Oklo

Nuclear Energy · Isotopes · Advanced Reactors

Milestone

Oklo Wins DOE Startup Authorization for Groves Isotope Reactor

The clearance lets Oklo load fuel and chase first criticality on a timeline regulators used to measure in years, not months.

• Oklo received U.S. Department of Energy startup authorization for its Groves Isotope Test Reactor near Lockhart, Texas, under the DOE's Reactor Pilot Program, clearing the way for fuel loading, startup testing, and first criticality.
• Groves is a low-power test reactor designed to demonstrate reactor design, build, and operations, establishing the experience Oklo needs to build future commercial-scale domestic isotope production facilities.
• Oklo says the reactor reached substantial completion in 229 days, moving from groundbreaking to DOE startup authorization in just over 10 months.
• The privately financed, roughly $23 million facility was built on private land inside a 538-acre innovation hub in Lockhart, Texas, with all systems and fuel sourced commercially or made in-house.
• Groves is one of several reactors under DOE's Reactor Pilot Program, which aimed to reach criticality on at least three test reactors by July 4, 2026; Antares Nuclear, Valar Atomics, Deployable Energy, and Aalo Atomics reactors already achieved criticality this program cycle.
• Because Groves used a commercial-scale build process rather than a national-lab test setup, Oklo can now point to concrete cost and schedule data as it tries to replicate the same siting-to-operation playbook for its planned commercial isotope and power reactors.