ASTM E705-2008 用镎237的放射活化测定反应速率的标准试验方法
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【英文标准名称】:StandardTestMethodforMeasuringReactionRatesbyRadioactivationofNeptunium-237
【原文标准名称】:用镎237的放射活化测定反应速率的标准试验方法
【标准号】:ASTME705-2008
【标准状态】:现行
【国别】:美国
【发布日期】:2008
【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】:E10.05
【标准类型】:(TestMethod)
【标准水平】:()
【中文主题词】:
【英文主题词】:fissiondosimeter;fissionproduct;fissionreactionrates;Neptunium-237;Fastneutronflux/fluence;Neptunium-237;Neutronactivationreactions;Radioactivation--fastneutronflux;Thresholddetectors--0.7to6MeV
【摘要】:RefertoPracticeE261forageneraldiscussionofthedeterminationoffast-neutronfluenceratewithfissiondetectors.237Npisavailableasmetalfoil,wire,oroxidepowder.Forfurtherinformation,seeGuideE844.Itisusuallyencapsulatedinasuitablecontainertopreventlossof,andcontaminationby,the237Npanditsfissionproducts.Oneormorefissionproductscanbeassayed.PertinentdataforrelevantfissionproductsaregiveninTable1andTable2.137Cs-137mBaischosenfrequentlyforlongirradiations.Radioactiveproducts134Csand136Csmaybepresent,whichcaninterferewiththecountingofthe0.662MeV137Cs-137mBagammaray(seeTestMethodsE320).140Ba-140Laischosenfrequentlyforshortirradiations(seeTestMethodE393).95Zrcanbecounteddirectly,followingchemicalseparation,orwithitsdaughter95Nb,usingahigh-resolutiongammadetectorsystem.144Ceisahigh-yieldfissionproductapplicableto2-to3-yearirradiations.Itisnecessarytosurroundthe237Npmonitorwithathermalneutronabsorbertominimizefissionproductproductionfromtracequantitiesoffissionablenuclidesinthe237Nptargetandfrom238Npand238Pufrom(n,x03B3;)reactionsinthe237Npmaterial.Assayof238Puand239Puconcentrationisrecommendedwhenasignificantcontributionisexpected.Fissionproductproductioninalight-waterreactorbyneutronactivationproducts238Npand238Puhasbeencalculatedtobeinsignificant(1.2%),comparedtothatfrom237Np(n,f),foranirradiationperiodof12yearsatafastneutron(E>1MeV)fluencerateof1x00D7;1011cmx2212;2x00B7;sx2212;1,providedthe237Npisshieldedfromthermalneutrons(seeFig.2ofGuideE844).Fissionproductproductionfromphotonuclearreactions,thatis,(x03B3;,f)reactions,whilenegligiblenear-powerandresearchreactorcores,canbelargefordeep-waterpenetrations(1).Goodagreementbetweenneutronfluencemeasuredby237Npfissionandthe54Fe(n,p)54Mnreactionhasbeendemonstrated(2).Thereaction237Np(n,f)F.P.isusefulsinceitisresponsivetoabroaderrangeofneutronenergiesthanmostthresholddetectors.The237Npfissionneutronspectrum-averagedcrosssectioninseveralbenchmarkneutronfieldsaregiveninTable3ofPracticeE261.SourcesforthelatestrecommendedcrosssectionsaregiveninGuideE1018.Inthecaseofthe237Np(n,f)F.P.reaction,therecommendedcrosssectionsourceistheENDF/B-VIcrosssection(MAT=9346)revision1(3).Fig.1showsaplotoftherecommendedcrosssectionversusneutronenergyforthefast-neutronreaction237Np(n,f)F.P.Note18212;ThedataaretakenfromtheEvaluatedNuclearDatafile,ENDF/B-VI,ratherthanthelaterENDF/B-VII.ThisisinaccordancewithGuideE1018GuideforApplicationofASTMEvaluatedCrossSectionDataFile,6.1.sincethelaterENDF/B-VIIdatafilesdonotincludecovarianceinformation.Formoredetailss......
【原文标准名称】:用镎237的放射活化测定反应速率的标准试验方法
【标准号】:ASTME705-2008
【标准状态】:现行
【国别】:美国
【发布日期】:2008
【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】:E10.05
【标准类型】:(TestMethod)
【标准水平】:()
【中文主题词】:
【英文主题词】:fissiondosimeter;fissionproduct;fissionreactionrates;Neptunium-237;Fastneutronflux/fluence;Neptunium-237;Neutronactivationreactions;Radioactivation--fastneutronflux;Thresholddetectors--0.7to6MeV
【摘要】:RefertoPracticeE261forageneraldiscussionofthedeterminationoffast-neutronfluenceratewithfissiondetectors.237Npisavailableasmetalfoil,wire,oroxidepowder.Forfurtherinformation,seeGuideE844.Itisusuallyencapsulatedinasuitablecontainertopreventlossof,andcontaminationby,the237Npanditsfissionproducts.Oneormorefissionproductscanbeassayed.PertinentdataforrelevantfissionproductsaregiveninTable1andTable2.137Cs-137mBaischosenfrequentlyforlongirradiations.Radioactiveproducts134Csand136Csmaybepresent,whichcaninterferewiththecountingofthe0.662MeV137Cs-137mBagammaray(seeTestMethodsE320).140Ba-140Laischosenfrequentlyforshortirradiations(seeTestMethodE393).95Zrcanbecounteddirectly,followingchemicalseparation,orwithitsdaughter95Nb,usingahigh-resolutiongammadetectorsystem.144Ceisahigh-yieldfissionproductapplicableto2-to3-yearirradiations.Itisnecessarytosurroundthe237Npmonitorwithathermalneutronabsorbertominimizefissionproductproductionfromtracequantitiesoffissionablenuclidesinthe237Nptargetandfrom238Npand238Pufrom(n,x03B3;)reactionsinthe237Npmaterial.Assayof238Puand239Puconcentrationisrecommendedwhenasignificantcontributionisexpected.Fissionproductproductioninalight-waterreactorbyneutronactivationproducts238Npand238Puhasbeencalculatedtobeinsignificant(1.2%),comparedtothatfrom237Np(n,f),foranirradiationperiodof12yearsatafastneutron(E>1MeV)fluencerateof1x00D7;1011cmx2212;2x00B7;sx2212;1,providedthe237Npisshieldedfromthermalneutrons(seeFig.2ofGuideE844).Fissionproductproductionfromphotonuclearreactions,thatis,(x03B3;,f)reactions,whilenegligiblenear-powerandresearchreactorcores,canbelargefordeep-waterpenetrations(1).Goodagreementbetweenneutronfluencemeasuredby237Npfissionandthe54Fe(n,p)54Mnreactionhasbeendemonstrated(2).Thereaction237Np(n,f)F.P.isusefulsinceitisresponsivetoabroaderrangeofneutronenergiesthanmostthresholddetectors.The237Npfissionneutronspectrum-averagedcrosssectioninseveralbenchmarkneutronfieldsaregiveninTable3ofPracticeE261.SourcesforthelatestrecommendedcrosssectionsaregiveninGuideE1018.Inthecaseofthe237Np(n,f)F.P.reaction,therecommendedcrosssectionsourceistheENDF/B-VIcrosssection(MAT=9346)revision1(3).Fig.1showsaplotoftherecommendedcrosssectionversusneutronenergyforthefast-neutronreaction237Np(n,f)F.P.Note18212;ThedataaretakenfromtheEvaluatedNuclearDatafile,ENDF/B-VI,ratherthanthelaterENDF/B-VII.ThisisinaccordancewithGuideE1018GuideforApplicationofASTMEvaluatedCrossSectionDataFile,6.1.sincethelaterENDF/B-VIIdatafilesdonotincludecovarianceinformation.Formoredetailss......
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