$24B Nuclear Startup Splits First Atom — For Medicine, Not The Power Plants It Still Can't Build

Oklo, the Sam Altman-backed small-modular-reactor startup, announced its Groves Isotope Test Reactor in rural Texas achieved criticality — the first chain reaction from any Oklo reactor. The low-power unit supports the company's medical isotope business, not its electricity-generating ambitions, and was built on private land in under a year. Oklo still lacks NRC approval to construct its flagship 75-megawatt power reactors, making this a practice run rather than a power play. It is the fifth of ten DOE Reactor Pilot Program companies to reach criticality this year.