TerraPower has officially broken ground on Kemmerer Unit 1 in Wyoming, set to become America’s first utility-scale advanced nuclear power plant.

The April 23 announcement marks the start of full construction on the Natrium reactor, a 345-megawatt sodium-cooled fast reactor paired with a molten salt-based energy storage system that can ramp output to 500 megawatts for over five hours to handle peak demand.

The project sits near a retiring coal plant in Kemmerer, making it Wyoming’s first commercial nuclear generating station. Non-nuclear site preparation began in June 2024 after years of engineering and regulatory hurdles. 

The DOE’s Advanced Reactor Demonstration Program provided public-private backing, with Bechtel handling engineering, procurement and construction, and GE Vernova Hitachi Nuclear Energy contributing reactor technology. 

With commercial operations targeted around 2030, The U.S. may finally get on the board for having a utility scale reactor under construction…

As we reported when the NRC granted the construction permit in March, this step represents the start of actual nuclear facility construction. Up until now, all the work at the site has been for the non-nuclear systems. We also covered TerraPower’s agreement with Meta for up to eight Natrium plants by 2035 to support data center power needs.

TerraPower President and CEO Chris Levesque described the moment as one the industry has been working towards for a generation. “We’re not just breaking new ground on a first-of-a-kind nuclear plant in Wyoming; we’re building the next generation of America’s energy infrastructure.”