Steam Leak Forces Shutdown of Japan's Mihama Nuclear Reactor No. 3

May 08, 2026 | News On Japan

FUKUI, May 08, 2026 (News On Japan) - A steam leak was detected early on May 8th at the Mihama Nuclear Power Plant's Unit 3 in Fukui Prefecture, prompting Kansai Electric Power to manually shut down the reactor.

According to Kansai Electric, steam was found leaking from an area near the high-pressure turbine shortly after 4 a.m., and operators manually stopped the reactor at 4:24 a.m.

The utility said the steam did not originate from water circulating through the reactor core and did not contain radioactive materials. The leak has already been brought under control.

Mihama Unit 3 resumed operations in 2021 after becoming one of Japan's first nuclear reactors to restart despite being more than 40 years old. The reactor has continued operating under extended safety approvals introduced following the 2011 Fukushima nuclear disaster.

Source: TBS

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