[News Issue] 'Onagawa Nuclear Power Plant' Restarted After 13 Years Since the Great East Japan Earthquake

March 11, 2011.

A massive earthquake with a magnitude of 9.0 on the Richter scale, the largest ever recorded in Japan, struck the Tohoku region. The epicenter was located about 24 km underwater, 130 km southeast of Oshika Peninsula in Miyagi Prefecture, Japan. The earthquake triggered a gigantic tsunami that swept ashore, causing large-scale casualties, building collapses, and major fires. Nuclear power plants near the epicenter were also damaged by the tsunami.

[Image source=Yonhap News]

Among them, the Fukushima Nuclear Power Plant's basement was flooded, cutting off power supply and leading to explosions and radioactive leaks. Since then, the Japanese government has not restarted nuclear power plants in the affected areas. The decision to restart nuclear power plants in the areas affected by the Great East Japan Earthquake comes 13 years later.

October 29, 2024.

Tohoku Electric Power Company removed control rods that suppress nuclear fission reactions and started the reactor at Unit 2 of the Onagawa Nuclear Power Plant in Miyagi Prefecture. Power generation is expected to resume as early as November 7, with commercial operation beginning in December.

The Onagawa Nuclear Power Plant was hit by a tsunami reaching a maximum height of 13 meters during the Great East Japan Earthquake, flooding the basement of the Unit 2 reactor building. It is closer to the epicenter than the Fukushima plant, which experienced radioactive leaks, but the reactor automatically shut down at the time, preventing explosions and radioactive leaks like those at Fukushima. However, due to safety concerns and the Japanese government's "nuclear zero" policy, operations have been suspended since then. Since then, Onagawa has implemented safety measures such as raising the seawall to 29 meters above sea level, and passed the Nuclear Regulation Authority's review in 2020, paving the way for the plant's restart.

After the Great East Japan Earthquake, Japan halted operations of all 54 nuclear reactors nationwide. Then, in 2015, it resumed operations at the Sendai Nuclear Power Plant in Kagoshima Prefecture, Kyushu, returning to being a "nuclear power country." Twelve reactors that were operating before the Fukushima accident have been restarted, all located in areas far from the Great East Japan Earthquake region. This is the first time a nuclear power plant in the affected region of the Great East Japan Earthquake has been restarted, and including Onagawa Unit 2, the total number of restarted reactors is 13.