Estimation of Material Balance in Pyrometallurgical Partitioning Process of Transuranic Elements from High-level Liquid Waste

Abstract

A pyrometallurgical partitioning process for transuranic elements (TRUs) from high-level liquid waste (HLLW) has been studied to develop an effective and safety method of nuclear waste disposal. A salt and metal as solvents, Li as reductant and chlorine gas can be recycled in the process. The process is expected to generate less secondary radioactive waste because of no irradiation damage of the solvents, and to require a relatively compact installation because of larger critical mass in comparison with a conventional aqueous method.

In this study, the material balance of the solutes and the volume of the solvents were estimated in the pyrometallurgical partitioning process that was constructed on the basis of our previous study. The results show that the volume of the salt as solvent is about 200 l and that of Cd, Bi and Pb as metal solvent is 54, 71 and 140 l, respectively, in the case that HLLW from PUREX reprocessing of 1t LWR spent fuel is treated in the process. The results also show that the amount of Li in the waste salt disposed from the process is kept less than the amount of Li₂O needed for glass matrix.

KEYWORDS:

• pyrometallurgy
• pyrometallurgical partitioning
• high-level liquid wastes
• transuranic elements, fission products
• molten salts
• liquid metals
• denitration
• chlorination
• reductive-extraction
• counter-current extraction
• electrolysis