Design and optimization of space nuclear power system with sCO2 Brayton cycle on Mars

As human exploration of outer space deepens, the demand for space power increases. This requires not only higher thermoelectric conversion efficiency but also a more compact system. Space nuclear power based on the sCO2 Brayton cycle is better suited for the surface of Mars due to its high efficiency and low ratio of mass to electric power. This paper designs a 6 MWt sCO2 Brayton cycle power generation system, and the following system configurations are mainly studied including Simple Heat Recovery Cycle (SRC), Re-Compress Heat Recovery Cycle (RC), Reheating Heat Recovery Cycle (RRC), and Reheating Re-Compress Cycle (RHRC). A thermodynamic calculation model of the system was developed based on the aforementioned cycle configurations. Additionally, a quality assessment model was developed separately for each component within the system, according to its respective category. The effects of parameters such as temperature, compressor pressure ratio, and bypass ratio on the system efficiency and total system mass are also examined for each of the four-cycle configurations. The study conducted a global multiparameter optimization using a genetic algorithm to optimize system efficiency and the ratio of mass to electric power. The RHRC configuration achieved the highest cycle efficiency at 39.47%, while the SRC cycle had the lowest system efficiency at 35.46%. The RRC configuration had the minimum ratio of mass to electric power at 7.419 kg/kWe with an efficiency of 33.13%.