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Commission hearing information – Darlington New Nuclear Project

The Canadian Nuclear Safety Commission (CNSC) held a Commission hearing to consider the applicability of the approved Darlington New Nuclear Project (DNNP) environmental assessment to the BWRX-300, the small modular reactor (SMR) technology selected by Ontario Power Generation (OPG).

The scope of this hearing did not include consideration of a licensing decision for a licence to construct under the Nuclear Safety and Control Act.

About the Commission hearing

The hearing for the Darlington New Nuclear Project (DNNP) was held over 3 days, from January 23 to 25, in the community of Ajax, Ontario, and virtually. All those interested were welcome to attend the Commission hearing. Registration was not required.

The Commission heard from 20 oral intervenors. This included representatives from the Williams Treaties First Nations (Curve Lake First Nation, Hiawatha First Nation, Mississaugas of Scugog Island First Nation) and from the Saugeen Ojibway Nation, as well as participant funding recipients who chose to provide an oral intervention. The Commission also heard oral interventions from the public and from representatives of non-governmental organizations, including Durham Nuclear Awareness, the Canadian Environmental Law Association, the Municipality of Durham, the Darlington Nuclear Community Advisory Council, the Radiation Safety Institute of Canada, and the North American Young Generation in Nuclear. The Commission also considered written interventions provided by several intervenors who chose not to make an oral presentation.

On April 22, 2024, the CNSC announced the Commission’s decision that the existing environmental assessment for the DNNP is applicable to the reactor technology selected by Ontario Power Generation (OPG), the General Electric Hitachi BWRX‑300 reactor.

Dates Locations Agenda
Tuesday, January 23, 2024
Wednesday, January 24 2024
Thursday, January 25, 2024

Ajax Convention Centre
550 Beck Crescent
Ajax, Ontario


Virtually at

Read the revised agenda for the Commission hearing (PDF, 309 KB) to learn more about the start times and the presentations.

Commission-related documents

The following documents are related to the application, activities and Commission decisions for the DNNP:

Application for a licence to construct a reactor facility
(external PDF, 8 MB, in English only)
An application for a licence to construct is submitted by the licensee and reviewed by the CNSC. If the application is accepted, it becomes the reference safety case for the plant.

Notice of public hearing and participant funding
(PDF, 130 KB)

Revised notice of public hearing and participant funding (PDF, 210 KB)

The notice includes information related to the purpose and scope of the hearing, participant funding, and interventions.

Agenda for the Commission hearing (PDF, 309 KB)

Revised agenda for the Commission hearing (PDF, 309 KB)

The agenda includes details regarding the date, time, location, oral presentations and written submissions.
Commission member document (CMD) 24-H2
(PDF, 1 MB)
A CMD is prepared by CNSC staff and submitted to Commission members prior to the hearing. It includes a site description, matters for consideration, public consultation and engagement details, and overall conclusions and recommendations.
Download a particular CMD for the January 2024 public hearing
(January 23–25, 2024 public hearing – OPG Darlington New Nuclear Project)
A list of documents submitted by intervenors is included in the CMD package. These interventions are considered by the Commission as part of its decision process.
Archived webcast of the public hearing (January 23–25, 2024)

The recording of the public Commission hearing webcast is available for download or it can be streamed online.

A modern web browser with HTML5 video capability is required to view the recording.

The transcripts can be requested by sending an email to or calling 1-800-668-5284 (toll-free in Canada and the U.S.).

Record of decision

The Commission publishes a record of decision that outlines the issues, findings, conditions and its decision.

Learn about OPG’s Darlington New Nuclear Project

OPG’s proposed DNNP is located on the site of the Darlington Nuclear Generating Station in the Municipality of Clarington, Ontario.

OPG is considering the construction and operation of up to 4 new SMRs at the existing Darlington site; however, the current application for a licence to construct is for 1 new nuclear reactor.

OPG currently holds a power reactor site preparation licence for the DNNP. The licence was renewed by the Commission in 2021.

  • Proposed nuclear facility
    Review the facility details, public engagement updates, licence applications, documents, and the protocol.
  • Project timeline
    Learn more about the project milestones and status.
  • Reports and presentations
    Review the various reports and presentations prepared by CNSC staff, available on the Open Government portal.
  • Webinars
    Watch a recording of a webinar hosted by CNSC staff to learn more about the licensing review.

What is a small modular reactor?

SMRs are a new class of nuclear reactors that are considerably smaller in size than traditional reactors and that may potentially supply power (usually less than 300 megawatt electric) to smaller electrical grids or remote, off-grid areas.

Watch this short video to learn more.

Learn about small modular reactors

What are SMRs and how small are they? Watch these videos to learn more.

Meet some of the CNSC specialists involved in the regulatory review process for potential SMRs. Watch these videos to learn more.

Interest in SMRs is growing across Canada. Learn about other proposed projects.

Regulation of small modular reactors

All nuclear reactor facilities, including small modular reactors (SMRs), are Class IA nuclear facilities under the Class I Nuclear Facilities Regulations. In regulating SMRs and new technologies, the CNSC can apply the same criteria used to regulate traditional reactor facilities. This will be done using a risk-informed approach, applying regulatory oversight that is in line with the risk associated with the regulated activity.

As the CNSC continues to prepare to regulate new nuclear reactors and SMRs, it is committed to keeping Canadians informed and to sharing information on new nuclear activities in Canada.

Learn how to participate in a public Commission hearing.

Indigenous consultation and engagement

The CNSC is working to transform how it works with Indigenous peoples by supporting their participation in regulatory activities and by consulting and building relationships with Indigenous Nations and communities.

The CNSC acknowledges that the DNNP is situated within the traditional lands and waters of the Michi Saagiig Anishinaabeg, the Gunshot Treaty (1877-88), the Williams Treaties (1923), and the Williams Treaties Settlement (2018).

Learn more about Indigenous consultation and engagement and funding programs.

Glossary of common terms

On this page, common terms and abbreviations often associated with the DNNP and regulatory review are explained.

Questions or comments

For further information on the public Commission hearing process or to request documents, contact the Commission Registry by email at or by telephone at 613-858-7651 or 1-800-668-5284 (toll-free in Canada and the U.S.).

If you have a general inquiry or question about the CNSC’s involvement in the DNNP, email or call 613-947-7516 or 1-800-668-5284 (toll-free in Canada and the U.S.).

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