South Korea - World Nuclear Outlook Report
Current operations
South Korea has 26 operable reactors, generating about 29% of the country's electricity. Four APR1400 reactors are under construction: Saeul 3&4 and Shin Hanul 3&4.
Saeul 3 reached first criticality on 12 April 2026, but commissioning tests were halted by an automatic shutdown in August (attributed by the NSSC to operator error) and a manual shutdown in September after a turbine-side steam leak. KHNP had been aiming for commercial operation in October 2026. Saeul 4 is awaiting an operating licence from the NSSC, with a decision expected in December 2026.
Construction of Shin Hanul 3 and 4 began in May 2025 and May 2026, with completion expected in 2032 and 2033, respectively.
South Korea is seeking lifetime extensions for ten units. Kori 2 (operating since 1983) was approved in November 2025 to operate until April 2033. Kori 3 and 4 and Hanbit 1 and 2 have been suspended since their initial licences expired; in September 2026 the NSSC began deliberating on their accident management plans and operating licence amendments. KHNP is submitting safety assessment reports for the remaining units, Hanul 1 and 2 and Wolsong 2-4.
Table Kr.1 Nuclear capacity status (as of 1 October 2026)
| Operable reactors | Operable reactors net capacity (MWe) | Operable reactors gross capacity (MWe) | Reactors under construction | Reactors under construction gross capacity (MWe) | Cumulative carbon dioxide emissions avoided 1970-2025 (cf. coal) (MtCO2) |
|---|---|---|---|---|---|
| 26 | 25,609 | 27,099 | 4 | 5600 | 2180 |
Nuclear policy and outlook
The 11th Basic Plan for Electricity Supply and Demand (2024-2038), finalized in February 2025, states that nuclear energy would provide 31.8% of electricity by 2030 and 35.6% by 2038. It raises nuclear capacity from 24.7 GWe in 2023 to 28.9 GWe in 2030 and 35.2 GWe in 2038, and includes the construction of two additional large reactors (in addition to Saeul 3&4 and Shin Hanul 3&4), as well as 700 MWe of SMR capacity by 2038.
President Lee Jae-myung, who took office in June 2025, reiterated in September 2025 that South Korea’s long-term direction “must be toward renewable energy”, while stressing that existing and under-construction nuclear projects would continue. In January 2026, following surveys showing strong public support for nuclear energy, the government confirmed it would proceed with the two new large reactors in the 11th Basic Plan.
In January 2026 KHNP launched a bidding process for a site for the two new reactors, and in June it selected Yeongdeok in North Gyeongsang province as the candidate site. Gijang, in Busan, was selected to host an SMR.
Since October 2025 the Ministry of Climate, Energy and Environment (MCEE) has been responsible for energy policy and nuclear plant construction and operation, taking over from the Ministry of Trade, Industry and Energy. In September 2026 the MCEE began a three-month public deliberation on nuclear power’s role in the 12th Basic Plan (2026-2040).
Table Kr.2 Contributions to total capacity projection in 2050 (gross)
| 60 year operation (MWe) | 80 year operation (MWe) | Currently under construction capacity (MWe) | Planned capacity (MWe) | Proposed capacity (MWe) | Potential capacity (MWe) | Government capacity target (MWe) | Additional capacity* required to meet government target (MWe) | Total capacity (MWe) |
|---|---|---|---|---|---|---|---|---|
| 20,252 | 6847 | 5600 | - | - | 3500 | - | - | 39,699 |
| *Capacity additional to operable, under construction, planned, proposed and potential capacities required to meet the government target. | ||||||||
Readiness Assessment
South Korea has one of the world’s most mature nuclear programmes, with a full-scope domestic industry, four APR1400 units under construction and candidate sites selected for two further large reactors and an SMR. However, government support for nuclear energy has wavered in recent years. The current government has reconfirmed the additional reactors, but the direction beyond 2038 will be shaped by the forthcoming 12th Basic Plan.
| Country Category | Pacesetter |
|---|---|
| Policy Framework Readiness | High The 11th Basic Plan provides a quantified 2038 pathway. The current government reconfirmed the two additional large reactors in January 2026, and candidate sites have been selected for large reactors and an SMR. |
| Institutional & Infrastructure Readiness | High
South Korea has an experienced regulator, a highly capable state-owned utility and operator, and an extensive domestic nuclear supply chain. Spent fuel, however, is still held in storage at reactor sites that is nearing capacity, and a 2025 law has only recently set out the framework for finding sites for interim storage and final disposal. |
| Programme & Project Development Readiness | Moderate-High Four reactors are under construction, one of which (Saeul 3) is undergoing commissioning. Candidate sites have been selected for another two large reactors and an SMR. |
| Target Achievability | High The 35.2 GWe 2038 pathway is credible, but depends on long-term operation approvals, first-of-a-kind SMR delivery and the new Yeongdeok reactors entering service on schedule. While achievable, South Korea’s target involves limited new build, in comparison to the size of its current reactor capacity. |
