New approach to beyond design basis events in structural strength field

Kasahara, Naoto*; Demachi, Kazuyuki*; Sato, Takuya*; Ichimiya, Masakazu*; Wakai, Takashi ; Yamano, Hidemasa  ; Nakamura, Izumi*

The conventional purpose in the field of structural strength has been to prevent damage to design basis events (DBE). For beyond design basis events (BDBE), it is necessary to mitigate the impact on safety on the premise that damage will occur. The authors propose a mitigation method that suppresses the consequence into a fracture mode with a large impact by reducing the load due to a fracture with a small impact on safety. We will introduce the research results for individual component, extend the applicable area to systems of components, and propose a new approach that contributes to improving plant safety.