TerraPower Brand Guidelines: Bill Gates’s Reactor Company & the Natrium Plant in Kemmerer

A Bellevue lab bet on fast reactors.

TerraPower began inside Intellectual Ventures, the invention company in Bellevue, Washington. English Wikipedia says Intellectual Ventures launched TerraPower as a spin-off in 2006 to model and commercialise a traveling wave reactor, a fast-reactor concept meant to run largely on depleted uranium. TerraPower calls itself the first spin-out of Intellectual Ventures, and says it was founded by Bill Gates and a group of like-minded people; Gates has chaired its board since 2006, the company says, with Intellectual Ventures founder Nathan Myhrvold as vice chairman. Chris Levesque is president and chief executive.

Gates gave the idea a public stage in his 2010 TED talk, Wikipedia notes. The first route to a prototype ran through China: in September 2015 TerraPower signed an agreement with the China National Nuclear Corporation to build a demonstration traveling wave reactor in Fujian province. English Wikipedia says the project was abandoned in January 2019, after the US government placed limits on nuclear technology transfer to China.

Japan was an earlier point of contact. English Wikipedia says TerraPower executives and Gates visited Toshiba’s Yokohama and Keihin factories in November 2009 and signed a non-disclosure agreement with the company that December, because Toshiba had developed an ultracompact reactor, the 4S, some of whose technology was considered transferable to TerraPower’s design. In December 2011, Wikipedia adds, India’s Reliance Industries bought a minority stake through a subsidiary.

The company then shifted its weight to a different design. Gates remains a principal investor, through his Cascade Investment vehicle, according to Wikipedia, which also lists a 2022 investment round co-led by South Korea’s SK Group. TerraPower says the Korean utility Korea Hydro & Nuclear Power joined its investor base in January 2026.

Natrium and the chloride salt experiment.

TerraPower’s main product is Natrium, a sodium-cooled fast reactor paired with a molten-salt energy store. World Nuclear News described it in March 2026 as a 345-megawatt reactor whose storage system lets output rise to 500 megawatts for periods, and as a technology of TerraPower and GE Vernova Hitachi Nuclear Energy. TerraPower’s own material divides the plant into a “nuclear island” and an “energy island.”

In October 2020 the US Department of Energy chose TerraPower for its Advanced Reactor Demonstration Program, with Bechtel as design, licensing and construction partner, English Wikipedia says. In June 2021 TerraPower and the utility PacifiCorp announced plans for a joint Natrium plant, and on 16 November 2021 the coal town of Kemmerer, Wyoming, was picked from four Wyoming candidates near retiring fossil-fuel plants.

The permit came next. TerraPower filed its construction permit application with the NRC in March 2024, and non-nuclear building work began in June 2024. On 4 March 2026 the NRC approved the construction permit for Kemmerer Unit 1; World Nuclear News reported that the NRC called it the first non-light-water reactor approved for construction in more than 40 years. TerraPower announced on 23 April 2026 that construction had begun. The project is expected to be complete in 2030, World Nuclear News said, and a TerraPower subsidiary must still obtain a separate operating licence before the plant can run.

English Wikipedia adds that in September 2026 TerraPower and Bechtel said they would end their development relationship on the Kemmerer contract, with Bechtel finishing the sodium test and fill facility and TerraPower seeking a new contractor.

The company’s second reactor line is a molten chloride fast reactor. Wikipedia says TerraPower and Southern Company agreed in February 2022 to build a small test unit, the Molten Chloride Reactor Experiment, at Idaho National Laboratory, which announced in December 2025 that it had fabricated the first batch of chloride salt fuel for it.

Design and documentation.

Nuclear companies sell to a small number of buyers — utilities, governments and regulators — over very long timescales, and their imagery tends to reflect that. Corporate pages and reports often return to the same few scenes: cooling towers and reactor domes photographed under clear skies, turbine halls in clean, even light, and wide views of plants set against water or open country.

Newer reactor designers, many of which have not yet built a commercial plant, lean on renders instead. Small modular plants appear as low, compact buildings in green landscapes, sometimes beside a town or a data centre, with no smoke and few people. Large-reactor vendors show construction sites, cranes and heavy components such as reactor vessels and steam generators on the move, a way of picturing scale and progress at once.

People appear mostly as engineers in hard hats and overalls, inspecting a weld, reading a control-room screen or handling fuel. Two images recur across the trade: the blue Cherenkov glow of a spent-fuel or research-reactor pool, caused by charged particles travelling through water faster than light does in it, and ceramic fuel pellets held in a gloved hand. Both are used to make an invisible process visible.

The industry also presents itself in person, at trade gatherings such as the World Nuclear Exhibition and the meetings of the American Nuclear Society, where stands, renders and scale models carry much of the message. The companies in this guide range from Framatome, founded in 1958, and Urenco, set up by treaty in the early 1970s, to much younger reactor designers, and their visual languages vary just as widely.

Isotopes, overseas plans and a Wyoming build.

Beyond Wyoming, TerraPower’s plans are still plans. World Nuclear News reported in March 2026 that the technology company Meta had announced funding to support up to eight Natrium units in the United States: two with delivery as early as 2032, and rights to energy from up to six more targeted for 2035. In Britain, TerraPower says it launched TerraPower UK and began Step 1 of the Generic Design Assessment for Natrium on 16 June 2026, after the reactor was accepted into that regulatory process in February 2026. None of these reactors had been built at the time of writing.

The company has a second line of business in isotopes. TerraPower Isotopes, an affiliate, works on extracting actinium-225, a radioisotope the company says is for medical use, and it says it broke ground on a manufacturing facility in Philadelphia on 6 May 2026.

On its own site the company groups its work under two names, Natrium and TerraPower Isotopes, and presents the Natrium plant through its two named halves, the nuclear island and the energy island.

For a design guide, TerraPower shows how a privately backed engineering company carries one product name, Natrium, from a lab concept to a permitted construction site. Compare GE Vernova, whose joint venture with Hitachi shares the Natrium technology, and Bechtel, its first construction partner at Kemmerer. For this guide we use a sagebrush green, plateau sand and a molten amber with a sans, an unofficial interpretation; no product or logo is reproduced.

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