Bill Gates' advanced nuclear company building America's first Natrium plant
HQ: Bellevue, WA, United States | Founded: 2006 | Employees: Not disclosed in reviewed sources | Stage: Private, project-financed; $650M raised June 2025 (valuation undisclosed); Kemmerer Unit 1 under construction with ~$4B budget | Website: https://www.terrapower.com
TerraPower, LLC was founded in 2006 by Bill Gates and a group of scientists and engineers to rethink nuclear power using modern computation and materials, with Gates serving as chairman and Nathan Myhrvold as vice chairman. Its original concept was the traveling wave reactor, a design intended to run for decades on depleted uranium without enrichment or reprocessing; after a proposed Chinese demonstration project collapsed in 2019 over technology-transfer restrictions, the company pivoted its commercial focus to Natrium, a sodium-cooled fast reactor paired with molten-salt energy storage. Chris Levesque, a former nuclear submarine officer, is president and CEO, and the company is based in Bellevue, Washington.
Natrium is the product that matters. The reactor produces 345 MWe of nuclear heat, and an integrated molten-salt storage system can absorb that energy and release it to lift output to roughly 500 MWe when demand peaks — behaviour that lets a nuclear plant follow load like a gas peaker rather than run flat out. The design was selected by the U.S. Department of Energy in October 2020 under its Advanced Reactor Demonstration Program, which covers roughly half the cost of a demonstration plant, capped at about $2B. In November 2021 Kemmerer, Wyoming was chosen as the site, next to a retiring coal plant owned by PacifiCorp, which operates as Rocky Mountain Power and intends to buy the power.
Construction has been methodical and is now real. TerraPower broke ground in June 2024 on the site's Sodium Test and Fill Facility and filed its construction permit application in March 2024. The NRC issued that permit on 4 March 2026 — the first construction permit for a non-light-water commercial reactor in U.S. history — and physical construction began in April 2026, with completion targeted around 2030-2031. The project budget is approximately $4B, with the DOE supplying about half, Gates contributing roughly $1B, and private capital covering the rest.
Funding history stretches back further than the current hype. Khosla Ventures reportedly invested $35M in 2010, India's Reliance Industries took a minority stake in 2011, and in 2022 TerraPower raised $830M — co-led by SK Inc and SK Innovation, which invested $250M, alongside Gates — a round reported at around a $3.8B valuation. In June 2025 it closed a further $650M at an undisclosed valuation to fund construction, months before Meta agreed to fund two additional Natrium plants by 2032 with rights to power from up to six more by 2035. The company is also commercializing its nuclear science elsewhere: TerraPower Isotopes announced a $450M actinium-225 production facility in Philadelphia in March 2026, and TerraPower entered the UK's Generic Design Assessment process in 2025, beginning Step 1 in June 2026.
TerraPower is the most substantial bet in the advanced-nuclear revival: a first-of-a-kind reactor design, a site in Kemmerer, Wyoming, a roughly $4B construction budget half funded by the U.S. Department of Energy, and the first NRC construction permit ever granted for a non-light-water commercial reactor. For a company founded in 2006, that is both the payoff for two decades of patience and the beginning of the hardest phase, because building the first Natrium plant at cost and on schedule is what will determine whether TerraPower becomes a reactor vendor at scale or a very expensive one-off.
The demand side arrived faster than the supply side. AI data centers turned electricity into a strategic bottleneck, and in January 2026 Meta agreed to fund two Natrium plants to be operating by 2032, with rights to electricity from up to six more by 2035 — up to 2.8 GW of capacity. That is precisely the anchor customer every advanced reactor company needs, and it validates TerraPower's pitch that a sodium-cooled fast reactor with thermal storage behaves like a dispatchable plant rather than a baseload-only one. Gates remains chairman and a principal funder through Cascade Investment; total private capital raised includes $830M in 2022 and $650M in 2025.
The risks are execution and fuel. In September 2026 Bechtel and TerraPower parted ways on the engineering, procurement and construction contract and TerraPower said it would rebid the role on the $4B project — a significant change on a first-of-a-kind build, even if framed as a cost-competition exercise. Natrium also depends on high-assay low-enriched uranium (HALEU), a fuel supply chain the U.S. is still building. Add HALEU availability, NRC timelines for the operating licence, competition from Oklo, X-energy, NuScale and gas turbines, and the fact that no advanced reactor yet runs commercially in America, and TerraPower's value hinges on proving that Natrium can be built repeatedly, not just once.
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