Influence of a shock absorber presence in the simulation of an explosion

When a molten metal contacts a cold volatile liquid, the energy transfer may cause a very quick vaporization of the cold liquid. This phenomenon is generally called vapour explosion. Vapour explosions have also been studied in the nuclear industry for the past thirty years as a possible cause of radioactive release in the unlikely event of extensive core melting during a severe accident. The accident is generally supposed to be caused by the partial melt down of the core of the nuclear reactor. If the corium spreads in presence of water, the energy release during the interaction is likely to cause a vapour explosion.. As a consequence, the short and high induced over-pressurization can challenge the integrity of the surrounding structures. We are considering a possible process to recover and cool corium in case of a nuclear accident. The corium is supposed to spread on a plate covered by a water layer whose role consists in cooling and solidifying the liquid corium. In some cases, a possible steam explosion can happen and the compartment surrounding the cooling process must be able to resist this kind of explosion. The aim of these computations consists in representing a very energetic explosion and to test the efficiency of the presence of a shock absorber to protect the bottom of the compartment from the over-pressurization. The geometric model is described and then the results of the simulations are analysed and compared. (author)