National audience The Fukushima accident is based on the question of the social and economic viability of nuclear technology. In response to this, we analyse the process of internalising the external costs of nuclear power, which is reflected in the continuous complexity of technology and has the peculiarity of being outraged by major accidents. It has contributed to disrupting the process of learning technology and questioning social preferences and finally questioning its competitiveness for investors. Independent security institutions have become a condition for its deployment, at the risk of not facilitating the stabilisation of the technology, which is a condition for its economic viability. In this perspective, the article shows that the new sequence of internalisation of the external costs of nuclear power opened by Fukushima will have limited cost effects as a result of the earlier stages of safety deepening. The complexity of the technology reaches an asymmptotic: we are emerging from the challenge of learning through accidents. On the other hand, maximum safety must be ensured by tackling the other root of the problem: that of the independence and powers of the safety authorities in all countries, which is not a term of office. However, it is at this price that this global public good, which is the acceptance of nuclear power, will be preserved.