In January 2026, when Japan started up one of the reactors at the Kashiwazaki-Kariwa nuclear power plant, it marked the beginning of what many thought would be Japan’s nuclear revival. Kashiwazaki-Kariwa is the largest nuclear power station in the world in terms of potential generating capacity. Its restart was intended to enhance Japan’s energy security after years of reactor shutdowns following the 2011 Fukushima disaster.
Japan’s fragile nuclear revival: How much progress is being made?
Reactor No. 6 has been out of operation for approximately 15 years. Tokyo Electric Power Company Holdings (TEPCO), which is the operator of the damaged Fukushima Daiichi Nuclear Station, successfully completed all regulatory tests to allow for the restarting of the reactor on January 21, 2026.
The reactor start-up was halted just hours later due to a technical malfunction, indicating how fragile Japan’s nuclear industry continues to be.
At this point, operators were preparing to remove the neutron-absorbing control rods from the reactor; these rods are necessary for regulating the amount of nuclear fission occurring. However, during the removal process, an alarm sounded to indicate that a malfunction had occurred in the control rod system. As a result, the operators ceased all startup activities, and TEPCO then decided to completely shut down the reactor to investigate the cause of the malfunction.
TEPCO emphasized that the incident was not a safety hazard and there was no radiation leak
In addition, according to TEPCO, the reactor remained in a stable condition throughout the process. Nevertheless, the fact that the reactor start-up was halted so quickly raised further concern because the start-up had previously been delayed due to another problem associated with the control rod system. The multiple technical problems have raised additional concerns regarding the reliability of the equipment and the operational readiness of the plant, despite having spent significant time upgrading and conducting safety reviews over the past several years.
Located in Niigata Prefecture (about 220 km northwest of Tokyo), the Kashiwazaki-Kariwa nuclear power station is a key component of Japan’s national energy strategy. When the seven reactors at Kashiwazaki-Kariwa operate at maximum capacity, they will be capable of producing more than 8 gigawatts of electric power — sufficient to provide electrical power to millions of homes in the Tokyo area.
Before the 2011 Fukushima accident, nuclear power supplied about 29% of Japan’s electricity and provided a reliable source of baseload power for an island nation heavily reliant on imported fuels. Of Japan’s 33 operable nuclear reactors, 15 have returned to service under tighter safety guidelines following the Fukushima disaster.
Public unrest: Concerns around seismic risks and corporate oversight
The restarting of the reactors at Kashiwazaki-Kariwa was particularly significant because it was the first reactor to begin operating under new regulations at a TEPCO-owned nuclear power station since Fukushima. This made it a test of restored public confidence and a symbol of the nuclear industry’s renewed commitment to safe operations.
While some local residents opposed the restart, others protested the event due to their continuing concerns regarding seismic risks and corporate oversight. The incident illustrates the broader challenge Japan faces. Due to increased industrial activity and increasing use of high-power technologies, such as artificial intelligence, Japan’s electricity consumption is growing rapidly.
The Japanese government believes that nuclear power will play a major role in reducing its reliance on foreign fossil fuels and achieving its goal of becoming carbon-neutral by 2050. However, the current restart of the Kashiwazaki-Kariwa nuclear power station demonstrates that even the most carefully monitored facilities continue to be subject to unforeseen difficulties. What was intended to serve as a reliable source of electricity instead serves as a reminder that Japan’s nuclear future remains uncertain.
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