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)

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CATEGORY1REGULAYINFORMATIONDISTRIBUTIOA"YSTEM(RXDS)lgACCESS1ONNBR:9801'070046DOC.DATE:97/12/31NOTARIZED:YESDOCKET,5FACIL:50-389St.;LuciePlant,Unit2,FloridaPower&,LightCo.05000389AUTH.NAMEAUTHORAFFILIATION~~~S~~~~~~~~TALL,J.A.FloridaPowerSLightCo.RECIP.NAMERECIPIENTAFFILIATIONDocumentControlBranch(DocumentControlDesk)

SUBJECT:

ApplicationforamendtolicenseNPF-16byincorporatingattachedTSrev.AmendwillmodifyTS5.6.1&associatedFigure5.6-18TS5.6.3toaccomodateincreaseinallowedSFPstoragecapacity.DISTRIBUTIONCODE:AOOIDCOPIESRECEIVED:LTRIENCL(SIZE:I4(TITLE:ORSubmittal:GeneralDistributionIgNOTES:ERECIPIENTIDCODE/NAMEPD2-3LAWIENS,L.COPIESLTTRENCL1111RECIPIENTIDCODE/NAMEPD2-3PDCOPIESLTTRENCL11INTERNAL:ACRSNRR/DE/ECGB/ANRR/DRCH/HICBNRR/DSSA/SRXBOGC/HDS31111111110NRR/DE/EMCBNRR/DSSA/SPLBNUDOCS-ABSTRACT11111111ERNAL:NOACNRCPDRDENOTETOALL"RIDS"RECIPIENTS:PLEASEHELPUSTOREDUCEWASTE.TOHAVEYOURNAMEORORGANIZATIONREMOVEDFROMDISTRIBUTIONLISTSeORREDUCETHENUMBEROFCOPIESRECEIVEDBYYOUORYOURORGANIZATION,CONTACTTHEDOCUMENTCONTROLDESK(DCD)ONEXTENSION415-2083TOTALNUMBEROFCOPXESREQUIRED:LTTR14ENCL13 IIIgtt FloridaPower&LightCompany.6351S.OceanDrive,JensenBeach,FL34957December31,1997L-97-32510CFR50.90U.S.NuclearRegulatoryCommissionAttn:DocumentControlDeskWashington,D.C.20555Re:St.LucieUnit2DocketNo.50-389ProposedLicenseAmendmentSELStoragaZapPursuantto10CFR50.90,FloridaPower&.LightCompany(FPL)requeststoamendFacilityOperatingLicenseNPF-16forSt.LucieUnit2by'incorporatingtheattachedTechnicalSpecifications(TS)revisions.TheamendmentwillmodifySpecification5.6.1andassociatedFigure5.6-1,andSpecification5.6.3toaccommodateanincreaseintheallowedSpentFuelPool(SFP)storagecapacity.Theanalysessupportingthisrequest,inpart,assumecreditforupto1266ppmboronconcentrationexistingintheSFP.AsdiscussedwiththeNRCStaff,itisrequestedthattheproposedamendment,ifapproved,beissuedbyOctober31,1998.Attachment1isanevaluationoftheproposedTSchanges.Attachment2isthe"DeterminationofNoSignificantHazardsConsideration."Attachment3containsacopyoftheaffectedTSpagesmarked-uptoshowtheproposedchanges.Enclosure1isthe"St.LucieUnit2CriticalitySafetyAnalysisfortheSpentFuelStorageRackUsingSolubleBoronCredit",andEnclosure2isthe"St.LucieUnit2SpentFuelPoolDilutionAnalysis."TheproposedamendmenthasbeenreviewedbytheSt.LucieFacilityReviewGroupandtheFloridaPower5LightCompanyNuclearReviewBoard.Inaccordancewith10CFR50.91(b)(1),acopyoftheproposedamendmentisbeingforwardedtotheStateDesigneefortheStateofFlorida.Pleasecontactusifthereareanyquestionsaboutthissubmittal.Verytrulyyours,J.A.StallVicePresidentSt.LuciePlantJAS/RLDAttachments980i07004b97i23iPDRADQCK05000389,'PDRggOlEnclosures(seenextpage)anFPLGroupcompanyIIIIIIIIIIIIIIIIIIIIIIIII,IIIIIIIIIIII 0IP' St.LucieUnit2DocketNo.50-389ProposedLicenseAmendmentL-97-325Page2

Enclosures:

(1)St.LucieUnit2CriticalitySafetyAnalysisfortheSpentFuelStorageRackUsingSolubleBoronCredit,CENPD-387:ABB-CombustionEngineering,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,FloridaDepartmentofHealthandRehabilitativeServices.

St.LucieUnit2DocketNo.50-389ProposedLicenseAmendmentSHoMtorag~apacity~tubleBoraa&reditL-97-325Page3STATEOFFLORIDA))ss.COUNTYOFST.LUCIE)J~A.Stallbeingfirstdulysworn,deposesandsays:ThatheisVicePresident,St.LuciePlant,fortheNuclearDivisionofFloridaPower5LightCompany,theLicenseeherein;Thathehasexecutedtheforegoingdocument;thatthestatementsmadeinthisdocumentaretrueandcorrecttothebestofhisknowledge,informationandbelief,andthatheisauthorizedtoexecutethedocumentonbehalfofsaidLicensee.J.A.StallSTATEOFFLORIDACOUNTYOf&LLI.C.(CSworntoandsubscribedbeforemethis3~dayofttdfqbyJ.A.Stall,whoispersonallyknowntome.~MnrMSignature,o;fI)ooaryPyric>-QggiofFlorida:s;MYCOMMISSION0CC646163EXPlAESMay12,2001BOIIOEOTHIIVTIefFAINNSURANCE,INO.NameofNotaryPublic(Print,Type,orStamp) 08"I,,t0

~~St.LucieUnit2DocketNo.50-389ProposedLicenseAmendmentEVALUATIONOFPROPOSEDTSCHANGESforST.LUCIEUNIT2SPENTFUELPOOLCAPACITYINCREASEAdaptedfromFPLNuclearEngineeringSafetyEvaluationPSL-ENG-SENS-97-083,Revision0,12/17/97,980107004650-389 St.LucieUnit2DocketNo.50-389ProposedLicenseAmendmentL-97-325Attachment1Page1of2

91.0INTRODUCTION

2.0DESCRIPTIONOFCHANGES3.0THERMAL-HYDRAULICCONSIDERATIONS3.1DecayHeatCalculationsfortheSpentFuelPool3.1~13.1.23.1.33.1.43.1.5PurposeandScopeofCalculationAcceptanceCriteriaDescriptionoftheFuelPoolCoolingSystemCalculationsPerformedResults3.2MaximumFuelCladdingTemperature3.2.1Purpose3.2.2DiscussionandResults4.0REACTIVITYCONSIDERATIONS104.1MethodologyUsedinReactivityCalculations4.2AcceptanceCriteria4.3RegionI-DescriptionofStorageArrangementAnalyzed4.4RegionII-DescriptionofStorageArrangementAnalyzed4.5CalculationalAssumptionsandResults4.6ReactivityEquivalencing4.6.1BurnupandDecayTimeReactivityCredit4.6.2GadoliniumReactivityCredit4.7PostulatedAccidents4.8CriticalityAnalysis-Conclusions5.0SEISMICANDSTRUCTURALCONSIDERATIONS St.LucieUnit2~~DocketNo.50-389ProposedLicenseAmendmentBKSBWML-97-325Attachment1Page2of296.0ASSESSMENTOFPOTENTIALFORINADVERTENTFUELPOOLDILUTION206.16.26.36.4DescriptionofMethodologyBoronDilutionInitiatingEventsResultsofInitiatingEventsSpentFuelPoolDilutionEventConclusions7.0NOSIGNIFICANTENVIRONMENTALIMPACT237.1ThermalImpact7.2RadiologicalEvaluation7.2.1SolidRadwaste7.2.2GaseousRadwaste7.2.3RadioactiveReleasesduetoAccidents

8.0CONCLUSION

S

9.0REFERENCES

2627LlSIOEXLBLESSummaryofSt.LucieUnit2CalculatedFuelStorageRackStressIntensities28St.LucieUnit2EstimatedSpentFuelPoolCapacityRequirements29 St.LucieUnit2DocketNo.50-389ProposedLicenseAmendmentSEP~ragaZapacitL-97-325Attachment1Page3of29EVALUATIONOFPROPOSEDTSCHANGES1.0TheexistingspentfuelstorageracksatSt,LucieUnit2containatotalof1584cells,ofwhich1076arecurrentlyavailableforstorage.TheestimatedstoragecapacityrequirementsareillustratedinTable2.AsofNovember1997,theSt.LucieUnit2fuelpoolcontains692permanentlydischargedfuelassemblies.Bytheyear2001,St.LucieUnit2willhavefilledallfuelpoolstoragelocationsnotreservedforafullcoreoff-loadoffuel;by2006,Unit2willhavelosttheabilitytodischargeanyfuelfromthereactor.ToensurethatsufficientcapacitytostoredischargedfuelassembliescontinuestoexistatSt.LucieUnit2,analyseshavebeenperformedwhichsupportanincreaseinthenumberoffuelassemblieswhichmaybe,storedinthefuelpoolfromthecurrentlimitof1076toanewvalueof1360.Theproposedcapacityincreasewillextendthefull-core-reservestoragecapabilityoftheUnit2fuelpoolfromyear2001toapproximately2007.Finaldisposalfacilitiesforspentfuelwillnotbeavailableuntilatleast2010.Theavailabilityofanycentralizedinterimfacilityforspentfuelstorageisuncertain.AlthoughdrystorageofspentfuelmayberequiredattheSt.Luciesiteinthefutureevenwiththeapprovaloftheproposedlicenseamendment,itisprudenttomaximizethestoragecapabilityoftheexistingfuelpoolpriortoinitiating'helicensingandconstructionofanon-sitedrystoragefacility.DeferringtherequirementfordrystorageatSt.Luciewillpermittheuseofmulti-purposecanisters(MPCs)whicharecurrentlybeingdevelopedandlicensed.UseofMPCsforon-sitefuelstorageandoff-sitefueltransportwillbenefitradiationworkersbyreducingthetotaloccupationalexposureandwillminimizethegenerationoflowlevelradioactivewasteduetodrystorageofspentfuel.2.0FPLproposestomodifySection5.6oftheUnit2TechnicalSpecifications,asshowninAttachment3,topermitanincreaseinthestoragecapacityoftheexistingspentfuelpoolstorageracksfrom1076to1360assemblies.TechnicalSpecificationFigure5.6-1willberemovedandnewFigures5.6-1athrough5.6-1ewillbeaddedtodescribetheassemblyburnuprequirementsforRegionIandIIofthespentfuelpool.Theexistingrequirementforafuelpoolsolubleboronconcentrationof>1720ppmisretained.

St.LucieUnit2DocketNo.50-389ProposedLicenseAmendmentL-97-325Attachment1Page4of29Aspartoftheproposedchange,thepermissiblestorageconfigurationofRegionIwillbemodified;anumberofcellblockingdeviceswillberemovedandthenumberofusableRegionIcellswillincreasefrom224to276.FPLexpectsthatcellblockremovalandsubsequentfuelrepositioningoperationscanbeperformedfollowingNRCissuanceoftheproposedlicenseamendmentwithoutpriorNRCapprovalpursuantto10CFR50.59.RegionIwillretaintheability,foradditionalfuelcycles,toacceptafullcoredischargeofirradiatedfuel.AdditionalpermanentlydischargedfuelwhichdoesnotqualifyforstorageinRegionIImayalsobestoredinRegionI.TheproposedamendmentwouldincreasethenumberofusableRegionIIstoragecellsfrom852to1084.JustificationfortheseproposedchangesisprovidedinSections3through7ofthisevaluation.ApprovalofthisproposedlicenseamendmentbytheNRCmayrequireFPLtorequestamodificationtoitscurrentexemptionfromtherequirementsof10CFR70.24.Criterion4oftheexemptionfrom10CFR70.24requiresak,<<of0.95forunboratedwaterinthespentfuelpool.NRCrulemakingactivityisunderwaywhichwillobviatetheneedforanexemptionmodificationrequest.3.0Thethermal-hydraulicanalysisisformallydocumentedinthe"St.Lucie2SpentFuelPoolThermalHydraulicAnalysis,"ABBCombustionEngineeringNuclearOperationsCalculationNumber:016-AS95-C-009,Rev.0,6/09/95,andisavailablefromFPLNuclearEngineeringrecords.3.1DECAYHEATCALCULATIONSFORTHESPENTFUELPOOL3.1.1BecauseFPLisproposingtoincreasethequantityofspentfuelthatmaybestoredinthefuelpoolwithoutmakinganymodificationstothefuelpoolorthefuelpoolcoolingsystem,itisnecessarytoensurethattheexistingequipmenthassufficientheatremovalcapacitytohandletheincreasedload.Inthecourseofperformingtherequiredcalculations,FPLincludedtheeffectsofapotentiali~creaseinthenumberofassembliespermanentlydischargedateachrefuelingoutageintheevent24monthlongoperatingcyclesareimplemented.Theselongercyclesmayresultinincreasedbatchaveragedischargeburnups St.LucieUnit2DocketNo.50-389ProposedLicenseAmendmentL-97-325Attachment1Page5of29whichwerealsoaccountedforintherevisedcalculations.TheABB-CEPCcomputercodeSFPOOL(Reference6)wasusedtoperformmostcalculationsdiscussedinSection3ofthisevaluation.Toensurethatthemethodologychosenforcalculationofthedecayheatloadproducedconservativeresults,aseriesofbenchmarkcalculationswereperformedbasedontheconditionsexistinginthespentfuelpoolasofOctober1,1994.Onthatdate,544dischargedassemblieswerestoredinthespentfuelpool.Theinitialenrichments,operatinghistoriesanddischargeburnupsoftheseassembliesarewellknown.3.1.2recceTheperformanceofthefuelpoolcoolingsystemandthefuelpooltemperaturevaluesderivedfromthisreanalysiswerecomparedtothecriteriagiveninupdatedFSARsection9.1.3.3:Foranormalrefuelingevolution,themaximumfuelpooltemperatureremainsatorbelow150'F;wheremaximumtemperaturevaluesfromthereanalysisexceededthe150'FvaluegivenintheFSAR,anadditionalreviewoftheanalysisofrecordforthefuelstoragerackstructurewasundertakentoensurethatacceptablestresslevelsforrackcomponentswerenotexceeded.Themaximumfuelpooltemperaturefollowingthelimitingpostulatedfullcoreoffloadevolutionwasdeterminedtoremainlessthanboiling.NormalrefuelingevolutionsatSt.LucieUnit2currentlyemployfullcorefueloffloads.Compliancewithpooltemperaturelimitsisensuredthroughtherequiredinitialconditionsspecifiedinaseparate10CFR50.59safetyevaluation(Reference12);typicalconstraintsincludelimitsonthefuelcoolingtimepriortooffloadinitiation,therateofdefuelingtothefuelpool,andthemaximumtemperatureoftheultimateheatsink.FollowingapprovalofthisPLAbytheNRC,Reference12willberevisedandusedtolimitspentfuelpooltemperaturefollowinganyplannedfullcoreoffloadto~150'F.3.1.3TheFuelPoolCoolingSystemprovidescontinuouscoolingforspentfuelassembliesstoredinthefuelpool~Thispermitsstorageofspentfuelassembliesinthepoolfromthetimethefuelisunloadedfromthereactorvesseluntilitisloadedintocasksforshipmentoffsiteoron-sitedrystorage.

St.LucieUnit2DocketNo.50-389ProposedLicenseAmendmentL-97-325Attachment1Page6of29TheSt.LucieUnit2fuelpoolcoolingsystemincludestwofuelpoolheatexchangerscooledbyshellsidecomponentcoolingwaterandtwofuelpoolpumpspoweredfromseparatemotorcontrolcentersprovidingforcedcirculation.Eachfuelpoolpumphasadesignflowrateof1500gpm.Consideringthevolumedisplacedbyafullloadingofspentfuel,thenetfuelpoolliquidvolumeisapproximately300,000gallonsincludin'gthefuelcaskarea.Thecaskloadingareaisthermallyandhydraulicallycoupledtotheremainderofthefuelpool~Suctionforthefuelpoolheatexchangerisdrawnfromnearthetopofthepoolandisreturnedafterbeingcooledthroughpipingwhichdischargesnearthebottomofthepool.Normally,onefuelpoolheatexchangerandonefuelpoolpumpareinservice;twopumpsmaybealignedtooneheatexchangerifdesired.Todate,noheatexchangertubeshavebeenpluggedasaresultofthecoolingsystem'soperation.RedundantfuelpooltemperatureandlevelsensorsprovidelocalreadingsandalarmindicationsintheUnit2controlroom.FuelpoolpumpsandheatexchangersarelocatedintheFuelHandlingBuildingbutarenotlocatedinthevicinityofthefuelpool.AdditionaldetailsonthefuelpoolcoolingsystemmaybefoundinupdatedFSARsection9.1.3.3.14Inevaluatingthecapabilityofthefuelpoolcoolingsystemtohandletheincreasedcoolingload,fourseparatecalculationswereperformed.Thesewereselectedtodemonstratethatmodelingofthepoolcoolingsystemandstoredassembliesproducedconservativeresultsunderavarietyofconditions.Sensitivitystudieswereperformedfortwoofthesecalculations(cases1&2)toquantifysourcesofconservatisminthemethodology'.Case1involvedabenchmarkofthecomputercodecalculatedresultstofuelpoolcoolingsystemdatacollectedinOctober,1994.Actualdischargedassemblyburnupandenrichmentinformationwasusedinthiscomparison.Sensitivitystudieswereperformedtoevaluatetheeffectsofthe2ouncertaintyonpower,evaporativecoolinglossfromthewatersurface,abestestimateheattransfercoefficientacrosstheheatexchangers,andacombinationofthesethreefactors.InCase2,acomparisonwasperformedbetweentheresultsoftheexistinganalysisofrecordforSt.LucieUnit2(whichusestheNRCAuxiliarySystemsBranchTechnicalPosition9-2)andtheequivalentscenariousingthemethod St.LucieUnit2DocketNo.50-389ProposedLicenseAmendmentL-97-325Attachment1Page7of29documentedinANSI/ANS-5.1-1979.AsensitivitystudywasperformedusingtheANSI/ANSmethodologytoquantifytheeffectonfuelpooltemperatureofassumptionsconcerningburnupofthefueloffloadedfromthecore.Case3calculatedthefuelpooltemperatureresultingfromtheplacementofafullcoreofoffloadedfuelintothespentfuelpool7daysafterreactorshutdownwiththefuelpoolalreadycontaining1300previouslydischarged.assemblies.Thiscaseusedlimitingvaluesforbatchaverageandfullcoredischargeexposures.Case4determinedthefuelpooltemperatureresultingfromthedischargeofarefuelingbatchof96assemblies5daysafterreactorshutdownconcurrentwithanactivefailureinthefuelpoolcoolingsystem.Thetotalfuelpoolloadingforthiscasewas1492assemblies,thusprecludingafullcoreoffload.Foreachcase,thefuelpoolwaterboiloffratewasalsodeterminedassumingatotallossof.fuelpoolcooling,Thisratewasusedtoquantifythetimeavailableforsystemrepairsorotherremedialactionpriortoadecreaseinfuelpoolwaterleveltoapoint9feetabovethetopofthefuelseatedinthestorageracks.Subsequenttothesecalculations,Reference10evaluatedtheimpactoftheuseoftheABB-CE"value-added"fueldesignonthisanalysis.3.1.5BesultsCase1demonstratedthatthemodelingschemechosentorepresentthefuelpoolproducedatemperatureapproximately7'Fhigherthanthatgivenbyactualplantdata.Calculationsprovidedanexpectedfuelpooltemperatureof92.8'F;plantdataprovidedafuelpooltemperatureof86.0F.Whenbestestimateevaporativelosses,heattransfercoefficients,andtheremovalofthe2o'ecayheatuncertaintywereconsidered,thepredictedfuelpooltemperaturedecreasedto91.1'F,thusdemonstratingtheconservativenatureofthemodelingofthefuelpoolanddischargedfuel.ANSI/ANS-5.1-1979decayheatmethodologywasusedthroughoutthiscalculation.Case2demonstratedthatthesimplifiedANSI/ANS-5.1-1979decayheatmethodologyproducesahighercalculatedfuelpooltemperaturevaluethandoesNRCBranchTechnicalPosition9-2.ThiscaseanalyzedasituationwheretheUnit2fuelpoolcontains1113dischargedfuelassemblies,includingafull St.LucieUnit2DocketNo.50-389ProposedLicenseAmendmentL-97-325Attachment1Page8of29coredischargewhichhascooledfor7days.Resultsgivetemperaturevaluesof154.2'FwithtwofuelpoolpumpsoperatingusingtheANSI/ANSmethodologyascomparedtoapreviouslyreportedvalueof(150'F.Case3demonstratedthatforafuelpoolcontaining1517assemblies,including217fuelbundlesoffloadedfromthecore7daysfollowingreactorshutdown,themaximumfuelpoolwatertemperaturewas170.9'Fwithonefuelpumpinoperationand154.9'Fwithbothspentfuelpumpsinoperation.Theresultantheatloadforthiscasewas35.22E6Btu/hrincludinguncertainties.ActualdischargeexposureswereusedforfuelplacedinthespentfuelpoolpriortoJune1995;fueldischargessubsequenttothistimeweremodeledusingconservativecumulativeexposurevaluesincludingavalueof55,000MWD/MTUforeachofthe217assembliesoffloadedfromthecore.PursuanttotheguidanceinNUREG0800,thiscalculationhasdemonstratedthatnospentfuelpoolbulkboilingoccursandthus,thecriteriaofNUREG0800,Section9.1.3issatisfied:TheanalysesdiscussedinSections3.1.4and3.1.5ofthisevaluationcontainanumberofconservatismswhencomparedtotheactualplantconditionsthatwillexistfollowingapprovaloftheproposedlicenseamendment(seeaboveparagraphs).Theseconservatismstendtoincreasethecalculatedmaximumfuelpooltemperature.ThemaximumspentfuelpoolwatertemperaturefollowinganyplannedfullcorefueloffloadatSt.LucieUnit2willbemaintaineds150'FbytheplantrestrictionsspecifiedinReference12.This150'FvalueisconsistentwiththefuelpooltemperaturelimitgiveninNUREG0843(St.LucieUnit2SER)followingafullcoreoffloadwithtwocoolingpumpsinoperation.Foratotallossoffuelpoolcooling,Case3providesthelimitingfuelpoolboil-offrate.Forthiscasetheboil-offratewasdeterminedtobe73.3gallons/minute.Atthisrateofboil-off,37.9hoursarerequiredforthepoolwaterleveltodropto9feetabovethetopoffuelseatedinthestorageracks.Case4demonstratesthatforaseriesofpartialcoreoffloadsandusingboundingparametersforassemblyburnup,fissionproductgeneration,andfuelpoolcoolingsystemheattransfer,theresultingfuelpoolwatertemperatureremainslessthan150'F.Themaximumheatloadcalculatedforthiscase,includingtheeffectofdecayheatuncertainties,was19.76E6Btu/hr.Withallowanceforactivecomponentfailures(bothapumpandheatexchangerassumedunavailable)thefuelpoolwatertemperaturewascalculatedtobe pfII St.LucieUnit2DocketNo.50-389ProposedLicenseAmendmentL-97-325Attachment1Page9of29139.8'F.Consideringonlythesecondheatexchangertobeunavailable(2pumpsfeedingasingleheatexchanger)theresultingpoolwatertemperatureis130.8'F.Bothofthesevaluesarewithinthe150'FcriterionspecifiedinSection9.1.3.3oftheupdated.St.LucieUnit2FSAR.Reference10hasdeterminedthatuseofthevalue-addedfueldesignatSt.LucieUnit2willhavenoadverseeffectontheconclusionsof'thefuelpoolcoolinganalysis.3.2IVIAXIIVIUMFUELCLADDINGTEMPERATURE3.2.1Purpose.Itisimportanttoensurethatfuelrodcladdingintegritywillbemaintainedunderlimitingconditionsinthespentfuelpoolenvironmerit.Todothis,calculationswereperformed,usingconservativeinputs,todemonstratethatfilmboilingdoesnotoccuratthesurfaceofthecladintheeventofa.lossofforcedflowcooling;i.e.theheattransfercoefficientremainswithintherangeofnucleateboiling.3.22Themaximumlocalheatfluxatthefuelrodsurfaceforanassemblydischargedtothefuelpool3daysafterreactorshutdownhasbeencalculatedtobe1980.9Btu/hr-ft'.Thephysicsandgeometryparametersusedasinputtothiscalculation(peakingfactors,rodburnupandroddiameter)wereselectedtomaximizetheheatfluxvalueandtoboundbothcurrentandvalue-addedfueldesigns.Thecalculationofpeakcladdingtemperatureinafuelpoolenvironmentcouplesthemaximumcalculatedsurfaceheatfluxwithanempiricalequationforfreeconvectionthatassumesaconstantcladdingsurfacetemperature.Inthisempiricalequationfluidpropertiesareevaluatedatthesaturationtemperature.Toensureaconservativeresultwhenapplyingthisequation,theaxialpositionofthemaximumdecayheatfluxisassumedtobelocatedatthebottomofthespentfuelassembly.Thesaturationtemperatureatapooldepthcorrespondingtothebottomofthefuelassemblyseatedinthestorageracksis252'F.Forthiscondition,theempiricalcorrelationusedintheSFPOOLcomputercodeproducedapeakfuelcladdingtemperatureof309.2'F.

f1 St.LucieUnit2DocketNo.50-389ProposedLicenseAmendmentL-97-325Attachment1'age10of29Asacheckontheabovecalculatedtemperaturevalue,theRohsenowboilingcorrelation(Reference7)wasalsousedtocalculatethepeakcladdingtemperature.Thecladdingtemperaturecalculatedusingthismethodisconsistentwiththe309.2'Fvaluereportedabove.Thetemperaturevaluescalculatedusingthemethodsandconservativeinputdescribedaboveprovideassurancethatfuelrodcladdingwillbemaintainedintactin'theeventofalossoffuelpoolcooling.4.0ThefollowingsubsectionsdescribetheproposednewconfigurationoftheSt.LucieUnit2spentfuelpool,themethodologyusedtogeneratecalculatedvaluesofreactivityandeffectiveneutronmultiplicationtosupportthisconfiguration,andtheanalysisresults.44.1METHODOLOGYUSEDINREACTIVITYCALCULATIONSCriticalitycalculationstosupporttheproposedincreaseintheSt.LucieUnit2spentfuelpoolstoragecapacityhavebeenperformedbyABB-CEusingmethodologyconsistentwiththatdescribedinWCAP-14416(Reference3).ThisWestinghouseOwnersGroupreportwassubmittedtotheNRCinJuly,1995andwassupplementedinOctober,1996.TheanalysismethodologyusedbyABB-CEintheevaluationofthespentfuelstoragerackconfigurationemploys:(1)SCALE-PC,apersonalcomputerversionoftheSCALE-4.3codepackage(whichincludesKENO-Va,NITAWL,CSAS-2andBON-AMI),withtheupdated44groupENDF/B-5crosssectionlibrary,and;(2)thetwo-dimensionalintegraltransportcodeDITwithanENDF/B-6neutroncrosssectionlibrary.AdetaileddiscussionoftheapplicationofthiscriticalitymethodologymaybefoundinEnclosure1tothisevaluation.BothregionsoftheUnit2spentfuelpoolwillcreditthepresenceofsolubleboron;mostanalysesoftheUnit2poolmodeledbothRegionIandRegionIIexplicitlyinasinglecalculation.4.2ACCEPTANCECRITERIATheSERissuedbytheNRC(Reference2)forsolubleboroncreditmethodologyrequirestheapplicationofatwopartacceptancecriteriatotheSt.LucieUnit ttt St.LucieUnit2DocketNo.50-389ProposedLicenseAmendmentL-97,-325Attachment1Page11of292spentfuelstorageracks.First,the95%probability95%confidence(95/95)valueoftheeffectiveneutronmultiplicationfactor(k,<<)fortheproposedspentfuelstoragearraymustbelessthan1.0whenanalyzedwith0ppmsolubleboron,includingtheeffectofalluncertaintiesandtolerances.Secondly,theacceptancecriteriaforfuelpoolconditionswithsolubleboronpresentrequirethatthe95/95k,<<mustbelessthanorequalto0.95,includingtheeffectofall.uncertaintiesandtolerances..Reactivit'ycalculationsforthespentfuelracksalsoincludetheeffectoftwobiases.Computercodebiasesbasedonthederivedvalueofk,fromKENO-Vacomparedagainstexperimentalbenchmarksareapplied.Inaddition,thereactivityeffectsofpossiblefuelpooltemperaturevariationsencounteredduringnormaloperationareincluded.Enclosure1(anditsreferences)alsoprovidesasummaryofthecomparisonsmadetoexperimentaldatathatwereusedtoderivetheKENO-Vareactivitybiasanduncertainty.Bothcalculationsperformedat0ppmsolubleboronandcalculationswhichcredittheeffectofsolubleborononstoragerackreactivityalsoincludetheeffectsoftolerancesinfuelassemblyenrichment,fabricationandpositioningparameters,fuelrackconstructiontolerances,anduncertaintiesinthecalculationofstoragerackreactivity,controlelementassembly(CEA)worthandassemblyburnup.Inadditiontotheboronconcentrationrequiredtocompensateforuncertaintiesandtolerancesincalculationsofk.<<fornormalstorageconditions,theamountofsolubleboronrequiredtocompensateforpostulatedaccidentconditionsisalsoquantified.4.3REGIONI-DESCRIPTIONOFSTORAGEARRANGEMENTANALYZEDThestoragearrangementforRegionIproposedbythislicenseamendmentpreservesthecapabilitytofullyoffloadfuelfromtheUnit2reactorvesselbyprovidingstoragespacefor276fuelassemblies.TheproposedRegionIstoragegeometryisshowninFigure9ofEnclosure1;adiscussionofthespecificstoragerequirementsforthisregionissummarizedbelow.RegionIcontinuestomakeuseoffluxtrapstoincreaseneutronleakage(andminimizek,<<)throughplacementoffuelnexttoregionsofwater.TwonoteworthydifferencesbetweentheproposedarrangementandtheexistingRegionI

~~~St.LucieUnit2DocketNo.50-389ProposedLicense'AmendmentL-97-325Attachment1Page12of29storagearrangementare:(1)thattheannularwaterregionbetweentheexterioroftherackarrayandthefuelpoolwallservesasanexplicitly-analyzedneutronsink,and(2)thatarowofvacant,water-filledstoragecellscanservetoneutronicallydecoupleregionsoffreshfuelplacedoneitherside.AsshowninFigure9ofEnclosure1,theU-shapedrows(orrings,beginningattheoutsideofthearrayandworkinginward)1,3and9ofRegionIwillhold120fuelbundles(andupto56fullstrengthCEAs)inahigh(89%)densityarray.Themostreactive(orlowestburnup)fuelassembliesfromthecoreoffloadwillbeplacedinthesethreerings,.TheU-shapedrows5,6,8and11areusedtostoretheassembliesfromthecoreoffloadwiththegreatestburnup(orlowestreactivity).Dependingontheirburnup,certainoftheseassembliesmayberequiredtocontainfullstrengthCEAs.Theadditionalstoragelocationsinrows8,11,andthe3by10arrayatthelowercenterofFigure9maybeusedtostorepermanentlydischargedfuelwhichdoesnotmeetthecriteriaforstorageinRegionII.TheU-shapedrows2,4,7and10serve.asfluxtrapsandwillremainvacant.Intherackcriticalityanalysis,mostfuelplacedinrows1,3and9isassumedtohaveaninitialenrichment'of4.5w/oU"';twoassemblieseachinrows1and3andoneassemblyinrow9areassumedtohavea1.82w/oU"'reshfuelequivalent.Theanalysisoffuelstoredinrows5,6,8,11andthe30assemblycenterarrayalsoutilizesaconservativecreditforthereactivitydepletionoftheoffloadedfuelplacedhere.InallcoreoffloadscenariosapplicabletoSt.LucieUnit2,someportionofthefuelwillhaveaccruedappreciableburnupandneednotbeanalyzedasfreshfuel.4,4REGIONII-DESCRIPTIONOFSTORAGEARRANGEMENTANALYZEDTheproposedfuelstoragearrangementforRegionIIofthespentfuelpoolincreasesthestoragedensityoftheregionto95.4%fromthecurrentvalueof75%.AllofRegionIIcontinuestorequireaminimumvalueofassemblyburnupforstorage.Thisrequiredburnupvalueisafunctionoftheinitialfuelassemblyenrichmentanditsdecay(orcooling)time.Therelationshipbetweenfuelcoolingtimeandrequiredburnupisprimarilyduetothe14.3yearhalflifeofPu"'.Overtime,thisfissileisotopedecaystoAm"',whichisprimarilyaneutron.absorber.DecayofPu'4'ddsasignificantamountofnegativereactivitytothefuelpool.

St.LucieUnit2DocketNo.50-389ProposedLicenseAmendmentL-97-325Attachment1Page13of29TheconservativeinitialneutronsourcedistributionassumedforsubcriticalmultiplicationensuresthatRegionIIcontrolsthereactivityoftheentirefuelpool.Toensuresufficientreactivitymargintothe1.0k,<<limit,eachRegionIIrackmoduleretains4vacantinteriorcells,detailedinFigure10ofEnclosure1,whichserveasfluxtraps.TheproposedRegionIIstoragearrangementalsorecognizesthat,becauseofdifferencesinneutronleakage,theburnuprequirementsforfuelstorageintheinteriorofRegionIIaremorerestrictivethanthoseforfuelstorageintheouterrowofRegionIIwhereanassemblyfacesavacantRegionIcell,orfacesthewatergapseparatingthestorageracksfromthefuelpoolwall.SpentfuelrackstoragecellslocatedintheinteriorofRegionIIrequireanassemblyburnupequivalentto1.3w/oU"'reshfuel,priortoanycreditforactinidedecay,topermitfuelstorage.StoragecellslocatedontheperipheryofRegionIIwithatleastonesurfacefacingwaterrequireanassemblyburnupequivalentto1.5w/oU"'reshfuel,priortocreditingactinidedecay.4.5CALCULATIONALASSUMPTIONSANDRESULTSTheassumptionslistedbelowwereusedforSt.LucieUnit2incalculationsofthek,<<applicabletothespentfuelpoolstorageracks:Fuelassembliescontainuraniumdioxideatthenominalenrichmentovertheentirelengthofeachrod.Thereactivityeffectofaa0.05w/ovariationinUO,enrichmenthasbeenincludedinthereactivity'olerancesanduncertainties.2.Fuelrodshavebeenmodeledconsideringthedesigncharacteristicsof.theABB-CE"value-added".pellet,whichisplannedforinsertionintoUnit2forcycle11.Modelingthisdesignconservativelyboundsthecurrentfueldesignrelativetoreactivityequivalencing.Thereactivityeffectsofa2%uncertaintyinthefuelrodstackdensityhavebeenconsidered;thisuncertaintyvalueisconservativecomparedtotheobservedhistoryofvariationsinthisparameter.3.Allfuelassembliesareassumedtocontain236fuelrodsina16x16fuelrodlattice.Table3ofEnclosure1tabulatesthefuelparametersutilizedinthefuelpoolcriticalityanalysis.

St.LucieUnit2DocketNo.50-389ProposedLicenseAmendmentL-97-325Attachment1Page14of294.TolerancesduetouncertaintiesinthethicknessofL-inserts(RegionI)andrackstoragemodulewallshavebeenconsidered.5.Tolerancesduetouncertaintiesinpositioningoffuelassemblieswithinthestoragecellshavebeenconsidered.Fornominalcalculations,fuelassemblieswereassumedtobecenteredwithineachstoragecelltype.UsinginfinitearraysofbothRegionIandRegionIItypecells,thereactivityeffectsofoff-centerassemblyplacementwereexamined.6.Thereactivityeffectsofvariationsinstoragecellinteriordimensions(ID)andcellpitchhavebeenconsidered.7.Themoderatoriswatercontainingeither0ppm(forcomparisonto1.0k,limit)or350ppmsolubleboron(forcomparisonto0.95k,<<limit)atatemperatureof50'F.8,A95/95confidencelevelassessmentofcalculatedCEAworthwasdevelopedforapplicationtotheRegionIstoragerackarray.ThisvaluewasbasedonCEAworthcomparisonsbetweenpredictionsandmeasurementsfromoperatingreactorsandcomparisonsbetweenDITandKENO-Vacalculationsofrodworth.Usingtheseassumptions,theKENO-VamodeloftheSt.LucieUnit2storagerackscalculatedak,of0.97001forthe0ppmsolubleboroncondition,priortotheapplicationofanybiases,tolerancesoruncertainties.Includingtheeffectofthesefactors,theresultingk,<<valueis0.99801.Thisvalueislessthanthe'k~acceptancecriteriavalueof1.0for0ppmconditions.Page30ofEnclosure1providesadetailedtabulationofthereactivityeffectforeachbiasoruncertainty.Table5ofEnclosure1providesadetailedaccountingofthereactivityeffectofeachbiasoruncertaintyforthecalculationofthestoragerackk,<<inthepresenceofsolubleboron.At350ppm,priortoapplicationofanybiasesoruncertainties,k,<<wasdeterminedtobe0.91497.Afterapplicationofallbiases,tolerancesanduncertainties,k,<<equals0.94797.Thisvalueislessthanthe0.95acceptancecriteriaforfuelpoolk,<<inthepresenceofsolubleboron.

St.LucieUnit2DocketNo.50-389ProposedLicenseAmendmentL-97-325Attachment1Page15of294.6REACTIVITYEQUIVALENCINGReactivityequivalencingisusedtodefinetheconditionsunderwhichfresh,burnedandshimmedfuelassembliesareinterchangeableonanoverallreactivitybasis.AtSt.LucieUnit2,thisstrategyisusedtotranslatethearrayofunshimmedfuelassembliesandtheirenrichmentsthathavebeendemonstratedacceptableforthenosolubleboronconditionintoanarrayofburnedfuelassemblieswithdifferentinitialenrichments,decaytimes,andburnableabsorberconcentrations.4.6.1Storageoffuelwithhigherenrichmentsthanthatidentifiedasacceptableforthenosolubleboroncasereliesoncreditforthedecreaseinfuelassemblyreactivitythatresultsfromreactorpoweroperation.Toderiveaburnupcreditcurve,aseriesofreactivitycalculationsareperformedtogenerateasetofinitialenrichment/assemblyburnuporderedpairswhichallyieldanequivalentk,whenplacedinthespentfuelstorageracks.Anyburnablepoisonspresentinthefuellatticemayalsobefactoredintotheinitialcomposition.Figures11through15ofEnclosure1showtheconstantreactivitycontoursgeneratedforRegionsIandIIoftheSt.LucieUnit2spentfuelstorageracks.Uncertaintiesassociatedwithburnupcreditincludeanallowancefortheuncertaintyintheburnedcompositionofafuelassemblyanda5%allowanceonthecalculatedfuelassemblyburnup.Theeffectsonfuelassemblyreactivityofaxialburnupdistributionshavebeenconsideredinthedevelopmentofisotopicconcentrationsforburnedfuelassemblies.Tomaximizetheconversionratioandthereactivityofadepletedassembly,St.LucieUnit2fuelassemblieshavebeenburnedusingaconservativelyhardneutronspectrum.ComparisonofthereactivityofanassemblyburnedwiththisharderspectruminthefuelpoolracklatticeandanassemblydepletedatactualUnit2operatingconditionsshowsthatthehardspectrumassemblyisapproximately0.7%morereactiveatendoflife.Axialreactivityeffectsindepletedfuelassembliesareboundedbythisspectralshifttreatment.Followingitsdischargefromthereactorandthedecayofshortlivedfissionproducts,thereactivityofaburnedfuelassemblywilldecreaseduetothedecayofactinidesandlonghalf-lifefissionproducts.ThemostimportantdecaychaininvolvesthedecayofPu"'ntoAm"'.Asnotedpreviously,Pu"'

St.LucieUnit2DocketNo.50-389ProposedLicenseAmendmentL-97-325Attachment1Page16of29,isafissileisotopewhichcontributestopositivereactivityathighburnup,whereasAm'4'sprimarilyaneutronabsorber.Withahalf-lifeofapproximately14years,decayofPu"'verthedurationofassemblystorageinthefuelpoolissignificantandcontributestoareductioninbundlek,<<inthefuelpoolenvironment.Creditforactinidedecayisusedtoreducetheminimumburnuprequiredtomeetreactivityrequirements.Table6ofEnclosure1summarizesthedecaytime/requiredburnuporderedpairsasafunctionoffuelassemblyinitialenrichmentouttoadecaytimeof20years.Section6.0ofEnclosure1indicatesthat170ppmsolubleboronisrequiredtocompensateforreactivityequivalencingmethodologiesusedatSt.LucieUnit2.4.6.2ThecriticalityanalysisdescribedinthisevaluationandEnclosure1wasperformedassumingthatallfreshfuelcontainednoburnableabsorbersandthatthemaximumfreshfuelenrichmentis4.5w/oU"'.Ifthereactivityhold-downduetothepresenceofburnableabsorbersisconsidered,thenthefreshfuelenrichmentcanbeincreasedabove4.5w/ountiltheassemblyreactivitymatchesthatofanunshimmed,4.5w/oassembly.WhenburnablepoisonsarerequiredatSt.LucieUnit2,fuelloadingpatternstypicallyutilizeGadolinium(Gd)loadingsof4w/oor6w/o,withbetween4and16burnableabsorberrodsperassembly.IncludinganallowanceforaxialcutbackoftheGd,theinitialreactivityofa5.0w/oU"'ssemblywiththelightestGdloadingusedinUnit2(4rodsat4w/o)isequaltothereactivityofafresh,unshimmed4.5w/oassembly.Afresh5.0w/oassemblycontaininganyGdshimloadingabovetheminimumwillbelessreactivethanafresh,unshimmed4.5w/oassembly.AstheGddepletes,thekoftheshimmed,5.0w/oassemblywillapproachandeventuallycrossabovethereactivityburndownofanunshimmed4.5w/oassembly.Atexposureslessthanthiscrossoverpointthe5.0w/ogadolinium'assemblycanreplaceanyfresh4.5w/oassembly.Atexposurevaluesgreaterthanthiscrossoverpoint,burnupversusenrichmentcurves(Figures11through15ofEnclosure1)mustbeadjustedusingFigures16and17ofEnclosure1todeterminetherequiredassemblylocationinthespentfuelpool.FPLisnotrequestinganincreaseinthespentfuelpoolTechnicalSpecificationenrichmentlimitatthistime.

St.LucieUnit2DocketNo.50-389ProposedLicenseAmendmentL-97-325Attachment1Page17of294.7POSTULATEDACCIDENTSTheproposedstorageconfigurationsofbothRegionIandRegionIIracksatSt.LucieUnit2havebeenexaminedtoidentifypotentialaccidentsthatcouldresultinanincreaseintherackmultiplicationfactor.Mostaccidentconditionswillnotresultinanincreaseinrackk,<<.Forexample,afuelassemblydropaccidentthatresultsinanassemblylyingacrossthetopofthestoragemoduleswillnotresultinanysignificantincreaseink,<<ofthesystemduetothelargeseparationdistancebetweentheactiveregionoffuelassemblieswithinthespecifiedstoragelocationsandthefuelassemblylyingatopthemodules.However,twoaccidentscanbepostulatedthatcouldincreasereactivitybeyondtheanalyzedcondition:(1)atotallossofthefuelpoolcoolingsystemor,(2)themisloadofanassemblyintoacellforwhichrestrictionsonburnup,enrichmentorlocationarenotsatisfied.Foranoccurrenceofeitherofthesepostulatedaccidentconditions,thedoublecontingencyprincipleofANSI/ANS8.1-1983canbeapplied.Thisstatesthatitisnotnecessarytoassumetwounlikely,independentandconcurrenteventstoensureprotectionagainstacriticalityaccident.Thus,forthesepostulatedaccidentconditions,thepresenceofadditionalsolubleboroninthefuelpoolwater(abovetheconcentrationrequiredtoensure95/95conditionsandburnupcredit)canbeassumedasarealisticinitialconditionbecausenotassumingitspresencewouldrepresentasecondunlikelyevent.Thetotallossoffuelpoolcoolinghasthepotentialofincreasingthetemperatureofthepoolcoolanttoboilingconditions.Calculationsperformedforboth0ppmand350ppmconditionsshowedthatthechangeinkwaslessthan0.0040forthe0ppmcaseand0.0066forthe350ppmcase.Thesereactivityvaluesreflectanincreaseinfuelpooltemperaturefrom155'Fto240'F.Avarietyofscenarioswereexaminedtoassesstheconsequencesofapostulatedfuelassemblymisloadevent.Eachscenarioinvolvedthemisplacementofafresh,unroddedandunshimmed4.5w/ofuelassembly.Threetypesofmisloadpositionswereidentifiedforthisassembly:amisloadintoapositionreservedfora4.5w/ofreshfuelassemblycontainingaCEA;amisloadintoapositiondesignatedforahighlyburned(1.3w/ofreshfuelequivalent)fuelassembly;andamisloadintoselectedwatercelllocations.Thelargestbkobservedforanyofthepostulatedassemblymisloadswas0.1016foratype3misload.Type1assemblymisloadsresultedinhkvalueslessthan

St.LucieUnit2'ocket8o.50-389ProposedLicenseAmendmentL-97-325Attachment1Page18of2950%aslargeasatype3misload;type2misloadsgeneratedh,kvaluesapproximately:75%aslargeasthetype3misload.Acomparisonofthereactivityvaluespresentedabovedemonstratesthatthepotentialincreaseink,<<duetoamisloadedfuelassembly'issubstantiallygreaterthantheincreaseink,duetoalossofallfuelpoolcooling.Theboronconcentrationrequiredtocompensateforthe>10%increaseink,<<duetothelimitingassemblymisplacementhasbeendeterminedtobe746ppm.4.8CRITICALITYANALYSIS-CONCLUSIONSSection6ofEnclosure1summarizesthefuelpoolsolubleboronrequirementsfortolerancesanduncertainties,reactivityequivalencingandpostulatedaccidents.=Thesumoftheserequirementstotals1266ppm.St.LucieUnit2TechnicalSpecification5.6.1requiresthatthespentfuelpoolcontainatleast1720ppmsolubleboronatalltimes.ThisTechnicalSpecificationrequirementisgreaterthanthetotalfuelpoolsolubleboronrequirementfromEnclosure1..Thus,currentTechnicalSpecificationswillensurethatk,<<oftheproposedspentfuelpoolstorageconfigurationwillbemaintained(0.95inthepresenceofthemostadverseassemblymisloadevent.AssummarizedinSection4.5ofthisevaluation,thespentfuelstoragerackarraywasdeterminedtoremainsubcriticalwith0ppmsolubleboronata95/95probability/confidencelevel,consideringtheeffectofallapplicablebiasesanduncertainties.Inthepresenceof350ppmsolubleboronthe95/95k,ofthisarraywasdeterminedtobe(0.95,includingapplicablebiasesanduncertainties.Thus,theproposedspentfuelpoolstoragearrayconformswithacceptancecriteriaprovidedinReference2.5.0TheSt.LucieUnit2spentfuelstorageracksandfuelpoolstructurearedesignedtowithstandforcesgeneratedbynormalplantoperationaswellasthoseforcesgeneratedduringaseismicevent.Exceptfortheremovalofcertainstoragecellblockingdevices,theproposedlicenseamendmentdoesnotinvolveanychangetotheexistingstorageracks.Theanalysessupporting St.LucieUnit2DocketNo.50-389ProposedLicenseAmendmentL-97-325Attachment1Page.19of29theuseofthesestorageracksatUnit2weredevelopedaspartofapoolrerackinglicenseamendmentsubmittedtotheNRCin1984(Reference4);theirvaliditywasindependentlyconfirmedbytheNRC(Reference5).Theseanalyseshavebeenexaminedtodetermineifthe'changeinstoragecapacityproposedherewouldadverselyimpacttheirconclusionsorresultinanunanalyzedcondition.Thecalculationalreviewisformallydocumentedinthe"QAReviewofSt.LucieUnit2SpentFuelPoolCapacityIncrease,"ABBCombustionEngineeringNuclearOperationsDesignAnalysisNumber:A-SL2-FE-0064,Rev.02,6/12/95,andisavailablefromtheplantrecords.The1984analysesconsideredpartialloadingsofthespentfuelrackconsistentwiththepresentRegionIandRegionIIstorageconfigurations.TheseanalysesalsoconsideredthecompleteloadingofallstoragelocationswithinthefuelrackswithoutregardtotheRegionIorRegionIIstoragelimitations.The1984analysesutilizeda"consolidated"fuelweight(approximatelyequaltotwicetheweightofasinglefuelassembly)ineachstorageracklocationtoconservativelyestimatetheresultingloadsonthespentfuelrackstructureandthefuelpoolfloor.Therefore,theassumedweightperstoragecelllocation,andtheresultingstructuralandseismicanalysesofrecordareconservativec'omparedtotheresultsthatwouldbeobtainedforasinglefuelassembly.AsdiscussedinSection3.1.5ofthis'evaluation,aconservativecalculationofthemaximumfuelpooltemperatureresultingfromacompleteoff-loadingofthereactorcoreproducedawatertemperature(T.)ofapproximately155'Fwithtwocoolingpumpsinoperation.Section4.4ofReference4definesT.asthehighesttemperatureassociatedwiththepostulatedabnormaldesignconditions.ThisnewlycalculatedvalueofT.isgreaterthanthe150'FvalueforT.usedinthe1984seismicanalysis.Theimpactofthis5'FtemperatureincreaseonstoragerackstresseswasexaminedusingSectionIIIofthe'f983ASMEcode.Toensureboundingresults,rackstresseswereevaluatedassumingafuelpooltemperatureof300'F.TheresultsofthisevaluationaregiveninTable1ofthisevaluation.Theseresultsshowthatfortheplatesandsupportbarsthatcomprisethespentfuelpoolracks,stressintensitiesarelessthanallowablevaluesforbothnormalandfaultedconditionsat300'F.TheevaluationofahigherT.valuewasperformedtoensureacceptablerackstressesunderworstconditions.However,asnotedpreviouslyactualfuelpooltemperaturesduringcoreoffloadevolutionswillbelimitedtoamaximumof150'F;thereforethepreviousanalysisofrecordfortheracksandthefuelpoolstructureremainsbounding.

St.LucieUnit2DocketNo.50-389ProposedLicenseAmendmentL-97-325Attachment1Page20of29TheresultsofthisreviewdemonstratethattheSt.LucieUnit2spentfuelracksandfuelpoolfloorarequalifiedfortheincreasedstoragecapacityproposedinthislicenseamendment.6.0AsdiscussedinSections4.5and4.6,therevisedfuelpoolcriticalityanalysiscreditsthepresenceof520ppmsolubleborontoensurethatk,<<forthenewstorageconfigurationremains~0.95includingtheeffectsofuncertainties,biasesandreactivityequivalencing.Becausecreditforfuelpoolsolubleboronisassumed,itisnecessarytoidentifytheplantsystemsinterfacingwiththespentfuelpoolthatcould,throughamalfunctionor.operatorerror,crediblyinitiateadilutionevent.Thisdilutionanalysishasbeenperformedtoensurethatsufficienttimeremainsavailabletodetectandmitigateadilutioneventbeforethespentfuelpoolcriticalityanalysisdesignbasisvalueofk.<<~0.95isviolated.Enclosure2tothisevaluationcontainsadditionaldetailsontheevaluationoftheseinterfacingsystems,includingaquantificationofthetimerequiredforthelossofreactivitymargintok,<<--0.95.6.1DESCRIPTIONOFMETHODOLOGYTheborondilutionanalysisperformedforSt.LucieUnit2includesanevaluationofthefollowingplant-specificfeatures:DilutionSourcesBorationSourcesFuelPoolInstrumentationFuelPoolRelatedPlantProcedures

St.LucieUnit2DocketNo:50-389ProposedLicenseAmendmentL-97-325Attachment1Page21of29PipingImpactofaLossofOffsitePowerBoronDilutionInitiatingEventsBoronDilutionTimesandVolumesBasedonareviewofthesystemsthatinterfacewiththespentfuelpool,eachpotentialdilutionpathwasidentified.Next,theactivitiesrequiredtochangeeachpotentialdilutionpathintoanactualfuelpooldilutionpathweredetermined;thisdeterminationincludedidentifyingtheplantprocedure(s)thatcontrolledeachevolution.Thequantityofmakeupavailabletothefuelpoolthrougheachdilutionpathwaywasdeterminedandcomparedtothequantityofunboratedwaterrequiredto'dilutethefuelpooltoak,<<--0.95.Anupperboundflowratethrougheachdilutionpathwaywasdetermined.Availablesourcesofboratedmakeuptothefuelpoolwerealsoidentified.Foreachdilutionpath,thetimerequiredtoreachthefuelpooldesignvalueofk,<<wascomparedtothefrequencyoffuelpoolboronsamplingandthefrequencyofoperatorroundsinthevicinityofthespentfuelpool.Anylocalorcontrol'roomindicationsthataninadvertentdilutionmightbeinprogresswerealsoidentified.Theeffectofapotentiallossofoffsitepoweronfuelpooldilutionandborationpathwayswasidentified.6.2BORONDILUTIONINITIATINGEVENTSTheinitialscreeningoffuelpooldilutionpathwaysidentifiedsixpotentialdilutionscenariosrequiringadditionalreview.Theseare:PrimaryWaterSystemmakeupthroughvalveV-15322PrimaryWaterSystemmakeupthroughvalveV-15538PrimaryWateradditionthroughresinflushline St.LucieUnit2DocketNo.50-389ProposedLicenseAmendmentL-97-325Attachment1Page22of29PrimaryWateradditionthroughlocalfirehosestationPrecipitationeventthroughopenFHBL-shapedDoorDilutionsresultingfromSeismiceventsorrandompipebreaksSubsequently,FPLevaluatedeachofthepotentialeventinitiatorsingreaterdetailtodeterminewhethereachinitiatorposedacrediblechallengetofuelpooldesignreactivitymargin.6.3RESULTSOFINITIATINGEVENTSFollowingadetailedreviewtwopotentialdilutionpathshadcharacteristicsthatwarrantedconsiderationasapotentialchallengetofuelpoolreactivitymargins.Forthesepathways,thetimerequiredtoachieveadilutionsuchthatk,<<=0.95wasquantified.Onepathwayexaminedwastheprocedurally-specifiedmakeupflowpaththroughvalveV-15538.AssuminganinitialfuelpoolboronconcentrationequaltotheTechnicalSpecificationlimitof1720ppm,morethan79hourswouldberequiredtodilutethepooltoak,<<of0.95usingthisflowpath.Assuminganinadvertentdilutionofthefuelpoolthroughtheresinflushline,approximately60hoursisrequiredtoreducethepoolboronconcentrationfromaninitialvalueof1720ppmtoavaluesuchthatfuelpoolk.<<--0.95.AsdiscussedinEnclosure2,thisquantityofmakeup,throughanyflowpathwithoutacoincidentletdownflow,wouldresultintheoverflowofthefuelpool.Thisoverflowontothefuelpooloperatingdeckwouldbereadilyobservedbyoperationspersonnelduringtheiron-shiftrounds;atleastsevensetsofoperatorroundswouldbemadeduringthetimethisdilutionwasinprogress.6.4SPENTFUELPOOLDILUTIONEVENTCONCLUSIONSTheborondilutionanalysisoftheSt.LucieUnit2spentfuelpooldiscussedinEnclosure2ofthisevaluationhasconcludedthatanunplannedorinadvertentdilutionofthefuelpoolboronconcentrationfrom1720ppmtoconditionssuch St.LucieUnit2DocketNo.50-389ProposedLicenseAmendmentL-97-325Attachment1Page23of29thatk,<<=0.95isnotacredibleevent.Thisconclusionisbasedonthefollowing:'Morethan358,900gallonsofunboratedwaterisrequiredtodilutetheUnit2spentfuelpooltothedesignk,<<valueof0.95.Toactuallyachievethisdilution,'lantpersonnelwouldberequiredtotakecontinued,manualactionstoassurethisquantityofwaterwouldbedeliveredtothespentfuelpool.2.Thenormalmakeuppathtothespentfuelpoolfromtheprimarywatersystem(V-15538)ismaintainedlockedclosed.Thealternateprimarywatermakeuppathiscapped.3.In-placeadministrativecontrolsontheprimaryletdownpathfromthespentfuelpool(thereturnlinetotheRWT)ensurethatanyprolonged,inadvertentfuelpoolmakeupwouldresultinpooloverflow.4.Thelargevolumeofwaterrequiredtoachievethisdilutionwouldbereadilydetectedbyplantpersonnelthroughinstalledalarms,overflowofthespentfuelpoolandfloodinginthefuelhandlingbuilding,orbyoperationspersonnelontheirnormalroundsonthespentfuelpooloperatingdeckandelsewhereintheplant.5.Availableflowratestodeliverunboratedwatertothespentfuelpoolensurethatsufficienttimeisavailableforoperationspersonneltodetectandrespondtoanydilutionevent.7.0FPLhasreviewedtheenvironmentalimpactsoftheproposedlicenseamendment.Thisreview'demonstratesthattheoverallradiologicalandnonradiologicalimpactsoftheproposalareinsignificant.Thereviewissummarizedbelow.7.1THERMALIMPACTThethermalanalysisoftheeffectoftheproposedchangeonthespentfuelpoolcoolingsystemispresentedinSection3.1.5ofthisevaluation.Thatanalysisincludedadeterminationofthemaximumspentfueldecayheatloadfollowingapartialcoreoffloadandafullcoreoffload.Theproposedincrease St.LucleUnit2DocketNo.50-389ProposedLicenseAmendmentL-97-325Attachment1Page24of29instoragecapacitywillchangethemaximumdecayheatloadforapartialcoreoffloadfrom16.9E6Btu/hrto19.76E6Btu/hrandforfullcoreoffloadconditionsfrom31.7E6Btu/hrto35.22E6Btu/hr.Thisincreasedheatloa'dresultsinanincreaseofapproximately3'Finthemaximumfuelpoolwatertemperatureforthepartialcoreoffloadcase,andanincreaseofapproximately5'Finwatertemperatureforstorageofthelimitingfullcoreoffload(note:maximumfuelpooltemperaturewillbemaintaineds150'F).Becausetheevaporationratefromthepoolisassumedtobezero,theincreaseddecayheatloadisalsotheincreasedloadonthecoolingsystemandtheincreasedheatrejectedtotheenvironment.ThetotalheatloadrejectedtotheenvironmentbySt.LucieUnit2isabout6.2E9Btu/hr.Thepercentageincreaseintheheatrejectedtotheenvironmentduetotheincreaseinspentfuelstoragecapacityisontheorderof0.05%forpartialcoredischargesand0.06%forfuelstoragefollowingafullcoreoffload.07.2RADIOLOGICALEVALUATION7.2.1TheneteffectofincreasingtheSt.LucieUnit2spentfuelpoolstoragecapacityisthatolderfuelelementswillberetainedinwetstoragebeyondthetimewhentheywouldhaveotherwisebeenloadedintocasksfordrystorageon-site.Theconcentrationofradionuclidesinthespentfuelpooliscontrolledbytheactionsofthefuelpoolpurificationsystemandbythedecayofshort-livedradioactiveisotopes.Mostofthecontaminationcollectedbythefuelpoolpurificationsystemoriginateseitherfromdischargedfuelfreshlyemplacedinthefuelpoolorfromtheintermixingofspentfuelpoolwaterwithprimarywaterduringrefuelingevolutions.Retainingalready-agedfuelinwetstorageforanextendedperiodwillnotappreciablyincreasetheactivityinthefuelpoolwaterortheamountofsolidradioactivewastewhichmustbedisposedofbecausetheshort-livedisotopesassociatedwiththesefuelbundleswillhavehadanopportunity,todecay.Therefore,increasingthefuelpoolstoragecapacityasproposedforSt.LucieUnit2willhavenosignificanteffectonthequantityofradioactivewastecollected.7.2.2Storageofadditionalquantitiesoflongdecayeddischargedfuelinthespentfuelpoolwillnotsignificantlyincreasethereleaseofgaseousfissionproducts

St.LucieUnit2DocketNo.50-389ProposedLicenseAmendmentL-97-325Attachment1Page25of29suchasKr".FuelrodintegrityatSt.LucieUnit2hasbeenverygood,withmostfuelcyclesevidencingnoleakingfuelrods.Additionally,therodpressurewhichtendstoactasdrivingforceforfissionproductrelease,issubstantiallydecreasedafterlongperiodsoffuelcooling.7.2.3Theproposedlicenseamendmentdoesnotinvolveanychangestothemethodofoperatingorrangeofmotionofthespentfuelcaskhandlingcrane.Nomovementofloadsinexcessofthenominalweightofafuelassembly,CEAandassociatedhandlingtoolispermittedoverotherfuelassembliesinthestoragepool.ProtectionagainstdroppingthespentfuelcaskintothespentfuelstoragepoolisprovidedbythebasiclayoutoftheFuelHandlingBuilding.AsnotedinUFSARSection9.1.4.3.2,additionalprotectionisaffordedbythetrolleybumpersandasetoflimitswitcheswhichworktogetherwithbridgeandtrolleybrakestopreventmovementofthecranehookintotherestrictedarea.Theproposedamendmentwillalsonotinvolveanychangesinthemodeofoperatingorrangeofmotionofthespentfuelhandlingmachine.Changesinfuelassemblyweightduetotheuseofvalue-addedfuelhavebeenevaluatedanddeterminedtobeacceptable(Reference8).AsnotedinReference11,duringmovementofafuelassembly,theloadonthehoistcableismonitoredtoensurethatmovementisnotrestricted.Installedinterlockswillcontinuetorestrictmovementofthehandlingmachinewhenthehoistiswithdrawingorinsertinganassembly.TheexistinganalysesofrecordpertainingtotheradiologicalconsequencesofafuelhandlingaccidentwithintheFuelHandlingBuilding(FHB)andthepostulateddropofaspentfuelcaskjustoutsidetheFHBhavebeenexaminedtoassesstheimpactoftheproposedlicenseamendment,includingtheuseofthevalue-addedfuelpelletdesign.Thereviewisformallydocumentedinthe"QAReviewofSt.LucieUnit2SpentFuelPoolCapacityIncrease,"ABBCombustionEngineeringNuclearOperationsDesignAnalysisNumber:A-SL2-FE-0064,Rev.02,6/12/95,andinReference10,bothofwhichareavailablefromFPLNuclearEngineeringrecords.TheassumptionsandparameterspreviouslyemployedinevaluatingthefuelmishandlingaccidentwereconsistentwithRegulatoryGuides1.13and1,25.Thepreviouslyanalyzedconsequencesofdroppingaspentfuelcaskwere St.LucieUnit2DocketNo.50-389ProposedLicenseAmendmentL-97-325Attachment1Page26of29basedontheguidelinesprovidedinSection15.7.5oftheStandardReviewPlan.BasedontheresultsoftwoORIGEN-IIassemblydepletions,FPLhasconcludedthatthegapactivitiesresultingfromtheuseofvalue-addedfuelareessentiallyidenticaltothoseresultingfromtheuseofthestandardpelletdesign.FPL'sreviewoftheexistinganalysisofthefuelhandlingaccidenthasconcludedthatthegapactivitiesprovidedintheanalysisofrecordforthefuelhandlingaccidentconservativelyboundthosevaluesexpectedtooccuratassemblydischargeburnupsofupto60,000MWD/MTU(Reference1).AsdefinedbySection15.7.4oftheStandardReviewPlan,calculateddosevaluesarewellwithintheguidelinesifthecalculatedwholebodydoseiss6remandthe,calculatedthyroiddoseiss75rem.AsindicatedinTable5-9ofReference4,theseguidelinedosevalueswereeasilyachieved.FPLhasalsoexaminedtheexistinganalysisofanaccidentinvolvingthedropofaspentfuelcaskcontaining10irradiatedfuelassemblies.ThisreviewhasdeterminedthatconservativeinputassumptionswereusedandthattheresultsoftheexistinganalysisasshowninTable5-6ofReference4arewellwithintheacceptancecriteriaforaLimitingFault-2event.IncreasingthestoragecapacityoftheSt.LucieUnit2spentfuelpoolasdescribedinthisproposedlicenseamendmentwillhavenoeffectontheradiologicalconsequencesofanassumedfuelmishandlingeventorontheconsequencesofthedropofaloadedspentfuelcask.Foreachoftheseevents,thecalculateddosesaresmallrelativetotheguidelinevalues.8.0TheimpactoftheproposedincreaseinSt.LucieUnit2spentfuelstoragecapacityandtheimplicationsoftheuseofreactivitycreditforfuelpoolsolubleboronhavebeenexaminedintheabovediscussion.Eachoftheimpactsoftheproposedchangehasbeenquantifiedanddeterminedtobewithinacceptablelimitsbycomparisontoestablishedacceptancecriteria.Basedonthisexamination,FPLhasdeterminedthattheproposedchangestoSt.LucieUnit2TechnicalSpecificationsdonotconstituteasignificanthazardsdetermination(seeAttachment2).

~i St.LucieUnit2DocketNo.50-389ProposedLicenseAmendmentL-97-325Attachment1Page27of299.0SafetyEvaluationbytheOfficeofNuclearReactorRegulation,FacilityOperatingLicenseNo.NPF-16;Amendment21,May29,1987.2.SafetyEvaluationbytheOfficeofNuclearReactorRegulationRelatingtoTopicalC-8-03.WCAP-14416-NP-A;EastinghnusWNlethndnlngy,Revision1,WestinghouseElectricCorporation,November1996.4.FPLletterL-84-47(andattachments),J.W.Williams,Jr.toDarrellG.Eisenhut,St.LucieUnitNo.2DocketNo.50-389,Pra885.6.C.3--30.~Analysis,FloridaPowerandUghtCompany,St.LuciaGeneratingStationUnit2,preparedby,FranklinResearchCenter,September19,1984.ABBCENOComputerProgram,SFPOOLVersion1,VerificationandValidationReportNo.00000-AS95-CC-010,Rev.00,June1,1995.(ABB-CombustionEngineeringNuclearOperations)7.369-373.8.ii0.~'gal:hanges.(AvailablefromFPLNuclearEngineeringRecords)9.St.LucieUnit2UpdatedFSAR,throughAmendment10.10.ABB-CEletterF2-97-149,R.J.'LandtoR.J.Rodriguez(FPL),DisOctober15,1997.(AvailablefromFPLNuclearEngineeringrecords)012.SafetyEvaluationPSL-ENG-SENS-97-006,Revision1,'f'JEJnads,4-4-97.(AvailablefromFPLNuclearEngineeringrecords)

St.LucieUnit2DocketNo.50-389ProposedLicenseAmendmentSEP~IMag~pacit~olubleJ3oraxxCxedif.L-97-325Attachment1Page28of29SummaryofSt.LucieUnit2CalculatedFuelStorageRackStressIntensitiesA.CamNormalOperationFaultedOperationConditionPmPm+PbPm+Pb+PeStressIntensity(si)19,71329.67049,414AllowableStress'si)20,00030,00060,000StressIntensity(si)28.05633,262N/AAllowableStress'si)30,00045,000N/AAllowableStressbasedonatemperatureof300'F.NotethatallowablestressintensitySmis20,000psiatboth200'Fand300'F.B.Comsembly.'onJIL1983)At300'FSyoryieldstrength=22,500psi.Theallowablestressfornormaloperationis13,500psi(0.6Sy);thisislessthantheallowablestressforthefaultedcondition(1.2"Sy).Thefaultedconditionstresshasbeencalculatedtobe4965psi.Therefore,thespentfuelrackswillmeetallowablestresseswithSFPwatertemperaturesof300'F.

St.LucieUnit2DocketNo.50-389ProposedLicenseAmendmentSF~~~apacitySatubleJ3ararxCreditL-97-325AttachmenttPage29of29Xab~St.IucieUnit2EstimatedSpentFuelPoolCapacityRequirementsCycleffApproximateCycleStartupDate1/5/96TotalNumberofAssembliesinPoolfromallPreviousCycles628SpacesRequirodforFullCoreReserve217TotalNumberofSpacesNeededDuringthisCycle845ExcessStoragoAvailableExisting'ewCaeci'tCaoaci231N/A105/26/97692217909167NIA12/19/9876421798195379125/27/008362171053233071312/19/0190821711250235145/27/03980217119701631512/19/0410522171269091165/27/0611242171341191712/19/0711962171413'icensedCapacity=1076assemblies'roposedLicensedCapacity=1360assemblies

St.LucieUnit2DocketNo.50-389ProposedLicenseAmendmentSEEZMMDETERMINATIONOFNOSIGNIFICANTHAZARDSCONSIDERATIONAdaptedfromFPLNuclearEngineeringSafetyEvaluationPSL-ENG-SENS-97-083,Revision0,12/17/97.

St.LucieUnit2DocketNo.50-389ProposedLicenseAmendmentL-97-325Attachment2Page1of7DETERMINATIONOFNOSIGNIFICANTHAZARDSCONSIDERATIONDescriptionofamendmentrequest:TheamendmentwillamendTechnicalSpecification5.6.1andassociatedFigure5.6-1,andSpecification5.6.3,topermitanincreaseintheallowedSpentFuelPool(SFP)storagecapacity.Theanalysessupportingthisrequest,inpart,assumecreditforupto1266ppmboronconcentrationexistingintheSFP.Pursuantto10CFR50.92,adetermjnationmaybemadethataproposedlicenseamendmentinvolvesnosignificanthazardsconsiderationifoperationofthefacilityinaccordancewiththeproposedamendmentwouldnot:(1)involveasignificantincreaseintheprobabilityorconsequencesofanaccidentpreviouslyevaluated;or(2)createthepossibilityofanewordifferentkindofaccidentfromanyaccidentpreviouslyevaluated;or(3)involveasignificantreductioninamarginofsafety.FPLhasdeterminedthattheactivitiesassociatedwiththisproposedlicenseamendmentdonotmeetanyofthesignificanthazardsconsiderationstandardsof10CFR50.92(c)and,thereforeanosignificanthazardsconsiderationfindingisjustified.Insupportofthisdetermination,thefollowingbackgroundinformationisprovided,followedbyadiscussionofeachofthesignificanthazardsconsiderationstandardspresentedabove.St.LucieUnit2hasasinglespentfuelpoolwithatotalof1584storagecelllocationsin2distinctfuelpoolstoragerackregions.RegionIoftheUnit2spentfuelpoolstoragerackscontains448storagecellsonan8.965inchpitch.Presently,50%(or224)ofthesestoragecellsareavailabletostorefuelwithaninitialenrichmentof4.5%U"'rless;theremainingvacantstoragecellsareusedasfluxtrapstocontrolreactivity.RegionIIofthespentfuelpoolstoragerackscontains1136storagecellsonan8.965inchpitchofwhich75%(or852)arecurrentlyusable.AsofMay,1997,fivepermanentlydischargedassembliesarestoredinRegionI;687dischargedfuelbundlesarestoredinRegionII.WiththepresentlimitationsonstoragecapacityintheUnit2spentfuelpoolandtheexistinginventoryofdischargedassembliesawaitingshipmentoffsitetoaDepartmentofEnergy(DOE)facility,St.LucieUnit2willlosetheabilitytofullyoffloadthereactorcoretothefuelpoolinyear2001;itwilllosetheabilitytodischargeanyspentfuelatallinapproximately2007.Therefore,toensurethatsufficientstoragecapacitycontinuestoexistfordischargedfuel,FPLhasperformedanalysesto St.Lucie.Unit2DocketNo.50-389ProposedLicenseAmendmentL-97-325Attachment2Page2of7supportanincreaseintheutilizationoftheexistingspentfuelstorageracksatSt.LucieUnit2.Thesenewanalysessupportthestorageofupto1360fuelassembliesinthespentfuelpool,includingthepresenceof217assembliesresultingfromacompleteoffloadoftheSt.LucieUnit2reactorcore.Theadditionalstoragecellsmadeavailablebythisproposedlicenseamendmentwillpermita6yeardeferralintheneedforon-sitedrystorageofdischargedfuelatSt.Lucie.Deferringtherequirementforon-sitedrystorageatSt.LucieUnit2allowsadditionaltimeforthefullcommercializationofmulti-purposecanister(MPC)technologypriortotheselectionofaspecificcasksystem.Withthislicenseamendmentrequest,FPLproposestomodifytherequirementsofSections5.6.1and5.6.3oftheSt.LucieUnit2TechnicalSpecificationDesignEeaturestodescribetherevisedfuelstorageconfigurationinthespentfuelpoolandtoreflectthemaximumstoragecapacityoftherevisedconfiguration.Thefollowingevaluationdemonstratesthattheproposedlicenseamendmentinvolvesnosignificanthazardsconsiderations.Referenceismadetothediscussioncontainedintheattachedsafetyevaluation.Analysestosupporttheproposedfuelpool*capacityincreasehavebeendevelopedusingconservativemethodology.'heanalysisofthepotentialaccidentssummarizedbelowhasshownthatthereisnosignificantincreaseintheconsequencesofanyaccidentpreviouslyanalyzed.Areviewofrelevantplantoperationshasalsodemonstratedthatthereisnosignificantincreaseintheprobabilityofoccurrenceofanyaccidentpreviouslyanalyzed.Thisconclusionisalsodiscussedbelow.Previouslyevaluatedaccidentsthatwere'examinedforthisproposedlicenseamendmentinclude:FuelHandlingAccident,SpentFuelCaskDropAccident,andLossofallFuelPoolCooling.Therewillbenochangeinthemodeofplantoperationorintheavailabilityofplantsystemsasaresultofthisproposedchange;thesystemsinterfacingwiththespentfuelpoolhavepreviouslyencounteredboratedpoolwaterand,aredesignedtointeract St.LucieUnit2DocketNo.50-389ProposedLicenseAmendmentL-97-325Attachment2Page3of7withirradiatedspentfuelandremovetheresidualheatloadgeneratedbyisotopicdecay.Theproposedamendmentdoesnotrequireachangeinthemaintenanceintervalormaintenancescopeforthefuelpoolcoolingsystemorforthespentfuelcaskcrane.Thefrequencyofcaskhandlingoperationsandthemaximumweightcarriedbythecraneisnotincreasedasaresultoftheproposedlicenseamendment.Thus,therewillbenoincreaseintheprobabilityofalossoffuelpoolcoolingorintheprobabilityofafailureofthecaskcraneasaresultoftheproposedamendment.Therewillnotbeasignificantincreaseinthefrequencyofhandlingdischargedassembliesinthefuelpoolasaresultofthischange;anyhandlingoffuelinthespentfuelpoolwillcontinuetobeperformedinboratedwater..lfthelicenseamendmentisapproved,therewillbeaone-time.repositioningofcertaindischargedassembliesstoredinthefuelpooltocomplywiththerevisedpositioningrequirements,buttheincreasedpoolstoragecapacitywillpermitthedeferralof'spentfuelhandlingassociatedwithcaskloadingoperations.Fuelmanipulationduringtherepositioningactivitywillbeperformedinthesamemannerasforfuelplacedinthespentfuelpoolduringrefuelingoutages.Therewillbenochangesinthemannerofhandlingfueldischargedfromthecoreasaresultofrefueling;administrativecontrolswillcontinue.tobeusedtospecifyfuelassemblyplacementrequirements.TherelativepositionsofRegionIandRegionIlstoragelocationswillremainthesamewithinthefuelpool.Therefore,theprobabilityofafuelhandlingaccidenthasnotbeensignificantlyincreased.Theconsequencesofafuelhandlingaccidenthavebeenevaluated.Theradioactivereleaseconsequencesofadroppedfuelassemblyarenotaffectedbytheproposedincreaseinfuelpoolstoragecapacity.TheyremainboundedbytheresultsofcalculationsperformedtojustifytheexistingSt.LucieUnit2fuelstorageracksandburnuplimits.Atthelimitingfuelassemblyburnup,radioactivereleasesfroma.droppedassemblywouldbeonlyasmallfractionofNRCguidelines.Theinputparametersemployedinanalyzingthiseventareconsistentwiththecurrentvaluesoffuelenrichment,dischargeburnupanduraniumcontentusedatSt.LucieUnit2andwithfutureuseofthe"value-added"fuelpelletdesign.Thus,theconsequencesofthefuelassemblydropaccidentwouldnotbesignificantlyincreasedfromthosepreviouslyevaluated.Thecapabilityofthefuelpoolcoolingsystemtohandletheincreasednumberofdischargedassemblieshasbeenexamined.Theimpactofatotallossofspentfuelpoolcoolingflowonavailableequipmentrecoverytimeandonfuelcladdingintegrityhasalsobeenevaluated.Forthelimitingfullcoredischarge,sufficienttimeremainsavailabletorestorecoolingflowortoprovideanalternatemakeupsourcebefore St.LucieUnit2DocketNo.50-389.ProposedLicenseAmendmentL-97-325Attachment2Page4of7boiloffresultsinafuelpoolwaterlevellessthanthatneededtomaintainacceptableradiationdoselevels..Analysishasshownthatintheeventofatotallossoffuelpoolcoolingfuelcladdingintegrityismaintained.Therefore,theconsequencesofalossoffuelpoolcoolingevent,includingtheeffectoftheproposedincreaseinfuelpoolstoragecapacity,havenotbeensignificantlyincreasedfrompreviouslyanalyzedresultsforthistypeofaccident.TheanalysisofrecordpertainingtotheradiologicalconsequencesofthehypotheticaldropofaloadedspentfuelcaskjustoutsidetheFuelHandlingBuildingwasexaminedtodeterminetheimpactoftheincreasedfuelstoragecapacityonthisaccident'sresults.Theresultsofthepreviouslyperformedanalysisweredeterminedtoboundtheconditionsdescribedbytheproposedlicenseamendment,thustheconsequencesofthecaskdropaccidentwouldnotbesignificantlyincreasedasaresult.ofthischange.ItisconcludedthattheproposedamendmenttoincreasethestoragecapacityoftheSt.LucieUnit2spentfuelpoolwillnotinvolveasignificantincreaseintheprobabilityorconsequencesofanyaccidentpreviouslyevaluated.2.InthislicenseamendmentFPLproposestocreditthenegativereactivityassociatedwithaportionofthesolubleboronpresentinthespentfuelpool.SolubleboronhasalwaysbeenpresentintheSt.LucieUnit2spentfuelpool;assuchthepossibilityofaninadvertentfuelpooldilutionhasalwaysexisted.However,thespentfuelpooldilutionanalysisdemonstratesthatadilutionoftheUnit2spentfuelpoolwhichcouldincreasethepoolk,<<togreaterthan0.95isnotacredibleevent.NeitherimplementationofcreditforthereactivityoffuelpoolsolubleboronnortheproposedincreaseinthefuelpoolstoragecapacitywillcreatethepossibilityofanewordifferenttypeofaccidentatSt.LucieUnit2,IfAnexaminationofthelimitingfuelassemblymisloadhasdeterminedthatthiswouldnotrepresentanewordifferenttypeofaccident.Noneoftheotheraccidentsexaminedasapartofthislicensesubmittalrepresentanewordifferenttypeofaccident;eachofthesesituationshasbeenpreviouslyanalyzedanddeterminedtoproduceacceptableresults.

St.LucieUnit2DocketNo.50-389ProposedLicenseAmendmentL-97-325Attachment2Page5of.7TheproposedlicenseamendmentwillnotresultinanyotherchangesinthemodeofspentfuelpooloperationatSt.LucieUnit2orinthemethodofhandlingirradiatednuclearfuel.Thespatialrelationshipbetweenthefuelstorageracksandthecaskcranerangeofmotionisnotaffectedbytheproposedchange.Asaresultoftheevaluationandsupportinganalyses,FPLhasdeterminedthattheproposedfuelpoolcapacityincreasedoesnotcreatethepossibilityofanewordifferenttypeofaccidentfromanyaccidentpreviouslyevaluated.3.Eh~ra~ately.FPLhasdetermined,basedonthenatureoftheproposedlicenseamendmentthattheissueofmarginofsafety,whenappliedtothisfuelpoolcapacityincrease,should~~~addressthefollowingareas:1.FuelPoolreactivityconsiderations2.FuelPoolborondilutionconsiderations3.Thermal-Hydraulicconsiderations4.StructuralloadingandseismicconsiderationsTheTechnicalSpecificationchangesproposedbythislicenseamendment,theproposedspentfuelpoolstorageconfigurationandtheexistingTechnicalSpecificationlimitsonfuelpoolsolubleboronconcentrationprovidesufficientsafetymargintoensurethatthearrayoffuelassembliesstoredinthespentfuelpoolwillalways'remainsubcritical.TherevisedspentfuelstorageconfigurationisbasedonaUnit2specificcriticalityanalysisperformedusingmethodologyconsistentwiththatapprovedbytheNRC.Additionally,thesolubleboronconcentrationrequiredbycurrentTechnicalSpecificationsensuresthatthefuelpoolk,<<willbealwaysbemaintainedsubstantiallylessthan0.95.TheUnit2criticalityanalysisestablishedthatthek,<<ofthespentfuelpoolstoragerackswillbe(1.0withnosolubleboroninthefuelpoolwater,includingtheeffectofalluncertaintiesandtolerances..Creditforthesolubleboronactuallypresentisusedto.offsetuncertainties,tolerances,off-normalconditionsandtoprovidemarginsuchthatthespentfuelpoolk,<<ismaintaineds0.95.FPLhasalsodemonstrated St.LucieUnit2DocketNo.50-389ProposedLicenseAmendmentL-97.-325Attachment2Page6of7thatadecreaseinthefuelpoolboronconcentrationsuchthatk,<<exceeds0.95isnotacredibleevent.CurrentTechnicalSpecificationsrequirethatthefuelpoolboronconcentrationbemaintained>1720ppm.Thisboronvalueissubstantiallyinexcessofthe520ppmrequiredbytheuncertaintyandreactivityequivalencinganalysesdiscussedinthisevaluationandthe1266ppmvaluerequiredtomaintaink,<<<0.95inthepresenceofthemostadversemispositionedfuelassembly.TheSt.LucieUnit2fuelpoolboronconcentrationwillcontinuetobemaintainedsignificantlyinexcessof1266ppm;theproposedlicenseamendmentwillnotresultinchangesinthemodeofoperationoftherefuelingwatertank(RWT)orinitsuseformakeuptothefuelpool.Thus,operationofthespentfuelpoolfollowingtheproposedchange,combinedwiththeexistingfuelpoolboronconcentrationTechnicalSpecificationlimitof1720ppm,willcontinuetoensurethatk,<<of.thefuelpoolwillbesubstantiallylessthan0.95.Evenifthisnot-credibledilutioneventwastooccur,noradiationwouldbereleased;theonlyconsequencewouldbeareductionofshutdownmargininthefuelpool.Thevolume'ofunboratedwaterrequiredtodilutethefuelpooltoak,<<of0.95issolarge(inexcessof358,9GGgallonstodilutethefuelpoolto520ppmboron)thatonlyalimitednumberofwatersourcescouldbeconsideredpotentialdilutionsources.Thelikelihoodthatthislevelofwaterusecouldremainundetectedbyplantpersonnelisextremelyremote.Inmeetingtheacceptancecriteriaforfuelpoolreactivity,theproposedamendmenttoincreasethestoragecapacityoftheexistingfuelpoolracksdoesnotinvolveasignificantreductioninthemarginofsafetyfornuclearcriticality.CalculationsofthespentfuelpoolheatloadwithanincreasedfuelpoolinventorywereperformedusingANSI/ANS-5.1-1979methodology.ThismethodwasdemonstratedtoproduceconservativeresultsthroughbenchmarkingtoactualSt.LucieUnit2fuelpoolconditionsandbycomparisonofitsresultstothosegeneratedbyacalculationusingAuxiliarySystemsBranchTechnicalPosition9-2methodology.Conservativemethodswerealsousedtodemonstratefuelcladdingintegrityismaintainedintheabsenceofcoolingsystemforcedflow.Theresultsofthesecalculationsdemonstratethat,forthelimitingcase,theexistingfuelpoolcoolingsystemca'nmaintainfuelpoolconditionswithinacceptablelimitswiththeincreasedinventoryofdischargedassemblies.Therefore,theproposedchangedoesnotresult St.LucieUnit2DocketNo.50-389ProposedLicenseAmendmentL-97-325Attachment2Page7of7inasignificantreductioninthemarginofsafetywithrespecttothermal-hydraulicorspentfuelcoolingconsiderations.Theprimarysafetyfunctionofthespentfuelpoolandthefuelstorageracksistomaintaindischargedfuelassembliesinasafeconfigurationforallenvironmentsandabnormalloadings,suchasanearthquake,alossofpoolcoolingoradropofaspentfuelassemblyduringroutinespentfuelhandling.Theproposedincreaseinspentfuelinventoryonthefuelpoolandtheexistingstoragerackshavebeenevaluatedandshowthatrelevantcriteriaforfuelrackstressesandfloorloadingshavebeenmetandthattherehasbeennosignificantreductioninthemarginofsafetyforthesecriteria.To'summarize,ithasbeenshownthattheproposedincreaseincapacityoftheexistingSt.LucieUnit2spentfuelpoolstorageracksandtheproposedTechnicalSpecificationchangesdonot:1.Involveasignificantincreaseintheprobabilityorconsequencesofanaccidentpreviouslyevaluated;or2.Createthepossibilityofanewordifferentkindofaccidentfromanyaccidentpreviouslyevaluated;or3.Involveasignificantreductioninamarginofsafety.Therefore,FPLhasdeterminedthattheproposedlicenseamendmentinvolvesnosignificanthazardsconsiderations.