
Tohoku Electric Power restarted Onagawa Nuclear Power Plant’s 825MW Unit 2 on at 9 a.m. on November 13, 2024, approximately nine days after halting it due to an incident related to an in-core instrumentation system, the company announced.
The reactor achieved criticality later that day and is now being prepared for the restart of power generation. In spite of the temporary shutdown, Tohoku EPCO continues to work toward its original target of returning the unit into commercial operation in late December 2024.
Onagawa’s Unit 2 was initially restarted on October 29, 2024. The first active nuclear reactor in the Tohoku region since the 2011 Fukushima nuclear disaster did not initially stay online for long, however, as it was halted just a few days later, on November 4, 2024, due to the instrumentation problem.
Tohoku EPCO plans to bring Onagawa Nuclear Power Plant’s other operable unit, the 825MW Unit 3 back online too. However, it has not yet applied for a review of the unit under new safety measures introduced after the 2011 disaster. The company’s 1,100MW Higashidori Nuclear Power Plant, as well as J-Power’s Oma Nuclear Power Plant, which is currently under construction in Tohoku, are currently being reviewed under those measures in preparation for future restart and commissioning.