Tohoku Electric Power Co. said Thursday it will scrap the idled No. 1 unit at its Onagawa nuclear power plant in Miyagi Prefecture, more than 30 years after it started operations.
The company cited difficulties in taking additional safety measures as well as the relatively small output of the reactor that made it unprofitable.
Tohoku Electric President Hiroya Harada conveyed its decision to Miyagi Gov. Yoshihiro Murai.
"We decided to decommission (the reactor) at a board meeting today. We took into consideration technical restrictions associated with additional safety measures, output and the years in use," Harada said when the two met at the prefectural government office.
Having entered into operation in June 1984, the boiling water reactor with an output of 524,000 kilowatts is the oldest among four units of the utility.
Under stricter post-Fukushima safety standards, reactors are, in principle, not allowed to operate for more than 40 years.
Harada told a news conference on Sept. 27 that he would take into account the need for a stable power supply and economic aspects in deciding whether to restart the No. 1 unit or decommission it.
The basement floors of the Onagawa plant's No. 2 unit were flooded in the March 2011 earthquake and tsunami disaster. The company is building a 29-meter-high sea wall to guard the complex.
Tohoku Electric aims to resume operations of the No. 2 unit at the Onagawa plant in fiscal 2020 at the earliest. The Nuclear Regulation Authority, the country's nuclear watchdog, has been screening its safety measures.