A neutronics feasibility study for the LEU conversion of Poland's MARIA research reactor

The MARIA reactor is a high-flux multipurpose research reactor which is water-cooled and moderated with both beryllium and water. Standard HEU (80% 235 U) fuel assemblies consist of six concentric fuel tubes of a U-Al alloy clad in aluminium. Although the inventory of HEU (80%) fuel is nearly exhausted, a supply of high-loaded 36%-enriched fuel assemblies is available at the reactor site. Neutronic equilibrium studies have been made to determine the relative performance of fuels with enrichments of 80%, 36% and 1.97%. These studies indicate that LEU (19.7) densities of about 2.5 gU/cm3 are required to match the performance of the MARIA reactor with 80%-enriched and with 36%-enriched fuels, respectively. (author)