U.S. Department of Energy Secretary Chris Wright traveled to Idaho Falls on Thursday to mark a significant breakthrough in advanced nuclear reactor development, delivering a keynote address at the Mountain America Center and calling the moment a pivot point in the nation’s energy history.
The visit centered on a milestone achieved by Antares Nuclear’s Mark-0 advanced reactor at Idaho National Laboratory, which successfully completed a zero-power fueled criticality demonstration — making it the first advanced reactor to reach criticality under the DOE’s Reactor Pilot Program. The achievement also marks the first time in more than four decades that a privately developed non-light-water reactor has reached criticality anywhere in the United States.
A Historic Day at Idaho National Laboratory
Before taking the stage at the Mountain America Center, Secretary Wright toured Idaho National Laboratory, where he met with companies working to develop advanced reactor technologies. During the tour, Wright visited the DOME test bed and observed the Radiant reactor, which is currently under construction at the site.
The Mark-0 reactor holds a significant place in INL’s long history — it is the 53rd reactor built at the laboratory since its founding in 1951, a record that underscores Idaho National Laboratory’s decades-long role as the nation’s premier nuclear energy research institution.
Wright has now visited INL twice within the past six months, a signal of the current administration’s emphasis on nuclear energy as a cornerstone of both national security and domestic power production.
At the event, Wright framed the Mark-0 milestone in sweeping terms. “It is fitting that on the eve of our nation’s 250th anniversary, we are witnessing a historic moment for American energy,” he said. “For the first time in more than four decades, a new privately developed non-light-water reactor has reached criticality in the United States.”
He added that the moment would be remembered as a turning point. “This we will look back in history and remember this pivot, not just in America’s nuclear energy, but in America’s energy. Energy is life. Energy is national security.”
Commercial Power and the Road to 2027
The Mark-0 demonstration carries implications well beyond a single test. According to DOE, future commercial reactors based on advanced designs could begin generating electricity as early as 2027, a timeline that would represent a rapid transition from laboratory demonstration to grid-scale or off-grid power production.
The DOE has set an ambitious goal of having new microreactors operational by the time the United States celebrates its 250th anniversary — a deadline that adds symbolic weight to the milestone reached in Idaho Falls this week.
Potential uses for these next-generation microreactors are broad and include military installations, data centers in need of reliable power, remote communities that currently rely on expensive fuel shipments, and even space missions. The diversity of applications reflects growing interest across both the public and private sectors in compact, flexible nuclear power systems that can operate outside the traditional utility grid model.
Idaho National Laboratory has long been at the center of efforts to develop such technologies, and the laboratory’s expanding research partnerships — including collaborations with universities and private companies — continue to reinforce its position as a national hub for advanced nuclear innovation.
What Comes Next
With the Mark-0 criticality demonstration now complete, attention will shift toward next steps under the DOE’s Reactor Pilot Program and the broader timeline for commercial deployment. Industry observers and energy analysts will be watching closely to see whether the 2027 target for commercial electricity production from advanced reactor designs remains on track.
For Idaho Falls and the surrounding Bonneville County region, events like Thursday’s keynote reinforce the area’s strategic importance to the nation’s energy future. Idaho National Laboratory remains one of the largest employers in East Idaho, and continued federal investment in advanced nuclear programs stands to benefit the local economy and workforce for years to come.
Additional coverage of Idaho energy and nuclear policy developments is available at Idaho News.