The lecture formed a commentary on the report of the Norwegian Government's Commission on Nuclear power Safety which was published in October 1978. It was introductorily pointed out that 'safe' and 'safety' are not in themselves meaningful terms and that the probability of an occurrence is the real measure. The main items in the Commission's report have been core meltdown, releases during reprocessing, waste disposal, plutonium diversion and environmental impacts. The 21 members of the Commission were unanimous in 7 of the 8 chapters. In chapter 2, 'Summary and Conclusions', 3 members dissented from the majority opinion, that, subject to certain conditions, nuclear power was a safe and acceptable source of energy.