Big Tech is hoping small modular reactors can help meet the energy demands from data centers—but the tech is far from proven.
BY Adele Peters5 minute read As tech companies scramble to find new power sources for AI's huge energy needs, some of them are turning to startups developing new nuclear technology. Google recently announced that it plans to begin using power from Kairos Power's small modular reactors by 2030. Amazon is investing in another nuclear startup, X-Energy. Microsoft hasn't yet announced a similar investment, though it posted a job listing last year that included looking at "optimal integration" of next-generation nuclear reactors. The newest nuclear tech claims to be safer and more sustainable than traditional nuclear power plants. But some critics argue that "advanced" nuclear technology isn't necessarily that advanced—and that it's unlikely to be ready on the timeline that Big Tech wants. "I think it's highly unlikely that these reactors are going to perform the way that their developers are promising," says Ed Lyman, director of the nuclear power safety program at the nonprofit Union of Concerned Scientists. X-Energy makes a small reactor filled with fuel "pebbles"—each around the size of a billiard ball—that contain thousands of tiny particles of uranium that are each surrounded by layers of carbon. (The type of fuel is called TRISO, or "tristructural isotropic" fuel; the Department of Energy calls it "the most robust nuclear fuel on Earth," a claim Lyman says is "wildly overhyped.") The fuel continuously rotates through the core, along with helium that absorbs the heat; the heat turns water into steam to make electricity. The company calls its design "meltdown-proof" and says the particles "retain their integrity under all foreseeable conditions." Subscribe to the Compass Newsletter. Fast Company's trending stories delivered to you daily Privacy Policy | Fast Company Newsletters Lyman, who wrote a detailed report about next-gen nuclear reactors in 2021 and closely follows the industry, argues that it's too early to say that it's safe. "X-Energy's specific fuel…