Nuclear Power Renaissance — South Korea's 28 Reactors, APR-1400 Exports, and SMR Development

The Nuclear Foundation of Korean Energy Security

South Korea’s nuclear power program stands as one of the most consequential energy infrastructure achievements of the past half century. The country operates 28 commercial nuclear reactors across four major sites — Kori, Hanbit, Hanul, and Wolsong — with a combined installed capacity exceeding 26.4 gigawatts. Nuclear generation provides approximately 31 percent of total electricity output, making it the single largest source of carbon-free power in the national grid. This fleet positions Korea as the world’s fifth-largest nuclear power producer by installed capacity, behind the United States, France, China, and Russia.

The strategic significance of nuclear energy in Korea’s context cannot be overstated. As a nation importing nearly 90 percent of its primary energy — with no domestic reserves of oil, natural gas, or coal — nuclear power represents the only large-scale, dispatchable, low-carbon electricity source that Korea can operate with domestically manufactured fuel assemblies and reactor components. Every kilowatt-hour generated by nuclear displaces imported fossil fuel, reducing both carbon emissions and the structural vulnerability that energy import dependence creates. The 2022 energy price shock following Russia’s invasion of Ukraine, which sent Korean energy import costs surging by tens of billions of dollars, reinforced the economic case for maximizing nuclear output.

Korea’s nuclear journey began in 1978 with the commissioning of Kori Unit 1, a 587-megawatt Westinghouse pressurized water reactor. The early decades relied on imported reactor designs and foreign technical assistance, but Korea pursued an aggressive technology transfer and localization strategy that transformed the country from a technology recipient into a reactor designer and exporter within three decades. By the late 1990s, Korean firms had developed the capability to design, construct, and operate nuclear power plants with over 95 percent domestic content. This progression from imported technology to export-ready indigenous design represents one of the most successful industrial technology absorption programs in the energy sector globally.

The APR-1400: Korea’s Export Flagship

The Advanced Power Reactor 1400, designated APR-1400, emerged from Korea’s reactor development program as a Generation III+ pressurized water reactor design with 1,400 megawatts of electrical output. Developed by Korea Hydro and Nuclear Power in collaboration with Korea Electric Power Corporation (KEPCO) and its engineering subsidiary KEPCO Engineering and Construction, the APR-1400 incorporates passive and active safety systems that exceed post-Fukushima international regulatory requirements. The design received certification from the United States Nuclear Regulatory Commission in 2019, validating its safety case against the most stringent Western regulatory standards.

The domestic deployment of APR-1400 technology began with Shin-Kori Units 3 and 4, which entered commercial operation in 2016 and 2019 respectively. Shin-Hanul Units 1 and 2 followed, with Unit 1 achieving commercial operation in 2022 and Unit 2 completing fuel loading for commissioning in 2024. These units demonstrate construction timelines of approximately six to seven years from first concrete to commercial operation — competitive with the best international benchmarks and substantially faster than the decade-plus timelines that have plagued nuclear construction projects in the United States and Europe.

The APR-1400’s international breakthrough came with the December 2009 contract to build four reactors at Barakah in the United Arab Emirates. The 20-billion-dollar contract, won by a KEPCO-led consortium against competition from French, American, and Japanese bidders, marked Korea’s entry into the nuclear export market. All four Barakah units have achieved commercial operation between 2021 and 2024, collectively providing approximately 25 percent of the UAE’s electricity generation. The Barakah project demonstrated Korean construction capability on foreign soil, with on-time and on-budget delivery that contrasted sharply with the cost overruns and schedule delays affecting contemporary nuclear projects in Finland, France, and the United Kingdom.

Building on the Barakah success, KEPCO has pursued additional export opportunities. Negotiations with Poland for the construction of six APR-1400 units at the Patnow site advanced to a preliminary agreement in 2024, with final investment decisions expected by 2026. The Czech Republic shortlisted the APR-1400 alongside the French EPR for its Dukovany expansion project, though the decision ultimately favored the Korean bid in 2024. Romania, Saudi Arabia, and Egypt have also engaged in discussions about potential APR-1400 deployment. The cumulative value of Korea’s nuclear export pipeline, including reactor construction, fuel supply, maintenance, and training contracts, could exceed 100 billion dollars over the next two decades if current negotiations convert to binding agreements.

The 11th Basic Plan and Nuclear’s Central Role

The 11th Basic Plan for Electricity Supply and Demand, covering the period 2024 to 2038, elevated nuclear power to the centerpiece of Korea’s energy transition strategy. The plan targets a carbon-free energy share of 70 percent of total generation by 2038, with nuclear providing the majority of that share. This represented a decisive reversal of the previous Moon Jae-in administration’s policy, which had targeted a gradual nuclear phaseout with no new reactor construction and a planned reduction of nuclear’s share to below 24 percent by 2030.

Under the current framework, the government has approved the continued construction of Shin-Hanul Units 3 and 4, which had been suspended under the previous policy. These 1,400-megawatt APR-1400 units are expected to enter commercial operation in the early 2030s. Life extensions for existing reactors have been authorized, with Kori Unit 2, originally scheduled for retirement, receiving a 10-year operating license extension. The Wolsong Unit 1 early closure decision, which had been a flashpoint of political controversy, is now viewed as a cautionary example of premature reactor retirement.

The financial logic supporting nuclear expansion is grounded in levelized cost comparisons. Korea’s nuclear fleet operates at capacity factors averaging 85 to 90 percent, with a levelized cost of electricity estimated between 50 and 65 dollars per megawatt-hour for new APR-1400 construction — competitive with natural gas combined cycle generation and substantially below offshore wind when firming and grid integration costs are included. The baseload characteristics of nuclear generation — steady output regardless of weather, time of day, or season — provide grid stability that intermittent renewable sources cannot match without expensive battery storage or backup generation capacity.

The plan also positions nuclear as essential for meeting Korea’s industrial electricity demand. The semiconductor fabrication facilities operated by Samsung Electronics and SK hynix, the battery manufacturing plants of LG Energy Solution and Samsung SDI, and the data center buildout driven by artificial intelligence compute demand all require reliable, high-quality electricity supply with minimal frequency variation. Nuclear generation, with its ability to operate at constant output for 18 to 24-month fuel cycles, provides the grid backbone that supports these precision industrial loads.

Small Modular Reactor Development

Korea’s nuclear ambitions extend beyond conventional large reactors into the emerging field of small modular reactors. The Korea Atomic Energy Research Institute has been developing the SMART (System-integrated Modular Advanced ReacTor) design since the 1990s, achieving standard design approval from the Korean Nuclear Safety and Security Commission in 2012. SMART is a 100-megawatt integral pressurized water reactor designed for deployment in configurations of one to four modules, targeting markets that cannot absorb the 1,400-megawatt output of an APR-1400.

The SMART reactor’s design integrates the steam generator within the reactor pressure vessel, eliminating large-bore primary coolant piping and reducing the potential for large-break loss-of-coolant accidents. The reactor incorporates passive safety systems that can maintain core cooling for 72 hours without external power or operator intervention, addressing a key lesson from the Fukushima Daiichi accident. The compact footprint — approximately one-tenth the site area of a conventional large reactor — enables deployment in locations where land availability or grid capacity constraints preclude larger installations.

Saudi Arabia signed a cooperation agreement with Korea in 2015 for the construction of two SMART units, though the project timeline has experienced delays due to financing negotiations and site selection processes. The potential market for small modular reactors extends beyond electricity generation to include desalination, district heating, and industrial process heat — applications particularly relevant to Middle Eastern and Southeast Asian markets where Korea’s nuclear industry seeks to establish a commercial presence.

Beyond SMART, Korean research institutions are pursuing next-generation reactor concepts. The sodium-cooled fast reactor program at KAERI has operated the experimental HANARO reactor since 1995 and is developing designs for a prototype Generation IV fast reactor. Molten salt reactor research, funded through the National Research Foundation, investigates thorium fuel cycles and actinide burning for nuclear waste reduction. These advanced concepts target deployment timelines in the 2040s, positioning Korea to participate in the next wave of nuclear technology commercialization.

Private sector involvement in Korean SMR development has accelerated since 2022. Doosan Enerbility, the primary manufacturer of nuclear reactor components, has partnered with NuScale Power for potential deployment of NuScale’s VOYGR design in Korean and export markets. Samsung Heavy Industries and HD Hyundai have explored floating nuclear power plant concepts that would combine Korean shipbuilding expertise with nuclear engineering capability, targeting remote island communities and offshore industrial facilities.

Nuclear Safety and Regulatory Framework

Korea’s nuclear safety regime operates under the Nuclear Safety and Security Commission, an independent regulatory body established in 2011 following the Fukushima accident. The commission operates separately from the Ministry of Trade, Industry and Energy, which handles energy policy and promotion, maintaining the institutional separation between nuclear promotion and safety regulation that international best practice demands. Korea participates in the International Atomic Energy Agency’s peer review programs, including the Integrated Regulatory Review Service, which evaluates the effectiveness and independence of national nuclear regulatory bodies.

The post-Fukushima safety upgrades implemented across Korea’s nuclear fleet included the installation of additional passive cooling systems, emergency diesel generators positioned above potential flood levels, severe accident management guidelines, and hydrogen recombiners to prevent explosive hydrogen accumulation during beyond-design-basis accidents. These modifications, completed across all 28 operating units by 2017, represented an investment of approximately 1 trillion KRW.

Seismic safety received heightened attention following the 2016 Gyeongju earthquake, the largest recorded seismic event in Korean history at magnitude 5.8. The proximity of the earthquake’s epicenter to the Wolsong nuclear complex triggered comprehensive reassessment of seismic hazard analyses for all Korean nuclear sites. Updated probabilistic seismic hazard assessments, incorporating newly identified fault systems and revised ground motion prediction models, confirmed that existing plants met safety margins but led to enhanced seismic monitoring networks and revised emergency procedures.

Spent fuel management remains the most unresolved challenge in Korea’s nuclear program. Korean reactors have accumulated approximately 30,000 metric tons of spent nuclear fuel, stored in cooling pools at reactor sites. Pool storage capacity at several sites is approaching saturation, with Kori and Hanbit projected to exhaust available space within the next decade without intervention. Korea has not identified a permanent geological disposal site, and public opposition to both interim storage facilities and final repositories has prevented political resolution of the issue. Dry cask storage expansion at existing sites provides a medium-term solution, but the long-term waste management question requires political decisions that no administration has been willing to make.

Nuclear Power and Carbon Neutrality

The intersection of nuclear power with Korea’s 2050 carbon neutrality target defines the strategic rationale for the nuclear renaissance. Korea’s nationally determined contribution under the Paris Agreement commits to a 40 percent reduction in greenhouse gas emissions from 2018 levels by 2030. Achieving this target requires rapid decarbonization of the electricity sector, which accounts for approximately 35 percent of national emissions.

Nuclear power’s carbon intensity — approximately 12 grams of CO2-equivalent per kilowatt-hour on a lifecycle basis, comparable to wind and lower than solar when manufacturing and installation are included — makes it the lowest-carbon firm power source available at scale. Replacing Korea’s remaining coal fleet with a combination of nuclear and renewable energy would eliminate the single largest source of power sector emissions. The 11th Basic Plan’s coal phasedown schedule, targeting 28 plant closures by 2036 and complete coal exit by 2050, implicitly depends on nuclear capacity additions to maintain grid reliability during the transition.

The Green New Deal’s emphasis on hydrogen economy development creates additional demand for nuclear generation. Green hydrogen production through electrolysis requires large quantities of electricity, and nuclear-powered hydrogen production — sometimes called pink or purple hydrogen — offers a pathway to produce hydrogen at scale without the intermittency challenges of renewable-powered electrolysis. Korea’s hydrogen economy strategy, targeting 300,000 fuel cell vehicles and 660 hydrogen charging stations by 2030, will require substantial electricity input that nuclear generation could provide.

Workforce and Supply Chain

Korea’s nuclear industry employs approximately 35,000 workers directly, with indirect employment across the supply chain supporting an additional estimated 100,000 jobs. The nuclear workforce spans reactor operation and maintenance at KHNP, engineering design and construction management at KEPCO E&C, component manufacturing at Doosan Enerbility, fuel fabrication at KEPCO Nuclear Fuel, and research at the Korea Atomic Energy Research Institute.

The APR-1400 export program has created a new dimension of employment in overseas project management, construction supervision, and training. The Barakah project in the UAE deployed thousands of Korean engineers and technicians over its decade-long construction period, and ongoing operations support contracts provide sustained employment. Potential new export projects in Poland, Czech Republic, and elsewhere would generate additional demand for Korea’s nuclear workforce.

The domestic supply chain for nuclear components is one of the most vertically integrated in the world. Doosan Enerbility manufactures reactor pressure vessels, steam generators, pressurizers, and primary coolant pumps at its Changwon facility — the largest nuclear forgings plant globally. The company’s capability to produce ultra-large forgings, including one-piece reactor vessel shells weighing over 500 tons, provides a competitive advantage in nuclear construction where manufacturing bottlenecks at forging facilities have historically constrained global build rates.

Public Opinion and Political Dynamics

Nuclear energy policy in Korea remains subject to significant political oscillation. The progressive Moon Jae-in administration (2017-2022) pursued nuclear phase-out, halting new construction and imposing a moratorium on reactor life extensions. The conservative Yoon Suk-yeol administration (2022-2027) reversed course decisively, embracing nuclear expansion as central to both energy security and export competitiveness. This political cycling creates uncertainty for long-term investment decisions, as reactor construction timelines of six to eight years span multiple presidential terms.

Public opinion surveys consistently show that Korean citizens are divided on nuclear power, with support levels typically ranging between 45 and 55 percent depending on framing and current events. The proximity of nuclear facilities to population centers, seismic risk awareness following the Gyeongju earthquake, and the unresolved spent fuel storage question fuel opposition. Conversely, concerns about energy security, electricity prices, and climate change drive support, particularly among younger demographics who view nuclear as necessary for decarbonization.

The political economy of nuclear power intersects with Korea’s industrial conglomerate structure. Doosan Group, Hyundai Engineering, Samsung Engineering, and other chaebol maintain substantial business interests in nuclear construction and component supply. The alignment of industrial lobbying power with the current administration’s pro-nuclear policy creates a policy environment favorable to continued expansion, though the potential for reversal under a future progressive administration remains a risk factor for long-term planning.

Integration with Smart Grid and Energy Storage

Seoul’s smart city infrastructure provides the grid management capability needed to integrate nuclear baseload generation with variable renewable sources. The Korea Electric Power Corporation operates one of the world’s most advanced grid management systems, capable of balancing supply and demand across nuclear, thermal, and renewable generation sources in real time. Nuclear plants typically operate in baseload mode at constant output, while gas-fired plants and pumped-storage hydroelectric facilities provide load-following capability.

The expansion of battery energy storage systems across Korea — driven by the domestic battery manufacturing industry and supported by the Green New Deal investment program — creates new possibilities for nuclear-renewable integration. Excess nuclear generation during low-demand periods can charge battery systems that discharge during peak hours, improving the utilization factor of nuclear plants while reducing the need for gas-fired peaking generation.

Korea’s investment in grid infrastructure includes a 765-kilovolt ultra-high-voltage transmission backbone connecting nuclear generation centers on the coast with the Seoul metropolitan demand center. The transmission system’s capacity and reliability are critical to delivering nuclear power from remote generation sites to the concentrated load center of the capital region, where over half the national population resides and the majority of commercial and industrial electricity demand is located.

The Export Imperative

For Korea’s nuclear industry, export success is not merely a commercial opportunity but an industrial survival strategy. The domestic market for new reactor construction, while revived under current policy, cannot sustain the full manufacturing and engineering capacity that the industry maintains. Without a pipeline of export projects, the specialized workforce and supply chain capabilities developed over four decades would atrophy, undermining both domestic operations and future competitiveness.

The global nuclear renaissance, driven by climate concerns and energy security imperatives following the Ukraine conflict, has created a window of opportunity that Korea is positioned to exploit. The International Energy Agency’s Net Zero Emissions scenario calls for a doubling of global nuclear capacity by 2050, implying construction of hundreds of new reactors worldwide. Korea’s competitive advantages — demonstrated construction capability, competitive pricing, strong safety record, and NRC-certified design — position it among a small number of credible reactor suppliers alongside France’s EDF, the United States’ Westinghouse, and China’s CGN and CNNC.

The competition with China deserves particular attention. China’s nuclear construction program — with over 20 reactors under construction simultaneously — has developed scale economics and construction efficiencies that challenge Korean pricing. Chinese reactor exports, supported by state financing on favorable terms, have targeted markets in Pakistan, Argentina, and the United Kingdom. Korea’s differentiation strategy emphasizes regulatory acceptance in Western markets, where Chinese designs face greater scrutiny, and the quality track record established at Barakah.

The nuclear power renaissance in Korea represents more than energy policy — it is an expression of industrial capability, technological ambition, and strategic positioning in a decarbonizing global economy. The 28 reactors currently operating, the APR-1400 units under construction and export, and the SMR development pipeline collectively constitute one of the world’s most comprehensive nuclear energy programs. Whether Korea can sustain the political consensus needed to realize the 11th Basic Plan’s nuclear targets will determine not only the country’s path to carbon neutrality but also the future of its nuclear export industry in the global clean energy transition.