[1N01-07] PRA Method

[1N04] Importance Measure Considering Common Cause Failure

Proposal of Combination Importance

*Ryoto Kobayashi¹, Yasuki Ohtori¹, Hitoshi Muta¹, Masato NAKAJIMA² (1. TCU, 2. CRIEPI)

Keywords:Common Cause Failure, Importance Measure, Fussell Vesely, Risk Achievement Worth

To improve the safety of large and complex systems such as nuclear power plants, it is necessary to continuously identify and reinforce vulnerable areas. Traditionally, importance indices such as FV (Fussell-Vesely) and RAW (Risk Achievement Worth), which focus on a single component, have been used to identify vulnerable areas. However, when external events are targeted, it is necessary to assume common-cause failures and multi-hazard failures, so an index that can reflect the interaction effects of multiple devices is considered effective. In this infra-story, we propose a combined importance index for two components that takes into account the damage correlation of the entire system, and report the results of a study on the applicability of the index.