ML17165A409

Three Mile Island Nuclear Station, Unit 1 - T1R22 Refuel Outage MRP-227-A Reactor Internals Scope Deferral Review

ML17165A409
Person / Time
Site:	Three Mile Island
Issue date:	06/14/2017
From:	David Helker Exelon Generation Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
TMl-17-059
Download: ML17165A409 (19)

Text

Exelon Generation 10 CFR 54 TMl-17-059 June 14, 2017 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555 Three Mile Island Nuclear Station, Unit 1 (TMI) Renewed Facility Operating License No. DPR-50 NRC Docket No. 50-289

Subject:

T1 R22 Refuel Outage MRP-227-A Reactor Internals Scope Deferral Review

References:

(1) TMl-12-069, "Submittal of Inspection Plan for Reactor Internals," dated April 16, 2012 (2) Letter, Meena K. Khanna, Chief, Plant Licensing Branch 1-2 to Michael J. Pacilio, President and Chief Nuclear Officer, Exelon Nuclear, "Three Mile Island Nuclear Station, Unit 1 -Staff Assessment of the Reactor Vessel Internals Inspection Plan (TAC NO. MF1459)," dated December 19, 2014 In Reference 1 TMI provided the Inspection Plan for TMI Reactor Vessel Internals in accordance with License Renewal Activity No. 36 of Appendix A of NUREG-1928, "Safety Evaluation Report Related to the License Renewal of Three Mile Island Nuclear Station, Unit 1," dated October 2009, and MRP-227-A, "Materials Reliability Program: Pressurized Water Reactor Internals Inspection and Evaluation Guidelines (MRP-227-A)," dated December 2011. In Reference 2 the U.S. Nuclear Regulatory Commission (NRC) reviewed the TMI Inspection Plan for Reactor Vessel Internals (RVI) and concluded that the licensee's RVI Inspection Plan was acceptable because it was consistent with the inspection and evaluation guidelines of MRP-227-A, the licensee had addressed six of the eight licensee action items specified in MRP-227-A appropriately, and had made regulatory commitments to submit analyses fulfilling the other two action items on an acceptable schedule. TMI has elected to delay implementation of the final scope of RVI MRP-227-A examinations from the T1 R22 (2017) refueling outage to the T1 R23 (2019) refueling outage. Per the requirements of MRP-227-A, these "needed" examinations are to be U.S. Nuclear Regulatory Commission T1 R22 Refueling Outage MRP-227-A Reactor Internals Scope Deferral June 14, 2017 Page 2 completed no later than two refueling outages from the beginning of the license renewal period or during the next 10-year ISi interval. T1 R22 (2017) is the second refueling outage after entry into the period of extended operation (April 2014). The examinations are being rescheduled due to the economic uncertainty surrounding the continued operation of TMI. On May 30, 2017, Exelon announced that it will prematurely retire TMI on or around September 30, 2019, absent needed policy reforms. In light of this decision and based on the industry experience from performing the required examinations, Exelon has evaluated the remaining MRP-227-A examinations scheduled for the T1 R22 refueling outage and determined that it is technically justifiable to defer the examinations to the following T1 R23 refueling outage. Attachment 1 provides a revised commitment. The remaining commitments in Reference 1 remain unchanged. Attachment 2 provides the Exelon Materials Degradation Management Process (MDMP) Deviation Form. Attachment 3 provides the Technical Evaluation 04020993-02, TMI MRP-227-A Inspection Deviation-T1 R22. Should you have any questions concerning this submittal, please contact Frank Mascitelli at 610-765-5512. Respectfully, David P. Helker Manager, Licensing & Regulatory Affairs Exelon Generation Company, LLC Attachments: 1) 2) 3) Summary of Regulatory Commitments Exelon Materials Degradation Management Process (MDMP) Deviation Form Technical Evaluation 04020993-02, TMI MRP-227-A Inspection Deviation-T1 R22. cc: USNRC Regional Administrator, Region I USNRC Project Manager, TMl-1 USNRC Senior Resident Inspector TMl-1 Director, Bureau of Radiation Protection -PA Department of Environmental Resources Chairman, Board of County Commissioners of Dauphin County, PA Chairman, Board of Supervisors of Londonderry Township, PA R. R. Janati, Commonwealth of Pennsylvania ATTACHMENT 1 SUMMARY OF REGULATORY COMMITMENTS The following table identifies commitments made in this document. (Any other actions discussed in the submittal represent intended or planned actions. They are described to the NRC for the NRC's information and are not regulatory commitments.) COMMITMENT TYPE COMMITMENT COMMITTED DATE One-Time Programmatic OR "OUTAGE" Action (Yes/No) {Yes/No) Yes No TMI will complete the deferred MRP-T1 R23 (2019) refueling 227-A inspections (described in outage. Attachment 2 of TMl-17-059 letter to NRC) during the T1 R23 (2019) refueling outage.

ATTACHMENT 2 EXELON MATERIALS DEGRADATION MANAGEMENT PROCESS (MDMP) DEVIATION FORM ERAA4003Attachment2MDMPDeviationFormPage1of2Utility:ExelonApplicableSite(s)andUnitNo.:ThreeMileIslandUnit1UtilityContact(s):RossShacklett/MarkTorborg,TMIEngineeringPrograms,HeatherMalikowski,CorporateAssetManagementIssueProgram(IP)activityordocument:MaterialsReliabilityProgram:PressurizedWaterReactorInternalsInspectionandEvaluationGuidelines(MRP227A)Scope/DescriptionofDeviation:TMIhaselectedtodelayimplementationofthefinalscopeofReactorVesselInternalsMRP227Aexaminationsforonerefuelingoutage(fromT1R222017toT1R232019).PertherequirementsofMRP227A,the"needed"examinationsshallbecompletednolaterthantworefuelingoutagesfromthebeginningofthelicenserenewalperiodorduringthenext10yearISIinterval.T1R22(2017)isthesecondrefuelingoutageafterentryintotheperiodofextendedoperation(April2014).ThroughcorrespondencewiththeNRC,approvedonDecember19,2014(ML14297A411),ExelonstatedthatexaminationofRVIcomponentsthatareaccessibleonlywhiletheCoreSupportAssembly(CSA)isremovedwillbeperformedduringthe2015refuelingoutage(RFO),andthatotherRVIcomponentswillbeexaminedduringthe2017RFO.DuringrefuelingoutageT1R21,(October2015)ExelonsuccessfullyexecutedapartialimplementationoftheMRP227Aexaminations.CompletedMRP227AInspections-T1R21ComponentExamTypeUpperCoreBarrelBoltsandLockingDevicesUTLowerCoreBarrelBoltsandLockingDevicesUTFlowDistributorBoltsandLockingDevicesUTLowerGridAssemblyAlloyX750DoweltoguideBlockWeldsVT3LowerGridShockPadBoltingandLockingDevices(proactiveaugmentedexam)UT&VT3Theremainingexaminations,originallyscheduledforT1R22,beingdelayeduntilT1R23arelistedbelow.RemainingMRP227AInspectionsComponentExamTypePlenumWearPads(WeldmentRibPads)VT3PlenumCoverSupportFlangeVT3ControlRodGuideTube(CRGT)spacercastingsVT3CSSventvalvetop&bottomretainingringsVT3BaffletoformerboltsUTLockingDevices,includingLockingWelds,ofBaffletoFormerBoltandInternalBaffletoBaffleBoltsVT3BaffleplatesVT3IMIguidetubespidersVT3IMIguidetubespidertolowergridribsectionweldsVT3 ERAA4003Attachment2MDMPDeviationFormPage2of2ReasonforDeviation:TheexaminationsarebeingrescheduledduetotheeconomicuncertaintysurroundingthecontinuedoperationofThreeMileIslandUnit1.OnMay30,2017,ExelonannouncedthattheywillprematurelyretireThreeMileIslandGeneratingStationonoraroundSeptember30,2019,absentneededpolicyreforms.Inlightofthisdecisionandbasedontheindustryexperiencefromperformingtherequiredexaminations,ExelonhasdetermineditisnotprudenttoperformtheremainingMRP227AexaminationsduringT1R22andistechnicallyjustifiabletodefertheexaminationstothefollowingrefuelingoutage,T1R23.ReferencetheEClistedbelowforadditionaltechnicalevaluation.IRNumber:04020993ECNumber:0402099302TimeFrametheDeviationwillbeinEffect:ThisdeviationwillbeineffectuntilrefuelingoutageT1R23(2019)orTMI1retirementin2019.DeviationfromthisIPdocumentisclassifiedas:NEEDEDTheonlyNEI0308recommendationinMRP227Athatwouldnotbemetis"Needed"item7.3,ReactorInternalsGuidelinesImplementationRequirement."EachcommercialU.S.PWRunitshallimplementTables41through49andTables51through53fortheapplicabledesignwithintwentyfourmonthsfollowingissuanceofMRP227A."PreparedBy:RossShacklettDate:StationProgramManager:MarkTorborgDate:SiteEngineeringDirector:BlairWunderlyDate:CorporateMDMPOwner:HarryL.SmithDate:CorporateAssetManagementManager:JamesCirilliDate:CorporateProgramsDirector:ThomasBassoDate:SiteVicePresident:EdwardCallanDate:SeniorVPofEngineering&TechnicalServices:ScotGreenleeDate:

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• j 9rr; 1."..i; :.l, *G*b 1 ":W :h \* tnir...; "'11:: !: p ;rfo(rr*ir.!1' ."PUl ... *;*d ; .. it b p1;!io:rn *!-':i.::* "*.;::u":-.. *'.-::: .-!-, r ..... '? dnd Tl:**,.;:*.*;_ ti::i"lC1:;. EC .. fL"'.lr 1'fn1E t..:.r.H i:J 'Nil;!*.:: *. in er ... H<t ln ,...i-!c. :.1nh* 03*)S ::: S\...1f'-:P ... \..*.'uuirJ Hr (i°r,r ; .1t:i*1 !J.S. P\\IR s:\l).!f t1i:'f}t 4 *9 \HJd 5<r. 1 Oi1rHi:.::t1i*.! \ .. !!rt 1\.".':*: iH.y-*:-.:JlJ:-rr:r. n1i= i$:'it::nct:: 1.:f 1\1H?fl-.l2 7 :--*!:t*11iff '?:. Fur Scott Greenlee l /, 3f1'7_ 06/13/17 ATTACHMENT 3 TECHNICAL EVALUATION 04020993*02 TMI MRP-227-A INSPECTION DEVIATION-T1R22.

TMIMRP227AInspectionDeviation-T1R22TechnicalEvaluation0402099302Page1of111.ReasonForEvaluation/Scope:TMIhaselectedtodelayimplementationofthefinalscopeofMRP227Aexaminationsforonerefuelingoutage,fromT1R22in2017toT1R23in2019.TheexaminationsarebeingrescheduledduetotheeconomicuncertaintysurroundingthecontinuedoperationofThreeMileIslandUnit1.OnMay30,2017,ExelonannouncedthattheywillprematurelyretireThreeMileIslandGeneratingStationonoraroundSeptember30,2019,absentneededpolicyreforms.PertherequirementsofMRP227A,the"needed"examinationsshallbecompletednolaterthantworefuelingoutagesfromthebeginningofthelicenserenewalperiodorduringthenext10yearISIinterval.T1R22(2017)isthesecondrefuelingoutageafterentryintotheperiodofextendedoperation(April2014).ThroughcorrespondencewiththeNRC,approvedonDecember19,2014(ML14297A411),ExelonstatedthatexaminationofRVIcomponentsthatareaccessibleonlywhiletheCoreSupportAssembly(CSA)isremovedwillbeperformedduringthe2015refuelingoutage(RFO),andthatotherRVIcomponentswillbeexaminedduringthe2017RFO.DuringrefuelingoutageT1R21(October2015),ExelonexecutedapartialimplementationoftheMRP227Aexaminations(componentsonlyaccessiblewhiletheCoreSupportAssembly(CSA)isremoved).Theremainingexaminations,originallyscheduledforT1R22andbeingdelayeduntilT1R23arelistedbelow.AllotherMRP227ArequiredexamswerecompletedinT1R21(2015):RemainingMRP227AInspectionsComponentExamTypePlenumWearPads(WeldmentRibPads)VT3PlenumCoverSupportFlangeVT3ControlRodGuideTube(CRGT)spacercastingsVT3CSSventvalvetop&bottomretainingringsVT3BaffletoformerboltsUTLockingDevices,includingLockingWelds,ofBaffletoFormerBoltandInternalBaffletoBaffleBoltsVT3BaffleplatesVT3IMIguidetubespidersVT3IMIguidetubespidertolowergridribsectionweldsVT3ThisevaluationwilldeterminetheacceptabilityofdelayingtheremainingMRP227A"needed"examinationsbyonerefuelingoutage(fromT1R22in2017toT1R23in2019).2.DetailedEvaluation:ThefollowingcomponentexaminationsareneededtofulfilltheMRP227Areactorinternalsprimaryexaminationrequirements.AllotherMRP227ArequiredexamswerecompletedinT1R21(2015).OperatingExperiencefromOconee1,2,3andArkansasNuclearOne1MRP227Aexaminationswasreviewedforrelevantfindings.Oconee1,2,3andArkansasNuclearOne1shareasimilarB&WReactor TMIMRP227AInspectionDeviation-T1R22TechnicalEvaluation0402099302Page2of11VesselInternaldesignandaccountforfourofthesixoperatingB&Wsites.ThreeMileIslandandDavisBessehavenotcompletedtheMRP227AexaminationandaccountfortheremainingtwoB&Wsites.Foragecomparison,TMI1willbeatapproximately32.2EFPYduringT1R22and34.00EFPYduringT1R23.Oconee1wasat30.61EFPY,Oconee2wasat31.82EFPY,Oconee3wasat31.67EFPY,andANO1wasat32.403EFPYwhenMRP227Ainspectionswereperformed.WhiletheestimatedEFPYforTMI1performingMRP227AexamsinT1R23isgreaterthantheotherB&Wunitsbyapproximately1.53.5EFPY,alloftheexaminationfindingsatthesesitesallowedfora10yearreinspectioninterval.ThereforethereislowriskthatwaitinganotherfuelcycletocompletetheMRP227Aexaminationswouldallowsignificantagingdegradationtodevelopthatwouldbeconsideredunacceptableforcontinuedservice.NoTMI1specifichistoricaloperatingpracticesordesigndifferenceswereidentifiedthatwouldcauseconcernforhavingworsefindingsthantheotherB&Wunits.2.1PlenumWearPads(WeldmentRibPads)2.1.1NEI0308InspectionRequirementsTheNEI0308inspectionrequirementsforthePlenumWearPads(WeldmentRibPads)arecomprisedof1)aonetimephysicalmeasurementtodeterminethedifferentialheightofthetopofplenumribpadstoreactorvesselseatingsurface,withtheplenuminthereactorvesseland2)subsequentvisual(VT3)examinationonthe10yearISIinterval.Thisinspectionisintendedtoidentifylossofmaterialandassociatedlossofcoreclampingpreload(wear).2.1.2IndustryOPEXMRP227AinspectionreportsfromOconee1,2,3andArkansasNuclearOne1werereviewedforsignificantdiscoveries.NoservicerelateddegradationorrelevantindicationswerenotedduringtheMRP227AinspectionsofthePlenumWearPads(WeldmentRibPads)atanyofthesimilarunits.2.1.3TMIInspectionResultsCoreclampingmeasurementswereobtainedatTMI1byAREVAin2010tosatisfytheMRP227Aexaminationrequirementsforaonetimephysicalmeasurementofthedifferentialheightoftopoftheplenumribpadstothereactorvesselseatingsurface.Thismeasurementwastakenwiththeplenumcoverweldmentribpads,plenumcoversupportflange,andCSStopflangeinsidetheRV,butwiththefuelassembliesremovedperSection4.3.1ofMRP227A.Theconclusionsofthecoreclampingsummarydocumentarethattherewasnoevidenceofwearoccurringduringtheserviceperiodandthemeasurementswereacceptable.Therefore,thecoreclampingmeasurementsatTMI1meettheonetimephysicalmeasurementrequirementinMRP227A.(Reference4.3&4.4)2.1.4Conclusion TMIMRP227AInspectionDeviation-T1R22TechnicalEvaluation0402099302Page3of11Delayingthevisualinspection(VT3)ofthePlenumWearPads(WeldmentRibPads)byonecycleisacceptable.InspectionsatsimilarB&Wunitshavenotrevealedanyconcernswithmaterialcondition.PreviousTMIinspectionsdidnotidentifyevidenceofwearoccurring.Therefore,therearenotechnicalconcernswithdelayingthevisualinspection.2.2PlenumCoverSupportFlange2.2.1NEI0308InspectionRequirementsTheNEI0308inspectionrequirementforthePlenumCoverSupportFlangeisavisual(VT3)examinationonthe10yearISIinterval.Thisinspectionisintendedtoidentifylossofmaterialandassociatedlossofcoreclampingpreload(wear).2.2.2IndustryOPEXMRP227AinspectionreportsfromOconee1,2,3andArkansasNuclearOne1werereviewedforsignificantdiscoveries.NoservicerelateddegradationorrelevantindicationswerenotedduringtheMRP227AinspectionsofthePlenumCoverSupportFlangeatanyofthesimilarunits.2.2.3TMIInspectionResultsVisualinspectionsofthePlenumCoverSupportFlangethatmeetthescopeofMRP227Ahavenotbeenperformedpreviously.However,duringT1R22(2015),ASMESectionXIvisual(VT3)inspectionsofthePlenumCoverSupportFlangewereperformed.Theexamcovered360°oftheaccessiblesurfacesofthePlenumCoverSupportFlangeforwear(SectionXI).Therewerelimitationsduetothecavitywallconfiguration.ThebottomandtheinboardflangesurfaceswereexaminedinconjunctionwiththeClampingSurfacesandthePlenumCoverandRibattachmentsexaminations.Noservicerelateddegradationorrelevantindicationswerenotedduringthisinspection.(Reference4.5)2.2.4ConclusionDelayingthevisualinspection(VT3)ofthePlenumCoverSupportFlangebyonecycleisacceptable.InspectionsatsimilarB&Wunitshavenotrevealedanyconcernswithmaterialcondition.PreviousTMIinspectionsdidnotidentifyanydegradation.2.3ControlRodGuideTube(CRGT)SpacerCastings2.3.1NEI0308InspectionRequirementsTheNEI0308inspectionrequirementfortheCRGTSpacerCastingsisavisual(VT3)examinationofaccessiblesurfacesateachofthefourscrewlocations(atevery90°)of100%oftheCRGTSpacerCastingsonthe10yearISIinterval.

TMIMRP227AInspectionDeviation-T1R22TechnicalEvaluation0402099302Page4of11Thisinspectionisintendedtoidentifycracking(thermalembrittlement),includingthedetectionoffracturedspacersormissingscrews.2.3.2IndustryOPEXMRP227AinspectionreportsfromOconee1,2,3andArkansasNuclearOne1werereviewedforsignificantdiscoveries.Noservicerelateddegradation,missingscrews,orrelevantindicationswerenotedduringtheMRP227AinspectionsoftheCRGTSpacerCastingsatanyofthesimilarunits.2.3.3TMIInspectionResultsVisualinspectionsoftheCRGTSpacerCastingsthatmeetthescopeofMRP227Ahavenotbeenperformedpreviously.However,duringT1R22(2015),ASMESectionXIvisual(VT3)inspectionsoftheaccessibleareasof69ControlRodGuideTubeAssemblieswereperformed.Theinspectionexaminedtheaccessibleareasofthecontrolrodguidestubesfromthetoplookingdown,aroundtheperipheryandthroughtheholesinthecylinder.Theinspectionidentifiedasmallflakeofforeignmaterialthatwaslikelyintroducedduringrefuelingactivitiesandwaseasilyretrieved.(Reference4.16)Nootherindicationswerenoted.(Reference4.5)AREVAhasnotedthatissueswithControlRodinsertiontimesareapotentialindicatorofissueswiththeCRGTSpacerCastings.RecentControlRodinsertiontimingduringT1R21didnotindicateanyissues.Therefore,itislesslikelyanissuewiththeCRGTSpacerCastingsexists.2.3.4ConclusionDelayingthevisualinspection(VT3)oftheCRGTSpacerCastingsbyonecycleisacceptable.InspectionsatsimilarB&Wunitshavenotrevealedanyconcernswithmaterialcondition.PreviousTMIinspectionsdidnotidentifyanydegradation.2.4CoreSupportShield(CSS)VentValveTop&BottomRetainingRings2.4.1NEI0308InspectionRequirementsTheNEI0308inspectionrequirementfortheCSSVentValveTop&BottomRetainingRingsisavisual(VT3)examinationof100%ofaccessiblesurfacesduringthe10yearISIinterval.Thisinspectionisintendedtoidentifycracking(thermalembrittlement),includingthedetectionofsurfaceirregularities,suchasdamaged,fracturedmaterials,ormissingitems.2.4.2IndustryOPEXMRP227AinspectionreportsfromOconee1,2,3andArkansasNuclearOne1werereviewedforsignificantdiscoveries.NosignificantmaterialdegradationormissingitemswerediscoveredduringtheMRP227AinspectionsoftheCSSVentValveTop&BottomRetainingRingsatanyofthesimilarunits.

TMIMRP227AInspectionDeviation-T1R22TechnicalEvaluation0402099302Page5of11ANO1identifiedsomerelevantindicationsontheoriginalandmodifiedlockingdevices.However,theseindicationsweredeterminedtobeacceptableforcontinuedserviceandnotinterferewiththeventvalvefunction.2.4.3TMIInspectionResultsVentvalvetestingandinspectionsarerequiredtobeperformedeachrefuelingoutage,perTechSpec4.16.ThisrequirementisfulfilledbytheTMl1ReactorInternalsVentValveInspectionandExerciseprocedure.Theaccessibleareasoftheventvalvearetypicallyinspected,includingthelockingdevices.Additionally,ventvalveoperationistestedthroughmanualactuation.Recentinspectionsin2015didnotidentifyanyissueswithventvalveretainingrings.However,ventvalveRCV144Awasreplacedduetoexternalimpactdamagetothepressureplateandlockingdevice.VentvalvelockingdeviceswereexaminedforallventvalvesTechSpecrequirementsandTMIspecificcommitmenttoMRP227AandPWROGinterimguidance.RCV144A(adjacenttothehotleg)wasfoundwithafailedlockingdeviceinwhichthespringretainerhadwornthroughthelockingcup.Thelockingcupandspringretainerwerefunctionalasfound,butanassessmentofoperabilityoverthenextcyclecouldnotbemade.Thedamagemechanismwasflowinducedwearandwasbelievedtooriginatein1R18afterexternalimpactfromthePlenum.Thisventvalvewasoftheoriginaldesign.(Reference4.6)RemainingventvalvesexhibitedimpactdamageonthelockingdevicesfromtheinstallationofthePlenum.Thisimpactdamagedidnotaffecttheabilityofthelockingdevicestoperformtheirdesignfunctions2.4.4ConclusionDelayingthevisualinspection(VT3)oftheCSSVentValveTop&BottomRetainingRingsbyonecycleisacceptable.InspectionsatsimilarB&Wunitshavenotrevealedanyconcernswithmaterialconditionoftheventvalveretainingrings.PreviousTMIinspectionsdidnotidentifyevidenceofservicerelatedcrackingormissingitems.FunctionaltestingwillcontinuetobeperformedinT1R22.Therefore,therearenotechnicalconcernswithdelayingthevisualinspection.2.5BaffletoFormerBolts2.5.1NEI0308InspectionRequirementsTheNEI0308inspectionrequirementfortheBaffletoFormerBoltsisabaselinevolumetricexamination(UT)of100%ofaccessibleboltsnolaterthantworefuelingoutagesfromthebeginningofthelicenserenewalperiod.Thisinspectionisintendedtoidentifycracking(IrradiationAssistedStressCorrosionCracking,IrradiationEmbrittlement,andOverload).

TMIMRP227AInspectionDeviation-T1R22TechnicalEvaluation0402099302Page6of112.5.2IndustryOPEXBaffletoFormerBoltUTexaminationshavebeenofconcernwiththerecentinspectionresultsfromseveralWestinghouse4loopdownflowunits.AREVAissuedaCustomerServiceBulletin(CSB)1602inresponsetoWestinghouseNSAL161.CSB1602concludedthattheOEislimited,atthistime,toasubsetofdesignandoperatingconditionsfortheWestinghouse4loopdownflowoperatingunitsandnotanimmediaterisktothesafetyandoperabilityoftheB&Wdesigned177FAunits.Oconee1sharesasimilarboltdesignwithTMI1.MRP227Ainspectionreportswerereviewedforsignificantdiscoveries.Noservicerelateddegradation,relevantindications,ormissing,nonfunctional,orremovedlockingdevicesorweldswerediscoveredduringtheOconee1MRP227Ainspections.OtherB&Wunits(ANO1,Oconee2&3)haveadifferentboltdesignbutsimilaroperatingconditions.TheseexamresultsprovidefurthersupportinginspectiondatathattheissueisnotaconcernforB&Wunits.BasedupontheoperatingexperienceandconclusionsfromtheAREVACSB,thereislowriskfordelayingtheexamatTMI.2.5.3TMIInspectionResultsVisualinspectionsoftheBaffletoFormerBoltswereperformedinT1R21(2015).Theseinspectionsdidnotidentifyanyservicerelatedmaterialdegradationissues.AlthoughthescopeoftheseinspectionsdidnotcovertheMRP227AscopeofUTinspections,novisualmaterialdegradationissueswerenoted.(Reference4.5)2.5.4ConclusionDelayingthebaselinevolumetricexamination(UT)oftheBaffletoFormerBoltsbyonecycleisacceptable.UTinspectionsatsimilarB&Wunitshavenotrevealedanyconcernswithmaterialcondition.PreviousvisualinspectionsatTMIdidnotidentifyanyservicerelateddegradationissues.Therefore,therearenotechnicalconcernswithdelayingtheUTinspectiononecycle.2.6LockingDevices,IncludingLockingWelds,ofBaffletoFormerBoltandInternalBaffletoBaffleBolts2.6.1NEI0308InspectionRequirementsTheNEI0308inspectionrequirementforlockingdevicesofbaffletoformerboltandinternalbaffletobaffleboltsisavisual(VT3)examinationof100%ofaccessiblebaffletoformerandinternalbaffletobaffleboltlockingdevicesduringthe10yearISIinterval.Thisinspectionisintendedtoidentifycracking(IrradiationAssistedStressCorrosionCracking,IrradiationEmbrittlement,andOverload),includingthedetectionofmissing,nonfunctional,orremovedlockingdevicesorwelds.

TMIMRP227AInspectionDeviation-T1R22TechnicalEvaluation0402099302Page7of112.6.2IndustryOPEXOconee1sharesasimilarB&WReactorVesselInternaldesignwithTMI1.MRP227Ainspectionreportswerereviewedforsignificantdiscoveries.Noservicerelateddegradation,relevantindications,ormissing,nonfunctional,orremovedlockingdevicesorweldswerediscoveredduringtheMRP227Ainspectionsofthelockingdevicesatanyofthesimilarunits.2.6.3TMIInspectionResultsVisualinspectionsofthebaffletoformerboltswereperformedinT1R21(2015).AlthoughthescopeoftheseinspectionsdidnotcoverthefullMRP227Ascope,noservicerelateddegradationissuesormissinglockingdeviceswerenoted.(Reference4.5)2.6.4ConclusionDelayingthevisualinspection(VT3)ofthelockingdevicesofbaffletoformerboltandinternalbaffletobaffleboltsbyonecycleisacceptable.InspectionsatsimilarB&Wunitshavenotrevealedanyconcernswithmaterialcondition.PreviousTMIvisualinspectionsofthebaffletoformerboltsdidnotidentifyevidenceofservicerelateddegradationissuesormissinglockingdevices.Therefore,therearenotechnicalconcernswithdelayingtheMRP227Avisualinspection.2.7Baffleplates2.7.1NEI0308InspectionRequirementsTheNEI0308inspectionrequirementforthebaffleplatesisavisual(VT3)examinationof100%oftheaccessiblesurfaceswithinoneincharoundeachflowandboltholeduringthe10yearISIinterval.Thisinspectionisintendedtoidentifycracking(irradiationembrittlement),includingthedetectionofreadilydetectiblecrackinginthebaffleplate.2.7.2IndustryOPEXMRP227AinspectionreportsfromOconee1,2,3andArkansasNuclearOne1werereviewedforsignificantdiscoveries.Noservicerelateddegradation,cracking,orrelevantindicationswerenotedduringtheMRP227Ainspectionsofthebaffleplatesatanyofthesimilarunits.2.7.3TMIInspectionResultsGeneralexaminationsofthebaffleplatesduringnormalrefuelingoutageshavenotidentifiedanymaterialdegradation.VisualinspectionsofthebaffleplatesthatmeetthescopeofMRP227Ahavenotbeenperformedpreviously.DuringT1R21(2015),visual(VT3)inspectionoftheaccessibleareasoftheCoreBarrelAssemblyFormerPlateswasperformed.TherewaslimitedaccessduetoUpperCSAFlangeandBafflePlates.Norelevantindicationsobserved.(Reference4.5)

TMIMRP227AInspectionDeviation-T1R22TechnicalEvaluation0402099302Page8of112.7.4ConclusionDelayingthevisualinspection(VT3)ofthebaffleplatesbyonecycleisacceptable.InspectionsatsimilarB&Wunitshavenotrevealedanyconcernswithmaterialcondition.PreviousTMIinspectionsdidnotidentifyevidenceofservicerelateddegradation.Therefore,therearenotechnicalconcernswithdelayingthevisualinspection.2.8IncoreMonitoringInstrumentation(IMI)GuideTubeSpiders2.8.1NEI0308InspectionRequirementsTheNEI0308inspectionrequirementfortheIMIGuideTubeSpidersisavisual(VT3)examinationof100%oftopsurfacesofthe52spidercastingsnolaterthantworefuelingoutagesfromthebeginningofthelicenserenewalperiod.Thisinspectionisintendedtoidentifycracking(thermalembrittlement,irradiationembrittlement),includingthedetectionoffracturedormissingspiderarms.2.8.2IndustryOPEXMRP227AinspectionreportsfromOconee1,2,3andArkansasNuclearOne1werereviewedforsignificantdiscoveries.NoservicerelateddegradationorfracturedormissingspiderarmswerenotedduringtheMRP227AinspectionsoftheIMIGuideTubeSpidersatanyofthesimilarunits.2.8.3TMIInspectionResultsVisualinspectionsoftheIMIGuideTubeSpidersthatmeetthescopeofMRP227Ahavenotbeenperformedpreviously.2.8.4ConclusionDelayingthevisualinspection(VT3)oftheIMIGuideTubeSpidersbyonecycleisacceptable.InspectionsatsimilarB&Wunitshavenotrevealedanyconcernswithmaterialcondition.Therefore,therearenotechnicalconcernswithdelayingthevisualinspection.

2.9IncoreMonitoringInstrumentation(IMI)GuideTubeSpidertoLowerGridRibSectionWelds2.9.1NEI0308InspectionRequirementsTheNEI0308inspectionrequirementfortheIMIGuideTubeSpidertoLowerGridRibSectionWeldsisavisual(VT3)examinationof100%ofspidercastingweldstotheadjacentlowergridribsectionnolaterthantworefuelingoutagesfromthebeginningofthelicenserenewalperiod.

TMIMRP227AInspectionDeviation-T1R22TechnicalEvaluation0402099302Page9of11Thisinspectionisintendedtoidentifycracking(irradiationembrittlement),includingseparationofspiderarmsfromthelowergridribsectionattheweld.2.9.2IndustryOPEXMRP227AinspectionreportsfromOconee1,2,3andArkansasNuclearOne1werereviewedforsignificantdiscoveries.NosignificantmaterialdegradationwasnotedduringtheOconee1&2MRP227Ainspections.Oconee3identifiedtwolinearindications,onelocatedjustbelowtheverticalweldtoeinthebasematerialofthelowergridandtheothercomingfromthetopofthecastingattheweldtoeandgoingdownwardintothecastingmaterial.ThelinearindicationinthelowergridmaterialisinarelativelylowstressareaanddoesnotresembleIGSCC.ANO1identifiedindicationsontheIMItubespidertolowergridribsectionweldswhichexceededthecriteriafortriggeringscopeExpansionperMRP227A.However,inreviewingtheresultswithANO,ANOconsideredthedeterminationasconservative,andnorepairsorreplacementswereneededtoaddressanyoftheinspectionfindings.TheexpansioncomponentsfortheIMItubespidertolowergridribsectionweldsarethelowergridfuelassemblysupportpaditems:pad,padtoribsectionwelds,AlloyX750dowel,capscrew,andtheirlockingwelds.ANO1examinedtheseitemsduringthelastrefuelingoutageaspartoftheASMESectionXIBN3VT3visualexaminationsandnoindicationswerefound.2.9.3TMIInspectionResultsVisualinspectionsoftheIMItubespidertolowergridribsectionweldsthatmeetthescopeofMRP227Ahavenotbeenperformedpreviously.TMIcompletedtheASMESectionXIBN3examinationsinT1R21(2015)andnorelevantindicationswerefoundinthisarea.Therefore,thereisnoconcernfortheexpansionitemifthePrimarycomponentisnotexaminedinT1R22.(Reference4.5)2.9.4ConclusionDelayingthevisualinspection(VT3)oftheIMItubespidertolowergridribsectionweldsbyonecycleisacceptable.InspectionsatsimilarB&Wunitshavenotrevealedanysignificantconcernswithmaterialcondition.PreviousTMIinspectionsforASMESectionXIBN3examinationsdidnotidentifyanymaterialconditionissueswiththeexpansionitemsfortheprimarycomponent(i.e.thelowergridfuelassemblysupportpaditems).Therefore,therearenotechnicalconcernswithdelayingthevisualinspection.3.Conclusion/Findings:DelayingtheremainingMRP227A"needed"examinationsbyonerefuelingoutageisacceptable.TherehavebeennosignificantdiscoveriesfromsimilarB&WplantsthathaveperformedtheMRP227A TMIMRP227AInspectionDeviation-T1R22TechnicalEvaluation0402099302Page10of11inspections.BasedonindustryOperatingExperience,previousTMIinspections,andthedurationofthedelay(onecycle),therearenotechnicalconcernswithdelayingtheMRP227Aexaminations.4.

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5.Approval:PreparedBy:RossShacklett(SeePassportforApproval)Date:CorporatePWRInternalsProgramOwnerReview:HeatherMalikowski(SeePassportforApproval)Date:IndependentReview:RobertMarcello(SeePassportforApproval)Date:StationProgramManagerApproval:MarkTorborg(SeePassportforApproval)Date: