Oklo Completes Key Siting Milestone for First Commercial Nuclear Fast Reactor at INL

Advanced nuclear developer Oklo announced it has successfully completed borehole drilling for site characterization work at its Idaho National Laboratory (INL) site, marking a pivotal milestone as the company progresses toward constructing its first commercial Aurora Powerhouse—a liquid sodium–cooled fast reactor designed for scalable deployment.

The standard nuclear project development step, involved “drilling of several boreholes to comprehensive geotechnical assessments of subsurface conditions,” the company said on May 13. “These efforts help with validating site suitability, informing detailed engineering design, and securing the necessary permits for construction.”

Oklo’s Aurora Powerhouse is a vertically oriented, compact fast-spectrum reactor derived from the Experimental Breeder Reactor-II (EBR-II) that uses liquid sodium coolant and metallic high-assay low enriched uranium (HALEU) fuel. Designed for modular deployment, Oklo’s Powerhouse is tailored for markets that will require reliable, scalable, clean energy—like data centers, defense installations, and remote industrial facilities.

A First Commercial Deployment

The INL site will feature Oklo’s first commercial deployment—a 15-MWe (approximately 50-MWth) compact fast reactor—and may shape the company’s fleet strategy. In 2019, the DOE granted Oklo a site use permit providing access to a 40-acre parcel near INL’s Materials and Fuels Complex. INL later granted Oklo access to processed and treated used fuel recovered from the now-decommissioned Experimental Breeder Reactor-II (EBR-II) for use in the fast reactor project. Over the past year, Oklo has advanced through a series of milestones, including finalizing a memorandum of agreement (MoA) and an interface agreement (IAG) with INL, securing an environmental compliance permit, and progressing safety documentation for its Aurora Fuel Fabrication Facility, which will fabricate HALEU metallic fuel sourced from the former EBR-II reactor. The DOE approved Oklo’s Conceptual Safety Design Report for the fuel facility in October 2024,

The MoA and IAG with INL “ensure that our site development efforts are aligned with environmental standards and DOE coordination,” said Jacob DeWitte, co-founder and CEO at Oklo during the company’s latest earnings call Tuesday. The data gathered from the borehole drilling campaign “will directly support our combined license application to the [Nuclear Regulatory Commission (NRC)] and represents the final technical siting step ahead of submitting Phase 1 of our application,” he said.

The company is now “well-positioned to move into the next phase of licensing and infrastructure development with plans aiming for the plant to begin operations in late 2027 to early 2028,” DeWitte noted during the call on Tuesday.

Preparing a COLA

Oklo has said it plans to pursue licensing for the INL-sited project under the NRC 10 CFR Part 52 combined license (COL) framework, which authorizes both construction and operation of a nuclear facility. The company is currently undertaking a pre-application readiness assessment with the NRC to identify and address potential gaps ahead of submitting its formal COL application.

“We recently initiated Phase 1 of the pre-application readiness assessment for our Aurora INL powerhouse, reaching an important milestone in our licensing efforts with the NRC,” DeWitte noted. “This process, essentially, addressed rehearsal, enables the NRC and Oklo teams to align on scope and expectations ahead of our formal combined license application submission,” he said. “The goal is to surface and address feedback early, reduce challenges later, and build confidence and momentum as we move toward our formal COLA submittal. We expect we will soon receive an audit report from the NRC summarizing their feedback and recommendations, which we’ll incorporate into Phase 1 of the application.”

According to DeWitte, “The NRC’s feedback will be categorized as follows: Category A, Final Safety Analysis Report, or FSAR, gaps, where information required by regulation may be missing; Category B, items requiring additional information or further clarification or justification is needed; Category C, other observations, suggestions, or potential issues that could affect the efficiency of review if left unaddressed.”

He added: “We have worked diligently with the NRC to ensure a robust and complete application that should reduce Category A observations. However, every observation offers important insight into areas we can further develop to allow for an efficient and timely review of our Phase 1 COLA.”

DeWitte stressed that the feedback is “entirely expected and consistent with what other reactor developers have seen. These are clarifications and refinements, not fundamental application content flaws. This is exactly what the readiness assessment is designed to identify.”

He also underscored Oklo’s proactive licensing strategy: “Notably, Oklo is using this audit as an opportunity to test several key repeatable licensing pathways and expects valuable NRC guidance on how these novel approaches will best support rapid and cost-effective deployment.”

The company will target submitting the first phase of its COLA in a few months, with a full submission expected in late 2025. “We remain committed to submitting Phase 1 in the near term and Phase 2 later this year,” DeWitte confirmed.

—Sonal Patel is a POWER senior editor (@sonalcpatel, @POWERmagazine).