NRC denies Oklo licence application

Oklo submitted its application in March 2020 for the advanced reactor, to be built at the Idaho National Laboratory site. The NRC accepted the application that June, using a novel, two-step approach to docketing the application to allow Oklo to fill in identified information gaps in it before developing a review schedule. Although the company subsequently submitted reports and supplementary information on several topics in July and October 2021, the information supplied was insufficient to close those gaps, the NRC has concluded.

"Since Oklo submitted its application almost 22 months ago, our engagement with the company has included multiple information requests, audits and public meetings," said NRC Director of the Office of Nuclear Reactor Regulation Andrea Veil. "We thoroughly considered Oklo's proposals for satisfying our safety requirements."

"Oklo's application continues to contain significant information gaps in its description of Aurora's potential accidents as well as its classification of safety systems and components," Veil said. "These gaps prevent further review activities. We are prepared to re-engage with Oklo if they submit a revised application that provides the information we need for a thorough and timely review."

The Aurora design is a fast neutron reactor that uses heat pipes to transport heat from the reactor core to a supercritical carbon dioxide power conversion system to generate electricity. Using metallic HALEU fuel, the Aurora 'powerhouse' produces about 1.5 MWe and can also produce usable heat. Oklo's was the first combined construction and operation licence for an advanced fission technology to be accepted for review by the US regulator.

The NRC has made no findings on the safety of the design and said its denial was not a determination on the safety, security, or merits of the application. "The NRC staff's denial of the Aurora custom combined licence application is without prejudice and does not preclude Oklo from addressing the information gaps the NRC staff has identified and resubmitting a licence application in the future," it said.

"We are eager to continue moving forward on not just this project with the NRC, but also other projects we are already engaged on with the NRC, including other budgeted application submittals." Oklo told World Nuclear News. "Our combined licence application was the first ever accepted for an advanced plant, so there are many new things for all to learn from and work through to support a successful review, and it provides a foundation from which we can supply additional information and continue work with the NRC. The application was accepted as an important step for the nation's interest, and we are continuing our work on advanced fission unabated as key to a clean energy future."

Updated: This article was updated on 10 January to include a comment from Oklo.