Researchers at Idaho National Laboratory in early 2023 manufactured commercial-grade high-assay low-enriched uranium (HALEU) fuel pellets to the specifications of a General Electric accident tolerant fuel design, INL announced November 21. A team working at INL’s Experimental Fuels Facility at the Material and Fuels Complex fabricated about two dozen uranium dioxide pellets using HALEU enriched up to 15 percent U-235.
The pellets in question: The pellets were made with a sintering technique like that used to make conventional light water reactor fuel. They are also the size and shape of LWR fuel pellets, but uranium enriched to 15 percent U-235 puts these pellets well above the typical 5 percent upper limit for today’s LWR fuel. After putting the pellets through a series of tests to assess their properties and impurities, the research team plans to fabricate another 100 to 150 to support testing of GE’s specialized cladding material in INL’s Advanced Test Reactor.
The project is funded by the Accident Tolerant Fuel Program of the Department of Energy’s Office of Nuclear Energy. Westinghouse, GE, and Framatome are all currently working with the DOE through that program to develop and commercialize new cladding and fuel designs to increase plant performance and enhance the safety response to severe accidents in today’s reactors before the end of the decade. This work could also improve the performance of future advanced reactors.
INL capabilities: Nuclear News spoke with Adrian Wagner, INL group lead for advanced manufacturing and ceramic fuel fabrication, in a full-length interview published in September. Wagner and his colleague Jorgen Rufner, an electric field assisted sintering scientist/engineer and group lead for advanced manufacturing, explained that INL can provide lab-scale manufacturing of test quantities of customized fuel for industry and government partners but is not equipped to make fuel on a commercial scale.
“The goals of the collaboration were to establish additional fuel fabrication capabilities at INL and fabricate higher enriched uranium dioxide samples (greater than 5 percent) for higher powered experiments in the Advanced Test Reactor at INL,” Wagner told NN.
Jennifer Watkins, an INL nuclear fuels and materials scientist, works with Wagner and lead the project to produce the test pellets. “INL is the best place in the U.S. to develop fabrication processes for unique and novel fuel concepts,” she said. “INL has one of the widest ranges of feedstock options at a variety of enrichment levels and an extremely flexible DOE-based enrichment license allowing for adaptability to user needs.”
Demonstrating the manufacture of uranium dioxide HALEU fuel pellets “opens the door for other types of HALEU—both metallic and ceramic—and highlights INL’s ability to tailor enrichments to customer and experiment requirements,” according to INL. Next up could be nitride, boride, carbide, and silicide fuels, which permit higher uranium densities.