RG1.145 潜在事故后果评价的大气弥散模型 1982

U.S.NUCLEARREGULATORYCOMMISSIONRevision1November1982REGULATORYGUIDEOFFICEOFNUCLEARREGULATORYRESEARCH(ReissuedFebruary1983tocorrectpage1.145-7)REGULATORYGUIDE1.145ATMOSPHERICDISPERSIONMODELSFORPOTENTIALACCIDENTCONSEQUENCEASSESSMENTSATNUCLEARPOWERPLANTSA.INTRODUCTIONSection100.10of10CFRPart100,ReactorSiteCriteria,statesthatmeteorologicalconditionsatthesiteandsurroundingareashouldbeconsideredindeterminingtheacceptabilityofasiteforapowerreactor.Section50.34of10CFRPart50,DomesticLicensingofProduc-tionandUtilizationFacilities,requiresthateachapplicantforaconstructionpermitoroperatinglicenseprovideananalysisandevaluationofthedesignandperformanceofstructures,systems,andcomponentsofthefacilitywiththeobjectiveofassessingtherisktopublichealthandsafetyresultingfromtheoperationofthefacility.Section50.34of10CFRPart50alsostatesthatspecialattentionshouldbedirectedtothesiteevaluationfactorsidentifiedin10CFRPart100intheassessmentofthesite.Theregulatorypositionspresentedinthisguiderepre-sentasubstantialchangefromprocedurespreviouslyusedtodeterminerelativeconcentrationsforassessingthepotentialoffsiteradiologicalconsequencesforarangeofpostulatedaccidentalreleasesofradioactivematerialtotheatmosphere.Theseproceduresnowincludeconsiderationofplumemeander,directionaldependenceofdispersionconditions,andwindfrequenciesforvariouslocationsaroundactualexclusionareaandlowpopulationzone(LPZ)boundaries3Thedirection-dependentapproachprovidesanimprovedbasisforrelatingthePart100-relatedreviewofaproposedreactortospecificsiteconsiderations.Accordingly,thisguideprovidesanacceptablemethodologyfordeter-miningsite-specificrelativeconcentrations(X/Q)andshouldbeusedindeterminingxJQvaluesfortheevalua-tionsdiscussedinRegulatoryGuide1.3,AssumptionsUsedforEvaluatingthePotentialRadiologicalConse-quencesofaLossofCoolantAccidentforBoilingWaterIForadditionalinformationconcerningthebasesfortheregula-torypositionspresentedinthisguide,seeNUREG/CR-2260,TechnicalBasisforRegulatoryGuide1.145.Reactors,andRegulatoryGuide1.4,AssumptionsUsedforEvaluatingthePotentialRadiologicalConsequencesofaLossofCoolantAccidentforPressurizedWaterReactors.Anumberofotherregulatoryguidesalsoincluderecom-mendationsfororreferencestoradiologicalanalysesofpotentialaccidents.Theapplicabilityofthespecificcriteriadiscussedhereintotheseotheranalyseswillbeconsideredonacase-by-casebasis.Untilsuchtimeasgenericguidelinesaredevelopedforsuchanalyses,themethodologyprovidedinthisguideisacceptabletotheNRCstaff.TheAdvisoryCommitteeonReactorSafeguardshas1*beenconsultedconcerningthisguideandhasconcurredintheregulatoryposition.B.DISCUSSIONTheatmosphericdiffusion2modelsdescribedinthisguidereflectreviewofrecentexperimentaldataondiffu-sionfromreleasesatgroundlevelatopensitesandfromreleasesatvariouslocationsonreactorfacilitybuildingsduringstableatmosphericconditionswithlowwindspeeds(Refs.Ithrough6).Thesetestsconfirmtheexistenceofeffluentplumemeanderduringlowwindspeedcondi-tionsandneutral(D)andstable(E,F,andG)atmosphericstabilityconditions(asdefinedbythetemperaturediffer-ence(AT)criteriainRegulatoryGuide1.23,OnsiteMeteorologicalPrograms,andprovidebasesforquantify-ingtheeffectsofplumemeanderoneffluentconcentra-tions.EffluentconcentrationsmeasuredoveraperiodofIhourundersuchconditionshavebeenshowntobesubstantiallylowerthanwouldbepredictedusingthetraditionalcurves(Ref.7)oflateralandverticalplumespread.Linesindicatesubstantivechangesfrompreviousissue.21ndiscussionsthroughoutthisregulatoryguide,atmosphericdispersionwillbeconsideredasconsistingoftwocomponents:atmospherictransportduetoorganizedormeanairflowwithintheatmosphereandamosphericdiffusionduetodisorganizedorrandomairmotions.Plumedepletionandsurfacedepositionofairbornematerialsarenotincludedinthedispersionmodelsdescibedinthisguide.USNRCREGULATORYGUIDESRegulatoryGuidesareissuedtodescribeandmakeavailabletothepublicmethodsacceptabletotheNRCstaffofimplementingspecificpartsoftheCommission'sregulations,todelineatetech-niquesusedbythestaffinevaluatingspecificproblemsorpostu-latedaccidentsortoprovideguidancetoapplicants.RegulatoryGuidesarenotsubstitutesforregulations,andcompliancewiththemisnotrequired.MethodsandsolutionsdifferentfromthosesetoutintheguideswillbeacceptableiftheyprovideabasisforthefindingsrequisitetotheissuanceorcontinuanceofapermitorlicensebytheCommission.Thisguidewasissuedafterconsiderationofcommentsreceivedfromthepublic.Commentsandsuggestionsforimprovementsintheseguidesareencouragedatalltimes,andguideswillberevised,asappropriate,toaccommodatecommentsandtoreflectnewinforma-tionorexperience.CommentsshouldbesenttotheSecretaryoftheCommission,U.S.NuclearRegulatoryCommission,Washington,D.C.20555,Attention:DocketingandServiceBranch.Theguidesareissuedinthefollowingtenbroaddivisions:1.PowerReactors6.Products2.ResearchandTestReactors7.Transportation3.FuelsandMaterialsFacilities8.OccupationalHealth4.EnvironmentalandSiting9.AntitrustandFinancialReview5.MaterialsandPlantProtection10.GeneralCopiesofIssuedguidesmaybepurchasedatthecurrentGovernmentPrintingOfficeprice.As