The article focuses on the Open Pool Australian Lightwater (OPAL) reactor, a mixed-use research reactor responsible for the supply of reactor-based isotopes globally, particularly Mo-99/Tc-99m that are considered as the workhorse of nuclear medicine. It explores the irradiation operation of the OPAL reactor at high power for 300 days which compares with the highest performing mixed-use reactors. OPAL reactor was opened by the Australian Nuclear Science and Technology Organisation (ANSTO).