DETERMINING METHOD OF CONCENTRATION OF FUEL SUBSTANCE OF FUEL ROD AND DISTRIBUTION OF CONCENTRATION OF BURNABLE POISON

摘要

PURPOSE:To obtain a determining method of concentration of a fuel substance of a fuel rod and the distribution of concentration of burnable poison which can meet precisely the limitation to a maximum local output. CONSTITUTION:Neutron flux distribution in an observed bundle 10 is calculated by multi-bundle detailed computation wherein the environment of adjacent bundles 11 to 18 at least is simulated as the surrounding environment in the case when the observed bundle 10 is charged actually. Based on this neutron flux distribution, the distribution of local outputs of the observed bundle 10 is calculated, and based on this distribution of the local outputs, the enrichment (concentration of a fuel substance) of a fuel rod and gadolinia distribution (distribution of concentration of burnable poison) in the observed bundle 10 which meet the values of limitations to a maximum local output are determined.