Nuclear Generator Excitation Modernization for Reliability and Stability

Technology deployment at Ontario’s Bruce Nuclear Generating Station will support reliable, low-carbon electricity generation by modernizing critical generator control systems. The multi-year contract reinforces ABB’s position in the nuclear market and addresses key operational challenges for large reactor fleets.

What Technology Is Being Deployed and Why It Matters
ABB has been selected by Bruce Power to replace the existing excitation systems on eight reactor units at the Bruce Nuclear Generating Station in Ontario, Canada. The contract, booked in late 2025, covers installation of ABB’s UNITROL^® 6000 X-power excitation systems across both Bruce A and Bruce B units. These systems provide real-time control of generator field currents, enhancing grid stability and machine reliability during varying operational conditions. The upgraded systems are engineered specifically for the demanding environment of nuclear generators, ensuring synchronous machines maintain stable operation and meet stringent grid code requirements. Delivery of the first systems is expected by the end of 2027, with engineering and design work taking place over the preceding two years.

How the Upgrade Supports Nuclear Performance and Safety
Excitation systems play a core role in controlling generator voltage and dynamic response during load changes or grid disturbances. The modernized systems will improve operational efficiency, reliability and safety, extending the service life of Bruce Power’s existing reactors without the need for new builds. By reducing unplanned outages and improving machine control fidelity, the technology supports dependable electricity output from units that are part of a broader life-extension and major component replacement program.

Contribution to Low-Carbon Energy Goals
Nuclear power is a central component of Canada’s low-carbon energy strategy. It accounts for roughly 15 % of national electricity production and over 50 % in Ontario, forming the backbone of the province’s electricity system. Maintaining and upgrading this generation capacity helps avoid reliance on emissions-intensive sources like natural gas and supports national decarbonization goals. Modernizing excitation systems helps ensure these nuclear units remain available and compliant with operational standards well into the coming decades.

Differentiation: ABB’s Expertise and Local Industrial Integration
ABB’s contract with Bruce Power underscores its longstanding expertise in excitation technology for nuclear generators and its leadership in North American nuclear supply. The UNITROL systems for this project are built in Canada, leveraging ABB’s Centre of Excellence in Montreal, which combines nearly 50 years of specialized experience in nuclear generator control solutions. This local manufacturing base, combined with advanced simulation models and engineering services, distinguishes ABB’s offering from generic excitation system suppliers. The proximity of field engineers to the Bruce site also enhances responsiveness for commissioning and long-term support.

Integration With Bruce Power’s Broader Modernization Effort
The excitation system upgrade is part of Bruce Power’s ongoing Life-Extension Program and Major Component Replacement Project, which is systematically refurbishing key systems across Units 3–8 to ensure continued operation through the 2030s. Other modernization work at the station, such as advanced steam turbine and generator replacements, complements the excitation system upgrade by increasing capacity and efficiency across the fleet. Together, these efforts maintain the plant’s contribution to Ontario’s electricity supply while extending the operational life of aging infrastructure.

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