Feasibility analysis of Uranium-Based fission fragment magnetic collimation space propulsion system

Abstract

The theoretical specific impulse of the direct fission fragment propulsion system exceeds 10⁶ s, making it more appropriate for long space exploration compared to existing nuclear propulsion methods. Previous studies on fission fragment propulsion systems have been limited to employing Am-242 m as fuel, lacking investigations on system reactivity control and fuel temperature distribution. This study suggested a direct fission fragment propulsion system using U-235 as fuel. Firstly, the neutronics features of the system were investigated using the Monte Carlo software RMC. Subsequently, Fluent was used to compute the temperature distribution of the fuel assembly. MATLAB was then applied to analyze the temporal variation of the system’s propulsion properties. Finally, “navigation cost” was defined to compare the performance of different propulsion methods. Computation results revealed that the uranium-based fission fragment propulsion system exhibits good critical and safety features. The initial k_eff of the system is 1.015, the specific impulse reaches 5.88 × 10⁴ s, and the fuel element temperature is below 1000 K. Additionally, the navigation cost of the fission fragment propulsion system is lowered by 2 to 6 orders of magnitude compared to other propulsion technologies. This study validates the theoretical viability of the uranium-based fission fragment propulsion system and demonstrates its significant advantages for long-distance deep space exploration missions, providing an alternate option for deep space exploration.