ML17341A062

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NextEra Energy Seabrook Presentation Slides - Seabrook Station ASR Methodology LAR: Structural Deformation - LAR 16-03, Methodology and Responses to Rais D2-D8 - for November 17, 2017, Public Meeting
ML17341A062
Person / Time
Site: Seabrook NextEra Energy icon.png
Issue date: 11/17/2017
From:
NextEra Energy Seabrook
To:
Office of Nuclear Reactor Regulation
Poole J C, NRR/DORL/LPLI, 415-2048
References
CAC MF8260, EPID L-2016-LLA-0007
Download: ML17341A062 (29)


Text

LAR16-03MethodologyandResponsestoRAIsD2-D8November17,2017SeabrookStationASRMethodologyLAR:StructuralDeformation 2ThefoundationforeverythingwedoaretheValuesandCorePrinciplesofourNuclearExcellenceModel 3*NextEraEnergySeabrook-KenBrowneLicensingManager-JeffSobotkaDesignEngineeringManager-EdCarleyEngineeringSupervisor-JaclynHulbertEngineer-ASRProgramOwner*SimpsonGumpertzandHeger-Dr.SaidBolourchiSeniorPrincipal-Dr.AndrewSarawitSeniorProjectManager*MPR-JohnSimonsGeneralManager 4OverviewofMethodologyDocument*Provides-AnalysisandevaluationapproachforallSeismicCategoryIstructuresandallstages.-Sufficientdetailsprovidedforconsistentapplicationandrepeatabilityforallthreestagesofanalyses.-AcceptancebasedonmeetingtheCodesofrecordassupplemented.-SupplementstotheCodeswithjustifications.-Monitoringparametersandthresholdlimits.-ActionswhenASRdeformationsapproachlimits.*Allowsknowledgeablestructuralengineerstoimplementmethodologyinaconsistentandrepeatablemanner.

5ASREvaluationProcessLicenseAmendmentRequestMethodologyDocumentStructuralAnalysis&EvaluationThresholdLimits*Stage1,2,and3analyses*Materialproperties*RepeatableprocessforStage1,2,and3analyses*Demandcalculations*ComplianttoACI318-71andASMECodeassupplemented*EstablishdesignmarginforpotentialfutureASRexpansionStructuresMonitoringProgram*Monitoringparametersandfrequency*Trending*Actionifapproachingthresholdlimits 6ContentsofMethodologyDocument*CharacteristicsandMeasurementofASR*LoadsandLoadCombinations*AnalysisApproach*AcceptanceCriteria*ASRThresholdLimitsandMonitoring*EvaluationforApproachingThresholdlimits 7LoadsandLoadCombinations*Loadsandfactoredloadcombinationsare-asdefinedinthecurrentUFSARand-supplementedbyLAR16-03toincludeASRloadsandloadfactors.*ASRloadfactorsprovidesafetymarginsconsistentwiththeoriginalcodesofrecord.

8FieldMeasurementsSustainedLoadsCracking*Iscrackingobserved?*Iscrackinglimitexceeded?*Stiffnessreductionduetoaxial,shear,and/orflexuralcracking.MomentRedistribution*LimittoACI318-718.6FactoredLoadsDemand-to-CapacityRatioAcceptanceCriteriaSupplementtoACI318-71*ConsiderationofASRloads*Codeacceptancecriteria*Shear-frictioncapacityformemberssubjectedtonetcompression*Acceptablereductioninflexuralstiffness*StiffnessreductionduetoaxialandshearcrackingEvaluationStageThreeEvaluationProcessCorrelationofAnalysistoFieldObservationsThresholdParameters&Limits*Expansion*In-planeexpansionmeasurements*DistributionofASR*Structuraldeformationmeasurements*StructuralcrackingStructuresMonitoringProgramFEAModelFieldObservationsConcreteBackfillPressure*StiffnessreductionduetoASRexpansionofunreinforcedbackfill*Backfillpressurereduction:*Nostructuralcracks/distress*Overburdenpressure*Confinementstrengthreduction 9MethodologyDocumentSummary*ProvidesdetailedanalysisapproachforallstagesofanalysesdescribedintheLAR16-03.*Allowsknowledgeablestructuralengineerstoimplementmethodologyinaconsistentandrepeatablemanner.

10RAI-D2Request-ProvideadetailedexplanationofhowtheStage3analysismethodswillbeimplementedinaconsistent,repeatablemanner.Identifydeviationsfromthedesigncodeofrecord.Response*MethodologyDocumentestablishesanapproachtoperformaStage3analysisinaconsistent,repeatablemanner.*Supplementstothecodesofrecord-Supplement1-ConsiderationofASRloads-Supplement2-Codeacceptancecriteria-Supplement3-Shear-frictioncapacityformemberssubjectedtonetcompression-Supplement4-Flexuralcrackedsectionproperties-Supplement5-Axialandshearcrackedsectionproperties*UFSARmarkupwillberevisedtoreflectthesesupplements 11RAI-D3Request-ExplainwithsufficienttechnicaldetailhowtheproposedmomentredistributionapproachmeetsspecificrequirementsofACI318-71.Response*TheMethodologyDocumentlimitstheuseofmomentredistributionforallstructurestobeinaccordancewithACI318-71Section8.6.*TheCEBevaluationisbeingrevisedinaccordancewiththeMethodologyDocument.-Eliminatetheuseofmomentredistribution.-Considercrackedsectionproperties.

12RAI-D4Request-Explainwithsufficienttechnicaldetailhowthe"simplifiedmomentredistribution"methodisapplied.Response*AsdiscussedinresponsetoRAI-D3momentredistributionwillbelimitedtoACI318-71section8.6.*TheCEBevaluationisbeingrevisedwithouttheuseofmomentredistributionmethods.AppendixLoftheCEBEvaluationwillbesuperseded.Thesamestructuralmodelandboundaryconditionswereusedinpreviousanalysis.

13RAI-D5(a)Request-ClarifywhatthethresholdfactorrepresentsinStage3analysesandhowthefactorwillbedeterminedforfutureanalyses.Response*ThresholdfactorisdesignmarginexpressedastheamountASRloadscanincreaseandstillmeetACIcriteria.-Thresholdfactorisanoutputoftheevaluation,notaninputtothemethodology.-Auniquethresholdfactoriscalculatedforeachbuildingbasedontheavailablemargin.-Usedtoestablishthresholdlimitsformonitoredparameters.-ThismarginisavailabletoaccountforpotentialfutureASRexpansionwithoutreducingthecodeinherentmarginofsafety.*Thresholdfactormayberevisedbasedonfurtheranalysis,byusingadditionalinspectionandmeasurementdata,and/orusingamorerefinedstructuralanalysismethodwithoutreducingthecodeinherentmarginofsafety.

14Request-Explainifthereisalimitimposedontheextentofanalysisthatcanbeusedtomodifythedemandsuponastructureandifthisimpactsthespecificationofthethresholdfactor.Response*Thresholdfactorisanoutputofanevaluation(seeRAI-D5(a)).*Thereisnolimitonre-evaluationprovidedevaluationsatisfiesACICodeassupplemented.-MomentredistributionislimitedperACICode.*Re-evaluationswoulduseadditionalinspectionandmeasurementdata,and/oruseamorerefinedstructuralanalysismethodinaccordancewiththeMethodologyDocument.*Structuralmodificationmayberequiredtoreestablishmargin.RAI-D5(b)15RAI-D6Request-Clarifywhetherthe100-40-40methodwillbeimplementedinequivalentstaticanalysesforASR-affectedstructures.Ifso,providethetechnicalbasisforusingthemethodinconjunctionwithequivalentstaticanalysis.Response*The100-40-40methodwillbedeletedfromtheproposedmethodology-TheCEBevaluationisbeingrevisedtousethesquare-root-of-the-sumof-the-squares(SRSS)methodinconjunctionwiththeequivalentstaticanalysismethodconsistentwiththeoriginaldesigncalculationapproach.*UFSARmarkupswillberevisedtoremovereferencesto100-40-40.

16RAI-D7(a)Request-Provideanexplanationofhowmultipleloadcomponents(e.g.,axialforceandmoment)arecombinedtoperformcodeinteractionchecks.Response*TheMethodologyDocumentonlyallowstheuseofSRSSmethodforcalculationofseismicdemands.-TheCEBevaluationisbeingrevisedwithouttheuseofthe100-40-40method.*Forconditionswithmultiplecomponents(e.g.,axialforceandmomentP-Minteraction),theMethodologyDocumentrequires-AllcomponentsarecalculatedbytheSRSSmethod.-TheSRSScalculated+/-Pand+/-MwillbeusedforP-Minteractionevaluation.

17RAI-D7(b)Request-ExplainwhythecombinationofEO,andHeinsomecasesislessthanEO,alone.IftheexplanationassumesaphaserelationshipbetweenEO,andHe,providethetechnicalbasisfortheassumedphaserelationship.Response*FortheCEBcalculation,theseismicinertiaforce,EO,andsoilpushingtheembeddedpartoftheCEB,He,aremodeledin-phase.*In-phasemodelingmaximizesbaseshearandoverturningmomentwhenthestaticequivalentmethodandtheSRSSresponsesareused.*Theout-of-planebendingresponseinCEBisinfluencedbythepresenceoflargepenetrations,andlocationofappliedloadsincludingdynamicsoilloads.Thedynamicsoilresponseandinertialresponsemaycounteracteachotheratlimitedsmalllocations.*Analysesconsiderseismicmotioninoppositedirections.Resultsateachlocationareenveloped,thereforethelocalizedareasarecovered.

18RAI-D8Request-Explain,withsufficienttechnicaldetail,howtheproposedmethodofevaluationforASR-affectedstructuresverifiesthatthestressesandstrainsintheconcreteandreinforcementremainwithinelasticlimitsbasedonrealisticbehaviorundernormaloperating(service)loadconditions,includingASRload.Response*CompliancewiththeACICode,assupplementedbytheMethodologyDocument,ensuresstructuresbehaveelastically,andtherebarandconcretestressesandstrainsremainwithinacceptablelimits.

19RAI-D8Response(continued)*Performedtwoparametricstudiestoexaminerebarstresses.-Scope1.EffectofincreasingASRexpansionformembersubjectedtoexternalload.2.ImpactofincreasingloadonASR-affectedmember.-PreliminaryresultsfordiscussionRebarstressesremaininelasticrangefornormaloperating(service)loads.*AssessedrebarstressesforSeabrookstructures.-ScopeStructuresevaluatedtodate-PreliminaryresultsfordiscussionStressesandstrainsintheSeabrookstructuresareshowntobewithinelasticlimitsundernormaloperatingloadconditions(unfactoredloads)whenASRloadsareconsidered.

20-800-600-400-2000200400-400-300-200-1000100200300400Axialforce(kip/ft)Moment(kip-ft/ft)P-MinteractionUltimatestrengthServicestressCaseACaseBCaseCCaseDCaseECaseFCaseGCaseHCaseICaseJCaseKCaseLP-MCombinationsCasesParametricStudy1-Stressintensionrebaroftypical2ftthickmembersubjectedtoP-MandincreasingASRstrainPreliminaryResults-verificationpending.

21ParametricStudy1-Stressintensionrebaroftypical2ftthickmembersubjectedtoP-MandincreasingASRstrainFactoredloadServiceload-1001020304050607000.511.522.5Rebar1stress(ksi)InternalASR(mm/m)CaseACaseBCaseCCaseDCaseECaseFInternalASRonlyfy=60ksi-1001020304050607000.511.522.5Rebar1stress(ksi)InternalASR(mm/m)CaseGCaseHCaseICaseJCaseKCaseLInternalASRonlyfy=60ksi*ThetensilestressintherebarincreasesafterASRexpansionissufficienttoclosestructuralcracksaroundthetensilerebar.*Forsectionswithalreadyhighlevelsofexternalload(factoredlevelloads),highlevelsofASRareneededtocauseadditionaltensilestressinrebar.PreliminaryResults-verificationpending.

22ParametricStudy2-Stressintensionrebaroftypical2ftthickASR-affectedmemberwithincreasingmoment*Self-strainingconcretecompressivestresseffectwillunloadbeforerebartensilestressincreases.Thisisbecausetheconcretesectionismuchstifferthanthesteelbasedonthereinforcementratio.*Stressesandstrainsinsteelrebararelessthantheelasticlimitsatserviceloadconditions,providedthatASRstrainislessthansteelyieldstrain(2mm/m).PreliminaryResults-verificationpending.-2002040600204060Rebar1stress(ksi)Moment(kip-ft/ft)0mm/m0.5mm/m1mm/m1.5mm/m2mm/m 23StressesinSeabrookStructureduetoServiceLoad*Thestressesforthestructuresthatarecompletedorbeingcompletedhavebeencalculatedforthefollowingtwoserviceloadconditions:-insitucondition:D+L+E+To+Sa-insituconditionplusoperatingbasisearthquakeandpotentialfutureASRexpansionuptothresholdlimit:D+L+E+To+Eo+He+FTHR*Sa*Fortheaboverealisticunfactoredserviceloadcombinations,stressesinrebararebelowyield,andconcretestrainsarelessthan0.001andarelessthanthe0.003ACICodemaximumusablestrainforconcretecompression 24Maximumsteelrebartensilestressandconcretecompressivestressforinsitucondition:D+L+E+To+SaStructureAnalysisStageASR(mm/m)ComponentMaximumtensilestressinrebar(ksi)Maximumcompressivestressinconcrete(ksi)MaximumcompressivestraininconcreteCRMAI30.99BaseMat27.8-0.28-0.00009RHR30.75Eastexteriorwall47.0-1.8-0.00058CSTE20.43Tankwall16.0-0.66-0.00018CEHMS10.72Eastwingwall31.3-0.78-0.00025CEVA10.31Baseslab32.8-0.88-0.00028CEB30.60WallbetweenMech.&Elec.Penetration24.6-2.19-0.00065WPC/PH20.24Northwall6.5-0.49-0.00016EMH10.25W13/W15walls7.3-0.03-0.00001PreliminaryResults-verificationpending.

25StructureAnalysisStageASR(mm/m)ComponentMaximumtensilestressinrebar(ksi)Maximumcompressivestressinconcrete(ksi)MaximumcompressivestraininconcreteCRMAI30.99x1.4BaseMat39.1-0.37-0.00012RHR30.75x1.2Eastexteriorwall56.5-2.1-0.00067CSTE20.43x1.6Tankwall26.7-1.11-0.00031CEHMS10.72x1.5Eastwingwall41.6-1.52-0.00049CEVA10.31x3.0Baseslab44.0-1.08-0.00035CEB30.60x1.3WallbetweenMech.&Elec.Penetration44.0-2.8-0.00091WPC/PH20.24x1.8Northwall23.2-0.85-0.00027EMH10.25x3.7W13/W15walls26.8-0.11-0.00004MaximumsteelrebartensilestressandconcretecompressivestressforinsituconditionplusoperatingbasisearthquakeandfutureASRexpansionuptothresholdlimit:D+L+E+To+Eo+He+FTHR*SaPreliminaryResults-verificationpending.

26Summary*TheMethodologyDocumentprovidestheapproachforperformingallthreestagesofanalysesdescribedintheLARcanbeimplementedinaconsistentandrepeatablemannerbyaknowledgeablestructuralengineer.*UseofmomentredistributionforstructureswillbeinaccordancewithACI318-71Section8.6.*The100-40-40methodwillnotbeconsideredforcalculatingseismicdemandsforanySeismicCategoryIstructuresatSeabrook.TheUFSARmarkupwillberevisedtousetheoriginalSRSSmethods.*CompliancewiththeACICode,assupplementedbytheMethodologyDocument,ensuresstructuresbehaveelastically,andtherebarandconcretestressesandstrainsremainwithinacceptablelimits.

27BuildingDeformationAnalyses(1of2)StructureSchedulePercentCompleteIncorporatedtoSMPCondensatewaterstoragetankComplete100%CompleteContainmentenclosurebuilding(revision)4Q201780%Complete**2/2018(Rev1)**ContainmentenclosureventilationareaComplete100%CompleteContainmentstructureComplete100%CompleteEquipmenthatchmissileshieldComplete100%CompleteControlroommake-upairintakeComplete100%CompleteElectricalcabletunnelsComplete100%CompletePre-actionvalvebuilding4Q201780%2/2018RHRequipmentvaultComplete100%CompleteContainmentinternalstructures4Q201790%2/2018Mainsteamandfeedwatereastpipechase4Q201770%2/2018HydrogenrecombinerstructureStage1Safety-relatedelectricalductbanksandmanholes1Q201880%4/2018Stages2and3Safety-relatedelectricalductbanksandmanholes1Q201840%4/2018Emergencyfeedwaterpumpbuilding1Q201850%4/2018Fuelstoragebuilding4Q201780%2/2018Structuresthatare/expectedtobeStage3 28BuildingDeformationAnalyses(2of2)StructureSchedulePercentCompleteIncorporatedtoSMPControlBuildingDieselGeneratorBuilding1Q201830%4/2018MechanicalPenetrationPersonnelhatcharea1Q201840%4/2018Mainsteamandfeedwaterwestpipechase4Q201790%2/2018Primaryauxiliarybuilding4Q201730%2/2018Servicewatercoolingtowerincl.switchgearrooms1Q20184/2018Servicewateraccess(inspection)vault1Q20184/2018Circulatingwaterpumphouse(belowel.21')Servicewaterpumphouse2Q20187/2018Piping(RCA)Tunnels2Q20187/2018Tankfarmarea2Q20187/2018Wasteprocessingbuilding2Q20187/2018Structuresthatare/expectedtobeStage3 29Questions?