【摘要】 在钍钚燃料热管冷却微型核反应堆堆芯中，功率分布不均匀性是一个关键问题。为优化堆芯功率分布，本研究选取具有较好中子学性能的BeO、Be、Graphite、MgO、Al₂O₃等反射层材料，分析比较了这些材料对堆芯功率分布及其他物理特性的影响。结果表明，采用MgO作为反射层材料可以有效改善堆芯的轴向和径向功率分布，并降低结构质量；同时MgO的使用软化了中子能谱，提高了堆芯初始反应性，确保堆芯寿期满足5 a需求。单通道模型热工分析表明，采用MgO材料堆芯的底部温度得到明显改善，尽管钍钚燃料的热导率较UO₂燃料低，导致堆芯整体轴向温度略高，然而钍钚燃料在热管冷却微型反应堆堆芯中的运行温度始终低于其熔点，满足了热工安全的要求。本研究可为钍钚燃料在热管冷却微型核反应堆中的应用提供设计参考和理论支持。更多还原

【Abstract】 Power distribution inhomogeneity is a key issue in thorium-plutonium fueled heat pipe cooled micro nuclear reactor. In order to optimize the power distribution in the core, the reflector materials such as BeO, Be, Graphite, MgO and Al₂O₃, which have better neutronics properties, are selected in this study, and the effects of these materials on the power distribution and other physical properties of the core are analyzed and compared. The results show that the use of MgO as the reflector material can effectively improve the axial and radial power distribution of the core and reduce the structural mass; at the same time, the use of MgO softens the neutron energy spectrum, improves the initial reactivity of the core, and ensures a 5-year core lifetime. Thermal analysis based on single channel model shows that the bottom temperature of the core is significantly improved with the MgO material, although the thorium-plutonium fuel has a lower thermal conductivity than the UO₂ fuel, resulting in a slightly higher overall axial temperature.However, the thorium-plutonium fuel operates consistently below its melting point in the heat pipe cooled microreactor core, thereby meeting the thermal safety requirements. This study can provide design references and theoretical support for the application of thorium-plutonium fuel in heat pipe cooled micro nuclear reactor.更多还原