A numerical neutronics benchmark study for inert matrix plutonium fuels inuranium dioxide and mixed plutonium-uranium dioxide environments

A numerical benchmark exercise has been under way for comparing the results of different calculational methods/data sets used for the analysis of ligh t water reactor (LWR) configurations employing Pu inert matrix fuels (IMFs) . The first phase of the exercise was devoted to infinite arrays of identic al IMF cells. The main feature investigated in the second phase has been th e influence of the neutron spectra in UO2 and MOX cores on individual IMF c ells. Phase 3 is concerned with the more realistic situation of an IMF asse mbly surrounded by UO2 assemblies. Significant discrepancies have been obse rved for power peaking effects and delayed neutron parameters in Phase 2. I n Phase 3, neutron balance differences for the IMF, particularly at EOL, ar e found to be significantly larger than were observed in Phase 1. (C) 2001 Published by Elsevier Science Ltd. All rights reserved.