In May 2022, SK Group signed a memorandum of understanding with TerraPower to jointly develop “next-generational technologies” needed for small modular reactors (SMRs). In the August of that year, SK Inc and SK Innovation – both affiliates of SK Group, Korea’s second-largest conglomerate – announced they had invested USD250 million in TerraPower, becoming the company’s second-largest shareholder. SK Inc is a holding company of SK Group with specialisation in investment activities. Its strategic investment areas include advanced materials, biopharmaceutical, green energy and digital technologies. SK Innovation is an SK Group intermediate holding company in energy, petrochemical, lubricants, exploration and production, e-mobility battery, information and electronic materials businesses along with eight major subsidiaries.
TerraPower announced in April 2023 that it had signed a collaboration agreement with SK and Korea Hydro & Nuclear Power (KHNP) supporting the demonstration and commercialisation of its Natrium reactor and integrated energy system.
SK Innovation has now announced that it has transferred part of its stake in TerraPower to KHNP, “strengthening the three-way partnership to advance the global SMR market”. It added: “This marks the first time a Korean public energy enterprise has directly invested in a world-leading SMR developer.”
“SK Innovation aims to combine its global competitiveness in energy and materials with KHNP’s world-class expertise in nuclear power plant construction and operation,” the company said. “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 the power supply challenges of the AI era.”
KHNP and TerraPower successfully completed the US Committee on Foreign Investment review process in December 2025, “establishing a regulatory foundation for its entry into the global SMR market”.
“KHNP joins TerraPower’s current investors in supporting the first Natrium plant being built in Wyoming, along with the company’s plans to rapidly deploy additional units in the US and abroad,” TerraPower said. “This investment will accelerate ongoing efforts to explore both South Korean and other opportunities.”
TerraPower’s Natrium technology features a 345 MWe sodium-cooled fast reactor with a molten salt-based energy storage system. The storage technology can temporarily boost the system’s output to 500 MWe when needed, enabling the plant to follow daily electric load changes and integrate seamlessly with fluctuating renewable resources. TerraPower began non-nuclear construction for its first Natrium plant, in Kemmerer, Wyoming, in June 2024, and expects construction of the plant – which it says will be the first commercial-scale, advanced nuclear project in the USA – to be complete in 2030. The first Natrium project is being developed through the US Department of Energy’s Advanced Reactor Demonstration Program. The Natrium reactor is a TerraPower and GE Vernova Hitachi Nuclear Energy technology.
“We have strong relationships with multiple Korean entities across the nuclear energy supply chain, and today’s announcement is one more step to realising the Natrium technology’s promise to deliver next generation nuclear power not just in the United States, but around the world,” said TerraPower President and CEO Chris Levesque. “TerraPower, SK and KHNP have been advancing our strategic collaboration for years, and I’m proud to add KHNP to our committed investor base.”
Park In-sik, Executive Vice President and Head of the Export Business Division at KHNP, added: “This investment is a major milestone for KHNP in supporting the global deployment of 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 advanced nuclear market. The three companies plan to sign definitive commercialisation agreements this year to establish a foundation for global projects.”
“KHNP’s investment in TerraPower solidifies our three-way collaboration in the global advanced nuclear business,” said Moohwan Kim, Executive Vice President and Head of Energy Solution Business Division at SK Innovation. “SK Innovation will work closely with KHNP to support the Wyoming project, pursue new nuclear opportunities, and achieve innovative outcomes including localisation of key materials and components.”
