Progress in the development OF LEU fuel

New nuclear fuels are being developed to enable many of the most important research and test reactors worldwide to convert from high enriched uranium (HEU) fuels to low enriched uranium (LEU) fuels without significant loss in performance. The development work is an international effort lead by the US RERTR program under the NNSA's GTRI. Initial testing (circa 2003) demonstrated that the unexpected tendency of U-Mo fuels dispersed in aluminum toward unstable swelling (pillowing) under high-power conditions. Technical investigations were initiated worldwide at this time by the partners (including Argentina, Canada, France, South Korea and Russia) understand this behaviour as well as to develop and test remedies. This paper gives an overview of the current status of U-Mo fuel development, including basic research results, manufacturing aspects, and the results of the latest irradiations and post irradiation examinations. (authors)