RG1.003 BWR LOCA的潜在辐射后果评估所用的假设 1974

U.S.ATOMICENERGYCOMMISSIONREGULATORYDIRECTORATEOFREGULATORYSTANDARDSRevision2June1974GUIDEREGULATORYGUIDE1.3ASSUMPTIONSUSEDFOREVALUATINGTHEPOTENTIALRADIOLOGICALCONSEQUENCESOFALOSSOFCOOLANTACCIDENTFORBOILINGWATERREACTORSA.INTRODUCTIONSection50.34of10CFRPart50requiresthateachapplicantforaconstructionpermitoroperatinglicenseprovideananalysisandevaluationofthedesignandperformanceofstructures,systems,andcomponentsofthefacilitywiththeobjectiveofassessingtherisktopublichealthandsafetyresultingfromoperationofthefacility.Thedesignbasislossofcoolantaccident(LOCA)isoneofthepostulatedaccidentsusedtoevaluatetheadequacyofthesestructures,systems,andcomponentswithrespecttothepublichealthandsafety.Thisguidegivesacceptableassumptionsthatmaybeusedinevaluatingtheradiologicalconsequencesofthisaccidentforaboilingwaterreactor.Insomecases,unusualsitecharacteristics,plantdesignfeatures,orotherfactorsmayrequiredifferentassumptionswhichwillbeconsideredonanindividualcasebasis.TheAdvisoryCommitteeonReactorSafeguardshasbeenconsultedconcerningthisguideandhasconcurredintheregulatoryposition.B.DISCUSSIONAfterreviewinganumberofapplicationsforconstructionpermitsandoperatinglicensesforboilingwaterpowerreactors,theAECRegulatorystaffhasdevelopedanumberofappropriatelyconservativeassumptions,basedonengineeringjudgmentandonapplicableexperimentalresultsfromsafetyresearchprogramsconductedbytheAECandthenuclearindustry,thatareusedtoevaluatecalculationsofthediologicalconsequencesofvariouspostulatedaccidents.ThisguidelistsacceptableassumptionsthatmaybeusedtoevaluatethedesignbasisLOCAofaBoilingWaterReactor(BWR).Itshouldbeshownthattheoffsitedoseconsequenceswillbewithintheguidelinesof10CFRPart100.(Duringtheconstructionpermitreview,guideline,exposuresof20remwholebodyand150remthyroidshouldbeusedratherthanthevaluesgivenin§100.11inordertoallowfor(a)uncertaintiesinfinaldesigndetailsandmeteorologyor(b)newdataandcalculationaltechniquesthatmightinfluencethefinaldesignofengineeredsafetyfeaturesorthedosereductionfactorsallowedforthesefeatures.)C.REGULATORYPOSITION1.Theassumptionsrelatedtothereleaseofradioactivematerialfromthefuelandcontainmentareasfollows:a.Twenty-fivepercentoftheequilibriumradioactiveiodineinventorydevelopedfrommaximumfullpoweroperationofthecoreshouldbeassumedtobeimmediatelyavailableforleakagefromtheprimaryreactorcontainment.Ninety-onepercentofthis25percentistobeassumedtobeintheformofelementaliodine,5percentofthis25percentintheformofparticulateiodine,and4percentofthis25percentintheformoforganiciodides.b.Onehundredpercentoftheequilibriumradioactivenoblegasinventorydevelopedfrommaximumfullpoweroperationofthecoreshouldbeassumedtobeimmediatelyavailableforleakagefromthereactorcontainment.c.Theeffectsofradiologicaldecayduringholdupinthecontainmentorotherbuildingsshouldbetakenintoaccount.d.Thereductionintheamountofradioactivematerialavailableforleakagetotheenvironmentbycontainmentsprays,recirculatingfiltersystems,orotherengineeredsafetyfeaturesmaybetakenintoaccount,buttheamountofreductioninconcentrationofradioactivematerialsshouldbeevaluatedonanindividualcasebasis.e.TheprimarycontainmentshouldbeassumedtoleakattheleakrateincorporatedortobeincorporatedinthetechnicalspecificationsforthedurationoftheUSAECREGULATORYGUIDESCopiesofpublishedsnaybeobtainedbyrequestIndicatingthedivisionsdesiredtotheUS.AtomicEnergyCommission,Washington,D.C.20645,RegulatoryGuidesareissuedtodescobeandmalavailabletothePublicAttention:DirectorofRegulatoryStandrds.CommentsandsuggestionsformethodsacceptabletotheAECRegulatorystaffofimplementingspecificpartsofImprovementsInthesguidesweencouragedandshouldbesenttotheSecretarythsCommission'sregulations,todelineatetechniquesusedbythestaffinoftheCommission,US.AtomicEnergyCommission,Washington,D.C.20645,eveluatingspecificproblemsorpostulatediaccidents,ortoprovideguidancetoAttention:Chief,PublicProceedingsStaff.applicants.RegulatoryGuidesarenotsubstitutesforregulationsendcompliancewiththemisnotrequired.MethodsendsolutionsdifferentfromthornsetoutinTheauidesareissuedinthefollowingtenbroaddivisions:theguldeswillbeacceptableIftheyprovideabasisforthefindingsrequisitetotheissuanceorcontinuanceofapermitorlicensebytheCommission.1.PowerReactors6.Products2.ResearchandTestReactors7.Transportation3.FuelsandMaterialsFacilities8.OccupationalHealthPublishedguidewillberevisedperiodically,asappropriate,toaccommodate4.EnvironmentalandSiting9.AntitrustReviewcommentstoreflectnewinformationorexperience.5.MaterialsandPlantProtection10.Generalaccident.1Theleakageshouldbeassumedtopassdirectlytotheemergencyexhaustsystemwithoutmixing_2inthesurroundingreactorbuildingatmosphereandshouldthenbeassumedtobereleasedasanelevatedplumeforthosefacilitieswithstacks.'f.Nocreditshouldbegivenforretentionofiodineinthesuppressionpool.2.Acceptableassumptionsforatmosphericdiffusionanddoseconversionare:a.Elevatedreleasesshouldbeconsideredtobeataheightequaltonomorethantheactualstackheight.Certainsitedependentconditionsmayexist,suchassurroundingelevatedtopographyornearbystructureswhichwillhavet