The problem is they draw cool water upstream from the river and dump the warm water downstream. There's a limit to how much warm water you can dump because it raises the overall temperature of the water which impacts aquatic life.

Extreme heat and a severe drought do two bad things:

1. Lowers the river level. This threatens to expose the intake pipes drawing in cool water. Those pipes must remain submerged for their pumps to work. They don't rest on the riverbed because they don't want to draw silt from the bottom of the river.

2. Raises the temperature of the water. Lower water levels mean the river has less thermal mass and so the hotter air is warming up the water that much more. That means the cooling water is hotter. This typically isn't a problem as far as cooling the plant itself is concerned but consider that To - Ti (temperature of output - temperature of intake) is constant, so if Ti increases then To must also increase, which as already noted impacts aquatic life. The water may simply be too warm.

Either (1) or (2) is problematic - the two together are a big problem and threaten to shut down the plant. This doesn't just apply to nuclear power units either - coal units, IGCC units and HSRG units face the same issue as do nuclear units. You're right though, this is a big problem getting very little attention. This is one of many reasons why utilities are investing so much into solar and wind - no cooling required.

I'm not talking about dumping the warm water downstream, but using evaporative cooling as an alternative solution.

Cooling towers don't recirculate the drawn water back to the river as far as I'm aware. They only draw the water in the basin depletes. Looking at the sources, 2% of it is lost to evaporation, the rest condenses back on the bottom.

So it doesn't actually draw that much water, and it doesn't dump the warm water downstream.

90% humidity in Hamburg and similar throughout Germany as of writing this. Is it feasible to site plants on the ocean and upgrade HVDC to the interior of the continents?

Dry cooling towers exist. One could also have a look at https://en.wikipedia.org/wiki/Palo_Verde_Nuclear_Generating_... near Phoenix, AZ which for all practical purposes is a desert.

>The facility evaporates water from the treated sewage of several nearby municipalities to meet its cooling needs. Up to 26 billion US gallons (~100,000,000 m³) of treated water are evaporated each year.

I have no idea how that stacks up to other nuclear plants, but 100,000,000 m³/y sure sounds like it needs a lot of water.

More cooling towers would mean more water needed, since they rely on evaporating water. With river levels already low, I bet they're cautious about using more water.

I wonder if they're considering refrigeration, or if that's even feasible. Conceivably, you could use the power from the nuclear plant to cool itself, since refrigeration has a higher-than-1 coefficient of performance.

Refrigeration is pointless if your hot source is 100C. And you'll still need a new cold source to dump the heat into (and now there's 30% more).

You could recondense the steam by dumping the heat into the atmosphere, but that's bigger and more expensive.

You could also store it in thermochemical batteries and save it for winter. The logistics of moving 1t of NaOH every few seconds sound difficult.

You might be able to export it via steam pipe and charge thermochemical batteries on site. That requires logistics that don't exist.

It's not an issue of river water levels. It's an issue of permissible river temperatures. They should rethink the impact of heating a river versus increasing fossil fuel emissions that heat the whole world.

Cooling towers don't recirculate the drawn water back to the river as far as I'm aware. They only draw the water in the basin depletes. Looking at the sources, 2% of it is lost to evaporation, the rest condenses back on the bottom.

If they weren't recirculating water downstream the river wouldn't be heating up at all. In France it's due to limits on river temperature: https://www.reuters.com/business/energy/warming-rivers-threa...

Because apparently letting a river get above 28 degrees for a few kilometers is worth pumping more carbon dioxide into the air.

I wonder how the French got into that problem since nuclear power plants exist in tropical countries where the temperatures can get incredibly high.

It seems likely that they simply designed it for a max expected water temp and they're exceeding that max. If you need more water to cool the same amount, you're gonna need some bigger pipes.

It's not an issue of being unable to cool the plant, it's an issue of the plant being prohibited from heating up the river too much. Apparently this is done for ecological reasons, though seeing as it results in more fossil fuel emissions it might be better to hear the river.