The ordinary Weibull distribution function has been commonly accepted for empirical characterization of cleavage fracture toughness of nuclear reactor and containment pressure vessel steels. However, this method lacks a fundamental basis. This work adopts the standardized Weibull distribution function to analyze cleavage fracture toughness of ferritic steels measured from different sized fracture mechanics specimens at different temperatures to estimate the Weibull modulus. The toughness data of five different nuclear reactor and containment vessel steels are analyzed. The estimations obtained the Weibull modulus (m) in the range of 1.83 to 2.55 and strong temperature dependence of the threshold cleavage fracture toughness K_min, as opposed to the constant values of m_K = 4 and K_min = 20 MPam^1/2 given in ASTM E1921-19. The goodness of fit test by the one-sample Kolmogorov–Smirnov (K–S) test validated Weibull distribution function for describing the toughness distribution.

对于核反应堆和安全壳压力容器钢的劈裂断裂韧性的经验表征，通常接受普通的威布尔分布函数。但是，这种方法缺乏基础。这项工作采用标准化的威布尔分布函数来分析从不同尺寸的断裂力学试样在不同温度下测得的铁素体钢的劈裂断裂韧性，以估算威布尔模量。分析了五种不同的核反应堆和安全壳容器钢的韧性数据。估计获得的威布尔模量（m）在1.83至2.55的范围内，并且阈值解理断裂韧性K _min与温度的强烈相关性（与m _K的恒定值相反）ASTM E1921-19中给出的= 4和K _min = 20 MPam ^1/2。一次抽样的Kolmogorov–Smirnov（KS）测试的拟合优度验证了描述韧性分布的Weibull分布函数。