Evaluation of Cadmium Pool Potential in a Electrorefiner with Ceramic Partition for Spent Metallic Fuel

摘要

A new electrorefiner (ER) with a ceramic partition has been developed for the pyrometallurgical reprocessing of metallic fuel. This ER has anode and cathode salt regions which are separated by a ceramic partition. They are electrically connected via a cadmium pool (Cd pool) at the bottom of the cell. One of the concerns with this ER configuration is increase of electric resistance in the cell (cell resistance) caused by the ceramic partition. The DEVON code, which was developed to calculate cell resistance by calculating the potential distribution in the bulk salt region using the Finite Element Method, was modified to evaluate the potential of the Cd pool which acts as an intermediate electrode between the anode and the cathode. A series of experiments was performed to measure the potential. It was found that the calculated potential agreed very well with the experimental results under good agitation condition. The effects of lithium reduction in the Cd pool due to its lower activity coefficient in cadmium were found to be significant. As an application of the code to ER design, the cell resistance increase caused by adding the partition was shown to be minimized.