French and Belgian radioisotope production reactors will step into the breach to mitigate shortages of molybdenum-99 (Mo-99) when a Dutch reactor enters a mandatory shutdown in March 2010 in a strategy agreed by Europe's medical radioisotope producers.
A meeting between the Association of Imaging Producers and Equipment Suppliers (AIPES) and European producers of Mo-99 was held to find a way to keep a continuous supply of the isotope when the Netherland's High Flux Reactor (HFR) reactor shuts down. HFR supplies some 60% of Europe's Mo-99 but will have to shut down in March next year for lengthy repairs to end an ingress of tiny bubbles into its primary cooling system. Meanwhile, another one of the world's major Mo-99 suppliers, Canada's National Research Unit (NRU), has been off line since May 2009.
To help to avoid a worsening of the supply situation, the operators of Belgium's BR2 reactor have now agreed to add an extra irradiation cycle, while France's OSIRIS reactor and the French Nuclear Safety Authority have agreed to postpone scheduled maintenance operations by two months. "Thanks to this coordination, the new schedule allows to reduce from 15 to about 4 weeks, spread out over the year, the periods when a further reduction of Mo-99 production capacity would have occurred," according to AIPES.
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Mo-99 is supplied to hospitals to generate short-lived technetium-99m (Tc-99m), the most widely used medical radioisotope in the world. Tc-99m decays in a matter of hours. It is used in medical imaging applications, such as to diagnose cancer and heart disease, and is used in some 80% of all nuclear medicine procedures. However, as Mo-99 has a half-life of only 66 hours, hospitals require a reliable, steady supply of the isotope.
Over recent years world supplies of medical radioisotopes have been thrown into crisis when the reactors used to produce the isotopes have encountered problems. NRU underwent an extended unscheduled outage at the end of 2007 and has currently been off line since May 2009, and a period in 2008 saw key reactors in Belgium, Canada, France, South Africa and the Netherlands, undergoing refuelling and maintenance within weeks of each other.
Work is progressing at NRU, with operator Atomic Energy of Canada Ltd's (AECL) latest update reporting the arrival on site of the first set of specially developed welding tools and equipment for carrying out the weld repair required on the reactor vessel, and staff training and preparation for the initial welding almost complete.
Based on "the best evidence available", AECL says it currently anticipates the reactor will return to service during the first calendar quarter of 2010.
With both HFR and NRU slated for retirement around 2016, the only long-term solution will be investment in new research reactors. The University of Saskatchewan in Canada has proposed a replacement for NRU, while in the Netherlands a cabinet decision has backed the construciton of another reactor there. The licensing process for the Pallas reactor should begin before the end of this year.