Nuclear Reactor Halted in Central Japan After Steam Leak

A nuclear reactor at the Mihama power plant in central Japan was shut down on Friday morning after operators detected a steam leak near a high-pressure turbine, the facility’s operator said.

Kansai Electric Power Co. confirmed that the steam did not contain radioactive material and that there was no impact on the external environment or public safety. However, the company has not provided a timeline for the restart of the No. 3 reactor at the Fukui Prefecture facility.

According to the operator, the leak was identified at approximately 4:10 a.m., prompting workers to manually shut down the reactor around 15 minutes later as a precautionary measure.

The Mihama No. 3 reactor, which began operations in 1976, became the first nuclear unit in Japan to operate beyond 40 years under revised safety regulations introduced after the 2011 Fukushima Daiichi nuclear disaster. 

Current rules generally limit reactor lifespans to 40 years, though extensions of up to 20 years may be granted subject to regulatory approval.

Meanwhile, decommissioning work is already underway for two other ageing reactors at the Mihama site, as Japan continues to reassess its long-term nuclear energy strategy in the wake of stricter post-Fukushima safety standards.