Korean reactor cleared for extended operation

Kori unit 2 - South Korea's second nuclear power reactor - began commercial operation in August 1983. The 685 MWe pressurised water reactor's operating permit expired on 8 April 2023, and it has remained offline since. Korea Hydro & Nuclear Power (KHNP) submitted a safety assessment report for continued operation of Kori 2 in April 2022 and applied for a permit for continued operation, including the results of a public opinion survey on the radiation environmental impact assessment.

The Korea Institute of Nuclear Safety (KINS) - a regulatory agency under the Nuclear Safety and Security Commission (NSSC) - conducted a safety review between April 2022 to July 2025, and the Nuclear Safety Expert Committee conducted a preliminary review of the KINS review results for between March 2025 to September 2025 and determined that the review results were appropriate.

The NSSC previously considered the proposal for continued operation of Kori 2 at meetings on 25 September and 23 October, but failed to reach a decision. However, at a meeting on Thursday, the commission concluded that the unit "maintains sufficient safety margins" and meets safety requirements and decided to approve the continued operation of Kori 2 until 8 April 2033.

KHNP said it plans to restart Kori 2 in February 2026, after completing ongoing facility improvements and confirming safety through regular inspections by regulatory agencies. "Furthermore, the plant's safety and performance will be further enhanced during this period of continued operation through continuous facility improvements and thorough implementation of safety measures," it noted.

The decision to allow the continued operation of Kori 2 is expected to set a precedent for the extended operation of other South Korean reactors. 

KHNP is currently submitting safety assessment reports for the continued operation of nine other nuclear power units (Kori 3 and 4, Hanbit 1 and 2, Hanul 1 and 2, and Wolsong 2, 3, and 4), whose operating licences expire before 2030, to the NSSC for review. 

Operation of units 3 and 4 at the Kori plant was suspended in September 2024 and August this year, respectively, as their 40-year design lives had expired.

Unit 1 of the Kori plant was permanently shut down in June 2017, after 40 years of operation, and become the first South Korean reactor to enter decommissioning. KHNP submitted its application to dismantle the unit to the NSSC in May 2021. The regulator approved the decommissioning of Kori 1 in June this year.

"Continued operation will contribute to the national economy as a stable energy source for future power demand growth, such as for AI and data centres, and will play a significant role in achieving carbon neutrality by 2050," said Jeon Dae-wook, acting president of KHNP. "We will do our best to restart Kori unit 2 at the right time, with safety as our top priority."