Valar Atomics, based in El Segundo, California, has achieved cold or zero-power criticality—a state in which a reactor sustains a nuclear chain reaction but does not yet generate usable power, tells Wired.com. The reactor used was not fully the company’s own design; rather, it combined Valar’s fuel and technology with structural components from Los Alamos National Laboratory. This achievement places Valar as the first company in the U.S. Department of Energy (DOE) pilot program to reach this milestone ahead of a goal date of July 4, 2026.
Cold criticality confirms that the reactor’s physics and design are viable; it proves the chain reaction can be sustained, but it falls short of producing heat or electricity. Valar secured roughly $130 million in new funding with backing from investors such as Palmer Luckey and Shyam Sankar and has set a target to launch a fully operational reactor by July 4, 2026.
A major factor in this accelerated timeline is the DOE pilot program, which emerged from an executive order signed in May under the Nuclear Regulatory Commission-regulation reform agenda, allowing startups to bypass certain regulatory hurdles to test early prototypes. However, Valar (and others) still must seek full NRC licensing for commercial deployment.
The development reflects a broader shift in nuclear innovation: smaller reactors, faster development cycles, and deeper private-sector involvement. Yet it remains just a launch point: commercial viability, regulatory review, and long-term safety all remain on the path ahead.