Bimodal Space Nuclear Reactors (BSNRs) are designed to operate in two different kinds of modes, which are respectively high-power propulsion mode for movement in outer space and low-power power mode for supplying power to space vehicle-mounted systems. As BSNRs can take full use of nuclear energy generated by reactors, they are of huge potential to be applied in future space missions and thus attract much attention of researchers around the world. In this paper, a new conceptual design of Heat Pipe Cooled Bimodal Space Nuclear Reactor (HP-BSNR) was proposed. In order to evaluate the feasibility and safety of the proposed conceptual design, preliminary neutronics and thermal-hydraulics analysis for HP-BSNR were performed. For neutronics analysis, MCNP4B (Monte Carlo Natural Particle Transport Code) has been adopted to calculate the effective multiplication factor k_eff and neutron flux distribution. For thermal-hydraulics analysis, mathematical models such as propellant thermodynamics, propellant-fuel element heat transfer, fuel heat conduction, energy distribution and so on have been established. Then, a thermal-hydraulics analysis code named TTHA_HPBSNR (Transient Thermal-hydraulics Analysis for Heat Pipe Cooled Bimodal Space Nuclear Reactor) was developed and validated by program ELM together with experimental data from the published literature. With the self-developed code, steady state and typical transient accidents of HP-BSNR including reactivity insertion accident and partial loss of flow accident were simulated. The preliminary analysis results indicate that the proposed conceptual design of Bimodal Space Nuclear Reactor with Heat Pipe (HP-BSNR) is feasible in terms of neutronics and thermal-hydraulics analysis.

双峰空间核反应堆（BSNR）设计为两种不同的运行模式，分别是在外层空间运动的高功率推进模式和为空间车载系统供电的低功率模式。由于BSNRs可以充分利用反应堆产生的核能，它们在未来的太空任务中具有巨大的应用潜力，因此受到世界各国研究人员的广泛关注。在本文中，提出了一种新的热管冷却双峰空间核反应堆（HP-BSNR）概念设计。为了评估拟议概念设计的可行性和安全性，对 HP-BSNR 进行了初步的中子学和热工水力分析。对于中子学分析，_效果和中子通量分布。对于热工水力分析，建立了推进剂热力学、推进剂-燃料元件传热、燃料热传导、能量分布等数学模型。然后，开发了一个名为 TTHA_HPBSNR（热管冷却双峰空间核反应堆的瞬态热工水力分析）的热工水力分析代码，并通过程序 ELM 以及来自已发表文献的实验数据进行了验证。使用自行开发的程序，对HP-BSNR稳态和典型瞬态事故进行了模拟，包括反应性插入事故和部分失流事故。