ML17331B354

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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 American Electric Power icon.png
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)


Text

ACCELERATED DISTRIBUTION DEMONSTRATION SYSTEM~~lREGULATORY INFORMATION DISTRIBUTION SYSTEM(RIDS)ACCESSXON NBR:9404210285 DOC.DATE:

94/04/18NOTARIZED:

NODOCKETFACIL:50-315 DonaldC.CookNuclearPowerPlant,Unit1,IndianaM05000315AUTH.NAMEAUTHORAFFILIATXON FITZPATRICK,E.

IndianaMichiganPowerCo.(formerly Indiana&MichiganEleRECIP.NAME RECIPIENT AFFILIATION DocumentControlBranch(Document ControlDesk)SUBZECT:ForwardsSGtubeinspections priortostartuprept.Attachment 1containsCategoryC-3rept,requiredbyTS4.4.5.5(c),including follow-up invests.gations

&subsequent repairsformed.DISTRIBUTION CODE:A001DCOPIESRECEIVED:LTR ENCLSIZE:TITLE:ORSubmittal:

GeneralDistribution DNOTES'ECIPIENT IDCODE/NAME PD3-1LAHICKMAN,Z COPIESRECIPIENT LTTRENCLIDCODE/NAME 11PD3-1PD22COPIESLTTRENCL11ADDINTERNAL:

NRR/DE/EELB NRR/DRCH/HICB NRR/DSSA/S PLBNUDOCS-ABSTRACT OGC/HDS2EXTERNAL:

NRCPDR111111111011NRR/DORS/OTSB NRR/DRPWNRR/DSSA/SRXB OC/LFDCB~~&G01NSIC111111101111DNOTETOALL"RIDS"RECIPIENTS:

PLEASEHELPUSTOREDUCEWASI'E!CONTACTTHEDOCUMENTCONTROLDESK,ROOMPl-37(EXT.20079)TOELIMINATE YOURNAMEFROMDISTRIBUTION LISTSFORDOCUMENTS YOUDON'TNEED!TOTALNUMBEROFCOPIESREQUIRED:

LTTR16ENCL14DD IndianaMichiganPowerCompanyP.O.Box16631Cofumbus, OH43216AEP:NRC:1166I DonaldC.CookNuclearPlantUnit1DocketNo.50-315LicenseNo.DPR-58STEAMGENERATOR TUBEINSPECTIONS PRIORTOSTARTUPREPORTU.S.NuclearRegulatory Commission DocumentControlDeskWashington, D.C.20555Attn:W.T.RussellApril18,1994

DearMr.Russell:

Pursuanttotherequirements ofDonaldC.CookNuclearPlantTechnical Specifications 4.4.5.5(c) and(e),thislettertransmits therequired"priortorestart"reportontheresultsofoureddycurrentinspection andsubsequent repairsperformed onthesteamgenerator tubesduringthe1994Unit1Refueling Outage.Attachment 1containstheCategoryC-3report,requiredbyT/S4.4.5.5(c),

including follow-up investigations andsubsequent repairsperformed.

Attachment 2containsthesteamline breakleakageanalysisrequiredbyT/S4.4.5.5(e) andprovidestheevaluation oftheprobability oftubeburstduringasteamline breakcommitted toinourletterAEP:NRC:1166M, datedFebruary14,1994.Sincerely, ud,~~E.E.Fitzpatrick VicePresident Attachments drcc:A.A.BlindG.CharnoffJ.B.Martin-RegionIIINFEMSectionChiefNRCResidentInspector J.R.Padgett9404210285 940018PDR,ADOCK0500031S.PDR ATTACHMENT 1TOAEP:NRC:1166I CATEGORYC-3REPORT Attachment 1toAEP:NRC:1166I Page1CATEGORYC-3INVESTIGATION TheresultsoftheCookNuclearPlantUnit1refueling outageeddycurrentinspections forbothbobbincoil.(BC) androtatingpancakecoil(RPC)tubesampleprogramswereprovidedtotheNRCinourletterAEP:NRC:11660, datedMarch30,1994.Theinspection resultedinaCategoryC-3classification, perTechnical Specification 4.4.5.5.Theprincipal reasonforthe.C-3classification wasthenumberofdefectsidentified atthehotlegtop-of-tubesheet regionbyRPCinspection.

Outsidediameterstresscorrosion ciacking(ODSCC)indications atthehotlegtopoftubesheet regionhashistorically beenanareaofconcernintheUnit1steamgenerators.

Reviewofthedatashowsamajorityoftheindications, approximately 888,tobebelowthetopoftubesheet inarangefromafewtenthsofaninchto2.25inches.Theremaining indications wereatorslightlyabovethetopoftubesheet inarangeof0.0inchesto0.7inches.AsaresultofthisRPCinspection, 237tubeswereplugged(asnotedinTable1ofAttachment 2ofAEP:NRC:11660).

Toassistindetermining thetrendinODSCC,the1992RPCdatawerereviewedusingthe1994analysisguidelines.

Thisreviewidentified thatapproximately 40%oftheindications werenewandthatthebalance.werepresentduringthe1992inspection.

TheRPCvoltagerangeforthema]orityoftheindications waslessthan0'volts.Ingeneral,theindications typically exhibited onlyslightchangesindepthand/orvolume.Thedatacollection duringthe1994inspection hadahighersignaltonoiseratioandahigherrotatingprobespeedthanin1992,makingtheindications morediscernible.

This,coupledwithmoreexperienced analystsandimprovedanalysisguidelines andtrainingassistedintheidentification oftheselowvoltageindications duringthe1994inspection.

Althoughitisapparentfromthe1994datathattubecorrosion hasnotcompletely stopped,itiscontinuing ataslow,manageable rate.InanefforttocombattheODSCCatthetopoftubesheet, anumberofadditional remedialmeasureswereemployedthis'efueling outage.Twonewprocesses wereaddedtothesteamgenerator secondary sidesludgeremovaloperations:

sludgeremovalwiththeConsolidated EdisonCombinedInspection andLancingSystem(CECIL)andPressurePulseCleaning(PPC).CECILprovidesthecapability toperformsludgeremovaldeepinthetubebundle,usingahighpressuresprayatobservedareasofhardsludgebuildup.PPCprovidestheabilitytoforciblysurgewaterthroughthetubesupportplateopeningsandalsocreatesturbulence atthetopoftubesheet whichaidsintheagitation andsoakingofcreviceregions.Thisisinadditionto,theprimaryoh)ective ofPPC,whichisremovalofsludgedepositsthroughout thesteamgenerator.

Remedialmeasureswhichwillremainineffectincludereactorcoolantsystemreducedpressureandtemperature operation, on-lineboricacidaddition, boricacidtubesheet creviceflushingduringstartup,tubesheet sludgeremoval,andimprovedsecondary sidechemistry.

~~

~~I~Attachment 1toAEP:NRC:1166I Page2The'994eddycurrentinspection resultswillbereviewedinfurtherdetailinthefollowing months,alongwithotheravailable industryexperience.

Thiswillbedonetodevelopanoverallassessment ofsteamgenerator tubeintegrity andtoassesstheneedforanychangestotheremedialmeasuresnowinplace,aswellastoaidinplanningforfuturetubeinspections.

ATTACHMENT 2TOAEP:NRC:1166I STEAMLINE BREAKLEAKAGEANALYSISANDPROBABILITY OFTUBEBURSTEVALUATION Attachment 2toAEP:NRC:1 66IPage1D.C.CookUnit1InterimPluggingCriteriaLetterReportThisreportprovidesasummaryandconclusions oftheleakrateandburstcalculations performed fortheD.C.CookUnit1interimpluggingcriteria.

Table1providesasummaryoftheD.C.Cook1projected EOC-14leakrateresults.SLBleakrateswerecalculated foratotaloftwelvecases,thecombination ofsixprobability-of-leak correlations andtwoleakratecalculation methodologies.

Thetwoleakratecalculations arethose'ndraftNUREG-1477 andaleakrateversusvoltagecorrelation (regression analysis).

Thismeetstherequirements oftheCook-1IPCSERrequirements.

TheNRCSERalsospecifies thattheanalysesaretobebasedonaleakageandburstdatabasethatexcludesoutliersonlyonthebasisofbaddata.ThisguidanceisfollowedfortheSERrequiredanalyses, althoughtheNRCSERdatabasediffersfromtheEPRIdatabaseinthetreatment ofoutliers, Insomecases,suchasthePOLcorrelations, thedifferences betweentheNRCandEPRIdatabases arenegligible.

Consistent withtheNRCguidanceoftheFebruary8,1994,NRC/Industry meeting,criteriaweredeveloped andusedtodeletenon-applicable data.TheSLBleakratesarecorrelated withvoltagewithinthestatistical confidence guidelines presented atthatmeeting.TheleakratesfortheAPCleakratecorrelation methodology areontheorderof100timeslowerthanthoseobtainedbytheNUREGcalculation, whichdoesnotconsiderthecorrelation.

Leakagecalculations werebasedonthecalculated EOC-14voltagedistribution determined byapplyingtheCycle13growthdistribution totheBOC-14indications, usingMonteCarlotechniques.

Thiswasperformed forthemorelimitingsteamgenerator, SG-14.Table2shows~thegroupings ofindications utilizedtodetermine thegrowthdistribution.

Figure1providestheBOC-14andEOC-14voltagedistribution results.Theprobability oftubeburstundersteamlinebreakpressuredifferential wascalculated utilizing theEPRIrecommended databaseandtheNRCprovisionally recommended database(whichispendingreviewofEPRIproposals.)

Medifferences inthedatabases areprimarily associated withEPRIrecommendations toexcludehighburstpressureoutliers(D.C.Cook-1andKewaunee) fromtheburstcorrelation.

Theprobability oftubeburstatEOC-14withtheEPRIrecommended databaseis3.9x10',whiletheNRCrecommended databaseprovidesaprobability ofburstvalueof1.6x10'.BothvaluesarelessthantheaHowableSLBprobability ofburstvalue2.5x10~,andtherefore demonstrate accegtable results.

Attachaient 2toAEP:NRC:6IPage2Table1SG-14:SummaryofCook-1ROC-14SLBLeakRateAnalysisResultsSLBLeakRates(gym)LeakageROCVoltageDistribution BobbinwithPODAdjustment

-LoglogisticPOL-LogisticPOL-LognormalPOL-NormalPOL-LogCauchyPOL-Cauchy=POLDraftNUREG-1477 Method0.1100.6070.0450.4520.8531.360APCLeakRateCorrelation 0.0010.0040.0010.0030.0050.008 Table21Cook1,ROC13,Comparison ofPIsFoundatTSPssConlirmed byRPC,andIndications RepairedStcamGenerator ISteamGenerator aSteamGenerator 3StcamGenerator 4AllSteamGenerators Volts000.10.20.30.10.5HsxofHo.ofBcbb4lodscadoas tndiradoas Exacatncd 2214Ho.ofIndicarioos Coatirnsed Ho.ofNo.ofHrxoflrafrcarions BobbinIodiearioas RabedIndicadoas Ecarsdncd 1321Ho.oftndiearloas

~dHo.ofNo.ofHo.of!Odicahons Bobbinlndicahoas Rcpaircdindications Examined13NrxofIndication Confirmed NrxofNrxofNo.ofIndications Bobbintadicarioas RctalrcdIndication Examined19No.oflndicaBolasConlinncd Ho.ofNo.ofNo.ofIndications BobbinIadicarioa Repairedlndicahoas Kxarasncd 2061No.ofIndications ConfirmcdHo.ofIndicanons Rcpaircd00itls1413270.70.9I.O1.21.32320131317IS1713176347311713131717131.6ISTorst1561031714931477lcToast>IV10IO1643AEPDATA'%3Tauri.lOottsVITAsaloftASIAre 4

504540FigureI:D.C.CookI,SG4,Distribution ofTSPIndications PoDAdjustedBOCIndications Projected totheEndofCycle14ClBOC14Indications 8Projected EOC14Indications

~0Q)ft~08ts0~4O~o35<30O-25J3201510000000O00O0OClMWM000Ch3O0O000O0HHrIBobbinAmplitude (Volts)000Vl0000tAEPSIM93.XLS)

INDDistRFK4/8/94,1:32PM