Study on the time-dependent simulation and input parameter sensitivity of spent nuclear fuel electrorefining

A computer program for the simulation of spent nuclear fuel electrorefining has been developed based on general Butler–Volmer kinetics and mass transport within a diffusion layer model. The effect of a solid electrode area change due to the dissolution and deposition, the solubility of the element in the liquid Cd, and a volume change due to the development of metallic compounds were considered in this program. The program has been verified through Tomczuk et al.’s experiment, and the results show a good agreement of within 4 and 2 % for U amount in the anode and cathode, respectively. The sensitivity of several input parameters such as the standard electrode potential, activity coefficient, diffusion coefficient, diffusion layer thickness, and transfer coefficient has been tested. It was found that the standard electrode potential is very sensitive, as a 3 % variation leads to a U amount change of more than 30 and 50 % in the anode and molten salt, respectively. The sensitivity of the other input parameters is much less than the standard electrode potential, but significant within the data difference with the other references, except for the transfer coefficient. This result is useful for understanding the effectiveness of each input parameters on the simulation results.