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

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.