoragecapacityoftheSt.LucieUnit2spentfuelpoolwillnotinvolveasignificant increaseintheprobability orconsequences ofanyaccidentpreviously evaluated.

2.Inthislicenseamendment FPLproposestocreditthenegativereactivity associated withaportionofthesolubleboronpresentinthespentfuelpool.SolubleboronhasalwaysbeenpresentintheSt.LucieUnit2spentfuelpool;assuchthepossibility ofaninadvertent fuelpooldilutionhasalwaysexisted.However,thespentfuelpooldilutionanalysisdemonstrates thatadilutionoftheUnit2spentfuelpoolwhichcouldincreasethepoolk,<<togreaterthan0.95isnotacredibleevent.Neitherimplementation ofcreditforthereactivity offuelpoolsolubleboronnortheproposedincreaseinthefuelpoolstoragecapacitywillcreatethepossibility ofanewordifferent typeofaccidentatSt.LucieUnit2,IfAnexamination ofthelimitingfuelassemblymisloadhasdetermined thatthiswouldnotrepresent anewordifferent typeofaccident.

Noneoftheotheraccidents examinedasapartofthislicensesubmittal represent anewordifferent typeofaccident; eachofthesesituations hasbeenpreviously analyzedanddetermined toproduceacceptable results.

St.LucieUnit2DocketNo.50-389ProposedLicenseAmendment L-97-325Attachment 2Page5of.7Theproposedlicenseamendment willnotresultinanyotherchangesinthemodeofspentfuelpooloperation atSt.LucieUnit2orinthemethodofhandlingirradiated nuclearfuel.Thespatialrelationship betweenthefuelstorageracksandthecaskcranerangeofmotionisnotaffectedbytheproposedchange.Asaresultoftheevaluation andsupporting

analyses, FPLhasdetermined thattheproposedfuelpoolcapacityincreasedoesnotcreatethepossibility ofanewordifferent typeofaccidentfromanyaccidentpreviously evaluated.

3.Eh~ra~ately.FPLhasdetermined, basedonthenatureoftheproposedlicenseamendment thattheissueofmarginofsafety,whenappliedtothisfuelpoolcapacityincrease, should~~~addressthefollowing areas:1.FuelPoolreactivity considerations 2.FuelPoolborondilutionconsiderations 3.Thermal-Hydraulic considerations 4.Structural loadingandseismicconsiderations TheTechnical Specification changesproposedbythislicenseamendment, theproposedspentfuelpoolstorageconfiguration andtheexistingTechnical Specification limitsonfuelpoolsolubleboronconcentration providesufficient safetymargintoensurethatthearrayoffuelassemblies storedinthespentfuelpoolwillalways'remain subcritical.

Therevisedspentfuelstorageconfiguration isbasedonaUnit2specificcriticality analysisperformed usingmethodology consistent withthatapprovedbytheNRC.Additionally, thesolubleboronconcentration requiredbycurrentTechnical Specifications ensuresthatthefuelpoolk,<<willbealwaysbemaintained substantially lessthan0.95.TheUnit2criticality analysisestablished thatthek,<<ofthespentfuelpoolstoragerackswillbe(1.0withnosolubleboroninthefuelpoolwater,including theeffectofalluncertainties andtolerances..

Creditforthesolubleboronactuallypresentisusedto.offset uncertainties, tolerances, off-normal conditions andtoprovidemarginsuchthatthespentfuelpoolk,<<ismaintained s0.95.FPLhasalsodemonstrated St.LucieUnit2DocketNo.50-389ProposedLicenseAmendment L-97.-325 Attachment 2Page6of7thatadecreaseinthefuelpoolboronconcentration suchthatk,<<exceeds 0.95isnotacredibleevent.CurrentTechnical Specifications requirethatthefuelpoolboronconcentration bemaintained

>1720ppm.Thisboronvalueissubstantially inexcessofthe520ppmrequiredbytheuncertainty andreactivity equivalencing analysesdiscussed inthisevaluation andthe1266ppmvaluerequiredtomaintaink,<<<0.95inthepresenceofthemostadversemispositioned fuelassembly.

TheSt.LucieUnit2fuelpoolboronconcentration willcontinuetobemaintained significantly inexcessof1266ppm;theproposedlicenseamendment willnotresultinchangesinthemodeofoperation oftherefueling watertank(RWT)orinitsuseformakeuptothefuelpool.Thus,operation ofthespentfuelpoolfollowing theproposedchange,combinedwiththeexistingfuelpoolboronconcentration Technical Specification limitof1720ppm,willcontinuetoensurethatk,<<of.thefuelpoolwillbesubstantially lessthan0.95.Evenifthisnot-credible dilutioneventwastooccur,noradiation wouldbereleased; theonlyconsequence wouldbeareduction ofshutdownmargininthefuelpool.Thevolume'of unborated waterrequiredtodilutethefuelpooltoak,<<of0.95issolarge(inexcessof358,9GGgallonstodilutethefuelpoolto520ppmboron)thatonlyalimitednumberofwatersourcescouldbeconsidered potential dilutionsources.Thelikelihood thatthislevelofwaterusecouldremainundetected byplantpersonnel isextremely remote.Inmeetingtheacceptance criteriaforfuelpoolreactivity, theproposedamendment toincreasethestoragecapacityoftheexistingfuelpoolracksdoesnotinvolveasignificant reduction inthemarginofsafetyfornuclearcriticality.

Calculations ofthespentfuelpoolheatloadwithanincreased fuelpoolinventory wereperformed usingANSI/ANS-5.1-1979 methodology.

Thismethodwasdemonstrated toproduceconservative resultsthroughbenchmarking toactualSt.LucieUnit2fuelpoolconditions andbycomparison ofitsresultstothosegenerated byacalculation usingAuxiliary SystemsBranchTechnical Position9-2methodology.

Conservative methodswerealsousedtodemonstrate fuelcladdingintegrity ismaintained intheabsenceofcoolingsystemforcedflow.Theresultsofthesecalculations demonstrate that,forthelimitingcase,theexistingfuelpoolcoolingsystemca'nmaintainfuelpoolconditions withinacceptable limitswiththeincreased inventory ofdischarged assemblies.

Therefore, theproposedchangedoesnotresult St.LucieUnit2DocketNo.50-389ProposedLicenseAmendment L-97-325Attachment 2Page7of7inasignificant reduction inthemarginofsafetywithrespecttothermal-hydraulic orspentfuelcoolingconsiderations.

Theprimarysafetyfunctionofthespentfuelpoolandthefuelstorageracksistomaintaindischarged fuelassemblies inasafeconfiguration forallenvironments andabnormalloadings, suchasanearthquake, alossofpoolcoolingoradropofaspentfuelassemblyduringroutinespentfuelhandling.

Theproposedincreaseinspentfuelinventory onthefuelpoolandtheexistingstoragerackshavebeenevaluated andshowthatrelevantcriteriaforfuelrackstressesandfloorloadingshavebeenmetandthattherehasbeennosignificant reduction inthemarginofsafetyforthesecriteria.

To'summarize, ithasbeenshownthattheproposedincreaseincapacityoftheexistingSt.LucieUnit2spentfuelpoolstorageracksandtheproposedTechnical Specification changesdonot:1.Involveasignificant increaseintheprobability orconsequences ofanaccidentpreviously evaluated; or2.Createthepossibility ofanewordifferent kindofaccidentfromanyaccidentpreviously evaluated; or3.Involveasignificant reduction inamarginofsafety.Therefore, FPLhasdetermined thattheproposedlicenseamendment involvesnosignificant hazardsconsiderations.