Restoration of the isotopic composition of reprocessed uranium hexafluoride using cascade with additional product

Abstract

In reprocessed uranium, derived from an impoverished fuel of light-water moderated reactors, there are isotopes of 232, 234, 236U, which make its recycling remarkably difficult. A method of concentration of 235U target isotope in cascade's additional product was proposed to recover the isotopic composition of reprocessed uranium. A general calculation procedure is presented and a parameters' optimization of multi-flow cascades with additional products. For the first time a numeric model of a cascade that uses the cuts of partial flows of stages with relatively high separation factors was applied in this procedure. A novel computing experiment is carried out on separation of reprocessed uranium hexafluoride with providing a high concentration of 235U in cascade's additional product with subsequent dilution. The parameters of cascades' stages are determined so as to allow reducing the 232, 234, 236U isotope content up to the acceptable. It was demonstrated that the dilution of selected products by the natural waste makes it possible to receive a low enriched uranium hexafluoride that meets the ASTM C996-15 specification for commercial grade.

Keywords

• Reprocessed uranium
• Separation isotopes
• Multi-flow cascade