DOE Confirms Fourth Advanced Reactor Reaches Criticality Milestone
Four advanced nuclear reactor designs have now achieved “criticality” under a federally backed testing campaign, exceeding a White House target set for the July 4 anniversary, Rigzone reports.
Austin, Texas-based Aalo Atomics announced its Critical Test Reactor sustained a chain reaction at Idaho National Laboratory, going from groundbreaking to criticality in less than eight months. The Department of Energy confirmed it as the fourth DOE-authorized advanced reactor to hit the milestone, following Antares Nuclear’s Mark-0 reactor, Valar Atomics’ Ward 250, and Deployable Energy’s Unity.
Market Impact
The milestone stems from President Trump’s May 2025 executive order, which set a goal of at least three advanced reactors achieving criticality by July 4, 2026, as part of a broader push to grow US nuclear capacity from roughly 100 gigawatts to 400 gigawatts by 2050. The order also launched DOE’s Reactor Pilot Program, which selected 11 reactor designs in August 2025 for expedited testing outside the traditional national lab process, with streamlined environmental reviews.
Aalo Atomics said its reactor demonstrates the core technology for its planned 10 MWe units, which will be bundled into 50 MWe “Aalo Pods” designed specifically to power AI data centers. The company said it has already started work on a second reactor at its Aalo-X Campus at Idaho National Laboratory, targeting 2027 to power an on-site data center, and is building a one-million-square-foot factory to mass-produce reactor units on an assembly line.
What It Means for Subcontractors
- Reactor siting is shifting toward campus-style buildouts like Aalo-X at Idaho National Laboratory, where a second commercial reactor and on-site data center are already planned for 2027, meaning civil, electrical, and mechanical subs should track INL-area procurement as a template for future sites.
- The move to “assembly-line” reactor manufacturing in a one-million-square-foot factory signals coming demand for modular fabrication trades, including structural steel, piping, and quality-control inspection roles tied to serial production rather than one-off builds.
- Electrical and E&I subcontractors serving data centers should note that Aalo Pods are purpose-built to co-locate 50 MWe generation with AI data centers, pointing to future bid packages combining reactor interconnection work with data-center power distribution on the same site.
- With three other companies (Antares Nuclear, Valar Atomics, Deployable Energy) also clearing criticality, subcontractors in Idaho and other DOE pilot-program states should identify which of the 11 selected designs are advancing toward construction permits, since site prep and foundation work typically follows within months of a criticality demonstration.
- DOE’s streamlined environmental review process under the Reactor Pilot Program could compress the timeline between design approval and groundbreaking, so field service firms should get pre-qualified with reactor developers now rather than waiting for formal EPC awards.
