[3J06-09] External/DynamicPRA

[3J08] Study on improvement of the efficiency of statistical sampling of rare event evaluation applicable for Multi-Unit Dynamic PRA using Continuous Markov process Monte Carlo method

*Tomomi Hanai¹, Satoshi Shinzaki¹, Takamasa Kurokawa¹, Kensuke Toyoshima¹, Masayuki Hijiya¹, Sunghyon Jang², Akira Yamaguchi² (1. NEL, 2. UTokyo)

Keywords:Dynamic PRA, Statistical Uncertainty, Continuous Markov Process, Rare Event, Monte Carlo Method

In dynamic PRA using the CMMC method, a major issue is a large number of trials required in Monte Carlo calculations to ensure reliability in the evaluation results of rare events with small probability of occurrence. In this study, we investigated a method to reproduce the results of a large number of trials using a Monte Carlo calculation with a small number of trials. Specifically, by increasing the branching ratio of the occurrence of an event in a Monte Carlo simulation trial and adjusting the confidence level of the trial according to the branching ratio, it is possible to reduce the statistical uncertainty in the evaluation results of rare events while ensuring the accuracy of the evaluation results. The proposed method is applied to dynamic PRA trial evaluation and the scope of its application is examined.