politics
Three of Four Reactor Startups Reach Criticality Near July 4 Target
Valar Atomics, Antares Energy and Deployable Energy each reached criticality in tests at national laboratories. The milestones satisfied a May 2025 executive order from President Trump directing the Department of Energy to launch a reactor pilot program. A fourth startup, Aalo Atomics, remains close to the same target.
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President Donald Trump’s May 2025 executive order directed the Department of Energy to launch the Reactor Pilot Program with the goal of having at least three reactor startups achieve criticality by July 4, 2026. Forbes reported that three companies have now met that target. Valar Atomics, based in El Segundo, California, achieved criticality twice.
The first test occurred at Los Alamos National Laboratory with only the reactor core. The second took place in June 2026 at the San Rafael Energy Lab in Utah with its Ward250 reactor. In February 2026 the U.S.
Air Force transported Valar Atomics equipment from southern California to Utah in three C-17 cargo planes. One month later the company raised $450 million at a $2 billion valuation. On July 1, 2026, Valar Atomics announced a deal to build a 30-megawatt nuclear-powered data center with Nvidia in Utah.
Antares Energy, based in Torrance, California, achieved criticality in early June 2026 at Idaho National Laboratory with its Mark-0 reactor. It became the 53rd reactor to reach criticality there and the first privately funded non-light-water reactor to do so in four decades.
The company has tested its microreactor at NASA’s Marshall Space Flight Center in Huntsville, Alabama, targeting 100 kilowatts of power for a future moon base.
Antares Energy has an order to deliver reactors to Joint Base San Antonio in 2027. Founded one year earlier by Bobby Gallagher, a former Australian Army member who built offshore oil rigs, the company partnered with Texas A&M’s nuclear engineering department to develop its 1-megawatt Unity Nuclear Battery shipping-container reactor.
