Japan has entered a new era of nuclear power generation, as the country's oldest reactor in operation surpassed 50 years of service on Nov. 14.

Despite the 2011 disaster at the Fukushima No. 1 nuclear power plant that prompted a strict 40-year limit on reactor lifespans, all eight applications for extended operation have been approved, rendering the original limit largely symbolic.

With the government's upcoming energy policy updates likely to maximize the use of nuclear power, the practice of extending the lifespan of aging reactors is becoming the new norm.

Globally, around 430 nuclear reactors are in operation, with about 30 already exceeding 50 years of service.

While no reactor has yet operated for more than 60 years, some in the United States have been approved for up to 80 years of operation.

Japan's current energy policy aims to have nuclear power account for 20 to 22 percent of the country's energy mix by fiscal 2030.

However, as of fiscal 2022, nuclear power only made up 5.5 percent of the mix. While 30 reactors would be needed to meet the 2030 target, only 13 have resumed operations.

Given the time required for new construction or replacement, the government plans to maximize the use of existing reactors, even older ones.

A new regulation will be introduced next year to allow reactors to operate beyond 60 years, excluding the time they were offline for regulatory reviews.

For example, the reactor No. 1 at the Takahama nuclear power plant in Fukui Prefecture, which has been halted for 12 years since the Fukushima disaster, could potentially operate until it is 72 years old.

To ensure the safety of these aging reactors, regulators conduct inspections every 10 years for reactors operating beyond 30 years.

This includes reviewing operators' assessments of equipment degradation and their long-term facility management plans.

However, critical components such as the reactor pressure vessel and containment vessel cannot be replaced, and inspections will rely on non-destructive testing methods.

Furthermore, longstanding challenges in Japan’s nuclear power policies persist.

The country’s ambitious project to recycle spent nuclear fuel has faced numerous delays and setbacks.

The Noto Peninsula earthquake in January, which damaged the Shika nuclear power plant in Ishikawa Prefecture, once again highlighted the challenges of evacuating residents in the event of a nuclear accident.

Additionally, the concentration of nuclear plants in southern Fukui Prefecture raises concerns about potential disruptions to the western Japan power grid in the event of a major accident.

REACTOR REPLACEMENT

Despite these challenges, the push for greater reliance on nuclear power is gaining momentum.

Kansai Electric Power Co., one of the country's utilities most reliant on nuclear power, has announced plans to explore replacing its aging reactors.

The company has been aggressively restarting its nuclear power plants, with all seven reactors across its three power stations being brought back online by September 2023.

In fiscal 2023, electricity generated from nuclear power at Kansai Electric increased by 58 percent compared to the previous year, reaching a post-Fukushima meltdown high.

Nuclear power now accounts for 44 percent of the company’s total power generation, surpassing thermal power at 41 percent.

This marks a significant step toward pre-Fukushima levels, when nuclear power accounted for about half the total.

While meeting the stringent new safety regulations is costly, operating nuclear reactors can generate immediate profits for utilities by reducing the fuel costs required for thermal power plants.

For Kansai Electric, every 1 percent increase in the utilization rate of nuclear reactors translates into a cost reduction of 5.1 billion yen ($32.6 million). The company views its aging reactors as a valuable asset.

Kansai Electric President Nozomu Mori has expressed his desire to replace the retired reactors at the utility’s Mihama nuclear power plant in Fukui Prefecture.

“It’s time to start considering the next steps,” Mori said during a recent visit to the local community hosting the plant.

The company had previously initiated a survey in 2010 to replace the plant’s No. 1 reactor, but the project was halted following the Fukushima disaster.

The process of building a new nuclear reactor is lengthy, typically taking 20 years from environmental impact assessments to commercial operation.

"Given the timeline of the project, we need to start taking action sooner rather than later," a Kansai Electric executive said.

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