Characteristics of Hydrogen Distribution under Steam Condensation in an Enclosed Vessel: Steady-State and Transient Tests

Although hydrogen has been recognized as a promising material for global energy transportation, its inadvertent leakage or generation into enclosed spaces may pose a risk of an explosion hazard in engineering facilities, including nuclear power plants. To manage the associated risks, it is crucial to identify the characteristics of hydrogen dispersion in air and its stratification behavior. In this study, we conducted an experimental investigation on the distribution of hydrogen in an enclosed vessel under steam-condensing conditions by using helium as a substitute for hydrogen. A series of steady-state and transient tests were carried out in a cylindrical test vessel, in which the interacting effect with steam condensation was simulated by employing a vertical condenser tube to promote the mixing of the steam-air-helium mixture. During transient tests, the impact of the jet momentum created by helium injection into the enclosure and subsequent buoyancy-driven redistribution of helium in the postinjection phase was observed.