Canada’s Bruce Power has completed its unit 4 Major Component Replacement (MCR) outage defuelling ahead of schedule. The defuelling was completed in just 24 days, the most efficient defuel in the history of CANDU reactors. Bruce Power’s employees, partners and skilled tradespeople improved their performance from the two previous MCR outages in units 6&3, completed in 46 and 29 days, respectively.
The eight pressurised heavy-water CANDU reactor units at the Bruce site in Ontario (Bruce A – units 1-4, and Bruce B – units 4-8) began commercial operation between 1977 and 1987. Bruce Power’s CAD13bn ($10bn) Life Extension Programme, which includes Asset Management and MCR, began in 2016. MCR, which began with unit 6 and also includes units 3-8, will extend the life of the site until 2064. Units 1&2 have already been refurbished and were returned to service in 2012. Work began on unit 3 in March 2023. Unit 6 was taken offline for the refurbishment in January 2020 and was returned to service in 2023. The Life-Extension Programme and MCR Projects will extend the operational life of each reactor by 30-35 years.
“We continue to improve our performance in each successive MCR outage with our skilled workforce leveraging innovation and lessons learned,” said Lucas Van Wieringen. Removing the 5,761 fuel bundles from unit 4 was no small task, with Bruce A’s fuel handling team leveraging strong planning, preparation and maintenance for months prior to execution.
With defuel complete, the next major milestone in the unit 4 MCR project is the chemical decontamination of the Primary Heat Transport (PHT) system prior to the start of construction activity, which begins with major component disassembly.
While Bruce Power’s first MCR outage in unit 6 was completed with an industry best safety record for large projects, it was identified prior to the unit 3 MCR that dose rates in the unit’s PHT system were significantly higher, requiring an innovative approach.
A chemical decontamination of the PHT system at Low Level Drain State was identified as the most appropriate course of action. The Chemical Decontamination project was a technically complex project that greatly reduced dose rates. It is expected that this innovation will garner the same excellent results in unit 4. The renewed unit will be loaded with new fuel bundles ahead of its restart in 2027.
“Our private investments in state-of-the-art innovative modifications to improve safety and efficiency of our defuel campaign set our teams up for success. Our continued focus on proficiency of our workforce and a high-quality schedule through planning and preparation will enable us to continue to build momentum in our Life-Extension Programme,” said Lucas Van Wieringen, Plant Manager at Bruce A.
