Tennessee

Growing from a broad research effort at U.S. universities and national laboratories, Kairos Power was founded to accelerate the development of a clean, safe, and affordable advanced reactor technology that has the potential to transform the energy landscape in the United States and around the world.

In order to achieve the scale of cost reductions necessary to make advanced reactors competitive with fossil fuels, Kairos Power is singularly focused on the development of a safe and affordable source of energy that will be able to scale to meet the increasing need for dispatchable clean energy. Kairos is currently doing the engineering, manufacturing, and testing necessary to prove that our advanced reactor technology works and can be delivered at the target costs.

Kairos Power plans to build and operate the Hermes Low-Power Demonstration Reactor in Oak Ridge to demonstrate our ability to deliver clean, safe, and affordable nuclear heat. Hermes will be designed to achieve a thermal power level of 35 MWth, compared to 188 MWth for Kairos Power’s future commercial reactors. The construction and operation of Hermes is a key step on our path to commercializing Fluoride Salt-Cooled High-Temperature Reactor (KP-FHR) technology.

The Hermes 2 Demonstration Plant will be co-located with Hermes at Kairos Power's Oak Ridge campus, building on lessons learned from the first Hermes reactor to demonstrate KP-FHR technology at a larger scale and supply clean electricity to the grid.

Kairos Power has construction permits from the U.S. Nuclear Regulatory Commission for both Hermes reactors, and must apply for operating licenses before they can start up. Aligned with our mission to improve people's quality of life while protecting the environment, Kairos Power is committed to protecting the health and safety of everyone who works in, visits, or lives near our Oak Ridge facilities.

The Hermes reactor series will be built at Heritage Center in the East Tennessee Technology Park. Previously home to the K-33 gaseous diffusion enrichment plant, the site was remediated in a historic cleanup effort by the U.S. Department of Energy and returned to the Oak Ridge community for economic investment. Kairos Power acquired the land and announced plans to build there in 2021.

The Hermes Low-Power Demonstration Reactor broke ground in July 2024 and started nuclear construction in May 2025. Construction of the Hermes 2 Demonstration Plant will begin soon. Both plants are targeted to begin operations before the end of the decade.

Kairos Power will be the owner and operator of both Hermes reactors.

Kairos Power is responsible for all costs associated with the construction, operation, and future decommissioning of both Hermes reactors. To date, Kairos Power has been nearly exclusively funded through private investment.

In December 2020, Kairos Power was selected by the U.S. Department of Energy to receive an investment of up to $303 million from the Advanced Reactor Demonstration Program to support Hermes' construction and commissioning. Part of this funding will go to support work at Oak Ridge National Laboratory that will enable the Hermes project.

The location of Oak Ridge, Tennessee, was chosen based on the unique combination of regional workforce capabilities, proximity to highly capable local collaborators, such as Oak Ridge National Laboratory, the University of Tennessee, and the Tennessee Valley Authority, and the infrastructure and characterization data available for the selected site. Tennessee has played an important role in nuclear technology development, and Kairos Power looks forward to building on this legacy to enable the next generation of clean, safe, and affordable advanced reactors for the U.S. energy markets and around the world.