10 builders at the core of Canada’s nuclear program

The data is in. This year’s Top 100 Projects list shows nuclear work is a force to be reckoned with in Canada. The combined project value of major nuclear infrastructure work being done adds up to $73.5 billion. Just two nuclear projects alone totalled nearly $50 billion and of the top six spots on the list, four were nuclear projects.

The epicentre of it all is to the east. For decades, nuclear power has been quietly supplying more than half of Ontario’s electricity, and the province is doubling down on this strategy. Their nuclear expansion plan is expected to create 150,000 new job opportunities and add over $800 billion to Canada’s economy. Just refurbishments alone are forecast to maintain more than 12,000 MW of existing generation capacity, enough to power 12 million homes.

Ontario’s nuclear buildout now centres on four big projects: OPG’s Darlington New Nuclear program will add four BWRX-300 small modular reactors (about 1,200 MW) with the first unit targeted around 2030; the Darlington Nuclear Refurbishment is extending the life of OPG’s existing Darlington units through a multi-year overhaul program; Bruce Power’s refurbishment and major component replacement work on Units 3–8 at Tiverton is pushing operating life into the early 2030s; and Ontario is also advancing life-extension work at Pickering to keep near-term supply on the grid while new capacity and refurbishments ramp up.

More work is on the horizon that could push the Top 100 list value even higher in the coming years. Ontario says it plans to build the first large-scale nuclear facilities in Ontario in over 30 years and is exploring two sites: Ontario Power Generation’s Wesleyville site at Port Hope (10,000 megawatts) and the Bruce C project (4,800 megawatts).

But without high technical exertise, none of it gets done. Here are some of the major contractors helping carry out this complex work:

Aecon

Aecon is one of the most deeply embedded delivery players across Ontario’s nuclear work: it’s part of CanAtom (AtkinsRéalis & Aecon) on Pickering’s EPC scope, part of Aecon Kiewit Nuclear Partners on the Darlington New Nuclear SMR build, and is also a core contractor/JV participant supporting Bruce Power’s refurbishment work. Aecon is additionally in a JV with AtkinsRéalis for Darlington refurbishment execution-phase retube/feeder replacement delivery. Since 1967, Aecon says it has served Ontario’s nuclear industry through a full spectrum of nuclear EPC services, plus maintenance, manufacturing, modularization/fabrication and decommissioning. Other notable nuclear work includes Bruce Power’s Fuel Channel and Feeder Replacement, the Darlington Nuclear Refurbishment, and the Bruce Power Steam Generator Replacement delivered through the SGRT joint venture structure it describes.

AtkinsRéalis

In Ontario’s nuclear buildout, AtkinsRéalis is a core integrator across the biggest files: it co-leads CanAtom (with Aecon) for Pickering’s EPC scope, is helping build Darlington New Nuclear SMR project, and forms an Aecon/AtkinsRéalis JV serving as project/construction manager for the Darlington Nuclear Refurbishment execution-phase retube/feeder replacement, while also appearing within the Shoreline JV supporting work at Bruce Power. AtkinsRéalis says it has end-to-end nuclear capabilities across the lifecycle—ranging from new-build reactor design/consultancy and site-based commissioning, through reactor support and life extension (including involvement in refurbishments for Bruce Power and OPG), and into decommissioning and environmental remediation services (including spent fuel management support and legacy site clean-up), supported by digital engineering tools aimed at improving safety, cost, and schedule performance.

Kiewit (Kiewit Nuclear Canada)

Kiewit is a front-line constructor in Ontario’s new-build program through Aecon Kiewit Nuclear Partners on the $20.9B Darlington New Nuclear Project in Bowmanville, Ont., and it’s also among the key players connected to the $12.8B Darlington Nuclear Refurbishment in Clarington, Ont. In its nuclear positioning, Kiewit emphasizes direct-hire delivery and fully integrated engineering and construction spanning the full lifecycle—from preliminary design and nuclear-grade procurement to NQA-1 quality construction—and says it supports both nuclear security and commercial nuclear work via EPC services for advanced and small modular reactors, plus plant modernization/life-extension, research/test facilities, fuel fabrication and waste management. It also highlights experience across contract models (ECI/FEED/EPC/progressive design-build), a constructability/risk-led approach to schedule certainty, and heavy self-perform to maintain consistent quality and oversight.

E.S. Fox

E.S. Fox is a key delivery contractor supporting Ontario’s major nuclear programs (including Pickering, Bruce and Darlington). In its nuclear positioning, E.S. Fox describes itself as a single-source nuclear EPC provider offering engineering, fabrication, construction and maintenance, with millions of hours supporting Ontario’s nuclear fleet and stated readiness to support the shift toward SMRs while continuing refurbishment work. The company emphasizes a nuclear QA/QC program aligned to CSA N286-12 / N299.1 / N285.0 requirements, outlines in-house nuclear fabrication/design capabilities (including pressure-boundary and non-pressure-boundary equipment), and notes on-site offices at Darlington, Bruce, Pickering, and CNL Chalk River to keep teams close to execution.

BWXT Canada

BWXT Canada has built itself up as a specialized supporter of Ontario’s major programs (including Pickering, Bruce, and Darlington). In its corporate profile, BWXT Canada describes 60+ years of experience designing, manufacturing, commissioning, and servicing nuclear power generation equipment—spanning CANDU and PWR steam generators, nuclear fuel and fuel components, and other critical plant components and services. It employs about 1,290 people, and operates across multiple Ontario locations (including Cambridge, Peterborough, Port Elgin, Pickering, Toronto, Arnprior and Oakville). BWXT also notes it has supplied more than 305 CANDU and PWR steam generators worldwide, and delivers services via staff augmentation, scoped projects, or turnkey delivery.

Black & McDonald

Black & McDonald is a regular delivery player across Ontario’s major generating-station programs (including Pickering, Bruce and Darlington), reflecting its long-running presence in the province’s nuclear construction and maintenance ecosystem. In its nuclear services positioning, the company describes itself as a single-source, multi-trade provider delivering nuclear EPC solutions, and says it partners with OPG to engineer/procure/construct multi-trade projects, provides maintenance and facility management services for the Darlington Refurbishment, and manages station operations at Pickering Nuclear, Darlington Nuclear, Bruce Power, and the Western Waste Management Facility. It also cites 17.7 million labour hours on nuclear construction, modifications, fabrication, outage and maintenance services across Canadian nuclear generating plants.

Framatome

Framatome is a major global nuclear OEM and services provider that describes itself as an international leader supplying nuclear equipment, services, and fuel to support reactor safety and performance, with 60+ years of experience across work on 380+ reactors worldwide. In the Ontario context reflected in the Top100 profiles, Framatome’s involvement is most directly connected to Bruce Power’s refurbishment through steam generator replacement work, placing it in one of the highest-complexity component scopes on the province’s nuclear life-extension programs. Framatome also highlights Canadian delivery capabilities and footprint on its own site, including a presence in Ontario (with listings that include Pickering and Kincardine) and examples of Canadian work tied to major fleet sustainment and refurbishment activities.

Hatch

Hatch is a staple in Canada’s nuclear ecosystem, and it also has a significant long-running delivery role with Canadian Nuclear Laboratories (CNL) at Chalk River, Ontario. Hatch says it has supported CNL since 2019 (ongoing) through a Master Services Agreement for Chalk River site revitalization, with 56+ projects completed or underway and construction support across 5+ refurbishment scopes. It describes its CNL work as spanning design and architecture for new facilities, sustainability and climate resiliency analysis, nuclear technology advising, and decommissioning planning (including waste handling and characterization). Hatch also notes support for studies tied to deploying an SMR at Chalk River, along with “first-of-its-kind” system design work, including a nuclear renewable hybrid energy system concept.

GE Vernova Hitachi Nuclear Energy (GVH)

GVH is a core delivery participant on Ontario Power Generation’s Darlington New Nuclear Project in Bowmanville, Ontario, as the reactor technology provider tied to the BWRX-300 SMR. GVH describes itself as an integrated nuclear offering spanning reactors, fuel, and plant services/upgrades—covering outage services, non-destructive examinations, plant upgrades, and parts/refurbishments aimed at performance, dose reduction, life extension, and long-term asset management. GVH also highlights the BWRX-300 as a simplified SMR configuration intended to reduce construction materials (less concrete and steel) and support 24–36 month build timelines using modular/open-top construction approaches. It further notes plans (announced in 2025) to establish a Canadian BWRX-300 engineering and service centre in Ontario’s Durham Region near the Darlington site, signaling a longer-term local support footprint for deployment and operations.

Black & Veatch

In Canada’s nuclear program, Black & Veatch operates as a specialist engineering and EPCM partner focused on complex nuclear infrastructure, lifecycle asset support, and advanced reactor deployment. The firm supports utilities and public-sector owners with front-end engineering, owner’s engineer services, and program delivery for nuclear new-build planning (including SMR feasibility and siting), major refurbishment and life-extension programs, and balance-of-plant modernization. In Ontario, Black & Veatch’s work aligns with long-term investments at OPG and Bruce Power by providing nuclear-qualified engineering, risk and constructability reviews, and digital delivery systems that strengthen schedule certainty and regulatory compliance during refurbishment and sustainment activities.