Oklo's Groves-1 test reactor in Texas cleared by DOE for unrestricted operations
The US Department of Energy cleared the last operations hold point for Oklo's Groves-1, which reached first criticality in August. The reactor moves to research, testing and training.
The US Department of Energy (DOE) has cleared the final operations hold point for Groves-1, a test reactor built by Oklo near Lockhart in Caldwell County, Texas, world-nuclear-news.org reports. The reactor reached first criticality in August, less than a year after groundbreaking, and can now move into its research, testing and training phase world-nuclear-news.org
world-nuclear-news.orgworld-nuclear-news.orgOpen source ↗. Groves-1 is one of 11 advanced reactor projects selected by the DOE in August 2025 for the Nuclear Reactor Pilot Program.
The program aims to speed up testing of advanced reactor designs under a DOE authorisation pathway. In response to executive orders issued in May 2025, which called for at least three prototype reactors to reach criticality by 4 July 2026, the DOE revamped that pathway to streamline the process.
Regulatory pathway
New reactor designs for commercial use in the USA are reviewed and approved by the US Nuclear Regulatory Commission (NRC). Under the Atomic Energy Act, however, the DOE has the authority to approve reactor authorisations for research, development and demonstration. That authority is now used to let advanced reactor developers certify, build and test prototype reactors.
In October, the NRC finalised a rule that allows applicants to use analyses, test data and other information from DOE or Department of War (formerly the Department of Defense) reactor demonstration programmes in commercial licence applications. The NRC still evaluates the safety of proposed commercial projects independently world-nuclear-news.org
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Testing plans for Groves-1
Oklo said Groves-1 will serve as a training and qualification platform for nuclear personnel at future reactor deployments. Equipment testing will continue, including evaluations of control rod drive mechanism performance and reliability. The reactor will also be used for criticality and reactivity benchmarking that supports Oklo's isotope production capabilities and its engineering and design models.
The company also plans to test capabilities relevant to future isotope reactors and to its fast fission reactor, the Aurora powerhouse. According to Oklo, the data could also help improve fuel performance and power output in small and large light water reactors.
Operating experience from Groves-1 will inform Groves-2 Forge, Oklo's planned isotope production and processing pilot facility. It is part of the DOE's Nuclear Energy Launch Pad initiative, which promotes rapid development of advanced nuclear technologies by private industry world-nuclear-news.org
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Oklo CEO and co-founder Jacob DeWitte said that taking Groves-1 from greenfield to criticality in less than a year demonstrated what the team can accomplish. Acting Deputy Assistant Secretary for Nuclear Reactors Chimi Zacot said the Reactor Pilot Program reset the industry's expectations for how quickly advanced reactors can move from design to demonstration while upholding safety standards.
