The reuse of recycled uranium form the spent fuel can save the resource of natural uranium. The enrichment of 235U

dilution of 232U and compensation of burning-up depth caused by 236U must be synthetically considered in the separation of recycled uranium form LWR. Based on the cascade theory of multi-component isotope separation

several different cascade schemes for the separation of recycled uranium were presented. Theoretic calculations were conducted for different cascade schemes. The result of calculation shows that the double cascade scheme with a carrier gas is optimum one.