NEST Hydrogen containment experiments for reactor safety (HYMERES)

The NEST HYMERES (Hydrogen containment experiments for reactor safety) project, led by PSI (Switzerland) is addressing safety relevant phenomena in containments during accidents. It offers hands-on training opportunites during the experimental test campaigns carried out at the PSI PANDA facility, one of the most advanced containment test facilities worldwide.  In parallel, it also aims at developing exploratory research projects under the guidance of experts at Participating Organisations, in particular within the universities.



The OECD/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 OECD/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 OECD/NEA HYMERES-2 joint. project.


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 had the possibility to present the results of their activities in the HYMERES-2 project meetings and in seminars organized at PSI.

Leading organisation

  • Paul Scherrer Institute, Switzerland

Participating organisations

  • University of Stuttgart, Germany
  • Oregon State University, USA
  • Texas A&M University, USA
  • CNRS Orléans, France
  • Seoul National University, Korea
  • Swiss Federal Institute of Technology Zurich (ETH), Switzerland.
  • University of Calgary, Canada
  • Royal Institute of Technology (KTH), Sweden (non-NEST member)
  • Universidad Politécnica de Madrid, Spain (non-NEST member)



  • Stephen King, Texas A&M, USA
  • Lea Zimmerman, ETH, Switzerland
  • Kevin Manohar, University of Calgary, Canada
  • Carlos Vazques-Rodriguez, Universidad Politécnica de Madrid, Spain
  • Dmitry Grishchenko, KTH, Sweden


  • Michael Gorman,Texas A&M, USA
  • Denise Chavez, Texas A&M, USA
  • Brent Hollrah, Texas A&M, USA

The short presentation of the NEST Fellows can be found here.