Feasibility and Safety Analysis of Solid-State Reactor for Lunar Surface Exploration

Abstract The Fission Surface Power System is a feasible solution for future lunar surface exploration energy supply, with the solid-state reactor being considered a primary candidate. This paper presents a modeling and analysis of a solid-state reactor based on publicly available information. Using the reactor Monte Carlo program RMC and the commercial finite element analysis software ANSYS, the reactor is modeled and analyzed. The power distribution of the active zone and reactivity feedback coefficients of the entire core are obtained. The result indicates a negative reactivity feedback coefficient, confirming this reactor design’s inherent safety. Furthermore, a two-dimensional reactor model is constructed to obtain the temperature distribution during full-power operation, and non-passive residual heat removal analysis and radiative heat loss failure analysis are performed. At the failure condition of all heat pipes, the maximum core temperature is 742 K, which is below the reactor safety temperature limit, confirming the residual heat removal capability of the solid-state reactor in the loss of heat sink. Additionally, the self-developed transient reactor system analysis program is used for thermal safety analysis. The thermal parameters and heat transfer limits of high-temperature alkali metal heat pipes within the reactor are obtained, with the ratio of heat transfer limit to the heat load of 2.05 demonstrating sufficient safety margins of the heat pipe operation in the reactor. The results manifest that the core is satisfied with the existing criteria for anticipated operating occurrences of solid-state reactors, verifying the excellent safety performance of this reactor design. Based on the analysis and calculations in this study, it is concluded that this reactor design exhibits superior safety performance, which is attributed to the neutron physics design concept of the intermediate neutron spectrum and the thermal-hydraulic design concept of non-passive residual heat removal. This study contributes to the field of advanced nuclear reactor engineering by providing a comprehensive analysis of the solid-state reactor design for the Fission Surface Power System. The findings highlight the superior safety performance and potential application of this solid-state reactor design for future lunar surface exploration, which has important implications for the development of lunar surface reactors.