Natrium® Advanced Reactor Demonstration Project
Kemmerer, Wyoming · TerraPower / Bechtel · U.S. DOE Advanced Reactor Demonstration Program
A first-of-a-kind plant on the Wyoming high plains
Natrium is TerraPower's sodium-cooled fast reactor paired with a molten salt energy storage system, sited near Kemmerer, Wyoming, adjacent to a retiring coal plant. The project is one of two demonstration reactors selected by the U.S. Department of Energy's Advanced Reactor Demonstration Program, with Bechtel serving as the engineering, procurement, and construction partner.
The plant is organized into a nuclear island and an energy island. Because the storage system decouples the reactor from the turbine, non-nuclear early works, including the Test & Fill Facility, could begin construction while the reactor buildings moved through NRC licensing. The site broke ground in June 2024.
The NRC construction permit for the plant was the first ever issued in the United States for a commercial non-light-water reactor. Architectural design basis documentation supporting that application is part of the work described on this site.
| Owner | TerraPower, LLC |
|---|---|
| EPC | Bechtel |
| Program | U.S. DOE Advanced Reactor Demonstration Program |
| Location | Kemmerer, Lincoln County, Wyoming |
| Technology | Sodium-cooled fast reactor with molten salt energy storage |
| Role | Architectural Designer, Bechtel (Jun 2022 – present). Architectural lead for the Reactor Auxiliary Building, Fuel Auxiliary Building, and Test & Fill Facility |
| Phases | Design development · NRC construction permit documentation · Construction documents · Construction administration |
Architectural lead for three buildings
Test & Fill Facility
Energy island, early-works package. Approximately 125 × 220 ft in plan and 167 ft tall. Carried through field construction to completion of the exterior enclosure, responding to RFIs and field conditions ahead of full site mobilization in April 2026.
Reactor Auxiliary Building
Nuclear island. Complete architectural package translating nuclear safety classification and radiological zoning into buildable plans, sections, elevations, and life safety documentation.
Fuel Auxiliary Building
Nuclear island. Architectural design and multi-discipline coordination reconciling equipment layouts and structural systems with the building enclosure.
Beyond the three buildings
Architectural detail library
Established and maintain the project's architectural detail library, giving every building team on the multi-building program a single vetted source for typical conditions.
3D plant walkthrough
Built the plant's comprehensive 3D walkthrough in Twinmotion. Displayed on site at the Kemmerer groundbreaking ceremony and adopted as the client-facing visualization for stakeholder engagement and business development.
NRC construction permit
Contributed architectural design basis documentation to the construction permit application, the first issued in the U.S. for a commercial non-light-water reactor.
Cross-discipline coordination
Resolved design conflicts across Plant Design, Civil, Structural, Mechanical, and Nuclear Engineering to keep designs constructible and compliant.
Publicly released views of the plant
