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Last year, TerraPower was excited to announce Kemmerer, Wyoming as the location for our first NatriumTM plant, a technology that we developed with GE Hitachi. This 345 MWe sodium fast reactor also features an energy storage system that can boost output to 500 MWe during peak demand. Today, this innovative design is leading the pack of proposed advanced reactors with a projected in-service date within this decade.

The opportunity to build near one of PacifiCorp’s retiring coal plants in Wyoming, and add our technology to Kemmerer’s rich history of energy production, is something we continue to be proud of. Wyoming has a lot to offer as a national energy leader 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.


Large, first-of-a-kind, energy generation projects like the Natrium project take years to come to fruition. There is an incredible amount of work that goes into meeting each milestone long before a plant is operational.

For the first three years of this project, TerraPower is focused on advancing the plant design and submitting the construction permit application to the U.S. Nuclear Regulatory Commission (NRC). We have completed our first year of planning work and have met all our internal milestones.

TerraPower currently has more than 600 engineers working diligently on the final design and development of the Natrium reactor. This design work will generate the plant specifications that will enable TerraPower and our contractors to outline our exact needs during the procurement phase of the project.  


Crews also have been on the site of the future Natrium plant in Kemmerer for the last several months conducting a subsurface, or geotechnical, investigation. The property, which is owned by PacifiCorp, is a greenfield site without a lot of information about what’s beneath the surface.

Crews drilled more than 100 boreholes to evaluate the underlying soil and rock. These investigations are done prior to most construction projects to help understand things such as the makeup of the soil, the depth of the bedrock and the makeup the local water table. Soil and rock samples from various depths will be sent to specialty laboratories for testing to evaluate the material properties.  One of the labs TerraPower is working with is the University of Wyoming’s geology laboratory. 

All of the information from this process will be used in the design and construction of the project. It will contribute to helping build a stable and safe foundation for Natrium’s two main operational areas: the nuclear island, where the reactor will be, and the energy island, where the molten salt energy storage system, turbine and generating facilities will be.

TerraPower will also be using this information in our NRC permit application. The NRC requires a detailed site investigation to establish the geologic and geotechnical conditions that could affect the design, performance and safety of the plant.


Field activities in Kemmerer are scheduled to be complete in early July 2022 and the trailers onsite will be removed. Several groundwater monitoring wells will remain in place for long-term groundwater monitoring.

Once this work is completed, our team’s attention turns to laboratory testing and analysis. Early construction activities will likely begin in 2024.

There is still much work to be done. Progress to date has been encouraging and we are grateful for the continued support we receive from Kemmerer and the State of Wyoming.