Frequently Asked Questions

As energy demand continues to grow and leaders at all levels of government continue to set ambitious emissions-reduction goals, it is abundantly clear that the world needs more reliable, carbon-free energy. Advanced reactors, like the Natrium™ technology, are uniquely positioned to meet this need.

Demonstrating the Natrium reactor is a crucial part of commercializing this technology and realizing its full potential to meet growing energy demand while combatting climate change.

America’s energy system is going through tremendous change. The grid in Wyoming, and throughout the country, will rely more heavily on wind and solar. A 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, levels of magnitude larger than the energy stored in typical battery facilities. That energy can be used to power the grid at peak demand when the wind isn’t blowing, or the sun isn’t shining. The Natrium technology is a key enabler of wind and solar technologies and integral to the clean energy future.

TerraPower submitted the demonstration plant’s construction permit application to the U.S. Nuclear Regulatory Commission (NRC) in 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 can begin sooner. TerraPower’s Regulatory Engagement Plan, submitted to the NRC, provides more in-depth discussion about the schedule.

The Natrium™ reactor will be one of the first commercially available advanced nuclear technologies. With utilities and policymakers setting ambitious clean energy targets, the Natrium technology is well-positioned to help push the future energy mix toward a cleaner tomorrow.

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. Bechtel Corporation will 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 a majority of the vendor selection for construction materials and services – more information can be found at www.bechtel.com/supplier/

Due to safety concerns at a site under active development, we are not providing tours at this time.

The U.S. Department of Energy ARDP funding includes multiple investments in the domestic supply chain. However, TerraPower does not intend to own a factory. We will be investing in and supporting new investment in U.S. manufacturing capacity. We also anticipate utilizing a number of Wyoming suppliers and vendors.

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, and fuel development and qualification.

Through appropriations including the Infrastructure Investment and Jobs Act signed in November 2021, most of the funds for the DOE ARDP demonstration program have been appropriated. This greatly supports the public-private partnership between DOE and TerraPower to build the reactor, license the technology, and construct a fuel fabrication facility.

The demonstration project will validate our construction approach, establish our supply chain, build our fuel fabrication facility, and help encourage domestic HALEU enrichment capabilities. This will significantly reduce future costs for additional projects.

We anticipate that subsequent plants will have an overnight construction cost between $2,800/KW – $3,000/KW and a levelized cost of electricity – including GW scale energy storage – in the $50-60/MWH range. No other offering provides carbon-free, dispatchable and flexible electricity at this scale anywhere near this cost. TerraPower expects its commercial Natrium plant to cost about $1 billion.

We will be selling this plant to Rocky Mountain Power. The nature of the DOE ARDP agreement makes the risk very different than what’s been done in the past. TerraPower is managing the contract with DOE and taking responsibility for technology development and deployment. This includes potential for cost overruns – typically risks that are assumed by the utility.

TerraPower was originally founded and backed by Bill Gates and other private investors. Currently, Bill Gates is the founder and chairman of TerraPower.

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.

Like any nuclear reactor, the Natrium plant will produce spent fuel, which will be stored safely and securely onsite until a permanent federal geologic repository is identified. Utilities have successfully stored spent fuel onsite at hundreds of locations across the U.S. Additionally, the Natrium technology will reduce the volume of spent fuel compared to conventional reactors because of the efficiency with which it uses fuel.

Yes. Dry cask systems are designed to contain radiation, manage heat and prevent nuclear fission. They must resist earthquakes, projectiles, tornadoes, floods, temperature extremes and other scenarios. The heat generated by a loaded spent fuel cask is typically less than is given off by a home-heating system. The heat and radioactivity decrease over time without the need for fans or pumps. The casks are under constant monitoring and surveillance. Spent fuel is currently in dry storage in 34 states at more than 60 sites. This system has been successfully used at over a hundred sites throughout the United States, with no issues relating to safety or environmental contamination.

While TerraPower is not a uranium company, we recognize our need for a robust domestic HALEU supply chain. That supply chain includes uranium mining, enrichment of uranium into the high-assay low enriched uranium (HALEU), the deconversion of that HALEU into a metal, and the fabrication of the HALEU into fuel rods to power the Natrium reactor.  While there are multiple uranium mines in America, the United States does not currently have commercial scale HALEU enrichment capability, deconversion facilities, or fuel fabrication facilities for Natrium. To date, TerraPower has made multiple investments to advance domestic supply chain capabilities, including:

• In 2021, TerraPower made a multi-million dollar contribution towards an enrichment R&D facility in Piketon, Ohio to help expedite the commercialization of domestic enrichment technology.
• As part of the Advanced Reactor Demonstration Program proposal that was approved by DOE in 2021, we will be investing, along with the federal government, more than $200 million in a domestic fuel fabrication facility to produce the fuel rods that will power our reactor.
• We will also be buying hundreds of millions of dollars worth of HALEU, and are working to use that contract to spur investment into domestic enrichment and deconversion capabilities.

All of those financial commitments were made before Russia invaded Ukraine, but the invasion has reiterated the need to expedite the development of domestic HALEU enrichment capabilities. Congress has appropriated $145 million for a federal fuel availability program, and the Inflation Reduction Act includes $700M related to supporting the availability of HALEU nuclear fuel for research, development and demonstration. This auspicious step will greatly advance the U.S. capacity to make HALEU available for the two ARDP demonstration projects and commercial plants to follow.

TerraPower has partnered with the utility Rocky Mountain Power, a division of PacifiCorp, to advance the Natrium reactor near a retiring coal plant in Kemmerer, Wyoming. The project will allow TerraPower to build the first Natrium plant, which will provide clean, reliable power to the grid and good-paying jobs in Wyoming for decades to come.

Wyoming has a lot to offer and has been a leader in energy for more than 100 years. Wyoming communities understand what it takes to produce energy, and its highly skilled workforce is experienced in building and operating complex projects. The availability of Wyoming’s highly skilled workforce and Rocky Mountain Power’s Naughton coal plant workers is one of the most exciting and valuable aspects of the decision to build near a retiring coal plant in Wyoming. TerraPower is proud to add our technology to Wyoming and Kemmerer’s rich history of energy production. We look forward to partnering with the community and local workforce to provide new clean energy jobs for the region.

Additionally, PacifiCorp is adding a significant amount of renewables and energy storage to the grid to reliably and affordably power Wyoming. The Natrium technology is specifically designed to integrate into a grid with high levels of renewables and is a great match for meeting Wyoming’s grid needs with firm and flexible generation.

TerraPower is partnering closely with community leaders to provide support and counsel to ensure project success and continuity for the community. TerraPower will also engage with the local community and the federal government’s Interagency Working Group on Coal and Power Plant Communities.

The Natrium project would be consistent with the intent of recent Wyoming laws, including SF 159 (2019), HB 74 (2020) and HB 166 (2021). SF 159 was passed in the 2019 Legislature and signed by the governor with a focus on preserving jobs in coal plant communities. HB 74 was enacted in 2020 and enables the replacement of a coal facility with a small nuclear reactor. Further, HB 166 enacted by the 2021 Legislature was intended to ensure that customers will continue to receive reliable electric service if a coal plant is retired. While minor changes in SF 159 may be needed to accommodate a new Natrium facility on a more efficient timeline, the potential for new jobs in coal plant communities is very much aligned with the intent of this legislation, while ensuring on-going reliability of the grid. We are happy to have strong support in Wyoming for the project.

The intent of that law is to allow for smaller reactors to replace the jobs and energy production from coal and gas plants slated to be retired. That’s precisely what PacifiCorp and TerraPower are trying to do here.

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 submitted the demonstration plant’s construction permit application in 2024 and anticipates submitting the operating license application in 2027. Here is a link to the Regulatory Engagement Plan that TerraPower sent to the NRC and made publicly available.

Yes. The Natrium technology enhances safety, relying on natural forces and advanced design. 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) 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.

From its beginnings over a decade ago, TerraPower has made reduction of weapons risks a foundational principle. Natrium reactors are uranium fueled. No Natrium reactor—from the demonstration plant, to the first set of commercial plants, or the subsequent larger plants—will use plutonium as a fuel. The Natrium reactor will run on high-assay low-enriched uranium (HALEU). Natrium plants will not require reprocessing and will run on a once-through fuel cycle that limits the risk of weapons proliferation.

The Natrium plant is expected to be operational this decade.

This will make it one of the first commercially available advanced nuclear technologies. With local leaders and policymakers setting ambitious clean energy targets, the Natrium technology is well-positioned to help push the future energy mix toward a cleaner tomorrow.

The TerraPower team and partners will be working on many different areas like plant design, U.S. Nuclear Regulatory Commission (NRC) licensing, equipment testing and qualification, procurement, construction, operating program development, fuel development and supply, and program management throughout the entire process.

High-level timeline includes:

• 2021 – Project begins and site selected
• 2024 – Nuclear construction permit application to NRC
• 2024 – Early non-nuclear construction begins
• 2025 – Nuclear island construction begins
• 2026 – Operating license application to NRC

Early in the process, the Natrium team selected the site for the demonstration project. The team continues to advance the plant design and will then submit a construction permit application to the NRC in 2024. In parallel, the team will test fuel and equipment, and work with industry to secure the high-assay low-enriched uranium (HALEU) metal fuel and equipment supplies needed for the demonstration project.

Once the construction permit is obtained, the team will proceed with the nuclear construction phase of the project starting in 2025. They will also fabricate the fuel and train operating staff while the NRC reviews the operating license application that will be submitted in 2026. Following issuance of the operating license, the team will proceed with fuel load.

The Natrium demonstration plant will be a fully functioning commercial power plant and, upon completion, the Natrium team will have established the infrastructure needed for a future fleet of plants across the United States and even around the world.

In November 2021, TerraPower announced Kemmerer, Wyoming as the preferred site for the Natrium plant. The Natrium reactor demonstration project’s preferred siting is subject to the finalization of definitive agreements on the site and applicable permitting, licensing and support.

The Natrium project team evaluated a variety of factors when selecting the site of the future Natrium plant. These included local community support, the physical characteristics of the site, the ability to obtain a license from the U.S. Nuclear Regulatory Commission (NRC) for the site, access to existing infrastructure, and the needs of the grid. TerraPower’s technical teams spent five months visiting each community, collecting data, and evaluating this information against our regulatory and project requirements.

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. Similarly, Natrium has a smaller footprint than most multi-unit plants with light water reactors operating today.

At this moment, TerraPower is focused on the demonstration project in Kemmerer, Wyoming. In the future, we plan to sell Natrium plants across the U.S. and around the world. We are confident there is significant demand for the technology.

Since its founding, TerraPower recognized the need for the private sector to take action to develop advanced nuclear energy to meet growing electricity needs and lift billions out of poverty. Given this goal, the company’s Traveling Wave Reactor (TWR) design was originally set to deploy internationally to meet increased demand for clean energy. However, U.S. policy changed in 2018, and the American market opened up new opportunities for deployment with the establishment of the Advanced Reactor Demonstration Program at the U.S. Department of Energy. This prompted the company to explore opportunities to demonstrate its advanced technology in the United States. TerraPower subsequently partnered with GE Hitachi Nuclear Energy to develop the Natrium technology, which combines molten salt energy storage with the best of TerraPower’s TWR and GE Hitachi’s PRISM technologies, along with additional innovations and improvements.

To ensure the technology meets market needs, a team of leading nuclear companies will provide their supply chain, construction, technology and operational expertise. This collaboration aids the transition to a cost-effective, zero-carbon grid, including innovations in siting, licensing, operations and maintenance.

TerraPower, GE Hitachi Nuclear Energy (GEH) and Bechtel submitted a proposal for and were selected as an awardee of the U.S. Department of Energy’s (DOE) Advanced Reactor Demonstration Program (ARDP). The Natrium system is a TerraPower and GE-Hitachi technology. TerraPower and GE Hitachi bring together decades of unparalleled expertise and technical capabilities, and have extensive sodium fast reactor design, analysis, licensing and testing experience spanning decades. For the demonstration project, Bechtel adds current and unmatched experience managing and executing large nuclear projects and the team’s utility partners bring operating capabilities alongside a market demand for utility-scale advanced nuclear technologies.

Rocky Mountain Power, a division of PacificCorp and part of Berkshire Hathaway Energy, who will ultimately operate the plant, is a key partner in the development of the Natrium facility, and the U.S. Department of Energy, who is providing part of the funding for the project, will be involved in the design, licensing, and development of the project.

Finally, TerraPower is receiving advice and technical support from a number of experienced companies and organizations. TerraPower has established a Utility Advisory Group, with members from a variety of utilities from across the country. We will continue to work with national laboratories, including Idaho National Laboratory. TerraPower also has a memorandum of understanding with the Japan Atomic Energy Agency (JAEA), Mitsubishi Heavy Industries and Mitsubishi FBR Systems to share data and resources related to the development of sodium technologies. 

The Natrium technology is a 345 MWe sodium fast reactor coupled with a molten salt-based integrated energy storage system that will provide clean, flexible energy and stability for the grid. The Natrium reactor is a TerraPower and GE-Hitachi technology. The system can boost output to 500 MWe for more than five and a half hours to serve peak demand. The reactor maintains its thermal power constant during its entire operating period, maximizing its capacity factor and value. The technology provides dispatchable power at a scale that can make a difference in efforts to decarbonize electricity and stabilize grids with high penetrations of renewables.

The Natrium reactor builds on existing nuclear energy plant technology but differs from existing plants in several ways.

• Smaller. The Natrium plant is much smaller than most conventional nuclear plants, which are around 1,000 megawatts in size. It is easier and faster to construct, and more cost effective for utility customers.
• Safer. By using sodium near atmospheric pressure, the Natrium plant both enhances safety and can reduce costs by using a much simpler architecture.
• Integrates with renewables. The reactor’s heat can be stored in the molten salt tanks, much like a large battery. The energy storage system can store more energy than the largest battery storage system currently deployed on the grid. This enables a Natrium plant to operate as a baseload power source or as a flexible, load-following system to support grids with variable-output renewables.

The Natrium technology is an integrated energy system powered by a sodium fast reactor. With energy storage and flexible power production, the technology offers abundant clean energy at a competitive cost. The Natrium technology is the best option for deploying advanced nuclear power in a world with an ever-growing mix of renewable energy sources because it:

• Simplifies construction and architecture compared to previous reactor types
• Offers a cost-competitive, flexible technology that supports load following, energy storage and industrial process heat applications
• Brings step-change improvements in fuel and operational costs
• Provides a utility-scale decarbonization solution that can make a meaningful impact on efforts to mitigate climate change

The Natrium technology has been designed to reduce complexity, cost and construction schedule. The key innovation relative to past reactors is the novel architecture that separates and simplifies major structures. The power block, which represents most of the plant, can be constructed and operated without the need for special nuclear grade equipment or construction, as there are no safety functions provided by that part of the plant.

In addition, the compact low pressure reactor system with passive vessel cooling significantly reduces space and the amount of nuclear-grade concrete required. In fact, on a per MWe basis, it uses 80% less nuclear-grade concrete compared to today’s large reactors.

The Natrium technology uses a sodium fast reactor to produce heat, which can be used to generate electricity immediately or be contained in thermal storage reserves for hours. This innovative combination with energy storage allows the reactor to operate at a steady state, supporting the increased use of renewables and helping utilities capture more daily electricity revenue. As more and more renewables are integrated into the grid, the demand for gigawatt-hour-scale energy storage will continue to increase.

The team chose liquid metal sodium as the reactor coolant because it has several excellent characteristics that include:

• Operation at atmospheric pressure: Sodium is a high-temperature liquid with a boiling point that is far higher than temperatures experienced during operations. This allows operation near atmospheric pressure, meaning that the reactor can use easier-to-fabricate metallic structures. This also avoids the expense of large, pressure-retaining equipment and civil structures.
• Exceptional heat transfer: Because sodium is a liquid metal, it has exceptional heat transfer. This results in high power density, meaning that large amounts of heat can be generated and harnessed with a small footprint. The main driver for the heat transfer is the coolant’s ability to transfer heat, its thermal conductivity, which is three times higher than stainless steel, the reactor structural material. High power density, combined with the inertia of the sodium pool configuration, leads to a smaller heat supply and heat removal systems. The high heat transfer of the reactor coolant, even under natural circulation, enables direct heat removal from the surface of the vessel by air. Heat removal from the vessel surface is responsible for a major reduction in equipment and structures versus previous nuclear technologies.
• High Temperature: The high-temperature capability of the sodium drives eight percentage points higher thermal efficiency as compared to conventional light water reactors. It also enables process heat applications for refining and petrochemical processes, chemicals, forest products and other sub-sectors traditionally fueled by natural gas. The high temperature output allows for the use of an economic and proven thermal storage system.
• Practicality: Sodium is a practical coolant that supports longevity and minimal maintenance on components. It has high-temperature capability. It maintains the high energy of the neutrons without degrading. Maintenance of sodium quality is a simple established process. It also doesn’t corrode materials, so operators can avoid corrosion-driven maintenance of permanent reactor structures.
• Extensive experience: Building on the scientific community’s more than six decades of experience using sodium, this technology can be commercialized quickly enough to make a difference in decarbonization efforts.

The Natrium™ technology features a 345 MWe sodium-cooled fast reactor with a molten salt-based energy storage system. The storage technology can boost the system’s output to 500 MWe for more than five and a half hours when needed. Because the Natrium plant’s storage technology can boost the system’s output from 345 MWe to 500 MWe when needed, the technology will be able to power approximately 250,000 to 400,000 homes depending on need.

Efforts to demonstrate the Natrium reactor are underway as part of the U.S. Department of Energy’s (DOE) Advanced Reactor Demonstration Program (ARDP). DOE is supporting a variety of U.S. advanced reactor designs, through the ARDP, that will expand access to clean energy, create new U.S. jobs and offer significant improvements over today’s technology. The DOE’s ARDP will speed the demonstration of advanced reactors through cost-shared partnerships with U.S. industry.

There are three pathways as part of DOE’s ARDP. TerraPower’s Natrium technology was selected as one of two awardees for the advanced reactor demonstrations pathway along with X-energy. The goal of the demonstration pathway is to test, license and build operational advanced reactors within seven years. Under this public-private partnership, the Department of Energy authorizes up to $2 billion for the Natrium project and TerraPower and partners will match this investment dollar for dollar. Other pathways that are part of the DOE’s ARDP are to support the risk reduction and development of reactor technologies that have a longer time horizon to commercial development.

A nuclear reactor demonstration project is intended to prove out the new technology’s design, licensing, construction and operational features. The ARDP is a precedent-setting, public-private partnership to support such demonstration efforts. Notably, sodium-cooled fast reactors, like the Natrium reactor, have the highest technology readiness levels of any advanced non-light water reactor. The goal of demonstrating the Natrium technology is to enable the commercialization of this new source of abundant and affordable clean energy in time to help meet climate goals.

At the end of the project, the Natrium demonstration will be a Nuclear Regulatory Commission (NRC)-licensed, grid-scale reactor entering commercial service.

Over the past century, technology innovation and U.S. economic prosperity have been mutually dependent. Research and development are necessary to create technologies that have market potential and can improve public welfare.

In the advanced nuclear sector, the successful development and commercialization of a reactor rely heavily on government policy and regulation. As a result, government involvement helps to stimulate innovation and supports continued private investment. Advanced reactor demonstrations build on a long history of public- and private-sector cooperation in the United States. Such efforts resulted in the development of railroads, the internet, the space program and even the light water reactor technology used at today’s nuclear energy plants.

The Naughton power plant currently uses water supplied by a pipeline that draws from the Hams Fork River and the Viva-Naughton Reservoir. As the existing plant is retired, the Natrium plant will leverage this existing infrastructure as its water source. The existing infrastructure includes a cooling tower so there is no need to return heat to local bodies of water. This water will be used to create and cool the steam created during electricity generation. Water usage for the Natrium plant is expected to be similar or less than the existing coal plant.

Several of the bodies of water near the current Naughton plant are associated with coal operations and will not be utilized by Natrium technology.

According to project estimates, approximately 1,600 workers will be needed for construction at the project’s peak. Once the plant is operational, approximately 200-250 people will support day-to-day activities, including plant security. Those jobs will be in the community for many decades to come once the reactor is operational.

We are excited to partner with Wyoming’s community colleges and universities to train the skilled workers we will need to build and operate the Natrium™ plant, and ensure that young people can gain the skills necessary to work in the nuclear field for decades to come. We’ve begun engagement with workforce development officials and look forward to partnering with the universities and community colleges in Wyoming as well.

There are many similarities between running a coal plant and the power system that will generate electricity in the Natrium system. While there are some jobs unique to nuclear, there are many other jobs where the skills possessed by the existing coal workforce are transferable. One of the reasons TerraPower is building at the site of a retiring coal plant is to utilize and train the workforce in these communities on the Natrium system.