ANSTO HIFAR.

HIFAR was one of six DIDO-class reactors built worldwide, a heavy-water-moderated 10 MW design. The reactor block was a right irregular decagonal prism of iron-shot concrete, steel-clad, 6.7 metres across the flats, sitting behind the white containment dome that became the visible landmark of the Lucas Heights skyline. Head Wrightson of Stockton-on-Tees built it under contract from 1955, with Stephenson and Turner of Sydney as consulting architects.

HIFAR was built to support a civil nuclear power programme that Australia never adopted. What kept it running for half a century instead was nuclear medicine and semiconductor production. The reactor produced technetium-99m generators shipped to 11 Asia-Pacific countries, and from around 1985 it irradiated high-purity silicon for the global semiconductor industry.

HIFAR shut down at 10:25 am on 30 January 2007, 49 years and 4 days after first criticality, the last of the six DIDO-class reactors worldwide to go cold. OPAL, a 20 MW open-pool reactor built by INVAP in Argentina, had reached full power on the same site three months earlier. Engineering Heritage Australia listed HIFAR as a National Engineering Landmark in 2001, and the containment shell is retained while Phase A decommissioning proceeds.