[5] Following an IAEA inspection in 2012, the agency stated that "The structural elements of the NPS (nuclear power station) were remarkably undamaged given the magnitude of ground motion experienced and the duration and size of this great earthquake".

[7] In 2013 the station operators sent an application request to restart unit 2 at Onagawa to the Japanese Nuclear Regulation Authority (NRA).

Although many of his colleagues regarded 12 meters as sufficient, Hirai's authority eventually prevailed, and Tōhoku Electric spent the extra money to build the 14.8m tsunami wall.

Whereas the mishaps at Fukushima I radically changed public opinion on safety and risks, Tohoku Electric seems to have preserved much of its pre-disaster goodwill in the area of Onagawa.

[5] While the tsunami was more than 13m high at both Fukushima I and the Onagawa power plant,[17] the largest difference between them, apart from the reactor safety systems being designed some twenty years apart, was that the Fukushima I seawall was built to a height of just 5.7m, while the Onagawa power plant seawall was nearly 14 m (46 ft) high and thus successfully blocked the majority of the tsunami from causing severe flood damage.

[29][30][31] The Japanese authorities believe the temporarily heightened values were due to radiation from the Fukushima I nuclear accidents and not from the Onagawa plant.

[34] In 2013 the owners of the station, Tohoku Electric Power Company, sent a restart request to the Nuclear Regulation Authority (NRA) for Onagawa 2.

[8] They can only be restarted after passing an assessment by the Nuclear Regulatory Agency, which in turn is waiting on completion of construction of newly-required safety measures.

[35] Costs of bringing Onagawa 1 to the standards set by the Nuclear Regulation Authority and subsequent maintenance are considered too expensive and time-consuming in comparison to the other two units.

Further complicating the issue, a new rule was set by the NRA in the wake of the Fukushima disaster which limits the operational life of nuclear reactors to 40 years.