- Valar Atomics reached criticality with its Ward250 small modular reactor in Orangeville, Utah, marking a key milestone in advanced nuclear deployment under a federal pilot program.
- The Department of Energy’s fast-track initiative, which also includes Antares Nuclear, is designed to test and validate reactor designs at smaller scale to accelerate commercial licensing toward the first operational SMRs in the United States.
- The achievement builds on earlier zero-power testing of Valar’s NOVA Core and reflects a broader national effort to rapidly move advanced reactor designs from demonstration to deployment.
After four decades of stagnation, the United States is seeing a resurgence of nuclear technology. At about 4:30 p.m. Thursday afternoon, Valar Atomics’ small modular reactor in Orangeville, Utah, reached zero-power fueled criticality.
The feat marks the first time a Department of Energy-authorized reactor has been built outside of a national laboratory.
Valar’s founder and CEO Isaiah Taylor, 27, sat with his team as they slowly guided their reactor to criticality, the point at which a nuclear reactor achieves a self-sustaining nuclear chain reaction.
Huddled in Valar’s futuristic-looking control center, Taylor’s team of engineers rocked back and forth through the process. The test began Wednesday evening.
Just four months earlier, the U.S. military airlifted the components of the reactor, dubbed the “Ward250,” across three Air Force C-17s.
When the C-17s touched down at Utah’s Hill Air Force Base in February, Energy Secretary Chris Wright told his audience that the rapid acceleration in nuclear development was largely thanks to executive orders demanding “tremendous reform.”
Valar has become the second of 10 companies chosen by the DOE to have its small modular reactor safely run all of its nuclear systems. The first was Antares Nuclear’s Mark-0, tested at the Idaho National Laboratory in Idaho Falls on June 4.
The DOE’s program puts Valar and Antares’ reactors one step closer to becoming the first operational small reactors in the U.S. Currently, the only operating SMRs include one in China and one in Russia.
Isaiah Taylor: ‘Our next goal is to make power ... before July 4′
Speaking from Valar’s site in Orangeville, Taylor thanked his team, Utah’s leadership and the Trump administration for helping Ward250 reach criticality.
“A few minutes ago, we took Ward250 critical,” Taylor said. “We have all been working insanely hard really for the last two years, but especially in the last week to prepare for this.”
He referenced the company’s founding on July 4, 2023.
“When I started this company less than three years ago, our guiding principle was that metal beats paper. There is an enormous amount of science that has been done in nuclear, an enormous amount of analysis. And all of these things are important and are helpful, but the biggest thing that was missing in nuclear energy was a mindset of learning and hardware,” Taylor said.
He continued, “We came into this with the humility to recognize that we don’t know exactly how the next generation of reactors will be built. We don’t have the ability to sit down and design the perfect reactor on paper. We certainly don’t have the ability to design the perfect factory line for the perfect reactor on paper. These things will be discovered through hardware iteration, and the execution in the hardware is what Atomics takes great pride in, and it’s what we demonstrated today.”
The company’s next goal, Taylor said, “is to make power in this reactor ... before July 4.”
The reactor is part of a pilot program
Shortly after returning to office, President Donald Trump set a goal to bring at least three reactors online by July 4, 2026.
To make it happen, the Department of Energy launched a new pathway to fast-track commercial licensing for advanced reactors.
When the first of its 10 selected companies, Antares Nuclear, achieved initial criticality at Idaho National Laboratory at the beginning of June, it became the laboratory’s first novel reactor design to achieve criticality in more than five decades.
Nuclear Regulatory Commission chairman Ho Nieh previously described the Energy Department’s reactor pilot project to the Deseret News.
“They’re doing smaller scale tests on their designs. And the idea is that you build it on a smaller scale, test it, get some data about how the reactor operates, then you take that data and analyze it and refine the design further,” he said.
Eventually, “a company like Valar can take that design and move it into commercial licensing through the NRC,” Nieh said.
What does it mean to reach criticality?
A reactor reaches criticality when it achieves a self-sustaining nuclear chain reaction.
Valar’s NOVA Core reached zero-power criticality last November at Los Alamos National Laboratory in New Mexico.
NOVA used the same fuel, moderator and reactivity-control scheme as Ward250, effectively allowing them to validate their physics models ahead of Wednesday night’s test.
The Valar Atomics team gathered to watch
The closer Ward250 got to criticality, the more packed its control room became.
Willem Kriel, who previously told the Deseret News that he came out of retirement and postponed a lengthy fishing trip to help lead Valar’s engineering team, stood patiently to the side.
Jess Housekeeper, Valar’s director of Utah operations, helped manage the process. Muhammad Shahzad, the former president and CFO of Relativity Space, an aerospace manufacturer, stood behind him. Shahzad serves as Valar’s president and CFO.
In the final stretch toward criticality, Utah Rep. Celeste Maloy joined the team.
The employees who couldn’t fit in the control room watched a livestream of the test in their warehouse.
“As a company, Valar has hired an enormous amount of extremely talented people who have Ph.D.s, who have been in nuclear engineering companies, who have built some of the most impressive projects in the last 25 years,” Taylor previously told the Deseret News.