RG1.076 设计基准龙卷风和龙卷风飞射物 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-1143,datedJanuary2006)DESIGN-BASISTORNADOANDTORNADOMISSILESFORNUCLEARPOWERPLANTSA.INTRODUCTIONThisregulatoryguideprovideslicenseesandapplicantswithnewguidancethatthestaffoftheU.S.NuclearRegulatoryCommission(NRC)considersacceptableforuseinselectingthedesign-basistornadoanddesign-basistornado-generatedmissilesthatanuclearpowerplantshouldbedesignedtowithstandtopreventunduerisktothehealthandsafetyofthepublic.ThisguidanceappliestothecontiguousUnitedStates,whichisdividedintothreeregions;thisdocumentprovidesseparateguidanceforeachregion.Thisguidedoesnotaddressthedeterminationofthedesign-basistornadoandtornadomissilesforsiteslocatedinAlaska,Hawaii,orPuertoRico;theNRCwillevaluatesuchdeterminationsonacase-by-casebasis.Thisguidealsodoesnotidentifythespecificstructures,systems,andcomponentsthatshouldbedesignedtowithstandtheeffectsofthedesign-basistornadoorshouldbeprotectedfromtornado-generatedmissilesandremainfunctional.Thisguidealsodoesnotaddressextremewinds,suchashurricanes,orthemissilesattributedtosuchwinds.TornadowindspeedsmaynotboundhurricanewindspeedsforcertainportionsoftheAtlanticandGulfcoasts,atthewindspeedfrequenciesofoccurrenceconsideredinthisguide.TheNRCwilladdresstheseextremeconditionsonacase-by-casebasis.Thisguidealsodoesnotaddressotherexternallygeneratedhazardssuchasaviationcrashes,nearbyaccidentalexplosionsresultinginblastover-pressurelevelsandexplosion-bornedebrisandmissiles,andturbinemissiles.Rev.1ofRG1.76,Page2GeneralDesignCriterion(GDC)2,“DesignBasesforProtectionAgainstNaturalPhenomena,”ofAppendixA,“GeneralDesignCriteriaforNuclearPowerPlants,”toTitle10,Part50,oftheCodeofFederalRegulations(10CFRPart50),“DomesticLicensingofProductionandUtilizationFacilities”(Ref.1),requiresthatstructures,systems,andcomponentsthatareimportanttosafetyshallbedesignedtowithstandtheeffectsofnaturalphenomena,suchastornadoes,withoutlossofcapabilitytoperformtheirsafetyfunctions.GDC2alsorequiresthatthedesignbasesforthesestructures,systems,andcomponentsshallreflect(1)appropriateconsiderationofthemostsevereofthenaturalphenomenathathavebeenhistoricallyreportedforthesiteandsurroundingarea,withsufficientmarginforthelimitedaccuracy,quantity,andperiodoftimeinwhichthehistoricaldatahavebeenaccumulated,(2)appropriatecombinationsoftheeffectsofnormalandaccidentconditionswiththeeffectsofthenaturalphenomena,and(3)theimportanceofthesafetyfunctionstobeperformed.GDC4,“EnvironmentalandDynamicEffectsDesignBases,”ofAppendixAto10CFRPart50requires,inpart,thatstructures,systems,andcomponentsthatareimportanttosafetyshallbeadequatelyprotectedagainsttheeffectsofmissilesresultingfromeventsandconditionsoutsidetheplant.ForstationarypowerreactorsiteapplicationssubmittedbeforeJanuary10,1997,paragraph100.10(c)(2)of10CFRPart100,“ReactorSiteCriteria”(Ref.2),statesthatmeteorologicalconditionsatthesiteandinthesurroundingareashouldbeconsideredindeterminingtheacceptabilityofasiteforapo