A nuclear power plant reactor that was damaged by the 2011 earthquake and tsunami disaster and idled under stricter safety standards following the Fukushima crisis won approval from the nuclear watchdog on Wednesday for operations to resume.

The No. 2 unit of Tohoku Electric Power Co.’s Onagawa plant in Miyagi Prefecture received the green light after the addition of disaster prevention measures, including a towering seawall that is nearing completion.

The approval, given in a unanimous vote, was the first to be secured by the operator under the revised standards. The reactor is only the second of those damaged in the March 2011 calamity to clear the Nuclear Regulation Authority’s new safety regulations, after the Tokai No. 2 power station in Ibaraki Prefecture.

Before the reactor can be restarted, the plant, which straddles the town of Onagawa and the city of Ishinomaki, still needs to finish installing anti-disaster measures, which are expected to be completed in fiscal 2020, and receive consent from the local governments.

Tohoku Electric expects to spend ¥340 billion ($3.1 billion) on the measures, the bulk of that being spent the seawall — which will run along 800 meters of Pacific coast and rise 29 meters above sea level to guard against tsunami as high as 23.1 meters. In the March 2011 disaster, parts of the basement floors of Onagawa’s No. 2 unit were flooded.

Costs for enhanced safety measures have ballooned and are expected to swell further with the construction of facilities to be used in the event of a terrorist attack, also required under the new safety standards.

The Onagawa plant is the closest nuclear plant to the epicenter of the magnitude 9.0 quake that struck northeastern Japan on March 11, 2011, and heavy shaking triggered an automatic shutdown of its three reactors.

Its No. 2 reactor building suffered flooding from the subsequent 13-meter tsunami, losing up to 70 percent of its capacity to resist earthquakes, and tremors damaged four out of five external power supplies at the plant. But the remaining line was enough to cool the reactors into a cold shutdown, unlike the situation at the Fukushima No. 1 plant run by Tokyo Electric Power Company Holdings Inc., or Tepco, where the triple meltdowns occurred.

Tohoku Electric applied for safety screening for the No. 2 reactor at the Onagawa plant in December 2013, and its restart should save the utility ¥35 billion annually in fuel costs.

The No. 1 reactor is scheduled to be decommissioned, and the utility is still considering whether to seek approval to restart the No. 3 reactor.

The Onagawa No. 2 reactor may become the first boiling water reactor — the same type used at the Fukushima No. 1 plant — to resume operations following the 2011 earthquake and tsunami disaster, which claimed nearly 16,000 lives. More than 2,500 remain missing today. In Onagawa, those killed or missing total more than 800.

Other boiling water reactors at Tepco’s Kashiwazaki-Kariwa plant in Niigata Prefecture and the Tokai No. 2 plant of Japan Atomic Power Co. have already secured NRA approval to resume operations, but have yet to obtain local consent.

Onagawa’s approval will be formalized following a roughly one-month period where the NRA will accept comments from the public. During the meeting Wednesday, NRA Commissioner Shinsuke Yamanaka said the safety of the plant’s structural design had been reviewed carefully, in consideration that the Tohoku region has been hit by big earthquakes in the past.

At Onagawa, more than 80 percent of houses were damaged following the March 2011 tsunami, and locals were divided on whether to back the restart of the plant.

“It is OK to restart if it’s safe,” said Shoichi Chubachi, 82, who still lives in public housing for people who lost their homes in the disaster. “The town has reaped benefits from the nuclear plant. I cannot say I’m opposed.”

“I think there’s sufficient electricity without nuclear power,” said housewife Chisato Uno, 69. “Taking into account our children and grandchildren, no nuclear power is better.”

A woman in her 80s who lives alone expressed concerns. “I can’t drive a car and I cannot evacuate because my legs are weak,” she said.