Onagawa-2 Resumes Power Generation: First BWR to Operate in Japan Since Introduction of New Regulatory Standards in 2013

On November 15, the Onagawa-2 Nuclear Power Plant (BWR, 825MW), owned and operated by the Tohoku Electric Power Co., returned to service (i.e., it started generating power again).

In the wake of the giant quake of March 11, 2011-referred to officially as the Great East Japan Earthquake-Japan introduced new regulatory standards in 2013. This was the first time since then that a boiling water reactor (BWR) had been restarted in the country.

From now on, the unit is expected to return to full commercial operation as early as next month (December 2024), after the Nuclear Regulation Authority (NRA) of Japan finishes an integrated performance test on it.

It has taken Onagawa-2 almost 14 years to restart since it was originally shut down for a periodic inspection in October 2010. When the big earthquake struck, the unit was about to be restarted after that inspection, but that plan was scrammed automatically.

In December 2013, the power company filed an application with the NRA for a compatibility examination with the country's new regulatory standards. After an examination lasting more than six years, the government finally gave Tohoku Electric Power permission in February 2020 to make changes to the reactor installation.

In November of the same year, the governor of Miyagi Prefecture (where the unit is located) and local siting municipalities expressed their agreement to the restart. In May 2024, a breakwater 29m above sea level was completed, along with work on other safety measures.

Almost a month ago, on October 29, the power company started up the unit, but then suspended its operation temporarily on November 3 to inspect the facility. On November 13, the reactor was restarted again, and electricity generation resumed two days later, at 6:00 p.m. on November 15.

Tohoku Electric Power marked the restart of power generation at Onagawa-2 by releasing the following statement, commenting on its reflections on its experiences dealing with natural hazards: "The company has positioned this as a 'fresh start' to show its determination to achieve a rebirth, as well as to learn from its predecessors who got the reactor up and running from zero, to strengthen ties with local communities, and to reflect in its own operations the lessons learned from the nuclear accident at the Fukushima Daiichi NPPs of the Tokyo Electric Power Co. (TEPCO)."

Based on the lessons from the 2011 earthquake disaster, the power company then said that it would strive to further enhance safety at its own NPPs.

Minister MUTO Yoji of the Ministry of Economy, Trade and Industry (METI) also released a statement on Onagawa-2's restart. Noting the vulnerability of power supplies in eastern Japan, as well as disparities in power rates between eastern and western Japan, among other issues, he called the restart "a major turning point and significant step."

As the leader of the ministry responsible for securing stable energy supplies in the country, he also expressed his gratitude to the siting municipalities for their understanding and cooperation, as follows: "The government will continue to pursue the restart of those NPPs whose safety has been confirmed."

Meanwhile, at a regular press conference held on November 15, Chairman HAYASHI Kingo of the Federation of Electric Power Companies (FEPC) of Japan made a statement in which he emphasized the significance of restarting Onagawa-2, saying, "The industry is also deeply impressed that an NPP that had been suspended for such a long time has now been successfully restarted."

In his comments, Hayashi demonstrated the determination of the nation's nuclear industry in working toward the early restart of other NPPs that remain idle, including Chugoku Electric Power's Shimane-2, while obtaining understanding from siting areas.

Another message on the unit's restart was released by President MASUI Hideki of the Japan Atomic Industrial Forum (JAIF), who said, "It is a highly significant step for Japan in maintaining and strengthening its supply chains and developing its human resources."