South Korea’s nuclear industry is moving deeper into TerraPower’s commercial strategy just as the U.S. developer crosses the most important threshold yet for its Natrium advanced reactor: construction.
TerraPower’s 345 MW Natrium reactor in Wyoming received a U.S. Nuclear Regulatory Commission construction permit in March 2026, the first NRC construction permit for a commercial non light water reactor. Construction officially began in April, shifting the project from licensing and engineering into the much more demanding phase of building a first of a kind plant.
That transition is giving Korean companies a more concrete role in TerraPower’s development pipeline. During Bill Gates’ August visit to South Korea, SK Innovation and TerraPower signed a preliminary agreement covering cooperation on global SMR projects, while HD Hyundai and Doosan Enerbility are positioning themselves across reactor manufacturing and component supply.
The significance extends beyond another corporate partnership. TerraPower now needs to establish a repeatable industrial supply chain around a reactor design that has not yet operated commercially. South Korea, with decades of experience manufacturing nuclear equipment and delivering conventional reactors, is offering precisely the industrial capability TerraPower will need if Natrium is to progress from a single demonstration project toward a broader fleet.
SK Moves From Investor to Potential Global Partner
SK’s relationship with TerraPower is not new. SK Inc. and SK Innovation collectively invested $250 million in TerraPower during a 2022 funding round. In 2023, SK, Korea Hydro & Nuclear Power and TerraPower also signed a strategic collaboration agreement covering demonstration and commercialization of the Natrium technology.
The latest agreement changes the commercial context. SK Innovation and TerraPower are establishing the terms for a potential global joint business focused on SMR projects in the United States and other markets, according to South Korea’s Industry Ministry and Reuters. Financial details were not disclosed.
For SK, the attraction is access to an emerging advanced nuclear market without having to develop its own reactor technology. For TerraPower, the partnership potentially provides access to Korean project development, manufacturing and financing capabilities.
That distinction matters because the next challenge for Natrium is not proving that an advanced reactor can be designed. It is proving that the technology can be manufactured, constructed and replicated at a commercially acceptable cost and schedule.
HD Hyundai is positioned further downstream in the supply chain. TerraPower awarded the company a contract to manufacture the reactor vessel for the first Natrium plant, alongside other international suppliers responsible for major reactor enclosure components. TerraPower announced in December 2024 that HD Hyundai would manufacture the reactor vessel, while Doosan Enerbility would supply the core barrel, guard vessel and internal supports.
The relationship is now moving toward potential production at greater scale. HD Hyundai has discussed developing manufacturing capacity capable of producing two to three reactor vessels annually as the technology moves toward commercialization.
That capacity would be significant if TerraPower can secure multiple follow on projects, but it also exposes one of the central uncertainties surrounding the SMR sector. Manufacturing scale only creates economic value if reactor orders materialize. A factory designed around a single first of a kind project carries a very different risk profile from a production line backed by a standardized fleet program.
The Korean industrial model is nevertheless potentially important. TerraPower supplies the reactor design, while Korean companies can provide heavy manufacturing, engineering and construction capabilities. If that division of labor works on the Wyoming project, it could become a template for subsequent international deployments.
Doosan Enerbility provides another indication that TerraPower’s Korean partnerships are progressing beyond strategic discussions. The Korean company initially signed a December 2024 agreement with TerraPower covering manufacturability reviews and design support for three major Natrium components: the reactor guard vessel, reactor support structure and core barrel structure.
The subsequent move toward actual component manufacturing is more commercially significant than the earlier engineering agreement. It requires the design to be translated into manufacturing specifications, quality requirements and nuclear supply chain processes.
That experience could become valuable beyond Natrium. Advanced reactor developers face a shortage of qualified suppliers capable of manufacturing specialized nuclear components to the required standards. Companies that successfully qualify for a first project can potentially establish themselves within subsequent reactor supply chains.
But qualification is not the same as volume. The commercial value for Doosan, HD Hyundai and other Korean suppliers will ultimately depend on whether TerraPower can generate a pipeline of additional Natrium projects.
Natrium Has Reached the Point Where Execution Matters
The NRC issued TerraPower’s construction permit for Kemmerer Unit 1 on March 9, 2026. The project is designed around a 345 MW sodium cooled fast reactor coupled with a molten salt energy storage system that can increase the plant’s electrical output to as much as 500 MW when required.
The NRC describes the reactor as a pool type sodium fast reactor with an 840 MW thermal power level. The plant will use metallic uranium zirconium fuel containing high assay low enriched uranium, or HALEU.
The construction permit was preceded by an NRC safety review completed in December 2025. TerraPower subsequently commenced formal construction in April 2026 following years of site preparation and non nuclear construction activities.
First of a kind nuclear projects have to demonstrate not only technical performance but also the ability to manage construction complexity, regulatory requirements, nuclear quality assurance, specialized materials and fuel availability. TerraPower must establish that its technology can move through these stages without the cost and schedule escalation that has affected several large nuclear projects. The company expects the Kemmerer project to be completed around 2030.
The involvement of Korean companies is particularly relevant because South Korea has an established nuclear industrial base covering reactor components, engineering, procurement and construction.
That capability does not remove the risks associated with a new reactor design, but it can reduce the distance between engineering specifications and industrial production. TerraPower already selected HD Hyundai and Doosan Enerbility for major components before the construction permit was issued, indicating that supply chain development has been integrated into the project rather than treated as a later requirement.
For South Korea, the opportunity is broader than supplying one American reactor. The country has been seeking a role in the international SMR market as governments and utilities examine smaller and advanced nuclear systems for industrial power, grid reliability and potentially data center demand.
The commercial opportunity, however, depends on whether SMRs become a repeatable product rather than a collection of one off demonstration projects.
This is particularly important for suppliers considering dedicated manufacturing capacity. A production facility capable of turning out two or three reactor vessels annually requires sustained demand to justify its capital requirements. That demand does not exist simply because more than 100 SMR concepts are being developed globally. Only projects with financing, regulatory pathways, customers and credible construction schedules can create firm equipment orders.
AI Demand Is Strengthening the Case, Not Removing the Risk
The rapidly increasing electricity requirements associated with data centers and artificial intelligence are strengthening interest in nuclear power because these facilities require reliable electricity around the clock.
For advanced nuclear developers, this creates a potentially attractive market. A reactor capable of supplying firm power while integrating storage could offer a different proposition from intermittent renewable generation, particularly in regions where grid capacity is becoming constrained.
But the existence of demand does not guarantee that an SMR can compete economically. Data center developers and utilities still have to compare nuclear projects with natural gas generation, renewable power combined with storage, conventional nuclear and grid procurement.
The strongest commercial case for Natrium will therefore emerge only if TerraPower can demonstrate that its technology can be delivered repeatedly with predictable costs and schedules.
TerraPower’s progress has changed the nature of the opportunity for Korean industry. Before the NRC permit, much of the relationship centered on investment, technology cooperation and manufacturability. Now major Korean companies are participating in the physical supply chain for a reactor that is actually under construction.
The first commercial deployment will establish whether the claimed benefits of standardized manufacturing and repeat construction can be translated into actual project economics. If Natrium progresses successfully, Korean suppliers could gain reference experience that strengthens their position in future TerraPower projects and potentially other advanced reactor programs.
If construction encounters significant cost, schedule or supply chain problems, however, the same project will demonstrate why the transition from reactor concept to commercial fleet is considerably harder than accumulating strategic partnerships.
For now, South Korea is positioning itself at several points in TerraPower’s value chain. SK Innovation is pursuing a broader global business relationship, HD Hyundai is supplying the reactor vessel and developing potential manufacturing capacity, while Doosan Enerbility is producing critical reactor components.
