Development of transuranium elements recovery from high-level radioactive liquid waste

Abstract

The Transuranium Elements (TRUs) recovery process from High-Level Liquid Waste (HLLW) at a Purex reprocessing plant requires both simple processes and a high yield of TRUs recovery. This paper outlines a new TRUs recovery process which combines an aqueous process and a pyrochemical process. In the first step, TRUs and Rare Earth elements (REs) are precipitated from HLLW to separate alkali metal elements because the HLLW is an aqueous solution. It is difficult for TRUs to be separated simply from REs in the aqueous solution. A pyrochemical process is more effective to separate TRUs than an aqueous one. TRUs are separated from REs with an electrorefining process in molten salt in the final step. A tracer of Am was experimentally separated from a simulated HLLW at more than 99.5% yield in the oxalate precipitation. After the simulated HLLW was treated with the oxalate precipitation process, the precipitates were converted to their chlorides with hydrochloric acid and hydrogen peroxide below 100°C in 99.4% yield. Finally, Ce used to simulate TRUs was deposited on the cathode in order to study the separation from La used for REs with the electrorefining process in molten salt. The separation factor of TRUs from REs is estimated to be about 70.