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

ACCELERATED DOCUMENTDISTRIBUTION SYSTEMREGULARYINFORMATION DISTRIBUTIO YSTEM(RIDS)ACCESSION NBR:9307210099 DOC.DATE:

93/07/02NOTARIZED:

NODOCKET¹FACIL:50-.244 RobertEmmetGinnaNuclearPlant,Unit1,Rochester G05000244AUTP..NAME AUTHORAFFILIATION WIDAY,J.A.

PacificGasSElectricCo.RECIP.NAME RECIPIENT AFFILIATION LINVILLE,J.C.

Region1(Post820201)

SUBJECT:

Forwardsdescription ofactivities recontrolrodsysmalfunction on930629.Caused byminormisalignment betweencontrolrodsinGroup1&Group2ofbankD.Control rodswillbemaintained inmanualcontrol.DISTRIBUTION CODE:IE01DCOPIESRECEIVED:LTR ENCLSIZE:TITLE:General(50Dkt)-Insp Rept/Notice ofViolation ResponseNOTES:License Expdateinaccordance with10CFR2,2.109(9/19/72).

05000244RECIPIENT IDCODE/NAME PD1-3PD1NTERNAL:

AEOD/DEIB AEOD/DSP/TPAB DEDRONRR/DRCH/HHFB NRR/DRSS/PEPB NRR/PMAS/ILPB2 OED~~RGF~E02RGNlFILE01EXTERNAL':

EGGG/BRYCEgJ.H.

NSICCOPIESLTTRENCL11111111111111111111RECIPIENT IDCODE/NAME JOHNSON,A AEOD/DSP/ROAB AEOD/TTCNRR/DORS/OEAB NRR/DRIL/RPEB NRR/PMAS/ILPBl NUDOCS-ABSTRACT OGC/HDS1RES/HFBNRCPDRCOPIESLTTRENCL11111111111111111111NOTETOALL"RIDS"RECIPIENTS:

PLEASEHELPUSTOREDUCEWASTE!CONTACTTHEDOCUMENTCONTROLDESK,ROOMPi-37(EXT.504-2065)

TOELIMINATE YOURNAMEFROMDISTRIBUTION LISTSFORDOCUMENTS YOUDON'7NEED!TOTALNUMBEROFCOPIESREQUIRED:

LTTR22ENCL22 ROCHESTER GASANDELECTRICCORPORATION

~TONK$1>N89EASTAVENUE,ROCHESTER, N.Y.14649-0001 U.S.NuclearRegulatory Commission RegionIAttn:JamesC.LinvilleChief,ProjectsBranchNo.3DivisionofReactorProjects475Allendale RoadKingofPrussia,PA19406TfLfPHOhf AllfACOOf7la546.2700July2,1993

Subject:

RodControlSystemMalfunction R.E.GinnaNuclearPowerPlantDocketNo.50-244

DearMr.Linville:

Asrequested, Rochester GasandElectricistransmitting adescription oftheactivities relatedtotherodcontrolsystemmalfunction whichoccurredon6/29/93.Adescription oftheeventandthetroubleshooting efforts,ananalysisoftheimpactonsafety,andtheinterimactionstobeimplemented areincludedbelow.EventDescription:

On6/29/93,amalfunction intherodcontrolsystemcausedaminormisalignment betweenthecontrolrodsingroup1andgroup2ofbankD.BankDgroup1wasindicating 212stepsonitsstepcounterand216stepsontheMicroprocessor RodPositionIndication system(MRPI).BankDgroup2wasindicating 209stepsonitsstepcounterand204onMRPI.ThiscausedaRodControlUrgentFailurealarmwhichstoppedallautomatic andmanualrodmotion.(BankDcontains4rods,2ineachgroup.Therodsineachgrouparelocatedsymmetrically acrossthecore.Group1containsrodsC7andK7,group2containsrodsG3andG11.)Thetroubleshooting effortsaredescribed inAttachment 1.Effortstodetermine therootcausearecontinuing.

ImpactonSafety:ThniISeifiInIibiliTechSpec3.10.4.1requirestherodstobe"operable andpositioned withina12stepsoftheirgroupstepcounterdemandposition".

Thesafetyfunctionofthecontrolrodsistoshutdownthereactoruponinitiation ofareactortripsignal.Controlrodmovementviatherodcontrolsystemisacontrolfunctionandisnotrequiredfortherodstobeconsidered operable.

StandardTechSpecsdefinesoperability foracontrolrodasbeingtripable.

Therefore, aslongastherodsaretripabletheyareoperable.

BothfluxmaptracesandMRPIindicated thattherodsweremovingwhenademandsignalwaspresent.Thisprovesthatthe1Gin~93072i0099 930702PDRADOCN05000244SPDR':(+r)P rodswerenot"immovable asaresultofexcessive frictionormechanically untripable" andtherefore wereoperable.

Sincethealignment specification wasalsomet,TechSpec3.10.4.1wasfullysatisfied.

TechSpec3.10.1.1specifies theshutdownmarginthatmustbemaintained.

TechSpec3.10.1.3specifies thatthecontrolrodsmustbemaintained abovetheRodInsertion Limits(RIL).TheRILfor100%poweris184stepsonBankD.Themaximumrodinsertion wasBankDat205steps.Therefore, TechSpec3.10.1.3wassatisfied.

SinceTavgwasonprogram,andtherodsweremaintained abovetheRIL,theshutdownmarginrequirement wasalsomet.Basedonthisevaluation, thecontrolrodswereoperableatalltimesandallTechSpecsweresatisfied.

PIdMalfninneuncTheBankDrodsaremaintained nearthefullywithdrawn positioninordertomaintainaxialoffsetwithinitstargetbandasrequiredbyTechSpecs.Evenifuncontrolled rodwithdrawal weretooccur(ie.urgentfailurealarmdidnotstoprodmotion),therewouldbeaverysmallpositivereactivity additionsinceBankDrodsareinalowworthregion.Inaddition, sincethemalfunction resultedinmovementofagroupofrodsratherthanasinglerod,coresymmetrywouldbemaintained andthepeakingfactorswouldbelesssevere,Thisisconsistent withthelicensing basisforGinnaasdescribed inUFSARsection15.4.2,Uncontrolled RCCAWithdrawal atPower.InterimActions:Untilthereisreasonable assurance thatthecauseoftherodcontrolproblemhasbeencorrected, thefollowing actionswillbetaken.Thecontrolrodswillbemaintained inmanualcontrol.TheBankDrodswillbeexercised dailytoensuretherodcontrolsystemisfunctioning properly.

Thetemperature, intheareaoftherodcontrolcabinets, atwhichventilation willbeincreased hasbeenreduced-from 92'Fto85'Finanattempttomitigatepotential temperature relatedeffects.Thisdirection hasbeenprovidedtoOperations throughthedailyoperations plan.Verytrulyyours,~i~d.MJosepA.WidayJPW/001attachment xc:Mr.AllenR.Johnson(MailStop14D1)ProjectDirectorate l-3Washington, D.C.20555U.S.NuclearRegulatory Commission RegionI475Allendale RoadKingofPrussia,PA19406GinnaSeniorResidentInspector Attachment 1Sub-~e:BankDGroup1RodControlProblemOnJune29,1993at2100hourswiththeplantoperating at97.54powerandnormalsteadystatecondition aRodControlurgentfailureRodStop(C30)alarmwasreceivedwhenControlBank"D"steppedinresponsetoanAutomatic Zndemandsignal.RodControlSystemindication priortoandafterreceiptoftheRodControlUrgentFailureAlarmwasasfollows:Prior:BankDGroup1counterat211stepsGroup2counterat210steps~Afte:-BankDGroup1counterat212stepsGroup2counterat209stepsUrgentAlarminLogicCabinetDS1lightliton1BDSlaveCyclerprintedcircuitcardlocationA-414inLogicCabinet.Lightindicates aslavecyclerfault.BankOverlapcounterat601stepsMRPIindication forBankDGroup1Rods(K7andC7)was216steps.MPRIIndication forBankDGroup2Rods(G3andG11)was204steps.Ambienttemperature inthevicinityoftheRodControlCabinetswasapproximately 87degreesF.atthetimetheproblemoccurred.

TroubosandResuts:SetupaVisicorder tomonitorBankDGroup1"Lift","Moveable",

and"Stationary" Coilvoltages.

Requested Operations resetRod.ControlUrgentFailureAlarm.Requested Operations tostepBankD"IN"onestepwhilemonitoring coilvoltageswithvisicorder.

BothGroupsmovedonestepinandVisicorder tracesofcoilvoltagesshowedpropersignalsequencing.

Requested Operations tostepBankD"IN"afewstepsand"OUT"afewsteps.Thiswasrepeatedthreetimeswithbothgroupsresponding properly.

Visicorder tracesofcoilvoltagesshowedpropersignalsequencing forboth"IN"and"OUT"motion.Temperature inthevicinityoftheRodControlCabinetsattimeoftestingwas73degreesF.Reduction intemperature causedbyincreased ventilation.

RodControlIndication atthecompletion oftheaboveRodtesting.was:0BankDGroup1Counterat212stepsGroup2Counterat209steps0.BankDP/Aconverter at,212stepsPerprocedure guidance0'perations realigned BankDGroup1rods'ithBankDGroup2rodsat209steps,verifiedP/Aconverter BankDindication wasat209steps,andhadI&CpositionBankoverlapcounterat599steps.Operations satisfactorily performed procedure PT-1(RodControlSystem)whichverifiedoperability ofallcontrolrods.

OnJune30,1993,analysisoftheproblemcontinued.

ContactwasmadewithWestinghouse toinformthemofourproblemandtoalsoobtaintheirassistance.

Afterseveralconversations andalotofresearchthefinalconsensus wasthatthesupervisory LogicIIprintedcircuit'wasthemostprobablecauseoftheproblem.Thesupervisory LogicIIcardprovides(1)ABufferMemoryControlCircuitwhichacceptsinputcommands, (2)FeedstheMasterCyclerwhichgenerates the"Go"pulsesforrodmovement, (3)FeedstheBankOverlapCircuitfordataloggingand(4)OutputstotheSlaveCyclerwhichgenerates currentordersforRodMovement.

Operations performed procedure PT-1(RodControlSystem)procedure'o verifyoperability ofallcontrolrods.Duringtheperformance ofprocedure PT-1,ISCpersonnel obtainedrecordings ofthevoltagesforGroupCounterCoilswhilesteppingtheGroupCountersfor"IN"and"OUT"movements toensurethathighvoltagespikeswerenotbeingfedbackintotheLogicCabinet(aswasexperienced atSalem).AllvoltageswerenormalwhichprovedthediodesacrosstheGroupCountercoilswereperforming theirintendedfunction.

RG&EandWestinghouse weresatisfied thatGinnadoesnothavethesameproblemasSalem;because(1)Salem'sproblemaffectedonlyoneRodClusterwhereGinna'saffectedthewholegroup,(2)Salemdidn'treceiveanurgentfailurealarm,(3)Salem'sproblempersisted whileGinna'sProblemoccurredonlyonce,and(4)Salem'sproblemwastheSlaveCyclerDecoderCardwhereGinna'sproblemisupstreaminthat.logic.OnJuly1,1993,thesupervisory LogicIIprintedCircuitCardwasreplacedandOperations successfully completed procedure PT-1(RodControlSystem)forprovingoperability ofallcontrolrods.