Google Backs Advanced Nuclear at TVA’s Clinch River as ORNL Pushes Quantum Frontiers

At the end of August, Google announced its first advanced nuclear reactor project in partnership with Kairos Power and the Tennessee Valley Authority (TVA). Under the agreement, Google will become the first corporate customer for an advanced reactor in the United States. The collaboration centers on the Hermes 2 project, a 50-megawatt reactor scheduled to begin delivering carbon-free electricity by 2030. TVA will integrate that power into its regional grid and supply it to Google data centers in Tennessee and Alabama.

The partnership builds on a Master Plan Development Agreement signed in October 2024 between Google and Kairos Power, aimed at developing up to 500 MW of next-generation nuclear capacity by 2035. The long-term strategy calls for multiple plants sited near Google data centers, with the two companies working together on technology development and commercialization. As Kairos Power CEO and co-founder Mike Laufer explained at the time:

Clinch River: TVA’s Testbed for Advanced Nuclear

The Clinch River project marks the first significant step toward commercial power delivery under the Google–Kairos agreement. Kairos Power is developing its Hermes molten salt–cooled reactor at TVA’s Clinch River site in Oak Ridge, Tennessee — a location long earmarked for nuclear innovation and regulatory readiness. The site is also where TVA has pursued licensing for other small modular reactor (SMR) designs, including GE Vernova’s BWRX-300.

Once operational, TVA will purchase electricity from the Kairos plant and supply it to Google, strengthening the company’s ability to match its regional data center load with clean power. TVA already operates seven nuclear reactors across three generating stations in Tennessee and Alabama, making nuclear a cornerstone of its energy mix.

While the Hermes reactor’s innovations lie in scale and design rather than in producing “cleaner” electrons, the partnership underscores TVA’s commitment to advanced nuclear. TVA President and CEO Don Moul emphasized the significance of the collaboration:

Inside the Hermes Reactor Design

Kairos Power’s Hermes reactor is based on its KP-FHR architecture — short for fluoride salt–cooled, high-temperature reactor. Unlike conventional water-cooled reactors, Hermes uses a molten salt mixture called FLiBe (lithium fluoride and beryllium fluoride) as a coolant. Because FLiBe operates at atmospheric pressure, the design eliminates the risk of high-pressure ruptures and allows for inherently safer operation.

Fuel for Hermes comes in the form of TRISO particles rather than traditional enriched uranium fuel rods. Each TRISO particle is encapsulated within ceramic layers that function like miniature containment vessels. These particles can withstand temperatures above 1,600 °C — far beyond the reactor’s normal operating range of about 700 °C. In combination with the salt coolant, Hermes achieves outlet temperatures between 650–750 °C, enabling efficient power generation and potential industrial applications such as hydrogen production.

Because the salt coolant is chemically stable and requires no pressurization, the reactor can shut down and dissipate heat passively, without external power or operator intervention. This passive safety profile differentiates Hermes from traditional light-water reactors and reflects the Generation IV industry focus on safer, modular designs.

From Hermes-1 to Hermes-2: Iterative Nuclear Development

The first step in Kairos’ roadmap is Hermes-1, a 35 MW thermal demonstration reactor now under construction at TVA’s Clinch River site under a 2023 NRC license. Hermes-1 is not designed to generate electricity but will validate reactor physics, fuel handling, licensing strategies, and construction techniques.

Building on that experience, Hermes-2 will be a 50 MW electric reactor connected to TVA’s grid, with operations targeted for 2030. Under the agreement, TVA will purchase electricity from Hermes-2 and supply it to Google’s data centers in Tennessee and Alabama.

Kairos describes its development philosophy as “iterative,” scaling incrementally rather than attempting to deploy large fleets of units at once. By phasing growth, the company aims to avoid the delays and cost overruns that have dogged traditional nuclear projects.

If successful, Hermes-1 will establish operational experience, Hermes-2 will demonstrate commercial readiness, and later projects will scale toward the 500 MW of advanced nuclear capacity outlined in Kairos’ 2024 Master Plan agreement with Google. For Google, the initiative provides a new clean energy pathway to meet the surging power needs of its AI data centers — without shifting development and financing burdens onto TVA’s ratepayers, a growing concern as utilities confront the demands of AI “factory” buildouts.

Also for Google, Hermes represents more than a power purchase — it’s a template for how hyperscalers can secure scalable, carbon-free energy for AI data centers, while advancing technologies that could also underpin the next era of high-performance and quantum computing.

The story of advanced computing in Tennessee didn’t end with nuclear. Just days after Google and Kairos made headlines, Oak Ridge National Laboratory unveiled a breakthrough that points toward the next chapter of high-performance computing.

ORNL Debuts Diamond-Based Quantum Cluster

On September 2, 2025, Oak Ridge National Laboratory (ORNL), working with Australia’s Quantum Brilliance, announced the deployment of the nation’s first on-site, commercial, diamond-based quantum–classical hybrid computing cluster. The system, housed at the Oak Ridge Leadership Computing Facility (OLCF), integrates directly into the lab’s existing HPC ecosystem.

The installation includes three Quantum Development Kits (QDKs), each built around a diamond-based Quantum Processing Unit (QPU). Together, they deliver six qubits that operate entirely at room temperature in a rugged, compact package, eliminating the cryogenics and complex cooling systems typically associated with quantum machines. Diamond’s intrinsic hardness suppresses thermal vibrations and electromagnetic noise, helping minimize decoherence without the need for vacuum chambers or laser infrastructure.

Testing Hybrid Quantum–Classical Workflows

The six-qubit system has been integrated into ORNL’s Advanced Computing Ecosystem (ACE) testbed, a sandbox environment for exploring emerging computing architectures. Within ACE, the diamond-based processors can be paired with ORNL’s Frontier supercomputer — currently ranked No. 2 on the Top500 list of the world’s fastest systems — to test hybrid quantum–classical workflows. Researchers can access the system through standard network interfaces such as HTTP, enabling practical experimentation with co-processing models at scale.

According to OLCF Program Director Ashley Barker:

According to leaders from both ORNL and Quantum Brilliance, the installation will serve as a proving ground for hybrid and parallel quantum computing architectures. Early work will focus on practical domains such as computational chemistry and machine learning, where quantum acceleration could offer measurable advantages. The system will play a central role in shaping ORNL’s strategy for future leadership-class computing platforms.

For the broader computing landscape, quantum accelerators could eventually deliver the same transformative impact that GPUs had on general-purpose computing — moving from niche tools to essential engines of performance.

That vision was very much in focus this week at the HPC Fall Forum 2025, where discussions centered on how supercomputing, quantum, and national laboratory leadership will converge to define the next era of high-performance infrastructure.

Taken together with Google’s investment in advanced nuclear power, these developments underscore a central theme: the technologies powering AI and data centers are now inseparable from the frontiers of energy and computing itself.

At Data Center Frontier, we talk the industry talk and walk the industry walk. In that spirit, DCF Staff members may occasionally use AI tools to assist with content. Elements of this article were created with help from OpenAI's GPT5.

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