Japanese group psychotherapists have already contributed a lot to support people in the painful work of overcoming the tremendous triple trauma created by the earthquake, the tsunami and the nuclear accident of March 2011. They have provided opportunities for people to combine individual recovery and collective mobilisation. We pay homage to the work they have done and are still doing. We would like to consider other contributions that group therapists and group processors could bring to this work by focusing specifically on the origin and consequences of the nuclear accident at the power plant of Fukushima Daiishi. The first thing we notice is that ten months later, the chain of events that followed the earthquake and tsunami of March 11, 2011 can be described with relative accuracy. This description brings a more or less satisfactory answer to the question of ‘How?’ but it is different for the question of ‘Why?’ The answers are puzzling, knowing that this accident occurred in a country with a justified reputation for mastering the most sophisticated technologies and insuring the best products through quality guarantees in industrial processes. Some people claim that the pressure of investors for minimising costs and obtaining as fast and high profitability as possible had led the nuclear operator to take extreme and senseless risks. We do not follow this explanation. It is not in accordance with the usual behaviour of Japanese investors. It is also not coherent with the explicit Japanese policy that nuclear industry should become one of the new exporting industries, beside electronics and cars. These statements led us to deepen the study of the accident and its context beyond the technical and economical rationalities, without of course denying them.