Home › Intelligence › What is HALEU?

The short answer

HALEU (high-assay low-enriched uranium) is uranium enriched so that the fissile isotope uranium-235 makes up between 5% and 20% of the fuel. That range sits above the 3–5% enrichment used in conventional light-water reactors, but below the 20% threshold that would classify it as high-enriched (weapons-grade) material.

The higher enrichment means more energy per fuel assembly, longer core life, and smaller cores — exactly the properties advanced reactor designers need to build compact, high-temperature, passively safe systems.

5–20%
U-235 enrichment range for HALEU
3–5%
Conventional LWR enrichment
1,900+ kg
HALEU produced by Centrus to date
0
US commercial HALEU production before the DOE program

Why does HALEU matter for SMRs?

Most advanced reactor designs in development — including sodium fast reactors (TerraPower Natrium, Oklo Aurora), high-temperature gas-cooled reactors (X-energy Xe-100), fluoride-salt-cooled reactors (Kairos KP-FHR) and several others — are engineered around HALEU fuel. The fuel’s higher fissile density lets them achieve high power output from a much smaller core, with longer refueling intervals that improve economics for remote sites, industrial campuses and AI data centers.

Without HALEU, these reactors cannot start. With no commercial U.S. source of the material for years, fuel availability became a gating factor for nearly every advanced nuclear project — a point underscored by developer dependencies on DOE’s HALEU availability program.

Where does HALEU come from?

HALEU is produced by enriching uranium hexafluoride (UF6) using gas centrifuges. The U.S. had effectively lost commercial enrichment capability for this material. The Department of Energy’s $2.7 billion domestic enrichment program changed that trajectory:

  • Centrus (NYSE: LEU) — the first NRC-licensed U.S. HALEU production facility, at Piketon, Ohio. Completed the demonstration contract with 1,900+ kg of HALEU UF6, then signed a $900M contract (up to $1.07B with options) in June 2026 to transition to commercial-scale operation. Source: Power Magazine
  • American Centrifuge Operating (ACO) — Centrus’ subsidiary operating the Piketon cascade. Source: Centrus SEC filing
  • DOE awards — $900M each to ACO (Centrus) and General Matter for HALEU production, plus an LEU award, under the $2.7B enrichment push. Source: ANS News
Why so few suppliers? Enrichment is a capital-intensive, dual-use, NRC-licensed industry. Russia has dominated commercial HALEU supply; the U.S. and allies are racing to build domestic alternatives — a strategic response that now touches defense, energy security and AI infrastructure at once.

Who buys HALEU?

Advanced reactor developers are the primary offtakers. Signature relationships include:

  • X-energy × Centrus (Aug 2026): a definitive agreement for LEU and HALEU enrichment services to support the initial fuel needs of X-energy’s 11.5 GW Xe-100 pipeline, with prepayments. Source: X-energy · World Nuclear News
  • Oklo × Centrus (2025): a letter of intent for fuel for Aurora Powerhouse deployment in Southern Ohio. Source: Oklo
  • TerraPower, NuScale and others also depend on HALEU availability for reactor timelines. Source: EdWealth

Where is this heading?

Centrus targets at least some HALEU production by the end of the decade and ~12 metric tons per year after 2030, with the first new commercial capacity expected online around 2029. X-energy’s TRISO-X fuel fabrication campus in Oak Ridge, Tennessee — the first NRC-licensed commercial TRISO fuel facility in U.S. history — turns that HALEU into fuel for the Xe-100 fleet. Source: USNIC · World Nuclear News

For anyone tracking SMR deployment timelines — data center power teams, EPC firms, investors — the HALEU supply chain is the critical path to watch. See our full supply chain tracker.

Sources: World Nuclear Association · Power Magazine · Centrus SEC 8-K · X-energy · ANS News