The United States took a major step toward the next generation of nuclear energy after the U.S. Nuclear Regulatory Commission approved a construction permit for TerraPower’s first Natrium reactor.
The permit allows the company to begin building Kemmerer Unit 1, a commercial-scale advanced nuclear power plant in Wyoming. Notably, this is the first advanced reactor project in the U.S. to receive such approval, marking an important milestone for the future of clean energy and nuclear innovation.
Developed by TerraPower in partnership with GE Vernova Hitachi Nuclear Energy, the Natrium system combines a 345-megawatt sodium-cooled fast reactor with a molten salt energy storage system. The project is also supported through the U.S. Department of Energy Advanced Reactor Demonstration Program.
With regulatory approval secured, TerraPower plans to begin construction within weeks and aims to complete the plant by 2030.
A Long Regulatory Journey Reaches a Breakthrough
Securing approval for a new nuclear design is a rigorous and lengthy process. TerraPower spent more than four years working closely with regulators to reach this stage.
The company first engaged with the NRC through extensive pre-application consultations. These discussions helped refine the reactor’s design and ensured regulators fully understood the new technology. TerraPower then submitted its official construction permit application in March 2024, and the NRC formally accepted the filing in May 2024.
Initially, the regulator expected the review process to take 27 months. However, the timeline moved faster than anticipated.
Several factors helped accelerate the review:
- TerraPower submitted a comprehensive technical application.
- The company responded quickly to regulator questions.
- NRC staff prioritized the project’s review.
- Federal policies encouraged faster licensing of advanced reactors.
As a result, the approval process finished in 18 months, making it one of the fastest regulatory reviews for a new nuclear technology in the United States.
This milestone positions TerraPower as a first mover in the advanced reactor market, which many experts see as essential for meeting future energy demand while reducing emissions.
Natrium: A New Kind of Nuclear Reactor
Unlike traditional nuclear plants, the Natrium system uses sodium instead of water as its coolant. This design change brings several operational advantages.
Most existing nuclear facilities rely on light water reactors, which operate under high pressure. In contrast, the Natrium reactor runs at low pressure and high temperatures, reaching more than 350°C (662°F) while remaining far below sodium’s boiling point.
Because of this design, the reactor can rely on natural forces such as gravity and thermal convection for cooling. This passive safety approach reduces the need for complex emergency systems and lowers construction costs.
Another key innovation is the plant’s integrated energy storage system.
The reactor continuously produces 345 megawatts of electricity, ensuring stable baseload power. Meanwhile, molten salt storage can hold excess heat and release it later to boost output to 500 megawatts during periods of high demand.
Instead of running at a constant power level like traditional nuclear plants, the system can adjust electricity production based on grid needs. That flexibility allows it to complement renewable energy sources such as wind and solar.
Thus, this capability makes the Natrium plant unique among advanced reactor designs.
In addition, the design separates the nuclear reactor from the energy storage and power generation systems. This “decoupling” means non-nuclear teams can operate components such as steam turbines and salt tanks outside the nuclear island, improving safety while reducing operational costs.
Supporting Decarbonization Beyond Electricity
The Natrium plant is designed to deliver more than just electricity.
Because the reactor produces high-temperature heat, it can also supply industrial steam and thermal energy. This opens opportunities to decarbonize sectors that are traditionally difficult to electrify, including heavy industry and manufacturing.
The technology can therefore support multiple applications:
- Carbon-free electricity generation
- Industrial heat supply
- Steam production for industrial processes
- Grid stability alongside renewables
With an expected operational life of up to 80 years, the Natrium system could provide reliable low-carbon energy for decades.
Nuclear Power’s Role in America’s Energy Strategy
The approval of TerraPower’s Natrium project comes as the United States seeks to significantly expand its nuclear power capacity.
The U.S. already leads the world in nuclear generation, producing roughly 30% of global nuclear electricity. According to the Energy Department, the country has about 100 gigawatts of nuclear capacity today.
However, the government aims to quadruple that capacity to 400 gigawatts by 2050 to meet growing electricity demand and climate targets.
Federal policies are increasingly focused on rebuilding the nuclear supply chain and accelerating the deployment of new reactors.
Recent initiatives include:
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$2.7 billion investment in uranium enrichment was announced in January 2026 to strengthen the domestic nuclear fuel supply.
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$800 million in funding for small modular reactors was awarded in December 2025 to support projects led by utilities and developers.
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A $1 billion loan to restart the Crane Clean Energy Center nuclear plant in Pennsylvania.
These measures reflect a broader push to ensure the United States maintains leadership in advanced nuclear technology.
Several companies are already developing next-generation reactors, including Oklo, Kairos Power, and X-energy. However, many of those projects are expected to deploy in the mid-2030s.
That timeline makes TerraPower’s Natrium project one of the earliest large-scale demonstrations of advanced reactor technology in the United States.
Rising Power Demand From AI and Data Centers
Another factor driving interest in nuclear energy is the rapid growth of data centers and artificial intelligence infrastructure.
Large technology companies, or the hyperscalers, are building massive data centers to support AI systems and cloud computing. These facilities consume enormous amounts of electricity and require reliable, constant power. As demand grows, many tech companies are exploring nuclear energy to secure their own supply rather than relying solely on public grids.
This trend could reshape the energy landscape. Governments must balance the needs of fast-growing digital industries with the need to keep electricity affordable for households and businesses.
The outcome may also influence the global AI competition between the United States and China, where access to reliable power could become a strategic advantage.
Nuclear Generation Remains Strong in the U.S.
Despite maintenance cycles, nuclear power continued to provide stable and high levels of electricity in 2025. According to the Energy Information Administration (EIA), U.S. nuclear generation stayed consistently strong throughout the year. Output typically dipped during scheduled maintenance periods but rebounded quickly afterward.
The year ended on a particularly strong note. December 2025 recorded about 72–73 million megawatt-hours of nuclear generation, one of the highest monthly totals of the year.
This reliability is one reason policymakers continue to support nuclear energy as a key component of the country’s low-carbon power system.
In conclusion, the construction permit for the Natrium plant signals that advanced reactors are moving from concept to reality. And for TerraPower, the next step is clear: begin construction and prove that advanced nuclear technology can deliver reliable, carbon-free power at commercial scale.