RG1.106 马达操作阀门中的电动马达的热超载保护 1977

Revision1March1977U.S.NUCLEARREGULATORYCOMMISSIONREGULATORYGUIDEOFFICEOFSTANDARDSDEVELOPMENTREGULATORYGUIDE1.106THERMALOVERLOADPROTECTIONFORELECTRICMOTORSONMOTOR-OPERATEDVALVESA.INTRODUCTIONCriterion1,QualityStandardsandRecords,ofAppendixA,GeneralDesignCriteriaforNuclearPowerPlants,to10CFRPart50,LicensingofProductionandUtilizationFacilities,requires,inpart,thatcomponentsimportanttosafetybedesigned,fabricated,erected,andtestedtoqualitystandardscommensuratewiththeimportanceofthesafetyfunctionstobeperformed.Criterion4,EnvironmentalandMissileDesignBases,ofAppendixAto10CFRPart50requires,inpart,thatcomponentsimportanttosafetybedesignedtoaccommodatetheeffectsofandbecompatiblewiththeenvironmentalconditionsassociatedwithnormal,operation,maintenance,testing,andpostulatedaccidents,includingloss-of-coolantaccidents.Criterion13,InstrumentationandControl,ofAppendixAto10CFRPart50requiresthatinstrumentationbeprovidedtomonitorvariablesandsystemsovertheiranticipatedrangesfornormaloperationandforpostulatedaccidentconditionsandthatcontrolsbeprovidedtomaintainthesevariablesandsystemswithinprescribedoperatingranges.CriterionXI,TestControl,ofAppendixB,QualityAssuranceCriteriaforNuclearPowerPlantsandFuelReprocessingPlants,to10CFRPart50requires,inpart,thatatestprogrambeestablishedtoensurethatsystemsandcomponentsperformsatisfactorilyandthatthetestprogramincludeoperationaltestsduringnuclearpowerplantoperation.ThisregulatoryguidedescribesamethodacceptabletotheNRCstaffforcomplyingwiththeabovecriteriawithregardtotheapplicationofthermaloverloadprotectiondevicesthatareintegralwiththemotorstarterforelectricmotorsonmotor-operatedvalves.Thismethodwouldensurethatthethermaloverloadprotectiondeviceswillnotneedlesslypreventthemotorfromperformingitssafety-relatedfunction.TheAdvisoryCommitteeonReactor.,Safeguardshasbeenconsultedconcerningthisguideandhasconcurredintheregulatoryposition.B.DISCUSSIONMotor-operatedvalveswiththermaloverloadprotectiondevicesforthevalvemotorsareusedinsafetysystemsandintheirauxiliarysupportingsystems.Operatingexperiencehasshownthatindiscriminateapplicationofthermaloverloadprotectiondevicestothesevalvemotorscouldresultinneedlesshindrancetosuccessfulcompletionofsafetyfunctions.Thermaloverloadrelaysaredesignedprimarilytoprotectcontinuous-dutymotorswhiletheyarerunningratherthanduringstarting.Useoftheseoverloaddevicestoprotectintermittent-dutymotorsmaythereforeresultinundesiredactuationofthedevicesifthecumulativeeffectofheatingcausedbysuccessivestartsatshortintervalsisnottakenintoaccountindeterminingtheoverloadtripsetting.Itisgenerallyverydifficultforanythermallysensitivedevicetoapproximateadequatelythevaryingthermalcharacteristicsofanintermittent-dutymotoroveritsfullrangeofstartingandloadingconditions.ThisismainlycausedbytheWidevariationsinmotorheatingcurvesforvarioussizesanddesignsandalsobythedifficultyinobtainingmotorheatingdatatoanacceptableaccuracy.0Linesindicatesubstantivechangesfrompreviousissue.USNRCREGULATORYGUIDESCommentsshouldbesenttotheSecretaryoftheCommission.US.NuclearRegulatory,Commission.Washington.D.C.20555.Attention:Docketing&nWServceRegulatoryGuidesareissuedtodescribeandmakeavailabletothepublicmethodstranch.acceptabletotheNRCstaffofimplementingspecificpartsoftheCommission'sregulations,todelineatetechniquesusedbythestaffinevaluatingspecificproblemsTheguidesseissuedinthefollowingtenbroaddivisions:orpostulatedaccidents,ortoprovide&uidancetoapplicants.RegulatoryGuidesarenotsubstitutesforregulations,andcompliancewiththemisnotrequired.1.PowerReactors6.ProductsMethodsandsolutionsdifferentfromthosesetoutIntheguideswillbeaccept-2.ResearchandTestReactors7.Transportationableiftheyprovideabasisforthefindingsrequisitetotheissuanceorcontinuance4.EnvironmentalandcSiting9.AntitrustReviewof.permitorlicensebytheCommission.5.MaterialsandPlantProtection10.GeneralCommentsandsuwestionsforimprovementsIntheseguidesaeencouragedatallRequestsforsinglecopiesofIssuedguides(whichmaybereproduced)orforplacetimes,andguideswillberevised.asappropriate,toaccommodatecommeMtsandmentonanautomaticdistributionlistforsinglecopiesoffutureguidesinspecifictoreflectnewinformationorexperience.-ThisguidewasrevisedasamullofdivisionsshouldbemadeinwritingtotheUS.NuclearRegulatoryCommission.substantivecommentsreceivedfromthepublicandadditionalstaffreview.Washington,D.C.2055./Attention:Director.DivisionofDocumentControl.01Sincethetripfunctioninathermaloverloaddeviceisdependentontemperature,thedegreeofoverloadprotectionprovidedisaffectedbychangeinambienttemperatureatthemotororstarterlocation.Thisaspectbecomesmorecomplexinnuclearpowerplantapplicationswhere,insomecases,themotortobeprotectedisinsidethecontainmentandtheoverloadprotectiondevicesareoutsidethecontainment.Insuchasituation,thetemperaturedifferencebetweenthemotorandtheoverloaddevicecouldbeashighas2000Funderdesignbasisconditions.Thus,theselectionofanappropriatetripsetpointforsuchavalvemotorshouldtakeintoconsiderationoperationofthevalveundervarioustemperaturesforbothnormalandpostulatedaccidentconditions,in