主动式多重性方法对黄饼中铀定量的模拟研究  

Simulation study of uranium content in uranium yellow cake using the active multiplicity method

作　　者：张浩然 张焱 胡文兴 瞿金辉[2] 刘世梁 王仁波[2,3] ZHANG Haoran;ZHANG Yan;HU Wenxing;QU Jinhui;LIU Shiliang;WANG Renbo(Fundamental Science on Radioactive Geology and Exploration Technology Laboratory,East China University of Technology,Nanchang 330013,China;Engineering Research Center for Nuclear Technology Application,Ministry of Education,East China University of Technology,Nanchang 330013,China;Pan-China Detect Technology Co.,Ltd.,Nanchang 330013,China)

机构地区：[1]东华理工大学放射性地质与勘探技术国防重点学科实验室,南昌330013 [2]东华理工大学核技术应用教育部工程研究中心,南昌330013 [3]泛华检测技术有限公司,南昌330013

出　　处：《核技术》2024年第2期49-57,共9页Nuclear Techniques

基　　金：国家自然科学基金(No.42374226);江西省自然科学基金项目(No.20232BAB201043);江西省学科学术和技术带头人培养项目(No.20232BCJ23006);国防科工局"十三五"核能开发项目子课题(No.20201192-01);放射性地质与勘探技术国防重点学科实验室(No.2022RGET20);核技术应用教育部工程研究中心开放基金(No.HJSJYB2020-1)资助。

摘　　要：黄饼材料中铀的准确定量是后续处理工艺选择的关键,文中在主动式多重性方法的基础上,提出了一种通过记录分析中子源诱发238U裂变信息,进行铀定量的方法。但由于黄饼材料自身存在中子自屏蔽效应以及含水量的差异,导致定量结果存在偏差。为了进一步提高定量准确性,使用MCNP(Monte Carlo N-Particle Transport)结合MATLAB程序优化选择了241Am-Be源作为激发源;另外,通过对不同质量及含水量系列化样品的模拟发现:铀定量误差主要来自于泄漏增殖因子ML与增殖因子M差距的不匹配。通过MCNP模拟获取M随铀质量变化规律的曲线后,根据样品净含量选择合适的增殖因子M,再根据二重计数率D进行定量计算,获得铀定量的相对误差小于5%;含水量的变化带来的中子自屏蔽效应对多重计数率影响较大,通过S0/Si与D0/Di的关系对二重计数率D进行修正后再进行计算,铀定量的相对误差能够控制在10%左右;该研究对中子多重性方法在黄饼生产与测量中的应用推广具有重要的参考价值。[Background]Accurately quantifying the uranium in uranium yellow cake material is the key to selecting the subsequent processing technology.As an essential nondestructive testing method for uranium-containing materials,the active multiplicity method is proposed to quantify uranium by recording and analyzing 238U fission information induced by neutron sources.However,the quantitative results are biased owing to the neutron selfshielding of the uranium yellow cake material itself and differences in water content between samples.[Purpose]This study aims to rapidly measure the uranium content of uranium yellow cake material using active multiplicity method and further improve of measurement accuracy.[Methods]First of all,following the comparison of the excitation effects of different neutron sources on a sample using the MCNP(Monte Carlo N-Particle Transport)program,a 241Am-Be source was selected to simulate the sample measurement process and optimized using MATLAB programming combined with MCNP.Then,the curve of multiplication factor M versus the uranium mass was obtained by simulation,and an appropriate M was selected according to the net content of the sample.Finally,the quantitative error caused by the difference between neutron absorption and water content in the process was investigated,and the double rate was corrected using the relationship between S0/Si and D0/Di and then calculated.[Results]The simulation results of a series of samples with different masses and water contents show that a large gap is found between M and the leakage multiplication factor ML caused by neutron self-shielding.The error in uranium quantification is less than 5%;neutron self-shielding due to the change in water content affects the single,double,and triple counting rates(S/D/T).The relative error of uranium quantification can be controlled at around 10%.[Conclusions]This study has significance and important reference value for further research on the application of the active multiplicity method in the production and measurement o

关 键 词：中子多重性 黄饼 238U 中子自屏蔽 模拟仿真 

分 类 号：TL84[核科学技术—核技术及应用]