ML16242A156

LER 16-006-00 for Grand Gulf, Unit 1, Regarding Multiple Valid Engineered Safety Feature Actuations

ML16242A156
Person / Time
Site:	Grand Gulf
Issue date:	08/29/2016
From:	Nadeau J Entergy Operations
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
GNRO-2016/00044 LER 16-006-00
Download: ML16242A156 (6)

Text

GNRO-2016/00044 August29,2016 U.S.Nuclear Regulatory Commission Attn: DocumentControlDesk Washington,DC20555-0001 Entergy Operations, Inc.P.o.Box 756PortGibson,MS 39150JamesNadeauManager,Regulatory AssuranceGrandGulfNuclearStation Tel.(601)437-2103

SUBJECT:

LicenseeEventReport(LER) 2016-006-00,MultipleValid Engineered Safety Feature Actuations Grand Gulf NuclearStation,Unit1DocketNo.50-416LicenseNo.NPF-29

DearSirorMadam:

AttachedisLicenseeEventReport(LER) 2016-006-00,whichwillbe supplemented uponcompletionofthe in-progressrootcauseevaluation.Thisreportis submitted in accordance withTitle10CodeofFederal Regulations 50.73(a)(2)(iv)(A).Thislettercontainsnonew Regulatory Commitments.Ifyouhaveany questionsorrequireadditional information,pleasecontactJamesNadeauat601-437-2103.

JJN/sas

Attachment:

LicenseeEventReport(LER) 2016-006-00cc:(SeeNextPage)

GNRO-20 16/00044Page2of2cc:U.S.Nuclear Regulatory CommissionATTN:Mr.JimKim, NRR/DORL (w/2)MailStop OWFN8B1Rockville,MD 20852-2738 U.S.Nuclear Regulatory CommissionATTN:Mr.KrissM.

Kennedy (w/2)Regional Administrator,RegionIV1600EastLamar BoulevardArlington,TX76011-4511Mr.B.J.Smith(w/2)Director,Divisionof Radiological HealthMississippiState DepartmentofHealthDivisionof Radiological Health3150Lawson Street Jackson,MS39213 NRC Senior Resident InspectorGrandGulf Nuclear StationPortGibson,MS39150 AttachmenttoGNRO 2016/00044LicenseeEventReport(LER) 2016-006-00 NRCFORM366 U.S.NUCLEAR REGULATORY COMMISSIONAPPROVEDBYOMB:NO.3150-0104EXPIRES:10/31/2018 (11-2015)Estimatedburdenperresponsetocomplywiththismandatorycollection V'-R REGO(request:80hours.Reportedlessonslearnedareincorporatedintothe

.::;v" ,,/" LICENSEEEVENTREPORT(LER)licensingprocessandfedbacktoindustry.Sendcommentsregardingburden......(Seereverseforrequired number ofestimatetothe FOINPrivacySection(T-5F53),U.S.NuclearRegulatory

!('lCommission,Washington,DC20555-0001,orbyinternete-mailto

..: 0<digits/charactersforeachblock)infocollects.resource@nrc.gov,andtotheDeskOfficer,OfficeofInformation

...Y:andRegulatoryAffairs,NEOB-10202,(3150-0104),OfficeofManagement o" i.?andBudget,Washington,DC20503.Ifameansusedtoimposean

....,."'?informationcollectiondoesnotdisplayacurrentlyvalidOMBcontrolnumber,"'....theNRCmaynotconductorsponsor,andapersonisnotrequiredtorespondto,theinformationcollection.

1.FACILITY NAME 2.DOCKET NUMBER 13.PAGEGrandGulfNuclearStation,Unit1 050004161OF34.TITLEMultipleValidEngineeredSafetyFeatureActuations5.EVENTDATE6.LER NUMBER7.REPORTDATE8.OTHER FACILITIES INVOLVED YEAR I SEQUENTIAL I REV MONTHFACILITYNAMEDOCKETNUMBER MONTH DAY YEARNUMBERNO.DAYYEAR N/A05000N/AJune302016 2016-006-00 08 29 2016FACILITYNAMEDOCKETNUMBER N/A05000N/A 9.OPERATINGMODE11.THISREPORTIS SUBMITTED PURSUANTTOTHE REQUIREMENTSOF10CFR§: (Checkallthat apply)4 o20.2201(b) o 20.2203(a)(3)(i) o 50.73(a)(2)(i)(C) o 50.73(a)(2)(vii) o20.2201(d) o 20.2203(a)(3)(ii) o 50.73(a)(2)(ii)(A) o 50.73(a)(2)(viii)(A) o 20.2203(a)(1) o 20.2203(a)(4) o 50.73(a)(2)(ii)(B) o 50.73(a)(2)(viii)(B) o 20.2203(a)(2)(i) o50.36(c)(1)(i)(A) o 50.73(a)(2)(iii) o 50.73(a)(2)(ix)(A)10.POWER LEVEL o 20.2203(a)(2)(ii) o50.36(c)(1)(ii)(A)50.73(a)(2)(iv)(A) o 50.73(a)(2)(x) 0 o 20.2203(a)(2)(iii) o 50.36(c)(2) o 50.73(a)(2)(v)(A) o73.71(a)(4) o 20.2203(a)(2)(iv) o 50.46(a)(3)(ii) o 50.73(a)(2)(v)(B) o73.71(a)(5) o 20.2203(a)(2)(v) o 50.73(a)(2)(i)(A) o 50.73(a)(2)(v)(C) o OTHER o 20.2203(a)(2)(vi) o 50.73(a)(2)(i)(B) o 50.73(a)(2)(v)(D)SpecifyinAbstractbeloworinNRCForm366A 12.LICENSEE CONTACTFORTHISLERFACILITYNAME I TELEPHONE NUMBER(IncludeAreaCode)JamesNadeau/Manager,Regulatory Assurance (601)437-2103 13.COMPLETEONELINEFOREACH COMPONENT FAILURE DESCRIBEDINTHISREPORTCAUSESYSTEM COMPONENTMANU-REPORTABLECAUSESYSTEM COMPONENT MANU-REPORTABLEFACTURERTOEPIX FACTURERTOEPIX N/A N/A N/A N/A N/AN/AN/AN/A N/A N/A 14.SUPPLEMENTAL REPORT EXPECTED 15.EXPECTED MONTHDAYYEAR SUBMISSION 11 17 2016[8J YES(Ifyes, complete 15.EXPECTED SUBMISSION DA TE)DNO DATE ABSTRACT(Limitto1400spaces,i.e., approximately 15 single-spacedtypewrittenlines)OnJune30,2016at1715CDT,GrandGulfNuclearStation(GGNS) experiencedanelectricalpowersupplylossfrom Service Transformer21whichresultedinpowersupplybeinglosttoDivision2(16ABBus)andDivision3(17ACBus)ESFbuses.ThisresultedinavalidactuationofDivision2andDivision3Diesel Generatorsonbusundervoltage.They both automaticallystartedandenergizedtheirrespectiveESFbusesasdesigned.Duringthisevent,thelossofpowertotheDivision2(16ABBus)resultedinaDivision2RPSbuspowerloss,whichactuatedaDivision2RPShalfSCRAM signal.Thepowerlossalsoresultedinalossofthe InstrumentAirpressureresultinginsomeControlRodScramValvestodriftopen.ThisinturncausedtheScramDischargeVolumetofilltothepointwhereaDivision1RPShalfSCRAMsignalwasinitiatedfromScramDischargeVolumelevelhighonChannel'A'.ThisresultedinavalidfullRPSReactorSCRAMwhilenotcritical.InstrumentAirpressurewasrestoredandtheSCRAMsignalwasresetat1733CDT.

Appropriateoffnormaleventprocedureswereenteredtomitigatethetransient.Allsafety systemsperformedasexpected.ThedirectcausewasafaultedCphase34.5kVService TransformerpowersupplycabletotheBOP23Transformer.Atemporarythreephaseoverheadlinewasinstalledtobypassthefaulted34.5kVcablesection.

APPROVEDBYOMB:NO.

3150-0104EXPIRES:10/31/2018Estimatedburdenperresponsetocomplywiththismandatorycollectionrequest:80hours.Reportedlessonslearnedare incorporatedintothelicensingprocessandfedbacktoindustry.SendcommentsregardingburdenestimatetotheFOIA,PrivacyandInformationCollectionsBranch (l-5F53),U.S.NuclearRegulatoryCommission,Washington,DC20555-0001,orbyinternete-mailto Infocoliects.Resource@nrc.gov,andtotheDeskOfficer,OfficeofInformationandRegulatoryAffairs,NEOB-10202,(3150-0104),OfficeofManagementandBudget,Washington,DC20503.IfameansusedtoimposeaninformationcollectiondoesnotdisplayacurrentlyvalidOMBcontrolnumber,theNRCmaynotconductorsponsor,andapersonisnotrequiredtorespondto,theinformationNRCFORM (11-2015)366AU.S.NUCLEAR REGULATORY COMMISSION LICENSEE EVENT REPORT (LER)CONTINUATION SHEET collection.Page2of3 1.FACILITY NAMEGrandGulf NuclearStation,Unit1 NARRATIVE 2.DOCKET 05000416 YEAR I3.LER NUMBER SEQUENTIAL NUMBER 2016-006-00 I REV.NO.PLANT CONDITIONSPRIORTOTHEEVENTAtthetimeoftheevent,GrandGulfNuclearStation(GGNS)Unit1wasinMode4,ColdShutdown,withMainSteamIsolationValves(MSIVs)[SB]closed.Reactor WaterLevelwas maintainedinthenormalwaterlevelbandbytheControlRodDriveSystem(CRDS)[AA].ResidualHeatRemoval(RHR)A[BO]wasmaintainedinShutdownCoolingoperationanditwasnotaffectedbythisevent.

DESCRIPTIONOnJune30,2016at17:15,GrandGulfNuclearStation experiencedanelectricalpowersupplylossfromService Transformer21(ST21)[XFMR]whichresultedin powersupplybeinglosttoDivision2(16ABBus)andDivision3(17ACBus)EngineeredSafetyFeature(ESF)buses[BU].ThisresultedinavalidactuationofDivision2andDivision3StandbyDiesel Generators(SDGs)[EK]onunder-voltage.BothSDGs automaticallystartedandenergizedtheirrespectiveESFbusesasdesigned.Duringthisevent,thelossofpowertotheDivision2(16ABbus)resultedinaDivision2ReactorProtectionSystem(RPS)[JE]buspowerloss,whichactuatedaDivision2RPShalfSCRAMsignal.TheDivision2powerlossalsoresultedinalossofInstrumentAirpressureresultinginsomeControlRodScramValvestodriftopen.ThisinturncausedtheScramDischargeVolumetofilltothepointwhereaDivision1RPShalfSCRAMsignalwasinitiatedfromScramDischargeVolumelevelhighonChannelA.ThisresultedinavalidfullRPSReactorSCRAMwhilenotcritical.

InstrumentAirpressurewasrestoredandtheSCRAMsignalwasresetat1733hrs.Appropriateoffnormaleventprocedureswereenteredtomitigatethetransient.NoECCS[BM]initiationsignalswerereached.Allsafetysystemsperformedasexpected.

REPORTABILITYEventNotificationNo.52057wasmadetotheNRC OperationsCenter.ThisLERisbeingsubmittedpursuanttoTitle10CodeofFederalRegulations10CFR 50.73(a)(2)(iv)(A)fortheactuationofEngineeredSafetyFeatures.TelephonicnotificationwasmadetotheU.S.

Nuclear Regulatory Commission (NRC)Emergency NotificationSystemonJune30,2016,within8hoursoftheevent,pursuantto10CFR 50.72(b)(3)(iv)formultiplevalidspecifiedsystemactuations.

CAUSEDirectCause:AfaultedCphase34.5kVService Transformer21powersupplycabletotheBOP23 Transformerresultinginthelossofpowertothe21Rbus.ApparentCause:InvestigationoftheApparentCauseispngoing.A supplementalreporttothisLERwillbeprovidedupon completionoftheApparentCause investigation APPROVEDBYOMB:NO.3150-0104EXPIRES:10/31/2018Estimatedburdenperresponsetocomplywiththismandatorycollectionrequest:80hours.Reportedlessonslearnedareincorporatedintothelicensingprocessandfedbacktoindustry.SendcommentsregardingburdenestimatetotheFOIA,PrivacyandInformationCollectionsBranch(T-5F53),U.S.NuclearRegulatoryCommission,Washington,DC20555-0001,orbyinternete-mailto Infocoliects.Resource@nrc.gov,andtotheDeskOfficer,OfficeofInformationandRegulatoryAffairs,NEOB-10202,(3150-0104),OfficeofManagementandBudget,Washington,DC20503.IfameansusedtoimposeaninformationcollectiondoesnotdisplayacurrentlyvalidOMBcontrolnumber,theNRCmaynotconductorsponsor,andapersonisnotrequiredtorespondto,theinformationNRCFORM (11-2015)366AU.S.NUCLEAR REGULATORY COMMISSION LICENSEE EVENT REPORT (LER)CONTINUATION SHEET collection.Page3of3 1.FACILITY NAMEGrandGulf NuclearStation,Unit1 NARRATIVECORRECTIVEACTIONS 2.DOCKET 05000416 YEAR I3.LER NUMBER SEQUENTIAL NUMBER 2016-006-00 I REV.NO.Temporarilyinstalledathreephaseoverheadline,tobypassthefaulted34.5kVcablesection.

SAFETY SIGNIFICANCETheeventposednothreattothehealthandsafetyofthegeneralpublicorto nuclearsafetyassystemsperformedasdesigned.No Technical Specificationsafetylimitswereviolated.Industrialsafetywasnotchallenged,andtherewasnopotentialoractualradiologicalreleaseduringtheevent.PREVIOUSSIMILAREVENTSPrevioussimilareventswillbe discussedinthe supplementalreportuponcompletionoftheApparentCause investigation.