Darlington nuclear refurbishment finished early and under budget, but maintenance costs remain

Ontario says the fourth Darlington reactor returned to service four months early and the overall refurbishment came in $150 million below its $12.8-billion budget. OPG has reported additional maintenance needs at Darlington, with identified items totalling roughly $2.65 billion.

Construction on the fourth and final refurbished reactor at Darlington Nuclear Generating Station concluded on Jan. 19, and initial power testing of Unit 4 is scheduled to begin later this month. The province announced the full refurbishment program cost $150 million less than the original $12.8-billion budget and is intended to extend the station's service to at least 2055. Ontario officials have cited the project’s on-time, on-budget outcome as evidence of Ontario Power Generation’s improved performance. At the same time, OPG has reported several additional maintenance needs that will require further spending. Key details: - Unit 4 construction officially ended Jan. 19, and initial power testing is scheduled later this month. - The overall refurbishment program is reported as $150 million under the $12.8-billion budget and is meant to extend Darlington’s life for decades. - OPG identified turbine rotor replacements at Darlington with an estimated cost of about $2 billion. - Additional emergent work listed by OPG includes generator stator rewinds (~$300 million), primary moisture separator replacements (~$235 million), and a Unit 2 turbine control and auxiliary upgrade (~$115 million). - Darlington was built in the 1980s–90s, has supplied roughly one-fifth of Ontario’s power historically, and its refurbishment program began in October 2016. Summary: The refurbishment project has delivered earlier completion for Unit 4 and a final cost modestly below the original budget, which provincial officials have cited as evidence of stronger project delivery. Identified follow-on maintenance at Darlington introduces additional costs and OPG has scheduled initial power testing for Unit 4 as the next step; further timing for the identified maintenance work is not specified.