Multiphysics applications involving core physics

The overall objective of SP1 multiphysics applications involving core physics is to develop transient simulations for Pressurised Water Reactors(PWR) including Water-Water Energetic Reactors (VVER), and Boiling Water reactors (BWR) using multiphysics coupling capabilities, which have in the most part been developed during NURISP.

Three situation targets that require coupling between different disciplines have been selected: PWR and VVER Main Steam Line Break (MSLB)and BWR Anticipated Transient Without Scram (ATWS).


The goal is to perform best-estimate analysis for a PWR main steam-line break scenario using coupled NURESIM codes, supplemented by uncertainty evaluation for thermalhydraulics, and thermo-mechanical parameters. The key features of the application to be developed are an improved representation of the core regions with strong concentration gradients an accurate concentration and temperature distribution from CFD modeling and a systematic uncertainty evaluation.

By modeling the MSLB transient in this way, this work will generate reference results at the cutting–edge of current analysis technology and will provide more accurate assessment of margins between key parameters and safety criteria.


Similarly to PWR, the objective is a best-estimate analysis for a BWR ATWS scenario using coupled NURESIM codes, supplemented by uncertainty evaluation for TH and thermo-mechanical parameters. In order to generate reference results at the forefront of current analysis technology, the analysis framework featuring coupled simulations will combine:

  • System thermal-hydraulics
  • 3D neutronics
  • Thermo-mechanic evaluation of fuel safety parameters
  • Uncertainty evaluation

< NURISP ProjectMultiscale analysis of core thermal-hydraulics from DNS to subchannel modeling>