OPAL news
As most of our users are aware, the last 3 months have been difficult: on 24 July 2007, the OPAL reactor was shut down following a fault with some of the reactor fuel assemblies, some of which had one or more fuel plates displaced vertically. All the fuel assemblies have now been unloaded from the reactor core and are stored safely in the service pool.
INVAP (the reactor designer) and ANSTO are undertaking investigations and tests using dummy fuel assemblies in the reactor and in flow-test facilities to investigate potential causes for the fault. In addition, INVAP in consultation with the fuel manufacturer (CNEA) is working on potential design changes aimed at stopping the displacement of fuel plates from the assemblies. Restart of the reactor will depend upon approval of our regulator ARPANSA, who is being continuously informed of progress.
During this shut-down period, repairs to the reflector vessel defects (seepage of light water into heavy water) are being carried out. The first results of the repair programme are satisfactory, and completion is expected by the 3rd week of October. The schedule for reactor restart will then become clearer: at present the best estimate is some time between November and early in 2008.