HALEU (High-Assay Low-Enriched Uranium)
Uranium enriched to between 5% and 20% U-235. Several advanced reactor designs (including many SMRs) require HALEU fuel, which is not yet commercially available at scale in the U.S.
Why It Matters
HALEU availability is a bottleneck for deploying next-generation reactors. DOE is working to establish a domestic HALEU supply chain independent of Russian enrichment.
Related Topics
Related Terms
Enrichment
The process of increasing the concentration of uranium-235 (the fissile isotope) in uranium fuel. Most commercial reactors need 3-5% enrichment (natural is 0.7%). Advanced reactors may need HALEU (5-20%).
Uranium
A naturally occurring radioactive element used as fuel in nuclear reactors. Natural uranium is 99.3% U-238 and 0.7% U-235. Most reactors require enrichment to 3-5% U-235.
Small Modular Reactor (SMR)
A nuclear reactor with electrical output under 300 MW (vs. 1,000+ MW for conventional reactors), designed for factory fabrication and site assembly. Key designs include NuScale VOYGR, TerraPower Natrium, and X-energy Xe-100.