ML17263A563

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LER 94-005-00:on 940217,turbine Runback Occurred Due to Lost Offsite Power Circuit 751 Causing Low Voltage on Safeguard Busses 14 & 18.Circuit 751 Restored by Automatic Reclosure of Transformer breaker.W/940321 Ltr
ML17263A563
Person / Time
Site: Ginna Constellation icon.png
Issue date: 03/21/1994
From: MCCREDY R C, ST MARTIN J T
ROCHESTER GAS & ELECTRIC CORP.
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-94-005, LER-94-5, NUDOCS 9403290326
Download: ML17263A563 (12)


Text

ACCj"-'LBRA"I"BD DlSTRlBUTluN DEMON&"I'RA'i'los SYSl'UIvll,ttREGULATORY INFORMATION DISTRIBUTION SYSTEM(RIDS)ACCESSION NBR:9403290326 DOC.DATE:

94/03/21NOTARIZED:

NOFACIL:50-244 RobertEmmetGinnaNuclearPlant,Unit1,Rochester GAUTH.NAMEAUTHORAFFILIATION STMARTIN,J.T.

Rochester Gas&Electric'Corp.MCCREDY,R.C.

Rochester Gas&ElectricCorp.RECIP.NAME RECIPIENT AFFILIATION DOCKET05000244

SUBJECT:

LER94-005-00:on 940217,turbine runbackoccurredduetolostoffsitepowercircuit751causinglowvoltageonsafegaurd busses14&18.Circuit 751restoredbyautomatic reclosure oftransformer breaker.940321 ltr.DISTRIBUTION CODE:IE22TCOPIESRECEIVED:LTR ENCLSIZE:TITLE:50.73/50.9 LicenseeEventReport(LER),IncidentRpt,etc.DNOTES:License Expdateinaccordance with10CFR2,2.109(9/19/72).

05000244ADRECIPIENT IDCODE/NAME PD1-3PDINTERNAL:

AEOD/DOAAEOD/ROAB/DSP NRR/DE/EMEB NRR/DRCH/HHFB NRR/DRCH/HOLB NRR/DRSS/PRPB NRR/DSSA/SRXB RES/DSIR/EIB EXTERNALEG&GBRYCEgJ~HNRCPDRNSICPOORE,W.COPIESLTTRENCL111122111111221111221111RECIPIENT IDCODE/NAME JOHNSON,A AEOD/DSP/TPABNRR/DE/EELB NRR/DORS/OEAB NRR/DRCH/HICB NRR/DRIL/RPEB LSTLOBBYWARDNSICMURPHY,G.A NUDOCSFULLTXTCOPIESLTTRENCL111111111111111111111111DDS'OTETOALL"RIDS"RECIPIENTS:

PLEASEHELPUSTOREDUCEWARMCONTACTTHEDOCUMENTCONTROLDESK,ROOMPl-37(EXT.20079)TOELIMINATE YOURNAMEFROMDISTRIBUTION LISTSFORDOCUMENTS YOUDON'TNEED!DD'SFULLTEXTCONVERSION REQUIREDTOTALNUMBEROFCOPIESREQUIRED:

LTTR27ENCL27

'1ROCHESTER GASANDELECTRICCORPORATION e89EASTAVENUE,ROCHESTER N.Y.14649-0001 ROBERTCMECREDYVicePtetldent Cinnatcvctearpcodoction TEt.EPk<ONB aAEACOnE7te546-2700March21,1994U.S.NuclearRegulatory Commission DocumentControlDeskAttn:AllenR.JohnsonProjectDirectorate I-3Washington, D.C.20555

Subject:

LER94-005,LossofOffsitePowerCircuit751,DuetoLossofPowerto¹234.5KVBusatStation204,CausesAutomatic Actuation ofRPSSystem(TurbineRunback)R.E.GinnaNuclearPowerPlantDocketNo.50-244Inaccordance with10CFR50.73,LicenseeEventReportSystem,item(a)(2)(iv),whichrequiresareportof,"Anyeventorcondition thatresultedinamanualorautomatic actuation ofanyengineered safetyfeature(ESF),including thereactorprotection system(RPS)",theattachedLicenseeEventReportLER94-005isherebysubmitted.

Thiseventhasinnowayaffectedthepublic'shealthandsafety.Verytrulyyours,go(RobertC.Mecredyxc:U.S.NuclearRegulatory Commission RegionI475Allendale RoadKingofPrussia,PA19406GinnaSeniorResidentInspector 940329032b 940321PDRADOCKOS0002448PDR NRCFORH366(5-92)U.S.NUCLEARREGULATORY COMMISSION APPROVEDBYOMBNO.31500104EXPIRES5/31/95LICENSEEEVENTREPORT(LER)(Seereverseforrequirednumberofdigits/characters foreachblock)ESTIMATED BURDENPERRESPONSETOCOMPLY'WITHTHISINFORHATION COLLECTION REQUEST:50.0MRS.FORWARDCOMMENTSREGARDING BURDENESTIHATETOTHEIHFORHATION ANDRECORDSHANAGEHENT BRANCH(HNBB7714),U.S.NUCLEARREGULATORY COMHISSION, WASHINGTON, DC20555-0001, ANDTOTHEPAPERWORK REDUCTION PROJECT(3150-0104),

OFFICEOFHANAGEHENT ANDBUDGETWASHINGTON DC20503.FACILITYNAME(1)R.E.GinnaNuclearPowerPlantDOCKETNUMBER(2)05000244PAGE(3)10F9TITLE(4)LossofOffsitePowerCircuit751,DuetoLossofPowerto¹234'KVBusatStation204,CausesAutomatic Actuation ofRPSSystem(TurbineRunback)LERNUHBER(6)SEQUENTIAL NUHBER--005--EVENTDATE(5)REVISIONNUMBERYEARYEAR9494MONTHDAY0217OPERATING HODE(9)00N20.402(b)

THISREPORTISSUBMITTED PURSUANTREPORTDATE(7)OTHERFACILITIES INVOLVED(B)HONTH03DAY21FACILITYNAHEYEARFACILITYNAHEDOCKETNUMBERDOCKETNUHBERTOTHEREQUIREMENTS OF10CFR5:(Checkoneormore)(ll)20.405(c) 50.73(a)(2)(iv) 73.71(b)XPOWERLEVEL(10)09B20'05(a)(1)(t)20.405(a)(1)(ii) 20'05(a)(1)(iii) 20.405(a)(1)(iv) 20.405(a)(1)(v) 50.36(c)(1) 50.36(c)(2) 50.73(a)(2)(i) 50.73(a)(2)(ii) 50.73(a)(2)(iii) 50'3(a)(2)(v) 50.73(a)(2)(vii) 50'3(a)(2)(viii)(A) 50.73(a)(2)(viii)(B) 50.73(a)(2)(x) 73.71(c)OTHER(ScifpeylnAbstractbelowandinText,NRCForm366A)LICENSEECONTACTFORTHISLER(12)NAHEJohnT~St.Martin-Director, Operating Experience TELEPHONE NUMBER(IncludeAreaCode)(315)524-4446COHPLETEONELINEFOREACHCOMPONENT FAILUREDESCRIBED INTHISREPORT(13)CAUSESYSTEMCOMPONENT MANUFACTURER REPORTABLE TONPRDSCAUSESYSTEMCOMPONENT HANUFACTURER REPORTABLE TONPRDSSUPPLEMENTAL REPORTEXPECTED(14)YES(lfyes,completeEXPECTEDSUBHISSION DATE).XNDEXPECTEDSUBHISSIONDATE(15)MONTHDAYYEARABSTRACT(Limitto1400spaces,i.e.,approximately 15single-spaced typewritten lines)(16)OnFebruary17,1994,atapproximately 1421EST,withthereactoratapproximately 98l.steadystatepower,aturbinerunbackoccurredwhenoffsitepower34.5KVCircuit751waslost,causinglowvoltageonsafeguards busses14and18.TheControlRoomoperators performed theappropriate actionsofAP-TURB.2, "TurbineLoadReduction",

andverifiedthattheplantwasstabilized atapproximately 93%poweraftertherunbacksignalcleared.Theunderlying causeofthelossofpowertooffsite34.5KVCircuit751waslossofpowertoN234.5KVBusatoffsiteStation204.(ThiseventisNUREG-1022 (C)CauseCode.)Corrective actiontoprecluderepetition isoutlinedinSectionV(B).NRCFORH366(5-92)

NRCFORH366A(5.92)U.S.NUCLEARREGULATORY COHHISSION LICENSEEEVENTREPORT(LER)TEXTCONTINUATION APPROVEDBYOMBNO.3150-0104 EXPIRES5/31/95ESTIMATED BURDENPERRESPONSETOCOHPLYWITHTHISINFORMATION COLLECTION REQUEST:50.0HRS.FORWARDCOMMENTSREGARDIHG BURDENESTIHATETOTHEINFORHATION ANDRECORDSHANAGEMENT BRANCH(MNBB7714),U.STNUCLEARREGULATORY COHMISSION, WASHINGTON, DC20555-0001 ANDTOTHEPAPERWORK REDUCTION PROJECT(31/0-0104),

OFFICEOFMANAGEMENT ANDBUDGETWASHINGTON DC20503.FACILITYNAME(1)R.E.GinnaNuclearPowerPlantDOCKETNUHBER(2)050002449400500LERNUMBER(6)YEARSEQUENTIAL REVISIONPAGE(3)2OF9TEXT(Ifmorespaceisrequired, useadditional copiesofNRCForm366A)(17)I.PRE-EVENT PLANTCONDITIONS Theplantwasatapproximately 98~steadystatereactorpower.The"A"emergency dieselgenerator (D/G)wasinoperation forthemonthlyperiodictestofD/Gperformance, procedure PT-12',"Emergency DieselGenerator lA."The"A"D/GwasinManualvoltagecontrol,'nd electrically loaded,perPT-12.1,toapproximately twothousand(2000)kilowatts (KW),supplying powerto480voltACsafeguards busses14and18.TheD/Gwassynchronized totheoffsitedistribution system,andwasbackfeeding somepowertotheoffsiteelectrical distribution system.Theoffsitepowertotheplantwasasfollows:~Offsitepower34.5KVCircuit751waslineduptosupplypowertosafeguards busses14and18through12A34.5KV/4160Vtransformer andthroughthesafeguards busses4160V/480V transformers.

Inparallelwithoffsitepower,the"A"D/Gwasalsosupplying powertothesebusses.~Offsitepower34.5KVCircuit767wassupplying powertosafeguards busses16and17through12B34.5KV/4160Vtransformer andthroughthesafeguards busses4160V/480V transformers.

NRCFORM366A(5-92)

NRCFORM366A(5-92)U.S.NUCLEARREGULATORY COMMISSION LICENSEEEVENTREPORT(LER)TEXTCONTINUATION APPROVEDBYOMBNO.3150~0104EXPIRES5/31/95ESTIMATED BURDENPERRESPONSETOCOMPLYWITHTHISIHFORMATIONCOLLECTION REQUEST:50.0HRS.FORWARDCOMMENTSREGARDIHGBURDENESTIMATETOTHEINFORMATION ANDRECORDSMANAGEMENT BRANCH(MNBB7714),U.S.NUCLEARREGULATORY COMMISSION, WASHINGTON, DC20555-0001 ANDTOTHEPAPERWORK REDUCTIONPROJECT(3110-0104),

OFFICEOFMAHAGEMENT ANDBUDGETWASHINGTON DC20503.FACILITYNAME(1)R.E.GinnaNuclearPowerPlantDOCKETNUMBER(2)05000244'EAR 005--00LERNUMBER(6)SEQUENTIAL REVISIONPAGE(3)3OF9TEXT(Ifmorespaceisrequired, useadditional copiesofNRCForm366A)(17)II.DESCRIPTION OFEVENTA.DATESANDAPPROXIMATE TIMESOFMAJOROCCURRENCES:

~Februarystarted,P~Februaryisolated17,1994,1251EST:Monthlytestofthe"A"D/GwasperPT-12.117,1994,1421EST:Offsite34.5KVCircuit751wasfromtheelectrical distribution system.~February17,1994,1421EST:Turbinerunback.Eventdateandtime.February17,1994,1421EST:Discovery dateandtime.VFebruary17,1994,1422EST:ControlRoomoperators performed theappropriate actionsofAP-TURB.2, "TurbineLoadReduction,"

andstabilized theplant.~February17,1994,1444EST:Safeguards busses14and18resupplied fromoffsitepower34.5KVCircuit751.~Febiuary17,1994,2210EST:Plantwasrestoredtoapproximately 98~steadystatereactorpower.B.EVENT:OnFebruary17,1994,aproblemwasidentified intheRochester GasandElectric(RGEE)electrical distribution system.Anairtankona34.5KVcircuitbreakerwasleaking.Atapproximately 1420EST,RGEEEnergyOperations checkedthebusvoltagesattwooffsiteelectrical distribution stations(Station204andStation13A)andopenedtheaffectedcircuitbreaker(5X20452).

Thiswasastandardswitching operation thathasbeenperformed anumberoftimes.Uponopeningbreaker5X20452,¹234.5KVBusatStation204experienced ahighvoltagecondition.

Afterreceiving thehighvoltagealarm,¹234.5KVBustransformer breaker(2T20452) unexpectedly tripped,isolating

¹234.5KVBusfromtherestoftheelectrical distribution system.NRCFORM366A(5-92)

NRCFORH366A(5-92)U.S.NUCLEARREGULATORY COHHISSION LICENSEEEVENTREPORT(LER)TEXTCONTINUATION APPROVEOBYOHBNO.3150-0104 EXPIRES5/31/95ESTIHATED BURDENPERRESPONSETOCOHPLYWITHTHISINFORMATION COLLECTIOH REQUEST:50.0HRS~FORWARDCOMMENTSREGARDING BURDENESTIHATETOTHEINFORMATION ANDRECORDSHANAGEHENT BRANCH(HNBB7714),U.S.NUCLEARREGULATORY COMMISSION, WASHINGTON, DC20555-0001 ANDTOTHEPAPERWORK REDUCTION PROJECT(3140-0104),

OFFICEOFMANAGEMENT ANDBUDGETWASHINGTON DC20503.FACILITYNAME(1)R.E.GinnaNuclearPowerPlantDOCKETNUMBER(2)YEAR0500024494LERNUHBER(6)SEQUENTIAL

--005--REVISION00PAGE(3)4OF9TEXT(Ifmorespaceisrequired, useadditional copiesofNRCForm366A)(17)Theg234.5KVBussuppliesCircuit751,oneofthetwo34.5KVtransmission circuitsthatsuppliesoffsitepowertoGinnaStation.Therefore, apartiallossofoffsitepowertoGinnaoccurred, asCircuit751wasnowisolatedfromtherestoftheelectrical distribution system.Theotheroffsitepowersupply,from34.5KVCircuit767,wasunaffected andcontinued tosupplypowerto480Vsafeguards busses16and17.Circuit751andtheN234.5KVBuswiththeirconnected loadsremainedenergized bytheGinna"A"D/G,sincetheD/Ghadbeenparalleled totheoffsiteelectrical distribution systemviaCircuit751.However,withthe"A"D/GinManualvoltagecontrol,the"A"D/Gvoltageoutputwasreducedbytheelectrical loadsonN234.5KVbus,whichresultedinalowvoltagecondition onbusses14and18.Thisvoltagereduction resultedinactuation ofundervoltage relays,whichtrippedthenormalsupplybreakersto480Vbusses14and18.Trippingofthenormalsupplybreakerstobusses14and18isolatedthe"A"D/Gandbusses14and18fromCircuit751.The"A"D/Gvoltage(andthevoltageonbusses14and18)recovered toabovetheundervoltage relayactuation setpoints.

Coincident withthelowvoltageonbus14,lowvoltageoccurredonthe"B"Instrument Bus.Lowvoltageonthe"B"Instrument Busexistedforapproximately four(4)seconds.IAtapproximately 1421EST,withthereactoratapproximately 98%steadystatereactorpowerandlowvoltageonthe"B"Instrument Bus,theControlRoomreceivednumerousannunciator alarms.TheControlRoomoperators immediately determined thataturbinerunbackhadoccurred.

ThisrunbackwascausedbyoneoffourOvertemperature DeltaTemperature (OTDeltaT)channelsandoneoffourOverpower DeltaTemperature (OPDeltaT)channelsrunback'signals.

Thisrunbackdecreases turbineloadwhentherelaysdropout.TheControlRoomoperators responded totheannunciators, andimmediately performed theappropriate actionsofabnormaloperating procedure AP-TURB.2, "TurbineLoadReduction".

Theoperators observedthatthenormalsupplybreakersforbusses14and18hadopened,andthatthe"A"D/Gwassupplying powertobusses14and18.Loadonthe"A"D/Gstabilized atapproximately 500KW.NRCFORH366A(592) l NRCFORM366A(5-92)U.S.NUCLEARREGULATORY COMMISSION LICENSEEEVENTREPORT(LER)TEXTCONTINUATION APPROVEDBYOMBNO.3150.0104 EXPIRES5/3'1/95ESTIMATED BURDENPERRESPONSETOCOMPLYWITHTHISINFORMATION COLLECTION REQUEST:50.0HRS.FORWARDCOMMENTSREGARDING BURDENESTIMATETOTHEINFORMATION ANDRECORDSMANAGEMENT BRANCH(MHBB7714),U.S.NUCLEARREGULATORY COMMISSION, WASHINGTON, DC20555-0001 ANDTOTHEPAPERWORK REDUCTION PROJECT(3140-0104),

OFFICEOFMANAGEMENT ANDBUDGETWASHINGTON DC20503.FACILITYNAME(1)DOCKETNUMBER(2)LERNUMBER(6)YEARSEQUENTIAL REVISIONPAGE(3)R.E.GinnaNuclearPowerPlant0500024494--005--005OF9TEXT(Ifmorespaceisrequired, useadditional copiesofHRCForm366A)(17)Atapproximately 1422EST,EnergyOperations personnel telephoned theGinnaControlRoom,andnotifiedtheOperations ShiftSupervisor oftheswitching operations thathadoccurredatStation204andoftheunexpected lossofpowertoCircuit751.Circuit751hadbeenisolatedforapproximately ninety(90)seconds.TheControlRoomoperators stabilized theplantatapproximately 93%reactorpoweraftertherunbacksignalcleared.Atapproximately 1439EST,theoperators referredtoemergency restoration procedure ER-ELEC.1, "Restoration ofOffsitePower".Atapproximately 1444EST,usingthisprocedure, theControlRoomoperators closedthenormalsupplybreakerstobusses14and18,restoring offsitepowertobusses14and'18.The"A"D/Gwasthenshutdownandreturnedtonormalstandbystatus.Duetothereactorpowerdecreasefromtheturbinerunback,axialfluxdifference inthereactorcoreexceeded"penalty" limitsofTechnical Specification (TS)3.10.2.Theoperators subsequently reducedreactorpowertobelow90~tocomplywiththeactionrequirements ofTS3.10.2forlimitsonaxialfluxdifference.

Atapproximately 1511EST,apowerincreasebackto98'.reactorpowerwasinitiated, andthereactorwasatapproximately 98~steadystatereactorpoweratapproximately 2210ESTonFebruary17,1994'INOPERABLE STRUCTURES iCOMPONENTS ORSYSTEMSTHATCONTRIBUTEDTOTHEEVENT:NoneD.OTHERSYSTEMSORSECONDARY FUNCTIONS AFFECTED:

NoneE.METHODOFDISCOVERY:

Thiseventwasimmediately apparentduetoMainControlBoardannunciator alarmsandotherindications intheControlRoom.NRCFORM366A(5-92)

NRCFORM366A(5-92)U.S.NUCLEARREGULATORY COHHISSION LICENSEEEVENTREPORT(LER)TEXTCONTINUATION APPROVEDBYOHBNO.3150-0104 EXPIRES5/31/95ESI'IMATED BURDENPERRESPONSETOCOMPLYWITHTHISINFORMATION COLLECTION REOUEST:50.0HRS.FORWARDCOMMENTSREGARDING BURDENESTIHATETOTHEIHFORHATION AHDRECORDSMANAGEMENT BRANCH(MHBB7714),U.STNUCLEARREGULATORY COMMISSION, WASHINGTON, DC20555-0001, ANDTOTHEPAPERWORK REDUCTION PROJECT(3150-0'104),

OFFICEOFMANAGEMENT ANDBUDGETWASHINGTOH DC20503.FACILITYNAHE(1)R.E.GinnaNuclearPowerPlantDOCKETNUMBER(2)05000244LERNUMBER(6)YEARSEOUEHTIAL 94--005REVISION00PAGE(3)6OF9TEXT(Ifmorespaceisrequired, useedditionat copiesofHRCForm366A)(17)F.OPERATORACTION:TheControlRoomoperators immediately performed theappropriate actionsofAP-TURB.2 andverifiedthatthe"A"D/Gwasoperating properlyandthatbusses14and18wereenergized fromtheD/G.Theoperators restarted necessary equipment, including the"A"servicewaterpump.Theoperators notifiedhighersupervision andtheNRCResidentInspector.

Subsequently, theoperators restoredoffsitepowertobusses14and18.Theytransitioned toprocedure 0-5.1,"LoadReductions,"

andreducedpowerbelow90'duetoaxialfluxdifference inthereactorcore.Theoperators terminated thetestofthe"A"D/G,andthe."A"D/Gwasshutdownandreturnedtonormalstandbystatusperprocedure T-27.4,"DieselGenerator Operation."

G.SAFETYSYSTEMRESPONSES:

Electrical loadsonbusses14and18deenergized asdesigned, duetoanundervoltage condition onthebusses.Theoperators manuallyrestarted necessary loads,including the"A"servicewaterpump,atapproximately 1422EST.The"A"D/Gcontinued tosupplypowertobusses14and18untilrestoration ofoffsitepowertobusses14and18.Offsite34.5KVCircuit767continued tosupplypowertosafeguards busses16and17duringtheevent.CAUSEOFEVENTA.IMMEDIATE CAUSE:Theimmediate causeoftheturbinerunbackwasreceiptofturbinerunbacksignalsfromoneoffourOTDeltaTandOPDeltaTchannels.

B.INTERMEDIATE CAUSE:Theintermediate causeofreceiptofturbinerunbacksignalswaslowvoltageonthe"B"Instrument Bus,whichcausedtheturbinerunbackrelaysassociated withthe"B"Instrument Bustodropout.Thelowvoltageonthe"B"Instrument BuswasduetolowvoltageonMCC-1C,whichsuppliespowertothe"B"Instrument Bus.ThelowvoltageonMCC-1CwasduetolowvoltageonBus14,whichsuppliesMCC-1C.HRCFORH366A(5-92)

NRCFORH366A(5-92)U.S.NUCLEARREGULATORY COHHISSION L'ICENSEE EVENTREPORT(LER)TEXTCONTINUATION APPROVEDBYOHBNO.3150-0104 EXPIRES5/31/95ESTIMATED BURDENPERRESPONSETOCOHPLYlllTHTHISINFORMATION COLLECTION REQUEST:50.0HRS.FORllARDCOMMENI'S REGARDING BURDENESTIMATETOTHEINFORMATION ANDRECORDSHANAGEMENT BRANCH(HNBB7714),U.S.NUCLEARREGULATORY COHHISSION, IIASHINGTON, DC20555-0001 ANDTOTHEPAPERllORK REDUCTION PROJECT(3140-0104),

OFFICEOFHANAGEMENT ANDBUDGETlJASHINGTON DC20503.FACILITYNAME(1)DOCKETNUHBER(2)LERNUHBER(6)YEARSEQUENTIAL REVISIONPAGE(3)R.E.GinnaNuclearPowerPlant0500024494--005--007OF9TEXT(Ifmorespaceisrequired, useadditional copiesofNRCForm366A)(17)C.ROOTCAUSE:Theunderlying causeofthelowvoltageonBus14(andBus18)waslossofpowerto34.5KVCircuit751,duetolossofpowertog234.5KVbusatStation204.(ThiseventisNUREG-1022 (C)CauseCode,ExternalCause.)IV.ANALYSISOFEVENTThiseventisreportable inaccordance with10CFR50.73,LicenseeEventReportSystem,item(a)(2)(iv),whichrequiresareportof,"Anyeventorcondition thatresultedinamanualorautomatic actuation ofanyengineered safetyfeature(ESF),including thereactorprotection system(RPS)~"Theturbinerunbackwasanautomatic actuation oftheRPS,andthemanualstartofthe"A"servicewaterpumpwasanactuation ofanESF.Anassessment wasperformed considering boththesafetyconsequences andimplications ofthiseventwiththefollowing resultsandconclusions:

~Allreactorcontrolandprotection systemsperformed asdesigned, thuslimitingtheoveralleffectsoftheturbinerunbacktransient.

~The"A"D/Goperatedasdesignedbysupplying powertosafeguards busses14and18.~TheControlRoomoperators expeditiously stabilized theplantafterthetransient.

~Offsitepower34.5KVCircuit767wasstillinoperation supplying powertosafeguards busses16and17.Basedontheabove,itcanbeconcluded thatthepublic'shealthandsafetywasassuredatalltimes.NRCFORH366A(5-92)

NRCFORM366A(5-92)U.S.NUCLEARREGULATORY COMMISSION LICENSEEEVENTREPORT(LER)TEXTCONTINUATION APPROVEDBYOHBNO.3150.0104 EXPIRES5/31/95ESTIMATED BURDENPERRESPONSETOCOMPLYWITHTHISINFORMATIOH COLLECTION REQUEST:50.0HRS.FORWARDCOMMENTSREGARDIHG BURDENESTIMATETOTHEINFORMATION AHDRECORDSMANAGEMENT BRANCH(MHBB7714),U.S.NUCLEARREGULATORY COMMISSION, WASHINGTON, DC20555.0001 ANDTOTHEPAPERWORK REDUCTION PROJECT(3140-0104),

OFFICEOFMAHAGEMEHT ANDBUDGETWASHINGTON DC20503.FACILITYNAME(1)R.E.GinnaNuclearPowerPlantDOCKETNUMBER(2)05000244LERNUMBER(6)YEARSEOUEHTIAL 94005REVISION00PAGE(3)8OF9TEXT(Ifmorespaceisrequired, useadditional copiesofHRCForm366A)(17)V.CORRECTIVE ACTIONA.ACTIONTAKENTORETURNAFFECTEDSYSTEMSTOPRE-EVENT NORMALSTATUS:~Offsitepower34.5KVCircuit751wasrestoredbyautomatic reclosure oftransformer breaker2T20452atStation204'TheGinnaControlRoomoperators restoredoffsitepowertosafeguards busses14and18from34.5KVCircuit751.~The"A"D/Gwasshutdownandreturnedtonormalstandbystatus.~Reactorpowerwasrestoredtoapproximately 98~steadystatereactorpowerafterrestoring axialfluxdifference towithinoperating limits.B.ACTIONTAKENORPLANNEDTOPREVENTRECURRENCE:

~EnergyOperations hasreviewedtheapplicable offsiteelectrical distribution drawingsandswitching orders.~EnergyOperations hasmadechangesintheswitching orderstominimizetheprobability ofalossofpowertoCircuit751'EnergyOperations hasmadechangestothenotification procedures oftheswitching orderstoensuretheseactivities arecommunicated totheGinnaOperations ShiftSupervisor.

~Procedures affecting Circuit767and/orCircuit751willbeidentified andrevised,asnecessary, toensureappropriate activities arecommunicated toEnergyOperations.

NRCFORM366A(5-92)

NRCFORH366A(5-92)U.S.NUCLEARREGULATORY COMMISSION LICENSEEEVENTREPORT(LER)TEXTCONTINUATION APPROVEDBYOMBNO.3150.0104 EXPIRES5/31/95ESTIMATED BURDENPERRESPONSETOCOHPLYWITHTHISINFORMATION COLLECTIOH REQUEST:50.0HRS.FORWARDCOMMENTSREGARDIHG BURDENESTIHATETOTHEINFORMATION AHDRECORDSMAHAGEMEHT BRANCH(HHBB7714),U.S.NUCLEARREGULATORY COHMISSION, WASHINGTOH, DC20555-0001, ANDTOTHEPAPERWORK REDUCTION PROJECT(3150-0104),

OFFICEOFHANAGEHENT AHDBUDGETWASHINGTON DC20503.FACILITYNAHE(1)R.E.GinnaNuclearPowerPlantDOCKETNUHBER(2)05000244LERNUHBER(6)YEARSEQUENTIAL 94005REVISION00PAGE(3)9OF9TEXT(Ifmorespaceisrequired, useadditional copiesofHRCForm366A)(17)VI.ADDITIONAL INFORMATION A.FAILEDCOMPONENTS:

Therewerenofailedcomponents atGinnaStation.B.PREVIOUSLERsONSIMILAREVENTS:AsimilarLEReventhistorical searchwasconducted withthefollowing results:Nodocumentation ofsimilarLEReventswiththesamerootcauseatGinnaNuclearPowerPlantcouldbeidentified.

However,LER92-007andLER91-002weresimilareventswithdifferent rootcauses.C.SPECIALCOMMENTS:

NoneHRCFORH366A(5-92)