The Denatured Thorium Cycle—An Overview

We performed a scenario evaluation that delineates the potential role of denatured uranium/ thorium-fueled reactors, including breeders, in symbiotic systems. In this study, reactors fueled with plutonium were built in secure centers, while reactors at dispersed sites were fueled with natural, lowenriched, or denatured uranium (12% 233U or 20% 235U in 238 U)The installed nuclear capacity is assumed to be 350 MW(electric) in the year 2000, with a net increase of 15 GW(electric)/yr permitted through the year 2050. The U.S. Department of Energy Division of Uranium Resources and Enrichment projected the two bounding cases of uranium recoverable at a marginal cost of $160/lb U3O8 or less used in this study. The marginal cost of $160/lb U3O8 occurs at 3 million short tons (ST) for the high-cost supply and at 6 million ST for the intermediate-cost supply.For the assumed high-cost U3O8 supply (3 million ST U3O8), thermal recycle with denatured light water reactors (LWRs) will achieve the same incremental increase in maximum achievable nuclear capacity as U/Pu recycle in LWRs [~200 GW(electric) more than once-through cycles]. Introduction of a breeder is required for the system to achieve the projected nuclear demand [1100 GW(electric) in 2049]. For all denatured systems, including those with breeders, a significantly larger fraction of the installed capacity can be located at dispersed sites, compared with U/Pu systems.For the assumed intermediate-cost U3O8 supply (6 million ST U3O8), thermal recycle with advanced converters will permit projected nuclear demand to be met for both the Pu/U and denatured uranium-thorium cycles.