ECLIPSE;A DIGITAL NEUTRON TRANSPORT PROGRAMME FOR TREATING THE NON-UNIFORM BURN-UP OF BURNABLE POISON PARTICLES INCORPORATED IN REACTOR FUEL

摘要

This report presents an outline of the physics and mathematics of a computer programme that calculates two-group neutron fluxes and associated burn-up of poison atoms within a spherical burnable poison particle.nThe problem consists, merely, in evaluating the neutron fluxes in three spherically concentric regions, the poison sphere being located at the centre of the system whereas the two surrounding regions may be, respectively, fuel and moderator or a carrier material and/or moderator.nSubsequently, a time-step is taken during which some of the poison and fuel atoms will be consumed and, eventually, formed whilst also the total neutron absorption rate by the particle is computed. During the time-step the neutron fluxes are assumed not to change.