Four US Microreactors Achieve Criticality Milestone

Four US companies achieved criticality in their prototype microreactors by July 4, 2024, meeting a goal set by the Trump administration for the nation's 250th birthday. This milestone signifies that the reactors can sustain a chain reaction, a crucial step in their development. The achievement is particularly notable given the rapid progress, with companies like Valar Atomics, Antares Nuclear, and Aalo Atomics being founded as recently as 2023. Antares Nuclear was the first to reach criticality with its Mark-0 test reactor in June, followed by reactors from Valar Atomics, Deployable Energy, and Aalo Atomics. Aalo Atomics achieved its milestone in the early hours of July 4. These microreactors are significantly smaller than the large light-water reactors currently powering the grid. The Reactor Pilot Program, established by the US Department of Energy, has been instrumental in fast-tracking the development of these prototype reactors by offering them land and support from national laboratories. The program selected 11 reactor projects in August. While achieving criticality is a significant technical accomplishment, it does not mean the reactors are ready to generate electricity for the grid. The successful development of these advanced nuclear technologies is seen as a positive development for increasing electricity supply and supporting emissions-free energy solutions amid growing global energy demands and climate change concerns. The speed at which these companies have progressed is impressive for an industry often characterized by large-scale projects with budget and timeline overruns.