Quantitative assessment of severe accident management strategies in a nuclear power plant

Nuclear power plants in Korea are preparing improvement countermeasures for severe accidents including mobile gas turbine generators, passive autocatalytic recombiners, containment-filtered venting systems, and external injection using portable pumps. However, these improvement countermeasures have only been determined by expert judgment, and detailed validation of their effects has not been performed. In this paper, the quantitative safety impact of these improvement countermeasures was evaluated for the Westinghouse 3-loop pressurized water reactor. Our evaluation of four improvement countermeasures using the at-power internal event probabilistic safety assessment models revealed that all containment failure modes have positive effects, except for the containment isolation failure and the containment bypass. Therefore, post-Fukushima action plans for coping with a severe accident in Korea have been appropriately evaluated and established.