U.S. Hits 3 Advanced Reactor Criticality Goal by July 4 as Commercial Hurdles Loom
Updated
Updated · POLITICO · Jul 1
U.S. Hits 3 Advanced Reactor Criticality Goal by July 4 as Commercial Hurdles Loom
3 articles · Updated · POLITICO · Jul 1
Summary
Deployable Energy’s reactor became the third U.S. advanced reactor to reach criticality under Trump, allowing the Energy Department to meet its self-imposed July 4 target.
DOE says the milestone reflects a push to speed smaller-reactor development as data centers drive power demand, after Antares and Valar Atomics hit criticality in June and Aalo could follow before July 4.
Commercial use still remains distant: no U.S. microreactors or SMRs are operating on the grid, and Nuclear Regulatory Commission licenses are still required even as DOE seeks faster reviews.
Key obstacles extend beyond criticality, including scarce HALEU fuel, financing for multibillion-dollar projects, and the challenge of scaling demonstration units into reactors large enough for data-center or grid deployment.
The administration wants to quadruple U.S. net nuclear capacity to 400 gigawatts by 2050, but analysts say these demonstrations are a technical step forward rather than a near-term commercial breakthrough.
Can small nuclear reactors power the AI boom despite critical fuel shortages and massive funding gaps?
With demonstration reactors now online, what is the true timeline for them to power our data centers and cities?
Can America rebuild its entire nuclear supply chain fast enough to meet its ambitious 2050 energy goals?
Quadrupling U.S. Nuclear Capacity by 2050: Breakthroughs, Policy, and the Race for Advanced Reactor Deployment
Overview
In June 2026, the U.S. advanced nuclear sector reached a major milestone as Antares Nuclear’s Mark-0 microreactor and Valar Atomics’ Ward 250 both achieved criticality, marking rapid progress in next-generation reactor development. These successes were made possible by decades of Department of Energy investment in advanced fuel technology and strong support from Idaho National Laboratory. Valar Atomics’ achievement was further enabled by executive orders that provided a clear mandate and streamlined federal review, including oversight by DOE officials and a joint test group. Together, these breakthroughs highlight the power of coordinated policy, technical innovation, and public-private collaboration in advancing clean energy.