总中子法在钚溶液系统浓度测量中的应用研究  

Study on the Application of Total Neutron Counting in the Assay of Plutonium Solution Concentration

作　　者：赵子凡 梁庆雷[2] 杨海峰 霍小东 刘国荣[2] 李井怀[2] ZHAO Zifan;LIANG Qinglei;YANG Haifeng;HUO Xiaodong;LIU Guorong;LI Jinghuai(China Nuclear Power Engineering Co.,Ltd.,Beijing 100840,China;China Institute of Atomic Energy,Beijing 102413,China)

机构地区：[1]中国核电工程有限公司,北京100840 [2]中国原子能科学研究院,北京102413

出　　处：《核科学与工程》2021年第6期1297-1302,共6页Nuclear Science and Engineering

摘　　要：目前被动中子法在国外钚浓度在线监测中应用较多,我国对于此项技术在钚溶液系统浓度测量中的研究则相对较少。钚溶液中的自发裂变中子和(α,n)中子,部分在慢化过程中直接被吸收,部分经慢化、吸收、裂变释放出诱发裂变中子,部分逃脱吸收最终泄漏出溶液系统,在中子探测器中形成计数,原则上可由“点模型”方程推算出溶液中的钚浓度。本文以钚溶液系统为对象,开展了总中子计数法推算钚浓度的研究,深入探讨了钚同位素组成比例和钚溶液中(α,n)中子的影响,实现了钚浓度计算程序。设计并搭建了验证实验,使用^(3)He探测器和涂硼探测器实测了7个不同浓度的钚溶液样品的总中子计数率,钚浓度计算程序给出的钚浓度值与化学标定值符合良好。结果表明,考虑了钚溶液中(α,n)中子和钚同位素组成比例的影响后,利用基于“点模型”方程的总中子法进行钚浓度分析具有很好的精度,为后续进一步将中子法应用于钚浓度在线监测打下了良好的基础。At present,the passive neutron counting has been widely used abroad for the non-destructive assay of plutonium inventory,but China has little study on its application in the plutonium solution concentration assay.There are spontaneous fission neutrons and(α,n)neutrons in the solution,part of which are absorbed when moderated,part of which are moderated,absorbed,and finally fission neutrons are released,and part of which finally leak out of the solution and can be detected by the outside neutron detector,in principle the plutonium concentration can be calculated using the’point model’equation based on the neutron counting.In this paper,the total neutron counting is used to estimate the plutonium concentration for a plutonium solution system,the influence of plutonium isotopic composition and of(α,n)neutrons was fully studied,and finally a code was implemented for the plutonium concentration calculation.In order to verify the algorithm,an experiment was designed and carried out.The total neutron counting of 7 plutonium solution samples of different concentrations were measured by^(3)He detector and boron-lined detector.The plutonium concentrations calculated by the code were in good agreement with the chemical assay values.The results showed that,taking into account the influence of plutonium isotopic composition and of(α,n)neutrons,the plutonium concentration from total neutron counting based on‘point model’equation had a good accuracy with the chemical assay value,which laid a good foundation for further application of neutron counting in the online plutonium solution concentration assay.

关 键 词：总中子法 溶液系统 钚浓度分析 点模型方程 

分 类 号：TL81[核科学技术—核技术及应用]