Fukushima--Two Years Later

Abstract

On 11 March 2011 the Great Tohoku earthquake ( M w 9.1, Global Centroid Moment Tensor) struck northern Japan’s Pacific coast. The estimated number of deaths (including missing) was more than 18,000, and the estimated economic losses were on the order of at least 2×1013 Yen (about US$ 2.5×1011). The tsunami caused a Level 7 nuclear disaster at the Fukushima Dai‐ichi Nuclear Power Station (NPS) which required the evacuation of a large region due to radioactive contamination, and necessitated ongoing efforts to stabilize the situation with the long term goal of decommissioning the destroyed reactors. For a significant period after the accident all nuclear power plants in Japan were shut down; at this moment, two reactors at the Ohi NPS in Fukui Prefecture have been restarted. The Fukushima calamity prompted extensive reexamination and soul searching by the Japanese government, stakeholders, and a variety of public and nongovernmental entities. Scores of reports have been written by individuals, regulators, and organizations worldwide. Now that almost two years have passed, it is time to sum up the lessons learned and to start moving forward—to move from discussions of what went wrong to discussions about what we must do right. In this article, a seismologist (R. J. G.), a probabilistic risk practitioner (W. E.), and a nuclear safety expert (J. N.) pool their respective knowledge to provide a unified view of where we are and where we should go. Some of the lessons to be learned apply particularly to Japan, but in many cases the lessons apply everywhere. In the mid‐1960s Japan, an earthquake‐prone island nation without significant petroleum deposits, was faced with the question of how to secure reliable electric power supplies. The government, with the cooperation of major industry groups, opted to commit heavily to nuclear power. In the face of …