ML17059A031
| ML17059A031 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 08/31/1993 |
| From: | NIAGARA MOHAWK POWER CORP. |
| To: | |
| Shared Package | |
| ML17059A032 | List: |
| References | |
| GL-92-01, GL-92-1, TAC-M83486, NUDOCS 9309140275 | |
| Download: ML17059A031 (74) | |
Text
NineMilePointUnit1DocketNo.50-220DPR-63TACNo.M83486GenericLetter92-01ElasticPlasticFractureMechanicsAssessmentforNineMilePointVnitI:ResponsetoNRCRequestforAdditionalInformation'August,1993,9309i40275930908PDRADOCK05000220PDR
TABLEOFCONTENTS
1.0INTRODUCTION
......2.0RESPONSESTOENCLOSURE1REQUESTSFORADDITIONALINFORMATION-SERVICELEVELSAANDB2.1InformationRequest1.-J-RModel2.2InformationRequest2.-MechanicsModel2.3InformationRequest3.-EffectofCladding~..............~.....5515163.0RESPONSESTOENCLOSURE2REQUESTSFORADDITIONALINFORMATION-SERVICELEVELSCANDD3.1InformationRequest1.-TemperatureDependencies3.2InformationRequest2.-95%ConfidenceProperties...............3.3InformationRequest3.-J-MaterialValues3.4InformationRequest4.-TransientDuration.....~....~~.........3.5InformationRequest5.-ThermalTransientParameters3.6InformationRequest6.-CladEquivalentStress3.7InformationRequest7.-StressIntensityFactorEquation...........'.3.8.InformationRequest8.-SampleCalculation18182122242631323
44.0REFERENCES
.........37Appendix-ExampleLevelCFlawStabilityCalculation........,...~.....~...38
1.0INTRODUCTION
NiagaraMohawkPowerCorporation(NMPC)submittedtheReference[MA92]reporttotheNRCbyletterdatedOctober16,1992.CommentsprovidedbytheNRCwereincorporatedintotheanalysisandarevisedreportwassubmittedonDecember17,1992[MA92b].TheNRClaterconcurredwithNMPCthattheA302BmaterialmodelisappropriateforanalysisoftheNineMilePointUnit1(NMP-1)beltlineplates,andareport[MA93]waspreparedwhichcontainsonlytheA302Bmaterialmodel(theA533Bmodelwasdeleted).The[MA93]reportwasnotsenttotheNRCbecausetheA302BmodelandresultsareidenticaltothosereportedinReference'[MA92b].Thesesubmittalscontainaplant-specificelastic-plasticfracturemechanicsassessmentforNMP-1underServiceLevelAandBloadings.AreportwhichcontainstheresultsforServiceLevelCandDloadings[MA93b]wassubmittedtotheNRConFebruary26,1993.TheanalysesdescribedinthesereportswereperformedinaccordancewiththedraftASMEAppendixX[ASME92],anddemonstratethatsufficientmarginsofsafetyagainstfractureexistthroughend-of-license(EOL).InaletterdatedJuly22,1993,theNRCindicatedthatapreliminaryreviewofthesereportshasbeencompletedandthatadditionalinformationisrequiredtocompletethereview.ThisreportwaspreparedinresponsetotheNRC'srequestforadditionalinformationandisfullyresponsivetoallinformationrequestsprovidedinEnclosures1and2oftheJuly22,1993letter.
0 2.0RESPONSESTOENCLOSURE1REQUESTSFORADDITIONALINFORMATION-SERVICELEVELSAANDB2.1InformationRequest1.-J-RModel"ThereportindicatesthattheJ-Rcurvefora6Tspecimentestedat180'1'isdrawntomeettheJaxisatJc=525in-lblin',thenthiscurveisshif)eddowntomaketheJpointcoincidewiththeestimatedJicpoint,leavingthedifferencebetweentheplateaulevelofJandJicconstantat175in-Iblin',independentofbothtemperatureandUSE.ProvidejustificationfortheassertedindependenceoftheJdifference(175in-Iblin)withrespecttotemperatureandUSEvalues.AlsojustifythattheproposedJ-RmodelshouldbreakdownwhenUSEvaluesreachzero.(AlthoughthisissuewasaddressedinatelephoneconferenceheldinJanuary1993,awrittenresponseisrequired)"RESPONSE:~BackcaadIncontrastwiththeJ-Rcurvedatatrendsforotherpressurevesselmaterials,Reference[H189]reportedanunprecedentedsizeeffectforA302Bsteel.AsshowninFigure2.1-1,thethickerthespecimen,thelowertheJ-RresponselevelaAerinitiation.Whilesimilardatatrendshavebeenobservedforsomepressurevesselmaterials,decreasesintheJ-RcurvesofthemagnitudereportedbyHiserhavenotbeenreportedearlier.Basedonchemicalandmicrostructuralconsiderations,itwasdeterminedthatthemodifiedA302B(A302M)NMP-1plateswouldexhibitductilefracturebehaviorsimilartothatpresentedinReference[HI89].Reference[HI89]reportedJ-Rdatafor0.5T,1T,2T,and4Tspecimens,butonlyone6Ttestwasperformed(180'F,T-Lorientation).ThemicromechanicalexplanationfortheJ-RcurvebehaviorshowninFigure2.1-1hasnotbeendefinitivelyestablished.Hiser[HI89]hasreportedbrittle-likesplits,orlaminatetearing,forallofthespecimenstested.Thesesplitsareorientedinthedirectionofcrackgrowthwithsmallamountsofmicrovoidcoalescenceintheregionbetweenthesplits.Thesize,relativenumber,anddistributionofthesplitsareapproximatelyconstantforvariousspecimensizes.Hiserconcludedthatthesplitsresultedfromseparationof,theinterfacebetweenthematerialmatrixandtheinclusions(sulfides,aluminides)and/orthesplittingofthemorebrittlealloyrichbondedstructure(possiblybainite).Theonlyapparentdifferenceinthefractureofsmallandlargespecimensisthetotalnumberofsplitsandnottherelativeproportion,Acomplete~micromechanicalexplanationisnotyetavailable.ReferenceMA92AnalsisSincetherearenotsufficientthick-specimendata(6Tto8T)availableatpresenttodefinitivelyestablishtherelationshipbetweenJ<<andtheJplateau(hJ),asafunctionoftoughnesslevel(inparticular,USElevel),theReference[MA92]analysiswasperformedassumingthatthedifferencebetweentheplateaulevelofJandJ<<isaconstantequalto175in-
Ib/in'overtherangeofUSElevelsfrom10it-lbsto100A-lbs).Atthetimetheanalysiswasperformed,itwasrecognizedthatthe175in-lb/indifferencemaychangesomewhatasthetoughnessofthesteelvaries.HowevertheUSElevelforthissteelis52ft-lbs(T-L),whichisroughlyinthemiddleoftherangeoverwhichtheJ-Rcurvescalingwasdone.Therefore,itwasjudgedthatthedifferencebetweentheactualmaterialbehavior,andthematerialmodelbasedontheassumptionofaconstantB,J=175in-lb/in',wouldbesmallandadequatelyrepresentedbyotherconservatisminthemodel.SincethereisnophysicalbasisuponwhichtovaryhJastheUSElevelischanged,thechoiceofaconstanthJobtainedfrom6Tdataisareasonablemodellingassumption.6JCharacterizationTheNRChasrequestedthatjustificationfortheconstantb,Jusedinthe[MA92]calculationsbeprovided.Unfortunately,asdiscussedabove,withoutextensiveadditionaltestingandanalysis,completejustificationcannotbeprovided.Inparticular,sincetheplateauforthe6TA302Btestissolowat52A-lbs,itispossiblethattheh,JvariationatlowerUSElevelsmaynotscale,inthesamemannerasotherRPVmaterials.Intheabsenceofadditionaldata,calculationshavebeenperformedusing0.5Tand1TdatatoassessthehJvariationatlowtoughness.Sinceitislikelythatthesedataareconservativeincomparisonwith6TA302Bdata,thecalculationsprovidedbelowshouldbeviewedasworstcaseimpactassessments.Inandefforttocharacterizetheh,Jvariationwithtoughness,0.5Tand1TdatafromReferences[MEA90]and[MEA83]wereanalyzed.Thephysicalcrackextension(ha,)fortheanalysesreportedinReference[MA92]isontheorderof0.1in.Therefore,6Jforthe0.5Tand1TdatawascalculatedbysubtractingJ<<fromJatha;-0.1in.(J).Itisimportanttonotethatthethinspecimensatintermediatetohightoughnesslevelsdonotexhibitaplateauatsmallh,aaswiththe6TA302Bdata.However,thesmallspecimendatacanbeusedtoobtainanestimateofthelLJvariationwithtoughness.Infact,atthepresenttime,thisistheonlymethodavailableforcharacterizingthehJvariation.ThesedataarepresentedinFigure2.1-2.TheReference[MEA83]J-RpowerlawformulationwasusedtomodelthedatashowninFigure2.1-2.Themodel,determinedfromleastsquaresregression,isgivenby:where,J=C(ha)'=J-Integral(in-lb/in')C=1000[-0.4876(USE/100)+7.5611(USE/100)'](in-lb/in')ha=crackextension(in)n=0.267(C/1000)'""Figures2.1-3and2.1-4illustratethefunctionalformofCandn.TheresultsobtainedusingthepowerlawmodelareshowninTable2.1-1andinFigure2.1-2.Themodelrepresentsthe0.5Tand1Tdatawell,andapproachesaphysicallymeaningfullimitatlowtoughness.Asexpected,
themodelshowsthataconstanthJ=175in-lb/in'sconservativeforUSElevelsaboveabout40ft-lb,butissomewhatnon-conservativeforUSElevelsbelow40ft-lb.InordertoassesstheimpactofadecreasinghJwithtoughness,thefollowingmaterialmodelwasanalyzed:USEft-ib10203040-100~EJinib/in/02082175TheabovedescribedJ-RmaterialmodelisthesameasthatdescribedinReference[MA92];exceptthatbelow40ft-ibtheb,Jvariedinaccordancewiththeabovelisteddata.TheresultsofthisanalysisareshowninTable2.1-2.Reviewofthesedatashowsthatevenifh,JweretodecreasedramaticallyatUSElevelsbelow40ft-lb,theminimumallowableUSEisbelowtheprojectedmaterialUSEatEOL.MaterialModelTemeratureDeendenceWithregardtothequestionoftemperaturedependenceoftheJ-Rcurves,the6TJ-Rtestat180'F[HI89]isexpectedtoconservativelyrepresentthematerialbehavioruptoreactoroperatingtemperature.AsshowninFigure2.1-5,the6Ttestwasperformedatatemperatureslightlyhigherthantheon-setoftheuppershelf.TheCharpydataindicatetemperatureindependencefromabout165'Fuptoreactoroperatingtemperature.NMPCPositionItisNMPC'spositionthattheresultsoftheAppendixXanalysisreportedinReference[MA92]areaccurateandconservative.Atpresent,therearenotsufficientdataavailabletocharacterizethevariationofh,Jwithtoughnessforthicksectioncomponents.Therefore,theuseofaconstant4J=175inlb/in'sreasonableandisexpectedtoyieldamaterialmodelwhichaccuratelyrepresentsthicksectionbehavior.~J-USEModelBehavioratLowTouhnessTheJ-RmodelfortheA302BmaterialreliesonthecorrelationofJ<<withUSEasshowninFigure4-12oftheDecember17,1992submittal.IfitwerepossibletoproduceamaterialwithUSE=0(i.e.,noenergyrequiredtodriveacrack),thenJ<<mustalsobezero(i.e.,'ocrackdrivingforcerequired).Therefore,thetheoreticallimitforaJ<<vs.USEcorrelationastoughnessdecreasesistheorigin.ThisdatatrendisclearlydemonstratedinFigure4-12.However,asapracticalconsideration,theUSEforferriticRPVsteelswouldnotbeexpectedtodropbelowthelowershelfenergylevel.Reference[MEA90]showsthatthelowershelfforA302Bsteelisintherangeof4-18ft-lbs.Therefore,asthematerialtoughnessdecreases,theJ,c-USEcorrelationisexpectedtodescribethematerialfracturebehaviorastheUSElevelapproachestheCharpylowershelfenergylevel.
A302BJ-RDATAFORVARIOUSSPECIMENTHICKNESSES'15001000XlICO05500CDO0k~~;~kaJ~~~~~~~+MID~~cI0.5TDATA<0.5TDATA00.5TDATA40.5TDATA*0.5TDATA*0.5TDATA01TDATA+1TDATAo2TDATAa2TDATA<4TDATA44TDATA~6TDATADeltaa(ln.)Figure2.1-1ComparisonofJ;RCurvesforA302BPlate(DataTakenfrom[HI89])
J-RCurveDeltaversusJicA302BandA533BMaterial30002500Ol4tOIQI20005500C)u1000cd500PowerLawModel100020003000Jtc(in-Ibs/in**2)T-L~L-T+A533A302A302Figure2.1-2h,JasaFunctionofJ,cfor0.5Tand1TSpecimens
HUCLERRVESSELSTEELS288C,1T~,28-25%SGFILLEDSYNOLSRREIRRRDIRTED~-lKUNENTS~i-HROOGHTN4gkgJ~wCS~~C/18887.5611%(Cv/188)+2".4878%(cv/188)I.BCv/IBB(ft-lb)2.BFigure2.1-3CorrelationofNormalizedCoefficientswithNormalizedCharpyUpperShelfEnergyValuesPvKA83]10
1.88NUCLERRVESSELSTEELS288oC~iTCT~2825~SGFILLEDSYMBOLSRREIRRRDIRTED.68ggSgWggSOhgh0glhn-8.2SC(CiBBB)82'62aa-gQMENTS>>-NROUGHT8.888812Cti888(4roaEq.3-i)28Figure2.1-4CorrelationofPowerLawExponent"n"withCoefficient"C"[MEA83]
188TEHPERRTURE('F)I88288388A302-8PLATE(V50)NewData6858previousData48382818188TEHPERRTURE('C)Figure2.1-5ComparisonoftheAverageCurvefitstotheNewandthePreviousCDatafortheA302-BPlate.TheNewDataIndicateHigherOverallToughness,withaHigherUpperShelfEnergyLevelandLowerTransitionTempeiatures.IHI89]12
Table2.1-1PowerLawModelforb,JasaFunctionofToughnessUSE253040506080100J(0.1)(in-lb/in')223321547807109117092360SmallSpecimenDataJic.(in-lb/in')199239319399479639798hJ(in-lb/in')248222840861210701562h,JUsedin[MA92](in-lb/in'17517517517517517517513 0
Table2.1-2EAectof4JVariationontheMinimumUpperShelfEnergyLevelforNMP-1PlateG-8-1PlateASMEServiceLevelMaterialModelHawGrowthof0.1in.CriterionJi~Jo.iHawStabilityCriterionMinimumUSE(Ft-lbs)4J=175in-ib/in'lawGrowthof0.1in.CriterionJi~o.iFlawStabilityCriterionMinimumUSE(Ft-Ibs)Variable4JG-8-1G-8-1G-8-1A8cBDA302BA302BA302B1310231020333136313014 0
2.2InformationRequest2.-MechanicsModelltTheieportcontainsnodescriptionofthefracturemechanicsanalysisprocedure,i.e.theequationsusedforcalculatingJ,>,T,>,andP~,.Onlythenameofacomputer-programismentioned.EitherconJirmthattheequationsusedareidenticaltothoseinAppendixXorlistalltheequationswhichdier."RESPONSE:AsmentionedinSection3.0ofReferenceIMA92],theprocedureandequationsspecifiedinAppendixX[ASME92]forServiceLevelsAandBareidenticaltothoseusedtocalculatetheappliedJ,theappliedtearingmodulus,andinternalpressureatflawinstability,undertheJ-Integral/TearingModulusProcedure.15 C
2.3InformationRequest3.-EffectofCladding"ProvideinforniationregardingtheeffectofcladdingtothecalculatedappliedJvalue."RESPONSE:~BackcuadReference[ASME92]doesnotexplicitlyrecommendnorrequirethatcladstresseffectsbeincludedintheServiceLevelAandBanalysis.DiscussionswithseveralmembersoftheASMEWorkingGrouponFlawEvaluation(WGFE)indicatedthattheeffectsofcladdinghavebeendiscussed,butthegroupdoesnotplantorecommendincorporationofcladstressanalysisproceduresintoAppendixX.ASMEarticleA-3000,"MethodforK,Determination",doesrequireconsiderationofresidualandappliedstressofallforms,includingclad-inducedstress,tobeincludedinstressintensityfactorformulation.Therefore,NMPCincludedcladinducedstresseffectsforServiceLevelCandDloadings,becausetheServiceLevelCandDanalysesrequirecalculationstobeperformedforshallowsurfaceflawswherecladinducedstresscanbesignificant.However,cladstresseffectswerenotincludedintheServiceLevelAandBanalysesbecause1/4Tflawsarepostulatedintheseanalysesandthecladinducedstresswereassumedtobenegligible.EstimatedCladInducedStressEffectInresponsetotheNRCinformationrequest,theefFectofcladdingontheappliedJforServiceLevelAandBloadingshasbeenestimated.Surfacetensilestressesresultfromdifferentialthermalcontractionfromthestressreliefheattreatmentat1150'F.Alinearelasticmodelwasformulatedtocalculatethestressresultingfromcooldownfrom1150'F,andthemodelpredictsthatthehoopstressesexceedyieldbeforethevesselIDtemperaturereaches100'F.Anelastic-plasticfiniteelementanalysisofthecooldownfrom1150'Ftoroomtemperature,followedbyre-heatingto528'F,withasubsequent100'F/hrcooldown,wasperformed.Theresultsofthefiniteelementanalysisconfirmedtheanalyticalmodelpredictionofa36ksihoopstressinthecladduetodifFerentialthermalcontractionwhenthecooldownofthevesselwasterminatedatavesselIDtemperatureof100'F.Thestressintensityatthe1/4Tflawduetothecladstress~~)wascalculatedandfoundtobe6.6ksiVin.Thestressintensitymodelincludestheeffectsofthebasemetalcompressivereactionforce.TheminimumallowableUSEwascalculatedbyaddingK~tothestressintensityfactorsdefinedinAppendixX.TheAppendixXcalculativeprocedureswerefollowedandtheevaluationcriteriaapplied.TheresultsofthesecalculationsareshowninTable2.3-1.ReviewofthesedatashowsthatifcladstresseffectswereincludedintheServiceLevelAandBanalysis,theminimumallowableUSEisbelowtheprojectedmaterialUSEatEOL.r16
Table2.3-1EffectofCladStressontheMinimumUpperShelfEnergyLevelforNMP-1PlateG-8-1PlateASMEServiceLevelMaterialModelMinimumUSE(Ft-Lbs)WithoutCladStressEffectMinimumUSE(Ft-Lbs)WithCladStressEffectG-8-1A&BA302BFlawGrowthof0.1in.CriterionJi~Jo.i13FlawStabilityCriterion23FlawGrowthof0.1in.CriterionJi~o.i26FlawStabilityCriterion3717
3.0RESPONSESTOENCLOSURE2REQUESTSFORADDITIONALINFORMATION-SERVICELEVELSCANDD3.1InformationRequest1.-TemperatureDependencies"ThereportindicatesinSection4.1thattemperaturedependentpropertieswereusedinthethermalandstressanalyses.Providethedetailsofthesetemperaturedependencies."RESPONSE:Table3.1-1showsthetemperaturedependentpropertiesreferredtoinSection4.1ofReference[MA93b].ThefiniteelementsoAwarePVELD3]useslinearinterpolationwithinthematerialpropertytables.Thevolumetricheatcapacity(c)isrelatedtospecificheat(C,)anddensity(p)by:c=pC,Theinstantaneouscoefficientofthermalexpansionisdefinedintermsoftheslopeofthethermalstrainversustemperaturecurve:dera=-dTTheinstantaneouscoefficientisdifferentfromtheaveragecoefficientwhichisperhapsmorecommonly'sed.Whiletheaveragecoefficientmusthaveanassociatedreferencetemperature(thetemperatureatwhichthermalstrainiszero),theinstantaneousvaluedoesnot.Table3.1-2showstheaveragecoefficientofthermalexpansionthatwasautomaticallygeneratedbythefiniteelementsofbvarefromtheinputinstantaneousvalues.Thevaluesbasedonareferencetemperatureof1150'Fwereusedincomputingtheinitialresidualstressstateduetoslowcoolingfromastress-freeconditionat1150'Fto528'F.Thevaluesbasedona'referencetemperatureof528'FwereusedforthetransientthermalanalysesassociatedwithLevelCandLevelDloadings.18
Table3.1-1TemperatureDependenceofMaterialPropertiesTemperatureConductivityVol.HeatCapacityElasticModulusPoisson'sRatioInst.Coef.Th.Exp.(T):(k):(G)(E):(v)-(a).OFBtu/in/sec/'FBtu/iq/'Flh/innondimensional1/oFStainlesssteelTk50.0.000182300.0.000212550.0.000242750.1000.1300.claddingc0.03120.03460.0371(type304)E28700000.27100000.25800000.24200000.22500000.20200000.0.260.280.310.320.300.280.000008160.000008940.000009600.000010030.000010560.00001141A302BhasemetalTkc50.300.550.750.1000.1300.0.0005340.02980.0005720.03410.0005530.037630000000.29000000.27700000.26200000.24500000.22200000.0.280.280.280.280.280.280.000006070.00000710=0.000008160.000008940.000010000.00001100NOTE:Dataforkandcattemperaturesabove550'Farenotprovidedsincethermaltransientanalyseswereperformedattemperaturesbelow550'F.19
Table3.1-2AverageCoefficientsofThermalExpansionforReferenceTemperaturesof1150'Fand528'FStainlesssteelcladding(type304)a,(1/oF)50.300.550.750.1000.1300.A302Bhasemetal1150oF9.64330E-069.96485E-061.02544E-051.04741E-051.07725E-051.11975E-05528oF8.87958E-069.24096E-069.57096E-069.79082E-061.00579E-051.04181E-056,(1/oF)50.300.550.750.1000.1300.1150~F8.33523E-068.85000E-069.35833E-069.76250E-061.02500E-051.07500E-05528DF7.06121E-067.58336E-068.11336E-068.50673E-069.01694E-069.59326E-0620
3.2InformationRequest2.-95%ConfidenceProperties"1'igure4-12inthereportdatedDecember17,1992,andinapreviousreportdatedOctober16,1992,indicatesthattheMean-2opropertiesandthe95%confidenceproperties(Mean'-1.645o)giv'ethesamelowerboundline.ClarifythisandconfirmthatMean-2apropertieshavebeenusedforLevels2,8,andCanalyses."RESPONSE:TheOctober16,1992,reportisbasedon95%lowerboundconfidencelimits.Inparticular,the95%lowerboundJ<<valuesshowninFigure4-12werecalculatedusing:Jic=3.1(USE),USE(75ft-lbsJ<<=-363.4+7.93295(USE),USE>75ft-lbswhere,J<<=in-ib/in'SE=ft-IbTheportionofthemodelbetweentheoriginand75ft-1bswasdeterminedbasedonconservative~~engineeringjudgement.Theportionofthemodelabove75ft-lbscomesfromtheregressionanalysisandrepresentsthe95%confidencelowerbound.InresponsetotheNRC'srequest,the95%confidencelowerboundwas.replacedbyatwosigmalowerboundconfidenceintervalandthismodelwasdescribedintheDecember17,1992,submittal.Thetwosigmalowerboundmodelisgivenby:Jic=31(USE)~USE(75ft-lbsJic=-363.4+7.915(USE),USE>75ft-lbsTheportionofthemodelabove75ft-lbscomesfromtheregressionanalysisandrepresentsthetwosigmalowerbound.Theportionofthemodelbelow75ft-lbsisbasedonengineeringjudgementandisidenticaltothemodelusedintheOctober16,1992report.ItisNMPC'spositionthatthemodelusedbelow75ft-lbsismoreconservativethanatwosigmalowerboundlevel.SincetheJ-g.curvemodelbelow75ft-ibsusedintheOctober16,1992,reportisthesameasthatusedintheDecember17,1992,report,andtheminimumallowableUSEisbelow75ft-Ib(calculationsyielded23ft-lbs),theminimumallowableUSEwhichwascalculateddidnotchangewhenthetwosigmamodelwasused.Insummary,mean-2opropertieshavebeenusedforServiceLevelA,B,andCanalyses.21
3.3InformationRequest3.-J-MaterialValuesIITheJmatenalvaluesat0.1inchlistedinTable5-3arelowerthanthecorrespondingvaluesinFigures5-1to5-4and5-7to5-10intheLevelsAdcBreportbyapproximately6lbs.Explainthisdifference."RESPONSE:AsdescribedinReference[MA93b],pointwiseexperimentaldata,scaledtoaccountforthetoughnesslevel,wereusedintheanalysis.TheUSE(3.0)codeusesamulti-linearrepresentationwithinterpolationwhenthepointwiseinputoptionisused.Asanexample,thematerialJp,datuminTable5-3ofReference[MA93b]at30ft-ibs(J=261in-lb/in')wasdeterminedbyinterpolatingthepointwiseJ-Rdata.ThematerialmodelinputforthiscaseisshowninTable3.3-1.ThedatainTable3.3-1showsthattheplateaubeginsat4a=0.112in.withJ=267.4in-Ib/in'.Thus,theapparentdiscrepancyisanartifactofthepointwisemodel.CarefulexaminationofFigures5-1to5-4and5-7to5-10oftheReferenceIMA92]reportshowsthattheinterpolatedJ-materialvaluesat0.1inchhave'beencorrectlycalculatedandtheJ-Rcurvesarecorrectlyplotted.22
Table3.3-1USE3.0OutputListingShowingJ-RCurvePointwiseInput02/15/199315'-NPIP-1PLATEG"8"1A302BMATERIALNODELANALYSISCURVE¹JIC=92.4k'44$g4444$)kff4$)k$)gg)kgb)kg)kgb)}'4$$$$)kgffffgggggg)gg)l(4444)kg$$$44$44444441.CorresoondinauooershelfenerovUSE=30(ft-Ibs)¹1¹2¹3:¹¹5:¹6:¹7:¹8:¹9:¹10¹11:¹12¹13:¹14¹15:¹16:¹17¹18:19:¹20:Deltaa0.0020.0040.0050.0060.0100.0170.0170'220.0230.0250.0300.0320.0360.0430.0480.0560.0680.0730.0830.098JDelta.a21.600¹21:0.112~33.400¹22:3.00055.30075.00095.000109;-400116.400136.400144.400154.400165.400183'00191.400201.400210.400218.400225.400240.400247.400260.400J267.400268.00023
3.4InformationRequest4.-TransientDuration"LevelsCandDtransientsmustbeanalyzedfromthebeginningofthetransienttothetimeatwhichthemetalatthetipoftheJlawbeinganalyzedreachesatemperatureequivalenttotheadjustedRT>>rplus50'F.Confirmthatthispracticehasbeenadoptedorproviderevisedanalyses."RESPONSE:ForserviceLevelsCandD,theARTNDTforplateG-307-4rangesbetween144'Fand163'Ffromthe1/4TpositiontotheIDsurfaceat18EFPY.Therefore,theARTNDrplus50'Fwouldrangefrom199'Fto210'F.Theblowdowntransientsareterminatedwhenthepressurereaches35psigtoaccountforthecontainmentpressurelevelatthattimeinthetransient.IntheReferencePdA93b]thermalstresscalculations,thesetransientswereextendedtolongertimes,conservativelyassuminga300'Fperhourcooldowntoa212'FvesselIDtemperature.Thus,theLevelCandDtransientswerenotanalyzedtoatemperatureequivalenttotheARTNDrplus50'Fattheflawtip.However,asdiscussedinReferenceIMA93b],thelimitingtransientsexperiencedpeakthermalandmechanicalloadspriortothepointwhenthetransientanalysiswasterminated.ThecooldownfromthefinaltransientconditionstoARTNTplus50'Fisacontrolledevolutionwhichisnotincludedinthetransientdefinitionandisproperlyconsideredasarecoveryaction.Thecooldownfrom212'Fwouldbeboundedbytheemergencycooldowneventandinmostcaseswouldbeboundedbythenormaloperationcooldownanalysis.ThestandardGEthermalcycletransientdefinitionusedforthedesignbasisemergencyandfaultedstressanalysisdoesnotincludeacooldowntoARTNDTplus50'F.ThestandardGEthermalcyclediagramisthebasisforthelimitingLevelC(emergency)andlimitingLevelD(faulted)thermaltransientusedfortheReferencePvtA93b]analyses.ThestandardLevelCandDtemperatureandpressuretransientaredefinedbasedonthedesignbasiseventandareterminatedwhentheeventisstabilized.ThecooldownfromthefinalstabilizedtransientconditiontotheARTNDTplus50'Fiscontrolledbyoperatoractionsandemergencyoperatingprocedureguidelines.Ingeneral,theoperatorguidelinesincludemaintainingthecooldownwithinthe100'Fperhournormalguideline.ForalltheLevelCtransientconditions,theoperatorcanbeassumedtohavetheabilitytocontroltherecoverycooldownratewithinthenormaloperatingguidelinesaAertheeventhasstabilized.ForthelimitingdesignbasisLevelDrecirculationlinebreakevent,theemergencyoperatingprocedureguidelinesincludeacontainmentfloodupwhichoccursovera6to12hourperiod.Containmentfloodupiscompletedusinglakewaterassumedtobeatthemaximumof81'Fandaminimumofapproximately35'F.Thelimitingassumptionwouldbethatthevesselwalltemperatureisrapidlycooledfrom212to100'F(ambientcontainmenttemperatureandpressureisapproximatedtoremaingreaterthan100'Fduetodecayheat).Thislimitingconditioniscloselyapproximatedbythenormalcooldownrateassumptions.24
AssumingtheNMP-1designbasisLOCAscenariowherethereactorisnotreflooded,theultimatecooldownfromsaturatedconditionsiscontrolledbythecontainmentaccidenttemperature.Theprimarycontainmentwetwellanddrywelltemperatureprofileresultsinthedrywellairspacetemperatureremaininggreaterthat175'Fforapproximately4hourswithasubsequentslowcooldownrate(muchlessthan100'Fperhourcooldown)linkedtothecontainmentheatremovalsystems.Insummary,theLevelCandDtransientswerenotanalyzedtothetimeatwhichthemetalatthetipoftheflawreachesatemperatureequivalenttotheadjustedRT~rplus50'F.However,thelimitingtransientsreachedpeakthermalandmechanicalloadspriortothepointwherethe.transientanalysiswasterminated.Therefore,theresultsreportedinReference[MA93b]arethemostconservativeresultsforanyoftheServiceLevelCandDtransients.25 0
3.5InformationRequest5.-ThermalTransientParameters"Supplyacompletelistofinputparametersandconditionsforthetransientthermalanalysis,includingspecificheat',thermalconductivity,,density,theresultingvalueofthermaldiffusivity,coefficientofthermalexpansion,elasticmodulusandPoisson'sratio(forbothcladdingandbasemetal);alsotherelationshipsneededtodeterminetheinsidesurfaceheattransfercoeJJicient."RESPONSE:Theinformationprovidedbelowdefinestheinputparametersandconditionsforthetransient,thermalanalysis.ThematerialpropertiesaregiveninTables3.5-1and3.5-2.Specificheats(C,)anddensities(p)werenotinputtothethermalanalysis.Volumetricheatcapacity(c),theproductofthesetwoparameters,wasinputinstead.Thermaldiffusivity(x)wasalsonotadirectinputtotheanalyses.However,itwascomputedfromtheconductivity(k)andheatcapacity(c)propertiesasfollows:x=k/cTable3.5-3summarizesthethermaldiffusivitiesresultingfromtheconductivitiesandheatcapacitieslistedinTable3.5-1.ThetimedependentinternalpressureandfluidtemperatureboundaryconditionsfortheLevelCandDloadingsaregiveninTables3-7(LevelC)and3-8(LevelD)ofthereport[MA93b].Theoutersurfaceofthevesselisassumedtobeinsulated.Thetimedependentheattransfercoefficientattheinnervesselsurfaceisalsogiveninthesetables.Thefiniteelementsofbvarelinearlyinterpolates(intime)betweentheinputvaluesofinternalpressureandfluidtemperaturethatarespecifiedbyTables3-7and3-8ofReference[MA93b].Theheattransfercoefficients(h),however,arenotlinearlyinterpolated.Theheattransfercoefficientsarechangedinthemodelinastepwisemanner.Forexample,inTable3-7[MA93b],hisheldat10,000untilatimeof380seconds;thenhischangedinstantaneouslytothenewvalueof164.Sincehneverincreasesduringthecriticaltimesofthesetransients,thisprocedureresultsinlargerhvaluesbeingusedfurtherintothecoolingtransient.Thisresultsinlargerthermalgradientsbeingcalculatedandthusconservativethermalstresspredictions.TheheattransfercoefficientsofTables3-7and3-8aregiveninunitsofBTU/hr/ft'/'F.TheanalysisusedunitsofBTU/sec/in'/'F.Table3.5-4providesthehvaluesofTables3-7and3-8[MA93b]intheunitsoftheanalysis.26 0
Table3.5-1TemperatureDependenceofMaterialPropertiesTemperatureConductivityVol.HeatCapacityElasticNoduluspoisson'sRatioInst.Coef.Th.Exp.(T):(k):(c):(E):(v).(a)oFBtu/in/sec/'FBtu/ip/Flb/innondimensional1/0F50.300.550.750.1000;1300.0.0001820.0002120.0002420.03120.03460.037128700000.27100000.25800000.24200000.22500000.20200000.A302BbasemetalTkStainlesssteelcladding(type304)TkcEV0.260.280.310.320.300.280.000008160.000008940.000009600.000010030.000010560.0000114150.300.550.750.1000.1300.0.0005340.0005720.0005530.02980.03410.037630000000.29000000.27700000.26200000.24500000.22200000.0.280.280.280.280.280.280.000006070.000007100.000008160.000008940.000010000.00001100Dataforkandcattemperaturesabove550'Farenotprovidedsincethermaltransientanalyseswereperformedattemperaturesbelow550'F.27
Table3.5-2AverageCoefficientsofThermalExpansionforReferenceTemperaturesof1150'Fand528'FStainlesssteelcladding(type304)0,(1/F)aveA302Bbasemetal50.300.550.750.1000.1300.11500F9.64330E-069.96485E-061.02544E-051.04741E-OS1.07725E-051.11975E-OSS28'F8.87958E-069.24096E-OG9.57096E-OG9.79082E-OG1.00579E-051.04181E-050,(1/F)50.300.550.750.1000.1300.11500F8.33523E-068.85000E-069.3S833E-069.76250E-OG1.02500E-051.07500E-05528oF7.06121E-067.58336E-OG8.11336E-068.50673E-069.01694E-069.59326E-OG
Table3.5-3ThermalDiffusivityDiffusivity(K):in/secStainlesssteelcladding(type304)TK=50.5.83E-03300.6.13E-03550.6.52E-03A302BbasemetalTK50.1.79E-02300.1.68E-02550.1.47E-0229
Table3.5-4HeatTransferCoefficientConversionBTU/hr!ft/'FBTU/sec'/inl'F69,18810,0005001641.33E-011.93E-029.65E-043.16E-0430 0
3.6InformationRequest6.-CladEquivalentStress"SupplythedetailedcalculationprocedurefordeterminingthecladequivalentstressvalueslistedinTable5-1."The"ExtrapolatedSurfaceStress"columninTable5-1ofReferenceIMA93b]isthestressatthepressurevesselIDsurfaceobtainedbyfittingthebasemetalfiniteelementcalculatedstressdistributiontothefollowingequation,a=Ao+A,X+A2X'A,X'here,A;=regressionconstantsX=distancethroughthewallandextrapolatingtotheIDsurface.The"CladStressMinusExtrapolatedSurfaceStress"columnisthedifferencebetweenthediscontinuouscladstressduetocooldownfromreactoroperatingtemperatureduringthetransientandtheextrapolatedbasemetalstressatthesurface.The"ResidualStress"columnisthetensilestressinthecladduetocooldownfrom1150'Ftoreactoroperatingtemperatureduringfinalstressrelief.The"CladTotalStress"columnisthesumofthe"CladStressMinusExtrapolatedSurfaceStress"dataandtheclad"ResidualStress"data.The"CrackSurfacePressure"columnisthestressonthecrackfacesduetocoolantpressure.The"CladEquivalentLineStress"columnwasobtainedbymultiplyingthe"CladTotalStress"bythecladthickness(5/32in.)toobtaintheequivalentlinestressforthestressintensitymodel,andaddingthe"CrackSurfacePressure"timesthemaximumanticipatedflawdepth(1.0in).Itisrecognizedthatthe"CrackSurfacePressure"maybeaddedtothebasemetalfiniteelementcalculatedstressdistributionandthenfitasdescribedearlier.However,theabovedescribedprocedureisconservativeandcomputationallysimpler.31 00 3.7InformationRequest7.-StressIntensityFactorEquation"Providethederivationorthereference(indicatingthepagenumber)ofEquation(5-3)."RESPONSE:Equation5-3ofReference[MA93b]canbefoundinthefollowingreferenceTheStressAnalsisofCracksHandbook,Tada,H.,Paris,P.,Irwin,G.,DelResearchCorporation,June,1973,page2.27AcopyoftheTadamodelisshowninFigure3.7-1.32
-2.27-F(~cQ~)3.52('l-/~)<.3o-5.28+~(I-N)s/-"(I-4)'2<-(Fa)*PCdt7IIIIZIOl~oOUi+JII02II0./0.6C/g0.8Method:EstimatedbyInterpolationAccuracy:F(c/a,a/b)-foraula$sexpectedtohave2Xaccuracyforanyvaluesofc/aanda/b
Reference:
Tada1974Figure3,7-1EquivalentLineLoadStressIntensityFactorEquation.33 C
3.8InformationRequest8.-SampleCalculation"Provideloadsandvaluesofdafortheresultslabelledunder"FlawStabilityCriterion"inTables5-3and5-4.Supplydetailsforonecalculation."RESPONSE:TheappliedstressesforthelimitingLevelCandDtransientsareprovidedinReference[MA93b].TheappliedJandhavaluesforthelimitingpostulatedfiawdepthundertheASMEAppendixXflawstabilitycriterionforLevelCloadingconditionsaregiveninTable3.8-1.SimilardataforLevelDloadingconditionsaregiveninTable3.8-2.Theresultsshownareforthelargesth,awhichcorrespondstothedeepestpostulatedinitialflawanalyzed.IterativecalculationswereperformedwhichallowthecracktoextendtoitsequilibriumlengthforcaseswheretheinitialJisgreaterthanJ<<.Aspectrumofinitialflaws,upto1/10ofthebasemetalwallthickness,wereassumed.Thesmallestpostulatedflawis0.05in.andtheinitialflawsizeswereincrementedby0.05in.uptoamaximuminitialflawdepthof0.75in.AsshowninTables3.8-1and3.8-2,forUSElevelsabove20Mbs,theflawgrowthislessth'an0.08in.ThereforetheJ-Rcurveplateauisnotreachedandstabletearingoccursuntiltheequilibriumflawdepthisreached.AsampleflawstabilitycalculationfortheLevelCloadingisprovidedinAttachment1.34
Table3.8-1AppliedLoadsandCrackExtensionforVariousUSELevelsAnalyzedUndertheASMEAppendixXFlawStabilityCriterionforLevelCLoadingConditionsandanAxialFlawOrientation'SELevel102030405060708090100FinalAppliedJ'in-ib/in~182.2181.5180.9180.7180.4179.8179.8.179.8179.8179.8h,aPhysical~in.0.07930.05080.03240.02460.01800.00.00.00.00.0AppliedT0.0960.1070.1140.1170.1200.1270.1270.1270.1270.127CriterionSatisfiedyesyesyesyesyesyes,J<Jrcyes,J<Jrcyes,J<J<<yes,J<J<<yes,J<J<<E'esultsshownarefor'thelargesth,awhichoccursforthedeepestpostulatedbasemetalflaw(a.=0.75in)'hefinalappliedJisiterativelycalculatedandrepresentstheappliedJaAerthecrackreachesitsequilibriumlength35 I'
Table3.8-2AppliedLoadsandCrackExtensionforVariousUSELevelsAnalyzedUndertheASMEAppendixXFlawStabilityCriterionforLevelDLoadingConditionsandanAxialFlawOrientation'SELevel10FinalAppliedJ'in-ib/in~haPhysical~in.AppliedTCriterionSatisfiedno20299.50.07300.129yes30405060708090.100297.6296.4296.4296.4296.4296.4296.4296.40.02550.00.00.00.00.00.00.00.1580.1740.1740.1740.1740.1740.1740.174yesyes,JCircyes,J'Jrcyes,J<Jrcyes,J<Jrcyes,JNrcyes,J<Jrcyes,J<J<<'esultsshownareforthelargesthawhichoccursforthedeepestpostulatedbasemetalflaw(a.=0.75in)'hefinalappliedJisiterativelycalculatedandrepresentstheappliedJaAerthecrackreachesitsequilibriumlength'6 0
4.0REFERENCES
[ASME92]ASMEDraftCodeCaseN-XXX,"AssessmentofReactorVesselswithLowUpperShelfCharpyEnergyLevels",Revision11,May27,1992.[HI89][MA92]Hiser,A.L.,Terrell,J.B.,"SizeEffectsonJ-RCurvesforA302BPlate",NUI&G/CR-5265,January,1989.ENMPCLetterfromC.D.TerrytoNRC,datedOctober16,1992,"Elastic-PlasticFractureMechanicsAssessmentofNineMilePointUnit1BeltlinePlatesforServiceLevelAandBLoadings".[MA92b]NMPCLetterfromC.D.TerrytoNRC,datedDecember17,1992,"Elastic-PlasticFractureMechanicsAssessmentofNineMilePointUnit1BeltlinePlatesforServiceLevelAandBLoadings".[MA93]Manahari,M.P.Sr.,"Elastic-PlasticFractureMechanicsAssessmentofNineMilePointUnit1BeltlinePlatesforServiceLevelAandBLoadings",FinalreportpreparedforNMPC,MPM-USE-293215,February,1993.[MA93b]NMPCLetterfromC.D.TerrytoNRC,datedFebruaiy26,1993"Elastic-PlasticFractureMechanicsAssessmentofNineMilePointUnit1BeltlinePlatesforServiceLevelCandDLoadings".[MEA83]MaterialsEngineeringAssociates,Inc.,Lanham,MD(Hiser,A.L.,andFishman,D.B.),"J-RCurveDataBaseAnalysisofIrradiatedReactorPressureVesselSteels",FinalreportpreparedforEPIU,December,1983.[MEA90]MaterialsEngineeringAssociates,Inc.,Lanham,MD,"InfluenceofFluenceRateonRadiation-InducedMechanicalPropertyChangesinReactorPressureVesselSteelsFinalReportonExploratoiyExperiments",preparedforNRC,NUIT/CR-5493,March,1990.[WELD3]"WELD3ComputerCodeVerification",MPMResearch&Consulting,CalculationNo.MPM-NMPC-99205,Rev.0,January21,1993.37 0
Appendix-ExampleLevelCFlawStabilityCalculation38