阳离子交换树脂分离-ICP-MS法测定核纯级二氧化钍中的痕量硼

Determination of Boron at Trace Level in Nuclear Grade Thoria by ICP-MS After Separated by Cation Exchange Resin

摘要: 二氧化钍作为钍基熔盐固态堆的主要燃料，进堆前需严格控制中子吸收截面较大元素硼的含量。本工作针对核纯级二氧化钍中的痕量硼，以阳离子交换树脂Dowex 50W×8为分离纯化材料，以电感耦合等离子体质谱法（ICP-MS）为测量手段，建立了一种快速有效的分析方法。当二氧化钍称样量为0.3 g时，硼的检出限为0.016 μg/g，测得某核纯级二氧化钍样品中的硼含量为(0.111±0.007) μg/g，精密度6.2%（n=6），加标0.667 μg/g硼的回收率为91.4%（n=6）。该方法可有效将二氧化钍中的钍基体去除，从而实现痕量硼的准确测量。

Abstract: In thoria, the main fuel of solid thorium molten salt reactor, the content of boron must be strictly controlled since it has high neutron absorption cross section. In this paper, a rapid method of trace boron measurement in nuclear grade thoria was developed by ICP-MS after the separation of thorium by cation exchange resin. When the mass of thoria is 0.3 g, the detection limit of the methodology is found to be 0.016 μg/g, boron in a nuclear grade thoria is found to be (0.111±0.007) μg/g, while the precision and recovery of the methodology are found to be 6.2%(n=6) and 91.4%(n=6). With this method, the trace boron can be determined accurately after separating thorium in thoria effectively.