US-based TerraPower is replacing Bechtel as the lead engineering, procurement, and construction (EPC) contractor for its $4bn Natrium advanced nuclear reactor project near Kemmerer, Wyoming. TerraPower and Bechtel were unable to reach an agreement on the terms and pricing for the next major phase of the project.
The Kemmerer project, heavily backed by Microsoft co-founder Bill Gates and co-funded by a Department of Energy (DOE) commitment, is promoted as a milestone for next-generation nuclear energy. Natrium consists of a 345 MWe sodium-cooled fast reactor with an integrated molten salt-based energy storage system that can ramp up the plant’s output to 500 MWe for over five hours to meet peak grid demand.
TerraPower named Bechtel as its plant design, licensing, procurement, and construction partner in 2020. Bechtel was integrated directly into TerraPower’s federal grant application for the DOE Advanced Reactor Demonstration Program. The project was awarded $2bn in federal funding, which TerraPower matched.
From 2021 Bechtel worked side-by-side with TerraPower during the early design stages. The goal was to build a nuclear island separate from an energy storage island using modular construction methods and Bechtel’s digital suite of tools to lower costs. In August 2025, Bechtel and TerraPower began constructing the Kemmerer Training Centre (KTC) to prepare operator teams.
In June 2024, the partners celebrated the groundbreaking ceremony at the Kemmerer, Wyoming site. Bechtel began executing early infrastructure work. In late 2025, Bechtel supported TerraPower through huge regulatory hurdles, helping secure approval for the Environmental Impact Statement in October and the Final Safety Evaluation from the Nuclear Regulatory Commission (NRC) in December.
NRC issued the formal construction permit in April 2026 – the first ever issued for a commercial non-light-water reactor in the USA. Bechtel mobilised construction crews and transitioned into full field execution on Kemmerer Unit 1.
After several years, negotiations stalled when trying to lock down the exact financial and structural scope of the full, long-term EPC contract. While Bechtel is stepping away as the overall lead contractor, they are not abandoning the site instantly. They are staying on-site to finish building the exterior enclosure of the Sodium Test & Fill Facility to guarantee an orderly handover.
The split
The split between TerraPower and Bechtel stems from an inability to reach an agreement on commercial terms and pricing for the next major phase of the Natrium Demonstration Project. While initial development milestones were completed under a limited early scope, the two companies reached an impasse when attempting to contractually lock in risk allocations and pricing for the heavy nuclear construction phases.
Large-scale, first-of-its-kind nuclear infrastructure projects carry huge financial and execution risks. The split suggests that Bechtel wanted to price those risks into the contract to protect itself from cost overruns, while TerraPower wanted a lower price or a different distribution of liability.
Because the project is being bid out in separate phases, Bechtel likely submitted a price for the heavy nuclear construction phase that reflected the immense complexity of building a sodium-cooled fast reactor. TerraPower, having found a mismatch in those commercial numbers, then opted to rebid the contract rather than accept Bechtel’s risk-adjusted pricing.
TerraPower stated that Bechtel’s departure will not impact the construction schedule. The plant is still on track for construction completion by 2030 and commercial operations by 2031. However, the timeline is a serious concern. The project has already slipped. The original operational target was 2028.
Historically, the nuclear industry is plagued by huge delays and cost overruns when debuting new technology. Navigating a completely new supply chain and construction technique for a sodium-cooled fast reactor without hitting unexpected bottlenecks is unlikely.
While TerraPower has not announced a shortlist for replacing Bechtel, there are several possible candidates based on their existing strategic alliances with TerraPower, large nuclear footprints, or active involvement in the advanced nuclear sector.
TerraPower already has established global relationships with heavy-hitting EPC firms intended to deploy subsequent Natrium plants. However, construction will not stop while a replacement is found. TerraPower is temporarily using commercial-grade support firms and its existing subcontractor teams that were already working on-site under Bechtel to try to meet the 2030 timeline while a new lead contract is negotiated.
