76 A Brief History of CANDU Reactors with Chris Adlam and Tom Hess

Intro

So, Ontario is Summer and Winter peaking our winter peak is a little less than our summer peak. But our peak demand period is those summer months and that’s when our wind farms produce the least amount of power. And during those summer months when we are running air conditioning, we’re trying to keep our seniors cool, you know all those important things. Pickering is out-producing that wind fleet by fivefold.

Al

The Rational View is a weekly series hosted by me Dr. Alan Scott, providing a rational, evidence-based perspective on important societal issues.

Hello, and welcome to another episode of The Rational View. I’m your host, Dr. Al Scott. On this episode, I am interviewing two key figures from Canadians for nuclear energy, who bring a wealth of experience on the electrical grid and nuclear energy.

A recent informal poll has suggested that a lot of people are largely ignorant about nuclear power and its use in society. A significant fraction of people interviewed think nuclear power creates carbon dioxide. Many more don’t understand that Ontario’s electrical grid is one of the cleanest in the world thanks to nuclear power, which produces 60% of our electricity.

I wanted to go to the source and understand a bit more about the history of CANDU reactors and nuclear power and the electrical grid in Ontario. As always, if you enjoy what you’re listening to, please press like on your podcast app. Share it with your friends, and join the discussion at our Facebook group. @TheRationalView.

Tom Hess is a retired independent system operator with 31 years of experience at Ontario Hydro and its successor company, the independent market operator which is now the independent electric system operator IESO. He started with field operation of transmission distribution in generating equipment and then transitioned to control room operations for the bulk of his career retiring as shifts superintendent at the IESO. Tom welcome to The Rational View.

Tom

Thank you, Scott. Pleasure to be here.

AL

Chris Adlam is an electricity system and power generation enthusiast whose interests stems from a familial history in power generation.

As his great grandfather Hubert R. Sills was a hydro electric engineer for General Electric, and his grandfather worked on some of the largest hydro installs in the world.

While always being interested in engineering, Chris’s interest in nuclear began around the time of Ontario’s Green Energy Act.

In his daily life, Chris is an IT professional who has been working in the healthcare industry for over 15 years. Chris, welcome to The Rational View. Thank you both for coming on and sharing your expertise with our listeners.

There’s a lot of misinformation out there, people just don’t realize how much nuclear power is the backbone of Ontario in terms of our electrical system. And so, I thought maybe it would be good to give a background how did we get here what is CANDU so, let’s start at the very beginning here, we take uranium we mine it, you make fuel rods, solid metal fuel rods,

Chris

We create these compressed ceramic pellets called pelleting. And those get put in inside these Zircaloy rods which get fabricated into a bundle.

We have two bundle manufacturers in Canada BWXT and Cameco. Cameco also does mining and refining portion as well. BWXT does not. Here in Peterborough we have BWXT, that creates the fuel bundles for both Pickering and Darlington, okay. Bruce power fuel bundles are created in Port Hope by Cameco.

Al

Okay, so you got these bundles of uranium and this is natural uranium in the CANDU reactor whereas in the US they have to increase the U 235 component in a process called enrichment.

Chris

Yeah, so they use a gas centrifuge. And that’s all enrichments performed Yeah, use a series of gas centrifuges to increase the level of U235 and reduce the level of U238.  Because civilian reactors can be refueled, the level of enrichment doesn’t need to be very high.

High enrichment is used for things like submarines, where you’re not refueling it.

So, you can vary the level of enrichment.

Al

 So now you have the uranium in these bundles, and the uranium atoms naturally split and release high-speed high-energy neutrons.

And these neutrons don’t create a chain reaction because they’re too fast. Correct. And so, you need a moderator that slows down these neutrons so that they can break more uranium atoms and create a chain reaction which increases the heat production.

 So, with the moderator in the CANDU we use heavy water which uses deuterium instead of hydrogen, so it’s a hydrogen with two neutrons with double the mass.

So, the water molecules themselves are a little bit heavier and they’re more apt to slow down or interact with neutrons than in Light Water Reactors.

So, you’re CANDU is more efficient at slowing down neutrons and creating this chain reaction with a lower density of initial fissile material. And then this creates heat effectively, and the heat boils water it’s carried off in a heat exchanger to a turbine, which is powered by the steam and that spins and it makes electricity.

So, this is the guts of any nuclear reactor. And the details of the fuel and the moderator are basically what changes is that correct?

Chris

Yes, yeah, they change considerably for the CANDU.

So, while it has incredible neutron economy, which is what we’re talking about with respect to using material instead, and creates that flexibility, the fuel also doesn’t last as long because it’s not enriched.

So, if we go back to our smellable, so civilian reactors, they’ll say their capped at 5%. That buys 24 months roughly of time in the reactor before you need to do refueling. Okay, we don’t have any enrichment. So you’re swapping out fuel bundles regularly.

 And so, one of the development parameters for the CANDU was, well, how do you change the fuel, you need to be able to do it online because you can’t be shutting everything down every few weeks swapping and field models.

So that’s what’s led to Darlington’s incredible record of 1106 days of continuous operation because conceivably the CANDU never really needs to be shut down for things other than maintenance. I mean, obviously there are other things that take them offline, but refueling is not one of them.

Al

Okay, okay. There’s a new word calandria what’s a calandria?

Chris

A giant vat. It’s full of water. It has all of these perforations which are your calandria tubes. There are two levels of tubing here.

 So, your, your calandria tubes that pass through the calandria. And then inside those you have your pressure tubes, which is where your fuel bundles reside. At Darlington, I think there’s 12 bundles per pressure to Bruce’s 13 and I don’t know how many are Pickering, Tom probably knows. And these bundles are swapped out by fueling machine.

And there’s end fittings on each end. And the machine just latches on to the end fitting pulls that out. Shuffles the bundles, pull out whichever one it’s going to pull out, shuffles the bundles back in. And this happens there’s one on each base of the calandria.

 So, at Pickering, there are 380 fuel channels per unit. At Darlington and Bruce there’s 480. Okay,

Tom

Pickering A the older design they had 390

Chris

 I didn’t even know that.

Tom

Because the B units were based on the CANDU 6, downsized CANDU 6. So that’s how they ended up with the 380 fuel channels.

Al

Okay, so maybe tell me these things are being replaced very frequently in the CANDU reactors. Does that mean there’s more waste from a CANDU reactor than from a normal US reactor or light water reactor?

Chris

From a volumetric perspective? Yes, we produce more fuel Bhandal waste.

From a radiological perspective no, the fissile material left in a CANDU fuel bundle is less than what comes out of the tailings of the enrichment process. But thing is we have some Well, we have the richest uranium deposits in the world.

I had a thread on that the other day, in Canada. Yeah. So, from an economic perspective, there is no case for reprocessing right now.

 In Canada, we just we have too much natural uranium. And it’s so cheap to fabricate these fuel bundles, and we can just store them, which is what we’ve been doing. But there’s no real incentive to proceed.

Yeah, exactly. So, to answer your question. Yes, we produce more of it. But it’s not a problem. It’s still a very small amount of fuel. It’s just more per unit than what gets created in the states, right? You’ve got a 24-month fuel month,

Al

and then we don’t have the waste from the enrichment process because we’re not enriching.

Chris

Correct. So, we really, there’s less waste. I think in terms of an overall footprint. We don’t have those tailings. We don’t have that enrichment cycle, but at the same time we have more fuel bundles.

Al

So, where’s the where’s the CANDU waste stored and how is it stored?

Chris

So, if you look at your maps, look at Pickering, there’s the Western Waste Management Facility anyways, they’re stored directly beside the plants.

They’re like these concrete casks this thing of Pickering they’re outside, Darlington’s are inside a large warehouse, very nice-looking casks.

So, they sit in the spent fuel pool inside the plant for eight to 10 years until they’re sufficiently cool. And then they get transferred into these concrete casks, which are lead lined and they’re made out of concrete and very, very robust structures. And then they just either go into the warehouse or they go outside.

And the ones from Douglas point, which are on the Bruce grounds are all just sitting outside. They’re all just, they were designed for external storage.

 And it’s amazing, if you look at Douglas Point, all of the spent fuel from 20 years of operation could fit on my front lawn, and I do not have a very big front lawn.

Tom

I was gonna say that when you were talking about the spent fuel earlier, we’re just heading into the nine-hockey-rink, volume of waste.

So, you picture nine regulation, hockey rinks with the bundle stacked up to the top of the boards. That’s how much waste there is from all the nuclear generation that has happened in Canada, right from the beginning, so it’s not very much volume really is very small.

You really don’t need to reprocess that waste, its low radioactivity,

I read an article back in the late 90s, where they talked about spent fuel and how quickly the radioactivity decays on them.

And one of the comments that I recall from that article was after 700 years, the only way you can have those fuel bundles affect is you break them open and you actually ingest some of the pellets. Wow

 And I’ve seen another graphic I can’t remember the exact number it had but it seems to me it was like around 120 years where the waste is the same radioactivity as mine tailings which sit outside so it’s not very long before it’s you know, almost benign I mean there’s still radioactivity, but not a huge amount

Al

is this a contrast between CANDU and light water reactor used fuel?

Tom

Well, yeah, the radioactivity in the radiated bundle is much less than the CANDU bundles coming out of the CANDU reactors. Okay, I did not know that. No, the enriched ones you have, you know other fissile material materials like plutonium and you know, some of the more intense ones.

Chris

There’s a fantastic video on YouTube and for people who haven’t seen it I implore them to do so. It’s produced by a guy that works at Bruce Power, he got permission from the plant, it’s his own project. It had nothing to do with Bruce.

And he recorded this video of moving the fuel bundles into the casks, and he’s measuring radiation levels all along the way, the entire time.

And he’s standing directly overtop of 1000s of fuel bundles sitting in the spent fuel bay, we’re talking like an Olympic sized swimming pool full of fuel bundles, and he’s right over top of it, and there’s almost nothing Wow.

 And then they move them into the cask. And they drain all the water from the cask and the cask has a you know, like a pipe or drain on the side of it. It’s wide open. And he takes his Geiger counter, and he puts it right at it. And it’s basically zero. Hmm.

Tom

I just came across a little meme, well, comic, whatever you want to call it drawn up in the 80s or 90s, about the radioactivity, how it affects you in a spent fuel bay, they have people swimming and frolicking in the fuel bay and diving down. And it’s only when you get within four, three feet so around a meter of the fuel bundles that it actually starts affecting you waters. So you know, water does a fantastic job.

Chris

You brought up something very important. And that’s about radioactivity. Okay, the most dangerous products have the shortest half lives.

Al

That makes sense, they radiate the most.

Chris

right? That’s how exposure works. Those are the products that are most rapidly going to decay.

So if you’re looking at your spent nuclear fuel, right, it’s producing all this decay heat, which is why it has to sit in that water for 8-10 years, and by the time it’s come out of that pool, all of those products have significantly decay.

It’s still producing some heat but not as much. It’s also significantly less radioactive. And the longer that material sits, the more of those products are just going to disappear. Right.

 So we can Talk about oh, let’s say for example, something has a half life of 4 million years oh my god, it’s dangerous for 4 million years. No, it’s not. If it’s got a half of 4 million years, you can just ignore it.

Al

It’s not dangerous,

Chris

You’re not getting any exposure from that. It’s the stuff with the short half lives that you need to be concerned about.

So nuclear fuel continues to become less and less dangerous as it sits there contained and the real issue is just containing it for that initial period to prevent, you know, potentially dangerous exposure. And that tapers off relatively quickly.

Al

I wanted to address that because obviously, this is something that everyone worries about. This is a meme in the mind of the public that waste is an unsolved issue. That it’s some problem that nuclear has hazardous waste streams that get better over time, as opposed to other power sources that have hazardous waste streams that are hazardous forever.

Chris

Absolutely

Arsenic

Tom

for that matter, fossil fuel emissions, if you compact them and store them like you do the spent nuclear fuel, pretty toxic stuff.

Al

And it’s true. They don’t seem as bad because they’re not being captured and stored. They’re being spread into the environment.

Tom

That’s right.

Chris

Now, there are strict limits placed on Darlington, Bruce Pickering, any nuclear facility in Canada is highly regulated and monitored by the CNSC.

 They’re constantly checking to make sure that these companies are, you know, following regulations, and that the amount of emissions are within spec, but that doesn’t happen with coal plants, they just pollute with impunity. And some of those emissions are radioactive.

 Where are they going? Well, right up into the atmosphere.

Al

Indeed. So let’s talk a little bit about the history of CANDUs in Canada. You’re talking about Pickering, Darlington and Bruce, which are kind of the three main Ontario plants. What How did CANDU reactors get started? When did this process start?

Chris

1950’s. We started with Well, we had a couple of experimental reactors, but then we had the NPD, which is nuclear power demonstration reactor, which was constructed at Chalk River. And that was kind of a proof of concept for being able to produce electricity using natural uranium. From that came Douglas Point, which is the first large scale commercial nuclear reactor in Canada. And it was 200 220 Megawatt E. And it’s built, it still sits the site where we now have Bruce. Douglas point went critical ‘66. Tom, correct me if I’m wrong on that one.

Al

It went critical.

Chris

Yeah, it was producing electricity, mid 60s.

Al

A lot of people hear the term ‘went critical’, and they think it exploded. So, I just want to clarify the terminology, you’re going critical in a nuclear reactor is a good thing.

Chris

Yes, you’ve sustained a chain reaction, you. So that was point produced electricity. A significant amount, you know, a couple 100 megawatts. And you know, if you look back at some of our old hydroelectric stuff, for example, like we’ve had three or four generating stations at Niagara Falls, none of them were the size of Beck 2 like, these were all 100 200-megawatt max. So, you know, in that context Douglas Point, a single CANDU producing 200 megawatts was pretty impressive.

AL

How much power do we get from Niagara falls?

Chris

Beck 2 I think, is 1.6 GigaWatt, Right?

Tom

It’s around 1600. yes, 16 to 1700. And then the Beck one plant has been upgraded to the point where right now it’s probably around 350 megawatts.

And there’s a couple of units yet to come back on. So around 400 there, so roughly 2000 megawatts, but you got to remember the history back. Back in the 60s, the units were smaller.

You go with the fossil plants, the first coal plant in Windsor, the Keith Generating Station. Those units were 84 megawatts.

And then the Hern plant was built in Toronto in the early 50s. And the first four units were 100 megawatt units and the last four were 200 megawatt units. And then Lakeview was built in the early 60s, and they were 300 megawatt units.

So you know, it wasn’t out of line for the Douglas Point plant to be in that range, right.

 So it was 220 megawatts. So and that falls in line with the grid capability and the way the system gets built up, so

Chris

So AECL and Ontario Hydro got into some chats, after Douglas Point became a success. And that created the foundation for Pickering.

Okay. So Pickering was a partnership between the government of Ontario, the Canadian government, AECL and Ontario Hydro.

And the agreement was the Pickering would pay for itself within 15 years.

Al

Okay. that seems good.

Chris

So, Pickering was the first multi unit nuclear plant. They built the four Pickering A units, which were an incredible success.

 Construction started in 1966. First power was produced in 70 I believe. Yeah. 70, 71. Yeah. Incredible success. So from that, you know, people often refer to Pickering as the oldest new plant.

 Technically the A units are because at this point Douglas Point isn’t operating anymore, however, after Pickering A we did not build Pickering B okay. What came after Pickering A was Bruce A. So that’s one of those things where ‘Ah, Pickering’s old, we need to shut it down’. And then you’ve got Bruce, that’s going to continue running for another 30-40 years.

So anywayss, so we built Bruce A, and that was Ontario Hydro, and it started to take more control. At the time, the capacity factor I think, for Pickering was supposed to be 60-65%. That right?

Tom

That’s about the range they ran. And yeah, they were actually expecting higher when you look at the projections for the life of a CANDU reactor based on the effect of full power hours for the pressure tube life aging.

They actually were based on 80%. But realistically, they ended up doing in the mid 60s to low 70s

Chris

I think it was an economic target, I think was 65. Somewhere in that range. So Ontario Hydro took more interest in sort of steering these nuclear projects.

And so we ended up with this larger 480 fuel channel design and Ontario Hydro had this interest in making these four packs, which is why Pickering A is four units.

 And then Bruce A was four units. Okay. I think that was based on what we were doing with the coal plants at the same time and look at Nanticoke multi-unit plant it was very efficient.

Taking that process, you have a common turbine hall and you have units on the on the backside of it. So in terms of efficiency, it was a good move.

 So we built Bruce A and was everything was just bigger.

 So more fuel channels. The Bruce A units were oversized on the steam side, because they had plans of using process steam to run things on the site. Construction, they started working on a heavy water plant the CANDU six design was sort of coming to fruition around that point. And the point with the idea was to export.

 Okay, so if you’re going to be exporting CANDUs, you’re going to need to be exporting heavy water.

Tom

Ontario Hydro had to produce your own heavy water to begin with. The heavy water plant was actually running before Bruce A started up. There was an oil-fired plant that produced the steam for the heavy water plant and it was there.

 It operated till the mid 90s Really and the stack on that facility was just demolished a few years ago, maybe 10 years ago or something like that.

When you look at the older pictures of the Bruce site in the middle of it, the heavy water plant was you can see a tall stack and that was an oil-fired boiler.

Okay, and they actually used it for peaking too. The Bruce A units were running reduced, to supply the steam to the heavy water plant. And when you got to the high load conditions where you needed extra energy, they’d actually fire it up and displace the steam back into the Bruce A units for electrical output. Okay,

Chris

Yeah so that is process steam, but there are these plans for process steam including running this heavy water plant. That’s what we ended up they got the CANDU six design was starting to be matured and for export.

And so the idea of having all this heavy water was that we’d be able to export heavy water along with the designs themselves because you know we had to create that capacity here are our own units. So other places are clearly not going to have that capability.

 So that was a selling feature. Hmm. So then Pickering B started being instructed and the decision was made even though CANDU six was mature the decision was made to make it the same as the A units.

 So the units had 12 boilers. Okay, a lot of boilers. The Bruce units have 8 larger boilers, but it has fewer so but the decision with Pickering B was to make it structurally like Pickering A.

 So the unit’s all got 12 boilers, they have the same concrete domed containment structures. It looks very much essentially a mirror image of Pickering A, like conceptually, they’re more similar construction wise to a CANDU 6 but from a power generation standpoint they’re more like the A units.

Al

You’re talking about concrete containment structures. Have the CANDUs always had the concrete containment structures or is this something that came after the Chernobyl disaster? like people…

Chris

Even Douglas Point had a concrete containment structure.

Al

So we’ve always had this containment structure in place in the CANDUs

Chris

Yep. NPD had containment, the unit before NPD did not or didn’t have proper behavior. And we had a little bit of an incident at Chalk River and that was very much highlighted that there needed to be a safety needed to be the absolute utmost priority in case you have an event.

 So NPD had containment, Douglas Point had containment. The domes at Pickering are a metre thick, and they are lined with two or four inches of steel. Wow. So they’re quite impressive structures.

Tom

The thing that’s different now with the four packs, in the case of Pickering the eight packs was the vacuum building was added on for extra protection there.

Al

So what’s the vacuum building?

Tom

That’s what the standalone units don’t have. It’s when you look at the pictures of the sites for instance, Bruce A and Bruce B are separate plants, so they have their own vacuum buildings.

So does Darlington. Pickering, the eight units share one, of course two of them are in safe store They’ve been shut down for a couple of decades now. But it’s always got a vacuum drawn on it.

 And wha’s that in place for is if you have an event on a unit where the pressure increases, it’s inside its reactor containment, the vacuum building will actually suck out the pressure and it’s got a dousing tank and that to you know, cool down the steam or contaminants that are coming into it.

And of course, if that operates then the site will actually have to shut down because then the vacuum building is no longer protecting the other units but it’s an extra line of protection that these

Chris

Yeah, and the reason for that was because Pickering was being built adjacent to a population center. So, you had to have this extra amount of safety. I see.

So they built this very novel approach you know use this negative pressure containment structure that sits adjacent to the units themselves and is piped into all of the containment structures. It also has a massive as Tom mentioned the dousing tank it has a massive swimming pool at the top of it essentially, it’s full of water which can be used for dousing but it can also be used for makeup water so if you were to have a leak and you needed water there’s an obscene amount of it at the top of that back end building and it’s plugged into all of the units

Al

I see so this is to cool the reactors in the case you lose the power or you lose circulation from some other disaster that like the Fukushima thing you know if power is out from the main grid you can pipe this water in to cool the reactors.

Chris

Yeah, say that’s one of the there’s an obscene amount of it but you’ve touched on an important thing so all the CANDUsnare designed to be passively cooled.

Al

What does that mean?

Chris

So even if everything went black, you flood the steam generators and the units will just use convection and cool themselves.

Al

Okay, that’s interesting.

Chris

All of the control rods are gravity operated and as well as there’re the poisons that kill the units. So if a unit went blank <claps> or it went black rather,  it would poison itself, control rods would drop in, so it would put it in the lowest possible reactivity state, and if you had zero power if you couldn’t run any of the emergency pumps if all of the backup generators died you know think worst possible scenario you still have a massive gravity fed pool of makeup water in the top of the vacuum building but you also have the ability to just flood all the steam generators and use convection to cool the units

Tom

What they use for the CANDU units now is they’ve developed the safety systems and enhance the safety systems you know, everything is constantly changing and being updated, you know, the old analog stuff that was there in the 70s and 80s has been replaced with state of the art digital controls duplicated or triplicated and so on.

The other big difference of both the newer plants versus the Pickering A plant is the Pickering A plant was based on the Douglas Point design.  So the calandria itself sits dry. Those units had a dump tank in there. When we’re talking about the nuclear chain reaction, the one safety system for the Pickering A units would just dump the moderator [heavy water] into a tank underneath the calandria.

Chris

The ‘Core Catcher’

Tom

Yeah, and that would stop the reaction. The only problem is it took about 10 seconds to do it, which was considered too slow. So, Pickering A only had one fast acting safety system. When they returned from their outage in the late 90’s that one safety system was split into two so they’re not quite independent. But they do have two control rod drop schemes in there. But in the newer reactors the calandria is filled in a light water vault, so it’s filled up with water all around the calandrias.

So they even have that, that everything sits in a big pool of light water.

Chris

And a CANDU can’t sustain fission in light water. That’s another important point there. Okay. So if things do rupture. You lose your heavy water moderator. You cannot sustain fission.

Al

Okay. One thing I had heard, when I did my interview with Ed Lyman,  he said that CANDU is no good, because they have a positive void coefficient, or they’re not safe, because they have this positive void coefficient, you know what that means?

Chris

I do. It’s very, very, very slight. It just means that reactivity increases rather than decreases in the event of a noverheat condition, essentially, but that’s why they’re all the schemes that Tom just touched on all these additional mitigation mechanisms.

So for example, the reason that the fuel channels are oriented horizontally is because in the event that you had an overheat, situation did lose all of your water, those channels would deflect and it kills the unit. If they aren’t straight, kills the unit.

Okay, so there are all these sort of inherent safety features to prevent any sort of atastrophic event, you know, the double layers of water.

 And that’s your biggest risk is loss of cooling. And we’ve got that covered in spades. So the positive void coefficient doesn’t really apply in this case,

Al

because you’d never get there.

Tom

Not really, they like to talk about it, because that was also the RBMK reactors, right? Chernobyl, which had its little overheat issue and the hydrogen explosion or water explosion, right

So they always like to tie that to it and say, oh, yeah, it’s got a positive void coefficient, but I mean, they they’re totally safe.

Al

Okay. So we got to Pickering A and Pickering B. When did Pickering B come online?

Chris

Mid ‘80s ‘86?

Tom

Bruce B and Pickering B actually overlapped. The last Pickering Bs were coming on when the first Bruce Bs were coming on. So they actually overlap,

Chris

And then was Darlington which was the unit that was impacted by Chernobyl. There was a big pause, placed on the construction of Darlington, because of what had happened in the Ukraine.

And it was basically, despite there being no similarities whatsoever between the design our design and the Soviet design, we had to prove it couldn’t happen.

And until that, was proven, construction was halted. So Darlington took about 10 years. If you think back to how quick the other units were coming online, and then Darlington was 10 years. Wow. Okay,

Tom

There was a bunch of things going on there was the nuclear plants were coming on. For instance, the Keith plant was retired, the Hern plant was retired.

 So they were actually already getting coal off the system with these units. And then there was a recession in the early ‘80s 83-84, where demand dropped, and besides the Chernobyl thing, you know, the government says, we don’t really need Darlington, you know, maybe we should just cancel it, you know, and it was well underway at the time, and then the Liberals came into power and they wanted to cancel it, and then they decided, no, we’ll continue working on it, but we’ll slow down the construction of it.

So they actually stretched it out.

Al

No, that’s not good for cost, is it?

Tom

No. And so it  took a much longer time to do it, but even the guys I worked with, they said ‘oh, we shouldn’t be building Darlington we got Lennox in there, we could burn oil there for 30 years for cheaper than building Darlington’.

So you know, that kind of mindset was in there, ‘oh, oil is oil is cheaper, we can burn that and not build the nuclear plant. Right.’

Al

Gawd, So Darlington took 10 years. When did that come online?

Tom

The first nit started commissioning in 91. And about three months into the commissioning they found rotor cracks on it. I think it was number one that was first it might have been number two that was first.

But anyway, what they ended up doing was stealing the rotor from the G four unit to put in there to carry on commissioning.

And then they were starting to get fuel bundle cracking, and they tracked that down to vibrations in the heat transport system. It’s basically bouncing the bundles, and they were cracking. And it took them a while to figure that out. And they determined that the heat transport impellers were introducing a frequency into the system, I think it was 150 Hertz, that was a resonant frequency for the bundles and causing them to bounce.

So they actually had to change the impeller design, they changed the number of blades on the impeller to push the frequency up to into the 200 Hertz range or something like that.

And that fixed the problem. But you know, it was nothing they could do at the time, it was the first design of this type of heat transport system.

Darlington has a dual loop that has two independent loops, whereas all the other units have a single loop. So that’s the first time it happened. Of course now when anybody designs a plant now they look for this thing, but Darlington was the first plant that encountered it. So that delayed commissioning for a couple of years there.

And if you look at the in-service dates between a couple of units, that’s why they’re so close because the one was almost ready to be declared in service, then they had to stop commissioning and sit there idle for about a year, year and a half.

AL

So let’s talk economics here. Pickering was supposed to pay itself off in 15 years did that happen?

Chris

Pickering’s the only one that did though. Pickering was quite cheap compared to the subsequent plants. There were some design changes, Tom just touched on one of them with the dual loop cooling.

So as you progress, you have fewer and fewer steam generators or boilers. So, Pickering has 12 per unit. Bruce has eight. Darlington has four.

 Okay. So Darlington has two loops, and two steam generators per loop. Bruce’s just as Tom said one big loop. And that actually created an issue for the site back in the ‘90s. Bruce has the highest thermal capacity of any units in our fleet.

They’re actually higher than Darlington because they have more bundles. So same number of fuel channels, but 13 versus 12 bundles. Okay. There was a risk, potential risk identified that if the units were running at 100%, full power, and they had a loss of cooling incident, that potentially it would be too slow to react to that. And you could have an issue.

Okay. So you couldn’t shut down the unit fast enough before damaging anything. I see. So, you risk damage to the core before it would be sufficiently shut down, running at 100% full power, so they derated the units considerably. And then they had to employ some mitigation mechanisms, revise the end fittings, I think they looked at changing the coolant flow.

And ultimately, tin increments allowed them to eventually get up to 95% full power. Okay, which is where they operate right now. Okay, so Tom shared an amazing video on YouTube. Back in the day when he was in control room era, and you could see the Bruce units producing 860 megawatts, the Bruce B units

Al

Each of four. Yeah.

Tom

And the Bruce A units down to five and 600 supplying steam

Chris

If you look at the Bruce B units right now they’re producing around a 820.

Al

Okay, because of the derating, ,

Chris

And they were producing 860 yes, because of the derate. So that’s been an issue that, I wouldn’t say plagued but has hindered the plant for the last 20 some years.

It’s basically I wouldn’t say it’s been kneecapped but it’s a performance impediment. So one of the things that they have been working on as part of their MCR which is their major component replacement refurbishment plan is a way to get around that.

 And I don’t know if they’re looking at changing the cooling direction flow of making it two loop or not, I honestly don’t know. They’re replacing all of the boilers [at Bruce] all of them, Yep. They have all the boilers on site as they’re replacing all those. I don’t know if they’re also looking at making changes to the cooling system while they’re changing out the boilers. If they were that would be the time to do it when you’re replacing them all anyways.

 But regardless that I know that they’re also working with Cameco on modified fuel bundle designs. But anyways, there have been various attempts to try to improve the performance of Bruce to get back to where it was supposed to be. But as part of this MCR, which is more involved than the refurbishment at Darlington, because they’re also doing boilers and they’re also doing up-rates. They’re doing steam side and generator side tweaks to the units to increase output, which is quite obvious.

So if you look, you know, the A units were originally 750 megawatts 750 E, right? And then they also produce process heat. Unit One, A-one is now producing 816. And that’s still on a 5% derate.

AL

Wow. Okay, so we’re getting we’re tweaking these things to get 10s of megawatts extra, just by tweaking the design?

Chris

Yeah, absolutely. So the plan right now is to get rid of the derate entirely as part of the MCR. And they’re very, I would say, I would use the word confident. They’re incredibly confident about being able to achieve that. I don’t know if you saw the recent announcement, but 7000 megawatts and beyond.

Al

So that dwarfs Niagara Falls, right? That’s

Chris

Oh, God yeah. Bruce runs close to 90% capacity factor. So Darlington’s a little better. But they run very high capacity factor. And with the increased electrical output. It’s by huge margin, the largest generator in the province. So if you look at some of the pictures from the recent MCR, you’ll notice the units, the B units, say 880 on the side of them now.

Al

ah okay, okay, so Wow.

Chris

They’re very confident

Al

So let’s get back to the economics here so obviously, there was a lot of redesign early on in the 80s and 90s.

 I remember, you know, when they privatized Ontario Hydro, there was this stranded debt of billions of dollars related to building all of these nuclear plants that they didn’t think would ever get paid off. And we’ve been paying this debt repayment charge in our hydro bills for some time now.

So is it all paid off? Are the nuclear plants paying for themselves?

Chris

So 80s and 90s, when we were building all these things, Ontario Hydro was carrying the debt from those but it was also carrying the debt of other generating assets It’s not exclusively from the nuclear plants. Okay. Ah, Bruce B cost  something like 6 billion. It wasn’t super expensive. The only one that went way over budget was Darlington, it was 14.3 billion.

Tom

And that’s because construction was slowed down. You got to remember at the time, the interest rates were nuts, too. It was all financed debt at those interest rates. [Oh God yes] They were in the teens and they peaked in the low 20s. It was absolutely absurd at the time.

Chris

Pickering A was like 1.8. Like it wasn’t super expensive. Pickering B was like 2.8. Just pulling those numbers out of my, my posterior.  I remember the Pickering plants were not overly expensive. And Bruce A wasn’t really super expensive, either. Bruce B was  a bit more. The Darlington was the one where things just went sideways. And it was, you know, this combination of high interest rates, Chernobyl putting a pause on the industry, the issues that Tom mentioned.

You have to realize that, So Pickering was kind of blown up into Bruce A, right? This design, we’re going to make it bigger. And they did. So that fewer boilers, but same basic concept.

And the idea was that we Yes, we were working on this export model the CANDU six, which was designed to be a standalone export capable plant, but at the same time, okay, well, we’ve got these bigger units, ‘we can export them too!’ So that created the foundation for the CANDU 900 / CANDU 9, which was an export version of a 480 fuel-channel design. Okay, so it’s like a big, big brother of the CANDU 6. And the CANDU 9, like, with Pickering, A and B, were basically a development hotbed for building the CANDU 6, right, like the CANDU 6 is what distilled out of that construction process.

And in the same way, that’s how the CANDU 9 happened is that you know, you took the Bruce A. Bruce A is an interesting case study in itself. I don’t want to get into that too far. But there are some differences between each of the Bruce A units, as they were kind of trying to figure out what they were doing well,

Tom

actually, there’s differences in all the units except maybe Darlington,

 As they go along, as they were building the units, that the engineers at hydro like to tinker and tweak, right, that’s why they wanted more control over these things. And I think AECL was much the same way.

 And as you’re building the units, you know, they’re supposed to be identical, and ‘hey, this works better, you know, we can run this pipe this way, rather than that way, or have this thing you know, connected to this rather than that or protect this this way rather than that way.’

So they, every unit actually has differences. And it’s like that with all of them. In fact, when they built the CANDUs for Korea, Korea insisted that all the units be identical. [That was a good decision] They didn’t want any updates or tweets or any thing. They wanted them identical.

Al

So these plants are all being refurbished right now the Bruce and Darlington are being refurbished. How many years do they have left in them after these refurbishments?

Chris

Well, so that gets us into the whole look at Pickering situation.

 So we’ve already done Pickering 1 and 4, but we didn’t do the boilers. Okay. And we already did Bruce one and two, but we did do the boilers. That’s the again, it gets back to that confidence that Bruce Power has, they’ve already done full boiiler replacement on two units. They know what they’re getting into.

Tom

But what you can do Al is look at the Pickering B units, which you’re pushing 40 years now. And so are the Bruce B units you know, same thing.

So the original 30 year estimate for life has already increased by 10 years. And it can probably go further. Although there have been some issues that came into play here the last few months about the hydrogen accumulation in certain portions of the tube.

But you know, they’ve increased the effective full power hours on the tubes, the original design was 210,000 hours.

And the Pickering as is allowed to go to 295,000. The Bruce units say they’re good for 300,000. Okay, so that pushes them up to 40 years plus. So when you get after refurbishment the life of those, you’re gonna nominally probably look at maybe 30 or 35 years, but you’re probably going to get 40 or more years out of them yet,

Chris

And that and that’s consistent with what Bruce Power’s anticipated life is.

Tom

And that’ll be based on the actual hydrogen pickup that they’re detecting in the tubes, they do modeling. But then as the unit ages, they’re checking the hydrogen accumulation and the tubes and they can estimate, ‘oh, we can extend this further’ type of thing.

Al

And looking at the economics of this. So, Bruce Power is actually a commercial operator, this is not provincially run at all. This is divested to a commercial group, and they are providing power at a fixed rate, which includes all the money that they’re spending for these upgrades, is that correct? [Yep, That’s correct] How much is it?

Tom

There was just an interesting Twitter exchange, where one person online, a lawyer actually said, ‘oh, you know, they’re being subsidized by OPG, the rate you’re seeing for Bruce Power is not the real true rate.’ And Bruce Power piped up and says, ‘No, it is’ and they quoted, I believe, 8.1 cents per kilowatt hour. All-in. And that’s the refurbishment, everything

AL

that’s below the average

Chris

Oh yeah, significantly below the average. How that was negotiated was Bruce was originally on a 6.4 or 6.6 cent rate, fixed rate, with the province.

And then they have this massive $13 billion MCR project.

So the agreement was that once that was underway, that price would increase to 7.7 cents. Okay, which could then be adjusted for inflation. I see. And we are at the adjusted for inflation bit right now.

That’s why we’re at 8.1, as there’s been some minor tweaking to that rate. It was 7.8-7.4, I think last year, and right now we’re at 8.1.

AL

Does this also include decommissioning and fuel storage?

Chris

Yes. There was $20 billion in two funds that are managed by the Ontario government. Right now, the majority of that is for decommissioning. And there’s about 5 billion of it that’s set aside for spent fuel management.

Al

And that’s taken out of the price that we have right now that we’re paying which is below the average.

Chris

Correct. Yeah. That includes both of those funds, it includes the entire cost of their refurbishment. Everything. The works.

Tom

Just circling back to the stranded debt. You know, the numbers we’re talking about here for the Green Energy Act and paying these people not to produce and so on is so much higher than what that stranded debt was and the stranded debt came out of the fact that they split up Ontario Hydro into five companies.

And a good chunk of that stranded debt was the extra cost that was there for Darlington. So OPG being a smaller company than Ontario Hydro was because all they were was a generation company.

There were a few other factors that went into it too. The stranded that was put into the Ontario Finance Corporation. They had a line on the electricity bills, it was point nine cents a kilowatt hour that we have to pay and it was supposed to be paid off in 12 years. So basically 2011. And the thing never got paid down at the rate that it was supposed to get paid down at. And quite frankly, I personally think people were playing with those funds and hiding expenses in there for other things because it just kept stretching further and further and further, and I believe it was there until Doug Ford said ‘enough of this. It’s going on the government’s books now.’ And there wasn’t that much less. But it was supposed to be paid off in 2011. But somebody was playing with the thing and it was never being paid off. So, it wasn’t a huge amount. It didn’t really make Ontario Hydro insolvent.

It was just there was a chunk of debt that they really couldn’t put on any of the successor companies that they had to deal with set

Al

well, they’re basically using it to subsidize the renewable energy feed in tariffs of what you say? Almost 15 cents a kilowatt hour for wind and 49 cents a kilowatt hour.

Tom

At the time they were big on conservation too

Chris

So, when I first started paying electricity in Ontario, I was paying four point 4.4; 4.6 cents a kilowatt hour flat out.

Al

And now we’re soaking up debt to adjust the price of the renewables. Yes, but let’s move on. We’re getting towards the end of our time. I just want to touch on the Pickering refurbishment idea that’s been floated.

 So we know that the Bruce is being refurbished the Darlington’s being refurbished and the Pickering is not being refurbished. And they’re saying from what I hear the justification is they don’t think it’s as economical as the other two refurbishments.

What are the economics of refurbishing Pickering? And when why is this a problem?

Chris

So the Pickering refurbishment was approved by the Canadian Nuclear Safey Commission. Let’s get that out of the way first. OPG already had a plan for the refurbishment.

They submitted to the CNSC. The CNSC approved the plan. And then we had the gong show with the Green Energy Act that we just touched on.

We also had OPG wanting to build Darlington B. And then we also had the impending approval for the refurbishment of Darlington A.

So you had all of these large projects that kind of wanted to be done at the same time around the same time. And we had a government that was not really interested in nuclear and it was like ‘we’re doing wind and solar privately’ and wasting 10s of billions of dollars that way.

 So, when the cost of the Darlington B project started to come up, OPG just abandoned the Pickering B refurbishment and focused on the Darlington refurbishment and wanted to see you know, if they abandon the Pickering refurbishment maybe they get to build Darlington B and then 2014 rolled around.

They abandoned that in 2011 I think it was right when the EA was approved for Darlington B. And then Kathleen Wynne cancelled Darlington B in 2014. So even after doing all of that, they still didn’t get to build it.

So there were, definitely some politics in play there as well. But there is an economic,. there is a valid economic critique for Pickering. The Pickering units are smaller.

That’s really what it comes down to. You have four units that need to be refurbished, and they are 516 megawatts each versus 878 for the Darlington units. If you look at the cost in terms of per megawatt, these units are going to be significantly more expensive to refurbish, because they don’t reuse as many watts, I see.

Tom

More parts, 12 steam generators, you know, the pumps and all that, a whole bunch of pumps. And it takes a few more staff to run them than the other units because they’re a little bit more complex. Right.

Al

So, what’s the upshot? We were looking at something like we were chatting about this before something like $9 billiion, 8.6 billion to refurbish Pickering?

Chris

If you look at the per unit cost for Bruce right so you’re replacing eight steam generators you’re doing all this other work that they’re doing at Bruce so replacing all 480 fuel channels and they’re doing these uprates and some additional tweaks, they’re upgrading control systems you know doing the majority of the same thing as we’d have to do at Pickering B.

Okay, so I take that per unit price and apply that to Pickering because the Pickering refurbishment is different from the Darlington refurbishment. The Darlington refurbishment is not getting the same stuff. Where the Bruce really is they’re very similar.

So Bruce benefits from OPG already paying the price to get the supply chain in motion, and, you know, The Bruce refurbishment is less per unit. But in terms of similarity, it’s very similar.

 So, the idea we has to tack the Pickering refurbishment onto the end of the Darlington refurbishment, so you’re again capitalizing it from that momentum, you’re capitalizing from those supply chains, because they all take the same bloody parts for the most part, like they’re very similar. In terms of components, they all have pressure tubes

Al

the same expertise as well.

Chris

Exactly, for all CANDUs. So, BWXT would produce the boilers just like they did for Bruce. And so that per unit price ended up with the exact figure was 8.7 billion. So we fudged it and said maybe 9.

Tom

The schedule, we’re sort of evaluating, like Christopher said, dovetails into Darlington, and basically dovetails the workforce into that too. They move over from Darlington over to Pickering. And that’s continuity for the workforce, the expertise the supply chain etc., etc. Right.

Al

So that produces as much power as in a year, I think, in 2019 Pickering produced 24 terawatt hours, our entire Ontario wind fleet produced 11.7 terawatt hours that same year, so this is twice the annual output of our entire wind fleet for the next 30 to 40 years for $8 billion.

Tom

What do you have to look at though, is but what you get out of the refurbishment of the four units, which is the 8 billion dollars, is you get to continue operating units, 1 and 4 at Pickering A for the balance of their life, [which we’ve already paid for]

Yeah, so that’s where the 24-terawatt hours comes from. And you know, that part of that is the A units, which you’re hanging on to that are really not part of the refurbishment, but they do provide you that bonus.

Chris

You can do this as many times as you want. Like the calandria doesn’t wear there’s no wear component to the calandria. It’s not pressurized, it just sits there. It’s a giant vat of water.

 So you can swap out those pressure tubes as many times as you want to. It’s the rest of the plant that you’re concerned about at that point

Al

Interesting. Well, this is this is a good plan. I think. So, this seems very doable. It seems very achievable. It seems economical. Maybe we should throw in a Darlington B as well, while we’re doing this.

Chris

Well. I do want to mention one point you brought up the annual output. But that doesn’t tell the story. And the reason for that is that Pickering out produces our 5000-megawatt wind fleet by five times during the summer,

Al

during the summer when we need the power the most.

Chris

Yes, so Ontario is Summer and Winter peaking our winter peak is a little less than our summer peak. But our peak demand period is those summer months, and that’s when our wind farms produce the least amount of power. And during those summer months, when we are running air conditioning, we’re you know, trying to keep our seniors cool [very good point] all those important things

 Pickering is out-producing that wind fleet by fivefold. And that’s not captured at those annual figures.

Al

So this has been a great discussion, guys. I really appreciate you guys coming on in and helping me in understand where we’re at. And hopefully, everybody has learned a little bit about our CANDU fleet just as we say 60% of Ontario’s electricity is being produced by our CANDU reactors.

And let’s keep that going. Keep the momentum thanks for all your good work and with Canadians for nuclear energy. And thanks for coming on the podcast. I’ll send you guys some Rational View T shirts for coming on with me. And you can enjoy those and show up show off the podcast to all your all your buddies.

Chris

Thank you very much for having us.

Tom

Pleasure being here.

Al

If you’d like to follow up with more in-depth discussions, please come find us on Facebook at the rational view and join our discussion group. If you like what you’re hearing, please consider visiting my Patron page at Patron.podbean.com/therationalview thanks for listening

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