It is relevant to recognise that initial medical treatments were based on the use of Radium( Ra-226), creating the need for long term waste management due to the half-life of approximately 1,600 years. Medical practice moved to using shorter half-life isotopes( Iodine-131, Technetium-99m, Iridium-192 etc.) that are more easily managed from a waste perspective. However, the next wave of medical treatment is turning back to radionuclides as part of long decay series where production involves longer half-life parent isotopes( e. g. Thorium-229, Thorium- 228, Actinium-227), which have an associated need for longer term waste management; highlighting some of the challenges.
A key characteristic of radioactive waste is that it covers such a broad and diverse range of material, from smaller volumes of higher activity concentration materials, to the large volumes of very low activity concentration material. In Australia, with its emphasis on raw resources, mine tailings from uranium, mineral sands, rare earths and some base metal tailings, special focus is required to ensure their long-term safe storage and disposal.
Mine tailings are the waste materials from mining and processing. They usually contain the majority of radionuclides and other contaminants and can pose significant environmental risks requiring careful management.
When assessing radioactive waste, it is also important to consider its other potentially hazardous properties. This is particularly the case for mine tailings which might be classified as radioactive but can also be acidic and contain other heavy metals. Disposal facilities therefore need to consider the range of hazards and risks that exist, including designing to mitigate failure scenarios into the future.
As Australia explores the use of nuclear power for defence purposes, and new
Iodine store and decay facility
medical treatments become available, the need for a national waste repository continues to grow. The Australian Government has established the Australian Radioactive Waste Agency( ARWA) to progress this work to select and develop a national repository for radioactive waste. ARWA also manages the sharing of old medical Ra-226 between holders and users for the production of new medical isotopes.
From a radiation protection practitioner’ s perspective, there are many challenges with management of radioactive waste from its classification, then transport, to final disposal options. While the large volume NORM waste streams from mining are generally managed separately, the key challenge in Australia is the lack of a national repository for other waste streams. As practitioners, we see this as a national priority.
Plutonium powered heart pacemaker – still radioactive long after the owner passed away- correction fluid included for scale.
14 Radiation Protection Today www. srp-rpt. uk