Evaluation of multiple, self-recycling of reprocessed uranium in LWR

The multiple recycling of uranium in light-water reactors is evaluated to understand its sustainability in multiple recycling scenarios and to evaluate its impact on fuel design and the fuel cycle. Two recycling scenarios were evaluated. One involves the mixing of repU with natU prior to reenrichment. A second involves the mixing of repU with 19.9% EU to provide the new reactor fuel. The equilibrium concentrations of troublesome isotopes such as U-232 and U-236 are evaluated along with the required overenrichment of U-235. It was confirmed that a U-235 overenrichment factor of 0.28 applied to the U-236 concentration is sufficient to meet the cycle reactivity requirements and yields equilibrium enrichments of 5.06% and 5.52% for the two cycles, respectively. The impact on plutonium production and cycle reactivity is further evaluated to ensure the new fuel can meet the desired burnup requirements. Here, the plutonium production was found to be greater and the reactivity swing less in recycling scenarios with higher U-236 concentration.