On the problems of reusing reprocessed uranium by enrichment in schemes based on ordinary cascades

The problem of spent nuclear fuel attracts considerable attention while its quantity is accumulating worldwide. The problem of long-term supply of the fresh fuel also remains important. One of the strategies to solve both problems is reusing the spent nuclear material. The uranium, in this way, could be recycled multiple times in light-water reactors. In order to recycle the uranium, it is extracted from the irradiated fuel during the reprocessing and then enriched in 235 U, taking into account the limitations on reactor-born isotopes 232,236 U in the final product. The only way to do this is enrichment in cascades of gas centrifuges. However, not every cascade scheme is able to re-enrich the uranium for multiple recycles, utilizing the whole amount of uranium extracted from the irradiated fuel each time. This study shows that configurations based on ordinary three-flow cascades could not be used for this purpose. In particular, we have shown that starting from the second uranium fuel cycle, such schemes are no longer able to reclaim the necessary proportion of the reprocessed uranium.