Belgium’s Institute for Radioelements (IRE), a key producer of molybdenum-99 (Mo-99) and iodine-131 (I-131) widely used in nuclear medicine, has complete conversion of its production process to low-enriched uranium (LEU). This has ended the use of highly enriched uranium (HEU), which is seen as a proliferation risk.
IRE said conversion to a LEU process represents the culmination of years of work and collaboration between its R&D, production, safety, quality assurance and regulatory teams IRE has developed an entirely new industrial process for supplying Mo-99 and I-131 to healthcare professionals, without impacting the site's production capacity. This would not have been possible without the upstream collaboration of the research reactors which irradiate the uranium targets or downstream customers who had to modify the application files of their Mo-99 and I-131-based drugs and have them approved.” IRE CEO said: "IRE will continue to innovate in order to contribute even better to saving lives thanks to nuclear medicine applications, while increasing the safety of our processes and our facilities."
The Director-General of the Euratom Supply Agency and Co-chair of the European Observatory on the Supply of Medical Radioisotopes Agnieszka Kazmierczak said completion of the conversion is an important milestone in global efforts to minimise HEU use. “The close cooperation between various actors involved in this endeavour allowed to advance the goal of both: nuclear security and security of supply of the most vital medical radioisotopes.”
IRE thanked the Belgian Federal Agency for Nuclear Control (FANC), “which has followed and accompanied it at all the milestones of this long development in terms of nuclear security and safety”. Preliminary consultations with FANC began in 2015. IRE in 2016 asked to amend its licensing conditions to enable the switch. The following year, the permit for the development of LEU production was granted by Royal Decree. FANC and its technical subsidiary Bel V approved the start of Mo-99 production using LEU in April 2020 and IRE produced its first batch of Mo-99 using an LEU target in May. This was completed with uranium targets irradiated in Belgium’s BR2, a 100MW high-flux materials test reactor at SCK-CEN in Mol. In 2021, IRE announced that its first commercial deliveries of I-131 based on the irradiation of LEU targets had started.
The US Department of Energy’s National Nuclear Security Administration (DOE/NNSA) provided financial and technical support for the conversion. “For decades, access to life-saving medical isotopes depended on the shipment of proliferation-sensitive nuclear material across continents,” said NNSA Administrator Jill Hruby. “With IRE’s production facility converted to LEU, all major producers across the Mo-99 industry can perform their vital work without HEU targets.”
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.
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. The sixth, Belgium's BR2, is expected to convert in 2026. LEU test assemblies are being irradiated in this reactor as the final major technical step towards conversion.
Image: Production of molybdenum-99 using low-enriched uranium at Belgium’s Institute for Radioelements (courtesy of IRE)
