The High Flux Australian Reactor (HIFAR) was Australia's first nuclear research reactor. It was built at the Australian Atomic Energy Commission (AAEC) research establishment at Lucas Heights, Sydney, New South Wales. The reactor was in operation between 1958 and 2007, when it was decommissioned and replaced with the multi-purpose Open-pool Australian lightwater reactor (OPAL), also in Lucas Heights. Both HIFAR and its successor OPAL have been known simply as the Lucas Heights reactor.