Conceptual design of heat pipe cooled reactor with liquid sodium core for space power systems

In recent years, small modular reactors, particularly heat pipe reactors, have garnered considerable interest owing to their miniaturization, modular design, and inherent safety characteristics. Extensive research efforts worldwide have yielded numerous conceptual designs. Meanwhile, space vehicles such as spacecraft and space stations demand reliable energy systems with stable power output, high efficiency, and long operational lifespans. Heat pipe reactors are well-suited for such applications. This study presents a conceptual design of heat pipe cooled reactor using in space environment, termed the Sodium ( Na )-based S pace T hermal- E lectrical R eactor (Na-STER). The system comprises five main modules: the reactor and shielding module, thermoelectric conversion module, energy transmission module, waste heat removal module, and auxiliary module. The reactor is designed to deliver an electrical output of 240.2 kW with an energy conversion efficiency of 20.02 %. Comprehensive neutronic and thermal analyses are conducted. Results show axial and radial power peaking factors of 1.33 and 1.37, respectively, indicating a relatively uniform core power distribution. The maximum core temperature reaches 1061.1 K under full-power conditions. Furthermore, the reactor's response to selected accident scenarios is assessed, demonstrating favorable inherent safety characteristics. This work provides valuable insights and design references for future nuclear power systems employing heat pipe reactor technology in space environments.