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A PTC-35 ring crane with a capacity of 1,600 tons is at the center of the largest ongoing nuclear maintenance operation in Canada: the replacement of eight steam generators in Unit 4 of the Bruce Power plant in Ontario, a project that will extend the plant’s lifespan for decades.
The Bruce Power nuclear plant, located in Ontario, Canada, is responsible for supplying more than 30% of the province’s entire electricity demand, and also for producing medical isotopes used in cancer treatment for patients around the world. Keeping this structure operating safely and efficiently for more decades requires engineering interventions that few pieces of equipment on the planet can execute. It is for this work that the Dutch company Mammoet returned to the plant with a crane of capacity rarely seen outside large industrial or offshore projects.
The ongoing operation involves the replacement of eight steam generators and the repositioning of two steam drums in Unit 4 of the Bruce A Station, a direct continuation of the work already carried out in Unit 3 in 2024. The process is expected to last six months and uses the same PTC-35 ring crane with a capacity of 1,600 tons that proved its efficiency in the previous stage, in addition to self-propelled platforms and jack-and-slide equipment for moving the enclosed components.
The plant that lights up Ontario and treats cancer
Bruce Power is not an ordinary plant. Operating with six reactors distributed between Bruce A and Bruce B stations, units 3 to 8, the complex is one of the largest nuclear energy generators in the world and a central piece of the Canadian province’s electrical matrix. More than 30% of the electricity consumed in Ontario passes through there, which makes each maintenance stop a meticulously planned event with considerable logistical impact.
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Besides electricity generation, the plant has a less known but equally critical role: the production of radioactive medical isotopes used in cancer diagnostics and treatments.
These materials are generated as a byproduct of the reactors’ operation and distributed for clinical use in various parts of the world. Any extension of the plant’s lifespan is, therefore, also an extension of the capacity to produce these essential compounds for nuclear medicine.
The MCR Project and What is Being Replaced
The Major Component Replacement Project, known by the acronym MCR, began in 2020 and encompasses the replacement of critical components in six reactive units.
The current operation in Unit 4 is executed by Mammoet in partnership with the Steam Generator Replacement Team (SGRT), a joint venture equally shared between Aecon and SGT, a partnership formed by Framatome and United Engineers and Constructors.
The technical scope of the intervention includes the replacement of eight steam generators with expired lifespans and the repositioning of two steam drums. The removed generators will be transported by self-propelled modular transporters (SPMTs) to a long-term storage area within the complex itself.
Each component weighs enough to require equipment that most conventional civil works would never need to mobilize, and it is precisely here that the PTC-35 crane becomes an irreplaceable piece of the operation.
Why a 1,600-Ton Crane and Not Another
The choice of the PTC-35 ring crane was not arbitrary. In highly complex industrial environments like a nuclear plant, each equipment decision carries safety, time, and cost implications that multiply over months of operation.
Gord Gilchrist, director of business development at Mammoet, explains the reasoning precisely: a crawler crane with equivalent capacity would require a huge counterweight that would need to be constantly lifted and repositioned with each movement, which adds risk, consumes time, and occupies space that simply does not exist in a nuclear plant.
The PTC-35 solves this problem through its own architecture: the ring design distributes loads in a way that eliminates the need for a conventional counterweight. But there is another decisive advantage for the Canadian context: the crane can remain erected in extreme wind conditions, anchored by a specific storm system.
At the Bruce Power site, strong winds are a frequent reality, and a conventional crawler crane would have to lower the boom with each intense gust, paralyzing the operation and compromising the six-month schedule.
What it means to extend the lifespan of a nuclear plant
Extending the operation of a nuclear plant is not just a technical decision, it is an energy, economic, and climate decision with long-term implications. Building a new plant from scratch takes decades, costs tens of billions of dollars, and faces regulatory and social resistance that is rarely resolved quickly.
Renovating an existing plant, with already installed infrastructure, trained staff, and established operational licenses, is a radically more efficient alternative.
The replacement of steam generators is the technical heart of this rejuvenation process. These components are subjected to decades of thermal pressure, radiation, and continuous operation cycles, and when they reach the end of their lifespan, they compromise the capacity and safety of the entire reactor.
Replacing them, instead of decommissioning the unit, allows the plant to continue operating for more decades with performance equivalent to a new facility, but at a fraction of the cost and time of a new construction.
Mammoet and the role of specialized companies in nuclear energy
The operation at Bruce Power is not the only nuclear project in which Mammoet is involved. The company operates globally in the construction, maintenance, and decommissioning of plants, with teams present in projects like Hinkley Point C in the UK, the Flamanville plant in France, and ITER, the international nuclear fusion research project considered the largest scientific experiment underway on the planet.
This accumulated specialization is what makes companies like Mammoet indispensable partners in a sector that operates with zero tolerance for errors. Rob Hoare, vice president of MCR project execution at Bruce Power, was straightforward in assessing the partnership: the specialized equipment made the exchanges quick, efficient, and safe, and the engineering support was critical to the project’s success. When a single failure can compromise the power generation of an entire province, having the right crane at the right time stops being a logistical detail and becomes a strategic issue.
Did you know that a nuclear plant also produces the isotopes used in cancer treatment? What do you think about extending the lifespan of existing plants instead of building new ones? Leave your opinion in the comments, this is one of the most important discussions about the future of clean energy.
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