【英文标准名称】:StandardTestMethodforMeasuringReactionRatesbyRadioactivationofUranium-238
【原文标准名称】:用铀238的放射活化测定反应速率的测试方法
【标准号】:ASTME704-2008
【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】:Neutronactivationreactions;Radioactivation--fastneutronflux;Thresholddetectors--1.5to7MeV;Uranium;Uranium-238;Fastneutronflux/fluence;Neutronactivationreactions;Radioactivation--fastneutronflux;Thresholddetectors--1.5to7MeV;Uran
【摘要】:RefertoPracticeE261forageneraldiscussionofthedeterminationoffast-neutronfluenceratewithfissiondetectors.238Uisavailableasmetalfoil,wire,oroxidepowder(seeGuideE844).Itisusuallyencapsulatedinasuitablecontainertopreventlossof,andcontaminationby,the238Uanditsfissionproducts.Oneormorefissionproductscanbeassayed.PertinentdataforrelevantfissionproductsaregiveninTable1andTable2.137Cs-137mBaischosenfrequentlyforlongirradiations.Radioactiveproducts134Csand136Csmaybepresent,whichcaninterferewiththecountingofthe0.662MeV137Cs-137,Bagammarays(seeTestMethodsE320).140Ba-140Laischosenfrequentlyforshortirradiations(seeTestMethodE393).95Zrcanbecounteddirectly,followingchemicalseparation,orwithitsdaughter95Nbusingahigh-resolutiongammadetectorsystem.144Ceisahigh-yieldfissionproductapplicableto2-to3-yearirradiations.Itisnecessarytosurroundthe238Umonitorwithathermalneutronabsorbertominimizefissionproductproductionfromaquantityof235Uinthe238Utargetandfrom239Pufrom(n,x03B3;)reactionsinthe238Umaterial.Assayofthe239Puconcentrationwhenasignificantcontributionisexpected.Fissionproductproductioninalight-waterreactorbyneutronactivationproduct239Puhasbeencalculatedtobeinsignificant(x003C;2%),comparedtothatfrom238U(n,f),foranirradiationperiodof12yearsatafast-neutron(E>1MeV)fluencerateof1x00D7;1011cmx2212;2x00B7;sx2212;1providedthe238Uisshieldedfromthermalneutrons(seeFig.2ofGuideE844).Fissionproductproductionfromphotonuclearreactions,thatis,(x03B3;,f)reactions,whilenegligiblenear-powerandresearch-reactorcores,canbelargefordeep-waterpenetrations(1).1.1Thistestmethodcoversproceduresformeasuringreactionratesbyassayingafissionproduct(F.P.)fromthefissionreaction238U(n,f)F.P.1.2Thereactionisusefulformeasuringneutronswithenergiesfromapproximately1.5to7MeVandforirradiationtimesupto30to40years.1.3EquivalentfissionneutronfluenceratesasdefinedinPracticeE261canbedetermined.1.4Detailedproceduresforotherfast-neutrondetectorsarereferencedinPracticeE261.1.5ThevaluesstatedinSIunitsaretoberegardedasstandard.Nootherunitesofmeasurementareincludedinthisstandard.1.6Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappropriatesafetyandhealthpracticesanddeterminetheapplicabilityofregulatorylimitationspriortouse.
【中国标准分类号】:F46
【国际标准分类号】:27_120_30
【页数】:4P.;A4
【正文语种】:英语