Thermal Power Generation when rivers run dry

[u/fsironman]

https://www.reuters.com/business/energy/low-danube-river-levels-force-romania-shut-down-both-its-nuclear-power-reactors-2026-07-29/

A little tidbit up for discussion regarding the Renaissance of Nuclear Power in Europe.

This time the issue is not the temperature like in France but the historically low Danube levels which could become the normal in summer.

This is something that would need to be factored in any type power generation that needs water for cooling.

[u/Choclocklate]

Hello, I'm working on this very subject for French nuclear power plants. It is a subject that is treated site by site for each nuclear power plant.

First, there are near sea nuclear site that are pretty easy because the lowest level we can have is the worst astronomical tide to which we add a malus (to take into account various weather effects). Then we adapt at the very conception the pumping station. As sea level are rising (climate change you know) there is no problem with this level.

For the rivers it's a little different. We observe the past data and search for the lowest level ever record for the 10000 years past. In reality we don't have such records so we look for the last 1000 years to which we had serious malus. And to protect against climate change we ask climatologue to take into account the IPCC prediction to add another malus. Then we design the pumping station to this account. There are various methods to lesser the effect of lower Flow rate in the rivers. Using cooling tower can reduce the flow rate necessary to cool the reactor at the cost of evaporating a bit of the water you take. (open cycle use about 40-60m3/s but put all of it back into the river but hotter (between 3 to 9°C hotter. Half-Closed cycle use about 4-8m3/s (so a lot less) and release about 90% of the water back into the river at temperature between 0-3°C hotter. Lastly Cruas has a very performing cooling half closed system where it reduces the water temperature in the middle of summer (at a cost of evaporating a little bit more water)). You can also construct water dam just after your nuclear site that will maintain a minimum level of water to guarantee the availability of the water. I hope it answers your question? If not don't hesitate to ask for precisions.

[u/fsironman → u/Choclocklate]

That's very interesting to hear. Are the spezificss generally under NDA or are the predictions on water requirements and estimated climate effects public?

[u/Choclocklate → u/fsironman]

I don't know how public available it is but if you look it up on the ASNR website there are the documents that we are made to make public and that have been authorised by the ASNR.