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)

Text

DOCKET05000335NOTES:CATEGORY1,REGULPT%INFORMATION DZSTRIBUTIOlZSTEM (RIDE)IACCESSION NBR:9606030191 DOC.DATE:

96/06/01NOTARIZED:

YESFACIL:50-335 St.LuciePlant,Unit1,FloridaPower6LightCo.AUTH.NAMEAUTHORAFFILIATION BOHLKEFW.H.

FloridaPower&LightCo.RECIP.NAME RECIPIENT AFFILIATION 5~DocumentControlBranch(Document ControlDesk)p~

SUBJECT:

Application forexigentamendtolicenseDPR-67,revising TS~pge.PrrethermalmarginaRCSflowlimits.SiemensPowerCorpReptEMF-96-135, "StLucieUnit1Chapter15EventRview6Analysisfor30%SGTubePlugging" encl.DISTRIBUTION CODE:AOOZDCOPIESRECEIVED:LTR lENCLjSIZE:ZkTITLE:ORSubmittal:

GeneralDistribution ERECIPIENT IDCODE/NAME PD2-3LAWIENS,L.INTERNAL:

ACRSNRR/DE/EMCB NRR/DSSA/SPLB NUDOCS-ABSTRACT EXTERNAL:

NOACCOPIESLTTRENCL1~1111111111111RECIPIENT IDCODE/NAME PD2-3PDNRR/DRCH/HICB NRR/DSSA/SRXB OGC/HDS3NRCPDRCOPIESLTTRENCL1111111110110DENTNOTETOALL"RIDS"RECIPIENTS:

PLEASEHELPUSTOREDUCEWASTE!CONTACTTHEDOCUMENTCONTROLDESK,ROOii!OWFN5D-5(EXT.

415-2083)

TOELIMINATE YOURNAMEFROMDISTRIBUTION LISTSFORDOCUMENTS YOUDON'TNEED!TOTALNUMBEROFCOPIESREQUIRED:

LTTR13ENCL12 FloridaPower5LightCompany,P.O.Box128,FortPierce,FL34954-0128 June1,1996'-96-141 10CFR50.9010CFR50.91U.S.NuclearRegulatory Commission Attn:DocumentControlDeskWashington, D.C.20555Re:St.LucieUnit1DocketNo.50-335ProposedExigentLicenseAmendment ThermalMarinandRCSFlowLimitsPursuantto10CFR50.90,FloridaPower6LightCompany(FPL)requeststoamendFacilityOperating LicenseDPR-67forSt.LucieUnit1byincorporating theattachedTechnical Specifications (TS)revisions.

Basedonsafetyanalysesassumptions of30'average) ofallsteamgenerator tubesremovedfromservice,theamendment.

reducesthestatedvalueofdesignreactorcoolantflowfrom355,000gpm'to345,000gpm,revisesthereactorcorethermalmarginsafetylimitsshowninFIGURE2.1-1,andmodifiesthereactorcoolantsystemtotalwaterandsteamvolumedescribed inthedesignfeatures.

Theamendment alsoreducestheLimitingSafetySystemSettingforthereactorcoolantlowflowtripfunctionfrom>95%to2934ofdesignreactorcoolantflow.Finally,TS2.1.1ismodifiedtolimitreactorpowerto<90'atedthermalpowerforCycle14operation exceeding mid-cycle fuelburnupconditions.

Itisrequested thattheproposedamendment, ifapproved, beissuedbyJune20,1996,tofacilitate timelyresumption ofpoweroperations.

FPLbelievesthatthepresentsituation atSt.LucieUnit1satisfies therequisite conditions forissuanceofanexigentamendment andherebyrequestsconsideration ofthissubmittal pursuantto10CFR50.91(a)(6).

Attachment 1providesthebasisforconsideration oftherequest.asanexigentamendment.

Attachment 2isanevaluation oftheproposedTSchange.Attachment 3isthe"Determination ofNoSignificant HazardsConsideration."

Attachment 4containsacopyoftheappropriate TSpagesmarked-up toshowtheproposedchanges.Enclosedwiththissubmittal isacopyof"SiemensPowerCorporation-Nuclear

Division, St.LucieUnit1Chapter15EventReviewandAnalysisfor304SteamGenerator TubePlugging, EMF-96-135;May,1996"PbOb030000gg5qbObOiPDRADQCK0PPDRanFPLGroupcompany h~

St.LucieUnit1DocketNo.50-335ProposedExigentLicenseAmendment ThermalMarinandRCSFlowLimitsL-96-141Page2Theproposedamendment hasbeenreviewedbytheSt.LucieFacilityReviewGroupandtheFloridaPower6LightCompanyNuclearReviewBoard.Inaccordance with10CFR50.91(b)(1),acopyoftheproposedamendment isbeingforwarded totheStateDesigneefortheStateofFlorida.Pleasecontactusifthereareanyquestions aboutthissubmittal.

Verytrulyyours,W.H.BohlkeVicePresident NuclearEngineering andLicensing WHB/RLDAttachments Enclosure cc:StewartD.Ebneter,Regiona'l Administrator, RegionII,USNRC.SeniorResidentInspector, USNRC,St.LuciePlant.Mr.W.A.Passetti, FloridaDepartment ofHealthandRehabilitative Services.

St.LucieUnit1=DocketNo.50-335ProposedEmergency LicenseAmendment ThermalMarinandRCSFlowLimitsL-96-141Page3))COUNTYOFST.LUCIE)SS.W.H.Bohlkebeingfirstdulysworn,deposesandsays:ThatheisVicePresident, NuclearEngineering andLicensing, fortheNuclearDivisionofFloridaPower6LightCompany,theLicenseeherein;Thathehasexecutedtheforegoing document;

.thatthestatements madeinthisdocumentaretrueandcorrecttothebestofhisknowledge, information andbelief,andthatheisauthorized toexecutethedocumentonbehalfofsaidLicensee.

W.H.BohlkeSTATEOFFLORDACOUNTYOF,~CA~Theforegoing instrument wasacknowledged beforemethisdayof,19'7(byW.Bohlke,o'ersonally knowntomeandwhdidtakah..+MYou)z(~

NameofNotaryPublicMyCommission expiresRRE'ommission No.EALOFHCIALNOTARYSKARENEGUTOWSKINOI'ARYPUBLICSTATEOFFLORIDACOMMISSION NO.CC387743MYCOMMISSION EXP.LY30,1998

~~hP

~L~1St.LucieUnit1DocketNo.50-335ProposedExigentLicenseAmendment ThermalMarinandRCSFlowLimitsATTACHMENT 1BASISFOREXIGENTAMENDMENT CONSIDERATION Se

~~~zSt.LucieUnit1DocketNo.50-335ProposedExigentLicenseAmendment ThermaMarinandRCSFlowLimitsL-96-141Attachment 1Page1of2BASISFOREXIGENTAMENDMENT CONSIDERATION Pursuantto10CFR50.91(a)(5) and(6),theNRCmayadjudgethatanemergency orexigentsituation exists,inthatfailureoftheNRCtoactinatimelywayonarequestforlicenseamendment wouldresultinprevention ofresumption ofoperation ofanuclearpowerplant.Forconsideration ofthisprovision, thelicenseeisrequiredtoexplainwhytheemergency orexigentcircumstance occurredandwhyitcouldnotbeavoided.TheNRCwillthenassessthelicensee's reasonsforfailingtofiletheapplication sufficiently inadvanceoftheevent,andifitdetermines thatthelicenseehasnotabusedtheemergency/exigent provision, itmayissuealicenseamendment involving nosignificant hazardsconsideration withoutthe30daysnormallyallowedforpriornoticeandopportunity forahearingorforpubliccomment.Adiscussion ofwhythepresentsituation atSt.LucieUnit1satisfies therequisite conditions forissuanceofanexigentamendment follows.1.WhtheExiencOccurredandCouldNotbeAvoided.OnApril29,1996,St.LucieUnit1enteredascheduled refueling outage.Amarginofapproximately 14%existedbetweentheaveragenumberofsteamgenerator (SG)tubesthathadbeenpreviously removedfromserviceandthenumberofpluggedtubesassumedinthesafetyanalyses.

Basedona10yearhistoryof1004EddyCurrentTesting(ECT),andincluding additional inspection commitments pursuanttogenericletter(GL)95-03,"Circumferential CrackingofSteamGenerator Tubes,"thenumberoftubesconservatively estimated toberemovedfromserviceduringthisoutagewasfarlessthantheremaining analytical margin.Basedonconcernsinvolving thequalification oftechniques forsizingSGtubecrack-like indications thatwerecommunicated toindustrybytheNRCstaffattheNRCRegulatory Information Conference heldApril9-10,1996,FPLmadeapro-active presentation tothestaffonApril22,1996,outlining thestatusofSGcondition, ECTtechnique qualification, andscheduled refueling outageplansfortheSt.LucieUnit1SGs.Inafollowuptelephone conversation withthestaffonMay7,1996,thestaffquestioned therepaircriteriawhichhavebeeninplaceatFPLsince1985.FPLsubsequently agreedtoimplement amoreconservative criteriafortheCycle14inspection.

FPLdocumented thiscommitment asoutlinedinFPLletterL-96-129datedMay14,1996.Ourassessment, oftheimpactofimplementing thiscriteriaindicates thatthenumberofSGtubestobepluggedmayexceedtheexisting254(average) analyseslimit.

St.LucieUnit1DocketNo.50-335ProposedExigentLicenseAmendment ThermalMarinandRCSFlowLimitsL-96-141Attachment 1~Page2of22.BasisfortheExientAmendment Reuest.Steamgenerator tubeinspections atSt.Luciemeetorexceedcriteriacontained intheSt.LucieUnit1Technical Specifications, andPWRSteamGenerator Examination Guidelines, Revision3,EPRIReportNP-6201,November, 1992.Uponcompletion ofreviewandevaluation ofdatabyindustrygroupsandFPL,newtechnology hasbeenroutinely implemented atSt.Lucieinamannertoprovidealinktopreviousexamination data.Thechangeinrepaircriteriaandthemagnitude ofresultant SGtubepluggingcouldnothavebeenreasonably anticipated priortoNRCstaffconcernshavingbeencommunicated toFPLduringtherecentmeetinganddiscussions.

Theneedforanamendment toimplement revisedSt.LucieUnit1powerandRCSflowlimitscouldnothavebeenanticipated priortoassessing theimpactofthechangeinrepaircriteriafollowing FPL'smeetinganddiscussions withtheNRCstaff.Thenecessary evaluations andpreparation oftheproposedlicenseamendment wereinitiated withoutdelayandattheearliestpractical time.Analysesandqualityassurance verifications tosupporttheproposedlicenseamendment werecompleted inanexpeditious manner,andwereperformed inparallelwiththeongoingtubeexaminations.

FPLexpectstocompletetherefueling overhaulandtherequiredstartuppreparations byJune20,1996.Untilalicenseamendment isissuedtoauthorize operation withtheproposedchanges,resumption ofSt.LucieUnit1poweroperations willbeprevented bythecurrentTechnical Specifications.

Basedonthepreceding discussions, FPLbelievesthatthepresentsituation couldnothavebeenanticipated totheextentthatarequestforamendment couldhavebeenfiledsufficiently inadvance;thattheemergency/exigency provision hasnotbeenabusedbynotmakingatimelyapplication andthusitselfcreatingexigentcircumstances; andthatthislicenseamendment requestsatisfies criteriaforconsideration pursuantto10CFR50.91(a)(6).

St.LucieUnit1DocketNo.'0-335 ProposedExigentLicenseAmendment ThermalMarinandRCSFlowLimitsATTACHMENT 2EVALUATION OFPROPOSEDTSCHANGES St.LucieUnit1DocketNo.50-335ProposedExigentLicenseAmendment ThermalMarinandRCSFlowLimitsL-96-141Attachment 2Page1of16TABLEOFCONTENTS1.Introduction 2.ProposedTSChangesandBases3.GeneralEffectoftheProposedChangesonEventAnalyses4.,Evaluation ofUFSARChapter15Eventsa.DecreaseinSecondary SideHeatRemovalb.DecreaseinReactorCoolantSystemFlowRatec.Reactivity andPowerDistribution Anomalies d.DecreaseinReactorCoolantInventory Eventse.Uncontrolled CEAWithdrawal f.BoronDilutionEventg.CEAEjectionAccidents h.Inadvertent OpeningofPressurizer PressureReliefValvesi.SteamGenerator TubeRupture(SGTR)j.IncreaseinHeatRemovalbytheSecondary Systemk.ReactorProtection Setpoints 5.Evaluation ofOtherSelectedUFSARAnalysesa.PlantNaturalCirculation Capability b.PeakContainment Pressurization Following LBLOCAorSteamSystemPipingFailurec.Auxiliary Feedwater (AFW)HighEnergyLineBreakd.LowTemperature Overpressure Protection (LTOP)e.Overpressure Protection Analysisf.ImpactonSteamGenerator Mechanical Loads6.Conclusion 16 St.LucieUnit1DocketNo.50-335ProposedExigentLicenseAmendment ThermalMarinandRCSFlowLimitsL-96-141Attachment 2Page2of16EVALUATION OFPROPOSEDTSCHANGES1.,Introduction SafetyanalysesapprovedforSt.LucieUnit1(PSL1)assumeaminimumdesignReactorCoolantSystem(RCS)flowrateof355,000gpmandanaverage25~(+7%)ofallsteamgenerator tubesplugged(SGTP).DuringtheSpring1996refueling

overhaul, theestimated numberofadditional steamgenerator tubesthatwillberemovedfromservice(currently inexcessof2000)willlikelyexceedthe254(average) analyseslimit.Toconservatively accommodate thelargernumberofpluggedSGtubes,FloridaPowerandLightCompany(FPL)proposestochangethePSL1Technical Specifications (TS)toreflectsafetyanalysisassumptions of345,000gpmminimumRCSdesignflowrate(basedon30%averageofallsteamgenerator tubesplugged),

andproposesachangeintheReactorProtective SystemRCSLowFlowLimitingSafetySystemSettingfrom>954to>93~~ofdesignreactorcoolantflow.Evaluations toassesstheimpactoftheproposedchangeswereperformed byFPLandSiemens.PowerCorporation-Nuclear Division(SPC).Ithasbeendetermined thattheresultsofthecurrentSmallBreakLossofCoolantAccident(SBLOCA)analysis, whichassumes25~averageSGTP(+74)and355,000gpmreactorcoolantflow,willcontinuetoboundfullpoweroperation withtheproposedamendment forfuelbatchaverageburnupconditions notexceeding 9135Mwd/MTU(7000Effective FullPowerHours(EFPH)inCycle14).Toassureacceptable marginsforfullpoweroperation beyondthispoint,theSBLOCAeventanalysismustbeperformed usingthevaluesofhigherSGTPandreducedflow.Accordingly, theproposedamendment modifiesTS2.1.1tolimitreactorpowerto<904ratedthermalpowerforCycle14operation beyond7000EFPH.2.ProosedTSChanesandBasesCopiesoftheaffectedTSpages,marked-up toshowthechanges,arecontained inAttachment 4tothissubmittal.

a.Pae2-1Secification2.1.1REACTORCORE:Insertanasteriskfollowing THERMALPOWER,andaddthefollowing footnote:

• ForCycle14operation beyoml7000LPPH,THERMALPOWERshallnoterceed90%of2700Megawatts (thermal).

St.LucieUnit.'1DocketNo.50-335ProposedExigentLicenseAmendment ThermalMarinandRCSFlowLimitsL-96-141Attachment 2Page3of16b.ThelimitonthermalpowerforCycle14operation beyond7000EFPHassuresthatcalculated peakfuelcladdingtemperatures duringSBLOCAremainwithin10CFR50.46acceptance criteriafortheentireoperating cycle.Pae2-2FIGURE2.1-1ReactorCoreThermalMarinSafetLimit-Four Reactor.CoolinPumsOeratin:ReplacethisfigureinitsentiretywiththerevisedFIGURE2.1-1showninAttachment 4ofthissubmittal.

c~The"vesselflowlessmeasurement uncertainties" ischangedfrom355,000gpmto345,000gpmbasedon30~averageSGTP.ThethermallimitlinesshowninthisfigurehavebeenrevisedtoreflectthereducedflowusingSPCmethodology.

Thelinesrepresent thelociofpointsofthermalpower,ReactorCoolantSystem(RCS)pressure, andmaximumcoldlegtemperature with.fourreactorcoolantpumpsoperating forwhichtheDeparture fromNucleateBoilingRatio(DNBR)isnolessthantheDNBRlimitforthemostlimitingaxialpowerdistribution showninTSFigureB2.1-1.TheminimumDNBR'limitforsteadystateoperation, normaloperational transients, andanticipated tr'ansients remainsunchanged fromtheexisting, approvedvalueof1.22.Thisvaluecorresponds to95%probability ata954confidence levelthatDNBwillnotoccurandrepresents anacceptable margintoDNBforalloperating conditions.

Pae2-4TABLE2.2-1ReactorProtective Instrumentation TriSetointLimits:(1)ChangetheTRIPSETPOXNTandALLOWABLE VALUESforFUNCTIONAL UNIT3,ReactorCoolantFlow-Low, from>954ofdesignreactorcoolantflowwith4pumpsoperating*

to293%ofdesignreactorcoolantfio>vwith4pumpsoperating*.

RCSflowisdetermined bycalorimetric methodsduringpowerascension testingafterarefueling outage.Theactuallowflowtripsetpointisbasedonthisinferredflowmeasurement andisprocedurally controlled toconsidercalorimetric uncertainties, instrument loopuncertainties, instrument signalnoise,andthespecified designRCSflow.TheproposedLSSSisconsistent withCycle14safetyanalysisassumptions andwillprovideadditional operating margintoprotectagainstunwarranted, spuriouslowflowtripsand/orpre-tripalarms.(2)InFootnote*,changethedesignreactorcoolantflowwith4pumpsoperating from355,000gpmto345,000gpm.The I~~~pSt.LucieUnit1DocketNo.50-335ProposedExigentLicenseAmendment ThermalMarinandRCSFlowLimitsL-96-141Attachment 2Page4of16proposedvalueiscommensurate withtheminimumdesignflowexpectedwith30~SGTP.Id.Pae342-14TABLE3.2-1DNBMARGIN:ChangetheReactorCoolantFlowRatefrom355,000gpmto345,000gpm.

Theproposedvalueiscommensurate withtheminimumdesignflowexpectedwith30>oSGTP~e.Pae5-5DESIGNFEATURESSecification 5.4.2:Modifythedescription ofthereactorcoolantsyst:emVOLUMEtoread:Thetotalwaterandsteamvolumeofthereactorcoolantsystemis11,100+180cubicfeetatanominalT,,of567'F,whennotaccounting forsteamgenerator tubeplugging.

Thisisanadministrative changetoclarifythecondition forwhichthestatedvalueofRCSvolumeisapplicable.

3.GeneralEffectoftheProosedChanesonEventAnalsisThechangesproposedbythislicenseamendment canaffecttheplantsafetyanalysesinthefollowing manner.a.Areduction inRCSflowratehasanadverseeffectonthecalculated Departure fromNucleateBoilingRatio(DNBR).DNBRisadirectindication ofavailable thermalmargin,andareduction inthecalculated minimumDNBRindicates thatthermalmarginforthecorresponding transient hasbeenreduced.b.Areduction inthevalueofthelowflowtripsetpointwillresultinalowerreactorcoreflowrateatthetimeofreactortrip,andcantherebyimpactthecalculated minimumDNBRforcertaintransients.

c.Areduction inRCSflowrateresultsinacorresponding increaseinRCSaveragecoolanttemperature (Tave).AhigherTavecanimpactbothDNBR-related andlossofprimaryinventory typesoftransients.

d.Theremovalofadditional steamgenerator tubesfromservice(plugging) reducestheprimarytosecondary heattransferareainthesteamgenerators.

Thiseffectismostrelevanttotransients involving asuddenreduction intheheatremovalcapability ofthesecondary plant.Inaddition, areduction ofinitialRCSinventory duetosignificant SGTPcanaffect

~~I~St.LucieUnit1DocketNo.50-335ProposedExigentLicenseAmendment ThermalMarinandRCSFlowLimitsL-96-141Attachment 2Page5of16theresultsofborondilutionevents,aswellasthedepthofcoreuncoveryandcalculated peakcontainment pressureresulting fromlossofcoolantaccidents.

4.Evaluation ofUFSAR'hater15EventsAreviewofeventsintheSt.LucieUnit1UpdatedSafetyAnalysisReport(UFSAR)toassesstheimpactfromplantoperation withanincreaseinaverageSGTPto30%(+74),areduction inRCSdesignflowto345,000gpm,andalowflowLSSSof93%ofdesignflowwasperformed'y bothFPLandSPC.SPC'sevaluation, including reanalysis data,isreportedintheEnclosure (EMF-96-135) withthissubmittal, andincludesasummarydisposition withStandardReviewPlan/UFSAR eventcross-reference inTable3.1.Descriptions ofhowtheincreased SGTPandreducedRCSflowhasbeenevaluated toimpactselectedeventsfollow.a.DecreaseinSecondarSideHeat.RemovalLossofExternalLoadLOELTheLossofExternalLoad(LOEL)wasreanalyzed toexaminetheimpactoftheproposedchangesonthecalculated maximumprimaryandsecondary pressures, andtodetermine whethertheexistingpressurelimitof2750psiafortheprimary,and1100psiaforthesecondary wouldbeexceeded.

TheLOELtransient isthelimitingeventinthe"Decrease inHeatRemovalbytheSecondary System"classbecauseofmostrapidreduction ofsecondary heatremovalcapability throughclosureoftheturbinestopvalves.Theassumptions usedinthisanalysisresultinthiseventbeingmoreseverethantheTurbineTrip,LossofCondenser Vacuum,andMainSteamIsolation ValveClosureeventsfromapressurization viewpoint.

FromDNBRconsiderations, thiseventisboundedbytheLossofFlow(LOF)transient.

Sinceareduction ininitialRCSflowisexpectedtoimpactDNB-related eventsinasimilarmanner,itisconcluded thatthiseventwillcontinuetoremainboundedforDNBRbytheLossofFlowevent.Important assumptions usedtomaximizeRCSpressureinthistransient are:(a)positiveModerator Temperature Coefficient

(+7pcm/F)consistent withthemaximumallowedbyTS3.1.1.4,(b)reducedS/Gheattransferareaconsistent withtheproposedtubepluggingvalue,(c)inoperable steamdumpand

~t~IIll1 St.LucieUnit1DocketNo.50-335ProposedExigentLicenseAmendment ThermalMarinandRCSFlowLimitsL-96-141Attachment 2Page6of16bypasssystem,(d)transient initiated byclosureoffastacting(turbinestop)valve,and(e)reactortripbyturbinetripdisabled.

Areduction intheRCSflowhasnodirectimpactonthesystempressurization.

Anincreased S/Gtubeplugginghastheeffectofincreasing theprimarycoolantinsurgeintothepressurizer.

Thisisbecausethereducedprimary-to-secondary heattransferarearesultsinalowerinitialsecondary sidepressure, thusdelayingMainSteamSafetyValve(MSSV)actuation andleadingtoagreaterexpansion oftheRCSfluid.Thiseffectwilltendtoincreaseprimarysyst:empressure.

Resultsofthere-analysis forthiseventindicatethecalculated peakprimarypressuretobe2714psia,belowthe.limitingcriteriaof110'oofdesignpressure(2750psia).Secondary systempressurewasdetermined tobe1031psia,whichislessthanthe1100psiasecondary sideacceptance criteria.

Therefore, itisconcluded thatincreased steamgenerator tubepluggingandtheassociated reduction inRCSflow,hasnoadverseimpactoncompliance withover-pressurization criteriaforthedecreaseinheatremovalbythesecondary systemclassoftransients.

b.DecreaseinReactorCoolantSstemFlowRateEventswithinthiscategoryoftransients areinitiated byamalfunction oftheReactorCoolantPumps(RCP)withtheresultant decreaseincoolantflowcausingadegradation inthecalculated DNBR(closertothelimitof1.22).Twoeventsinthiscategoryareimpactedbytheproposedreduction indesignRCSflowandlowflowtripsetpoint:

LossofReactorCoolantFlow(LOF)andSeizedRCPRotor.(1)LossofReactorCoolantFlowTheLossofFloweventwasevaluated withtheinitialconditions modifiedtoincludetheproposedchanges.Theobjective ofthisevaluation wastodetermine whethertheexistingDNB-LCO(TS3/4.2.5),

inconjunction withtheRPSLowFlowTrip,willpreventtheDNBRlimitof1.22frombeingviolated.

ThiseventisanalyzedonacyclespecificbasisaspartoftheLimitingConditions forOperation (LCO)setpointverification, becauseitisthemostlimitingAnticipated Operational Occurrence (AOO)withrespecttoDNBR.After St.LucieUnit1DocketNo.50-335ProposedExigent,LicenseAmendment ThermalMarinandRCSFlowLimitsL-96-141Attachment 2Page7of16accounting fortheproposedRCSflowreduction, reducedlowflowtripsetpoint, andincreased tubeplugging, thetransient wasevaluated forCycle14reloadbyapplyingdeterministic penalties totheavailable powermargin.Resultsofthisevaluation showareduction intheminimumpowermarginfrom6.8>to1.9%ofratedpower.Theavailable marginconfirmsthattheminimumDNBRisgreaterthanitslimitvalueof1.22.Or,equivalently, theLOFeventinitiated withintheexistingDNBLCOconstraints willnotresultinviolation oftheSpecified Acceptable FuelDesignLimit(SAFDL)forDNBR.(2)SeizedRCPRotorTheseizedrotorevent,isassumedtobeinitiated byaninstantaneous seizureofoneofthereactorcoolantpumpshafts.Becauseoftheverylowprobability associated withthisevent,alimitednumberoffuelrodfailuresarepermitted tooccur.Thiseventwasevaluated toassessthenumberoffuelrodsexpectedtofailasaresultoftheproposedchangestotheRCSflowandthelowflowtripsetpoint.

AdecreaseintheRCSflowandareduction inthelowflowtripsetpointwillresultinlowerDNBRsandahigherpercentage offuelrodfailuresforthisevent.Theresultsoftheanalysisofrecordshowthat,1'.ofthefuelrodswillfail.Theanalysisofrecordforradiological consequences conservatively assumedfuelfailuresof2.54.Themarginavailable inthisanalysis, duetoexcessconservatism inthereactorpowerandRadialPeakingFactor(Fr),.hasbeendetermined tonearlyoffsettheeffectsofthedecreased coolantflowandreducedlowflowtripsetpoint, resulting inanetpowerpenaltyof0.57:.ThesmalldecreaseinDNBRassociated withthe0.57%powerpenaltywillnotcausethefuelrodfailurestoincreasefromthepresentvalueof14tomorethan2.5%valueusedintheradiological

analysis, particularly withthestatistical treatment ofpowerusedintheseizedrotoranalysis.

Therefore, FPLhasconcluded thattheimpactofincreased SGTP,reducedRCSflow,andreducedlowflowtripsetpointonthefuelfailurerateresulting fromtheSeizedRCPRotoraccidentisacceptable.

c.Reactivit andPowerDistribution Anomalies Theeventsinthiscategoryarenotimpactedbythechangeinlowflowtripsetpoint.

OnlythedroppedCEAtransient requiredevaluation duetothereducedRCSflow.

~~St.LucieUnit1DocketNo.50-335ProposedExigentLicenseAmendment ThermalMarinandRCSFlowLimitsL-96-141Attachment 2Page8of16DroedCEAThistransient isexplicitly analyzedeachcycleaspartoftheDNB-LCOsetpointverification.

Thiseventcausesanasymmetry inthecorepowerpeakingdistribution anditsconsequences onDNBRdependonthecycletocyclefuelloadingpatterncharacteristics.

Resultsoftheevaluation performed, afteraccounting fortheproposedchanges,showareduction intheminimumpowermarginfrom8.04to4.6%ofratedpower.Basedontheavailable margin,itisconcluded thattheoccurrence ofaCEAdropevent,afterimplementation oftheproposedchanges,willnotresultinviolation oftheDNBRSAFDL,providedthetransient isinitiated withintheconstraints oftheDNBLCO.d.DecreaseinReactorCoolantInventorEvents(1)LareBreakLOCALBLOCAThiseventwasevaluated toaccountfortheimpactoftheproposedchangesonthepeakcladdingtemperature.

Theeffectsontheblowdownandre-floodphasesofthetransient duetoalowerinitialsecondary pressure(resultofhighertubeplugging) andanincreased coreaveragetemperature (resultoflowerRCSflow)wereestimated toresultinaminorimpactonthecalculated peakcladdingtemperature (PCT),wellwithintheconservatism intheanalysisasdescribed below.Theanalysisofrecordusesaconservative combination ofinitialfuelpelletstoredenergyandaxialpowerprofilestoboundtheentirecycleofoperation.

Additional conservatism liesintheassumption ofamaximumresinterdensityof1.14comparedto0.81%as-builtvalueforCycle14.Theuseofanas-builtresinterdensityisestimated toresultinareduction ininitialfuelaveragetemperature of34FforthecaseoffuelstoredenergynearBOCandatleast16Fforthecaseoffuelstoredenergyrepresenting MOC.Thisamountofconservatism inthefuelstoredenergyrepresents asignificant conservatism inPCT,andtheanalysisofrecordwouldcontinuetoremainbounding.

Additional discussion involving theLBLOCAevaluation isprovidedintheenclosedreport,EMF-96-135.

Itisconcluded that,aLBLOCAinitiated fromplantconditions consistent withtheproposedchanges,willhaveconsequences whichsatisfytherequirements of10CFR50.46(b).

St.LucieUnit1DocketNo.50-335ProposedExigentLicenseAmendment ThermalMarinandRCSFlowLimitsL-96-141Attachment 2Page9of16(2)SmallBreakLOCASBLOCATheSmallBreakLOCAeventforSt.LucieUnit1wasevaluated fortheimpactofthereducedprimarysystemflowandtheincreased S/Gtubeplugginglevel(30:average).

Increased S/Gtubepluggingwillresultinareduction intheinitialRCSinventory whichcouldcauseadeepercoreuncovery.

Also,asmallincreaseintheprimarysystemaveragetemperature duetothelowerRCSflowwilltendtoslowthedepressurization, delayingsafetyinjection.

Theseeffects,however,aresmall.Theresultsofthiseventareinfluenced morebychangestothetop-peaked axialprofiles.

Theanalysisofrecordusesatop-peaked axialprofilefromtheend-of-cycle (EOC)conditions.

AreviewofCycle14axialprofilesshowedthatthemaximumpeakpowerelevation corresponding tothemiddle-of-cycle (MOC)waslowerthanthatusedintheanalysisofrecord.TheaverageburnupoftheMOCaxialprofileswas7000EFPH.Theconservatism intheanalysisduetothisaxialprofile,uptothisburnup,willoffsetanyadverseeffectsduetotheincreased tubeplugginganddecreased RCSflow.Adetermination oftheoffsetting effectsbeyondMOCwasnotpossiblewithoutquantifying theeffectsbyre-analysis.

However,sinceSBLOCAisverysensitive tocorepower,areduction inthereactorthermalpowerto90:ofratedpowerbeyond7000EFPHofoperation isestimated toprovidesufficient margintooffsetanyadverseeffectsoftheproposedchanges.Thisreduction incorethermalpowerisestimated toreducethemassinventory lostoutofthebreak,whichisapproximately twiceaslargeasthereduction ininitialinventory causedbytheincreased tubeplugging.

Also,theprimarysystempressurewilldecreasemorerapidlybecauseofthelowersteamgeneration rateintheprimarysystem.Theanalysisofrecord,therefore, wouldremainbounding.

Additional discussion involving the904powerconstraint isprovidedinSection3.2.6.4oftheenclosedreport,EMF-96-135.

Itisconcluded thatthecurrentSBLOCAanalysiswillboundCycle14operation onlyupto7000EFPH.

~~

St.LucieUnit1DocketNo.50-335ProposedExigentLicenseAmendment ThermalMarinandRCSFlowLimitsL-96-141Attachment 2Page10of16e.Uncontrolled CEAWithdrawal Boththeuncontrolled CEAwithdrawal fromlowpowerandtheCEAwithdrawal initiated fromhighpowerconditions areeventsanalyzedagainstDNBRcriteria.

Themostlimitinganticipated operational occurrence fromtheDNBconsiderations istheLossofFloweventwhichwasevaluated andpreviously discussed inSection4.b(1).Sincetheproposedreduction inRCSflowisexpectedtoaffecttheDNB-related eventsinasimilarmanner,theCEAwithdrawal eventwillcontinuetoremainboundedbytheLossofFlowtransient.

SincetheLOFanalysisresultsareacceptable, it.isconcluded thattheuncontrolled CEAwithdrawal willnotresultinviolation oftheDNBRSAFDL,wheninitiated fromwithintheDNB-LCO.BoronDilutionEventAborondilutioneventcanoccurduringanymodeofplantoperations.

Protection againstviolation ofSAFDL'sforborondilutioneventsinitiated atpowerisprovidedbytheexistingTM/LPtrip,theVariableHighPowerTrip(VHPT)andtheLPDLSSS.Increased S/GtubepluggingwillresultinasmallchangeinRCSfluidvolume(-1.28%).

Thisinturnwillimpactthetimetocriticality determined intheborondilutioneventanalyses.

Thereference analysesfordilutioneventsinitiated fromhotstandbyorhot/coldshutdownconditions atSt.LucieUnit1,showthatmarginexiststotheacceptance criteriainthetime.tocriticality.

SinceMode6onlyconsiders themassinventory inthe,reactorvessel,theincreaseinS/GtubepluggingdoesnotaffectMode6.ForModes2to4,thedecreaseintheRCSinventory wascalculated toreducethetimetocriticality from72.02minutesto71.1minutes.Thistimeisgreaterthantheacceptance criteriaof15minutes.Thetimetocriticality forMode5reducedfrom20.54minutesto20.3minutes,relativetothecriteriaof15minutes.Theborondilutioneventresultsare,therefore, acceptable fortheproposedchanges.g,CEAE'ectionAccidents Acontrolrodejectionaccidentisdefinedasthemechanical failureofacontrolrodmechanism pressurehousingresulting St.LucieUnit1DocketNo.50-335ProposedExigentLicenseAmendment ThermalMarinandRCSFlowLimitsL-96-141Attachment 2Page11of16intheejectionofaCEAanditsdriveshaft.Theconsequence ofthismechanical failureisarapidreactivity insertion andanadversecorepowerdistribution, whichmayresultinlocalized fueldamage.4Increased S/Gtubepluggingwillhavenosignificant effectontheresultsofthistransient becausepredictions offuelfailurearebasedonfuelcenterline meltcriteria(deposited energyinthefuelrod),notonDNBRcriteria.

Therefore,,a reduction inRCSflowproposedhere,willnotimpacttheresultsofthiseventwithrespecttocoredamageoroffsiteradiological doseconsequences.

Inadvertent 0eninofPressurizer PressureReliefValvesAlthoughthiseventisthemostDNB-limiting withinthe"Decrease inReactorCoolantInventory" categoryoftransients, itisboundedbytheLossofFlowevent.SincetheproposedchangeswillnotaffecttherelativebehaviorofDNBRbetweenthetwotransients, thiseventwillcontinuetoremainboundedbytheLossofFlowevent.Theinadvertent PORVopeningisalsooneofthetransients usedinthedetermination ofthelimitingpressurebiastermintheTM/LPequation.

Thisbiastermisdependent onthemaximumrateofchangeofDNBRexperienced duringtheevent,whichforthiscase,isdirectlydependent ontherateofdepressurization.

Sincetheproposedchangesdonot.affectthedepressurization rateinthistransient, itisconcluded thatthereisnoimpactontheexistingTM/LPpressurebias.SteamGenerator TubeRutureSGTRExistinganalysesoftheSGTReventdemonstrate thepotential radiological consequences ofthistransient.

Theseanalyseshaveconcluded thattheassociated radiological releaseisprimarily dependent onthebreakflowrateandthecorresponding primary-to-secondary masstransferduringtheevent.Theradiological releasesweredetermined tobeasmallfractionof10CFR100limits.Thedifferential pressure(primary-to-secondary) acrossthesteamgenerator tubesdetermines iftheflowthroughthebreakischokedornot.Theexistinganalysisofrecordexaminedtheboundingcasewherebreakflowwaschokedbeforereactorscram.Afterreactorscram,thetransient responseisgovernedbytheopeningofsteamdumpandbypassvalves.

St.LucieUnit1DocketNo.50-335ProposedExigentLicenseAmendment ThermalMarinandRCSFlowLimitsL-96-141Attachment 2Page12of16Thepostulated increaseinS/Gtubeplugginglevelwillresultinreducedsecondary sideoperating pressureatSt.LucieUnit1.ThischangecouldresultinslightlylongertimesofchokedflowforanactualSGTR.However,theanalysisofrecordassumeschokedflowconditions duringtheperiodofinterestbeforereactorscram,andtherefore willremainbounding.

Itis,therefore, concluded thattheproposedchangeswillnotalterthesystemresponseandtheresultant potential offsitedoseconsequences fortheSGTRevent.j.IncreaseinHeatRemovalbtheSecondarSstemEventsinthiscategoryareevaluated bycalculating theincreaseinprimarysystemcoolingduetotheparticular eventinitiator.

Noneoftheeventsinthiscategoryareadversely impactedbytheproposedincreaseinsteamgenerator tubepluggingorreducedRCSflowandlowflowtripsetpoint.

Adiscussion oftheindividual transient evaluations follows.(1)ExcessLoadThreeeventswithdifferent initiators arepostulated withthelimitingsub-event beingtheinadvertent openingofallthesteamdumpandbypasssystemvalvesatfullpower.Thisscenariowouldresult,inanapproximate 43.4%increaseinsteammassflowrate.Thiseventhasbeendetermined tobeboundedbytheLossofFloweventforDNBconsiderations andnoneoftheproposedchangeswillsignificantly impacttherelativeDNBRbehaviorbetweenthesetwotransients.

Therefore, noreanalysis ofthiseventwasrequired.

(2)SteamSstemPiinFailuresInsideOutsideContainment SteamSystemPipingFailureeventsareanalyzedtoensurethatanyfuelfailureswhichmightoccurarelimitedtoasmallpercentage ofthefuelinthecore.Theseanalyses, areusedtodetermine whetherfuelfailureswouldresultfromviolation ofeithertheDNBRorfuelcenterline meltSAFDL's.Becausetheinitialcorepowerdistribution hasnotbeenchangedandsincethetimeofminimumDNBR,inthelimitingcase,occursduringaperiodofnaturalcirculation flow,thekeyparameter affecting fuelfailuresisthereturntopowerlevelcausedbyreactivity feedbackfollowing thebreak.Theprimarysystemcooldownfollowing alimitingsteamsystempipingfailureinitiated withincreased steamgenerator tubepluggingandreducedRCSflowwillbeboundedby(nomore St.LucieUnit1DocketNo.50-335ProposedExigentLicenseAmendment.

ThermalMarinandRCSFlowLimitsL-96-141Attachment 2Page13of16severethan)theexistinganalysis.

Thereducedprimarytosecondary heattransferrateacrossthesteamgenerator andthelowerinitialsecondary pressurebothcontribute tomakethisamorebenignevent.Theseeffectsensurethattheexistinganalysisofrecordforsteamsystem.pipingfailureswillremainboundingandpotential off-sitedoseconsequences remainunchanged.

(3)Inadvertent 0eninofaSteamGenerator ReliefAtmoshericDumValveThiseventisnormallyevaluated toassessradiological consequences.

Radiological releasescausedbythiseventwillbelesssevereandlesslikelytooccurafterimplementation oftheproposedchangesbecauseofthelowerinitialsecondary sidepressureresulting fromtheincreased steamgenerator tubeplugginglevel.Theanalysisof.recordassumesconservative Technical Specification limitsfortheprimarytosecondary leakratewhichremainsunchanged.

Therefore, theexistinganalysisofrecordwillremainboundingforthisevent.k.Theimpactoftheproposedchangesonrelevantsetpointanalyseswasalsoevaluated.

ThesetpointanalysesincludetheReactorProtection System(RPS)LocalPowerDensity(LPD)LSSS,LPDLimitingCondition forOperation (LCO),ThermalMargin/Low Pressure(TM/LP)LSSS,andtheDNBLCOforallowable corepowerasafunctionofAxialShapeIndex(ASI).Verification ofthevalidityofthesesetpoints isdiscussed inSection4.0ofEMF-96-135.

5.Evaluation ofOtherSelectedUFSARAnalsesWhilethediscussion inSections3and4focusedontheimpactoftheproposedRCSflowreduction andincreased steamgenerator tubepluggingontheresultsoftheplantUFSARChapter15SafetyAnalysis, acompleteevaluation oftheimpactoftheproposedchangesrequirestheevaluation ofseveraladditional issues.Thesearesummarized below.a.PlantNaturalCirculation CaabilitFPLhasexaminedtheincreased tubepluggingtodetermine ifanyadverseimpactonnaturalcirculation coolingcapability wouldresult.

St.LucieUnit1DocketNo.50-335ProposedExigentLicenseAmendment ThermalMarinandRCSFlowLimitsL-96-141Attachment 2Page14of16Thecalculations performed byFPLinsupportofthecurrentanalysislimitof25:(+7:)tubepluggingshowedthatnaturalcirculation capabilities with18%and324SGTPwereverysimilar,withcoldlegtemperatures differing bylessthan1F(FPLletterL-93-035; 3/19/93insupportofLicenseAmendment 130).Thesimulation wasperformed assumingnooperatoractions,andwithheatremovalbytheSGsafetyvalves.FPLdetermined thatthecooldownratewasdominated byoperation ofthesecondary safetyvalves,andthatincreased SGTPhadnoadverseimpact.Therefore, FPLhasconcluded thattheproposedchangeswillnotpreventtheoccurrence ofnaturalcirculation.

b.PeakContainment Pressurization FollowinLBLOCAorSteamSstemPiinFailurecoLargeBreakLOCAandSteamPipeBreakInsideContainment analysesofrecordwereevaluated todetermine ifthereducedRCSflowand/orincreased tubeplugginglevelwouldcausethecontainment designpressurevaluetobeexceeded.

FortheLBLOCAeventinsidecontainment, thereduction inprimarysystemfluidvolumeavailable forblowdown, ahigherresistance toblowdown, andlesssecondary toprimaryheat.transfercompletely offsettheeffectsfromaslightincreaseinsystemenergyduetothehigherinitialRCSTave.Thepeakpressureintheanalysisofrecordwillremainbounding.

SteamPipingFailuresinsidecontainment werealsoexaminedanditwasconcluded that,afterallowingfortheproposedchanges,nocompromise ofthepressurelimitsoncontainment analysiswouldresult.Increased tubepluggingwillresultinasmallincreaseinthetotalsecondary sidemassinventory, butthattheoverallenergystoredinthefluid(andeventually releasedtocontainment duringthisevent)isnotincreased.

Inaddition, thelowerinitialsecondary pressurewillallowlessblowdown(fromtheintactS/G)priortoMainSteamIsolation Signal(MSIS).AuxiliarFeedwater SstemAFWHihEnerLineBreakTheexistingsystemevaluation fortheAFWsystemidentified thiseventinconjunction withlossofoffsitepowerasthelimitingcondition forplantoperators tobeabletoinitiateauxiliary feedwater flow.Theanalysisforthiseventwasevaluated withrespecttotheincreased averageprimarycoolanttemperature.

Itwasdetermined thatanadditional 637

~v~~St.LucieUnit.1DocketNo.50-335ProposedExigentLicenseAmendment ThermalMarinandRCSFlowLimitsL-96-141Attachment 2Page15of16ibmofinventory wouldbeboiledofffromthesecondary sidereducingthedryouttimefrom650secondsto611.7seconds.Nocredit,wastakenfortheincreased initialsecondary sidemassinventory.

Itisconcluded thatallacceptance criteriawillbesatisfied withincreased steamgenerator tubepluggingandreducedRCSflow.d.LowTemeratureOverressureProtection LTOPAnalsisTheexistingLTOPanalysiswasevaluated todetermine whetherthepostulated increaseinsteamgenerator tubepluggingwouldimpacttheconsequences ofstartingaRCPwiththeplantsecondary sideatahighertemperature thantheprimaryside.Plugginganincreased numberofS/Gtubeswasdetermined toresultinaslightincreaseofthethermaltimeconstantofthesystem,whichforthiseventleadstoaslowerrateofenergyadditiontotheprimaryside.OnlyachangeintheRCPheatoutputorintheinitialcondition ofprimarytosecondary hTcouldchangetheenergydeposited intheprimarysystem,andhence,thepeakpressure.

Therefore, increasing thesteamgenerator averagetubepluggingto30:hasnoadverseimpactonthepressurespikecausedbystartingaRCPpumpunderlowtemperature conditions.

e.OverressureProtection AnalsisInAppendix5AoftheSt.Lucie1UFSAR,ananalysisdocumenting thesizingoftheprimaryandsecondary safetyvalvesispresented.

Theintentofthisanalysis, whichisbasedona"worstcase"lossofloadevent,istosizethesafetyvalves.Thesafetyvalveflowratesarechosensuchthatthepeaksystempressureislessthan110%ofdesign.Theimpactoftheproposedincreaseinsteamgenerator tubepluggingandreducedRCSflowonthelicensing analysisfortheLossofExternalLoadeventwaspreviously discussed (seeSection4.a).Sincethatanalysisconfirmed compliance withthepressurization

criteria, itindirectly verifiedthecontinued validityofthemainsteamsafetyvalvesizinganalysisofreference.

Therefore, itisconcluded thattheproposedchangesdonotrequireanincreaseinmainsteamsafetyvalvecapacitytosatisfytheoverpressurization criteria.

St.LucieUnit1DocketNo.50-335ProposedExigentLicenseAmendment ThermalMarinandRCSFlowLimitsL-96-141Attachment 2Page16of16ImactonSteamGenerator Mechanical LoadsThesteamgenerator inlettemperature corresponding to345,000gpmRCSdesignflowiscalculated tobelessthan604F.Thetemperature valueof604Fissupported bytheS/Gmechanical loadcalculations performed for25>+7>asymmetry tubepluggingcase.Therefore, thereisnoadverseimpactonanyacceptance criteriaforthetubesheetandsteamgenerator tubebundle,andsufficient margintostresslimitswillremainavailable.

6~Conclusion Reactorcorethermalmarginsafetylimitsillustrated inTSFigure2.1-1havebeenadjustedtoaccountfortheproposedvalueofdesignRCSflow,anddefinetheareasofsafeoperation intermsofthermalpower,RCSpressure, andcoldlegtemperature forwhichtheDNBRisnolessthantheMDNBRlimit.TheminimumDNBRlimitfor-steadystateoperation, normaloperational transients, andanticipated transients remainsunchanged fromtheexisting, approvedvalueof1.22.ThevalidityofReactorProtective Instrumentation settingsandtripfunctions inconjunction withrelatedLimitingConditions forOperation hasbeenverifiedtoprovideassurance thatreactorcoredesignlimitsarenotexceededfortheproposedchangeinRCSdesignflow.Theassessments performed ofrelevantsafetyanalysesforSt.LucieUnit1demonstrate thatestablished acceptance criteriaforplantperformance willremainsatisfied duringoperation withtheproposedamendment, whichincludesaderatetog90%ratedthermalpowerforoperation beyond7000EFPHinCycle14.Inaddition, potential radiological consequences determined intheanalysesofrecord,andwhichdemonstrate compliance with10CFR100acceptance criteriawillremainboundingforoperation withthereducedRCSflowandincreased SGTP.Therefore, FPLconcludes thatoperation ofthefacilityinaccordance withthisproposedamendment isacceptable.

))~~~St.LucieUnitIDocketNo.50-335ProposedExigentLicenseAmendment ThermalMarinandRCSFlowLimitsATTACHMENT 3DETERMINATION OFNOSIGNIFICANT HAZARDSCONSIDERATION St.LucieUnit1DocketNo.50-335ProposedExigentLicenseAmendment ThermalMarinandRCSFlowLimitsL-96-141Attachment 3Page1of2DETERMINATION OFNOSIGNIFICANT HAZARDSCONSIDERATION Descritionof'mendment:

Theproposedlicenseamendment changestheTechnical Specifications (TS)byreducingthedesignreactorcoolantflowwithfourreactorcoolantpumpsoperating from355,000gpmto345,000gpm(TABLE2.2-1andTABLE3.2-1),revisingthereactorcorethermalmarginsafetylimitsshowninFIGURE2.1-1,andmodifying thereactorcoolantsystemtotalwaterandsteamvolumedescribed indesignfeaturessection5.4.2.Theamendment alsoreducesthereactorcoolantlowflowtripfunctionLimitingSafetySystemSetting(LSSS)from>95%toh93%ofdesignreactorcoolantflow.Finally,TS2.1.1ismodifiedtorestrictreactorpowertoS904ratedthermalpowerforoperation beyond'iddle ofCycle14.Therevisions aremadetosupportchangesinthesafetyanalyseswhichaccommodate alargernumberofpluggedsteamgenerator tubesforOperating Cycle14.Pursuantto10CFR50.92,adetermination maybemadethataproposedlicenseamendment involvesnosignificant hazardsconsideration ifoperation ofthefacilityinaccordance withtheproposedamendment wouldnot:(1)involveasignificant increaseintheprobability orconsequences ofanaccidentpreviously evaluated; or(2)createthepossibility ofanewordifferent kindofaccidentfromanyaccidentpreviously evaluated; or(3)involveasignificant reduction inamarginofsafety.Eachstandardisdiscussed asfollows:(1)Operation ofthefacilityinaccordance withtheproposedamendment wouldnotinvolveasignificant increaseintheprobability orconsequences ofanaccidentpreviously evaluated.

Theproposedamendment definesreactorcorethermalmarginsafetylimitsforareducedvalueofdesignreactorcoolantflow,andestablishes arevisedLimitingSafetySystemSetting(LSSS)fortheprotective systemlowflowtrip.Ascoreprotection variables, theselimitingparameters arenotaccidentinitiators anddonotaffectthefrequency ofoccurrence ofpreviously analyzedtransients.

Thedesignfeatures'otal waterandsteamvolumerevisionaccountsforsteamgenerator tubepluggingandissimplyadministrative innature.Evaluations performed toassesstheimpactoftheproposedamendment concludethat,whenconsidering aunitderateto90>ratedthermalpowerforoperation beyond7000EFPHinCycle14asrequiredbytheproposedchangetoTS2.1.1,thepotential radiological consequences ofpreviously analyzed St.LucieUnit1Docket,No.50-335ProposedExigentLicenseAmendment

'hermalMarinandRCSFlowLimitsL-96-141Attachment 3Page2of2transients willconservatively remainwithinestablished acceptance criteria.

Therefore, operation ofthefacilityinaccordance withthisamendment wouldnotinvolveasignificant.

increaseintheprobability ortheconsequences ofanyaccidentpreviously evaluated.

(2)Operation ofthefacilityinaccordance withtheproposedamendment wouldnotcreatethepossibility ofanewordifferent kindofaccidentfromanyaccidentpreviously evaluated.

Theproposedamendment reviseslimitingparameters toassuresafeoperation commensurate withtheimpactofsteamgenerator tubeplugging, andwillnotchangethemodesofoperation definedinthefacilitylicense.Theanalysisoftransients associated withsteamgenerator failuresarepartofthedesignandlicensing bases.Therefore, operation ofthefacilityinaccordance with.theproposedamendment wouldnotcreatethepossibility ofanewordifferent kindofaccidentfromanyaccidentpreviously evaluated.

t3)Operation ofthefacilityinaccordance withtheproposedamendment wouldnotinvolveasignificant reduction inamarginofsafety.Theproposedamendment allowsfullpoweroperation atanRCSflowcommensurate with30%(average) steamgenerator tubepluggingforCycle14fuelbatchaverageburnupconditions corresponding tomid-cycle.

Foroperation beyondmid-cycle, reactorpowerwillberestricted to<90%ratedthermalpower.Anevaluation oflimitingeventstoestablished acceptance criteriaforSpecified Acceptable FuelDesignLimits(SAFDL),primaryandsecondary overpressurization transients, 10CFR50.46(b)emergency corecoolingsystemsacceptance

criteria, peakcontainment

pressure, potential radiation doseduringaccidents, andtoTSLimitingConditions forOperation hasbeencompleted insupportofthisamendment request.Theevaluation concludes, whenconsidering theproposedLSSSfortheLowFlowtrip,thataconservative margintoacceptable limitsremainsavailable.

Therefore, operation ofthefacilityinaccordance withthisproposedamendment wouldnot.involveasignificant reduction inamarginofsafety.Basedontheabovediscussion andthesupporting evaluation oftechnical specification changes,FPLhasdetermined thattheproposedlicenseamendment involvesnosignificant hazardsconsideration.