ML13273A354

LER 13-003-00 for Grand Gulf Nuclear Station, Unit 1 Regarding Reactor Protection System and Reactor Core Isolation Cooling Actuation Due to a High Reactor Pressure Transient

ML13273A354
Person / Time
Site:	Grand Gulf
Issue date:	09/26/2013
From:	Richey M L Entergy Operations
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
GNRO-2013/00054 LER 13-003-00
Download: ML13273A354 (7)

Text

EntergyOperations, Inc.P.O.Box756PortGibson,MS39150MartyL.RicheyActingDirector, NuclearSafetyAssurance GrandGulfNuclearStationTel.(601)437-6787GNRO-2013/00054 September 26,2013U.S.NuclearRegulatory Commission Attn:DocumentControlDeskWashington, DC20555-0001

DearSirorMadam:

LicenseeEventReport2013-003-00 ReactorProtection SystemandReactorCoreIsolation CoolingActuation DuetoaHighReactorPressureTransient GrandGulfNuclearStation,Unit1DocketNo.50-416LicenseNo.NPF-29AttachedisLicenseeEventReport2013-003-00, whichisafinalreport.Thisreportissubmitted inaccordance withTitle10CodeofFederalRegulations 50.73(a)(2)(iv)(A).

Thislettercontainsnonewcommitments.

Ifyouhaveanyquestions orrequireadditional information, pleasecontactMr.Christopher R.Robinsonat(601)437-7326.

Sincerely, rcpMLRlslw\

Attachment:

LicenseeEventReport(LER)2013-003-00 cc:(seenextpage)

GNRO-2013/00054 Page2of2cc:U.S.NuclearRegulatory Commission ATTN:Mr.StevenA.ReynoldsActingRegionalAdministrator, RegionIV1600EastLamarBoulevard Arlington, TX76011-4511 U.S.NuclearRegulatory Commission AnN:Mr.AlanWang,NRRlDORLMailStopOWFN/8B1Washington, DC20555-0001 NRCSeniorResidentInspector GrandGulfNuclearStationPortGibson,MS39150 Attachment toGNRO=2013/00054 LicenseeEventReport(LER)2013-003-00 NRCFORM366U.S.NUCLEARREGULATORY COMMISSION APPROVEDBYOMB:NO.3150-0104 EXPIRES:10/31/2013 LICENSEEEVENTREPORT(LER)(Seereverseforrequirednumberofdigits/characters foreachblock)1.FACILITYNAMEGrandGulfNuclearStation,Unit1theNRCrespondto,2.DOCKETNUMBER050004163.PAGE1OF44.TITLEReactorProtection SystemandReactorCoreIsolation CoolingActuation DuetoaHighReactorPressureTransient 5.EVENTDATE6.LERNUMBER7.REPORTDATE8.OTHERFACILITIES INVOLVEDMONTHDAYYEARYEARSEQUENTIAL REVMONTHDAYYEARFACILITYNAMEN/ANUMBERNO.N/A073020132013-003-00 09262013N/AN/A9.OPERATING MODE11.THISREPORTISSUBMITTED PURSUANTTOTHEREQUIREMENTS OF10CFR§:(Checkallthatapply)110010.POWERLEVEL20.2201(b)20.2203{a)(3){i) 50.73(a){2){i){C) 50.73(a)(2){vii) o20.2201{d) 20.2203{a){3){ii)

D50.73{a)(2)(ii)(A)

D50.73(a){2)(viii)(A) o20.2203(a){1)

D20.2203(a){4) 50.73{a)(2){ii)(B)

D50.73{a)(2){viii)(B) 1----------1 D20.2203(a)(2){i)

D50.36(c)(1)(i)(A)

D50.73(a)(2){iii)

D50.73(a)(2){ix)(A) o20.2203(a){2)(ii)

D50.36(c)(1)(ii)(A) 50.73(a)(2)(iv){A) 50.73(a)(2)(x) o20.2203(a)(2)(iii)

D50.36(c)(2)

D50.73(a)(2)(v)(A)

D73.71(a)(4) 20.2203(a)(2)(iv) 50.46(a}(3)(ii}

50.73(a)(2)(v)(B) 73.71(a)(5)o20.2203(a)(2)(v) 50.73(a)(2)(i)(A)

D50.73(a)(2)(v)(C) 0OTHERo20.2203(a)(2)(vi) 50.73(a)(2)(i)(B) 050.73(a)(2)(v)(D) inAbstractbeloworForm366A12.LICENSEECONTACTFORTHISLERTElEPHONE NUMBER Manager(601)437-7326CAUSESYSTEM13.COMPLETEONELINEFOREACHCOMPONENT FAILUREDESCRIBED INTHISREPORTMANU-REPORMANU-COMPONENT FACTURERTOEPIXCAUSESYSTEMCTURERREPORTABLE TOEPIX14.SUPPLEMENTAL REPORTEXPECTEDYES(Ifyes,complete15.EXPECTEDSUBMISSION DATE)NOYEARN/AN/AN/AN/A15.EXPECTEDSUBMISSION DATEN/AN/AyA8S7TTi.e.,approximately 15single-spaced typewritten lines)ITAABSTRACT(LimittoonGulfanunexpected ReactorSCRAMfrom1000/0thermalpowerduetohighreactorpressuredetectedbytheReactorProtection System.Operations staffimmediately enteredtheappropriate off-normal eventprocedures.

ReactorCoreIsolation Cooling(RCIC)initiated andinjectedbrieflyduringthetransient.

TheRCICinitiation signalwasvalid,butnotrequiredtomaintainthereactorvesselwaterlevel.ReactorlevelswereverifiedandRCICwassubsequently secured.Allothersystemsoperatedasexpected.

Reactorpressurewascontrolled bydischarging steamtothemaincondenser viathemainturbinebypassvalves.Reactorwaterlevelwascontrolled usingthecondensate andfeedwater systemsviathestartuplevelcontrolvalve.Nosafetyreliefvalvesactuated.

ThecauseoftheSCRAMwasahumanperformance-induced errorduetoinadequate troubleshooting activities ontheTurbineAwasnotrecognized norcorrected, therebyresulting inafalsehighturbinestresstemperature signal.Uponrestoration oftheTSE,theincorrect signalforcedturbinecontrolvalvesinthecloseddirection andresultedinahighreactorpressuretransient.

Procedures andworkordersarebeingrevisedtopreventrecurrence ofthisevent.Therewerenoadverseeffectstothehealthandsafetyofthepublic.NRCFORM366(10-2010) 3.PAGE20F42.DOCKETLICENSEEEVENTREPORT(LER)u.s.NUCLEARREGULATORY COMMISSION CONTINUATION SHEET1.FACILITYNAMENRCFORM366ANARRATIVE 6.LERNUMBER1---------------1----------;1----

A.REPORTABLE OCCURRENCE ThisLicenseeEventReport(LER)isbeingsubmitted pursuanttoTitle10CodeofFederalRegulations (10CFR)50.73(a)(2)(iv)(A) foranautomatic actuation oftheReactorProtection System(EIIS:JC)

(RPS)andunplanned initiation oftheReactorCoreIsolation Cooling(EIIS:BN)

(RCIC)system.TheU.S.NuclearRegulatory Commission (NRC)Headquarters OPerations CenterwasnotifiedbyphoneonJuly30,2013,within4hoursoftheeventpursuantto10CFR50.72(b)(2)(iv)(B) fortheRPSactuation andwithin8hoursoftheeventpursuantto10CFR50.72(b)(3)(iv)(A) forinitiation ofRCICduringtheinitialtransient B.INITIALCONDITIONS AtthetimeoftheeventthereactorwasinMode1withreactorpowerat100percentthermalpower.FailureoftheTurbineStressEvaluator (EIIS:23)

(TSE)1N30N011BTemperature Transmitter (EIIS:TI) wasanunknowncondition priortotheSCRAM.C.DESCRIPTION OFOCCURRENCE At14:32CentralDaylightTimeonJuly30,201GrandGulfNuclearStation(GGNS)ovr...orlon'....OI"lanunexpected ReactorSCRAMduetoahighreactortransient TheSCRAMoccurredshortlyaftertheTSEinfluence wasturnedonfollowing maintenance tocleartheuTSESTUCabFailure"alarm.Atthetime,theplantwasoperating at100percentthermalpower.Operations staffimmediately enteredtheEmergency Procedure (EP)forReactorSCRAM,theReactorSCRAMOff-Normal EventProcedure (ONEP),andtheTurbineTripONEP.RCICsysteminitiated andinjectedduringthetransient duetoamomentary dropinwaterlevelthatwasseenontwooutoffourchannels.

RCICinitiation wasvalid,butnotrequiredtomaintainreactorwaterlevelasreactorfeedwater (EIIS:SJ) wasinserviceandoperating properly.

ReactorlevelwasverifiedandRCICwassubsequently secured.Allothersystemsoperatedasexpected.

was&eamviathemainturbinebypassvalves(EIIS:PCV).

Reactorwaterlevelwascontrolled usingthecondensate (EllS:SO)andfeedwater systemsviathestartuplevelcontrolvalve(EIIS:LCV).

Allcontrolrods(EIIS:ROD) insertedasdesigned.

Therewerenoactuations ofsafetyreliefvalves(EIIS:SRV) duringthisevent.ThehighestnotedpressurewasapprOXimately 1gauge(psig)lowestwaterlevelwas-40inchesonnarrowrangeindication channels.

NRCFORM366ALICENSEEEVENTREPORT(LER)u.s.NUCLEARREGULATORY COMMISSION CONTINUATION SHEET1.FACILITYNAME2.DOCKET6.LERNUMBER3.PAGEGrandGulfNuclearStation,Unit1NARRATIVE D.CAUSE05000416t---Y_EA_R

__

-;2013-003--0030F4ThecauseoftheSCRAMwasahumanperformance-induced errorduetoinadequate troubleshooting activities ontheTurbineStressEvaluator (TSE).Inresponsetoa"TSESTUCabFailure"alarm,GrandGulfmaintenance staffassumedthatthealphachanneltransmitter (1N30N011A) wasthecause.Maintenance staffwerepre-conditioned thisassumption basedonrecentTSEmaintenance whichrevealedthatthealphachanneltransmitter wasdegradedbutfunctional.

Thatassumption wasnotvalidated throughpropertroubleshooting atthetimeofdiscovery.

Afailuremodeanalysisperformed subsequent tothiseventidentified thatthebravochanneltransmitter (1N30N011B)wasthetruefailedcomponent.

Consequently, maintenance staffrestoredtheTSEwithoutthefailurebeingrepaired.

Uponrestoration, theTSEdetecteda100%mismatchbetweenthereference temperature signalandtheactualsteady-state fullpowertemperature signal.Theturbinecontrolsystemresponded, asdesigned, bystrokingtheturbinecontrolvalvesinthecloseddirection.

Reactorpressureincreased totheRPSactuation setpoint.

Nosituational ortimepressures wereidentified thatcontributed totheevent.Thecauseoftheautomatic RCICinitiation wasreactorwaterleveldecreaseimmediately following theSCRAM.E.CORRECTIVE ACTIONSThefollowing corrective actiontopreventrecurrence wascompleted:

Revisedmodelworkorders50025957,

50025958, and50025959forPreventative Maintenances 11A,118,and12,respectively, toincluderestoration stepsfromtheARI.Thefollowing corrective actionstopreventrecurrence willbeperformed:

ReviseStandardOperating Instruction (SOl)04-1-01-N32-2, "TurbineGenerator Control"toincludeanewstepwithinstructions onhowtoturntheTSEonandoff;andrevisetheAnnunciator ResponseInstruction (ARI)torefertoSOl04-1-01-N32-2 forinstructions onturningtheTSEonandoff.Reviseprocedure 02-S-01-41 "OnLineRiskAssessment" toincludetheActivityEvaluation Checklist (attached toCA18)forLowandNormalRiskEmergentActivities.

Checklist shallincludeaPEERreviewbyoneofthefollowing:

Maintenance Manager,WorkWeekManagerorShiftManagerpriortothebeginning ofanyemergentactivity.

Includeprovisions toensure:theproperleveloftroubleshooting isperformed perMA-125"Troubleshooting ControlofMaintenance Activities, the01-S-17-42 "Trip NRCFORM366ALICENSEEEVENTREPORT(LER)u.s.NUCLEARREGULATORY COMMISSION CONTINUATION SHEETGrand1.FACILITYNAMENuclearStation,Unit12.DOCKET050006.LERNUMBERYEARISEQUENTIAL IREV"NUMBERNO"3--003--003.PAGE40F4NARRATIVE CriticalProgram"isimplemented, restoration stepsareidentified, andresuftsareapprovedbyWorkWeekManager.F.SAFETYASSESSMENT TheeventposednothreattopublichealthandsafetyastheRPSperformed asdesigned.

Allsafetysystemsresponded asdesigned.

TheSCRAMsignalwasfromreactorhighpressureonchannelsBandC.PlotsofMainTurbineControlValveandbypassvalvepositions indicatethattheMainTurbineControlValvesclosedasthebypassvalvesopenedtomaintainreactorpressureasdesigned.

Whenthebypassvalvesreachedfullopen,thecontrolvalveswerecontinuing toclose,whichcausedacorresponding increaseinreactorpressuretothereactorhighpressureSCRAMsetpoint.Asaresult,anautomatic SCRAMoccurredduetoaHighReactorPressureof1065psig.Allcontrolrodsinsertedasdesigned.

Therewereno,...1::1ofsafetyreliefvalvesduringthisevent.Thehighestobservedreactorpressureof1065psigisboundedbytheexistinganalyzedeventintheGGNSUpdatedFinalSafetyAnalysisReport,Section15.2.AtnoeventwereanyTechnical Specification SafetyLimits'"I.L-Iorchallenged.

TherewerenoEmergency CoreCoolingSystemactuations ormalfunctions.

Immediate actionsperformed bytheOperationsstaffwere adequateandappropriate inplacingandmaintaining thereactorinasafeshutdowncondition.

Nuclearsafetywasnotcompromised becausesafety-related equipment Performed theirsafetyfunctions.

Radiological safetywasnotaffected, astherewasnoradiological IIduringtheevent.Theresponseofthecrewdidnotchallenge established industrial safetyprotocols orrequirements.

Therewasnoimpacttothehealthandsafetyofthepublic,industrial safety,orradiological safetyasaresultofthisevent.G.ADDITIONAL INFORMATION Condition Report(CR)CR-GGN-2013-4969 documents theunplanned RCICinitiation.

The1N30N011Btransmitter ismodelnumber315fromABB.Withinthepast2years,therewerenosimilarevents(i.e.,SCRAMorRCICinitiation asaresultofinadequate troubleshooting).