Abstract
The relevance of this study is associated with the analysis of the reactor core of the EPR (European Pressurized Reactor) and the description of reactivity control mechanisms at all stages of the fuel cycle. The research considers both active (controllable) reactivity parameters such as control rod insertion depth and boric acid concentration, and passive parameters, including the burnup of burnable absorbers (gadolinium) and the accumulation of fission products. A comparative assessment of the parameters affecting reactivity has been performed. The results of the study confirm the high efficiency of the comprehensive reactivity control system in EPRs and demonstrate the necessity of an integrated approach to the analysis of the neutronic characteristics of the reactor core, taking into account both active and passive mechanisms of reactivity change.