Photo/Illutration Tohoku Electric Power Co.’s Onagawa nuclear power plant in Onagawa, Miyagi Prefecture, in 2024 (Asahi Shimbun file photo)

Tohoku Electric Power Co. announced it will probably shut down the No. 2 reactor at its Onagawa nuclear power plant in Miyagi Prefecture in December 2026 because it failed to meet a key safety requirement.

The reactor was only restarted last October.

The utility has fallen afoul of a Nuclear Regulation Authority requirement that operators build anti-terrorism facilities at nuclear sites.

The edict was imposed in the aftermath of the triple meltdown at the Fukushima No. 1 nuclear power plant in 2011. 

Tohoku Electric has until Dec. 22 next year to rectify the situation and finish building the facility on-site. If it fails to meet the deadline, it will be forced to discontinue operations.

The company said Oct. 17 that the construction could not be completed on time.

The new safety standards set by the NRA mandate the installation of a “specified severe accident response facility,” known as “Tokuju,” to serve as a backup facility in the event of a terrorist act such as an aircraft collision with the reactor building.

The No. 2 reactor passed the NRA’s review in February 2020.

Under the NRA’s rules, operations can be conducted for a time even without the Tokuju facility.

Tohoku Electric was given until Dec. 22, 2026, to construct the site, a full five years after it gained approval of the main reactor's construction plan on Dec. 23, 2021.

The company stated that it was hampered by work-style reforms in the construction industry.

The revised construction completion date is now set for August 2028, meaning operations will be suspended for approximately one year and eight months until then.

After the No. 2 reactor is shut down, the company plans to supplement electricity supply by increasing the output of its thermal power plants.

As a result, it estimates costs will increase by about 6 billion yen ($40 million) per month.

Regarding the impact on electricity rates, Hiroaki Aoki, head of Tohoku Electric’s nuclear power division, said at a news conference, “We will make efforts so they do not change.”

In the meantime, a lobby group for the nuclear industry, including Tohoku Electric, is moving to avoid the suspension of nuclear power plant operations due to the missed deadline.

At a meeting of the NRA on Oct. 9, the group requested a three-year extension to the deadline, pushing it from five years to eight years after the main reactor’s approval.

In response, the NRA will soon begin discussions on the merits of an extension.

The industry group explained that, in addition to a shortfall in workers in the construction industry, limits placed on overtime work are expected to extend the construction period by up to two years and nine months.

“The labor shortage and work-style reforms are external factors, and they are difficult to manage through our efforts alone,” Tohoku Electric’s Aoki said. “We are pushing for a review.” 

At a news conference on Oct. 15, NRA Chairman Shinsuke Yamanaka stated, “When asked if these are external factors significant enough to extend the deadline, I did not feel that they were.” 

(This article was written by Ryo Oyama and Yusuke Ogawa.)