HALEU nuclear fuel: History and prospects

High-Assay Low-Enriched Uranium (HALEU) nuclear fuel is a type of nuclear fuel enriched to a higher uranium-235 isotope content than the conventional low-enriched uranium (LEU) fuel used in pressurized waterreactors (PWRs) and boiling waterreactors (BWRs).

History of HALEU fuel

The development of HALEU technology began in the USA in the 2010s, in response to the need to improve nuclear reactor performance, particularly in terms of safety, durability and energy efficiency. The first prototype reactors using this fuel were designed in the late 2010s and early 2020s (1).

In the 2020s, several countries began actively pursuing the development of this technology. The USA, Canada, Russia, France, China and other countries have undertaken research and development projects to improve the performance and economics of their nuclear reactors using this advanced fuel (2).

Characteristics of HALEU

HALEU is characterized by a uranium-235 isotope content of between 5% and 20%, compared with 3% to 5% for conventional LEU (3). This higher fissile isotope content gives HALEU several advantages over LEU:

  1. Increased energy density: HALEU enables higher energy density, which means that reactors can produce more energy for the same volume of fuel (4). This reduces reactor size, extends fuel life and improves overall energy efficiency.
  2. Improved safety: HALEU technology enables nuclear reactors to be operated with greater safety margins, thanks to better heat management and lower reactivity in abnormal situations (5). This reduces the risk of nuclear accidents and contributes to public confidence in this energy source.
  3. Operational flexibility : HALEU reactors can be designed to operate at higher power levels and be more adaptive to variations in energy demand (6). This operational flexibility facilitates the integration of intermittent renewable energy sources, such as wind and solar power, into the power grid.
  4. Reducing nuclear waste: HALEU can significantly reduce the volume of nuclear waste produced, thanks to more efficient use of uranium and better management of the fuel cycle (7). This reduction in nuclear waste makes it easier to store and manage over the long term.

High-Assay Low-Enriched Uranium projects

According to the International Atomic Energy Agency (IAEA), several nuclear reactor projects using HALEU technology are currently under development worldwide (8). The most advanced projects include :

  • The Molten Salt Reactor (MSR) developed by Terrestrial Energy in Canada, which should be operational by the end of the 2020s (9).
  • GE-Hitachi’s PRISM sodium-cooled fast reactor (NFR) in the USA, scheduled to start construction in the 2020s (10).
  • EDF’s high-temperature reactor (HTR) project in France, scheduled for commissioning by 2030 (11).
  • China is also developing a supercritical water reactor (SCWR) using HALEU fuel, with a planned commissioning date in the 2030s (12).

Worldwide investment in HALEU technology is increasing, reflecting growing interest in this technology. According to a market study published in 2021, the global HALEU market is expected to grow at a compound annual growth rate (CAGR) of 4.9% between 2021 and 2026, reaching a value of $4.6 billion by 2026 (13).


HALEU nuclear fuel technology offers several advantages over conventional LEU fuel, notably in terms of energy density, safety, operational flexibility and nuclear waste reduction. With several nuclear reactor projects using HALEU currently under development, and market growth expected in the coming years, this technology looks promising for the future of nuclear power.

Challenges to the large-scale deployment of HALEU technology include the establishment of a fuel supply chain, regulation and certification of new reactors, and public acceptance. Nevertheless, if these challenges are successfully met, HALEU could play a key role in the global energy transition to more sustainable, lower-carbon energy sources.


  • (1) US Department of Energy, “Advanced Reactor Demonstration Program,” 2020.
  • (2) World Nuclear Association, “Advanced Nuclear Power Reactors,” 2021.
  • (3) US Nuclear Regulatory Commission, “High-Assay Low-Enriched Uranium (HALEU) Fuel,” 2021.
  • (4) Oak Ridge National Laboratory, “High-Assay Low-
  • Enriched Uranium (HALEU) Nuclear Fuels,” 2019.
  • (5) IAEA, “Challenges and Opportunities for Advanced Nuclear Technologies,” 2018.
  • (6) B. Forget et al, “Advanced reactors with high-assay low-enriched uranium fuels: A technical review,” Progress in Nuclear Energy, vol. 123, 2020.
  • (7) World Nuclear Association, “Nuclear Fuel Cycle Overview,” 2021.
  • (8) IAEA, “Advanced Reactors Information System (ARIS),” 2021.
  • (9) Terrestrial Energy, “Integral Molten Salt Reactor (IMSR),” 2021.
  • (10) GE-Hitachi, “PRISM: Powering the Future,” 2021.
  • (11) EDF, “The High-Temperature Reactor (HTR) project,” 2021.
  • (12) X. Cao et al, “Preliminary design of the 1000 MWth SCWR core with HALEU,” Annals of Nuclear Energy, vol. 152, 2021.
  • (13) Mordor Intelligence, “High-Assay Low-Enriched Uranium Market – Growth, Trends, COVID-19 Impact, and Forecasts (2021 – 2026),” 2021.
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