在核电厂反应堆压力容器（RPV）的辐照脆化监督试验中，会采用易于装卡的直通型紧凑拉伸断裂韧性C（T）试样，进行测试时会将引伸计装卡在试样端面进行变形的测量。测量到变形数据后，再通过特定推算方法将数据转换为加载线位移，而目前并未形成统一的推算方法。为了验证不同推算方法的有效性，采用有限元技术分析了C（T）试样的变形规律。结果表明：针对核电站RPV材料，GB/T 21143-2014中给出的端面变形测量与加载线位移的转换方法与有限元结果最为符合，该推算方法的精度最高。

In irradiation surveillance tests of reactor pressure vessel (RPV) in nuclear power plants, easy-to-use straight through compact tensile fracture toughness C(T) specimens are used, and the strain is measured by mounting an extensometer on the front face of the specimen when testing. After the strain data is measured, the data is converted to load-line displacement by a specific inferring method. At present, there is no unified calculation method. In order to verify the validity of the different inferring methods, the deformation law of C(T) specimens was analyzed by finite element. The results show that the conversion method of front face deformation measurement and load-line displacement given in GB/T 21143-2014 was most consistent with the finite element results for the RPV material of nuclear power plant, and the accuracy of this inferring method was the highest.