South Korea has developed one of the world’s largest and most technically mature nuclear power industries. Nuclear generation is not only a source of domestic electricity; it is also part of the country’s industrial, trade, and energy-security strategy. The sector supports reactor engineering, heavy manufacturing, construction, fuel production, plant operation, and increasingly important technology exports.
As of June 2026, South Korea had 26 commercial reactors in operation, providing roughly one-third of national electricity. Two additional APR1400 reactors were classified as under construction at the Saeul site, although Saeul 3 had already reached first criticality and entered its commissioning program. This places South Korea among the relatively small number of advanced economies that are still adding large reactors to an established nuclear fleet.
Standardized Reactors Support a Large Domestic Fleet
South Korea’s reactors are concentrated at several coastal sites, where access to cooling water and established transmission infrastructure supports large generating complexes. The principal locations include Kori and Saeul near Busan and Ulsan, Hanul and Shin Hanul on the east coast, Hanbit in the southwest, and Wolsong near Gyeongju.
Most of the fleet consists of pressurized water reactors. Several older units were developed using technology originally connected to overseas suppliers, but South Korea gradually built its own engineering, manufacturing, and operational capabilities. This process produced the OPR1000 and later the larger APR1400, which has become the flagship design of the Korean nuclear industry.
The use of standardized designs has allowed Korean companies to repeat construction processes, maintain specialized workforces, and develop a domestic supply chain around reactor vessels, steam generators, turbines, control systems, civil engineering, and maintenance services. Korea Hydro & Nuclear Power, commonly known as KHNP, operates the commercial reactor fleet, while companies such as Korea Electric Power Corporation, Doosan Enerbility, Hyundai Engineering & Construction, Samsung C&T, and numerous specialized suppliers contribute to new projects and plant servicing.
South Korea also operates three remaining pressurized heavy-water reactors at Wolsong. These units use a different technology from the country’s main pressurized water reactor fleet and form a smaller legacy segment of the national nuclear system.
Saeul and Shin Hanul Extend the APR1400 Program
The latest domestic construction has focused on the APR1400. Four reactors of this design were already operating in South Korea at Saeul units 1 and 2 and Shin Hanul units 1 and 2. Saeul units 3 and 4 were progressing through the final stages of construction and commissioning in 2026.
Saeul 3 achieved first criticality in April 2026 after receiving regulatory approval to begin reactor operations. First criticality marks the start of a controlled nuclear chain reaction, but it does not mean that a reactor has entered full commercial service. The unit must complete power-raising tests, grid synchronization, and additional safety checks before regular operation. Commercial operation was expected later in 2026, with Saeul 4 following under the broader construction schedule.
South Korea is also moving forward with Shin Hanul units 3 and 4. Their development had been suspended during the previous government’s nuclear-reduction policy, but the project was later revived. The return of these units helped restore continuity for manufacturers and engineering companies that had faced uncertainty when the domestic new-build pipeline was reduced.
The central advantage of this program is repetition. South Korea is not creating a completely new reactor model for each project. It is extending a design family that utilities, regulators, contractors, and suppliers already understand. This does not remove the risk of delays or cost increases, but it preserves knowledge that can disappear when countries go many years without constructing reactors.
The Electricity Plan Gives Nuclear a Larger Long-Term Role
South Korean nuclear policy has changed considerably between governments. An earlier strategy sought to reduce dependence on nuclear power, retire older reactors, and avoid additional construction beyond projects already underway. That policy was later reversed as energy security, industrial competitiveness, carbon reduction, and rising electricity demand gained greater political importance.
The 11th Basic Plan for Electricity Supply and Demand, finalized in February 2025, covers the national power system through 2038. It provides for two additional large reactors with a combined capacity of approximately 2.8 gigawatts and a small modular reactor program representing about 700 megawatts.
Under the plan, annual nuclear generation is expected to rise from 180.5 terawatt-hours in 2023 to approximately 248.3 terawatt-hours in 2038. Nuclear power’s share of generation would increase from 30.7% to about 35.2%. In January 2026, the government confirmed that the two planned large reactors would continue despite further political debate over the future electricity mix.
The additional capacity is intended to help meet rising demand from semiconductor manufacturing, data centers, electrified transport, advanced industry, and other power-intensive sectors. South Korea imports almost all the fossil fuels it consumes, giving nuclear power an energy-security value that extends beyond emissions reduction. Uranium must also be imported, but nuclear plants require much smaller fuel volumes than coal- or gas-fired stations and can store fuel for extended periods.
Nuclear expansion is planned alongside substantial renewable growth rather than as its replacement. South Korea’s larger power-system challenge will be coordinating high-output nuclear stations with variable solar and wind generation, storage systems, flexible demand, and modernized transmission networks.
Reactor Exports Have Become a National Industrial Objective
South Korea’s nuclear ambitions increasingly depend on overseas construction. The four-unit Barakah nuclear power plant in the United Arab Emirates established the APR1400 as an exported commercial reactor. The units entered the grid in stages between 2020 and 2024, creating a visible reference project for Korean engineering and project management.
The Barakah program demonstrated that South Korea could organize a large international consortium, construct several standardized reactors at one site, train local operators, and support a new national nuclear program. It also showed the commercial value of retaining an active domestic supply chain.
A second major export breakthrough came in June 2025, when KHNP signed an engineering, procurement, and construction contract for two new reactors at Dukovany in the Czech Republic. The planned APR1000 units adapt Korean technology to European requirements and represent a major test of whether South Korea can establish a lasting position in the European nuclear market.
The Dukovany project matters beyond the value of the contract. Successful delivery could support Korean bids in other countries considering replacement reactors, new nuclear programs, or small modular technologies. It could also strengthen demand for Korean components, engineering services, operating support, and nuclear-fuel expertise.
However, reactor exports involve more than offering a competitive construction price. Projects must meet national licensing requirements, local-content commitments, European competition rules, financing expectations, and intellectual-property agreements. South Korea’s export performance will therefore depend on its ability to combine standardized technology with country-specific regulatory and industrial conditions.
Spent Fuel Management Remains a Strategic Constraint
The continued operation and expansion of South Korea’s fleet increases the importance of spent nuclear fuel management. Used fuel is stored at reactor sites while the country develops a permanent long-term system. Storage capacity at some locations has become a growing policy concern, particularly because finding communities willing to host interim or permanent facilities is politically difficult.
National planning provides for interim storage followed by disposal in a deep geological repository. Reaching that point requires legislation, site evaluation, public consultation, technical research, and long-term institutional commitment. The timetable for developing permanent facilities is much longer than the construction period for a new reactor.
This issue does not immediately prevent South Korea from operating its fleet, but it affects the credibility of a long-term expansion policy. A country that sells nuclear technology internationally must also demonstrate that it can manage fuel, waste, decommissioning, and environmental obligations across the complete reactor life cycle.
South Korea Is Building Around Continuity
South Korea’s nuclear advantage comes from continuity across engineering, manufacturing, construction, and operation. The country has maintained a large reactor fleet, developed standardized designs, preserved specialized suppliers, and completed an overseas multi-reactor project.
The next phase will test whether this model can remain stable through domestic political changes. Saeul 3 and 4, Shin Hanul 3 and 4, the two additional large reactors planned for the 2030s, and the proposed small modular reactor program create a substantial development pipeline. At the same time, lifetime extensions, spent-fuel storage, grid flexibility, and project finance will require sustained attention.
If South Korea can complete its domestic projects while delivering the Dukovany reactors successfully, nuclear energy will remain both a major part of its electricity system and one of its most important high-value infrastructure exports.
