Frequently Asked Questions

Below is a selection of common questions about the Natrium project. If you need additional information please reach out to

Why is the Natrium reactor needed when we could just invest in more renewables and storage?

America's energy grid will increasingly rely more heavily on wind and solar. The Natrium plant is specifically designed to integrate into a grid with high levels of variable-output renewables.

The Natrium technology will use the high-temperature heat from the reactor to power a molten salt storage system that can retain tremendous amounts of energy, much greater than the energy stored in typical battery facilities. That energy can be used to power the grid at peak demand when weather and darkness hamper renewable output.

Which licensing framework will TerraPower pursue with the NRC to license the Natrium reactor?

The Nuclear Regulatory Commission (NRC) licenses and regulates the operation of all commercial nuclear power plants in the United States. TerraPower will pursue the 10 CFR Part 50 licensing pathway for the Natrium reactor. TerraPower, through its subsidiary, US SFR Owner, submitted the demonstration plant's construction permit application in 2024 and anticipates submitting the operating license application in 2027.

When is construction slated to begin?

TerraPower (through its subsidiary, US SFR Owner) submitted the demonstration plant's construction permit application to the U.S. Nuclear Regulatory Commission (NRC) in March 2024 and anticipates submitting the operating license application in 2027. This will allow us to begin construction on the nuclear island in 2026 with completion of the plant this decade. Construction on the non-nuclear portion of the plant began in June 2024.

How will subcontractors be selected, and can local business get involved?

The Natrium plant is being built through a public-private partnership including a large U.S. government grant, and we will follow all federal contracting and tendering rules. We are planning for Bechtel Corporation to build the reactor with the help of many direct employees and subcontractors. There is strong capability in Wyoming, and the project will be looking for local partners. The improved logistics of partnering with nearby vendors will be a success factor for the project. Bechtel is leading most of the vendor selection for construction materials and services - more information can be found at

How much will the Natrium reactor demonstration project cost?

TerraPower is building its first plant through a public-private partnership with the U.S. Department of Energy's (DOE) Advanced Reactor Demonstration Program (ARDP). This program authorizes a 50/50 cost share and authorizes up to $2 billion for the Natrium project. TerraPower and partners will match this investment dollar for dollar. The first-of-a-kind cost for the Natrium demonstration plant will include the reactor design and licensing, codes and methods development, construction of the sodium test facility, development of a fuel fabrication facility and fuel development and qualification.

What type of fuel does the Natrium reactor use?

The Natrium reactor uses high-assay, low-enriched uranium (HALEU) metallic fuel. HALEU is a new class of nuclear fuel where the uranium-235 isotope content is above 5% but less than 20%. Many advanced reactors, including the Natrium technology, use HALEU because it improves reactor performance. HALEU allows the Natrium reactor to more efficiently produce energy and reduces the volume of waste produced from the reactor, when compared to today's operating nuclear fleet.

Is the Natrium plant safe?

Yes. The Natrium technology enhances safety, relying on natural forces and advanced design for passive heat removal. In addition, the Natrium reactor operates at atmospheric pressure and uses sodium, instead of water, as its coolant. The reactor operates at a temperature more than 350 degrees Celsius (the equivalent of 662 degrees Fahrenheit) far below the boiling point of sodium.

Further, the Natrium reactor is a pool-type reactor, so there are no penetrations in the reactor vessel below the lid, which eliminates the possibility of a leak or loss of coolant accident. The design also relies on natural forces, like gravity and hot air rising, to cool the reactor if an unexpected shutdown occurs. This means the plant does not rely on power to cool itself.

How big is a Natrium plant?

The entire size of the nuclear island is approximately 16 acres. The overall site area is approximately 44 acres. When normalized to power rating, the Natrium system has a smaller footprint compared to other Generation IV reactors.


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