【英文标准名称】:StandardTestMethodforNon-DestructiveAssayofNuclearMaterialinWastebyPassiveandActiveNeutronCountingUsingaDifferentialDie-AwaySystem
【原文标准名称】:用差动衰减系统钝化-活化中子计数法对废物中的核物质进行无损分析的标准试验方法
【标准号】:ASTMC1493-2001
【标准状态】:现行
【国别】:
【发布日期】:2001
【实施或试行日期】:
【发布单位】:美国材料与试验协会(US-ASTM)
【起草单位】:C26.10
【标准类型】:(TestMethod)
【标准水平】:()
【中文主题词】:
【英文主题词】:non-destructiveassay;nuclearmaterialsinwaste;passiveandactiveneutroncounting;differentialdie-awaysystem;uranium;plutonium
【摘要】:1.1Thistestmethodcoversasystemthatperformsnondestructiveassay(NDA)ofuraniumorplutonium,orboth,usingtheactive,differentialdie-awaytechnique(DDT),andpassiveneutroncoincidencecounting.Resultsfromtheactiveandpassivemeasurementsarecombinedtodeterminethetotalamountoffissileandspontaneously-fissioningmaterialindrumsofscraporwasteaslargeas208L.Correctionsaremadetothemeasurementsfortheeffectsofneutronmoderationandabsorption,assumingthattheeffectsareaveragedoverthevolumeofthedrumandthatnosignificantlumpsofnuclearmaterialarepresent.Thesesystemsaremostwidelyusedtoassaylow-levelandtransuranicwaste,butmayalsobeusedforthemeasurementofscrapmaterials.Whilethistestmethodisspecifictothesecond-generationLosAlamosNationalLaboratory(LANL)passive-activeneutronassaysystem,theprincipleappliestootherDDTsystems.1.1.1Intheactivemode,thesystemmeasuresfissileisotopessuchas235Uand239Pu.Theneutronsfromapulsed,14-MeVneutrongeneratorarethermalizedtoinducefissionintheassayitem.Betweengeneratorpulses,thesystemdetectsprompt-fissionneutronsemittedfromthefissilematerial.Thenumberofdetectedneutronsbetweenpulsesisproportionaltothemassoffissilematerial.Thismethodiscalledthedifferentialdie-awaytechnique.1.1.2Inthepassivemode,thesystemdetectstime-coincidentneutronsemittedfromspontaneouslyfissioningisotopes.Theprimaryisotopesmeasuredare238Pu,240Pu,and242Pu;however,thesystemmaybeadaptedforuseonotherspontaneously-fissioningisotopesaswell.Thenumberofcoincidentneutronsdetectedisproportionaltothemassofspontaneously-fissioningmaterial.1.2Theactivemodeisusedtoassayfissilematerialinthefollowingranges.1.2.1Foruranium-bearingitems,theDDTcanmeasurethe235Ucontentintherangefrom0.02toover100g.Normally,theassayofitemsbearingonlyuraniumisperformedusingmatrix-specificcalibrationstoaccountfortheeffectofthematrixontheactivesignal.1.2.2Forplutonium-bearingitems,theDDTmethodmeasuresthe239Pucontentintherangebetween0.01and20g.1.3Thepassivemodeiscapableofassayingspontaneously-fissioningnuclei,overanominalrangefrom0.05to15gof240Pu,orequivalent.Thepassivemodecanalsobeusedtomeasurelarge(forexample,kg)quantitiesof238U.1.4Thistestmethodrequiresknowledgeoftherelativeabundancesoftheplutoniumoruraniumisotopestodeterminethetotalplutoniumoruraniummass.1.5Thistestmethodwillgivebiasedresultswhenthewasteformdoesnotmeetthecalibrationspecificationsandthemeasurementassumptionspresentedinthistestmethodregardingtherequirementsforahomogeneousmatrix,uniformsourcedistribution,andtheabsenceofnuclearmateriallumps,totheextentthattheyeffectthemeasurement.1.6Thecompleteactiveandpassiveassayofa208Ldrumisnominally10minorless.1.7Improvementstothistestmethodhavebeenreported(1,2,3,4).Discussionsoftheseimprovementsarenotincludedinthistestmethod.1.8Thisstandardmayinvolvehazardousmaterials,operations,andequipment.Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappropriatesafetyandhealthpracticesanddeterminetheapplicabilityofregulatorylimitationspriortouse.SpecificprecautionarystatementsaregiveninSection8.
【中国标准分类号】:F40
【国际标准分类号】:27_120_30
【页数】:15P.;A4
【正文语种】: