RG1.204 核电厂闪电防护导则 2005

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-1137,datedFebruary2005)GUIDELINESFORLIGHTNINGPROTECTIONOFNUCLEARPOWERPLANTSA.INTRODUCTIONTitle10,Part50,oftheCodeofFederalRegulations(10CFRPart50),“DomesticLicensingofProductionandUtilizationFacilities,”delineatesthedesign-andqualification-relatedregulationsthattheU.S.NuclearRegulatoryCommission(NRC)hasestablishedforcommercialnuclearpowerplants.Inparticular,GeneralDesignCriterion2,“DesignBasesforProtectionAgainstNaturalPhenomena,”setforthinAppendixAto10CFRPart50,requires,inpart,thatstructures,systems,andcomponents(SSCs)thatareimportanttosafetyinnuclearpowerplantsmustbedesignedtowithstandnaturalphenomena.ThedesignbasesfortheseSSCsmustreflect(1)appropriateconsiderationofthemostsevereofthenaturalphenomenathathavebeenhistoricallyreportedforthesiteandsurroundingarea,withsufficientmarginforlimiteddata,quantity,andperiodoftimeinwhichthehistoricaldatahavebeenaccumulated;(2)appropriatecombinationsoftheeffectsofnormalandaccidentconditionswiththeeffectsofthenaturalphenomena;and(3)theimportanceofthesafetyfunctionstobeperformed.Fasttransientovervoltagesgeneratedbylightningdischargescancauseequipmentdamage,systemmalfunctions,orpowerinterruptionsatnuclearpowergeneratingplantsiftheplantsarenotadequatelyprotectedagainstsuchconditions.However,adequateequipmentandsystemdesigncangreatlyreduceoralleviatetheadverseconsequencesofabnormalvoltagedisturbances.ConfirmatoryresearchinsupportofthisobservationcanbefoundinNUREG/CR-6866,“TechnicalBasisforRegulatoryGuidanceonLightningProtectioninNuclearPowerPlants,”datedJuly2005.RG1.204,Page2ThisregulatoryguideoffersguidanceforNRClicenseesandapplicantstouseindevelopingandimplementingpracticesthattheNRCstafffindsacceptableforcomplyingwiththeagency’sregulatoryrequirements.Specifically,thisguidanceappliestothedesignandinstallationoflightningprotectionsystems(LPSs)toensurethatelectricaltransientsresultingfromlightningphenomenadonotrendersafety-relatedsystemsinoperableorcausespuriousoperationofsuchsystems.Thescopeoftheguidanceincludesprotectionof(1)thepowerplantandrelevantancillaryfacilities,withtheboundarybeginningattheserviceentranceofbuildings;(2)theplantswitchyard;(3)theelectricaldistributionsystem,safety-relatedinstrumentationandcontrol(I&C)systems,communications,andpersonnelwithinthepowerplant;and(4)otherimportantequipmentinremoteancillaryfacilitiesthatcouldimpactsafety.Thescopeincludessignallines,communicationlines,andpowerlines,aswellastestingandmaintenance.Thescopedoesnotcovertestinganddesignpracticesthatarespecificallyintendedtoprotectsafety-relatedI&Csystemsagainstthesecondaryeffectsoflightningdischarges[i.e.,low-levelpowersurgesandelectromagneticandradio-frequencyinterference(EMI/RFI)].ThesepracticesarecoveredinRegulatoryGuide1.180,“GuidelinesforEvaluatingElectromagneticandRadio-FrequencyInterferenceinSafety-RelatedInstrumentationandControlSystems.”RegulatoryGuide1.180,whichtheNRCissuedinJanuary2000andrevised