Conceptual design of megawatt-level mobile nuclear power system based on heat pipe cooled reactor

•The conceptual design of mobile nuclear power system named MNPS-1000 is proposed.•The physical and thermal characteristics of this modular nuclear reactor based on the high-temperature lithium heat pipes are obtained.•The energy conversion system combining the open-air Brayton cycle and a closed Rankine cycle is designed. Mobile nuclear power system has the advantages such as the well adaptability, the strong sustainability, and the convenient transportation, which can satisfy the energy demand of special environments such as island, and polar region. In this paper, the conceptual design of Mobile Nuclear Power System named MNPS-1000 is proposed, which is consist of the modular heat pipe cooled reactor and combined cycle energy conversion system to achieve the 1MWe output. The design characteristics include the operation lifetime of 3000 days in full power mode, negative temperature reactivity feedback, redundancy in reactivity control, 33% energy conversion efficiency. Due to the efficient heat transfer capability of lithium heat pipes, total of 216 heat pipes can ensure the heat transfer of 3MWt. The modular design of reactor and heat pipe heat exchanger decreases the volume of the system to achieve the compact arrangement in the standard containers with 12.0m×2.5m×2.5m size. The reactor physics and thermal hydraulics analysis, heat pipe design, and energy conversion system analysis are taken out to show the feasibility and performances of this conceptual design.