The Nuclear Regulatory Commission (NRC) has made history by approving the construction of the first-ever molten-salt reactor to power the grid in the United States. Following the Commission’s vote, Hermes 2 is now the first electricity-producing Gen IV plant to be approved for construction in the United States.
This landmark approval was granted to Kairos Power, which is building the Hermes Low-Power Demonstration Reactor at the Heritage Center Industrial Park in Oak Ridge, Tennessee. This development signals a significant milestone in the pursuit of carbon-free energy solutions, showcasing the potential of Generation IV nuclear power a safer and more efficient version of traditional nuclear technology.
The Comeback of Nuclear Fission Technology
As the world intensifies efforts to combat climate change, nuclear fission technology is making a strong comeback. Unlike earlier designs, Generation IV reactors prioritize safety and fuel efficiency. They are engineered to prevent the release of radioactive material, even in extreme situations like earthquakes.
One of the most promising approaches under this technology umbrella is molten-salt reactors. These reactors use molten salt as a coolant, operating at higher temperatures for greater efficiency. In some designs, the nuclear fuel is dissolved in the molten salt, while in others, it is embedded in graphite. Kairos Power employs the latter method for its Hermes reactors.
Kairos Power’s Innovative Approach to Nuclear Energy
Founded in 2016, Kairos Power is leading the way with a unique reactor design, a graphite-moderated pebble-bed reactor cooled by fluoride salt. The reactor uses TRISO (tri-structural isotropic) particle fuel, which is packed in pebble form. This fuel has an enrichment of nearly 20% high-assay low-enriched uranium (HALEU), making it highly efficient.
What sets Kairos apart is its rapid iterative development approach, which includes:
- Building Engineering Test Units (ETUs) at its Albuquerque and Oak Ridge facilities.
- Using non-nuclear tests to validate critical components like coolant flow and heat transfer rates under controlled conditions.
- Developing in-house manufacturing capabilities to reduce technology and supply chain risks.
These steps help Kairos clear regulatory hurdles efficiently, enabling faster progress toward its goals.
Breaking Ground with Hermes 1 and Hermes 2
In December 2023, Kairos Power achieved a major breakthrough when the NRC approved the construction of Hermes 1, the first Generation IV reactor in the US. Located in Oak Ridge, this low-power reactor will not generate electricity but will serve as a demonstration unit to test system integration and operational safety.
Building on this success, Kairos Power received the green light for Hermes 2, a power plant designed to supply electricity to the grid. Highlights of Hermes 2 include:
- Two 35-MWth reactors with a combined capacity of 20 MWe.
- A scaled-down version of a full plant architecture to test and refine operational processes.
- Carbon-free energy production, contributing to a sustainable energy future.
Christopher Hanson, NRC Chair, highlighted the efficiency of the approval process:
“While keeping safety at the forefront, the permitting process was quite efficient, and we issued these permits in less than 18 months.”
The approval for Hermes 2 came after just 16 months, thanks to Kairos’ extensive pre-application engagement with the NRC, which began in 2018.
The Road Ahead for Kairos and the Nuclear Industry
The success of Kairos Power is more than just a win for the company, it’s a milestone for the nuclear industry. With the NRC looking to simplify its regulatory processes for future projects, the path is being paved for faster adoption of Generation IV technology.
As NRC Chair Christopher Hanson remarked: “This shows we can rapidly apply relevant conclusions from earlier reviews to promptly reach decisions on new reactors.”
By demonstrating that innovation and safety can go hand in hand, Kairos Power is setting the stage for a new era of carbon-free nuclear energy.
Why This Matters
The approval of Hermes reactors represents a turning point in how the US meets its energy demands. As the world searches for reliable, sustainable, and efficient energy sources, technologies like those developed by Kairos Power could play a key role.
From improving fuel efficiency to ensuring greater safety, Generation IV nuclear reactors are designed to overcome the challenges of traditional nuclear energy. The Hermes project not only marks progress in nuclear innovation but also demonstrates the effectiveness of collaboration between the private sector and regulatory bodies.
A New Dawn for Nuclear Energy
Kairos Power’s success shows how advanced technologies can align with modern energy needs, offering hope for a carbon-free future. With the NRC’s streamlined approval processes and companies like Kairos leading the charge, the nuclear industry is entering a transformative phase.
As we look to the future, the potential of Generation IV nuclear power to meet energy demands safely and sustainably cannot be overstated. For policymakers, innovators, and environmental advocates, this is a moment to celebrate and to build upon.
