In this area, research takes place using both simulation techniques and very effective experimental facilities. Simulation has become so important in research programmes that there are now whole teams working to produce the next generation of computing tools.
Digital simulation of complex systems uses both theoretical and physical models supported by experiment and calculations intended to explore the range of the possible by scientific means, to help in decision-making and to act as an engineering tool for design and optimisation. This powerful tool, based on developments in computing, is used to produce a precise temporal and three-dimensional description of complex systems and developmental changes. The approaches adopted are multi-scale (from atom to matter, through to the production of useful articles) and multi-physics (mechanical, physical, thermal, hydraulic and physicochemical combined).
In practical terms this research aims to improve the performance of current nuclear power plants, in terms of: Fuel efficiency, particularly during planned changes in the reactor power, ptimisation of fuel consumption, life of materials and the operating term of the power plants. It also focuses on the design and selection of future generations of reactors, in terms of longterm development.
For long-term stock-piling or storage of radioactive waste in geological strata, simulation techniques can model all the natural events that could possibly contribute to the dispersion of the radioactivity outside the confinement material, through its containers and into the natural environment. This takes into account changes in their physical-chemical properties and transfer mechanisms by diffusion or exchange with underground watercourses.
The Saclay centre has a remarkably varied and highquality choice of experimental facilities available to carry out this research.
Considerable test resources are devoted to mechanical and thermo-mechanical investigations, as well as to thermo-hydraulics of mono- and two-phase (steamvapour) events.
The Tamaris installation, housing the largest vibrating table in Europe, is used to test the resistance of materials and large structures to earthquakes. There is a wide range of analytical methods available for the isotopic and physico-chemical characterisation of materials.
Corrosion and the degradation of physical and mechanical properties likely to affect materials over time under actual conditions of use, including irradiation, can also be studied. For this, we have at our disposal the Osiris research reactor which has been specially designed for irradiating materials, complemented by “hot” laboratories, fitted with remote manipulators, for physical, chemical and metallurgy studies, as well as mechanical tests, on irradiated materials.
These investigations are performed together with CEA’s partners, including EDF, Framatome, COGEMA, ANDRA and the IRSN, and for European and international collaborative projects.