ML17229A397

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LER 97-004-00:on 970611,discovered Incorrect Original Cable Tray Fire Stop Assembly Installation Was Outside App R Design Basis.Caused by Personnel Error.Hourly Fire Watch Patrols Will Be posted.W/970711 Ltr
ML17229A397
Person / Time
Site: Saint Lucie NextEra Energy icon.png
Issue date: 07/11/1997
From: FREHAFER K W, STALL J A
FLORIDA POWER & LIGHT CO.
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
L-97-179, LER-97-004-02, LER-97-4-2, NUDOCS 9707150008
Download: ML17229A397 (7)


Text

('A.'l'EQO8.2REGULATIO INFQRMATIQN DIBTRIBUTIor~sTEM (RIDE)!ACCESSION NBR:9707150008 DOC.DATE:

97/07/11NOTARIZED:

NOFACIL'.50-389 St.LuciePlant,Unit2,FloridaPower&LightCo.AUTH.NAMEAUTHORAFFILIATION FREHA:ER,K.W.

FloridaPower&LightCo.STALL,J.A.

FloridaPower6LightCo.RECIP.NAME RECIPIENT AFFILIATION DOCKET¹05000389

SUBJECT:

LER97-004-00:on 970611,discovered incorrect originalcabletrayfirestopassemblyinstallation outsideAppRdesignbasis.Causedpersonnel error.Postedhourlyfirewatchpatrols.W/970711 ltr.DISTRIBUTION CODE:IE22TCOPIESRECEIVED:LTR

'NCLSIZE:TITLE:50.73/50.9 LicenseeEventReport(LER),IncidentRpt,etc.NOTES:RECIPIENT IDCODE/NAME PD2-3PDINTERNAL:

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

LSTLOBBYWARDNOACPOOREFW.NRCPDRCOPIESLTTRENCL111111111111111111111111RECIPIENT IDCODE/NAME WIENSFL~AEOD/SPD/RAB ET~KRONENRR/DRCH/HHFB NRR/DRCH/HOLB NRR/DRPM/PECB NRR/DSSA/SRXB RGN2FILE01LITCOBRYCE,JHNOACQUEENERFDS NUDOCSFULLTXTCOPIESLTTR'ENCL112211111111111111111111NOTETOALL"RIDS"RECIPIENTS:

PLEASEHELPUSTOREDUCEWASTEICONTACTTHEDOCUMENTCONTROLDESK,ROOMOWFNSD"5(EXT.

415-2083)

TOELIMINATE YOURNAMEFROMDISTRIBUTION LISTSFORDOCUMENTS YOUDONTNEEDrFULLTEXTCONVERSION REQUIREDTOTALNUMBEROFCOPIESREQJIRED:

LTTR25ENCL25 FloridaPower&LightCompany,6501SouthOceanDrive,JensenBeach,FL34957July11,1997L-97-17910CFR50.73U.S.NuclearRegulatory Commission Attn:DocumentControlDeskWashington, D.C.20555Re:St.LucieUnit2DocketNo.50-389Reportable Event:97-004DateofEvent:June11,1997Incorrect OriginalCableTrayFireStopP~TheattachedLicenseeEventReportisbeingsubmitted pursuanttotherequirement's of10CFR50.73toprovidenotification ofthesubjectevent.Verytrulyyours,J.A.StallVicePresident St.LuciePlantJAS/KWFAttachment l/(W)cc:RegionalAdministrator, USNRCRegionIISeniorResidentInspector, USNRC,St.LuciePlant'Ir707150008 9707iXPDRADOCK0500038'P SPDRanFPLGroupcompanyiliillllllllllllllllllllllllIlls lllllll NRCFORM366(4.95)U.S.NUCLEARREGULATORY COMMISSION LZCENSEEEVENTREPORT(LER)(Seereverseforrequirednumberofdigits/characters foreachblock)APPROVEDSYOMSNo.3160%I04Exp)RES04)3ore6ESTIMATED BURDENPERRESPONSEToCOMPLYWITHTHISMANDATOINFORMATION COLLECTION REGUEST:60.0HRS.REPORTEDLESSONLEARNEDAREINCORPORATED INTOTHEUCENSINGPROCESSANDFEBACKTOINDUSTRY.

FORWARDCOMMENTSREGARDING BURDENESTIMATToTHEINFORMATION ANDRECORDSMANAGEMENT BRANCHIT%F33)U.S.NUCLEARREGIAATORY COMMISSION.

WASHINGTON, OC206664KO)

ANDTOTHEPAPERWORK REDUCTION PROJECTI3160<104),

OFFICE0MANAGEMENT ANDBUDGET,WASHINGTON, DC20603.FACIUTYNAME(1)STLUCIEUNIT2DOCKETNUMBER12)05000389PAGE13I1OF4TITLEI4)Incorrect OriginalCableTrayFireStopAssemblyInstallation OutsideAppendixRDesignBasesMONTHDAYYEAR1197SEQUENTIAL REVISIONNUMBERNUMBER97-004-0MONTHDAYYEAR97FACIUTYNAMEFACILITYNAMEDOCKETNUMBER05000DOCKETNUMBER 05000OPERATING MQDE(9)POWERLEVEL(10)10020.2201(b) 20.2203(a)(2)

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

(3)(n)50.36(c)(1)50.36(c)(2)50.73(a)(2)(1) 50.73(a)(2)

(iii)50.73(a)(2)

(v)50.73(a)(2)(vii)50.73(a)(2)(viii)73.71OTHERSpecifyinAbstractbeloworinNRCForm3BSANAMEK.W.Frehafer, Licensing EngineerTELEPHONE NUMBERSecludeAreeCode)(5611468-4284CAUSESYSTEMCOMPONENT MANUFACTURER REPORTABLE TONPRDS,x:,t,;4(..NkÃ"'9):A cAusEsYsTEMcoMpoNENT MANUFACTURER REPORTABLE ToNPRDSYEs(Ifyes,completeEXPECTEDSUBMISSION DATE).XNoEXPECTEDSUBMISSION DATE(15)MONTHOAYYEARABSTRACT(Limitto1400spaces,i.e.,approximately 15single-spaced typewritten lines)(16)OnJune11,1997,St,LucieUnit2wasinMode1at100percentpower.Inspection resultsindicated that,generically, twosidedcabletrayfirestopassemblies lackedtheinstallation ofceramicfiberbetweencableswithinthefirebarrier.FPLdetermined thattheas-builtconfiguration oftwosidedcabletrayfirestopassemblies didnotmeetthetestedconfiguration forathreehourfireratedassembly.

AlltheSt.LucieUnit2twosidedcabletrayfirestopassemblies weredeclaredinoperable.

Theapparentcauseofthiseventwasduetopersonnel errorduringtheimplementation ofdesigndrawingsorinsufficient designguidanceduringinitialinstallation.

Corrective actionsincludethepostingofhourlyfirewatchpatrolsthatwereestablished tocompensate fortheinoperable firestopassemblies.

Repairsorplantmodifications willbeimplemented torestoretheaffectedfirestopassemblies totheirrequiredthreehourfirerating.NACFOAM366(4.95)

NRCFORM366AI4-9SILICENSEEEVENTREPORT(LER)TfXTCONTINUATION U.S.NUCLEARREGULATORY COMMISSIO STLUCIEUNIT205000389YEARSEQUENTIAL REVISION97-004-02OF4TEXTIlfmorespaceisrequired, useadditional copiesofiVRCForm366Ai(17lOnJune11,1997,St.LucieUnit2wasinMode1at100percentpower.FPLwasinvestigating discrepancies oftwosidedcabletrayfirestopassemblies identified duringpreviousfieldsurveillances.

Intrusive inspections oftheremaining population offirestopassemblies ofthisdesignwereinprogresstodetermine theextentoftheissue.Preliminary inspection resultsindicated that,generically, theas-builtconfiguration oftwosidedcabletrayfirestopassemblies lackedtheinstallation ofceramicfiberbetweencableswithinthefirebarrier.Theconfiguration didnotconformtothedesigndrawingsandFPLascertained thattheidentified fieldconditions werenotpreviously evaluated duringinitialconstruction.

Therefore, thetwosidedcabletrayfirestopassemblies didnotmeetthetestedconfiguration forathreehourfireratedassembly, asrequiredbytheplant10CFR50AppendixRcommitments.

Asaconservative measure,alltheSt.LucieUnit2twosidedcabletrayfirestopassemblies weredeclaredinoperable basedonthepreliminary inspection results.Hourlyfirewatchpatrolswereestablished ascompensatory measuresasrequiredbyplantadministrative procedures.

St.LucieUnit1doesnotutilizecabletrayfirestopsofthisdesign,sothiscondition isonlyapplicable toUnit2.Areviewoftheoriginalinstallation andinspection documentation fortheconstruction ofthetwosidedcabletrayfirestopassemblies suggeststhattheapparentcauseofthiseventwasduetopersonnel errorduringtheimplementation ofdesigndrawingsorinsufficient designguidanceduringinitialinstallation.

Acontributing causewasthattheinstallation drawingswerenotclearinspecifying thatceramicfiberneededtobeinstalled aroundeachcableinthefirestopassembly.

Thiscondition wasdiscovered duringarecentfirestopsurveillance.

Consistent withtheIndustry, normalfirebarrierinspection criterion isavisualinspection ofexposedsurfacescheckingforvoids,gaps,andholes.Nointrusive inspections ordisassembling offirebarriersareperformed.

Oneofthefirestopswaslocatedsuchthatavisualinspection wasdifficult toperform,sotheinspector ranhishandaroundthefirestoptocheckforvoids,gaps,'andholes.Theinspector notedairflowbetweencablesthroughtheassembly.

Althoughairflowwasnotedduringthatinspection, routinedetection ofairflowthroughadiscrepant firestopisproblematic innatureandhighlydependent ontheexistence ofadifferential pressureacrossthefirebarrier.Evenifpreviousinspections wereperformed inahandsonmanner,adifferential pressurecouldnotbeassuredbecauseofReactorAuxiliary Buildingventilation lineupordoorconfigurations ineffectduringtheinspection.

Thiscondition isreportable under10CFR50.73(a)(2)(ii)(B) becausetheasfoundcondition oftheUnit2twosidedcabletrayfirestopassemblies donotmeetthreehourfirebarrierrequirements.

Thefirebarriersarediscussed intheUnit2.UFSARinchapter9.5A.Theprincipal designobjective ofthefirebarrierandassociated penetration sealsistoprotectpersonnel andredundant equipment fromtheeffectsofpostulated firesinthereactorauxiliary

building, toassurethecapability toachievesafeshutdowninaccordance with10CFR50AppendixRandBTP9.5-1AppendixA.Thebarriersandassociated penetration sealsarepassivedevicesandarepartoftheplantfireprotection system.NRGF0AM366AI4-95I C,4NRCFORM366AI4-9SILICENSEEEVENTREPORT(LER)TEXTCONTINUATION U.S.NUCLEARREGULATORY COMMISSIO STLUCIEUNIT205000389YEARSEQUENTIAL REVISION97-004-03OF4TEXT/Ifmorespeceisrequired, useedditionel copiesofNRCForm366AJl17)Theceramicfiberbetweenthecablesisanextension oftheMariniteboard(ceramicfiberboard)firestopface.Thisceramicfiberservestoresistheat,flame,andsmokepropagation throughthefirestop.Inconjunction withtheflameretardant thisisaneffective threehourfireratedassembly.

(SeeFigure1fortypicaldesigndetails).

However,withouttheceramicfiberbetweenthecablesapathforheatandsmokepropagation isprovided.

Thisisasmallandtortuouspathinthatthespacebetweenthecablesistypically small.Theheatwouldstillneedtotravelatleastonefootdownthetraywheretheflameretardant isapplied,thenwouldenteralargeopenspaceinthewall,andwouldthenneedtoexitthroughanotherfootofconfinedspacebetweencablesonthenon-firesideoftheassembly.

Localized hotspotswouldexist.TheIEEE-383cableswillresisttheeffectsoftheincreased temperatures andhelptopreventtheignitionofcableinthenon-firesideoftheassembly.

Thetwosidedcabletrayfirestopdeficiencies wereevaluated anddetermined tobenotsafetysignificant.

Although'the as-foundcondition ofthesecabletrayfirestopswasnotinaccordance withthetestedanddesignconditions, andwouldprobablynotmeetathreehourfireratingwithouttheceramicfiberbetweenthecables,theinstallation doesprovideresistance tofirepropagation.

Inaddition, fireprotection defenseindepthprovidesanintegrated meansformitigating theconsequences ofafire,suchastheexistingsmokedetection systems,automatic waterfiresuppression systems,hosestations, administrative programsthatcontrolcombustible loading,andoperatoractions.Basedontheabove,itisconcluded thatthehealthandsafetyofthepublicwerenotadversely affectedbythecondition oftheSt.LucieUnit2twosidedcabletrayfirestopassemblies.

Thehourlyfirewatchpatrolswereestablished tocompensate fortheinoperable twosidedcabletrayfirestopassemblies asrequiredbyplantadministrative procedures.

FPLwilleitherreworktheassociated firestopassemblies totheiroriginaldesignordevelopandimplement anewdesigntorestorethedegradedbarrierstoathreehourfirebarrierrating.None.

NRCFORM366AI495ILICENSEEEVENTREPORT(LER)TEXTCONTINUATION U.S.NUCLEARREGULATORY COMMISSIO STLUCIEUNIT205000389YEARSEQUENTIAL REVISION97-004-04OF4TEXT(ifmorespoceisrequired, usoadditional copiesofNRCArm3MAlI17)TWO-SIDED CABLETRAYSEALINFLOOR/WALL OPENINGFIRESTOP2"CERAMICFIBERPLUGSFLAMERETARDANT MARINITE-IBOARDFLAMERETARDANT (MJOWO!ee RotFigure1TypicalTwoSidedCableTrayFireStopAssembly