Drew Rooke
Nestled amongst bushland just above the Woronora River in the southern Sydney suburb of Lucas Heights lies Australia’s only nuclear science campus.
The scientific campus is made up of three key facilities and is run by the Australian Nuclear Science and Technology Organisation (ANSTO). Since it started operating more than fifty years ago, it has undergone many upgrades and improvements – and, according to a line deep in the 2023–2024 federal budget, it is bound for even more that will help “[secure] a responsive nuclear medicine and science capability for Australia.”
It may also be expanded.
The centrepiece of the Lucas Heights nuclear site is the 20-megawatt Open Pool Australian Lightwater nuclear reactor – otherwise known as OPAL.
This reactor is the successor of the 10-megawatt High Flux Australian Reactor (HIFAR). The first nuclear reactor in use at Lucas Heights – and the first to be built in the southern hemisphere – HIFAR was opened in 1958 and was housed in a sealed circular steel building 21 metres wide and 21 metres high. Its core contained 25 fuel rods and 280 grams of uranium enriched with U235
Based on the DIDO reactor at Harwell in the United Kingdom, the reactor was originally intended to test materials for use in future nuclear power reactors. But its purpose changed with the decision not to pursue a nuclear power program in Australia: it became a research reactor, producing radioisotopes for medicine, agriculture, industry and research.
In simple terms, radioisotopes are radioactive isotopes. The gamma rays they emit is traceable, allowing experts to precisely observe their movement in a subject using specialist imaging technology which detects small amounts of radiation.
In January 2007, following nearly 50 years of operation, HIFAR was shut down. Four months later, the $300 million OPAL reactor was officially opened by then prime minister John Howard.
OPAL is estimated to have a 60-plus years design life. It is currently one of 222 operational nuclear research reactors in 54 countries around the world, according to the International Atomic Energy Agency research reactor database.
A further 23 research reactors in 16 countries are either planned or under construction; 79 reactors in 30 countries are in either temporary, extended or permanent shutdown; and 517 are under decommissioning or have been decommissioned.
Housed inside a concrete-reinforced building that is designed to withstand the impact of a one in ten-thousand-year earthquake, OPAL is the only nuclear reactor in Australia – and one of the few research reactors in the world capable of producing commercial quantities of radioisotopes that are used for a range of medical purposes. It generally runs for 30 days non-stop at full power, followed by a stop of five days to reshuffle the fuel.
It is inside these containers that Mo-99 transforms into Tc-99m, which is used to diagnose heart disease, cancer and a range of other illnesses, and to study organ structure and function.
The reactor core – 35 centimetres square and 60 centimetres high – comprises 16 low-enriched uranium silicide fuel plates with aluminium cladding and is submerged near the bottom of a 12.8-metre-deep pool of demineralised, turquoise-coloured water.
ANSTO’s website says OPAL is a research reactor. “It generates roughly 20 Megawatts of heat using around 30kg of uranium. This is very small when compared to a typical nuclear power reactor, which may operate at a thermal output of around 3000 Megawatts to generate 1000 Megawatts of electricity and contain around 100,000 kilograms (kg) of uranium.”
Radioisotopes are produced by the reactor through the process of fission, by which a neutron slams into the nuclear of a uranium atom and splits it, releasing a large amount of energy and heat that is cooled by the water circulating between the fuel plates.
Among the radioisotopes produced is molybdenum-99 (Mo-99) – the precursor to the most widely used radioisotope in nuclear medicine, technetium-99m (Tc-99m). The irradiated target plates that contain this critical radioisotope are then sent to the nearby and newly constructed Mo-99 Manufacturing facility – ‘Building 88’ – where they are dissolved in shielded hot cells.
Once the Mo-99 has been extracted and purified in ‘Building 88’, it is then transported to ANSTO’s nuclear medicine and distribution facility – ‘Building 23’ – which opened in 1958. It is then dispensed into specially designed white and yellow containers called “Gentech Generators” which are sent to medical facilities around the country.
It is inside these containers that Mo-99 transforms into Tc-99m, which is used to diagnose heart disease, cancer and a range of other illnesses, and to study organ structure and function.
According to ANSTO, about 75-80 percent of nuclear medicine isotopes used in Australia come from Lucas Heights. One full Mo-99 production cycle at the campus produces about 40 millilitres of the radioisotope – enough for approximately 10,000 patient doses.
“It’s absolutely critical to have a domestic supply of Mo-99”, says Dale Bailey, a physicist working in the field of nuclear medicine at Royal North Shore Hospital and a professor and lecturer at the University of Sydney.
“We really learnt that during the pandemic when there were disruptions to international supply chains.”
But producing radioisotopes that are critical for human healthcare isn’t the only function of the OPAL reactor; it also produces irradiated silicon through a process known as Neutron Transmutation Doping. This is also critical to our modern day lives, as irradiated silicon has an enhanced ability to conduct electricity and is essential for products like high-powered computer chips.
Each year, ANSTO irradiates more than 50 tonnes of silicon, which is used by the electronics industry across Europe and Asia.
It appears the much-needed money for upgrading the Lucas Heights nuclear campus might finally be forthcoming.
In recent years, the Lucas Heights nuclear campus has been dogged by safety concerns and shutdowns.
In August 2017, for example, a technician working in ‘Building 23’ dropped a vial containing radioactive material. His hands were contaminated through two pairs of gloves, exposing him to an elevated risk of cancer. According to the International Nuclear Event Scale – the global grading system for nuclear incidents – the event was deemed the most serious in the world in 2017.
Within the next ten months, there were three other less-serious incidents, and in October 2018, an independent report was published which found the precinct failed to meet modern nuclear safety standards and had a culture of “make do and mend.”
Then, in June the following year, there was a mechanical failure at ‘Building 23’ that led to a major disruption of domestic supply of Mo-99. Four months later, “we are still experiencing the impact on daily activity in our hospitals and practices of this point failure on the production line,” as Bailey wrote at the time in a special report for the official newsletter of the Australian and New Zealand Society of Nuclear Medicine.
According to the independent report from 2018, a major cause of the ongoing problems at Lucas Heights has been federal government budget restrictions that have hindered longstanding plans to decommission and replace the ageing Building 23. “The lack of a permanent replacement solution … is undermining the possibility of truly effective risk control,” the report found.
But it appears the much-needed money for upgrading the Lucas Heights nuclear campus might finally be forthcoming.
In the most recent federal budget, the Commonwealth government announced “funding over 10 years from 2023–24 to construct a new nuclear medicine manufacturing building, as well as ongoing maintenance of the current ageing facility.” This will enable Australia to continue supplying the domestic market – and increase its supply for the international market. Indeed, according to ANSTO, “world demand for Mo-99 is large and growing, as more countries develop modern medical systems.”
The Federal government also announced “funding over two years from 2023–24 for ANSTO to develop a business case for a new facility supporting Australia’s sovereign nuclear security science capability” – one that would be “different to the nuclear medicine manufacturing facility,” according to an ANSTO spokesperson.
The ANSTO spokesperson did not provide detail about either announcement and the budget did not disclose exactly how much funding has been allocated, owing to “commercial sensitivities.”
However, Bailey understands that the funding is to build a full replacement of ‘Building 23’ which will be “a highly automated, state of the art facility with about a fifty-year lifespan” – similar to SHINE Technologies’ large-scale Mo-99 manufacturing facility in Janesville, Wisconsin, that is soon to be operational.
Bailey believes the cost could be twice the $210 million that, in 2019, was estimated was needed to refurbish the facility.
But whatever the cost, Bailey is adamant it will be worth it to secure a domestic supply of nuclear medicine in Australia.
“It’s something we need to do,” he says. “And it is a long-term investment.”