ML17328B014

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LER 91-004-00:on 910313,reactor Tripped as Result of Turbine Trip Generated by Moisture separator-reheater High Water Level Trip.Caused by Ice & Snow Damaging Transmission Lines. Insp Performed on Governor & Steam traps.W/910412 Ltr
ML17328B014
Person / Time
Site: Cook American Electric Power icon.png
Issue date: 04/12/1991
From: BLIND A A, CARTEAUX P F
INDIANA MICHIGAN POWER CO. (FORMERLY INDIANA & MICHIG
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-91-004, LER-91-4, NUDOCS 9104180309
Download: ML17328B014 (6)


Text

ACCELERATED STRIBUTION DEMONSTRATION SYSTEMREGULATORY INFORMATION DISTRIBUTION SYSTEM(RIDS)ACCESSION NBR:9104180309 DOC.DATE:

91/04/12,NOTARIZED:

NODOCKET¹FACIL:50-316 DonaldC.CookNuclearPowerPlant,Unit2,Indiana&05000316AUTH.NAME.AUTHORAFFILIATION CARTEAUX,P.F.

IndianaMichiganPowerCo.(formerly Indiana&MichiganEleBLIND,A.A.

IndianaMichiganPowerCo.(formerly Indiana&MichiganEleRECIP.NAME RECIPIENT AFFILIATION

SUBJECT:

LER91-004-00:on 910313,reactor trippedasresultofturbinetripgenerated bymoistureseparator-reheater highwaterleveltrip.Causedbyice&snowdamagingtransmission lines.Inspperformed ongovernor&steamtraps.W/910412 ltr.DISTRIBUTION CODE:IE22TCOPIESRECEIVED:LTR ENCLSIZE:TITLE:50.73/50.9 LicenseeEventReport(LER),ncidentRpt,etc.NOTESRECIPIENT IDCODE/NAME PD3-1LACOLBURN,T.

INTERNAL:

ACNWAEOD/DSP/TPABNRR/DET/ECMB 9HNRR/DLPQ/LHFB11 NRR/DOEA/OEAB NRR/DST/SELB SDPLBSD1REIE02ILE01EXTERNALEG&GBRYCEiJ~HNRCPDRNSICMURPHYiGACOPIESLTTRENCL1111221111111111111111331111RECIPIENT

'DCODE/NAME PD3-1PDAEOD/DOAAEOD/ROAB/DSP NRR/DET/EMEB 7ENRR/DLPQ/LPEB10 NRR/DREP/PRPBll NRR/DST/SICB 7ENRR/DST/SRXB SERES/DSIR/EIB LSTLOBBYWARDNSICMAYS,GNUDOCSFULLTXTCOPIESLTTRENCL111122111122111111111111NOTETOALL"RIDS"RECIPIENTS PLEASEHELPUSTOREDUCEiVASTE!CONTACTTHEDOCUMENTCONTROLDESK,ROOP,IPI-37(EXT.20079)TOELIMINATE YOURNAMEFROMDISTRIBUTION LISTSFORDOCUMENTS YOUDON'TNEED!FULLTEXTCONVERSION REQUIREDTOTALNUMBEROFCOPIESREQUIRED'TTR 31ENCL31 IndianaMichigan~

PowerCompany~CookNuclearPlarnOneCookPlaceBridgrnan.

Ml494066164655901April12,1991lMDIANANICHlGANPOWERUnitedStatesNuclearRegulatory Commission DocumentControlDeskRockville, Maryland20852Operating LicensesDPR-74DocketNo.50-316DocumentControlManager:Inaccordance withthecriteriaestablished by10CFR50.73entitledLicenseeEventReortinSstemthefollowing reportisbeingsubmitted:

91-004-00 Sincerely, vj.oeA.A.BlindPlantManagerAAB:sbAttachment c:D.H.Williams, Jr.A.B.Davis,RegionIIIE.E.Fitzpatrick P.A.BarrettB.F.Henderson R.F.KroegerB.Walters-Ft.'ayneNRCResidentInspector T.Colburn-NRCJ.G.KepplerM.R.PadgettG.Charnoff, Esq.DottieSherman,ANILibraryD.HahnINPOS.J.Brewer/B.P.

LauzauB.A.Svenssone10q13030g 910412PDRADOCK05000316PDRgpP NRCFORM366(669)tAPPROVEDOMBNO.3)504))04 EXPIRES:4/30/92ESTIMATED BURDENPERRESPONSETOCOMPLYWTHTHISLICENSEEEVENTREPORTILER)COMMENTSREGARDING BURDENESTIMATETOTHERECORDSINFORMATION COLLECTION REQUEST:50.0HRS.FORWARDANDREPORTSMANAGEMENT BRANCHIP630),V.S.NUCLEARREGULATORY COMMISSION, WASHINGTON, DC20555,ANDTOTHEPAPERWORK REDUCTION PROJECT(31504104),

OFFICEOFMANAGEMENT ANDBUDGET,WASHINGTON, OC20503.FACILITYNAME(1)D.C.CookNuclearPlant-Unit2DOCKETNUMBER(2)IIAE3ppppp316~pF04~JfeactorProtection SystemActuation DuetoIceandSnowDamainOff-SiteElectrical Transmission Lines.EVENTDATEIS)LERNUMBER(6)REPORTDATE(7)OTHERFACILITIES INVOLVED(4IMONTHDAYYEARYEARc)P?ISSOVENTIAL

?g4NVMSERr'cccREvtclore~a.;NVMSSRMONTHDAYYEARFACILITYNAMESDOCKETNUMBER(SI p5ppp03139'19100400041291p5pppOPERATING MODE(9)]POWERLEYEL100PO)~~"'P~Mk'"9"~V~c++':*20.402(S) 20.405(~)(1)Bl20.405(e)

(1)(ii)20A05(el(1)(iii)20A05(e)(I)(iv)20A06(~I(I)(r)20.406(cl 50.34(c)(1)50.$6(cl(2)50.73(e)(2)(I)50.7$(e)(2)(ii)50.73(eI(2)(iii)LICENSFECONTACTFORTHISLER(12150,73(~)(2)(iv)50.7$(~)(2)N)"50.73(e)(2)(vS)50.73(e)l2)(riiillAI 50.73(~)(2)(vBI)(B)50.73(~)(2)(x)THISREPORTISSUBMITTED PURSUANT70THERLOUIREMENTS OF10CFR(ItIChechoneotmoreofthefotlowfnf)

(1173.71(S)73.71(c)OTHERISpeclfyInAbttrectbelowenrflnText,HRCForm$68AINAMEP.F.Carteaux-SafetyandAssessment Superintendent TELEPHONE NUMBERAREACODE616465-5901COMPLETEONELINEFOREACHCOMPONENT FAILUREDESCRIBED INTHISREPORT(13)CAUSESYSTEMCOMPONENT MANUFAC.TURERORTABLTONPRDS9'&Yr.CAUSESYSTEMCOMPONENT MANUFAC.TVREREPORTABLTONPRDS87%&SUPPLEMENTAL REPORTEXPECTED(14)

YESIlfyet,completeEXPECTEDSVBhtISSIOII DATEINOABSTRACTILlmlttof400epecet,I.e.,epptoxlmetely frfteentingletpecetypewritten linn)(16)EXPECTEDSUBMISSION DATE(15I'H~ohcccivco.k%MONTHDAYYEAROnMarch13,1991at0651hours,theUnit2reactortrippedasaresultofaturbinetripgenerated byamoistureseparator-reheater (MSR)highwaterleveltrip.Theturbine-generator tripandreactortripwerearesultofoff-siteelectrical transmission systemdisturbances.

Iceandsnowdamaged765KVtransmission lineswhichcausedasignificant loadrejection onthemainturbine.Theclosingofthemainturbinecontrolvalvesinresponsetotheloadrejection createdaMSRpressuretransient whichactuatedtheMSRhighwaterleveltripandtrippedthemainturbineandreactor.Theplantwasstabilized inMode3.Abnormalities notedduringtheeventincludedtheelectronic overspeed tripoftheturbinedrivenauxiliary feedwater pump,closureofoneofthefourmainsteamisolation valves,andapparentslowclosureofthe¹4combinedintercept valve.Allequipment malfunctions werereviewedwithnounreviewed safetyquestions andthereactorwasreturnedcriticalonMarch15,1991at1113hours.NRCForm366(689)

NRCFORM366A(64)9)U.S.NUCLEARREGULATORY COMMISSION LICENSEEEVENTREPORT(LER)TEXTCONTINUATION APPROVED0MBNO.31500104EXPIRES:4/30/92ESTIMATED BURDENPERRESPONSETOCOMPLYWTHTHISINFORMATION COLLECTION REQUEST!50.0HRS.FORWARDCOMMENTSREGARDING BURDENESTIMATETOTHERECORDSANOREPORTSMANAGEMENT BRANCH(P4)30),U.S.NUCLEARREGULATORY COMMISSION, WASHINGTON, DC20555,ANDTOTHEPAPERWORK REDUCTION PROJECT(31504)104),

OFFICEOFMANAGEMENT ANDBUDGET,WASHINGTON, 0020503.FACILITYNAME(1)D.C.CookNuclearPlant-Unit2DOCKETNUMBER(2)LERNUMBER(6)SEQUENTIAL W'oRFYISIONNUM88R'OSSNUM88RPAGE(3)TEXT/I/moreepece/4rer/or)ed, oreeddio'one/P/RC Forrrr3664'4/(12)osooo31691004-0002QF04Conditions PriortoOccurrence Unit2inMode1at100percent,ofRatedThermalPower(RTP).DescritionofEventOnMarch13,1991at0651hours,theUnit2reactor(EIIS/JE) trippedasaresultofaturbine(EIIS/TA) tripgenerated byamoistureseparator-reheater (MSR)(EIIS/SB-MSR) highwaterleveltrip.Theturbine-generator tripandreactortripwerearesultofoff-siteelectrical transmission systemdisturbances.

Iceandsnowdamaged765KVtransmission (EIIS/FK) lineswhichcausedasignificant loadrejection onthemainturbine(greaterthan504steamflowwithnoload).Theclosingofthemainturbinecontrolvalves(EIIS/TA-FCV) inresponsetotheloadrejection createdaMoistureSeparator-Reheater (MSR)pressuretransient whichactuatedtheMSRhighwaterleveltripandtrippedthemainturbineandreactor.Thetimefromthemostsevereelectrical transient totheMSRhighleveltripwas11.5seconds.Themainturbinecontrol.system(EIIS/TA-HCU) includesaspeedgovernordrivenbygearsinthefrontstandardandreceivesinputsfromtheload-limiter, operating device,acceleration limiter,steampressurelimiter,andcontrol,valvepositionfeedback; Theacceleration limiter(EIIS/TA-SCO) preventstheturbinefromtrippingonoverspeed onaloadrejection byreactingmorequicklythanthegovernorandtherebylimitingthemaximumspeedreachedbytheturbine.Iftheturbineacceleration reaches47RPMpersecond,corresponding toa50%loadrejection, the,acceleration limiterwillclosethehighpressurecontrolvalvesandlowpressureintercept valves.IItisbelievedthatthe765KVlinedisturbances, priortotheturbinetrip,causedasignificant loadrejection andactuatedtheacceleration limiter.Theunequalclosingtimesofthecontrolvalvesandintercept valvescreatedaMSRpressuretransient whichliftedtheMSRsafetyvalvesandactuateda5-secondtimedelayedMSRhighleveltrip.Following theturbinetrip/reactor tripsequence,

[tuibine(EIIS/TA-TRB) trip,openingorthereactortripbreakers(EIIS/JE-BKR),

insertion ofreactorcontrolrods(EIIS/AA-ROD),

feedwater isolation (EIIS/JB),

andautomatic startingofthemotordrivenauxiliary feedwater pumps(EIIS/BA-P)],

Operations personnel immediately implemented Emergency Operating Procedure 2OHP4023.E-O'to verifyproperresponseoftheautomatic protection systemandtoassesplantconditions forindicated appropriated recoveryactions.NRCForm366A1669)

NRCFORMSeeA(689)U.SNUCLEARREGULATORY COMMISSION tLICENSEEEVENTREPORT(LER)'EXTCONTINUATION APPROVEDOMBNO.31500104EXPIRES:4/30/92ESTIMATED BUADENPERRESPONSETOCOMPLYWTHTHISINFOAMATION COLLECTION REOUEST:50.0HRS.FORWARDCOMMENTSREGARDING BURDENESTIMATETO,THERECORDSANDREPOATSMANAGEMENT BRANCH(P.530),U.S,NUCLEARREGULATORY COMMISSION, WASHINGTON, OC20555,ANDTOTHEPAPERWORK REDUCTION PROJECT(31500104).

OFFICEOFMANAGEMENT ANDBUDGET,WASHINGTON, DC20503.FACILITYNAME(1ID.C.CookNuclearPlant-Unit2DOCKETNUMBER(2)LERNUMBER(6)YEARSPSSEOUSNTIAL

@~/IIEVISION NUM88A'NA:NUM888PAGE(3)TEXT/Ifmom4Pooo/4/oqowod, 844oddrdono/HRC FomI36543)(IT)osooo3l691-004-00030F04Following themaingenerator tripandtransfertoreservefeed(EIIS/FK),

the345KVbusprovidedastablepowersupplyfortheUnit2auxiliary loads.AreviewoffaultrecordsforUnit1showedsystemupsetstoalesserdegree,asitwasnotdirectlylinkedtothe765KVbus.Abnormalities notedduringtheeventincludedtheelectronic overspeed tripoftheturbinedrivenauxiliary feedwater pump(EIIS/BA-P),

closureofoneofthefourmainsteamisolation valves(EIIS/SB-ISV),

andslowclosureoftheN4combinedintercept valve(EIIS/SB-ISV).

Theturbinedrivenauxiliary feedwater pumpwasimmediately resetandplacedinstandby.Themainsteamisolation valvewasbel'ieved tohavedriftedshutandwasreopenedwithinminutesofthetrip.TheN4combinedintercept slowclosurehasbeenattributed toanindication problemandnotvalveinoperability.

CauseofEventThecauseoftheeventwasiceandsnowdamaging765KVoff-siteelectrical transmission linesresulting inanelectrical disturbance beyondthecontrolcapability oftheunit.AnalsisofEventThisreportisbeingsubmitted inaccordance withl0CFR50.73,paragraph (a)(2)(iv),

asaeventthatresultedinanunplanned automatic actuation oftheEngineered SafetyFeatures, including theReactorProtection System.Theautomatic'rotection responses, including reactortripanditsassociated actuations wereverifiedtohavefunctioned properlyasaresultofthereactortripsignal.Theelectronic

.overspeed tripoftheTurbineDrivenAuxiliary feedwater pumpwasimmediately resetfromthecontrolroomanditisbelievedthat,thepumpwouldhavebeenavailable ifrequired.

TheMainSteamIsolation Valve,whichdriftedshut,wasreopenedwithinminutesofthetrip.Theslowclosureofthecombinedintercept valvewasattributed toalimitswitchwhichdidnotreflectactualvalveposition.

Basedontheabove,itisconcluded thattheeventdidnotconstitute anunreviewed safetyquestionasdefinedin10CFR50.59(a)(2)nordiditadversely impactthehealthandsafetyofthepublic.NRCForm366A(669)

NRCFORM366A(689)LICENSEEEVENTREPORT(LER)TEXTCONTINUATION

!APPROVED0MBNO.31500104EXPIRES:4/30/92ESTIL(ATED BURDENPERRESPONSETOCOMPLYWTHTHISINFORMATION COLLECTION REOUESTI50.0HRS.FORWARDCOMMENTSREGARDING BURDENESTIMATETOTHERECORDSANDREPORTSMANAGEMENT BRANCH(PJ)30),U.S.NUCLEARREGULATORY COMMISSION, WASHINGTON, DC20555,ANDTOTHEPAPERWORK REDUCTION PROJECT(31500104),

OFFICEOFMANAGEMENT ANDBUDGET,WASHINGTON, DC20503.FACILITYNAME(1)DOCKETNUMBER(21LERNUMBER(6)PAGE(3)D.C.CookNuclearPlant-Unit2TEXT/lfmomSOooo/4mqoksd,ooooddi)looo/

HRCFono36649/(17)Corrective ctionsYEARi?(gosooo31691SEOVENTIAI.

?.'o?NUMBER'Fc?I004REVISIONNUMBER0004OF04TurbineDrivenAuxiliary Feedwater Pump(TDAFP)ThecauseoftheTDAFPelectronic overspeed tripcouldnotbeconclusively determined.

Athroughreviewoftheeventandextensive testingdidnotrevealthereasonfortheoverspeed event.Posttriptestingincluded:

omeasurement'f theasfoundelectrical tripoinspection ofthegovernorvalvelinkageandstemforbindingorcorrosion oinspection ofthegovernoroilforwatercontamination oinspection ofsteamtrapsonthesteamsupplypipingoafunctional testoftheTDAFPelectronic overspeed.

Alltestsandinspections werenormal.MainSteamIsolation Valve(MSIV)ClosingAreviewofpastUnit1andUnit2tripsshowedseveralcaseswhereMSIVsdriftedofftheiropenseats,aswasthecaseonthisparticular tripwithMSIVs421and422.Thiswasthefirsttripidentified whereaMSIVclosedcompletely, butgiventhesecondary transient experienced, itisnotconsidered unusualthatthiswouldoccur.CombinedIntercept Valve44TheCombinedIntercept Valve44appearedtoslowcloseovera5minuteperiodasindicated byanintermediate valvepositionandthefactthattheTurbineEventsRecorderdidnotregisterthevalveasbeingclosed.Asacondition torestart,thevalvewastimedinthecloseddirection andyieldedavalueof1.2seconds.'t isbelievedthatasinglelimitswitchdidnotinitially close.ThislimitswitchwouldkeeptheopenlightlitandpreventtheTurbineEventsRecorderformindicating aclosedposition.

FailedComonentIdentification NonePreviousSimilarEventsNoneNRCFoim366A(BS9)