Effective use of uranium resources in light water reactor system

We have proposed an idea of recycling uranium recovered from spent fuels of light water reactors (LWRs), where the recovered uranium is to be re-enriched by a centrifuge cascade conventionally treating natural uranium. The idea is of making it possible to reuse the fuels reproduced in a multi-cycle of re-enrichment. The uranium recycle not only economizes on uranium resources but also gets rid of accumulation of spent fuel masses. In this work, we consider additional processes for effective use of uranium, which are of re-enriching the depleted uranium. The still-more-depleted uranium is advantageous as the matrix of MOX fuels used in LWRs for the purpose of surplus plutonium disposition, because a decrease of 235U in MOX fuel is made up by increasing a dose of plutonium. However, the depleted uranium derived from the cascade enriching the recovered uranium issues a little troublesome problem of 236U concerning its existence and deliveries to the product and the waste. We made a work to investigate the burn-up performance of these remade uranium fuels in model reactors of 1.1GWe-grade PWR and the mass balance in fuel recycles. The results suggest a strategy of effective use of uranium resources in the LWR system. (author)