South Korea’s Nuclear Safety and Security Commission has approved continued operation of Kori nuclear reactors 3 and 4, extending each unit’s operating authorization by 10 years from the end of its original design life. The commission passed the proposal on October 27 by five votes to two. Seven commissioners participated in the final deliberation after one member was absent and another left before the vote.
The authorization allows Kori 3 to operate until September 2034 and Kori 4 until August 2035. Korea Hydro & Nuclear Power applied for continued operation in September 2022, making the decision the conclusion of a review lasting about four years. Kori 3 has been shut down for two years and one month, while Kori 4 has been offline for one year and two months.
- Commission vote
- Five in favor and two opposed
- Kori 3 authorization
- Extended until September 2034
- Kori 4 authorization
- Extended until August 2035
- Restart condition
- Equipment improvements and on-site regulatory confirmation
The two 1,025-megawatt pressurized water reactors began commercial operation in September 1985 and April 1986. Before considering the operating extension, the commission reviewed and approved the accident management plan over three rounds of discussion. Its deliberations also addressed site conditions, atmospheric dispersion and the application of technical standards. The two dissenting commissioners argued that more examination was needed because possible accident scenarios may have been underestimated.
Restart still depends on regulatory checks
The decision is the fourth South Korean approval for continued operation of a reactor whose design life had expired, following Kori 1 in 2008, Wolsong 1 in 2015 and Kori 2 in 2025. It does not permit an immediate restart. The extended authorization establishes the legal operating period, but the reactors must still clear post-approval checks before returning to service.
Korea Hydro & Nuclear Power must complete required equipment improvements and other follow-up measures. The commission plans to inspect the work at the site and confirm compliance before approving restart. The timing of those inspections and the resolution of the safety concerns raised during deliberations will determine when the two units can resume generation.