Development of External Flooding Hazard Assessment Methodology for Korea Nuclear Power Plants

Studies on the typhoon risk of Korea NPPs located in coastal regions have received little attention compared with other external events, despite recent strong typhoon landfalls near NPPs. Therefore a typhoon risk assessment is needed to establish a response system and predict the damage of NPPs from a typhoon. In this study, the external flooding hazard assessment method was proposed. In addition, the external flood height of KORI NPPs was calculated by using the method under 10-6 annual occurrence frequency. To develop the external flooding hazard assessment methodology a hydrodynamic analysis is conducted considering the storm surge and extreme rainfall condition and the flood height of KORI NPPs was calculated by using the developed method in this study. The protection system of flooding according to the scenarios can be established from the result of this study. The internal and external flooding factors are identified so that the flood risk can be analyzed at the nuclear plant site, In addition, the results of this study can be used as the reference to set up the structural and nonstructural flooding countermeasures.