Joint efforts of Argonne and private industry further nuclear reactor developments
Partnerships between the nuclear industry and national laboratories are making overall codes more robust and capable. (Photo: Argonne)
The development of modern nuclear reactor technologies relies heavily on complex software codes and computer simulations to support the design, construction, and testing of physical hardware systems. These tools allow for rigorous testing of theory and thorough verification of design under various use or transient power scenarios.
Kairos Power’s Hermes 2 demonstration plant (blue-topped building on the left) is planned to be built next to the Hermes demonstration reactor. (Image: Kairos Power)
A notice of opportunity from the Nuclear Regulatory Commission was published in the November 22 Federal Register to intervene in an adjudicatory hearing on Kairos Power’s application for a construction permit to build the Hermes 2 test reactor facility in Oak Ridge, Tenn.
The Engineering Test Unit at KP Southwest. (Photo: Kairos Power)
In October, staff at Kairos Power’s testing and manufacturing facility in Albuquerque, N. M., began transferring 14 tons of molten fluoride salt coolant into an Engineering Test Unit (ETU)—the largest transfer of FLiBe (a mixture of lithium fluoride and beryllium fluoride) since the Molten Salt Reactor Experiment in 1969.
Conceptual art of the Hermes low-power demonstration reactor. (Image: Kairos Power)
The Nuclear Regulatory Commission staff has completed its final environmental impact statement (FEIS) for Kairos Power’s application to build the Hermes demonstration reactor in Oak Ridge, Tenn., and is advising that the construction permit (CP) be issued.
“After weighing the environmental, economic, technical, and other benefits against environmental and other costs, and considering reasonable alternatives, the NRC staff recommends, unless safety issues mandate otherwise, that the NRC issue the CP to Kairos,” the FEIS states.
A rendering of the Hermes low-power demonstration reactor. (Image: Kairos Power)
Having completed its review of the construction permit application for Kairos Power’s Hermes test reactor early last month, the Nuclear Regulatory Commission’s Advisory Committee on Reactor Safeguards (ACRS) recently submitted its conclusions to the agency, recommending approval.
An artist’s rendering of Hermes. (Image: Kairos Power)
The Nuclear Regulatory Commission issued a draft environmental impact statement (EIS) recently on Kairos Power’s application for a permit to construct Hermes, a 35-MW nonpower version of the company’s fluoride salt–cooled reactor design (KP-FHR), at the East Tennessee Technology Park in Oak Ridge, Tenn.
How Kairos Power is applying rapid iterative development to the licensing process as part of its strategy to deliver on cost

Laufer
Developing a first-of-a-kind reactor is a daunting endeavor. To be successful, advanced reactor designers need to achieve cost certainty by delivering a safe and affordable product at the promised cost. To meet this goal, Kairos Power structured its approach around four key strategies: 1) achieving technology certainty through a rapid iterative approach; 2) achieving construction certainty by demonstrating the ability to build it; 3) achieving licensing certainty by proving Kairos can license it; and 4) achieving supply chain certainty by vertically integrating critical capabilities. By mitigating risk in these four key areas, Kairos Power is confident that it will get true cost certainty for our future products.
The third prong in Kairos’s strategy—achieving licensing certainty—was a key driver in the decision to build the Hermes low-power demonstration reactor, and it remains a major workstream as the company’s construction permit application (CPA) undergoes review by the U.S. Nuclear Regulatory Commission. Licensing a new nuclear technology is no small challenge, and there are multiple approaches companies can take. Here’s a look at how we at Kairos are approaching it.
Artistic rendering of the Hermes low-power demonstration reactor, a scaled-down demo of the KP-FHR. (Image: Kairos Power)
The Nuclear Regulatory Commission recently issued a draft safety evaluation report indicating initial acceptance of Kairos Power’s source term methodology for its fluoride salt–cooled high-temperature reactor (KP-FHR).