Climate Change Impact Considerations

The CNSC ensures that the potential effects of climate change on the safety of nuclear facilities and of the surrounding environment, are considered throughout the nuclear lifecycle. As part of the CNSC's regulatory requirements, potential effects must be identified and mitigated appropriately.  The CNSC considers climate change using a graded approach based on level of risk.

• How the CNSC assesses the impacts of climate change on nuclear safety in Canada
  • Periodic safety reviews
  • Probabilistic safety assessments
  • Environmental risk assessments
  • Requirements for proposed new nuclear projects
  • CNSC review of flood hazard assessments
  • Environmental protection review report
• How the CNSC works with Environment and Climate Change Canada
• International collaboration
• Related links  

How the CNSC assesses the impacts of climate change on nuclear safety in Canada

CNSC licensees and proponents must consider climate change primarily through requirements related to environmental and safety assessments. These assessments take place during an environmental review for new projects, as applicable, and regularly throughout a facility’s licensing lifecycle, regardless of the licence duration. This takes place as part of these processes: the licence application, licence renewal and periodic safety review.

Climate change is addressed through periodic assessments that include the following regulatory tools:

Periodic safety reviews

Every 10 years, per REGDOC-2.3.3, Periodic Safety Reviews, nuclear power plant licensees are required to conduct periodic safety reviews (PSRs) to evaluate the facility’s design, condition and operation.

Probabilistic safety assessments

Every 5 years, a facility’s probabilistic safety assessment (PSA) is updated. A PSA includes analysis of external hazards – such as flooding, high winds (including tornadoes), and other extreme weather conditions (e.g., temperature, snowfall, drought) – and their impact on a facility. CNSC staff verify that up-to-date hazard information is included.

Environmental risk assessments

Every 5 years, nuclear facilities and uranium mine and mills licensees must update an environmental risk assessment (ERA), in accordance with CSA N288.6, Environmental risk assessments at nuclear facilities and uranium mines and mills, and REGDOC-2.9.1, Environmental Protection: Environmental Principles, Assessments and Protection Measures. The ERA evaluates the facility’s impact on the environment under normal operating conditions. With each update, the ERA also considers changing environmental conditions that could be attributed to climate change, and if there has been any resulting change to the environmental risk profile to receptors from the facility.

Requirements for proposed new nuclear projects

For all proposed new nuclear projects, the effect of the environment, including climate change, on the project over the facility’s lifecycle must also be considered as part of an environmental/impact assessment, if applicable. For new reactor facilities, licence applicants are required to take climate change into consideration in siting and design, as per REGDOC-1.1.1: Site Evaluation and Site Preparation for New Reactor Facilities, and REGDOC-1.1.2: Licence Application Guide: Licence to Construct a Nuclear Power Plant. In this manner, applicants and licensees are held responsible for considering and mitigating the effect of climate change on the safety of nuclear facilities in Canada.

CNSC review of flood hazard assessments

The CNSC requires licensees to assess external hazards, including floods and extreme weather events. CNSC staff conduct a technical review of the flood hazard assessments completed by proponents and licensees to verify that these meet regulatory requirements and align with international guidance, such as IAEA SSG-18, Meteorological and Hydrological Hazards in Site Evaluation for Nuclear Installations.

In addition, CNSC staff can use the hazard assessment components of the PSR and the PSA to evaluate safety margins based on climate change projections. Some variables that influence hazards to be assessed, such as increased rainfall triggering flood conditions, are sensitive to climate change. CNSC staff verify that up-to-date flood hazard information is included in the PSR and in updates to the PSA.

Environmental protection review reports

An environmental protection review is a science-based technical assessment conducted by CNSC staff, as required by the Nuclear Safety and Control Act. This review assesses if an applicant or licensee will make, or has made, adequate provision for the protection of the environment and the health and safety of persons. Facility-specific environmental protection review reports are published on the CNSC’s website.

Moving forward, these reports will include information on the climate change resilience of nuclear facilities in Canada, and CNSC climate change considerations through regulatory tools. Site-specific climate change considerations will include:

• a description of relevant potential changes in the climate of the project area
• the site’s sensitivities to changes in climate, and identification of climate change variables (e.g., air temperature, water temperature, precipitation, winds, lake levels, sea levels, etc.) that have a potential interaction with the physical structures, systems, and components
• evaluation of climate change related impacts:
  • an assessment of the potential interactions between the identified climate change variables and physical structures, systems, and components, and how the projected effects of climate change could impact nuclear safety and operational functions and integrity
• the CNSC’s conclusions on the safety and resilience of the facility against the impact of climate change

Read the CNSC’s environmental protection review reports.

How the CNSC works with Environment and Climate Change Canada

The CNSC and Environment and Climate Change Canada (ECCC) have a memorandum of understanding that includes collaboration related to climate change. For example, ECCC informs CNSC technical reviews by contributing expertise on climate modelling, future climate projections, and estimates of probable maximum precipitation near nuclear facilities.

ECCC also has the mandate to monitor and provide meteorological data to Canadians, to conduct scientific research regarding the mechanism and effects of climate change, and to develop science-based guidance on assessment of climate change for application when projects are subject to federal impact assessments. The Strategic Assessment of Climate Change guidance includes specific guidance on net zero plans, calculation of GHG emissions/intensity and resiliency.

Learn more about Environment and Climate Change Canada’s work on climate change.

International collaboration

The CNSC participates in several international nuclear organizations to strengthen nuclear safety at home and abroad. Learn more about the  CNSC’s international involvement.

Following the Fukushima Daiichi accident, the Nuclear Energy Agency (NEA) set up a Working Group on External Events to improve understanding and treatment of external hazards, including flood hazard and high winds, to support the continued safety performance of nuclear installations and improve the effectiveness of regulatory practices in NEA member countries.

CNSC staff have been actively participating in the working group’s activities by contributing to its reports on topics like characterization of local intense precipitation and sources of uncertainties in hydro-meteorological hazards, and by sharing ideas and documents on climate change.

Related links

• Canadian Centre for Climate Services
• Intergovernmental Panel on Climate Change
• IAEA – External Events Safety Section
• Working Group on External Events
• IAEA – Design of Nuclear Installations Against External Events Excluding Earthquakes | IAEA