DOE confirms Aalo-X as the fourth advanced reactor project to achieve criticality
Private companies often receive the majority of the credit when a project has been executed successfully, but the materialization of an initiative is multifaceted, with several bodies involved throughout. The government is expected to be responsible and maintain fairness with regard to the projects that it approves of. With the clean energy transition now fully underway, nations are prioritizing projects that take them a step closer to reaching their clean energy targets and eliminating carbon emissions. In the U.S., the DOE recently confirmed Aalo-X as the fourth advanced reactor project to achieve criticality.
Unpacking the role of the U.S. Department of Energy in approving Aalo-X
The Aalo-X refers to a 10 MWe experimental, sodium-cooled fast reactor that is currently under development by Aalo Atomics. It is located in the Idaho National Laboratory (INL). It operates as a full-scale prototype for the company’s modular nuclear power plants, which are purpose-built to provide power directly to energy-intensive AI data centers.
The United States’ dominance in the nuclear energy landscape means that companies have the freedom to invest in experimental projects and resources that will maintain the nation’s position at the top of the hierarchy. Interestingly, the Aalo-X project tests more than just the nuclear core.
It is specifically designed to validate the company’s civil construction technology. By operating a full-scale prototype connected to a 10 MW turbine, the Aalo-X allows the company to display the entire power generation process.
The Department of Energy facilitates another massive victory in the nuclear sector
The Department of Energy deserves a tremendous amount of credit for how it has inspired companies to pursue and execute projects that will reduce carbon emissions. In this case, the DOE was able to celebrate another win for the American nuclear renaissance. It was revealed that as part of the U.S. Department of Energy Reactor Pilot Program, Aalo Atomics’ test reactor, Aalo, was able to complete a zero-power fueled criticality demonstration.
The demonstration occurred at Idaho National Laboratory and is now officially recognized as the fourth DOE-authorized advanced reactor to reach the criticality milestone, surpassing the July 4th goal that President Trump outlined in his May 4, 2025, executive order.
The United States was able to break records in the nuclear energy sector even before the integration of advanced technology into the sector. U.S. Energy Secretary Chris Wright stated the following after the milestone was reached:
“Last month I toured the Aalo facility at Idaho National Laboratory and was impressed by the company’s determination to successfully demonstrate their technology by the Fourth of July. President Trump asked for three advanced reactors to be authorized and achieve criticality by the 250th anniversary of our great country.”
Understanding how the latest nuclear-based milestone influences future projects
Aalo-X is now part of a growing list of successful advanced reactor designs. It shines a light on the consistent progress and momentum reached by participants of the DOE’s Reactor Pilot Program and the Nuclear Energy Launch Pad initiative. In June, Antares Nuclear’s Mark-0 reactor, Valar Atomics’ Ward 250, and Deployable Energy’s Unity achieved criticality.
For the last few years, there was a feeling that the nuclear sector of the U.S. was becoming stagnant or complacent because of the dominance that the nation has. However, the success of the Department of Energy Reactor Pilot Program as of late serves as valid proof that the U.S. is capable of executing groundbreaking projects that create blueprints for competing nations.
Looking ahead: How important will the nuclear sector be in the clean energy transition?
The fourth criticality of a DOE-authorized reactor design exceeds what doubters believed American reactor developers were capable of in response to President Trump’s precedent-setting directive. The Reactor Pilot Program allows the certification and construction of first-of-a-kind advanced reactor designs for demonstration.
The overall and broader vision for Aalo-X is to create a pathway for the Aalo Pod, a 50 MWe standardized power plant expected to roll out for commercial deployment in 2028.
Prince is a versatile writer focused on energy, automotive, environmental, and general news topics. He makes complex technical and policy issues clear, engaging, and accessible for a broad audience.
