Construction begins on commercial sodium reactor in the US

TerraPower, a company focused on nuclear innovation, celebrated the start of construction on its Natrium1 reactor demonstration project. It is the first advanced reactor project in North America to move from the design phase to construction. The company is notable for being founded by Bill Gates, who has a personal interest in building the sodium reactor. 

"This groundbreaking marks the beginning of a new era in nuclear energy. The Natrium reactor is more than a design; it is a power plant that will drive the clean energy transition and support our historic energy communities,"said Chris Levesque, president and CEO of TerraPower.

Construction began in Wyoming, historically the largest coal-producing state in the US, which is naturally suffering from the decline in coal mining. "Our innovative Natrium technology will provide safecarbon-free energy and gigawatt-scale energy storage," Levesque added. 

At the peak of construction, the project will require approximately 1,600 workers, and construction is scheduled to take five years. Once the plant is operational, the company estimates that 250 people will support its day-to-day operations, including plant security. The reactor is being built near a coal-fired power plant that is being retired, and it is the only coal-to-nuclear transition project in the world to have begun construction. 

Construction itself has begun only on the non-nuclear parts, starting the review of the permit application by the Nuclear Regulatory Commission, the local nuclear regulator. Once approved, the permit will allow construction of the nuclear reactor itself to begin.The review process will take a few years, so in the meantime TerraPower will continue building the non-nuclear parts of the facility. Next year, construction will begin on the so-called "energy island", where the steam turbines and other equipment will be located. The reactor will ultimately be part of the "nuclear island", construction of which is expected to begin in 2026.

Through the US Department of Energy's Advanced Reactor Demonstration Program (ARDP) and a public-private partnership, the project is intended to validate the design, construction and operational characteristics of a sodium reactor in practice.

Technical specifications

The Natrium reactor is a sodium-cooled fast reactor with integrated energy storage based on molten salts. This technology allows the reactor to maintain a constant thermal output while increasing its electrical output as needed. This improves its flexibility and ability to integrate with renewable energy sources, an advantage as renewables make up a larger share of the generation mix.

According to the manufacturer, the Natrium reactor is also simpler and cheaper to build than other reactors because it requires fewer safety systems and less material due to its smaller size. It also operates at atmospheric pressure, which entails lower safety risks. Construction of the reactor in Wyoming is planned to take just under 5 years. 

The Natrium reactor is expected to have a thermal output of 840 MWt, an electrical output of 345 MWe directly from the reactor and 100-500 MWe from the energy storage system, which can supply power continuously for 5.5 hours and change its output by 10% per minute. The reactor itself produces heat at a temperature above 500 degrees Celsius, which can be used in other industrial processes.