气冷微堆燃料设计的中子学特性影响研究

为分析气冷微堆燃料设计的中子学特性影响，基于方形燃料组件模型，利用蒙特卡罗程序RMC研究了TRISO颗粒、燃料芯块在燃料设计中的主要参量对组件中子学特性的影响。研究结果表明，燃料颗粒体积占比和包覆层厚度不变时，组件寿期随燃料核芯直径的增大先显著增大，而后趋于平稳；燃料颗粒体积占比和燃料核芯直径不变时，组件寿期随包覆层厚度的增大而减小；燃料装载量不变时，芯块直径增大，组件寿期显著增大，而芯块高度影响较小；无燃料区厚度的增加对组件中子学特性有明显的负面影响，基体材料密度、基体杂质硼当量对组件中子学特性的影响较小。研究结果将为后续气冷微堆包覆颗粒弥散燃料的设计优化提供指导。

Research on Influence of Neutronics Characteristics in Fuel Design of Micro Gas-cooled Reactor

To analyze the neutronics characteristics in the fuel design of micro gas-cooled reactor, the influence of main parameters of TRISO particle and fuel pellet on the neutronics characteristics of the square fuel assembly model was investigated using Monte Carlo program RMC. The results show that the lifetime increases with the kernel diameter smartly at the beginning and then becomes smooth gradually when the TRISO particle packing fraction and coating layer thicknesses are invariable, and decreases with the increase of the coating thickness when the volume fraction of fuel particles and the diameter of fuel core are invariable. The lifetime is influenced by the coating layer thicknesses slightly, and will be longer as the fuel pellet diameter bigger when the uranium loading is invariable. While the no-fuel zone thickness has a remarkable negative impact on the neutronics characteristics, and the matrix density and the matrix impurity boron equivalents have a weaker impact. These results will instruct the follow-up design and optimization of coated particle dispersion fuel for the micro gas-cooled reactor in the future.