Multiscale and multiphysics applications of thermal-hydraulics

Sub-Project 3 Multiscale and multiphysics applications of thermal-hydraulics aims at developing accidental thermal-hydraulics expertise by improving and validating simulation tools for modelling four situation targets relevant to safety analysis of light water reactors: LOCA, PTS and BWR thermal-hydraulics including pressure suppression pool behaviour.


This work package aims at developing and validating advanced tools and methods for a multiscale and multiphysics analysis and simulation of LOCAs and other system TH transients belonging to the Design Basis Accidents. Such transients are currently treated by System TH codes such as CATHARE-2 and ATHLET. The addition of two-phase CFD tools and of advanced fuel models allows to revisiting these transients for more accurate and reliable predictions. This may require coupling of CFD with system codes, coupling of fuel thermo-mechanics with thermal-hydraulic codes and new methods for evaluation of accuracy, sensitivity and uncertainty of coupled simulation tools.


PTS is a main safety issue related to the life extension of present LWRs. The objective here is to demonstrate that an ECCS injection will not induce a brittle failure of the reactor pressure vessel, which would result in a severe accident.

This work package aims at finalising the simulation process of two-phase PTS scenarios engaged in NURISP by using a multiscale analysis of the phenomena, including validation and with a first approach towards the evaluation of uncertainty for CFD tools.

The investigation of models in CFD codes will focus on analysis of experimental data, especially the steam-water TOPFLOW experiment carried out by HZDR (Germany) or KAERI tests. The intended improvements are relative to:

  • Free surface modeling including the Large Interface Modeling (LIM)
  • Steam condensation modeling
  • Turbulence mixing

Several modeling approaches will be used and compared, including RANS, VLEIS and LEIS.

BWR applications

This work-package comprises two situation targets:

One is the investigation of dry-out mechanism and modelling using CFD codes, based on local parameters. The developed models will be validated and implemented in platform CFD codes.

The second situation is the modelling of the pressure suppression pool. This task uses some experimental data obtained in the PPOOLEX experimental programme for the validation of new models for direct contact condensation. The validation of the CFD models will use the very large validation matrix which was identified in the NURESIM project and the most recent experiments such as the BFBT data and the PPOLEX data.

< Multiscale analysis of core thermal-hydraulics from DNS to subchannel modellingPlatform>

SAVE THE DATE: 4-5 Nov 2015!
*Programme updated on 3 Nov

The NURESAFE Final seminar will be held on 4-5 November 2015 in Brussels, following the EUROSAFE Forum 2015 on 2-3 November 2015. The event will be open to the scientific community and other EU projects.

Registration & final programme available here >

November 2014:
Learn more on the NURESIM software (updated flyer)

October 2014:
Download the NURESAFE Newsletter Edition #1

16-17 June 2014:
NURESAFE General Seminar 2014 in Budapest:
Access all presentations here

April 2013:
Register for URANIE and SALOME training sessions (Closed)

28-30 Jan 2013:
NURESAFE kick-off meetings

1 Jan 2013:
Launch of the NURESAFE project

31 Dec 2012:
End of the FP7 NURISP project