Another non-light reactor has reached criticality under the Department of Energy’s reactor pilot program, as California-based Valar Atomics achieved the milestone on June 18.
Valar Atomics conducted its zero-power criticality testing at Utah San Rafael Energy Lab in Emery County, Utah, marking the first reactor to hit this feat outside of a national laboratory, according to DOE’s press release. The company joins Antares Nuclear in reaching this criticality milestone.
The company’s Ward 250 reactor is a helium-cooled, tristructural isotropic – or TRISO-fueled, high-temperature gas microreactor that when commercial would generate five megawatts of electricity. DOE approved Valar Atomics preliminary design safety analysis in February and its documented safety analysis in late April.
At the annual meeting of the Energy Facility Contractors Group (EFCOG) in Washington, D.C. on June 17, DOEs Office of Nuclear Energy’s Acting Chief Operating Officer, Lauren Joyce, said that the second reactor hitting criticality was imminent
“Nine months ago, this was an empty site,” CEO of Valar Atomics Isaiah Taylor said in the press release. “Today, there’s a critical reactor on it, built and operated by the Valar team, We met the milestone the executive order set. This reactor was built to make power, and that’s exactly where we’re headed. I’m grateful to the Department of Energy, the State of Utah, the local community, and the many people who got us here.”
In February, Secretary of Energy Chris Wright visited Utah when Valar Atomics’ Ward 250 test reactor was being transported from March Air Force Base (AFB), Calif. to Hill AFB, Utah. During that visit, Wright said that he believed that three reactors would hit criticality, upping his prediction he previously made of one to two reactors in November 2025.
“Today marks another historic moment for America’s nuclear renaissance,” Wright said. “From the first-ever airlift of a small reactor aboard a U.S. military C-17 to successful zero-power criticality testing, Valar Atomics is delivering achievements that mark a revolutionary moment for advanced nuclear in this country.”