Hacker News Reader

Comment by AdamJacobMuller | Hacker News Reader

> French energy company EDF stated that it would shut down two nuclear reactors in an attempt to limit the amount of heating water used to keep the reactors cool at Golftech nuclear power plant.

I don't see why that would be a necessary or even good thing? Surely they must have higher demand for power from AC loads with the heat, even if AC isn't quite as prevalent in the EU as the US.

View on HN

This was done to prevent badly affecting the ecosystem of the rivers. The water from the river is used to cool down the plant, but the resulting warm water is poured back into the river. The temperature of the water going back to the river is carefully monitored and during heat waves it may be decided to shut down the plant. By the way this is not specific to nuclear at all, coal plants work the same, but France is the major exception in the world with 74% electricity coming from nuclear, and most of the rest coming from dams (extremely low carbon footprint for electricity). Some plant designs only use closed-circuit cooling which doesn't have this problem. The towers people usually associate with nuclear plants, is in fact a cooling tower that uses the air to cool the water. Again despite popular belief, these cooling towers are not just for nuclear, they are also used for coal plants (any thermal power plant)

The nuclear reactor of Grohnde in Lower Saxony, Germany is also currently being shut down. Like many reactors this one depends on a river (River Weser) for cooling. The water temperature of the Weser will reach 26° Celsius by tomorrow, which is a threshold value for serious damage to the ecosystem along the riverside – so the decision was made to not let the reactor contribute to further heatup of the river. The shut down is expected to last until sunday or monday.

It's necessary because the water used to cool reactors is rejected in rivers. In normal circumstances the temperature increase this causes is under control, but right now it risks endangering the wildlife in said rivers.

Because reactors need a lot of water as coolant, and they were designed with assumptions about how high the temperature of the water would be, which are now being broken. They started building that reactor in 1982, before they understood that temperatures were in the process of rising 1.5C (up to now).

The more accurate answer is that to not cook everything downstream they are forbidden from releasing to hot a water. If the upstream is already hot, they have no margin to not cook the fish downstream so they close shop. (It’s a bit more complicated since it depends also on the River size, but the main factor is downstream temp.)

Thanks for the correction.

Also to add, the water doesn't have to be hot enough to literally cook fish to be an issue - a big concern is how the different micro-organisms/plants/fish/etc react to the temperature change of there normal habitat.

France is EU's top energy exporter [0]

[0] https://www.reuters.com/article/france-electricity/french-20...

It is not a good thing. Just another piece of infrastructure affected by the heat. And a problem to solve - the higher the average temperature, the more limitations on cooling power plants with river water.

They just don’t have the cooling capacity on the hottest days.

I don't know about France, but domestic AC is almost unknown in the UK.

I wonder if "heating water" implies that coolant is being plumbed through buildings to heat them, which could be dangerous to the occupants of those buildings if they were already too hot. Or maybe France is suffering a drought at the moment.

Reply on news.ycombinator.com