The storage solutions for radioactive waste depend on the type of waste involved, and the risk it represents.
Low-level waste is typically stored onsite, until its radiation level has decayed to the point that it can be disposed of as ordinary garbage; if longer-term management is required, it is sent to an appropriate waste-management facility. The facilities that produce the low-level waste are licensed by the Canadian government to safely handle, store, and dispose of these wastes.
Intermediate-level waste items have a high enough level of radioactivity to require shielding during interim storage – in lead containers, for example – to protect people who work nearby. This waste is stored onsite, or safely transported to another site that is licensed for long-term storage.
Storage of high-level waste is a more complex operation. Used fuel bundles are stored in cooling pools at the nuclear power plant for 5 to 10 years until they cool. They are then placed in large dry concrete and steel containers, with several layers that are thick enough to contain the radiation and cause no harm to workers or the surrounding environment. Until a permanent disposal repository for used nuclear fuel is built, nuclear power plant operators must safely store this fuel under license at their plant sites in these containers. The Canadian Nuclear Safety Commission website provides more detailed information on the types of storage and the features of storage canisters for high-level waste.