Computational analysis of electrorefiner for oxide-reduced LWR spent fuel

Electrorefining is a main unit process of pyroprocessing for the treatment of light-water reactor (LWR) spent fuel, where enhancing throughput is essential for practical deployment. This study presents a two-dimensional (2D) computational model to analyze anode dissolution, cathode deposition, and cathode scraping under realistic electrode configurations, considering the unique characteristics of electroreduction cathode baskets of pyroprocessing. Parametric simulations revealed that increasing the applied cell voltage greatly improved throughput, while raising the initial UCl 3 concentration had only a modest effect under the modeling conditions of this study. Electrode spacing required optimization between higher deposition rates at short gaps and longer scraping intervals at wider gaps. Undesirable uranium dendrite growth at the cathode tip was suppressed not only by insulating the cathode tip but also by adjusting the cathode length. The plate cathode exhibited a higher capacity for uranium deposition prior to scraping than the rod cathode. The application of parallel multi-electrode configurations was found to effectively increase electrorefiner throughput, and the gain was proportional to the number of facing electrode surfaces. The optimization results obtained for plate cathode-based parallel multi-electrode configurations provided valuable design guidance and are expected to contribute significantly to the practical deployment of pyroprocessing.