The nuclear industry is racing to launch advanced small reactors by the early 2030s, aiming to meet the deep-pocketed technology sector’s growing need for electricity to fuel artificial intelligence.

The world has relied largely on the same pressurized-water reactor technology for the past 70 years, but those plants have proven incredibly expensive to build in the U.S. in the 21st century.

The first new nuclear plant completed in decades, reactors 3 and 4 at Plant Vogtle in Georgia, infamously cost about $18 billion more than expected and opened seven years behind schedule. Each of those reactors can generate 1,114 megawatts of electricity, enough for more than 800,000 homes.

“Doing these new builds with that older, high pressure technology is just unaffordable,” Chris Levesque, CEO of TerraPower, an advanced reactor company co-founded and backed by Bill Gates, told CNBC.

Despite growing interest in restarting closed reactors, such as Palisades in Michigan and Three Mile Island in Pennsylvania, as a quicker and cheaper near-term solution, there remains “a whole lot of hesitation about a brand new plant,” Levesque said.

The advanced reactors under development promise to have smaller, lighter footprints that could make them cheaper and quicker to build when they are fully commercialized. But the industry is crowded with more than 90 different technologies in various stages of development around the world, according to the Nuclear Energy Agency.

The utility and tech sectors need to winnow down the field to five or 10 companies with the right technology, said John Ketchum, CEO of NextEra Energy, the largest power company by market capitalization in the U.S.

“A lot of them are under capitalized,” Ketchum said of the small nuclear startups designing advanced reactors. “So we’ve got to pick out the ones that we really want to get behind and make the bets,” the CEO said at the CERAWeek energy conference in Houston earlier this month.

Ketchum sees the first advanced reactor coming online around 2031 in the U.S., with more units potentially on the way around 2035. Technology companies will serve as a catalyst, with Levesque saying they are a “huge force” that can drive the industry forward due to their immense demand for electricity coupled with their deep pockets. Alphabet, Amazon, Meta and Microsoft together are worth seven times the value of the entire S&P 500 utility sector.

The following are some of the leading players in the U.S. market to revive nuclear power, all three of them private but with significant financial backing — often from tech companies — and customers already lined up.

TerraPower

TerraPower is the first advanced reactor company in the U.S. to move from design to construction, breaking ground on its first plant near a former coal site in Kemmerer, Wyoming in the summer of 2024. The company aims to start dispatching power by the end of 2030 to Warren Buffett’s PacifiCorp.

TerraPower’s Natrium reactor operates at atmospheric temperature, a feature that Levesque says will reduce construction costs.

The U.S. currently relies on reactors that operate at about 300 Celsius (572 degrees Fahrenheit) and are cooled by water. The system operates under high pressure — water boils at 100 degree Celsius — to keep the coolant liquid, and the plants need heavy, expensive components to contain the pressure, Levesque said.

TerraPower uses sodium, rather than water, as a coolant. Liquid sodium boils at 900 Celsius, much higher than the Natrium reactor’s operating temperature of around 500 Celsius. That means the plant does not need to be pressurized, Levesque said.

Using a low-pressure, lighter plant to avoid high pressure systems “reduces tons of steel, tons of concrete, labor hours, numbers of systems,” Levesque said. He estimates that Natrium plants will cost about half as much to build as a traditional nuclear plant, with prices coming down as more are built.

The Natrium reactor has a power capacity of 345 megawatts, enough for more than 250,000 homes. A plant will have the ability to ramp up to 500 megawatts for several hours by storing heat in a thermal battery made of molten salt, Levesque says. The idea is to be able to dispatch power on demand to the grid when renewable solar and wind power fade because the sun isn’t shinning or winds are slack.

TerraPower has the financial backing of its key founder Bill Gates, SK Group, one of South Korea’s largest energy providers, and ArcelorMittal, a steelmaker. Gates and SK Group led TerraPower’s $830 million funding round in 2022. The Wyoming project is backed by $2 billion from the Department of Energy, which TerraPower says it will match dollar for dollar.

TerraPower filed its construction license application with the Nuclear Regulatory Commission in 2024 and expects the regulator will issue a permit in December 2026.

“We’re trying to show folks we’re inevitable,” Levesque said.

X-Energy

Of all the advanced reactor companies, X-Energy is the first to win a direct investment from a tech company, securing hundreds of millions of dollars from Amazon to build its Xe-100 reactor.

“What this sector needs is risk capital to invest in plants because U.S. utilities aren’t doing it today,” X-Energy CEO Clay Sell told CNBC.

X-Energy’s most recent financing round raised $700 million, led by Amazon and with additional capital from Citadel founder Ken Griffin, Ares Management, Segra Capital Management, Jane Street Capital and the University of Michigan, among others.

“One of the largest corporations in America, a company that is in size larger than the entirety of the investor-owned utility sector in the U.S., was stepping forward and saying we want to facilitate the new nuclear future in the United States,” Sell said of Amazon’s investment.

The cash will largely go to completing the reactor design so it’s ready for construction, and finishing the first phase of X-Energy’s fuel facility, Sell said.

The Xe-100 is an 80 megawatt reactor sold in a pack of four units to construct 320 megawatts in total, the CEO said. The multiple units create redundancy and the small size allows the biggest component, the reactor vessel, to ship from a factory via road to the construction site, Sell said.

The reactor uses helium gas as a coolant rather than water. X-Energy has its own proprietary fuel made of graphite pebbles that contain uranium kernels encased in ceramic. Sell said the graphite can’t melt, which makes the plant “intrinsically safe.”

Amazon’s investment will finance four Xe-100 reactors in Washington state that will be built, owned and operated by Energy Northwest, a utility, with plants coming online in the early 2030s. The intent is to scale up to a dozen Xe-100s in Washington, Sell said.

X-Energy is also working with Dow Inc. to deploy four reactors at the chemical company’s manufacturing facility in Seadrift, Texas. The Department of Energy has awarded X-Energy up to $1.2 billion to develop and deploy its technoloy.

X-Energy aims to become the first company to commission an operational advanced reactor in the U.S., Sell said.

Kairos Power

Kairos Power signed a contract with Alphabet’s Google unit last year to deploy multiple, advanced reactors, aiming to supply the YouTube company with 500 megawatts of power. The first reactor is expected to come online in 2030, with additional deployments through 2035.

Financial terms of the deal weren’t disclosed, but the Google contract is “immensely important,” allowing Kairos to “plan the infrastructure not just for one project but for a series of projects,” CEO Mike Laufer told CNBC.

“It allows us to scale our infrastructure, production — our manufacturing capabilities,” Laufer said.

The 75-megawatt Kairos’ reactor will be deployed in pairs to provide 150 megawatts of total power. Similar to TerraPower, Kairos’ reactor operates at near atmospheric pressure using molten fluoride salt instead of water as coolant. Like X-Energy, Kairos uses fuel that encases uranium kernels in ceramic and graphite pebbles that can’t melt in high-temperature reactors, according to the company.

Kairos is building a low-power, demonstration reactor in Oak Ridge, Tennessee to showcase its ability “to deliver clean, safe, and affordable nuclear heat.” Oak Ridge, site of a national laboratory about 25 miles west of Knoxville, was where uranium was enriched as part of the Manhattan Project to build the first atomic bombs.

Today, there will be a “natural thinning” in the number of advance reactor companies, Kairos CEO Laufer said: “It’s going to be driven by who can actually be in a position to execute projects,” he said.