Qualification of advanced LEU fuels for high-power research reactor conversion designs

The two running EURATOM-funded projects EU-QUALIFY and EU-CONVERSION, coordinated by the HERACLES consortium, are developing and further qualifying advanced LEU fuel systems for conversion purposes of high-power research reactors (HPRRs). Three fuel systems have been identified as potential candidates to replace the use of highly-enriched uranium fuel, namely the uranium silicide dispersion fuel (U 3 Si 2 /Al), the U-10Mo monolithic fuel and the dispersed U-7Mo/Al fuel system. The U-Mo monolithic and the U 3 Si 2 /Al dispersion fuel systems are currently being advanced in technology readiness level, towards more representative generic test assemblies, mimicking more closely target reactor specific conditions. A number of irradiation experiments have so far been conducted on the two dispersion fuel systems and the first monolithic irradiation experiment at the Belgian BR2 reactor is targeted to commence during 2025. The post-irradiation examinations of the historical and ongoing tests will be concluded within the projects and the complementary HERACLES work programme. These projects are also important contributors in establishing industrial-level fabrication processes of high-loaded and high-density uranium silicide fuels as well as U-Mo monolithic fuels. The operational times of the current HPRRs are foreseen to be extended by their conversions and, thus, have an essential impact on the future European supply of reactor-produced medical radioisotopes.