Analysis of Shock Wave and Containment Behavior Under Severe Accident Internal Hydrogen Explosion Based on CEL Method

Abstract

Experience from the Fukushima nuclear accident has shown that the complex reactions caused by the melting of the core in a severe accident can generate large amounts of hydrogen and possibly lead to an explosion. At present, most of the newly built pressurized water reactors with large containment vessels use hydrogen ignition devices or hydrogen recombiners to avoid large-scale hydrogen explosions in reactor building. However, the change of the lower limit of hydrogen explosion caused by the high temperature and high pressure environment in the containment during the accident, and the characteristics that hydrogen is easy to accumulate in the higher dome or local room, make the occurrence of local hydrogen explosion still possible. In this paper, the CEL method is used to simulate the internal explosion test reported in the literature. The numerical value of overpressure and the characteristics of the constrained explosion features are in good agreement with the reported data. Determine the conditions under which the containment dome space is filled with hydrogen at the upper explosive limit. The TNT equivalent mass was calculated using the equivalent method. Then the containment model was established. The internal explosion under the constrained condition of the containment was calculated, and the characteristics of the shock wave and the behavior of the containment were analyzed.