In this chapter, we discuss the evolution of the field of ‘ethics of nuclear energy’, regarding its past, present and future. We will first review the history of this field in the previous four decades, focusing on new and emerging challenges of nuclear energy production and waste disposal, in light of several important developments. Four of the most pressing ethical challenges will be further reviewed in the chapter. First, what is a morally ‘acceptable’ nuclear energy production method, if we consider the existing and possible new technologies? Second, provided a new tendency to consider nuclear waste disposal with several countries, what would be the new ethical and governance challenges of these multinational collaborations? Third, how should we deal with the (safety) challenges of the new geographic distribution of nuclear energy, tilting towards emerging economies with less experience with nuclear technology? Fourth, nuclear energy projects engender highly emotional controversies. Neither ignoring the emotions of the public nor taking them as a reason to prohibit or restrict a technology – we call them technocratic populist pitfalls respectively – seem to be able to guide responsible policy making.