Initial irradiation testing of very high density, low enriched uranium (LEU) fuels based on uranium–molybdenum dispersions beginning in the late 1990˙s established the promising irradiation behaviour of these fuels. Subsequent experiments in different countries found shortcomings in fuel behaviour at high power and temperature. These negative developments considerably delayed the international effort led by the ´reduced enrichment for research and test reactorsˇ (RERTR) programme to develop and qualify these fuels. At present, as a consequence of extensive cooperative research, several potential remedies are available to correct the fuel performance problems; these range from relatively minor changes to the fuel and matrix chemistry, to replacement of the aluminium matrix with another material, or to eliminate the matrix altogether. All of these variations are currently being investigated as part of a fuel development international collaboration with IAEA participation. At the back end of the fuel cycle, hundreds of research reactors worldwide, both operational and shut down but not yet decommissioned, are storing spent fuel on site. In many cases, this research reactor spent nuclear fuel (RRSNF) is old (more than 30 years) and physically degraded. Therefore the continued safe, reliable and economic handling, management and storage of RRSNF of all types, standard, failed and experimental, is a serious issue for almost all Member States with research reactors. In particular, most RRSNF is aluminium clad and in wet storage with less than optimum water chemistry and is particularly vulnerable to corrosion. Many Member States, especially those having research reactors but no power reactors, are expressing concerns about final disposition of research reactor spent nuclear fuel. Non-proliferation and environmental concerns have become just as important, if not more so, as the above mentioned technical concerns.
This task is designed to address these issues. It also responds to recommendations of the IAEA conference on ´Research Reactor Utilization, Safety, Decommissioning, Fuel and Waste Managementˇ and the annual international RERTR meetings since 2004. In line with the recommendations of the last two mentioned conferences, attention is also put on core and target conversion from HEU to LEU and the minimization of the use of HEU in research reactors and other facilities.