摘要
在核事故的条件下,边界土壤中的放射性分布难以确定,需研制一种含60Co、90Sr、137Cs、241Am等多种放射性核素的土壤标准物质,用于分析过程中的监督和校准。由于满足条件的受偶然放射性污染的土壤较难寻找,故采用人工添加目标放射性核素的方法制备放射性土壤标准物质。在制备过程中,土壤局部组成和颗粒大小的差异对所添加核素的吸附差别可能形成所谓的"热点",造成最终标准物质的均匀性检验无法通过。为解决该难题,选择几个核素进行逐级添加与稀释制备土壤标准物质,并研究其在不同步骤中如溶液和固体粉末混合时和固体粉末的逐级稀释时的均匀性。通过单因素方差分析方法的检验证明,在制备方法进行改进后其均匀性满足要求,为下一步的正式制备奠定基础。
[Background] Under the condition of nuclear accident, the distribution of radioactivity in the boundary soil is difficult to be determined. It is necessary to develop a reference soil that has a variety of radionuclides such as 60Co, 90Sr, 137Cs, 241Am, and so on. [Purpose] Due to the fact that the soil contaminated by accidental radioactivity is difficult to find, it is proposed to use artificial addition of radionuclides to prepare the reference soil. [Methods] The difference in the local composition of the soil and the difference in particle size with respect to the adsorption of radionuclide may form a so-called ＂hot spot＂, resulting in inhomogeneity. In order to solve this problem, three nuclides 60Co, 90Sr and 137Cs are selected for the preparation with stepwise addition method. [Results] Three groups and eighteen times of measurement data for each nuclide were calculated in a homogeneity test with F-value exam. The result is F≤Fa, which meets the requirements. [Conclusion] The homogeneity of the reference material can be solved by an improvement method： 1） changing the aqueous solution to an organic-aqueous solution in the first step of mixing; 2） using a ball milling mixing method instead of the three-dimensional mixing method in the mixing of the soil nowders.
作者
徐利军
叶宏生
刁立军
张卫东
罗瑞
李明
林敏
宋鑫鹏
夏文
陈义珍
肖振红
陈克胜
XU Lijun;YE Hongsheng;DIAO Lijun;ZHANG Weidong;LUO Rui;LIMing;LIN Min;SONG Xinpeng;XIAWen;CHEN Yizhen;XIAO Zhenhong;CHEN Kesheng(National Key Laboratory for Metrology and Calibration Techniques,China Institute of Atomic Energy,Beijing 102413,China)
出处
《核技术》
CAS
CSCD
北大核心
2018年第9期55-60,共6页
Nuclear Techniques
关键词
标准物质
放射性“热点”
混合
均匀性
检验
Reference material
Radioactive ＂hot spots＂
Mix
Homogeneity
Test
