ML17228B502

Application for Exigent Amend to License DPR-67,revising TS Re Thermal Margin & RCS Flow Limits.Siemens Power Corp Rept EMF-96-135, St Lucie Unit 1 Chapter 15 Event Review & Analysis for 30% SG Tube Plugging Encl

ML17228B502
Person / Time
Site:	Saint Lucie
Issue date:	06/01/1996
From:	BOHLKE W H FLORIDA POWER & LIGHT CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML17228B503	List: ML17228B502 ML17228B504 ML17228B505
References
L-96-141, NUDOCS 9606030191
Download: ML17228B502 (32)

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DOCKET05000335NOTES:CATEGORY1,REGULPT%INFORMATIONDZSTRIBUTIOlZSTEM(RIDE)IACCESSIONNBR:9606030191DOC.DATE:96/06/01NOTARIZED:YESFACIL:50-335St.LuciePlant,Unit1,FloridaPower6LightCo.AUTH.NAMEAUTHORAFFILIATIONBOHLKEFW.H.FloridaPower&LightCo.RECIP.NAMERECIPIENTAFFILIATION5~DocumentControlBranch(DocumentControlDesk)p~

SUBJECT:

ApplicationforexigentamendtolicenseDPR-67,revisingTS~pge.PrrethermalmarginaRCSflowlimits.SiemensPowerCorpReptEMF-96-135,"StLucieUnit1Chapter15EventRview6Analysisfor30%SGTubePlugging"encl.DISTRIBUTIONCODE:AOOZDCOPIESRECEIVED:LTRlENCLjSIZE:ZkTITLE:ORSubmittal:GeneralDistributionERECIPIENTIDCODE/NAMEPD2-3LAWIENS,L.INTERNAL:ACRSNRR/DE/EMCBNRR/DSSA/SPLBNUDOCS-ABSTRACTEXTERNAL:NOACCOPIESLTTRENCL1~1111111111111RECIPIENTIDCODE/NAMEPD2-3PDNRR/DRCH/HICBNRR/DSSA/SRXBOGC/HDS3NRCPDRCOPIESLTTRENCL1111111110110DENTNOTETOALL"RIDS"RECIPIENTS:PLEASEHELPUSTOREDUCEWASTE!CONTACTTHEDOCUMENTCONTROLDESK,ROOii!OWFN5D-5(EXT.415-2083)TOELIMINATEYOURNAMEFROMDISTRIBUTIONLISTSFORDOCUMENTSYOUDON'TNEED!TOTALNUMBEROFCOPIESREQUIRED:LTTR13ENCL12 FloridaPower5LightCompany,P.O.Box128,FortPierce,FL34954-0128June1,1996'-96-14110CFR50.9010CFR50.91U.S.NuclearRegulatoryCommissionAttn:DocumentControlDeskWashington,D.C.20555Re:St.LucieUnit1DocketNo.50-335ProposedExigentLicenseAmendmentThermalMarinandRCSFlowLimitsPursuantto10CFR50.90,FloridaPower6LightCompany(FPL)requeststoamendFacilityOperatingLicenseDPR-67forSt.LucieUnit1byincorporatingtheattachedTechnicalSpecifications(TS)revisions.Basedonsafetyanalysesassumptionsof30'average)ofallsteamgeneratortubesremovedfromservice,theamendment.reducesthestatedvalueofdesignreactorcoolantflowfrom355,000gpm'to345,000gpm,revisesthereactorcorethermalmarginsafetylimitsshowninFIGURE2.1-1,andmodifiesthereactorcoolantsystemtotalwaterandsteamvolumedescribedinthedesignfeatures.TheamendmentalsoreducestheLimitingSafetySystemSettingforthereactorcoolantlowflowtripfunctionfrom>95%to2934ofdesignreactorcoolantflow.Finally,TS2.1.1ismodifiedtolimitreactorpowerto<90'atedthermalpowerforCycle14operationexceedingmid-cyclefuelburnupconditions.Itisrequestedthattheproposedamendment,ifapproved,beissuedbyJune20,1996,tofacilitatetimelyresumptionofpoweroperations.FPLbelievesthatthepresentsituationatSt.LucieUnit1satisfiestherequisiteconditionsforissuanceofanexigentamendmentandherebyrequestsconsiderationofthissubmittalpursuantto10CFR50.91(a)(6).Attachment1providesthebasisforconsiderationoftherequest.asanexigentamendment.Attachment2isanevaluationoftheproposedTSchange.Attachment3isthe"DeterminationofNoSignificantHazardsConsideration."Attachment4containsacopyoftheappropriateTSpagesmarked-uptoshowtheproposedchanges.Enclosedwiththissubmittalisacopyof"SiemensPowerCorporation-NuclearDivision,St.LucieUnit1Chapter15EventReviewandAnalysisfor304SteamGeneratorTubePlugging,EMF-96-135;May,1996"PbOb030000gg5qbObOiPDRADQCK0PPDRanFPLGroupcompany h~

St.LucieUnit1DocketNo.50-335ProposedExigentLicenseAmendmentThermalMarinandRCSFlowLimitsL-96-141Page2TheproposedamendmenthasbeenreviewedbytheSt.LucieFacilityReviewGroupandtheFloridaPower6LightCompanyNuclearReviewBoard.Inaccordancewith10CFR50.91(b)(1),acopyoftheproposedamendmentisbeingforwardedtotheStateDesigneefortheStateofFlorida.Pleasecontactusifthereareanyquestionsaboutthissubmittal.Verytrulyyours,W.H.BohlkeVicePresidentNuclearEngineeringandLicensingWHB/RLDAttachmentsEnclosurecc:StewartD.Ebneter,Regiona'lAdministrator,RegionII,USNRC.SeniorResidentInspector,USNRC,St.LuciePlant.Mr.W.A.Passetti,FloridaDepartmentofHealthandRehabilitativeServices.

St.LucieUnit1=DocketNo.50-335ProposedEmergencyLicenseAmendmentThermalMarinandRCSFlowLimitsL-96-141Page3))COUNTYOFST.LUCIE)SS.W.H.Bohlkebeingfirstdulysworn,deposesandsays:ThatheisVicePresident,NuclearEngineeringandLicensing,fortheNuclearDivisionofFloridaPower6LightCompany,theLicenseeherein;Thathehasexecutedtheforegoingdocument;.thatthestatementsmadeinthisdocumentaretrueandcorrecttothebestofhisknowledge,informationandbelief,andthatheisauthorizedtoexecutethedocumentonbehalfofsaidLicensee.W.H.BohlkeSTATEOFFLORDACOUNTYOF,~CA~Theforegoinginstrumentwasacknowledgedbeforemethisdayof,19'7(byW.Bohlke,o'ersonallyknowntomeandwhdidtakah..+MYou)z(~NameofNotaryPublicMyCommissionexpiresRRE'ommissionNo.EALOFHCIALNOTARYSKARENEGUTOWSKINOI'ARYPUBLICSTATEOFFLORIDACOMMISSIONNO.CC387743MYCOMMISSIONEXP.LY30,1998

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~L~1St.LucieUnit1DocketNo.50-335ProposedExigentLicenseAmendmentThermalMarinandRCSFlowLimitsATTACHMENT1BASISFOREXIGENTAMENDMENTCONSIDERATION Se

~~~zSt.LucieUnit1DocketNo.50-335ProposedExigentLicenseAmendmentThermaMarinandRCSFlowLimitsL-96-141Attachment1Page1of2BASISFOREXIGENTAMENDMENTCONSIDERATIONPursuantto10CFR50.91(a)(5)and(6),theNRCmayadjudgethatanemergencyorexigentsituationexists,inthatfailureoftheNRCtoactinatimelywayonarequestforlicenseamendmentwouldresultinpreventionofresumptionofoperationofanuclearpowerplant.Forconsiderationofthisprovision,thelicenseeisrequiredtoexplainwhytheemergencyorexigentcircumstanceoccurredandwhyitcouldnotbeavoided.TheNRCwillthenassessthelicensee'sreasonsforfailingtofiletheapplicationsufficientlyinadvanceoftheevent,andifitdeterminesthatthelicenseehasnotabusedtheemergency/exigentprovision,itmayissuealicenseamendmentinvolvingnosignificanthazardsconsiderationwithoutthe30daysnormallyallowedforpriornoticeandopportunityforahearingorforpubliccomment.AdiscussionofwhythepresentsituationatSt.LucieUnit1satisfiestherequisiteconditionsforissuanceofanexigentamendmentfollows.1.WhtheExiencOccurredandCouldNotbeAvoided.OnApril29,1996,St.LucieUnit1enteredascheduledrefuelingoutage.Amarginofapproximately14%existedbetweentheaveragenumberofsteamgenerator(SG)tubesthathadbeenpreviouslyremovedfromserviceandthenumberofpluggedtubesassumedinthesafetyanalyses.Basedona10yearhistoryof1004EddyCurrentTesting(ECT),andincludingadditionalinspectioncommitmentspursuanttogenericletter(GL)95-03,"CircumferentialCrackingofSteamGeneratorTubes,"thenumberoftubesconservativelyestimatedtoberemovedfromserviceduringthisoutagewasfarlessthantheremaininganalyticalmargin.BasedonconcernsinvolvingthequalificationoftechniquesforsizingSGtubecrack-likeindicationsthatwerecommunicatedtoindustrybytheNRCstaffattheNRCRegulatoryInformationConferenceheldApril9-10,1996,FPLmadeapro-activepresentationtothestaffonApril22,1996,outliningthestatusofSGcondition,ECTtechniquequalification,andscheduledrefuelingoutageplansfortheSt.LucieUnit1SGs.InafollowuptelephoneconversationwiththestaffonMay7,1996,thestaffquestionedtherepaircriteriawhichhavebeeninplaceatFPLsince1985.FPLsubsequentlyagreedtoimplementamoreconservativecriteriafortheCycle14inspection.FPLdocumentedthiscommitmentasoutlinedinFPLletterL-96-129datedMay14,1996.Ourassessment,oftheimpactofimplementingthiscriteriaindicatesthatthenumberofSGtubestobepluggedmayexceedtheexisting254(average)analyseslimit.

St.LucieUnit1DocketNo.50-335ProposedExigentLicenseAmendmentThermalMarinandRCSFlowLimitsL-96-141Attachment1~Page2of22.BasisfortheExientAmendmentReuest.SteamgeneratortubeinspectionsatSt.LuciemeetorexceedcriteriacontainedintheSt.LucieUnit1TechnicalSpecifications,andPWRSteamGeneratorExaminationGuidelines,Revision3,EPRIReportNP-6201,November,1992.UponcompletionofreviewandevaluationofdatabyindustrygroupsandFPL,newtechnologyhasbeenroutinelyimplementedatSt.Lucieinamannertoprovidealinktopreviousexaminationdata.ThechangeinrepaircriteriaandthemagnitudeofresultantSGtubepluggingcouldnothavebeenreasonablyanticipatedpriortoNRCstaffconcernshavingbeencommunicatedtoFPLduringtherecentmeetinganddiscussions.TheneedforanamendmenttoimplementrevisedSt.LucieUnit1powerandRCSflowlimitscouldnothavebeenanticipatedpriortoassessingtheimpactofthechangeinrepaircriteriafollowingFPL'smeetinganddiscussionswiththeNRCstaff.Thenecessaryevaluationsandpreparationoftheproposedlicenseamendmentwereinitiatedwithoutdelayandattheearliestpracticaltime.Analysesandqualityassuranceverificationstosupporttheproposedlicenseamendmentwerecompletedinanexpeditiousmanner,andwereperformedinparallelwiththeongoingtubeexaminations.FPLexpectstocompletetherefuelingoverhaulandtherequiredstartuppreparationsbyJune20,1996.Untilalicenseamendmentisissuedtoauthorizeoperationwiththeproposedchanges,resumptionofSt.LucieUnit1poweroperationswillbepreventedbythecurrentTechnicalSpecifications.Basedontheprecedingdiscussions,FPLbelievesthatthepresentsituationcouldnothavebeenanticipatedtotheextentthatarequestforamendmentcouldhavebeenfiledsufficientlyinadvance;thattheemergency/exigencyprovisionhasnotbeenabusedbynotmakingatimelyapplicationandthusitselfcreatingexigentcircumstances;andthatthislicenseamendmentrequestsatisfiescriteriaforconsiderationpursuantto10CFR50.91(a)(6).

St.LucieUnit1DocketNo.'0-335ProposedExigentLicenseAmendmentThermalMarinandRCSFlowLimitsATTACHMENT2EVALUATIONOFPROPOSEDTSCHANGES St.LucieUnit1DocketNo.50-335ProposedExigentLicenseAmendmentThermalMarinandRCSFlowLimitsL-96-141Attachment2Page1of16TABLEOFCONTENTS1.Introduction2.ProposedTSChangesandBases3.GeneralEffectoftheProposedChangesonEventAnalyses4.,EvaluationofUFSARChapter15Eventsa.DecreaseinSecondarySideHeatRemovalb.DecreaseinReactorCoolantSystemFlowRatec.ReactivityandPowerDistributionAnomaliesd.DecreaseinReactorCoolantInventoryEventse.UncontrolledCEAWithdrawalf.BoronDilutionEventg.CEAEjectionAccidentsh.InadvertentOpeningofPressurizerPressureReliefValvesi.SteamGeneratorTubeRupture(SGTR)j.IncreaseinHeatRemovalbytheSecondarySystemk.ReactorProtectionSetpoints5.EvaluationofOtherSelectedUFSARAnalysesa.PlantNaturalCirculationCapabilityb.PeakContainmentPressurizationFollowingLBLOCAorSteamSystemPipingFailurec.AuxiliaryFeedwater(AFW)HighEnergyLineBreakd.LowTemperatureOverpressureProtection(LTOP)e.OverpressureProtectionAnalysisf.ImpactonSteamGeneratorMechanicalLoads6.Conclusion16 St.LucieUnit1DocketNo.50-335ProposedExigentLicenseAmendmentThermalMarinandRCSFlowLimitsL-96-141Attachment2Page2of16EVALUATIONOFPROPOSEDTSCHANGES1.,IntroductionSafetyanalysesapprovedforSt.LucieUnit1(PSL1)assumeaminimumdesignReactorCoolantSystem(RCS)flowrateof355,000gpmandanaverage25~(+7%)ofallsteamgeneratortubesplugged(SGTP).DuringtheSpring1996refuelingoverhaul,theestimatednumberofadditionalsteamgeneratortubesthatwillberemovedfromservice(currentlyinexcessof2000)willlikelyexceedthe254(average)analyseslimit.ToconservativelyaccommodatethelargernumberofpluggedSGtubes,FloridaPowerandLightCompany(FPL)proposestochangethePSL1TechnicalSpecifications(TS)toreflectsafetyanalysisassumptionsof345,000gpmminimumRCSdesignflowrate(basedon30%averageofallsteamgeneratortubesplugged),andproposesachangeintheReactorProtectiveSystemRCSLowFlowLimitingSafetySystemSettingfrom>954to>93~~ofdesignreactorcoolantflow.EvaluationstoassesstheimpactoftheproposedchangeswereperformedbyFPLandSiemens.PowerCorporation-NuclearDivision(SPC).IthasbeendeterminedthattheresultsofthecurrentSmallBreakLossofCoolantAccident(SBLOCA)analysis,whichassumes25~averageSGTP(+74)and355,000gpmreactorcoolantflow,willcontinuetoboundfullpoweroperationwiththeproposedamendmentforfuelbatchaverageburnupconditionsnotexceeding9135Mwd/MTU(7000EffectiveFullPowerHours(EFPH)inCycle14).Toassureacceptablemarginsforfullpoweroperationbeyondthispoint,theSBLOCAeventanalysismustbeperformedusingthevaluesofhigherSGTPandreducedflow.Accordingly,theproposedamendmentmodifiesTS2.1.1tolimitreactorpowerto<904ratedthermalpowerforCycle14operationbeyond7000EFPH.2.ProosedTSChanesandBasesCopiesoftheaffectedTSpages,marked-uptoshowthechanges,arecontainedinAttachment4tothissubmittal.a.Pae2-1Secification2.1.1REACTORCORE:InsertanasteriskfollowingTHERMALPOWER,andaddthefollowingfootnote:*ForCycle14operationbeyoml7000LPPH,THERMALPOWERshallnoterceed90%of2700Megawatts(thermal).

St.LucieUnit.'1DocketNo.50-335ProposedExigentLicenseAmendmentThermalMarinandRCSFlowLimitsL-96-141Attachment2Page3of16b.ThelimitonthermalpowerforCycle14operationbeyond7000EFPHassuresthatcalculatedpeakfuelcladdingtemperaturesduringSBLOCAremainwithin10CFR50.46acceptancecriteriafortheentireoperatingcycle.Pae2-2FIGURE2.1-1ReactorCoreThermalMarinSafetLimit-FourReactor.CoolinPumsOeratin:ReplacethisfigureinitsentiretywiththerevisedFIGURE2.1-1showninAttachment4ofthissubmittal.c~The"vesselflowlessmeasurementuncertainties"ischangedfrom355,000gpmto345,000gpmbasedon30~averageSGTP.ThethermallimitlinesshowninthisfigurehavebeenrevisedtoreflectthereducedflowusingSPCmethodology.Thelinesrepresentthelociofpointsofthermalpower,ReactorCoolantSystem(RCS)pressure,andmaximumcoldlegtemperaturewith.fourreactorcoolantpumpsoperatingforwhichtheDeparturefromNucleateBoilingRatio(DNBR)isnolessthantheDNBRlimitforthemostlimitingaxialpowerdistributionshowninTSFigureB2.1-1.TheminimumDNBR'limitforsteadystateoperation,normaloperationaltransients,andanticipatedtr'ansientsremainsunchangedfromtheexisting,approvedvalueof1.22.Thisvaluecorrespondsto95%probabilityata954confidencelevelthatDNBwillnotoccurandrepresentsanacceptablemargintoDNBforalloperatingconditions.Pae2-4TABLE2.2-1ReactorProtectiveInstrumentationTriSetointLimits:(1)ChangetheTRIPSETPOXNTandALLOWABLEVALUESforFUNCTIONALUNIT3,ReactorCoolantFlow-Low,from>954ofdesignreactorcoolantflowwith4pumpsoperating*to293%ofdesignreactorcoolantfio>vwith4pumpsoperating*.RCSflowisdeterminedbycalorimetricmethodsduringpowerascensiontestingafterarefuelingoutage.Theactuallowflowtripsetpointisbasedonthisinferredflowmeasurementandisprocedurallycontrolledtoconsidercalorimetricuncertainties,instrumentloopuncertainties,instrumentsignalnoise,andthespecifieddesignRCSflow.TheproposedLSSSisconsistentwithCycle14safetyanalysisassumptionsandwillprovideadditionaloperatingmargintoprotectagainstunwarranted,spuriouslowflowtripsand/orpre-tripalarms.(2)InFootnote*,changethedesignreactorcoolantflowwith4pumpsoperatingfrom355,000gpmto345,000gpm.The I~~~pSt.LucieUnit1DocketNo.50-335ProposedExigentLicenseAmendmentThermalMarinandRCSFlowLimitsL-96-141Attachment2Page4of16proposedvalueiscommensuratewiththeminimumdesignflowexpectedwith30~SGTP.Id.Pae342-14TABLE3.2-1DNBMARGIN:ChangetheReactorCoolantFlowRatefrom355,000gpmto345,000gpm.Theproposedvalueiscommensuratewiththeminimumdesignflowexpectedwith30>oSGTP~e.Pae5-5DESIGNFEATURESSecification5.4.2:Modifythedescriptionofthereactorcoolantsyst:emVOLUMEtoread:Thetotalwaterandsteamvolumeofthereactorcoolantsystemis11,100+180cubicfeetatanominalT,,of567'F,whennotaccountingforsteamgeneratortubeplugging.ThisisanadministrativechangetoclarifytheconditionforwhichthestatedvalueofRCSvolumeisapplicable.3.GeneralEffectoftheProosedChanesonEventAnalsisThechangesproposedbythislicenseamendmentcanaffecttheplantsafetyanalysesinthefollowingmanner.a.AreductioninRCSflowratehasanadverseeffectonthecalculatedDeparturefromNucleateBoilingRatio(DNBR).DNBRisadirectindicationofavailablethermalmargin,andareductioninthecalculatedminimumDNBRindicatesthatthermalmarginforthecorrespondingtransienthasbeenreduced.b.Areductioninthevalueofthelowflowtripsetpointwillresultinalowerreactorcoreflowrateatthetimeofreactortrip,andcantherebyimpactthecalculatedminimumDNBRforcertaintransients.c.AreductioninRCSflowrateresultsinacorrespondingincreaseinRCSaveragecoolanttemperature(Tave).AhigherTavecanimpactbothDNBR-relatedandlossofprimaryinventorytypesoftransients.d.Theremovalofadditionalsteamgeneratortubesfromservice(plugging)reducestheprimarytosecondaryheattransferareainthesteamgenerators.Thiseffectismostrelevanttotransientsinvolvingasuddenreductionintheheatremovalcapabilityofthesecondaryplant.Inaddition,areductionofinitialRCSinventoryduetosignificantSGTPcanaffect

~~I~St.LucieUnit1DocketNo.50-335ProposedExigentLicenseAmendmentThermalMarinandRCSFlowLimitsL-96-141Attachment2Page5of16theresultsofborondilutionevents,aswellasthedepthofcoreuncoveryandcalculatedpeakcontainmentpressureresultingfromlossofcoolantaccidents.4.EvaluationofUFSAR'hater15EventsAreviewofeventsintheSt.LucieUnit1UpdatedSafetyAnalysisReport(UFSAR)toassesstheimpactfromplantoperationwithanincreaseinaverageSGTPto30%(+74),areductioninRCSdesignflowto345,000gpm,andalowflowLSSSof93%ofdesignflowwasperformed'ybothFPLandSPC.SPC'sevaluation,includingreanalysisdata,isreportedintheEnclosure(EMF-96-135)withthissubmittal,andincludesasummarydispositionwithStandardReviewPlan/UFSAReventcross-referenceinTable3.1.DescriptionsofhowtheincreasedSGTPandreducedRCSflowhasbeenevaluatedtoimpactselectedeventsfollow.a.DecreaseinSecondarSideHeat.RemovalLossofExternalLoadLOELTheLossofExternalLoad(LOEL)wasreanalyzedtoexaminetheimpactoftheproposedchangesonthecalculatedmaximumprimaryandsecondarypressures,andtodeterminewhethertheexistingpressurelimitof2750psiafortheprimary,and1100psiaforthesecondarywouldbeexceeded.TheLOELtransientisthelimitingeventinthe"DecreaseinHeatRemovalbytheSecondarySystem"classbecauseofmostrapidreductionofsecondaryheatremovalcapabilitythroughclosureoftheturbinestopvalves.TheassumptionsusedinthisanalysisresultinthiseventbeingmoreseverethantheTurbineTrip,LossofCondenserVacuum,andMainSteamIsolationValveClosureeventsfromapressurizationviewpoint.FromDNBRconsiderations,thiseventisboundedbytheLossofFlow(LOF)transient.SinceareductionininitialRCSflowisexpectedtoimpactDNB-relatedeventsinasimilarmanner,itisconcludedthatthiseventwillcontinuetoremainboundedforDNBRbytheLossofFlowevent.ImportantassumptionsusedtomaximizeRCSpressureinthistransientare:(a)positiveModeratorTemperatureCoefficient(+7pcm/F)consistentwiththemaximumallowedbyTS3.1.1.4,(b)reducedS/Gheattransferareaconsistentwiththeproposedtubepluggingvalue,(c)inoperablesteamdumpand

~t~IIll1 St.LucieUnit1DocketNo.50-335ProposedExigentLicenseAmendmentThermalMarinandRCSFlowLimitsL-96-141Attachment2Page6of16bypasssystem,(d)transientinitiatedbyclosureoffastacting(turbinestop)valve,and(e)reactortripbyturbinetripdisabled.AreductionintheRCSflowhasnodirectimpactonthesystempressurization.AnincreasedS/Gtubeplugginghastheeffectofincreasingtheprimarycoolantinsurgeintothepressurizer.Thisisbecausethereducedprimary-to-secondaryheattransferarearesultsinalowerinitialsecondarysidepressure,thusdelayingMainSteamSafetyValve(MSSV)actuationandleadingtoagreaterexpansionoftheRCSfluid.Thiseffectwilltendtoincreaseprimarysyst:empressure.Resultsofthere-analysisforthiseventindicatethecalculatedpeakprimarypressuretobe2714psia,belowthe.limitingcriteriaof110'oofdesignpressure(2750psia).Secondarysystempressurewasdeterminedtobe1031psia,whichislessthanthe1100psiasecondarysideacceptancecriteria.Therefore,itisconcludedthatincreasedsteamgeneratortubepluggingandtheassociatedreductioninRCSflow,hasnoadverseimpactoncompliancewithover-pressurizationcriteriaforthedecreaseinheatremovalbythesecondarysystemclassoftransients.b.DecreaseinReactorCoolantSstemFlowRateEventswithinthiscategoryoftransientsareinitiatedbyamalfunctionoftheReactorCoolantPumps(RCP)withtheresultantdecreaseincoolantflowcausingadegradationinthecalculatedDNBR(closertothelimitof1.22).TwoeventsinthiscategoryareimpactedbytheproposedreductionindesignRCSflowandlowflowtripsetpoint:LossofReactorCoolantFlow(LOF)andSeizedRCPRotor.(1)LossofReactorCoolantFlowTheLossofFloweventwasevaluatedwiththeinitialconditionsmodifiedtoincludetheproposedchanges.TheobjectiveofthisevaluationwastodeterminewhethertheexistingDNB-LCO(TS3/4.2.5),inconjunctionwiththeRPSLowFlowTrip,willpreventtheDNBRlimitof1.22frombeingviolated.ThiseventisanalyzedonacyclespecificbasisaspartoftheLimitingConditionsforOperation(LCO)setpointverification,becauseitisthemostlimitingAnticipatedOperationalOccurrence(AOO)withrespecttoDNBR.After St.LucieUnit1DocketNo.50-335ProposedExigent,LicenseAmendmentThermalMarinandRCSFlowLimitsL-96-141Attachment2Page7of16accountingfortheproposedRCSflowreduction,reducedlowflowtripsetpoint,andincreasedtubeplugging,thetransientwasevaluatedforCycle14reloadbyapplyingdeterministicpenaltiestotheavailablepowermargin.Resultsofthisevaluationshowareductionintheminimumpowermarginfrom6.8>to1.9%ofratedpower.TheavailablemarginconfirmsthattheminimumDNBRisgreaterthanitslimitvalueof1.22.Or,equivalently,theLOFeventinitiatedwithintheexistingDNBLCOconstraintswillnotresultinviolationoftheSpecifiedAcceptableFuelDesignLimit(SAFDL)forDNBR.(2)SeizedRCPRotorTheseizedrotorevent,isassumedtobeinitiatedbyaninstantaneousseizureofoneofthereactorcoolantpumpshafts.Becauseoftheverylowprobabilityassociatedwiththisevent,alimitednumberoffuelrodfailuresarepermittedtooccur.ThiseventwasevaluatedtoassessthenumberoffuelrodsexpectedtofailasaresultoftheproposedchangestotheRCSflowandthelowflowtripsetpoint.AdecreaseintheRCSflowandareductioninthelowflowtripsetpointwillresultinlowerDNBRsandahigherpercentageoffuelrodfailuresforthisevent.Theresultsoftheanalysisofrecordshowthat,1'.ofthefuelrodswillfail.Theanalysisofrecordforradiologicalconsequencesconservativelyassumedfuelfailuresof2.54.Themarginavailableinthisanalysis,duetoexcessconservatisminthereactorpowerandRadialPeakingFactor(Fr),.hasbeendeterminedtonearlyoffsettheeffectsofthedecreasedcoolantflowandreducedlowflowtripsetpoint,resultinginanetpowerpenaltyof0.57:.ThesmalldecreaseinDNBRassociatedwiththe0.57%powerpenaltywillnotcausethefuelrodfailurestoincreasefromthepresentvalueof14tomorethan2.5%valueusedintheradiologicalanalysis,particularlywiththestatisticaltreatmentofpowerusedintheseizedrotoranalysis.Therefore,FPLhasconcludedthattheimpactofincreasedSGTP,reducedRCSflow,andreducedlowflowtripsetpointonthefuelfailurerateresultingfromtheSeizedRCPRotoraccidentisacceptable.c.ReactivitandPowerDistributionAnomaliesTheeventsinthiscategoryarenotimpactedbythechangeinlowflowtripsetpoint.OnlythedroppedCEAtransientrequiredevaluationduetothereducedRCSflow.

~~St.LucieUnit1DocketNo.50-335ProposedExigentLicenseAmendmentThermalMarinandRCSFlowLimitsL-96-141Attachment2Page8of16DroedCEAThistransientisexplicitlyanalyzedeachcycleaspartoftheDNB-LCOsetpointverification.ThiseventcausesanasymmetryinthecorepowerpeakingdistributionanditsconsequencesonDNBRdependonthecycletocyclefuelloadingpatterncharacteristics.Resultsoftheevaluationperformed,afteraccountingfortheproposedchanges,showareductionintheminimumpowermarginfrom8.04to4.6%ofratedpower.Basedontheavailablemargin,itisconcludedthattheoccurrenceofaCEAdropevent,afterimplementationoftheproposedchanges,willnotresultinviolationoftheDNBRSAFDL,providedthetransientisinitiatedwithintheconstraintsoftheDNBLCO.d.DecreaseinReactorCoolantInventorEvents(1)LareBreakLOCALBLOCAThiseventwasevaluatedtoaccountfortheimpactoftheproposedchangesonthepeakcladdingtemperature.Theeffectsontheblowdownandre-floodphasesofthetransientduetoalowerinitialsecondarypressure(resultofhighertubeplugging)andanincreasedcoreaveragetemperature(resultoflowerRCSflow)wereestimatedtoresultinaminorimpactonthecalculatedpeakcladdingtemperature(PCT),wellwithintheconservatismintheanalysisasdescribedbelow.Theanalysisofrecordusesaconservativecombinationofinitialfuelpelletstoredenergyandaxialpowerprofilestoboundtheentirecycleofoperation.Additionalconservatismliesintheassumptionofamaximumresinterdensityof1.14comparedto0.81%as-builtvalueforCycle14.Theuseofanas-builtresinterdensityisestimatedtoresultinareductionininitialfuelaveragetemperatureof34FforthecaseoffuelstoredenergynearBOCandatleast16FforthecaseoffuelstoredenergyrepresentingMOC.ThisamountofconservatisminthefuelstoredenergyrepresentsasignificantconservatisminPCT,andtheanalysisofrecordwouldcontinuetoremainbounding.AdditionaldiscussioninvolvingtheLBLOCAevaluationisprovidedintheenclosedreport,EMF-96-135.Itisconcludedthat,aLBLOCAinitiatedfromplantconditionsconsistentwiththeproposedchanges,willhaveconsequenceswhichsatisfytherequirementsof10CFR50.46(b).

St.LucieUnit1DocketNo.50-335ProposedExigentLicenseAmendmentThermalMarinandRCSFlowLimitsL-96-141Attachment2Page9of16(2)SmallBreakLOCASBLOCATheSmallBreakLOCAeventforSt.LucieUnit1wasevaluatedfortheimpactofthereducedprimarysystemflowandtheincreasedS/Gtubeplugginglevel(30:average).IncreasedS/GtubepluggingwillresultinareductionintheinitialRCSinventorywhichcouldcauseadeepercoreuncovery.Also,asmallincreaseintheprimarysystemaveragetemperatureduetothelowerRCSflowwilltendtoslowthedepressurization,delayingsafetyinjection.Theseeffects,however,aresmall.Theresultsofthiseventareinfluencedmorebychangestothetop-peakedaxialprofiles.Theanalysisofrecordusesatop-peakedaxialprofilefromtheend-of-cycle(EOC)conditions.AreviewofCycle14axialprofilesshowedthatthemaximumpeakpowerelevationcorrespondingtothemiddle-of-cycle(MOC)waslowerthanthatusedintheanalysisofrecord.TheaverageburnupoftheMOCaxialprofileswas7000EFPH.Theconservatismintheanalysisduetothisaxialprofile,uptothisburnup,willoffsetanyadverseeffectsduetotheincreasedtubeplugginganddecreasedRCSflow.AdeterminationoftheoffsettingeffectsbeyondMOCwasnotpossiblewithoutquantifyingtheeffectsbyre-analysis.However,sinceSBLOCAisverysensitivetocorepower,areductioninthereactorthermalpowerto90:ofratedpowerbeyond7000EFPHofoperationisestimatedtoprovidesufficientmargintooffsetanyadverseeffectsoftheproposedchanges.Thisreductionincorethermalpowerisestimatedtoreducethemassinventorylostoutofthebreak,whichisapproximatelytwiceaslargeasthereductionininitialinventorycausedbytheincreasedtubeplugging.Also,theprimarysystempressurewilldecreasemorerapidlybecauseofthelowersteamgenerationrateintheprimarysystem.Theanalysisofrecord,therefore,wouldremainbounding.Additionaldiscussioninvolvingthe904powerconstraintisprovidedinSection3.2.6.4oftheenclosedreport,EMF-96-135.ItisconcludedthatthecurrentSBLOCAanalysiswillboundCycle14operationonlyupto7000EFPH.

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St.LucieUnit1DocketNo.50-335ProposedExigentLicenseAmendmentThermalMarinandRCSFlowLimitsL-96-141Attachment2Page10of16e.UncontrolledCEAWithdrawalBoththeuncontrolledCEAwithdrawalfromlowpowerandtheCEAwithdrawalinitiatedfromhighpowerconditionsareeventsanalyzedagainstDNBRcriteria.ThemostlimitinganticipatedoperationaloccurrencefromtheDNBconsiderationsistheLossofFloweventwhichwasevaluatedandpreviouslydiscussedinSection4.b(1).SincetheproposedreductioninRCSflowisexpectedtoaffecttheDNB-relatedeventsinasimilarmanner,theCEAwithdrawaleventwillcontinuetoremainboundedbytheLossofFlowtransient.SincetheLOFanalysisresultsareacceptable,it.isconcludedthattheuncontrolledCEAwithdrawalwillnotresultinviolationoftheDNBRSAFDL,wheninitiatedfromwithintheDNB-LCO.BoronDilutionEventAborondilutioneventcanoccurduringanymodeofplantoperations.ProtectionagainstviolationofSAFDL'sforborondilutioneventsinitiatedatpowerisprovidedbytheexistingTM/LPtrip,theVariableHighPowerTrip(VHPT)andtheLPDLSSS.IncreasedS/GtubepluggingwillresultinasmallchangeinRCSfluidvolume(-1.28%).Thisinturnwillimpactthetimetocriticalitydeterminedintheborondilutioneventanalyses.Thereferenceanalysesfordilutioneventsinitiatedfromhotstandbyorhot/coldshutdownconditionsatSt.LucieUnit1,showthatmarginexiststotheacceptancecriteriainthetime.tocriticality.SinceMode6onlyconsidersthemassinventoryinthe,reactorvessel,theincreaseinS/GtubepluggingdoesnotaffectMode6.ForModes2to4,thedecreaseintheRCSinventorywascalculatedtoreducethetimetocriticalityfrom72.02minutesto71.1minutes.Thistimeisgreaterthantheacceptancecriteriaof15minutes.ThetimetocriticalityforMode5reducedfrom20.54minutesto20.3minutes,relativetothecriteriaof15minutes.Theborondilutioneventresultsare,therefore,acceptablefortheproposedchanges.g,CEAE'ectionAccidentsAcontrolrodejectionaccidentisdefinedasthemechanicalfailureofacontrolrodmechanismpressurehousingresulting St.LucieUnit1DocketNo.50-335ProposedExigentLicenseAmendmentThermalMarinandRCSFlowLimitsL-96-141Attachment2Page11of16intheejectionofaCEAanditsdriveshaft.Theconsequenceofthismechanicalfailureisarapidreactivityinsertionandanadversecorepowerdistribution,whichmayresultinlocalizedfueldamage.4IncreasedS/Gtubepluggingwillhavenosignificanteffectontheresultsofthistransientbecausepredictionsoffuelfailurearebasedonfuelcenterlinemeltcriteria(depositedenergyinthefuelrod),notonDNBRcriteria.Therefore,,areductioninRCSflowproposedhere,willnotimpacttheresultsofthiseventwithrespecttocoredamageoroffsiteradiologicaldoseconsequences.Inadvertent0eninofPressurizerPressureReliefValvesAlthoughthiseventisthemostDNB-limitingwithinthe"DecreaseinReactorCoolantInventory"categoryoftransients,itisboundedbytheLossofFlowevent.SincetheproposedchangeswillnotaffecttherelativebehaviorofDNBRbetweenthetwotransients,thiseventwillcontinuetoremainboundedbytheLossofFlowevent.TheinadvertentPORVopeningisalsooneofthetransientsusedinthedeterminationofthelimitingpressurebiastermintheTM/LPequation.ThisbiastermisdependentonthemaximumrateofchangeofDNBRexperiencedduringtheevent,whichforthiscase,isdirectlydependentontherateofdepressurization.Sincetheproposedchangesdonot.affectthedepressurizationrateinthistransient,itisconcludedthatthereisnoimpactontheexistingTM/LPpressurebias.SteamGeneratorTubeRutureSGTRExistinganalysesoftheSGTReventdemonstratethepotentialradiologicalconsequencesofthistransient.Theseanalyseshaveconcludedthattheassociatedradiologicalreleaseisprimarilydependentonthebreakflowrateandthecorrespondingprimary-to-secondarymasstransferduringtheevent.Theradiologicalreleasesweredeterminedtobeasmallfractionof10CFR100limits.Thedifferentialpressure(primary-to-secondary)acrossthesteamgeneratortubesdeterminesiftheflowthroughthebreakischokedornot.Theexistinganalysisofrecordexaminedtheboundingcasewherebreakflowwaschokedbeforereactorscram.Afterreactorscram,thetransientresponseisgovernedbytheopeningofsteamdumpandbypassvalves.

St.LucieUnit1DocketNo.50-335ProposedExigentLicenseAmendmentThermalMarinandRCSFlowLimitsL-96-141Attachment2Page12of16ThepostulatedincreaseinS/GtubeplugginglevelwillresultinreducedsecondarysideoperatingpressureatSt.LucieUnit1.ThischangecouldresultinslightlylongertimesofchokedflowforanactualSGTR.However,theanalysisofrecordassumeschokedflowconditionsduringtheperiodofinterestbeforereactorscram,andthereforewillremainbounding.Itis,therefore,concludedthattheproposedchangeswillnotalterthesystemresponseandtheresultantpotentialoffsitedoseconsequencesfortheSGTRevent.j.IncreaseinHeatRemovalbtheSecondarSstemEventsinthiscategoryareevaluatedbycalculatingtheincreaseinprimarysystemcoolingduetotheparticulareventinitiator.NoneoftheeventsinthiscategoryareadverselyimpactedbytheproposedincreaseinsteamgeneratortubepluggingorreducedRCSflowandlowflowtripsetpoint.Adiscussionoftheindividualtransientevaluationsfollows.(1)ExcessLoadThreeeventswithdifferentinitiatorsarepostulatedwiththelimitingsub-eventbeingtheinadvertentopeningofallthesteamdumpandbypasssystemvalvesatfullpower.Thisscenariowouldresult,inanapproximate43.4%increaseinsteammassflowrate.ThiseventhasbeendeterminedtobeboundedbytheLossofFloweventforDNBconsiderationsandnoneoftheproposedchangeswillsignificantlyimpacttherelativeDNBRbehaviorbetweenthesetwotransients.Therefore,noreanalysisofthiseventwasrequired.(2)SteamSstemPiinFailuresInsideOutsideContainmentSteamSystemPipingFailureeventsareanalyzedtoensurethatanyfuelfailureswhichmightoccurarelimitedtoasmallpercentageofthefuelinthecore.Theseanalyses,areusedtodeterminewhetherfuelfailureswouldresultfromviolationofeithertheDNBRorfuelcenterlinemeltSAFDL's.BecausetheinitialcorepowerdistributionhasnotbeenchangedandsincethetimeofminimumDNBR,inthelimitingcase,occursduringaperiodofnaturalcirculationflow,thekeyparameteraffectingfuelfailuresisthereturntopowerlevelcausedbyreactivityfeedbackfollowingthebreak.TheprimarysystemcooldownfollowingalimitingsteamsystempipingfailureinitiatedwithincreasedsteamgeneratortubepluggingandreducedRCSflowwillbeboundedby(nomore St.LucieUnit1DocketNo.50-335ProposedExigentLicenseAmendment.ThermalMarinandRCSFlowLimitsL-96-141Attachment2Page13of16severethan)theexistinganalysis.Thereducedprimarytosecondaryheattransferrateacrossthesteamgeneratorandthelowerinitialsecondarypressurebothcontributetomakethisamorebenignevent.Theseeffectsensurethattheexistinganalysisofrecordforsteamsystem.pipingfailureswillremainboundingandpotentialoff-sitedoseconsequencesremainunchanged.(3)Inadvertent0eninofaSteamGeneratorReliefAtmoshericDumValveThiseventisnormallyevaluatedtoassessradiologicalconsequences.Radiologicalreleasescausedbythiseventwillbelesssevereandlesslikelytooccurafterimplementationoftheproposedchangesbecauseofthelowerinitialsecondarysidepressureresultingfromtheincreasedsteamgeneratortubeplugginglevel.Theanalysisof.recordassumesconservativeTechnicalSpecificationlimitsfortheprimarytosecondaryleakratewhichremainsunchanged.Therefore,theexistinganalysisofrecordwillremainboundingforthisevent.k.Theimpactoftheproposedchangesonrelevantsetpointanalyseswasalsoevaluated.ThesetpointanalysesincludetheReactorProtectionSystem(RPS)LocalPowerDensity(LPD)LSSS,LPDLimitingConditionforOperation(LCO),ThermalMargin/LowPressure(TM/LP)LSSS,andtheDNBLCOforallowablecorepowerasafunctionofAxialShapeIndex(ASI).VerificationofthevalidityofthesesetpointsisdiscussedinSection4.0ofEMF-96-135.5.EvaluationofOtherSelectedUFSARAnalsesWhilethediscussioninSections3and4focusedontheimpactoftheproposedRCSflowreductionandincreasedsteamgeneratortubepluggingontheresultsoftheplantUFSARChapter15SafetyAnalysis,acompleteevaluationoftheimpactoftheproposedchangesrequirestheevaluationofseveraladditionalissues.Thesearesummarizedbelow.a.PlantNaturalCirculationCaabilitFPLhasexaminedtheincreasedtubepluggingtodetermineifanyadverseimpactonnaturalcirculationcoolingcapabilitywouldresult.

St.LucieUnit1DocketNo.50-335ProposedExigentLicenseAmendmentThermalMarinandRCSFlowLimitsL-96-141Attachment2Page14of16ThecalculationsperformedbyFPLinsupportofthecurrentanalysislimitof25:(+7:)tubepluggingshowedthatnaturalcirculationcapabilitieswith18%and324SGTPwereverysimilar,withcoldlegtemperaturesdifferingbylessthan1F(FPLletterL-93-035;3/19/93insupportofLicenseAmendment130).Thesimulationwasperformedassumingnooperatoractions,andwithheatremovalbytheSGsafetyvalves.FPLdeterminedthatthecooldownratewasdominatedbyoperationofthesecondarysafetyvalves,andthatincreasedSGTPhadnoadverseimpact.Therefore,FPLhasconcludedthattheproposedchangeswillnotpreventtheoccurrenceofnaturalcirculation.b.PeakContainmentPressurizationFollowinLBLOCAorSteamSstemPiinFailurecoLargeBreakLOCAandSteamPipeBreakInsideContainmentanalysesofrecordwereevaluatedtodetermineifthereducedRCSflowand/orincreasedtubeplugginglevelwouldcausethecontainmentdesignpressurevaluetobeexceeded.FortheLBLOCAeventinsidecontainment,thereductioninprimarysystemfluidvolumeavailableforblowdown,ahigherresistancetoblowdown,andlesssecondarytoprimaryheat.transfercompletelyoffsettheeffectsfromaslightincreaseinsystemenergyduetothehigherinitialRCSTave.Thepeakpressureintheanalysisofrecordwillremainbounding.SteamPipingFailuresinsidecontainmentwerealsoexaminedanditwasconcludedthat,afterallowingfortheproposedchanges,nocompromiseofthepressurelimitsoncontainmentanalysiswouldresult.Increasedtubepluggingwillresultinasmallincreaseinthetotalsecondarysidemassinventory,butthattheoverallenergystoredinthefluid(andeventuallyreleasedtocontainmentduringthisevent)isnotincreased.Inaddition,thelowerinitialsecondarypressurewillallowlessblowdown(fromtheintactS/G)priortoMainSteamIsolationSignal(MSIS).AuxiliarFeedwaterSstemAFWHihEnerLineBreakTheexistingsystemevaluationfortheAFWsystemidentifiedthiseventinconjunctionwithlossofoffsitepowerasthelimitingconditionforplantoperatorstobeabletoinitiateauxiliaryfeedwaterflow.Theanalysisforthiseventwasevaluatedwithrespecttotheincreasedaverageprimarycoolanttemperature.Itwasdeterminedthatanadditional637

~v~~St.LucieUnit.1DocketNo.50-335ProposedExigentLicenseAmendmentThermalMarinandRCSFlowLimitsL-96-141Attachment2Page15of16ibmofinventorywouldbeboiledofffromthesecondarysidereducingthedryouttimefrom650secondsto611.7seconds.Nocredit,wastakenfortheincreasedinitialsecondarysidemassinventory.ItisconcludedthatallacceptancecriteriawillbesatisfiedwithincreasedsteamgeneratortubepluggingandreducedRCSflow.d.LowTemeratureOverressureProtectionLTOPAnalsisTheexistingLTOPanalysiswasevaluatedtodeterminewhetherthepostulatedincreaseinsteamgeneratortubepluggingwouldimpacttheconsequencesofstartingaRCPwiththeplantsecondarysideatahighertemperaturethantheprimaryside.PlugginganincreasednumberofS/Gtubeswasdeterminedtoresultinaslightincreaseofthethermaltimeconstantofthesystem,whichforthiseventleadstoaslowerrateofenergyadditiontotheprimaryside.OnlyachangeintheRCPheatoutputorintheinitialconditionofprimarytosecondaryhTcouldchangetheenergydepositedintheprimarysystem,andhence,thepeakpressure.Therefore,increasingthesteamgeneratoraveragetubepluggingto30:hasnoadverseimpactonthepressurespikecausedbystartingaRCPpumpunderlowtemperatureconditions.e.OverressureProtectionAnalsisInAppendix5AoftheSt.Lucie1UFSAR,ananalysisdocumentingthesizingoftheprimaryandsecondarysafetyvalvesispresented.Theintentofthisanalysis,whichisbasedona"worstcase"lossofloadevent,istosizethesafetyvalves.Thesafetyvalveflowratesarechosensuchthatthepeaksystempressureislessthan110%ofdesign.TheimpactoftheproposedincreaseinsteamgeneratortubepluggingandreducedRCSflowonthelicensinganalysisfortheLossofExternalLoadeventwaspreviouslydiscussed(seeSection4.a).Sincethatanalysisconfirmedcompliancewiththepressurizationcriteria,itindirectlyverifiedthecontinuedvalidityofthemainsteamsafetyvalvesizinganalysisofreference.Therefore,itisconcludedthattheproposedchangesdonotrequireanincreaseinmainsteamsafetyvalvecapacitytosatisfytheoverpressurizationcriteria.

St.LucieUnit1DocketNo.50-335ProposedExigentLicenseAmendmentThermalMarinandRCSFlowLimitsL-96-141Attachment2Page16of16ImactonSteamGeneratorMechanicalLoadsThesteamgeneratorinlettemperaturecorrespondingto345,000gpmRCSdesignflowiscalculatedtobelessthan604F.Thetemperaturevalueof604FissupportedbytheS/Gmechanicalloadcalculationsperformedfor25>+7>asymmetrytubepluggingcase.Therefore,thereisnoadverseimpactonanyacceptancecriteriaforthetubesheetandsteamgeneratortubebundle,andsufficientmargintostresslimitswillremainavailable.6~ConclusionReactorcorethermalmarginsafetylimitsillustratedinTSFigure2.1-1havebeenadjustedtoaccountfortheproposedvalueofdesignRCSflow,anddefinetheareasofsafeoperationintermsofthermalpower,RCSpressure,andcoldlegtemperatureforwhichtheDNBRisnolessthantheMDNBRlimit.TheminimumDNBRlimitfor-steadystateoperation,normaloperationaltransients,andanticipatedtransientsremainsunchangedfromtheexisting,approvedvalueof1.22.ThevalidityofReactorProtectiveInstrumentationsettingsandtripfunctionsinconjunctionwithrelatedLimitingConditionsforOperationhasbeenverifiedtoprovideassurancethatreactorcoredesignlimitsarenotexceededfortheproposedchangeinRCSdesignflow.TheassessmentsperformedofrelevantsafetyanalysesforSt.LucieUnit1demonstratethatestablishedacceptancecriteriaforplantperformancewillremainsatisfiedduringoperationwiththeproposedamendment,whichincludesaderatetog90%ratedthermalpowerforoperationbeyond7000EFPHinCycle14.Inaddition,potentialradiologicalconsequencesdeterminedintheanalysesofrecord,andwhichdemonstratecompliancewith10CFR100acceptancecriteriawillremainboundingforoperationwiththereducedRCSflowandincreasedSGTP.Therefore,FPLconcludesthatoperationofthefacilityinaccordancewiththisproposedamendmentisacceptable.

))~~~St.LucieUnitIDocketNo.50-335ProposedExigentLicenseAmendmentThermalMarinandRCSFlowLimitsATTACHMENT3DETERMINATIONOFNOSIGNIFICANTHAZARDSCONSIDERATION St.LucieUnit1DocketNo.50-335ProposedExigentLicenseAmendmentThermalMarinandRCSFlowLimitsL-96-141Attachment3Page1of2DETERMINATIONOFNOSIGNIFICANTHAZARDSCONSIDERATIONDescritionof'mendment:TheproposedlicenseamendmentchangestheTechnicalSpecifications(TS)byreducingthedesignreactorcoolantflowwithfourreactorcoolantpumpsoperatingfrom355,000gpmto345,000gpm(TABLE2.2-1andTABLE3.2-1),revisingthereactorcorethermalmarginsafetylimitsshowninFIGURE2.1-1,andmodifyingthereactorcoolantsystemtotalwaterandsteamvolumedescribedindesignfeaturessection5.4.2.TheamendmentalsoreducesthereactorcoolantlowflowtripfunctionLimitingSafetySystemSetting(LSSS)from>95%toh93%ofdesignreactorcoolantflow.Finally,TS2.1.1ismodifiedtorestrictreactorpowertoS904ratedthermalpowerforoperationbeyond'iddleofCycle14.TherevisionsaremadetosupportchangesinthesafetyanalyseswhichaccommodatealargernumberofpluggedsteamgeneratortubesforOperatingCycle14.Pursuantto10CFR50.92,adeterminationmaybemadethataproposedlicenseamendmentinvolvesnosignificanthazardsconsiderationifoperationofthefacilityinaccordancewiththeproposedamendmentwouldnot:(1)involveasignificantincreaseintheprobabilityorconsequencesofanaccidentpreviouslyevaluated;or(2)createthepossibilityofanewordifferentkindofaccidentfromanyaccidentpreviouslyevaluated;or(3)involveasignificantreductioninamarginofsafety.Eachstandardisdiscussedasfollows:(1)Operationofthefacilityinaccordancewiththeproposedamendmentwouldnotinvolveasignificantincreaseintheprobabilityorconsequencesofanaccidentpreviouslyevaluated.Theproposedamendmentdefinesreactorcorethermalmarginsafetylimitsforareducedvalueofdesignreactorcoolantflow,andestablishesarevisedLimitingSafetySystemSetting(LSSS)fortheprotectivesystemlowflowtrip.Ascoreprotectionvariables,theselimitingparametersarenotaccidentinitiatorsanddonotaffectthefrequencyofoccurrenceofpreviouslyanalyzedtransients.Thedesignfeatures'otalwaterandsteamvolumerevisionaccountsforsteamgeneratortubepluggingandissimplyadministrativeinnature.Evaluationsperformedtoassesstheimpactoftheproposedamendmentconcludethat,whenconsideringaunitderateto90>ratedthermalpowerforoperationbeyond7000EFPHinCycle14asrequiredbytheproposedchangetoTS2.1.1,thepotentialradiologicalconsequencesofpreviouslyanalyzed St.LucieUnit1Docket,No.50-335ProposedExigentLicenseAmendment'hermalMarinandRCSFlowLimitsL-96-141Attachment3Page2of2transientswillconservativelyremainwithinestablishedacceptancecriteria.Therefore,operationofthefacilityinaccordancewiththisamendmentwouldnotinvolveasignificant.increaseintheprobabilityortheconsequencesofanyaccidentpreviouslyevaluated.(2)Operationofthefacilityinaccordancewiththeproposedamendmentwouldnotcreatethepossibilityofanewordifferentkindofaccidentfromanyaccidentpreviouslyevaluated.Theproposedamendmentreviseslimitingparameterstoassuresafeoperationcommensuratewiththeimpactofsteamgeneratortubeplugging,andwillnotchangethemodesofoperationdefinedinthefacilitylicense.Theanalysisoftransientsassociatedwithsteamgeneratorfailuresarepartofthedesignandlicensingbases.Therefore,operationofthefacilityinaccordancewith.theproposedamendmentwouldnotcreatethepossibilityofanewordifferentkindofaccidentfromanyaccidentpreviouslyevaluated.t3)Operationofthefacilityinaccordancewiththeproposedamendmentwouldnotinvolveasignificantreductioninamarginofsafety.TheproposedamendmentallowsfullpoweroperationatanRCSflowcommensuratewith30%(average)steamgeneratortubepluggingforCycle14fuelbatchaverageburnupconditionscorrespondingtomid-cycle.Foroperationbeyondmid-cycle,reactorpowerwillberestrictedto<90%ratedthermalpower.AnevaluationoflimitingeventstoestablishedacceptancecriteriaforSpecifiedAcceptableFuelDesignLimits(SAFDL),primaryandsecondaryoverpressurizationtransients,10CFR50.46(b)emergencycorecoolingsystemsacceptancecriteria,peakcontainmentpressure,potentialradiationdoseduringaccidents,andtoTSLimitingConditionsforOperationhasbeencompletedinsupportofthisamendmentrequest.Theevaluationconcludes,whenconsideringtheproposedLSSSfortheLowFlowtrip,thataconservativemargintoacceptablelimitsremainsavailable.Therefore,operationofthefacilityinaccordancewiththisproposedamendmentwouldnot.involveasignificantreductioninamarginofsafety.Basedontheabovediscussionandthesupportingevaluationoftechnicalspecificationchanges,FPLhasdeterminedthattheproposedlicenseamendmentinvolvesnosignificanthazardsconsideration.