The first commercial nuclear-power projects in a decade are now under construction in the U.S., a potential turning point for a segment of the power industry that has been stuck in neutral for years.
A project by TerraPower, a company founded by Bill Gates almost 20 years ago, started construction Wednesday in Wyoming, while Kairos Power broke ground last week in Tennessee on a plant that intends to sell power to Google.
For years, nuclear power’s would-be revival has been more concept than reality, dominated by designs and climate pledges, but with little under construction. The renewed interest comes alongside the biggest jump in electricity demand in a generation, much of it driven by the need to power data centers for artificial intelligence. That has sent the tech industry on the hunt for towering amounts of energy.
TerraPower and Kairos are among the developers trying to prove that smaller streamlined reactor designs can overcome the problems the industry is known for: cost overruns and delays that contributed to a loss of enthusiasm for the technology. Most of the nuclear power plants in U.S. were built before 1990.
“This isn’t a test reactor,” said Chris Levesque, president and chief executive of TerraPower. “This is a grid-scale nuclear reactor that will be built in 42 months.”
Federal regulators last month gave TerraPower the greenlight for construction of a nuclear plant on a site where it had been building nonnuclear support facilities for nearly two years. It was the first such license in years for a commercial project, though the company will need a separate approval to load fuel and begin operations.
Getting to this point required the work of 1,000 engineers, Levesque said. “It’s going to take a lot more persistence going forward,” he said. “It’s really not a business for the faint at heart.”
The project will employ up to 1,600 construction workers. Once operating, it expects to have about 250 employees.
Traditional U.S. reactors use water to cool the reactor core. TerraPower will use liquid sodium, which has a higher boiling point and allows operations at lower pressures with a more streamlined design than conventional projects. The 345-megawatt plant will include an energy-storage system that could boost output to 500 megawatts during times of peak electricity demand.
The TerraPower reactor will deliver electricity into utility PacifiCorp’s multistate transmission system. The reactor is part of a public-private partnership with the Energy Department’s Advanced Reactor Demonstration Program, a 50-50 cost share that has authorized up to $2 billion in federal funding for the project.
Earlier this year, Facebook parent Meta Platforms said it would provide capital to accelerate the development of up to eight additional TerraPower units. Locations haven’t yet been announced.
Gates is still a major investor in TerraPower, which is privately held. NVentures, the venture capital arm of Nvidia, and shipbuilder HD Hyundai are among other big backers.
In Oak Ridge, Tenn., the first Kairos plant will supply up to 50 megawatts of electricity to the Tennessee Valley Authority, a federal utility. The Kairos reactor is licensed for research and development but is still allowed to produce and sell electricity.
Supplying power to TVA will help to offset the carbon emissions of Google data centers in Tennessee and Alabama. The tech company agreed in 2024 to buy power generated by several Kairos reactors and hopes to receive up to 500 gigawatts of nuclear power over the next 10 years.
Kairos uses molten fluoride salt as a coolant, allowing it to operate at low pressures and high temperatures, and it also has a smaller demonstration reactor under construction in Oak Ridge.
The adjacent locations allow the same contractors and crews to move from one site to the next. Kairos has tried to mirror the rapid prototyping of the aerospace industry by building engineering test units at a factory in New Mexico.
“Virtually nothing” for the latest project will be first of a kind, said Mike Laufer, CEO of Kairos. “We understood the iterative process was going to be really valuable for the reactor system and for hardware and those components. We did not anticipate how powerful it could be on the civil construction side.”
About 20% of U.S. power comes from nuclear plants. The two most recent commercial reactors built in the U.S. were larger-scale projects that began construction in Georgia in 2013. One was finished in 2023 and the other in 2024, with total project costs that rose well over $30 billion.
Smaller-scale reactors are considered less of a risk than large projects, but still must prove themselves commercially.
“In more than a decade we have not broken ground on a new commercial nuclear project and now we have two under way,” said Adam Stein, director for nuclear energy innovation at the Breakthrough Institute, a think tank that advocates for expanding nuclear power..
“It’s very significant,” he added. “These are both long planned projects that didn’t just materialize in the last year or two.”
Write to Jennifer Hiller at jennifer.hiller@wsj.com
