ML18142A468

22 - NRC Cib Overview of Component Integrity Research Activities

ML18142A468
Person / Time
Issue date:	05/23/2018
From:	NRC/RES/DE
To:
Rezai A, NRR-DMLR 415-1328
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Download: ML18142A468 (14)

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Overview of Component Integrity Research ActivitiesIndustry/NRC Materials Programs Technical Information Exchange 1 1May23,2018ComponentIntegrityBranch DivisionofEngineeringOfficeofNuclearRegulatoryResearch Research Areas

• PointsofContact-RajIyengar,BranchChief,ComponentIntegrityBranch-RobertTregoning,SeniorLevelAdvisor*ResearchAreas-ReactorPressureVesselIntegrity-MarkKirk-PipingIntegrityPatrickRaynaud/SaraLyons-ProbabilisticFractureMechanics-PatrickRaynaud/MattHomiack-NondestructiveExamination-CarolNove-AdvancedNonlightWaterReactors(ANLWR)-RajIyengar/MattGordon/SaraLyons-ASMESectionXICoordination&50.55aRegulatoryGuideRulemaking-MichaelBenson/BruceLin 2 2 RPV Integrity

• Overview-Objective:*ConfirmthecontinuedoperatingintegrityoftheRPV(includingtheSLRperiod)*Assesstheaccuracyofformulaethatpredictfutureembrittlementstatesforvesselmaterials-Driver:UserneedfromNRR;AssistancerequestfromNRO;RARfromNRRfortraining;SupportofRGGIBinperiodicRGreviews(e.g.,RG1.99)-Collaboration:JAEA,JNRA*Ongoingactivities

-RPVEmbrittlement

• AssessmentofshallowflaweffectsonRPVintegrity*Predictionoffluencebeyondthebelt line*REAPmaintenanceandadditionofnewsurveillancedata-Codes&Standards:ASMESectionXI;ASTM-FinalizationofPTSregulatoryguide(RG1.230)andtechnicalbasisdocument(NUREG2163)3 3 08/15/2017RPVIntegritylRESFOBrief4 Accomplishment Highlight:Late Blooming Phases

• PossibleConcern:Possiblerapidembrittlementinlowcoppersteelswithhighnickel&manganese.MechanismnotaccountedforbyUSNRCpredictions.

• RESReview:Comprehensiveliteraturereview&surveillancedataassessmentdemonstrateLBPsarenot ofconcernforUSRPVs.-LevelofNi>1%postulatedforLBPoccurrence

-Steelalloys/conditionsofpossibleconcernlargelyabsentfromUSAfleet-Evidenceofdelayedacceleratedembrittlementislacking*CurrentStatus:Ongoingresearch(DOE,intl.)tobetterunderstandLBPs.Newdatasuggestsno"sudden"lateembrittlementandmuchsmallerTvaluesforUSAsteels.4 RPV Integrity Accomplishments and Path Forward

• Accomplishments

-TLRonRPVfluenceevaluationmethodologyforbeyondtheactivecoreregion-IndependentreviewofNuScalePowerPressureandTemperatureLimits(PTL)MethodologyreportforNRO*PathForward-SupportNROforNuScaleapplicationreview-Continuecodesandstandardssupport(ASTME10;ASMECCN830revision)5 5 Piping Integrity

• Overview-Objective:Develop/Enhanceanalyticalmethodsandtoolstoassessstructuralintegrityofreactorpipingsystems-Driver:NRRUserNeedRequest-Collaboration:EPRI,NEA/CSNI*Ongoingactivities

-Developmentofmodelingguidelinesforassessmentofweldresidualstress(WRS)effectsinassessmentofcomponentintegrity-Assessmentofresearchandindustryexperienceinpeeningofreactorcomponents

-ParticipationinASMEBoilerandPressureVesselCode,SectionXI-CoordinationofASMEBPVCodeCaseRegulatoryGuidestoincorporatebyreferenceinto10CFR50.55a-EvaluationofExtendedFiniteElementMethod(xFEM)forapplicabilityincrackgrowth(PWSCC)analyses 6 7OngoingActivity: ApplyingxFEMTechniquestoPWSCCGrowth*ApplicationofExtendedFiniteElementMethod(xFEM)topredictPWSCCcrackgrowthin3Dcomponentgeometries.

• ConventionalFEM:-Usesidealizedcrackshapeandgrowthmodel(semielliptical)

-Assumesplanar(2D)crackgrowth-Uses2DWRSprofileforcrackgrowthwhichispathdependentanduserdefined*xFEM:-Meshindependentanalysisofflaws-SIFcalculationofmultiplecracksshapeswithoutmajorchangestomodel-3Dcrackgrowthwithoutre meshing*ParticipationininternationaleffortonbenchmarkingofxFEMcapabilities.(OECD CSNI)

Piping Integrity Accomplishments and Path Forward

• Accomplishments

-DraftNUREGonWRSvalidation

-SectionXIStandardsCommitteeandExecutiveCommitteeparticipation

-IssueddraftRegulatoryGuidesforASMECodeCases,2009 2013and2015editionstoincorporatebyreferenceinto10CFR50.55a*PathForward-IssuefinalreportsonWRSvalidation-DevelopandimplementresearchplanforvalidationxFEM AanalysisforPWSCCpredictions

-ContinueASMESectionXIengagement

-PreparedraftRegulatoryGuidesforASMECodeCasesfor2017EditionoftheBoilerandPressureVesselCode 8 8 Probabilistic Component Integrity

• Overview-Objective:Developprobabilisticmethodstoensurestructuralintegrityofpipingsystems-Driver:NRRUserNeedRequest-Collaboration:EPRI,JNRA,JAEA,SSM,CNSC*Ongoingactivities

-SupportNRRintheacceptanceandapplicationofxLPRv2-DevelopmentofProbabilisticFractureMechanicsRegulatoryGuide-ContinueeffortonV&VofFAVORcode,maintenance,applications,development,andmodernization 9 9 Probabilistic Component Integrity Accomplishments and Path Forward

• Accomplishments

-xLPRverificationandvalidationtesting-xLPRcodetheoryandhands ontrainingprovidedtoNRCstaff-xLPRPWSCCinitiationmodelparameterdevelopment,confirmatoryanalyses,andvalidation

-Completeddraftreporton"IncreasingConfidenceinPFMAnalyses"-InitiatedworkonFAVORV&V,maintenance,andapplications

• PathForward-SupportNRRregulatoryacceptabilityreviewforxLPR-CompleteeffortstoensurepublicreleaseofxLPR-InitiatestudiesonleakbeforebreakapplicationswithxLPR-DevelopPFMDraftRegulatoryGuide,withNUREGtechnicalbasisdocumentandPFMpilotstudiestotestguidance-BringFAVORuptomodernstandards,adaptFAVORtosolveevolvingreactorpressurevesselissues 10 10 Non-Destructive Examination

• Overview-Objective:EvaluateeffectivenessandreliabilityofNDEtechniques

-Driver:NRRUserNeedRequest-Collaboration:EPRI,DOE,International

• Ongoingactivities

-CompletionofcomprehensivesummaryofNDEresearchonCASSandassessmentofstate of the artininspectingweldsinCASSmaterials-Assessmentofindustry'sCASSroundrobin(rigorous,statistically based)-Providetechnicalbasisforconducting,interpreting,andapplyingtheresultsofultrasonictesting(UT)Modeling-Assesstheeffectsofincompleteexaminationcoverage-AssessmentofhumanfactorsissuesinNDE-Supportcodes&standardsactivities(ASME-SectionXI)-Assessmentofinspectionsystemsforstoragecasks 11 11 ANLWR Materials and Component Integrity

• Overview-Objective:AssesstheperformanceneedsandissuesforstructuralmaterialstobeusedinadvancednonLWRs(ANLWRs);SupportthedevelopmentofaregulatoryframeworkformaterialsrelatedissuesforANLWRs-Driver:NRCVisionandStrategyonANLWRs*Strategy2:Acquire/developsufficientcomputercodesandtoolstoperformnonLWRregulatoryreviews*Strategy4:FacilitateindustrycodesandstandardsneededtosupportthenonLWRlifecycle*Ongoingactivities

-Identificationofregulatorygapsforsodiumfastreactorsandmoltensaltreactors,buildingonthepasteffortsforhightemperaturegasreactors-Assessmentofmaterials/componentintegrityissuesformoltensaltreactors(MSR)-Operationalexperiencecompendiaformaterials/componentintegrityissuesforsodiumfastreactors(SFR)andhightemperaturegasreactors(HTGR)-ParticipationinASMECodesandStandardsSectionsIIIandXIactivities 12 12 ANLWR Materials Accomplishments

• Technical gap assessment for materials/component integrity for molten salt reactors -ORNLDraft report summary:*Limited high-temperature creep data at the highest possible core outlet temperatures*Limited data on salt purity effects on coolant compatibility and performance

• Limited data and mechanistic understanding on irradiation degradation effects

• Operational experience compendia for sodium fast reactors (SFRs) and high-temperature gas reactors (HTGR) -EWC-

CommercialOver 100 OpEsources have been identified and reviewed for SFRs [Phenix, SuperPhenix, FFTF, EBR-II] and HTGRs [Fort St Vrain, Peach Bottom, AVR and THTR-300]*Weld design and quality are critical for SFRs*Thermal fatigue is much more significant in SFRs than LWRs

• Design flaws seem to dominate HT GRs, resulting in unexpectedly high temperatures, moisture and oxygen ingress, and "trapped" pebblesSeparate bilateral engagements with Office of Nuclear Regulation, UK; IRSN-France; and JAEA and JNRZ -Japan 13 13 ANLWR Materials Accomplishmentsand Path Forward

• Supportknowledgeanddataenhancementofenvironmentaleffectsonreactorcomponents(internals,piping,welds,coatings)athightemperatures.(corrosion,radiationeffects)*Develop/EnhancecomputationalcodesforcomponentintegrityapplicabletoANLWRs*Exploreopportunitiestoobtaininformation,data,andassessmenttoolsthroughdomesticandinternationalcollaboration

• Conductresearchactivitiestodeveloptechnicalbasestoresolvemajormaterialsrelatedissues 14 14