This is a summary report by the Hydrogen Mitigation Experiments for Reactor Safety (HYMERES) project on the PANDA and MISTRA experiments.
Phase 1 of the Project, between 2013 and 2016, focused on improving the physical understanding of hydrogen release, transport and mixing in nuclear reactor containments and studying suppression pressure pool system issues with the goal of enhancing the modelling capabilities in support of safety assessments that will be performed for current and new nuclear power plants.
Hydrogen is an important concern because deflagration and even detonation can occur, which might result in a damage of the containment with a possible release of radioactive material into the environment. Thus it is crucial to know 1) how the hydrogen mixes with air and steam, 2) if this mixing would lead to a uniform distribution of hydrogen or, in contrast, 3) if the hydrogen would accumulate in specific regions.
The present project summary report was prepared in order to provide the international research community with an overview of the main outcomes of Phase 1 of the project.