IRPhE Technical Review Group

The International Reactor Physics Experiment Evaluation (IRPhE) Project provides the nuclear community with qualified benchmark data sets by collecting reactor physics experimental data from nuclear facilities worldwide. More specifically, the objectives of the expert group are as follows:

  • maintaining an inventory of the experiments that have been carried out and documented;
  • archiving the primary documents and data released in computer-readable form;
  • promoting the use of the format and methods developed and to seek to have them adopted as a standard.

Experiments where interest and priority are expressed by member countries or working parties and executive groups within the NEA to provide guidance or co-ordination in:

  • compiling experiments into a standard international agreed format;
  • verifying the data to the best extent possible by reviewing original and subsequently revised documentation, and by consulting with the individuals who are familiar with the experimenters or the experimental facility;
  • analysing and interpreting the experiments with current state-of-the-art methods;
  • publishing the benchmark evaluations electronically.

The Expert Group:

The secretariat of the group is provided by the NEA Data Bank, in charge of the management of the material released to the project. The IRPhE Technical Review Group is chaired and co-ordinated by John D. Bess from Idaho National Laboratory (INL), United States.

Current activities

The group currently:

  • maintains an international inventory of relevant reactor physics experiments and measurements, preserving the primary documentation and data describing the facilities in computer-readable form, characterising the experimental techniques, the experimental results and interpretation;
  • develops and maintains an international database containing a sub-set of high-priority reactor physics benchmark specifications derived from the experiments performed at various nuclear facilities around the world, relevant for or including data from power reactors (e.g. advanced gas reactors, fast reactors, Generation IV reactors, water reactors, etc.).

The following type of measurements are included:

  • fundamental mode lattice experiments;
  • heterogeneous core configurations;
  • power reactor start-up data;
  • core follow experiments;
  • specific applications experiments (e.g. fission product integral data, irradiation experiments).

The benchmark specifications and experimental data are intended for use by nuclear reactor physicists and engineers to validate current and new calculational schemes. It includes computer codes and nuclear data libraries for assessing uncertainties, confidence bounds and safety margins, and to record measurement methods and techniques.

2021 edition and availability

For more information about the 2021 edition, please visit the following page


IRPhE co-operates with the International Criticality Safety Benchmark Evaluation Project (ICSBEP).


Much of the work realised so far by the International Reactor Physics Experiment Evaluation (IRPhE) Project, in particular, the evaluation and review of selected benchmark experiments, was possible thanks to substantial funding provided by the Government of Japan. Argentina, Belgium, Brazil, Canada, China, Czechia, France, Germany, Hungary, Italy, Japan, Korea, Russia, Serbia, Slovenia, South Africa, Sweden, Switzerland, United Kingdom, and the United States have contributed evaluations, reviews and data at their own expense. Overall technical coordination of the IRPhE Project is directly supported by the United States Department of Energy's Office of Nuclear Energy with significant in-kind contributions from the NEA International Criticality Safety Benchmark Evaluation Project (ICSBEP), supported in the United States by the Department of Energy's Office of Facility Management and ES&H Support.