Multi-objective Optimization of a Heat Pipe-Cooled Reactor Coupled with He-Xe Brayton Cycle System

The micro heat pipe reactor combined with a helium-xenon (He-Xe) Brayton cycle power system offers high reliability and efficiency, making it a promising candidate for advanced nuclear power applications. Based on an established He-Xe regenerative closed Brayton cycle model, this study combines thermodynamic analysis with a one-dimensional regenerator design method to improve overall system performance. Under specified heat pipe and cooling loop temperature conditions, the temperatures and pressure drops of individual components are calculated iteratively to examine the effects of pressure ratio, heat pipe temperature, and cooling loop temperature on cycle efficiency and specific power. A multi-objective optimization based on the Non-dominated Sorting Genetic Algorithm II (NSGA-II) is conducted, with the cycle thermal efficiency and specific power as the optimization objectives, and the pressure ratio, heat pipe temperature, and cooling loop temperature defined as the decision variables, where the resulting Pareto frontiers clearly demonstrate the inherent trade-offs between these competing objectives. Additionally, the optimization investigates the influence of microchannel diameter variations in the regenerator on the overall system performance. The results demonstrate that variations in the heat pipe and cooling loop temperatures have a significant impact on the system’s cycle efficiency and specific power. According to the LINMAP decision method, the optimal operating conditions differ among recuperator channel diameters, yielding efficiencies of 44.93%, 45.99%, and 45.57%, with corresponding specific powers of 76,357, 74,746, and 78,436 W/kg for diameters of 0.5, 0.8, and 1.0 mm, respectively.