ML17262A322

From kanterella
Revision as of 12:14, 29 June 2018 by StriderTol (talk | contribs) (Created page by program invented by StriderTol)
Jump to navigation Jump to search
LER 90-018-00:on 901220,dropped Control Rod/Turbine Runback Occurred During Rod Control Exercises.Caused by Degraded Power Bridge Thyristor Suppression Filter Capacitors. Capacitors replaced.W/910121 Ltr
ML17262A322
Person / Time
Site: Ginna Constellation icon.png
Issue date: 01/21/1991
From: BACKUS W H, MECREDY R C
ROCHESTER GAS & ELECTRIC CORP.
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-90-018, LER-90-18, NUDOCS 9101290229
Download: ML17262A322 (14)


Text

ACCELERATED DISpPBUTION DEMONS'TION SYSTEMREGULATORY INFORMATION DISTRIBUTION SYSTEM(RIDS)ACCESSION NBR:9101290229 DOC.DATE:

91/01/21NOTARIZED:

NODOCKETFACIL:50-244 RobertEmmetGinnaNuclearPlant,Unit1,Rochester G05000244AUTH.NAMEAUTHORAFFILIATION BACKUS,W.H.

'ochester Gas&ElectricCorp.MECREDY,R.C.

Rochester Gas&ElectricCorp.RECIP.NAME RECIPIENT AFFILIATION R

SUBJECT:

LER90-018-00:on 901220,dropped controlrod/turbine runbackoccurredduringrodcontrolexercises.

Causedbydegradedpowerbridgethyristor supporession filtercapacitors.

Capacitors replaced.W/910121 ltr.DISTRIBUTION CODE:IE22TCOPIESRECEIVED:LTR ENCLlSIZE:TITLE:50.73/50.9 LicenseeEventReport(LER),Incide'nt Rpt,etc.NOTES:License Expdateinaccordance with10CFR2,2.109(9/19/72).

.05000244RECIPIENT IDCODE/NAME PD1-3LAJOHNSON,A INTERNALACNWAEOD/DSP/TPABNRR/DET/ECMB 9HNRR/DLPQ/LHFB11 NRR/DOEA/OEAB NRR/DSTSELB8DNRRDSSR'DREFILE02RGN1I.LE~0'1EXTERNAL:

EG&GBRYCE,J.H NRCPDRNSICMURPHY,G.A COPIESLTTRENCL111122111.1111111111111331111RECIPIENT IDCODE/NAME PD1-3PDAEOD/DOAAEOD/ROAB/DS PNRR/DET/EMEB 7ENRR/DLPQ/LPEB10 NRR/DREP/PRPB11 NRR/DST/SICB 7ENRR/DST/SRXB 8ERES/DSIR/EIB LSTLOBBYWARDNSICMAYS,GNUDOCSFULLTXTCOPIESLTTRENCL,111122111122111111111111/V'up~yvif2(CDSNOTETOALL"RIDS"RECIPIENTS:

DDPLEASEHELPUSTOREDUCEWASTE!CONTACTTHEDOCUMENTCONTROLDESK,ROOMPl-37(EXT.20079)TOELIMINATE YOURNAMEFROMDISTRIBUTION LISTSFORDOCUMENTS YOUDON'TNEED!FULLTEXTCONVERSION REQUIREDTOTALNUMBEROFCOPIESREQUIRED:

LTTR31ENCL31

"RPZFPi7ifi8",>VI "0'"'"'!'""'Ir"""(I (J<v~!P)v lilkz!"iivv ROCHESTER GASANDELECTRICCORPORATION

~89EASTAVENUE,ROCHESTER N.K14649-0001 ROBERTCMECREDYVicePrestdent CtnneetucteeiProduction TELEPHONE AREAcOOE71ts5462700January21,1991U.S.NuclearRegulatory Commission DocumentControlDeskWashington, DC20555

Subject:

LER90-018,DroppedControlRodDuringRodControlExercises CausesAutomatic Actuation ofRPS(i.e.TurbineRunback)R.E.GinnaNuclearPowerPlantDocketNo.50-244Inaccordance with10CFR50.73,LicenseeEventReportSystem,item(a)(2)(iv),

whichrequiredsreportof,"anyeventorcondition thatresultedinmanualorautomatic actuation ofanyEngineered SafetyFeature(ESF),including theReactorProtection System(RPS)",theattachedLicenseeEventReportLER90-018isherebysubmitted.

Thiseventhasinnowayaffectedthepublic'shealthandsafety.Vetrulyyours,xcoRobertC.MeredyU.S.NuclearRegulatory Commission RegionI475Allendale RoadKingofPrussia,PA19406GinnaUSNRCSeniorResidentInspector 9i01290229 95000244PDR@DOCKoPDRS J

NACoorNSslISAtlLICENSEEEVENTREPORT(LERIUANUCLIAAAIOVLATOA+

COW~AJOAOVI0OOOIINL$1440I0VIXSIAIIIJSIJSSfAcIuTYNAJJIIllR.E.GinnaNUclearPowerPlantOOCXITNVOOSIAQl0"6000SOo08111LIIOJDropControlRodDurinRodControlExerciseCausesAutomatic Actuation ofRPSi.e.Tur'VINfOATSIIILIANVUIIAltl1lf01TOATtIflOTNI1fACIurlllINVOLVIOItlUOIITUOAYTIAA,TtAAotovlvtrAL

~rVUOtlAovvovr~ArUooAUONTNOAYrtAAJACILITYNAUISOOCXITNVIJSIAISI 060002090900180001219106040OftAATINOIJOOtI~IfONI1LtvlL0SS.ASS4ISt.Alt4IIIII~$4ANlolllIItl'4AIQ4IIIIINI$4AMNIIIIINI

$4.oll41llllrltI.ootlrlISMIol11l~IMNIQI~S.f$41QIII~I.f$41Qllxl~4.$$4IQIIVOIt.f$4IQIINI~S.f$4IQllrl~I.f$4IQlloolIID$4)QIITNNW

~O.f$4IQIIUSIISISS.TSNIQI41 0TNIAIOUIAIUINTSOfISCf1$:ICfoooorvorovroorVUNrorrUSJIlllTNII1lfOATIIWSUITTIOfVANJANTTfAfIrolfit1lolOTNIAJSANXVAIAorooor~oroUorrfJoforLJJACI~$SIAJLICINtllCONTACTfOATNISLtAlltlWesleyH.BackusTechnical Assistant totheOperations ManagerTILtfUONINVUIIAAAIACOOI31524-44COJJfLITI ONILINCfOAIACNCOOJJONINT fAJLUAIOISC1I~IOINTNIIAlf01TIIIICAVSISrtftilCOUJONINT UANVfACTVAIAtfOATAILI TONJAOICAUStSTSflUCOUJONINT UANUfACTVAI1lfOATAILTONJAOSBJGAPW120YSVffLtNINTAL AIJO1TIXflCTIOIIOINOTllIIJroe.JNofrrNCXfCCTCOSVCJJISSION OATCJIxfICTIOWIUIIIION OATSIlIIUONTNCAYTtAAoscTAAcfJLrrvr4JJJONore.IA.roororrrvrrrf ATNorrrrrvrroooro IrprenrNo frrrrliltOnDecember20,1990at1321EST,withthereactorat,approximately 22%fullpower;aturbinerunbackoccurredduetoadroppedcontrolrod.TheControlRoomoperators performed theappropriate actionsofAbnormalProcedures AP-TURB.2 (Automatic TurbineRunback)andAP-RCC.2(RCC/RPIMalfunction) tostabilize theplant.TheControlRoomoperators manuallytrippedtheturbinetopreventreversepowertothegenerator.

Subsequently thexeactorwastakensubcritical, toaccomodate anticipated corrective maintenance

'ctivities.

TheMainSteamIsolation Valveswerethencloyedtolimitaplantcooldown.

rTheunderlying causeoftheeventwasattributed todegradedpowerbridgethyristor suppression filtercapacitoxs inthecircuitsupplying powertothestationaxy, movableandliftcoilsoftheaffectedcontrolrod.Corrective actionwastoreplacethedegradedcapacitors inthepowercabinetsupplying powertotheaffectedrod.N1Cfore%ISASI KIICfOrAtSSOAISOSIUCENSEEEVENTREPORT(LER)TEXTCONTINUATION U.S.NUCLEAIIIIEOULATOIIY COMMISSION rAffAOVEOOMSKOSISO&IOIEXfIREE.SISIISSfACILITYNAMEIIIR.E.GinnaNuclearPowerPlantTEXTIITANIIYNMAfNteyvtWf.tNfAINeenarNOMICAntt~SIIITIOOCXETNUMOEIIISIYSAA0500024490LEIINUMOEIIISISSOUSHTIAL IIMA018IISVISIOItNIJM~AOEISIOF'RE-EVENT PLANTCONDITIONS Thereactorwasatapproximately 224withtheturbinegenerator ontheline,producing approximately 80megawatts.

Thefollowing activities wereinprogress:

oPlantstartupwascontinuing fromthereactortripof12/11/90(LER90-013)andsubsequent reactortripof12/12/90(LER90-016).oTheInstrument andControl(I&C)Department wasintheprocessoftroubleshooting acontrolproblemwiththeControlBank"D"ControlRods.(WhenmanuallysteppingBank"D"ControlRodsouttocontrolReactorCoolantSystem(RCS)temperature, itwasobservedthattheBank"D"ControlRodssteppedoutto128steps,thensteppedin3steps(withtherodcontrolswitchstillheldintheoutposition)).

Aspartofthistroubleshooting effort,theIGCDepartment requested thatPeriodicTestprocedure PT-1(RodControlSystem)beperformed.

IIDESCRIPTION OPEVENTA.DATESANDAPPROXIMATE TIMESOPMAJOROCCURRENCES:

oDecember20,1990,1321EST:Eventdateandtime.oDecember20,1990,1321EST:Discovery dateandtime.oDecember20,1990,1321EST:ControlRoomoperators performtheappropriate actionsofAbnormalProcedures AP-TURB.2 (Automatic TurbineRunback)andAP-RCC.2(RCC/RPIMalfunction) tostabilize theplant.oDecember20,1990,1323EST:Turbinetrippedmanually.

itACSOIIMSSSAIAAtI

~~0NIICfetet55EA(545lLICENSEEEVENTREPORT{LER)TEXTCONTINUATION V.E.NVCLEAII1EOULATOIIY COMMISSION AffAOVEOOMENO5ISOWIOS'EXPIAE5.

5/SI/55fACILITYNAMEIIICOCKETNVMEEIIIEILEIINUMOEIIIllSSOU~NTIALttVttAASvtSION~thattA~AOEISIR.E.GinnaNuclearPowerPlantTExTAlm<<eN>>t>>teteetteee.

weetAse<<>>tHlscf<<tttHECATOIITI050002490-0180003oF08December20,1990,1338EST:ControlRoomoperators closebothMainSteamIsolation Valves(MSIVs)toterminate aRCScooldown.

00December20,1990,1344EST:Shutdownandcontrolrodswerefullyinsertedmanually, andbothreactortripbreakerswereopened.December20,1990,1345EST:Plantstabilized inhotshutdown.

B.EVENT:OnDecember20,1990,at1321EST,withthereactoratapproximately 22~fullpower,adroppedcontrolrod/turbine runbackoccurred.

ControlBank"C"ControlRodJ-10droppedapproximately thirty-eight (38)stepsintothecoreduringtheperformance ofPT-1.Theturbinerunbackreducedgenerator loadfromapproximately 80megawatts toapproximately 15megawatts.

TheControlRoomoperators performed theappropriate actionsofAP-TURB.2 (Automatic TurbineRunback)andAP-RCC.2(RCC/RPIMalfunction) tostabilize theplant.Subsequently',

at1323EST,theturbinewastrippedmanuallytopreventreversepowertothegenerator.

TheControlRoomoperators thenperformed theappropriate actionsofAP-TURB.1 (TurbineTripWithoutRxTripRequired).

At1329EST,withthereactoratapproximately 64fullpowerandthe"A"MainFeedwater PumprunningfeedingbothSteamGenerators (S/G)throughtheMainFeedwater Regulating Bypassvalves,the'IAIIMainFeedwater Pumptrippedonfeedpumpsealwaterlowdifferential pressure.

Themotordrivenauxiliary feedwater pumpsstartedautomatically (asdesigned) andreactorpowerwasreducedtoapproximately 34fullpowertoensurethatrequiredfeedwater flowwaswithinthecapacityoftheauxiliary feedwater pumps.

NRCfar~555AN4JIL'iCENSEE EVENTREPORT(LER)TEXTCONTINUATiON US.NUCLEARREOULA'TORY COMMI55ION

/AftROVEOOMENO5150&104E)lfIREE5/5II55fACILITYNAME111DOCKETNUMEER151vEARLERNUMEER1515~QU5NTIALNUM1AEVOIOHNUMEAfAOEIJIR.E.GinnaNuclearPowerPlantTEXTIF~<<eceN~.v<<O4SeeW'VRC f<<R4%i5IIITIosooo244900180004pFDuetothelowpowercondition andtosupporttrouble-shootingactivities, theShiftSupervisor conserva-tivelyorderedthecontrolandshutdownrodstobeinsertedintothecore,inaccordance withnormaloperating procedures.

Subsequently at1338ESTtheMSIVswereclosedtolimittheRCScooldown.

Thereactortripbreakerswereopenedat1344ESTandtheplantwasstabilized inhotshutdown.

CINOPERABLE STRUCTURES fCOMPONENTS fORSYSTEMSTHATCONTRIBUTED TOTHEEVENT:None.D.OTHERSYSTEMSORSECONDARY FUNCTIONS AFFECTED:

E.None.METHODOFDISCOVERY:

Theeventwasimmediately apparentduetoalarmsandindications intheControlRoom.OPERATORACTION.Subsequent totheturbinerunback,theControlRoomoperators performed theappropriate actionsof,AP-TURB.2andAP-RCC.2tostabilize theplant.Theturbinewasmanuallytrippedtopreventreversepowertothegenerator.

TheControlRoomoperators thenperformed theappropriate actionsofAP-TURB.1 andsubsequently, whenthemainfeedwater pumptripped,assuredauxiliary feedwater flowtoS/G,tookthereactorsubcritical byinserting.

allcontrolandshutdownrods,andopened-the reactortripbreakers.

Theplantwasthenstabilized

'inhotshutdown.

SAFETYSYSTEMRESPONSES:

None.NACfORM555A N1Cfarm$AAA($4$II.'ICENSEE EVENTREPORT{LER)TEXTCONTINUATION U4.NVCLEA11EOULATOAY COMMITEION 1Aff<<OVEOOMSNO$I$0&10iEhfIAES;SI$I4$fACILITYNAMEIllOCCAMETNUMIEIIIllYTA1LEIINUMOEIIIII$$QVCHTIALHVM1htVISKINV1AOE1$IR.E.GinnaNuclearPowerPlant'tEXTIftmme<<MCe<<noded.vM<<AHknMNIICfehh~<<IIltl,osooo24490018-0005OF08III.CAUSEOFEVE2FZA.IMMEDIATE CAUSE:Theautomatic turbinerunbackwas'aused bydroppedControlRodZ-10.B.INTERMEDIATE CAUSE:ThecausefordroppedControlRodJ-10isattributed toanoisyincomingpowersupplytoControlRodJ-,10'sstationary andmovablegrippercoils.Thenoisyincomingpowersupplyisattributed todegradedthyristor capacitors inthepowerbridgecircuitforthestationary, movableandliftcoils.AreviewofWestinghouse Technical Bulletin(NSD-TB-74-16),wasperformed, andthepowerbridgecircuitry wasanalyzed, supporting thisconclusion.

C.ROOTCAUSE:Theunderlying causeofthedegradedthyristor capacitors isattributed todecreased servicelifeduetoelevatedoperating temperatures forthecapacitors.

IV.ANALYSISOFEVENTTheeventisreportable inaccordance with10CFR50.73,LicenseeEvent,ReportSystem,item(a)(2)(iv),

whichrequiresreporting of,,"anyeventorcondition thatresultedinmanualorautomatic actuation ofanyEngineered SafetyFeature(ESF)including the,ReactorProtection System(RPS)",inthattheautomatic turbinerunbackfrom.thedroppedrodwasanautomatic actuation oftheRPS.Anassessment wasperformed considering boththesafetyconsequences andimplications ofthiseventwiththefollowing resultsandconclusions:

NAC101M$$4AMAM

<<ACSerm$eeA(94)IL'ICENSEE EVENTREPORT(LER)TEXTCONTINUATION V.S<<VCLEAIIAEOVLATOIIY COMMITNOII AOOIIOVEO OME<<0$I$0&104E)COIAES$/$1/$$SACILITYNAMEIIIOOCXETIIVMEEIIITILEIIHVINEIIIEI$OQVO<<TIAL gVM1oovrlorMOAJAOCIEIR.E.GinnaNuclearPowerPlantTExTIlI'ore<<roorteevoaf,vmoooeonslHlICAmt~'olIITlosooo24490018006OF08oPowerwasreducedautomatically tocompensate forthenegativereactivity.

ofthedroppedrod.oAllreactorcontrolandprotection systemsperformed asdesignedthuslimitingtheoveralleffectsofthetransient.

Thetransient wascomparedtothedroppedrodeventevaluated inSection15oftheGinnaUpdatedFinalSafetyAnalysis(UFSAR).Noassumptions specified inChapter15oftheUFSARwereviolatedduringthisevent.Basedontheabove,itcanbeconcluded thatthepublic'shealthandsafetywasassuredatalltimes.V.CORRECTIVE ACTIONA.ACTIONTAKENTORETURNAFFECTEDSYSTEMSTOPRE-EVENT NORMALSTATUS:0Thecontrolproblemwiththeundesired steppingofBank"D"controlrodswascausedbypreviously installed testequipment.

Thisequipment wasremovedandtherodcontrolsystemwastestedandverifiedtobeoperating properly.

0Theelectricians measuredtheresistance ofcontrolrodJ-10'sstationary, movableandliftcoils,andverifiedtheresistance wascorrectforhotshutdownconditions.

Meggering verifiednogroundsexisted.0TheISCDepartment checkedcoilpolarityandverifiedtherewerenoblownfuses.Theseactivities confirmed thatconditions whichnormallycausedroppedrods,withintheindustry, didnotexistforthisevent.<<ACOOIIM$OOA NRCEor>>EEEAI'llSACILITYNAMEIIIL'ICENSEE EVENTREPORT(LERITEXTCONTINUATION OOCXETNUMEERIllUS.NUCLEARREOULATORY COMMIEEION Al'1ROVEO OMENOlIE0-OI04 ERtlREE,E/EI4$R.E.GinnaNuclearPowerPlantTEXTIJF@areN>>ce>>~wt~NRCAnn~EIIITIosooo24490LERNUMEERIEISEQUENTIAL HVMI1018Ii'IV>>IONMIA-00~AOEIEI7oF080Tocorrect'he causeofdroppedrodJ-10,theI&CDepartment replacedthepowerbridgethyristor suppression filtercapacitors inthe'circuitsupplying powertothestationary, movableandliftcoilsofControlRodJ-10.B.ACTIONTAKENORPLANNEDTOPREVENTRECUEGUBTCE:

Astheunderlying causeoftheeventwasattributed topremature agingofthethyristor capacitors, thefollowing actionsarebeingplanned:oAllpowerbridgethyristor capacitors, inPowerCabinet1ACwerereplaced.

(ControlRodJ-10ispoweredfromthiscabinet).

0Allpowerbridgethyristor capacitors intheotherpowercabinets(feedingthestationary, movableandliftcoilsofallcontrolrods)willbereplacedduringthenextannualoutage.0Theneedtosetupaprogramfortheperiodicreplacement ofthesethyristor capacitors, basedontheirtimeinservice,willbeevaluated.

VI.ADDITIONAL INFORMATION A.FAILEDCOMPONENTS:

Thethyristor capacitors involvedwerepurchased fromWestinghouse ElectricCorporation,

'partnumber2383A34H01 (capacitor,

.5ufd,660VAC).Thesecapacitors hadbeenpreviously installed asasub-component ofFieldChangeKit,drawingNo.2379A94.81C101MEEEA<OAlI HHCSonsSSSA104SIL'ICENSEE EVENTREPORTILER)TEXTCONTINUATION U.S.HUCLSAII1SOULATOHY COMMISSIOH

/AttlIOVSOOMSHOSISOWIOOSHtIASS'SISIISSSACILITYHAMS111OOCXSYHUMSSHISIvSAIILSIIHUMSSIIISISSQUSHTIAL nvMIInnSSVISIQH~AOS'IS)R.E.GinnaNuclearPowerPlantraxrIISIIHoo<<oco<<<<oooo'oo

<<AsoosorHllcSons~S1Im050002490oF08B.'REVIOUSLERsONSIMILAREVENTS:C.AsimilarLEReventhistorical searchwasconducted with-thefollowing results:Nodocumentation ofsimilarLEReventswiththesamerootcauseatGinnaStationcouldbeidentified.

However,LER89-008wasasimilarevent,withnoknownrootcause.SPECIALCOMMENTS:

None.H1Ct0IIMSSSAlOA'll 11