- This procedure applies to all refrigerators, freezers, animal cages, and other equipment, which have contained radioactive materials or were used for radioisotope research.
- If contamination with biological or chemical hazardous materials is possible, be sure to follow all appropriate precautions for each type of hazard.
2. Safety Precautions
- Wear your lab coat, double gloves and goggles. If a gamma/x-ray or strong beta energy emitting radionuclide was used/stored, be sure to wear whole body and ring TLDs.
- Be prepared to collect the excess water used for cleaning by putting trays or paper towels under the equipment.
- Dispose of all cleaning materials as radioactive waste.
- Remove your gloves and lab coat at the end of the work.
- Wash your hands before leaving the laboratory.
3. Preliminary Preparations
- Remove all loose materials from the equipment. If the materials are for disposal be sure to follow the appropriate disposal procedure for each type of material (non-hazardous, hazardous: radioactive, chemical, biological).
- Clean the equipment using water and a mild detergent. Collect the water and check it for contamination. To do so, put 0.5 mL of water in a scintillation vial, add 5 mL of scintillation fluid and measure the vial using a LSC (be sure to use the appropriate LSC window depending on the radionuclide used/stored in the equipment)
- If the water used for cleaning is contaminated (having radiation levels above background) dispose of the water as liquid radioactive waste. Be sure to use the appropriate liquid waste container depending on the half-life of the radionuclide used/stored in the equipment. Repeat step 2.
- If the water used for cleaning is not contaminated, dispose of it to the drain.
- If after washing using water and mild detergent, the measurement still indicates a level of radioactive contamination above the criteria (see “Equipment Radiation Monitoring Contamination Criteria”), proceed with more aggressive decontamination. To do so:
- You can use physical agents such as brushes or abrasive materials. Press hard on the contaminated surface using a circular motion. Start from the outside of the contaminated area and work towards the middle to prevent spreading the contamination.
- You may require chemical agents (decontamination solutions or ion exchange agents).
- After using chemical or physical agents, wash again with clean water, allow the surface to dry and measure the contamination (see “Procedure for Equipment Radiation Monitoring”)
- If the surface is still contaminated, the contamination will be considered fixed. In this case contact the Radiation Protection Service. A RSO will measure the level of the radiation field and make recommendations for the future use or disposal of the equipment.
5. Notification and Record Keeping
If the equipment will be removed form a radiation permitted area for reuse in non-radioactive applications or for disposal, remove all radiation signs, and inform the U of T Radiation Protection Service. A RSO will visit the lab, audit the decontamination process, check the contamination, and write an equipment decommissioning report. A copy of the report will be placed on the equipment. The moving personnel will not touch the equipment if they do not see the decommissioning report signed by an RSO.
The results of all measurements should be kept for three years.