The vacuum building - and a brief story of an outage

OVERKILL

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If you ever take a look at Qinshan nuclear power plant in China, the CANDU units don't look much different from anywhere else in the world:
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The same is the case for Point Lepreau in New Brunswick:
1654451628533.jpg


Yet, if you look at ANY of the active nuclear plants in Ontario, which all have multiple units and a common turbine hall, you'll notice a distinct feature that sets them apart, which is a large standalone structure that looks like a huge containment vessel. This is the vacuum building.

In Ontario, since the plants were all going to be built relatively near large population centres, it was decided that the safety systems would be augmented by the fitment of a negative pressure containment system, plumbed into all the units, that could suck all the air out of a given unit in the event of an issue that might otherwise result in a release.

This is how close Pickering nuclear is to the city of Pickering:
Screen Shot 2022-01-17 at 12.30.01 PM.jpg


So, at all three of our large multi-unit sites, the vacuum building(s) are present. Pickering, being an in-line arrangement, has a single vacuum building for all 8 units. You can see it just below units 1 and 2.
Screen Shot 2021-11-20 at 12.33.14 PM.jpg


Darlington, which is just up from Pickering, is 4 units with a single vacuum building:
Screen Shot 2021-11-20 at 12.38.02 PM.jpg


Bruce A has its own vacuum building:
Screen Shot 2021-11-20 at 12.30.12 PM.jpg


As does Bruce B:
Screen Shot 2021-11-20 at 12.30.49 PM.jpg


You'll notice the design of the newer Darlington vacuum building is a tiny bit different, with it having a rounded top.

Every 10 years, scheduled for one of the shoulder seasons where demand is low, the vacuum building must be inspected. This requires taking all the units offline, which is a considerable drop in electricity production. In the case of Bruce A, that's around 3,200MW, or very similar to the current active nameplate capacity of the Pickering facility. It was scheduled for a 28 day outage but they were able to complete it in a significantly shorter timeframe due to extremely favourable results.

This is what that outage looked like:
Screen Shot 2022-06-04 at 12.21.38 PM.jpg


Gas and hydro usage (lots of hydro right now due to the freshet) increased considerably to cover this loss of capacity and emissions predictably went up with the gas usage. This was a good "dry run" for what Ontario's grid will look like if Pickering is allowed to retire in 2025 (which we are currently trying to change the course on).

The vacuum buildings were built using one giant continuous pour. Here are some pics from when Darlington was built:
tspa_0002382f.jpg

tspa_0002371f.jpg
 

OVERKILL

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Are the pictures inside of the containment structure?
The vacuum building is kind of its own containment structure, does that make sense? And yes, those pictures from Bruce are taken inside it during the inspection.
 

MolaKule

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Those are cool pics.

It amazes me sometimes how people will complain about a generation facility, or a radio station tower, or an airport close to their homes.

Well, folks, those facilities were there long before the Planning and Zoning commissions allowed development so close to those facilities.

I sincerely hope our Canadian brothers are more cognizant of the history and need of these facilities than some people I have had to deal with locally. :oops:
 

OVERKILL

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Those are cool pics.

It amazes me sometimes how people will complain about a generation facility, or a radio station tower, or an airport close to their homes.

Well, folks, those facilities were there long before the Planning and Zoning commissions allowed development so close to those facilities.

I sincerely hope our Canadian brothers are more cognizant of the history and need of these facilities than some people I have had to deal with locally. :oops:
Right now we are struggling to turn around the decision to shutter, rather than refurbish, Pickering B. I put together a website for our organization to support this endeavour:
https://savepickering.ca

The decision was made when Darlington B was still on the table as a viable project (no longer the case) and we had chosen to fully invest in the wind and solar sideshow, something that is also not going on anymore.

Pickering is supposed to, with its mid-life refurbishment, run until the 2060's, like Bruce. Pickering B is actually newer than Bruce A. So this shutdown would be 40 years premature, though it of course requires considerable investment, but it guarantees another 4+ decades of clean, reliable power.
 
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