In the high-temperature gas-cooled reactors (HTGRs), nuclear graphite has been widely applied as the reflector, moderator, structural material and TRISO-containing matrix material. In this paper, we focused on the primary knock-on atoms (PKA) produced in nuclear graphite by Monte Carlo simulations. An effective HTGR model was performed and simulated by MCNP code to evaluate the neutron distribution and recoil distributions. The results were then used in SRIM code to calculate and compare the primary displacement damage, where Kinchin-Pease, Full-Cascades and Norgett-Robinson-Torrens methods were applied with different neutron recoil cascade input and ion incidence cascade input. In addition, simulations on PKA induced by hydrogen, helium, carbon, argon, xenon, gold ions were performed, for considering the extensive use of ion irradiation as a surrogate for neutron irradiation. It was found that ion implantation produced PKAs with lower average energy than neutron irradiation. In addition, from the point of view on the energetic spectra and spatial distribution of the primary damage, Xe⁺ irradiation with an incident energy of 1 MeV exhibits similar characteristics as neutron implantation.

在高温气冷堆（HTGR）中，核石墨已被广泛用作反射器，减速剂，结构材料和含TRISO的基质材料。在本文中，我们重点介绍了通过蒙特卡洛模拟在核石墨中产生的主连锁原子（PKA）。进行了有效的HTGR模型，并通过MCNP代码进行了仿真，以评估中子分布和后坐力分布。然后将结果用于SRIM代码中，以计算和比较一次位移损伤，其中Kinchin-Pease，Full-Cascades和Norgett-Robinson-Torrens方法应用于不同的中子反冲级联输入和离子入射级联输入。此外，还对氢，氦，碳，氩，氙，金离子诱导的PKA进行了模拟，考虑广泛使用离子辐照作为中子辐照的替代物。发现离子注入产生的PKA的平均能量低于中子辐照。另外，从高能谱和主要损伤的空间分布的角度来看，Xe入射能量为1 MeV的⁺辐照具有与中子注入相似的特性。