South Korea's Nuclear Safety and Security Commission approved a 10-year extension for Kori nuclear power plant units 3 and 4. The 1,025 MWe Westinghouse pressurized water reactors are near Busan. They received operating licenses in 1984 and 1985, and their 40-year design lives expired in September 2024 and August 2025, respectively. Both units are currently not in operation.

The extensions allow unit 3 to operate until September 2034 and unit 4 until August 2035. Korea Hydro & Nuclear Power said it plans to restart the units in the first half of 2027. The company applied for the license amendment in November 2023.

The Korea Institute of Nuclear Safety, a regulatory agency of the commission, conducted a four-year safety review, including a radiation environmental impact assessment. The commission said that although the units share a design, their operating and maintenance histories differ, so the condition and aging of structures, systems and equipment were evaluated separately.

Commission chairman Choi Won-ho said the regulator would "thoroughly inspect the site to ensure that Kori units 3 and 4 are operated safely" and verify that facility improvements meet safety standards.