Oklo said the permit is an important step towards commercialising advanced fission technologies and is the first issued for a non-light water reactor.
The permit is a critical milestone on the path towards deployment of Oklo’s 1.5-MW Aurora plant, which company co-founders Jacob DeWitte and Caroline Cochran unveiled last month.
“The system itself is designed to build on the really tremendous legacy of metallic fuels that were developed in this country for decades,” Mr DeWitte said at the event.
The Aurora will generate both usable heat and electricity, run for at least 20 years on one load of fuel and operate without the need for water, he said. The plant can also recycle fuel and ultimately convert nuclear waste to clean energy.
Oklo, which is solely venture-funded and backed primarily by US-based investors, recently announced that it successfully demonstrated prototypes of a metallic fuel at INL for the Aurora reactor. It said it had fabricated prototypes with multiple fuel elements reaching production specification.
To fabricate the fuel, zirconium and uranium was melted, casted, taken apart and then examined, Mr DeWitte said.
Oklo would use high-assay low-enriched uranium (Haleu) fuel. However, I common with many other advanced reactor developers, the lack of reliable access to Haleu remains a challenge – one that Congress has set its sights on addressing. The sooner Oklo can “have access to be able to work with that, the faster we’re going to be able to actually get something built,” Mr DeWitte said.
Haleu fuel has many advantages that improve reactor performance. Because the fissionable isotope U235 is more concentrated in Haleu fuel, the fuel assemblies and reactors can be smaller, which is one reason why many small modular reactor designs will run on Haleu. The reactors do not need to be refueled as often, and they can achieve higher burnup rates, which means less fuel will be required and less waste will be produced.
The company is preparing to submit its first licence application for the plant and is targeting the construction of a commercial unit in the early to mid-2020s.
Mr DeWitte said reactors of Oklo’s size are geared especially toward use in remote areas, such as on islands or in Alaska, that often rely on expensive and emitting diesel fuel for energy.