The refurbishment of the four CANDU reactors at the Darlington nuclear power plant in Canada has now passed the midway point with work beginning at unit 1, Ontario Power Generation (OPG) announced. Unit 2 returned to service in June 2020 following its refurbishment, while work on unit 3 began in September 2020.

The Darlington units are being refurbished in a CAD12.8 billion (USD10.1 billion) project that will enable the station to operate for an additional 30 years. The work involves disassembling the defuelled and isolated reactors, removing the components of the 480 fuel channels including feeder tubes, end fittings, pressure tubes and calandria tubes.

It also includes detailed inspections of the inside of the calandria and the holes through which fuel channels are fed and secured. These are carried out before reassembling the reactors. Project execution began, after extensive planning, in October 2016.

The first refurbished unit, unit 2, was returned to service in June 2020 and, following a short delay related to the COVID-19 pandemic, work on unit 3 began in September 2020. The disassembly phase of the refurbishment of unit 3 was completed in late October last year and it is now in the reassembly phase. The refurbishment of unit 3 is due to be completed early in 2024.

With the start of work on unit 1, for the first time on the project, two units are being refurbished simultaneously. Work on unit 1 is scheduled for completion in the second quarter of 2025. Work on unit 4, the final unit to be refurbished, is scheduled to begin in the third quarter of 2023. OPG said the overall project remains on track for completion by the end of 2026.

"The refurbishment team's successful track record on units 2 and 3, combined with detailed planning for unit 1, position us well for continued success," said OPG Senior Vice President for Nuclear Refurbishment Subo Sinnathamby.

"Continuous learning and working as a team with our vendor partners and Bruce Power have been key to our success to date. We continue to apply innovations and lessons learned to ensure even better performance as we move forward through this project."

"Refurbishing Darlington Nuclear Generating Station is key to OPG's Climate Change Plan," said Ken Hartwick, OPG President and CEO.

"This safe clean energy workhorse generates over 20% of Ontario's electricity without greenhouse gas or carbon emissions each year. Thanks to this mid-life overhaul, Darlington will continue to cleanly power Ontario's homes, hospitals and businesses for decades to come."

According to an independent report by the Conference Board of Canada, the Darlington refurbishment project is expected to generate a total of CAD89.9 billion in economic benefits for Ontario, create 14,200 jobs per year, and increase the province's GDP by an average of CAD1.40 for every dollar spent.

Researched and written by World Nuclear News