Idaho National Laboratory Opens DOME Microreactor Test Bed, Marking Major Milestone for Advanced Nuclear Energy in Idaho
IDAHO FALLS, Idaho — The Idaho National Laboratory has officially opened the world’s first nuclear microreactor test bed, a landmark development in the nation’s push to accelerate advanced nuclear energy and restore American leadership in the field. The National Reactor Innovation Center’s Demonstration of Microreactor Experiments — known as DOME — was formally launched on April 8, 2026, at INL’s Materials and Fuels Complex, located approximately 25 miles west of Idaho Falls on the Snake River Plain.
The opening drew officials from INL and the U.S. Department of Energy, who gathered at the sprawling desert facility to mark the occasion. The DOME test bed is now open to privately developed advanced reactors, giving the nuclear energy industry a first-of-its-kind, hands-on testing environment designed to enable rapid development, testing, and demonstration of next-generation reactor designs.
A World-First Facility Built for Industry
DOME was purpose-built to address the nation’s growing demand for advanced nuclear energy. According to officials, the facility was developed as a hands-on demonstration pathway for industry, recognizing that a dedicated, world-class testing environment of this nature could only be provided by a U.S. Department of Energy national laboratory. In a notable sign of urgency, construction of the test bed was accelerated by nearly a year to help industry meet the pressing national need for advanced nuclear energy.
“The DOME test bed will be a cornerstone of the Department of Energy’s comprehensive strategy to re-establish U.S. leadership in advanced nuclear technologies,” said Dr. Rian Bahran of the Department of Energy, according to remarks reported at the opening ceremony.
The DOME facility sits within INL’s Materials and Fuels Complex, formerly known as Argonne West. The complex serves as a broader testing center for advanced technologies associated with nuclear energy power systems, and functions as a nexus for the research and development of new reactor fuels and related materials. The site has deep historical roots in nuclear innovation — the DOME structure itself was previously used to develop and test EBR-II, an advanced sodium-cooled reactor whose predecessor design eventually led to the Integral Fast Reactor. That lineage forms the basis of TerraPower’s Natrium, a 345-megawatt advanced sodium-cooled reactor currently in development.
For more background on the DOME facility’s design and mission, read our earlier coverage: NRIC’s DOME is a purpose-built test bed at INL for real-world testing and development of advanced microreactor technologies, and NRIC’s DOME officially declared “open for business” by the American Nuclear Society.
Antares Microreactor Moves Toward Criticality Testing
The DOME opening coincides with significant momentum for at least one private developer already working within INL’s framework. Antares, a company developing its own microreactor design, recently received approval from the Department of Energy for its Documented Safety Analysis — a key regulatory milestone. Antares is now moving closer to a criticality test of its microreactor at INL, a step that would mark a significant proof-of-concept achievement for commercially developed advanced reactors in the United States.
The convergence of DOME’s opening and Antares’ regulatory progress signals that East Idaho is rapidly becoming the nerve center of America’s advanced nuclear energy renaissance. INL’s role as the nation’s primary nuclear research laboratory positions Bonneville County and the surrounding region at the forefront of what energy analysts and policymakers increasingly describe as a critical national security and energy independence priority.
Idaho has long been home to nuclear firsts — INL generated the world’s first usable nuclear electricity in 1951 — and DOME represents a continuation of that tradition, this time aimed squarely at enabling private industry to move advanced reactor concepts from design to operational demonstration faster than ever before.
What Comes Next
With DOME now officially open, industry partners will be able to bring their privately developed microreactor designs to INL for real-world testing and data collection to support regulatory verification and licensing. Antares remains among the most closely watched companies in the DOME pipeline, with its criticality test expected to be a major near-term milestone. Officials have signaled that DOME’s capacity to host multiple reactor developers makes it a long-term asset not just for Idaho, but for the United States’ broader strategy to compete globally in advanced nuclear energy. Bonneville County News will continue to monitor developments at INL and report on milestones as the DOME program advances. For statewide energy coverage, visit Idaho News.