A review is made of the ongoing lines of R&D in the field on Nuclear Fission and potential alternatives based on specific features of some types of reactors. This nuclear perspective is confronted with a proposal on sustainability criteria for the Nuclear Fission field. This proposal stems from an analysis of the main drawbacks of Nuclear Fission, notably those related to security, safety and environment. On the other hand, it is pointed out that Nuclear Fission is a sound and proven CO2-free source of energy, with an outstanding maturity in its current stage of commercial development, and with an enormous potential to undergo new phases of industrial developments by exploiting very appealing features of the nuclear phenomenology, which deserve further research, under the guidance of sustainability concepts and criteria. (C) 2009 Elsevier Ltd. All rights reserved.