While the optimal use of the energy potential of uranium calls for development of the fast breeder reactor, it appears that their introduction could take more time than anticipated a few years ago. During this interim period, the recycle of the plutonium in thermal reactors is considered by several users as an interesting provisional alternative. In western Europe, 20 to 30 tons of irradiated mixed oxide (MOX) fuel exist today and between 100 and 300 tons could have been unloaded by about 1995, depending on the reprocessing capabilities for standard light water reactor (LWR) fuel and the implementation program for fast breeder reactors. The main differences between standard and MOX fuels result from the composition of the core material; however, these differences do not cause major technical difficulties that cannot be solved by established or known means. The reopening of the former Eurochemic plant at Mol, Belgium, for the reprocessing of nonstandard fuels, among which plutonium fuel unloaded from LWRs could occupy a leading position, would offer an opportunity to demonstrate the feasibility of this type of reprocessing and simultaneously cover the needs of the European countries adopting the recycle of plutonium in thermal reactors.