ASTM C1493-2009 用微分衰减系统钝化-活化中子计数法对废物中的核物质进行无损化验的标准试验方法

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【英文标准名称】:StandardTestMethodforNon-DestructiveAssayofNuclearMaterialinWastebyPassiveandActiveNeutronCountingUsingaDifferentialDie-AwaySystem
【原文标准名称】:用微分衰减系统钝化-活化中子计数法对废物中的核物质进行无损化验的标准试验方法
【标准号】:ASTMC1493-2009
【标准状态】:现行
【国别】:
【发布日期】:2009
【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】:微分衰减系统;中子计数;核废物和废弃材料;无源中子计数
【英文主题词】:Differentialdie-awaysystem;Neutroncounting;Nuclearscrapandwastematerials;Passiveneutroncounting
【摘要】:Thistestmethodisusefulforquantifyingfissile(forexample,233U,235U,239Puand241Pu)andspontaneously-fissioningnuclei(forexample,238Pu,240Pu,242Pu,244Cm,248Cm,and252Cf)inwasteandscrapdrums.Totalelementalmassoftheradioactivematerialscanbecalculatediftherelativeabundancesofeachradionuclideareknown.Typically,thistestmethodisusedtomeasureonefissileisotope(forexample,235Uor239Pu).Thistestmethodcanbeusedtosegregatelowlevelandtransuranicwasteatthe100nCi/gconcentrationlevelcurrentlyrequiredtomeettheDOEWasteIsolationPilotPlant(WIPP)wasteacceptancecriterion(5,8,9).Thistestmethodcanbeusedforwastecharacterizationtodemonstratecompliancewiththeradioactivitylevelsspecifiedinwaste,disposal,andenvironmentalregulations(SeeNRCregulatoryguides,DOEOrder435.1,10CFRPart71,40CFRPart191,andDOE/WIPP-069).Intheactivemode,theDDTsystemcanmeasurethe235Ucontentintherangefromx003C;0.02to>100gandthe239Pucontent,nominallybetweenx003C;0.01and>20g.Inthepassivemode,theDDTsystemiscapableofassayingspontaneously-fissioningnuclei,overanominalrangefrom0.05to15gof240Pu,orequivalent(5,10,11,12,13).Thistestmethodshouldbeusedinconjunctionwithawastemanagementplanthatsegregatesthecontentsofassayitemsintomaterialcategoriesaccordingtosomeorallofthefollowingcriteria:bulkdensityofthewaste,chemicalformsoftheplutoniumoruraniumandmatrix,(x03B1;,n)neutronintensity,hydrogen(moderator)andabsorbercontent,thicknessoffissilemass(es),andtheassayitemcontainersizeandcomposition.Eachmatrixmayrequireadifferentsetofcalibrationstandardsandmayhavedifferentmasscalibrationlimits.Theeffectonthequalityoftheassay(thatis,minimizingprecisionandbias)cansignificantlydependonthedegreeofadherencetothiswastemanagementplan.Thebiasofthemeasurementresultsisrelatedtothefillheight,thehomogeneityandcompositionofthematrix,thequantityanddistributionofthenuclearmaterial,andtheitemsize.Theprecisionofthemeasurementresultsisrelatedtothequantityofthenuclearmaterial,thebackground,andthecounttimeofthemeasurement.Forbothmatrix-specificandwide-rangecalibrations,thistestmethodassumesthecalibrationmaterialmatchestheitemstobemeasuredwithrespecttohomogeneityandcompositionofthematrix,theneutronmoderatorandabsorbercontent,andthequantity,distribution,andformofnuclearmaterial,totheextenttheyaffectthemeasurement.Thealgorithmsforthistestmethodassumehomogeneity.Heterogeneityinthedistributionofnuclearmaterial,neutronmoderators,andneutronabsorbershasthepotentialtocausebiasedresults(14).Thistestmethodassumesthatthedistributionofthecontributingradioisotopesisuniformthroughoutthecontainerandthatlumpsofnuclearmaterialarenotpresent.ReliableresultsfromtheapplicationofthistestmethodrequirewastetobepackagedsotheconditionsofSection5.5canbemet.Insomecases,site-specificrequirementswilldictatethepackagingrequirementswithpossibledetrimentaleffectstothemeasurementresults.Boththeactivemodeandthepassivemodeprovideassayvaluesforplutonium.Duringthecalibrationprocess,theoperatorshoulddeterminetheapplicablemassrangesforbothmodesofoperation.1.1Thistestmethodcoversasy......
【中国标准分类号】:F40
【国际标准分类号】:27_120_30
【页数】:13P.;A4
【正文语种】: