Study on First Cycle Loading of PWR Nuclear Power Plant Based on Multi-reactor Management

The core loading pattern is one of the most crucial design components for the effectiveness and safety of a power plant. As new fuel assemblies are used for whole core in the traditional first cycle loading pattern, many discharged assemblies from the first cycle will unavoidably be abandoned, resulting in insufficient fuel and core economy. Therefore, it is imperative to conduct research on approach for the first cycle loading design with improved fuel economy and more rational fuel assembly utilization. In this paper, a design method for the first cycle loading of PWR nuclear power plant based on multi-reactor management is proposed. By sharing the fuel assemblies of multiple units, the first cycle of multiple units is designed as multi-reactor, so as to improve the enrichment of new fuel assemblies used in the first cycle and meet the cycle length requirements. Reducing the number of new fuel assemblies on the basis of ensuring the cycle length of each unit can significantly improve the fuel utilization rate and the burnup of the first cycle unloading assembly, realizing a significant increase in the unit's economy. A representative HPR1000 reactor is used for verification. The results demonstrate that 41 new fuel assemblies can be reduced in two units with the same cycle length under the multi-reactor mode, and all the core parameters are within the design limits. This study can provide reference for the first cycle loading design of subsequent units to enhance the economy and competitiveness of nuclear energy.