Japan has begun the process of switching on the world’s largest nuclear power plant for the first time since the 2011 Fukushima disaster forced the shutdown of all its reactors.
Reactor No. 6 at the Kashiwazaki-Kariwa plant, northwest of Tokyo, was briefly activated on Jan. 21 before an alarm was triggered, halting the process. Operations are postponed while the cause is being investigated, though the reactor is still expected to begin commercial generation by late February. Residents and activists have expressed strong opposition to the restart, raising safety concerns.
The move reflects Japan’s effort to rebuild nuclear capacity after the Fukushima Daiichi meltdown, which led to the suspension of all 54 reactors. Seeking to cut greenhouse gas emissions and reduce its reliance on imported fuel, Japan has gradually restarted reactors under tougher safety standards. Since 2015, 15 of the country’s 33 operable reactors have resumed operations. Even so, nuclear power accounted for only 8.5% of Japan’s electricity in 2023. The government aims to raise that share to about 20% by 2040.
Prime Minister Sanae Takaichi has emphasized nuclear energy as a key component of Japan’s energy security, particularly as demand from data centers and semiconductor production continues to increase. Supporters also argue that nuclear power is more reliable than renewable energy in Japan’s mountainous terrain. Critics counter that the emphasis on nuclear energy has slowed investment in renewables, while stricter safety rules have sharply increased operating costs.
Public opinion remains divided, shaped by lingering fears and recent scandals involving data handling and regulatory violations at nuclear facilities. New safeguards, including taller seawalls and watertight doors, aim to prevent another Fukushima, but experts warn that climate change and unforeseen disasters could still test those defenses.