Onagawa No. 2 Reactor Shut Down for Inspection, Steam Seen in Turbine Building

2026-05-17

Tohoku Electric Power Co. said it has brought the reactor at Onagawa Nuclear Power Plant Unit 2 (Onagawa Town and Ishinomaki City, Miyagi Prefecture) to a cold shutdown for inspection. Steam containing radioactive material has been generated in the turbine building, and the cause is under investigation. No release outside the facility has been confirmed, and the company says there is no impact on the surrounding area.

Steam from tank, seen before quake

According to the company, around 5:10 p.m. on the 15th, steam came from a tank that separates steam used to turn the power-generating turbine and stores moisture. The valve connected to the tank was retightened, but the steam did not stop. The trouble occurred before the earthquake that hit Miyagi Prefecture and other areas after 8 p.m. that day, and the company says it is unrelated to the quake.

Shutdown on the 16th, cause under investigation

Tohoku Electric shut down the reactor on the 16th and is investigating the cause. Unit 2 entered regular inspection in January, and the reactor was restarted on May 11. The regular inspection was nearly complete, and preparations were underway to resume commercial operation in early June.

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