The effect of oxychloride formation on the electroanalytical determination of chlorides in molten salts: an investigation of SmOCl in molten LiCl-KCl

Electroanalytical determination of chlorides in molten salts are often found to not have the accuracy needed for nuclear material monitoring. This was also observed in our studies on samarium trichloride. It was determined that a poorly soluble and relatively stable oxychloride that formed during our studies accounted for the loss of accuracy in the quantification of samarium trichloride. In this study, the spectroscopic and electrochemical properties of synthesized samarium oxychloride were investigated as they relate to the pyrochemical reprocessing of used nuclear fuel in the molten LiCl-KCl of eutectic composition. A qualitative, in situ investigation of oxychloride formation was conducted using electroanalytical voltammetry and Raman spectroscopy. These results were confirmed using synthesized oxychloride. The nature of oxychloride formation, solubility in the molten eutectic, implications in electrochemical processing, and the management of nuclear material in high-temperature systems are discussed.

Automated summary

Electroanalytical determination of chlorides in molten salts lacks the necessary accuracy for nuclear material monitoring, as observed in the studies on samarium trichloride. The formation of a poorly soluble and relatively stable oxychloride during the studies was identified as the cause of the accuracy loss. This study investigates the spectroscopic and electrochemical properties of synthesized samarium oxychloride in relation to the pyrochemical reprocessing of used nuclear fuel.