November 11, 2026
Ontario has awarded nearly $66 million in construction contracts to two Eastern Ontario companies for the Darlington New Nuclear Project (DNNP), advancing development of what the province describes as the G7’s first small modular reactor (SMR). The contracts will support construction of key facilities, create and sustain skilled trades employment, and strengthen Ontario’s domestic nuclear energy supply chain.
Gillam Construction Group, based in Carp, and Mansteel Rebar, based in Pembroke, will deliver major components of the project being developed by Ontario Power Generation (OPG) at the Darlington nuclear site.
Gillam Construction Group has been awarded a contract valued at nearly $35 million to construct the Darlington New Nuclear Project’s Administration Building. The work is expected to create approximately 100 jobs.
Mansteel Rebar has secured a $31 million contract to fabricate, supply and install reinforcing steel for five of the project’s core buildings. The contract will support approximately 100 existing jobs and add another 20 positions during construction.
Together, the contracts are expected to contribute more than $66 million to Ontario’s gross domestic product (GDP), while creating opportunities for construction workers, manufacturers and local suppliers.
Mansteel Rebar will source its reinforcing steel from Canadian steel mills, supporting domestic manufacturing and strengthening the Canadian construction materials supply chain.
The latest awards build on 14 contracts recently announced for companies in the Greater Toronto and Hamilton Area.
Gillam Construction Group and Mansteel Rebar join more than 100 Canadian companies that have signed agreements with OPG to support the Darlington New Nuclear Project.
Ontario is positioning the development as an opportunity to expand domestic nuclear manufacturing capabilities while creating new markets for Canadian suppliers, including steel producers facing international trade pressures.
The province is also supporting opportunities for Ontario manufacturers to participate in emerging international SMR markets.
Recent developments include Velan’s planned manufacturing facility in Durham Region to produce safety valves for SMR projects in Europe and BWXT Canada’s agreement to manufacture nuclear components in Ontario for Poland.
The Ontario government and OPG have established a target of directing 80 per cent of project spending to Ontario companies, with the goal of retaining more economic benefits within the province.
The Darlington New Nuclear Project is planned to include four small modular reactor units capable of generating a combined 1,200 megawatts (MW) of electricity.
According to the province, that capacity would be sufficient to power approximately 1.2 million homes.
In 2025, the Ontario government approved OPG’s plan to begin construction of the first of the four proposed reactors.
The province estimates that construction, operation and maintenance of all four units will contribute approximately $38.5 billion to Canada’s GDP over 65 years.
The project is also expected to sustain approximately 3,800 highly skilled jobs over that period, supporting long-term employment in construction, engineering, operations and nuclear technology.
Ontario has identified more than 18,000 jobs associated with advancing the broader SMR development.
The Darlington SMR development forms part of Ontario’s Energy for Generations integrated energy plan, which aims to expand electricity infrastructure to accommodate population growth, housing development, industrial investment and electrification.
According to Ontario’s Independent Electricity System Operator (IESO), provincial electricity demand could increase by as much as 90 per cent by 2050.
Nuclear generation currently supplies approximately half of Ontario’s electricity, making it a major component of the province’s energy system.
The IESO has also examined alternative generation scenarios, estimating that replacing the output of four SMRs could require up to 8,900 MW of wind and solar capacity paired with battery storage. The agency identified additional considerations involving land use and transmission infrastructure.
These assessments helped inform the province’s decision to proceed with the Darlington project.
The Darlington New Nuclear Project is receiving significant financial support from both levels of government.
Ontario has committed $1 billion through the Building Ontario Fund, while the federal government has announced a $2 billion investment through the Canada Growth Fund.
These investments are intended to support the development of new nuclear infrastructure and strengthen Canada’s position in the emerging SMR industry.
For Ontario’s construction sector, the project represents a substantial opportunity for general contractors, steel fabricators, skilled trades, engineering firms and specialized equipment suppliers.
As work progresses, the Darlington New Nuclear Project is expected to remain a major driver of construction activity, manufacturing investment and nuclear supply chain development in Ontario.
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