The Department of Energy has approved Oklo Preliminary Documented Safety Analysis for its Aurora powerhouse project at the Idaho National Laboratory (INL) under DOE’s reactor pilot program.
Oklo broke ground for its Aurora-INL reactor in September 2025.
DOE’s goal under the pilot program is to have at least three test advanced reactors reaching criticality by July 4. Oklo was the sole company to have two of the 11 projects selected for the program.
The approval of the safety analysis is a major step for the Santa Clara, Calif.-based nuclear company’s Aurora-INL reactor, Oklo said in a Thursday press release. It also represents a detailed review of the preliminary safety basis for the reactor, which includes the project’s hazard analysis, accident analysis, safety controls and design commitments, the company added.
“This approval represents an important milestone for Aurora-INL and helps establish a foundation for future Aurora deployments,” said Jacob DeWitte, co-founder and CEO of Oklo. “Aurora-INL is helping show how advanced reactors can move through real safety review, real construction, and ultimately into commercial licensing.”
Oklo joins other companies to hit this milestone under the reactor pilot program. Antares Nuclear is thus far the only company to hit zero-power criticality. Aalo Atomics is the only other company to have its documented safety analysis approved for its test reactor.
The company said the Aurora-INL will be its first planned fast fission power plant. The Aurora powerhouse is a sodium-cooled fast reactor that uses metal fuel and builds on the design of the Experiment Breeder Reactor-II (EBR-II).
The company was granted access to recovered fuel from the EBR-II following a DOE launched in 2019, according to the release. Oklo also received a site-use permit at INL for its Aurora powerhouse.
Additionally, Oklo’s subsidiary Atomic Alchemy is developing the Groves Isotope test reactor near Lockhart, Texas. Oklo’s subsidiary had its nuclear safety design agreement approved by DOE for the Texas test reactor in March.
Parallel to the company’s work under the reactor pilot program, Oklo is developing its Aurora Fuel Fabrication Facility in Idaho where it will fabricate the initial fuel assemblies for Aurora-INL from EBR-II fuel. According to the release, DOE’s Idaho Operations Office approved Aurora Fuel Fabrication Facility’s preliminary design safety analysis in December 2025, making it the first facility to be approved under DOE’s fuel line pilot program.
The fuel line program serves as a supplementary program to the reactor pilot activities and looks to establish a domestic nuclear fuel supply chain for testing the new advanced reactors.