On October 6, 2023 Regulations Amending the Transportation of Dangerous Goods Regulations (Site Registration Requirements) were published the the Canada Gazette, Part II, which means they are now in effect. If you import, offer for transport, handle, or transport dangerous goods in Canada, including but not limited to Class 7 Radioactive Material, you more than likely have to register with the CID. See https://tc.canada.ca/en/dangerous-goods/client-identification-database-cid for information to help you know whether or not you need to register. There is a 12-month grace period from the time the Regulations came into force to be compliant.
Corresponding with Transport Canada, there are cases where you may not need to register. For example, if all you ship is Class 7 excepted packages as defined by Section 1.43 in the TDG Regulations, you do not need to register because they are exempt from Section 17 of the Regulations. We also confirmed that if the CNSC’s Packaging and Transport of Nuclear Substances Regulations do not apply to any and all of your shipments due to the exceptions listed in Section 2, then you do not need to register. We provide this information for awareness purposes, it is not legal advice, and you will need to confirm your need to register based on your scenario.