European activities on cross-cutting nuclear thermal-hydraulics

For the long-term development of nuclear power, innovative nuclear systems such as Gen-IV reactors and transmutation systems need to be developed for meeting future energy challenges. Thermal-hydraulics is recognized as a key scientific subject in the development of innovative reactor systems. In Europe, a consortium is established consisting of more than 20 institutions of research centers, universities and nuclear industries with the main objectives to identify and to organize research activities on important crosscutting thermal-hydraulic issues encountered in various innovative nuclear systems. A large-scale integrated research project is proposed to FP7 of European Commission and expected to start in the near future.
The main topics considered in the THINS (Thermal-Hydraulics of Innovative Nuclear Systems) project are (a) Advanced reactor core thermal-hydraulics; (b) Single phase mixed convection; (c) Single phase turbulence; (d) Multiphase flow; (e) Numerical code coupling and qualification. The main objectives of the project are:

• Generation of a data base for the development and validation of new models and codes describing the selected crosscutting thermal-hydraulic phenomena. This data base contains both experimental data and data from direct numerical simulations (DNS).
• Development of new physical models and modelling approaches for more accurate description of the crosscutting thermal-hydraulic phenomena such as heat transfer and flow mixing, turbulent flow modelling for a wide range of Prandtl numbers, and modelling of flows under strong influence of buoyancy.
• Improvement of the numerical engineering tools and establishment of a numerical platform for the design analysis of the innovative nuclear systems. This platform contains numerical codes of various classes of spatial scales, i.e. system analysis, sub-channel analysis and CFD codes, their coupling and the guidelines for their applications.

The project will achieve optimum usage of available European resources in experimental facilities, numerical tools and expertise. It will establish a new common platform of research results and research infrastructure. The main outcomes of the project will be a synergized infrastructure for thermal-hydraulic research of innovative nuclear systems in Europe.
This paper summarizes some key crosscutting thermal-hydraulics issues and corresponding ongoing research activities in Europe. The technical and management structure of the THINS project will be described. Examples of results achieved so far will be presented.