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Four nuclear reactors hit a big milestone in the US | MIT Technology Review
Four US microreactor startups (Antares Nuclear, Valar Atomics, Deployable Energy, Aalo Atomics) achieved criticality—the ability to sustain a nuclear chain reaction—by July 4, 2026, meeting a Trump administration goal. Criticality is a technical milestone but does not mean the reactors are ready to generate grid electricity; companies now face cooling systems, regulatory approval, and significant engineering work before commercial deployment.
This Wire brief sits within Fusion42's coverage of Clean Energy and Energy Storage. Wire is Fusion42's founder-focused intelligence feed: each story is connected to the funds and startups it names — every one with a live profile on Raise or Scout — so founders can follow the capital and the momentum behind the headline rather than just the headline itself. Wire analysis is one of the live surfaces Arthur, Fusion42's AI co-founder, reasons over.
The Wire takeaway
You've just proved your reactor works at zero power; now you need to cool it, licence it, and actually generate electricity—all before 2027-2028. The regulatory path the NRC promised earlier this year is untested, and your startup timeline is already aggressive; regulatory delays will compress your cash runway harder than any technical problem.
Read the full story at technologyreview.com →
Topics: Clean Energy · Energy Storage · microreactors · nuclear-regulation · doe-pilot-program · grid-supply · startup-timelines