In the current context of growing energy needs and concerns for the environment, the development of abundant, affordable, and environmentally responsible energy technologies is considered as one of the main objectives for the coming decades. Nuclear power has the potential to meet future generations' energy needs in sustainable way and in long term scenarios; however, acceptance of nuclear energy as a large scale contributor to the world's energy mix depends on satisfaction of strict requirements in the areas of economy, safety, adequacy of natural resources, waste reduction, non-proliferation and public acceptance. One of the main public concerns related to the use of nuclear energy for electricity generation is the long term hazard of radioactive wastes arising from the nuclear fuel cycle. Light water reactor power plants, representing currently almost the totality of the fleet of nuclear power plants under operation worldwide, have been developed for fifty years and a high industrial maturity has been reached. However, LWR technology presents several disadvantages related to its fuel cycle characteristics. In particular, it allows only a poor exploitation of the energy potential of resources (natural uranium), generating problems and concerns related to their preservation and to the management of the radioactive waste. The world nuclear community is devoting efforts in the development of innovative technologies to make utilization of nuclear energy safer and more sustainable in terms of resource utilization and waste management. In order to achieve these objectives, innovative systems and advanced nuclear fuel cycle options are being studied and developed in various countries and at international level