CRITERION-BASED METHOD FOR QUALIFYING THE STRATEGY OF INCREASING THE NOMINAL POWER OF NUCLEAR REACTORS

In the materials of the article, examples the analysis of known approaches to the substantiation (qualification) of strategies for operating VVER/PWR nuclear reactors at increased nominal power levels is presented. It has been established that the main shortcomings of the existing approaches to qualifying upgrades of the nuclear reactor core lie in the dependence of qualification results on the implementation methods of the reactor operation strategy in high nominal power modes, as well as on the effects of differences in deterministic codes and/or user expertise with such codes. These factors ultimately complicate the objective interpretation of qualification results. A criterion-based method for qualifying the strategy for operating nuclear reactors at increased nominal power levels has been developed. This method is based on upgrading the thermophysical properties of nuclear fuel and the design and technical parameters of fuel element components. It eliminates the influence of variations in deterministic codes and/or user expertise with such codes and considers safety assurance conditions under the maximum allowable temperatures for fuel cladding and nuclear fuel.