Optimization of VVER-1200 Reactor Core Design: Enhancing Power Homogeneity and Safety

摘要: This study aimed to identify the optimal VVER-1200 reactor core model through computational burnup analysis to achieve homogeneous power distribution and improved neutronic as well as safety parameters by varying assembly orientations. Eight core models each based on differently enriched fuel assemblies with varying numbers of integrated burnable absorber rods were evaluated based on key parameters such as effective multiplication factor (keff), radial core power distribution, peaking factor (PPF), conversion ratio, and effective delayed neutron fraction, using the burnup calculation code SERPENT-2.1.32 and the ENDF/B-VII.1 nuclear data library. Model 6 showed the best performance, maintaining a keff close to 1.0 over 360 Effective Full Power Days (EFPD), with a balanced conversion ratio and the lowest PPF. A three-batch refueling scheme with a cycle length of 360 EFPD ensured sustained power generation and operational criticality. Negative fuel temperature coefficient (FTC) and moderator temperature coefficient (MTC) values across all cycles highlight inherent safety mechanisms.