Losing containment at high temperature and pressure—an experimental study with water-steam circuit

The design of pressure vessels aiming to contain water under high pressure and temperature conditions considers steady state behavior of the fluid. But if pressure decreases suddenly thanks to a leak or a rupture, water can get into a supercritical state. Supercritical state is a high energy and metastable state that could lead to a catastrophic accident such as explosion. The phase change of the superheated fluid is expected to entail a violent repressurization of the vessel, and may blow up the vessel. Little data can be found in literature about that repressurization process. The aim of this work was there to measure the repressurization dynamics of superheated water following a loss of containment. Experiments were performed at high temperature and pressure (up to 315 degrees C, 100 bar) in order to understand the phenomenon. The pressure drop in the tank was fast and well below the saturation pressure at the given temperature. Then, a repressurization peak occurred, depending on the pressure drop history. The set of results is discussed and compared to literature data.