TerraPower announced on April 23, 2026, that it has commenced official construction on Kemmerer Unit 1, a Natrium advanced nuclear power plant located in Kemmerer, Wyoming. The U.S. Nuclear Regulatory Commission had previously issued the construction permit for the project, which TerraPower describes as the first utility-scale advanced nuclear power plant in the United States and Wyoming’s first commercial nuclear generating station. While ground was broken on the greenfield site in June 2024 and work began earlier on non-nuclear support facilities, this announcement marks the formal start of plant construction with 1,600 workers mobilized to the site.
What it means
The Kemmerer Unit 1 facility will house a 345-megawatt sodium-cooled fast reactor. According to TerraPower, the integration of energy storage allows the plant to boost its output capacity to 500 MW, providing enough electricity for approximately 400,000 homes. The project is being developed through the U.S. Department of Energy’s Advanced Reactor Demonstration Program (ARDP). Bechtel serves as the engineering, procurement and construction contractor for the build. Once operational, the plant is expected to employ 250 full-time staff members.
The Natrium reactor technology is a joint development between TerraPower and GE Vernova Hitachi Nuclear Energy. Rocky Mountain Power supports the project as part of its energy strategy. TerraPower also holds an agreement with Meta for up to eight additional Natrium plants by 2035. Chris Levesque, president and CEO of TerraPower, said in a release that the company is building “the next generation of America’s energy infrastructure.” Wyoming Governor Mark Gordon stated that the start of construction “marks a major milestone not just for Wyoming, but for the future of American energy.”
Key facts
- Kemmerer Unit 1 location: Kemmerer, Wyoming
- Construction start date: April 23, 2026
- Groundbreaking date: June 2024
- Reactor type: Natrium sodium-cooled fast reactor
- Base capacity: 345 MW
- Boosted capacity with storage: 500 MW
- Homes served (boosted): 400,000
- Construction workforce mobilized: 1,600 workers
- Expected operational staff: 250 full-time employees
- Contractor: Bechtel
- Funding program: U.S. Department of Energy Advanced Reactor Demonstration Program (ARDP)
- Future pipeline: Agreement with Meta for up to eight plants by 2035
Source: TerraPower news release (PR Newswire)