Valar Atomics Brings 100-Kilowatt Ward 250 Critical Outside National Labs for First Time
Updated
Updated · autonocion.com · Jun 30
Valar Atomics Brings 100-Kilowatt Ward 250 Critical Outside National Labs for First Time
3 articles · Updated · autonocion.com · Jun 30
Summary
June 18 marked the first DOE-authorized reactor criticality outside a U.S. national laboratory, as Valar Atomics switched on its 100-kilowatt thermal Ward 250 microreactor at Utah’s San Rafael Energy Lab near Orangeville.
The milestone was enabled by a DOE approval pathway created under a May 2025 Trump executive order that sought at least three advanced test reactors critical by July 4, 2026; Valar became the second project to qualify.
Ward 250 is a helium-cooled, graphite-core microreactor about the size of a minivan using TRISO fuel with high-assay low-enriched uranium; DOE described the event as a zero-power fueled criticality demonstration, meaning a self-sustaining chain reaction without meaningful heat output.
By June 22, the reactor had climbed to 10 kilowatts as engineers began staged power ascension toward its 100-kilowatt test rating, while Valar targets a future 5-megawatt electric commercial version for industrial sites and data centers.
The Utah site in coal-heavy Emery County underscores the broader policy aim: proving advanced nuclear on nonfederal ground where existing energy infrastructure already sits, rather than inside the traditional national-lab system.
Valar Atomics' Ward 250 microreactor achieved zero-power criticality at the Utah San Rafael Energy Lab, marking a major step in advanced nuclear energy. This means the reactor’s fission chain reaction became self-sustaining, proving its core physics in a fully integrated system ready for power operations. As the first Department of Energy-authorized reactor built outside a national lab, Ward 250 highlights a shift toward broader industry involvement. This achievement directly supports the DOE’s Reactor Pilot Program goals, showing progress in deploying innovative nuclear technology and setting the stage for further milestones and wider adoption.