The design of the OPAL builing is modern and clean and a warm welcoming environment for workers and visitors. OPAL's building design incorporates first class security features, safety, efficiency and concern for the surrounding environment.

The OPAL reactor facility has three parts: 1. OPAL reactor core and reflector vessel, 2. Cold-neutron source and 3. Neutron guides and scientific instruments.

Eight neutron beam instruments are planned for the OPAL reactor. The facility has the capacity for further expansion, including potential for a second neutron guide hall.

On 20 April Prime Minister of Australia, Mr John Howard officially opened the OPAL reactor at ANSTO.

The Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) issued a licence to construct the reactor on 5 April 2002. An operating licence was issued on 14 July 2006 and OPAL first went critical at 11.25pm on 12 August 2006.