ML17262B154

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LER 92-007-00:on 921224,turbine Runback Occurred & a EDG Started & Tied Into Safeguard Buses 14 & 18.Caused by Loss of Power to Safeguards.Restored Normal Power to Safeguards Buses 14 & 18.W/930125 Ltr
ML17262B154
Person / Time
Site: Ginna Constellation icon.png
Issue date: 01/25/1993
From: BACKUS W H, MECREDY R C
ROCHESTER GAS & ELECTRIC CORP.
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-92-007, LER-92-7, NUDOCS 9302030096
Download: ML17262B154 (24)


Text

ACCELERADDOCUMENTDISTBUTIONSYSTEMREGULATORYINFORMATIONDISTRIBUTIOSYSTEM(RIDS)ACCESSIONNBR:9302030096DOC.DATE:93/01/25NOTARIZED:NODOCKET¹FACIL:50-244RobertEmmetGinnaNuclearPlant,Unit1,RochesterG05000244AUTH.NAMEAUTHORAFFILIATIONBACKUSiW.H.RochesterGas&ElectricCorp.MECREDY,R.C.RochesterGas&ElectricCorp.RECIP.NAMERECIPIENTAFFILIATION

SUBJECT:

LER92-007-00:on921224,turbinerunbackoccurred&"A"EDGstarted&tiedintosafeguardbuses14&18.Causedbylossofpowertosafeguards.Restorednormalpowertosafeguardsbuses14&18.W/930125ltr.DZSTRZBUTZONCODE:ZE22TCOPZESRECEZVED:LTR(ENCL(SZZE:TITLE:50.73/50.9LicenseeEventReport(LER),IncidentRpt,etc.NOTES:LicenseExpdateinaccordancewith10CFR2,2.109(9/19/72).D'05000244AiRECIPIENTIDCODE/NAMEPD1-3LAJOHNSON,AINTERNAL:ACNWAEOD/DSP/TPABNRR/DET/EMEB7ENRR/DLPQ/LPEB10NRR/DREP/PRPB11NRR/DST/SICB8H3NRR/DST/SRXB8ERES/DSIR/EIBEXTERNAL'G&GBRYCEiJHNRCPDRNSICPOOREgW.COPIESLTTRENCL11112211111122111111221111RECIPIENTIDCODE/NAMEPD1-3PDAEOD/DOAAEOD/ROAB/DSPNRR/DLPQ/LHFB10NRR/DOEA/OEABNRR/DST/SELB8DRRT/SSB8D1REGFILE02RGN1FILE01LSTLOBBYWARDNSICMURPHY,G.ANUDOCSFULLTXTCOPIESLTTRENCQ-111122111111111111111111DD/vNs7(7$DNOTETOALL"RIDS"RECIPIENTS:PLEASEHELPUSTOREDUCEWASTE(CONTACTTHEDOCUMENTCONTROLDESK,ROOMPI-37(EXT.504-2065)TOELIMINATEYOURNAMEFROMDISTRIBUTIONLISTSFORDOCUMENTSYOUDON'TNEED!DFULLTEXTCONVERSIONREQUIREDTOTALNUMBEROFCOPIESREQUIRED:LTTR29ENCL29

VJhf/I'iiROCHESTERGASANDELECTRICCORPORATION~89EASTAVENUE,ROCHESTER,N.Y.N$b5~~I~4/'lOtCj5Ts'ltI14649-00017CLCPnOhf,'+cAcooE715546.2700January25,1993U.S.NuclearRegulatoryCommissionDocumentControlDeskWashington,DC20555

Subject:

LER92-007,LossofOffsitePowerCircuit751,~DueToWindStormInducedDebris,CausesAutomaticActuationofAnESFandRPSSystem(i.e.EmergencyDieselGeneratorOperationandTurbineRunback)R.E.GinnaNuclearPowerPlantDocketNo.50-244Inaccordancewith10CFR50.73,LicenseeEventReportSystem,item(a)(2)(iv),whichrequiresareportof,"anyeventor-conditionthatresultedinmanualorautomaticactuationofanyEngineered.SafetyFeature(ESF),includingtheReactorProtectionSystem(RPS)",theattachedLicenseeEventReportLER92-007isherebysubmitted.Thiseventhasinnowayaffectedthepublic'shealthandsafety.Verytrulyyours,RobertC.MecrexcoU.S.NuclearRegulatoryCommissionRegionI475AllendaleRoadKingof-Prussia,PA19406GinnaUSNRCSeniorResidentInspector9302030096.930i25PDRADOCK05000244PDR~()P

NRCFORM366(64)9)LICENSEEEVENTREPORTILER)U.S.NUCLEARREGULATORYCOMMISSIONAPPROVED0MBNO.31504104EXPIRES:4/30/92ESTIMATEDBURDENPERRESPONSETOCOMPI.YWTHTHISINFORMATIONCOLLECTIONREQUEST:50.0HRS.FORWARDCOMMENTSREGARDINGBURDENESTIMATETOTHERECORDSANDREPORTSMANAGEMENTBRANCH(Pyr30),V.S.NUCLEARREGULATORYCOMMISSION.WASHINGTON.DC20555,ANDTOTHEPAPERWORKREDUCTIONPROJECT(31500104),OFFICEOFMANAGEMENTANDBUDGET,WASHINGTON.DC20503.FACILITYNAME(11R.E.GinnaNuclearPowerPlantDOCKETNVMBER(2)PAE30500024410F10LossofOffsitePowerCircuit751,DueToHindStormI'nducedDebris,Causes'AutomaticEVENTDATE(5)LERNUMBER(6)REPORTDATE(7)OTHERFACILITIESINVOLVED(6)MONTHDAYYEARYEAR~SEQUENTIALNSiNUMBERMO~ŽREVtSIONDAYYEARFACILITYNAMESDOCKETNUMBERISI0500012'40705000OPERATING'MODE(9)POWERLEVEL(10)THISREPORTISSUBMITTEDPURSUANTT50,73(~I(2)(le)60,73(~)(2)(e)60,73(s)(2)(r9)60.73(~)(2)(eII0(A)50,73(s)(2)(yiii)(6)50.'73(~)(2)(s).20.405(cl60.36(c)(1)60.36(c)(2)60.73(~I(2)(i)60.73(~l(2)(iil50.73(el(2)(iii)20.402(b)20406N)(1)IB20.405(sl(1)(6)20.405(s)((l(iiil20.405(s)(I)(IY)20.406(~l(I)(s)LICENSEECONTACTFORTHISLER(12)0THEREQUIREMENTSOF10CFR('ItIChrchonrormoreofthrfollowinPl(11'3.7((b)73.71(c)OTHERISprcifyinAbstractbelowendInFeet,HRCForm3BSAINAMEWesleyH.BackusTechnicalAssistanttotheOperationsManagerAREACODETELEPHONENUMBER315524-444COMPLETEONELINEFOREACHCOMPONENTFAILUREOESCRIBEOINTHISREPORT(13)CAUSESYSTEM'COMPONENTMANUFAC.TVRERREPORTABLETONPRDS54ISY@CAUSESYSTEMCOMPONENTMANUFACTUREREPORTABLETONPRDSXEACONX99SUPPLEMENTALREPORTEXPECTED(141YESIIIyet.complrtrEXPECTEDSUBAIISSIOHDATEINOABsTRAcTI(imlttof400spree5I.r.,epproelmrtr(yflftrrntlnplrspreetyprwriNrnlinni(16)EXPECTEDSUBMISSIONDATE'151MONTHDAYYEAROnDecember24,1992,at0435EST,withthereactoratapproxi-mately984-steadystatefullpower,aturbinerunbackoccurredandthe"A"EmergencyDieselGeneratorstartedandtiedintosafeguardbuses14and18.TheControlRoomoperatorsperformedtheappropriateactionsofAP-TURB.2(AutomaticTurbineRunback)andverifiedthatthe"A"EmergencyDieselGenerator,wasoperatingproperlyandthatsafeguardsbuses14and18were'nergized..Theplantwassub-sequentlystabilizedatapproximately774fullpower.Thecauseoftheeventwasthelossofpowertosafeguardsbuses14and18duetolossofoffsitepower34.'5KVCircuit751.TheunderlyingcauseforthelossofCircuit751wasdeterminedtobewindstorminduceddebrisinterceptingtheshieldwireandphaseconductorcausing.afault.(ThiseventisNUREG-1022(C)CauseCode).Correctiveactionwastorestorenormalpowertosafeguards-buses14and18fromoffsitepowersource34.5KVCircuit767andtostopthe"A"EmergencyDieselGeneratorandrealign-itforautostandby.NRCForm366(64)9)

NRCFORM368A(689)U.S.NUCLEARREGULATORYCOMMISSIONLICENSEEEVENTREPORT(LER)TEXTCONTINUATIONAPPROVEDOMBNO.31500104EXPIRES:4/30/92ESTIMATED8)/ADENPERRESPONSETOCOMPLYWTHTHISINFORMATIONCOLLECTIONREQUEST:500HRS.FORWARDCOMMENTSREGARDINGBURDENESTIMATETOTHERECORDSANDREPORTSMANAGEMENTBRANCHIP430),U.S.NUCLEARREGULATORYCOMMISSION,WASHINGTON,DC20555,ANDTO1NEPAPERWORKREDUCTIONPROJECT(31500104),OFFICEOFMANAGEMENTANDBUDGET,WASHINGTON,DC20503.FACILITYNAME(1)DOCKETNUMBER(2)YEARLERNUMBER(6)SEQUENTIALriceNUM44g~REVISIONNVMSE4PAGE(3)R.E.(rinnaNuclearPowerPlantTEXT/ffmorog>>co/4rtufrorf,u>>I/Rrur'>>fHRCForm35649/()2)0500024492-0070002o"10PRE-EVENTPLANTCONDITONSTheplantwasatapproximately98%steadystatepowerwithnomajoroperationalactivitiesinprogress.Theoffsitepowerconfigurationtotheplantwasasfollows:oOffsitepower34.5KVCircuit751wasfeedingthe"ALItrainsafeguardsbuses14and18through12A34.5KV/4160Vtransformerandthroughthesafeguardsbuses4160V/480Vtransformers.oOffsitepower34.5KVCircuit767wasfeedingthe"B"trainsafeguardsbuses16and17through12B34.5KV/4160Vtransformerandthroughthesafeguardsbuses4160V/480Vtransformers.-Theweatherconditionsintheareawerehighwinds,blowingsnow,andsubfreezingtemperatures.DESCRIPTIONOPEVENTA.DATESANDAPPROXIMATETIMESOPMAZOROCCURRENCES0December24,1992,0435EST:Eventdateandtime0December24,1992,0435EST:Discoverydateandtime0December24,1992,0435EST:ControlRoomoperatorsverifythe"A"'mergencyDieselGenerator(D/G)Operationandsafeguardsbuses14and18energized.December24,1992,0436EST:ControlRoomoperatorsperformtheappropriateactionsofabnormalprocedureAP-TURB.2(AutomaticTurbineRunback)andstabilizetheplant.0December24,1992,0501EST:Safeguardbuses14and18resuppliedfromoffsitepower34.5KVCircuit767.NRCForm368A(689)

NACFORM366A(669)U.S.NUCLEARREGULATORYCOMMISSIONLICENSEEEVENTREPORT(LER)TEXTCONTINUATIONAPPROVEDOMBNO.3150410EEXPIAES:6/30/92ESTIMATEDBURDENPEARESPONSETOCOMPLYWTHTHISINFOAMATIONCOLLECTIONREQUEST:50.0HRS.FORWARDCOMMENTSREGARDINGBURDENESTIMATETOTHERECORDSANDREPORTSMANAGEMENTBRANCH(PJ)30).U.S.NUCLEAR,REGULATORYCOMMISSION.WASHINGTON,OC20555,ANDTO1'HEPAPERWORKREDUCTIONPROJECT(31500104).OFFICEOFMANAGEMENTANDBUDGET,WASHINGTON.DC20503.FACILITYNAME(1)DOCKETNUMBER(2)YEARLERNUMBER(6)">SEOVENTIALNk'~INVMSERREREVISIONNVMERPAGE(3)R.E.GonnaNuclearPDT9erPlantTEXT///IIKVSSg>>Ct/SPNJV/RR/uW~NRCFee@36SAB/(17)050'0024492007-0003QF10o*December24,1992,0510EST:The<<A<<EmergencyD/Gwasstoppedandrealignedforautostandby.oDecember28,1992,0920EST:Offsitepower34.5KVCircuit751declaredoperable.B.EVENT:OnDecember24,1992,at0435EST,withthereactoratapproximately984steadystatefullpower,theControlRoomreceivednumerousannunciatoralarms.TheControlRoomoperatorsimmediatelydeterminedthatthefollowingeventshadoccurred:oSafeguardsbuses14and18hadlosttheirnormalpowersupply.E00Aturbinerunbackofapproximately204fullpowerhadoccurred.The<<A<<EmergencyD/Ghadstartedandwastiedtosafeguardsbuses14,and18.TheControlRoomoperatorsimmediatelyperformedtheappropriateactionsofAP-TURB.2(AutomaticTurbineRunback),transitionedtoAP-ELEC.1(Lossof12AAnd/Or12BTransformer)andverifiedthatthe<<A<<EmergencyD/Gwasoperatingproperlyandthatsafe-guardsbuses14and18wereenergized.Theplantwassubsequentlystabilizedatapproximately774fullpower.TheControlRoomoperatorsobservedthat4160Vbus12Aandoffsitepower34.5KVCircuit751displayedzero(0)voltage.TheControlRoomoperatorsperformedtheappropriateactionsofAP-,ELEC.landcontactedPowerControl.ThePowerControlDispatcherinformedthemthatoffsitepower34.5KVCircuit751hadtrippedat,substation204.~NRCFoe>366A(669)

NRCFORM366A(6J)9)tU.S.NUCLEARREGULATORYCOMMISSIONLICENSEEEVENTREPORTILER)TEXTCONTINUATIONAPPROVEDOMBNO.3(500104EXPIRES:O/30/92ESTIMATEDBURDENPERRESPONSETOCOMPLYWTHTHISINFORMATIONCOLLECTIONREQUEST:500HRS.FORWARDCOMMENTSREGARDINGBUADENESTIMATETOTHERECORDSANDREPORTSMANAGEMENTBRANCH(P430).U.S.NUCLEARREGULATORYCOMMISSION,WASHINGTON,DC20555,ANDTOTHEPAPERWORKREDUCTIONPROJECT(31500104).OFFICEOFMANAGEMENTANDBUDGET,WASHINGTON,0020503.FACILITYNAME(1)DOCKETNUMBER(2)YEARLERNUMBER(6):$N:SEQUENTIALNgi'EVISIONNUMER44NUMERPAGEIS)R.E.GinnaNuclearPowerPlantTEXT///marer/IOOO/Or/O/ver/IIOO///OrrO/HRCFOrrrr36//rEB/I)7)050002gg9007000OFSubsequently,at0452EST,theControlRoomoperators,usingEquipmentRestorationprocedureER-ELEC.1(RestorationofOffsitePower)energized4160VBus12Afromoffsitepower34.5KVCircuit.767.At0501ESTsafeguardbuses14and18wereresuppliedbyoffsitepower.At0510EST,December24,1992,the"A"EmergencyD/Gwasstoppedandrealignedforautostandby.At0920EST,December28,1992,afteroffsitepower34.5KVCircuit751hadbeenclearedforuse,normaloffsitepowerfromCircuit751wasmadeavailabletotheplant.Thecurrentoperatingalignmentutilizing34.5KVCircuit767isbeingmaintainedtosupplythe'safeguardstrains.Offsitepower34.5KVCircuit751wasmaintainedastheplant'sbackupsupplyofoffsitepower.CINOPERABLESTRUCTURESPCOMPONENTS,ORSYSTEMSTHATCONTRIBUTEDTOTHEEVENT:D.None.OTEGPRSYSTEMSORSECONDARYFUNCTIONSAFFECTED:None.E.METHODOFDISCOVERY:TheeventwasimmediatelyapparentduetoalarmsandindicationsintheControlRoom.NAGForm366A(649)

'

NRCFOAM366A(64)9)UA.NUCLEARREGULATORYCOMMISSIONLICENSEEEVENTREPORTILER)TEXTCONTINUATIONAPPROVEDOMBNO.31500104EXPIRES:4/30/92ESTIMATEDBURDENPERRESPONSETOCOMPLYWTHTHISINFORMATIONCOLLECTIONREQUEST:500HRS.FORWARDCOMMENTSREGARDINGBURDENESTIMATETOTHERECORDSANDREPORTSMANAGEMENTBRANCH(P.530),U.S,NUCLEARREGULATORYCOMMISSION,WASHINGTON,DC20555,ANDTOTHEPAPERWORKREDUCTIONPROJECT(3(500(04),OFFICEOFMANAGEMENTANDBUDGET,WASHINGTON,DC20503,FACILITYNAMEn)DOCKETNUMBER(2)YEARLFRNUMBER(6)@RSEQUENTIALj~JREVISIONNUMER..ANUMERPAGEIS)R.E.GonnaNuclearPowerPlantTEXT///mare4/raceEttertu/red,u>>add/r/arre/NRCFarm36649/((7)osooo24492007-0005OF10OPERATORACTION:Followingtheturbinerunback,buses14and18under-voltage,andthe"A"EmergencyD/Gautomaticstart,theControlRoomoperatorsimmediatelyperformedtheappropriateactionsofAP-TURB.2(AutomaticTurbineRunback)andverifiedthatthe"A"EmergencyD/Gwasoperatingproperlyandthatsafeguardsbuses14and18.wereenergized.Subsequently,theControlRoomoperatorsrestorednormalpowertobus14and18andstoppedandrealignedthe"A"EmergencyD/GforAutostandby.SAFETYSYSTEMRESPONSES:The"A"EmergencyD/Gautomaticallystarted,displayedpropervoltageandfrequencyandclosedintosafeguardsbuses14and18tosupplyemergencypower.III.CAUSEOFEVENTA.IMMEDIATECAUSE:TheautomaticturbinerunbackwascausedbyadroppedrodsignalfromtheNuclearInstrumentSystem(NIS)powerrangeN-42and/orfromtheMicroprocessorRodPositionIndication(MRPI)System.1Theautomaticactuationofthe"A"EmergencyD/Gwasduetoundervoltageonsafeguardsbuses14and18.NRCFarm366A(64)9) 1 NRCFORM366A(689)US.NUCI.EARAEGULATOAYCOMMISSIONLICENSEEEVENTREPORT(LER)TEXTCONTINUATIONAPPROVEDOMBNO.31504106EXPIRES:4/30/92ESTIMATEDBURDENPERRESPONSETOCOMPLYWTHTHISINFORMATIONCOLLECTIONREQUEST:50.0HRS.FORWARDCOMMENTSREGARDINGBURDENESTIMATETOTHERECORDSANDREPOATSMANAGEMENTBRANCH(F430),U.S.NUCLEARREGULATORYCOMMISSION,WASHINGTON,DC20555,ANDTO1HEPAPERWORKREDUCTIONPROJECT(31500104),OFFICEOFMANAGEMENTANDBUDGET,WASHINGTON,DC20503.FACILITYNAME(1)DOCKETNUMBER(21YEAR'LERNUMBER(6)SEQVENTIALHVMllER'?49:REVISIONNVMSEAPAGE(3)R.E.GonnaNuclearP016erPlantTEXT//!nxveHM>>ls/Poult,u>>sddhiondHRCAnn366AB/()7)050002gg920070006OF10B.INTERMEDIATECAUSES:ThedroppedRodsignalfromNISpowerrangeN-.42wasduetothemomentarylossofthe"B"instrumentbuswhichsuppliedpowertoN-42.Thelossofthe'B!'nstrumentbuswasdueto.themomentarylossofMCC-1Cwhichsuppliedpowertotheconstantvoltagetrans-formerforthe"B"instrumentbus..ThedroppedrodsignalfromtheMRPISystemwasduetothemomentarylossofMCC-1KwhichsuppliedpowertotheMRPISystem.ThelossofMCC-1KwasduetothemomentarylossofMCC-1Cwhich.suppliedpowertoMCC-1K.ThelossofMCC-1Cwasduetothemomentarylossofpowertosafeguardsbus14.Thelossofpowertosafeguardsbus14wasduetothelossofoffsitepower34.5KVCircuit751.Theundervoltageonsafeguardsbuses14and18wasduetothelossofoffsitepower34.5KVCircuit751.C.ROOTCAUSE:OnJanuary15,199334.5KVCircuit751waspatrolledusingbuckettrucks.AtpoleT-424onLake.Roadaburnedphaseconductorwasfound.Basedontheabovetheunderlyingcauseofthelossofoffsitepower34.5KVCircuit751wasdeterminedtobewindstorminduceddebrisinterceptingtheshieldwireandphaseconductorcausingafault.(Windgustsofupto33.5mph)NRCForm366A(669)

NRCFORM366A(64)9)U.S.NUCLEARREGULATORYCOMMISSIONLICENSEE.EVENTREPORT(LER)TEXTCONTINUATIONAPPROVEDOMBNO.31500104EXPIRES:4/30)92ESTIMATEDBURDENPERRESPONSETOCOMPLYWTHTHISINFORMATIONCOLLECTIONREQUEST:505)HRS.FORWARDCOMMENTSREGARDINGBURDENESTIMATETOTHERECORDSANDREPORTSMANAGEMENTBRANCH(PS30),U.S.NUCLEARREGULATORYCOMMISSION.WASHINGTON,OC20555,ANDTO1HEPAPERWORKREDUCTIONPROJECT(31504104),OFFICEOFMANAGEMENTANDBUDGET,WASHINGTON.DC20503.FACILITYNAME(IIDOCKETNUMBER(2)YEARLERNUMBER(6)SEQUENTIAI.NUMSERREVISIONNUMERPAGE(3)IR.E.'GinnaNuclearPowerPlantTEXTillIROIP<<coolotoquiod,uoooddldonolHRCFoun36SASI(12),0500024490070007"10IV.ANALYSISOFWHFNTTheeventisreportableinaccordancewith10CFR50.73,LicenseeEventReportSystem,item(a)(2)(iv),whichrequiresreportingof,"anyeventorcondition'hatresulted'inmanualorautomaticactuationofanyEngineeredSafetyFeature(ESF)includingtheReactorProtectionSystem(RPS)",inthattheautomaticturbinerunbackwasanautomaticactuationoftheRPSandthestartingofthe""A"EmergencyD/GwasanautomaticactuationofanESFsystem.Anassessmentwasperformedconsideringboththesafetyconsequencesandimplicationsofthiseventwiththefollowingresultsandconclusions:oAllreactorcontrolandprotectionsystemsperformedasdesignedtthuslimitingtheoveralleffectsoftheturbinerunbacktransient.oThe"A"EmergencyD/Goperatedasdesignedbystartingandsupplyingemergencypowertosafeguardsbuses14and18.oOffsitepower34.5KVCircuit767wasstillinoperationsupplyingpowertothe"B"trainsafeguardsbusesandsubsequentlywaslineduptoalso.supplypowertothe"A"trainsafeguardsbusesaspermittedbyplanttechnicalspecifications.Basedontheabove,itcanbeconcludedthatthepublic(shealthandsafetywasassuredatalltimes.'INRCForm366A(64)9)

NRCFORM366A'(64)9)UA.NUCLEARREGULATORYCOMMISSIONLICENSEEEVENTREPORT(LER)TEXTCONTINUATION~APPROVEDOMBNO.31504))04EXPIRES:4/30/92ESTIMATEDBURDENPERRESPONSETOCOMPLYWTHTHISINFORMATIONCOLLECTIONREOUESTI50.0HRS.FORWARDCOMMENTSREGARDINGBURDENESTIMATETOTHERECORDSANDREPORTSMANAGEMENTBRANCHIP4)30),U.S.NUCLEARREGULATORYCOMMISSION.WASHINGTON.DC20555,ANDTO1HEPAPERWORKREDUCTIONPROJECT(3)504))04).OFFICEOFMANAGEMENTANDBUDGET,WASHINGTON,DC20503.FACILITYNAMEulDOCKETNUMBER12)YEARLERNUMBERIS)SEOUENTIALNUMSERREVISIONNUMER~PAGEIS)R.E.GinnaNuclearPower.PlantTEXT/I/moreEoecel)reovter/,v>>er/drT/one/HRCForm3ÃA'4)117)06000244920070008oF10V.CORREIVEACTIONA.ACTIONTAKENTOM%URNAFFECTEDSXSTEMSTOPRE-EV19lTNORMALSTATUS:Aftertheplanthadbeenstabilized,safeguardsbuses14and18normalpowersupplieswererestoredviaoffsitepower34.5KVCircuit767andthe"A"EmergencyD/Gwasstoppedandalignedforautostandby.Subsequentlyanextensivetroubleshootingeffortwasundertakentodeterminetherootcauseofoffsitepower34.5KVCircuit751trippingoutatsubstation204.Thistroubleshootingeffortincludedthefollowing:oPerformingavisualandinstrumentsurveyalongtheentirelengthofoffsitepower34.5KVCircuit751betweentheplantandsubstation204.toascertainiftherewereanydamagedinsulators,treelimbs,orotherdebrisonlines,orevidenceofanythingthathadpossiblyfallenacrossthelineandburnedfree.Noabnormalconditionsweredetected.0Inspectingsubstation204-foranyabnormalconditions'i.e.breakers,wires,monitoringequipment,etc.).Noabnormalconditionsweredetected,exceptadistancemonitordidindicateaproblemhadoccurredata'certaindistance-fromStation204.Thisarea-wascheckedoutwithnoabnormalconditionsdetected.NRCFonII366A)669)

NRCFORM355A(SJ)B)ILS.NUCLEARREGULATORYCOMMISSIONLICENSEEEVENTREPORTILER)TEXTCONTINUATIONAPPRDYED0MBNo.3150010eEXPIRES:e/30/02ESTIMATEDBURDENPERRESPONSETOCOMPLYWTHTHISINFORMATIONCOLLECTIONREOUESTI508>HRS.FORWARDCOMMENTSREGARDINGBURDENESTIMATETOTHERECORDSANDREPORTSMANAGEMENTBRANCH(P430),U.S.NUCLEARREGULATORYCOMMISSION,WASHINGTON,DC20555,ANDTO1HEPAPERWORKREDUCTIONPROJECT(31504(04).OFFICEOFMANAGEMENTANDBUDGET,WASHINGTON,OC20503.FACILITYNAME(1)DOCKETNUMBER(2)LERNUMBERIS)PAGE(3)R.E.GlnnaNuclearPowerPlantTEXT///mmerpoco/sroeIJPed,ooo~HRCFomI3SSA'e/(17)YEAR'osooo24492seaveNTIAL;.y)NIJMseII007REVLsIONNVMSER009OF.l0oPlacingahighpotentialtestonCircuit751*(i.e.approximately70KV)toidentifypossibleintermittentabnormalconditions.Oneabnormalconditionwasdiscoveredonwireconnectinglinks'oftwophasesoftheCircuit.Theselinkswerefoundtohavepinholesinthejacketcovering.RochesterGasandElectricCorporation(RG&E)TransmissionandDistributionDepartmentbelievesthesepinholeswerecausedbythehighpotentialtestplacedontheline.Nocorrelationbetweenthepinholesandtheoriginalinitiatingeventcouldbedrawn.Thelinksweresubsequentlyrepairedandretestedsatisfactorily.Nootherabnormalconditionsweredetected.oOnDecember28,1992at0920ESToffsitepower34.5KVCircuit751wasdeclaredoperableandclearedforuse.ACTZONTAKENORPLANNEDTO,PREVENTRECUMUDtCEAstheunderlyingcausewasdeterminedtobewindstorminduceddebrisinterceptingtheshieldwireandphaseconductorcausingafault,thefollowingcorrectiveactionwastakentopreventrecurrence:0Treetrimmingeffortsfor34.5KVCircuit751werereviewedandadditionaltrimmingwascompletedasofJanuary11,1993atpoleT-424onLakeRoadandT-25AandT-26AonSlocumRoad.TheRG&ETransmissionandDistributionDepartmentwillcontinuetheirpracticeofAerialpatrolof34.5KVCircuit751twiceperyearutilizingthermalimagingandvisualassessmentofencroachmentsandgeneralline'ntegrity.Basedonthoseassessmentsappropriatemaintenanceactivitieswillbeperformed.NRCFomI355A(SJ)B)

NRCFORM366A(689)US.NUCLEARREGULATORYCOMMISSIONLICENSEEEVENTREPORT(LER)TEXTCONTINUATION'PPROVEDOMBNO.31600104EXPIRES:E/30/92ESTIMATEDBURDENPERRESPONSETOCOMPLYWTHTHISINFORMATIONCOLLFCTIONREOUEST:600HRS.FORWARDCOMMENTSREGARDINGBURDENESTIMATETOTHERECORDSANDREPORTSMANAGEMENTBRANCHIP430),U.S.NUCLEARREGULATORYCOMMISSION,WASHINGTON.DC20556,ANDTO1HEPAPERWORKREDUCTIONPROJECT(3150410>>),OFFICEOFMANAGEMENTANDBUDGET,WASHINGTON,DC20503.FACILITYNAME(1)DOCKETNUMBER(2)LERNUMBER(6)VEARI,>PISEQUENTIAL~5iREVISIONNUMSER'>ANUMBERPAGE(3)R.E.GonnaNuclearPowerPlantTEXT///moree/wc>>/en/Ir/rerLe>>a//I/Oo>>/HRC%%drIIISBSE3/(12)osooo24492007-010OF10ADDITIONALINFORMAT0A.FAILEDCOMPONENTS:B.Thewireconnectinglinksareofunknownoriginwith,nopartnumberormodelnumber.PREVIOUSLERsONSIMILAREVENTS:AsimilarLEReventhistoricalsearchwasconductedwiththefollowingresults:NodocumentationofsimilarLEReventswiththesamerootcauseatGinnaStationcouldbeidentified.'owever,LER91-002wasasimilareventwithadifferentrootcause.CSPECIALCOMMENTS:None.NRCFoIm366A(669) 1