Kairos Power breaks ground on first power-producing reactor in Oak Ridge

On April 17, Kairos Power broke ground on its Hermes 2 demonstration plant in Oak Ridge, Tenn, for which it received test reactor construction permits from the Nuclear Regulatory Commission in November 2024. Kairos expects Hermes 2 to begin operations by 2030, when the fluoride salt-cooled high temperature reactor could become the first NRC-licensed non-light water reactor to produce power.

The ground breaking also served as a broader celebration of the progress Kairos has made at its Oak Ridge reactor demonstration campus, where elected officials, community members, and commercial partners toured active construction and listened to remarks from company and government leaders, who described the legacy of the site and the urgency for new nuclear deployments.

Erik Olds, site manager for the Department of Energy's Oak Ridge Office of Environmental Management, framed the day in the context of the site's eight-decade history. Olds described how nearly 85 years ago, some 30,000 construction workers transformed the same area from orchards and farmland into a uranium enrichment complex that played a central role in the Manhattan Project, housing operations that would operate for the next four decades. After the Cold War, the site underwent a lengthy environmental cleanup effort that spanned years, work that Olds said has made new construction possible. "[Kairos] helped us achieve our vision for the site," he said, "that we can do something with these cleaned-up lands once we're finished with our work."

The historical parallels were not lost on attendees-nor was the pressure to deliver. Deputy Secretary of Energy James Danly pointed to surging electricity demand driven by AI and the reshoring of manufacturing as the driving forces behind the renewed push for nuclear power. "Gone are the days where you could wait 10 years to build a factory," Danly said. "We need power immediately."

Kairos is using an iterative development model to meet that urgency. "For nuclear projects to be successful, we need more than just the right technology," said Mike Laufer, Kairos Power cofounder and CEO. "We need to understand every aspect of project delivery. Hermes 2 is where that all comes together."

Hermes 2 was originally approved by the NRC as a nonpower test reactor facility in late 2024, with a licensed lifetime of 11 years. The permits authorized Kairos to build a facility with two molten salt-cooled 35-MWt test reactors and demonstrate power production of 20 MWe. Plans changed with a power purchase agreement between the Tennessee Valley Authority and Google, leading Kairos to announce a change to a 50-MWe output for the Hermes 2 site.

Kairos Power started constructing Hermes 2's predecessor, Hermes, at the same Oak Ridge site in 2024. Hermes is designed solely as a nonpower demonstration unit and follows three iterations of an Engineering Test Unit series to test the reactor vessel design.

Hermes 2 will be built using a factory-based manufacturing model that Kairos says has the potential to transform nuclear project delivery. Reactor equipment modules will be fabricated at the company's Manufacturing Development Campus in Albuquerque, N.M., and shipped to Oak Ridge for assembly. The civil structure will incorporate precast concrete and a seismically isolated foundation-construction methods the company says are expected to shrink project timelines, lower costs, and enable a standardized, repeatable design scalable across a future commercial fleet.

Laufer said the proof of that method is written into the ground beneath Hermes 2 itself. The team encountered unexpected legacy infrastructure during excavation for the construction of Hermes, which gave them insights on what lay beneath the adjacent Hermes 2 site, turning what could have been a costly surprise into a documented, manageable process.

"For Hermes 2, we know exactly what we need to do to manage that legacy infrastructure and how to remove it in a cost-effective and schedule-efficient way," Laufer said, "and that would not have been possible if we had just gone out and done it cold. This is a real, tangible time and money savings from the iterative process."

As the immediate precursor to Kairos's full-scale commercial plants, Hermes 2 is expected to advance technology, licensing, supply chain, and construction certainty for future deployments.

"It's not lost on us that the urgency of this moment has only increased," Laufer said. "The country needs everything that nuclear power can deliver, and the burden is on us to prove that we can deliver it. We take that responsibility seriously."