A landmark structure that helped define American nuclear history in the 1960s has taken on a new role at the forefront of next-generation energy technology. The Experimental Breeder Reactor-II dome at Idaho National Laboratory, located near Arco, has been refurbished and repurposed as the world’s first purpose-built test facility for fueled microreactors — a milestone that supporters say positions Idaho at the center of a global energy race.
The 100-foot-tall dome, a fixture of INL’s Materials and Fuels Complex, completed an extensive overhaul to transform it into a secure testing environment where private companies can bring their microreactor designs, gather experimental data, and pursue the regulatory approvals needed for commercial deployment.
A Race Against the Clock — and the World
Project teams at INL didn’t just complete the transformation — they finished it a full year ahead of the original schedule, driven by mounting national demand for advanced nuclear energy solutions. Brady Orchard, project director at the Materials and Fuels Complex, credited the accelerated pace to a broad collaborative effort.
“That required extensive support from over 300 individuals at MFC constructors,” Orchard said, adding that close coordination with industry partners on procurement timelines made the compressed schedule achievable.
Behind heavily shielded doors, the facility now provides a controlled, state-of-the-art environment for reactor developers to run tests that would be impossible to conduct elsewhere. Curtis Neilson, the DOME technical program manager, described the facility’s core mission as providing reactor companies with the hard data they need to move from concept to licensed product.
“It provides a robust test bed for those developers to come in and test their systems,” Neilson said, “obtaining the vital experimental data they need to support licensing and the ultimate deployment of their new advanced reactor concepts.”
The urgency behind the project reflects a broader strategic reality: the United States is competing internationally to deploy microreactors that can power remote military installations, strengthen disaster-resilient infrastructure, and bring reliable electricity to off-grid communities. Whoever leads in testing and licensing these technologies will likely lead in deployment — and INL’s refurbished dome puts Idaho squarely in that competition.
Economic Ripple Effects Already Reaching Idaho Falls
The facility’s impact is already being felt beyond the INL campus. Brett Tomer, director of the National Reactor Innovation Center, said the program has become a direct driver of business growth in eastern Idaho, with multiple reactor development companies establishing a local presence in response to the testing opportunities available at the dome.
“I know of at least five offices that have opened up because of our program,” Tomer said, noting that the companies are bringing employees who are relocating to live and work in the Idaho Falls area.
That kind of private-sector investment — drawn by a federally anchored research facility — represents exactly the kind of economic development Idaho communities have pursued through INL’s expanding role in advanced energy research. The laboratory has long been the region’s anchor employer, but the microreactor test bed signals a new chapter that could attract a sustained wave of private nuclear technology firms to Southeast Idaho.
INL’s footprint as a driver of statewide economic activity is a subject covered regularly at Idaho News, where the laboratory’s research missions and federal funding have drawn ongoing attention.
Heritage Preserved Alongside Innovation
Despite the sweeping modernization of the dome structure, the facility has not entirely shed its past. The original EBR-II control room, dating to the 1960s, has been preserved as part of the transformed site — a nod to the generations of scientists and engineers whose work inside those walls helped establish Idaho’s nuclear legacy.
That legacy now serves as a foundation rather than a relic. INL plans to support its first reactor demonstration projects at the facility beginning this summer.
For more on infrastructure developments across the region, including ongoing water quality planning for Rock Creek, Bannock County News continues tracking the public works and energy projects shaping Southeast Idaho’s future.
What Comes Next
Idaho National Laboratory is expected to begin hosting initial microreactor demonstration projects at the dome facility this summer. As private companies finalize testing partnerships and continue opening regional offices, INL officials anticipate the program will grow significantly in the coming years. The National Reactor Innovation Center will oversee operations and coordinate with industry partners as licensing data from the test bed begins informing federal regulatory reviews of next-generation reactor designs.