HistoryThe Argentine company INVAP S.E. was the main contractor responsible for the delivery of the reactor, performing the design, construction and commissioning. The facility is currently in the final stages of commissioning. OPAL was opened on April 20, 2007 by Prime Minister John Howard12 and is the replacement for the HIFAR reactor. ANSTO received an operating license from the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) in July 2006, allowing commencement of hot commissioning, where fuel is first loaded into the reactor core. OPAL went critical for the first time on 13 August 2006 and reached full power on November 3, 2006. 3 Facility detailsThe reactor core consists of 16 low enriched plate type fuel assemblies and is located under 10 metres of water in an open pool. Light water (normal H2O) is used as the coolant and moderator while heavy water (D2O) is used as the neutron reflector. OPAL is expected to become the centrepiece of the facilities at ANSTO, providing more efficient and rapid radiopharmaceutical and radioisotope production, irradiation services (including neutron transmutation doping of silicon), neutron activation analysis and neutron beam research, outperforming the current ANSTO reactor in every aspect. OPAL will be able to produce four times as many radioisotopes for nuclear medicine treatments, and a wider array of radioisotopes for the treatment of disease. The design includes a cold neutron source (CNS) allowing research not possible at the existing facility. The OPAL reactor already has received seven awards in Australia 4 Neutron scattering at OPALThe Bragg Institute at ANSTO hosts OPAL's neutron scattering facility and comprises the following instruments:
Shutdown due to loose fuel platesFollowing the discovery of loose fuel plates during a routine inspection, the ANSTO announced on July 27, 2007 that the reactor would be shut down for 8 weeks to fix the fuel plates and a minor fault causing light water to seep into the reactor's heavy water.56 According to reports, during the examinations no radiation leakages were detected, although it took much longer than 8 weeks to obtain the necessary clearances to complete repairs and readjustments. ANSTO announced on 25 October 2007 that the reactor would remain shut down until early 2008 while it sought approval from ARPANSA to restart the reactor.78 As of March 2008, the reactor remains shut down. According to an ANSTO news release on 22 February 2008, "Late last week, ARPANSA submitted a series of questions on the application, which ANSTO will respond to as quickly as possible. This is expected to take some weeks."9 The supply of radiopharmaceuticals has been rationed, causing the postponement of some treatments for patients; this is causing some concern amongst doctors in nuclear medicine.10 The OPAL nuclear research reactor returned to full operational power on 23 May 2008 after a 10 month shutdown following approval by the nuclear regulator, ARPANSA to use a modified fuel design.11 See alsoReferences
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