What is radioactive waste?
Radioactive waste contains radioactive elements that send out higher levels of radiation than natural background radiation.
Radioactive waste can be classified into three main categories - low, intermediate and high.
Low-level waste emits radiation at levels which generally require minimal shielding during handling, transport and storage.
Ninety-two per cent of the radioactive waste produced by ANSTO is low-level waste, made up of paper, plastic, gloves, cloths and filters which contain small amounts of radioactivity.
This waste is shredded and compressed into 200 litre drums, which are safely stored on-site. The radioactivity is measured using a scanning system.
The drums are bar-coded and the radioactive content of each drum is entered into a database to ensure that the waste is safely, securely and efficiently managed in compliance with the standards set by the International Atomic Energy Agency (IAEA) and the Australian regulator – the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA).
Intermediate-level waste emits higher levels of radiation and requires additional shielding during handling, transport and storage.
A contact dose rate of 2 millisieverts per hour and above is used to distinguish between low and intermediate waste. Intermediate-level waste at ANSTO is generated from radiopharmaceutical production and reactor operations. Approximately 3.5 cubic metres of solid intermediate-level waste is generated each year.
High-level waste has higher levels of radiation which requires increased shielding and isolation from human contact and requires cooling due to its heat-generating capacity. It is produced from the operation of nuclear power plants. No high-level waste is produced at ANSTO.
Radioactivity gradually diminishes as the radioactive elements decay into more stable elements, so waste gradually becomes less radioactive and safer to handle over time.
The period of time required for radioactive elements to decay is dependent on the half-life of the radioactive element – also known as the nuclide or isotope.