ML17228A589

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Special Rept:On 940504,non-valid Failure of EDG 1A Occurred Due to Spurious Actuation of High Water Jacket Temp Switch (Designated TS-59-003A).Subj Switch Replaced W/New Model 9025G & EDG 1A Declared Back in Svc on 940505
ML17228A589
Person / Time
Site: Saint Lucie NextEra Energy icon.png
Issue date: 06/02/1994
From: SAGER D A
FLORIDA POWER & LIGHT CO.
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
L-94-136, NUDOCS 9406130069
Download: ML17228A589 (4)


Text

ACCELERATE DOCUMENTDISTRI@3TION SYSTEMREGULATORY INFORMATION DISTRXBUTION SYSTEM(RIDS)ACCESSION NBR:9406130069 DOC.DATE:

94/06/02,NOTARIZED:

NOFACIL:50-335 St.LuciePlant,Unit1,FloridaPower&LightCo.AUTH.NAMEAUTHORAFFILIATION SAGER,D.A.

FloridaPower&LightCo.RECIP.NAME RECIPIENT AFFILIATION DocumentControlBranch(Document ControlDesk)

SUBJECT:

Specialrept:on940504,non-valid failureofEDG1Aoccurredduetospuriousactuation ofhighwaterjackettempswitch(designated TS-59-003A).Subj swatchreplacedw/newmodel9025G&EDG1Adeclaredbackinsvcon940505.DISTRIBUTION CODE:IE22DCOPIESRECEIVED:LTR fENCLSIZE:TITLE:50.73/50.9 LicenseeEventReport(LER),&nciden Rpt,etc.NOTES:DOCKET05000335DRECIPIENT IDCODE/NAME PD2-2PDINTERNAL:

ACRSAEOD/ROAB/DS PNRR/DE/EMEB NRR/DRCH/HHFB NRR/DRCH/HOLB NRR/DSSA/SPLB NRR/PMAS/IRCB-E RES/DSIR/EXB EXTERNAL:

EG&GBRYCE,J.H NRCPDRNSXCPOORE,W.COPIESLTTRENCL111122111111111111221111RECXPXENT IDCODE/NAME NORRIS,JAEOD/DSP/TPAB NRR/DE/EELB NRR/DORS/OEAB NRR/DRCH/HICB NRR/DRSS/PRPB NRRDSSA/SRXB EG~302GN2FILE01LSTLOBBYWARDNSICMURPHYiG~ANUDOCSFULLTXTCOPXESLTTRENCL111111111122111111111111DDDNOTETOALL"RIDS"RECIPIENTS:

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

TOELIMINATE YOURNAMEFROMDISTRIBUTION LISTSFORDOCUMENTS YOUDON'TNEEDITOTALNUMBEROFCOPIESREQUIRED:

LTTR27ENCL27D FPLZune2,1994L-94-13610CFR50.36U.S.NuclearRegulatory Ccmnission Attn:DocumentControlDeskWashington, D.C.20555Re:St.LucieUnit1DocketNo.50-335SpecialReportDateofEvent:'May4,1994TheattachedSpecialReportisbeingsubmitted pursuanttotherequirements ofSt.LucreTechnical Specifications.

'hisreportprovidesnotification ofonenon-valid failureofthe1ADieselGenerator.

Shouldtherebeanyquestiononthisinformation, pleasecontactus.Verytrulyyours,D.A.gerVicersidentSt.u'ePlantDAS/JNH/kw Attachment cc:StewartD.Ebneter,RegionalAdministrator, USNRCRegionIISeniorResidentInspector, USNRC,St.LuciePlantDAS/PSLN1132-94940613006'P

'rr40602PDRADOCK050003358PDRanFPLGroupcompany NRCSPECIALREPORTDIEELGENERATRNON-VALID FAILURESPECIALREPORTI.TITLE1AEmergency DieselGenerator non-valid failureduetoaspuriousactuation ofahighwaterjackettemperature switch.II.INITIALCONDITIONS St.LucieUnit1andUnit2wereat100%power.III.EVENTSEQUENCEOn5/4/94,the1AEmergency DieselGenerator (EDG)wasstartedtoperformasurveillance inaccordance withTechnical Specifications Table4.8-1.Surveillance testingofthe1AEDGisrequiredevery31days.The1AEDGsurveillance beganat1228.The1AEDGautomatically trippedat1305onhighwaterjackettemperature.

Anoperatorwasrecording theEDGparameters atthetimeofthetripandthewatertemperatures werebelowthe205degreesFahrenheit designtripsetpointofthetemperature switch(designated TS-59-003A).

Thetemperature switchwasreplaced, thesurveillance wassuccessfully performed andthe1AEDGwasdeclaredbackinserviceat0245on5/5/94.The1AEDGwasoutofserviceforapproximately 14hourstoreplacethetemperature switch.IV.CAUSEOFTHEEVENTThe1AEDGtrippedduetoanon-valid waterjackethightemperature causedbyasetpointdriftofthetemperature switch.Atthetimeofthetriptherecordedwatertemperature was172degreesFahrenheit asreadfrominstalled thermometers inthewaterpiping(theaccuracyofthethermometers wasverified).

NRCSPECIALREPORTDIEELENERATORNON-VALID FAILURESPECIALREPORTV.CORRECTIVE ACTIONS1)TS-59-003A (model9025B)wasreplacedwiththenewmodel9025Gtemperature switch.Thetemperature switchmanufacturer (SquareD)hasreplacedthemodel9025Bswitchwiththe9025Gswitchbecauseitislesssusceptible tosetpointdriftandrepeatability problems.

2)The1AEmergency DieselGenerator wasdedaredbackinserviceat0245on5/5/94following thesuccessful completion ofthesurveillance run.3)TheInstrumentation andControlDepartment performed adetailedinspection androotcauseanalysisonthetemperature switch.4)NuclearPlantWorkOrders(NPWO's)havebeengenerated toreplacetemperature switchesofthismodelnumber(9025B).Vl.SUPPORTING INFORMATION

-Thisproblemwasevaluated tobeanon-valid failureperReg.Guide1.108C.2.e.2becausethehighwaterjackettemperature shutdownisoverridden duringthepresenceofaSafetyInjection Actuation Signalandanundervoltage condition onthesafetyrelated4.16KVACbuses.Additionally, actualwaterjackettemperature neverexceeded172degreesFahrenheit.

Thus,theunsuccessful runwasattributed tothespuriousoperation ofatripthatisbypassedintheemergency operating mode.-The1AEDGwasoutofserviceforapproximately 14hoursuntiltheswitchreplacement couldbecompleted andasuccessful surveillance testperformed

-Thesurveillance schedulerequiredbecauseofthisnon-valid failureremainsat31days.Thelastvalidfailureofthe1AEDGwason7/5/91andremainsthesinglevalidfailuresince6/12/90(EDGruncountsstartedatthistimewhenReg.Guide1.108wasimplemented intotheSt.LucieUnit1Technical Specifications).

Thecurrentnumberofvalidtestsforthe1AEDGisnow56.