When Meta announced last week that it’s looking for a nuclear energy developer to power its future AI operations, it joined a growing cadre of tech companies all suddenly repeating the same refrain: We need more power—preferably carbon-free—and lots of it.
Electricity demand in the United States is expected to grow more than 15 percent over the next five years after remaining flat for the last two decades, according to a recent report from power sector consulting firm Grid Strategies. Most of the growth will be driven by the needs of data centers and their operators, who are scrambling to secure large amounts of reliable power while keeping their carbon neutral goals.
Nuclear energy fits that bill, and over the last few months, Amazon, Google, and Microsoft have all announced ambitious deals to acquire it for their operations. Some of the plans aim to secure energy in the near term from existing power plants. Others focus on the long game and include investments in next-generation nuclear energy and small modular reactors (SMRs) that don’t yet exist on a commercial scale.
“Data centers have grown in size and AI is dramatically changing the future [energy] forecast,” says Dan Stout, founder of Advanced Nuclear Advisors in Chattanooga, Tenn. “In the 2030s, the grid will have less coal and there will be some constraints on gas. So nuclear energy’s power density and carbon-free high reliability is attractive, and tech companies are starting to take action on new nuclear deployments,” he says.
Big Tech Turns Its Attention to Nuclear Power
Amazon kicked off the bevy of public announcements in March when it bought a data center adjacent to a nuclear power plant in Pennsylvania. The purchase came with 300 megawatts of behind-the-meter electricity. After closing the deal, Amazon requested another 180 MW. The request caused a dustup over energy fairness, and in November regulators rejected it, leaving Amazon looking for other options. Tech companies are watching the precedent-setting situation closely.
Meanwhile, Microsoft was inking an agreement with Constellation Energy to restart a shuttered nuclear reactor on Three Mile Island—the site of the worst nuclear disaster in U.S. history. The plan, announced in September, calls for the reactor to supply 835 MW to grid operator PJM, and for Microsoft to buy enough of that power to match the electricity consumed by its data centers in the PJM Interconnection.
Then in October, just two days apart, Google and Amazon both announced investments in startups developing SMRs. The smaller size and modular design of SMRs could make building them faster, cheaper and more predictable than conventional nuclear reactors. They also come with enhanced safety features, and could be built closer to transmission lines.
SMRs are still at least five years from commercial operation in the United States. A year ago the first planned SMR in the United States was cancelled due to rising costs and a lack of customers. (China is building an SMR called the Linglong One on the island of Hainan, which is scheduled to be operational in 2026.)
To move things along, Amazon led a US $500 million financing round to support X-energy in Rockville, Md., which is developing a gas-cooled SMR. The financing will help X-energy finish its reactor design and build a nuclear fuel fabrication facility. The plan is to build multiple SMRs producing at least 5 GW total by 2039. Each reactor will provide 80 MW of electricity.
Google, for its part, is backing Kairos Power with a 500 MW development agreement. The Alameda, Calif.-based company is developing a molten fluoride salt-cooled SMR and has received construction permits from the U.S. Nuclear Regulatory Commission to build two demonstration facilities, both in Oak Ridge, Tenn. The company says the facilities will be operational by 2030.
TRISO Fuel Promises to Shrink Reactors
The reactors that both Kairos and X-energy are developing run on tri-structural isotropic (TRISO) particle fuel. It’s made of uranium, carbon, and oxygen encapsulated in graphite kernels the size of a poppy seed. The kernels get loaded into golf ball-size spheres called pebbles that are also made of graphite. Each pebble contains thousands of fuel kernels.
The structure of the pebble encapsulation enables the fuel to withstand very high temperatures, so even in worst-case accidents, the pebbles won’t melt. The coatings “essentially provide the key safety functions that the large containment concrete structure is providing for conventional reactor technologies,” says Mike Laufer, co-founder of Kairos.
If regulators approve, the built-in containment feature could shrink the footprint of nuclear plants by reducing the size of containment structures. The U.S. Department of Energy has been developing and extensively testing TRISO fuel over the last two decades.
Kairos will use TRISO fuel in its high-temperature, low-pressure, fluoride salt-cooled reactor. In this design, fuel pebbles in the reactor core undergo fission, generating heat that transfers to the surrounding molten salt. Heat exchangers transfer the heat to boil water and generate steam,which drives a turbine and generates electricity. The molten salt acts as an additional safety barrier, chemically absorbing any fission products that escape the pebbles, Laufer says. Kairos’ commercial reactors will each generate about 75 MW of electricity, Laufer says.
X-energy plans to use TRISO fuel is its high-temperature gas-cooled reactor. In this design, helium gas runs through the reactor core. As the fuel pebbles undergo fission, the gas extracts the heat, which is used to boil water and generates steam to drive a turbine. Each fuel pebble will constantly shuffle through the reactor, passing through about six times. “The reactor is a lot like a gumball machine,” says Benjamin Reinke, vice president of global business development at X-energy. A mechanical corkscrew drives a pebble in an auger out of the system., and the pebble is checked to see if it’s fully burned up. If not, it goes back to into the top of the reactor, he says.
X-energy is working on getting a license to produce TRISO fuel on a commercial scale at a facility it plans to build in Oak Ridge. The company’s first customer, a Dow petrochemical plant in Seadrift, Tex., plans to replace its gas boilers with X-energy’s SMRs, which will create steam and electricity for the plant and possibly for the grid. X-energy’s deal with Amazon also supports a four-unit, 320-MW project with regional utility Energy Northwest in Richland, Wash.
Tech companies for the last decade have been investing in wind and solar energy too, but the power from these sources is intermittent, and may not be enough to meet the needs of power-guzzling AI.
The arrangements between big tech and small nuclear signal the beginning of a trend, says Stout. Meta’s announcement last week that it’s putting out a request for proposals for up to 4 gigawatts of nuclear power may be the most recent addition to that trend, but it’s probably not the last. Says Stout: “I expect there’s going to be more.”
This article was updated on 10 December 2024 to clarify the agreement between Google and Kairos Power.
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