For traditional spent fuel shielding materials, due to physical and chemical defects and cost constraints, they have been unable to meet the needs. Therefore, this paper carries out the first discussion on the application and performance of bismuth in neutron shielding by establishing Monte Carlo simulation on the neutron flux model of shielded spent fuel. Firstly, functional fillers such as bismuth oxide, lead oxide, boron oxide, gadolinium oxide and tungsten oxide are added to the matrices to compare the shielding rates of aluminum alloy matrix and silicone rubber matrix. The shielding rate of silicone rubber mixture is higher than aluminum alloy mixture, reaching more than 56%. The optimal addition proportion of bismuth oxide and lead oxide is 30%, and the neutron radiation protection efficiency reaches 60%. Then, the mass attenuation coefficients of bismuth oxide, lead oxide, boron oxide, gadolinium oxide and tungsten oxide in silicone rubber matrix are simulated with the change of functional fillers proportion and neutron energy. This simulation result shows that the mixture with functional fillers has good shielding performance for low energy neutrons, but poor shielding effect for high energy neutrons. Finally, in order to further evaluate the possibility of replacing lead oxide with bismuth oxide as shielding material, the half-value layers and various properties of bismuth oxide and lead oxide are compared. The results show that the shielding properties of bismuth oxide and lead oxide are basically the same, and the mechanical properties, heat resistance, radiation resistance and environmental protection of bismuth oxide are better than that of lead oxide. Therefore, in the case of neutron source strengths in the range of 0.01–6 MeV and secondary gamma rays produced below 2.5 MeV, bismuth can replace lead in neutron shielding applications.

中文翻译：

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基于蒙特卡罗模拟的氧化铋乏燃料干式储存容器屏蔽性能研究

对于传统的乏燃料屏蔽材料来说，由于物理化学缺陷以及成本限制，已经无法满足需求。因此，本文通过建立屏蔽乏燃料中子通量模型的蒙特卡罗模拟，对铋在中子屏蔽中的应用和性能进行了首次探讨。首先，在基体中添加氧化铋、氧化铅、氧化硼、氧化钆、氧化钨等功能性填料，比较铝合金基体和硅橡胶基体的屏蔽率。硅橡胶混合物的屏蔽率高于铝合金混合物，达到56%以上。氧化铋和氧化铅的最佳添加比例为30%，中子辐射防护效率达到60%。然后，模拟了硅橡胶基体中氧化铋、氧化铅、氧化硼、氧化钆和氧化钨的质量衰减系数随功能填料比例和中子能量的变化。模拟结果表明，功能填料混合物对低能中子具有良好的屏蔽性能，但对高能中子屏蔽效果较差。最后，为了进一步评估氧化铋替代氧化铅作为屏蔽材料的可能性，对氧化铋和氧化铅的半值层和各种性能进行了比较。结果表明，氧化铋和氧化铅的屏蔽性能基本相同，且氧化铋的机械性能、耐热性、耐辐射性和环保性均优于氧化铅。因此，当中子源强度在0.01-6 MeV范围内且产生的二次伽马射线低于2.5 MeV时，铋可以在中子屏蔽应用中替代铅。