OVERKILL
$100 Site Donor 2021
On December 31st at 12PM, at 100% full power, the control rods were run into Pickering Unit 4, shutting it down for the last time.
Construction of Unit 4 started on May 1st, 1968. The unit was officially declared in service on June 17th, 1973. 5 years shovel to commercial service, it remains one of the quickest constructed CANDU units.
It's first 10 years of operation saw an average capacity factor of 81.5%, which was considerably better than the majority of its LWR peer units at the time. Indeed on-power refuelling was a considerable advantage the HWR CANDU units had over BWR and PWR light water reactors that had to be shutdown for refuelling outages. It wasn't until decades later when the Americans began to optimize and severely shorten the length of their refuelling outages that US CF would improve, eventually eclipsing the CF of the Ontario CANDU fleet.
The Pickering A units were all laid-up for a safety system (secondary fast acting) refit in the mid 1990's. It was during a period of political turmoil in the province with the provincial utility, Ontario Hydro, paying the price. Under funded and with poor leadership, performance (both electrical and civil) tanked. Morale was low and this led to poor safety reviews, mistakes and outages. Another political pivot saw the dissolution of the utility and its breakup into separate entities. It was under this framework that Pickering A units 1 and 4 were returned to service with a promise made to bring back units 2 and 3 that was reneged on, despite the success of the Unit 1 restart project (upon which the Unit 2/3 restart was predicated).
Running as a "half plant" (with two dead units in the middle), despite some control consolidation happening later on, the A units were considerably more expensive to operate than their intact B unit siblings.
Opting for the least expensive safety refit option, adding more control rods and splitting them into groups, rather than the full gadolinium injection system refit (which would have made the system the same as the Bruce, Darlington and Pickering B units), this proved to be an oft contested "safety issue" with the plant, with the B units often disingenuously lumped in with their A unit siblings, despite them featuring completely modern redundant and separate safe shutdown systems. This, along with the poor economics relative to their sibling units, is why the shutdown date of 2024 was not extended, despite there being considerable life left in the pressure tubes (another decade at least).
The focus will now shift to the B unit life extension and refurbishment project where several major upgrades are planned for the site including a deep water inlet and uprates of all the units. There is a remote chance that once the B unit refurbishment is successful that an evaluation is performed on the resurrection and complete overhaul of the A units, but this is unlikely due to the fact that it would probably be cheaper to just build new units, given the scope and scale of work, coupled with the risk of trying to bring back units that have been shuttered for 3 decades and pilfered for parts.
Construction of Unit 4 started on May 1st, 1968. The unit was officially declared in service on June 17th, 1973. 5 years shovel to commercial service, it remains one of the quickest constructed CANDU units.
It's first 10 years of operation saw an average capacity factor of 81.5%, which was considerably better than the majority of its LWR peer units at the time. Indeed on-power refuelling was a considerable advantage the HWR CANDU units had over BWR and PWR light water reactors that had to be shutdown for refuelling outages. It wasn't until decades later when the Americans began to optimize and severely shorten the length of their refuelling outages that US CF would improve, eventually eclipsing the CF of the Ontario CANDU fleet.
The Pickering A units were all laid-up for a safety system (secondary fast acting) refit in the mid 1990's. It was during a period of political turmoil in the province with the provincial utility, Ontario Hydro, paying the price. Under funded and with poor leadership, performance (both electrical and civil) tanked. Morale was low and this led to poor safety reviews, mistakes and outages. Another political pivot saw the dissolution of the utility and its breakup into separate entities. It was under this framework that Pickering A units 1 and 4 were returned to service with a promise made to bring back units 2 and 3 that was reneged on, despite the success of the Unit 1 restart project (upon which the Unit 2/3 restart was predicated).
Running as a "half plant" (with two dead units in the middle), despite some control consolidation happening later on, the A units were considerably more expensive to operate than their intact B unit siblings.
Opting for the least expensive safety refit option, adding more control rods and splitting them into groups, rather than the full gadolinium injection system refit (which would have made the system the same as the Bruce, Darlington and Pickering B units), this proved to be an oft contested "safety issue" with the plant, with the B units often disingenuously lumped in with their A unit siblings, despite them featuring completely modern redundant and separate safe shutdown systems. This, along with the poor economics relative to their sibling units, is why the shutdown date of 2024 was not extended, despite there being considerable life left in the pressure tubes (another decade at least).
The focus will now shift to the B unit life extension and refurbishment project where several major upgrades are planned for the site including a deep water inlet and uprates of all the units. There is a remote chance that once the B unit refurbishment is successful that an evaluation is performed on the resurrection and complete overhaul of the A units, but this is unlikely due to the fact that it would probably be cheaper to just build new units, given the scope and scale of work, coupled with the risk of trying to bring back units that have been shuttered for 3 decades and pilfered for parts.