By 2030, Kairos Power aims to demonstrate electricity production from a full-scale, 140-MWe fluoride salt–cooled high-temperature reactor, the KP-X. In service of that goal, Kairos plans to demonstrate Hermes, a scaled-down 35-MWth nonpower reactor, in Oak Ridge, Tenn.
Hermes is being built to “prove our ability to deliver affordable nuclear heat,” said Mike Laufer, Kairos Power chief executive officer and cofounder, as he explained Kairos’s plans to the local community during a September 28 webinar now available to view on demand. Laufer took questions, and Kairos took the opportunity to introduce a virtual open house that visitors can tour to view videos and interactive features and even submit comments.
The welcome mat: Local elected officials representing Oak Ridge and its environs offered a warm welcome to kick off the webinar. Kathy McCarthy, associate laboratory director for fusion and fission energy and science at Oak Ridge National Laboratory, spoke about a partnership between Kairos and ORNL, which she said is attracting new talent to the lab.
ORNL hosted the Molten Salt Reactor Experiment, which went critical in 1965, and Kairos is leveraging ORNL’s expertise in molten salt. “ORNL considers Kairos an important partner,” McCarthy said, adding that “They can keep to schedule.”
While Kairos Power expects Hermes to be operational in 2026, McCarthy referenced a plan to get Hermes operating by the 60th anniversary, in June 2025, of the MSRE's achieving criticality, a plan that Laufer said is aggressive, “even by our standards.” Laufer acknowledged, however, that Kairos is working to get Hermes up and running as close as possible to that milestone anniversary.
Design essentials: Kairos Power wants to commercialize its technology at a price competitive with natural gas generation. Unlike molten salt reactors that would use liquid fuel dissolved in the coolant, Kairos would use TRISO fuel fabricated into pebbles about the size of a golf ball. “Kairos is trying to combine these technologies that have not historically been combined,” Laufer said, adding that he believes the safety case and economics of the reactor go hand in hand.
Kairos is attempting to expedite the development of the KP-X through a series of testing iterations and early engagement with the Nuclear Regulatory Commission. “Early on we recognized the need for nonnuclear demonstrations,” Laufer said. Hermes will be preceded by a non-nuclear Engineering Test Unit of the same scale—which Laufer said will be the largest Flibe unit ever built—and will be followed by a larger non-nuclear test unit, dubbed the U-Facility.
Not your typical host community: Questions from webinar attendees made clear the depth of technical knowledge of the many current and former ORNL employees who make their home in Oak Ridge. The subject of the questions included waste disposal plans, Hermes’s low-pressure coolant system, and the extent of below-grade construction permitted at the brownfield site of the former K-33 gaseous diffusion plant in the East Tennessee Technology Park where Hermes will be built.
Kairos first announced its plans to redevelop the former K-33 gaseous diffusion plant site in December 2020, and, according to Laufer, the decision to build Hermes was made only 16 months ago. Kairos Power is investing $100 million in the project, and it was awarded $303 million in Risk Reduction funding from the Department of Energy’s Advanced Reactor Demonstration Program, which is also supporting full-scale demonstrations of TerraPower’s Natrium reactor in Wyoming and X-energy’s Xe-100 in Washington. In May, Kairos Power announced that the Tennessee Valley Authority would collaborate on deploying Hermes by providing engineering, operations, and licensing support.
Expansive plans: For Kairos, Oak Ridge represents one more site supporting the work of an expanding team of about 210 employees working across the country, about 90 percent of whom are engineering staff. The company’s headquarters is located in Alameda, Calif., and the Engineering Test Unit and production development facility are in Albuquerque, N.M. A licensing office is located in Charlotte, N.C., and a molten salt pilot plant, in Elmore, Ohio, is tasked with producing the liquid fluoride salt coolant.