Valar Atomics Says It's the First Nuclear Startup to Achieve Criticality

Valar Atomics, a nuclear startup based in El Segundo, California, announced it has achieved criticality—a key milestone in nuclear reactor development—making it the first startup in a Department of Energy (DOE) pilot program to do so. This pilot program, initiated following a 2020 executive order, aims to help at least three startups reach criticality by July 4, 2024, and has accelerated regulatory processes that traditionally slowed nuclear innovation. Valar’s achievement involved a reactor combining its proprietary fuel and technology with structural components from Los Alamos National Laboratory, marking a significant step in validating its reactor design and fuel geometry through zero-power or cold criticality tests. Criticality refers to the point at which a nuclear reactor sustains a chain reaction, essential for power generation, though cold criticality itself does not produce usable heat. Valar’s milestone demonstrates the physics of its reactor concept, though it is not yet producing power. The startup, which emerged from stealth earlier this year and recently