COVER STORY | CANDU REPLACEMENT
Learning by doing at Darlington
The CANDU reactor replacement at Canada’s Darlington NPP is ahead of time and under budget. Ontario Power Generation’s Vice President of New Nuclear Growth, Gary Rose, tells NEI how it was done
AFTER MORE THAN 30 YEARS of operations, some components of the four CANDU reactors at the Darlington Nuclear Power Plant in Ontario, Canada, had reached the end of their scheduled service life and were due for replacement. This refurbishment programme began in October 2016 but there had been more than a decade of planning beforehand to ensure the programme was flawlessly executed. The first unit to be shut down for replacement was Unit 2, which was subsequently put back into service in June 2020. However, even after the years of planning were completed, with three more reactor component replacements to complete over the course of a decade, key to keeping the project on time and on budget was the ability to take learnings from one unit and apply them to subsequent reactor replacements. “We did Unit 2 independently so we could learn all
the lessons from that programme,” explains Gary Rose, Vice President of New Nuclear Growth at Ontario Power Generation. “We then started Unit 3, applied all those lessons and we’ve seen some great success,” he adds. In the latest update on the project, Ontario Power
Generation (OPG) announced that the static commissioning for the turbine control modifications was complete and work is progressing through final field changes and software upgrades. To date, more than 90% of the work on Unit 3 is now complete. Following regulatory approvals return-to- service activities will begin and the reactor is scheduled to begin operations in the second half of 2023. “We started on
Unit 3 in September 2020 and are nearing completion of that. It will probably return to service in the middle of this year. That will be ahead of schedule,” says Rose. Indeed, at the end of 2022, Unit 3 saw 6,240 bundles of new fuel loaded into the reactor following completion of the lower feeder tube installation.
In a unique development for OPG, both Units 1 and 3 of
Darlington are being refurbished in an almost simultaneous programme. Unit 1 refurbishment began in February 2022 and it is currently around halfway complete. Reactor disassembly is progressing and will be followed by the removal of all the internal reactor components, including some 480 calandria tubes and pressure tubes. As Rose says: “Unit 1 was started in parallel with Unit 3. We started Unit 1 in January last year (2022) so we are close to the midway point of that unit.” According to OPG, the overall project has now entered its
second half. Meanwhile, planning the Unit 4 programme on the basis of the lessons learned from work done on earlier phases of the refurbishment is underway. Replacement of the Unit 4 reactor is expected to begin in the third quarter of this year. “We will start the last unit, Unit 4, later this year once Unit 3 is complete and returned to service. We will be done all four units by 2026,” says Rose. Replacing a CANDU reactor after 30 years of operations,
although part of its standard operating model, is nonetheless no easy task. Rose explains: “The main component being replaced is the reactor core. We’re
Above: Darlington station is replacing all four CANDU reactors 24 | May 2023 |
www.neimagazine.com
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49
