The global market for radioactive materials used in medicine is at risk of experiencing a supply problem over the coming years, as a limited number of aging reactors that produce them will have to cope with increasing demand worldwide. The issue recently came to the fore as the simultaneous outages of three medical isotope production facilities in Europe resulted in the global shortage of technetium 99m, a radioisotope used in some 80 per cent of all nuclear medicine procedures in the world. An unexpected outage extension of a reactor in Canada resulted in a similar shortage less than a year earlier.
The IAEA is contributing to avert a potential global medical emergency by helping research reactor operators run their facilities safely and reliably. A collection of recommended practices that have been demonstrated to work for operators worldwide was recently published by the IAEA and is now available on its website. Focusing on an array of operational management areas including: risk-informed maintenance and planning; configuration management; communication and operating experience; and corrective action management. The publication draws on the experience of 12 reactor operators and institutions of different sizes and from various geographical locations.
"The reliance on a limited number of research reactors and, specifically, the age of these reactors is closely linked to the issue of the global shortage of medical isotopes and could lead to serious consequences," says Ed Bradley, a nuclear engineer from the IAEA Research Reactors Group in the Division of Nuclear Fuel Cycle and Waste Technology. Bradley also developed the report on "Optimization of Research Reactor Availability and Reliability". "No new isotope production facilities have been commissioned for several decades, and it will take time before new reactors start producing isotopes. Modifications to currently operating facilities are also being developed, but these will also take some time to fully implement. This issue will remain with us for several years to come."
"Anyone interested in isotope supply over the short- to interim-term must address the reliable operation of these ageing facilities as a priority," says Bradley. "At the IAEA, we gathered recommended practices directly from research reactor operators with demonstrated performance excellence. Our aim was to make sure that practical advice is made available to operators to help ensure facilities operate to produce medical isotopes as required."
The existing fleet of research reactors worldwide is aging fast. Two-thirds of them are already over 40 years old. IAEA experts continue to work on issues specific to aging research reactors and how to extend their operational life.
Medical isotopes and radiation sources are produced when target material, usually High Enriched Uranium (HEU), is irradiated with neutrons coming from the controlled fission taking place in a research reactor. Atoms in the target capture some of those neutrons thus become heavier isotopes.
Just five research reactors produce most of worldwide demand for molybdenum 99, from which technetium 99m is fabricated. These are the High Flux Reactor in Petten, the Netherlands; BR2 at Mol in Belgium; Osiris at Saclay, France; NRU at Chalk River, Canada; and the Safari-1 at Pelindaba, South Africa. These facilities range in age from 42 to 51 years. A sixth reactor, Australia's recently constructed OPAL at Lucas Heights, is expected to commence molybdenum 99 production soon. Two research reactors in Canada - each dedicated to isotope production and expected to produce enough molybdenum to account for the bulk of global supply - were recently cancelled due to technical challenges.
Several countries have expressed an interest in building modern research reactors, often seen as a stepping stone to a full-blown nuclear power programme in addition to other capabilities such as isotope production. However, it can take ten or more years from the planning phase for research reactors to become operational and "teething" issues during the early years of operation can add additional, unanticipated challenges.
Projects to initiate molybdenum production from an existing facility, not originally conceived for that purpose, can also take five or more years to become operational depending on available equipment and facilities at the specific reactor site.