Decades of nuclear energy research pay off in milestone nonproliferation achievement

When the U.S. Department of Energy’s (DOE) National Nuclear Security Administration (NNSA) announced that it had reached a major nonproliferation milestone this week, many at Argonne National Laboratory, a DOE national laboratory, felt a surge of pride.

Scientists and engineers at Argonne have been working for decades to help medical isotope production facilities around the world change from the use of highly enriched uranium (HEU) to the use of low-enriched uranium (LEU), which is much more difficult to use in a weapon. The successful conversion of Belgium’s National Institute of Radioelements (IRE) was the last step in completion of the effort.

“Our scientists and engineers work diligently to see problems solved and challenges overcome, and this is a moment when we can celebrate the impact of that diligence worldwide.” — Temitope Taiwo, director of Nuclear Science and Engineering, Argonne

“As a result of this accomplishment, all major global molybdenum-99 production facilities now use LEU,” said Temitope Taiwo, director of the Nuclear Science and Engineering division at Argonne. ​“Our scientists and engineers work diligently to see problems solved and challenges overcome, and this is a moment when we can celebrate the impact of that diligence worldwide.”

Molybdenum-99’s (Mo-99) 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. Argonne helped with these technically complex conversions, which included 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.

“It was good chemistry — not only re-evaluating the uranium processes from the ground up but also the chemistry between the IRE and DOE staff — that led to the successful conversion and manufacturing of this life-saving isotope,” said M. Alex Brown, a nuclear chemical engineer in Argonne’s Chemical and Fuel Cycle Technologies division.

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.

Argonne National Laboratory seeks solutions to pressing national problems in science and technology. The nation’s first national laboratory, Argonne conducts leading-edge basic and applied scientific research in virtually every scientific discipline. Argonne researchers work closely with researchers from hundreds of companies, universities, and federal, state and municipal agencies to help them solve their specific problems, advance America’s scientific leadership and prepare the nation for a better future. With employees from more than 60 nations, Argonne is managed by UChicago Argonne, LLC for the U.S. Department of Energy’s Office of Science.

The U.S. Department of Energy’s Office of Science is the single largest supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time. For more information, visit https://​ener​gy​.gov/​s​c​ience.