OverviewIn the European Commission 5th and 6th Framework Programme, a number of significant projects have been launched, aimed at investigating innovative strategies for increased efficiency, economy and sustainability and for safe and optimised radioactive waste management. In fact, during FP6, projects were initiated to study advanced systems, as defined in the framework of the Generation-IV: VHTR, GFR, LFR, SFR, SCWR and MSR: most of these innovative systems (and in particular those based on fast neutron spectra) allow the deployment of optimised waste minimisation technologies, compatible with sustainability and increased proliferation resistance goals. Moreover, P&T strategies based on the use of Accelerator Driven Systems are being addressed within the integrated project EUROTRANS. All the above mentioned nuclear systems are considered as well within the Sustainable Nuclear Energy Technology Platform (SNE-TP) with the objective to define roadmaps for their development in Europe.
Although significant differences exist among the different reactor concepts under consideration and despite the fact that at present no definitive design has been established for any of them, the operating conditions envisaged for those systems are quite demanding and they will impact the performance of the structural materials. In fact, for the declared objectives to increase efficiency and enhance economy, high operating temperatures and high burn-ups are important goals from the process engineering point of view. However, the safety and the feasibility of most of these nuclear reactor concepts and their optimisation will depend crucially on the capability of the chosen structural materials to withstand the expected operating conditions (in presence of one of the different coolants presently under investigation) and under specific thermal-hydraulics conditions. Therefore, well targeted research activities are required both to qualify the existing materials under the extreme conditions typical of the innovative systems and to develop and qualify new materials and coatings, for longer term perspectives.