NEA Rig-of-safety Assessment (ROSA-2) Project

The NEA ROSA-2 project aimed 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 focused 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. Generated a system-integral and sa eparate-effect experimental database to validate predictive capability and accuracy of computer codes and models. Thermal-hydraulic phenomena coupled with multi-dimensional flows that might have included mixing, stratification, counter-current flows, parallel-channel flows and oscillatory flows were the main focus of the investigations.

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

The experimental program was intended to provide a valuable and broadly usable database to achieve the above cited objectives. The NEA ROSA-2 Project consisted of six LSTF experiments that mainly included 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 have been directed to a different target following a discussion with the project partners. The NEA ROSA-2 Project ran from 01 April 2009 to 31 March 2013.

Project participants

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

Related links

Last reviewed: 23 October 2013