Modeling temperature distribution in an electrolytic reducer considering decay and salt resistive heat effects

Pyroprocessing for the recycling of LWR spent nuclear fuel includes an electrolytic reduction process that converts oxides into metals. To commercialize pyroprocessing, it is essential to ensure the long-term operability of the electrolytic reducer, which operates under the most severe conditions of the electrochemical processes of pyroprocessing. This study established the appropriate operating temperature range for the electrolytic reducer and investigated the effects of decay heat and salt resistive heat on the temperature distribution of the electrolytic reducer by COMSOL modeling. As the system operates over an extended period, the heat generation due to the decay heat becomes more significant than the salt resistive heat and the temperature of the molten salt electrolyte of the general structure of the electrolytic reducer exceeded the optimal temperature range. To address this issue, heat conduction plates were added to connect the molten salt layer and the upper part of the electrolytic reducer. Heat conduction plates enhanced heat transfer from the molten salt layer to the system's surroundings. As a result, it was concluded that the electrolytic reducer could be operated within the optimal temperature range despite the heat generation by both decay and salt resistive heat.