‘Building on the shoulders of Titans’ | Kairos Power breakes ground on Hermes 2 construction
The company's first power-producing reactor will supply up to 50 megawatts to the TVA grid by 2030, fulfilling the first delivery under its landmark deal with Google.
Kairos Power officially broke ground Friday on its Hermes 2 reactor in Oak Ridge, becoming the first company to receive a Nuclear Regulatory Commission (NRC) construction permit for a power-producing Generation IV reactor in United States history.
The milestone puts the California-based advanced nuclear company squarely at the center of a new chapter in East Tennessee’s long nuclear legacy. It also delivers on the clock to bring electrons to the grid by 2030.
“We’re here today to celebrate the groundbreaking event for our Hermes 2 reactor, but we’re also here to celebrate a lot of the hard work that’s led to this moment,” said Edward “Ed” Blandford, co-founder and chief technology officer of Kairos Power.
That hard work spans more than a decade of iterative development and, more broadly, more than 70 years of nuclear history on the same soil. Hermes 2 will be built on the same grounds as the former K-33 site at the East Tennessee Technology Park, one of two facilities originally constructed in the 1950s as part of the nation’s effort to increase enriched uranium production. Kairos acquired the K-33 and adjacent K-31 sites in 2021 after the U.S. Department of Energy completed a historic cleanup and returned the land to the community for economic development.
“Every time I come on this site, I still have chills,” Blandford said. “The history, the legacy of the site, the proximity to the K-25 site — we really feel like we’re building on the shoulders of titans in terms of the community here.”
About 150 community, government, and business leaders gathered for a half-day ceremony on Friday, which included site tours and remarks from elected officials and commercial partners. U.S. Deputy Secretary of Energy James P. Danly attended, along with representatives from Tennessee Valley Authority (TVA) and Google. U.S. Rep. Chuck Fleischmann, chairman of the House Energy and Water Appropriations Subcommittee, and Tennessee Governor Bill Lee also provided virtual remarks.
An iterative path to power
Kairos has been building its presence in Oak Ridge for several years. The company successfully built and tested its non-nuclear Engineer Test Unit (ETU) Version 3 at the site, which served as a training and remote-handling platform for future reactor operations. Construction on its Hermes 1 low-power demonstration reactor began roughly two years ago and was still actively underway during Friday’s ceremony. Kairos Power contracted with Barnard Construction Company, a heavy-civil construction company, to perform site work and excavation at the site in Oak Ridge.
Hermes 2 is designed to build directly on the lessons learned.
“We learned a lot from ETU 3 and how to apply it to Hermes 1, and we’re excited to apply what we learned to Hermes 2,” Blandford said.
Where Hermes 1 is a low-power demonstration unit, Hermes 2 is Kairos’s first commercial-scale plant, designed to supply up to 50 megawatts of electricity to the TVA grid. That power will help decarbonize Google data centers in Tennessee and Alabama — the first delivery under the pair’s master plant development agreement announced in 2023.
Smaller scale leads to a faster timeline
The reactor uses fluoride-salt-cooled high-temperature technology, incorporating TRISO-coated particle fuel and Flibe molten fluoride salt coolant. As Joe Hoagland, the associate laboratory director for Oak Ridge National Laboratory (ORNL) Fusion and Fission Energy and Science Directorate, said at the ceremony, all of these materials have roots in ORNL research.
Current operating nuclear plants typically function at the gigawatt scale, serving millions of homes. However, Hermes 2 will operate at the megawatt scale, which Blandford says is a deliberate strategic advantage.
“One of the advantages of the types of technologies Kairos is developing is that they’re smaller scale, so they require less capital to build,” he said. “That creates opportunities to potentially bring the construction schedule down and bring electrons to the market sooner.”
Kairos will fabricate reactor equipment modules at its manufacturing campus in Albuquerque, New Mexico, then ship them to Oak Ridge for assembly.
Blandford explained that the factory-built approach is new in the nuclear space and has the potential to transform expectations for nuclear delivery timelines. The Hermes 2 civil structure will also use modular construction methods, including precast concrete and a seismically isolated foundation.
The importance of the partnership agreement
The Google and TVA relationships give Kairos something rare in advanced nuclear: a known buyer before the plant is built.
“Hermes 2 is the first power plant we’re putting under our master plant development agreement with Google, and we have a partnership with TVA for the offtake of electrons,” Blandford said. That pre-arranged offtake reduces market risk and strengthens the commercial case for the technology as Kairos eyes future full-scale deployments.
TVA Senior Vice President and Chief Nuclear Officer Matt Rasmussen called the project a demonstration of “how advanced nuclear will strengthen our nation’s energy dominance by delivering affordable, reliable power at scale.”
For Blandford, the Oak Ridge location is integral.
“Oak Ridge has been very welcoming to us from the very beginning when we were looking for sites,” he said. “It’s been a terrific community for us to work with.”
Learn more about Kairos Power.
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