(a) Schematic of the obtained probability distribution. Here, the probability distribution of embrittlement under varying neutron fluence is provided as an example; the corresponding probability distribution of the embrittlement with other variables can be obtained by specifying the arbitrary values for the other factors. (b) The lower standard deviation of the residuals of the calculated and measured values corresponds to better predictability; thus, the accuracy of embrittlement prediction was improved. (c) Using the proposed method confirmed the accuracy of the embrittlement prediction margin established by the current Japanese code.