The NEST HYMERES (Hydrogen Containment Experiments for Reactor Safety) project, spearheaded by the Paul Scherrer Institute (PSI) in Switzerland, focuses on studying safety-critical phenomena within containment structures during accidents. It provides hands-on training opportunities during experimental test campaigns conducted at the PSI PANDA facility, renowned as one of the most advanced containment test facilities globally. Simultaneously, the project aims to foster exploratory research initiatives under the mentorship of experts from participating organisations, with a particular emphasis on collaboration with universities.

Background

The NEA HYMERES-2 project is a major international project contributing to the extension of the experimental database on containment phenomena and on suppression pool issues.

The overall project scope is:

• to improve the physical understanding of hydrogen release, transport and mixing in nuclear reactor containments;
• to study suppression pool systems issues, with the goal to enhance modeling capabilities in support of safety assessments for current and new nuclear power plants;
• to create a suitable experimental database for the validation of advanced computational tools.

The PANDA series form four main categories or areas:

• Separate effects/ flow obstructions
• Safety components/systems
• Suppression pool phenomenology
• System/multi-compartment

The NEA joint projects such as HYMERES-2 benefit from a broad range of technical and scientific expertise in an international framework and are based on experimental and computational activities which have a potential to serve also as driving force for educational activities.

The NEST HYMERES project has been created as the educational component of the NEA HYMERES-2 joint project.

Objectives

Within the NEST HYMERES project experimental and computational research activities have been carried out by NEST Fellows. The objectives of the NEST Fellow activities are:

• to contribute with computational analyses to the definition of PANDA tests and to identify the optimal configurations to reach the objectives of the individual series;
• to gain insight into the computational modeling needs to represent containment phenomena in compartments or structures;
• to develop methodologies for processing the experimental data which could enhance the understanding of phenomena during specific tests;
• to perform complementary experiments in small and medium scale facility which could provide a broader understanding of the phenomena investigated in the HYMERES-2 project.

Moreover, the NEST Fellows have the possibility to present the results of their activities in the HYMERES-2 project meetings and in seminars organised at PSI.