Catenaa, Wednesday, January 21, 2026-Valar Atomics has reached a key milestone in nuclear energy development by achieving zero-power criticality, or cold criticality, at its Nevada test site.
The self-sustaining uranium-235 reaction marks the “first heartbeat” of the startup’s high-temperature gas reactor (HTR) core.
Cold criticality means the reactor initiates fission without generating operational power, allowing scientists to study core physics and neutronic behavior safely.
The tests are part of Project NOVA, in collaboration with the Los Alamos National Laboratory’s National Criticality Experiments Research Center.
Valar Atomics’ HTR design uses helium and ceramic materials to stabilize reactions while collecting detailed data on reactivity control and burnable poisons.
The demonstration supports the US Department of Energy’s Nuclear Reactor Pilot Program, which aims to have several advanced reactors reach full operational criticality by July 2026.
Researchers emphasize that zero-power criticality is only the first step; scaling reactors to industrial size and harnessing power for the grid remain major technical hurdles.
Valar Atomics plans further experiments at higher temperatures and power levels, followed by DOE safety and regulatory evaluations.
Founder Isaiah Taylor described the milestone as proof of the reactor’s underlying physics and a foundation for future energy breakthroughs. Officials said progress in advanced nuclear reactors could help maintain grid stability, cut emissions, support industrial capacity, and strengthen US competitiveness in AI and technology.
