PRESS RELEASE3 MIN READ
Groves-1 to transition from reactor deployment demonstration to operating platform for research, testing, and training.
Groves Isotope Test Reactor (Groves-1) was taken critical in August 2026 under the U.S. Department of Energy Reactor Pilot Program, the first to do so under the program on private land.
LOCKHART, Texas--(BUSINESS WIRE)-- Oklo Inc. (NYSE: OKLO) (“Oklo” or “the Company”), an advanced nuclear technology company, today announced the U.S. Department of Energy (DOE) has cleared the final operations hold point for the Groves Isotope Test Reactor (Groves-1), allowing the facility to advance into its research, testing, and training phase. With the facility cleared for unrestricted operations, Oklo will test its capabilities relevant to future isotope reactors and Oklo’s fast fission reactors, the Aurora powerhouse.
Groves-1, under DOE authorization through the DOE Reactor Pilot Program (RPP), reached first criticality at low power less than a year after groundbreaking. The test reactor demonstrated the ability to engineer, construct, authorize, commission, and operate a full nuclear facility. Its next phase will build on this experience to help Oklo prepare the teams and systems needed to support the efficient delivery and operation of additional nuclear projects.
That preparation has already begun. During a recent reactor startup, operators wore eye-tracking glasses to record what they were looking at and for how long, giving the team data to improve the facility’s human-machine interface and inform future design choices. Groves-1 will also serve as a key training and qualification platform for nuclear personnel at future reactor deployments, alongside further equipment testing, including continued evaluations of control rod drive mechanism performance and reliability.
Additionally, Groves-1 will enable criticality and reactivity benchmarking operations that support Oklo’s isotope production capabilities, its engineering and design models, and potentially light water reactors and the large light water reactor fleet. The resulting data could also help improve fuel performance and power output in small and large light water reactors.
“Taking Groves-1 from greenfield to criticality in less than a year was an important demonstration of what our team can accomplish,” said Oklo CEO and co-founder Jacob DeWitte. “Now we're building on that experience by operating the reactor, testing new capabilities, and learning directly from the work. Those lessons can help us develop the people, systems, and processes needed as we advance additional isotope projects and Aurora powerhouses.”
“DOE’s Reactor Pilot Program reset the nuclear industry’s expectations for how quickly we can move from advanced reactor design to demonstration while upholding best-in-class safety standards,” says acting Deputy Assistant Secretary for Nuclear Reactors Chimi Zacot. “Successes like Groves-1's criticality are now paving the way for what comes next.”
Groves-1’s operating experience will directly inform Groves-2 Forge, Oklo’s planned isotope production and processing pilot facility selected under DOE’s Nuclear Energy Launch Pad initiative. Groves-2 Forge will integrate historically fragmented parts of the isotope value chain, combining reactor irradiation with hot-cell processing capabilities. Facility capabilities will include isotope separation, product recovery, packaging, and transportation, with initial focus on lutetium-177, an isotope used in targeted cancer treatments.
About Oklo Inc.: Oklo Inc. is developing fast fission power plants to deliver clean, reliable, affordable energy at global scale; establishing a domestic supply chain for critical isotopes; and advancing nuclear fuel recycling to convert used nuclear fuel into clean energy. Oklo was the first to receive a site use permit from the U.S. Department of Energy for a commercial advanced fission plant, was awarded fuel from Idaho National Laboratory, and submitted the first custom combined license application for an advanced reactor to the U.S. Nuclear Regulatory Commission. Oklo is also developing advanced fuel recycling technologies in collaboration with the U.S. Department of Energy and U.S. National Laboratories.