UUSA first applied for a license amendment to increase its allowed enrichment level from 5.5 percent to just under 10 percent in November 2023. In December 2024, the NRC approved the company’s license amendment request pending an operational readiness review and the authorization that has now been granted. Now, UUSA expects its initial production of LEU+ before the end of the year, with first product deliveries to a fuel fabricator in 2026.
What’s it for? Currently operating light water reactors could seek NRC approval to use fuel above the current enrichment limit of 5 percent, which could allow reactors to run longer operating cycles between refueling outages. Some new reactors are being designed to use LEU+ as fuel, while many others seek high-assay low-enriched uranium, and LEU+ can enter the supply chain for HALEU-fueled reactors as a feedstock for HALEU enrichment operations.
While the HALEU label can technically be assigned to uranium enriched to between 5 and 19.75 percent U-235, it is often defined as between 10 and 19.75 percent U-235, because it’s at 10 percent that a different set of regulatory requirements kicks in. A fuel cycle facility enriching uranium above 10 percent U-235 is considered a Category 2 facility and is subject to more stringent NRC security regulations than facilities with Category 3 licenses like UUSA’s enrichment operations in New Mexico.
A Category 2 HALEU enrichment facility that receives LEU+ feedstock can produce HALEU by performing fewer separative work units (SWUs) than it must if starting with natural uranium, which means such a HALEU enrichment facility could have a smaller footprint and operate more efficiently.
Getting ready for LEU+: Preparing for LEU+ production required more than 100,000 hours of work, more than 30 new items relied on for safety (IROFSs), and more than 250 modifications to license basis and program documents, according to UUSA.
UUSA produces about one-third of the enriched uranium required to power the U.S. commercial nuclear power plants and is currently the only commercial enricher operating in the United States. The company is working to expand its production capacity by 15 percent by mid-2027, with two new centrifuge cascades successfully brought on line ahead of schedule and on budget already this year.
“Our dedicated employees have worked diligently to deliver this new capability for the benefit of our current and future customers and to support the long-term success of the U.S. nuclear industry,” said John Kirkpatrick, managing director of UUSA. “With LEU+ as an option for fueling America’s reactors, current nuclear plant operators can realize new gains in operations and efficiencies that will support even stronger performance by the country’s existing reactor fleet, and advanced reactor developers will have a reliable option to fuel their new designs.”
Official word: In a letter sent by the NRC to UUSA chief nuclear officer Paul Lorskulsint confirming the approval, NRC acting regional administrator Julio F. Lara wrote that “this NRC authorization is based on the results of operational readiness reviews that the NRC has performed over the past year.”
Lara added that the NRC has confirmed that necessary changes have been made “to support the safe production LEU+ in accordance with the requirements of your license.” NRC inspections confirmed changes including that IROFSs have been implemented, that operators have been trained on the new and changed IROFSs, and that new IROFSs will segregate LEU+ from areas that have not yet had LEU+ controls implemented and authorized, including, for example, the site’s recycling systems.
A separate license amendment request, which was approved by the NRC in July, covers the introduction of LEU+ into the site’s recycling systems.
