Deployable Energy has successfully brought its Unity demonstration reactor to nuclear criticality at Idaho National Laboratory, marking another major step in the United States Department of Energy (DOE) drive to accelerate next-generation nuclear technologies.
The milestone was achieved through the DOE’s Nuclear Energy Launch Pad initiative. The zero-power-fuelled criticality demonstration makes Unity the third DOE-authorised advanced reactor to achieve nuclear criticality before the July 4 deadline established by President Donald Trump’s May 2025 executive order.
The achievement also completes a key federal objective aimed at accelerating innovation across the US nuclear sector.
With Unity now joining Antares Nuclear’s Mark-0 reactor and Valar Atomics’ Ward 250 reactor, the United States has become the first nation to bring three different advanced microreactor designs to criticality within a single month.
The milestone highlights the pace of development under the DOE’s Reactor Pilot Program and the expanded Nuclear Energy Launch Pad initiative.
Secretary of Energy Chris Wright hailed the successful test as a historic moment for US nuclear energy: “Last week, I had the opportunity to see the Unity demonstration reactor firsthand and meet with the talented teams from Deployable Energy, INL and DOE whose work made this historic moment possible on the eve of our nation’s 250th anniversary.
“America’s nuclear renaissance is underway because of President Trump’s bold vision and ambitious goals. Yesterday, we accomplished a significant milestone on a timeline many thought was unachievable.
“Advanced nuclear technologies like Unity will help power the next generation of American industry, strengthen our energy security, and ensure the United States remains the world’s nuclear innovation leader.”
What is nuclear criticality?
Nuclear criticality is the point at which a nuclear reactor becomes self-sustaining. At this stage, every nuclear fission event produces, on average, one additional fission event, allowing the chain reaction to continue at a constant rate without increasing or decreasing.
Reaching criticality does not mean a reactor is producing significant amounts of electricity or operating at full power. During a zero-power criticality test, reactor power remains extremely low, allowing engineers to verify reactor behaviour, confirm safety systems and validate computer models before moving on to higher-power operations.
Criticality testing is one of the most important milestones during the commissioning of any advanced reactor, providing confidence that the reactor performs as designed under controlled conditions.
Unity reaches a key advanced reactor milestone
The Unity demonstration was carried out at Idaho National Laboratory under the Nuclear Energy Launch Pad programme, which is managed by the National Reactor Innovation Center.
The initiative is designed to help developers rapidly demonstrate first-of-a-kind nuclear technologies by streamlining regulatory authorisation and providing access to national laboratory expertise and infrastructure.
Unlike commercial power production, Unity’s latest demonstration was conducted at zero power. The objective was to validate the reactor’s design by demonstrating that it could safely sustain a nuclear chain reaction under tightly controlled conditions before progressing to future testing and development.
As the first project within the Nuclear Energy Launch Pad initiative to reach this stage, Unity demonstrates how access to specialised facilities and technical support can reduce the time needed to complete fundamental reactor experiments.
Bobby Gallagher, Co-Founder and CEO at Deployable Energy, added: “We are proud to be a part of this historic achievement and I want to express Deployable Energy’s gratitude to the administration for setting an audacious goal to have three reactors reach criticality before July 4, the DOE for ensuring our ability to meet this goal with safety, quality, and speed, and the Idaho National Laboratory for providing an incredible partnership in execution.
“I also want to thank my team and supply chain partners of dedicated professionals. We would not have been able to meet this moment without their brilliance, boldness, and grit.”
Accelerating US nuclear innovation
The Nuclear Energy Launch Pad represents the next phase of the DOE’s Reactor Pilot Program, with a focus on accelerating the demonstration of innovative reactor technologies.
By successfully bringing three distinct microreactor designs to criticality in rapid succession, the programme demonstrates the potential for national laboratories to help shorten development timelines while supporting the commercial deployment of advanced nuclear systems.
The latest achievement strengthens the US position in the development of advanced reactor technologies and reinforces broader efforts to expand domestic nuclear innovation.
