ML17331B354

Forwards SG Tube Inspections Prior to Startup Rept, Containing Category C-3 Rept,Required by TS 4.4.5.5(c), Including Followup Investigations & Subsequent Repairs Formed

ML17331B354
Person / Time
Site:	Cook
Issue date:	04/18/1994
From:	FITZPATRICK E INDIANA MICHIGAN POWER CO. (FORMERLY INDIANA & MICHIG
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
AEP:NRC:1166I, NUDOCS 9404210285
Download: ML17331B354 (12)

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ACCELERATEDDISTRIBUTIONDEMONSTRATIONSYSTEM~~lREGULATORYINFORMATIONDISTRIBUTIONSYSTEM(RIDS)ACCESSXONNBR:9404210285DOC.DATE:94/04/18NOTARIZED:NODOCKETFACIL:50-315DonaldC.CookNuclearPowerPlant,Unit1,IndianaM05000315AUTH.NAMEAUTHORAFFILIATXONFITZPATRICK,E.IndianaMichiganPowerCo.(formerlyIndiana&MichiganEleRECIP.NAMERECIPIENTAFFILIATIONDocumentControlBranch(DocumentControlDesk)SUBZECT:ForwardsSGtubeinspectionspriortostartuprept.Attachment1containsCategoryC-3rept,requiredbyTS4.4.5.5(c),includingfollow-upinvests.gations&subsequentrepairsformed.DISTRIBUTIONCODE:A001DCOPIESRECEIVED:LTRENCLSIZE:TITLE:ORSubmittal:GeneralDistributionDNOTES'ECIPIENTIDCODE/NAMEPD3-1LAHICKMAN,ZCOPIESRECIPIENTLTTRENCLIDCODE/NAME11PD3-1PD22COPIESLTTRENCL11ADDINTERNAL:NRR/DE/EELBNRR/DRCH/HICBNRR/DSSA/SPLBNUDOCS-ABSTRACTOGC/HDS2EXTERNAL:NRCPDR111111111011NRR/DORS/OTSBNRR/DRPWNRR/DSSA/SRXBOC/LFDCB~~&G01NSIC111111101111DNOTETOALL"RIDS"RECIPIENTS:PLEASEHELPUSTOREDUCEWASI'E!CONTACTTHEDOCUMENTCONTROLDESK,ROOMPl-37(EXT.20079)TOELIMINATEYOURNAMEFROMDISTRIBUTIONLISTSFORDOCUMENTSYOUDON'TNEED!TOTALNUMBEROFCOPIESREQUIRED:LTTR16ENCL14DD IndianaMichiganPowerCompanyP.O.Box16631Cofumbus,OH43216AEP:NRC:1166IDonaldC.CookNuclearPlantUnit1DocketNo.50-315LicenseNo.DPR-58STEAMGENERATORTUBEINSPECTIONSPRIORTOSTARTUPREPORTU.S.NuclearRegulatoryCommissionDocumentControlDeskWashington,D.C.20555Attn:W.T.RussellApril18,1994

DearMr.Russell:

PursuanttotherequirementsofDonaldC.CookNuclearPlantTechnicalSpecifications4.4.5.5(c)and(e),thislettertransmitstherequired"priortorestart"reportontheresultsofoureddycurrentinspectionandsubsequentrepairsperformedonthesteamgeneratortubesduringthe1994Unit1RefuelingOutage.Attachment1containstheCategoryC-3report,requiredbyT/S4.4.5.5(c),includingfollow-upinvestigationsandsubsequentrepairsperformed.Attachment2containsthesteamlinebreakleakageanalysisrequiredbyT/S4.4.5.5(e)andprovidestheevaluationoftheprobabilityoftubeburstduringasteamlinebreakcommittedtoinourletterAEP:NRC:1166M,datedFebruary14,1994.Sincerely,ud,~~E.E.FitzpatrickVicePresidentAttachmentsdrcc:A.A.BlindG.CharnoffJ.B.Martin-RegionIIINFEMSectionChiefNRCResidentInspectorJ.R.Padgett9404210285940018PDR,ADOCK0500031S.PDR ATTACHMENT1TOAEP:NRC:1166ICATEGORYC-3REPORT Attachment1toAEP:NRC:1166IPage1CATEGORYC-3INVESTIGATIONTheresultsoftheCookNuclearPlantUnit1refuelingoutageeddycurrentinspectionsforbothbobbincoil.(BC)androtatingpancakecoil(RPC)tubesampleprogramswereprovidedtotheNRCinourletterAEP:NRC:11660,datedMarch30,1994.TheinspectionresultedinaCategoryC-3classification,perTechnicalSpecification4.4.5.5.Theprincipalreasonforthe.C-3classificationwasthenumberofdefectsidentifiedatthehotlegtop-of-tubesheetregionbyRPCinspection.Outsidediameterstresscorrosionciacking(ODSCC)indicationsatthehotlegtopoftubesheetregionhashistoricallybeenanareaofconcernintheUnit1steamgenerators.Reviewofthedatashowsamajorityoftheindications,approximately888,tobebelowthetopoftubesheetinarangefromafewtenthsofaninchto2.25inches.Theremainingindicationswereatorslightlyabovethetopoftubesheetinarangeof0.0inchesto0.7inches.AsaresultofthisRPCinspection,237tubeswereplugged(asnotedinTable1ofAttachment2ofAEP:NRC:11660).ToassistindeterminingthetrendinODSCC,the1992RPCdatawerereviewedusingthe1994analysisguidelines.Thisreviewidentifiedthatapproximately40%oftheindicationswerenewandthatthebalance.werepresentduringthe1992inspection.TheRPCvoltagerangeforthema]orityoftheindicationswaslessthan0'volts.Ingeneral,theindicationstypicallyexhibitedonlyslightchangesindepthand/orvolume.Thedatacollectionduringthe1994inspectionhadahighersignaltonoiseratioandahigherrotatingprobespeedthanin1992,makingtheindicationsmorediscernible.This,coupledwithmoreexperiencedanalystsandimprovedanalysisguidelinesandtrainingassistedintheidentificationoftheselowvoltageindicationsduringthe1994inspection.Althoughitisapparentfromthe1994datathattubecorrosionhasnotcompletelystopped,itiscontinuingataslow,manageablerate.InanefforttocombattheODSCCatthetopoftubesheet,anumberofadditionalremedialmeasureswereemployedthis'efuelingoutage.Twonewprocesseswereaddedtothesteamgeneratorsecondarysidesludgeremovaloperations:sludgeremovalwiththeConsolidatedEdisonCombinedInspectionandLancingSystem(CECIL)andPressurePulseCleaning(PPC).CECILprovidesthecapabilitytoperformsludgeremovaldeepinthetubebundle,usingahighpressuresprayatobservedareasofhardsludgebuildup.PPCprovidestheabilitytoforciblysurgewaterthroughthetubesupportplateopeningsandalsocreatesturbulenceatthetopoftubesheetwhichaidsintheagitationandsoakingofcreviceregions.Thisisinadditionto,theprimaryoh)ectiveofPPC,whichisremovalofsludgedepositsthroughoutthesteamgenerator.Remedialmeasureswhichwillremainineffectincludereactorcoolantsystemreducedpressureandtemperatureoperation,on-lineboricacidaddition,boricacidtubesheetcreviceflushingduringstartup,tubesheetsludgeremoval,andimprovedsecondarysidechemistry.

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~~I~Attachment1toAEP:NRC:1166IPage2The'994eddycurrentinspectionresultswillbereviewedinfurtherdetailinthefollowingmonths,alongwithotheravailableindustryexperience.Thiswillbedonetodevelopanoverallassessmentofsteamgeneratortubeintegrityandtoassesstheneedforanychangestotheremedialmeasuresnowinplace,aswellastoaidinplanningforfuturetubeinspections.

ATTACHMENT2TOAEP:NRC:1166ISTEAMLINEBREAKLEAKAGEANALYSISANDPROBABILITYOFTUBEBURSTEVALUATION Attachment2toAEP:NRC:166IPage1D.C.CookUnit1InterimPluggingCriteriaLetterReportThisreportprovidesasummaryandconclusionsoftheleakrateandburstcalculationsperformedfortheD.C.CookUnit1interimpluggingcriteria.Table1providesasummaryoftheD.C.Cook1projectedEOC-14leakrateresults.SLBleakrateswerecalculatedforatotaloftwelvecases,thecombinationofsixprobability-of-leakcorrelationsandtwoleakratecalculationmethodologies.Thetwoleakratecalculationsarethose'ndraftNUREG-1477andaleakrateversusvoltagecorrelation(regressionanalysis).ThismeetstherequirementsoftheCook-1IPCSERrequirements.TheNRCSERalsospecifiesthattheanalysesaretobebasedonaleakageandburstdatabasethatexcludesoutliersonlyonthebasisofbaddata.ThisguidanceisfollowedfortheSERrequiredanalyses,althoughtheNRCSERdatabasediffersfromtheEPRIdatabaseinthetreatmentofoutliers,Insomecases,suchasthePOLcorrelations,thedifferencesbetweentheNRCandEPRIdatabasesarenegligible.ConsistentwiththeNRCguidanceoftheFebruary8,1994,NRC/Industrymeeting,criteriaweredevelopedandusedtodeletenon-applicabledata.TheSLBleakratesarecorrelatedwithvoltagewithinthestatisticalconfidenceguidelinespresentedatthatmeeting.TheleakratesfortheAPCleakratecorrelationmethodologyareontheorderof100timeslowerthanthoseobtainedbytheNUREGcalculation,whichdoesnotconsiderthecorrelation.LeakagecalculationswerebasedonthecalculatedEOC-14voltagedistributiondeterminedbyapplyingtheCycle13growthdistributiontotheBOC-14indications,usingMonteCarlotechniques.Thiswasperformedforthemorelimitingsteamgenerator,SG-14.Table2shows~thegroupingsofindicationsutilizedtodeterminethegrowthdistribution.Figure1providestheBOC-14andEOC-14voltagedistributionresults.TheprobabilityoftubeburstundersteamlinebreakpressuredifferentialwascalculatedutilizingtheEPRIrecommendeddatabaseandtheNRCprovisionallyrecommendeddatabase(whichispendingreviewofEPRIproposals.)MedifferencesinthedatabasesareprimarilyassociatedwithEPRIrecommendationstoexcludehighburstpressureoutliers(D.C.Cook-1andKewaunee)fromtheburstcorrelation.TheprobabilityoftubeburstatEOC-14withtheEPRIrecommendeddatabaseis3.9x10',whiletheNRCrecommendeddatabaseprovidesaprobabilityofburstvalueof1.6x10'.BothvaluesarelessthantheaHowableSLBprobabilityofburstvalue2.5x10~,andthereforedemonstrateaccegtableresults.

Attachaient2toAEP:NRC:6IPage2Table1SG-14:SummaryofCook-1ROC-14SLBLeakRateAnalysisResultsSLBLeakRates(gym)LeakageROCVoltageDistributionBobbinwithPODAdjustment-LoglogisticPOL-LogisticPOL-LognormalPOL-NormalPOL-LogCauchyPOL-Cauchy=POLDraftNUREG-1477Method0.1100.6070.0450.4520.8531.360APCLeakRateCorrelation0.0010.0040.0010.0030.0050.008 Table21Cook1,ROC13,ComparisonofPIsFoundatTSPssConlirmedbyRPC,andIndicationsRepairedStcamGeneratorISteamGeneratoraSteamGenerator3StcamGenerator4AllSteamGeneratorsVolts000.10.20.30.10.5HsxofHo.ofBcbb4lodscadoastndiradoasExacatncd2214Ho.ofIndicarioosCoatirnsedHo.ofNo.ofHrxoflrafrcarionsBobbinIodiearioasRabedIndicadoasEcarsdncd1321Ho.oftndiearloas~dHo.ofNo.ofHo.of!OdicahonsBobbinlndicahoasRcpaircdindicationsExamined13NrxofIndicationConfirmedNrxofNrxofNo.ofIndicationsBobbintadicarioasRctalrcdIndicationExamined19No.oflndicaBolasConlinncdHo.ofNo.ofNo.ofIndicationsBobbinIadicarioaRepairedlndicahoasKxarasncd2061No.ofIndicationsConfirmcdHo.ofIndicanonsRcpaircd00itls1413270.70.9I.O1.21.32320131317IS1713176347311713131717131.6ISTorst1561031714931477lcToast>IV10IO1643AEPDATA'%3Tauri.lOottsVITAsaloftASIAre 4

504540FigureI:D.C.CookI,SG4,DistributionofTSPIndicationsPoDAdjustedBOCIndicationsProjectedtotheEndofCycle14ClBOC14Indications8ProjectedEOC14Indications~0Q)ft~08ts0~4O~o35<30O-25J3201510000000O00O0OClMWM000Ch3O0O000O0HHrIBobbinAmplitude(Volts)000Vl0000tAEPSIM93.XLS)INDDistRFK4/8/94,1:32PM