Conversion of Belgian facility marks the completion of more than a decade of work around the world to end the use of highly enriched uranium in facilities producing a vital medical isotope

WASHINGTON — The U.S. Department of Energy’s National Nuclear Security Administration (NNSA) reached a major nonproliferation milestone this week as it helped Belgium’s National Institute of Radioelements (IRE) convert their medical isotope production facility to use low-enriched uranium (LEU), instead of proliferation-sensitive highly enriched uranium (HEU). As a result, all major global molybdenum-99 (Mo-99) production facilities now use LEU targets.

This also means that all of the Mo-99 used in the United States is now produced without highly enriched uranium targets.

Jill Hruby
NNSA Administrator

Mo-99’s decay product, technetium-99m (Tc-99m), is used in over 40,000 medical procedures in the United States each day, including for the diagnosis of heart disease and cancer. Historically, Mo-99 was usually produced by irradiating HEU in nuclear reactors and then processing the irradiated material to extract the Mo-99. The uranium placed in the reactor for irradiation is known as a “target.” HEU is a proliferation-sensitive material that, if diverted or stolen, could be used as a component of a nuclear weapon. 

“Thanks to the hard work of the NNSA team and our partners, including Belgium’s IRE, all major Mo-99 producers can now perform their vital work without the use of proliferation-sensitive HEU targets,” said NNSA Administrator Jill Hruby. “This also means that all of the Mo-99 used in the United States is now produced without highly enriched uranium targets.”

Fulfilling a commitment made at the 2012 Nuclear Security Summit, NNSA provided financial and technical assistance to global Mo-99 producers for the conversion from HEU to LEU targets. These conversions were technically complex, requiring qualification of new LEU targets for irradiation in nuclear reactors, modification of specialized equipment for processing irradiated targets, and extensive reviews from both nuclear safety and medical regulators.

With help from NNSA, South Africa’s NTP Radioisotopes converted to LEU targets in 2017 and the Netherlands’ Curium converted in 2018. The fourth major Mo-99 producer, the Australian Nuclear Science and Technology Organisation, has always used LEU targets.

The progress made in converting global Mo-99 producers to LEU enabled the U.S. Secretaries of Energy and Health and Human Services to jointly certify in December 2021 that there is a sufficient global supply of Mo-99 produced without the use of HEU to meet the needs of U.S. patients. This certification triggered a ban on U.S. exports of HEU for foreign medical isotope production.

NNSA is also helping research reactor operators convert from HEU to LEU fuel; some of these reactors provide irradiation services for Mo-99 production. Of the six research reactors with a major role in Mo-99 production, five now use LEU fuel, and the sixth is expected to convert in 2026. LEU test assemblies are current being irradiated in this reactor as the final major technical step towards conversion.

Click here for more information on NNSA efforts to establish a reliable supply of Mo‑99 without the use of HEU.