ML17292A948

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LER 97-007-00:on 970611,voluntary Rept of Automatic Start of DG-1 & DG-2 Was Experienced.Caused by Undervoltage Condition on Electrical Busses SM-7 & SM-8.Circulating Water Pump CW-P-1C Control Switch Placed in pull-to-lock.W/970723 Ltr
ML17292A948
Person / Time
Site: Columbia Energy Northwest icon.png
Issue date: 07/23/1997
From: BEMIS P R, PFITZER B
WASHINGTON PUBLIC POWER SUPPLY SYSTEM
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
GO2-97-147, LER-97-007, LER-97-7, NUDOCS 9707300094
Download: ML17292A948 (7)


Text

~CATEGORY1~~REGULATORY INFORMATION DISTRIBUTIQNWYSTEM (RIDS)ACCESSION NBR:9707300094

'DOC.DATE:97/07/23NOTARIZED:

NOFACIL:50-3>>7WPPSSNuclearProJect.Unit2>Washington PublicPoreAUTH.NAMEAUTHORAFFILIATION PFITZEP>B.'ashington PublicPoeerSupp1!JS!JstemBEMIS>P.R.Washington P0bliePoeerSupp1!JS!JstemRECIP.NAMERECIPIENT AFFILIATION DOCKET005000397

SUBJECT:

LER97-007-00:

on'>>70611>

voluntar!J reptoFautomatic startoPDG-15DG-2wasexperienced.

Causedb!Jundervoltage condition onelectrical bussesSM-7bSM-8.Circulating eaterpumpCW-P-1Ccontrolswitcheasplacedinpull-to-lock.

DISTRIBUTION CODE:IE22TCOPIESRECEIVED:

LTRENCLSIZE:TITLE:50.73/50.9LicenseeEventReport(LER)>IncidentRpt>etc.NOTES:RECIPIENT IDCODE/NAME PD4-2PDCQPIESLTTRENCL11RECIPIENTIDCODE/NAME CQLBURN>TCQPIESLTTRENCL11INTERNAL:

ACRSAEOD/SPD/RRAB NRR/DE/ECGB NRR/DE/EMEB NRR/DRCH/HICB NRR/DRCH/HGMB NRR/DSSA/SPLR RES/DET/EIB AEJFILECEERLNRR/DRCH/HHFB NRR/DRCH/HOLB NRR/DRPM/PECB NRR/DSSA/SRXB RGN4FILE01111111,121111111EXTERNAL:

LSTLOBBYWARD11NOACPOORE>W.11NRCPDR11LITCOBRYCE>JHNOACGUEENER>DSNUDOCSFULLTXTNOTETOALL"RIDS"RECIPIENTS:

PLEASEHELPUSTOREDUCEWASTE!CONTACTTHEDOCUMENTCONTROLDESK,ROOMOWFN5D-5(EXT.

415-2083)

TOELIMINATE YOURNAMEFROMDISTRIBUTION LISTSFORDOCUMENTS YOUDON'TNEED!FUL'EXTCONVERSION REQUIREDTOTALNUMBEROFCOPIESREQUIRED:

LTTR25ENCL25 WASHINGTON PUBLICPOWERSUPPLYSYSTEMP.O.Box968~Richlanrl, 1Virshi>i@tow 99352-0968 July23,1997G02-97-147 DocketNo.50-397DocumentControlDeskU.S.NuclearRegulatory Commission Washington, D.C.20555Gentlemen:

Subject:

NUCLEARPLANTWNP-2,OPERATING LICENSENPF-21,LICENSEKEVIPWREPORTNO.97-007-00 Transmitted herewithisvoluntary LicenseeEventReportNo.97-007-00 forWNP-2.Thisreportissubmitted inresponsetotherecommendations contained inNUREG-1022.

Shouldyouhaveanyquestions ordesireadditional information regarding thismatter,pleasecallmeorMr.PaulInserraat(509)377-4147.

Respectfully, mlsViPresident, NuclearOperations MailDropPE23Enclosure cc:EWMerschoff, NRCRIVKEPerkins,Jr.,NRCRIV,WCFOTGColburn,NRRPDRobinson, Winston&StrawnNRCSr.ResidentInspector, MD927N(2)INPORecordsCenter-Atlanta,GADLWilliams, BPA,MD3999707300094 970723PDRADQCK05000397SPDRllllllllllllllllllllllllllllllllllllllll LICENSEEEVENTREPORT(LER)FACILITYNAME(1)WashintonNuclearPlant-Unit2DOCKETNUMBER(2)50-397PAGE(3)1OF3TITLE(4)VOLUNTARY REPORTOFAUTOMATIC STARTOFDG-1ANDDG-2DUETOSM-7ANDSM-8UNDERVOLTAGE EVENTDATE(5)LERNUMBER(6)REPORTDATE(7)OTHERFACILITIES INVOLVED(BlDAYSEOUENIIAL NUMBERREV.NUMBERDAYYEARFACILHYNAME0611979700072397FACILHYNAMEN/ADOCKETNUMBER05000OPERATING MODETHIsREpoRTIssUBMITTED pURsUANTToTHEREQUIRENENTs op10cpR5I(checkoneormore)(11)0%20A02(b)20A05(a)(1)(I) 20.405(a)(1)(ii) 20A05(a)(1)

(iii)20.405(a)(1)(iv) 20A05(a)(1)(v) 20A05(c)50.36(c)(1) 50.36(c)(2) 50.73(a)(2)0) 50.73(a)(2)(ii) 50.73(a)(2)(iii) 50.73(a)(2)

(iv)50.73(a)(2)(v) 50.73(a)(2)(vii) 50.73(a)(2)(viii)(A) 50.73(a)(2)(viii)(B) 50.73(a)(2)(x)

X73.71(b)73.71(c)OTHERVoluntary NAMEBillPfitzer,Licensing EngineerLICENSEECONTACTFORTHISLER(12)TELEPHONE NUMBER((ncludeAreaCode)509-377-2419 COMPLETEONELINEFOREACHCOMPONENT FAILUREDESCRIBED INTHISREPORT(13)CAUSECOMPONENT MPIAIFACTURER REPORTABLE TONPRDSCAUSESYSTEMCOMPONENT MANUFACTURER REPORTABLE TONPRDSSUPPLEMENTAL REPORTEXPECTED(14)YEScornle(edEXPECTEDSUBMISSION DATENOEXPECTEDMONTHDAYABSTRACTOn6/11/97,withtheplantinOperating Mode4,Circulating WaterPumpmotorCW-M-P/1C experienced internalelectrical faultingshortlyafterpumpstartup.Thepumpranforapproximately 15secondspriortotrippingtheCW-M-P/1C feederbreaker.due tophasedifferential current.Themotorfaultcausedamomentary undervoltage condition onelectrical bussesSM-7andSM-8whichinitiated anautomatic startofemergency dieselgenerators, EDG-1andEDG-2.Thedieselgenerators startedandranunloaded, asdesigned, untilmanuallyshutdownbyoperating personnel.

TheoutputbreakersforEDG-1andEDG-2didnotcloseandloadtheEDGsbecausetheundervoltage condition wasonlymomentary, andplantbussescontinued tobefedfromthestartuptransformer, TR-S.Immediate corrective actionsweretoreturnEDG-1andEDG-2tostandbyreadiness andinitiateaninvestigation intothecauseofCW-M-P/1C trip.TherootcauseofEDG-1andEDG-2autostartwasanundervoltage condition onelectrical bussesSM-7andSM-8Thiseventisvoluntarily

reported, Thesafetysignificance ofthiseventisconsidered minimal.

FACILITYNAME(I)LICENSEEEVENTREPORT(LER)TEXTCONT(NUATION DOCKETNUMBER(2)YEARLERNUMBER(6)SEQUENTiALNUMBERRCVI61ONNJNB6RPAGE(3)Washington NuclearPlant-Unit250-39797007002OF3TEXT(IfmorespaceIsreqU(red, useadditional copiesofNRCForm366A)(17)EvenDecritinOn6/11/97,withtheplantinOperating Mode4withelectrical distribution beingsuppliedbythestartuptransformer TR-S[XFMR],Circulating WaterPumpmotorCW-M-P/1C

[KE][P][MO]

experienced internalelectrical faultingshortlyafterpumpstartup.Thepumpranforapproximately 15secondspriortotrippingtheCW-M-P/1C feederbreaker[BKR]duetophasedifferential current.Themotorfaultcausedamomentary undervoltage condition onelectrical bussesSM-7andSM-8[BU]whichinitiated anautomatic startofemergency dieselgenerators, EDG-1andEDG-2[DGJ.Thedieselgenerators startedandranunloaded, asdesigned, untilmanuallyshutdownbyoperating personnel.

TheoutputbreakersforEDG-1andEDG-2didnotcloseandloadtheEDGsbecausetheundervoltage condition wasonlymomentary, andplantbusescontinued tobefedfromthestartuptransformer, TR-S.Thiseventwasvoluntarily reportedwithin4hours,andthisreportisbeingvoluntarily submitted sincetheEDGsarenotengineered safetyfeaturesatWNP-2.Immediate orriveActinCirculating WaterpumpCW-P-1Ccontrolswitchwasplacedinpull-to-lock.

EDG-1andEDG-2werereturnedtostandbyreadiness.

Investigation wasinitiated intothecauseofCW-M-P/1C trip.Asignificant ProblemEvaluation Requestwasinitiated toresolvethisproblem.hControlroompersonnel reportedthatCW-M-P/1C startednormallywiththeexpectedstartingcurrent,andoperatedwitharunningcurrentofapproximately 600ampsforapproximately 15secondspriortotripping.

Following thetrip,phasevoltagesonthebussupplying themotorwereobservedtobe4250,4400,and4300voltsoneachoftheA,B,andCphasesrespectively withthe230kVvoltageatAshesubstation reportedat242kV.Throughout thisevent,plantbussescontinued tobefedfromthestartuptransformer, TR-S.TheWNP-2electrical distribution systemrelayschemeoperatedasdesignedtoisolatethefaultandterminate theundervoltage condition ontheaffectedbusses.Hadtheundervoltage condition onSM-7andSM-8continued forapproximately fourseconds,thesupplybreakersfromBackupAuxiliary Transformer, TR-B,wouldhaveautoclosedandSM-7andSM-8wouldhavebeensuppliedbyTR-B.Iftheundervoltage condition hadcontinued forapproximately 7secondstheEDGoutputbreakerswouldhaveautoclosedandSM-7andSM-8wouldhavebeensuppliedbytheEDGs.

0~LICENSEEEVENTREPORT(LER)TEXTCONTINUATION FACILITYNAMEtl)DOCKETNUMBER)2)LERNUMBERI6)SEQUENT)AL NUMBERA6V)ATIONNAQERPAGEI3)Washington NuclearPlant-Unit250-39797007003'F3TEXT(lfmorespaceisrequired, useadditional copiesofNRCForm366A)(17)InthiscasethefeederbreakerforCW-M-P/IC tripped,isolating thefaultimmediately, andthestandbysourcesdesignedtoautomatically supplythesafety-related electrical busseswerenotneeded.mRafXameTheautostartofEDG-1andEDG-2wascausedbyanundervoltage condition onSM-7andSM-8.Theundervoltage condition wascausedbyinternalfaultingofthenon-safety relatedCW-M-P/1C whichdeveloped shortlyafterstartofthemotor.FherorrtiveAcinNonerequired.

EDGresponsetotheundervoltage condition wasnormal.Appropriate corrective actionsassociated withCW-P-P/IC havebeentaken.AemnffetnuenceWNP-2'selectrical distribution systemrelayschemeoperatedasdesignedtoisolatethefaultwithoutunnecessary challenges totheplantelectrical distribution system.InthiscasethefeederbreakerforCW-M-P/IC tripped,isolating thefaultimmediately.

Offsiteandonsitesourcesdesignedtoautomatically supplythesafety-related electrical busseswereavailable atthetimefromtransformer TR-8andtheEDGs.Thesafetysignificance ofthiseventisconsidered minimal.ETherehavebeennosimilarpreviouseventsofmotorfaultscausingstartsoftheEDGs.