Theoretical Consideration and Recent Progress of Chemical Enrichment Process for Uranium Enrichment

Abstract

Research and development for uranium enrichment by oxidation-reduction chromatography, begun in 1972 despite the prevailing view that a chemical process would require several centuries of operation to attain fuel-grade uranium enrichment and would thus be impractical, led to the establishment of basic process technology permitting attainment of 3% enrichment within several months of operation by the mid 1980, through advance which brought increased electron exchange and oxidation-reduction reaction rates, effective uranium adsorption band formation and maintenance, and equilibrium plate height reductions based on elucidation of mobile-phase dispersion. Theoretical descriptions of the enrichment factor and the isotopic abundance curve of the adsorption band were developed, and the theoretical and experimental development and verification of an intracolumn mechanism of redox agent self-regeneration led to a new “Super” process version characterized by greater simplicity and efficiency than previously thought possible. A pilot plant with enrichment columns of 1 m diameter and 3 m height, constructed at Hyuga City in Miyazaki Prefecture, demonstrated the recovery of 3% enriched uranium in April 1988. Subsequent development work has brought further advances in process economy and continuous-operation performance.