Abstract:
The multipurpose high flux research reactor MARIA is a water and beryllium moderated reactor of a pool type with graphite reflector and pressurised fuel channels. The main areas of reactor application is production of radioisotopes and physics research with usage of a neutron beam from horizontal channels. Conversion programme of MARIA research reactor is closely associated with the “Global Threat Reduction Initiative” (GTRI). The MARIA reactor is a Russian-designed research reactor that operates with Russian highly enriched uranium (HEU) fuel. The reactor initially was operated with 80% enriched HEU and converted to 36% HEU in 1999. The programme objective is to convert the current core to LEU fuel. The proposed silicide fuel (U3Si2) with a density of 4,8 g/cm3 has been qualified to achieving very high burnups. The assembly design proposed for use in the MARIA reactor will be unique, however, it needs to be qualified for the MARIA operating conditions by irradiating two lead test assemblies in the MARIA reactor. The main stage for LEU fuel qualification will be irradiation of the LTA’s in the MARIA core to the burn-up for qualification (~ 60%) is expected. The affirmative results of the post irradiation examination will allow for accomplishing the core conversion of the MARIA reactor by successive replacement of the fuel channels with high enrichment by the fuel channels with low enrichment.