目的 研究大型乏燃料运输容器用球墨铸铁材料的断裂韧性，进而给出工程应用中评价断裂韧性的建议。方法 通过对顶部和套料试样进行断裂韧性测试，获得不同位置试样的断裂韧性数据。分别采用双参数威布尔分布和正态分布进行统计分析，验证2种分布方法在断裂韧性测试中的适用性，分析大断面球墨铸铁低温断裂韧性对材料参数预期指标的满足情况。结果 大型乏燃料运输容器用球墨铸铁材料断裂韧性数据满足威布尔分布及正态分布的要求，国产容器的断裂韧性均远高于各国际标准。结论 完成了首次国产大型乏燃料运输容器用球墨铸铁筒体铸件材料低温断裂韧性分析评价，系统地掌握了断裂韧性情况，为容器结构设计、材料选择、失效模式分析和缺陷评定提供了依据。

The work aims to study the fracture toughness of ductile cast iron for large-scale spent fuel transportation casks to give recommendations for evaluating fracture toughness in engineering applications. The fracture toughness data of specimens at different locations were obtained by conducting fracture toughness tests on top and nesting specimens. The two-parameter Weibull distribution and normal distribution were used for statistical analysis, respectively, to verify the applicability of the two distribution methods in the fracture toughness test, and to determine the satisfaction of the requirement parameters for low-temperature fracture toughness of ductile iron with large cross section. The fracture toughness data of ductile iron materials used in large-scale spent fuel transportation casks meet the requirements of Weibull distribution and normal distribution, and the fracture toughness of domestic containers was much higher than the international standards. The fracture toughness analysis and evaluation at ultimate service temperature have been completed and the fracture toughness has been systematically grasped, providing a basis for the structural design of vessels, material selection, failure mode analysis and defect assessment.