ICONE15-10038 ANALYSIS OF HYDROGEN COMBUSTION MITIGATION ACTIONS IN SEVERE ACCIDENT GUIDELINES OF A BOILING WATER REACTOR WITH MARK III CONTAINMENT

After the 1979 TMI-2 accident, the researches on the severe accidents of Nuclear Power Plants in the United States and other countries have made extensive progresses in both understanding the phenomena and developing the mitigation actions of the severe accidents. The U.S. Nuclear Regulatory Commission has indicated that the development of a plant specific accident management program is required to close the severe accident regulatory issue. In response to the policy, plant specific Severe Accident Guidelines (SAGs), which delineates the mitigation actions of core melt down accidents, is developed to support the operators and staffs in Technical Support Center (TSC) in dealing with those misfortunes. In SAGs of Boiling Water Reactor (BWR) with Mark III containment, specific mitigation actions are delineated to prevent the accumulation of hydrogen to a concentration that is high enough to threat the integrity of the containment. The mitigation actions include switch on igniters, and/or hydrogen recombiners, containment purge, and containment venting. The execution of these mitigation actions also has a potential of changing the course of accident progression. These impacts together with the effectiveness of these mitigation actions under different accident scenarios will be addressed in the paper based on the results of MAAP4 simulations. The surrogate plant analyzed is Kuosheng nuclear power plant of Taiwan Power Company. The plant employed a BWR VI reactor with Mark III containment. The rated thermal power of the plant is 2,894 MWth.