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Kori-2 green light may open door to further approval of extended reactor operations

Published: 13 Nov. 2025, 19:53

Choi Won-ho, chair of the Nuclear Safety and Security Commission (NSSC), delivers opening remarks during the 224th plenary meeting at the commission’s office in Jung District, central Seoul, on Nov. 13. The NSSC approved the lifetime extension of Kori-2 Nuclear Power Plant during the meeting. [NEWS1]

The Nuclear Safety and Security Commission (NSSC) on Thursday approved the continued operation of the Kori-2 nuclear reactor in Busan — a unit that has been offline for two years and seven months following the expiration of its design life span.

The decision, made during the commission’s third deliberation on the agenda, raises the likelihood that Korea Hydro & Nuclear Power (KHNP) will receive approval to extend the operation of nine additional reactors, including Kori-3 and Kori-4. The market welcomed the move as a key step toward ensuring stable and affordable power — a critical factor in building AI infrastructure.

The NSSC held its 224th meeting in central Seoul and approved the operations agenda item. As a result, the reactor’s life span will be extended by 10 years — from its design expiration date of April 2023 to April 2033. KHNP is expected to restart operations after about three months of preparations, including facility upgrades.

The commission stated that it has “confirmed that sufficient safety margins were secured during the extended operation period for Kori-2,” adding that a radiological environmental impact assessment met all safety standards.

Only six of the commission’s nine members participated in the meeting, as several members’ terms had expired. While some voiced dissent — including Commissioner Jin Jae-yong, who argued that comparisons to conditions at the time of the original operating license were necessary — NSSC Chair Choi Won-ho stated that “past data has virtually no relevance to evaluating the impact of future operations.” A vote ended with five in favor and one against. The meeting was briefly disrupted by environmental activists who had signed up for on-site observation but protested against the extension and were removed from the hall.

Kori-2, which began commercial operation in 1983, has a capacity of 685 megawatts. While smaller than Korea’s current mainstay nuclear plants rated at 1,400 megawatts, it is capable of generating power equivalent to that of dozens — or even hundreds — of large-scale solar farms.

A view of the Kori-2 nuclear reactor, left, seen from Gijang County, Busan, on Nov. 13. [SONG BONG-GEUN]

Members of civic and environmental groups call for an end to the lifetime extension of Kori-2 Nuclear Power Plant during a plenary meeting of the Nuclear Safety and Security Commission (NSSC) in Jung District, central Seoul, on Nov. 13. The NSSC approved the extension during the meeting. [NEWS1]

This is the third time that Korea has approved a life span extension for a reactor that has reached the end of its design life. Kori-1 and Wolsong-1 were previously granted extensions in 2008 and 2015, respectively, but both were permanently shut down under the Moon Jae-in administration’s nuclear phaseout policy. Kori-2 was not permanently closed, but its request to continue operations was delayed — resulting in an operational halt when its design life expired before the NSSC could complete its review.

Now, the effective extension period for Kori-2 is less than eight years, as the 10-year extension is counted from the design expiration date, not from the date of approval.

Although the restart will occur later than initially planned, Thursday’s decision is expected to positively impact KHNP’s applications to extend the life of nine other reactors. Kori-3 and Kori-4 have already halted operations after their design life spans expired. Hanbit-1 is scheduled to reach the end of its design life in December and must receive approval before then to avoid shutdown.

“Extending the life span of existing reactors — provided their safety is ensured — is the most effective way to meet energy demands for AI infrastructure expansion and achieve Korea’s 2035 greenhouse gas reduction targets," said Jeong Dong-wook, a professor of energy systems engineering at Chung-Ang University. “The green light has now been given for the remaining nine units as well.”

Shin-Kori Units 3 and 4, along with Unit 5 under construction, are seen at Shin-Kori Nuclear Power Plant in Ulju County, Ulsan, on Nov. 9, 2022. [YONHAP]

Amid a global race to secure GPUs, considered the core of AI, Korea recently secured a priority allocation of 260,000 high-end GPUs from Nvidia. This move has brought Korea a step closer to achieving the government’s ambition of becoming one of the global top three AI powers.

However, concerns have grown over the electricity supply to power those GPUs. The NSSC has faced criticism for repeatedly delaying approval for extending the life of reactors that could help meet this demand. This led to doubts about the Lee Jae Myung administration’s so-called nuclear pragmatism initiative, under which the government vowed to expand renewable energy while recognizing the realistic role of nuclear power.

With Thursday’s decision, Korea has cleared a major hurdle in expanding AI infrastructure. Operating a single hyperscale AI data center typically requires about 500 megawatts of power. The 260,000 GPUs Korea will receive are estimated to require between 500 and 600 megawatts — a level of supply Kori-2 is capable of covering with its 685-megawatt capacity, thereby quickly alleviating potential power bottlenecks.

“Operating 260,000 GPUs will require at least 260 megawatts of power — assuming 1 kilowatt per GPU — and more than 500 megawatts when accounting for data center cooling," said Jeong Yong-hoon, a professor of nuclear and quantum engineering at KAIST. "The challenge is securing that level of capacity within the next five years — and the fastest, most cost-effective way to do that is by extending the life of existing nuclear reactors.”

Units 3 and 4 of the Kori Nuclear Power Plant in Gijang County, Busan, are seen on Sept. 3, 2020. [SONG BONG-GEUN]

Other experts also echoed the sentiment.

“It is difficult to achieve national competitiveness in AI without relying on economically viable and safe nuclear power," said Moon Joo-hyun, professor of energy engineering at Dankook University, noting that in countries like the United States, many reactors have operated for over 40 years — and older units are retrofitted with the latest safety systems after receiving approval for extended operation.

Chung Bum-jin, a professor of nuclear engineering at Kyung Hee University, added, “Predictability is one of the most important factors for companies making AI-related investments. That is why energy policies and regulations must be consistent and foreseeable.”

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.
BY KANG KWANG-WOO [[email protected]]