Leading the charge: INL’s role in advancing HALEU production
Idaho National Laboratory is playing a key role in helping the U.S. Department of Energy meet near-term needs by recovering HALEU from federal inventories, providing critical support to help lay the foundation for a future commercial HALEU supply chain. INL also supports coordination of broader DOE efforts, from material recovery at the Savannah River Site in South Carolina to commercial enrichment initiatives.
INL is tackling this challenge in part by providing small quantities of HALEU to companies with near-term research needs and by converting used fuel from the Experimental Breeder Reactor-II into larger amounts of usable HALEU for first-of-a-kind advanced reactors. This work is intended to help meet the nation’s near- and mid-term HALEU needs while the long-term commercial HALEU supply chain is being established.
“We are trying to satisfy the immediate needs of the nuclear industry with our focus on short-term and mid-term goals,” said Josh Jarrell, director of INL’s Fuel Cycle Science and Technology Division.
Shortly after the nuclear energy industry identified the need to quickly develop a sustainable HALEU supply, INL began providing HALEU for small research activities, such as collecting performance data on new HALEU fuel types.
While recovery of uranium from EBR-II used fuel has been ongoing for many years, that activity was accelerated to ensure HALEU was available to advanced reactor companies to meet their desired schedules.
The importance of HALEU
HALEU reguli cast from downblended EBR-II spent nuclear fuel. The numbers on the metal tray correspond to numbered locations in the graphite crucible used to form the reguli. (Photo: INL)
INL researchers have processed HALEU reguli by dissolving the metal in acid, purifying it by solvent extraction, and precipitating and converting the purified HALEU into solid forms. From left to right are solid UO4, UO3, and U3O8. (Photo: INL)
While the existing U.S. nuclear fleet uses uranium oxide fuel enriched up to 5 percent with uranium-235, HALEU is enriched between 5 percent and 20 percent. HALEU is essential for numerous advanced reactor designs—including fast reactors, molten salt reactors, and microreactors—and is a key component in TRISO fuel. It can also significantly enhance the performance of current reactors.
There are two ways to obtain HALEU: enriching uranium to the desired level or downblending high-enriched uranium from existing stockpiles that may have been recovered from used fuel.
Before making capital-intensive investments in HALEU production capabilities, potential suppliers need confidence that there will be a reliable market for their product. In the near term, reactor developers require HALEU for research, fuel qualification, and first cores for demonstration reactors. Longer term, deployment of advanced reactors requires a much larger and continuous supply of HALEU to meet commercial industry needs.
“A domestic supply of HALEU is critical to the deployment of advanced reactors,” said Jess Gehin, associate laboratory director for INL’s Nuclear Science and Technology directorate. “There is an increased urgency as imports from Russia are no longer viable to support advanced reactors’ initial cores.”
While INL plays a pivotal role by jump-starting the HALEU supply chain through its recovery and reuse efforts, several companies, including American Centrifuge Operating, General Matter, Louisiana Energy Services, and Orano Federal Services, are gearing up for commercial HALEU production.
Enabling innovation
Cross section of 12-mm fuel compact containing dozens of individual TRISO particles. (Photo: INL)
In recent years, INL has provided HALEU for research and development use by repurposing surplus materials from various legacy programs. This effort involves identifying and processing suitable scrap HEU into the appropriate fuel forms for further irradiation testing, characterization, and data collection.
In 2023, INL facilitated the transfer of approximately 6 kilograms of HALEU to BWX Technologies for TRISO fuel development for the company’s BWXT Advanced Nuclear Reactor (BANR) project.
More recently, Southern Nuclear loaded nuclear fuel with uranium-235 enriched up to 6 percent—higher than the usual 3–5 percent enrichment—into Vogtle-2 to test it through irradiation. The fuel was developed as part of the DOE’s Accident Tolerant Fuel program. The pellets, which also include additives expected to enhance safety performance, were derived from uranium oxide (UO2) powder first prepared by INL.
Bridging the gap
In addition to directly providing small amounts of HALEU for research needs, INL is identifying surplus inventories of uranium scrap for conversion into useable HALEU.
“This [National Nuclear Security Administration]-led scrap recovery program, which INL participates in, supports companies like Westinghouse for its eVinci microreactor, providing essential materials to continue their projects,” said Corey Shannon, who oversees INL’s HALEU scrap recovery efforts. “Over 80 kilograms of legacy fabrication scrap and other uranium forms are currently being stabilized, characterized, repackaged, and shipped for further processing.”
Along with the scrap recovery efforts that may provide hundreds of kilograms of HALEU, INL is going to provide reactor developers with thousands of kilograms of HALEU from EBR-II used fuel recovery efforts funded through the DOE Office of Nuclear Energy.
EBR-II operated at Argonne National Laboratory–West (now part of INL) from 1964 to 1994 and ran on high-enriched nuclear fuel. As part of the deactivation of the reactor and management of the sodium-bonded used fuel inventory, the irradiated elements have been undergoing a treatment process to neutralize the reactive sodium. This process enables the separation of uranium from the sodium and fission products, facilitating the recovery of the uranium.
“When EBR-II shut down, there were 3 metric tons of used fuel containing [HEU], which is valuable because it can be recovered and diluted down to HALEU levels,” said Mike Patterson, program manager for used fuel treatment and disposition at INL’s Materials and Fuels Complex.
The recovered HEU is diluted with lower-enriched uranium (a process known as downblending) to create HALEU. Treating the EBR-II used fuel elements with this method creates high-quality HALEU that meets the needs of some advanced reactor developer designs.
“Since 2019, we expanded from four-day weeks to seven-day weeks and eventually to a 24-hour schedule for four days a week,” said Patterson. “We will complete the EBR-II driver treatment by the end of 2028, aligning with the HALEU demand schedule.”
Going commercial
In helping bridge the gap between the industry’s near-term needs and a fully fledged HALEU industry, one of the key challenges is the compatibility of EBR-II HALEU with various reactor designs. While the material is ideal for fast reactors like those developed by Santa Clara, Calif.–based Oklo, there are some impurities that require additional processing for use with light water reactors or thermal reactors.
“The current material from EBR-II seems to be a good fit for Oklo’s reactor concepts but may not be compatible with some other advanced reactor applications,” said Patterson.
Once the EBR-II driver fuel elements have been treated, INL will have recovered enough material to produce just under 10 metric tons of HALEU, half of which is allocated to Oklo for use in its Aurora Powerhouse on the INL Site.
To increase the range of fuels and thus the number the nuclear developers that could benefit from the remaining HALEU, INL demonstrated in 2019 a “polishing” process on 3 kilograms of HALEU that purified and cleaned the material. The process also converted it from a metal into an oxide, making it suitable for broader applications, including as a feedstock for TRISO fuel.
The polished material was then sampled, and those samples were sent to BWXT, which confirmed that the material may be received at its facility for fuel processing.
“Now, INL is scaling this polishing process up and will use a new glovebox line to produce hundreds of kilograms of purified HALEU oxide per year beginning in 2028,” Jarrell said.
In April, the DOE announced conditional commitments to provide HALEU to five U.S. nuclear developers through its HALEU Availability Program. These commitments will help developers meet their near-term fuel needs and advance innovative American nuclear technologies as a step closer to commercialization.
In June, Centrus Energy announced a milestone in its contract with the DOE: a shipment that marked the first significant domestic production of HALEU.
These investments aim to advance commercialization, with national laboratories playing a supporting part.
“The role of national laboratories like INL is critical in bridging the gap between reactor design and market readiness,” said Jarrell. “By providing essential HALEU supplies while the commercial HALEU supply chain is being established, national labs ensure that the nuclear industry can innovate and advance, ultimately leading to an abundant supply of affordable and reliable energy.”
Donna Kemp Spangler is a senior communication strategist for GAIN (Gateway for Accelerated Innovation in Nuclear) at Idaho National Laboratory.
About Idaho National Laboratory
Battelle Energy Alliance manages INL for the U.S. Department of Energy’s Office of Nuclear Energy. INL is the nation’s center for nuclear energy research and development and also performs research in each of the DOE’s strategic goal areas: energy, national security, science, and the environment. For more information, visit inl.gov. Follow us on social media: Facebook, Instagram, LinkedIn, and X.