Ontario Nuclear Update - July, 2022

[OVERKILL]

Bringing this series back to life, Bruce Power has added capacity (uprates) to two units at the Bruce A plant.

Originally, the Bruce A units were oversized thermally for their expected electrical output because they produced process steam to run the adjacent sprawling heavy water plant, that was constructed due to the expected demand for deuterium corresponding with C6 and C9 foreign sales. Of course those sales never materialized once the pause from Chernobyl took hold and eventually the plant was dismantled.

As I've mentioned previously, the Bruce units have the highest thermal capacity of any in our fleet with 480 fuel channels with 13 bundles each. That's 480 more bundles than Darlington, the plant that currently houses our highest output units (~880MWe). The Bruce A units have the same thermal capacity as the Bruce B units, which were originally 860MWe before the whole site was derated in the 90's.

Bruce Power has been putting considerable effort into uprating these units and increasing output. Unit 1 seems to be the first to really reach its threshold, going from 768MWe to 816MWe now. Unit 2 appears to be joining it, it broke 800MWe today:

Unit 2 recently returned from a maintenance outage and I had (well-based) suspicions that uprate activity would be part of that outage, based on the success with Unit 1. Seems I was on the money.

Now, what do these uprates mean, contextually? Well, the site goal is 7,000MWe.

Currently, this is the status of the derates at the plant:

So:
- Bruce A is limited to 92.5% full power
- Bruce B is limited to 93.0% full power

So, these uprates are all based on thermal derate capacity.

Pretending for a minute we can just work the math backwards on the electrical output, 816MWe with the derate pulled is 882MWe. Multiply that by 4 and we've got a 3,528MWe station. Do the same with the B plant and you are easily past 7,000MWe, which I assume is why they are so confident on being able to achieve that goal, they know what the units can produce.

As you can see, Unit 6 is down for refurbishment. I'm hoping we get to see it run to 100% capacity upon its return. That will really tell us what things will look like. Bruce has been working with their fuel supplier, Cameco, on an updated fuel bundle design that should allow them to petition the CNSC to have the derate pulled. As you can tell, that will be a game-changer for the plant.

 

[Cdn17Sport6MT]

We need more of them... We need some focus, too, on small units in western Canada.

Unless and until we embrace nuclear, widespread electrification of transport sector is unachievable. I'm a "petrolhead" and I will cry when I'm forced to junk my ICE cars. I hope I never see the day... but I know I'll hafta buy a BEV at some point, sooner rather than later.

 

[Cujet]

Hey, that's pretty neat.

How many Tesla Semi's could this plant, at the current output, simultaneously charge, assuming each truck is using a "megacharger" at full capacity and taking into account grid losses?

 

[OVERKILL]

Hey, that's pretty neat.

How many Tesla Semi's could this plant, at the current output, simultaneously charge, assuming each truck is using a "megacharger" at full capacity and taking into account grid losses?

I assume this may be a little tongue-in-cheek but we don't know how much power the Tesla Megachargers actually draw, as they are just ">1MW" for output.

So, without more information I couldn't give you much of a decent WAG

 

[Al]

We need more nukes. Three Mile Island closed bc politicians had their hands in Natural Gas Producers' pockets. Sad.

 

[OVERKILL]

We need more nukes. Three Mile Island closed bc politicians had their hands in Natural Gas Producers' pockets. Sad.

Same with Indian Point.

 

[Dave Hess]

Nuclear is very safe **if** done correctly.

 

[Cujet]

I assume this may be a little tongue-in-cheek but we don't know how much power the Tesla Megachargers actually draw, as they are just ">1MW" for output.

So, without more information I couldn't give you much of a decent WAG

Well, it's was a bit of silliness, with a side of seriousness. I'm not at all sure what the actual draw is, but I can guess that it's higher than the 1 megawatt range. Other companies such as Daimler are shooting for the 3 megawatt range.

Considering just how many trucks will be charging at one time, and their comparatively short range, I suspect we could run some numbers and come up with a scary number.

 

[OVERKILL]

Well, it's was a bit of silliness, with a side of seriousness. I'm not at all sure what the actual draw is, but I can guess that it's higher than the 1 megawatt range. Other companies such as Daimler are shooting for the 3 megawatt range.

Considering just how many trucks will be charging at one time, and their comparatively short range, I suspect we could run some numbers and come up with a scary number.

We absolutely could! LOL!

 

[PandaBear]

Just wondering, when they uprate or increase power of a nuke, what is involved and how do they know they have enough safety margin? Is it usually an improvement in the pressure and temperature handling, or a better understanding of their failsafe mechanism to handle failures? or improved plumbing so the heat is transferred to the turbine faster and more efficiently? or just improved turbine efficiency?

 

[OVERKILL]

Just wondering, when they uprate or increase power of a nuke, what is involved and how do they know they have enough safety margin? Is it usually an improvement in the pressure and temperature handling, or a better understanding of their failsafe mechanism to handle failures? or improved plumbing so the heat is transferred to the turbine faster and more efficiently? or just improved turbine efficiency?

It depends on the plant.

The reason Bruce was derated was because of its coolant flow. It has a single loop, which means that in a snap LOCA, there's the potential for losing up to 50% of its cooling capacity, and, at its full thermal output level, this could allow for fuel damage before the FASS can shut the unit down. Darlington uses two loops, so its potential capacity loss is only 25%. Pickering has fewer bundles, channels and pins, so the same risk isn't there, it just doesn't have enough thermal capacity.

Bruce was originally derated to almost 50%. This was later scaled back a bit after some studies were done, and then later there were mitigation mechanisms implemented such as fuel against flow (which reduces localized flux increases IIRC) and the implementation of flow straighteners and spacers in the end fittings, which prevent bundle shift, and thus flux events (again, IIRC) in the event of a LOCA, which is what allowed the power levels to get bumped back up to where they are now.

So, all the current improvements/uprates we are seeing is with thermal power fixed at 92.5% of capacity on the A units and 93.0% capacity on the B units, no increase in thermal output has yet taken place. The plant is still running below design. I'm not sure what they are doing to try to get it to be able to run up to design capacity, if anything, beyond an improved bundle design. I suspect it's possible to implement 2-loop cooling during the refurbishment, but I have no idea if that's been even looked at let alone being pursued. Basically, they need to make it so that in a LOCA, like a full channel split, that there is sufficient margin to prevent any sort of fuel damage. If they can do that, and prove to the CNSC that this works, they'll be allowed to run up to 100%.

So, these uprates, what you are seeing is all on the turbine and generator side with thermal capacity limited to what we've already discussed. So, heat transport system, turbine improvements, rewinding of stators, better HP and LP turbines (upgraded blade designs)...etc. These A units were originally only designed to produce 750MWe, so there's obviously significantly more room for improvement on them than the B units, which were designed for 860 (remember, both sites have the same thermal capacity). The fact that they've got A1 up to 816 means that they've hit their target, so clearly whatever they planned has been a success.