The recent successful return to operation of ANSTO’s OPAL research reactor in May has seen preparations for neutron research and commercial irradiation progressing well.
Commercial production of molybdenum is expected in fourth quarter 2008 and commissioning of new neutron instruments is nearly complete.
One outstanding issue is the previously identified problem of heavy water dilution due to normal water seeping into the heavy water vessel.
The water seepage was first identified in 2006 and an attempt was made during the recent extended shutdown to address the problem using a novel method of injection of microscopic alumina particles into the affected areas.
This solution does not appear to have been successful and ANSTO is now examining several other remedies with the reactor designer INVAP.
Prior to the shutdown, several cups a day of light or normal water were seeping into the heavy water vessel which surrounds the reactor core from the reactor pool. The heavy water is designed to reflect neutrons back into the core, to sustain the nuclear reaction and provide high quality neutrons for research.
The seepage is not a safety issue and does not prevent operation however ANSTO has advised the safety regulator. The problem needs to be addressed because the slow reduction in heavy water purity reduces reactor efficiency and performance.
This week, whilst the reactor is undergoing its monthly fuel exchange shutdown, tests are taking place to establish the extent of the water seepage. OPAL will return to full operation once tests are completed.
With the reactor operating the seven new neutron instruments are expected to progressively come on line for researchers. It is expected that export of irradiated silicon for the electronics semiconductor industry will resume in late July.
Commercial supply of the primary radiopharmaceutical, technetium-99 which is made using reactor-produced molybdenum will commence later this year when regulatory approvals are obtained.
Published: 08/07/2008