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{{#Wiki_filter:CATEGORYREGULATORYINFORMATIONDISTRIBUTIONSYSTEM"(RIDS)"4ACCESSIONNBR:9804200484DOC.DATE:98/04/14NOTARIZED:YESFACIL:50-315DonaldC.CookNuclearPowerPlant,Unit1,IndianaM50-316Donald.C.CookNuclearPowerPlant,Unit2,IndianaMAUTH;NAMEAUTHORAFFILIATIONFITZPATRICK,E.IndianaMichiganPowerCo.RECIP.NAMERECIPIENTAFFILIATIONDocumentControlBranch(DocumentControlDesk)DOCKET¹0500031505000316
{{#Wiki_filter:CATEGORYREGULATORY INFORMATION DISTRIBUTION SYSTEM"(RIDS)"
4ACCESSION NBR:9804200484 DOC.DATE:
98/04/14NOTARIZED:
YESFACIL:50-315 DonaldC.CookNuclearPowerPlant,Unit1,IndianaM50-316Donald.C.CookNuclearPowerPlant,Unit2,IndianaMAUTH;NAME AUTHORAFFILIATION FITZPATRICK,E.
IndianaMichiganPowerCo.RECIP.NAME RECIPIENT AFFILIATION DocumentControlBranch(Document ControlDesk)DOCKET¹0500031505000316


==SUBJECT:==
==SUBJECT:==
ForwardsresponsetoGL97-06,"DegradationofSGIntervals.DISTRIBUTIONCODE:ZOOIDCOPIESRECEIVED:,LTRiENCLiSIZE:TITLE:ORSubmittal:GeneralDistributionNOTES:RECIPIENTIDCODE/NAMEPD3-3LASTANG,JCOPIESLTTRENCL,1111RECIPIENTIDCODE/NAMEPD3-3PDCOPIESLTTRENCL11EINTERNAL.-ENT---1NRR/DE/EMCBNRR/DSSA/SPLBNUDOCS-ABSTRACTEXTERNAL:NOAC11111111NRR/DE/ECGB/ANRR/DRCH/HICBNRR/DSSA/SRXBOGC/HDS2NRCPDR1111111011DNOTETOALL"RIDS"RECIPIENTS:PLEASEHELPUSTOREDUCEWASTE.TOHAVEYOURNAMEORORGANIZATIONREMOVEDFROMDISTRIBUTIONLISTSORREDUCETHENUMBEROFCOPIESRECEIVEDBYYOUORYOURORGANIZATION,CONTACTTHEDOCUMENTCONTROLDESK(DCD)ONEXTENSION415-2083TOTALNUMBEROFCOPIESREQUIRED:LTTR13ENCL12 IndianaMichigan~PowerCompany500CircleDriveBuchanan,Ml491071395IlfNENANAMICHIGANPQWMApril14,1998AEP:NRC:1166AMDocketNos.:50-31550-316U.S.NuclearRegulatoryCommissionATTN:DocumentControlDeskMailStop0-Pl-17Washington,D.C.20555-0001Gentlemen:DonaldC.CookNuclearPlantUnits1and2RESPONSETONRCGENERICLETTER(GL)97-06DEGRADATIONOFSTEAMGENERATORINTERNALSThisletteranditsattachmentprovideinformationrequestedinGL97-06,concerningsteamgeneratorinternalsdegradation.Sincerely,pugE.E.FitzpatrickVicePresidentJ'SWORNTOANDSUBSCRIBEDBEFOREMEgATHIS~DAYOF~/Z.,1998NotaryPublic/.Sd//vlbAttachmentZ.A.AbramsonA.B.BeachMDEQ-DW&RPDNRCResidentInspector8.R.SampsonUNDALBOEI.CKENotaryPublic,BerrienCounty,MlMCommissionExpiresJanuary21,200I2001yQoI98042004849804l4PDRADOCK050003iSpPDR ATTACHMENTTOAEP:NRC:1166AMRESPONSETONRCGENERICLETTER97-06DEGRADATIONOFSTEAMGENERATORINTERNALS 5.~'AttachmenttoAEP:NRC:1166AMPage1INTRODUCTIONGenericletter(GL)97-06wasissuedto'alertaddresseestoforeignanddomesticfindingsofdamagetosteamgenerator(SG)internals,emphasizetheimportanceofperformingcomprehensiveexaminationsofSGinternals,andrequestinformationthatwillenabletheNRCstafftoverifytheinternalsofCookNuclearPlant'sSGsconform-tothecurrentlicensingbasis.BACKGROUNDANDDESCRIPTIONOFCIRCUMSTANCESFrenchauthoritieshavereportedvariousSGtubesupportplate(TSP)damagemechanisms.Damagehas.-includedwastageintheuppermostTSPduetomisapplicationof.achemicalcleaningprocess,brokenTSPligamentsresultingfrominadequateclearancefor,differentialthermalexpansion,andTSPwastageatvariouselevationsapparentlyinvolvingacorrosionorerosion-corrosionmechanismofundeterminedorigin.Otherins'tancesofinternalsdegradationincludewrapperdrop/crackingataforeignutilitythatissuspectedtohavebeencausedbyseverecoolingtransients,andinstancesoferosion-corrosionofeggcratesupportsinuntubedareasinitiated"byunknowncausesthatoccurredatadomesticfacility.Theseinstances.highlightthepotentialfordegradationmechanismsthatmayleadtoTSPandtubewrapperdamage..Asaresultofthisconcern,GL97-06requests:1.DiscussionofanyprogramsinplacetodetectdegradationofSGinternalsandadescriptionofinspectionplans(scope,frequency,methods,andequipment).Thisdiscussionshould.address.thefollowinginformationforeachfacility.a~b.C.WhetherinspectionrecordshavebeenreviewedforindicationsofTSPsignalanomaliesfromeddycurrenttestingofSGtubes'hatmaybeindicativeofsupportplateorligamentdamage.WhethervisualorvideocamerainspectionshavebeenperformedonthesecondarysidetogaininformationontheconditionofSGinternals(e.g.,supportplates,tubebundlewrappers,etc.).Whetherdegradation,ofSGinternalshasbeendetected,andhowitwasassessedanddispositioned.2.Intheeventnoprogramisinplacetodetectinternalsdegradation,provideadiscussionorjustificationfordevelopmentofaprogramorwhysuchaprogramisnot:needed..PriortoissuanceofthisGL,WestinghouseOwnersGroup(WOG),ElectricPowerResearchInstitute(EPRI),andNuclearEnergyInstitute(NEI)developedanactionplantoassessthesusceptibilityofSGsecondary"sidedegradation.Weintendtofollowtheindustryactionplanasmodifiedbyoursite-specificexperience.IncludedintheactionplanisarequirementtounderstandthecausalfactorsinvolvedinthedegradationexperiencedintheFrenchunits.ThisinformationiscapturedinEPRIreportGC-109558,"SteamGeneratorInternalsDegradation:
ForwardsresponsetoGL97-06,"Degradation ofSGIntervals.
AttachmenttoAEP:NRC:1166AMPage2ModesofDegradationDetectedinEdFUnits".Thisreportwassubmitted'otheNRCviaanNEZletter,datedDecember19,1997.-WOGhasreviewedEPRZGC-109558relativetothe,designofseries51SGsanddeterminedlimitedpotentialsusceptibility.Forplantswithseries51SGs,thisconclusionisdocumentedinWCAP-15002,revision1,."EvaluationofEdFSteamGeneratorInternalsDegradation-ImpactofCausalFactorsonWestinghouse.51SeriesSteamGenerators",December1997.Theseries51SGsarethemostsimilarmodelSGtothatoftheElectricithdeFrance(EdF).unitsandareinstalledinunit1.WCAP-.15002,revision1,documentsvisualinspectionsperformedattheseries51SGplants.Ztwasconcluded.thatthenumber.ofplantsthathavebeeninspectedandtheinspectionresultsdemonstratethatthecausalfactorsidentifiedbyEdFdonotjeopardizethecontinuedoperabilityofWestinghouseseries51SGs.Thisconclusionissupportedbythe-capabilityofeddycurrentinspectionsto,detect.detrimentaleffectsontubingduetowearcausedbyTSPligamentdegradation,loose'parts,andsecondaryside'lowdistributionchanges.Foreignobjectsearchandretrieval~effortsaretypicallyconductedasstandardpracticetodiscoveror~retrievelooseparts,thuslimitingthepotentialfordamage.AresponsetoGL97-06hasbeencompletedforunit1addressingthesusceptibilityoftheunit1SGstointernalsdegradation,specificunit1inspectionpracticesandrecentinspectionresults,along,withadiscussionofsubsequentplantoperationwithpotentialSGinternalsdegradationofthetypeexperienced;intheFrenchunits(andothertypesofdegradationexperienceddomestically)~Thisdiscussionbeginsinthe"UNIT1SGPROGRAM(INTERNALS1NSPECTION)"sectionofthisattachment.BecauseadetailedWestinghouseevaluationhasnotbeenperformed,forourunit2SGs,inspectionrecommendationshave.beenidentifiedonaninterimbasis.Industryrepresentativeshaveindicatedthat'valuationsshouldbecompletedbyMay1998,andtheresultswillbefactoredintotheunit2SGprogram.Assuch.theresponseto'tem1forunit,2,whichisdetailedinthe"UNIT2SGPROGRAM(INTERNALSINSPECTION)"sectionofthisattachment,maybemodifiedinthefutureasdictatedbytheresultsofthependingevaluation.UNIT1SGPROGRAMINTERNALSINSPECTIONSGDescritionUnit1containsfourWestinghouseseries51SGsthatwereplacedinservicein1975.Keydesignfeaturesincludealloy600millannealedtubing,apartialdepthhardrollexpansionatthetube-to-tubesheetjoint,anddrilledcarbonsteelsupportplates.Thenominaltubeoutsidediameter(OD)is0.875incheswithanominalwallthicknessof0.050inches.Thefourunit1SGsarepresentlyscheduledforreplacementintheyear2000.
DISTRIBUTION CODE:ZOOIDCOPIESRECEIVED:,LTR iENCLiSIZE:TITLE:ORSubmittal:
Attachmentto=AEP:NRC:1166AMPage3RelatedIndustFindinsAsdiscussedinWCAP-15002,revision1,eighteenplantswithseries51SGssuppliedinformationtotheWOGconcerningresultsofSGsecondarysideinspectionsandrelevanttubeinspectionsforTSPconditions.TheseresultsdidnotreportdetectionofseveralmodesofdegradationexperiencedintheEdFunits.Thereis-noevidenceofpost-chemicalcleaninginspectionsindicatingany.significantmaterialloss,noristhereevidenceofwrapperhavingdropped.WhileTSPligamentcrackinghasoccurredinunitswithcarbonsteelsupport,plateswithdrilled'oundholesand.flow'oles,thereisnoevidenceindicatingTSPligamentcrackingorthinningthatisprogressiveandcontinuing.ThefollowingtablesummarizestheapplicableWOGconclusionsconcerningthesusceptibilityofSGslikeouiunit1series51SGstosecondarysideinternalsdegradation.TABLE1DEGRADATIONTYPEErosionCorrosion:MoistureSeparatorTSPFlowHole/LigamentsFeedRing/8-TubesCracking:TSPLigamentsNearWedges**TSPLigamentsNearPatchPlatesCarbonSteelTSPLigaments(randomareas)LEVELOFSUSCEPTIBILITYNNX*"Other:WrapperNearSupports**NWrapperDrop**NX~oservexnsomeSGsN=notsusceptibletoEdFcasualfactorsL~lowsusceptibilitytoEdFcasualfactors*~variousindicationofdegradationmaybeartifactsofmanufacturingrelatedtopatchplateplugweldsand/ordrillingalignment**variousWestinghousedesignfeatures'rebeneficialrelativetosomeoftheSGdesignfeaturesofforeignmanufacturersSite-SecificFindinsTheunit1SGswerelastinspectedinthespringof1997.In~additiontothestandardeddycurrenttubeinspection,additionalmeasureswereperformedtoassuretheintegrityoftheSGinternals.Theseinspections,coupledwithrelatedfindingsfrompreviousinspections,demonstratethatthe'reasnotedintable1havebeenperiodicallyexaminedwithnoabnormalconditions.noted.
GeneralDistribution NOTES:RECIPIENT IDCODE/NAME PD3-3LASTANG,JCOPIESLTTRENCL,1111RECIPIENT IDCODE/NAME PD3-3PDCOPIESLTTRENCL11EINTERNAL.-ENT---1NRR/DE/EMCB NRR/DSSA/SPLB NUDOCS-ABSTRACT EXTERNAL:
et~~AttachmenttoAEP:NRC:1166AMPage4Thefollowingdiscussionpresentstheinternalsinspectionscopeandfindingsfortheunit11997refuelingoutage(U1R97).A100%computerdatascreening(CDS)sortwasperformedonthelowfrequencybobbincoildatafromeachSGtoaddressthepotentialforTSPdamageorligamentcracking.Indicationsofpossibleligamentdamagewereexaminedusingamotorizedrotatingpancakecoil(MRPC)probe.Theindicationsweresubsequentlydispositionedashavingnodegradationfound(NDF)ordeterminedtobealignedwiththepatchplate,thusyieldinga"false"indication.Onetube,R39/C22inSG11wasnotedtohavea0.78'oltMRPCindicationattheseventhhotlegsupportplate,nearthewedgelocation.Researchofthepreviousoutagedataconfirmedthisconditionhasbeenpresentforatleastthreeyears.Thisindicationwillcontinuetobemonitoredduringfutureeddycurrentinspections.Regardingtheperformanceofsecondarysidevisualinspections,thefollowingactivitieswereperformedineachSG(unlessotherwisenoted)duringtheU1R97foreignobjectsearchandretrievaloperations:~Pre-SludgeLanceInspection-Avisualinspectionwasperformedtoidentifythetubing/sludgeconditionsatthetubesheetprior,tolancing.Thisinspectionincludedtheannulusanddividerlane.~Post-LanceInspection-Avisualinspectionwasperformedtoverifytheeffectivenessofthesludgeremovalprocessandgeneraltubesheet/tubingconditionsatthetopofthetubesheet.Theinspectionconsistedoftheannulus,dividerlaneandaninnerbundlepassinboththehotandcoldlegsides..WrapperBarrelInspection-Thisvisualinspectionwasperformedto.verifytheintegrityofthewrapperbarrelsupportstructure.FirstTubeSupportLigament(2,SGs)-ThisinspectioninvolvedavisualreviewofthefirstTSPbetweenthewrapperbarrelandthetubebundledirectlyabovethehandhold:Thepre/post-lanceinspectionsconfirmed"theeffectivenessofthesludgeremovaloperationsandthegeneralconditionofthetubingatthetubesheet.Noanomaliesorloosepartswerenotedbytheinspection.Thewrapperbarrelinspectionproducednoevidenceofslippageormovement.Additionalverificationoftheintegrityofthesupportstructurewasprovidedbythesuccessfulinstallationofthesludgelanceequipment.Thelackofanyinterferences'uringthisinstallationprovidedassurancethatnodeformationhad~occurred.InspectionsofthefirstsupportplateidentifiednosignsofanomaliesineitherofthetwoSGsinspected.WhilenoinspectionswereperformedduringU1R97ontheupperinternals,previousinspectionshaveidentifiedonlyminimalwear.'uringthe1995inspection,fifteenJ-nozzlesandthefeedringteesectionofoneSG.wereinspected.TheJ-nozzlesweretermedtobeinverygoodcondition,withnothinningobservedonthethermallinerandtee.Priortothe1995inspection,extensiveinspectionswereconductedin1989inwhichvisualinspectionswereconducted.ontheJ-nozzlesofthreeSGs.Thevisualexaminationofoneof l~
NOAC11111111NRR/DE/ECGB/A NRR/DRCH/HICB NRR/DSSA/SRXB OGC/HDS2NRCPDR1111111011DNOTETOALL"RIDS"RECIPIENTS:
AttachmenttoAEP:NRC:1166AMPage5theseSGswassupplementedbyanaddedultrasonictest(UT)examination.NeitherthevisualorUTexaminationsnotedanyapparentdegradation.Theseinspectionshaveindicatedthatdegradationintheupperinternalsisaslowprogressingphenomena.BasedonminimaldegradationtodateandthenearendoflifefortheseSGs,noexaminationswereperformedduringU1R97.SafetAssessmentThefollowingsafetyconcernshavebeenpostulatedbyWOGrelativetotheFrenchSGinternalsdegradationexperience.~Lossofsupportinthetube.bundleleadingtowear,andpossibleprimary-to-secondaryleakageorinadequateburstmargins.IncreasedTSPdeformationduringapostulatedloss-of-coolantaccident(LOCA)plussafeshutdownearthquake(SSE)'event,resultinginunacceptableSGtubecollapseorsecondary-to-primaryinleakage.i~GenerationofalooseobjectinthesecondarysideofaSGthatmayresultintubewearorimpacting,andpossiblyprimary-to-secondaryleakage.Asdiscussedbelow,industryexperienceandvariousstandardpracticesaretypicallyemployedtoprovideassuranceofSGintegrityandnegatethepotentialforthese'oncerns.AsevidencedfromthepreviouslydiscussedU1R97inspectionresults,ourunit1experiencesandpracticesmirrorthatoftheindustry.Basedon'reviewofthetable1information,theonlydegradationtypesthatmayoccurdomesticallythatcouldresult,inthelossofTSPintegrityareTSPflowhole/ligamenterosion-corrosion,TSPligamentcrackingnearthepatchplates,andTSPligamentcrackinginrandomareas.Thereisnoindustryevidenceofpost-chemicalcleaninginspectionsindicating.significantmaterialloss,noris'thereevidenceofanywrapperhavingdropped.WhileTSP'ligamentcrackinghasoccurredinunitswithcarbonsteel.supportplateswithdrilledroundholesandflowholes,thereisnoevidenceindicatingTSPligamentcrackingorthinningthatisprogressiveandcontinuing.Utilitieswithseries51SGswithcarbon'steelsupportplatesinspectasignificantpercentageofSGtubeseveryoutagewithabobbincoilprobe(unit1inspects100%).Ifsectionsofthetubesupportweremissing,itwouldbereadilydetectablebecauseofalackofeddycurrent.responseattheTSPelevation.Thereisnoincreasedsusceptibilitytoligamentcrackingnearthewedgesupportsintheseries51SGdesign.Eithertherearenoflowholesextendingtotheperiphery'atthewedgelocations,or=.thewedgesarenotweldedtotheTSPs,asisthecasewiththeEdF51MSG.ExistingcalculationsevaluatingtheeffectsofLOCAplusSSEloadingsonthetubebundlecontinuetoapplyindeterminingwhethercertaintubesshouldbeexcludedfromapplicationofthevoltagebasedpluggingcriteria,orwhethercertaintubesshouldberemovedfromserviceinplantsthatdonotcurrentlyhavethecriteria,butmayhaveSGtubesexperiencing~crackingatTSPintersections.
PLEASEHELPUSTOREDUCEWASTE.TOHAVEYOURNAMEORORGANIZATION REMOVEDFROMDISTRIBUTION LISTSORREDUCETHENUMBEROFCOPIESRECEIVEDBYYOUORYOURORGANIZATION, CONTACTTHEDOCUMENTCONTROLDESK(DCD)ONEXTENSION 415-2083TOTALNUMBEROFCOPIESREQUIRED:
AttachmenttoAEP:NRC:1166AMPage6AnotheroccurrenceresultingfromSGinternaldegradationthatmay.affectaSGinperformingitsintendedsafetyfunctionisthepotentialfortubewearandprimary-tosecondaryleakageduetothegenerationofalooseobjectonthesecondarysideoftheSG.Thismayoccurduetoerosion-corrosionofthemoistureseparators,feedring/J-nozzle,orTSPflowholes,ortheoccurrenceofTSPligamentcracking.Ifprimary-to-secondaryleakageshouldoccurbecauseoftubewearfromalooseobject,theexpectedconsequenceswouldbeboundedbyasingletuberuptureeventand,therefore,wouldremainwithinthecurrentlicensingbasisoftheplant.Itisourpositionthatlooseobjectsshouldberemovedwheneverpossible.Tubesobservedtohavevisibledamageareeddycurrentinspectedandpluggedasnecessary.ElementsoftheSGprogram,includi'ngeddycurrentinspection,foreignobjectsearchandretrievalduringeachrefuelingoutage,andloosepartsmonitoringareinplacetohelpensurethemaintenanceoftubeintegrityduringplantoperation.Becausenointernalsdegradationofconsequencehasbe'enobservedontheunit1SGs,itisexpectedthat,neartermdegradationwouldbelimitedinextent,suchthat'thetubeswillremaincapableofsustainingtheconditionsofnormaloperations,includingoperationaltransient,designbasisaccidents,externalevents,andnaturalphenomena,permittingtheaffectedSGtoperformitssafetyfunction.InserviceInsectionPlanBecauseof.thependingSGreplacement,itisprojectedthattheunit1SGswillundergoonlyonemoreinspectionpriortothereplacementoutage.Basedonthepreviousdiscussions,theupcominginspectionplanwillcloselymirroractivitiesperformedin1997.Theplannedworkscopeissummarizedasfollows.A100%CDSscanwillbeperformedonthebobbincoildatafor.evidenceofsupportplate/ligamentdamage.IndicationdispositionwillbebyMRPCprobe.Notethatthebobbincoilexaminationwillbeperformedon100%ofthein-servicetubing.ForeignobjectsearchandretrievaloperationswillbeperformedineachSGtoaccessthetubingandsupportstructureconditionsaswellasverifythesludgeconditionswithintheSGs.Accessibletubesheetsurfacesandtubesatthetopofthetubesheetwillbetargetedduringtheinspection.DuringsludgelanceoperationstobeperformedineachSG,itwillbeverifiedthatthelancingequipmentcanbeinsertedwithoutinterference.Successfulinstallationwillprovideverificationofwrapperintegri.ty.Ifinterferenceisdetected,thelowerwrappersupportblockswillbevisuallyinspected.Thewrapperblock'inspectionwillalsobeconductedifanyevidenceoftubedamageintheperipheryofthefirstTSPisdetected.InspectionswillbeperformedonthefirstanduppermostTSPofoneSGtoassessfoulingconditionsandidentifyanyevidenceofcorrosionordamage.  
LTTR13ENCL12 IndianaMichigan~PowerCompany500CircleDriveBuchanan, Ml491071395 IlfNENANAMICHIGANPQWMApril14,1998AEP:NRC:1166AM DocketNos.:50-31550-316U.S.NuclearRegulatory Commission ATTN:DocumentControlDeskMailStop0-Pl-17Washington, D.C.20555-0001 Gentlemen:
~~AttachmenttoAEP:NRC:1166AMPage7Basedonsiteinspectionexperience,noupper-bundleinspectionsareplannedduringtheupcominginspection.Shouldtheunit.1SGsbereplacedduringthenextoutage,ourinspectionplanwillberevisedappropriately.-UNIT2SGPROGRAMINTERNALSINSPECTIONSGDescritionIn1989,thefouroriginalunit2Westinghouseseries53.SGswerereplacedwithWestinghouseseries54FSGs.KeydesignfeaturesofthereplacementSGs.includethermallytreatedalloy690tubing,afulldepthhydraulicexpansionatthetube-to-tubesheet'joint,quatrefoilstainlesssteelsupportplates,.increasedrow1U-bendradius,andheattreatedlowrowU-bends.ThenominaltubeODis0.875inches,withanominalwallthicknessof0.050inches.RelatedIndustrFindinsAsdiscussedinWCAP-15002,revision1,twelveplantswithseriesD,E,44F,andFSGssuppliedinformationtotheWOGconcerningresultsofSGsecondarysideinspectionsandrelevanttubeinspectionsforTSPconditions.Forthemost,part,thefindingsdidnotreportdetectionofseveralmodesofdegradationexperiencedintheEdFunits.Thereisnoevidenceofpost-chemicalcleaninginspectionsindicatingsignificantmaterialloss,.noristhereevidenceofanywrapper,havingdropped.WhileTSPligamentcrackinghasoccurredinunitswithcarbonsteelsupportplateswithdrilledroundholesandflowholes,thereisnoevidenceindicatingTSPligamentcrackingorthinningthatisprogressiveandcontinuing.ThefollowingtablesummarizestheapplicableWOGconclusionsconcerningthesusceptibilityofSGsliketheunit2series54FSGs.tosecondarysideinternalsdegradation.TABLE2DEGRADATIONTYPELEVELOFSUSCEPTIBILITYErosionCorrosion:MoistureSeparatorTSPFlowHole/LigamentsFeedRing/8-NozzlesCracking:TSPLigaments***WrapperNearSupports*+Other:NAWrapperDrop**
DonaldC.CookNuclearPlantUnits1and2RESPONSETONRCGENERICLETTER(GL)97-06DEGRADATION OFSTEAMGENERATOR INTERNALS Thisletteranditsattachment provideinformation requested inGL97-06,concerning steamgenerator internals degradation.
AttachmenttoAEP:NRC:1166AMPage8XLNA~*aobservedinsomeSGslowsusceptibilitynotapplicablevariousindicationofdegradationmaybeartifactsofmanufacturingrelatedtopatchplateplugweldsand/ordrillingalignmentvariousWestinghouse.designfeatures'arebeneficialrelativetosomeoftheSGdesignfeaturesofforeignmanufacturersSite-SecificFindinsTheunit2SGswerelastinspectedinthefallof1997.Inadditiontothestandardeddy"currenttubei.nspection,othermeasureswereperformedtoassuretheintegrityoftheSGinternals.Theseinspections,coupledwithrelatedfindingsfrom'reviousinspectionsanddesignattributesoftheunit2series54FSGs,demonstrate.,thattheareasofinterestas,noted"intable2havebeenaddressedwithnoabnormalconditionsnoted.Thefollowingdiscussionpresentstheinternalsinspectionscopeandfindingsfortheunit21997refuelingoutage(U2R97).ThefollowingactivitieswereperformedineachSG(unlessotherwisenoted)duringtheU2R97foreignobjectsearchandretrievaloperations.~Pre-sludgeLanceInspection-Avisualinspectionwasperformedtoidentifythetubing/sludge,conditionsatthetubesheetpriortolancing.Thisinspectionincludedtheannulusanddividerlane.Post-LanceInspection-Avisualinspectionwasperformedtoverifytheeffectivenessofthesludgeremovalprocessandthegeneraltubesheet/tubingconditionsonthetopofthetubesheet.Areasreviewedconsistedoftheannulus,dividerlaneandaninnerbundlepass.onboththehot.andcoldlegsides.~Sixthand'SeventhTSP.(OneSG)-AvisualinspectionreviewedthesixthandseventhTSPstoaccesssludgeconditionsandfoulingconditionsintheupperregionoftheoneSG.Thepre/post-lanceinspectionconfirmedtheeffectivenessofthesludgeremovaloperationsandthegeneralconditionofthetubingat'hetubesheet.No,,degradationorsignsofabnormalitieswerenotedduringtheinspection.Theuppersupportplateinspectionnotednosignsofdamagedcomponentsordegradation.RegardingTSPdamage.orligamentcracking,eddycurrentassessmentswerenotperformedbecausethequatrefoilbroachedholesupportplatedesignmakesthistechniquenotapplicablefordetectingdamage.Noabnormalitiesweredetectedinthisareaduringtheforeignobjectsearchandretrievaloperationsthatwouldsuggestdamageofthisnature.Ingeneral,erosion-corrosioninduceddegradationisviewedasalowsusceptibilityeventbecausetheplatesareconstructedofstainlesssteel.Specificinspectionofthewrapperbarrelareawasnotperformed.However,wrapperconditionsdidnotaffecttheinstallationofthe AttachmenttoAEP:NRC:1166AMPage9sludgelancingequipmentthatwasperformedineachSG.Therefore,itwasconcludedthatthewrapperhadnotslippedormoved.WhilenoinspectionswereperformedduiingU2R97,on,theupperinternals,previousinspectionshavebeenperformed.Duringthe1994inspection,tenJ-nozzlesandthefeedringteesectionofoneSGwereinspected.Noerosionwasnotedduringtheinspection.Theoriginal,feedrings/J-nozzleswerereplacedwhentheunit2SGswerereplacedin1989.ThereplacementfeedringsareconstructedofextrastrongcarbonsteelandtheJ-nozzlesaremade.from,alloy600,whichislesssusceptibletoerosiondamagethan.thetypicalcarbonsteelJ-nozzles.Theseinspectionsindicatethatdegradationintheupperinternalsisaslowprogressingphenomena.,Basedonminimaldegradationto-date,noexaminationswerescheduled'forU2R97.SafetAssessmentAsnotedintheunit1safetyassessment,thefollowingsafetyconcernshavebeenpostulatedbytheWOGrelativetotheFrenchSGinternalsdegradationexperience.~>>Lossofsupportleadingtowearandpossibleprimary-to-secondaryleakageorinadequateburstmargins..MoresignificantTSPdeformationduringapostulatedLOCAplusSSEevent,resultinginunacceptableSGtubecollapseorsecondary-to-primaryinleakage.GenerationofalooseobjectinthesecondarysideofaSGwhichmayresultintubewearorimpactingandpossiblyprimary-to-secondaryleakage.Asdiscussedbelow,design.features,industryexperience,andvariousstandardpracticesaretypicallyemployedto-provideassuranceofSGintegrityandnegatethepotentialfortheseconcerns.PreviouslydiscussedU2R97inspectionresultsindicateourunit2experiencesandpracticesaresimilartothatoftheindustry.Basedonareviewofthetable2information,theonlydegradationtypesthatmayoccurdomesticallythatwouldlikelyresultinthelossofTSPintegrityareTSPflowhole/ligamenterosion-corrosion,TSPligamentcrackingnearthepatchplates,andTSPligamentcrackinginrandomareas.Thereisnoindustryevidenceofpost-chemicalcleaninginspectionsresultinginthediscoveryofanysignificantmaterialloss,noristhere.evidenceofanywrapperhavingdropped.NoTSPligamentindicationshavebeenfoundinsteamgeneratorswithstainlesssteelTSPs.Thispopulationincludestheunit2SGs.NoincreasedsusceptibilitytoligamentcrackingnearthewedgesupportshasbeenidentifiedintheseriesD,E,44F,andF(unit.2)SGsdesigns.ExistingcalculationsevaluatingtheeffectsofLOCAplusSSEloadingsonthetubebundlecontinuetoapplyindeterminingwhethercertaintubesshouldbeexcludedfromapplicationofthevoltagebasedpluggingcriteria,orwhethercertain.tubesshouldberemovedfromserviceinplantsthatdonotcurrentlyhaveacriteriabutmayhaveSGtubesexperiencingcrackingatTSPintersections.  
Sincerely, pugE.E.Fitzpatrick VicePresident J'SWORNTOANDSUBSCRIBED BEFOREMEgATHIS~DAYOF~/Z.,1998NotaryPublic/.Sd//vlbAttachment Z.A.AbramsonA.B.BeachMDEQ-DW&RPDNRCResidentInspector 8.R.SampsonUNDALBOEI.CKENotaryPublic,BerrienCounty,MlMCommission ExpiresJanuary21,200I2001yQoI9804200484 9804l4PDRADOCK050003iSpPDR ATTACHMENT TOAEP:NRC:1166AMRESPONSETONRCGENERICLETTER97-06DEGRADATION OFSTEAMGENERATOR INTERNALS 5.~'Attachment toAEP:NRC:1166AM Page1INTRODUCTION Genericletter(GL)97-06wasissuedto'alertaddressees toforeignanddomesticfindingsofdamagetosteamgenerator (SG)internals, emphasize theimportance ofperforming comprehensive examinations ofSGinternals, andrequestinformation thatwillenabletheNRCstafftoverifytheinternals ofCookNuclearPlant'sSGsconform-tothecurrentlicensing basis.BACKGROUND ANDDESCRIPTION OFCIRCUMSTANCES Frenchauthorities havereportedvariousSGtubesupportplate(TSP)damagemechanisms.
Damagehas.-includedwastageintheuppermost TSPduetomisapplication of.achemicalcleaningprocess,brokenTSPligaments resulting frominadequate clearance for,differential thermalexpansion, andTSPwastageatvariouselevations apparently involving acorrosion orerosion-corrosion mechanism ofundetermined origin.Otherins'tances ofinternals degradation includewrapperdrop/cracking ataforeignutilitythatissuspected tohavebeencausedbyseverecoolingtransients, andinstances oferosion-corrosion ofeggcratesupportsinuntubedareasinitiated "byunknowncausesthatoccurredatadomesticfacility.
Theseinstances.
highlight thepotential fordegradation mechanisms thatmayleadtoTSPandtubewrapperdamage..Asaresultofthisconcern,GL97-06requests:
1.Discussion ofanyprogramsinplacetodetectdegradation ofSGinternals andadescription ofinspection plans(scope,frequency, methods,andequipment)
.Thisdiscussion should.address.thefollowing information foreachfacility.
a~b.C.Whetherinspection recordshavebeenreviewedforindications ofTSPsignalanomalies fromeddycurrenttestingofSGtubes'hat maybeindicative ofsupportplateorligamentdamage.Whethervisualorvideocamerainspections havebeenperformed onthesecondary sidetogaininformation onthecondition ofSGinternals (e.g.,supportplates,tubebundlewrappers, etc.).Whetherdegradation, ofSGinternals hasbeendetected, andhowitwasassessedanddispositioned.
2.Intheeventnoprogramisinplacetodetectinternals degradation, provideadiscussion orjustification fordevelopment ofaprogramorwhysuchaprogramisnot:needed..
PriortoissuanceofthisGL,Westinghouse OwnersGroup(WOG),ElectricPowerResearchInstitute (EPRI),andNuclearEnergyInstitute (NEI)developed anactionplantoassessthesusceptibility ofSGsecondary "sidedegradation.
Weintendtofollowtheindustryactionplanasmodifiedbyoursite-specific experience.
Includedintheactionplanisarequirement tounderstand thecausalfactorsinvolvedinthedegradation experienced intheFrenchunits.Thisinformation iscapturedinEPRIreportGC-109558, "SteamGenerator Internals Degradation:
Attachment toAEP:NRC:1166AM Page2ModesofDegradation DetectedinEdFUnits".Thisreportwassubmitted'o theNRCviaanNEZletter,datedDecember19,1997.-WOGhasreviewedEPRZGC-109558 relativetothe,designofseries51SGsanddetermined limitedpotential susceptibility.
Forplantswithseries51SGs,thisconclusion isdocumented inWCAP-15002, revision1,."Evaluation ofEdFSteamGenerator Internals Degradation
-ImpactofCausalFactorsonWestinghouse
.51SeriesSteamGenerators",
December1997.Theseries51SGsarethemostsimilarmodelSGtothatoftheElectricith deFrance(EdF).unitsandareinstalled inunit1.WCAP-.15002, revision1,documents visualinspections performed attheseries51SGplants.Ztwasconcluded
.thatthenumber.ofplantsthathavebeeninspected andtheinspection resultsdemonstrate thatthecausalfactorsidentified byEdFdonotjeopardize thecontinued operability ofWestinghouse series51SGs.Thisconclusion issupported bythe-capability ofeddycurrentinspections to,detect.
detrimental effectsontubingduetowearcausedbyTSPligamentdegradation, loose'parts, andsecondary side'lowdistribution changes.Foreignobjectsearchandretrieval
~effortsaretypically conducted asstandardpracticetodiscoveror~retrievelooseparts,thuslimitingthepotential fordamage.AresponsetoGL97-06hasbeencompleted forunit1addressing thesusceptibility oftheunit1SGstointernals degradation, specificunit1inspection practices andrecentinspection results,along,withadiscussion ofsubsequent plantoperation withpotential SGinternals degradation ofthetypeexperienced;in theFrenchunits(andothertypesofdegradation experienced domestically)
~Thisdiscussion beginsinthe"UNIT1SGPROGRAM(INTERNALS 1NSPECTION)
"sectionofthisattachment.
BecauseadetailedWestinghouse evaluation hasnotbeenperformed
,forourunit2SGs,inspection recommendations have.beenidentified onaninterimbasis.Industryrepresentatives haveindicated that'valuations shouldbecompleted byMay1998,andtheresultswillbefactoredintotheunit2SGprogram.Assuch.theresponseto'tem1forunit,2,whichisdetailedinthe"UNIT2SGPROGRAM(INTERNALS INSPECTION)"
sectionofthisattachment, maybemodifiedinthefutureasdictatedbytheresultsofthependingevaluation.
UNIT1SGPROGRAMINTERNALS INSPECTION SGDescritionUnit1containsfourWestinghouse series51SGsthatwereplacedinservicein1975.Keydesignfeaturesincludealloy600millannealedtubing,apartialdepthhardrollexpansion atthetube-to-tubesheet joint,anddrilledcarbonsteelsupportplates.Thenominaltubeoutsidediameter(OD)is0.875incheswithanominalwallthickness of0.050inches.Thefourunit1SGsarepresently scheduled forreplacement intheyear2000.
Attachment to=AEP:NRC:1166AMPage3RelatedIndustFindinsAsdiscussed inWCAP-15002, revision1,eighteenplantswithseries51SGssuppliedinformation totheWOGconcerning resultsofSGsecondary sideinspections andrelevanttubeinspections forTSPconditions.
Theseresultsdidnotreportdetection ofseveralmodesofdegradation experienced intheEdFunits.Thereis-noevidenceofpost-chemical cleaninginspections indicating any.significant materialloss,noristhereevidenceofwrapperhavingdropped.WhileTSPligamentcrackinghasoccurredinunitswithcarbonsteelsupport,plateswithdrilled'ound holesand.flow'oles,thereisnoevidenceindicating TSPligamentcrackingorthinningthatisprogressive andcontinuing.
Thefollowingtablesummarizes theapplicable WOGconclusions concerning thesusceptibility ofSGslikeouiunit1series51SGstosecondary sideinternals degradation.
TABLE1DEGRADATION TYPEErosionCorrosion:
MoistureSeparator TSPFlowHole/Ligaments FeedRing/8-Tubes Cracking:
TSPLigaments NearWedges**TSPLigaments NearPatchPlatesCarbonSteelTSPLigaments (randomareas)LEVELOFSUSCEPTIBILITY NNX*"Other:WrapperNearSupports**NWrapperDrop**NX~oservexnsomeSGsN=notsusceptible toEdFcasualfactorsL~lowsusceptibility toEdFcasualfactors*~variousindication ofdegradation maybeartifacts ofmanufacturing relatedtopatchplateplugweldsand/ordrillingalignment
**variousWestinghouse designfeatures'rebeneficial relativetosomeoftheSGdesignfeaturesofforeignmanufacturers Site-SecificFindinsTheunit1SGswerelastinspected inthespringof1997.In~additiontothestandardeddycurrenttubeinspection, additional measureswereperformed toassuretheintegrity oftheSGinternals.
Theseinspections, coupledwithrelatedfindingsfrompreviousinspections, demonstrate thatthe'reasnotedintable1havebeenperiodically examinedwithnoabnormalconditions
.noted.
et~~Attachment toAEP:NRC:1166AM Page4Thefollowing discussion presentstheinternals inspection scopeandfindingsfortheunit11997refueling outage(U1R97).A100%computerdatascreening (CDS)sortwasperformed onthelowfrequency bobbincoildatafromeachSGtoaddressthepotential forTSPdamageorligamentcracking.
Indications ofpossibleligamentdamagewereexaminedusingamotorized rotatingpancakecoil(MRPC)probe.Theindications weresubsequently dispositioned ashavingnodegradation found(NDF)ordetermined tobealignedwiththepatchplate,thusyieldinga"false"indication.
Onetube,R39/C22inSG11wasnotedtohavea0.78'oltMRPCindication attheseventhhotlegsupportplate,nearthewedgelocation.
Researchofthepreviousoutagedataconfirmed thiscondition hasbeenpresentforatleastthreeyears.Thisindication willcontinuetobemonitored duringfutureeddycurrentinspections.
Regarding theperformance ofsecondary sidevisualinspections, thefollowing activities wereperformed ineachSG(unlessotherwise noted)duringtheU1R97foreignobjectsearchandretrieval operations:
~Pre-Sludge LanceInspection
-Avisualinspection wasperformed toidentifythetubing/sludge conditions atthetubesheet prior,tolancing.Thisinspection includedtheannulusanddividerlane.~Post-Lance Inspection
-Avisualinspection wasperformed toverifytheeffectiveness ofthesludgeremovalprocessandgeneraltubesheet/tubing conditions atthetopofthetubesheet.
Theinspection consisted oftheannulus,dividerlaneandaninnerbundlepassinboththehotandcoldlegsides..WrapperBarrelInspection
-Thisvisualinspection wasperformed to.verifytheintegrity ofthewrapperbarrelsupportstructure.
FirstTubeSupportLigament(2,SGs)-Thisinspection involvedavisualreviewofthefirstTSPbetweenthewrapperbarrelandthetubebundledirectlyabovethehandhold:
Thepre/post-lance inspections confirmed" theeffectiveness ofthesludgeremovaloperations andthegeneralcondition ofthetubingatthetubesheet.
Noanomalies orloosepartswerenotedbytheinspection.
Thewrapperbarrelinspection producednoevidenceofslippageormovement.
Additional verification oftheintegrity ofthesupportstructure wasprovidedbythesuccessful installation ofthesludgelanceequipment.
Thelackofanyinterferences'uring thisinstallation providedassurance thatnodeformation had~occurred.
Inspections ofthefirstsupportplateidentified nosignsofanomalies ineitherofthetwoSGsinspected.
Whilenoinspections wereperformed duringU1R97ontheupperinternals, previousinspections haveidentified onlyminimalwear.'uring the1995inspection, fifteenJ-nozzles andthefeedringteesectionofoneSG.wereinspected.
TheJ-nozzles weretermedtobeinverygoodcondition, withnothinningobservedonthethermallinerandtee.Priortothe1995inspection, extensive inspections wereconducted in1989inwhichvisualinspections wereconducted
.ontheJ-nozzles ofthreeSGs.Thevisualexamination ofoneof l~
Attachment toAEP:NRC:1166AM Page5theseSGswassupplemented byanaddedultrasonic test(UT)examination.
NeitherthevisualorUTexaminations notedanyapparentdegradation.
Theseinspections haveindicated thatdegradation intheupperinternals isaslowprogressing phenomena.
Basedonminimaldegradation todateandthenearendoflifefortheseSGs,noexaminations wereperformed duringU1R97.SafetAssessment Thefollowing safetyconcernshavebeenpostulated byWOGrelativetotheFrenchSGinternals degradation experience.
~Lossofsupportinthetube.bundleleadingtowear,andpossibleprimary-to-secondary leakageorinadequate burstmargins.Increased TSPdeformation duringapostulated loss-of-coolant accident(LOCA)plussafeshutdownearthquake (SSE)'event,resulting inunacceptable SGtubecollapseorsecondary-to-primaryinleakage.
i~Generation ofalooseobjectinthesecondary sideofaSGthatmayresultintubewearorimpacting, andpossiblyprimary-to-secondary leakage.Asdiscussed below,industryexperience andvariousstandardpractices aretypically employedtoprovideassurance ofSGintegrity andnegatethepotential forthese'oncerns.
Asevidenced fromthepreviously discussed U1R97inspection results,ourunit1experiences andpractices mirrorthatoftheindustry.
Basedon'reviewofthetable1information, theonlydegradation typesthatmayoccurdomestically thatcouldresult,inthelossofTSPintegrity areTSPflowhole/ligament erosion-corrosion, TSPligamentcrackingnearthepatchplates,andTSPligamentcrackinginrandomareas.Thereisnoindustryevidenceofpost-chemical cleaninginspections indicating.
significant materialloss,noris'thereevidenceofanywrapperhavingdropped.WhileTSP'ligament crackinghasoccurredinunitswithcarbonsteel.supportplateswithdrilledroundholesandflowholes,thereisnoevidenceindicating TSPligamentcrackingorthinningthatisprogressive andcontinuing.
Utilities withseries51SGswithcarbon'steelsupportplatesinspectasignificant percentage ofSGtubeseveryoutagewithabobbincoilprobe(unit1inspects100%).Ifsectionsofthetubesupportweremissing,itwouldbereadilydetectable becauseofalackofeddycurrent.responseattheTSPelevation.
Thereisnoincreased susceptibility toligamentcrackingnearthewedgesupportsintheseries51SGdesign.Eithertherearenoflowholesextending totheperiphery
'atthewedgelocations, or=.thewedgesarenotweldedtotheTSPs,asisthecasewiththeEdF51MSG.Existingcalculations evaluating theeffectsofLOCAplusSSEloadingsonthetubebundlecontinuetoapplyindetermining whethercertaintubesshouldbeexcludedfromapplication ofthevoltagebasedpluggingcriteria, orwhethercertaintubesshouldberemovedfromserviceinplantsthatdonotcurrently havethecriteria, butmayhaveSGtubesexperiencing
~crackingatTSPintersections.
Attachment toAEP:NRC:1166AM Page6Anotheroccurrence resulting fromSGinternaldegradation thatmay.affectaSGinperforming itsintendedsafetyfunctionisthepotential fortubewearandprimary-to secondary leakageduetothegeneration ofalooseobjectonthesecondary sideoftheSG.Thismayoccurduetoerosion-corrosion ofthemoistureseparators, feedring/J-nozzle, orTSPflowholes,ortheoccurrence ofTSPligamentcracking.
Ifprimary-to-secondary leakageshouldoccurbecauseoftubewearfromalooseobject,theexpectedconsequences wouldbeboundedbyasingletuberuptureeventand,therefore, wouldremainwithinthecurrentlicensing basisoftheplant.Itisourpositionthatlooseobjectsshouldberemovedwheneverpossible.
Tubesobservedtohavevisibledamageareeddycurrentinspected andpluggedasnecessary.
ElementsoftheSGprogram,includi'ng eddycurrentinspection, foreignobjectsearchandretrieval duringeachrefueling outage,andloosepartsmonitoring areinplacetohelpensurethemaintenance oftubeintegrity duringplantoperation.
Becausenointernals degradation ofconsequence hasbe'enobservedontheunit1SGs,itisexpectedthat,neartermdegradation wouldbelimitedinextent,suchthat'thetubeswillremaincapableofsustaining theconditions ofnormaloperations, including operational transient, designbasisaccidents, externalevents,andnaturalphenomena, permitting theaffectedSGtoperformitssafetyfunction.
Inservice InsectionPlanBecauseof.thependingSGreplacement, itisprojected thattheunit1SGswillundergoonlyonemoreinspection priortothereplacement outage.Basedonthepreviousdiscussions, theupcominginspection planwillcloselymirroractivities performed in1997.Theplannedworkscope issummarized asfollows.A100%CDSscanwillbeperformed onthebobbincoildatafor.evidenceofsupportplate/ligament damage.Indication disposition willbebyMRPCprobe.Notethatthebobbincoilexamination willbeperformed on100%ofthein-service tubing.Foreignobjectsearchandretrieval operations willbeperformed ineachSGtoaccessthetubingandsupportstructure conditions aswellasverifythesludgeconditions withintheSGs.Accessible tubesheet surfacesandtubesatthetopofthetubesheet willbetargetedduringtheinspection.
Duringsludgelanceoperations tobeperformed ineachSG,itwillbeverifiedthatthelancingequipment canbeinsertedwithoutinterference.
Successful installation willprovideverification ofwrapperintegri.ty.
Ifinterference isdetected, thelowerwrappersupportblockswillbevisuallyinspected.
Thewrapperblock'inspection willalsobeconducted ifanyevidenceoftubedamageintheperiphery ofthefirstTSPisdetected.
Inspections willbeperformed onthefirstanduppermost TSPofoneSGtoassessfoulingconditions andidentifyanyevidenceofcorrosion ordamage.  
~~Attachment toAEP:NRC:1166AM Page7Basedonsiteinspection experience, noupper-bundleinspections areplannedduringtheupcominginspection.
Shouldtheunit.1SGsbereplacedduringthenextoutage,ourinspection planwillberevisedappropriately.
-UNIT2SGPROGRAMINTERNALS INSPECTION SGDescritionIn1989,thefouroriginalunit2Westinghouse series53.SGswerereplacedwithWestinghouse series54FSGs.Keydesignfeaturesofthereplacement SGs.includethermally treatedalloy690tubing,afulldepthhydraulic expansion atthetube-to-tubesheet
'joint,quatrefoil stainless steelsupportplates,.increased row1U-bendradius,andheattreatedlowrowU-bends.ThenominaltubeODis0.875inches,withanominalwallthickness of0.050inches.RelatedIndustrFindinsAsdiscussed inWCAP-15002, revision1,twelveplantswithseriesD,E,44F,andFSGssuppliedinformation totheWOGconcerning resultsofSGsecondary sideinspections andrelevanttubeinspections forTSPconditions.
Forthemost,part,thefindingsdidnotreportdetection ofseveralmodesofdegradation experienced intheEdFunits.Thereisnoevidenceofpost-chemicalcleaninginspections indicating significant materialloss,.noristhereevidenceofanywrapper,havingdropped.WhileTSPligamentcrackinghasoccurredinunitswithcarbonsteelsupportplateswithdrilledroundholesandflowholes,thereisnoevidenceindicating TSPligamentcrackingorthinningthatisprogressive andcontinuing.
Thefollowingtablesummarizes theapplicable WOGconclusions concerning thesusceptibility ofSGsliketheunit2series54FSGs.tosecondary sideinternals degradation.
TABLE2DEGRADATION TYPELEVELOFSUSCEPTIBILITY ErosionCorrosion:
MoistureSeparator TSPFlowHole/Ligaments FeedRing/8-Nozzles Cracking:
TSPLigaments
***WrapperNearSupports*+Other:NAWrapperDrop**
Attachment toAEP:NRC:1166AM Page8XLNA~*aobservedinsomeSGslowsusceptibility notapplicable variousindication ofdegradation maybeartifacts ofmanufacturing relatedtopatchplateplugweldsand/ordrillingalignment variousWestinghouse
.designfeatures'arebeneficial relativetosomeoftheSGdesignfeaturesofforeignmanufacturers Site-SecificFindinsTheunit2SGswerelastinspected inthefallof1997.Inadditiontothestandardeddy"currenttubei.nspection, othermeasureswereperformed toassuretheintegrity oftheSGinternals.
Theseinspections, coupledwithrelatedfindingsfrom'revious inspections anddesignattributes oftheunit2series54FSGs,demonstrate
.,thattheareasofinterestas,noted"intable2havebeenaddressed withnoabnormalconditions noted.Thefollowing discussion presentstheinternals inspection scopeandfindingsfortheunit21997refueling outage(U2R97).Thefollowing activities wereperformed ineachSG(unlessotherwise noted)duringtheU2R97foreignobjectsearchandretrieval operations.
~Pre-sludge LanceInspection
-Avisualinspection wasperformed toidentifythetubing/sludge, conditions atthetubesheet priortolancing.Thisinspection includedtheannulusanddividerlane.Post-Lance Inspection
-Avisualinspection wasperformed toverifytheeffectiveness ofthesludgeremovalprocessandthegeneraltubesheet/tubing conditions onthetopofthetubesheet.
Areasreviewedconsisted oftheannulus,dividerlaneandaninnerbundlepass.onboththehot.andcoldlegsides.~Sixthand'Seventh TSP.(OneSG)-Avisualinspection reviewedthesixthandseventhTSPstoaccesssludgeconditions andfoulingconditions intheupperregionoftheoneSG.Thepre/post-lance inspection confirmed theeffectiveness ofthesludgeremovaloperations andthegeneralcondition ofthetubingat'hetubesheet.
No,,degradation orsignsofabnormalities werenotedduringtheinspection.
Theuppersupportplateinspection notednosignsofdamagedcomponents ordegradation.
Regarding TSPdamage.orligamentcracking, eddycurrentassessments werenotperformed becausethequatrefoil broachedholesupportplatedesignmakesthistechnique notapplicable fordetecting damage.Noabnormalities weredetectedinthisareaduringtheforeignobjectsearchandretrieval operations thatwouldsuggestdamageofthisnature.Ingeneral,erosion-corrosion induceddegradation isviewedasalowsusceptibility eventbecausetheplatesareconstructed ofstainless steel.Specificinspection ofthewrapperbarrelareawasnotperformed.
However,wrapperconditions didnotaffecttheinstallation ofthe Attachment toAEP:NRC:1166AM Page9sludgelancingequipment thatwasperformed ineachSG.Therefore, itwasconcluded thatthewrapperhadnotslippedormoved.Whilenoinspections wereperformed duiingU2R97,on, theupperinternals, previousinspections havebeenperformed.
Duringthe1994inspection, tenJ-nozzles andthefeedringteesectionofoneSGwereinspected.
Noerosionwasnotedduringtheinspection.
Theoriginal, feedrings/J-nozzles werereplacedwhentheunit2SGswerereplacedin1989.Thereplacement feedrings areconstructed ofextrastrongcarbonsteelandtheJ-nozzles aremade.from,alloy600,whichislesssusceptible toerosiondamagethan.thetypicalcarbonsteelJ-nozzles.
Theseinspections indicatethatdegradation intheupperinternals isaslowprogressing phenomena.,
Basedonminimaldegradation to-date,noexaminations werescheduled'for U2R97.SafetAssessment Asnotedintheunit1safetyassessment, thefollowing safetyconcernshavebeenpostulated bytheWOGrelativetotheFrenchSGinternals degradation experience.
~>>Lossofsupportleadingtowearandpossibleprimary-to-secondary leakageorinadequate burstmargins..Moresignificant TSPdeformation duringapostulated LOCAplusSSEevent,resulting inunacceptable SGtubecollapseorsecondary-to-primary inleakage.
Generation ofalooseobjectinthesecondary sideofaSGwhichmayresultintubewearorimpacting andpossiblyprimary-to-secondary leakage.Asdiscussed below,design.features, industryexperience, andvariousstandardpractices aretypically employedto-provideassurance ofSGintegrity andnegatethepotential fortheseconcerns.
Previously discussed U2R97inspection resultsindicateourunit2experiences andpractices aresimilartothatoftheindustry.
Basedonareviewofthetable2information, theonlydegradation typesthatmayoccurdomestically thatwouldlikelyresultinthelossofTSPintegrity areTSPflowhole/ligament erosion-corrosion, TSPligamentcrackingnearthepatchplates,andTSPligamentcrackinginrandomareas.Thereisnoindustryevidenceofpost-chemicalcleaninginspections resulting inthediscovery ofanysignificant materialloss,noristhere.evidence ofanywrapperhavingdropped.NoTSPligamentindications havebeenfoundinsteamgenerators withstainless steelTSPs.Thispopulation includestheunit2SGs.Noincreased susceptibility toligamentcrackingnearthewedgesupportshasbeenidentified intheseriesD,E,44F,andF(unit.2)SGsdesigns.Existingcalculations evaluating theeffectsofLOCAplusSSEloadingsonthetubebundlecontinuetoapplyindetermining whethercertaintubesshouldbeexcludedfromapplication ofthevoltagebasedpluggingcriteria, orwhethercertain.tubesshouldberemovedfromserviceinplantsthatdonotcurrently haveacriteriabutmayhaveSGtubesexperiencing crackingatTSPintersections.  


AttachmenttoAEP:NRC:1166AMPage10AnotheroccurrenceresultingfromSGinternaldegradationthatmayaffectaSGinperformingitsintendedsafetyfunctionisthe"potentialfortubewearandprimary-to-secondaryleakageduetothegenerationofalooseobjectonthesecondarysideoftheSG.Thismayoccurbecauseoferosion-corrosionofthemoistureseparatorsortheoccurrenceofTSPligamentcracking.Ifprimary-to-secondaryleakageshouldoccurduetotubewearfromalooseobject,theexpectedconsequenceswouldbeboundedbyasingletuberuptureeventandwouldremainwithinthecurrentlicensingbasisoftheplant.Itisourpositionthatlooseobjectsshouldberemovedwheneverpossible.,Tubesobservedtohavevisibledamageareeddycurrentinspectedandpluggedasnecessary.ElementsoftheSGprogram,includingeddycurrentinspection,foreignobjectsearchandretrievalduringeachrefuelingoutage,andloosepartsmonitoringareinplacetohelpensurethemaintenanceoftubeintegrityduringplantoperation.Becausenointernalsdegradationofconsequencehasbeenobservedontheunit2SGs,itisexpectedthatfuturedegradationwouldbelimitedinextentsuchthatthetubeswillremaincapableofsustainingtheconditionsofnormaloperations,includingoperationaltransient,designbasisaccidents,externalevents,andnaturalphenomena,permittingtheaffectedSGtoperformitssafetyfunction.Basedontheabove,implementationofthefollowinginspectionplanisplannedontheunit2SGstoaddressthevarioustypesofSGsecondarysideinternalsdegradationthatmayoccurinWestinghouse-designedSGs.Thisplanmaybeamended,pendingtheresultsofadetailedindustryevaluationthatisexpectedtobecompletedbymid-1998.InserviceInsectionPlanGiventheprimarysideeddycurrent,inspectionresultinginaC-1classificationandtheabsenceofsecondarysidefindingsduringthelastinspection,noinspectionactivitiesareplannedattheendofthecurrentcycle(cycle12).Inspectionscopeforthesubsequentoutagehasnotbeenfinalized.However,ataminimum,plannedsecondarysideinspectionswillbesimilartothoseperformedin1997.Theplannedworkscopeissummarizedasfollows.ForeignobjectsearchandretrievaloperationswillbeperformedineachSGtoaccessthetubingandsupportstructureconditionsaswellasverifythesludgeconditionswithintheSGs.Accessibletubesheetsurfacesandtubesatthetopofthetubesheetwillbetargetedduringtheinspection.DuringsludgelanceoperationstobeperformedineachSG,itwillbeverifiedthatthelancingequipmentcanbeinsertedwithoutinterference.Successfulinstallationwillprovideverificationofwrapperintegrity.Ifinterferenceisdetected,thelowerwrappersupportblockswillbevisuallyinspected.ThewrapperblockinspectionwillalsobeconductedifevidenceoftubedamageintheperipheryofthefirstTSPisdetected.InspectionswillbeperformedonthefirstanduppermostTSPofoneSGtoassessfoulingconditionsandidentifyevidenceofcorrosionordamage.
Attachment toAEP:NRC:1166AM Page10Anotheroccurrence resulting fromSGinternaldegradation thatmayaffectaSGinperforming itsintendedsafetyfunctionisthe"potential fortubewearandprimary-to-secondary leakageduetothegeneration ofalooseobjectonthesecondary sideoftheSG.Thismayoccurbecauseoferosion-corrosion ofthemoistureseparators ortheoccurrence ofTSPligamentcracking.
I11a Attachmentto.AEP:NRC:1166AMPage11Toverifyconditionsintheupperbundlearearemainconsistentwithpastinspections,an.inspectionwillbeperformedonthemoistureseparatorunitsandapopulationofJ-nozzlesandthefeedringteeareaofoneSG.CONCLUSIONSTheaforementionedinspectionprogramsare,basedonindustryexperienceandoursite-specificinspectionfindings.WebelievetheseprogramsareofanaturetoadequatelyaddressconcernsofinternalsdegradationasnotedinGL97-06.}}
Ifprimary-to-secondary leakageshouldoccurduetotubewearfromalooseobject,theexpectedconsequences wouldbeboundedbyasingletuberuptureeventandwouldremainwithinthecurrentlicensing basisoftheplant.Itisourpositionthatlooseobjectsshouldberemovedwheneverpossible.,
Tubesobservedtohavevisibledamageareeddycurrentinspected andpluggedasnecessary.
ElementsoftheSGprogram,including eddycurrentinspection, foreignobjectsearchandretrieval duringeachrefueling outage,andloosepartsmonitoring areinplacetohelpensurethemaintenance oftubeintegrity duringplantoperation.
Becausenointernals degradation ofconsequence hasbeenobservedontheunit2SGs,itisexpectedthatfuturedegradation wouldbelimitedinextentsuchthatthetubeswillremaincapableofsustaining theconditions ofnormaloperations, including operational transient, designbasisaccidents, externalevents,andnaturalphenomena, permitting theaffectedSGtoperformitssafetyfunction.
Basedontheabove,implementation ofthefollowing inspection planisplannedontheunit2SGstoaddressthevarioustypesofSGsecondary sideinternals degradation thatmayoccurinWestinghouse-designed SGs.Thisplanmaybeamended,pendingtheresultsofadetailedindustryevaluation thatisexpectedtobecompleted bymid-1998.
Inservice InsectionPlanGiventheprimarysideeddycurrent,inspection resulting inaC-1classification andtheabsenceofsecondary sidefindingsduringthelastinspection, noinspection activities areplannedattheendofthecurrentcycle(cycle12).Inspection scopeforthesubsequent outagehasnotbeenfinalized.
However,ataminimum,plannedsecondary sideinspections willbesimilartothoseperformed in1997.Theplannedworkscope issummarized asfollows.Foreignobjectsearchandretrieval operations willbeperformed ineachSGtoaccessthetubingandsupportstructure conditions aswellasverifythesludgeconditions withintheSGs.Accessible tubesheet surfacesandtubesatthetopofthetubesheet willbetargetedduringtheinspection.
Duringsludgelanceoperations tobeperformed ineachSG,itwillbeverifiedthatthelancingequipment canbeinsertedwithoutinterference.
Successful installation willprovideverification ofwrapperintegrity.
Ifinterference isdetected, thelowerwrappersupportblockswillbevisuallyinspected.
Thewrapperblockinspection willalsobeconducted ifevidenceoftubedamageintheperiphery ofthefirstTSPisdetected.
Inspections willbeperformed onthefirstanduppermost TSPofoneSGtoassessfoulingconditions andidentifyevidenceofcorrosion ordamage.
I11a Attachment to.AEP:NRC:1166AM Page11Toverifyconditions intheupperbundlearearemainconsistent withpastinspections, an.inspection willbeperformed onthemoistureseparator unitsandapopulation ofJ-nozzles andthefeedringteeareaofoneSG.CONCLUSIONS Theaforementioned inspection programsare,basedonindustryexperience andoursite-specific inspection findings.
Webelievetheseprogramsareofanaturetoadequately addressconcernsofinternals degradation asnotedinGL97-06.}}

Revision as of 07:14, 29 June 2018

Forwards Response to GL 97-06, Degradation of SG Internals. GL Was Issued to Alert Addressees to Foreign & Domestic Findings of Damage to SG Internals,Emphasize Importance of Performing Comprehensive Exams of Internals
ML17334B729
Person / Time
Site: Cook  American Electric Power icon.png
Issue date: 04/14/1998
From: FITZPATRICK E
INDIANA MICHIGAN POWER CO.
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
AEP:NRC:1166AM, GL-97-06, GL-97-6, NUDOCS 9804200484
Download: ML17334B729 (17)


Text

CATEGORYREGULATORY INFORMATION DISTRIBUTION SYSTEM"(RIDS)"

4ACCESSION NBR:9804200484 DOC.DATE:

98/04/14NOTARIZED:

YESFACIL:50-315 DonaldC.CookNuclearPowerPlant,Unit1,IndianaM50-316Donald.C.CookNuclearPowerPlant,Unit2,IndianaMAUTH;NAME AUTHORAFFILIATION FITZPATRICK,E.

IndianaMichiganPowerCo.RECIP.NAME RECIPIENT AFFILIATION DocumentControlBranch(Document ControlDesk)DOCKET¹0500031505000316

SUBJECT:

ForwardsresponsetoGL97-06,"Degradation ofSGIntervals.

DISTRIBUTION CODE:ZOOIDCOPIESRECEIVED:,LTR iENCLiSIZE:TITLE:ORSubmittal:

GeneralDistribution NOTES:RECIPIENT IDCODE/NAME PD3-3LASTANG,JCOPIESLTTRENCL,1111RECIPIENT IDCODE/NAME PD3-3PDCOPIESLTTRENCL11EINTERNAL.-ENT---1NRR/DE/EMCB NRR/DSSA/SPLB NUDOCS-ABSTRACT EXTERNAL:

NOAC11111111NRR/DE/ECGB/A NRR/DRCH/HICB NRR/DSSA/SRXB OGC/HDS2NRCPDR1111111011DNOTETOALL"RIDS"RECIPIENTS:

PLEASEHELPUSTOREDUCEWASTE.TOHAVEYOURNAMEORORGANIZATION REMOVEDFROMDISTRIBUTION LISTSORREDUCETHENUMBEROFCOPIESRECEIVEDBYYOUORYOURORGANIZATION, CONTACTTHEDOCUMENTCONTROLDESK(DCD)ONEXTENSION 415-2083TOTALNUMBEROFCOPIESREQUIRED:

LTTR13ENCL12 IndianaMichigan~PowerCompany500CircleDriveBuchanan, Ml491071395 IlfNENANAMICHIGANPQWMApril14,1998AEP:NRC:1166AM DocketNos.:50-31550-316U.S.NuclearRegulatory Commission ATTN:DocumentControlDeskMailStop0-Pl-17Washington, D.C.20555-0001 Gentlemen:

DonaldC.CookNuclearPlantUnits1and2RESPONSETONRCGENERICLETTER(GL)97-06DEGRADATION OFSTEAMGENERATOR INTERNALS Thisletteranditsattachment provideinformation requested inGL97-06,concerning steamgenerator internals degradation.

Sincerely, pugE.E.Fitzpatrick VicePresident J'SWORNTOANDSUBSCRIBED BEFOREMEgATHIS~DAYOF~/Z.,1998NotaryPublic/.Sd//vlbAttachment Z.A.AbramsonA.B.BeachMDEQ-DW&RPDNRCResidentInspector 8.R.SampsonUNDALBOEI.CKENotaryPublic,BerrienCounty,MlMCommission ExpiresJanuary21,200I2001yQoI9804200484 9804l4PDRADOCK050003iSpPDR ATTACHMENT TOAEP:NRC:1166AMRESPONSETONRCGENERICLETTER97-06DEGRADATION OFSTEAMGENERATOR INTERNALS 5.~'Attachment toAEP:NRC:1166AM Page1INTRODUCTION Genericletter(GL)97-06wasissuedto'alertaddressees toforeignanddomesticfindingsofdamagetosteamgenerator (SG)internals, emphasize theimportance ofperforming comprehensive examinations ofSGinternals, andrequestinformation thatwillenabletheNRCstafftoverifytheinternals ofCookNuclearPlant'sSGsconform-tothecurrentlicensing basis.BACKGROUND ANDDESCRIPTION OFCIRCUMSTANCES Frenchauthorities havereportedvariousSGtubesupportplate(TSP)damagemechanisms.

Damagehas.-includedwastageintheuppermost TSPduetomisapplication of.achemicalcleaningprocess,brokenTSPligaments resulting frominadequate clearance for,differential thermalexpansion, andTSPwastageatvariouselevations apparently involving acorrosion orerosion-corrosion mechanism ofundetermined origin.Otherins'tances ofinternals degradation includewrapperdrop/cracking ataforeignutilitythatissuspected tohavebeencausedbyseverecoolingtransients, andinstances oferosion-corrosion ofeggcratesupportsinuntubedareasinitiated "byunknowncausesthatoccurredatadomesticfacility.

Theseinstances.

highlight thepotential fordegradation mechanisms thatmayleadtoTSPandtubewrapperdamage..Asaresultofthisconcern,GL97-06requests:

1.Discussion ofanyprogramsinplacetodetectdegradation ofSGinternals andadescription ofinspection plans(scope,frequency, methods,andequipment)

.Thisdiscussion should.address.thefollowing information foreachfacility.

a~b.C.Whetherinspection recordshavebeenreviewedforindications ofTSPsignalanomalies fromeddycurrenttestingofSGtubes'hat maybeindicative ofsupportplateorligamentdamage.Whethervisualorvideocamerainspections havebeenperformed onthesecondary sidetogaininformation onthecondition ofSGinternals (e.g.,supportplates,tubebundlewrappers, etc.).Whetherdegradation, ofSGinternals hasbeendetected, andhowitwasassessedanddispositioned.

2.Intheeventnoprogramisinplacetodetectinternals degradation, provideadiscussion orjustification fordevelopment ofaprogramorwhysuchaprogramisnot:needed..

PriortoissuanceofthisGL,Westinghouse OwnersGroup(WOG),ElectricPowerResearchInstitute (EPRI),andNuclearEnergyInstitute (NEI)developed anactionplantoassessthesusceptibility ofSGsecondary "sidedegradation.

Weintendtofollowtheindustryactionplanasmodifiedbyoursite-specific experience.

Includedintheactionplanisarequirement tounderstand thecausalfactorsinvolvedinthedegradation experienced intheFrenchunits.Thisinformation iscapturedinEPRIreportGC-109558, "SteamGenerator Internals Degradation:

Attachment toAEP:NRC:1166AM Page2ModesofDegradation DetectedinEdFUnits".Thisreportwassubmitted'o theNRCviaanNEZletter,datedDecember19,1997.-WOGhasreviewedEPRZGC-109558 relativetothe,designofseries51SGsanddetermined limitedpotential susceptibility.

Forplantswithseries51SGs,thisconclusion isdocumented inWCAP-15002, revision1,."Evaluation ofEdFSteamGenerator Internals Degradation

-ImpactofCausalFactorsonWestinghouse

.51SeriesSteamGenerators",

December1997.Theseries51SGsarethemostsimilarmodelSGtothatoftheElectricith deFrance(EdF).unitsandareinstalled inunit1.WCAP-.15002, revision1,documents visualinspections performed attheseries51SGplants.Ztwasconcluded

.thatthenumber.ofplantsthathavebeeninspected andtheinspection resultsdemonstrate thatthecausalfactorsidentified byEdFdonotjeopardize thecontinued operability ofWestinghouse series51SGs.Thisconclusion issupported bythe-capability ofeddycurrentinspections to,detect.

detrimental effectsontubingduetowearcausedbyTSPligamentdegradation, loose'parts, andsecondary side'lowdistribution changes.Foreignobjectsearchandretrieval

~effortsaretypically conducted asstandardpracticetodiscoveror~retrievelooseparts,thuslimitingthepotential fordamage.AresponsetoGL97-06hasbeencompleted forunit1addressing thesusceptibility oftheunit1SGstointernals degradation, specificunit1inspection practices andrecentinspection results,along,withadiscussion ofsubsequent plantoperation withpotential SGinternals degradation ofthetypeexperienced;in theFrenchunits(andothertypesofdegradation experienced domestically)

~Thisdiscussion beginsinthe"UNIT1SGPROGRAM(INTERNALS 1NSPECTION)

"sectionofthisattachment.

BecauseadetailedWestinghouse evaluation hasnotbeenperformed

,forourunit2SGs,inspection recommendations have.beenidentified onaninterimbasis.Industryrepresentatives haveindicated that'valuations shouldbecompleted byMay1998,andtheresultswillbefactoredintotheunit2SGprogram.Assuch.theresponseto'tem1forunit,2,whichisdetailedinthe"UNIT2SGPROGRAM(INTERNALS INSPECTION)"

sectionofthisattachment, maybemodifiedinthefutureasdictatedbytheresultsofthependingevaluation.

UNIT1SGPROGRAMINTERNALS INSPECTION SGDescritionUnit1containsfourWestinghouse series51SGsthatwereplacedinservicein1975.Keydesignfeaturesincludealloy600millannealedtubing,apartialdepthhardrollexpansion atthetube-to-tubesheet joint,anddrilledcarbonsteelsupportplates.Thenominaltubeoutsidediameter(OD)is0.875incheswithanominalwallthickness of0.050inches.Thefourunit1SGsarepresently scheduled forreplacement intheyear2000.

Attachment to=AEP:NRC:1166AMPage3RelatedIndustFindinsAsdiscussed inWCAP-15002, revision1,eighteenplantswithseries51SGssuppliedinformation totheWOGconcerning resultsofSGsecondary sideinspections andrelevanttubeinspections forTSPconditions.

Theseresultsdidnotreportdetection ofseveralmodesofdegradation experienced intheEdFunits.Thereis-noevidenceofpost-chemical cleaninginspections indicating any.significant materialloss,noristhereevidenceofwrapperhavingdropped.WhileTSPligamentcrackinghasoccurredinunitswithcarbonsteelsupport,plateswithdrilled'ound holesand.flow'oles,thereisnoevidenceindicating TSPligamentcrackingorthinningthatisprogressive andcontinuing.

Thefollowingtablesummarizes theapplicable WOGconclusions concerning thesusceptibility ofSGslikeouiunit1series51SGstosecondary sideinternals degradation.

TABLE1DEGRADATION TYPEErosionCorrosion:

MoistureSeparator TSPFlowHole/Ligaments FeedRing/8-Tubes Cracking:

TSPLigaments NearWedges**TSPLigaments NearPatchPlatesCarbonSteelTSPLigaments (randomareas)LEVELOFSUSCEPTIBILITY NNX*"Other:WrapperNearSupports**NWrapperDrop**NX~oservexnsomeSGsN=notsusceptible toEdFcasualfactorsL~lowsusceptibility toEdFcasualfactors*~variousindication ofdegradation maybeartifacts ofmanufacturing relatedtopatchplateplugweldsand/ordrillingalignment

    • variousWestinghouse designfeatures'rebeneficial relativetosomeoftheSGdesignfeaturesofforeignmanufacturers Site-SecificFindinsTheunit1SGswerelastinspected inthespringof1997.In~additiontothestandardeddycurrenttubeinspection, additional measureswereperformed toassuretheintegrity oftheSGinternals.

Theseinspections, coupledwithrelatedfindingsfrompreviousinspections, demonstrate thatthe'reasnotedintable1havebeenperiodically examinedwithnoabnormalconditions

.noted.

et~~Attachment toAEP:NRC:1166AM Page4Thefollowing discussion presentstheinternals inspection scopeandfindingsfortheunit11997refueling outage(U1R97).A100%computerdatascreening (CDS)sortwasperformed onthelowfrequency bobbincoildatafromeachSGtoaddressthepotential forTSPdamageorligamentcracking.

Indications ofpossibleligamentdamagewereexaminedusingamotorized rotatingpancakecoil(MRPC)probe.Theindications weresubsequently dispositioned ashavingnodegradation found(NDF)ordetermined tobealignedwiththepatchplate,thusyieldinga"false"indication.

Onetube,R39/C22inSG11wasnotedtohavea0.78'oltMRPCindication attheseventhhotlegsupportplate,nearthewedgelocation.

Researchofthepreviousoutagedataconfirmed thiscondition hasbeenpresentforatleastthreeyears.Thisindication willcontinuetobemonitored duringfutureeddycurrentinspections.

Regarding theperformance ofsecondary sidevisualinspections, thefollowing activities wereperformed ineachSG(unlessotherwise noted)duringtheU1R97foreignobjectsearchandretrieval operations:

~Pre-Sludge LanceInspection

-Avisualinspection wasperformed toidentifythetubing/sludge conditions atthetubesheet prior,tolancing.Thisinspection includedtheannulusanddividerlane.~Post-Lance Inspection

-Avisualinspection wasperformed toverifytheeffectiveness ofthesludgeremovalprocessandgeneraltubesheet/tubing conditions atthetopofthetubesheet.

Theinspection consisted oftheannulus,dividerlaneandaninnerbundlepassinboththehotandcoldlegsides..WrapperBarrelInspection

-Thisvisualinspection wasperformed to.verifytheintegrity ofthewrapperbarrelsupportstructure.

FirstTubeSupportLigament(2,SGs)-Thisinspection involvedavisualreviewofthefirstTSPbetweenthewrapperbarrelandthetubebundledirectlyabovethehandhold:

Thepre/post-lance inspections confirmed" theeffectiveness ofthesludgeremovaloperations andthegeneralcondition ofthetubingatthetubesheet.

Noanomalies orloosepartswerenotedbytheinspection.

Thewrapperbarrelinspection producednoevidenceofslippageormovement.

Additional verification oftheintegrity ofthesupportstructure wasprovidedbythesuccessful installation ofthesludgelanceequipment.

Thelackofanyinterferences'uring thisinstallation providedassurance thatnodeformation had~occurred.

Inspections ofthefirstsupportplateidentified nosignsofanomalies ineitherofthetwoSGsinspected.

Whilenoinspections wereperformed duringU1R97ontheupperinternals, previousinspections haveidentified onlyminimalwear.'uring the1995inspection, fifteenJ-nozzles andthefeedringteesectionofoneSG.wereinspected.

TheJ-nozzles weretermedtobeinverygoodcondition, withnothinningobservedonthethermallinerandtee.Priortothe1995inspection, extensive inspections wereconducted in1989inwhichvisualinspections wereconducted

.ontheJ-nozzles ofthreeSGs.Thevisualexamination ofoneof l~

Attachment toAEP:NRC:1166AM Page5theseSGswassupplemented byanaddedultrasonic test(UT)examination.

NeitherthevisualorUTexaminations notedanyapparentdegradation.

Theseinspections haveindicated thatdegradation intheupperinternals isaslowprogressing phenomena.

Basedonminimaldegradation todateandthenearendoflifefortheseSGs,noexaminations wereperformed duringU1R97.SafetAssessment Thefollowing safetyconcernshavebeenpostulated byWOGrelativetotheFrenchSGinternals degradation experience.

~Lossofsupportinthetube.bundleleadingtowear,andpossibleprimary-to-secondary leakageorinadequate burstmargins.Increased TSPdeformation duringapostulated loss-of-coolant accident(LOCA)plussafeshutdownearthquake (SSE)'event,resulting inunacceptable SGtubecollapseorsecondary-to-primaryinleakage.

i~Generation ofalooseobjectinthesecondary sideofaSGthatmayresultintubewearorimpacting, andpossiblyprimary-to-secondary leakage.Asdiscussed below,industryexperience andvariousstandardpractices aretypically employedtoprovideassurance ofSGintegrity andnegatethepotential forthese'oncerns.

Asevidenced fromthepreviously discussed U1R97inspection results,ourunit1experiences andpractices mirrorthatoftheindustry.

Basedon'reviewofthetable1information, theonlydegradation typesthatmayoccurdomestically thatcouldresult,inthelossofTSPintegrity areTSPflowhole/ligament erosion-corrosion, TSPligamentcrackingnearthepatchplates,andTSPligamentcrackinginrandomareas.Thereisnoindustryevidenceofpost-chemical cleaninginspections indicating.

significant materialloss,noris'thereevidenceofanywrapperhavingdropped.WhileTSP'ligament crackinghasoccurredinunitswithcarbonsteel.supportplateswithdrilledroundholesandflowholes,thereisnoevidenceindicating TSPligamentcrackingorthinningthatisprogressive andcontinuing.

Utilities withseries51SGswithcarbon'steelsupportplatesinspectasignificant percentage ofSGtubeseveryoutagewithabobbincoilprobe(unit1inspects100%).Ifsectionsofthetubesupportweremissing,itwouldbereadilydetectable becauseofalackofeddycurrent.responseattheTSPelevation.

Thereisnoincreased susceptibility toligamentcrackingnearthewedgesupportsintheseries51SGdesign.Eithertherearenoflowholesextending totheperiphery

'atthewedgelocations, or=.thewedgesarenotweldedtotheTSPs,asisthecasewiththeEdF51MSG.Existingcalculations evaluating theeffectsofLOCAplusSSEloadingsonthetubebundlecontinuetoapplyindetermining whethercertaintubesshouldbeexcludedfromapplication ofthevoltagebasedpluggingcriteria, orwhethercertaintubesshouldberemovedfromserviceinplantsthatdonotcurrently havethecriteria, butmayhaveSGtubesexperiencing

~crackingatTSPintersections.

Attachment toAEP:NRC:1166AM Page6Anotheroccurrence resulting fromSGinternaldegradation thatmay.affectaSGinperforming itsintendedsafetyfunctionisthepotential fortubewearandprimary-to secondary leakageduetothegeneration ofalooseobjectonthesecondary sideoftheSG.Thismayoccurduetoerosion-corrosion ofthemoistureseparators, feedring/J-nozzle, orTSPflowholes,ortheoccurrence ofTSPligamentcracking.

Ifprimary-to-secondary leakageshouldoccurbecauseoftubewearfromalooseobject,theexpectedconsequences wouldbeboundedbyasingletuberuptureeventand,therefore, wouldremainwithinthecurrentlicensing basisoftheplant.Itisourpositionthatlooseobjectsshouldberemovedwheneverpossible.

Tubesobservedtohavevisibledamageareeddycurrentinspected andpluggedasnecessary.

ElementsoftheSGprogram,includi'ng eddycurrentinspection, foreignobjectsearchandretrieval duringeachrefueling outage,andloosepartsmonitoring areinplacetohelpensurethemaintenance oftubeintegrity duringplantoperation.

Becausenointernals degradation ofconsequence hasbe'enobservedontheunit1SGs,itisexpectedthat,neartermdegradation wouldbelimitedinextent,suchthat'thetubeswillremaincapableofsustaining theconditions ofnormaloperations, including operational transient, designbasisaccidents, externalevents,andnaturalphenomena, permitting theaffectedSGtoperformitssafetyfunction.

Inservice InsectionPlanBecauseof.thependingSGreplacement, itisprojected thattheunit1SGswillundergoonlyonemoreinspection priortothereplacement outage.Basedonthepreviousdiscussions, theupcominginspection planwillcloselymirroractivities performed in1997.Theplannedworkscope issummarized asfollows.A100%CDSscanwillbeperformed onthebobbincoildatafor.evidenceofsupportplate/ligament damage.Indication disposition willbebyMRPCprobe.Notethatthebobbincoilexamination willbeperformed on100%ofthein-service tubing.Foreignobjectsearchandretrieval operations willbeperformed ineachSGtoaccessthetubingandsupportstructure conditions aswellasverifythesludgeconditions withintheSGs.Accessible tubesheet surfacesandtubesatthetopofthetubesheet willbetargetedduringtheinspection.

Duringsludgelanceoperations tobeperformed ineachSG,itwillbeverifiedthatthelancingequipment canbeinsertedwithoutinterference.

Successful installation willprovideverification ofwrapperintegri.ty.

Ifinterference isdetected, thelowerwrappersupportblockswillbevisuallyinspected.

Thewrapperblock'inspection willalsobeconducted ifanyevidenceoftubedamageintheperiphery ofthefirstTSPisdetected.

Inspections willbeperformed onthefirstanduppermost TSPofoneSGtoassessfoulingconditions andidentifyanyevidenceofcorrosion ordamage.

~~Attachment toAEP:NRC:1166AM Page7Basedonsiteinspection experience, noupper-bundleinspections areplannedduringtheupcominginspection.

Shouldtheunit.1SGsbereplacedduringthenextoutage,ourinspection planwillberevisedappropriately.

-UNIT2SGPROGRAMINTERNALS INSPECTION SGDescritionIn1989,thefouroriginalunit2Westinghouse series53.SGswerereplacedwithWestinghouse series54FSGs.Keydesignfeaturesofthereplacement SGs.includethermally treatedalloy690tubing,afulldepthhydraulic expansion atthetube-to-tubesheet

'joint,quatrefoil stainless steelsupportplates,.increased row1U-bendradius,andheattreatedlowrowU-bends.ThenominaltubeODis0.875inches,withanominalwallthickness of0.050inches.RelatedIndustrFindinsAsdiscussed inWCAP-15002, revision1,twelveplantswithseriesD,E,44F,andFSGssuppliedinformation totheWOGconcerning resultsofSGsecondary sideinspections andrelevanttubeinspections forTSPconditions.

Forthemost,part,thefindingsdidnotreportdetection ofseveralmodesofdegradation experienced intheEdFunits.Thereisnoevidenceofpost-chemicalcleaninginspections indicating significant materialloss,.noristhereevidenceofanywrapper,havingdropped.WhileTSPligamentcrackinghasoccurredinunitswithcarbonsteelsupportplateswithdrilledroundholesandflowholes,thereisnoevidenceindicating TSPligamentcrackingorthinningthatisprogressive andcontinuing.

Thefollowingtablesummarizes theapplicable WOGconclusions concerning thesusceptibility ofSGsliketheunit2series54FSGs.tosecondary sideinternals degradation.

TABLE2DEGRADATION TYPELEVELOFSUSCEPTIBILITY ErosionCorrosion:

MoistureSeparator TSPFlowHole/Ligaments FeedRing/8-Nozzles Cracking:

TSPLigaments

      • WrapperNearSupports*+Other:NAWrapperDrop**

Attachment toAEP:NRC:1166AM Page8XLNA~*aobservedinsomeSGslowsusceptibility notapplicable variousindication ofdegradation maybeartifacts ofmanufacturing relatedtopatchplateplugweldsand/ordrillingalignment variousWestinghouse

.designfeatures'arebeneficial relativetosomeoftheSGdesignfeaturesofforeignmanufacturers Site-SecificFindinsTheunit2SGswerelastinspected inthefallof1997.Inadditiontothestandardeddy"currenttubei.nspection, othermeasureswereperformed toassuretheintegrity oftheSGinternals.

Theseinspections, coupledwithrelatedfindingsfrom'revious inspections anddesignattributes oftheunit2series54FSGs,demonstrate

.,thattheareasofinterestas,noted"intable2havebeenaddressed withnoabnormalconditions noted.Thefollowing discussion presentstheinternals inspection scopeandfindingsfortheunit21997refueling outage(U2R97).Thefollowing activities wereperformed ineachSG(unlessotherwise noted)duringtheU2R97foreignobjectsearchandretrieval operations.

~Pre-sludge LanceInspection

-Avisualinspection wasperformed toidentifythetubing/sludge, conditions atthetubesheet priortolancing.Thisinspection includedtheannulusanddividerlane.Post-Lance Inspection

-Avisualinspection wasperformed toverifytheeffectiveness ofthesludgeremovalprocessandthegeneraltubesheet/tubing conditions onthetopofthetubesheet.

Areasreviewedconsisted oftheannulus,dividerlaneandaninnerbundlepass.onboththehot.andcoldlegsides.~Sixthand'Seventh TSP.(OneSG)-Avisualinspection reviewedthesixthandseventhTSPstoaccesssludgeconditions andfoulingconditions intheupperregionoftheoneSG.Thepre/post-lance inspection confirmed theeffectiveness ofthesludgeremovaloperations andthegeneralcondition ofthetubingat'hetubesheet.

No,,degradation orsignsofabnormalities werenotedduringtheinspection.

Theuppersupportplateinspection notednosignsofdamagedcomponents ordegradation.

Regarding TSPdamage.orligamentcracking, eddycurrentassessments werenotperformed becausethequatrefoil broachedholesupportplatedesignmakesthistechnique notapplicable fordetecting damage.Noabnormalities weredetectedinthisareaduringtheforeignobjectsearchandretrieval operations thatwouldsuggestdamageofthisnature.Ingeneral,erosion-corrosion induceddegradation isviewedasalowsusceptibility eventbecausetheplatesareconstructed ofstainless steel.Specificinspection ofthewrapperbarrelareawasnotperformed.

However,wrapperconditions didnotaffecttheinstallation ofthe Attachment toAEP:NRC:1166AM Page9sludgelancingequipment thatwasperformed ineachSG.Therefore, itwasconcluded thatthewrapperhadnotslippedormoved.Whilenoinspections wereperformed duiingU2R97,on, theupperinternals, previousinspections havebeenperformed.

Duringthe1994inspection, tenJ-nozzles andthefeedringteesectionofoneSGwereinspected.

Noerosionwasnotedduringtheinspection.

Theoriginal, feedrings/J-nozzles werereplacedwhentheunit2SGswerereplacedin1989.Thereplacement feedrings areconstructed ofextrastrongcarbonsteelandtheJ-nozzles aremade.from,alloy600,whichislesssusceptible toerosiondamagethan.thetypicalcarbonsteelJ-nozzles.

Theseinspections indicatethatdegradation intheupperinternals isaslowprogressing phenomena.,

Basedonminimaldegradation to-date,noexaminations werescheduled'for U2R97.SafetAssessment Asnotedintheunit1safetyassessment, thefollowing safetyconcernshavebeenpostulated bytheWOGrelativetotheFrenchSGinternals degradation experience.

~>>Lossofsupportleadingtowearandpossibleprimary-to-secondary leakageorinadequate burstmargins..Moresignificant TSPdeformation duringapostulated LOCAplusSSEevent,resulting inunacceptable SGtubecollapseorsecondary-to-primary inleakage.

Generation ofalooseobjectinthesecondary sideofaSGwhichmayresultintubewearorimpacting andpossiblyprimary-to-secondary leakage.Asdiscussed below,design.features, industryexperience, andvariousstandardpractices aretypically employedto-provideassurance ofSGintegrity andnegatethepotential fortheseconcerns.

Previously discussed U2R97inspection resultsindicateourunit2experiences andpractices aresimilartothatoftheindustry.

Basedonareviewofthetable2information, theonlydegradation typesthatmayoccurdomestically thatwouldlikelyresultinthelossofTSPintegrity areTSPflowhole/ligament erosion-corrosion, TSPligamentcrackingnearthepatchplates,andTSPligamentcrackinginrandomareas.Thereisnoindustryevidenceofpost-chemicalcleaninginspections resulting inthediscovery ofanysignificant materialloss,noristhere.evidence ofanywrapperhavingdropped.NoTSPligamentindications havebeenfoundinsteamgenerators withstainless steelTSPs.Thispopulation includestheunit2SGs.Noincreased susceptibility toligamentcrackingnearthewedgesupportshasbeenidentified intheseriesD,E,44F,andF(unit.2)SGsdesigns.Existingcalculations evaluating theeffectsofLOCAplusSSEloadingsonthetubebundlecontinuetoapplyindetermining whethercertaintubesshouldbeexcludedfromapplication ofthevoltagebasedpluggingcriteria, orwhethercertain.tubesshouldberemovedfromserviceinplantsthatdonotcurrently haveacriteriabutmayhaveSGtubesexperiencing crackingatTSPintersections.

Attachment toAEP:NRC:1166AM Page10Anotheroccurrence resulting fromSGinternaldegradation thatmayaffectaSGinperforming itsintendedsafetyfunctionisthe"potential fortubewearandprimary-to-secondary leakageduetothegeneration ofalooseobjectonthesecondary sideoftheSG.Thismayoccurbecauseoferosion-corrosion ofthemoistureseparators ortheoccurrence ofTSPligamentcracking.

Ifprimary-to-secondary leakageshouldoccurduetotubewearfromalooseobject,theexpectedconsequences wouldbeboundedbyasingletuberuptureeventandwouldremainwithinthecurrentlicensing basisoftheplant.Itisourpositionthatlooseobjectsshouldberemovedwheneverpossible.,

Tubesobservedtohavevisibledamageareeddycurrentinspected andpluggedasnecessary.

ElementsoftheSGprogram,including eddycurrentinspection, foreignobjectsearchandretrieval duringeachrefueling outage,andloosepartsmonitoring areinplacetohelpensurethemaintenance oftubeintegrity duringplantoperation.

Becausenointernals degradation ofconsequence hasbeenobservedontheunit2SGs,itisexpectedthatfuturedegradation wouldbelimitedinextentsuchthatthetubeswillremaincapableofsustaining theconditions ofnormaloperations, including operational transient, designbasisaccidents, externalevents,andnaturalphenomena, permitting theaffectedSGtoperformitssafetyfunction.

Basedontheabove,implementation ofthefollowing inspection planisplannedontheunit2SGstoaddressthevarioustypesofSGsecondary sideinternals degradation thatmayoccurinWestinghouse-designed SGs.Thisplanmaybeamended,pendingtheresultsofadetailedindustryevaluation thatisexpectedtobecompleted bymid-1998.

Inservice InsectionPlanGiventheprimarysideeddycurrent,inspection resulting inaC-1classification andtheabsenceofsecondary sidefindingsduringthelastinspection, noinspection activities areplannedattheendofthecurrentcycle(cycle12).Inspection scopeforthesubsequent outagehasnotbeenfinalized.

However,ataminimum,plannedsecondary sideinspections willbesimilartothoseperformed in1997.Theplannedworkscope issummarized asfollows.Foreignobjectsearchandretrieval operations willbeperformed ineachSGtoaccessthetubingandsupportstructure conditions aswellasverifythesludgeconditions withintheSGs.Accessible tubesheet surfacesandtubesatthetopofthetubesheet willbetargetedduringtheinspection.

Duringsludgelanceoperations tobeperformed ineachSG,itwillbeverifiedthatthelancingequipment canbeinsertedwithoutinterference.

Successful installation willprovideverification ofwrapperintegrity.

Ifinterference isdetected, thelowerwrappersupportblockswillbevisuallyinspected.

Thewrapperblockinspection willalsobeconducted ifevidenceoftubedamageintheperiphery ofthefirstTSPisdetected.

Inspections willbeperformed onthefirstanduppermost TSPofoneSGtoassessfoulingconditions andidentifyevidenceofcorrosion ordamage.

I11a Attachment to.AEP:NRC:1166AM Page11Toverifyconditions intheupperbundlearearemainconsistent withpastinspections, an.inspection willbeperformed onthemoistureseparator unitsandapopulation ofJ-nozzles andthefeedringteeareaofoneSG.CONCLUSIONS Theaforementioned inspection programsare,basedonindustryexperience andoursite-specific inspection findings.

Webelievetheseprogramsareofanaturetoadequately addressconcernsofinternals degradation asnotedinGL97-06.