Pyrometallurgical partitioning of uranium and transuranic elements from rare earth elements by electrorefining and reductive extraction

High-level liquid waste generated from PUREX reprocessing contains a small amount of transuranic elements, such as Np, Pu, Am. and Cm, with long-lived radioactivities. A pyrometallurgical partitioning process is being develop ed to recover transuranic elements from such waste. Small amounts of U cont ained in the high-level liquid waste are also recovered in the process. A k ey issue for developing the process is effective separation of U and the tr ansuranic elements from the rare-earth elements, because the two elemental groups are chemically analogous. A series of process tests were carried out in the present study to demonstrate that a combination of electrorefining and reductive extraction is useful for separating U and transuranic element s from the rare-earth elements. The results indicate that 99% of U and each transuranic element is recovered by the combination process as a product, and that the quantity of rare-earth elements contained in the product is sm aller than the transuranic elements by weight. The overall mass balance of U and transuranic elements in the system ranged within the experimental err ors assigned to sampling and analysis.