Too hot for Nuclear?

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This is from Vox:
"Across the channel, France broke more than 100 all-time heat records across the country in the past week. But just as energy demand is spiking with people desperate to cool off, the high temperatures have forced France to cut down its nuclear power output since the rivers used to cool the power plants have become too hot. Much of Europe is already dealing with a spike in energy prices after Russia’s invasion of Ukraine led countries to reduce their use of Russian oil and gas."

I wonder how many of the world's nukes rely on river water for cooling?
 
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CT's Millstone which is on Long Island Sound has had this problem; LI Sound is "the ocean" but somewhat of a captive part of it.

Might exceed the design criteria of the plant, also may increase corrosion rates etc etc.
 
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Speaking from thermal plant, and coal or nukes are big kettles. They run on the rankine cycle, and the ranmkine cycle energy available, and efficiency are determined by the upper an lower temperature bounds of operation.

With a cooling tower, the upper temperature is fixed, and it all plays on the lower...on a hot humid day, tower water temperature rises, lifting the bottom stop, and the condenser vacuum falls (higher absolute condenser pressure), limiting load, and reducing efficiency...the vaccuum unloader pulls MW out of the system.

As others have mentioned, those that use either coastal or river water bodies to dissipate heat often have to limit the temperature rise, or absolute water body temperture.

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I'm sure there are technical reasons such as shown above, but also in my area they do not want to raise the temperature of the water in the Chesapeake Bay. Thus cooling towers before the water is disposed into the Susquehanna river.
 

JTK

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Our cryogenic air sep and hydrochem plants use Niagara river water for the majority of our cooling needs. It's tough to keep equipment cool once river water temps approach 80F in the heat of the summer, which it does nearly every summer.

We can't return the water more than 10degF warmer than what the supply temp is. We draw such a volume that I've never seen that come into play.

Regardless of what cooling system you have, closed loop towers or a natural water source, it's problematic. Nothin' easy.
 

OVERKILL

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This is from Vox:
"Across the channel, France broke more than 100 all-time heat records across the country in the past week. But just as energy demand is spiking with people desperate to cool off, the high temperatures have forced France to cut down its nuclear power output since the rivers used to cool the power plants have become too hot. Much of Europe is already dealing with a spike in energy prices after Russia’s invasion of Ukraine led countries to reduce their use of Russian oil and gas."

I wonder how many of the world's nukes rely on river water for cooling?
A lot of the French units are once-through, which means no cooling towers, so they are more prone to being impacted by regulation that limits discharge temperatures. Typically, if the body of water is relatively small, like a river, cooling towers are employed because this eliminates that issue. However, that clearly wasn't factored in with some of the French plants (and plants elsewhere for that matter).

To give you an idea of the magnitude here, Bruce Nuclear here in Ontario, which is the largest operating plant in North America, and 2nd largest in the world now, has 8 units and employs once-through cooling as well, but its water source is Lake Huron, which of course is massive. It never has any thermal constraints put on it. Typical temp rise is 3C, but the limit is 10C.

Darlington and Pickering, which are both on the much narrower Lake Ontario (a lake which does tend to warm if we get some sustained heat) have the same limits, and the cooling inlet/outlet differential would be the same. I don't recall Pickering ever getting its output reduced and it draws in the front and pushes out off the sides. Darlington draws in from the bottom of the lake about 1Km out, and outlets the same way, but on a large angle. It does periodically get thermally constrained, I assume due to the location of the inlet and outlet diffuser, there may be a bit of a natural rise there that creates a pre-existing differential of sorts?

When these plants are thermally constrained that are NOT shut down. Their output is simply reduced; their thermal capacity is dropped down a bit. Darlington units are nominally around 880MW, but we'll see them down around 820-840 when constrained.
 
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It has to be for environmental reasons. The way nuclear power works is that the nuclear fuel boils water. The boiling water is turned to steam, the steam turns a turbine which generates electricity. The water temperature in the intake shouldn't matter because this water is going to be boiled inside the plant.
 

OVERKILL

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It has to be for environmental reasons. The way nuclear power works is that the nuclear fuel boils water. The boiling water is turned to steam, the steam turns a turbine which generates electricity. The water temperature in the intake shouldn't matter because this water is going to be boiled inside the plant.
The water that comes in from the lake is never boiled.
 
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The water in the steam cycle is never run over stream, not tap water, has to be demineralised, and treated with at least, ammonia and or hydrozine or equivalent...it's ultra pure, and condensed and returned to the steam cycle. (just for comparison, that flow rate is approximately the evaporation from a cooling tower (if fitted).
 

OVERKILL

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In a pressurized water reactor you're right. I work at a boiling water reactor and the plant service water is definitely is boiled.
There are multiple loops within any thermal plant (which Shannow touched-on).

With a BWR you only have one loop for coolant and running the turbine. The 2nd loop in this case is your condenser cooling water that takes the heat away from the reactor coolant water after it has gone through the turbine as steam.

With a PWR you have two primary loops with the core cooling water heating a 2nd loop of water in the boilers/steam generators, which in turn drives the turbines. In this case, the water that touches the fuel never touches the turbine. After going through the turbine, the steam condenses in the condenser, which, like with the BWR, has its own heat exchanger that uses the raw water source, be it a lake, river, cooling tower combo...etc.

The water that is used to cool the condenser is its own loop, and as I noted earlier, there's a temp rise limit on this, which, with once-through cooling, moves a LOT of water. Our limit here in Canada, IIRC, is 10C, but the plants are typically nowhere near that. That means if the inlet water is 8C the outlet water can't be any warmer than 18C. Problem is there's a lake water/river water limit as well and if you are already drawing in warm water, you can run into that limit before you run into your own rise limit. Say the lake is 15C, well, it's not reasonable to release 25C water say, maybe the lake discharge limit is 20C. So then you have to throttle thermal back so that your rise is only 5C (if you are above that).

Cooling towers solve this problem because they only draw a small fraction of the volume vs once-through from the source, which is evaporated, and it's the process of evaporation that provides the cooling.

Palo Verde uses waste water in its cooling towers, as it's located in a desert.
 
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We have the same issue in my town, cooling towers were put in about 10 years ago, but there can still be reduced output in summer.

Record rain levels at the moment, and the town is on water restrictions. We draw town water from the river, but with the rain silt levels are up, and the filters are blocking, needing cleaning, reducing the amount of water they can pump. It looks like I am running a bath of mud at the moment.
 
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down in the park
This is from Vox:
"Across the channel, France broke more than 100 all-time heat records across the country in the past week. But just as energy demand is spiking with people desperate to cool off, the high temperatures have forced France to cut down its nuclear power output since the rivers used to cool the power plants have become too hot. Much of Europe is already dealing with a spike in energy prices after Russia’s invasion of Ukraine led countries to reduce their use of Russian oil and gas."

I wonder how many of the world's nukes rely on river water for cooling?

too hot for the fauna and flora in the river they mean. the power plant will be just fine
 
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We have the same issue in my town, cooling towers were put in about 10 years ago, but there can still be reduced output in summer.

Record rain levels at the moment, and the town is on water restrictions. We draw town water from the river, but with the rain silt levels are up, and the filters are blocking, needing cleaning, reducing the amount of water they can pump. It looks like I am running a bath of mud at the moment.


I thought New Zealand was a nuclear free zone?

I collect rain water for showers and the like.
 
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