The Onagawa power plant effectively withstood the Fukushima earthquake and tsunami

The reactors at the Onagawa power plant, the closest to the epicenter, did not suffer major damage during the earthquake. Rugged enough to withstand the tsunami, the plant then served as a shelter for local people.

The Onagawa nuclear power plant is the closest power plant to the epicenter of the March 11th, 2011 earthquake, just 60 km away and twice as close as the Fukushima-Daiichi power plant. Its reactors are of the same design and technology, although they are newer. Above all, they are operated by a different company. In particular, the operator did a better job of sizing the plant's tsunami protection according to the available historical data of the region.

During the natural disaster, the populations of villages closest to the nuclear power plant were able to take refuge in the gymnasium of the site, protected from the 14 m high wave - larger than the wave that hit Fukushima-Daiichi - thanks to the combined effect of the voluntary elevation of the site (14.7 m above sea level) and a 14 m anti-tsunami wall (wall of just 5.7 m in Fukushima-Daiichi). Villagers were housed on site for three months until they could find a rehousing solution.

The three reactors of the plant suffered damage, but only the first reactor will not be restarted due to the costs of upgrading to new standards which are considered too high compared to the power and remaining operating life of this reactor. The second reactor restarted after repair and upgrading work in October 2024. For the third, a seismic verification campaign is underway and the operator has not yet requested permission to restart.