ML17086A175

LER 16-006-01 for Grand Gulf, Unit 1, Regarding Multiple Valid Engineered Safety Feature Actuations

ML17086A175
Person / Time
Site:	Grand Gulf
Issue date:	03/27/2017
From:	Nadeau J J Entergy Operations
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
GNRO-2016/00057 LER 16-006-01
Download: ML17086A175 (6)

Text

• GNRO-2016/00057March27,2017U.S.NuclearRegulatoryCommissionAttn:DocumentControlDeskWashington,DC20555-0001EntergyOperations,Inc.P.O.Box756PortGibson,MS39150JamesNadeauManager,RegulatoryAssuranceGrandGulfNuclearStationTel.(601)437-2103

SUBJECT:

LicenseeEventReport(LER)2016-006-01,MultipleValidEngineeredSafetyFeatureActuationsGrandGulfNuclearStation,Unit1DocketNo.50-416LicenseNo.NPF-29

DearSirorMadam:

AttachedisLicenseeEventReport(LER)2016-006-01,asupplementtoLER2016-006-00,whichwassubmittedtotheUSNuclearRegulatoryCommission(NRC)onAugust29,2016.TheoriginalLERreportedthatonJune30,2016,GrandGulfNuclearStation(GGNS)experiencedanelectricalpowersupplylossthatresultedinEngineeredSafetyFeatureactuations.TheeventswerereportableunderTitle10CodeofFederalRegulations50.73(a)(2)(iv)(A)foranyeventorconditionthatresultedinmanualorautomaticactuationofEngineeredSafetyFeatures.BecausetheApparentCauseEvaluationhadnotbeencompletedatthetimetheoriginalLERwassubmitted,thissupplementisbeingsubmittedinaccordancewithNUREG-1022,revision3,Section5.1.5,"SupplementalInformationandrevisedLERs."ItcontainsthefinalcausesandcorrectiveactionsasdeterminedbytheApparentCauseEvaluation.ThislettercontainsnonewRegulatoryCommitments.Ifyouhaveanyquestionsorrequireadditionalinformation,pleasecontactJamesNadeauat601-437-2103.Sincerely,4j/tLrJJN/sas(7U;<<

Attachment:

LicenseeEventReport(LER)2016-006-01 GNRO-2016/00057Page2of2cc:U.S.NuclearRegulatoryCommissionATTN:Mr.SivaLingam,NRR/DORL(w/2)MailStopOWFN8B111555RockvillePikeRockville,MD20852-2738U.S.NuclearRegulatoryCommissionATTN:Mr.KrissM.Kennedy(w/2)RegionalAdministrator,RegionIV1600EastLamarBoulevardArlington,TX76011-4511U.S.NuclearRegulatoryCommissionATTN:Mr.KrissM.Kennedy,NRR/DORL(w/2)RegionalAdministrator,RegionIV1600EastLamarBoulevardNRCSeniorResidentInspectorGrandGulfNuclearStationPortGibson,MS39150 AttachmenttoGNRO2016/00057LicenseeEventReport(LER)2016-006-01 NRCFORM366U.S.NUCLEARREGULATORYCOMMISSIONAPPROVEDBYOMB:NO.3150-0104EXPIRES:10/31/2018(11-2015)EstimatedburdenperresponsetocomplywiththismandatorycollectionAEGV(request:80hours.Reportedlessonslearnedareincorporatedintothe¢Ie,\..,,..LICENSEEEVENTREPORT(LER)licensingprocessandfedbacktoindustry.Sendcommentsregardingburden4:t"...(SeereverseforrequirednumberofestimatetotheFOIAIPrivacySection(T-5F53),U.S.NuclearRegulatory::!("lCommission,Washington,DC20555-0001,orbyinternete-mailto0<digits/charactersforeachblock)infocollects.resource@nrc.qov,andtotheDeskOfficer,OfficeofInformation.'c:<n£:'andRegulatoryAffairs,NEOB-10202,(3150-0104),OfficeofManagement<'i;'-"""*'andBudget,Washington,DC20503.Ifameansusedtoimposean",0informationcollectiondoesnotdisplayacurrentlyvalidOMBcontrolnumber,......theNRCmaynotconductorsponsor,andapersonisnotrequiredtorespondto,theinformationcollection.1.FACILITYNAME2.DOCKETNUMBER13.PAGEGrandGulfNuclearStation,Unit1050004161OF34.TITLEMultipleValidEngineeredSafetyFeatureActuations5.EVENTDATE6.LERNUMBER7.REPORTDATE8.OTHERFACILITIESINVOLVEDMONTHDAYYEARYEARISEQUENTIALIREVMONTHFACILITYNAMEDOCKETNUMBERNUMBERNO.DAYYEARN/A05000N/A063020162016-006-0103272017FACILITYNAMEDOCKETNUMBERN/A05000N/A9.OPERATINGMODE11.THISREPORTISSUBMITTEDPURSUANTTOTHEREQUIREMENTSOF10CFR§:(Checkallthatapply)4D20.2201(b)D20.2203(a)(3)(i)D50.73(a)(2)(i)(C)D50.73(a)(2)(vii)D20.2201(d)D20.2203(a)(3)(ii)D50.73(a)(2)(ii)(A)D50.73(a)(2)(viii)(A)D20.2203(a)(1)D20.2203(a)(4)D50.73(a)(2)(ii)(B)D50.73(a)(2)(viii)(B)D20.2203(a)(2)(i)D50.36(c)(1)(i)(A)D50.73(a)(2)(iii)D50.73(a)(2)(ix)(A)10.POWERLEVELD20.2203(a)(2)(ii)D50.36(c)(1)(ii)(A)[gI50.73(a)(2)(iv)(A)D50.73(a)(2)(x)0D20.2203(a)(2)(iii)D50.36(c)(2)D50.73(a)(2)(v)(A)D73.71(a)(4)D20.2203(a)(2)(iv)D50.46(a)(3)(ii)D50.73(a)(2)(v)(B)D73.71(a)(5)D20.2203(a)(2)(v)D50.73(a)(2)(i)(A)D50.73(a)(2)(v)(C)DOTHERD20.2203(a)(2)(vi)D50.73(a)(2)(i)(B)D50.73(a)(2)(v)(D)SpecifyinAbstractbeloworinNRCForm366A12.LICENSEECONTACTFORTHISLERFACILITYNAMEITELEPHONENUMBER(IncludeAreaCode)JamesNadeau/Manager,RegulatoryAssurance(601)437-210313.COMPLETEONELINEFOREACHCOMPONENTFAILUREDESCRIBEDINTHISREPORTCAUSESYSTEMCOMPONENTMANU-REPORTABLECAUSESYSTEMCOMPONENTMANU-REPORTABLEFACTURERTOEPIXFACTURERTOEPIXN/AN/AN/AN/AN/AN/AN/AN/AN/AN/A14.SUPPLEMENTALREPORTEXPECTED15.EXPECTEDMONTHDAYYEARSUBMISSIONN/AN/AN/ADYES(Ifyes,complete15.EXPECTED-SUBMISSIONDATE)[gINODATEABSTRACT(Limitto1400spaces,i.e.,approximately15single-spacedtypewrittenlines)OnJune30,2016at1715COT,GrandGulfNuclearStation(GGNS)experiencedanelectricalpowersupplylossfromServiceTransformer21whichresultedinpowersupplybeinglosttoDivision2(16ABBus)andDivision3(17ACBus)ESFbuses.ThisresultedinavalidactuationofDivision2andDivision3DieselGeneratorsonbusundervoltage.TheybothautomaticallystartedandenergizedtheirrespectiveESFbusesasdesigned.Duringthisevent,thelossofpowertotheDivision2(16ABBus)resultedinaDivision2RPSbuspowerloss,whichactuatedaDivision2RPShalfSCRAMsignal..ThepowerlossalsoresultedinalossoftheInstrumentAirpressureresultinginsomeControlRodScramValvestodriftopen.ThisinturncausedtheScramDischargeVolumetofilltothepointwhereaDivision1RPShalfSCRAMsignalwasinitiatedfromScramDischargeVolumelevelhighonChannel'A'.ThisresultedinavalidfullRPSReactorSCRAMwhilenotcritical.InstrumentAirpressurewasrestoredandtheSCRAMsignalwasresetat1733COT.Appropriateoffnormaleventprocedureswereenteredtomitigatethetransient.Allsafetysystemsperformedasexpected.TheDirectCausewasafailureofthetapedinsulationonthe'C'phase34.5kVServiceTransformerpowersupplycabletotheBOP23Transformer.TheApparentCausewasanoutertapewrapinsulationfailurethatleftamoisturepathbetweenthebraid,connectingthesplice,andthecenterconductor.Atemporarythreephaseoverheadlinewasinstalledtobypassthefaulted34.5kVcablesection.Aplannedcorrectiveactiontoinstallapermanentundergroundreplacementwasgenerated.

APPROVEDBYOMB:NO.3150-0104EXPIRES:10/31/2018Estimatedburdenperresponsetocomplywiththismandatorycollectionrequest:80hours.Reportedlessonslearnedareincorporatedintothelicensingprocessandfedbacktoindustry.SendcommentsregardingburdenestimatetotheFOIA,PrivacyandInformationCollectionsBranch(T-5F53),U.S.NuclearRegulatoryCommission,Washington,DC20555-0001,orbyinternete-mailtoInfocoliects.Resource@nrc.gov,andtotheDeskOfficer,OfficeofInformationandRegulatoryAffairs,NEOB-10202,(3150-0104),OfficeofManagementandBudget,Washington,DC20503.IfameansusedtoimposeaninformationcollectiondoesnotdisplayacurrentlyvalidOMBcontrolnumber,theNRCmaynotconductorsponsor,andapersonisnotrequiredtorespondto,theinformationNRCFORM(11-2015)366AU.S.NUCLEARREGULATORYCOMMISSIONLICENSEEEVENTREPORT(LER)CONTINUATIONSHEETcollection.Page2of31.FACILITYNAMEGrandGulfNuclearStation,Unit1NARRATIVE2.DOCKET05000416YEARI3.LERNUMBERSEQUENTIALNUMBER2016-006-01IREV.NO.PLANTCONDITIONSPRIORTOTHEEVENTAtthetimeoftheevent,GrandGulfNuclearStation(GGNS)Unit1wasinMode4,ColdShutdown,withMainSteamIsolationValves(MSIVs)[SB]closed.ReactorWaterLevelwasmaintainedinthenormalwaterlevelbandbytheControlRodDriveSystem(CRDS)[AA].ResidualHeatRemoval(RHR)A[BO]wasmaintainedinShutdownCoolingoperationanditwasnotaffectedbythisevent.DESCRIPTIONOnJune30,2016at17:15,GrandGulfNuclearStationexperiencedanelectricalpowersupplylossfromServiceTransformer21(ST21)[XFMR]whichresultedinpowersupplybeinglosttoDivision2(16ABBus)andDivision3(17ACBus)EngineeredSafetyFeature(ESF)buses[BU].ThisresultedinavalidactuationofDivision2andDivision3StandbyDieselGenerators(SDGs)[EK]onunder-voltage.BothSDGsautomaticallystartedandenergizedtheirrespectiveESFbusesasdesigned.Duringthisevent,thelossofpowertotheDivision2(16ABbus)resultedinaDivision2ReactorProtectionSystem(RPS)[JE]buspowerloss,whichactuatedaDivision2RPShalfSCRAMsignal.TheDivision2powerlossalsoresultedinalossofInstrumentAirpressureresultinginsomeControlRodScramValvestodriftopen.ThisinturncausedtheScramDischargeVolumetofilltothepointwhereaDivision1RPShalfSCRAMsignalwasinitiatedfromScramDischargeVolumelevelhighonChannelA.ThisresultedinavalidfullRPSReactorSCRAMwhilenotcritical.InstrumentAirpressurewasrestoredandtheSCRAMsignalwasresetat1733hrs.Appropriateoffnormaleventprocedureswereenteredtomitigatethetransient.NoEmergencyCoreCoolingSystem(ECCS)[BM]initiationsignalswerereached.Allsafetysystemsperformedasexpected.REPORTABILITYEventNotificationNo.52057wasmadetotheNRCOperationsCenter.ThisLERisbeingsubmittedpursuanttoTitle10CodeofFederalRegulations10CFR50.73(a)(2)(iv)(A)fortheactuationofEngineeredSafetyFeatures.TelephonicnotificationwasmadetotheU.S.NuclearRegulatoryCommission(NRC)EmergencyNotificationSystemonJune30,2016,within8hoursoftheevent,pursuantto10CFR50.72(b)(3)(iv)formultiplevalidspecifiedsystemactuations.CAUSETheDirectCausewasafailureofthetapedinsulationonthe'C'phase34.5kVServiceTransformer21powersupplycabletotheBOP23Transformer.TheApparentCausewasanoutertapewrapinsulationfailurebetweenthebraid,connectingthesplice,andthecenterconductor.Disassemblyandvisualinspectionofthecablespliceshowedthattheinsulationhadvoidsandamoisturepaththroughthesplitintheoutertapewrap.

APPROVEDBYOMB:NO.3150-0104EXPIRES:10/31/2018Estimatedburdenperresponsetocomplywiththismandatorycollectionrequest:80hours.Reportedlessonslearnedareincorporatedintothelicensingprocessandfedbacktoindustry.SendcommentsregardingburdenestimatetotheFOIA,PrivacyandInformationCollectionsBranch(T-5F53),U.S.NuclearRegulatoryCommission,Washington,DC20555-0001,orbyinternete-mailtoInfocoliects.Resource@nrc.gov,andtotheDeskOfficer,OfficeofInformationandRegulatoryAffairs,NEOB-10202,(3150-0104),OfficeofManagementandBudget.Washington,DC20503.IfameansusedtoimposeaninformationcollectiondoesnotdisplayacurrentlyvalidOMBcontrolnumber,theNRCmaynotconductorsponsor,andapersonisnotrequiredtorespondto,theinformationNRCFORM(11-2015)366AU.S.NUCLEARREGULATORYCOMMISSIONLICENSEEEVENTREPORT(LER)CONTINUATIONSHEETcollection.Page3of31.FACILITYNAMEGrandGulfNuclearStation,Unit1NARRATIVECORRECTIVEACTIONS2.DOCKET05000416YEARI3.LERNUMBERSEQUENTIALNUMBER2016-006-01IREV.NO.IAtemporarythreephaseoverheadlinewasinstalledtobypassthefaulted34.5kVcablesection.Acorrectiveaction,toinstallapermanentundergroundreplacement,isplannedforApril2018.SAFETYSIGNIFICANCETheeventposednothreattothehealthandsafetyofthegeneralpublicortonuclearsafetyassystemsperformedasdesigned.NoTechnicalSpecificationsafetylimitswereviolated.Industrialsafetywasnotchallenged,andtherewasnopotentialoractualradiologicalreleaseduringtheevent.PREVIOUSSIMILAREVENTSTheINPOICESsearchtoolwasusedtofindindustryOperatingExperiencesimilartothisevent.ThesearchidentifiedcablefailuresandpartiallossofoffsitepoweratbothGrandGulfandotherstations.Therewerenospecificlearningshoweverthatwouldhavehelpedtopreventthisevent.