The Australian Nuclear Science and Technology Organisation today welcomed the conclusion of Dr John Loy, the Chief Executive of Australias independent nuclear regulator, the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA), that the presence of the geological fault at the site of the replacement research reactor (RRR) does not alter the seismic design basis on which the construction licence was issued. Therefore construction at the site can proceed.
ARPANSA subjected the results of expert geological studies, undertaken for ANSTO, to independent review by Geoscience Australia and by an international expert in seismic analysis nominated by the International Atomic Energy Agency. These independent reviews have supported the conclusions of ANSTOs studies that the site is geologically stable.
ARPANSA first issued a licence to construct the reactor on 4 April 2002. In June 2002, ANSTOs ongoing and detailed geological mapping of the replacement research reactor site at Lucas Heights site led to the identification of faults in rocks exposed by the foundation excavation at the RRR site.
Subsequently two main fault strands in the bedrock exposures were identified and detailed analysis of these conducted.
These subsequent studies were reviewed by reputed national and international experts.
According to ANSTO Chief Executive Officer, Professor Helen Garnett, "That analysis which took some three months involved a detailed analysis of the fault and the use of a number of sophisticated techniques to date the age of its last movement.
"It demonstrated conclusively that the absolute minimum age of last movement of the fault is five million years, and probably significantly older", she said. Faults like this are found all over the Sydney basin including under NSW Parliament House, recently constructed residential buildings between Circular Quay and the Opera House, a number of buildings at Darling Harbour, Warragamba Dam, Redfern and Central stations, Woolloomoloo viaduct piers and all the sewage outfalls.
According to international criteria, such ancient faults are not considered as being of any significance for the siting of considerably larger power reactors, let alone research reactors.