At Idaho National Lab, reactor success and Trump’s nuclear program celebrated
U.S. Energy Secretary Chris Wright visited the Idaho National Laboratory on Thursday after the first new-age nuclear reactor to switch on in more than 40 years did so at INL earlier this month.
In an executive order issued in May 2025, President Donald Trump created the Reactor Pilot Program with the explicit goal to have three new advanced nuclear reactors reach criticality — the ability to maintain a self-sustaining chain reaction — by July 4, 2026. An “advanced nuclear reactor” utilizes innovative technology such as more efficient fuel, new coolant types, passive safety features, or smaller, modular sizes.
Regarding the July 4 goal, Wright asserted to CNBC in an interview Thursday morning, “We are gonna meet that.” He announced that Aalo Atomics had received approval to move forward on tests “with soon to be our third next-generation nuclear reactor to turn on, to go critical and maintain a sustaining chain reaction.”
Ahead of Wright’s visit, two reactors achieved criticality. Antares Nuclear crossed the finish line first with its advanced reactor design, the Mark-0, which was built and tested at INL. On June 4, the Mark-0 completed a zero-power criticality demonstration at the lab in Idaho Falls, making it “the first non-light water reactor to go critical in the United States in over 40 years,” Wright told CNBC.
Two weeks later, Valar Atomics’ advanced reactor design, Ward 250, achieved criticality at the Utah San Rafael Energy Lab in Emery County, Utah. The minivan-sized Ward 250 is the first reactor to be built outside of a national laboratory, as well as the first reactor to be transported by flight. The microreactor was transported between Air Force bases in California and Utah on a C-17, demonstrating its portability — but it was not loaded with nuclear fuel.
But having reactors create energy is not as easy as getting to criticality.
On Thursday afternoon, a series of speakers culminating with Wright delivered remarks to an audience that included representatives from the nuclear companies in the Department of Energy’s Reactor Pilot Program. The atmosphere was summed up best by Kyle Haustveit, undersecretary of energy, when he said, “This is the first time I’ve been able to pick a walk-out song before delivering remarks.”
INL Director John Wagner said they were on track to have three reactors go critical by July 4, and added that “several more will follow shortly thereafter.” Wagner mentioned that Radiant Nuclear was in the process of moving its Kaleidos reactor components into the DOME on INL’s campus for testing.
Looking toward the future, Wagner emphasized: “The goal was never just criticality. The goal is 400 gigawatts of nuclear capacity by 2050."
Wright was the last to speak. He reminded the audience of the transformative nature of nuclear energy in a post-World War II America.
“Within 2-2 ½ decades we launched the construction of over a hundred nuclear reactors across our country, quickly providing 20% of the United States’ electricity,” he said.
Idaho at the center of the history and future of nuclear energy
These zero-power criticality tests are an important step, but they leave one of the most innovative aspects of these new reactors untested: the cooling systems.
All commercially operated nuclear reactors in the U.S. use water as a coolant and rely on electrically operated pumps. Antares Nuclear’s Mark-0 employs sodium heat pipes that passively transfer heat away from the reactor core without using power. Liquid sodium near the core is heated up, turns into a vapor and rises to the top of the pipes, where it can emit heat and then condense back to a liquid, to begin the cycle again.
How a building will be constructed to deal with all of that emitted heat, and whether those systems will require electricity, remains to be seen.
Future tests on these advanced nuclear reactors at levels that will generate energy will also generate heat, putting their new cooling systems to the test.
When asked about the timeline to commercialization, Wright told CNBC, “I believe we’ll see the first electricity coming out of a small modular reactor, perhaps before the end of next year, and definitely within 2028, within the Trump administration.”
Idaho Lt. Gov. Scott Bedke was in attendance Thursday as well.
“This is the ground where America first lit a lightbulb with the atom, December 20th, 1951,” he said.
When nuclear fission in Idaho produced electricity for civilian applications for the first time in human history, it “proved that the atom could serve mankind instead of threaten it,” Bedke said.
Bedke praised Idaho’s nuclear legacy and looked toward its future when he said: “We have the land, the legacy, and the labor force, and we have the will. What we have always needed is a nation ready to meet us with that same conviction. And under this administration ... we have the proper partner.”