Tohoku Electric Power Co. said Thursday it will scrap the idled No. 1 unit at its Onagawa nuclear power plant in the northeastern Japan prefecture of Miyagi, more than 30 years after it began operation.

The company cited difficulties in implementing additional safety measures as well as the relatively low output of the reactor, which would make the business 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 they met at the prefectural government office.

For its resumption, the company has been required to expand safety measures at the unit under stricter standards introduced after the 2011 Fukushima nuclear disaster.

Under the standards, Japanese nuclear reactors are not allowed, in principle, to operate for more than 40 years.

Having entered into operation in June 1984, the boiling water reactor with an output of 524,000 kilowatts is the oldest among four units operated by Tohoku Electric.

The utility said that the No. 1 unit lacked additional space to set up fire extinguishing equipment and infrastructure to secure power supply.

The decommissioning of the reactor is expected to take 30 to 40 years and the utility booked a special loss of around 2.18 billion yen ($19 million) in the first six months of fiscal 2018 through next March for scrapping it.

Harada told a press conference on Sept. 27 that decommissioning was an option as the unit's age made it difficult to implement the required safety measures.

"The equipment is old and power output is relatively small so we saw its decommissioning coming," one official in the power industry said.

In the March 2011 earthquake and tsunami disaster, the basement floors of the Onagawa plant's No. 2 unit were flooded. The company is building a 29-meter sea wall to guard the complex.

Tohoku Electric aims to resume operation of the No. 2 unit at the three-reactor Onagawa plant in fiscal 2020 at the earliest, and the Nuclear Regulation Authority, the country's nuclear watchdog, has been screening its safety measures.