The story
Founded by Bill Gates and Nathan Myhrvold in 2008.1
In September 2015, TerraPower signed an agreement with state-owned China National Nuclear Corporation to build a prototype 600 MWe Travelling Wave Reactor unit at Xiapu in Fujian province, China, from 2018 to 2025. Commercial power plants, generating about 1150 MWe, were planned for the late 2020s. In January 2019 it was announced that the project had been abandoned due to technology transfer limitations placed by the Trump administration.
In October 2020, the company was chosen by the United States Department of Energy (DOE) as a recipient of a matching grant totaling between $400 million and $4 billion over the ensuing five to seven years to build a demonstration reactor using their Natrium design as part of the DOE's Advanced Reactor Demonstration Program.
In June 2021, TerraPower and PacifiCorp, a subsidiary of Warren Buffett's Berkshire Hathaway Energy, announced plans to build a joint Natrium reactor.
Four cities in Wyoming were considered for the demonstration reactor that were affected by the closure of fossil-fuel power plants: Gillette, Kemmerer, Glenrock and Rock Springs. PacificCorp does business in Wyoming as Rocky Mountain Power and has a coal power plant in each of the candidate locations. It was announced November 16, 2021 that Kemmerer had been selected.
In 2024, TerraPower selected Kemmerer as the site for a 345 MWe Natrium reactor. The company submitted their application for a nuclear construction permit for Kemmerer Unit 1 to the United States Nuclear Regulatory Commission (NRC) on March 28, 2024.
The power station is designed to consist of two adjacent parts: an "energy island" and a "nuclear island". In June 2024 the site broke ground, beginning construction of the facility's Sodium Test & Fill Facility. Cost estimates were $4 billion, with the DOE supplying half, and Bill Gates contributing $1 billion.
In April 2025, TerraPower notified the British Office for Nuclear Regulation that it intends to enter the Generic Design Assessment process for its Natrium reactor and the company announced in June 2026 that it had begun Step 1 of the assessment.
In October 2025 the Kemmerer project completed its final Environmental Impact Statement (EIS), finding no adverse impacts. The NRC issued the construction permit for Kemmerer Unit 1 on March 4, 2026. It was the first construction permit for a non-LWR issued by the NRC. Reactor construction began in April 2026.
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In January 2026, Meta announced an agreement to fund two Natrium reactors to be built by 2032, and to give Meta the rights to electricity produced by up to six more Natrium reactors planned to enter operation by 2035.
In March 2026, TerraPower Isotopes announced plans to build a $450 million, 250,000-square-foot facility in Philadelphia for the production of actinium-225, a radioactive isotope used in radiation treatments for diseases such as leukemia and melanoma. The project will receive a $7 million grant through the Pennsylvania Strategic Investments to Enhance Sites program and a $3 million Pennsylvania First grant.
From Wikipedia’s article on TerraPower, shared under CC BY-SA 4.0.4