Kansai Electric Power Co. formally notified the Fukui Prefectural Government on Friday that it will decommission the Oi No. 1 and No. 2 reactors.

The utility’s choice to scrap the atomic power plants, which will turn 40 years old in 2019, rather than apply for a two-decade extension, means Kepco units account for four of the 14 reactors nationwide that have been scheduled for destruction since the 2011 Great East Japan Earthquake. Kepco’s Mihama No. 1 and No. 2 reactors are also scheduled for decommissioning.

They would also become the second and third reactors with over a gigawatt of output to be decommissioned in Japan after the 1,100-megawatt No. 6 unit at the crippled Fukushima No. 1 power plant.

Shutting down the two Oi reactors has raised new questions about whether the central government’s goal of having nuclear power account for 20 to 22 percent of Japan’s electricity by 2030 is feasible.

Citing new safety regulations on restarting reactors over 40 years old and technical problems involved with refurbishing the plants to meet those standards, Kansai Electric President Shigeki Iwane told Fukui Gov. Issei Nishikawa that if problems were discovered during regular inspections or while in operation, swift repairs that guaranteed safety would be difficult.

“From a technical perspective, because no effective method was shown to address the problems, and giving top priority to the safety of future operations of the facility and the quality of the reactor components, we decided to decommission the reactors,” Iwane told Nishikawa.

The Kepco chief told reporters afterward that this was the rationale for the decision, rather than the economic efficiency of running the reactors. Kepco did not provide an estimate for how much it would cost to bring the reactor in line with new safety standards. But it has already spent ¥830 billion on upgrading safety at its other seven commercial reactors.

For Fukui Prefecture, where 13 commercial reactors and the Monju prototype fast-breeder reactor are located, Kepco’s decision has raised questions about the local economic impact. Central government subsidies and utility donations to Fukui towns and villages that host nuclear plants have traditionally formed a large portion, sometimes half, of their annual budget. Regular inspections bring engineers and officials to local hotels and restaurants, and many residents work in service businesses connected to plant operations.

Kepco officials assured Nishikawa on Friday that they would explain the decommissioning decision to local firms and include a large number of them in the work — a major issue for the governor and local businesses.

“Efforts on a safety policy and on economic revitalization will lead to local trust,” Nishikawa told Iwane.

How Kepco’s decision will affect the central government’s plans to have nuclear power continue to play an important role over the next decade and a half remains unclear. Minister of Economy, Trade, and Industry Hiroshige Seko told reporters after the decision was announced that eliminating two reactors would not immediately affect the 2030 goal of having nuclear power account for 20 to 22 percent of Japan’s electricity generation.

A Hiroshima High Court ruling earlier this month declared there were volcanic risks associated with the restart of Shikoku Electric Power Co.’s Ikata power plant in Ehime Prefecture, a decision that shut it down. Kepco’s announcement for the Oi reactors will likely force other utilities now seeking restarts to consider further whether the legal costs surrounding restarts and the investment needed to meet current, and possibly future, safety standards will still keep nuclear power a cost-competitive electricity source in the coming years.

But at a news conference in Osaka Friday afternoon, Iwane said Kepco would continue to pursue the restart of Kansai’s remaining reactors.

“In the future, we’re aiming for nuclear power to provide 40 percent of our company’s electricity,” he said.