Darlington Nuclear Refurbishment
Province: Ontario
City/Region: Clarington
Image Credit: Ontario Power Generation
6
Project Rank
Project End: 2026
Project Type: Nuclear
Industry Sector: Energy
Project Amount: $12.8 billion
Date of Completion: 2026
Funding Source: Public
Provincial Funding: $12.8 billion
LEED Status: Certified
Previous Rankings
| 2025 | 4 |
| 2024 | 4 |
| 2023 | 4 |
| 2022 | 4 |
| 2021 | 3 |
| 2020 | 3 |
| 2019 | 2 |
| 2018 | 2 |
| 2017 | 2 |
| 2016 | 15 |
| 2015 | 17 |
About The Project
The Darlington Nuclear Refurbishment Project was managed in three distinct phases: Initiation Phase (2007Ð2009); Definition Phase (2010-2015); and Execution Phase (2016-2026). In November 2024, OPG announced the completion of the refurbishment of Unit 1 five months ahead of schedule. The refurbishment of Unit 1 involved the successful removal and replacement of major components of the reactor and its associated equipment including pressure tubes, calandria tubes and feeder pipes, as well as inspection and upgrades of the turbine generator equipment. Unit 1 is the third of four units that have been successfully refurbished to date, with the overall project tracking on-time and on-budget. Unit 4 is tracking to be completed by 2026.
Project Owner: Ontario Power Generation
Project/Construction Manager: Aecon Group Inc. / AtkinsRéalis JV (execution phase of the retube and feeder replacement)
Engineer: Wood (WSP) (environmental)
Contractor: Generation: Andritz Hydro Canada, Astaldi Canada, Barnard-Pennecon JV Transmission: GE Energy (formerly Alstom Grid Canada and Alstom Renewable Power Canada), Andritz Hydro Canada, H.J. O’Connell Construction, Valard Construction; Bird Construction
Other Key Players: E.S. Fox; GE Power; ABB; Amec Foster Wheeler; Deloitte; Kiewit; Black & McDonald; Tetra Tech; BDI Canada; Burns & McDonnell/Modus (Independant Project Oversight); Cameco (calandria tubes and annulus spacers); Alstom AA6Power & Transport Canada Inc. (turbine generator refurbishment); Hatch (engineering services); Armtec; Accenture (management consultant); Golder (WSP) (geotechnical services); Dillon Consulting; KPMG; Wood (WSP) (geotechnical studies)
Other Suppliers: DECAST Ltd.; Laker Energy (nuclear components); Nu-Tech Precision Metals (calandria tubes)
Legal: Blake, Cassels & Graydon; Torys (acting for the owner)
Key Players
Key Players’ recognize the organizations whose work, knowledge, and expertise go into constructing and delivering the significant projects that make our annual list.
Gold (15-19 Projects)
Silver (10-14 Projects)
Bronze (5-9 Projects)
- ACCIONA Infrastructure Canada
- Accuracy
- Alstom
- Associated Engineering
- Black & McDonald
- Blake, Cassels & Graydon
- Cartel Communication Systems
- COWI
- Davies Ward Phillips & Vineberg
- DECAST Ltd.
- DIALOG
- EBC Inc.
- FlatironDragados
- GeoVerra
- HDR
- Hemmera
- Infrata
- Kasian
- Lakeland Consulting Inc.
- Lavery, de Billy
- LRI Engineering
- McMillan LLP
- Montrose Environmental
- Mott MacDonald
- Mulvey & Banani
- NORR Architects & Engineers Ltd.
- Osler
- Parkin Architects Ltd.
- Plenary Americas
- R.V. Anderson
- STRABAG Inc.
- Tiree
- Torys

