15 units have now returned to service since 2011 Fukushima disaster
Unit 6 at the Kashiwazaki Kariwa nuclear power station in Niigata Prefecture, central Japan, restarted commercial operations on 16 April after a hiatus of more than 14 years.
Tokyo Electric Power Company (Tepco) said the 1,315 MW Advanced Boiling Water Reactor (ABWR), which had been offline since March 2012, officially resumed commercial operation at 16.00 local time after it was confirmed earlier in the day that there were no abnormalities with the reactor, generator or turbine.
An official from the Nuclear Regulation Authority handed the certification of the final check to the plant’s chief, Takeyuki Inagaki, reports in Japan said.
This marked the first time a Tepco reactor has resumed commercial operation since the March 2011 triple meltdown at the company’s Fukushima nuclear station in northeastern Japan.
The resumption of commercial operations was initially scheduled for late February but was delayed by about 50 days following two postponements due to technical issues.
Workers at the plant originally began restarting the unit on 21 January, but the process had to be suspended hours later due to a malfunction related to control rods, which are essential to starting up and shutting down reactors, Tepco said.
The Japan Times said the fault was caused by an electrical problem inside the panel used to operate and monitor the unit’s control rods.
Tepco said it plans to operate Kashiwazaki Kariwa-6 for one year until its next planned inspection in April 2027.
Tepco said in a statement on 16 April that “the regrets and lessons learned from the Fukushima-Daiichi nuclear power station accident are foundational to Tepco’s management and safety philosophy”.
Kashiwazaki Kariwa is the world’s largest nuclear power station by capacity. According to the International Atomic Energy Agency, its seven BWR units have a combined net capacity of 7,965 MW.
The facility served as an important energy source to supply electricity to the Tokyo metropolitan area before the 2011 earthquake, tsunami and nuclear accident at Fukushima-Daiichi.
Tepco wants to bring the station back online and said in 2020 it was concentrating its resources on restarting the newer Units 6 and 7.
Background: 15 Units Back Online
The plant’s restart means Japan has returned 15 units to service since the March 2011 Fukushima disaster. They are: Kashiwazaki Kariwa-6 (Tepco), Onagawa-2 (Tohoku Electric Power), Shimane-2 (Chugoku Electric Power), Mihama-3, Takahama-1, -2, -3, -4, and Ohi-3, -4 (Kansai Electric Power), Ikata-3 (Shikoku Electric Power), Genkai-3, -4, and Sendai-1 -2 (Kyushu Electric Power).
Before the Fukushima disaster Japan’s fleet of 54 nuclear plants generated about 30% of the country’s electricity, but were all shut down for safety checks following the accident.
According to the International Atomic Energy Agency, the figure for 2023, was 5.5%, but the government want to see this climb to 20%.
Japan’s prime minister Sanae Takaichi has said she will push for the accelerated revival of nuclear power with reactor restarts key to reducing costly fuel imports.
The Kashiwazaki Kariwa nuclear power station in Niigata Prefecture, central Japan. Courtesy Tepco.
