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Overview of radioactive waste in Canada

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What is radioactive waste?

Radioactive waste is defined as any material (liquid, gaseous, or solid) that contains a radioactive substance, for which no further use is foreseen. Radioactive waste also includes nuclear fuel waste, as defined in section 2 of the Nuclear Fuel Waste Act, and radioactive waste generated as a result of a nuclear or radiological emergency.  More information on Canada’s radioactive waste can be found in the Inventory Report.

Radioactive waste should be classified according to the degree of containment and isolation that is necessary to ensure safety, with additional consideration given to the hazardous potential of different classes of waste and the time frame associated with the hazard. In Canada, there are four general classes of radioactive waste.

High-level radioactive waste

High-level radioactive waste is waste with levels of activity concentration high enough to generate significant quantities of heat by the radioactive decay process or waste with large amounts of long-lived radionuclides that need to be considered in the design of a disposal facility for such waste. High-level radioactive waste is associated with penetrating radiation, and thus shielding is required. High-level radioactive waste also contains significant quantities of long-lived radionuclides necessitating long-term isolation. Placement in deep, stable geological formations is recommended for the long-term management of high-level radioactive waste.

Intermediate-level radioactive waste

Intermediate-level radioactive waste generally contains long-lived radionuclides in concentrations that require isolation and containment for periods greater than several hundred years. Intermediate-level radioactive waste needs no provision, or only limited provision, for heat dissipation during its storage and disposal. Due to its long-lived radionuclides, intermediate-level radioactive waste generally requires a higher level of containment and isolation than can be provided in near surface repositories. 

Low-level radioactive waste

Low-level radioactive waste contains material with radionuclide content above unconditional clearance levels and exemption quantities that have been established in Canada, but generally has limited amounts of long-lived radionuclides. Low-level radioactive waste requires isolation and containment for periods of up to a few hundred years and is suitable for disposal in near surface facilities.

Low-level radioactive waste includes the following sub-classes:

  • Very low-level radioactive waste has a low hazard potential and is above the criteria for unconditional clearance levels and exemption quantities. Long-term waste management facilities for very low-level radioactive waste do not need a high degree of containment or isolation.  Concentrations of longer-lived radionuclides in very low-level radioactive waste are generally very limited.
  • Very short-lived low-level radioactive waste includes radioactive waste containing only short half-life radionuclides typically used for research and biomedical purposes. The main criterion for very short-lived low-level radioactive waste is the half-life of the predominant nuclides. In general, the management option of storage for decay for very short-lived low-level radioactive waste should only apply to radionuclides with a half-life of 100 days or less.  

Uranium mine and mill tailings

Uranium mine and mill tailings are a specific type of radioactive waste generated during the mining and milling of uranium ore and the production of uranium concentrate. In addition to tailings, mining activities typically result in the production of large quantities of waste rock as workings are excavated to access the ore body. The wastes contain long-lived radionuclides that do not decrease significantly over extended time periods and are contained in engineered surface and near-surface waste management facilities located near the mines and mills. 

Where does radioactive waste come from?

Radioactive wastes have been produced in Canada since the early 1930s when the first radium mine in Canada began operating at Port Radium in the Northwest Territories. The pitchblende ore mined from Port Radium was taken to Port Hope, Ontario where it was refined, initially to extract radium for medical treatments, and later to extract uranium. After closing in 1940 and then reopening in 1942, the extracted uranium was used for military purposes. It was not until the 1940s that research and development on the application of nuclear energy to produce electricity began at the Chalk River Laboratories (CRL) of Atomic Energy of Canada Limited (AECL).

Radioactive waste is a by-product of the use of nuclear technology. Radioactive waste is generated during various stages of the nuclear fuel cycle, including uranium mining, refining and conversion, nuclear fuel fabrication, nuclear power and research reactor operations, and eventual decommissioning of nuclear facilities.

Radioactive waste is also generated by other activities and facilities such as:

  • Medical activities – radioactive materials are used for a number of purposes in the medical industry, including hospital and laboratory diagnostic procedures and treatment of illnesses, and equipment sterilization
  • Industrial activities – the industrial sector uses radioactive materials for non-destructive testing of materials and components
  • Research activities – academic and industrial research using radioactive materials can produce a small amount of radioactive waste
  • Nuclear or radiological emergencies – in the unlikely event of a nuclear or radiological incident, radioactive waste could be generated

Managing radioactive waste

Radioactive waste management refers to all activities involved in the handling, pre-treatment, treatment, conditioning, transport, storage, and disposal of radioactive waste.

Federal oversight: Nuclear Fuel Waste Act

In 2002, Parliament passed the Nuclear Fuel Waste Act (NFWA). This legislation required nuclear energy corporations to establish a waste management organization, the Nuclear Waste Management Organization (NWMO), as a non-profit entity to manage the long-term management of Canada’s nuclear fuel waste.

Under the NFWA, the Government of Canada is responsible for reviewing the study of long-term management options prepared by the NWMO, selecting a long-term option from those proposed, and ensuring oversight during its implementation. After a comprehensive three-year study and public engagement, the Government of Canada selected the NWMO's Adaptive Phased Management approach for the safe and secure long-term management of used nuclear fuel. The NWMO is currently in the site selection process.

Read the Federal Oversight of the NFWA


The term decommissioning refers to the administrative and technical steps to allow some or all of the regulatory control to be removed from a facility, location or site, where nuclear substances are managed, used, possessed or stored. Decommissioning activities are the procedures, processes, and work activities (e.g., storage with surveillance, decontamination, dismantling, or cleanup and remediation) that are taken to retire a facility, location or site from service with due regard for the health and safety of people and the environment. Decommissioning may produce waste that is radioactive, hazardous, or both.  

The decommissioning strategy taken is highly dependent on the individual case. In Canada, three decommissioning strategies can be considered, either individually or in combination:

  • Immediate (prompt) decommissioning – to decontaminate, dismantle and/or clean up without any planned delays.
  • Deferred decommissioning – to place the facility, location, or site in a period of storage with surveillance followed by decontamination, dismantlement, and/or clean up, or to conduct activities directed at placing certain buildings, facilities, locations, or sites in a safe, secure interim end-state, followed by a period of storage with surveillance, and ultimately decontamination and dismantlement.
  • In-situ decommissioning – to place the facility, or portions of the facility, in a safe and secure condition, in which some or all of the radioactive contaminants are disposed of in place, which may result in the creation of a waste disposal site.

In cases where the end-state for in-situ decommissioning results in a waste disposal site, the project proponent is required to satisfy all regulatory requirements for a radioactive waste disposal facility and demonstrate safety via a safety case and safety assessment of the disposal facility.

As elaborated in the CNSC REGDOC-2.11.2, in-situ decommissioning cannot be considered a reasonable decommissioning option for planned decommissioning of existing or future nuclear facilities and situations where removal is possible and practicable. In-situ decommissioning may be considered a solution only under exceptional circumstances (e.g. following a severe accident) or for legacy sites. Legacy sites specifically refer to research and demonstration facilities, locations or sites dating back to the first use of nuclear technologies in Canada for which decommissioning was not planned as part of the design.

In-situ decommissioning for legacy sites is only considered viable in situations where:

  • it can be carried out in a manner which is protective of workers, the public, and the environment
  • decommissioning was not planned as part of the design
  • the fuel has been removed; and the site will remain under institutional control for the period defined in a site specific safety case that is acceptable to the regulator

In-situ decommissioning with a disposal end-state is an accepted practice for uranium mines and mills.

How is the long-term management of radioactive waste and decommissioning paid for?

As a part of the regulatory framework, the CNSC administers REGDOC-3.3.1, Financial Guarantees for Decommissioning of Nuclear Facilities and Termination of Licensed Activitiesdocuments in this series provide information on financial guarantees used to ensure a licensee will have sufficient funds to decommission a licensed location and dispose of any associated nuclear substances.

The Nuclear Fuel Waste Act establishes the oversight that the Government of Canada and the Minister of Natural Resources will exercise in regards to the long-term management of nuclear fuel waste in Canada. This oversight includes ensuring that audited financial statements indicate the required monies are being set aside by waste owners in established trust funds to enable the long-term management of their nuclear fuel waste.

Integrated Strategy for Canada’s radioactive waste

Canada is safely managing its radioactive waste today and already has several long-term plans and projects in place. However, long-term solutions need to be put in place to address certain waste streams that do not have disposal plans, specifically for intermediate-level and some low-level radioactive waste. To address this, the Nuclear Waste Management Organization (NWMO) was asked by the Minister of Energy and Natural Resources to engage with Canadians and Indigenous Peoples and lead the development of an Integrated Strategy for Radioactive Waste. In 2023, the NWMO submitted the Strategy to the Minister. The Strategy represents an important first step to ensuring waste owners put in place disposal plans for all of Canada’s radioactive waste. To read the Minister’s statement on the Strategy, you can visit Statement from the Minister on the Integrated Strategy for Radioactive Waste. To read the strategy, please visit the Integrated Strategy website.

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