Besides the European Global Energy Policy, the European Council adopted an action plan that covers nuclear technologies and supports research in order to "further improve nuclear safety and the management of radioactive waste". To obtain a more efficient and sustainable management of radioactive waste and hence reduce the burden on geological storage, one can apply partitioning and transmutation independently of future commitment or not to nuclear energy. Within European Union many R&D organisations and industries are conducting since a decade strong R&D in the Partitioning &Transmutation (P&T) field with substantial support from the European Commission. Fostering the European efforts towards a major facility realisation would be very beneficial. This will speed up the development and put Europe at lead in this field. The design of a fast spectrum transmutation experimental facility (FASTEF), able to demonstrate efficient transmutation and associated technology through a system working in subcritical mode (ADS) and/or critical mode, is thus the next step after FP6 IP-EUROTRANS. In the vision report of the "Sustainable Nuclear Energy Technological Platform", the need was clearly expressed for a fast-spectrum experimental system to support the development and demonstration of an alternative technology to sodium. Therefore, FASTEF is proposed to be designed to an advanced level for decision to embark for its construction at the horizon of 2012 with the following objectives: to demonstrate the ADS technology and the efficient transmutation of high level waste; to operate as a flexible irradiation facility; to contribute to the demonstration of the Lead Fast Reactor technology without jeopardising the above objectives.