Construction has officially begun on the Kemmerer Unit 1 Natrium nuclear project in Kemmerer, Wyoming, developed by TerraPower. The milestone marks the start of on-site construction for what the company describes as its flagship advanced reactor facility.
The project follows the issuance of a construction permit by the U.S. Nuclear Regulatory Commission and comes after years of design work and site preparation at the greenfield location.
The Natrium plant will feature a 345-megawatt sodium-cooled fast reactor paired with a molten salt energy storage system. The integrated storage component allows output to increase to up to 500 megawatts during periods of peak demand.
The design is intended to provide steady baseload generation while also offering flexible output when required.
Construction and workforce
At peak construction, the project is expected to employ around 1,600 workers. Once operational, it is projected to support approximately 250 permanent jobs at the facility.
Engineering and construction responsibilities are being led by Bechtel, working alongside TerraPower under a project delivery model that incorporates digital engineering systems and staged construction execution.
Project development framework
The facility is being developed under the U.S. Department of Energy’s Advanced Reactor Demonstration Program, which supports private-sector deployment of advanced nuclear designs.
U.S. Department of Energy is supporting the program alongside industry partners involved in reactor design, construction, and equipment supply.
The project is located in Lincoln County, Wyoming, and represents the first phase of TerraPower’s Natrium demonstration deployment at the site. Initial site work began earlier, including preparation of non-nuclear infrastructure before the start of reactor construction.
The Kemmerer Unit 1 project has moved from preparation into full construction, advancing TerraPower’s first Natrium reactor toward operational development. Additionally, project follows other major U.S. energy developments, including West Virginia’s Wolf Summit Power Plant construction in Harrison County.
Kemmerer Unit 1 – Factsheet
Location: Kemmerer, Lincoln County, Wyoming, United States
Project Type: Advanced nuclear power plant (sodium-cooled fast reactor with energy storage)
Developer: TerraPower
Engineering, Procurement & Construction (EPC): Bechtel
Regulatory Authority: U.S. Nuclear Regulatory Commission (construction permit issued)
Government Program Support: U.S. Department of Energy – Advanced Reactor Demonstration Program (ARDP)
Capacity & Technology
- Reactor Output: 345 MW (base generation)
- Peak Output: Up to 500 MW (with energy storage system)
- Technology: Sodium-cooled fast reactor (Natrium design)
- Energy Storage: Molten salt-based storage system for load shifting and peak support
Construction Status
- Construction officially commenced: April 23, 2026
- Site preparation: Previously initiated (non-nuclear infrastructure)
- Stage: First utility-scale advanced nuclear build phase underway
