Inside Oklo’s audacious plan to turn leftover weapons-grade plutonium into a nuclear bridge fuel

Since the first American nuclear power plant came online at the end of 1957, reactors had been built as bespoke, billion-dollar behemoths, designed to pump out hundreds of megawatts of electricity to offset the high up-front construction costs with greater economies of scale.

Oklo, the no-revenue $12 billion nuclear power startup, is trying to take a different approach, with smaller “microreactors” making it easier to ramp up power.

What really makes Oklo stand apart is the design of the reactor. Rather than using water as a coolant like all of the 94 commercial reactors in operation in the US, Oklo intends to use liquid sodium metal. With a coolant that could reach much higher temperatures, Oklo could burn through more of the toxic material that makes the half-life of nuclear waste take centuries to decay.

Sherwood reported about a fascinating new play in that strategy: while American enrichment companies scramble to build the supply chain for the high-assay, low-enriched uranium fuel for these next-generation reactor startups, Oklo thinks it has come up with another option: plutonium.

During the Cold War bomb-making era, the US government stockpiled plutonium for use in atomic weapons, and still has tons of the stuff lying around. Its long-lived radioactive waste makes plutonium particularly toxic. And Oklo revealed it wants to use that extra plutonium in storage to power its reactors.

The US Department of Energy had planned to take as much as 20 metric tons of plutonium, mix it with sand and kitty litter, and bury the material in the desert in New Mexico.The agency halted its disposal process in May, and in August, the Energy Department announced a program to make the material available for reactor companies.

The Takeaway

Oklo is in the running to get some. Depending on how much plutonium the company can secure, it could produce enough fuel to generate 2.5 gigawatts of electricity, equal to the power demands of nearly 2.5 million American households.

There are other potential sources of plutonium, too. The United Kingdom is planning to dilute and bury its stockpile. Japan, meanwhile, has its own inventory in storage. Between the two countries is as much as 150 tons of material, representing potentially another 10 to 16 gigawatts. Up