ML17264A991

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LER 96-009-02:on 960723,determined That Leak Rate Outside Containment Was Greater than Program Limit.Caused by Weld Defect.Isolated Leak & Cut Out & Replaced Leaking Pipe
ML17264A991
Person / Time
Site: Ginna Constellation icon.png
Issue date: 08/11/1997
From: ST MARTIN J T
ROCHESTER GAS & ELECTRIC CORP.
To:
Shared Package
ML17264A990 List:
References
LER-96-009, LER-96-9, NUDOCS 9708180050
Download: ML17264A991 (12)


Text

NRCRORM366(4-95)U.S.NUCLEARREGULATORY COMMISSIO LICENSEEEVENTREPORT(LER).(Seereverseforrequirednumberofdigits/characters foreachblock)APPROVEDBYOMBNO.3150-0104

'XPIRES04/30/96ESTIMATED BURDENPERRESPONSEToCOMPLYWITHTHISMANDATORY INFORMATION COLLECTION REQUEST:50.0HRS.REPORTEDLESSONSLEARNEDAREINCORPORATED INTOTHELICENSING PROCESSANDFEDBACKToINDUSTRY.

FORWARDCOMMENTSREGARDING BURDENESTIMATEToTHEINFORMATION ANDRECORDSMANAGEMENT BRANCHIT-6F33),U.S.NUCLEARREGULATORY COMMISSION, WASHINGTON, Dc20555-0001, ANDToTHEPAPERWORK REDUCTION PROJECTFACILITYNAME(1)TITLE(4)R.E.GinnaNuclearPowerPlantDOCKETNUMBER(2) 05000244PAGE(3)1OF7LeakOutsideContainment, DuetoWeldDefect,ResultsinLeakRateGreaterThanProgramLimitMONTHDAYYEAREVENTDATE(5)LERNUMBER(6)SEQUENT)AL REVISIONNUMBERNUMBERMONTHDAYYEARREPORTDATE(7)FACILITYNAMEOTHERFACILITIES INVOLVED(6)DOCKETNUMBER07239696-009-02081197FACILITYNAMEDOCKETNUMBEROPERATING MODE(9)POWERLEVEL(10)10020.2201(b) 20.2203(a)(1) 20.2203(a)

(2)(i)20.2203(a)

(2)(v)20.2203(a)

(3)(i)20.2203(a)(3)(ii) 50.73(a)(2)(i)50.73(a)(2)

(ii)50.73(a)(2)(iii)SUANTTOTHEREQUIREMENTS OF10CFRE:(ChackoneorTHISREPORTISSUBMITTED PURmore)(11)50.73(a)(2)(viii) 50.73(a)(2)(x) 73.7120.2203(a)

(2)(ii)20.2203(a)(2)(iii) 20.2203(a)(2)(iv) 20.2203(a)(4) 50.36(c)(1)50.36(c)(2)LICENSEECONTACTFORTHISLER(12)50.73(a)(2)(iv)50.73(a)(2)(v) 50.73(a)(2)(vii)OTHERSpecifyInAbet(ectbeloworinNRCForm365ATELEPHONE NUMBER(lne)udeAfeeCode)JohnT.St.Martin-Technical Assistant (716)771-3641COMPLETEONELINEFOREACHCOMPONENT FAILUREDESCRIBED INTHISREPORT(13)CAUSESYSTEMCOMPONENT MANUFACTURER REPORTABLE ToNPRDSCAUSESYSTEMCOMPONENT MANUFACTURER REPORTABLE ToNPRDSBBEPSF0000N:;t~g:~i'~c)NI."i?';.:

SUPPLEMENTAL REPORTEXPECTED(14)YES(Ifyas,completeEXPECTEDSUBMISSION DATE).XNOEXPECTEDSUBMISSION DATE(16)MONTHDAYYEARABSTRACT(Limitto1400spaces,i.e.,approximately 15single-spaced typewritten lines)(16)OnJuly23,1996,atapproximately 0857EDST,itwasdetermined thattheleakrate(fromaleakonapipingsystemoutsideContainment) wasgreaterthantheanalyzedvalueoftwogallonsperhourforaprimarycoolantsourceoutsideContainment.

Immediate corrective actionwastoconservatively enterTechnical Specification LimitingCondition forOperation 3.0.3andinitiateaplantshutdown, andtoinitiateactionstoisolatetheleakusingafreezeseal.Oncetheleakwasisolated, theplantexitedTechnical Specification 3.0.3andtheshutdownwasstopped.Theleakingpipewascutoutandreplaced.

Theunderlying causeoftheleakwasawelddefectwhichdatesbacktooriginalconstruction inthe1960's.ThiseventisNUREG-1022 CauseCode(B).Corrective actiontopreventrecurrence isoutlinedinSectionV.B.Additional corrective actionsareidentified inthissupplement.

9708i80050 9708iiPDRADOCK050002448,PDR

NRCFORM366A(4.95)LICENSEEEVENTREPORT(LER)TEXTCONTINUATION U.S.NUCLEARREGULATORY COMMISSION FACILITYNAMEI1)R.E.GinnaNuclearPowerPlantDOCKET05000244LERNUMBERIe)YEARSEQUENTIAL REVISIONNUMBERNUMBER96-009-02PAGEI3)2OF7TEXT(IImorespaceisrequired, useadditional copiesofNRCForm366AJ(17)I.PRE-EVENT PLANTCONDITIONS:

OnJuly22,1996,theplantwasinMode1atapproximately 100%steadystatereactorpower.Atapproximately 1130EDST,aRadiation Protection (RP)technician, whowasperforming aroutineweeklysurve'yoftheAuxiliary

Building, observedwaterdrippinginanareabehindtheRefueling WaterStorageTank(RWST).TheRPtechnician notifiedtheControlRoomoperators.

Effortstolocatethesourceofthedrippingwaterandtoquantifytheleakratewereinitiated byOperations andNuclearEngineering Services(NES).Thesourceofwaterwasdetermined tobeasmallleakonatestlinefortheContainment Spray(CS)systemintheAuxiliary

Building, whichisoutsidetheContainment (CNMT)~Theleakratewasestimated tobeapproximately one(1)gallonperhour(GPH).TheControlRoomoperators didnotidentifyanyrequirement thatwouldlimitplantoperations.

TheShiftSupervisor notifiedOperations management, maintenance management, andplantandNESstaffoftheleak.Allreachedasimilarconclusion.

Thestaffworkedondeveloping andimplementing anactionplantoaddresstheproblem.Theissuesoflineintegrity andRWSToperability wereinvestigated byNESandLaboratory Inspection Services(LIS)personnel.

LISpersonnel measuredtheamountofpipecross-section andweldmetalremaining, andNESpersonnel determined thattherewasamplemetalintheaffectedareatoprovidesystemintegrity.

Thesourceoftheleakwasidentified asasmallpinholeleakonapipe-to-90 degreeforgedsocketelbowweldonatwo(2)inchnominalpipesizeSchedule10stainless steeltestlinefortheCSsystem.TheleakwasinapartoftheCSsystemthatcouldnotbeisolatedfromtheRWSTbyvalvemanipulations withoutmakingbothtrainsoftheemergency corecoolingsystem(ECCS)inoperable.

Theleakwasmonitored throughout theremainder ofthedayandnight.Anoperability assessment hadbeenrequested bytheShiftSupervisor onJuly22,whentheexistence oftheleakhadfirstbeenidentified.

OnthemorningofJuly23,1996,thisassessment wasreviewedbythePlantOperations ReviewCommittee (PORC)~Thisassessment, whichwasbasedonconservative assumptions, concluded thattheRWSTandECCSwerestilloperablewiththeunisolated leak.Thisconclusion wassupported bythefactthattherewasstillamplemetalareainthecross-section thatcouldprovideintegrity ofthepipeduringaseismiceventandthatthetotalcombinedstresswaslessthantheyieldstrengthofthematerial.

PORCrequested amoreaccurateestimateoftheleakrate.Theleakratewasmeasuredandestimated tobe2.6GPH.Thisleakrateisinexcessoftwo(2)GPH,whichisspecified inSurveillance TestProcedure PT-39,"LeakageEvaluation ofPrimaryCoolantSourcesOutsideContainment",

astheprogramlimitforthemaximumintegrated leakrateoutsideCNMTfromthesesources.Sincetheleakrateexceededtherequirements ofprocedure PT-39,itwasinitially judgedtobeaviolation ofthe"PrimaryCoolantSourcesOutsideContainment Program",

asspecified intheGinnaStationImprovedTechnical Specifications (ITS)Section5.5.2.ThePORCchairmandirectedtheShiftSupervisor toenterITSLimitingCondition forOperation (LCO)3.0.3,basedontheconservative requirements ofprocedure PT-39andAdministrative Procedure A-52.4,"ControlofLimitingConditions forOperating Equipment",

eventhoughtheplantwasincompliance withallITSLCOs.NACFOAM356AI4-95)

NRCFORM366A(4-95)LICENSEEEVENTREPORT(LER)TEXTCONTINUATION U.S.NUCLEARREGULATORY COMMISSION FACILITYNAME(1)DOCKETLERNUMBER(6)PAGE(3)R.E.GinnaNuclearPowerPlant05000244YEARSEQUENTIAL REVISIONNUMBERNUMBER3OF796-009-02TEXTiifmorespaceisrequired, useaddiu'onal copiesofNRCForm366AJ(17)DESCRIPTION OFEVENT:A.DATESANDAPPROXIMATE TIMESOFMAJOROCCURRENCES:

oJuly22,1996,1130EDST:Aleakisidentified onalineoutsideofContainment.

July23,1996,0857EDST:EventDateandTimeandDiscovery DateandTime.July23,1996,0900EDST:Loadreduction isstarted.July23,1996,1440EDST:Integrated leakageoutsideContainment isdetermined tobelessthantwoGPH.Loadreduction isstopped.B.EVENT:OnJuly23,1996,atapproximately 0857EDST,withtheplantinMode1atapproximately 100%steadystatereactorpower,thePlantOperations ReviewCommittee (PORC)conservatively directedtheShiftSupervisor toenterITSLCO3.0.3.:TheShiftSupervisor directedtheControlRoomoperators toinitiateaplantshutdown.

Atapproximately 0900EDST,theControlRoomoperators initiated aplantshutdownperNormalOperating Procedure 0-2,1,"NormalShutdowntoHotShutdown".

TheMechanical Supportgroupinitiated actionstoprovideafreezesealtoisolatethesourceofleakagefromtheRWST.Afreezesealwasinitiated betweentheleakingsocketandtheCSpumpsuctionlinefromtheRWST.Atapproximately 1440EDSTonJuly23,1996,thefreezesealhadisolatedtheleak.ITSLCO3.0.3wasexitedandtheloadreduction wasstopped.Theaffectedpipeandsocketweldswerecutoutandanewprefabricated spoolpiece wasinstalled.

Theaffectedweldwasretainedforfailuremodeanalysis.

Aloadincreasetoreturntheplanttofullpowerwasinitiated atapproximateiy 1530EDSTonJuly23,1996.C.INOPERABLE STRUCTURES, COMPONENTS, ORSYSTEMSTHATCONTRIBUTED TOTHEEVENT:NoneD.OTHERSYSTEMSORSECONDARY FUNCTIONS AFFECTED'ue tothelocationandsizeoftheleak,anoperability assessment determined thatnoemergency safeguards systemfunctionwasmadeinoperable.

However,theleakwasnotisolablefromtheRWSTwithoutvalvemanipulations thatwouldhaveresultedintheinoperability oftheRWSTandbothtrainsoftheECCS.NACFOAM366A(4-95)

NRCFORM366A(4-95)LICENSEEEVENTREPORT(LER)TEXTCONTINUATION U.S.NUCLEARREGULATORY COMMISSION FACILITYNAME(1)R.E.GinnaNuclearPowerPlantDOCKET05000244LERNUMBER(6)YEARSEQUENTIAL REVISIONNUMBERNUMBER96-009-02PAGE(3)4OF7TEXTiifmorespaceisrequired, useedditionalcopiesofNRCForm368A)(17)E.METHODOFDISCOVERY:

Theleakwasfirstdiscovered byanRPtechnician duringaroutineweeklysurveyoftheAuxiliary Building.

'enotifiedtheControlRoomoperators, andthepreciselocationwasconfirmed byOperations andEngineering.

Confirmation thattheleakratewasabove2GPHoccurredaftermeasurements performed atthedirection ofPORC.OPERATORACTION:WhennotifiedbyPORC,theShiftSupervisor directedtheControlRoomoperators toenterITSLCO3.0.3andtoinitiateaplantshutdown.

'heControlRoomoperators initiated aplantshutdownperprocedure 0-2.1.TheShiftSupervisor subsequently notifiedtheNRCper10CFR50.72(b)(1)(i)(A),non-emergency onehournotification, atapproximately 0951EDSTonJuly23,1996.Whentheleakwasisolated, ITSLCO3.0.3wasexited,andtheplantwasreturnedtofullpower.G.SAFETYSYSTEMRESPONSES:

NoneIII.CAUSEOFEVENT:A.IMMEDIATE CAUSE:Theimmediate causeofthecondition prohibited byTechnical Specifications wastheconservative determination byPORCtoenterITSLCO3.0.3duetotheteak.B.INTERMEDIATE CAUSE:Theintermediate causeoftheleakwasapinholeleakintheweldattaching thepipetothesocketelbow.C.ROOTCAUSE:Theaffectedpipe,socket,andfilletweldwereanalyzedforthefailuremode.Thepinholewasdetermined tobeanoriginalinstallation welddefect(datingfromthe1960's)thatexistedoveranareaofslaginclusion intheweld.Almostalltheslaghadbeenleachedfromthepinholechanneloverthe'ast25years.NACFOAM366A(4.95)

NRCFORM366A(4-95)LXCENSEEEVENTREPORT(LER)TEXTCONTINUATION U.S.NUCLEARREGULATORY COMMISSION FACILITYNAME(1)DOCKETLERNUMBER(6)PAGE(3)R.E.GinnaNuclearPowerPlant05000244YEARSEQUENTIAL REVISIONNUMBERNUMBER5OF796-'-009-02TEXTilfmorespeceisrequired, useedditionel copiesofNRCForm366AJ(17)ThiseventisNUREG-1022 CauseCode(B),"Design,Manufacturing, Construction

/Installation".

ThesmallpinholeleakdoesnotmeettheNUMARC93-01,"Industry Guideline forMonitoring theEffectiveness ofMaintenance atNuclearPowerPlants",definition ofa"Maintenance Preventable Functional Failure"~IV.ANALYSISOFEVENT:Thiseventisreportable inaccordance with10CFR50.73,LicenseeEventReportSystem,item(a)(2)(i)(B),"Anyoperation orcondition prohibited bytheplant'sTechnical Specifications".

Theintegrated leakrateinexcessof2GPHoutsideCNMTresultedinconservative entryintoITSLCO3.0.3.ITSLCO3.0.3isonlyapplicable torequirements contained inChapter3oftheITS.Therewasnolicenserequirement forentryintoITSLCO3.0.3.Nevertheless, sincetheplantvoluntarily enteredITSLCO3.0.3,thiscondition isreportable.

Anassessment wasperformed considering boththesafetyconsequences andimplications ofthisevent.Thefollowing aretheresultsandconclusions ofthisassessment:

Therewerenooperational orsafetyconsequences orimplications attributed totheleakontheCStestlinebecause:Almostalltheslaghadbeenleachedfromthepinholechannelandtherewasnosignofcorrosion orstress(cracking) attackofthestainless steelmaterialadjacenttothepinhole.Sincethepinholedidnotdegradethecross-sectional areaoftheforgedsocketelbowandpipe,thestressesonthislinedue.totheconcurrent loadsofdeadweight,

pressure, seismic,andthermaleffectswerestillwithinthecodelimit.Seismicintegrity wasnotthreatened bytheleaknorbytheinstallation ofthefreezeseal.Thenatureofthisleakmechanism wouldnotleadtoanincreaseinholesizeabovethatinitially identified.

Thelinecontaining theaffectedelbowexperiences flowfromtheRefueling WaterStorageTank(RWST)totheContainment Spray(CS)eductorsuctionvalvesduringperiodicsurveillance testingandisnotsubjected toanyappreciable dynamicstressesduringtesting,norwoulditbeexpectedtoduringpost-accident operation oftheCSorsafetyinjection.

Theoffsiteexposureduetoalargebreaklossofcoolantaccident(LOCA)isanalyzedintheGinnaStationUpdatedFinalSafetyAnalysisReport(UFSAR).Thesubjectleaklocationisexposedtoradioactive sumpfluidfollowing 6smallorlargebreakLOCAduringrecirculation.

NRCFORM366A(4-95)

NRCrORM366A(4-95)LICENSEEEVENTREPORT(LER)TEXTCONTINUATION U.S.NUCLEARREGULATORY COMMISSION FACILITYNAME(1)R.E.GinnaNuclearPowerPlantDOCKET05000244LERNUMBER(6)YEARSEQUENTIAL REVISIONNUMBERNUMBER96-009-02PAGE(3)6OF7TEXTlifmorespaceisrequired, useadditional copiesofNRCForm386A/(17)Recentanalyseshavebeenperformed byWestinghouse torecalculate siteboundaryandcontrolroomdosesfromalargebreakLOCA,whichisthemostlimitingLOCAsizefordoseevaluations.

Withanassumedrecirculation leakrateof2.75GPH,itwasdetermined thatthesiteboundaryandlowpopulation zonethyroidandwholebodydosesresulting fromthepostulated largebreakLOCAarewithinthe10CFR100doseguidelines of300REMthyroidand25REMwholebody,respectively.

TheControlRoomdosecalculations resultinaControlRoomthyroid,wholebodyandbetaskindosewithinthedoselimitsdefinedintheNRCStandardReviewPlan(SRP)Section6.4,whichare30REMthyroid,5REIVIwholebodyand30REMbetaskin.Thesecalculated dosesarealsowithinthedosevaluesstatedintheUFSAR.Basedontheabove,it'canbeconcluded thatthepublic'shealthandsafetywasassuredatalltimes.V.CORRECTIVE ACTION:A.ACTIONTAKENTORETURNAFFECTEDSYSTEMSTOPRE-EVENT NORMALSTATUS:0ThesourceoftheleakagewasisolatedfromtheRWSTbyfreezeseal,permitting exitfromITSLCO3.0.3.0Theaffectedpipeandsocketweldswerecutoutandreplacedwithanewprefabricated spoolpiece, andthefreezesealwasremoved.B.ACTIONTAKENORPLANNEDTOPREVENTRECURRENCE:

0FailureAnalysisoftheleakinthesocketweldhasbeenperformed.

Theadjacentoriginalexistingweldswerecutoutandreplaced, Additional corrective actionsareidentified inthissupplement andarelistedbelow:ThebasesforITSLCO3.6.1,"Containment",

hasbeenrevisedtospecifythenewleakagelimitof2.75GPHforintegrated leakageoutsideCNMTfromtheresidualheatremoval(RHR),safetyinjection (Sl),andCSsystems,andtoconsidertheeffectofthisleakageonCNMToperabiity.

2.TheprogramlimitforleakageoutsideCNMT,asstatedinprocedure PT-39,wasrevisedfrom2.0GPHto2.75GPH,toreflectthesenewleakagelimits.3.Procedure A-52Awasrevisedtoreflectthenewprogramlimit:theintegrated leakagemustbe<I=2.75GPHasdetermined byPT-39.Theconservative requirement toenterITSLCO3.0.3forleakageabovethislimitwaseliminated.

NACFOAM366A(4-95)

NRCFORM366AI4.95)LXCENSEEEVENTREPORT(LER)TEXTCONTINUATION U.S.NUCLEARREGULATORY COMMISSION FACILITYNAME<1)R.E.GinnaNuclearPowerPlantDOCKET05000244LERNUMBERI6)YEARSEQUENTIAL REVISIONNUMBERNUMBER96-009-02PAGEI3)7OF7TEXTllfmorespaceisrequired, useadditional copiesofNRCForm866AJl17)Vl.ADDITIONAL INFORMATION:

A.FAILEDCOMPONENTS:

Thefailedcomponent wasa2inchnominalpipesizeSchedule10pipe-to-90 degreeforgedsocketelbowweld.Thepipeandsocketelbowarestainless steel,ASTMA312Type304andA182F304(forged)respectively.

Thesocketweldwasanoriginalinstallation weldmadebefore1970.B.PREVIOUSLERsONSIIVIILAR EVENTS:AsimilarLEReventhistorical searchwasconducted withthefollowing results:Nodocumentation ofsimilarLEReventswiththesamerootcauseatGinnaNuclearPowerPlantcouldbeidentified.

C.SPECIALCOMMENTS:

NoneNRCFORM366AI4.95)

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