Evaluation of the Neutron Flux Distribution in Two-Zone Reactor – V. Kolykhanov, I. Kozlov, D. Polehenkyi, H. Kulyk

The distribution of heat release in the reactor core is important for reliable and safe operation of NPPs. During reactor campaign, the core composition changes due to fuel burnup and this leads to a change in the neutron flux distribution in the core volume. A numerical analysis of the change in the axial profile of the neutron flux in the reactor core, which divided into two parts symmetrical relative to the core centre, is presented. A one-group neutron diffusion model is used to find the axial profile of the neutron flux. Various combinations of the material buckling values of the two parts of core are considered. The relations between the materials buckling of the core parts that ensure the achievement of criticality are obtained. The marginal distributions of the neutron flux and picking factor are analysed.

Keywords: diffusion model, two-zone reactor, neutron flux, material buckling, criticality.