ML17263A310

Ro:On 930629,malfunction in Rod Control Sys Caused Minor Misalignment Between Control Rods in Group 1 & 2 of Bank D. Cause Under Investigation.Control Rods Will Be Maintained in Manual Control & Bank D Rods Will Be Exercised Daily

ML17263A310
Person / Time
Site:	Ginna
Issue date:	07/02/1993
From:	WIDAY J A ROCHESTER GAS & ELECTRIC CORP.
To:	LINVILLE J C NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
NUDOCS 9307090106
Download: ML17263A310 (12)

Text

ACCELERATEDOCUMENTDISTRIBUTIONSYSTEMREGULATINFORMATIONDISTRIBUTIOh+YSTEM(RIDE)ACCESSIORNBR:9307090106DOC.DATE:93/07/02NOTARIZED:NODOCKETFACIL:50-244RobertEmmetGinnaNuclearPlant,Unit1,RochesterG05000244AUTH.NAMEAUTHORAFFILIATIONWIDAYFJ.A.RochesterGas6ElectricC'orp.RECIP.NAMERECIPIENTAFFILIATIONLINVILLE,J.C.'egion1(Post820201)V

SUBJECT:

RO:on930629,malfunctioninrodcontrolsyscausedminormisalignmentbetweencontrolrodsinGroup1a2ofBankD.Causeunderinvestigation.Controlrodswillbemaintainedinmanualcontrol&BankDrodswillbeexerciseddaily.DISTRIBUTIONCODE:IE22DCOPIESRECEIVED:LTRENCLSIZE:TITLE:50.73/50.9LicenseeEventReport(LER),IncidentRpt,etc..NOTES:LicenseExpdateinaccordancewith10CFR2,2.109(9/19/72).05000244RECIPIENTIDCODE/NAMEPDl-3LAJOHNSON,AINTERNAL:ACNWAEOD/DSP/TPABNRR/DE/EELBNRR/DORS/OEABNRR/DRCH/HICBNRR/DRIL/RPEBNRRSPLBREGF02RGN1FILEOlEXTERNAL:EGGGBRYCEFJ.HNRCPDRNSICPOOREFW.COPIESLTTRENCL1111221111111111111111221111RECIPIENTIDCODE/NAMEPD1-3PDAEOD/DOAAEOD/ROAB/DSPNRR/DE/EMEBNRR/DRCH/HHFBNRR/DRCH/HOLBNRR/DRSS/PRPBNRR/DSSA/SRXBRES/DSIR/EIBLSTLOBBYWARDNSICMURPHYFG.ANUDOCSFULLTXTCOPIESLTTRENCL'11122111111221111111111DNOTETOALL"RIDS"RECIPIFN'I'S:PLEASEHELPUSTOREDUCEWASTE!CONTACTTHEDOCUMENTCONTROLDESK,ROOMPl-37(EXT.504-2065)TOELIMINATEYOURNAMEFROMDISTRIBUTIONLISTSFORDOCUMENTSYOUDON'TNEED!DTOTALNUMBEROFCOPIESREQUIRED:LTTR30ENCL30

eU.=-NRCGIDNAPl1ROCHESTERGASANDELECTRICCORPORATION~89EASTAVENUE.ROCHESTER,N.Y.146490001U.S.NuclearRegulatoryCommissionRegionIAttn:JamesC.LinvllleChief,ProjectsBranchNo.3DivisionofReactorProjects.475AlfendaleRoadKingofPrussia.PA19406July2,1993

Subject:

RodControlSystemMalfunctionR.E.GinnaNuclearPowerPlantDocketNo.50-244

DearMr.Linville:

IAsrequested,RochesterGasandElectricistransmittingadescriptionoftheactivitiesrelatedtotherodcontrolsystemmalfunctionwhichoccurredon6/29/93.Adescriptionoftheeventandthetroubleshootingefforts,ananalysisoftheimpactonsafety,andtheinterimactionstobeimplementedareIncludedbelow.EventDescrlptfon:On6/29/93,amalfunctionintherodcontrolsystemcausedeminormisalignmentbetweenthecontrolrodsingroup1andgroup2ofbankD.BankDgroup1wasindicating212stepsonitsstepcounterand216stepsontheMicroprocessorRodPositionIndicationsystem-(MRPI).BankDgroup2wssindicating209stepsonitsstepcountersnd204onMRPl.ThiscausedaRodControlUrgentFailurealarmwhichstoppedallautomaticandmanualrodmotion.<BankDcontains4rods,2ineachgroup.Therodsineachgrouparelocatedsymmetricallyacrossthecore.Group1containsrodsC7andK7,group2containsrodsG3andG11.lThetroubleshootingeffortsaredescribedinAttachment1.Effortstodeterminetherootcausearecontinuing.ImpactonSafety:9307090206930702PDRADOCK05000244SPDRT*TechSpec3.10.4.1requirestherodstobe"operableandpositionedwithinx12stepsoftheirgroupstepcounterdemandposition".Thesafetyfunctionofthecontrolrodsistoshutdownthereactoruponinitiationofareactortripsignal.Controlrodmovementvistherodcontrolsystemisacontrolfunctionandisnotrequiredfortherodstobeconsideredoperable.StandardTechSpecsdefinesoperabilityforacontrolrodasbeingtripsble.Therefore,sslongastherodsaretripabletheyareoperable.BothfluxmaptracesandMRPIindicatedthattherodsweremovingwhenademandsignalwaspresent.Thisprovesthatthe~/pP

rodswerenot"immovableasaresultofexcessivefrictionormechanicallyuntripable"andthereforewereoperable.Sincethealignmentspecificationwssalsomet,TechSpec3.10.4.1wasfullysatisfied.TechSpec3.10.1.1specifiestheshutdownmarginthatmustbemaintained.TechSpec3.10.1.3specifiesthatthecontrolrodsmustbemaintainedabovetheRodInsertionLimits(RIL).TheRILfor100%poweris184stepsonBankD.ThemaximumrodinsertionwasBankDat205steps.Therefore,TechSpec3.10.1.3wassatisfied.SinceTavgwasonprogram,andtherodsweremaintainedabovetheRIL,theshutdownmarginrequirementwasalsomet.4Basedonthisevaluation,thecontrolrodswereoperableatalltimesandallTechSpecsweresatisfied,PTheBankDrodsaremaintainednearthefullywithdrawnpositioninordertomaintainaxialoffsetwithinitstargetbandasrequiredbyTechSpecs.Evenifuncontrolledrodwithdrawalweretooccur(ie.urgentfailurealarmdidnotstoprodmotion),therewouldbeaverysmallpositivereactivityadditionsinceBankDrodsareinslowworthregion.Inaddition,sincethemalfunctionresultedinmovementofagroupofrodsratherthanasinglerod.coresymmetrywouldbemaintainedsndthepeakingfactorswouldbelesssevere.ThisisconsistentwiththelicensingbasisforGinnaasdescribedinUFSARsection1S.4.2,UncontrolledRCCAWithdrawalatPower.InterimActions:Untilthereisreasonableassurancethatthecauseoftherodcontrolproblemhasbeencorrected,thefollowingactionswillbetaken.Thecontrolrodswillbemaintainedinmanualcontrol.TheBank0rodswillbeexerciseddailytoensuretherodcontrolsystemisfunctioningproperly.Thetemperature,intheareaoftherodcontrolcabinets,atwhichventilationwillbeincreasedhasbeenreducedfrom92'Fto85'Finanattempttomitigatepotentialtemperaturerelatedeffects.ThisdirectionhasbeenprovidedtoOperationsthroughthedailyoperationsplan.VeryulyyourJPW/001attachmentJoseph.WidayXC:Mr.AllenR.Johnson(MailStop14D1)Pro}ectDirectorateI-3Washington,D.C.20555U.S.NuclearRegulatoryCommissionRegionI475AllendaleRoadKingofPrussia.PA19406GinnaSeniorResidentInspector

Attachment1Rlhji~-'ankDGioup1RodControlProblemOnJune29,1993at2100hourswiththeplantoperatingat97.54powerandnormalstoadystateconditionaRodControlurgentfailureRodStop(C30)alarmwasreceivedwhenControlBank"D"steppedinrasponseto,anAutomaticlndomandsignal.RodControlSystemindicationpriortoandafterreceiptoftheRodControlUrgentPailureAlarmwasasfollows:BankDGroup1counterat211stepsGroup2counterat210stepsBankDGroup1counterat212stepsGroup2counterat209stepsUrgentAlarminLogicCabinetDS1lightliton1BDSlaveCyclerprintedcardlocationA-414inLogicCabinet.indicatesaslavecyclerfault.BankOverlapcounterat601stepscircuitLightMBPZindicationforBankDGroup1Rods(K7andC7)was216steps.MPRIIndicationforBankDGroup2Rods(63and611)was204stops.IAmbientteeperatureinthevicinityoftheRodControlCabinetswasapp~Mtely&7degreesF.atthetimetheproblemoccurred.

SetupaVisicordertomonitorBankDGroup1>Lift","Moveable",and"Stationary"Coilvoltages.RaquestodOperatiansresetRodControlUrgentFailureAlarm.RequestedOperationstostepBankD"IN"onestepwhilemonitoringcoilvaltageswithvisicorder.BothGroupsmovedonestepinandVisicordertracosofcoilvoltagesshowodprapersignalsequencing.RequestedOperatianstostepBankD"IN"afewstepsand"OUT"afewsteps.Thiswasrepeatedthreetimeswithbothgroupsrespondingprapexly,Visicardertracesofcoilvoltagesshowedpropersignalsequencingforboth"IN"and"OUT"motion.TemperatureinthevicinityoftheRodControlCabinetsattimeoftestingwas73degreesP.Reductionintemperaturecausedbyincreasedventilation.RodControlIndicationatthecompletianoftheaboveRodtestingwas:BankDGroup1Counterat212stepsGroup2Counterat209stepsBankDP/Aconverterat212stepsPerprocedureguidanceOperationsrealignedBankDGroup1rodswithBankDGroup2radsat209steps,verifiedP/AconverterBankDindicationwasat209steps,andhadICCpositionBankoverlapcounterat599steps.~ationssatisfactorilyperformedprocedurePT-1(RodCoatrolSystem)whichverifiedoperabilityofallcontrolRode~

jN OnJune30,1993,analysisoftheproblemcontinued.Contactwasmadewith4estinghoueetoinformthemofourproblemandtoalsoobtaintheirassistance.hfterseveralconversationsandalotofresearchthefinalconsensuswasthatthesupervisory.LogicXXprintedcircuitwasthemostprobablecausaoftheproblem.ThesupervisoryLogicXIcardprovides(1)ABufferMemoryControlCircuitwhichacceptsinputcommands,(2)FeodstheMastercyclerwhichgeneratesthe"Go",pulsosforrodmovement,(3)FeedstheBankOverlapCircuitfordataloggingand(4)OutputstotheSlaveCyclerwhichgeneratescurrentordersforRodMovement.OperationsperformedprocedurePT-1(RodControlSystem)proceduretoverifyoperabilityofallcontrolrods.DuringtheperformanceofprocedurepT-l,z&cpersonnelobtainedrecordingsofthevoltagesforGroupCounterCoilswhilestoppingtheCroupCountersfor"XN"and"OUT"movementstoensurethathighvoltagespikesvorenotbeingfedbackintotheLogicCabinet(aswas'experiencedatSalem).AllvoltagesverenormalwhichprovedthediodesacrosstheGroupCountercoilsvereperformingtheirintendedfunction.RGSEandWestinghouseveresatisfiedthatGinnadoesnothavethesameproblemasSalam;because(1)Salem'sproblemaffectedonlyoneRodclusterwhereGinna'saffectedthewholegroup,(2)Salemdidn'treceiveanurgontfailurealarm,(3)Salem'sproblemporsistedwhileGinna'sProblemoccurredonlyonce,and(i)Salem'sproblemwastheSlaveCyclerDecoderCardwhereGinna'8problemisupstreaminthatlogic.OnJuly1,1993,thesupervisoryLogicXIprintedCircuitCardwasreplacedandOperationssuccessfullycompletedprocedurePT-1(RodControlSystem)forprovingoperabilityofallcontrolrods.