ML17229A539

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LER 97-010-00:on 971027,inadvertant Core Alteration Prohibited by TS Occurred.Caused by CEA Failure to Detach from Ugs.Safety Evaluation Was Performed & Procedural Rev Made to Continue Upper Guide Structure move.W/971126 Ltr
ML17229A539
Person / Time
Site: Saint Lucie NextEra Energy icon.png
Issue date: 11/26/1997
From: REVELL J, STALL J A
FLORIDA POWER & LIGHT CO.
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
L-97-297, LER-97-010, LER-97-10, NUDOCS 9712030199
Download: ML17229A539 (6)


Text

CATEGORY1SREGULATEYINFORMATION DISTRIBUTION STEM(RIDS)ACCESSION NBR:9712030199

,DOC.DATE:

97/11/26NOTARIZED:

NOFACXL:50-335 St.LuciePlant,Unit1,FloridaPower&LightCo.AUTH.NAMEAUTHORAFFILIATION REVELL,J.

FloridaPower&LightCo.STALL,J.A.

FloridaPower&LightCo.RECIP.NAME RECIPIENT AFFILIATION DOCKET¹05000335

SUBJECT:

LER97-010-00:on 971027,inadvertant corealteration prohibited byTSoccurred.

CausedbyCEAfailuretodetachfromUGS.Safety evaluation wasperformed

&procedural revmadetocontinueUGSmove.W/971126 ltr.DISTRIBUTION CODE:IE22TCOPIESRECEIVED:LTR iENCLSIZE:l5TITLE:50.73/50.9 LicenseeEventReport(LER),IncidentRpt,etc.NOTES:ERECIPIENT 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:

LSTLOBBYWARDNOACPOORE,W.NRCPDRCOPIESLTTRENCL111111111111111111111111RECIPIENT IDCODE/NAME WIENS,L.ILECENTNRRNRR/DRCH/HHFB NRR/DRCH/HOLB NRR/DRPM/PECB NRR/DSSA/SRXB RGN2FXLE01LITCOBRYCE,JHNOACQUEENER,DS NUDOCSFULLTXTCOPIESLTTRENCL1122111111111111'111111110D0UNOTETOALL"RIDS"RECZPZENTS PLEASEHELPUSTOREDUCEWASTE.TOHAVEYOURNAMEORORGANIZATION REMOVEDFROMDISTRIBUTION LISTSORREDUCETHENUMBEROFCOPIESRECEIVEDBYYOUORYOURORGANIZATION, CONTACTTHEDOCUMENTCONTROLDESK(DCD)ONEXTENSION 415-2083FULLTEXTCONVERSION REQUIREDTOTALNUMBEROFCOPIESREQUIRED:

LTTR25ENCL25 FloridaPower&LightCompany,650tSouthOceanDrive,JensenBeach,FL34957FPLNovember26,1997L-97-29710CFR50.73U.S.NuclearRegulatory Commission Attn:DocumentControlDeskWashington, D.C.20555Re:St.LucieUnit1DocketNo.50-335Reportable Event:97-010DateofEvent:October27,1997Inadvertant CoreAlteration Prohibited byTechnical Specifications DuetoStuckControlElementAssemblCEATheattachedLicenseeEventReportisbeingsubmitted pursuanttotherequirements of10CFR50.73toprovidenotification ofthesubjectevent.Verytrulyyours,J.A.StallVicePresident St.LuciePlantJAS/JWRAttachment cc:RegionalAdministrator, USNRC,RegionIISeniorResidentInspector, USNRC,St.LuciePlant,ijc4/97i2030i'tt9 97ii26PDRADQCK050003358PDRlbltttliltjtlllttltajiNI anFPLGroupcompany NRCFORM366(4.95)U.S.NUCLEARREGULATORY COMMISSION LICENSEEEVENTREPORT(LER){Seereverseforrequirednumberofdigits/characters foreachblock)APPROVEDBYOMBNo.31604I104 EXRRES04I30/SSESTIMATED BURDENPERRESPONSETOCOMPLYWITHTHISMANDATORINFORMATION COLLECTION REQUEST:60.0HRS.REPORTEDLESSONLEARNEDAREINCORPORATED INTOTHEUCENSINGPROCESSANDFEBACKTOINDUSTRY.

FORWARDCOMMINTSREGARDING BURDENESTIMATTOTHEINFORMATION ANDRECORDSMANAGEMENT BRANCHIT.SF33)US.NUCLEARREGIAATORY COMMISSION.

WASHINGTON.

DC206664001 ANDTOTHEPAPERWORK REDUCTION PROJECT13160%1041, OFFICEOIMANAGEMENT ANDBUDGET.WASHINGTON.

DC20603.FACIUTYNAMEHiSTLUCIEUNIT1DOCKETNUMBER12105000335PAGE1311OF4TITLE(41Inadvertant CoreAlteration Prohibited byTechnical Specifications DuetoStuckControlElementAssembly(CEA)MONTHDAY1027OPERATING MODE(9)POWERLEVEL{10)97000SEQUENTIAL REVISIONNUMBERNUMBER97-010-0020.2201(b)20.2203(0)(2)(I)20.2203(a)

(2)(iii)20.2203(0)(2)(iv)MONTHOAY112620.2203{a)(2)(v) 20.2203(a)

(3)(ii)50.36(c)(1) 50.36(c)(2)

YEAR97FACILIlYNAMEFACILITYNAME50.73(a)(2)(i)50.73(a)(2)(iii) 50.73(a)(2)(v)50.73(a)(2)(vii)

DOCKETNUMBER DOCKETNUMBER 50.73(a)(2)(viii)73.71OTHERSpecifyinAbstractbefoworinNRCForm366ANAMEJackRevell,Licensing EngineerTELEPHONE NUMBERSncludeAreaCode)(561)467-7169CAUSESYSTEM.COMPONENT MANUFACTURER REPORTABLE TONPRDSCAUSESYSTEMCOMPONENT MANUFACTURER REPORTABLE TONPRDSACRCTC490XYES{Ifyes,completeEXPECTEDSUBMISSION DATE).NoEXPECTEDSUBMISSION DATE{15)MONTHOAYYEAR020498ABSTRACT(Limitto1400spaces,i.e.,approximately 15single-spaced typewritten lines){16)OnOctober27,1997,St.LucieUnit1wasinMode6withthereactorheadremovedinpreparation fordefueling.

Thecontainment equipment hatchandpersonnel accessairlockwereopen,asallowedbyTechnical Specifications.

Personnel commenced UpperGuideStructure (UGS)withdrawal fromthereactorvesselinaccordance withprocedures.

AstheUGSclearedthealignment pins,aControlElementAssembly(CEA)wasdiscovered attachedtotheUGS,andhadbeenunexpectedly withdrawn fromthecore.Thisconstituted acorealteration withoutthecontainment penetration statusrequiredbyTechnical Specifications.

Containment integrity wassetwithinabout20minutesofdiscovery ofthestuckCEA.ThecauseoftheCEAremaining attachedtotheUGScouldnotimmediately bedetermined.

Asafetyevaluation wasperformed andaprocedural revisionmadetocontinuetheUGSmove.Reactorcavitywaterlevelwasraisedtoincreaseshielding.

Anticipating elevatedcontainment radiation levels,theContainment Isolation System(CIS)wasmanuallyactuatedpriortocontinuing thelift.TheUGSliftrecommenced onOctober28.AremotecamerasituatedbeneaththeUGSmonitored theprogress, andtheCEAremainedattachedthroughout thetransit.Oncethetransittotherefueling cavitywascompleted, theCEAwasrecovered fromtheUGS.Therootcauseoftheeventisstillunderinvestigation.

Furthercorrective actionswillbeidentified oncetherootcauseisdetermined.

NRCFORM366(4-95)

NRCFORM366A(4.95)LICENSEEEVENTREPORT(LER)TEXTCONTINUATION U.S.NUCLEARREGULATORY COMMISSIO STLUCIEUNIT105000335YEARSEQUENTIAL REVISION97-010-002OF4TEXTilfmorespeceisrequired, useeddnionel copiesofNRCForm366A/I17IDESCRIPTION OFTHEEVENTOnOctober27,1997,St.LucieUnit1wasinMode6withthereactorhead[EIIS:AB:RCT]

removedinpreparation forreactordefueling.

Thecontainment equipment hatchandpersonnel accessairlock[EIIS:NH]

wereopen,asallowedbyTechnical Specifications.

ControlElementAssemblies (CEAs)[EIIS:AA]

hadbeenunlatched bypersonnel inaccordance withprocedure OP1-0110022,

'Coupling'and Uncoupling ofCEAExtension Shafts'.Atapproximately 1510,thereactorcavitywaterlevelwasraisedto55feet6inchestomaintainadequateshielding inpreparation forliftingtheUpperGuideStructure (UGS)[EIIS:AC].

Normallyduringthelift,onlytheUGSliftrigisraisedabovethesurfaceofthewater.Atapproximately 1658,contractpersonnel commenced UGSwithdrawal fromthereactorvesselinaccordance withprocedure 1-M-0015,

'ReactorVesselMaintenance

-SequenceofOperations'.

Duringtheevolution, acameramountedatthereactorvesselflangelevelwasusedtoverifyliftalignment andclearance.

Atapproximately 1744,astheUGSclearedthealignment pins,aCEAwasdiscovered attachedtotheUGS,andhadbeenunexpectedly withdrawn fromthecore.Operations orderedcontainment integrity tobeset,andthiswasachievedby1805.ThecauseoftheCEAremaining attachedtotheUGScouldnotimmediately bedetermined.

Asafetyevaluation wasperformed whichconcluded thattherewouldbenoadverseimpactonplantsafetyoroperation shouldtheCEAfallontothecorewhilecompleting theUGSmove.Procedure 1-M-0015,

'ReactorVesselMaintenance-SequenceofOperations',

wasrevisedtoaccommodate movementoftheUGSwithaCEAattached.

SincetheUGSandliftrigweretobeliftedmuchhigherthannormal,reactorcavitywaterlevelwasadjustedto60feettoincreaseshielding.

Thisactionwascompleted atapproximately 2222hours.Inanticipation ofreceiving highenoughcontainment radiation levelstoinitiateaContainment Isolation Actuation Signal(CIAS),unnecessary personnel leAcontainment andtheContainment Isolation System(CIS)[EIIS:JM]

wasmanuallyactuatedatapproximately 0253onOctober28.Thiswasapreplanned actuation performed inaccordance withprocedure OP1-1600023,

'Refueling Sequencing Guidelines'.

NACFOAM366AI4.95)

NRCFORM366AI4.96)LICENSEEEVENTREPORT(LER)TEXTCONTINUATION U.S.NUCLEARREGULATORY COMMISSIO STLUCIEUNIT105000335YEARSEQUENTIAL REVISION97-010-003OF4TEXTflfmorespeceisrequired, useedditionel copiesofNRCForm366A/I17)TheUGSliftrecommenced atapproximately 0320withonlyessential personnel incontainment.

AremotecamerasituatedbeneaththeUGSmonitored theprogress, andtheCEAremainedfirmlyattachedthroughout thetransit.Atapproximately 0324,CIASchannelsindicated thatcontainment radiation levelshadreachedtheCIASinitiation threshold.

ChannelMD,withthemostdirectexposuretotheUGS,registered anarearadiation rateofapproximately 7REMperhour,whiletheotherthreechannelsindicated approximately 100milliremperhour.CISactuatesautomatically withtwochannelsgreaterthanorequalto90milliremperhour.Oncethetransittotherefueling cavitywascompleted, attemptsweremadetofreetheCEAbutwereinitially unsuccessful.

Subsequently, theCEAwasdisengaged byoperating personnel.

TheCEAwasretrieved andmovedtothespentfuelpoolforstorage.Itwasidentified asCEA24,aType1,fulllengthCEAmanufactured byCombustion Engineering.

CAUSEOFTHEEVENTThecauseoftheeventwasfailureoftheCEAtodetachfromtheUGS.Itiscurrently undetermined whethertheCEAwaspartially latchedorfrictionfittotheCEAExtension Shaft.Therootcauseisstillunderinvestigation.

Asupplement tothisLERwillbeissueddescribing thefindingsofrootcauseevaluation forthestuckCEA.ANALYSISOFTHEEVENTThiseventisreportable under10CFR50.73(a)(2)(i)(B) as"Anyoperation orcondition prohibited bytheplant'sTechnical Specifications."

TheTechnical Specification violatedisUnit1Technical Specification 3.9.4:"Thecontainment penetrations shallbeinthefollowing status:a.Theequipment doorclosedandheldinplacebyaminimumoffourbolts,b.Aminimumofonedoorineachairlockisclosed,andC.Eachpenetration providing directaccessfromthecontainment atmosphere totheoutsideatmosphere shallbe...(severalconfigurations given).APPLICABILITY:

DuringCOREALTERATIONS ormovementofirradiated fuelwithinthecontainment."

NRCFORM366AI4.96)

NRCFORM366AI4-95)LICENSEEEVENTREPORT(LER)TEXTCONTINUATION U.S.NUCLEARREGULATORY COMMISSIO STLUCIEUNIT105000335YEARSEQUENTIAL REVISION97-010-004OF4TEXTllfmorespaceisrequired, useadditional copiesofNRCForm366A/I17ITheTechnical Specifications define"corealteration" as"movement ormanipulation ofanyfuel,sources,reactivit controlcomponents, orothercomponents affecting reactivity withinthereactorvesselwiththevesselheadremovedandfuelinthevessel."Normally, liftingaUGSisnotacorealteration, sincetheUGSdoesnotcontainfuel,sources,orcomponents thatcontroloraffectreactivity.

However,sinceareactivity controlcomponent (aCEA)wasmovedwiththeUGSinthisevent,acorealteration wasperformed.

Moreover, thecorealteration wasperformed withoutthecontainment penetration statusrequiredbytheTechnical Specification.

Penetrations wereplacedintherequiredstatewithinapproximately 20minutesofdiscovery ofthestuckCEA.TheCISactuation wasnotreportable under10CFR50.72,sincetheactuation waspartofapreplanned sequenceaddressed byprocedure.

TheCISisdesignedtomitigatetheconsequences ofaccidents whichreleaselargeamountsofenergywithinthecontainment structure.

Therewasnosuchaccidentinthiscase,andtheCISactuation wasintentional ratherthantheresultofaccidentconditions.

Withdrawal ofthestuckCEAfromthereactorcoredidnotplacetheplantinanunanalyzed condition, nordiditplacetheplantinacondition outsideitsdesignbasis.Plantprocedures addressthecaseofasingleCEAnotinsertedinthecore,andsubstantial shutdownmarginwasmaintained duringthecourseofthisevent.LER97-001-00 forSt.LucieUnit2documented aneventwithradiological conditions similartothisevent.IntheUnit2event,anexpectedCISactuation occurredastheUGSwaswithdrawn fromthereactor.Theelevatedradiation levelswerecausedbyirradiated incoreinstrumentation segments[EIIS:IG]

whichhadbrokenduringremovalofincores.TheUnit2event,however,wasunlikethiseventinthattherewasnocorealteration.

ICORRECTIVE ACTIONSImmediate corrective actionsincludedstoppingtheUGSliftandevaluating doserates.Acondition reportwasissuedandateamwasdesignated todetermine thecauseofthestuckCEA.Theteamreviewedpotential failuremodesandrelatedindustryexperience, buthasnothadaccesstotheCEA'sextension shaftforevaluation.

Theunlatchprocedure wasalsoreviewedandverifiedtohavebeenproperlyperformed.

Furthercorrective actionsforthestuckCEAwillbeidentified inasupplement tothisLERoncetherootcausehasbeendetermined.

NACFOAM366AI4.95)