External Reactor Vessel Cooling Strategy Application for APR1400 Station Blackout Scenarios

In Korea, all NPPs implemented post-Fukushima measures. In U. S., the approach is to expand B5b strategy to build up FLEX strategies utilizing portable equipment. With portable pumps and connections, one can mitigate and respond to wide range of accidents. In this study, we examined the feasibility of cavity flooding using portable pumps for ERVC and its effectiveness in responding to extended SBO scenarios. The external reactor vessel cooling (ERVC) is one of important severe accident management (SAM) strategies adopted for APR1400. ERVC strategy is to remove decay heat from molten corium in lower plenum by submerging the vessel with water. The strategy requires water injection into cavity and APR1400 uses shutdown cooling pumps for this purpose, requiring electricity. Recent Fukushima accident shows the importance of mitigation capability against extended SBO scenarios