NRC approves first non-light-water reactor permit in 40 years for Gates-backed Wyoming plant

The U.S. Nuclear Regulatory Commission on Wednesday issued its first construction permit for a commercial non-light-water reactor in more than 40 years, authorizing TerraPower to build a sodium-cooled nuclear plant near Kemmerer, Wyoming.

The permit is also the NRC’s first commercial nuclear construction permit of any kind in eight years, the commission said. TerraPower said construction on the reactor is set to begin within weeks, with completion of the up to $4 billion plant targeted for 2030.

The approval advances nuclear energy’s most prominent bid to supply power to AI data centers, while leaving unresolved the national problem of where to store spent nuclear fuel.

The reactor and the site

TerraPower’s 345-megawatt plant would use molten sodium, not water, to cool the reactor — a design that virtually all of the world’s commercial nuclear reactors do not use. The company said the plant is expected to produce up to 500 megawatts at peak, enough electricity for up to 400,000 homes.

The plant would be built near a coal-fired power plant being converted to burn natural gas outside Kemmerer, a town of about 2,500 people approximately 130 miles northeast of Salt Lake City. Site preparation work — not on the reactor itself — began in 2024.

“We have spent thousands of manpower hours working to achieve this momentous accomplishment,” TerraPower President and CEO Chris Levesque said in a statement.

A 40-year milestone in reactor licensing

The NRC said the permit is its first approval for a non-light-water commercial reactor in more than 40 years. The last such reactor to operate in the United States was the Fort St. Vrain nuclear plant in northern Colorado, a helium-cooled facility that produced electricity from the mid-1970s until its shutdown in 1989.

The commission’s last construction permit for a conventional light-water reactor went to Florida Power & Light Company in 2018 for a plant south of Miami. That project has yet to be built.

Gates and the data center connection

Microsoft co-founder Bill Gates is a founder of TerraPower and its primary investor. Gates has said nuclear power will be a “gigantic contributor” to powering data centers as electricity demand from AI computing surges.

“I wish I could deliver nuclear fission like three years earlier than I can, because then we’d have a perfect match to the current demand pattern of these data center guys,” Gates told reporters in October.

Gates said he has met with Energy Secretary Chris Wright and Interior Secretary Doug Burgum, and described the government as “very involved” in the TerraPower project.

Fuel supply and the waste backlog

TerraPower’s reactor requires a highly enriched form of uranium that in recent years has been obtainable only from Russia. The company said it is lining up domestic and South African sources to produce the fuel.

The federal government has yet to resolve the problem of thousands of tons of spent nuclear fuel that have accumulated at plants nationwide over decades. New Mexico and Texas have resisted becoming storage sites in the absence of a permanent federal solution.

In January, the U.S. Department of Energy announced what it called a first step toward possible partnerships with states to modernize the nuclear fuel cycle, including reprocessing spent fuel and disposing of waste. The agency gave states until April 1 to indicate interest in participating.

TerraPower said its reactor would produce relatively less nuclear waste than conventional reactors.