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New Report

The Case for CANDU

Why Ontario's Homegrown Nuclear Technology Is Its Best Option In A Time Of Rising Electricity Demand

May 2023

Ontario faces energy challenges for which it has a proven solution and the opportunity to act. Geared up from major refurbishments at the province’s CANDU nuclear plants, a skilled workforce and supply chain trained on the technology create the ideal conditions to start new builds. To secure affordable energy for present and future generations, Ontario's nuclear sector and government should seize the moment and build new CANDU nuclear now.

Iconic fuel channel layout of a CANDU reactor

Executive Summary

This report answers the question “why build new CANDU reactors in Ontario now?” in three parts:

  1. Coming electricity shortfalls have firmed up ambition for new nuclear capacity.

  2. CANDU, our homegrown reactor technology, is far ahead of other options in terms of local economic benefit, fuel security, project risk mitigation, and a proven track record of success.

  3. A window of opportunity created by ongoing CANDU refurbishments offers a smooth onramp to new builds.

Capacity shortfalls call for new large nuclear

Ontario is poised for rapid growth in electricity use without the supply to meet it. As policymakers search for solutions, a sober concern for energy security, fuel and technology independence, affordability, and emissions limit the available options. In this context, attention has again turned to nuclear energy as a proven way to meet clean electricity needs without sacrificing affordability or the stability of the grid.

CANDU is far ahead of the competition

Ontario’s energy future depends, unavoidably, on delivering large power projects. Crucial to these efforts are: 1) lowering project risk, and 2) ensuring the end result meets the intended purpose (ideally with knock-on economic benefits).

We find that CANDU is the lowest-risk, highest-benefit of Canada's large nuclear options. Lowering project risk are decades of construction and maintenance experience, a fully developed supply chain and trained workforce, proven economics, and ongoing success with new-build-scale refurbishments. Meanwhile, decades of affordable power, uninterrupted fuel supply, successful exports, local jobs, community benefit, and a track record of decarbonization prove that CANDU will meet the strictest criteria for new supply once built and will continue to do so for generations.

The window of opportunity is now

Refurbishment projects at the Bruce and Darlington Nuclear Stations are a $26 billion investment into CANDU assets and, just as importantly, into people with the skills to build, operate, and regulate them. Letting opportunities in CANDU lapse with the end of these refurbishments would be an irreparable loss to Ontario’s jobs, economy, and clean energy. Alternatively, building new CANDU would preserve and grow Ontario’s hard-earned legacy as a clean energy leader and signal its openness to business investment for the long-term.

What should be done?

With urgency to meet energy needs, Ontario should consider developing and executing an inclusive plan for new CANDU alongside the BWRX-300 at the Darlington New Nuclear Site, where an existing site license would speed up timelines by nearly a decade. Meanwhile, new site development to support 10 new CANDU reactors is a “no regret action” that should begin promptly. Once firm plans are in place at the provincial level, nuclear operators and the Ministry of Energy could approach the federal government to discuss avenues of support, including funding for CANDU modernizations, heavy water production, and expedited licensing for new sites.


Tell Policymakers to Build CANDU

Take action. Add your name to call for the expansion of CANDU nuclear.​

As Canadian citizens, we are concerned by the lack of firm plans to build new CANDU nuclear power as the country fast approaches an energy crunch for which the technology offers a proven solution. We submit this petition urging the Government of Ontario to act now to ensure new CANDU is available to meet the province's energy needs with affordable, clean power.

  • As provincial and federal leaders join governments around the world in calling for an expansion of nuclear power, we must ensure we make smart technology choices.

  • A large portion of the nuclear expertise within Canada is CANDU-specific, our sector having built, operated, regulated, and innovated upon exclusively CANDU reactors. This lowers project risk compared to designs with which Canada has no experience.

  • CANDU is proven to meet the strictest criteria for new capacity additions, including:

    • Low-cost, reliable power

    • Fuel security

    • Local economic benefit

    • Indigenous partnership

    • Additions at speed and scale

    • Minimal environmental impact

  • Given the urgency of getting new builds right the first time, we must value the demonstrated success of CANDU.

  • CANDU is the only Canadian reactor design. All other nuclear-exporting nations build their own designs, and Canada should be no exception.

  • CANDU runs on natural uranium fuel, while other options force the purchase of enriched uranium from abroad. This sacrifices our fuel independence and cuts into a limited global supply of enriched uranium at a time when countries are seeking to move away from the Russian-enriched uranium that constitutes 50% of global supply. Additionally, natural uranium fuel gives CANDU a major advantage in the export market compared to Light Water Reactors.

  • Numerous other features put CANDU on par or ahead of the most advanced reactor concepts, including the production of medical isotopes for cancer treatment, factory construction of parts, naturally large safety margins, flexible sizing using standardized components, and the ability to run on a range of fuels beyond natural uranium to advanced fuels and even the spent fuel of other reactors.

  • The Enhanced CANDU 6 passed the rigorous design review by the Canadian Nuclear Safety Commission more recently than the AP-1000 received its design certification from the regulator’s American counterpart. A fully modern reactor, the Enhanced CANDU 6 is ready to deploy.


Given these vital considerations, we, Canadian citizens, call on the Government of Ontario to secure its energy future by putting firm plans for new CANDU on the agenda, including:

  • Collaborating with Bruce Power and Ontario Power Generation to develop new sites for CANDU construction.

  • Exploring the placement of 2 new CANDU units at the Darlington New Nuclear Site, licensed for 4,800 MW.

  • Helping to assemble an industry-led coalition to assist and benefit from the construction of new CANDU reactors under a shared sector vision.

  • Approaching the federal government for support, once firm plans for a CANDU project are in place, to expedite the Impact Assessment process for new sites, advance heavy water production, and fund modernizations for Enhanced CANDU reactors of other sizes.


By signing the petition, you also agree to occasional emails on C4NE activities.

Thank you for adding your voice.


Explore figures from the report.

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