Expert Group on Uncertainty Analysis in Modelling (EGUAM)

The expert group provided advice to the Working Party on Scientific Issues of Reactor Systems (WPRS) on the scientific development needs (data and methods, validation experiments, scenario studies) of sensitivity and uncertainty methodology for modelling of different reactor systems and scenarios. It was completed in 2020 and its scope of work is currently addressed in the Working Party on Scientific Issues and Uncertainty Analysis of Reactor Systems (WPRS).

Publications and reports

The main activity was focused on uncertainties in modelling light-water reactor (LWR) transients. In this context the objectives were to:

  • determine modelling uncertainties for reactor systems under steady-state and transient conditions, quantifying the impact of uncertainties for each type of calculation in the multi-physics analysis, i.e.:
    • neutronics calculations
    • thermal-hydraulics modelling
    • fuel behaviour
  • determine for each of the above types of calculation the major sources of uncertainty arising from:
    • data (e.g. nuclear data, geometry, materials)
    • numerical methods
    • physical models
  • develop and test methods for combining the above sources of uncertainty for each type of calculation so as to yield uncertainty assessment for the coupled multi-physics analyses.
  • develop a benchmark framework which combined information from available integral facility and nuclear power plant experimental data with analytical and numerical benchmarking:
    • where available, experimental data was used to test the individual types of calculation as well coupled multi-physics simulations


EGUAM members' area (password protected | reminder)