SYDNEY (AFP) - A fire broke out at a nuclear research reactor in Sydney Tuesday, but authorities said the blaze was brought under control and there appeared to be no damage to the reactors. The fire broke out as the city sweltered through a heatwave which has triggered dozens of bushfires, but the Australian Nuclear Science and Technology Organisation (ANSTO) said the incident was not linked to the weather conditions. The state fire service said smoke was detected in an electrical substation at the rear of the Lucas Heights nuclear facility in southern Sydney shortly after 10.30am (2330 GMT Monday) but the source was yet to be found.