Nuclear Reactor Race Heats Up to Power America's AI Data Centers
- Jul 20
- 3 min read
WHAT HAPPENED: A race started by President Trump is producing the fastest construction of new nuclear reactors America has seen in generations. Under a challenge to build experimental reactors by July 4, 2026 — the 250th anniversary of the Declaration of Independence — a cluster of startups has now switched on small test reactors that, if the technology scales, could power the data centers driving the artificial intelligence boom. The push is drawing fresh national attention this week as the reactors move from milestone to operation.
At least four companies hit the criticality milestone — the point where a nuclear chain reaction becomes self-sustaining — around the July 4 deadline: Antares Nuclear, Valar Atomics, and Aalo Atomics inside the government's fast-track program, plus Deployable Energy outside it. In a striking first, a nuclear reactor has now been used to power an Nvidia AI chip, a symbolic fusion of the two technologies driving the entire effort.
WHAT WE KNOW: The vehicle for the sprint is the Department of Energy's Reactor Pilot Program, created after Trump's executive orders on nuclear energy. The program is designed to help companies build and run test reactors quickly — in large part by radically cutting back the regulatory requirements that have historically made new reactors a decade-long, multibillion-dollar proposition.
The results have been fast by any standard. Antares announced its reactor went critical on June 4. Valar Atomics followed on June 18 and says it is now producing tens of kilowatts of heat from a reactor core operating out of a tentlike structure in the Utah desert. Aalo Atomics reached criticality by the July 4 deadline at its test site. These are small experimental units, not power plants — but they are real fission reactors, built in months rather than decades.
The commercial logic is explicit: artificial intelligence. Data centers training and running AI models are projected to consume electricity on a scale the existing grid cannot supply, and tech companies want firm, around-the-clock, carbon-free power. Small reactors sited next to data centers are the industry's proposed answer, and the startups' pitch to investors leans heavily on that demand.
BACKGROUND: America's nuclear industry has spent decades defined by stagnation — the two most recent large reactors, at Georgia's Plant Vogtle, arrived years late and billions over budget. The new approach inverts the model: instead of gigawatt-scale plants licensed over a decade by the Nuclear Regulatory Commission, the pilot program authorizes small test reactors on Department of Energy sites under a compressed review, betting that iteration and mass production can do for reactors what SpaceX did for rockets.
Trump's executive orders set the direction: quadruple US nuclear capacity, fast-track approvals, and treat energy abundance as a national-security race with China, which is building reactors at a pace the West has not matched. The July 4 deadline was a political flourish, but it worked as an organizing device — companies publicly raced each other to criticality through June.
REACTION: The nuclear industry and its investors have celebrated the milestones as proof that American reactors can be built quickly again. But critics — including veteran nuclear engineers and safety advocates — warn that the breakneck pace is compromising safety and public trust. Slashing regulations, they argue, undoes decades of hard-won safety lessons, and a single serious accident at a fast-tracked reactor could set the entire industry back a generation, just as Three Mile Island did in 1979.
There is also skepticism on the commercial side. Tens of kilowatts of heat from a test core is many orders of magnitude short of the hundreds of megawatts a large AI data-center campus demands. The gap between a criticality demonstration in a desert tent and a licensed, grid-connected power plant remains enormous — technically, financially, and politically.
WHAT TO WATCH: The next phase is scale. Watch whether the startups can move from test reactors to power-producing units, whether the NRC's parallel licensing reforms hold up in court, and whether utilities and hyperscalers — Microsoft, Google, Amazon, Meta — sign firm power-purchase agreements with the new players rather than just announcing exploratory partnerships. Also watch the backlash: communities near proposed sites are already organizing over safety, water use, and grid costs.
The AI demand curve is the other variable. If data-center electricity consumption keeps compounding, the case for nuclear grows regardless of politics. If the AI buildout cools, the startups could find themselves with reactors seeking customers rather than customers seeking reactors.
BOTTOM LINE: America is building experimental nuclear reactors faster than at any point in living memory, driven by an AI power crunch and a president's deadline. Whether this becomes the start of a genuine atomic revival or a cautionary tale about speed over safety depends on what happens when these desert test units try to become real power plants.
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