What would a 10-year lifespan extension allow Kori-3 and Kori-4 to do?

If the Nuclear Safety and Security Commission approves the request, Kori-3 could operate until September 2034 and Kori-4 until August 2035. The request covers restarting and operating the two reactors beyond their designed 40-year lifespans.

When did Kori-3 and Kori-4 stop operating or reach the end of their lifespans?

Kori-3 was suspended on Sept. 28, 2024. Kori-4’s operational lifespan expired on Aug. 6, 2025.

What safety preparations did regulators review for Kori-3 and Kori-4 before considering their lifespan extensions?

Earlier this month, the commission approved an accident management program for the two reactors. The document outlines preparations to maintain safe conditions, prevent accidents and mitigate fallout if a nuclear accident occurs.

Nuclear watchdog approves 10-year lifespan extension for Kori units 3, 4

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Summary

The Nuclear Safety and Security Commission was set to decide Tuesday in South Korea whether to allow Kori units 3 and 4 to restart and operate for an additional 10 years. The two 950-megawatt pressurized water reactors have passed their designed 40-year lifespans. If approved, Kori-3 could operate until September 2034 and Kori-4 until August 2035.

Key Facts

Kori-3 was suspended on Sept. 28, 2024, while Kori-4’s operational lifespan expired on Aug. 6, 2025.
Korea Hydro and Nuclear Power plans to seek lifespan extensions for nine aging plants.
The commission approved the accident management program for both reactors earlier this month, covering preparations to maintain safe conditions, prevent accidents and mitigate their effects.
The watchdog approved a 10-year lifespan extension for the Kori-2 lightwater reactor last year.

By Yonhap

Published Oct 27, 2026 1:57 pm KST
Updated Oct 27, 2026 5:15 pm KST

The Kori nuclear reactor units 3 and 4 on the northeastern coast of Busan / Yonhap

The country's nuclear watchdog decided Tuesday to extend the operational life of two nuclear reactors located on the country's southeastern coast by an additional 10 years.

The approval by the Nuclear Safety and Security Commission (NSSC) came four years after the Korea Hydro & Nuclear Power (KHNP), the state-run power operator, requested the agency review the restart of Kori units 3 and 4.

The two pressurized water reactors of 1,025 megawatts gross capacity had stopped power generation after 40 years of commercial use that began in 1985 and 1986, respectively. The country's nuclear watchdog had approved last year a 10-year extension for the Kori-2 light-water reactor.

The decision also came after the commission approved early this month the accident management program for the two nuclear reactors — a document that outlines preparations, including strategies to maintain safe conditions, to prevent accidents and mitigate any fallout if a nuclear accident occurs.

Accordingly, Kori-3 will be able to operate till September 2034 and Kori-4 will run until August 2035.

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