Key Takeaways:
Oklo's Groves test reactor received Department of Energy startup authorization in just over 10 months from groundbreaking, a timeline the company says is the fastest for a privately funded, full-scale reactor in US history.
Oklo Inc. secured startup authorization from the US Department of Energy for its Groves Isotope Test Reactor in Texas under the Reactor Pilot Program, the company said Thursday. The approval allows the company to load nuclear fuel, conduct startup testing, and proceed toward first criticality — the point at which a reactor sustains a controlled nuclear chain reaction.
"This facility marks the fastest time that we are aware of to go from greenfield to substantial completion for a full-scale, privately funded and sited reactor in history," Jacob DeWitte, co-founder and chief executive officer of Oklo, said. "By building on a greenfield site on private land, performing full-scale civil excavation and construction, and procuring fuel and all major components commercially, we demonstrated that the advanced nuclear industry can move at a pace that many did not believe possible."
The Groves reactor is a low-power test reactor using low-enriched uranium — enriched to less than 5%, compared with the 3% to 5% typical of conventional reactors — designed to produce isotopes for potential use in cancer care, manufacturing, scientific research, space exploration, and national security. Most radioactive isotopes used in the US are currently produced overseas. The project was privately financed, built on private land, and assembled using commercially sourced systems alongside components manufactured by Oklo.
The authorization is a milestone for Oklo's broader ambitions. The company began its regulatory journey for the Aurora Powerhouse, a sodium-cooled fast reactor SMR (small modular reactor, typically under 300 MWe and designed for factory fabrication), with the Nuclear Regulatory Commission in November 2016. It submitted its combined license application in March 2020 and is still awaiting a commercial license. Under the Reactor Pilot Program, certain portions of DOE approval are expected to transfer directly to the NRC approval process, potentially expediting the Aurora timeline.
What the Groves experience means for Aurora
The Groves project gives Oklo a repeatable template. The company said it can "repeat the experience with demonstrated experience in siting, building, commissioning, and operating its commercial reactors in the future." Management believes the systems, supplier relationships, and operating programs developed through Groves can be applied to future projects, lowering execution risk and improving deployment timelines.
The Reactor Pilot Program, enacted by executive order in 2025, instructs the NRC to create an expedited pathway for reactors that have been safely tested by the DOE, with an 18-month deadline to evaluate and approve new construction and operation licenses. Three other test reactors have already achieved initial criticality under the program: Antares Nuclear's Mark-0 in early June, Valar Atomics' Ward 250, and Deployable Energy's Unity demonstration reactor on July 1.
Competitive landscape
Oklo is one of several publicly traded companies pursuing distinct reactor technologies. NuScale Power, the first company to receive NRC approval for a small modular reactor design, is working on projects in the US and Romania, targeting power for utilities, industrial facilities, and AI-driven data centers. The broader advanced nuclear sector is moving from design and testing toward licensing and commercial deployment, with policy support from the DOE's pilot framework.
For investors, the key question is whether Oklo can replicate the Groves timeline for Aurora. The company has completed three of five steps in its DOE regulatory review for construction and operation, with an NRC audit in progress. If the Aurora process moves as quickly as Groves, Oklo could find itself months or years ahead of schedule on its commercial reactor plan. Oklo shares trade on the New York Stock Exchange under the ticker OKLO.
This article is for informational purposes only and does not constitute investment advice.
