Industrial activity at uranium mines, nuclear power plants, research, and medical facilities creates radioactive waste, which is essentially any post-production solid, liquid or gas that contains substances that emit radiation. While a certain amount of radioactive waste is inevitable, the actual volume of waste is relatively low, while responsible management can bring any associated risks down to acceptable levels.
There are essentially three types of radioactive waste from nuclear reactors and industrial processes:
The methods required to safeguard radioactive waste depend on the type. Low-level waste presents such a low risk that it can be safely handled, whereas intermediate-level waste is usually stored in steel-lined concrete containers. High-level waste requires more rigorous procedures.
Naturally, the uranium used in the nuclear industry is mined from rock, not all of which contains enough uranium ore to process economically. This means that some trace levels of uranium are brought out of mines but not processed. Uranium ore must also be milled, and every milling process creates tailings, which also contain trace amounts of uranium.
These trace amounts are in such low concentrations that they are not economical to process; they also represent a very low exposure risk. So, the waste rock is usually stored above ground, close to the mine, with appropriate precautions to protect people and the environment. Mill tailings are permanently stored in carefully designed and constructed facilities, usually within a few kilometers of the mill. These permanent storage facilities, known as “tailings impoundment areas” may be contained behind engineered dams or in natural depressions.
Canada developed its rigorous controls for managing radioactive waste over many decades – and some early nuclear operations took place before these controls were fully in place. One result of these operations is uranium and radium soil contamination at several sites in the Northwest Territories, British Colombia, Alberta, and Ontario. Some of this contamination resulted from industrial processes, such as the production of radioluminescent dials in Toronto, refining operations in Port Hope and Clarington, Ontario, or transportation of ore through docks and boat launches in the Northwest Territories.
In cases where the original owner could not be held to account, the Government of Canada has taken on responsibility for ensuring the remediation of the sites. Remediation involves bringing the risk of human or environmental radiation exposure down to acceptable levels, and usually follows consultations with any communities that might be affected. Remediation processes depend on the type of waste, the risks it poses, and the local environment, and may include covering of contaminated soil, containment of waste products, or transportation of waste to lower-risk areas.