Bechtel, TerraPower’s engineering, procurement, and construction partner, broke ground on the project in mid 2024. It is set to employ about 1,600 workers for construction at project peak in an estimated five-yeartimeline.

North America’s Building Trades Unions on March 3 said it signed a project labor agreement with TerraPower for construction of the Natrium reactor, marking “a massive step forward for America’s nuclear industry,” its President Sean McGarvey said in a statement.

UPDATE: TerraPower announced on March 13 a "strategic alliance" with professional services firm KBR it describes as a "long-term collaboration" to commercialize and deploy Natrium reactors in North America, the U.K. European Union "and beyond." 

The firms' agreement "lays the groundwork for establishing a replicable contracting framework for rapid deployment of Natrium reactors that reduces financial risk and ensures cost transparency, the developer said. "Together, TerraPower and KBR will work closely with utilities and energy off-takers to implement the new framework." TerraPower said it "will lead efforts related to engineering, research and development, supply chain and regulatory activities," noting that KBR "may provide Engineering, Procurement and Construction Management services including design, commissioning and financial leadership through its unique business model." 

The alliance "will also support planning and strategy for early project development and site characterization activities, as well as communication strategies for governmental cooperation to promote Natrium on a global scale," TerraPower said. “This agreement will build even greater certainty into the Natrium technology’s supply chain, project management and overall business model.” KBR said the link comibines its "proven program management and project delivery capabilities and TerraPower’s expertise in advanced nuclear technology."

DOE also said it plans to authorize funds for site preparation and support infrastructure work, including non-structural backfill, construction of multiple buildings, installation of underground services, laying foundations, installation of stormwater management ponds and establishing temporary power. 

Construction of support infrastructure is set to begin this month, but construction of the nuclear unit will not begin until the U.S. Nuclear Regulatory Commission issues a construction permit, which is expected to come in Sept. 2026 after it completes an expected 18-month long environmental impact statement and a record of decision. The approved infrastructure construction would not involve radioactive material or nuclear safety-related systems, “and no safety-related structures would be built,” DOE said.

The commission said in late February that it completed its draft safety evaluation for the plant and expects to complete the final safety evaluation in June 2026, needed before a construction permit can be granted. 

The proposed infrastructure funding would come under DOE’s seven-year, $2-billion matching agreement signed in 2020 as part of its Advanced Reactor Demonstration Program. 

TerraPower said in January that it received approval from Wyoming authorities for construction and operational activities that are not under commission jurisdiction.

The state approval allows construction of the energy island that will house the molten-salt energy storage tanks and turbines. “With this permit complete, TerraPower will continue its aggressive construction schedule; and plans to start construction on both the Kemmerer Training Center and the energy island in 2025, as well as continue work on the sodium test and fill facility that began in 2024,” the company said.

The state permit was the first by any state awarded to a commercial-scale advanced nuclear project. “The regulatory process to bring new nuclear plants to fruition is robust, and our team has been working relentlessly to successfully maneuver through a complicated, multi-jurisdictional environment to bring the first Natrium plant to market,” TerraPower CEO Chris Levesque, said in a statement. 

TerraPower is the only advanced nuclear developer that has submitted a permit application for a commercial advanced reactor to the commission, done last year. The unique Natrium design, a collaboration between TerraPower and GE Hitachi Technology, allows the company to start non-nuclear construction onsite during the NRC review, the company said. 

Among firms working on the project are Spanish engineerin Equipos Nucleares SA to produce the reactor head; South Korea's Doosan Corp. to supply the reactor core barrel, guard vessel and internal supports and HD Hyundai to manufacture the reactor vessel; Western Service Corp. to provide the software platform and engineering services for the Natrium engineering simulator; and James Fisher Technologies to design and build an injection casting furnace system to demonstrate the basic functionality of the injection casting process. BWXT Canada Ltd. will design the reactor intermediate heat exchanger, while Curtiss-Wright Flow Control Service LLC will develop the reactor protection system.

Expected to be completed by 2030, the Natrium plant will be a “fully functioning commercial power plant,” TerraPower said. Its energy storage system allows the plant to integrate easily with renewable resources, said the developer, which was founded by former Microsoft CEO Bill Gates in 2008.

The company estimates that 250 people will support day-to-day activities, including plant security, once the plant operates. 

In mid-February, TerraPower and nVision Energy, an affiliate of utility-scale energy project developer NOVI Energy, agreed to establish a framework to deploy a model for developing Natrium reactor and energy storage system plants across the U.S.

In January, TerraPower and data center developer Sabey Data Centers signed a memorandum of understanding to develop a strategic collaboration to leverage Natrium plants into the developer's current and future data center operations.