Methods of disposal

Disposal of radiation equipment

Final disposal of any irradiating apparatus or electronic product must be carried out by a licenced service person in accordance with the methods below:

  • X-ray equipment – at minimum the x-ray tube must be disabled, by eliminating the vacuum inside the x-ray tube by physically breaking the glass envelope, and the high-tension cables must be severed, to render the equipment inoperable. It would also be preferable to remove the circuit board controlling the high voltage generator where possible.
  • Lasers – removing the power supply (by severing the cord) and removing the critical optical components and the amplifying medium to render the equipment inoperable.
  • Transilluminators – removing the power supply (by severing the cord) and removing the UV lights from the unit and destroying them will render the equipment inoperable.

Disposal of liquid radioactive waste (water soluble)

Liquid radioactive waste is best disposed of via the sewer system. Such waste must only be disposed of via flushing sinks connected to approved radioactive drains provided for this purpose.

Ensure that the activity per flush is below the legal dilution concentration limit for each radionuclide and that the waste complies with the Water Corporation’s ‘Acceptance criteria for trade waste’.

Disposal of solid or liquid (non-soluble) radioactive waste

Segregation

Waste must be segregated according to the radionuclide and the type of waste. For example:

  • Biological material (e.g. food, animal carcasses)
  • Sharps (e.g. syringes, broken glass)
  • Scintillation cocktail from counting tubes
  • General laboratory waste (e.g. gloves, paper towels)

Long-lived radionuclides must not exceed the activity box limits as outlined in the following table.

Long-lived RadionuclideBox Limit 
MBqmCi
3H481300
14C3.492
36Cl2.259

Packaging

Solid waste must be sealed in a red plastic bag. Other liquid waste must be sealed in a screw top bottle or vial before being sealed in a red plastic bag. Any sharps, such as needles or broken glass, must be enclosed in a hard container (metal tin or plastic sharps container).

The red plastic bag or hard container must be placed in a cardboard box or multi-walled paper bag with the words ‘Radioactive material’ printed clearly on the outside.

The box or bag must then be sealed with tape that is suitable for storage (50 mm wide masking tape is commonly used).

Labelling

Label the waste box or bag with the type of waste it contains together with a contact name and location of where the waste comes from.

Write the radionuclide and provide an estimate of total activity. Only use units of activity (Bq, Ci and their derivatives). Do not use other units such as counts per second or Bq per mL.

Transportation

Confirm whether the activity of the waste is low enough to be transported as an ‘excepted package’.

Liaise with the University Radiation Safety Officer to arrange a time for delivery to the University radiation waste store and transport the waste at the designated time.

Ensure the waste is handed directly to staff at the store. Do not leave radioactive waste unattended at any time.