ML17251A976

LER 88-001-00:on 880205,reactor Trip Occurred.Caused by Higher than Normal Count Rate on Source Range (SR) Nuclear Instrumentation Sys Due to Faulty Connectors at Detectors. SR Detectors replaced.W/880307 Ltr

ML17251A976
Person / Time
Site:	Ginna
Issue date:	03/07/1988
From:	BACKUS W H, SNOW B A ROCHESTER GAS & ELECTRIC CORP.
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
LER-88-001, LER-88-1, NUDOCS 8803140134
Download: ML17251A976 (9)

Text

ACCELERATEDDlRIBUTIONDEMONSTTIONSYSTEMC7REGULATORYINFORMATIONDISTRIBUTIONSYSTEM(RIDS)ACCESSIONNBR:8803140134DOC.DATE:88/03/07NOTARIZED:NODOCKETgFACIL:50-244RobertEmmetGinnaNuclearPlant,Unit1,RochesterG05000244AUTH.NAMEAUTHORAFFILIATIONBACKUS,W.H.RochesterGas&ElectricCorp.RECIP.NAMERECIPIENTAFFILIATIONW/8DISTRIBUTIONCODE:IE22DCOPIESRECEIVED:LTR4ENCL)SIZE:TITLE:50.73LicenseeEventReport(LER),IncientRpt,etc..D05000244S.NOTES:LicenseExpdateinaccordancewith10CFR2,2.109(9/19/72).

SUBJECT:

LER88-001-00:on880205,higherthannormalcountrateonsourcerangeNISduetofaultyconnectors.ltr.RECIPIENTIDCODE/NAMEPD1-3LASTAHLE,CINTERNAL:ACRSMICHELSONAEOD/DOAAEOD/DSP/ROABARM/DCTS/DABNRR/DEST/ADS7E4NRR/DEST/ESB8DNRR/DEST/MEB9H3NRR/DEST/PSB8D1NRR/DEST/SGB8DNRR/DLPQ/QAB10ANRR/DREP/RAB10ANRR/J)RISSIB9A1REGF02DEIBRGN1FILE01EXTERNAL:EG&GGROH,MHSTLOBBYWARDNRC-PDRNSICMAYS,GCOPIESLTTRENCL111111112211101111111111111111111155111111RECIPIENTIDCODE/NAMEPD1-3PDACRSMOELLERAEOD/DSP/NASAEOD/DSP/TPABDEDRONRR/DEST/CEB8H7NRR/DEST/ICSB7ANRR/DEST/MTB9H'RR/DEST/RSB8ENRR/DLPQ/HFB10DNRR/DOEA/EAB11ENRR/DREP/RPB10ANRR/PMAS/ILRB12RESTELFORD,JRES/DRPSDIRFORDBLDGHOY,ALPDRNSICHARRIS,JCOPIESLTTRENCL1122111111111.11111111122-111111111111i'SIATOTALNUMBEROFCOPIESREQUIRED:LTTR46ENCL45 HACfr>orSOS(9021LICENSEEEVENTREPORT{LER)Uh,NVCLKAllIllOVLATOIIYCOMMISSIONAPPROVEDOMSNO.1190OIO>tEXPIRES~0/Sl/SSfACILITYNAME(IlR>EGiaNuclearPower1DOCKETNVMSEII(1106000PA1OFTITLElclHigherThanNormalCountRateonSourceRangeNISDuetoFaultyConnectors,EVENTDATEISILERNVMS(SIRltORTDATEIOTHERFACILITIKSINVDLVKDIl)MONTHDAYYEARYKARIKOVINT>ALcScl?NUM91A>>VMSKAMONTHDAYYEARFACILITYNAMKSDOCKETNVMSER(5105000020600ODPKAATINOloOOKI~)~OrrKIILKVEL110)SÃ55~410.401(ol2O.COS(~)II)(01o.oosIoIllII1120.400(o)(1)(10)20.c004)(l)(>r)20.SOS4)ll)lr)20.409(rlSOW(~)IllSOMlaI(2)90.72(oI(2III)90,714IISII9)90.714)(2IIPS)LICKNSKKCONTACTFORTHISLERI'ISI90.724)(11(tr)90.7141(1(lrl90.724)(1)l>SI90.71(o)(2l(rt>I)IA)90.71(o)(1)lrtl)ISI90.711>I(1)4)THISI(KtOATISSVSMITTKDPURSUANTTO'THKAKOUIAEMENTSOf10CFIIf!(Corrioooo>moreott>>otot>o>>otl(ill72.71(~)72.71(4)OTHE(I/h>>CIIYIoAOotrrtoslo>>oo>tipTort,NhCfromJ>MA)NAMEWesleyH.BackusTechnicalAssistanttothAREACOPETELEPHONENUMSERCOMtLKTKONELINEfOAEACHCOMPONENTFAILUREDESCIIISKOINTHIS"REPORT'(12)CAVSESYSTEMCOMPONENTMANUFACTVREREtDRTASLETONPRDSg3'9':2CAUSESYSTEMCOMPONENTgci)%Egg.:c(N~4xgjE~S~<gjyocgk'ANUFACTUAEREPORTASLTONtADS~i-'paPi'-'mTS~4Y4SVttLKMKNTALAKPORTEXtECTEDIl~)YESlttyor.comp>>toEXP/CTTDSVFNISSIOIrDATE/NOASSTAACT(LlmtttO(COO>p>cor,Ko..opp>o>P>>otrlyIIIHoo>lottosP>totytr>rrtttooI>or>Ill~IEXPECTEDSV9MIS9IOHDATE114IMONTHDAYYEAROnFebruary5,1988at1857ESTwiththereactorsubcriticalduringaplannedshutdownfortheAnnualRefuelingandMaintenanceOutage,areactortripoccurredfromSourceRange(SR)HiFlux.Thetworeactortripbreakersopenedasrequiredandallshutdownandcontrolrodsinsertedasdesigned.ThereactortripwasduetotheSRinstrumentsindicatinghigherthannormalcountratewhenre-energizedduringthecontrolledshutdown.Therootcauseofthehigherthannormalcountratewascircuitnoisecausedbyfaultyconnectorsatthedetectors,possiblydamagedbypersonnelorobjectsenteringtheinstrumentportsoImmediatecorrectiveactionwastostabilizetheplant,rackoutandholdthereactortripbreakers,andboratetheReactorCoolantSystemtorefuelingshutdownconcentration.Subsequentactionwastochangeoutthetwosourcerangedetectors.Actionplannedtopreventrecurrenceistoinstallprotectivegratingsovertheinstrumentportsduringoutages.SP03iq0130SS0307PDRAOOCK05000244eopaa)ggNRCfr>m7OS(907)

NRCfonsESSA(SS5ILICENSEEEVENTREPORTILER)TEXTCONTINUATIONU.S,NUCLEARREOULATORYCOMMISSIONAPPROVEOOMSNO.315OWI04EXPIRES'ISIISffACILITYNAMEIIIOOCKETNUMSERIEILERNUMSERI~ICCQVCNTIALII'CVISXINNVMCCR"NVMCWR.E.GonnaNuclearPowerPlantTEXTTII'momcfcfcIctryakeCNPP~NIICJemISIEIASIllllosooo24488010002OF07PRE-EVENTPLANTCONDITIONSUnitshutdownwasinprogressperOperatingProcedure0-2.1(NormalShutdownToHotShutdown)fortheAnnualRefuelingandMaintenanceOutage.DESCRIPTIONOFEVENTA.EVENT:OnFebruary5,1988at1857ESTwiththereactorsubcriticalduringaplannedshutdown,areactortripoccurredfromSourceRange(SR)HiFluxwhentheSRNuclearInstrumentationSystem(NIS),uponre-energizingatthenormalsetpointof5x1011ampsontheIntermediateRanges(IR)NIS,indicatedhigherthannormalcountrate.TheControlRoomoperatorsperformedtheactions'fEmergencyOperatingProceduresE-0(ReactorTriporSafetyIn)ection),andES-O.l(ReactorTripResponse),andstabilizedtheplant.TheControlRoomoperators,perprocedureER-NIS.1(SRMalfunction),heldopenthereactortripbreakers,continuedborationtorefuelingshutdownandnotifiedtheInstrumentandControlDepartmenttoinvestigate.B.INOPERABLESTRUCTURESfCOMPONENTSPORSYSTEMSTHATCONTRIBUTEDTOTHEEVENT:NoneNRCCORMSCCAIS43l NIICSenwESSAI045ILICENSEEEVENTREPORT{LER)TEXTCONTINUATIONU.S.NUCLEAIIIIEOULATOIITCOMMISSIONAPPROVEOOMSNO.SISOWI04EX~IRE5SISIIS5SACILITYNAMEIIIOOCKETNUMSEIIITILERNUMSERlSI55QVSIITIALNUM5IIREVISIONMVMPACEISIR.E.GinnaNuclearPowerPlantTEXT(JI'ROW~NISSMISCM55SIMSSRSINIICAnnSSLSSl(ITI0500024488010003oF0C.DATESANDAPPROXIMATETIMESFORMAJOROCCURRENCES:oFebruary5,1988,1857EST:EventdateandtimeoFebruary5,1988,1857EST:Discoverydate'ndtimeoFebruary5,1988,1914EST:ReactortripbreakersrackedoutandheldoFebruary6,1988,0120EST:SourceRangeNISN-31andN-32declaredinoperableoFebruary6,1988,0221EST:ReactorCoolantSystemBoronConcentrationatrefuelingshutdownconcentration(2004ppm)o'ebruary7,1988,1147EST:SourceRangeNISN-32declaredoperableoFebruary8,1988,1118EST:SourceRangeNISN-31declaredoperableD.E.OTHERSYSTEMSORSECONDARYFUNCTIONSAFFECTED:NoneMETHODOFDISCOVERY:TheeventwasimmediatelyapparentduetoalarmsandindicationsintheControlRoom.NRCSOIIMSSSAIS4$I NRCPerm1EEA(04$lLICENSEEEVENTREPORT{LERITEXTCONTINUATIONU.E.NUCLEARREOULAEORYCOMMIEEIONAPPROVEOOMENO.1150&IIMER~IREEEI1IIESSACILIEYNAMEIIIOOCKEYNUMEER11ILERNUMEERI~I~~PSSEQUENTIALNUMINEllREVISIONNVMER~AOEI1IR.E.GinnaNuclearPowerPlantEEXEllSIRONSPASSEDPPPSESPNESSSSSMEbnatHIICAnn~'PlI171o5ooo24488-0010040F07F.OPERATORACTION:0AfterthereactortriptheControlRoomoperatorsperformedtheactionsofEmergencyOperatingProceduresE-O(ReactorTriporSafetyInjection),andES-0.1(ReactorTripResponse)andstabilizedtheplant.SubsequentlytheControlRoomoperatorsperformedtheactionsofequipmentrestorationprocedureER-NIS.1(SRMalfunction)andheldthereactortripbreakersrackedout,continuedRCSborationtorefuelingshutdownconcentrationandnotifiedtheInstrumentandControl(I&C)DepartmentoftheSRmalfunction.III.CAUSEOFVlENTA.IMMEDIATECAUSE:ThereactortripoccurredduetoSRNZSHiFlux(i.e.SRcountrategreaterthanorequalto10countspersecond(cps)).B.INTERMEDIATECAUSE:TheSRHiFluxreactortripwasreceivedbecausetheSRNISwasindicatinghigherthannormalcountratewhentheyre-energizedautomaticallyastheIRNISdecreasedbelow5x1011amps.C.ROOTCAUSE:TherootcauseofthehigherthannormalcountrateontheSRNZSwasduetonoisecausedbyfaultyconnectorsatthedetectors.Ztisbelievedthattheseconnectorscouldhavebeendamagedbypersonsorobjectsenteringtheinstrumentportholesduringworkinthereactorcavity.NRCSORM1EEAI043I II~NRCSebumSSSA10431LICENSEEEVENTREPORTILER)TEXTCONTINUATIONU.S.NUCLEARRSOULATORYCOMMISSIONASSROVSOOMbNO.SISOWI04SXSIRSSSISIISSSACILITYNAMS111LSRNUMSSRISI,IvrSloUSNTtALNUMfsRSVI%IONNUMTRR.E.GonnaNuclearPowerPlantVgaSITnsso~H~ooooAWonolH11CFonsJRSA'ol11710S0002448-001005oF07ANALYSISOFEVENTThiseventisreportableinaccordancewith10CFR50.73,LicenseeEventReportSystem,item(a)(2)(iv)whichrequiresreportingof,<<anyeventorconditionthatresultedinmanualorautomaticactuationofanyEngineeredSafetyFeature(ESF),includingtheReactorProtectionSystem(RPS),<<inthattheSourceRangeHiFluxreactortripwasanautomaticactuationoftheRPS.TheSourceRangeinstrumentationsystemalsohadaTechnicalSpecification(TS)operabilityactionstatementassociatedwithit.ThisactionstatementfromTStable3.5.1,actionstatement4states,"withthenumberofoperablechannelsonelessthantheminimumoperablechannelrequirement(i.e.2sourcerangeinstruments),suspendalloperationsinvolvingpositivereactivitychanges.Ifthechannelisnotrestoredtooperablestatuswithin48hours,openthereactortripbreakerswithinthenexthour."Theplantoperatorsrackedoutandheldthereactortripbreakerssoonafterthereactortripandonlynegativereactivitychangesweremadethereafter.Anassessmentwasperformedconsideringboththesafetyconsequencesandimplicationsofthiseventwiththefollowingresultsandconclusions:TherewerenooperationalorsafetyconsequencesattributedtotheSRHi,Fluxreactortripbecause:oThetworeactortripbreakersopenedasrequired.oAllwithdrawncontrolandshutdownrodsinsertedasdesigned.oTheunitwasalreadyshutdownwiththereactorsub-criticalsotherewerenopower,temperature,orpressuretransientsrelatedtothereactortrip.NRCSORMSOOA10431 A~'NRCFP////0FCA100'PLICENSEEEVENTREPORT(LER)TEXTCONTINUATIONU.S.NUCLEARRTOVLATORYCOMMITNONAPPROVEOOMSNO0150WI04fXPIRK$8/lI/SSFACILITYNAMC111OOCRKTNUMITRIllLTRNUMICRIIIYTAR'A,'%0UT/IT/ALNVMPTRA1V/T/0//NUM~RR.E.GinnaNuclearPowerPlantTSCl'X/RP/PRaeoP4terakeC~~HIICAn/I~'Pl111105000880010006oF07Implicationsoftheeventwerethelossofaccuratecore'neutronfluxmonitoringforshutdownconsiderations.Areviewoftheseimplicationswasmadewiththefollowingresults:oNucleardataaccumulated,followingthecontrolledshutdownindicatesthattheactualneutronfluenceattheSRdetectorlocationswaswellbelowthetripsetpointof10cps.oThefailureoftheSRNIS'swasintheconservativedirection(i.e.theindicatedcountratewashigherthantheactualcountrate).oWiththecontrolledshutdownnegativereactivitywasaddedcontinuouslyusingBoricAcidadditionasreactorpowerwasdecreased.ThisBoricAcidadditionwascontinuedafterthereactorwassubcriticalthusassuringmorethanadequatecoreshutdownmarginatalltimes.oAfterthereactortripthereactortripbreakerswererackedoutandheld,assuringnoinadvertentpositivereactivityinsertionduetocontrolrods.BasedontheaboveitcanbeconcludedthatcoreshutdownmarginwasmorethanadequateatalltimesduringtheSRNISmalfunctionassuringthepublic'shealthandsafety.VCORRECTIVEACTIONA.ACTIONTAKENTORETURNAFFECTEDSYSTEMSTOPRE-EVENTNORMALSTATUS:oSourceRangedetectorsforN-31andN-32SRchannelswerereplacedwithnewdetectors.WiththesenewdetectorstheSRchannelswerecali-bratedandtestedsatisfactorily.NIICI'ORM0FF*104ll NRCPermSSSAISSSILICENSEEEVENTREPORTILER)TEXTCONTINUATIONU.S.NUCLEARRSOULATORYCOMMISSIONAPPROYSOOMSNO.$150WI04SRPIRSSSISI/SSPACILITYNAMSIIIR.E.GonnaNuclearPowerPlantTSXTIPmore~NreerrOeCrrooeerAlorNPHRCAmrSHIA'olIITIOOCKSTNUMSSRl1)0500024488LSRNUMSSRlSISSOUCNTIALHUM%1-001P~OSYISrONrrUMSA-00PAOSISI7oF07oSubsequentinvestigationrevealedthattheN-31SRdetectorconnectorwasbrokenatthedetector.Thisconnectorwasreplacedandtestedsatis-factorily.oSubsequentinvestigationrevealedthattheN-32SRdetectorconnectorwasdirty.Thisconnectorwascleanedandtestedsatisfactorily.B.ACTIONTAKENORPLANNEDTOPREVENTRECURRENCE:oGinnaStationWorkRequestTroubleReportNo.88-1331wasinitiatedtodesign,manufactureandinstallheavygaugetubingorarmoredgratingovertheNISinstrumentportstoprotectagainstpeopleandtoolsfromfallingintotheinstrumentportsduringoutages.ADDITIONALINFORMATIONA.FAILEDCOMPONENTS:oThefaultycomponentswere:AmphenolConnectors,partnumber52975-1051.B~PREVIOUSLERsONSIMILAREVENTS:AsimilarLEReventhistoricalsearchwasconductedwiththefollowingresults:NodocumentationofsimilarLEReventsatGinnaStationcouldbeidentified.C.SPECIALCOMMENTS:TheindustrywasnotifiedofthiseventthroughNuclearNetworkonFebruary24,1988.HRCPORMSOSAI5SSI ROCMESTERGASANDELECTRICCORPORATION~89EASTAVENUE,ROCMESTER,N.Y.I4649Tfcl'~~Pal'oiAcoDE:~II562March7,1988U.S.NuclearRegulatoryCommissionDocumentControlDeskWashington,DC20555

Subject:

LER88-001,HigherThanNormalCountRateOnSourceRangeNISDueToFaultyConnectors,CausesReactorTripDuringSourceRangeRe-energization.R.E.GinnaNuclearPowerPlantDocketNo.50-244Inaccordancewith10CFR50.73,LicenseeEventReportSystem,item(a)(2)(iv)whichrequiresareportof,"anyeventorconditionthatresultedinmanualorautomaticactuationofanyEngineeredSafetyFeature(ESF),includingtheReactorProtectionSystem(RPS),"theattachedLicenseeEventReportLER88-001isherebysubmitted.Thiseventhasinnowayaffectedthepublic'shealthandsafety.BruceA.SnowSuperintendentofNuclearProductionxceU.S.NuclearRegulatoryCommissionRegionI475AllendaleRoadKingofPrussia,PA19406GinnaUSNRCResidentInspectorZ~lf