ML17229A616

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LER 98-001-00:on 980104,inadvertent RPS Actuation Occurred Due to Personnel Error.Caused by Procedural Inadequacies & Inadequate self-checking by Licensed Utility Personnel. Placards Have Been Placed in CRs.W/980203 Ltr
ML17229A616
Person / Time
Site: Saint Lucie NextEra Energy icon.png
Issue date: 02/03/1998
From: FREHAFER K W, STALL J A
FLORIDA POWER & LIGHT CO.
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
L-98-018, L-98-18, LER-98-001, LER-98-1, NUDOCS 9802110012
Download: ML17229A616 (7)


Text

CATEGORY1~REGULARLY INFORMATION DISTRIBUTIOF%YSTEM (RIDS)p)*ACCESSION NBR:9802110012 DOC.DATE:

98/02/03NOTARIZED:

NOFACIL:50-335 St.LuciePlant,Unit1,FloridaPower&LightCo.AUTH.NAMEAUTHORAFFILIATION FREiIXFER,K.W.

FloridaPower&LightCo.-STALL,J.A.

FloridaPower&LightCo.RECIP.NAME RECIPIENT AFFILIATION DOCKET¹05000335

SUBJECT:

LER98-001-00:on 980104,inadvertent RPSactuation occurredduetopersonnel error.Causedbyprocedural inadequacies

&,inadequate self-checking by.licensedutilitypersonnel.

PlacardshavebeenplacedinCRs.W/980203 ltr.DISTRIBUTION CODE:IE22TCOPIESRECEIVED:LTR ENCLSIZE:TITLE:50.73/50.9 LicenseeEventReport(LER),IncidentRpt,etc.NOTES:'CRECIPIENT IDCODE/NAME PD2-3PDINTERNAL:

ACRSAEOD/SPD/RRABNRR/DE/ECGB NRR/DE/EMEB NRR/DRCH/HICB NRR/DRCH/HQMB NRR/DSSA/SPLB RES/DET/EIB EXTERNAL:

LSTLOBBYWARDNOACPOORE,W.NRCPDRCOPIESLTTRENCL111111111111111111111111RECIPIENT IDCODE/NAME WIENS,L.CgNRRDEEELBNRR/DRCH/HHFB NRR/DRCH/HOLB NRR/DRPM/PECB NRR/DSSA/SRXB RGN2FILEOlLITCOBRYCE,JHNOACQUEENER,DS NUDOCSFULLTXTCOPIESLTTRENCL112211111111111111111111NOTETOALL"RIDS"RECIPIENTS:

PLEASEHELPUSTOREDUCEWASTE.TOHAVEYOURNAMEORORGANIZATION REMOVEDFROMDISTRIBUTION LIST>>ORREDUCETHENUMBEROFCOPIESRECEIVEDBYYOUORYOURORGANIZATION, CONTACTTHEDOCUMENTCONTROIDESK(DCD)ONEXTENSION 415-2083FULLTEXTCONVERSION REQUIREDTOTALNUMBEROFCOPIESREQUIRED:

LTTR25ENCL25 FloridaPower&LightCompany,6351S.OceanDrive,JensenBeach,FL34957February3,1998L-98-01810CFR50.73U.S.NuclearRegulatory Commission Attn:DocumentControlDeskWashington, D.C.20555Re:St.LucieUnit1DocketNo.50-335Reportable Event:98-001DateofEvent:January4,1998Inadvertent RPSActuation DuetoPersonnel ErrorTheattachedLicenseeEventReportisbeingsubmitted pursuanttotherequirements of10CFR50.73.Verytrulyyours,J.A.StallVicePresident St.LuciePlantJAS/KWFAttachment cc:RegionalAdministrator, USNRC,RegionIISeniorResidentInspector, USNRC,St.LuciePlant'ir802ii0012

'rr80203PDRADQCK050003358PDRllllllllllllllllllllllllll llllllllllll anFPLGroupcompany NRCFORM366(4.9e)U.S.NUCLEARREGULATORY COMMISSION LICENSEEEVENTREPORT(LER)(Seereverseforrequirednumberofdigits/characters foreachbiock)APPROVEDSVOMBNo.S(60<0(O4 EXARES04/30/SSESTIMATED BURDENPERRESPONSETOCOMPLYWITHTHISMANDATORINFORMATION COLLECTION REOUEST:60.0HRS.REPORTEDLESSONLEARNEDAREINCORPORATED INTOTHEUCENSINGPROCESSANDFEBACKTOINDUSTRY.

FORWARDCOMMENTSREGARDING BURDENESTIMATTOTHEINFORMATION ANDRECORDSMANAGEMENT BRANCH(TWF33(US.NUCLEARREGIAATORY COMMISSION, WASHINGTON, DC20666ENOIANDTOTHEPAPERWORK REDUCTION PROJECT(3(600104I, OFRCE0MANAGEMENT ANDBUDGET,WASHINGTON, DC20603.FACIUTYNAMEUISTLUCIEUNIT1TITLE(4IInadvertent RPSActuation DuetoPersonnel ErrorDOCKETNINVIB(R(2(05000335PAGE(SI1OF4DAYYEAR498YEARSEOUENTIAL REVISIONMONTHNUMBERNUMBER98,-001-0OAYYEAR398FACIUTYNAMEFACIUTYNAMEDOCKETNUMBER05000DOCKETNUMBER 05000OPERATINQ MODE(9)POWERLEVELl10)20.2201(b)20.2203(a)(2)6)20.2203{a)

(2)(iii)20.2203(a)(2)(iv)20.2203(a) l2)(v)20.2203(a)

(3)(ii)50.36(c)(1)50.36(c)(2)50.73(a)l2){i)50.73(a)(2)(iii)50.73(a){2){v)50.73(a)(2)(vii) 50.73{0)l2)(viii)73.71OTHERSpecifyInAbstractbeloworinNRCForm366ANAMEK.W.Frehafer, Licensing EngineerTELEPHONE NUMBERSrc(vdeArtaCodel(561)468-4284CAUSESYSTEMCOMPONENT MANUFACTURER REPORTABLE TONPRDSCAUSESYSTEMCOMPONENT MANUFACTURER ToNPRDSJCN/AN/AN/AYES{Ityes,completeEXPECTEDSUBMISSION DATE).XNoEXPECTEDSUBMISSION DATE(15)MONTHOAYYEARABSTRACT(Umitto1400spaces,l.e.,approximately 15single-spaced tYpewritten lines)(16)OnJanuary4,1998,Unit1wasatzeropercentpower,inMode3,withpressurizer pressurelessthan1750psig.Areactorplantheatuptonormaloperating temperature andpressurefollowing refueling wasinprogress.

Thereactortripbreakerswereclosedandallreactorcontrolelementassemblies werefullyinserted.

Theoperators weredirectedtoremovethezeropowermodebypasskeysforeachchannelofthereactorprotection systemoncethefourthreactorcoolantpumpwasstarted.Thereactortripbreakersopenedimmediately afterthereactorprotection system'C'hannel zeropowermodebypasswasunbypassed.

Thiseventwascausedbyprocedural inadequacies andinadequate self-checking bylicensedutilitypersonnel.

Theprocedure didnotaddressplantconditions necessary toensurethereactorprotection systemthermalmarginflow pressuretripsetpointwasbelowactualsystempressurewhenthezeropowermodebypasskeyswereoperated.

Duringtheevent,plantconditions wouldhavesetthethermalmargin/low pressuretripsetpointat1887psia,andactualreactorcoolantsystempressurewasapproximately 1740psiawhenthereactorprotection systemzeropowermodebypasswasunbypassed.

Additionally, theoperatorcontinued withtheunbypassing ofthezeropowermodebypassanddidnotgivethecrewtimetoreviewthevalidityofthealarmsandensureallconditions weresatisfactory priortocompleting theprocedure.

Corrective actionsincludedprocedural enhancements, counseling theoperator, andcrewbriefings ontheevent.NRCFORM366{4.9S)

NRCFORM366AI4.9S)LICENSEEEVENTREPORT(LER)TEXTCONTINUATION U.S.NUCLEARREGULATORY COMMISSIO ST.LUCIEUNIT105000335YEARSEQUENTIAL REVISION98-001-02OF4TEXT/ifmorespeceisrequired, useeddidonel copiesofNRCForm36@A/I17]OnJanuary4,1998,Unit1wasatzeropercentpower,inMode3,withpressurizer pressurelessthan1750psig.Areactorplantheatuptonormaloperating temperature andpressurefollowing refueling wasinprogressinaccordance withNormalOperating Procedure NOP-1-0030121, "ReactorPlantHeatup-ColdtoHotStandby."

ReactorCoolantSystem(RCS)temperature wasapproximately 510'Fandpressurewasapproximately 1700psia.ReactorTripCircuitBreakers(TCBs)[EIIS:JC:BKR]

wereclosedandallreactorControlElementAssemblies (CEAs)[EIIS:AA]

werefullyinserted.

ThefourthReactorCoolantPump(RCP)[EIIS:AB:P],

1A1,wassuccessfully startedinaccordance withstep6.5.12oftheheatupprocedure.

Step6.5.13directsanoperatortoremovetheZeroPowerModeBypass(ZPMB)[EIIS:JC:33]

keysforeachchanneloftheReactorProtection System(RPS)[EIIS:JC]

oncethefourthRCPisstarted.At1050,thereactoroperatorturnedtheZPMBkeyfrombypasstooffforRPSchannel'A'ndtheThermalMargin/Low Pressure(TM/LP)triplockedin.Thereactoroperatorcontinued

,withtheprocedure andturnedtheZPMBkeyfrombypasstooffforRPSchannels'B','C',and'D'nsequence.

ItwasthennotedthattheTCBshadopened,anditwasconfirmed viatheSequenceofEventsRecorder(SOER)[EIIS:IQ]

thattheTCBshadopenedimmediately afterRPSchannel'C'asunbypassed.

Theoperators immediately returnedtheZPMBkeysbacktothebypassposition.

Thiseventwascausedbyprocedural inadequacies inprocedure NOP1-0030121, "ReactorPlantHeatup-ColdtoHotStandby."

Inadequate self-checking bylicensedutilitypersonnel contributed tothisevent.Procedure NOP1-0030121, "ReactorPlantHeatup-ColdtoHotStandby,"

step6.5.13,directstheoperators toplacetheZPMBkeyfrombypasstooffafterthefourthRCPisstarted.However,theprocedure didnotaddressalltripfunctions potentially bypassedbytheZPMBkey.TheZPMBswitchisakeyoperatedswitch,oneforeachRPSchannel.TheZPMBallowstheRPSlowflowandTM/LPtripstobebypassedforsubcritical testingofcontrolelementdrivemechanisms; ThisRPSbypassisautomatically removedwhenreactorpowerlevelincreases aboveonepercentpower.ThelowflowtripisprovidedtoprotectthecoreagainstDeparture fromNucleateBoiling(DNB)intheeventofacoolantflowdecrease.

Thelowflowtripisafunctionofmeasureddifferential.

pressureacrossthesteamgenerators andthenumberofoperating RCPs.NRCFORM366A(4-9S) y1 NRCFORM366AI4.96)LICENSEEEVENTREPORT(LER)TEXTCONTINUATION U.S.NUCLEARREGULATORY COMMISSIO ST.LUCIEUNIT105000335YEARSEQUENTIAL REVISION98-001-03OF4TEXTllfmorespeceisrequired, useedditionel copiesoffVRCForm3MAII17ICAUSEOFTHEEVENTcont'dTheTIVI/LPtripisprovidedfortwopurposes.

Thelowpressurizer pressureportionofthetripfunctions totripthereactorintheeventofalossofcoolantaccident.

Thethermalmarginportionofthetrip,inconjunction.

withthelowreactorcoolantflowtrip,isdesignedtopreventthereactorcoresafetylimitonDNBfrombeingviolatedduringanticipated operational occurrences.

TheTM/LPtripsetpointiseitheracalculated pressurevaluebasedonRCStemperature, powerandflow,oraminimumbiasedpressurevalueof1887psia.Duringtheevent,fourRCPswereoperating (ensuring thatalowflowtripwouldnotbepresent),

butexistingplantconditions settheTM/LPtripsetpointattheminimumbiasedpressurevalueof1887psia,TheZPMBkeyswereplacedfrombypasstooffwhileRCSpressurewasapproximately 1740psia,whichresultedintheTM/LPtripandopeningthereactorTCBs.Additionally, personnel errorbytheoperatorandoperating crewresultedinnotinvestigating thecauseoftheTM/LPalarmswhentheywerereceivedastheRPSchannelZPMBkeysweresequentially placedfrombypasstooff.Theoperatorcontinued withtheprocedure anddidnotgivethecrewtimetoreviewthevalidityofthealarmsandensureallconditions weresatisfactory priortocompleting theprocedure.

TheTCBsopenedwhenthethirdRPSchannelZPMBkeywasplacedfrombypasstooff,whichcompleted thecoincidence requirements fortheTM/LPreactortrip.St.LuciePlantmanagement expectations forlicensedoperatorresponsetounexpected controlroomalarmsarethatthelicensedoperatoracknowledging thealarmannouncethealarmtocontrolroompersonnel as"unexpected,"

thatcontrolroomactivities stoptopermitinvestigation ofthealarm,andthatactionsaretakeninaccordance withplantalarmresponseprocedures todetermine thecauseofthealarm.Suchactivities didnotoccurduringthisevent.Thiseventisreportable asavalidactuation oftheRPSper10CFR50.73(a)(2)(iv).

SinceremovingthebypassfromtheZPMBrestoredthecapability oftheTM/LPtripcircuitry torespondtoanRCSlowpressurecondition, thiseventisconsidered avalidRPSactuation basedonactualplantconditions.

ItwasreportedtotheNRCasafourhourENSnotification at1708hoursonJanuary5,1998.ThereactorwasshutdowninHotStandbypriortotheevent.AlthoughtheTCBswereopenedbyavalidRPSsignal,thereactortripsignaldidnotresultinanyphysicalchangetocorereactivity becausetheCEAswerefullyinsertedpriortothetripsignal.Therefore, thiseventhadnoimpacttothehealthandsafetyofthepublic.NRCFOAM388AI4.96)

NRCFORM366AI4-9SILICENSEEEVENTREPORT(LER)TEXTCONTINUATION U.S.NUCLEARREGULATORY COMMISSIO ST.LUCIEUNIT105000335YEARSEQUENTIAL REVISION98-001-04OF4TEXT(Ifmorespeceisrequired, useeddilionel copiesofftVRCRearm366AjI17)2.Procedure changestoNOP1-0030121 andNOP2-0030121, "ReactorPlantHeatup-ColdtoHotStandby,"

wereinitiated toensurethatafterthefourthRCPisstarted,theZPMBbypasskeysremaininbypassuntilpressureisgreaterthan1900psiaandnotripsarepresent.iTheoperatorwascounseled, andtheoperatorconducted briefings foreachoperating crewtodescribetheeventindetail,including theseriousness oftheevent,theuseofselfchecking, andtheneedforinvolvement fromtheoperating crewwhenalarmsarereceived.

3.Placardshavebeenplacedinthecontrolroomsthatrequireeitherofthefollowing conditions bemetpriortoplacingtheZPMBkeysfrombypasstooff:a)thereactorTCBSopen,orb)theunitatnormaloperating temperature andpressure.

NoneNoneNRCFORM386AI4.95)