Determination of primary metal elements in LiF-UF4 and LiF-ThF4 molten salts via inductively coupled plasma atomic emission spectrometry

Abstract

BackgroundLiF-UF4 and LiF-ThF4 are used as addition salts in thorium-based molten salt nuclear reactors. Monitoring the product quality during the preparation of molten salts necessitates the analysis of the contents of the main metal elements in LiF-UF4 and LiF-ThF4, namely, lithium, uranium, and thorium.PurposeThis study aims to establish effective, rapid analysis methods for determination of primary metal elements in LiF-UF4 and LiF-ThF4 molten salts.MethodsFirstly, the LiF-UF4 samples were treated with nitric acid and hydrogen peroxide whilst the LiF-ThF4 samples were dissolved in aluminum nitrate. Then, inductively coupled plasma atomic emission spectrometry was used as rapid analysis methods for measuring these two molten salts, and manganese was employed as the internal standard element to reduce the effect of signal drift.ResultsIn the analytical method of LiF-UF4, the recoveries of Li and U are detected to be 99.6%~102.4% and 99.6%~101.8%, respectively. The relative standard deviations (RSDs) of Li and U are 0.2%~0.7%, and 1.1%~2.0%, respectively. In the analytical method of LiF-ThF4, the recoveries of Li and Th are detected to be 99.6%~102.3% and 99.6%~102.4%, respectively. The relative standard deviations of Li and Th are 1.9%~2.0%, and 0.3%~0.4%, respectively.ConclusionsThe proposed methods are simple, time-efficient, accurate, and suitable for rapid analyses of large numbers of samples.

Keywords

• lif-uf4
• lif-thf4
• icp-aes
• lithium
• uranium
• thorium