South Korea approves life extensions for Kori units 3 and 4, restarts targeted for 2027
Regulatory approval granted
South Korea's Nuclear Safety and Security Commission has approved operating licence extensions for Kori units 3 and 4, located near Busan. The extensions permit unit 3 to operate until September 2034 and unit 4 until August 2035, adding approximately nine to ten years beyond their original 40-year design lives, which expired in September 2024 and August 2025 respectively.
Korea Hydro & Nuclear Power (KHNP) applied for the licence amendments in November 2023. The Korea Institute of Nuclear Safety, a regulatory agency of the commission, subsequently conducted a four-year safety review that included a radiation environmental impact assessment. Both units are 1,025 MWe Westinghouse pressurised water reactors that received their original operating licences in 1984 and 1985.
Independent assessments for each unit
Although the two reactors share the same design, the commission noted that their operating and maintenance histories differ. As a result, the actual condition of structures, systems, and equipment, as well as ageing deterioration and life assessment, were evaluated and reviewed separately for each unit. Commission Chairman Choi Won-ho stated that the regulator would thoroughly inspect the site to verify that agreed facility improvements are implemented in compliance with safety standards.
Restart timeline and facility improvements
KHNP has indicated it plans to restart both units during the first half of 2027. Neither unit is currently in operation. KHNP President Kim Hoe-cheon cited increasing power demand from advanced industries, including semiconductors and artificial intelligence, as well as carbon neutrality objectives, as factors underpinning the case for continued operation. The company stated that facility improvements and regular inspections will be carried out as follow-up procedures ahead of restart.
Site context: decommissioning and recent restart
Kori is a four-unit facility. Unit 1 was permanently shut down in June 2017 after 40 years of operation, becoming the first reactor in South Korea to enter decommissioning. KHNP submitted its dismantling application to the commission in May 2021, and decommissioning approval was granted in June of last year. Unit 2, whose original 40-year permit expired in April 2023, was restarted in April of this year following its own licence extension process.
South Korea currently operates 26 reactors, which together supply approximately one-third of the country's electricity generation.
