5.16 - U-Mo Based Fuel System

Abstract for more than 2 decades a worldwide effort has been done to seek an acceptable solution for replacing the high enriched fuel still used in high performance research reactors. The U-Mo alloy system showed the most acceptable in-pile behavior in small-scale screening tests. Within Europe, the focus was set on the use of low enriched U(Mo) powder dispersed in an Al matrix as replacement. In the US another version of the fuel system was explored in which the UMo foil is rolled out into foils and subsequently clad with aluminum alloy cladding. This variant is referred to as monolithic fuel. This article introduces the particular properties and aspects of the UMo alloys, the fabrication process of UMo powder and foils, the plate fabrication process for monolithic and dispersion fuels and the currently available data on the in-pile behavior.