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【英文标准名称】:StandardTestMethodforNondestructiveAssayofRadioactiveMaterialbyTomographicGammaScanning
【原文标准名称】:使用层析成象γ扫描法对放射性物质进行无损分析的标准试验方法
【标准号】:ASTMC1718-2010
【标准状态】:现行
【国别】:美国
【发布日期】:2010
【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】:
【摘要】:TheTGSprovidesanondestructivemeansofmappingtheattenuationcharacteristicsandthedistributionoftheradionuclidecontentofitemsonavoxelbyvoxelbasis.TypicallyinaTGSanalysisaverticallayer(orsegment)ofanitemwillbedividedintoanumberofvoxels.Bycomparison,asegmentedgammascanner(SGS)candeterminematrixattenuationandradionuclideconcentrationsonlyonasegmentbysegmentbasis.Ithasbeensuccessfullyusedtoquantify238Pu,239Pu,and235U.SNMloadingsfrom0.5gto200gof239Pu(5,6),from1gto25gof235U(7),andfrom0.1to1gof238Puhavebeensuccessfullymeasured.TheTGStechniquehasalsobeenappliedtoassayingradioactivewastegeneratedbynuclearpowerplants(NPP).RadioactivewastefromNPPisdominatedbyactivationproducts(forexample,54Mn,58Co,60Co,110mAg)andfissionproducts(forexample,137Cs,134Cs).TheradionuclideactivitiesmeasuredinNPPwasteisintherangefrom3.7E+04Bqto1.0E+07Bq.SomeresultsofTGSapplicationtonon-SNMradionuclidescanbefoundintheliterature(8).TheTGStechniqueiswellsuitedforassayingitemsthathaveheterogeneousmatricesandthatcontainanon-uniformradionuclidedistribution.Sincetheanalysisresultsareobtainedonavoxelbyvoxelbasis,theTGStechniquecaninmanysituationsyieldmoreaccurateresultswhencomparedtoothergammaraytechniquessuchasSGS.Indeterminingtheradionuclidedistributioninsideanitem,theTGSanalysisexplicitlytakesintoaccountthecrosstalkbetweenvariousverticallayersoftheitem.TheTGSanalysistechniqueusesamaterialbasissetmethodthatdoesnotrequiretheusertoselectamassattenuationcurveapriori,providedthetransmissionsourcehasatleast2gammalinesthatspantheenergyrangeofinterest.AcommerciallyavailableTGSsystemconsistsofbuildingblocksthatcaneasilybeconfiguredtooperatethesystemintheSGSmodeorinafar-fieldgeometry.TheTGSprovides3-dimensionalmapsofgammarayattenuationandradionuclideconcentrationwithinanitemthatcanbeusedasadiagnostictool.Itempreparationislimitedtoavoidinglargequantitiesofheavilyattenuatingmaterials(suchasleadshielding)inordertoallowsufficienttransmissionthroughthecontainerandthematrix.1.1Thistestmethoddescribesthenondestructiveassay(NDA)ofgammarayemittingradionuclidesinsidecontainersusingtomographicgammascanning(TGS).Highresolutiongammarayspectroscopyisusedtodetectandquantifytheradionuclidesofinterest.Theattenuationofanexternalgammaraytransmissionsourceisusedtocorrectthemeasurementoftheemissiongammaraysfromradionuclidestoarriveataquantitativedeterminationoftheradionuclidespresentintheitem.1.2TheTGStechniquecoveredbythetestmethodmaybeusedtoassayscraporwastematerialincansordrumsinthe1to500litrevolumerange.Otheritemsmaybeassayedaswell.1.3ThetestmethodwillcovertwoimplementationsoftheTGSprocedure:(1)IsotopeSpecificCalibrationthatusesstandardsofknownradionuclidemasses(oractivities)todeterminesystemresponseinamass(oractivity)versuscorrectedcountratecalibration,thatappliestoonlythosespecificradionuclidesforwhichitiscalibrated,and(2)ResponseCurveCalibrationthatusesgammaraystandardstodeterminesystemresponseasafunctionofgammarayenergyandtherebyestablishescalibrationforallgammaemittingradionuclidesofinterest.1.4Thistestmethodwillalsoincludeatechniquetoextendth......
【中国标准分类号】:F46
【国际标准分类号】:27_120_30
【页数】:13P.;A4
【正文语种】:英语