Darlington nuclear power plant refurbishment crosses halfway mark

A decade-long project to extend the station’s life by 30 years began in 2016.

The 10-year, multi-billion-dollar Darlington nuclear power plant refurbishment for Ontario Power Generation has crossed the halfway point and is on track to be completed on schedule, the power utility said in a late September press release.

Refurbishment work on the four nuclear reactors at Canada’s second-largest nuclear station began in October 2016. 

The Unit 3 project team is working through reactor reassembly, and the unit’s refurbishment work is more than 75% complete. Fuel channel installation was completed in mid-July, requiring the installation of 480 calandria and pressure tubes, 960 end fittings and other components. With fuel channels installed, lower feeder installation is underway, OPG said. 

Project teams used lessons learned from Unit 2, which, in 2020, was the first Darlington reactor to be refurbished, to trim time off of the schedule for Unit 3 retube and feeder replacement work.

Fuel reloading is expected to take place later this year and the unit is slated to return to service by mid-2023.

Work to defuel Unit 1 began last spring as the unit began its own 39-month refurbishment. Fuel removal involved using remote-controlled tooling to remove 6,240 fuel bundles from the reactor. Bulkheads were installed to island Unit 1 from the other operating units. OPG and its project partner, CanAtom Power Group, are reportedly preparing the reactor vault for the disassembly phase.

The final unit to be refurbished–Unit 4–is slated to start work in the third quarter of 2023. It has an expected return-to-service date in the fourth quarter of 2026.

The C$12.8 billion ($9.37 billion) project is expected to enable Darlington to generate electricity for an additional 30-plus years.

The Darlington station is made up of four, 878 MW CANDU reactors, which entered service between 1990 and mid-1993.

In October 2021, nuclear equipment firm BWXT’s Canadian subsidiary partnered with GE Hitachi Nuclear Energy on an engineering and procurement deal to support design and manufacturing of a small modular nuclear reactor at the Darlington station. The agreement aimed to facilitate development work on the BWRX-300 SMR, a 300-MW water-cooled reactor that is an evolution of the boiling water reactor design.