Photo/Illutration Takahama nuclear power plant in Takahama, Fukui Prefecture (Asahi Shimbun file photo)

The economy ministry proposed a set of new rules on March 24 for a planned regulatory change that could allow nuclear plants to operate beyond the current 60-year limit.

The rules define how to implement new regulations that will take effect in June, with Japan aiming to maximize its nuclear energy capacity by extending the lifespan of aging reactors.

Under the guidelines, periods when a nuclear plant’s operations have been suspended for extended regulatory reviews or a court order will not count toward its 60-year lifespan.

For example, the No. 1 reactor at the Takahama nuclear power plant in Fukui Prefecture remained offline for 12 and a half years for inspections and reviews prompted by the 2011 Great East Japan Earthquake.

Under the new rules, the reactor could now be operated up to 72 years after it first debuted in 1974, a full 12 years beyond the 60-year cap.

There are 24 reactors nationwide, like the Takahama unit, that were idle for more than 10 years following the triple meltdown at the Fukushima No. 1 nuclear power plant triggered by the 2011 earthquake and tsunami.

However, reactors that were taken offline due to operator negligence or misconduct will not be eligible for extensions.

This includes the Kashiwazaki-Kariwa nuclear power plant in Niigata Prefecture, which was shut down for 32 months due to inadequate counter-terrorism measures.

Similarly, the No. 2 reactor at the Tsuruga nuclear power plant in Fukui Prefecture will not be allowed to exclude from its lifespan the 18 months it was suspended due to data falsification.

Under the new rules, the economy minister will approve extensions beyond 60 years on a case-by-case basis.

However, the new guidelines still leave some uncertainties.

Tokyo Electric Power Co. is currently awaiting local approval and pre-operation inspections before restarting the No. 6 and No. 7 reactors at the Kashiwazaki-Kariwa plant.

The ministry will decide on a case-by-case basis whether such periods will count toward the plant’s operational lifespan.

Members of the ministry’s expert panel called for greater transparency in the approval process, advocating for an open debate that includes a third-party adviser.

Japan introduced a strict 40-year limit on reactor lifespans following the Fukushima accident. 

However, the recent policy shift toward greater reliance on nuclear energy has allowed for extensions of up to 20 years, subject to approval from the Nuclear Regulation Authority.

To date, all eight reactors that have applied for extensions have been granted approval to operate for 60 years, effectively making the original limit irrelevant.

The government’s push for longer operational lifespans for reactors is part of its broader energy strategy, which aims to “maximize the use of nuclear power.”

Facing the financial and safety challenges of building new reactors, the government seeks to keep existing ones operational for as long as possible.

However, globally, no nuclear reactor has operated beyond 60 years and questions remain about how to ensure the safety of aging reactors.

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