The U.S. Department of Energy on June 18 said that DOE Reactor Pilot Program participant Valar Atomics’ advanced reactor design, Ward 250, successfully completed a zero-power fueled criticality demonstration.
The experiment took place at the Utah San Rafael Energy Lab in Emery County, Utah, and marks the first DOE authorized reactor built outside of a national laboratory.
Ward 250 is the second of multiple advanced reactors anticipated to go critical by the July 4th deadline set by President Trump in his May 2025 executive order. Criticality demonstrates that Ward 250 can sustain a controlled nuclear chain reaction, which must be achieved before the reactor can generate power.
Earlier this month, Antares Nuclear’s Mark-0 reactor achieved criticality at Idaho National Laboratory.
The Department’s Reactor Pilot Program has catalyzed rapid innovation and progress in furthering American advanced reactor designs, DOE said.
The Reactor Pilot Program leverages DOE authorization to expeditiously certify and construct first-of-a-kind advanced reactor designs for demonstration.
Building on the Reactor Pilot Program’s success, DOE recently established the Nuclear Energy Launch Pad to further accelerate the deployment of advanced nuclear technologies.