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Aecon VPs highlight challenges of Darlington refurb

Don Wall
Aecon VPs highlight challenges of Darlington refurb
AECON — OPG president and CEO Ken Hartwick stated in a release that with the completion of the initial Re-tube and Feeder Replacement project at Darlington Unit 2, the four-unit Darlington refurbishment project is one step closer to its planned 2026 completion.

The success of the first phase of the Darlington Nuclear Generating Station Refurbishment Program firmly establishes joint venture design/construction partners Aecon Group and SNC-Lavalin at the forefront of the nuclear sector worldwide say two Aecon executives.

The firms were awarded a $2.75-billion contract by Ontario Power Generation (OPG) to carry out the Re-tube and Feeder Replacement project for Unit 2 of the Darlington plant in January 2016, and the refurbished plant was officially announced as reconnected to Ontario’s electricity grid on June 4. The plant is located in Clarington, east of Toronto.

Thomas Clochard and Sean Sexstone, senior vice-presidents in Aecon’s Nuclear division, praised the teamwork of all involved, singling out the “grit” of boilermakers who came through at a critical time in the project and also of the team decision to create a complete full-scale mock-up of the unit for training purposes as key factors in the accomplishment.

“In general, in the nuclear industry, having a megaproject of this size be on time and on budget is something that just doesn’t occur,” said Sexstone. “So the significance for us, obviously we are really proud of the work our team has collectively been able to do with OPG.”

“You see nuclear projects all around that tend to slip, they have issues, the schedule slips, the budget slips, so I think what we are doing in Canada, it sets Aecon up to be part of the premier nuclear constructors. It certainly shows the nuclear industry these can be done.”

Work on Unit 2 began in October 2016 when the unit was disconnected from Ontario’s electricity grid. After defuelling, the next stage was to dismantle and reassemble the reactor. The team was all set to throw themselves into the work because of the extensive time that had been spent at OPG’s Mock-up and Training Facility, located at the Darlington complex.


Over the course of the Darlington Unit 2 refurbishment, some 480 fuel channels and calandria tubes were replaced; over 27 kilometres of pipe, including pressure tubes, calandria tubes and feeder pipe, were installed; and nearly 4,000 radiographic welds were completed.
AECON — Over the course of the Darlington Unit 2 refurbishment, some 480 fuel channels and calandria tubes were replaced; over 27 kilometres of pipe, including pressure tubes, calandria tubes and feeder pipe, were installed; and nearly 4,000 radiographic welds were completed.


Approximately 1,500 trades workers spent 750,000 hours training at the complex. Besides boilermakers, other trades with major roles on the refurbishment were millrights, electricians, pipefitters, carpenters and labourers.

“They were able to go in and see, feel, touch,” said Sexstone of the training facility. “Step by step, they got to practise, and got a lot of oversight.”

Clochard pointed out the training also contributed to excellence in health and safety standards on the job among other benefits.

“It was really important for their safety and quality of work and for operational performance from a scheduling and budget point of view to have this mockup built and have our workforce trained on it,” he remarked.

But no amount of training was able to prepare the team for the challenges associated with installing the feeder pipes into the reactor. Sexstone said this is an issue at every nuclear project around the world. At Darlington, the team feared falling behind schedule as production targets were missed.

“The series has always been difficult,” he said. “We couldn’t have done it without the trades. It was in the scope of work of the boilermakers, it is all about welding and getting the weld correct.

“We changed some processes, parameters. Really it was the grit of our trades and some of our management staff who got us back to where we needed to be from a production standpoint.

“It was neat to see everybody rally behind it. I had never seen it before in my career.”

Then, Clochard noted, when the project was in the homestretch early this year, the COVID-19 pandemic hit.

“We worked in a very challenging environment and we took very aggressive measures to protect our people,” he said. “We have done that with no cases within our workforce at Darlington, no onsite contamination and we delivered for OPG and for the province.

“I think we have our people to thank for that.”

Next up for Aecon will be the refurbishment of Darlington Unit 3, followed by 1 and 4. The Bruce plant will also be refurbished.

“This is the first step in our participation in the whole program of Ontario nuclear refurbishment,” said Clochard. “We are very proud of that first step and we are starting to work with our partner SNC-Lavalin and with our client for the next units.”


Follow the author on Twitter @DonWall_DCN.

Recent Comments (1 comments)

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Dean Image Dean

Worked at this facility for 6 months, thumbs up in all accounts, training,professionalism,execution,facility,cleanliness, would not hesitate to go back.


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