End of an era - Pickering A has been retired

OVERKILL

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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.

Unit 4.webp
 
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.

View attachment 256864
Make sure they got it right - he might have said:
“We have shut down the unit, eh”? Yet meant something else 😷
 
AT first I thought your were talking about Pickering phonograph cartridges. Dyslexia you know. My thoughts are whether the Ameren nuclear plant in Central MO is entering its later stages. I was a late teenager when it was being built. I grew up in Jefferson City, 25 miles away. It's over fifty y.o. IIRC
 
AT first I thought your were talking about Pickering phonograph cartridges. Dyslexia you know. My thoughts are whether the Ameren nuclear plant in Central MO is entering its later stages. I was a late teenager when it was being built. I grew up in Jefferson City, 25 miles away. It's over fifty y.o. IIRC
Pickering A SHOULD be getting a mid-life refurbishment, but the politics that turned it into a 2-unit plant severely impacted the viability of that and now, two decades on, the condition of the two mothballed units is sufficiently questionable as to make the risk unreasonable to entertain without any existing refurbishment experience at the facility.

This is because Pickering poses some unique challenges when compared to its sisters at Bruce and Darlington where everything that could be outside containment, is, and there was a lot of simplification made, whereas Pickering was FOAK, so they went a bit overboard on redundancies and extra systems that were omitted from subsequent plants. For example, Pickering units have 16 pumps, 4 of which are spare, and 12 boilers. The A units also have moderator dump tanks, as fission can't take place in a CANDU without heavy water, so you remove the heavy water, you kill the unit. This was later deemed "not fast enough" which is what resulted in the layup and later safety refit on units 1 and 4.

The Bruce A units are being refurbished, and they aren't that much newer than the Pickering A units (and Bruce A1 and A2 have already been refurbished). Units A1/A2 are 47 years old, and A3 is 46, A4 is 45. A3 is being refurbished right now, with the expectation that it will run to at least 2064, with plans to run them even longer and potentially another refurb at that point.

Most US plants have been license extended to 60 years and several to 80 years now.

The plant you are referencing I assume is Callaway? It had all of its boilers replaced in 2005, so I assume it's got a long life ahead of it.
 
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