The latest performance update by Canada’s OPG on the refurbishment of the Darlington nuclear plant said final construction work on the unit 2 reactor is underway but the return of the unit to service will be delayed by four months.
“At the end of the second quarter of 2019, the final stages of construction work on OPG’s Darlington Unit 2 Refurbishment Project, involving the installation of lower feeders, were well underway,” OPG noted. “As a result of slower than expected installation of lower feeders, unit 2 will now return to service by June 2020 rather than February 2020 as previously anticipated.” However, the refurbishment remains on budget. The overall budget and schedule for the ten-year refurbishment project also remains on track.
OPG’s Darlington Refurbishment project, which began in October 2016 and involves refurbishment of all four units, is scheduled for completion in 2026 in a phased CAD12.8bn ($9.7bn, €8.4bn) project. Darlington 2 is the first unit to undergo refurbishment, which will enable the station to continue operations until 2055. Each unit will be taken out of service for three years for work to be completed.
OPG said the potential four-month extension to the return to service of unit 2 is a result of delays related to fabrication and installation of feeder tube components.
“The fabrication delays had a cascading impact that resulted in upper, middle and lower feeders being installed at the same time, creating logistical and physical challenges with overlapping work." OPG said that In response, it has increased project management leadership and oversight, and that the project team has re-sequenced the work, expanded its training efforts, deployed new tooling to assist workers, and increased the number of trade resources and supervision in the field.
"The impact of unit 2 fabrication delays have been fully resolved and will not affect future units,” OPG said. OPG also anticipates that the overall project will remain on time and budget.
OPG and its partners have now completed 85% of the Darlington 2 construction work. Installation of fuel channels, upper and middle feeders, and of reactivity safety system mechanisms were recently completed. The project team has also completed the turbine overhaul, work on steam generators and electrical systems, and all safety improvement projects.
OPG said Darlington 3 is scheduled to start refurbishment in the first quarter of 2020. The extension of the return to service of Darlington 2 will lengthen the overlap of both units but will have no impact on subsequent units.
“Design and engineering are more than 90% complete and are on track for full completion by the end of 2019," said OPG. It added that over 2800 lessons learned have been captured from Darlington 2's refurbishment to date, and are being applied to unit 3 to reduce risk and improve cost and schedule performance. All long-lead material procurement is on track.
As well as Darlington, six units at the Bruce nuclear station will also be refurbished. Pickering NPP will continue to operate until 2024 to provide baseload electricity during the Darlington and Bruce refurbishments.
