Texas facility part of company’s broader effort to build US production capabilities
US advanced nuclear technology company Oklo announced that its Groves Isotope Test Reactor in Lockhart, Texas, reached first criticality after achieving a controlled, self-sustaining nuclear chain reaction at low power.
The company said the milestone comes less than a year after groundbreaking and follows US Department of Energy (DOE) authorisation through the DOE Reactor Pilot Program, an accelerated federal initiative to fast-track the testing and demonstration of advanced nuclear reactor designs.
“Groves offers a concrete blueprint for future advanced nuclear deployment as the fastest fully privately financed and built reactor project of its kind,” the company said.
“Today, Oklo proves that advanced reactors can be built, started, and operated faster than anyone thought possible and shows the world that America can build nuclear again.”
Oklo co-founder and chief executive officer Jacob DeWitte said Oklo developed Groves from a greenfield site on private land, completed full-scale civil excavation and construction, manufactured or commercially procured all components, including fuel, and developed its operating programmes in-house.
“Taken together, we believe these accomplishments establish a new benchmark for the Reactor Pilot Program and set the stage for the future of advanced nuclear deployment at scale,” he said.
Groves is part of Oklo’s broader effort to build domestic isotope production capabilities.
Oklo, which is backed by OpenAI founder Sam Altman and is also developing nuclear fission power plants and nuclear fuel technologies, said such isotopes could eventually support cancer care, manufacturing, scientific research, space exploration and national security.
Many important isotopes are sourced from overseas suppliers or produced in aging facilities, creating supply risks for US hospitals, industry, researchers, and government users.
By starting with a pilot facility, Oklo’s isotopes business has developed operating procedures, evaluated reactor system performance, and will validate production processes as it attempts to build domestic isotope production at commercial scale in the US.
Groves is a low-power fission reactor with a maximum thermal power capacity of 100 watts.
Unlike many next-generation advanced reactors, including Oklo’s own flagship Aurora Powerhouse design, which rely on harder-to-source high-assay low-enriched uranium (Haleu), Groves was intentionally designed to use standard, commercially available low-enriched uranium.
