Measures to detect radioactive sources
These accidents show that it is important to be aware of the potential hazards from radioactive materials and recognize materials that may be radioactive. Smaller companies and independent scrap dealers are particularly at risk, if they do not have proper detection systems and procedures in place to check the origin of the scrap and if their workers are not trained to recognize international symbols. Those working with scrap metal should be aware of the labelling used to indicate the presence of radiation.
High activity sealed radioactive sources are usually in heavy containers because of the density of metals used to shield their radioactivity. Heavy metal containers (lead, tungsten or depleted uranium) are used to block the gamma rays. This shielding is used to protect those who work with sources and by-standers during transport.
The trefoil is the official international radiation symbol used to label sources, containers, or devices. In addition to the trefoil symbol, the word radioactive may also appear. Some containers used for transporting sources will have other information on the amount of radioactivity or the type of protective container. Some sources, such as fine needles used for killing tumours, are too small to have any symbols. However, their containers will labelled. The display of printed material (e.g., posters) that show typical devices containing the sealed sources at the premises will provide a constant reminder for the staff of their potential risk.
Several countries have set up monitoring equipment at ports of entry to detect undeclared radioactive materials before they enter the country. Many large scrap yards and foundries also use radiation detectors to check loads of incoming scrap for signs of radioactivity. Improved record keeping on the origins of scrap metal may also help reduce the risk of undetected radioactive materials.
In addition to the exposure risks, melting down a radioactive source can contaminate equipment, requiring very costly clean-up, long-term waste management, and interruption of business. It is in the best interest of operators at foundries and steel factories to have procedures in place to detect radioactive material.
If radioactive material is found or suspected, the staff need to know what to do and who to contact. Operators should develop procedures to follow and make sure they are understood by workers. Emergency numbers for relevant agencies should be posted and updated regularly.
All staff responsible for collecting, transporting and processing scrap metal should be provided with on-going training on the procedures in place to monitor for radiation and check for radioactive materials. Training should include how to recognize radiation symbols.