TerraPower, the US-based nuclear reactor technology company backed by Bill Gates, is confident its first Natrium advanced plant will be built by 2030, but fuel supply remains a concern, the company said, according to Reuters.

Construction plans and licensing for the first plant at a retiring coal site in Kemmerer, Wyoming, are running smoothly, but the supply of high-assay low-enriched uranium (Haleu) for fuel is the greatest uncertainty when planning for deployment, TerraPower’s director of external affairs Jeff Navin said.

“We still think 2030 is our best bet as to when we can get things completed, but I can’t tell you today that I can account for every kilogram of Haleu that we will need, where it will come from, and when we'll have it, so that that is certainly something that still keeps us up at night,” Navin said.