Kairos breaks ground for Hermes 2 reactor

Hermes 2 is Kairos Power's first deployment under its 2024 agreement with Google to develop an advanced reactor fleet. It will supply up to 50 MW of electricity to the Tennessee Valley Authority grid, helping to decarbonise Google data centres in Tennessee and Alabama.

The company is already building the Hermes Low-Power Demonstration Reactor - Hermes 1 - in Oak Ridge, a scaled demonstration of Kairos's KP-FHR fluoride salt-cooled high-temperature reactor technology. The first non-light-water reactor to be approved for construction by the US Nuclear Regulatory Commission, Hermes 1 will not produce electricity, but Kairos's iterative approach to development will see lessons learned from the project feeding into Hermes 2.

The Hermes series will be the first KP-FHRs ever built, the company said, incorporating proven nuclear technologies that originated in Oak Ridge including TRISO (tri-structural isotropic) coated particle fuel and Flibe molten fluoride salt coolant. Hermes 2 - which is being built on the footprint of the former Oak Ridge Gaseous Diffusion Plant - is the immediate precursor to full-scale commercial plants, and will further advance technology, licensing, supply chain, and construction certainty for the company's future deployments, it said.

_{The Hermes demonstration campus in Tennessee (Image: Kairos Power)}

Kairos Power will fabricate equipment modules for the Hermes 2 reactor at its Manufacturing Development Campus in Albuquerque, New Meixico, and ship them to Oak Ridge for assembly. The Barnard Construction Company, Inc is the general contractor for both Hermes reactor projects.

The Hermes 2 civil structure will leverage modular construction methods, incorporating precast concrete and a seismically isolated foundation, and the construction methods piloted with the Hermes series are expected to shrink project timelines, lower nuclear construction costs, and enable a standardised, repeatable design, the company said.

"For nuclear projects to be successful, we need more than just the right technology. We need to understand every aspect of project delivery. Hermes 2 is where that all comes together," said Kairos Power CEO and co-founder Mike Laufer.

Amanda Peterson Corio, Global Head of Data Center Energy, Google, said the Hermes 2 grounbreaking was a "major leap forward" in the company's efforts to accelerate the commercialisation of affordable, carbon-free energy,. "By pioneering a standardised, repeatable design, Kairos Power is addressing the historical challenges of nuclear construction costs. This shift toward a more efficient, factory-based manufacturing approach is a proven path toward lower-cost, cleaner power for our operations and the communities we serve."