RG1.124 1级线性型支撑的在役极限和载荷混合 2007

TheU.S.NuclearRegulatoryCommission(NRC)issuesregulatoryguidestodescribeandmakeavailabletothepublicmethodsthattheNRCstaffconsidersacceptableforuseinimplementingspecificpartsoftheagency’sregulations,techniquesthatthestaffusesinevaluatingspecificproblemsorpostulatedaccidents,anddatathatthestaffneedinreviewingapplicationsforpermitsandlicenses.Regulatoryguidesarenotsubstitutesforregulations,andcompliancewiththemisnotrequired.MethodsandsolutionsthatdifferfromthosesetforthinregulatoryguideswillbedeemedacceptableiftheyprovideabasisforthefindingsrequiredfortheissuanceorcontinuanceofapermitorlicensebytheCommission.Thisguidewasissuedafterconsiderationofcommentsreceivedfromthepublic.TheNRCstaffencouragesandwelcomescommentsandsuggestionsinconnectionwithimprovementstopublishedregulatoryguides,aswellasitemsforinclusioninregulatoryguidesthatarecurrentlybeingdeveloped.TheNRCstaffwillreviseexistingguides,asappropriate,toaccommodatecommentsandtoreflectnewinformationorexperience.WrittencommentsmaybesubmittedtotheRulesandDirectivesBranch,OfficeofAdministration,U.S.NuclearRegulatoryCommission,Washington,DC20555-0001.Regulatoryguidesareissuedin10broaddivisions:1,PowerReactors;2,ResearchandTestReactors;3,FuelsandMaterialsFacilities;4,EnvironmentalandSiting;5,MaterialsandPlantProtection;6,Products;7,Transportation;8,OccupationalHealth;9,AntitrustandFinancialReview;and10,General.Requestsforsinglecopiesofdraftoractiveregulatoryguides(whichmaybereproduced)shouldbemadetotheU.S.NuclearRegulatoryCommission,Washington,DC20555,Attention:ReproductionandDistributionServicesSection,orbyfaxto(301)415-2289;[e-mail]ideandotherrecentlyissuedguidesareavailablethroughtheNRC’spublicWebsiteundertheRegulatoryGuidesdocumentcollectionoftheNRC’sElectronicReadingRoomat’sAgencywideDocumentsAccessandManagementSystem(ADAMS)at(DraftwasissuedasDG-1168,datedOctober2006)SERVICELIMITSANDLOADINGCOMBINATIONSFORCLASS1LINEAR-TYPESUPPORTSA.INTRODUCTIONGeneralDesignCriterion2,“DesignBasesforProtectionAgainstNaturalPhenomena,”ofAppendixA,“GeneralDesignCriteriaforNuclearPowerPlants,”toTitle10,Part50,“DomesticLicensingofProductionandUtilizationFacilities,”oftheCodeofFederalRegulations(10CFRPart50)requiresthatthedesignbasesforstructures,systems,andcomponentsimportanttosafetyreflectappropriatecombinationsoftheeffectsofnormalandaccidentconditionswiththeeffectsofnaturalphenomenasuchasearthquakes.Thefailureofmembersdesignedtosupportsafety-relatedcomponentsandpipingcouldjeopardizetheabilityofthesupportedcomponentorpipingtoperformitssafetyfunction.Thisguidedelineatesacceptablelevelsofservicelimitsandappropriatecombinationsofloadingsassociatedwithnormaloperation,postulatedaccidents,andspecifiedseismiceventsforthedesignofClass1linear-typecomponentandpipingsupports,asdefinedinSubsectionNFofSectionIIIoftheAmericanSocietyofMechanicalEngineers(ASME)BoilerandPressureVesselCode.Thisguideappliestolight-water-cooledreactors.Thisregulatoryguidecontainsinformationcollectionsthatarecoveredbytherequirementsof10CFRPart50andthattheOfficeofManagementandBudget(OMB)approvedunderOMBcontrolnumber3150-0011.TheNRCmayneitherconductnorsponsor,andapersonisnotrequiredtorespondto,aninformationcollectionrequestorrequirementunlesstherequestingdocumentdisplaysacurrentlyvalidOMBcontrolnumber.RegulatoryGuide1.84,“Design,Fabrication,andMaterialsCodeCaseAcceptability,ASMESectionIII,”provides1guidancefortheacceptabilityofASMECode,SectionIIIcodecasesandtheirrevisions,includingASMECodeCasesN-71andN-249.Codecasesidentifiedas“ConditionallyAcceptableSectionIIICodeCases”areacceptable,providedthattheyareusedwiththeidentifiedlimitationsormodifications.Rev.2ofRG1.124,Page2B.DISCUSSIONBackgroundLoad-bearingmembersclassifiedascomponentandpipingsupportsareessentialtothesafetyofnuclearpowerplantsbecausetheyholdcomponentsandpipinginplaceduringtheloadingsassociatedwithnormalandupsetplantconditionsunderthestressofspecifiedseismicevents,therebypermittingsystemcomponentsandpipingtofunctionproperly.Load-bearingmembersalsopreventexcessivemovementofcomponentsandpipingduringtheloadingsassociatedwithemergencyandfaultedplantconditionscombinedwiththespecifiedseismicevent,thushelpingtomitigatetheconsequencesofsystemdamage.Componentandpipingsupportsaredeformation-sensitivebecauselargedeformationscansignificantlychangethestressdistributioninthesupportsystemanditssupportedcomponentsandpiping.Toprovideuniformrequirementsforconstruction,componentandpipingsupportsshould,asaminimum,havethesameASMECodeclassificationasthatofthesupportedcomponentsandpiping.Thisguidedelineateslevelsofservicelimitsandloadingcombinations,inadditiontosupplementarycriteria,forASMEClass1linear-typecomponentandpipingsupports,asdefinedbyNF-1213ofSectionIII.Thisguidedoesnotaddress