A Comprehensive Approach to Elimination of Highly-Enriched-Uranium From All Nuclear-Reactor Fuel Cycles

Over a period of about a decade after President Eisenhower's "Atoms for Peace" speech, the U.S. and Soviet Union exported research reactors to about 40 countries. By the mid-1970s, most of these reactors were fueled with weapon-useable highly-enriched uranium (HEU), and most of those with weapon-grade uranium. In 1978, because of heightened concern about nuclear proliferation, both countries launched programs to develop low-enriched uranium (LEU) replacement fuel containing less than 20 percent 235U for foreign research reactors that they were supplying with HEU fuel. By the time the Soviet Union collapsed, most of the Soviet-supplied research reactors outside the USSR had been converted to 36% enriched uranium but the program then stalled because of lack of funding. By the end of 2003, the U.S. program had converted 31 reactors to LEU, including 11 within the U.S. If the development of very high density LEU fuel is successful, it appears that conversion of virtually all remaining research reactors with steady powers greater than 1 megawatt (MWt, thermal) could be completed by approximately 2012. It is also technically straightforward to convert to LEU the HEU targets used in the production of the fission product 99Mo, whose decay product 99Tc is widely used in medical procedures. However, there are political obstacles to ending the use of HEU in research and medical-isotope-production reactors. The big 99Mo producers are resisting conversion, and Russia has not yet committed to convert its own research reactors. Furthermore, large classes of reactors fueled with HEU including critical facilities, pulsed reactors, icebreaker propulsion reactors and naval reactors, have not yet been targeted for conversion. Most HEU-fueled reactors do not need to be converted, however. About a hundred underutilized HEU-fueled reactors should be shut down instead, and they and about another hundred already shutdown HEU-fueled reactors must be decommissioned. The fresh and spent HEU fuel at these reactor sites, as well as at the sites of reactors being converted, must be recovered and blended down to LEU. In 1996, the U.S. resumed taking back spent U.S.-supplied HEU fuel from foreign reactors. Recovery of fresh HEU fuel from foreign reactors supplied by the former Soviet Union began in 2002 with U.S. financial assistance, but return to Russia of spent exported Soviet and Russian HEU fuel is stalled. All these slow-moving programs must be consolidated and broadened into a comprehensive high-priority effort to eliminate HEU from all nuclear fuel cycles, including those of icebreaker, tritium-production and naval-propulsion reactors. Recently, there have been signs of increasing political support within the U.S. for a more comprehensive effort to help eliminate HEU from civilian nuclear fuel cycles worldwide. This article provides a preliminary map of the territory that would be covered by such a program.

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