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- Darlington new nuclear
Preparing for tomorrow’s energy needs: Darlington New Nuclear
As more sectors of Ontario’s economy move toward electrification, there will be a growing demand for clean electricity.
That’s why OPG is exploring innovative energy options to power Ontario's future – including advancements in reliable, virtually carbon-free nuclear power, which can help meet Ontario’s changing energy needs while combating climate change.
OPG’s Darlington Nuclear station is already an important part of Ontario’s clean energy future – the station provides close to 20% of Ontario’s electricity, and the Darlington Refurbishment Project will ensure this world-class generator continues to provide reliable power for decades to come.
In parallel, as Canada’s only site licenced for new nuclear with a completed and accepted Environmental Assessment (EA), the Darlington Nuclear site offers a significant solution to secure Ontario’s clean energy future.
On Nov. 13, 2020, OPG announced we are paving the way for a clean energy future by resuming planning activities for additional new nuclear generation at the Darlington site, by siting a Small Modular Reactor (SMR).
Questions & Answers
What was announced today?
On Nov. 13, 2020, OPG announced resumption of planning activities for Darlington New Nuclear, with the goal of hosting a Small Modular Reactor (SMR) as early as 2028.
What happens next?
OPG’s Darlington Nuclear station is already an important part of Ontario’s clean energy future – the station provides close to 20 per cent of Ontario’s electricity, and the Darlington Refurbishment Project will ensure this world-class generator continues to provide reliable power for decades to come.
OPG currently holds a Site Preparation Licence, granted by the Canadian Nuclear Safety Commission (CNSC). To construct and operate a new reactor, further approvals, including additional CNSC licences, would be required. These licences must be obtained through an extensive regulatory process, which would include the opportunity for public input and a public hearing.
One of OPG’s current priorities is the successful renewal of the Site Preparation Licence, which was granted in 2012 and will expire in 2022. Our application will be considered by the CNSC at a public hearing in June 2021. OPG will continue Indigenous and public outreach and communications in support of the licence renewal hearing and other project information as it becomes available.
The CNSC invites public participation in the hearing and has made available participant funding. Visit the CNSC’s website for more information on how to participate.
How would an SMR compare to the current reactors in Ontario’s nuclear fleet?
SMRs have both a smaller footprint and smaller energy output than conventional reactors, like the CANDU units currently operating at both Darlington and Pickering Nuclear Generating Stations. But unlike traditional reactors, SMRs are modular in that they are often factory constructed, with the ability to add modules to meet changing energy needs.
OPG’s current fleet of CANDU reactors each generate between 500 and 900 megawatts (MW). SMRs are smaller, ranging in size from about 1 MW to about 300 MW.
CANDU reactors and SMRs both use fission to create heat which is used to generate electricity.
What technology will be built?
No decision on technology has been made yet; however, OPG has begun work aimed at identifying potential options. In October, OPG announced advancement of engineering and design work with three grid-scale SMR developers: GE Hitachi, Terrestrial Energy and X-energy.
Work with the three developers continues and will help inform OPG on potential options for future deployment. While OPG is now working with the three developers, a technology partner has not been selected. OPG continues to be open to potential opportunities, including from other developers, in particular if they offer a strong business case that can meet our considerations and requirements for a future project.
What will it cost?
As no decisions have been made on the technology to be used, a precise estimate is not yet available. Any business case decision would be made with ratepayers in mind. The project would need to show benefit from an economic perspective, support the conclusions of the completed environmental assessment, and have the potential to be used by other Canadian jurisdictions, to achieve economies of scale and support the potential export market.
A study undertaken by the Conference Board of Canada shows strong economic benefit to Ontario from construction and 60 years of operation of a single unit in the province. According to the report, direct, indirect and spin-off related employment would result in an annual average of approximately: 700 jobs during project development; 1,600 jobs during manufacturing and construction; 200 jobs during operations; and 160 jobs during decommissioning. It would have a positive impact on direct, indirect and induced Gross Domestic Product of more than $2.5 billion and result in an increase of provincial revenues of more than $870 million.
For planning purposes, OPG envisions new nuclear capacity at Darlington as early as 2028, which will provide a new source of carbon free nuclear energy for Ontario’s future projected energy demand and support potential for deployment of SMRs to other Canadian jurisdictions interested in reducing fossil fuel use.
To meet this timeline, OPG is aiming to decide on an SMR technology by the end of 2021.
Why OPG, and why at Darlington?
OPG has operated in Durham Region for more than 50 years, and in Clarington for more than 30 years. We have earned strong community support across Durham with our safe operations, and the multi-billion dollar refurbishment of the existing units at Darlington, a project currently tracking toward completion safely, on time, and on budget. Darlington is the only site in Canada with a licence for new nuclear build and with an approved EA.
We have both the operational know-how and the project management expertise for the new nuclear project. Beyond this, deployment of SMRs in Ontario would capitalize on the existing nuclear supply chain in this province, and could enable other provinces to transition from coal; provide alternative energy options to benefit carbon intensive industries; drive national job creation and innovation; facilitate deep, economically sustainable reductions in greenhouse gas emissions; and accelerate the transition from fossil fuels to a zero emissions electrical grid in Canada.
How soon could we see a new reactor producing power on this site?
It is possible an SMR could be operating as early as 2028.
Is Ontario the only Canadian province interested in SMR technology?
No. On Dec. 1, 2019, the Provinces of Ontario, New Brunswick and Saskatchewan signed a Memorandum of Understanding (MOU) setting a framework for action on the deployment of SMRs in their respective jurisdictions. In August 2020, Alberta also signalled its intention to enter into the MOU.
Are SMRs safe? I understand none have been built to date.
Just like many other industries, nuclear technology continues to evolve and innovate. All SMR designs are evolutions of previous reactor technologies which have operated safely. These next-generation reactors have additional enhanced safety features based upon decades of world-wide reactor operating experience.
All technologies include advanced, passive safety attributes that make them even safer than the designs in operation today. Any SMR project will require licensing by the CNSC, which involves comprehensive review of the reactor design and assessment of the safety case to ensure protection for the public and environment.
OPG commits to being a net-zero company by 2040
OPG's Climate Change Plan includes ambitious goals aimed at driving efficient, economy-wide decarbonization and economic renewal.
Read morePlanning resumes on Darlington New Nuclear to help secure Ontario’s clean energy future
OPG’s Darlington Nuclear site in Clarington could soon be home to one of the province’s first Small Modular Reactors.
Read moreOPG resumes planning activities for Darlington New Nuclear
Today OPG announced resumption of planning activities to construct a grid-size Small Modular Reactor at our Darlington site in Clarington.
Read moreChronology of Darlington New Nuclear
A chronology of Darlington New Nuclear key activities and milestones including relevant documents.
New! November 2020 – OPG resumes planning activities for Darlington New Nuclear
On Nov. 13, 2020, OPG was joined by Provincial government and local municipal and business leaders to announce that planning activities will resume to construct a Small Modular Reactor at OPG's Darlington site in Clarington.
October 2020 – CNSC announces public hearing dates and availability of participant funding
The CNSC has issued a Notice of Public Hearing and Participant Funding for OPG’s application to renew the DNNP Site Preparation Licence
June 2020 – OPG submits application to renew licence for Darlington New Nuclear
OPG has submitted an application to the Canadian Nuclear Safety Commission (CNSC) seeking renewal of the licence that allows OPG to undertake site preparation activities required for new nuclear generation at OPG’s Darlington site.
OPG currently holds a Site Preparation Licence for the Darlington Nuclear site, the first of a series of licences that would be required for additional nuclear generation capacity. The current 10-year licence was obtained following the completion of comprehensive environmental impact studies and an extensive public hearing conducted by a Joint Review Panel of the CNSC and the Canadian Environmental Assessment Agency in 2012.
OPG has not yet undertaken any licensed activities on the site. However, the existing licence allows OPG to carry out activities to prepare the site for future construction, for example:
- Clearing and grubbing vegetation
- Excavation and grading of site
- Installing services and utilities required to service the future project facilities (e.g., domestic water, fire water, sewage, electrical, communications, natural gas)
- Constructing support buildings
As the licence expires in 2022, renewing the licence will help maintain the option for reliable, low carbon nuclear energy to remain a key part of Ontario’s low-emission energy mix.
With the application submitted, the CNSC will determine the timing and process for review. A decision by the commission members is expected in 2021. The application and supporting documents are available here:
June 2020 – OPG submits application for renewal of Site Preparation Licence and supporting documents
Oct. 2019 – OPG submits site preparation licence renewal plan
- OPG submits Darlington New Nuclear Site Preparation Licence Renewal Plan.
Sept. 2018 – OPG notifies CNSC of intent to apply for licence renewal
- OPG issues notification to the CNSC of our intent to apply to renew the site licence that is set to expire in August 2022.
Sept. 2018 – OPG submits mid-term report
- OPG submits a licence Mid-Term report to the CNSC, outlining the activities undertaken since the licence was granted as well as a report providing an update on the commitments made by OPG (updated April 2019) during the licencing process.
2013 to Today - OPG maintains site licence
- OPG continues to maintain the licence in accordance with the licence conditions.
Dec. 2013 - Ontario asks OPG to defer construction but maintain site licence
- Citing lower than planned power consumption growth combined with a strong supply situation, the Government of Ontario, through the 2013 Long-Term Energy Plan, requests that OPG defer the construction of new nuclear reactors but maintain the existing licence.
Aug. 2012 - CNSC issues licence to prepare site
- The CNSC issues the Licence to Prepare Site to OPG for a period of 10 years, valid from August 17, 2012 to August 17, 2022.
May 2012 - Government of Canada accepts Joint Review Panel recommendation
- The Government of Canada issues a response accepting the recommendation of the Joint Review Panel and accepting the Environmental Assessment (EA).
Aug. 2011 - Joint Review Panel submits EA report
- The Joint Review Panel submits their Environmental Assessment report to the Federal Minister of Environment, recommending that the EA be accepted.
March 2011 - Joint Review Panel conducts public hearing
- A Joint Review Panel consisting of representatives from the Canadian Nuclear Safety Commission (CNSC) and Canadian Environmental Assessment Agency, conducts a 17-day public hearing to consider OPG’s Environmental Impact Statement and licence application.
- Members of the public, Indigenous communities and various organizations and agencies present oral and written submissions.
Sept. 2009 - OPG submits Environmental Impact Statement
- OPG submits an Environmental Impact Statement (EIS) and application for Licence to Prepare Site.
2006-2009 - OPG conducts Environmental Assessment
- As required by the Canadian Environmental Assessment Act (1992), an Environmental Assessment (EA) of the proposed project is conducted, including comprehensive studies undertaken by OPG and consultation with Indigenous communities, local community members and the broader public.
June 2006 - Ontario directs OPG to initiate the federal approvals
- The Government of Ontario, OPG’s shareholder, directs OPG to initiate the federal approvals process for new nuclear generating units in response to recommendations from the Ontario Power Authority’s Integrated Power System Plan.
- The Plan calls for investment in new nuclear generation capacity in order to maintain Ontario’s nuclear generating capacity at 14,000 MWe, consistent with nuclear energy’s share of the 2005 supply mix.

Darlington New Nuclear documents
Documents for review
Accessible versions available upon request to AODA@opg.com.
- Notice of Intent for Submission of Licence to Construct Application (Dec 2020)
- Application for renewal of Site Preparation Licence (June 2020)
- Aggregate Assessment Report in support of licence application (June 2020)
- DNNP - Site Preparation Licence Renewal Activity Report - Environment (May 2020)
- 2019 DNNP Annual Report (March 2020)
- DNNP - Site Preparation Licence Renewal Activity Report - Seismic And Geotechnical (December 2019)
- DNNP - Site Preparation Licence Renewal Activity Report - Decommissioning Planning (November 2019)
- DNNP - Site Preparation Licence Renewal Activity Report - Land Use
- (November 2019)
- DNNP - Site Preparation Nuclear Safety Licence Renewal Activity Report (November 2019)
- DNNP - Site Preparation Licence Renewal Activity Report - Nuclear Waste Management (October 2019)
- DNNP Site Preparation Licence Renewal Plan (October 2019)
- OPG Mid-Term Report on the DNNP Licence to Prepare Site (September 2018)
- OPG Commitment Reports; a status update on commitments made during public hearing and EA process (September 2018)
- OPG letter to CNSC re: Intention to apply for renewal of the Licence to Prepare Site (September 2018)
- Darlington Site Environmental Risk Assessment (November 2017)
- DNNP Licence to Prepare Site (August 2012)
- Darlington Station Probabilistic Safety Assessment Summary (July 2012)
- Government of Canada response to the Joint Review Panel Report (May 2012)
- Stage 4 Archaeological Mitigative Excavation of the Brady Site (ALGQ-83) – Darlington New Nuclear EA (February 2012)
- Joint Review Panel EA report submitted to the Federal Minister of Environment (EA Report Summary) (August 2011)
- Transcripts from the Joint Review Panel public hearing (March 2011)
- Darlington New Nuclear Environmental Assessment - Environmental Impact Statement (September 2009)
- OPG Application for Licence to Prepare Site (September 2009)
Canadian Nuclear Safety Commission’s licensing process for nuclear power plants
The Canadian Nuclear Safety Commission (CNSC) is mandated, under the Nuclear Safety and Control Act (NSCA), to regulate all nuclear facilities and nuclear-related activities; including the possession, use, and transport or storing of nuclear substances in Canada.
The CNSC Information Guide “Licensing Process for New Nuclear Power Plants” provides an overview of the licences required for the various phases of a nuclear power plant lifecycle, including the many opportunities for Indigenous and public participation.