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Is there any reason to delay restarting Kori-2?

Published: 04 Nov. 2025, 00:04

Jeong Jae-jun

The author is a professor of mechanical engineering at Pusan National University.

The Nuclear Safety and Security Commission (NSSC) postponed its decision on whether to extend the operation of the Kori Nuclear Power Plant Unit 2 on Oct. 23. It was the second delay following a similar decision in September. As a result, the reactivation of Kori-2, which has been offline for two years and seven months due to the expiration of its operating license, will be pushed back further. Still, the NSSC approved the plant’s Severe Accident Management Plan, which has been under review for more than six years.

The photo shows the Kori Unit 2 reactor, center, and the Kori Unit 1 reactor, right. [SONG BONG-GEUN]

A continued operation license allows a nuclear plant to run for an additional 10 years after its original operating period expires, provided that outdated equipment is replaced or upgraded and safety is thoroughly evaluated. The accident management plan is a comprehensive report detailing how to respond to severe accidents, and became legally required in 2016. While international organizations recommend such plans, no other country has made them mandatory by law. This is often cited as evidence that Korea enforces the world’s strictest nuclear safety standards. Although the plan is not legally a prerequisite for license renewal, it has been a significant hurdle. With its approval, that barrier is now gone.

Kori-2 began commercial operation in April 1983, ran for 40 years, and has been under maintenance since it was shut down in April 2023. Korea Hydro and Nuclear Power said it invested more than 170 billion won to upgrade systems for continued operation in 2017.

Extending the life of nuclear plants is neither unusual nor unsafe. Plants that have operated safely for 40 years are often deemed reliable and, once key systems are upgraded, can continue to run for several more decades. The economic benefits are clear. According to the OECD Nuclear Energy Agency, electricity generated from extended-operation plants costs about 42 percent less than building and operating new reactors. As of 2024, 238 of the world’s 439 nuclear reactors are operating under extended licenses.

In the United States, nuclear plants are initially licensed for 40 years, with two 20-year renewals possible. Of its 94 reactors, 86 have already extended their licenses to 60 years of operation. Of these, 51 reactors are older than Kori-2. Second renewals — allowing up to 80 years of operation — are also being granted.

A symbolic example is Three Mile Island (TMI) Unit 1 in Pennsylvania. It sits next to TMI Unit 2, the site of the worst nuclear accident in U.S. history in 1979. Although TMI-1 was permanently shut down in 2019, it is now being prepared for restart in 2028 after refurbishment. Microsoft has signed a 20-year power purchase agreement with the plant’s operator to secure electricity for its expanding data centers. This reflects a broader reality of the AI era: Securing carbon-free, stable, 24-hour electricity is becoming urgent.

France, Canada, and Switzerland are following similar paths. Switzerland operates all four of its reactors under extended licenses. Beznau Unit 1, which began operating in 1969, is the world’s oldest active reactor at 56 years — 14 years older than Kori-2 — and is still considered safe and economical.

This picture taken on July 9, 2019, shows a general view of Switzerland's Beznau nuclear plant near Dottingen. Switzerland's Beznau nuclear plant, one of the oldest in the world, will keep running until 2033, its operator announced on December 5, 2024, as environmentalists argued it should be shut down ″immediately″. [AFP/YONHAP]

Korea, by contrast, has no reactors currently operating under extended licenses. While Kori-1 and Wolsong-1 were briefly extended before being shut down under the Moon Jae-in administration, the process for Kori-2 is not technically unprecedented. When compared internationally, Kori-2 is not even considered an old reactor. With the accident management plan approved, the NSSC should make a swift decision based on science and facts, without excessive caution.

Industrial electricity prices in Korea have risen more than 70 percent over the past three years. Even so, nuclear power remains the cheapest source of electricity compared to coal, natural gas, hydropower or renewables. Replacing Kori-2 with LNG power would cost an additional 500 billion won per year and emit more greenhouse gases. Nuclear energy remains a pillar of both the economy and the environment.

Extending Kori-2’s operation would also help sustain Korea’s nuclear industry ecosystem. In that sense, it offers not only economic and environmental benefits but also industrial resilience — truly a case of gaining several advantages with one decision.

This article was originally written in Korean and translated by a bilingual reporter with the help of generative AI tools. It was then edited by a native English-speaking editor. All AI-assisted translations are reviewed and refined by our newsroom.