It is of vital importance that all lessons from the first phase of nuclear power development are utilized in the planning of emerging nuclear systems. Nuclear power seems to have turned unacceptable in spite of its early promises. The prevailing view among experts is however that the public concerns are possible to approach with technological and institutional solutions. Before this view can be communicated to decision makers and the public it is necessary to learn the lessons from the twenty years of nuclear debate and from the TMI and Chernobyl accidents. The Chernobyl disaster brought the dangers of nuclear power concretely to common people. Increasing concerns for global warming is giving nuclear power a second chance to demonstrate its viability. In utilizing this second chance the industry should take due account of the arguments of the nuclear opposition. Social costs of an accident are very large and an accident anywhere will influence the whole industry. International cooperation is needed in assuring that all safety deficiencies are corrected. Coordinated approaches in informing the public are essential. The safety lessons should be integrated in evolutionary and revolutionary designs for new generations of power plants. The paper concludes with thoughts on how the problems of risk perception and social acceptance of nuclear power could be approached.