South Korea: construction delays for units 3 and 4 of Saeul NPP

The construction period of units 3 and 4 of South Korea’s Saeul Nuclear Power Plant (NPP) has been extended from 134 months, starting in September 2014, to 147 months, pushing back the deadline for completion to November 2026. The extension was announced by the Ministry of Trade, Industry & Energy, which said more time was needed to meet the updated standards for nuclear accident management. Saeul units 3 and 4 are the first nuclear facilities to which strengthened regulations, developed after the Fukushima nuclear accident and the Gyeongju earthquake, are applied. This is delaying the approval of their accident management plan by the Nuclear Safety and Security Commission.
The accident management plan was introduced in 2015 following the Fukushima accident. It covers the scope, strategies, implementation systems, evaluation, and training plans for managing not only facility failures at nuclear plants but also external disasters and various major accidents. It also includes disaster response measures for neighbouring areas. Construction works at the Saeul NPP have already been affected by several delays in the past. In 2017, they were temporarily halted for three months for a public consultation after the South Korean government decided to phase out nuclear energy. In 2018, the project timeline was affected again by the introduction of the 52-hour workweek system. In 2021 and 2022, changes to seismic design standards after the Gyeongju earthquake and the introduction of new wastewater treatment facility designs caused further extensions of the original construction deadline. Korea Hydro & Nuclear Power (KHNP) now expects unit 3 to be completed in February 2026 and unit 4 in November 2026. As of the end of March 2025, the construction progress for both units stood at 96.34%.