The No. 1 reactor at the Takahama nuclear power plant in Takahama, Fukui Prefecture (Kenji Notsu)

Photo/Illutration The No. 1 and 2 reactors at the Takahama nuclear power plant in Takahama, Fukui Prefecture, on Nov. 8 (Kenta Sujino)

The No. 1 reactor at the Takahama nuclear power plant in Takahama, Fukui Prefecture, which is the oldest operating nuclear plant in Japan, passed the 50-year operating milestone on Nov. 14.

After the 2011 disaster at the Fukushima No. 1 nuclear power plant, the operating period of nuclear plants was set at 40 years, in principle, with a maximum of 60 years in “very exceptional cases.”

But there is a growing trend to make the maximum use of existing nuclear plants, partly because the previous Kishida administration pushed for the nation's return to nuclear power.

The No. 1 reactor at the Takahama nuclear plant, which is operated by Kansai Electric Power Co., began operation on Nov. 14, 1974.

The reactor is a pressurized water reactor-type with an output of 826,000 kilowatts.

The reactor was shut down after the 2011 Great East Japan Earthquake and tsunami.

But it was restarted in July 2023 after being shut down for 12 and a half years, following the Nuclear Regulation Authority extending the operating life of the reactor to 60 years.

The facility management policy for the next 10 years, which is required for operation beyond 50 years, was also approved by the NRA in October this year.

Regarding the 50-plus year operation of the No. 1 reactor, KEPCO released a statement on Nov. 14.

“We will proactively incorporate the latest knowledge from Japan and abroad to improve the safety and reliability of nuclear power plants,” KEPCO said.

KEPCO President Nozomu Mori said during a visit to the town of Mihama in Fukui Prefecture on Nov. 12, “We will continue to place the highest priority on safety.”

Fukui Governor Tatsuji Sugimoto said in a prepared statement, “We will continue to strictly monitor the operation of nuclear power plants in the prefecture.”

The central government had called the maximum 20-year extension of a reactor “extremely exceptional.”

However, the operating lives of eight reactors at four nuclear power plants have been approved so far to be extended.

They are the No. 1, 2, 3, and 4 reactors at the Takahama nuclear plant; the No. 3 reactor at KEPCO’s Mihama nuclear plant in Fukui Prefecture; the Japan Atomic Power Co.’s Tokai No. 2 nuclear plant in Ibaraki Prefecture; and the No. 1 and 2 reactors at Kyushu Electric Power Co.’s Sendai nuclear plant in Kagoshima Prefecture.

The No. 2 reactor at the Takahama nuclear plant will also mark 50 years of operation in November 2025.

KEPCO is in the process of applying for the necessary procedures to operate the reactor for the next 10 years.

Older nuclear power plants are at risk of deterioration, such as thinner piping and reduced strength of concrete structures, and some residents living near the plant have voiced concerns.

In June 2025, a new system will begin under which nuclear power plants can be operated for an extended period beyond 60 years of operation.

This longer lifespan excludes the time that the plant was shut down for NRA’s safety inspections and other reasons from the operating period.

Although it depends on KEPCO’s application and the NRA’s review, Takahama’s No. 1 reactor was shut down for about 12 years after the 2011 earthquake. Thus, it may be able to operate until about 72 years after its start of operation.

The administration of Prime Minister Shigeru Ishiba, who took office in October, is expected to continue the nuclear power policy of the previous Kishida administration.

Domestic nuclear power plants will enter an era in which operation for more than 50 years is not unusual.

(This article was written by Tomoki Morishita, Tsunetaka Sato and Fumi Yada.)

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