Abstract: Returning the regenerated uranium reprocessed from spent nuclear fuel to the fuel cycle is of great significance to the sustainable development of nuclear energy. Based on the Q model cascade, analysis was carried out on a separation scheme of producing low enriched uranium (LEU) from regenerated uranium in the aspects of the scale of separation cascade, material recovery, consumption of natural uranium, etc. The results show that, to produce the same amount of LEU, the less natural uranium is consumed, the higher the material recovery, the larger the closed fuel cycle index of spent fuel, but the larger the scale of the separation cascade. The economy of producing LEU from regenerated uranium should be considered, combining the factors such as natural uranium consumption, cascade scale, and closed fuel cycle index. The results also demonstrate that this scheme is able to satisfy the requirement for the complete closed fuel cycle, is simple but yet quite satisfactory, and can be an option in practical application.