ML17263A315

Forwards Description of Activities Re Control Rod Sys Malfunction on 930629.Caused by Minor Misalignment Between Control Rods in Group 1 & Group 2 of Bank D.Control Rods Will Be Maintained in Manual Control

ML17263A315
Person / Time
Site:	Ginna
Issue date:	07/02/1993
From:	WIDAY J A PACIFIC GAS & ELECTRIC CO.
To:	LINVILLE J C NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
NUDOCS 9307210099
Download: ML17263A315 (6)

Text

ACCELERATEDDOCUMENTDISTRIBUTIONSYSTEMREGULARYINFORMATIONDISTRIBUTIOYSTEM(RIDS)ACCESSIONNBR:9307210099DOC.DATE:93/07/02NOTARIZED:NODOCKET¹FACIL:50-.244RobertEmmetGinnaNuclearPlant,Unit1,RochesterG05000244AUTP..NAMEAUTHORAFFILIATIONWIDAY,J.A.PacificGasSElectricCo.RECIP.NAMERECIPIENTAFFILIATIONLINVILLE,J.C.Region1(Post820201)

SUBJECT:

Forwardsdescriptionofactivitiesrecontrolrodsysmalfunctionon930629.CausedbyminormisalignmentbetweencontrolrodsinGroup1&Group2ofbankD.Controlrodswillbemaintainedinmanualcontrol.DISTRIBUTIONCODE:IE01DCOPIESRECEIVED:LTRENCLSIZE:TITLE:General(50Dkt)-InspRept/NoticeofViolationResponseNOTES:LicenseExpdateinaccordancewith10CFR2,2.109(9/19/72).05000244RECIPIENTIDCODE/NAMEPD1-3PD1NTERNAL:AEOD/DEIBAEOD/DSP/TPABDEDRONRR/DRCH/HHFBNRR/DRSS/PEPBNRR/PMAS/ILPB2OED~~RGF~E02RGNlFILE01EXTERNAL':EGGG/BRYCEgJ.H.NSICCOPIESLTTRENCL11111111111111111111RECIPIENTIDCODE/NAMEJOHNSON,AAEOD/DSP/ROABAEOD/TTCNRR/DORS/OEABNRR/DRIL/RPEBNRR/PMAS/ILPBlNUDOCS-ABSTRACTOGC/HDS1RES/HFBNRCPDRCOPIESLTTRENCL11111111111111111111NOTETOALL"RIDS"RECIPIENTS:PLEASEHELPUSTOREDUCEWASTE!CONTACTTHEDOCUMENTCONTROLDESK,ROOMPi-37(EXT.504-2065)TOELIMINATEYOURNAMEFROMDISTRIBUTIONLISTSFORDOCUMENTSYOUDON'7NEED!TOTALNUMBEROFCOPIESREQUIRED:LTTR22ENCL22 ROCHESTERGASANDELECTRICCORPORATION~TONK$1>N89EASTAVENUE,ROCHESTER,N.Y.14649-0001U.S.NuclearRegulatoryCommissionRegionIAttn:JamesC.LinvilleChief,ProjectsBranchNo.3DivisionofReactorProjects475AllendaleRoadKingofPrussia,PA19406TfLfPHOhfAllfACOOf7la546.2700July2,1993

Subject:

RodControlSystemMalfunctionR.E.GinnaNuclearPowerPlantDocketNo.50-244

DearMr.Linville:

Asrequested,RochesterGasandElectricistransmittingadescriptionoftheactivitiesrelatedtotherodcontrolsystemmalfunctionwhichoccurredon6/29/93.Adescriptionoftheeventandthetroubleshootingefforts,ananalysisoftheimpactonsafety,andtheinterimactionstobeimplementedareincludedbelow.EventDescription:On6/29/93,amalfunctionintherodcontrolsystemcausedaminormisalignmentbetweenthecontrolrodsingroup1andgroup2ofbankD.BankDgroup1wasindicating212stepsonitsstepcounterand216stepsontheMicroprocessorRodPositionIndicationsystem(MRPI).BankDgroup2wasindicating209stepsonitsstepcounterand204onMRPI.ThiscausedaRodControlUrgentFailurealarmwhichstoppedallautomaticandmanualrodmotion.(BankDcontains4rods,2ineachgroup.Therodsineachgrouparelocatedsymmetricallyacrossthecore.Group1containsrodsC7andK7,group2containsrodsG3andG11.)ThetroubleshootingeffortsaredescribedinAttachment1.Effortstodeterminetherootcausearecontinuing.ImpactonSafety:ThniISeifiInIibiliTechSpec3.10.4.1requirestherodstobe"operableandpositionedwithina12stepsoftheirgroupstepcounterdemandposition".Thesafetyfunctionofthecontrolrodsistoshutdownthereactoruponinitiationofareactortripsignal.Controlrodmovementviatherodcontrolsystemisacontrolfunctionandisnotrequiredfortherodstobeconsideredoperable.StandardTechSpecsdefinesoperabilityforacontrolrodasbeingtripable.Therefore,aslongastherodsaretripabletheyareoperable.BothfluxmaptracesandMRPIindicatedthattherodsweremovingwhenademandsignalwaspresent.Thisprovesthatthe1Gin~93072i0099930702PDRADOCN05000244SPDR':(+r)P rodswerenot"immovableasaresultofexcessivefrictionormechanicallyuntripable"andthereforewereoperable.Sincethealignmentspecificationwasalsomet,TechSpec3.10.4.1wasfullysatisfied.TechSpec3.10.1.1specifiestheshutdownmarginthatmustbemaintained.TechSpec3.10.1.3specifiesthatthecontrolrodsmustbemaintainedabovetheRodInsertionLimits(RIL).TheRILfor100%poweris184stepsonBankD.ThemaximumrodinsertionwasBankDat205steps.Therefore,TechSpec3.10.1.3wassatisfied.SinceTavgwasonprogram,andtherodsweremaintainedabovetheRIL,theshutdownmarginrequirementwasalsomet.Basedonthisevaluation,thecontrolrodswereoperableatalltimesandallTechSpecsweresatisfied.PIdMalfninneuncTheBankDrodsaremaintainednearthefullywithdrawnpositioninordertomaintainaxialoffsetwithinitstargetbandasrequiredbyTechSpecs.Evenifuncontrolledrodwithdrawalweretooccur(ie.urgentfailurealarmdidnotstoprodmotion),therewouldbeaverysmallpositivereactivityadditionsinceBankDrodsareinalowworthregion.Inaddition,sincethemalfunctionresultedinmovementofagroupofrodsratherthanasinglerod,coresymmetrywouldbemaintainedandthepeakingfactorswouldbelesssevere,ThisisconsistentwiththelicensingbasisforGinnaasdescribedinUFSARsection15.4.2,UncontrolledRCCAWithdrawalatPower.InterimActions:Untilthereisreasonableassurancethatthecauseoftherodcontrolproblemhasbeencorrected,thefollowingactionswillbetaken.Thecontrolrodswillbemaintainedinmanualcontrol.TheBankDrodswillbeexerciseddailytoensuretherodcontrolsystemisfunctioningproperly.Thetemperature,intheareaoftherodcontrolcabinets,atwhichventilationwillbeincreasedhasbeenreduced-from92'Fto85'Finanattempttomitigatepotentialtemperaturerelatedeffects.ThisdirectionhasbeenprovidedtoOperationsthroughthedailyoperationsplan.Verytrulyyours,~i~d.MJosepA.WidayJPW/001attachmentxc:Mr.AllenR.Johnson(MailStop14D1)ProjectDirectoratel-3Washington,D.C.20555U.S.NuclearRegulatoryCommissionRegionI475AllendaleRoadKingofPrussia,PA19406GinnaSeniorResidentInspector Attachment1Sub-~e:BankDGroup1RodControlProblemOnJune29,1993at2100hourswiththeplantoperatingat97.54powerandnormalsteadystateconditionaRodControlurgentfailureRodStop(C30)alarmwasreceivedwhenControlBank"D"steppedinresponsetoanAutomaticZndemandsignal.RodControlSystemindicationpriortoandafterreceiptoftheRodControlUrgentFailureAlarmwasasfollows:Prior:BankDGroup1counterat211stepsGroup2counterat210steps~Afte:-BankDGroup1counterat212stepsGroup2counterat209stepsUrgentAlarminLogicCabinetDS1lightliton1BDSlaveCyclerprintedcircuitcardlocationA-414inLogicCabinet.Lightindicatesaslavecyclerfault.BankOverlapcounterat601stepsMRPIindicationforBankDGroup1Rods(K7andC7)was216steps.MPRIIndicationforBankDGroup2Rods(G3andG11)was204steps.AmbienttemperatureinthevicinityoftheRodControlCabinetswasapproximately87degreesF.atthetimetheproblemoccurred.

TroubosandResuts:SetupaVisicordertomonitorBankDGroup1"Lift","Moveable",and"Stationary"Coilvoltages.RequestedOperationsresetRod.ControlUrgentFailureAlarm.RequestedOperationstostepBankD"IN"onestepwhilemonitoringcoilvoltageswithvisicorder.BothGroupsmovedonestepinandVisicordertracesofcoilvoltagesshowedpropersignalsequencing.RequestedOperationstostepBankD"IN"afewstepsand"OUT"afewsteps.Thiswasrepeatedthreetimeswithbothgroupsrespondingproperly.Visicordertracesofcoilvoltagesshowedpropersignalsequencingforboth"IN"and"OUT"motion.TemperatureinthevicinityoftheRodControlCabinetsattimeoftestingwas73degreesF.Reductionintemperaturecausedbyincreasedventilation.RodControlIndicationatthecompletionoftheaboveRodtesting.was:0BankDGroup1Counterat212stepsGroup2Counterat209steps0.BankDP/Aconverterat,212stepsPerprocedureguidance0'perationsrealignedBankDGroup1rods'ithBankDGroup2rodsat209steps,verifiedP/AconverterBankDindicationwasat209steps,andhadI&CpositionBankoverlapcounterat599steps.OperationssatisfactorilyperformedprocedurePT-1(RodControlSystem)whichverifiedoperabilityofallcontrolrods.

OnJune30,1993,analysisoftheproblemcontinued.ContactwasmadewithWestinghousetoinformthemofourproblemandtoalsoobtaintheirassistance.AfterseveralconversationsandalotofresearchthefinalconsensuswasthatthesupervisoryLogicIIprintedcircuit'wasthemostprobablecauseoftheproblem.ThesupervisoryLogicIIcardprovides(1)ABufferMemoryControlCircuitwhichacceptsinputcommands,(2)FeedstheMasterCyclerwhichgeneratesthe"Go"pulsesforrodmovement,(3)FeedstheBankOverlapCircuitfordataloggingand(4)OutputstotheSlaveCyclerwhichgeneratescurrentordersforRodMovement.OperationsperformedprocedurePT-1(RodControlSystem)procedure'overifyoperabilityofallcontrolrods.DuringtheperformanceofprocedurePT-1,ISCpersonnelobtainedrecordingsofthevoltagesforGroupCounterCoilswhilesteppingtheGroupCountersfor"IN"and"OUT"movementstoensurethathighvoltagespikeswerenotbeingfedbackintotheLogicCabinet(aswasexperiencedatSalem).AllvoltageswerenormalwhichprovedthediodesacrosstheGroupCountercoilswereperformingtheirintendedfunction.RG&EandWestinghouseweresatisfiedthatGinnadoesnothavethesameproblemasSalem;because(1)Salem'sproblemaffectedonlyoneRodClusterwhereGinna'saffectedthewholegroup,(2)Salemdidn'treceiveanurgentfailurealarm,(3)Salem'sproblempersistedwhileGinna'sProblemoccurredonlyonce,and(4)Salem'sproblemwastheSlaveCyclerDecoderCardwhereGinna'sproblemisupstreaminthat.logic.OnJuly1,1993,thesupervisoryLogicIIprintedCircuitCardwasreplacedandOperationssuccessfullycompletedprocedurePT-1(RodControlSystem)forprovingoperabilityofallcontrolrods.