Jan Wildeboer 😷Jun 29, 2025
Next week, France is forced yet again to reduce output and in some cases completely shut down nuclear reactors as the high temperatures heats up the cooling water they take from rivers beyond acceptable limits. This is the new normal now and will only get worse over the following years as we collectively ignore #ClimateChange
Show threadaeris
@jwildeboer And our Cour des Comptes said it only concern 1 to 2% of nuclear power.
In the same time, solar panel must be cooled with water to stay at 25°. Each ° above is 0.2% to 0.5% less power.
Jun 29, 2025 at 10:33amWeb
Show threadaerisJun 29, 2025
@jwildeboer And nuclear plant can work without open water source. We just built reactor near such source because it's easier. We can just cool plant with closed source, like Palo Verde, in California desert, which use waste water of the near city.
Show threadLukas GrossarJun 29, 2025
@aeris @jwildeboer The temperature coefficient also works the other way, every °C below 25 °C increases their efficiency by the same percentage. When I did the calculations for the power limits of my installation I had to calculate the "worst" case scenario with regards to the highest power output at -8 °C.
Show threadBreizhJun 29, 2025

@aeris @jwildeboer And it’s mostly for power plants without cooling tower.

Like in Bugey, where the two reactors without cooling towers will be replaced by new ones with cooling towers to fix the problem.

(And, if instead of directly reusing the output of cooling towers, you discharge it into the river, you can even cool the watercourse, as is done at Civaux on the Vienne)

Show threadTiber SeptJun 29, 2025

@[email protected] @jwildeboer So, I see this is relevant, but is it the most important aspect? According to your statement, at 50°C we'll have 13% less power from each panel max ... as compared to playing with the cooling system of nuclear reactors. I bet accidents never happened this way

UPDATE: I was arguing here against bots, I deleted all my follow-up posts as they were mostly to trick the bots to do basic calculations.

Show threadaerisJun 29, 2025
@tibersept @jwildeboer We don't play with the cooling system. We lower down 1 to 2% of power to avoid any damage to nature and plant.
Show threadaerisJun 29, 2025
@tibersept @jwildeboer And also please stop forget that solar plant are 5× deadly than nuclear one.
Show threadaerisJun 29, 2025
@tibersept @jwildeboer And don't forget too that scotish wind plant did more than 250 direct deaths in 20 years for not even one hundredth power production of Tchernobyl.
Show threadJobJun 29, 2025
@aeris @jwildeboer @tibersept what rabbit hole are you from?
Show threadtrusty falxter 🧠Jun 30, 2025

@aeris @jwildeboer @tibersept It was 1–2% on average AFAIR, that may sound low, but during short critical periods, this causes noticeable energy shortages in the grid. Temperature limits for rivers have even been raised to avoid shutdowns, showing the issue isn’t trivial.

Nuclear plants can be built without natural water sources using closed cooling or wastewater, but France didn’t do this because it’s more expensive and complex. Alternative cooling would increase costs and possibly water use.

Here, many solar parks and private systems exist, but none with water cooling. Especially with PV surplus, using water to improve efficiency makes little sense.

Show threadaerisJun 30, 2025
@jwildeboer @tibersept @flxtr No, it's not 1-2% on avg, but 1-2% maximum and in 2050.
Show threadtrusty falxter 🧠Jun 30, 2025
@aeris @jwildeboer @tibersept 2050? Don't think we are talking about the same thing.
Show threadBreizhJun 30, 2025

@flxtr @aeris @jwildeboer @tibersept Well, France did do it on a lot of reactors particulary on smaller rivers. On the big ones it wasn’t necessary, but now it is, so that’s why all new nuclear plants on rivers (not the ones on the ocean) will have closed cooling.

The fact that we can run nuclear power plants on smaller rivers is a proof that we can solve the problem on the bigger rivers by using the same technology, which gave a lot more margin (it do use a bit more water, but nothing dangerous for the river and its wildlife, since you’re not heating the watercourse).

Show threadBreizhJun 30, 2025

@tibersept @aeris @jwildeboer We’re not playing with it, we’re just lowering the heat output to avoid overheating the watercourse. We could continue to use it to max power without safety issue, but it could hurt the wildlife.

Do you know how a thermal (not only nuclear, but fossile ones too) electrical plant works?

Show threadaerisJun 30, 2025
@[email protected] @tibersept @jwildeboer And there is this trouble only on high temperature, which is basically on summer so also the least energy consumption point. And so the moment nuclear plant are stopped for refill. So usually not a trouble, we ALREADY have to stop ~30% of the park to go from 70GW on winter to 50GW on summer.
Show threadaerisJun 30, 2025
@[email protected] @tibersept @jwildeboer Fun fact too : it's less CO2 intensive to go on gaz backup (300g/kWh) for the 2% lower nuclear power (6g/kWh) for 50GW so 11g/kWh than producing 50GW from wind turbin (14g/kWh)
Show threadBreizhJun 30, 2025
@aeris @jwildeboer @tibersept (especially since wind turbins needs a lot more of backup in practice…)
Show threadaerisJun 30, 2025
@[email protected] @tibersept @jwildeboer And so, once again, the ONLY trouble with 1-2% lower nuclear power plant is where to produce those missing part. And this is NOT a trouble if we know in advance we will need such cut. This is called : planning.
You can produce that with another underpowered not overheating nuclear plant, with one planned for refill, or with any other production mean (gaz, wind, solar…)