RG1.071 可达性受限区的焊工资格 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-1167,datedOctober2006)WELDERQUALIFICATIONFORAREASOFLIMITEDACCESSIBILITYA.INTRODUCTIONThisguidedescribesamethodthatthestaffoftheU.S.NuclearRegulatoryCommission(NRC)considersacceptableforimplementingtheagency’srequirementsregardingthecontrolofweldingfornuclearcomponents,astheyrelatetolight-water-cooledandgas-cooledreactors.Inparticular,GeneralDesignCriterion1,“QualityStandardsandRecords,”asspecifiedinAppendixA,“GeneralDesignCriteriaforNuclearPowerPlants,”toTitle10,Part50,oftheCodeofFederalRegulations(10CFRPart50),“DomesticLicensingofProductionandUtilizationFacilities”(Ref.1)requiresthatstructures,systems,andcomponentsimportanttosafetyshallbedesigned,fabricated,erected,andtestedtoqualitystandardscommensuratewiththeimportanceofthesafetyfunctionstobeperformed.Toaugmentthatrequirement,AppendixB,“QualityAssuranceCriteriaforNuclearPowerPlantsandFuelReprocessingPlants,”to10CFRPart50requirestheestablishmentofmeasurestoensurethecontrolofmaterialsandspecialprocessessuchaswelding,aswellasproperwelderqualification.Moreover,10CFR50.55a,“CodesandStandards,”requires,inpart,thatcomponentsofthereactorcoolantpressureboundarymustbedesigned,fabricated,erected,andtestedinaccordancewiththestandardsinSectionIII,“NuclearPowerPlantComponents,”oftheBoilerandPressureVesselCode(Ref.2)promulgatedbytheAmericanSocietyofMechanicalEngineers(ASME),orequivalentqualitystandards.Rev.1ofRG1.71,Page2Thisregulatoryguidecontainsinformationcollectionsthatarecoveredbytherequirementsof10CFRPart50whichtheOfficeofManagementandBudget(OMB)approvedunderOMBcontrolnumber3150-0011.TheNRCmayneitherconductnorsponsor,andapersonisnotrequiredtorespondto,aninformationcollectionrequestorrequirementunlesstherequestingdocumentdisplaysacurrentlyvalidOMBcontrolnumber.B.DISCUSSIONSectionIII,“NuclearPowerPlantComponents,”oftheASMECode(Ref.2)specifiesstandardsforfabricatingClass1,2,and3components.PerformanceQualificationSectionIIIoftheASMECodeprovidesforadherencetoSectionIX,“WeldingQualifications,”which,inturn,callsforwelderqualificationforproductionwelding.Inparticular,reviewoftheperformancequalificationsinSectionIXindicatesthedesirabilityofsupplementaryrequirementstoprovideimprovedcontrolofweldertechniqueintheproductionweldingoflow-alloyandhigh-alloysteels.Specifically,theassuranceofsatisfactoryweldsinlocationswithrestricteddirectphysicalandvisualaccessibilitycanbesignificantlyincreasedbyqualifyingthewelderunderconditionssimulatingthespacelimitationsunderwhichtheactualweldsmustbemade.Experiencehasshownthatawelderwhoisqualifiedtoweldcomponentsundernormalfabricatingconditionsmaynotproduceacceptableweldsifaccessibilitytotheweldareaisrestricted.Limitedaccessibilitycanoccurwhencomponentpartsarejoinedorrepairedinthefinalassemblyorattheplantsiteifthelocationandotheradjacentcomponentsorstructurespreventthewelderfromassuminganadvantageouspositionduringtheweldingoperation.Limitedaccessibilityisparticul