South Korean energy and materials company SK Innovation Co has sold part of its stake in US TerraPower to Korea Hydro & Nuclear Power (KHNP), strengthening a three-way partnership intended to expand into the global SMR market. SK Innovation is a conglomerate that serves as an intermediate holding company for the SK Group, historically focused on oil and gas. Following its major merger with SK E&S in November 2024, it became the largest private energy company in the Asia-Pacific region. The company operates through specialised subsidiaries across several key industries.
This is the first time a Korean public energy company has directly invested in a SMR developer, SK Innovation said in a press release. In August 2022, SK Innovation and SK Corp jointly invested KRW350bn ($250m) in TerraPower, becoming the company’s second-largest shareholder. SK Innovation said its position as the second-largest shareholder will remain unchanged following the partial transfer of its stake to KHNP. SK Innovation is seeking to deliver integrated energy solutions to address power supply challenges for the fast-growing AI industry.
Terrapower’s Natrium technology features a 345 MWe sodium-cooled fast reactor with a molten salt-based energy storage system. The storage technology can boost the system’s output to 500 MWe of power when needed as it is designed to keep base output steady, ensuring constant reliability and can quickly ramp up when demand peaks. TerraPower says the decoupled design separates major structures into two independent islands – nuclear and energy, which significantly reduces the quantity of specialised materials, cutting plant costs and accelerating construction timelines.
TerraPower broke ground on its Natrium project in 2024 at its site in Kemmerer in Wyoming and work is underway of construction of the non-nuclear parts of the plant. TerraPower is building its first plant through a public-private partnership with the US Department of Energy’s (DOE) Advanced Reactor Demonstration Program (ARDP), which authorises a 50/50 cost share and up to $2bn for the Natrium project.
“KHNP’s investment in TerraPower strengthens our three-way collaboration in the global SMR business,” said Kim Moo-hwan, Executive Vice President and Director of SK Innovation’s Energy Solution Business Division. “SK Innovation will work closely with KHNP to support the Wyoming project, pursue overseas SMR opportunities and achieve innovative outcomes, including the localization of key materials and components.”
The three companies began their cooperation in April 2023 by signing a Memorandum of Understanding (MOU) for ‘SMR development and demonstration’ to expand the global SMR supply chain. Following KHNP’s investment, the partners plan to pursue additional SMR construction projects in the US and overseas, as well as finalise a business agreement for SMR deployment in Korea.
KHNP completed the review process by the US Committee on Foreign Investment (CFIUS) in December 2025, establishing a regulatory foundation for its entry into the global SMR market. SK Innovation aims to combine its expertise in energy and materials with KHNP’s expertise in nuclear power plant construction and operation. Together, they plan to establish SMR ecosystems for data centres and other industrial sites in Korea and overseas, and deliver customised integrated energy solutions to address power supply challenges.
TerraPower CEO Chris Levesque noted: “TerraPower has built strong relationships with multiple Korean companies across the nuclear energy supply chain…. We are proud to welcome KHNP to our group of investors, continuing our years of strategic collaboration with SK and KHNP.”
Park In-sik, Executive Vice President and Head of the Export Business Division at KHNP, said, “This investment is a major milestone for KHNP in securing global leadership in next-generation nuclear energy. By combining our 50 years of experience in nuclear plant construction and operation with SK Innovation’s competitiveness in energy and TerraPower’s technology, we will play a leading role in expanding the SMR market. The three companies plan to sign definitive commercialisation agreements within the first half of this year to establish a foundation for global SMR projects in North America and beyond.”
