In-Core Flux Calculations Using MCNP6 for Core Aging Analysis

Abstract

The Pressure tube creep and sag due to core aging impact the operational life of CANDU® reactors. Pressure tube creep and sag are dependent on fast neutron flux, coolant temperature and time. The standard method for calculating fast neutron flux at the pressure tubes is based on WIMSAECL/RFSP calculations. A new method for calculating the fast neutron flux based on MCNP6 is presented. This provides accurate flux distributions throughout the core, which captures flux variations due to fuel bundle end regions, structural materials, and reactivity devices. The standard method is unable to capture any of these variations.