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OECD/NEA Rig of Safety Assessment (ROSA-2) Project

The OECD/NEA ROSA-2 project aims to resolve key light water reactor (LWR) thermal-hydraulics safety issues highlighted from the first phase of the project, by using the ROSA/large-scale testing facility (LSTF) at the Japan Atomic Energy Agency.

In particular, the ROSA-2 Project will focus on the validation of simulation models and methods for the following complex phenomena of high-safety relevance for thermal-hydraulic transients in design basis events (DBE) and beyond-DBE:

  1. Generate system-integral and separate-effect experimental database to validate predictive capability and accuracy of computer codes and models. Thermal-hydraulic phenomena coupled with multi-dimensional flows that may include mixing, stratification, counter-current flows, parallel-channel flows and oscillatory flows will be the main focus of the investigations.

  2. Facilitate assessment of codes currently in use for thermal-hydraulic safety analyses as well as advanced codes presently under development including three-dimensional computational fluid dynamics (CFD) codes through active involvement of the project partners who will maintain and improve the technical competence in thermal-hydraulics for nuclear reactor safety (NRS) evaluations.


The experimental program is intended to provide a valuable and broadly usable database to achieve the above cited objectives. The OECD/NEA ROSA-2 Project consists of six LSTF experiments that mainly include two groups of experiments which are intermediate break loss-of-coolant (LOCA) accidents and steam generator tube rupture (SGTR) accidents. One of the six experiments may be directed to a different target following a discussion with the project partners. The OECD/NEA ROSA-2 Project is scheduled to run from 01 April 2009 to 31 March 2012.


Project participants

The project is supported by safety organisations, research laboratories and industry from the following countries: Belgium, the Czech Republic, Finland, France, Germany, Hungary, Japan, Republic of Korea, Spain, Sweden, Switzerland, the United Kingdom and the United States.


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NEA contact

Abdallah Amri (abdallah.amri@oecd.org)

Last reviewed: 10 November 2009