Three Advanced Reactors Hit Criticality Milestone Under Trump Executive Order, Accelerating U.S. Nuclear Renaissance

On July 1, 2026, the U.S. Department of Energy confirmed that Deployable Energy’s Unity microreactor achieved initial criticality at Idaho National Laboratory, marking the third privately developed reactor to reach this milestone in 2026 under DOE authorization. This follows Antares Nuclear’s Mark-0 sodium heat pipe reactor achieving zero-power criticality on June 4 at INL and Valar Atomics’ Ward 250 gas-cooled reactor reaching the same on or around June 18-22 at the Utah San Rafael Energy Lab. All align with the ambitious timeline set by Executive Order 14301, issued May 23, 2025, which directed DOE to reform reactor testing processes and aim for at least three test reactors achieving criticality by July 4, 2026, via the Reactor Pilot Program (RPP). Deployable Energy, operating under the subsequent Nuclear Energy Launch Pad initiative, was not among the original 11 RPP selectees but still met the goal through streamlined DOE pathways. Official DOE announcements and industry reports from World Nuclear News and the American Nuclear Society corroborate the sequence and technical details, highlighting zero-power fueled criticality demonstrations that validate core physics and safety without producing electricity. These milestones signal concrete progress in advanced nuclear deployment, bypassing traditional NRC licensing hurdles initially and positioning companies like Oklo, Radiant, and Aalo for further iteration. The developments underscore a policy-driven push toward domestic microreactor commercialization, with implications for energy independence through scalable, factory-built systems suited for remote, industrial, or grid-support applications.