Abstract
To develop an advanced technology which uses compacted equipment and generates less radioactive waste for reprocessing spent nuclear fuels, a new aqueous reprocessing system based on ion exchange separation has been studied. This process consists of (1) Pd removal by selective adsorption; (2) electrolytic reduction for the valence adjustment of U and some fission products such as Tc and Ru; (3) recovery of U, Pu and Np by anion exchange; and (4) separation of the long-lived minor actinides (Am, Cm) by extraction chromatography. For this process, we have prepared several novel anion exchangers and some chelating extraction-resins which are immobilized in porous silica particles. In this article, studies on the adsorption characteristics of various oxidation states of typical elements (nuclides) in spent nuclear from nitric acid solution with the anion exchangers are reviewed. Separation behavior of the nuclides in practical spent fuel solutions is demonstrated using the anion exchange columns. The results indicate that the proposed U and Pu recovery process is essentially feasible, although further works such as scale-up testing are needed.
