The test reactor, near Lockhart in Caldwell County, Texas reached first criticality in August, less than a year after groundbreaking. It is one of 11 advanced reactor projects selected by the US Department of Energy (DOE) in August 2025 for the Nuclear Reactor Pilot Program, a programme aiming to expedite the testing of advanced reactor designs under a DOE authorisation pathway.

The DOE has now cleared the final operations hold point for the reactor - also known as Groves-1 - allowing the facility to advance into its research, testing, and training phase. This will help Oklo prepare the teams and systems needed to support the efficient delivery and operation of future nuclear projects, the company said. Operating experience from Groves-1 will directly inform Groves-2 Forge, Oklo's planned isotope production and processing pilot facility, which is part of the DOE's Nuclear Energy Launch Pad initiative to promote the rapid development and implementation of advanced nuclear technologies by private industry.