Abstract
From the Fukushima accident, a natural disaster led to great damage to a nuclear power plant in no time was realized. It became clear more work was needed to address the plant ability to cope without sources of AC power which would otherwise be available to operate the engineered safety features. The overall objective of this research is to evaluate the Extended Loss of AC Power (ELAP) event to determine what actions can be taken to extend the coping capability of a Pressurized Water Reactor (PWR) during an ELAP condition and to alleviate those conditions which inhibit the ability to successfully survive such an event. This research studies the thermal-hydraulic phenomena of the plant during ELAP with and without mitigation strategies. The modeling and simulation works were done by using TRACE code. The applying of mitigation strategy during ELAP is to secure reactor core water coverage and fuel integrity as long as possible, and the results show that it can extend the time for core fuels to be uncovered for various hours in different situations. Furthermore, the duration gained by mitigation strategy is possibly for building up AC power sources and long-Term cooling system. This study can be used to help develop and incorporate emergency response guidelines, investigate areas of hardware improvement and procure portable equipment that could be used to help mitigate the ELAP event.