What is radioactive waste?

Radioactive waste is material that has no foreseeable use and contains radioactive materials with activities or activity concentrations at levels where regulatory oversight is needed to ensure safety. In Australia radioactive waste is generated in a variety of medical, industrial, research and agricultural practices.

All radioactive materials (or radionuclides) have a half-life (the time it takes for half of the radioactive atoms to decay). This means that the radioactivity of all radioactive waste gets lower over time. For this reason not all types of radioactive waste should be managed in the same way. For example, radionuclides with a short half-life can be stored until they are safe to dispose of as normal waste. Longer lived radionuclides (like uranium) will remain radioactive for millions of years.

Waste classification

The Australian classification scheme for disposal of radioactive waste is based on the safety of disposal pathways, taking into account the radioactivity level and the time it will take for the radioactivity to decay (half-life). Radioactive waste classification within Australia currently includes:

Exempt Waste (EW)
  • Contains very low levels of radioactivity where safety measures are not required.
  • Can be safely disposed of in the same way as non-radioactive waste.

Very Short Lived Waste (VSLW)
  • Contains very short lived radioactivity.
  • Can be safely stored for short time periods and then disposed of the same way as non-radioactive waste.

Very Low Level Waste (VLLW)
  • Contains low levels of short lived radioactivity.
  • Can be safely disposed of in existing industrial or commercial landfill-type facilities with limited regulatory control.

Low Level Waste (LLW)
  • Contains higher levels of short lived radioactivity and low levels of long lived radioactivity.
  • Can be safely disposed of in an engineered near-surface (3-10 metres) facility.

Intermediate Level Waste (ILW)
  • Contains higher levels of long lived radioactivity.
  • Can be safely disposed of at greater depths (up to a few hundred metres).

High Level Waste (HLW)
  • Contains levels of radioactivity high enough to generate significant amounts of heat during the radioactive decay process.
  • Disposal in deep, stable geological formations (several hundred metres below the surface) is recognised as the safest disposal pathway.

Management of radioactive waste

Australia’s commitment

Australia is a Contracting Party to the Joint Convention on the Safety of Spent Fuel Management and the Safety of Radioactive Waste Management. This requires Australia to establish and maintain a legislative and regulatory framework to govern the safety of spent fuel and radioactive waste management, and to protect people and the environment against radiological hazards from these materials.

Management practices

There are a range of strategies for managing radioactive waste. These depend on a variety of factors including the level of radioactivity in the waste, the half-life, physical properties (solid, liquid, gas), chemical properties, toxicity, and economic and social factors. In Australia, current management practices include:

Treatment and conditioning:

  • The purpose of treatment and conditioning is to convert waste into a safer and more manageable form.
  • Treatment of radioactive waste may involve segregation, chemical adjustment, decontamination, containment, volume reduction and change of composition.
  • Conditioning may involve converting the waste into a more manageable form or enclosing waste into containers.

Storage:

  • Radioactive waste needs to be stored safely and securely until it can be disposed of permanently. Most radioactive waste in Australia is currently in storage at a number of sites around the country. Storage is an ‘interim’ measure before suitable disposal pathways can be developed.
  • In some cases, such as very short lived waste, temporary storage allows for the radioactivity to decay to a level where the material is no longer a radiological hazard to people and the environment.

Disposal:

  • Permanent disposal is considered internationally to be the safest long-term management option for radioactive waste.
  • Disposal options vary depending on the classification of the waste (i.e. the radiological hazard) and the properties of the waste. Options include disposal to sewers, the atmosphere, landfills, and specially engineered facilities. Any disposal of radioactive waste must be approved by the relevant regulator.

Frequently asked questions

More of your questions on radioactive waste safety in Australia are answered on our frequently asked questions page.

 

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