US Says Antares’ Small Nuclear Reactor Reaches ‘Criticality’
(Bloomberg) -- The Trump administration announced a small modular nuclear reactor reached a critical milestone Thursday.
The small reactor being developed by Antares Nuclear Inc. participating in an Energy Department pilot program reached “criticality,” the agency said in a statement. The milestone occurs when a nuclear chain reaction becomes self-sustaining enough to produce a steady release of energy.
The achievement shows that the Trump administration’s effort to remove regulatory barriers is helping demonstrate the viability of new nuclear technologies.
The White House is pushing for wider deployment of both large, conventional reactors and smaller ones from companies like Antares. While the Antares system is still far from being used in a commercial capacity, achieving criticality is a notable step toward that goal. The company, which is initially targeting military applications, said it expects to see its systems deployed in the field by the end of 2028.
“This initial criticality is the first step on a roadmap toward producing electricity,” Jordan Bramble, Antares’ chief executive officer, said during a video briefing Friday.
The Energy Department has set a goal of achieving the milestone in at least three test reactors by July 4 and selected projects from Antares, Oklo Inc., Aalo Atomics Inc., Atomic Alchemy Inc., Deep Fission Inc., Last Energy Inc., Natura Resources LLC, Radiant Energy Inc., Terrestrial Energy Inc., and Valar Atomics Inc. to participate in a program designed to expedite development and authorization of reactors.
(Updates with comment from CEO in penultimate paragraph.)
©2026 Bloomberg L.P.
