Application of similarity analysis method in neutronics design of multi-purpose experimental reactor

In response to the demands of new types of reactors and digital reactor development, as well as software validation, the core neutronics design of multi-purpose experimental reactors with high flexibility and broad applicability are conducted. This aims to enhance the critical physics experimental efficiency of new types of nuclear energy systems. To ensure the high credibility of experimental results, it is imperative to establish a high degree of similarity between multi-purpose experimental reactor cores and target reactor cores. Introducing similarity evaluation indexes based on energy spectrum, sensitivity, and uncertainty, a similarity analysis code is developed and validated through comparison with the similarity analysis code TSUNAMI-IP in the SCALE code system, yielding relative deviations in similarity calculations all below 1%. Design schemes for core loading in multi-purpose experimental reactors are explored, proposing driver core and experimental core design scheme. The experimental core can be flexibly adjusted according to different target cores to accommodate various fuel assembly types, such as plate, annular, and rod configurations, as well as diverse experimental requirements for fast and thermal spectrum. Utilizing the developed similarity analysis code, the similarities between the experimental core and target cores in different loading schemes are analyzed. Furthermore, optimization designs for loading schemes are conducted to reduce the number of experimental core assemblies while satisfying similarity conditions, thereby enhancing core economics. The realization of the design goal of one reactor for multiple purposes with flexible adjustments reduces the development cycle and costs of experimental reactors, thereby improving their utilization efficiency. This research holds significant implications for the development of multi-purpose experimental reactors and new types of nuclear energy systems.