Effect of the burnable absorber on the efficiency of nuclear fuel cycle in VVER-1200 reactor

Abstract

The significant impacts of burnable absorbers (UO2+Gd2O3) on reactivity, neutron multiplication factor (Keff), burnup, neutron flux distribution, power peaking factor, as well as safety criterions of the VVER-1200 reactor are discussed in this paper. Fuel economics have improved, resulting in increased enrichment of fuel & the need for better neutron flux distribution as well as reactivity controls. In order to achieve these enhancements in neutron flux distribution, burnable absorbers must be incorporated into the fuel matrix. To compute the 3D (three-dimensional) model for VVER-1200 fuel assembly, the Monte Carlo Serpent code was used. There are different processes for loading 8.0% Gd2O3 as integral burnable absorbers (IBAs) on the VVER-1200 assembly. In the first fuel cycle, the calculations were carried out under normal operating conditions. The fuel assemblies of VVER-1200 reactor with (Gd2O3) and without gadolinium oxide (Gd2O3) are compared in terms of neutron multiplication factor (Keff) and neutron flux distribution in this research. The inclusion of gadolinium oxide significantly improves reactor safety by greatly flattening the neutron flow and so reducing power peaks, especially at the reactor core. Finding their impacts on the behavior of the reactor core is therefore an important factor in each reactor core plan, construction and safely functioning. The inclusion of gadolinium oxide (Gd2O3) significantly improves reactor safety by greatly flattening the neutron flux and reducing power peaks, particularly near the center of the core. The analysis of the current work is crucial for improving the reactor core design, arrangement of fuel rod, fabrication of fuel pallet, placement of control rod and the safety of reactor operation.