By Mackenzie Tatananni

Oklo surged Tuesday after the advanced nuclear start-up was tapped to participate in a federal program repurposing excess Cold War-era plutonium into reactor fuel.

Shares jumped after the Energy Department selected Oklo and four other nuclear companies for advanced negotiations under its Surplus Plutonium Utilization Program. The initiative aims to power nuclear reactors using plutonium from the U.S. government's stockpile.

Oklo stock jumped 6.7% to $70.29 on Tuesday. The benchmark S&P 500 gained 0.7%.

The start-up is exploring ways to use plutonium as a temporary "bridge fuel" while the U.S. builds out domestic supply chains for traditional fuels like high-assay low-enriched uranium.

The government has designated roughly 50 metric tons of plutonium as weapons-grade but excessive to national security needs. As a result, it has been tagged for disposal, though efforts are underway to repurpose it.

President Donald Trump signed an executive order last year directing the Energy Department to consider processing some of the plutonium for use in advanced nuclear reactors. The announcement Tuesday is a continuation of that work.

Just last month, Oklo partnered with Nvidia to leverage artificial-intelligence infrastructure in nuclear fuel research. Oklo CEO Jacob DeWitte told Barron's at the time that the agreement would "significantly accelerate" plutonium-bearing fuel work on Oklo's Pluto reactor.

Oklo has worked with Los Alamos National Laboratory to validate the reactor's design, which recycles nuclear waste into energy, using surplus plutonium from the federal stockpile. The highly radioactive material is held at several secure sites across the country, including at LANL.

Meanwhile, progress continues on Aurora, the company's first commercial nuclear facility, which is set to be constructed at the Idaho National Laboratory. The Nuclear Regulatory Commission approved Aurora's Principal Design Criteria -- a foundational rulebook for the plant's safety and performance standards -- earlier this month.

Write to Mackenzie Tatananni at mackenzie.tatananni@barrons.com

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May 26, 2026 09:55 ET (13:55 GMT)

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