Reactor No. 6 at the Kashiwazaki-Kariwa Nuclear Power Plant, operated by Tokyo Electric Power Company (Tepco) and the world's largest nuclear facility, was suspended on Thursday, hours after its restart on Wednesday. This marked the first time a Tepco-operated reactor had been reactivated since the 2011 Fukushima Daiichi disaster. The suspension followed an alarm sounding during startup procedures due to a control rod-related malfunction, though Tepco confirmed no radioactive impact outside the facility.
Restart and Immediate Suspension
Reactor No. 6 at the Kashiwazaki-Kariwa plant, located in Japan's Niigata region, commenced its restart procedures on Wednesday night. The restart, initially scheduled for Tuesday, was delayed by one day due to an alarm malfunction. However, operations were suspended on Thursday after an alarm sounded again during reactor startup procedures. Tepco reported a glitch related to control rods, specifically after 52 of 205 neutron-absorbing control rods had been removed from the core.
Tepco spokesperson Takashi Kobayashi stated the reactor remained stable, and there was no radioactive impact outside the facility. Takeyuki Inagaki, the Kashiwazaki-Kariwa plant chief, confirmed the shutdown decision was made to ensure safety. Tepco is currently investigating the cause of the incident and has not provided a timeline for resuming operations, indicating a thorough examination of the equipment is required before any further restart attempts. Reactor No. 6 was slated for commercial operation in the following month.
Context of the Fukushima Disaster
The restart effort at Kashiwazaki-Kariwa is significant as it represents the first time a Tepco-operated reactor has been reactivated since the 2011 Fukushima Daiichi nuclear disaster. The disaster, triggered by a 9.0-magnitude earthquake and tsunami, led to meltdowns at the Fukushima plant, resulting in reactor flooding, radiation leakage, and the evacuation of over 150,000 residents. The event contributed to 18,000 fatalities. Following Fukushima, Japan shut down all 54 of its nuclear reactors. Tepco, as the owner of the Fukushima plant, was subsequently ordered to provide extensive damages and cover decommissioning costs, estimated at 22 trillion yen ($139 billion), and has been working to rebuild its reputation amid past criticisms of its safety culture.
Japan's Energy Strategy and Nuclear Resumption
Since 2015, 15 of Japan's 33 operable nuclear reactors have been restarted. This development aligns with Japan's broader strategy to increase atomic energy utilization, aiming to reduce reliance on fossil fuels and advance towards net-zero carbon emissions by 2050. Before 2011, nuclear power generated nearly 30% of Japan's electricity, with plans to increase this to 50% by 2030. The current energy plan targets nuclear power to provide 20% of electricity needs by 2040. Globally, the International Atomic Energy Agency projects a potential doubling of worldwide nuclear power capacity by 2050.
Public Opinion and Safety Concerns
The restart occurred amidst ongoing safety concerns and scrutiny from local residents. Protests were reported outside Tepco's headquarters and the Niigata prefectural assembly. A survey conducted by Niigata prefecture revealed divided public opinion, with 50% of residents supporting the plant's restart and 47% opposing it. Approximately 70% of respondents also expressed concern about Tepco's management of the facility. Niigata Governor Hideyo Hanazumi had announced the prefecture's consent for the restart, a decision that was slated to proceed to a prefectural government assembly in December for further discussion and approval.
Public trust in nuclear power has been affected by the Fukushima disaster and subsequent incidents. The Kashiwazaki-Kariwa plant itself faced incidents in 2023, including an employee losing confidential documents and another mishandling them, which Tepco reported to the Nuclear Regulation Authority (NRA). Earlier in the month, the NRA suspended its review for Chubu Electric's Hamaoka plant after the company was found to have manipulated seismic data.
Future Outlook for Kashiwazaki-Kariwa
If operational, Reactor No. 6 could generate an additional 1.35 million kilowatts of electricity, sufficient to power over a million households. The Kashiwazaki-Kariwa plant has a total output capacity of 8 million kilowatts. Tepco currently plans to resume operations for only two of its seven reactors in the coming years; Reactor No. 7 is not anticipated to be operational until 2030, and the remaining five reactors may face decommissioning. Operating costs for nuclear reactors have increased due to new safety checks requiring significant investments, posing a financial consideration for the government regarding subsidies or consumer charges.