‘MacGyver’ ingenuity needed to land a 350-tonne Stator at Bowmanville’s Darlington Nuclear Plant

By

Published July 12, 2021 at 2:02 pm

mammoet_2

The voyage of a 350-tonne Stator – a component that converts rotational energy into electrical energy – from Poland to the Darlington Nuclear Generating Station two years ago was a time and money-saving exercise in engineering ingenuity straight out of an episode of MacGyver.

Considering the purchase and transport of the 12-metre long Stator is part of a $12.8 billion, taxpayer-funded, ten-year project (albeit one that is supposed to deliver nearly $15 billion in economic benefits to Ontarians), every little cost-saving idea helps.

General Electric was commissioned to manufacture the new stator, with assembly taking place at its facilities in Poland in the spring of 2019 before shipment to Canada.

It then began an 8,000-kilometre journey via rail from the factory in Poland before boarding the cargo ship ‘Happy River’ for the voyage across the Atlantic and through the St. Lawrence Seaway to Lake Ontario. At the Port of Oshawa, the generator was then offloaded onto a waiting barge for the short trip to the nuclear plant.

Getting it off the barge at Darlington, however, posed a challenge.

Although the power station was equipped with its own dock close to the generator warehouses, it had not been used for several decades. During this time, tonnes of silt deposited from the lake water had built up at the quayside.
The result? The barge could not get close enough to the quay to offload its valuable cargo.

That’s when Dutch-based Mammoet, a heavy transport and lifting company that has been in business for 121 years and has been on-site at Darlington since construction began on the plant nearly 40 years ago, and Burlington’s McKeil Marine, a barge company with more than 60 years experience working the Great Lakes, put their collective heads together to find a solution.

The obvious answer was to dredge the dock until there was enough draft for the barge to berth safely, but this would add a great deal of extra time and administration to the project.

Permits would be required from the local authorities, delicate environmental issues would need to be considered, and it would also come with a significant price tag. As well, the job needed to be carried out in a tight timeframe, so a major delay was not an option.

It was during their routine site inspection that the Mammoet team, along with McKeil, dug down deep into their bag of tricks to MacGyver a solution that would eliminate the need for dredging altogether.

The idea was floated that the stator would be offloaded from the ocean-going transport vessel onto a shallow draft transport barge for the last leg of its journey. The barge would be maneuvered into position, water would be pumped in to intentionally ground it, and ‘Ro-Ro’ ramps would then be used to drive the load off the front of the barge and onto the quay.

This plan involved placing the barge at a 45-degree angle to the docks, allowing the 15-metre Ro-Ro ramps to deliver the goods from the front of the barge instead of the side.

To secure the barge in this position, Mammoet’s engineers mobilized two heavy prime mover tractors and a 50t counterweight to act as bollards. Once safely moored at the Darlington quayside, they were able to slowly pump water into the barge to allow it to settle gently onto the waiting mud below its keel – providing additional stability to supplement this unconventional mooring approach. A dive survey was carried out by the team to confirm that the method was feasible.

The deck of the barge then created a stable platform of similar height to that of the adjoining dockside roadway. The team could then place the Ro-Ro ramps between the barge and the dockside, allowing them to safely offload the unit and drive it along the route to its temporary home in the site’s warehouses.

Bill Owens, senior vice-president at OPG, who said the voyage of the Stator was the first major lift and material movement for the Unit 3 refurbishment, called the off-loading process “impressive.”

“The detailed planning and the expertise in the project execution was truly remarkable,” he said. “I had the opportunity to watch the stator being transported from the barge in Lake Ontario and onto land, then moved into our East Warehouse and it was an impressive display of teamwork and skill by everyone involved.”

insauga's Editorial Standards and Policies advertising