有源符合中子法测量材料中的高浓铀  

MEASUREMENT OF HIGHLY ENRICHED URANIUM IN SOME MATERIALS WITH ACTIVE COINCIDENCE NEUTRON COUNT

作　　者：王效忠[1] 贾向军[1] 赵荣生[1] 张文良[1] 乔盛忠[1] 杨留成[1] 许晓东 李泽[1] 

机构地区：[1]中国原子能科学研究院放射化学研究所

出　　处：《原子能科学技术》1998年第3期256-262,共7页Atomic Energy Science and Technology

基　　金：核工业基金资助项目

摘　　要：研究了有源符合中子法测量不同试样中高浓铀的方法和技术。将１个高计数率符合中子计数器改装为有源井型符合中子计数器装置，测量由Ａｍ－Ｌｉ中子源发射的中子诱发物料中的２３５Ｕ裂变时产生的裂变中子，以确定物料中２３５Ｕ含量。用Ｕ３Ｏ８粉末工作样品进行了探测效率刻度，在５００ｇＵ３Ｏ８粉末范围内，以快中子方式测量的刻度曲线近似线性。实测了含铀粉末不同形态、氧化程度各异的多种试样，给出了试样的形态、密度、碳含量及轴向和径向分布不均匀性等因素引起的各种误差，并进行了实验校正。实验结果表明：测量误差在４％—１１％之间，大部分数据与常规重量法在９％内符合。试样中碳含量对测量结果影响较大。The technique for measuring highly enriched uranium (HEU)in some samples are described in the paper. The high level neutron coincidence counter is modified into an active well neutron coincidence counter using two Am Li neutron sources. The fission neutron of HEU induced by neutron of Am Li source is measured for determining the 235 U content in material, the calibration function is determined with U 3O 8 powder, the function between the real coincidence counts and mass of U 3O 8 powder under 500 g is approximately linear with a fast neutron mode measurement. The U content in some materials are determined and the corrections about their density, matrix(mainly carbon), the material position etc are discussed. The most of the measurement uncertainty is 4 %—11 %. The carbon in material is one of the most important interference source.

关 键 词：有源符合中子法 中子源 含铀物料 铀235 

分 类 号：TL271.6[核科学技术—核燃料循环与材料]