Oklo's Groves reactor reaches criticality less than a year after groundbreaking

Oklo's Groves Isotope Test Reactor has achieved first criticality less than a year after groundbreaking, marking another milestone for the U.S. Department of Energy's effort to accelerate testing of advanced nuclear technologies.

The Groves facility in Caldwell County, Texas, achieved a controlled, self-sustaining nuclear chain reaction earlier this month after receiving DOE startup authorization in July. DOE said Groves became the fifth DOE-authorized advanced reactor to reach criticality this summer.

OkloGroves is not a commercial power reactor. DOE describes the facility as a zero-power critical assembly with a maximum operating power of 100 watts. It is designed to give Oklo experience designing, constructing and operating a reactor while supporting the company's plans for future commercial-scale production of radioisotopes for medical, industrial, space, defense and research applications.

The distinction is important because Oklo is separately developing its Aurora fast-reactor technology to generate electricity. Groves does not demonstrate commercial power production, but the company views the project's development process as a model it can draw from on future deployments.

Oklo said it developed Groves on private land, completed the civil construction, manufactured or commercially procured its components and fuel, and developed its operating programs in-house. The company received DOE startup authorization just over 10 months after breaking ground and reached criticality roughly two weeks later.

"Reaching criticality in less than a year is an incredible milestone for our team," Oklo co-founder and CEO Jacob DeWitte said.

Groves is one of 11 projects from 10 companies initially selected for DOE's Reactor Pilot Program. The program was created to expedite testing of advanced reactor designs using DOE's authorization process, with participating companies responsible for the costs of designing, building, operating and eventually decommissioning their test reactors.

For Oklo, the significance of Groves now lies largely in what comes next. The company says the project allowed it to establish suppliers, operating procedures, safety programs and construction experience that can inform future projects. Whether that experience can translate into similarly compressed timelines for larger commercial reactors remains a much bigger test.