50-MW facility will provide power for Google data centres in Tennessee and Alabama
US advanced nuclear reactor developer Kairos Power has broken ground on its Hermes 2 Demonstration Plant in Oak Ridge, Tennessee – the company’s first commercial-scale reactor and the first power-producing Generation IV reactor to receive a construction permit from the US Nuclear Regulatory Commission (NRC).
Hermes 2 is Kairos Power’s first deployment under its landmark deal with Google to develop an advanced reactor fleet. The company said the plant will supply up to 50 MW of clean electricity to the grid of federally owned utility Tennessee Valley Authority (TVA), helping to decarbonise Google data centres in Tennessee and Alabama.
Hermes 2 will build on lessons learned from the Hermes Low-Power Demonstration Reactor (Hermes 1), for which nuclear construction began at the same site last year.
Kairos said the Hermes series will be the first fluoride salt-cooled high-temperature reactors (KP-FHRs) ever built, incorporating proven nuclear technologies that originated in Oak Ridge, which simplify the reactor’s design, lower capital costs and yield “robust inherent safety”. The technology uses Triso coated particle fuel and Flibe molten fluoride salt coolant.
As the immediate precursor to Kairos Power’s full-scale commercial plants, Hermes 2 will further advance technology, licensing, supply chain, and construction certainty for the company’s future deployments.
Fluoride salt-cooled high-temperature reactors fluoride salt-cooled high-temperature reactors are advanced nuclear reactors that operate at low pressure and high temperatures, enabling efficient electricity generation and high-temperature process heat for industrial applications while providing robust passive safety.
The molten salt coolant remains liquid at very high temperatures and does not require high-pressure vessels, reducing accident risks. The salt acts as an excellent heat transfer medium, allowing for compact reactor designs.
At a groundbreaking event Kairos Power chief executive officer and co-founder Mike Laufer 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.
“Oak Ridge, Tennessee, is our hub for nuclear construction and operations. We're training a real workforce to do nuclear construction, learning from the Hermes 1 experience, and translating that knowledge to the Hermes 2 project next door.”
