10 Nov (NucNet): Australia�s Opal research reactor has returned to full operation and will restart production of technetium 99m, a radioisotope used in some 80 per cent of all nuclear medicine procedures globally, later this month.

Opal�s restart follows a separate warning from the International Atomic Energy Agency (IAEA) that the global market for radiopharmaceuticals risks problems with supply in the coming years because the limited number of ageing reactors producing them will face increased demand.

Australia is currently importing technetium-99m which is more costly and subject to periodic interruptions of supply. The Australian Nuclear Science and Technology Organisation (ANSTO) said on 7 November 2008 that the replacement of Opal�s heavy water was completed during the reactor�s last shut-down.

�Returning to power with new heavy water is not only a major step towards recommencing full nuclear medicine production, but allows irradiation of silicon for the semiconductor industry. It will also permit assessment of the full performance of Opal,� ANSTO said.

The heavy water in Opal�s reflector vessel was replaced because over the past two years, normal water from the surrounding reactor pool had slowly seeped in and diluted it, ANSTO said. Although not a safety issue and one that does not prevent operation of the reactor, dilution reduces neutron intensity, which can affect the ability to irradiate targets for radiopharmaceutical production and silicon irradiation.

The water seepage was first identified in 2006. During a 10-month shutdown in 2007-08, to repair an unrelated fuel design fault, ANSTO and Argentine designers INVAP started investigating ways to permanently fix the seepage points. This investigation is still ongoing.

On 4 November, the IAEA highlighted recent problems in Europe when simultaneous outages of three medical isotope production facilities led to a global shortage of technetium 99m.

The IAEA said it is trying to ease potential problems 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. The 70-page document is available in pdf format on the agency�s web site (http://www-pub.iaea.org).

� by John Shepherd

>>Related reports in the NucNet database (available to subscribers)

ANSTO Restructuring Will �Re-focus Priorities� And Cut Staff (News in Brief No. 56, 19 May 2008)

Petten High-Flux Reactor Scheduled To Restart In February 2009 (News No. 77, 15 October 2008)

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