²³⁵U enrichment by pulse gas diffusion

Abstract

LIGHT-WATER nuclear reactors use uranium fuel enriched in isotope ²³⁵U. One of the enrichment processes is gaseous diffusion. This process is used in large-scale plants in the US and uses the fact that, in the Knudsen diffusion condition, ²³⁵UF₆ diffuses through the porous membrane at slightly higher rate than ²³⁸UF₆. A transient Knudsen diffusion process is proposed here which gives a higher enrichment factor for the lighter species compared with a steady state diffusion process. Because of the higher enrichment, the number of stages required for enriching ²³⁵U to a concentration level suitable for nuclear power reactor fuel is considerably reduced.