other reactor options can be considered in part by comparison to that basecase. More detailed comparative assessments of the options based on criteria related to security, cost, and ES&H can be found in Chapter 6.
Light-water reactors (LWRs) are the most mature of any of the proposed burners of weapons plutonium (WPu). Over 100 LWRs are operating in the United States and about 400 worldwide. LWRs have over 4,000 reactor-years of operation. They supply almost 75 percent of the electricity consumed in France and about 22 percent of the electricity generated in the United States.
U.S. LWRs use low-enriched uranium (LEU) fuel. Plutonium in the discharged fuel is not reprocessed for recycle. In Sweden and the United States, geologic repositories are being designed primarily for long-term disposal of spent fuel discharged from uranium-fueled LWRs. Other countries are considering such a direct-disposal fuel cycle as well.
It is also possible to fuel LWRs with mixed-oxide (MOX) fuel, which combines plutonium dioxide and natural or depleted uranium dioxide as a PuO2-UO2 mixture. Work on such MOX fuels for LWRs has a long history. The U.S. Plutonium Utilization Program began in 1956, and was soon followed by related work in several European nations and Japan. The development effort was motivated in part by the potential for fuel-cycle economies perceived at the time and also as a means to reduce the consumption of uranium ore. It focused on the reprocessing of LWR discharge fuel to recover and recycle the plutonium and uranium. Several tests of partial core loadings of MOX fuel were conducted in U.S. LWRs during the 1960s and 1970s. Although plutonium recovered from LWR fuel was used in these tests, the results are generally applicable to MOX made from WPu.1
In 1963 Belgium used a partial loading of MOX fuel in its BR-3 pressurized-water reactor (PWR). After many years of experimentation, by 1986 Belgium irradiated a core with a 70-percent MOX loading. Belgium provides a significant fraction of the world's currently operating MOX fabrication capability and is considering an expansion of its MOX fabrication plant. Its MOX fabrication services are marketed in conjunction with France by the MELOX consortium. Two Belgian LWRs are licensed to burn MOX fuel.
Germany tested and demonstrated MOX fuel in LWRs from 1968-1977 and began commercial use of MOX fuel in LWRs in 1981. Seven reactors in
See Chapter 2 for a discussion of the differences between WPu and reactor plutonium (RPu). Details on the U.S. Plutonium Utilization Program are found in USNRC (1976).