OPAL

The Open Pool Australian Lightwater reactor replaced the 1958 HIFAR at Lucas Heights, south of Sydney. ANSTO contracted it from INVAP in June 2000 under a turnkey contract; it went critical for the first time on August 12, 2006 and was opened on April 20, 2007. It is the largest research reactor Argentina has ever exported and the design reference for those that followed, the RA-10 and Brazil's multipurpose reactor.

The core is compact: 16 plate-type low-enriched uranium fuel assemblies in a 4 × 4 array, with five control rods, under 13 meters of light water in an open pool. Around it, a heavy-water tank acts as reflector and houses the irradiation positions, a liquid-deuterium cold source and the beam tubes that feed the Australian Centre for Neutron Scattering. It runs in 30- to 35-day cycles, scheduled for 300 days a year; in 2025-2026 it operated 98.3% of the scheduled time. It produces molybdenum-99 for a quarter of the world market, with capacity for half, and dopes silicon by neutron transmutation for the semiconductor industry: over 10 million nuclear medicine doses and 900 tonnes of silicon in its first twenty years.