Note: Single-source report; awaiting corroboration.
The U.S. Department of Energy (DOE) announced that Valar Atomics’ advanced reactor design, Ward 250, has completed a zero-power fueled criticality demonstration at the Utah San Rafael Energy Lab in Emery County, Utah. This marks the first DOE-authorized reactor built outside a national laboratory, according to the DOE.
U.S. Energy Secretary Chris Wright called the milestone significant for America’s nuclear industry, highlighting progress from the reactor's airlift to its successful criticality test. Achieving criticality confirms that Ward 250 can sustain a controlled nuclear chain reaction, a key requirement for power generation.
Ward 250 is the second advanced reactor expected to reach criticality by the July 4 deadline set by an executive order in May 2025. Earlier this month, the Mark-0 reactor developed by Antares Nuclear achieved criticality at Idaho National Laboratory.
Isaiah Taylor, Founder & CEO of Valar Atomics, noted the site was empty just nine months ago and now hosts a critical reactor built and operated by the Valar team. He thanked the DOE, the State of Utah, local communities, and others involved in the project.
The DOE’s Reactor Pilot Program aims to accelerate the certification and construction of advanced reactor designs. In addition to the program's progress, DOE recently launched the Nuclear Energy Launch Pad to further advance deployment of advanced nuclear technologies.