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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 | |||
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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 | |||
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) | |||
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) | |||
,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) | |||
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) | |||
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) | |||
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) | |||
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 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) | |||
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) | |||
}} | }} |
Revision as of 12:44, 25 April 2018
ML17229A990 | |
Person / Time | |
---|---|
Site: | Saint Lucie ![]() |
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) | |
Text
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
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
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)
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)
,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)
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)
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)
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)
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 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)
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)