Thermodynamic properties of actinides and rare earths in molten salt and cadmium, and prediction of separation efficiency

The pyrometallurgical process is being developed to recover transuranium elements (TRUs) from PUREX wastes. This process consists of(1) microwave denigration and solidification to convert aqueous wastes to dry oxides, (2) chlorination to convert oxides to chlorides, (3) reductive extraction to partition TRUs into liquid cadmium from molten chlorides and (4) electrorefining to purify TRUs recovered. It is expected that TRUs obtained by electrorefining contain some amount of rare earths (REs), because of the chemical similarity to TRUs and the existence by 10 times as much as TRUs in Purex wastes. Thermodynamic properties of TRUs and REs in molten salt / liquid cadmium have been measured to evaluate the separation efficiency of TRUs in the design study of pyrometallurgical process. (authors)