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  • Hacker News
  • "The Danube runs 2,857km (1,775 miles) through 19 countries."

    BBC can't even check Wikipedia.

    by Nux
  • So nuclear isn't the solution after all.
    by pjmlp
  • Nuclear without greed is fine.

    Its only where shortcuts have been taken with cooling that there will be issues.

    by bratbag
  • I ask once again: why is everyone so convinced that nuclear is the one technology that somehow doesn't get cheaper and better with advancing tech and scale? And don't tell me learning curves are proven to not apply. The preconditions for learning curves are arguably only now being met in China.
    by chermi
  • Go and invent an awesome nuclear plant then.
    by inigyou
  • > 4,700 cubic metres per second in July, whereas on Wednesday it was down to less than a third of that, at 1,600cm per second.

    Did a double take at measuring water flow in cm per second. At least it isn’t in busses or Eiffel or something.

    by lostlogin
  • Seems reasonable to me, same metrics used in Pooh Sticks.
    by blitzar
  • I find it interesting the discussion here is entirely about water temperature whereas the shutdown is entirely about NPSH.

    True there is a small different in NPSH pump limit of hot summer water vs cold winter water, but not as much as you'd think.

    Its not that the intake pipes are hanging out in the breeze above water; most pumps are designed not to cavitate at a certain input pressure (often pretty low) and I was bored enough to look it up and when the river is 134 cm below reference at this site, the pumps will be very unhappy long term if you keep sucking water in. They'll keep running, at a reduced rate, but cavitation will cause serious issues. At some sites, perhaps not this site, filtration systems (grates and stuff) on the input are designed for a certain ideal pressure and ideal flow rate, so that can also be a problem.

    Thermal limits are also very arbitrary and designed to a financial limit. Most plants worldwide are limited to a delta V, I suppose there could exist an environmental law that limits to an arbitrary fixed temp. Normally if 10 gallons/sec heats up 10 degrees, then 100 gallons/sec would only heat 1 degree. But it would cost 10x as much and only be needed a couple days/year in the driest summers, so a tradeoff point, well chosen or not, was selected. Most absolute limits are utterly ridiculous like 90F. The only long term way to maintain a river at or above 90F is an air dew point of 90F and most people will be dead by then. I find it improbable the water temp is too high, everyone without air conditioning would already be dead if the dew point were substantially over 90F. You could probably "cook" a small lake or dam area with a nuclear plant into something like a giant hot tub, but not a free flowing river.

    Looking at the mass media coverage, its mostly pictures and discussion of low water levels (the true cause) followed by journalist and consumer discussion about water temps, there is no meeting of the minds between the engineers and the general public and AI and journalists.

    If for whatever weird reason, river levels were low in the winter, low NPSH at the pumps would shut it down just as effectively at a water temperature of 1 C. Large industrial water pumps react extremely poorly to low input pressure.

    by VLM
  • NPSH = Net Positive Suction Head
    by Maledictus
  • Related: https://news.ycombinator.com/item?id=49107044
    by _tk_
  • You can totally retrofit existing nuclear power plants for closed loop cooling. I'm not sure what the cost would be, though, but it might be worth doing.
    by pepperoni_pizza
  • I believe there was also a planned much cheaper retrofit to use pumps to increase force to necessary levels but it was scrapped.
    by Pay08
  • Is it economically viable to run though? Natural draft towers or direct body of water cooling is used almost universally since it doesn't take any extra power. A large chunk of the powerplant's output would be running heat pump compressors to stop itself from exploding.
    by moffkalast
  • I've read that in the case of Paks a retrofit doesn't make sense because the entire thing is so old and needs to be rebuilt anyway.

    However, hopefully, they change the plans for (stalled project) Paks 2, because that would've used the same cooling system as the first one.

    by Elfener
  • Where have all the "what do you do when the wind doesn't blow and the sun doesn't shine" commenters gone?
    by blitzar
  • They are busy hitting downvote on comments on HN!
    by emsign
  • Don't solar panels have the same problem with heat?
    by LunaSea
  • Where are the comments about „molten-salt reactors dont need any of that”.

    And a closed water loop. China builds them on a desert and we cannot build them anywere in Europe due to plain stupidity.

    by pojzon
  • Of course a 1960's design isn't adapted to current weather conditions. That doesn't mean the whole technology is useless, like so many commenters imply.

    Any new build can and will include cooling adapted to hotter conditions.

    by Luc
  • And new builds take a lot of time and a lot of money.

    And then you habe the whole Russian drone war thing, where concentrating so much energy production on one point maybe be a bad idea

    by croes
  • The one that shut down in Romania is a CANDU, built in the 80s.
    by riffraff
  • It's not matter of "can", it's a matter of "how much does it cost?" and "who pays for that?".
    by exploderate
  • There's a nuclear reaction in the sky beaming free energy to us, let's just use that
    by one33seven
  • I wonder if any new hunger stones have been found since the Danube's wafer level reached this new record low.

    https://en.wikipedia.org/wiki/Hunger_stone

    by Triesault
  • They found mamooth bones!

    Edit: add source [ger] https://science.orf.at/stories/3236752/

    by yls
  • Here in Switzerland during some heatwaves they have to shut down nuclear plants too because the river water is too warm and adding warm water to it would kill the fish.
    by comrade1234
  • Would a cooling pond with controlled discharge into the river maybe mitigate this problem? One could also cycle the water from the cooling pond through the plant's cooling loop. The worse that could happen is evaporate the water from the cooling pond which is gets replaced with new water (sans fish) from the river.
    by petre
  • And it's not cold enough to cool the reactor
    by number6
  • This is happening all across Europe right now - Romania, France too.

    https://www.euronews.com/business/2026/07/13/france-shuts-do...

    https://www.reuters.com/business/energy/hungarys-paks-nuclea...

    We keep having folks here argue that nuclear, not renewables are the path to take to get rid of fossil fuels. I have strong doubts - it feels like that doesn't account for the sad realities of climate change.

    by vrganj
  • Different reasons though, France has nothing to do with water level or availability. It's for environment protection.
    by flr03