First US Modular Reactor Reaches Criticality

Milestone in Nuclear Power

Antares, a startup focused on modular reactor technology, has successfully tested its reactor at the Idaho National Laboratory, achieving criticality for the first time in the US. This milestone is part of a broader initiative to accelerate nuclear power development, following an executive order from the Trump Administration.

The reactor utilizes a new fuel system called TRISO, which enhances safety by simplifying reactor design. Key features include:

• Self-sustaining reactions: Criticality indicates that the nuclear reactions are self-sustaining, although power generation has not yet begun.
• Advanced fuel design: TRISO pellets are encased in a robust ceramic shell, minimizing meltdown risks.
• Safety measures: The design incorporates a graphite sheath to slow escaping neutrons, reducing the risk of unstable isotopes.

While the current test reactor is not connected to power generation, it aims to validate modeling and generate safety data for future licensing applications. Full operational tests, including electricity generation, are anticipated next year, potentially paving the way for mobile nuclear reactors in collaboration with the Department of Defense and NASA.