The main objectives of INPRO are to: help ensure that nuclear energy is available to contribute towards fulfilling energy needs in the 21st century in a sustainable manner; and bring together both technology holders and technology users to consider jointly the international and national actions required to achieve desired innovations in nuclear reactors and fuel cycles. Within INPRO the future energy demand and supply was explored and several scenarios were identified. The following requirement for energy supply will play a crucial role: sustainability of the way the energy supply will be realized. Fulfilling the growing need for energy in developing countries is also an important issue. On the basis of scenarios for the next fifty years, requirements for the different aspects of the future of nuclear energy systems, such as those on economics, environment, safety, waste, proliferation resistance and infrastructure, have been identified as well as a methodology developed to assess innovative nuclear systems and fuel cycles. On the basis of this assessment, the need for innovations in existing nuclear technology, to be achieved via research, development and demonstration, can be defined. To facilitate the deployment of innovative nuclear systems, different aspects of the infrastructure, technical as well as institutional, also have been reviewed, and recommendations for changes are made to anticipate the main developments worldwide, such as ongoing globalization.