Study of Kinetic and Neutronic Parameters for HEU and Potential LEU/MEU Fuels in a Typical MNSR

The MTR-PC package, which combines WIMSD and CITATION codes, was used to calculate the effective delayed neutron fraction and prompt neutron lifetime for a Miniature Neutron Source Reactor (MNSR). In the Reduced Enrichment for Research and Training Reactors (RERTR) program, these kinetic parameters were calculated for various potential LEU and MEU fuels. The effect of composition changes due to fuel depletion on these parameters was studied for HEU and potential LEU/MEU fuels. The results of kinetic and other neutronic parameters for the HEU MNSR core are in agreement with the values in the literature. The delayed neutron fraction and prompt neutron lifetime showed minor variations over the 200 Effective Full Power Days (EFPD) burnup cycle of the MNSR cores for each fuel. The maximum change in delayed neutron fraction (βeff) over the burnup cycle was found for UO2 fuel with Zircaloy-4 clad system, showing the maximum 239Pu production among all fuel types. The maximum neutron generation time (Λ) increase of 0.4µs was found in UAl4 90.3% enriched core.