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{{#Wiki_filter:CATEGORYleREGULATORYINFORMATIONDISTRIBUTIONSYSTEM(RIDS)ACCESSIONNBR:9901270103DOC.DATE:99/01/20NOTARIZED:NOFACIL:50-335St.LuciePlant,Unit1,FloridaPower&LightCo.AUTH.NAMEAUTHORAFFILIATIONFREHAFER,K.W.FloridaPower&LightCo.STALL,J.A.FloridaPower&.LightCo.RECIP.NAMERECIPIENTAFFILIATIONDOCKET¹05000335
{{#Wiki_filter:CATEGORYleREGULATORY INFORMATION DISTRIBUTION SYSTEM(RIDS)ACCESSION NBR:9901270103 DOC.DATE:
99/01/20NOTARIZED:
NOFACIL:50-335 St.LuciePlant,Unit1,FloridaPower&LightCo.AUTH.NAMEAUTHORAFFILIATION FREHAFER,K.W.
FloridaPower&LightCo.STALL,J.A.
FloridaPower&.LightCo.RECIP.NAME RECIPIENT AFFILIATION DOCKET¹05000335


==SUBJECT:==
==SUBJECT:==
LER98-009-00:op981223,notedthatfacilityoperatedoutsideofdesignbasis.Causedbynon-conservativeMSLBanalysisinputs.WillreviewSRcomponentdifferencesbetweenunits&willre-baselineLTOPanalysis.With990120ltr.DISTRIBUTIONCODE:IE22TCOPIESRECEIVED:LTRIENCLiSIZE:TITLE:50.73/50.9LicenseeEventReport(LER),IncidentRpt,etc.NOTES:RECIPIENTIDCODE/NAMEPD2-3PD'NTERNAL:ACRSAEOD/SPD/RRABNRR/DE/ECGBNRR/DE/EMEBNRR/DRCH/HOHBNRR/DRPM/PECBRES/DET/EIBEXTERNAL:LSTLOBBYWARDNOACPOORE,W.NRCPDRCOPIESLTTRENCL111111111111111111111,1RECIPIENTIDCODE/NAMEGLEAVES,WAEODCENTRDEBNRR/DRCH/HICBNRR/DRCH/HQMBNRR/DSSA/SPLBRGN2FILE01LITCOBRYCE,JHNOACQUEENER,DSNUDOCSFULLTXTCOPIESLTTRENCL11221111111'1111111111CNOTETOALL"RIDS"RECIPIENTS:PLEASEHELPUSTOREDUCEWASTE.TOHAVEYOURNAMEORORGANIZATIONREMOVEDFROMDISTRIBUTIONLISTSOP.REDUC-THENUMBER.OFCOPIESRECEIVEDBY-OUORYOURORGANZATION,CONTACTTHEDOCUMENTCONTRO'ESK(DCD)ONEXTENSION415-2083FULLTEXTCONVERSIONREQUIREDTOTALNUMBEROFCOPIESREQUIRED:LTTR23ENCL23  
LER98-009-00:op 981223,noted thatfacilityoperatedoutsideofdesignbasis.Causedbynon-conservative MSLBanalysisinputs.WillreviewSRcomponent differences betweenunits&willre-baseline LTOPanalysis.
With990120ltr.DISTRIBUTION CODE:IE22TCOPIESRECEIVED:
LTRIENCLiSIZE:TITLE:50.73/50.9 LicenseeEventReport(LER),IncidentRpt,etc.NOTES:RECIPIENT IDCODE/NAME PD2-3PD'NTERNAL:
ACRSAEOD/SPD/RRAB NRR/DE/ECGB NRR/DE/EMEB NRR/DRCH/HOHB NRR/DRPM/PECB RES/DET/EIB EXTERNAL:
LSTLOBBYWARDNOACPOORE,W.NRCPDRCOPIESLTTRENCL111111111111111111111,1RECIPIENT IDCODE/NAME GLEAVES,W AEODCENTRDEBNRR/DRCH/HICB NRR/DRCH/HQMB NRR/DSSA/SPLB RGN2FILE01LITCOBRYCE,JHNOACQUEENER,DS NUDOCSFULLTXTCOPIESLTTRENCL11221111111'1111111111CNOTETOALL"RIDS"RECIPIENTS:
PLEASEHELPUSTOREDUCEWASTE.TOHAVEYOURNAMEORORGANIZATION REMOVEDFROMDISTRIBUTION LISTSOP.REDUC-THENUMBER.OF COPIESRECEIVEDBY-OUORYOURORGANZATION,CONTACTTHEDOCUMENTCONTRO'ESK (DCD)ONEXTENSION 415-2083FULLTEXTCONVERSION REQUIREDTOTALNUMBEROFCOPIESREQUIRED:
LTTR23ENCL23  


FloridaPower5LightCompany.6351S.OceanDrive,JensenBeach,FL34957January20,1999L-99-01210CFR550.73U.S.NuclearRegulatoryCommissionAttn:DocumentControlDeskWashington,D.C.20555Re:St.LucieUnit1DocketNo.50-335ReportableEvent:1998-009-00DateofEvent:December23,1998Non-ConservativeMSLBAnalysisInputsResultin0erationofFacilitOutsideDesinBasesTheattachedLicenseeEventReport1998-009isbeingsubmittedpursuanttotherequirementsof10CFRg50.73toprovidenotificationofthesubjectevent.Verytrulyyours,J.A.StallVicePresidentSt.LucieNuclearPlantJAS/EJW/KWFAttachmentcc:RegionalAdministrator,USNRCRegionIISeniorResidentInspector,USNRC,St.LucieNuclearPlant'ir'ir0i270i03'rr'ir0i20PDRADQCK05000335SPDRanFPLGroupcompany NRCFORM366{6-1996)LtCENSEEEVENTREPORT(LER)(Seereverseforrequirednumberofdigits/charactersforeachblock)EslimatedburdenperresponsetocomplywiththismandatoryInforrnagonco!lectionroquest:50hrs.Roportodlossonslearnedaroincorporatedintotholicensingprocessandfodbacktoindustry.ForwardcommentsregardingburdenestimatetotheRecordsManagementBranch{TAF33)U.S.Roc)earRegulatoryCommission,Washington,DC2t$5$4001,andlothePaperwrxkReductionProioct(31500104),OfficeofManagementandBudgol,Washington.Dc20503.IfaninformationcollectiondoesnotdisplayacurrentlyvalidOMBcontrolnumber,theNRCmaynotconductorsponsor,andapersonhrnolrequiredlorespondto,thoInformationcoltecgon.U.S.NUCLEARREGULATORYCOMMISSIONAPPROVEDBYOMBNO.3150-0104EXPIRES0613012001FACILITYNAME(1)St.LucieUnit1DOCKETNUMBER{2)05000335PAGE(3)Page1of8TITLE(4)Non-ConservativeMSLBAnalysisInputsResultinOperationofFacilityOutsideDesignBasesMONTHDAYEVENTDATE(5LERNUMBER6)SEQUENTIALREVISIONNUMBERNUMBERMONTHDAYREPORTDATE7IFACIUTYNAMEOTHERFACILITIESINVOLVED6OOCKETNUMBER1'219981998-009-00011999FACIUTTNAMEOOCKETNUMBOlOPERATINGMODE(9)20.2201(b)20.2203(a){2){v)50.73(a)(2)(i)50.73{a){2)(viii)THISREPORTISSUBMITTEDPURSUANTTOTHEREQUIREMENTSOF10CFREt(Checkonoormore){11)POWERLEVEL(10)10020.2203(0)(1)20.2203(a)(2)(i)20.2203(a)(2)(ii)20.2203(a)(2)(iii)20.2203(a)(2)(iv)20.2203(a)(3)(i)20,2203(o)(3)(ii)20.2203(a)(4)50.36{c){1)50.36(c)(2)X50.73{a)(2){ii)50.73(a)(2)(iii)50.73(a)(2)(iv)50.73(a)(2){v)50.73(a)(2)(vii)50.73(aw2)(x)73.71OTHERSpecifyinAbstractbeloworInNRCForm36SAHAMELICENSEECONTACTFORTHISLERl12)TELEPHONENUMBERSnorudeAresCode)KennethWFrehafer,LicensingEngineer(561)467-7748COMPLETEONELINEFOREACHCOMPONENTFAILUREDESCRIBEDINTHISREPORT13CAUSESYSTEMCOMPONENTMANUFACTURERREPORTABLETOEPIXCAUSESYSTEMCOMPONENTMANUFACTURERREPORTABLETOEPIXBNHN/AN/ANOSUPPLEMENTALREPORTEXPECTED(14)YES{IfYes,completeEXPECTEDSUBMISSIONDATE).XNOEXPECTEDSUBMISSIONDATE{15)MONTHDAYABSTRACT/Limitto1400spaces,i.o.,opproximately15single-spacedtypewrittenlinesi(16)OnDecember23,1998,St.LucieengineeringpersonneldeterminedthatthedraftresultsofaUnit1mainsteamlinebreakcontainmentre-analysisindicateanunexpectedhigherpeakcontainmentpressureof55.946psig.TheUnit1containmentdesignpressureis44psig.Thedifferenceinthere-analysisvalueandtheoriginalcontainmentpeakpressurevalue"isattributedtosomenon-conservativeassumptionsintheoriginalanalysis.Themostsignificantassumptionswerefeedwaterflow,feedwaterisolation,andinitialcontainmentpressure.Thenon-conservatismidentifiedisintheinputdataoriginallyusedtoperformtheanalysis.St.LuciedeterminedthatcontainmentremainsoperablewithanoperabilityassessmentperformedpursuanttoGenericLetter91-18.LongtermcorrectiveactionsincludereviewofsafetyrelatedcomponentdifferencesbetweenUnits1and2,re-baseliningthelowtemperatureoverpressureanalysis,andeitherperformmodificationsor.changethelicensinganddesignbasisoftheMSLBpeakcontainmentpressureanalysis.NRCFOAM306IS.1999)
FloridaPower5LightCompany.6351S.OceanDrive,JensenBeach,FL34957January20,1999L-99-01210CFR550.73U.S.NuclearRegulatory Commission Attn:DocumentControlDeskWashington, D.C.20555Re:St.LucieUnit1DocketNo.50-335Reportable Event:1998-009-00 DateofEvent:December23,1998Non-Conservative MSLBAnalysisInputsResultin0erationofFacilit OutsideDesinBasesTheattachedLicenseeEventReport1998-009isbeingsubmitted pursuanttotherequirements of10CFRg50.73toprovidenotification ofthesubjectevent.Verytrulyyours,J.A.StallVicePresident St.LucieNuclearPlantJAS/EJW/KWF Attachment cc:RegionalAdministrator, USNRCRegionIISeniorResidentInspector, USNRC,St.LucieNuclearPlant'ir'ir0i270i03
NRCFORM366A(6-1888)LICENSEEEVENTREPORT(LER)TEXTCONTINUATIONU.S.NUCLEARREGULATORYCOMMISSION,FACILITYNAME(1)St.LucieUnit1OOCKETNUMBER(2)05000335LERNUMBER(6)SEQUENTIALREVISIONNUMBERNUMBER1998-009-00PAGE(3)Page2of8TEXTllfmorespeceisrequired,useedditionelcopiesofNRCForm366AJ(17)DescriptionofEventOnDecember23,1998,St.LucieUnit1wasinMode1at100percentreactorpower.AfterreviewingadraftUnit1MainSteamLineBreak{MSLB),Containmentre-analysis,St.LucieEngineeringconcludedthatthedraftanalysisresultsindicatedanunexpectedhigherpeakcontainmentpressureof55.946psig.TheUnit1containmentdesignpressureis44psig.Thedraftcalculation,CENP007-ST98-C-012,"St.LucieUnit1ContainmentMSLBMassandEnergyandPressure/TemperatureResponseAnalysis,"wasperformedbyABBandwastransmittedbyABB-CEletterST-98-763forFPLtoreviewandcomment.Thedifferenceinthere-analysisvalueandtheoriginalcontainmentpeakpressurevalueisattributedtosomenon-conservativeassumptionsintheoriginalanalysis.Themostsignificantassumptionswerefeedwaterflow,feedwaterisolation,andinitialcontainmentpressure.Thenon-conservatismidentifiedisintheinputdataoriginallyusedtoperformtheanalysis.ThisconditionwasreportedtotheNRCviatheemergencynotificationsystem(ENS)asanon-emergencyreportpursuantto10CFR50.72(b)(1)(ii)onDecember23,1998.Engineeringperformedanoperabilityassessmentinaccordance.withGenericLetter91-18anddeterminedthatcontainmentremainsoperable.LongtermcorrectiveactionsarebeingformulatedtoeitherimplementchangestorestoretheMSLBcontainmentanalysisresultsorchangetheMSLBcontainmentanalysislicensingbasis.CauseofEventThecauseforthehigherpeakpressureinthere-analyzedMSLBeventisthatnon-conservativeassumptionswereusedintheoriginalanalysisofrecord.TheoriginalMSLBanalysisofrecordwasdevelopedjointlybetweenCombustionEngineering(massenergyinput)andEBASCO(containmentperformance).Thisanalysisconsideredaspectrumofbreaksizes,initialpowerlevels,andsinglefailures.Themostsignificantnon-conservativeinputassumptionsdealtwithfeedwaterflow,feedwaterisolation,andinitialcontainmentpressure.Thisconditionwasnotpreviouslyidentifiedbecause,asdiscussedbelow,aformalre-analysisoftheMSLB'containmentresponsewasneverperformed.SubsequentsensitivitystudiesagainsttheoriginalMSLBcontainmentresponseanalysisofrecordwereperformedduringtheSt.LucieUnit1stretchpoweranalyses.Additionally,themorerecentSteamGeneratorReplacementproject(SGRp)didnotincludeare-baselineoftheoriginalMSLBcontainmentresponseanalysisofrecord.Replacementsteamgenerators(RSGs)wereinstalledduringtheFall1997Unit1refuelingoutage.TheSGRPdidnotincludeare-baselineoftheaffectedUFSARaccidentanalyses.Theimpactstoexistinganalyses,includingMSLB,wereevaluatedpursuantto10CFR50.59.Theevaluationsaddressedpotentialimpactsofcriticalparameterchangesontheanalysesofrecord.Inallcases,theRSGimpactsoncriticalparameterswereevaluatedasbeingboundedbytheanalysisofrecord,butdidnotidentifythelatentnon-conservatismsintheoriginalMSLBinsidecontainmentanalysis.BecausetheRSGs'hangesrepresentedcompetingeffectsontheMSLBanalysis,acalculationwasperformedbyFramatoneTechnologiesInc.(FTI)toquantifythenetNRCFORM388A(8.1888)  
'rr'ir0i20 PDRADQCK05000335SPDRanFPLGroupcompany NRCFORM366{6-1996)LtCENSEEEVENTREPORT(LER)(Seereverseforrequirednumberofdigits/characters foreachblock)Eslimated burdenperresponsetocomplywiththismandatory Inforrnagon co!lection roquest:50hrs.Roportodlossonslearnedaroincorporated intotholicensing processandfodbacktoindustry.
,1 NRCFORM366A(6-1998)LICENSEEEVENTREPORT(LER)TEXTCONTINUATIONU.S.NUCLEARREGULATORYCOMMISSION.FACILITYNAMEI1)St.LucieUnit1DOCKETNUMBER2)05000335LERNUMBERIS)SEQUENTIAlREVISIONNUMBERNUMBER1998-009-00PAGEI3)Page3of8TEXT/Ifmorespaceisrequired,useadditionalcopiesofNRCFarm3MA/I17)CauseofEvent(cont'd)impactontheanalysisofrecord.Themost,significantcompensatingeffectwasfromanintegralsteamlinefloworifice.Theorificewasdesignedtoreducetheeffectivebreaksize.ThisorificewasmorethansufficienttooffsettheotherSGRPchanges(i.e.,higheroperatingpressure/temperature)thatadverselyimpacttheMSLBanalysis).Therefore,theoriginalMSLBanalysisremainedboundingfortheRSGs.Engineeringconductedself-assessmentreviewsofmotoroperatedvalves(MOVs)inpreparationforanNRCauditoftheGL89-10PrograminOctober1997.DuringreviewoftheMFIVsconcernswereidentifiedwithrespect,tofeedwaterassumptionsusedintheoriginalMSLBanalysis.Specifically,thefeedwaterflowisolationwasassumedasa60-secondlinearramp.ActualvalvecharacteristicsfortheMPIVsweremoreconsistentwithastepchangeinflowat60seconds.Additionally,theanalysisdidnotappeartoconsiderblowdownofwaterremaininginthefeedwaterpipingafterMFIVactuation.Also,theoriginalassumptionsfortheflowsplitbetweenthefaultedandunfaultedgeneratorwereindetermanentandpotentiallynon-conservative.Theeffectoftheseassumptionscouldmeanthattheactualflowishigherthanthatassumedintheanalysis.BecausetheMSLBanalysisofrecordhadbeenaugmentedbythePTIcalculationsperformedfortheSGRP,theseeffectsneededtobeevaluatedinadditiontotheRSGeffects.TheSGRPwasrequestedtoperformadditionalsensitivitiestoensurethattheimpactofthenewlydiscoveredfeedwaterassumptionconcernsremainedboundedbytheoriginalMSLBanalysis.Are-analysisoftheFTIcalculationwasperformed,anditwasconcludedthatsufficientmarginfromthesteamlineorificesremainedtoaccommodatethenewfeedwaterflowassumptions.Basedonthisevaluation,allevaluatedeffectsremainedboundedbytheoriginalMSLBanalysisofrecord,andnooperabilityordesignconcernsexisted.Althoughnotrequired,adecisionwasmadeatthistimetore-baselinetheMSLBanalysistofacilitatefutureoperabilityandmodificationevaluations.ThenewanalysiswascompetitivelybidandacontractawardedtoABB-CE.ItwasrecognizedthatinputstotheanalysiswouldneedtoberefinedandsuppliedbyFPLinorderforthereanalysistoremainboundedbytheoriginalUPSARanalysis.Specifically,thefeedwaterflowwouldneedtobemodeledtoevaluatetheactualfeedwaterflowsexpectedandremovethesimplifyingassumptions.FPLandABB-CEhavebeenworkingcloselytorefinetheinputs.However,duringtheprojectseveraladditionalnon-conservativeassumptionsintheoriginalanalysiswereidentifiedwhichcouldnotbejustifiedforthereanalysis.Themostsignificantoftheseare:(1)initialcontainmentpressurewasassumedas0psiginsteadof2.4psigasallowedbytechnicalspecifications;and(2)actualflowtothefaultedsteamgeneratorcouldbehigherthanthetwicenormalfeedwaterflowassumedintheoriginalanalysisduetothepumpsbeingfurtheroutonthepumpcurve.Thesenon-conservativeinputsresultedinthehigherpeakpressuresreportedbythisLER.NRCFORM3BBAIB.1888)
Forwardcommentsregarding burdenestimatetotheRecordsManagement Branch{TAF33)U.S.Roc)earRegulatory Commission, Washington, DC2t$5$4001,andlothePaperwrxk Reduction Proioct(31500104),
NRCFOAM366A(6.1998)~FACILITYNAME(1)St.LucieUnit1LICENSEEEVENTREPORT(LER)TEXTCONTINUATIONDOCKETNUMBER(2)05000335U.S.NUCLEARREGULATORYCOMMISSIONLERNUMBER(6)PAGE(3)SEQUENTIALREVISIONNUMBERNUMBERPage4of8TEXT(Ifmorospaceisrequired,useadditionalcopiesofNRCForm366Ai(17)1998-009-00CauseofEvent(cont'd)AnalysesRe-BaseLiningTheimpactofthelatentnon-conservatismsintheoriginalMSLBinsidecontainmentanalysiswasnotrealizeduntilacompletere-analysiswasperformed.Onepotentialgenericimplicationwouldbeforanyotheranalysesthathavenotbeenre-baselined,butratherevaluatedonanindividualchangebasis.St.Luciereviewedapplicableanalyseswiththefollowingresults.Thefuelanalysesarere-analyzedforeachfuelcycle.TheLOCAcontainmentanalysiswasre-analyzedin1993.OnlytheLowTemperatureOverpressure(LTOp)analysiswasidentifiedasnothavingbeenre-runsinceoriginallicense.TheLTOPanalysisiscurrentlybeingre-baselined.Therefore,allexistinganalysesofrecordhaveeitherbeenorarebeingbase-lined.Theuseofnon-conservativeinputsduringthedevelopmentofanynewfutureanalysesisprecludedbyexistingengineeringprocedures.ProceduralrequirementsensurethatinputstransmittedtoA/EareindependentlyverifiedpriortousebytheA/E.ThedesignoftheUnit1andUnit2mainfeedwaterisolationvalves(MFIVs)aresignificantlydifferent.TheclosuretimesforUnit2areapproximatelyonetenththatforUnit1.However,thecontainmentdesignandotherparameterssignificanttotheMSLBeventareessentiallyidentical.Basedonthisobservation,anothergenericcorrectiveactionwillbetoidentifyanysimilarsignificantdifferencesinsafetyrelatedsystemsandcomponentsbetweenthetwounitsanddetermineiftheyhavebeenadequate'lyreflectedintheanalyses.TheSt.LucieUnit2MSLBcontainmentanalysisdoesnotcontainthesesamenon-conservativeinputdataassumptionsinitsanalysis.Therefore,thisconditionisnotapplicablet'oUnit2.AnalysisofEventThedraftresultsoftheUnit1containmentMSLBmassandenergyandpressureandtemperatureresponseanalysisdonotmeetthemaximumcontainmentpressuredesigncriteriaof44psig.Basedonthedraftdocument,aconditionwasdiscoveredduringplantoperationthatresultsinthenuclearpowerplant,St.LucieUnit1,beinginaconditionthatisoutsidethedesignbasisoftheplant.Asaresult,thisconditionwasreportedasanon-emergencyreportunder10CFR50.72(b)(1)(ii)(B),"Anyeventorconditionduringoperationthatresultsinthenuclearpowerplantbeing:'Znaconditionthatisoutsidethedesignbasisoftheplant.'"Basedonthistypeofreport,theLicenseeisrequiredtosubmitanLERwithin30days.TheLERcomplieswith10CFR50.73(a)(2)(ii)(B)forreportingaconditionthatisoutsidethedesignbasisoftheplant.AnalysisofSafetySignificanceIThedraftMSLBcontainmentanalysiswassubsequentlyfinalizedandissuedtoSt.Lucie.Allconclusionsinthissectionarebasedonthefinalanalysisresults.TheresultsoftheMSLBcontainmentanalysisdonotaffecttheTechnicalSpecificationNRCFORM388A(8.1998)
OfficeofManagement andBudgol,Washington.
NRCFORM366A(6-1998)LICENSEEEVENTREPORT(LER)TEXTCONTINUATIONU.S.NUCLEARREGULATORYCOMMISSION~FACILITYNAME(1)St.LucieUnit1OOCKETNUMBER2)05000335LERNUMBER(6)SEQUENTIALREVISIONNUMBERNUMBER1998-009-00PAGE(3)Page5of8TEXT(Ifmorespaceisrequired,useadditionalcopiesoffVRCForm3MA)(17)AnalysisofSafetySignificance(cont'd)operabilityofthecontainmentorrelatedsystems.Specifically,TechnicalSpecificationoperabilityforTS3/4.6.1.2,CONTAINMENTLEAKAGE,andTS3/4.6.1.6,CONTAINMENTVESSELSTRUCTURALINTEGRITY,arebasedonapeakcontainmentpressureof39.6psigforthelimitingdesignbasisLOCA,nottheMSLB.DuringaMSLBeventthereisarelativelyminorreleaseofradioactivityintothecontainment.Also-notethatinthemorelimitingcaseforoff-sitedose,theMSLBisassumedtooccuroutsidethecontainmentwherethereisadirectpathtotheenvironment.Therefore,thelicensingbasisforthecontainmentoperabilityistheLOCA,nottheMSLB.Asstatedinthepreviousparagraph,thedefinitionofcontainmentoperabilityisnotbasedontheMSLBanalysis.However,thefunctionofthissafetyrelatedstructurecanstillbeshownnottobecompromisedforthere-analyzedMSLBevent.Althoughthecalculatedhigherevaluatedpeakpressureisclosertotheultimatefailureofthecontainment,significantmarginabove56psigremains.TheSt.LucieIndividualPlantExamination(IPE)submittalestimatesacontainmentfailurepressureof95pslg.AbestestimatecasewasalsoperformedbyABB-CE.Thisbestestimatecaseconsideredmorerealisticplantassumptionsinlieuofthemoreconservativedesignbasisassumptions.Specifically,themainfeedregulatingvalves(MFRVs)areassumedtoremainintheirpre-accidentpositionandbothtrainsofemergencycorecoolingsystems(ECCS)areassumedtobeoperable.Thedesignbasiscaseconservativelyandnon-mechanisticallyassumesthatbothMFRVsgofullyopenatthebeginningoftheaccident.Thisresultsinamuchlargerinflowoffeedwatertothefaultedgeneratorthanwouldactuallyoccur.ThebestestimateassumptionoftheMFRVsremainingintheirpre-accidentconditionisstillconservativeinthatthemostlikelyresponsetothebreakwouldbefortheMFRVstoclosedowninresponsetogeneratorswell.ThebestestimateassumptionthatbothtrainsofECCSwouldbeavailabledoesnotmeetdesignbasisrequirementsforsinglefailure,butisreasonablefortheevaluatedscenario.ThemostprobablemeansofacompletelossofoneECCStrain(containmentsprayandcoolers)wouldrequireaLOOPandsubsequentemergencydieselgeneratorfailure.BecauseaLOOPwouldgreatlyreducethepeakpressureasaresultofthereactorcoolantpumps(RCPs)andmainfeedwaterpumpstripping,aLOOPscenarioisnotlimitingforthisaccident.Therefore,theonlyapplicablepostulatedfailureofECCStrainswouldinvolveasingleECCScomponent.Thesearesafetyrelatedcomponentsofhighreliabilitythatareextensivelytestedandmaintained.Thebestestimatecaseresultsinapeakcontainmentpressureof43.339psig,whichisbelowthecurrentUFSARdesignpressureof44psig.AlthoughthebestestimatecaseassumesnormalMFRVoperationandthatbothtrainsofECCSareavailable,operat'ingconstraintsassociatedwiththeseparametersarenotimposedbytheassessment.TechnicalSpecificationoperabilityisbasedontheLOCAeventandnottheMSLBevent.SignificantmarginexistsbetweenthepeakcalculatedMSLBpressureandanticipatedfailureofthecontainment.Thebestestimatecasedemonstratesthatunderconditionsthatwouldnormallybeexpected,thepeakpressurefromapostulatedMSLBremainsbelowdesign.NRCFORM368AI9.1998)
Dc20503.Ifaninformation collection doesnotdisplayacurrently validOMBcontrolnumber,theNRCmaynotconductorsponsor,andapersonhrnolrequiredlorespondto,thoInformation coltecgon.
NRCFORM366AIB-)998)LICENSEEEVENTREPORT(LER)TEXTCONTINUATIONU.S.NUCLEARREGULATORYCOMMISSION'FACIUTYNAMEI1)St.LucieUnit1DocKETNUMBERI2)05000335LERNUMBERI6)SEQUENTIALREVISIONNUMBERNUMBER1998-009-00PAGEI3)Page6of8TEXT/Ifmorespaceisrequired,useadditionalcopiesofNRCForm366AJI17)AnalysisofSafetySignificance(cont'd)St.LucieUnit1UFSARSection6.2.1.1de'scribesthedesignbasesforcontainment.ThecontainmentvesselisdesignedinaccordancewiththeASMECodeSectionIII,ClassMC.Themaximuminternalpressure,asdefinedinArticleNE-3112ofthecode,is44psig.ThisvalueisdocumentedinSection6.2.1.2oftheUnit1UFSAR.ThisvalueisalsodccumentedintheUnit1TechnicalSpecificationdesignfeatures,section5.2.2.DuetothelargeinventorydesignsteamgeneratorsofCEdesignedplants,theMSLBeventtypicallyproducesthepeakcontainmentpressureandtemperature.However,UFSARSection6.2.1.1.bnotesthattheequipmentsurfacetemperatureislaggedandwillgenerallynotexperiencetheelevatedtemperaturesresultingfromapuresteamblowdownresponse(MSLB).Assuch,forthetemperatureresponse,theLOCAeventisboundingandestablishestheenvironmentalqualificationcriteriaandtemperaturelimitations,asdescribedbelow.TheMSLBcontainmentre-analysispeakcontainmentpressurevalueof55.946psigistheparameterevaluatedinthisLER.ContainmentvesselfailureischaracterizedintheSt.LucieUnits1and2IPEsubmittaldatedDecember1993.Specifically,AppendixG,ContainmentFailurePressureCharacterization,providesanassessmentofcontainmentperformancebasedonthemethodologyofNUREG/CR-2442.Thisassessmentestimatesafailurepressureof95psigfortheSt.LucieUnit1and2containmentvessels.Thus,aMSLBcontainmentresponseanalysispeakpressureof55.946psigisboundedbytheestimatedfailurepressureof95psig.ItisnotedthattheLOCAcontainmentanalysiswasupdatedfromtheoriginalcontainmentanalysisforbothSt.LucieUnits1and2in1993andisdocumentedintherespectiveUFSARs.TheMSLBcontainmentre-analysispeakcontainmentpressurevaluefora102percentpowerwithafailureofacontainmentspraypumpanda60secondMFIVclosuretimeresultsinamaximumpeakcontainmentpressureof55.946psig.Thedesignpressureforcontainmentis44psig.Thedifferencesintheresultsarebasedonnon-conservativeassumptionsintheoriginalanalysis.Theparametersthatmostsignificantlyaffectedtheoutcomewerefeedwaterflowrateandinitialcontainmentpressureandhumidity.Intheoriginalanalysis,thefeedwaterflowratetothefaultedsteamgeneratorwasassumedtoramplinearlyfor60secondMFIVclosure.TheMFIVsaregatevalves;therefore,thisassumptionwouldbenon-conservative.Aconservativeapproachwouldconsiderthisassumptionasastepchangeintheflowrateat60seconds.Theinitialcontainmentpressurewasassumedtobe14.7psia.TechnicalSpecification3.6.1.4allowsforaninternalrangeofpressuresandpermitsacontainmentpressureofhigherthan14.7psia.ThehighervalueisassumedfortherevisedMSLBaccidentanalysis.Containmentinitialhumidity,althoughnotaTechnicalSpecification,cannon-conservativelyimpactpeakcontainmentpressureifnotaccountedfor.Theoriginalassumptions,therefore,weredeterminedtocontainsomenon-conservatismsthatresultedinhigherthanexpectedpeakcontainmentpressurewhenre-analyzed.NRCFORM3BBAIB.1888)
U.S.NUCLEARREGULATORY COMMISSION APPROVEDBYOMBNO.3150-0104 EXPIRES0613012001 FACILITYNAME(1)St.LucieUnit1DOCKETNUMBER{2)05000335PAGE(3)Page1of8TITLE(4)Non-Conservative MSLBAnalysisInputsResultinOperation ofFacilityOutsideDesignBasesMONTHDAYEVENTDATE(5LERNUMBER6)SEQUENTIAL REVISIONNUMBERNUMBERMONTHDAYREPORTDATE7IFACIUTYNAMEOTHERFACILITIES INVOLVED6OOCKETNUMBER1'219981998-009-00011999FACIUTTNAMEOOCKETNUMBOlOPERATING MODE(9)20.2201(b) 20.2203(a)
NRCFOAM366A(6.'I998)4lLlCENSEEEVENTREPORT(LER)TEXTCONTINUATIONU.S.NUCLEARREGULATORYCOMMISSION~FACILITYNAME(1)St.Lucie'nit1DOCKETNUMBER205000335LERNUMBER(6)SEQUENTIALREVISIONNUMBERNUMBER1998-009.-00PAGE(3)Page7of8TEXTllfmorespeceisrequired,useedditionelcopiesofNRCForm366AI(17)AnalysisofSafetySignificance(cont'd)Theresultofthisre-analysisdemonstratesapotentialneedforareductioninfeedwatermassadditiontocontainmentforUnit1.Manyengineeringsolutionscanbeconsidered,includingmodificationoftheMFIVclosuretimes.Afasterresponseinclosuretime,suchasintheUnit2design,clearlybenefitsinincreasedmargintothedesignlimitof44psig.Abestestimate102%powercasewithsafeguardsavailableisprovidedintheABB-CEcalculation.Case2oftheMSLBcontainmentresponsecreditsnormaloperationofthemainfeedwaterregulatingvalvesandutilizesrealisticinputdata.Theresultsofthiscasedemonstrateapeakcontainmentpressureof43.339psig.Thisvalueisbelowthecontainmentdesignvalueof44psig.Althoughthiscaseisnotaboundingcaseforanalysisconsideration,itdemonstratesthatpressuresremainbelowdesignforaMSLBmassandenergyreleaseinsidecontainmentwithrealisticinputassumptions.ThisevaluatedcaseprovidespartofthebasesforoperabilityofUnit1containment.TheMSLBanalysisispostulatedtoreachapeaktemperatureofapproximately375Fat42.2seconds.Ztwasidentifiedthat11ofthe37in-containmentEQDocPacsenvelopthe375Fpostulatedpeaktemperature.Section4.3ofEQDocPac2998-A-451-1000(page1000-4-5)hasadiscussionofthermal.lagfortheUnit2insidecontainmentMSLB,andconcludesthattheactualtemperatureexperiencedbycomponentsareboundedbythecontainmentLOCAtemperatureprofiles.TheseUnit2resultsareapplicablefortheUnit1in-containmentEQDocPacsthatarenotenvelopedbythe375Ftemperaturepeak.Figures4-5and4-6oftheDocPacshowatypicalinstrumentcableandRosemounttransmitterandthetemperaturelagfor.045inchesbelowthesurfaceofthecable(typicalthicknessofacablejacket)andthesurfacetemperatureofthetransmitterwhenexposedtoatypicalMSLBprofile.TheseitemsconservativelyrepresentalloftheEQequipmentthatwouldbeexposedtoanin-containmentMSLB.FromtheplotofthesurfacetemperatureofthecableinFigure4-6oftheDocPac,thepeaktemperatureisapproximately385Fat45secondsenvelopingthepostulatedpeakforUnit1.Theplotsofthetransmittersurfacetemperatureandat.045belowthesurfaceofthecable(atthecableinsulation),showsthatthetemperatureofthetransmitterreachesapproximately245Fandtheinsulationofthecablejustbarelyexceeds260F.SincebothofthesetemperaturesarebelowtheUnit1LOCAtemperatureof270F,thequalificationoftheEQequipmentwillnotbeadverselyaffectedandwouldremainoperable.ThedoseconsequencesforaMSLBinsidecontainmentareboundedbytheMSLBoutsidecontainmentandtheLOCAevent.TechnicalSpecificationoperabilityisbasedontheLOCA,nottheMSLBevent.Furthermore,significantmarginexistsabovetheNRCFORM388AI8.1998)  
{2){v)50.73(a)(2)(i)50.73{a){2)(viii)
THISREPORTISSUBMITTED PURSUANTTOTHEREQUIREMENTS OF10CFREt(Checkonoormore){11)POWERLEVEL(10)10020.2203(0)(1) 20.2203(a)(2)
(i)20.2203(a)(2)
(ii)20.2203(a)(2)(iii) 20.2203(a)(2)(iv) 20.2203(a)(3)
(i)20,2203(o)(3)
(ii)20.2203(a)(4)50.36{c){1)50.36(c)(2)
X50.73{a)(2){ii) 50.73(a)(2)(iii)50.73(a)(2)(iv) 50.73(a)(2)
{v)50.73(a)(2)(vii)50.73(aw2)(x) 73.71OTHERSpecifyinAbstractbeloworInNRCForm36SAHAMELICENSEECONTACTFORTHISLERl12)TELEPHONE NUMBERSnorudeAresCode)KennethWFrehafer, Licensing Engineer(561)467-7748COMPLETEONELINEFOREACHCOMPONENT FAILUREDESCRIBED INTHISREPORT13CAUSESYSTEMCOMPONENT MANUFACTURER REPORTABLE TOEPIXCAUSESYSTEMCOMPONENT MANUFACTURER REPORTABLE TOEPIXBNHN/AN/ANOSUPPLEMENTAL REPORTEXPECTED(14)YES{IfYes,completeEXPECTEDSUBMISSION DATE).XNOEXPECTEDSUBMISSION DATE{15)MONTHDAYABSTRACT/Limitto1400spaces,i.o.,opproximately 15single-spaced typewritten linesi(16)OnDecember23,1998,St.Lucieengineering personnel determined thatthedraftresultsofaUnit1mainsteamlinebreakcontainment re-analysis indicateanunexpected higherpeakcontainment pressureof55.946psig.TheUnit1containment designpressureis44psig.Thedifference inthere-analysis valueandtheoriginalcontainment peakpressurevalue"isattributed tosomenon-conservative assumptions intheoriginalanalysis.
Themostsignificant assumptions werefeedwater flow,feedwater isolation, andinitialcontainment pressure.
Thenon-conservatism identified isintheinputdataoriginally usedtoperformtheanalysis.
St.Luciedetermined thatcontainment remainsoperablewithanoperability assessment performed pursuanttoGenericLetter91-18.Longtermcorrective actionsincludereviewofsafetyrelatedcomponent differences betweenUnits1and2,re-baseliningthelowtemperature overpressureanalysis, andeitherperformmodifications or.changethelicensing anddesignbasisoftheMSLBpeakcontainment pressureanalysis.
NRCFOAM306IS.1999)
NRCFORM366A(6-1888)LICENSEEEVENTREPORT(LER)TEXTCONTINUATION U.S.NUCLEARREGULATORY COMMISSION
,FACILITY NAME(1)St.LucieUnit1OOCKETNUMBER(2)05000335LERNUMBER(6)SEQUENTIAL REVISIONNUMBERNUMBER1998-009-00PAGE(3)Page2of8TEXTllfmorespeceisrequired, useedditionelcopiesofNRCForm366AJ(17)Description ofEventOnDecember23,1998,St.LucieUnit1wasinMode1at100percentreactorpower.Afterreviewing adraftUnit1MainSteamLineBreak{MSLB),Containment re-analysis, St.LucieEngineering concluded thatthedraftanalysisresultsindicated anunexpected higherpeakcontainment pressureof55.946psig.TheUnit1containment designpressureis44psig.Thedraftcalculation, CENP007-ST98-C-012, "St.LucieUnit1Containment MSLBMassandEnergyandPressure/Temperature ResponseAnalysis,"
wasperformed byABBandwastransmitted byABB-CEletterST-98-763 forFPLtoreviewandcomment.Thedifference inthere-analysis valueandtheoriginalcontainment peakpressurevalueisattributed tosomenon-conservative assumptions intheoriginalanalysis.
Themostsignificant assumptions werefeedwater flow,feedwater isolation, andinitialcontainment pressure.
Thenon-conservatism identified isintheinputdataoriginally usedtoperformtheanalysis.
Thiscondition wasreportedtotheNRCviatheemergency notification system(ENS)asanon-emergency reportpursuantto10CFR50.72(b)(1)(ii)onDecember23,1998.Engineering performed anoperability assessment inaccordance.
withGenericLetter91-18anddetermined thatcontainment remainsoperable.
Longtermcorrective actionsarebeingformulated toeitherimplement changestorestoretheMSLBcontainment analysisresultsorchangetheMSLBcontainment analysislicensing basis.CauseofEventThecauseforthehigherpeakpressureinthere-analyzed MSLBeventisthatnon-conservative assumptions wereusedintheoriginalanalysisofrecord.TheoriginalMSLBanalysisofrecordwasdeveloped jointlybetweenCombustion Engineering (massenergyinput)andEBASCO(containment performance)
.Thisanalysisconsidered aspectrumofbreaksizes,initialpowerlevels,andsinglefailures.
Themostsignificant non-conservative inputassumptions dealtwithfeedwater flow,feedwater isolation, andinitialcontainment pressure.
Thiscondition wasnotpreviously identified because,asdiscussed below,aformalre-analysis oftheMSLB'containment responsewasneverperformed.
Subsequent sensitivity studiesagainsttheoriginalMSLBcontainment responseanalysisofrecordwereperformed duringtheSt.LucieUnit1stretchpoweranalyses.
Additionally, themorerecentSteamGenerator Replacement project(SGRp)didnotincludeare-baselineoftheoriginalMSLBcontainment responseanalysisofrecord.Replacement steamgenerators (RSGs)wereinstalled duringtheFall1997Unit1refueling outage.TheSGRPdidnotincludeare-baseline oftheaffectedUFSARaccidentanalyses.
Theimpactstoexistinganalyses, including MSLB,wereevaluated pursuantto10CFR50.59.Theevaluations addressed potential impactsofcriticalparameter changesontheanalysesofrecord.Inallcases,theRSGimpactsoncriticalparameters wereevaluated asbeingboundedbytheanalysisofrecord,butdidnotidentifythelatentnon-conservatisms intheoriginalMSLBinsidecontainment analysis.BecausetheRSGs'hanges represented competing effectsontheMSLBanalysis, acalculation wasperformed byFramatone Technologies Inc.(FTI)toquantifythenetNRCFORM388A(8.1888)  
,1 NRCFORM366A(6-1998)LICENSEEEVENTREPORT(LER)TEXTCONTINUATION U.S.NUCLEARREGULATORY COMMISSION
.FACILITY NAMEI1)St.LucieUnit1DOCKETNUMBER2)05000335LERNUMBERIS)SEQUENTIAl REVISIONNUMBERNUMBER1998-009-00PAGEI3)Page3of8TEXT/Ifmorespaceisrequired, useadditional copiesofNRCFarm3MA/I17)CauseofEvent(cont'd)impactontheanalysisofrecord.Themost,significant compensating effectwasfromanintegralsteamlinefloworifice.Theorificewasdesignedtoreducetheeffective breaksize.Thisorificewasmorethansufficient tooffsettheotherSGRPchanges(i.e.,higheroperating pressure/temperature) thatadversely impacttheMSLBanalysis).
Therefore, theoriginalMSLBanalysisremainedboundingfortheRSGs.Engineering conducted self-assessment reviewsofmotoroperatedvalves(MOVs)inpreparation foranNRCauditoftheGL89-10PrograminOctober1997.DuringreviewoftheMFIVsconcernswereidentified withrespect,to feedwaterassumptions usedintheoriginalMSLBanalysis.
Specifically, thefeedwaterflowisolation wasassumedasa60-second linearramp.Actualvalvecharacteristics fortheMPIVsweremoreconsistent withastepchangeinflowat60seconds.Additionally, theanalysisdidnotappeartoconsiderblowdownofwaterremaining inthefeedwaterpipingafterMFIVactuation.
Also,theoriginalassumptions fortheflowsplitbetweenthefaultedandunfaulted generator wereindetermanent andpotentially non-conservative.
Theeffectoftheseassumptions couldmeanthattheactualflowishigherthanthatassumedintheanalysis.
BecausetheMSLBanalysisofrecordhadbeenaugmented bythePTIcalculations performed fortheSGRP,theseeffectsneededtobeevaluated inadditiontotheRSGeffects.TheSGRPwasrequested toperformadditional sensitivities toensurethattheimpactofthenewlydiscovered feedwaterassumption concernsremainedboundedbytheoriginalMSLBanalysis.
Are-analysis oftheFTIcalculation wasperformed, anditwasconcluded thatsufficient marginfromthesteamlineorificesremainedtoaccommodate thenewfeedwaterflowassumptions.
Basedonthisevaluation, allevaluated effectsremainedboundedbytheoriginalMSLBanalysisofrecord,andnooperability ordesignconcernsexisted.Althoughnotrequired, adecisionwasmadeatthistimetore-baseline theMSLBanalysistofacilitate futureoperability andmodification evaluations.
Thenewanalysiswascompetitively bidandacontractawardedtoABB-CE.Itwasrecognized thatinputstotheanalysiswouldneedtoberefinedandsuppliedbyFPLinorderforthereanalysis toremainboundedbytheoriginalUPSARanalysis.
Specifically, thefeedwaterflowwouldneedtobemodeledtoevaluatetheactualfeedwaterflowsexpectedandremovethesimplifying assumptions.
FPLandABB-CEhavebeenworkingcloselytorefinetheinputs.However,duringtheprojectseveraladditional non-conservative assumptions intheoriginalanalysiswereidentified whichcouldnotbejustified forthereanalysis.
Themostsignificant oftheseare:(1)initialcontainment pressurewasassumedas0psiginsteadof2.4psigasallowedbytechnical specifications; and(2)actualflowtothefaultedsteamgenerator couldbehigherthanthetwicenormalfeedwaterflowassumedintheoriginalanalysisduetothepumpsbeingfurtheroutonthepumpcurve.Thesenon-conservative inputsresultedinthehigherpeakpressures reportedbythisLER.NRCFORM3BBAIB.1888)
NRCFOAM366A(6.1998)~FACILITYNAME(1)St.LucieUnit1LICENSEEEVENTREPORT(LER)TEXTCONTINUATION DOCKETNUMBER(2)05000335U.S.NUCLEARREGULATORY COMMISSION LERNUMBER(6)PAGE(3)SEQUENTIAL REVISIONNUMBERNUMBERPage4of8TEXT(Ifmorospaceisrequired, useadditional copiesofNRCForm366Ai(17)1998-009-00CauseofEvent(cont'd)AnalysesRe-BaseLiningTheimpactofthelatentnon-conservatisms intheoriginalMSLBinsidecontainment analysiswasnotrealizeduntilacompletere-analysis wasperformed.
Onepotential genericimplication wouldbeforanyotheranalysesthathavenotbeenre-baselined,butratherevaluated onanindividual changebasis.St.Luciereviewedapplicable analyseswiththefollowing results.Thefuelanalysesarere-analyzed foreachfuelcycle.TheLOCAcontainment analysiswasre-analyzed in1993.OnlytheLowTemperature Overpressure(LTOp)analysiswasidentified asnothavingbeenre-runsinceoriginallicense.TheLTOPanalysisiscurrently beingre-baselined.Therefore, allexistinganalysesofrecordhaveeitherbeenorarebeingbase-lined.
Theuseofnon-conservative inputsduringthedevelopment ofanynewfutureanalysesisprecluded byexistingengineering procedures.
Procedural requirements ensurethatinputstransmitted toA/Eareindependently verifiedpriortousebytheA/E.ThedesignoftheUnit1andUnit2mainfeedwater isolation valves(MFIVs)aresignificantly different.
TheclosuretimesforUnit2areapproximately onetenththatforUnit1.However,thecontainment designandotherparameters significant totheMSLBeventareessentially identical.
Basedonthisobservation, anothergenericcorrective actionwillbetoidentifyanysimilarsignificant differences insafetyrelatedsystemsandcomponents betweenthetwounitsanddetermine iftheyhavebeenadequate'ly reflected intheanalyses.
TheSt.LucieUnit2MSLBcontainment analysisdoesnotcontainthesesamenon-conservative inputdataassumptions initsanalysis.
Therefore, thiscondition isnotapplicable t'oUnit2.AnalysisofEventThedraftresultsoftheUnit1containment MSLBmassandenergyandpressureandtemperature responseanalysisdonotmeetthemaximumcontainment pressuredesigncriteriaof44psig.Basedonthedraftdocument, acondition wasdiscovered duringplantoperation thatresultsinthenuclearpowerplant,St.LucieUnit1,beinginacondition thatisoutsidethedesignbasisoftheplant.Asaresult,thiscondition wasreportedasanon-emergency reportunder10CFR50.72(b)(1)(ii)(B),"Anyeventorcondition duringoperation thatresultsinthenuclearpowerplantbeing:'Znacondition thatisoutsidethedesignbasisoftheplant.'"Basedonthistypeofreport,theLicenseeisrequiredtosubmitanLERwithin30days.TheLERcomplieswith10CFR50.73(a)(2)(ii)(B)forreporting acondition thatisoutsidethedesignbasisoftheplant.AnalysisofSafetySignificance IThedraftMSLBcontainment analysiswassubsequently finalized andissuedtoSt.Lucie.Allconclusions inthissectionarebasedonthefinalanalysisresults.TheresultsoftheMSLBcontainment analysisdonotaffecttheTechnical Specification NRCFORM388A(8.1998)
NRCFORM366A(6-1998)LICENSEEEVENTREPORT(LER)TEXTCONTINUATION U.S.NUCLEARREGULATORY COMMISSION
~FACILITYNAME(1)St.LucieUnit1OOCKETNUMBER2)05000335LERNUMBER(6)SEQUENTIAL REVISIONNUMBERNUMBER1998-009-00PAGE(3)Page5of8TEXT(Ifmorespaceisrequired, useadditional copiesoffVRCForm3MA)(17)AnalysisofSafetySignificance (cont'd)operability ofthecontainment orrelatedsystems.Specifically, Technical Specification operability forTS3/4.6.1.2, CONTAINMENT LEAKAGE,andTS3/4.6.1.6, CONTAINMENT VESSELSTRUCTURAL INTEGRITY, arebasedonapeakcontainment pressureof39.6psigforthelimitingdesignbasisLOCA,nottheMSLB.DuringaMSLBeventthereisarelatively minorreleaseofradioactivity intothecontainment.
Also-notethatinthemorelimitingcaseforoff-sitedose,theMSLBisassumedtooccuroutsidethecontainment wherethereisadirectpathtotheenvironment.
Therefore, thelicensing basisforthecontainment operability istheLOCA,nottheMSLB.Asstatedinthepreviousparagraph, thedefinition ofcontainment operability isnotbasedontheMSLBanalysis.
However,thefunctionofthissafetyrelatedstructure canstillbeshownnottobecompromised forthere-analyzed MSLBevent.Althoughthecalculated higherevaluated peakpressureisclosertotheultimatefailureofthecontainment, significant marginabove56psigremains.TheSt.LucieIndividual PlantExamination (IPE)submittal estimates acontainment failurepressureof95pslg.Abestestimatecasewasalsoperformed byABB-CE.Thisbestestimatecaseconsidered morerealistic plantassumptions inlieuofthemoreconservative designbasisassumptions.
Specifically, themainfeedregulating valves(MFRVs)areassumedtoremainintheirpre-accident positionandbothtrainsofemergency corecoolingsystems(ECCS)areassumedtobeoperable.
Thedesignbasiscaseconservatively andnon-mechanistically assumesthatbothMFRVsgofullyopenatthebeginning oftheaccident.
Thisresultsinamuchlargerinflowoffeedwatertothefaultedgenerator thanwouldactuallyoccur.Thebestestimateassumption oftheMFRVsremaining intheirpre-accident condition isstillconservative inthatthemostlikelyresponsetothebreakwouldbefortheMFRVstoclosedowninresponsetogenerator swell.Thebestestimateassumption thatbothtrainsofECCSwouldbeavailable doesnotmeetdesignbasisrequirements forsinglefailure,butisreasonable fortheevaluated scenario.
ThemostprobablemeansofacompletelossofoneECCStrain(containment sprayandcoolers)wouldrequireaLOOPandsubsequent emergency dieselgenerator failure.BecauseaLOOPwouldgreatlyreducethepeakpressureasaresultofthereactorcoolantpumps(RCPs)andmainfeedwaterpumpstripping, aLOOPscenarioisnotlimitingforthisaccident.
Therefore, theonlyapplicable postulated failureofECCStrainswouldinvolveasingleECCScomponent.
Thesearesafetyrelatedcomponents ofhighreliability thatareextensively testedandmaintained.
Thebestestimatecaseresultsinapeakcontainment pressureof43.339psig,whichisbelowthecurrentUFSARdesignpressureof44psig.AlthoughthebestestimatecaseassumesnormalMFRVoperation andthatbothtrainsofECCSareavailable, operat'ing constraints associated withtheseparameters arenotimposedbytheassessment.
Technical Specification operability isbasedontheLOCAeventandnottheMSLBevent.Significant marginexistsbetweenthepeakcalculated MSLBpressureandanticipated failureofthecontainment.
Thebestestimatecasedemonstrates thatunderconditions thatwouldnormallybeexpected, thepeakpressurefromapostulated MSLBremainsbelowdesign.NRCFORM368AI9.1998)
NRCFORM366AIB-)998)LICENSEEEVENTREPORT(LER)TEXTCONTINUATION U.S.NUCLEARREGULATORY COMMISSION
'FACIUTYNAMEI1)St.LucieUnit1DocKETNUMBERI2)05000335LERNUMBERI6)SEQUENTIAL REVISIONNUMBERNUMBER1998-009-00PAGEI3)Page6of8TEXT/Ifmorespaceisrequired, useadditional copiesofNRCForm366AJI17)AnalysisofSafetySignificance (cont'd)St.LucieUnit1UFSARSection6.2.1.1de'scribes thedesignbasesforcontainment.
Thecontainment vesselisdesignedinaccordance withtheASMECodeSectionIII,ClassMC.Themaximuminternalpressure, asdefinedinArticleNE-3112ofthecode,is44psig.Thisvalueisdocumented inSection6.2.1.2oftheUnit1UFSAR.Thisvalueisalsodccumented intheUnit1Technical Specification designfeatures, section5.2.2.Duetothelargeinventory designsteamgenerators ofCEdesignedplants,theMSLBeventtypically producesthepeakcontainment pressureandtemperature.
However,UFSARSection6.2.1.1.b notesthattheequipment surfacetemperature islaggedandwillgenerally notexperience theelevatedtemperatures resulting fromapuresteamblowdownresponse(MSLB).Assuch,forthetemperature
: response, theLOCAeventisboundingandestablishes theenvironmental qualification criteriaandtemperature limitations, asdescribed below.TheMSLBcontainment re-analysispeakcontainment pressurevalueof55.946psigistheparameter evaluated inthisLER.Containment vesselfailureischaracterized intheSt.LucieUnits1and2IPEsubmittal datedDecember1993.Specifically, AppendixG,Containment FailurePressureCharacterization, providesanassessment ofcontainment performance basedonthemethodology ofNUREG/CR-2442.
Thisassessment estimates afailurepressureof95psigfortheSt.LucieUnit1and2containment vessels.Thus,aMSLBcontainment responseanalysispeakpressureof55.946psigisboundedbytheestimated failurepressureof95psig.ItisnotedthattheLOCAcontainment analysiswasupdatedfromtheoriginalcontainment analysisforbothSt.LucieUnits1and2in1993andisdocumented intherespective UFSARs.TheMSLBcontainment re-analysis peakcontainment pressurevaluefora102percentpowerwithafailureofacontainment spraypumpanda60secondMFIVclosuretimeresultsinamaximumpeakcontainment pressureof55.946psig.Thedesignpressureforcontainment is44psig.Thedifferences intheresultsarebasedonnon-conservative assumptions intheoriginalanalysis.
Theparameters thatmostsignificantly affectedtheoutcomewerefeedwater flowrateandinitialcontainment pressureandhumidity.
Intheoriginalanalysis, thefeedwater flowratetothefaultedsteamgenerator wasassumedtoramplinearlyfor60secondMFIVclosure.TheMFIVsaregatevalves;therefore, thisassumption wouldbenon-conservative.
Aconservative approachwouldconsiderthisassumption asastepchangeintheflowrateat60seconds.Theinitialcontainment pressurewasassumedtobe14.7psia.Technical Specification 3.6.1.4allowsforaninternalrangeofpressures andpermitsacontainment pressureofhigherthan14.7psia.ThehighervalueisassumedfortherevisedMSLBaccidentanalysis.
Containment initialhumidity, althoughnotaTechnical Specification, cannon-conservatively impactpeakcontainment pressureifnotaccounted for.Theoriginalassumptions, therefore, weredetermined tocontainsomenon-conservatisms thatresultedinhigherthanexpectedpeakcontainment pressurewhenre-analyzed.
NRCFORM3BBAIB.1888)
NRCFOAM366A(6.'I998)4lLlCENSEEEVENTREPORT(LER)TEXTCONTINUATION U.S.NUCLEARREGULATORY COMMISSION
~FACILITYNAME(1)St.Lucie'nit 1DOCKETNUMBER205000335LERNUMBER(6)SEQUENTIAL REVISIONNUMBERNUMBER1998-009.-00PAGE(3)Page7of8TEXTllfmorespeceisrequired, useedditionel copiesofNRCForm366AI(17)AnalysisofSafetySignificance (cont'd)Theresultofthisre-analysis demonstrates apotential needforareduction infeedwater massadditiontocontainment forUnit1.Manyengineering solutions canbeconsidered, including modification oftheMFIVclosuretimes.Afasterresponseinclosuretime,suchasintheUnit2design,clearlybenefitsinincreased margintothedesignlimitof44psig.Abestestimate102%powercasewithsafeguards available isprovidedintheABB-CEcalculation.
Case2oftheMSLBcontainment responsecreditsnormaloperation ofthemainfeedwater regulating valvesandutilizesrealistic inputdata.Theresultsofthiscasedemonstrate apeakcontainment pressureof43.339psig.Thisvalueisbelowthecontainment designvalueof44psig.Althoughthiscaseisnotaboundingcaseforanalysisconsideration, itdemonstrates thatpressures remainbelowdesignforaMSLBmassandenergyreleaseinsidecontainment withrealistic inputassumptions.
Thisevaluated caseprovidespartofthebasesforoperability ofUnit1containment.
TheMSLBanalysisispostulated toreachapeaktemperature ofapproximately 375Fat42.2seconds.Ztwasidentified that11ofthe37in-containment EQDocPacsenvelopthe375Fpostulated peaktemperature.
Section4.3ofEQDocPac2998-A-451-1000 (page1000-4-5) hasadiscussion ofthermal.lagfortheUnit2insidecontainment MSLB,andconcludes thattheactualtemperature experienced bycomponents areboundedbythecontainment LOCAtemperature profiles.
TheseUnit2resultsareapplicable fortheUnit1in-containment EQDocPacsthatarenotenveloped bythe375Ftemperature peak.Figures4-5and4-6oftheDocPacshowatypicalinstrument cableandRosemount transmitter andthetemperature lagfor.045inchesbelowthesurfaceofthecable(typicalthickness ofacablejacket)andthesurfacetemperature ofthetransmitter whenexposedtoatypicalMSLBprofile.Theseitemsconservatively represent alloftheEQequipment thatwouldbeexposedtoanin-containment MSLB.Fromtheplotofthesurfacetemperature ofthecableinFigure4-6oftheDocPac,thepeaktemperature isapproximately 385Fat45secondsenveloping thepostulated peakforUnit1.Theplotsofthetransmitter surfacetemperature andat.045belowthesurfaceofthecable(atthecableinsulation),
showsthatthetemperature ofthetransmitter reachesapproximately 245Fandtheinsulation ofthecablejustbarelyexceeds260F.Sincebothofthesetemperatures arebelowtheUnit1LOCAtemperature of270F,thequalification oftheEQequipment willnotbeadversely affectedandwouldremainoperable.
Thedoseconsequences foraMSLBinsidecontainment areboundedbytheMSLBoutsidecontainment andtheLOCAevent.Technical Specification operability isbasedontheLOCA,nottheMSLBevent.Furthermore, significant marginexistsabovetheNRCFORM388AI8.1998)  


NRCFORM366A(8.1998)LICENSEEEVENTREPORT(LER)TEXTCONTINUATIONU.S.NUCLEARREGULATORYCOMMISSION~FACILITYNAME(1)St.LucieUnit1DOCKETNUMBERI205000335LERNUMBER(6)SEQUENTIALREVISIONNUMBERNUMBER1998-009-00PAGE(3)Page8of8TEXT/ifmorespaceisrequired,useadditionalcopiesofNRCForm3MA)I17)AnalysisofSafetySignificance(cont'd)calculatedMSLBcontainmentanalysispeakpressuretoensurethatthecontainmentwouldnotfailasaresultofaMSLBinsidecontainment.Bestestimateanalysisdemonstratesthatundermoreprobableconditionsthecurrentdesignpressureof44psigwillnotbeexceeded.Basedontheseconsiderations,nooperabilityconcernexistsfortheconditionsstatedinthisLBR,andcontinuedplantoperationposesnoadverserisktothehealthandsafetyofthepublic.CorrectiveActions1.LongtermcorrectiveactionwillconsistofeithermodificationstoreducefeedwaterflowtothefaultedgeneratororachangetothelicensingbasisoftheMSLBpeakcontainmentpressuretoavalueofgreaterthan56psig.2.ThelowtemperatureoverpressureLTOPanalysiswasidentifiedasnothavingbeenre-runsinceoriginallicenseandiscurrentlybeingre-baselined.3.St.Luciewillreviewthegenericimplicationsofsimilarsignificantdifferences(similartothedifferenceinMFZVclosuretime)insafetyrelatedsystems/componentsbetweenthetwounits.OtherInformationNoneNoneNRCFORM388A(81998)}}
NRCFORM366A(8.1998)LICENSEEEVENTREPORT(LER)TEXTCONTINUATION U.S.NUCLEARREGULATORY COMMISSION
~FACILITYNAME(1)St.LucieUnit1DOCKETNUMBERI205000335LERNUMBER(6)SEQUENTIAL REVISIONNUMBERNUMBER1998-009-00PAGE(3)Page8of8TEXT/ifmorespaceisrequired, useadditional copiesofNRCForm3MA)I17)AnalysisofSafetySignificance (cont'd)calculated MSLBcontainment analysispeakpressuretoensurethatthecontainment wouldnotfailasaresultofaMSLBinsidecontainment.
Bestestimateanalysisdemonstrates thatundermoreprobableconditions thecurrentdesignpressureof44psigwillnotbeexceeded.
Basedontheseconsiderations, nooperability concernexistsfortheconditions statedinthisLBR,andcontinued plantoperation posesnoadverserisktothehealthandsafetyofthepublic.Corrective Actions1.Longtermcorrective actionwillconsistofeithermodifications toreducefeedwaterflowtothefaultedgenerator orachangetothelicensing basisoftheMSLBpeakcontainment pressuretoavalueofgreaterthan56psig.2.Thelowtemperature overpressureLTOPanalysiswasidentified asnothavingbeenre-runsinceoriginallicenseandiscurrently beingre-baselined.3.St.Luciewillreviewthegenericimplications ofsimilarsignificant differences (similartothedifference inMFZVclosuretime)insafetyrelatedsystems/components betweenthetwounits.OtherInformation NoneNoneNRCFORM388A(81998)}}

Revision as of 15:33, 29 June 2018

LER 98-009-00:on 981223,noted That Facility Operated Outside of Design Basis.Caused by non-conservative MSLB Analysis Inputs.Will Review SR Component Differences Between Units & Will re-baseline Ltop Analysis.With 990120 Ltr
ML17229A990
Person / Time
Site: Saint Lucie NextEra Energy icon.png
Issue date: 01/20/1999
From: FREHAFER K W, STALL J A
FLORIDA POWER & LIGHT CO.
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
GL-91-18, L-99-012, L-99-12, LER-98-009, LER-98-9, NUDOCS 9901270103
Download: ML17229A990 (13)
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Text

CATEGORYleREGULATORY INFORMATION DISTRIBUTION SYSTEM(RIDS)ACCESSION NBR:9901270103 DOC.DATE:

99/01/20NOTARIZED:

NOFACIL:50-335 St.LuciePlant,Unit1,FloridaPower&LightCo.AUTH.NAMEAUTHORAFFILIATION FREHAFER,K.W.

FloridaPower&LightCo.STALL,J.A.

FloridaPower&.LightCo.RECIP.NAME RECIPIENT AFFILIATION DOCKET¹05000335

SUBJECT:

LER98-009-00:op 981223,noted thatfacilityoperatedoutsideofdesignbasis.Causedbynon-conservative MSLBanalysisinputs.WillreviewSRcomponent differences betweenunits&willre-baseline LTOPanalysis.

With990120ltr.DISTRIBUTION CODE:IE22TCOPIESRECEIVED:

LTRIENCLiSIZE:TITLE:50.73/50.9 LicenseeEventReport(LER),IncidentRpt,etc.NOTES:RECIPIENT IDCODE/NAME PD2-3PD'NTERNAL:

ACRSAEOD/SPD/RRAB NRR/DE/ECGB NRR/DE/EMEB NRR/DRCH/HOHB NRR/DRPM/PECB RES/DET/EIB EXTERNAL:

LSTLOBBYWARDNOACPOORE,W.NRCPDRCOPIESLTTRENCL111111111111111111111,1RECIPIENT IDCODE/NAME GLEAVES,W AEODCENTRDEBNRR/DRCH/HICB NRR/DRCH/HQMB NRR/DSSA/SPLB RGN2FILE01LITCOBRYCE,JHNOACQUEENER,DS NUDOCSFULLTXTCOPIESLTTRENCL11221111111'1111111111CNOTETOALL"RIDS"RECIPIENTS:

PLEASEHELPUSTOREDUCEWASTE.TOHAVEYOURNAMEORORGANIZATION REMOVEDFROMDISTRIBUTION LISTSOP.REDUC-THENUMBER.OF COPIESRECEIVEDBY-OUORYOURORGANZATION,CONTACTTHEDOCUMENTCONTRO'ESK (DCD)ONEXTENSION 415-2083FULLTEXTCONVERSION REQUIREDTOTALNUMBEROFCOPIESREQUIRED:

LTTR23ENCL23

FloridaPower5LightCompany.6351S.OceanDrive,JensenBeach,FL34957January20,1999L-99-01210CFR550.73U.S.NuclearRegulatory Commission Attn:DocumentControlDeskWashington, D.C.20555Re:St.LucieUnit1DocketNo.50-335Reportable Event:1998-009-00 DateofEvent:December23,1998Non-Conservative MSLBAnalysisInputsResultin0erationofFacilit OutsideDesinBasesTheattachedLicenseeEventReport1998-009isbeingsubmitted pursuanttotherequirements of10CFRg50.73toprovidenotification ofthesubjectevent.Verytrulyyours,J.A.StallVicePresident St.LucieNuclearPlantJAS/EJW/KWF Attachment cc:RegionalAdministrator, USNRCRegionIISeniorResidentInspector, USNRC,St.LucieNuclearPlant'ir'ir0i270i03

'rr'ir0i20 PDRADQCK05000335SPDRanFPLGroupcompany NRCFORM366{6-1996)LtCENSEEEVENTREPORT(LER)(Seereverseforrequirednumberofdigits/characters foreachblock)Eslimated burdenperresponsetocomplywiththismandatory Inforrnagon co!lection roquest:50hrs.Roportodlossonslearnedaroincorporated intotholicensing processandfodbacktoindustry.

Forwardcommentsregarding burdenestimatetotheRecordsManagement Branch{TAF33)U.S.Roc)earRegulatory Commission, Washington, DC2t$5$4001,andlothePaperwrxk Reduction Proioct(31500104),

OfficeofManagement andBudgol,Washington.

Dc20503.Ifaninformation collection doesnotdisplayacurrently validOMBcontrolnumber,theNRCmaynotconductorsponsor,andapersonhrnolrequiredlorespondto,thoInformation coltecgon.

U.S.NUCLEARREGULATORY COMMISSION APPROVEDBYOMBNO.3150-0104 EXPIRES0613012001 FACILITYNAME(1)St.LucieUnit1DOCKETNUMBER{2)05000335PAGE(3)Page1of8TITLE(4)Non-Conservative MSLBAnalysisInputsResultinOperation ofFacilityOutsideDesignBasesMONTHDAYEVENTDATE(5LERNUMBER6)SEQUENTIAL REVISIONNUMBERNUMBERMONTHDAYREPORTDATE7IFACIUTYNAMEOTHERFACILITIES INVOLVED6OOCKETNUMBER1'219981998-009-00011999FACIUTTNAMEOOCKETNUMBOlOPERATING MODE(9)20.2201(b) 20.2203(a)

{2){v)50.73(a)(2)(i)50.73{a){2)(viii)

THISREPORTISSUBMITTED PURSUANTTOTHEREQUIREMENTS OF10CFREt(Checkonoormore){11)POWERLEVEL(10)10020.2203(0)(1) 20.2203(a)(2)

(i)20.2203(a)(2)

(ii)20.2203(a)(2)(iii) 20.2203(a)(2)(iv) 20.2203(a)(3)

(i)20,2203(o)(3)

(ii)20.2203(a)(4)50.36{c){1)50.36(c)(2)

X50.73{a)(2){ii) 50.73(a)(2)(iii)50.73(a)(2)(iv) 50.73(a)(2)

{v)50.73(a)(2)(vii)50.73(aw2)(x) 73.71OTHERSpecifyinAbstractbeloworInNRCForm36SAHAMELICENSEECONTACTFORTHISLERl12)TELEPHONE NUMBERSnorudeAresCode)KennethWFrehafer, Licensing Engineer(561)467-7748COMPLETEONELINEFOREACHCOMPONENT FAILUREDESCRIBED INTHISREPORT13CAUSESYSTEMCOMPONENT MANUFACTURER REPORTABLE TOEPIXCAUSESYSTEMCOMPONENT MANUFACTURER REPORTABLE TOEPIXBNHN/AN/ANOSUPPLEMENTAL REPORTEXPECTED(14)YES{IfYes,completeEXPECTEDSUBMISSION DATE).XNOEXPECTEDSUBMISSION DATE{15)MONTHDAYABSTRACT/Limitto1400spaces,i.o.,opproximately 15single-spaced typewritten linesi(16)OnDecember23,1998,St.Lucieengineering personnel determined thatthedraftresultsofaUnit1mainsteamlinebreakcontainment re-analysis indicateanunexpected higherpeakcontainment pressureof55.946psig.TheUnit1containment designpressureis44psig.Thedifference inthere-analysis valueandtheoriginalcontainment peakpressurevalue"isattributed tosomenon-conservative assumptions intheoriginalanalysis.

Themostsignificant assumptions werefeedwater flow,feedwater isolation, andinitialcontainment pressure.

Thenon-conservatism identified isintheinputdataoriginally usedtoperformtheanalysis.

St.Luciedetermined thatcontainment remainsoperablewithanoperability assessment performed pursuanttoGenericLetter91-18.Longtermcorrective actionsincludereviewofsafetyrelatedcomponent differences betweenUnits1and2,re-baseliningthelowtemperature overpressureanalysis, andeitherperformmodifications or.changethelicensing anddesignbasisoftheMSLBpeakcontainment pressureanalysis.

NRCFOAM306IS.1999)

NRCFORM366A(6-1888)LICENSEEEVENTREPORT(LER)TEXTCONTINUATION U.S.NUCLEARREGULATORY COMMISSION

,FACILITY NAME(1)St.LucieUnit1OOCKETNUMBER(2)05000335LERNUMBER(6)SEQUENTIAL REVISIONNUMBERNUMBER1998-009-00PAGE(3)Page2of8TEXTllfmorespeceisrequired, useedditionelcopiesofNRCForm366AJ(17)Description ofEventOnDecember23,1998,St.LucieUnit1wasinMode1at100percentreactorpower.Afterreviewing adraftUnit1MainSteamLineBreak{MSLB),Containment re-analysis, St.LucieEngineering concluded thatthedraftanalysisresultsindicated anunexpected higherpeakcontainment pressureof55.946psig.TheUnit1containment designpressureis44psig.Thedraftcalculation, CENP007-ST98-C-012, "St.LucieUnit1Containment MSLBMassandEnergyandPressure/Temperature ResponseAnalysis,"

wasperformed byABBandwastransmitted byABB-CEletterST-98-763 forFPLtoreviewandcomment.Thedifference inthere-analysis valueandtheoriginalcontainment peakpressurevalueisattributed tosomenon-conservative assumptions intheoriginalanalysis.

Themostsignificant assumptions werefeedwater flow,feedwater isolation, andinitialcontainment pressure.

Thenon-conservatism identified isintheinputdataoriginally usedtoperformtheanalysis.

Thiscondition wasreportedtotheNRCviatheemergency notification system(ENS)asanon-emergency reportpursuantto10CFR50.72(b)(1)(ii)onDecember23,1998.Engineering performed anoperability assessment inaccordance.

withGenericLetter91-18anddetermined thatcontainment remainsoperable.

Longtermcorrective actionsarebeingformulated toeitherimplement changestorestoretheMSLBcontainment analysisresultsorchangetheMSLBcontainment analysislicensing basis.CauseofEventThecauseforthehigherpeakpressureinthere-analyzed MSLBeventisthatnon-conservative assumptions wereusedintheoriginalanalysisofrecord.TheoriginalMSLBanalysisofrecordwasdeveloped jointlybetweenCombustion Engineering (massenergyinput)andEBASCO(containment performance)

.Thisanalysisconsidered aspectrumofbreaksizes,initialpowerlevels,andsinglefailures.

Themostsignificant non-conservative inputassumptions dealtwithfeedwater flow,feedwater isolation, andinitialcontainment pressure.

Thiscondition wasnotpreviously identified because,asdiscussed below,aformalre-analysis oftheMSLB'containment responsewasneverperformed.

Subsequent sensitivity studiesagainsttheoriginalMSLBcontainment responseanalysisofrecordwereperformed duringtheSt.LucieUnit1stretchpoweranalyses.

Additionally, themorerecentSteamGenerator Replacement project(SGRp)didnotincludeare-baselineoftheoriginalMSLBcontainment responseanalysisofrecord.Replacement steamgenerators (RSGs)wereinstalled duringtheFall1997Unit1refueling outage.TheSGRPdidnotincludeare-baseline oftheaffectedUFSARaccidentanalyses.

Theimpactstoexistinganalyses, including MSLB,wereevaluated pursuantto10CFR50.59.Theevaluations addressed potential impactsofcriticalparameter changesontheanalysesofrecord.Inallcases,theRSGimpactsoncriticalparameters wereevaluated asbeingboundedbytheanalysisofrecord,butdidnotidentifythelatentnon-conservatisms intheoriginalMSLBinsidecontainment analysis.BecausetheRSGs'hanges represented competing effectsontheMSLBanalysis, acalculation wasperformed byFramatone Technologies Inc.(FTI)toquantifythenetNRCFORM388A(8.1888)

,1 NRCFORM366A(6-1998)LICENSEEEVENTREPORT(LER)TEXTCONTINUATION U.S.NUCLEARREGULATORY COMMISSION

.FACILITY NAMEI1)St.LucieUnit1DOCKETNUMBER2)05000335LERNUMBERIS)SEQUENTIAl REVISIONNUMBERNUMBER1998-009-00PAGEI3)Page3of8TEXT/Ifmorespaceisrequired, useadditional copiesofNRCFarm3MA/I17)CauseofEvent(cont'd)impactontheanalysisofrecord.Themost,significant compensating effectwasfromanintegralsteamlinefloworifice.Theorificewasdesignedtoreducetheeffective breaksize.Thisorificewasmorethansufficient tooffsettheotherSGRPchanges(i.e.,higheroperating pressure/temperature) thatadversely impacttheMSLBanalysis).

Therefore, theoriginalMSLBanalysisremainedboundingfortheRSGs.Engineering conducted self-assessment reviewsofmotoroperatedvalves(MOVs)inpreparation foranNRCauditoftheGL89-10PrograminOctober1997.DuringreviewoftheMFIVsconcernswereidentified withrespect,to feedwaterassumptions usedintheoriginalMSLBanalysis.

Specifically, thefeedwaterflowisolation wasassumedasa60-second linearramp.Actualvalvecharacteristics fortheMPIVsweremoreconsistent withastepchangeinflowat60seconds.Additionally, theanalysisdidnotappeartoconsiderblowdownofwaterremaining inthefeedwaterpipingafterMFIVactuation.

Also,theoriginalassumptions fortheflowsplitbetweenthefaultedandunfaulted generator wereindetermanent andpotentially non-conservative.

Theeffectoftheseassumptions couldmeanthattheactualflowishigherthanthatassumedintheanalysis.

BecausetheMSLBanalysisofrecordhadbeenaugmented bythePTIcalculations performed fortheSGRP,theseeffectsneededtobeevaluated inadditiontotheRSGeffects.TheSGRPwasrequested toperformadditional sensitivities toensurethattheimpactofthenewlydiscovered feedwaterassumption concernsremainedboundedbytheoriginalMSLBanalysis.

Are-analysis oftheFTIcalculation wasperformed, anditwasconcluded thatsufficient marginfromthesteamlineorificesremainedtoaccommodate thenewfeedwaterflowassumptions.

Basedonthisevaluation, allevaluated effectsremainedboundedbytheoriginalMSLBanalysisofrecord,andnooperability ordesignconcernsexisted.Althoughnotrequired, adecisionwasmadeatthistimetore-baseline theMSLBanalysistofacilitate futureoperability andmodification evaluations.

Thenewanalysiswascompetitively bidandacontractawardedtoABB-CE.Itwasrecognized thatinputstotheanalysiswouldneedtoberefinedandsuppliedbyFPLinorderforthereanalysis toremainboundedbytheoriginalUPSARanalysis.

Specifically, thefeedwaterflowwouldneedtobemodeledtoevaluatetheactualfeedwaterflowsexpectedandremovethesimplifying assumptions.

FPLandABB-CEhavebeenworkingcloselytorefinetheinputs.However,duringtheprojectseveraladditional non-conservative assumptions intheoriginalanalysiswereidentified whichcouldnotbejustified forthereanalysis.

Themostsignificant oftheseare:(1)initialcontainment pressurewasassumedas0psiginsteadof2.4psigasallowedbytechnical specifications; and(2)actualflowtothefaultedsteamgenerator couldbehigherthanthetwicenormalfeedwaterflowassumedintheoriginalanalysisduetothepumpsbeingfurtheroutonthepumpcurve.Thesenon-conservative inputsresultedinthehigherpeakpressures reportedbythisLER.NRCFORM3BBAIB.1888)

NRCFOAM366A(6.1998)~FACILITYNAME(1)St.LucieUnit1LICENSEEEVENTREPORT(LER)TEXTCONTINUATION DOCKETNUMBER(2)05000335U.S.NUCLEARREGULATORY COMMISSION LERNUMBER(6)PAGE(3)SEQUENTIAL REVISIONNUMBERNUMBERPage4of8TEXT(Ifmorospaceisrequired, useadditional copiesofNRCForm366Ai(17)1998-009-00CauseofEvent(cont'd)AnalysesRe-BaseLiningTheimpactofthelatentnon-conservatisms intheoriginalMSLBinsidecontainment analysiswasnotrealizeduntilacompletere-analysis wasperformed.

Onepotential genericimplication wouldbeforanyotheranalysesthathavenotbeenre-baselined,butratherevaluated onanindividual changebasis.St.Luciereviewedapplicable analyseswiththefollowing results.Thefuelanalysesarere-analyzed foreachfuelcycle.TheLOCAcontainment analysiswasre-analyzed in1993.OnlytheLowTemperature Overpressure(LTOp)analysiswasidentified asnothavingbeenre-runsinceoriginallicense.TheLTOPanalysisiscurrently beingre-baselined.Therefore, allexistinganalysesofrecordhaveeitherbeenorarebeingbase-lined.

Theuseofnon-conservative inputsduringthedevelopment ofanynewfutureanalysesisprecluded byexistingengineering procedures.

Procedural requirements ensurethatinputstransmitted toA/Eareindependently verifiedpriortousebytheA/E.ThedesignoftheUnit1andUnit2mainfeedwater isolation valves(MFIVs)aresignificantly different.

TheclosuretimesforUnit2areapproximately onetenththatforUnit1.However,thecontainment designandotherparameters significant totheMSLBeventareessentially identical.

Basedonthisobservation, anothergenericcorrective actionwillbetoidentifyanysimilarsignificant differences insafetyrelatedsystemsandcomponents betweenthetwounitsanddetermine iftheyhavebeenadequate'ly reflected intheanalyses.

TheSt.LucieUnit2MSLBcontainment analysisdoesnotcontainthesesamenon-conservative inputdataassumptions initsanalysis.

Therefore, thiscondition isnotapplicable t'oUnit2.AnalysisofEventThedraftresultsoftheUnit1containment MSLBmassandenergyandpressureandtemperature responseanalysisdonotmeetthemaximumcontainment pressuredesigncriteriaof44psig.Basedonthedraftdocument, acondition wasdiscovered duringplantoperation thatresultsinthenuclearpowerplant,St.LucieUnit1,beinginacondition thatisoutsidethedesignbasisoftheplant.Asaresult,thiscondition wasreportedasanon-emergency reportunder10CFR50.72(b)(1)(ii)(B),"Anyeventorcondition duringoperation thatresultsinthenuclearpowerplantbeing:'Znacondition thatisoutsidethedesignbasisoftheplant.'"Basedonthistypeofreport,theLicenseeisrequiredtosubmitanLERwithin30days.TheLERcomplieswith10CFR50.73(a)(2)(ii)(B)forreporting acondition thatisoutsidethedesignbasisoftheplant.AnalysisofSafetySignificance IThedraftMSLBcontainment analysiswassubsequently finalized andissuedtoSt.Lucie.Allconclusions inthissectionarebasedonthefinalanalysisresults.TheresultsoftheMSLBcontainment analysisdonotaffecttheTechnical Specification NRCFORM388A(8.1998)

NRCFORM366A(6-1998)LICENSEEEVENTREPORT(LER)TEXTCONTINUATION U.S.NUCLEARREGULATORY COMMISSION

~FACILITYNAME(1)St.LucieUnit1OOCKETNUMBER2)05000335LERNUMBER(6)SEQUENTIAL REVISIONNUMBERNUMBER1998-009-00PAGE(3)Page5of8TEXT(Ifmorespaceisrequired, useadditional copiesoffVRCForm3MA)(17)AnalysisofSafetySignificance (cont'd)operability ofthecontainment orrelatedsystems.Specifically, Technical Specification operability forTS3/4.6.1.2, CONTAINMENT LEAKAGE,andTS3/4.6.1.6, CONTAINMENT VESSELSTRUCTURAL INTEGRITY, arebasedonapeakcontainment pressureof39.6psigforthelimitingdesignbasisLOCA,nottheMSLB.DuringaMSLBeventthereisarelatively minorreleaseofradioactivity intothecontainment.

Also-notethatinthemorelimitingcaseforoff-sitedose,theMSLBisassumedtooccuroutsidethecontainment wherethereisadirectpathtotheenvironment.

Therefore, thelicensing basisforthecontainment operability istheLOCA,nottheMSLB.Asstatedinthepreviousparagraph, thedefinition ofcontainment operability isnotbasedontheMSLBanalysis.

However,thefunctionofthissafetyrelatedstructure canstillbeshownnottobecompromised forthere-analyzed MSLBevent.Althoughthecalculated higherevaluated peakpressureisclosertotheultimatefailureofthecontainment, significant marginabove56psigremains.TheSt.LucieIndividual PlantExamination (IPE)submittal estimates acontainment failurepressureof95pslg.Abestestimatecasewasalsoperformed byABB-CE.Thisbestestimatecaseconsidered morerealistic plantassumptions inlieuofthemoreconservative designbasisassumptions.

Specifically, themainfeedregulating valves(MFRVs)areassumedtoremainintheirpre-accident positionandbothtrainsofemergency corecoolingsystems(ECCS)areassumedtobeoperable.

Thedesignbasiscaseconservatively andnon-mechanistically assumesthatbothMFRVsgofullyopenatthebeginning oftheaccident.

Thisresultsinamuchlargerinflowoffeedwatertothefaultedgenerator thanwouldactuallyoccur.Thebestestimateassumption oftheMFRVsremaining intheirpre-accident condition isstillconservative inthatthemostlikelyresponsetothebreakwouldbefortheMFRVstoclosedowninresponsetogenerator swell.Thebestestimateassumption thatbothtrainsofECCSwouldbeavailable doesnotmeetdesignbasisrequirements forsinglefailure,butisreasonable fortheevaluated scenario.

ThemostprobablemeansofacompletelossofoneECCStrain(containment sprayandcoolers)wouldrequireaLOOPandsubsequent emergency dieselgenerator failure.BecauseaLOOPwouldgreatlyreducethepeakpressureasaresultofthereactorcoolantpumps(RCPs)andmainfeedwaterpumpstripping, aLOOPscenarioisnotlimitingforthisaccident.

Therefore, theonlyapplicable postulated failureofECCStrainswouldinvolveasingleECCScomponent.

Thesearesafetyrelatedcomponents ofhighreliability thatareextensively testedandmaintained.

Thebestestimatecaseresultsinapeakcontainment pressureof43.339psig,whichisbelowthecurrentUFSARdesignpressureof44psig.AlthoughthebestestimatecaseassumesnormalMFRVoperation andthatbothtrainsofECCSareavailable, operat'ing constraints associated withtheseparameters arenotimposedbytheassessment.

Technical Specification operability isbasedontheLOCAeventandnottheMSLBevent.Significant marginexistsbetweenthepeakcalculated MSLBpressureandanticipated failureofthecontainment.

Thebestestimatecasedemonstrates thatunderconditions thatwouldnormallybeexpected, thepeakpressurefromapostulated MSLBremainsbelowdesign.NRCFORM368AI9.1998)

NRCFORM366AIB-)998)LICENSEEEVENTREPORT(LER)TEXTCONTINUATION U.S.NUCLEARREGULATORY COMMISSION

'FACIUTYNAMEI1)St.LucieUnit1DocKETNUMBERI2)05000335LERNUMBERI6)SEQUENTIAL REVISIONNUMBERNUMBER1998-009-00PAGEI3)Page6of8TEXT/Ifmorespaceisrequired, useadditional copiesofNRCForm366AJI17)AnalysisofSafetySignificance (cont'd)St.LucieUnit1UFSARSection6.2.1.1de'scribes thedesignbasesforcontainment.

Thecontainment vesselisdesignedinaccordance withtheASMECodeSectionIII,ClassMC.Themaximuminternalpressure, asdefinedinArticleNE-3112ofthecode,is44psig.Thisvalueisdocumented inSection6.2.1.2oftheUnit1UFSAR.Thisvalueisalsodccumented intheUnit1Technical Specification designfeatures, section5.2.2.Duetothelargeinventory designsteamgenerators ofCEdesignedplants,theMSLBeventtypically producesthepeakcontainment pressureandtemperature.

However,UFSARSection6.2.1.1.b notesthattheequipment surfacetemperature islaggedandwillgenerally notexperience theelevatedtemperatures resulting fromapuresteamblowdownresponse(MSLB).Assuch,forthetemperature

response, theLOCAeventisboundingandestablishes theenvironmental qualification criteriaandtemperature limitations, asdescribed below.TheMSLBcontainment re-analysispeakcontainment pressurevalueof55.946psigistheparameter evaluated inthisLER.Containment vesselfailureischaracterized intheSt.LucieUnits1and2IPEsubmittal datedDecember1993.Specifically, AppendixG,Containment FailurePressureCharacterization, providesanassessment ofcontainment performance basedonthemethodology ofNUREG/CR-2442.

Thisassessment estimates afailurepressureof95psigfortheSt.LucieUnit1and2containment vessels.Thus,aMSLBcontainment responseanalysispeakpressureof55.946psigisboundedbytheestimated failurepressureof95psig.ItisnotedthattheLOCAcontainment analysiswasupdatedfromtheoriginalcontainment analysisforbothSt.LucieUnits1and2in1993andisdocumented intherespective UFSARs.TheMSLBcontainment re-analysis peakcontainment pressurevaluefora102percentpowerwithafailureofacontainment spraypumpanda60secondMFIVclosuretimeresultsinamaximumpeakcontainment pressureof55.946psig.Thedesignpressureforcontainment is44psig.Thedifferences intheresultsarebasedonnon-conservative assumptions intheoriginalanalysis.

Theparameters thatmostsignificantly affectedtheoutcomewerefeedwater flowrateandinitialcontainment pressureandhumidity.

Intheoriginalanalysis, thefeedwater flowratetothefaultedsteamgenerator wasassumedtoramplinearlyfor60secondMFIVclosure.TheMFIVsaregatevalves;therefore, thisassumption wouldbenon-conservative.

Aconservative approachwouldconsiderthisassumption asastepchangeintheflowrateat60seconds.Theinitialcontainment pressurewasassumedtobe14.7psia.Technical Specification 3.6.1.4allowsforaninternalrangeofpressures andpermitsacontainment pressureofhigherthan14.7psia.ThehighervalueisassumedfortherevisedMSLBaccidentanalysis.

Containment initialhumidity, althoughnotaTechnical Specification, cannon-conservatively impactpeakcontainment pressureifnotaccounted for.Theoriginalassumptions, therefore, weredetermined tocontainsomenon-conservatisms thatresultedinhigherthanexpectedpeakcontainment pressurewhenre-analyzed.

NRCFORM3BBAIB.1888)

NRCFOAM366A(6.'I998)4lLlCENSEEEVENTREPORT(LER)TEXTCONTINUATION U.S.NUCLEARREGULATORY COMMISSION

~FACILITYNAME(1)St.Lucie'nit 1DOCKETNUMBER205000335LERNUMBER(6)SEQUENTIAL REVISIONNUMBERNUMBER1998-009.-00PAGE(3)Page7of8TEXTllfmorespeceisrequired, useedditionel copiesofNRCForm366AI(17)AnalysisofSafetySignificance (cont'd)Theresultofthisre-analysis demonstrates apotential needforareduction infeedwater massadditiontocontainment forUnit1.Manyengineering solutions canbeconsidered, including modification oftheMFIVclosuretimes.Afasterresponseinclosuretime,suchasintheUnit2design,clearlybenefitsinincreased margintothedesignlimitof44psig.Abestestimate102%powercasewithsafeguards available isprovidedintheABB-CEcalculation.

Case2oftheMSLBcontainment responsecreditsnormaloperation ofthemainfeedwater regulating valvesandutilizesrealistic inputdata.Theresultsofthiscasedemonstrate apeakcontainment pressureof43.339psig.Thisvalueisbelowthecontainment designvalueof44psig.Althoughthiscaseisnotaboundingcaseforanalysisconsideration, itdemonstrates thatpressures remainbelowdesignforaMSLBmassandenergyreleaseinsidecontainment withrealistic inputassumptions.

Thisevaluated caseprovidespartofthebasesforoperability ofUnit1containment.

TheMSLBanalysisispostulated toreachapeaktemperature ofapproximately 375Fat42.2seconds.Ztwasidentified that11ofthe37in-containment EQDocPacsenvelopthe375Fpostulated peaktemperature.

Section4.3ofEQDocPac2998-A-451-1000 (page1000-4-5) hasadiscussion ofthermal.lagfortheUnit2insidecontainment MSLB,andconcludes thattheactualtemperature experienced bycomponents areboundedbythecontainment LOCAtemperature profiles.

TheseUnit2resultsareapplicable fortheUnit1in-containment EQDocPacsthatarenotenveloped bythe375Ftemperature peak.Figures4-5and4-6oftheDocPacshowatypicalinstrument cableandRosemount transmitter andthetemperature lagfor.045inchesbelowthesurfaceofthecable(typicalthickness ofacablejacket)andthesurfacetemperature ofthetransmitter whenexposedtoatypicalMSLBprofile.Theseitemsconservatively represent alloftheEQequipment thatwouldbeexposedtoanin-containment MSLB.Fromtheplotofthesurfacetemperature ofthecableinFigure4-6oftheDocPac,thepeaktemperature isapproximately 385Fat45secondsenveloping thepostulated peakforUnit1.Theplotsofthetransmitter surfacetemperature andat.045belowthesurfaceofthecable(atthecableinsulation),

showsthatthetemperature ofthetransmitter reachesapproximately 245Fandtheinsulation ofthecablejustbarelyexceeds260F.Sincebothofthesetemperatures arebelowtheUnit1LOCAtemperature of270F,thequalification oftheEQequipment willnotbeadversely affectedandwouldremainoperable.

Thedoseconsequences foraMSLBinsidecontainment areboundedbytheMSLBoutsidecontainment andtheLOCAevent.Technical Specification operability isbasedontheLOCA,nottheMSLBevent.Furthermore, significant marginexistsabovetheNRCFORM388AI8.1998)

NRCFORM366A(8.1998)LICENSEEEVENTREPORT(LER)TEXTCONTINUATION U.S.NUCLEARREGULATORY COMMISSION

~FACILITYNAME(1)St.LucieUnit1DOCKETNUMBERI205000335LERNUMBER(6)SEQUENTIAL REVISIONNUMBERNUMBER1998-009-00PAGE(3)Page8of8TEXT/ifmorespaceisrequired, useadditional copiesofNRCForm3MA)I17)AnalysisofSafetySignificance (cont'd)calculated MSLBcontainment analysispeakpressuretoensurethatthecontainment wouldnotfailasaresultofaMSLBinsidecontainment.

Bestestimateanalysisdemonstrates thatundermoreprobableconditions thecurrentdesignpressureof44psigwillnotbeexceeded.

Basedontheseconsiderations, nooperability concernexistsfortheconditions statedinthisLBR,andcontinued plantoperation posesnoadverserisktothehealthandsafetyofthepublic.Corrective Actions1.Longtermcorrective actionwillconsistofeithermodifications toreducefeedwaterflowtothefaultedgenerator orachangetothelicensing basisoftheMSLBpeakcontainment pressuretoavalueofgreaterthan56psig.2.Thelowtemperature overpressureLTOPanalysiswasidentified asnothavingbeenre-runsinceoriginallicenseandiscurrently beingre-baselined.3.St.Luciewillreviewthegenericimplications ofsimilarsignificant differences (similartothedifference inMFZVclosuretime)insafetyrelatedsystems/components betweenthetwounits.OtherInformation NoneNoneNRCFORM388A(81998)

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