[3J06-09] External/DynamicPRA

[3J06] Improvement of Evaluation Method for Flooding Propagation for Internal Flooding PRA

*Daichi Nagai¹, Koji Tasaka¹, Koji Shirai¹ (1. CRIEPI)

Keywords:Internal flooding PRA, Flooding propagation, Non-watertight door, One-hour rating fireproof door, Fragility

To conduct the internal flooding PRA, flooding propagation through the non-watertight doors should be evaluated. Currently, there are few studies regarding fragility of non-watertight doors. The conventional method for evaluating flooding propagation assumes that the water level where the door opens is about 0.3 m. However, the generality of this assumption is unclear, and its applicability needs to be confirmed. In this study, we evaluated the fragility of the doors used in the Japanese NPPs. The results showed that the fragility of the door was about 1.3 m, which deviated from the conventional standard (about 0.3 m). Moreover, we have tested an method based on the test, and found that it is expected to improve the accuracy of the method.