Japan’s Kashiwazaki-Kariwa Nuclear Plant Restarts After 14 Years

Japan’s nuclear energy landscape is shifting as the Tokyo Electric Power Company (TEPCO) has restarted Unit 6 of the Kashiwazaki-Kariwa nuclear power plant after a 14-year hiatus. This reactor, with a capacity of 1,360 megawatts, is the first to resume operations since the catastrophic 2011 Fukushima disaster. The shutdown followed the devastating 9.1-magnitude Tōhoku earthquake that triggered a tsunami, leading to severe damage and disruptions in power supply.

The Kashiwazaki-Kariwa plant holds the title of the largest nuclear power facility worldwide, with a total capacity of approximately 7,965 megawatts. In the wake of the Fukushima incident, TEPCO has undertaken extensive safety upgrades aimed at mitigating risks associated with earthquakes, tsunamis, and potential terrorist activities. A notable enhancement includes the construction of a reinforced concrete seawall, standing 15 meters high and extending 1,000 meters to safeguard against tsunamis exceeding the predicted maximum of 7-8 meters. Critical infrastructure, such as reactor and turbine buildings, now feature heavy, watertight barriers designed to prevent floodwaters from entering.

As Japan grapples with its energy security, the country is reevaluating its stance on nuclear power. After largely abandoning this energy source post-Fukushima, Japan is now looking to nuclear energy to reduce its dependence on imported fossil fuels and meet rising electricity demands. In 2024, Japan’s expenditure on liquefied natural gas (LNG) and coal imports reached nearly $70 billion. Nuclear power emerges as a cost-effective and domestic alternative, particularly as Japan imports 60-70% of its electricity resources.

Electricity demand in Japan is expected to rise, primarily driven by a surge in AI data center construction and semiconductor manufacturing. Projections indicate that electricity consumption from data centers will more than triple, increasing from 19 terawatt-hours (TWh) in 2024 to between 57 TWh and 66 TWh by 2034. This growth is fueled by significant investments, amounting to 4 trillion yen ($28 billion), from major cloud providers such as Google and Microsoft.

The decision to restart operations at the Kashiwazaki-Kariwa plant marks a critical step in Japan’s energy strategy. As the nation aims for carbon neutrality by 2050, the integration of nuclear power into its energy mix could play a vital role in achieving this goal while ensuring a reliable power supply for its citizens and industries.