OPG completes first Darlington rebuild

27 March 2020

Reconstruction of unit 2 at the Darlington nuclear power plant in Canada has been completed and the process to restart the reactor can now begin, Ontario Power Generation (OPG) has announced. The company will delay the planned start of the refurbishment of Darlington 3, scheduled to begin in May, as part of its measures to ensure stable electricity supplies during the COVID-19 crisis.

Darlington's turbine hall (Image: OPG)

Darlington 2 is the first of the plant's four units to undergo refurbishment in a CAD12.8 billion (USD9 billion) project that will enable the station to operate for an additional 30 years. The work involves disassembling the defuelled and isolated reactor, 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 reactor. The refurbishment of Darlington 2 began in October 2016, with reassembly starting in June 2018.

"On behalf of all OPG employees, project partners and vendors, I want to thank our refurbishment team on completing the final steps of construction on Unit 2 under unprecedented and extraordinary circumstances," OPG President and CEO Ken Hartwick said yesterday. "The project team continued to work safely and diligently while managing changes required as a result of the COVID-19 pandemic," he added.

The restart of the reactor will be subject to regulatory approvals from the Canadian Nuclear Safety Commission and OPG's ability to do so safely given the current COVID-19 crisis, the company said.

OPG is the largest electricity generator in Ontario, and its reactors also produce the medical isotope cobalt-60 which is used to sterilise single-use medical devices such as syringes, gloves, implants and surgical instruments.

"OPG is also taking steps to ensure a stable supply of clean electricity during the COVID-19 crisis to keep the lights on for hospitals, families and essential businesses," the company said. As part of these measures, it will continue operating Darlington 3, and temporarily delay the planned start of that unit's refurbishment. "In the coming weeks, the Darlington Unit 3 project team will determine the best time to restart the project, ensuring the required critical resources and materials are available. Critical initiatives, such as completion of Darlington Unit 2's refurbishment and preparations for the spring freshet [the thaw of ice and snow], continue as planned," it said.

Refurbishment of Darlington 1 is scheduled to begin in 2021 and unit 4 in 2023, with the entire refurbishment project scheduled for completion in 2026.

Researched and written by World Nuclear News