No abstract available

[en] The conversion of uranium is the transformation of uranium concentrates into UO₂ or uranium metal or into UF₆ for subsequent enrichment. Evolution, market development, risks and new developments for uranium reprocessing and laser enrichment requiring metallic uranium are reviewed

[en] Although conversion is the least important step of the fuel cycle both natural U and reprocessed U have to go through it before further processing in the fuel cycle, such as enrichment or fuel fabrication. Reprocessed uranium from LWR is available today from the UP2 400 plant (Cogema-La Hague, France) and the pilot plant of WAK (DWK, FRG). New plants will be put on stream, in particular the UP3 plant (Cogema-La Hague, France) and the Japanese plant of Rokkasho-Mura. As of today almost all the reprocessed uranium from LWR fuels (1600 tons U) has been converted into UF6 by Comurhex in its unique in the world 350 tons U/year pilot plant, in line with the UP2-400 reprocessing plant at La Hague. For natural uranium conversion, there are five convertors with large capacities in the western world. Total conversion of natural uranium in 1986 has been well below 40,000 tons. Forecasts for the next 15 years show a slowly growing demand, to reach an average of 45,000 tons/year in the 1990s. There should be no problem for the present procedures to cope with the future market demand for the end of this century. Reprocessed uranium as uranyle nitrate or uranium oxide bears radioactive characteristics which require some added caution over natural uranium. The final step of conversion (i.e. fluorination from UF4 into UF6) has a powerful purification effect on reprocessed uranium, since most of the impurities are non-volatile fluorides and will be removed by in-line filters. (Nogami, K.)

[en] The conversion industry is reviewed against the background of supply (following an accident at a North American conversion facility in 1986), demand (which has increased) and future new markets (the conversion of reprocessed uranium and production of uranium metal to feed laser enrichment plants). The conversion process itself is explained. Conversion companies are discussed in terms of their capacities and orders. Uranium hexafluoride inventories and requirements are illustrated. Laser enrichment is a positive challenge to the conversion industry. (U.K.)

[en] Reprocessed uranium is potentially richer in energy than natural uranium. Following tests of reloading 4 PWRs with MOX fuel and reprocessed uranium into the Cruas-4-reactor, EDF decided in 1991 to proceed on an industrial scale: an oxide production unit with a capacity of 2000 metric tons U/year (Cogema) and a uranium fluoride(6) production unit (Comurhex) to be commissioned in 1994/5