Tepco considering fate of oldest Kashiwazaki-Kariwa units

"We informed the assembly that deliberations are under way in regard to the direction of decommissioning of Kashiwazaki-Kariwa Nuclear Power Station units 1 and 2," Tepco said in a statement. "Decisions related to this matter shall be made after ascertaining the impact that it will have on overall business management, including the restart of unit 6, and upon giving explanations to stakeholders, and obtaining their understanding and cooperation."

Kashiwazaki-Kariwa units 1 and 2 are 1,067 MW boiling water reactors that began supplying power in February 1985 and February 1990, respectively.

Kashiwazaki-Kariwa was unaffected by the March 2011 earthquake and tsunami which damaged the Fukushima Daiichi plant, although the plant's reactors were previously all offline for up to three years following the 2007 Niigata-Chuetsu earthquake, which caused damage to the site but did not damage the reactors themselves. While the units were offline, work was carried out to improve the plant's earthquake resistance. All units have remained offline since the Fukushima Daichii accident.

Although it has worked on the other units at the Kashiwazaki-Kariwa site, Tepco is concentrating its resources on units 6 and 7 while it deals with the clean-up at Fukushima Daiichi. Restarting those two Kashiwazaki-Kariwa units - which have been offline for periodic inspections since March 2012 and August 2011, respectively - would increase the company's earnings by an estimated JPY100 billion (USD670 million) per year.

Tepco is now prioritising restarting Kashiwazaki-Kariwa unit 6, where fuel loading was completed in June. The company has until September 2029 to implement anti-terrorism safety measures at unit 6, and it could operate until that time, pending local approval. However, Tepco has yet to obtain the Niigata prefectural government's consent.

In June 2017, Kashiwazaki Mayor Masahiro Sakurai requested Tepco submit a decommissioning plan for at least one of Kashiwazaki-Kariwa units 1-5 within two years as a precondition for approving the restart of units 6 and 7. In August 2019, Tepco submitted a report setting out the basic policy for the restart of the operation and decommissioning of units at the Kashiwazaki-Kariwa plant. The company said at that time it could not predict when it would be able to secure non-fossil fuel power sources of sufficient scale to meet long-term demand. However, it said that when it is able to predict when it can secure sufficient non-fossil fuel power sources, "decommissioning of one or more of units 1-5" will be an option, within five years of the restart of units 6 and 7.