RG1.027 最终热阱 1976

U.S.NUCLEARREGULATORYCOMMISSIONREGULATORYGUIDEOFFICEOFSTANDARDSDEVELOPMENTREGULATORYGUIDE1.27Revision2January1976ULTIMATEHEATSINKFORNUCLEARPOWERPLANTSA.INTRODUCTIONthesink.Thesinkperformsprincipalsafetyfunctions:(1)dissipationofheatafterreactorGeneralDesignCriterion44,CoolingWater,ofshutdownand(2)dissioidua1heatafteranAppendixA,GeneralDesignCriteria,to10CFRPartaccident.Foraseerunit,thesink50,LicensingofProductionandUtilizationFacilities,shouldbecapablesufficientcoolingwaterrequires,inpart,thatsuitableredundancyinfeaturesbetoaccomplishfunctions.providedforthecoolingwatersystemtoensurethatitsInconsidule-unitstation,itisrecognizedsafetyfunctioncanbeaccomplished.GeneralDesignthatthhsnuclearreactorunitincludesCriterion2,DesignBasesforProtectionAgainstsufficieýyepththatitishighlyunlikelythatNaturalPhenomena,requires,inpart,thatstructures,mthrsystems,andcomponentsimportanttosafetybemreactorunitwillbeinanaccidentanyparticulartime.Onthisbasis,thedesignedtowithstandtheeffectsofnaturalphenomenattii4tsinkcomplexservingmultipleunitsshouldwithoutlossofcapabilitytoperformtheirecaleofprovidingsufficientcoolingwatertofunctions.ThisguidedescribesabasisaccplemeptaleitsimultaneoussafeshutdownandcooldownofallNRCstaffthatmaybeusedtoimplementwpitsitservesandtomaintaintheminasafeshutdownDesignCriteria44and2withregardtoaondition.Also,intheeventofanaccidentinoneunit,utfeatureofthecoolingwatersystem,htoyofthesinkshouldbeabletodissipatetheheatforthatultimateheatsink.Thisguideappliestoetypaccidentsafely,topermittheconcurrentsafeshutdownnuclearpowerplantsthatusewat~meandcooldownoftheremainingunits,andtomaintainallultimateheatsink.Airheatexcheoro6eat-oftheminasafeshutdowncondition.dissipationmethodsusedasultimheatkswillbediscussedinfuturerevisionsorappen~al2ThecapacityofthesinkshouldbesufficienttoprovidecoolingbothfortheperiodoftimeneededtoB.CUSSIONTheultimatehS'einaftersink)forthecoolingwateatcomplexofwatersources,includingsatingstructures(e.g.,apondwithrwithitsdam),andthecanalsorconesourceswith,butnotincluding,watersystemintakestructuresforanuclearpowerThesinkconstitutesthesourceofserviceorhousetersupplynecessarytosafelyoperate,shutdown,andcooldownaplant.Thissafety-relatedwatersupplymaybesharedbynonsafetysystems(e.g.,circulatingwatersupply).Ifcoolingtowersorportionsthereofarerequiredtoaccomplishthesinksafetyfunctions,theyshouldsatisfythesamerequirementsasaT-.e.-....cantis,.hann,'rqfromRevision1.March1974.evaluatethesituationandfortheperiodoftimeneededtotakecorrectiveaction.Aperiodof30daysisconsideredtobeadequateforthesepurposes.Inaddition,proceduresshouldbeavailableforensuringthecontinuedcapabilityofthesinkbeyond30days.Sufficientconservatismshouldbeprovidedtoensurethata30-day'supplyofwaterisavailableandthatthedesignbasistemperaturesofsafety-relatedequipmentarenotexceeded.Forheatsinkswherethesupplymaybelimitedand/orthetemperatureofplantintakewaterfromthesinkmaybecomecritical(e.g.,ponds,lakes,coolingtowers,orothersinkswhererecirculationbetweenplantcoolingwaterdischargeandintakecanoccur),transientanalysesofsupplyand/ortemperatureshouldbeperformed.Acapacityoflessthan30daysmaybeacceptableifitcanbedemonstratedthatUSNRCREGULATORYGUIDESCommentsshouldbesenttotheSecretaryoftheCommission.U.S.NuclearRegulatoryCommission.Washington.D.C.20556.Attention:DocketingandRegulatoryGuidesareissuedtodescribeandmakeavailabletothepublicServiceSection.methodsacceptabletotheNRCstaffofimplementingspecificparisoftheCommission'sregulations,todelineatetechniquesusedbythestaffinevalu-Theguidesareissuedinthefollowingtenbroaddivisions:stingspecificproblemsorpostulatedaccidents,ortoprovideguidancetoapplicants.RegulatoryGuidesarenotsubstitutesforregulations,andcompliance1.PowerReactors6.Productswiththemisnotrequired.Methodsandsolutionsdifferentfromthosesetoutin2.ResearchandTestReactors7.Transportationtheguideswillbeacceptableiftheyprovideabasisforthefindingsrequisiteto3.FuelsandMaterialsFacilities8.OccupationalHealththeissuanceorcontinuanceofapermitorlicensebytheCommission.4.EnvironmentalandSiting9.AntitrustReviewCommentsandsuggestionsforimprovementsintheseguidesareencouraged5.MaterialsandPlantProtection10GeneraltaelItimes,andguideswillberevised,asappropriate,toaccommodatecommentsandtoreflectnewinformationorexperience.However,commentsonCopiesofpublishedguidesmaybeobtainedbywrittenrequest,indicatingthethisguide,ifreceivedwithinabouttwomonthsafteritsissuance,willbepardivisionsdesiredtotheU.S.NuclearRegulatoryCommission.Washington,D.C.ticularlyusefulinevaluatingtheneedforanearlyrevision20%65.Attention:Director.OfficeofStandardsDevelopment.replenishmentcanbeeffectedtoensurethecontinuouscapabilityofthesinktoperformitssafetyfunctions,takingintoaccounttheavailabilityofreplenishmentequipmentandlimitationsthatmaybeimposedonfreedomofmovementfollowinganaccident.Themeteorologicalconditionsconsideredinthedesignofthesinkshouldbeselectedwithrespecttothecontrollingparametersandcriticaltimeperiodsuniquetothespecific-designofthesink.Forexample,consideradrycoolingtowerasthesink.Thecontrol