New Threat To Seaside Nuclear Plants, Datacenters: Jellyfish 123
Nerval's Lobster writes "One of the largest nuclear-power plants in the world was forced to shut down temporarily Sept. 29, after pipes that bring Baltic Sea water in to cool the plant's turbines became clogged with tons of jellyfish. The sudden influx of common moon jellyfish overwhelmed the screens and filters that keep flotsam and most sea life out of the Oskarshamn nuclear plant in southeastern Sweden. The plant was forced to shut down its No. 3 reactor – the largest boiling-water reactor in the world, which generates 1,400 megawatts of electricity when it is jellyfish-free and running at full power. The reactor stayed down until early Oct. 1, after the jellyfish had been cleared out and engineers approved the cooling system as invertebrate-free. It's not easy to overwhelm the cooling system for a nuclear power plant, but Oskarshamn's is unusually resilient. There is a separate intake- and cooling system for each reactor, all of which were designed for the brackish, polluted water in that area of the Baltic Sea. Most datacenters are too far inland to worry about jellyfish in their cooling water, though green-IT-promoters Vertatique estimated that a 5,000-sq.-ft. datacenter would consume almost 9 million gallons of water for cooling. That means ocean-side datacenters that use sea water for cooling (such as Google's datacenter in Hamina, Finland — also on the Baltic Sea) are just as susceptible to jellyfish attacks as nuclear power plants."
And the worst part... (Score:5, Informative)
I guess we'll need a Geiger counter to figure out if they have a natural bioluminescent jellyfish glow, or if they are irradiated.
What language is this? (Score:5, Informative)
Jellyfish attack?
attack [uh-tak] ...
verb (used with object)
1.
to set upon in a forceful, violent, hostile, or aggressive way, with or without a weapon; begin fighting with: He attacked him with his bare hands.
2.
to begin hostilities against; start an offensive against: to attack the enemy.
Kind of implies a certain amount of forethought and/or planning. If jellyfish attacked the cooling system then I have a newfound respect for the intelligence of jellyfish.
Perhaps they simply infested the cooling system? Editors, they aren't just for breakfast any more.
Re:Do they have 3 eyes? (Score:4, Informative)
they're one eye.
not so sure about hamina being in same risk zone though(I think southern sweden has more of them than finnish side.. really I only remember seeing large amounts of them only when visiting sweden). also can't see why some added netting further away wouldn't take care of them. or maybe we should ask the russians to dump some more waste into the sea.
Not new (Score:5, Informative)
This is not a "new threat"; this is extremely common. A quick google comes up with at least 5 similar incidents in 2011 and 2012.
http://www.ibtimes.com/jellyfish-invade-four-nuclear-reactors-japan-israel-scotland-photos-707777 [ibtimes.com]
http://usnews.nbcnews.com/_news/2012/04/27/11432974-diablo-canyon-nuclear-plant-in-california-knocked-offline-by-jellyfish-like-creature-called-salp?lite [nbcnews.com]
Re:Why pump in sea water? (Score:5, Informative)
Mineralization is a big problem with that. It's easier to deal with mineralization (as well as having better heat exchange) by having a high flow rate at higher pressures, and that's done by pumping water in through piping. In industrial plants it's also not about volume, but more about mass flow rates, the mass is what moves heat around and a simple radiator typically doesn't cut it.
Of course they could do like most shipboard steam plants do and have some design in the plant that allows for a valve line-up that lets you purge the intake. More or less, it's a method of temporarily reversing the flow. (It's nowhere near efficient, but if you're blowing steam or pumping high pressure water out the intake, most typical flotsam and jetsam goes bye-bye. Anything that doesn't get requires a tear-down and/or divers.) Some steam powered ships also have more than one intake so they can be alternated for servicing, which is a nice redundancy feature.
It's been some years since I dealt with a little bit of that stuff, so I may be a bit fuzzy on it, but if you asked a plant operator I'm probably not too far off the mark.
Your "RDA of Useless Knowledge" post for the day: (Score:5, Informative)
It amuses me that the collective noun (you know, like a "pack" of dogs or a "flock" of birds or a "tantrum" of Representatives) for jellyfish is a "smack".
It's like you can just hear them smashing themselves into water intakes. "SMACK!".
We now return this thread to people with more directly relevant things to write.
Re:Why pump in sea water? (Score:5, Informative)
Heat transfer is proportional to the temperature difference between the return water and the surrounding (approach temperature), the surface area, and the thermal conductivity of the medium. Higher temperature differences reduce the thermodynamic efficiency, and fouling of the heat exchanger is going to reduce the thermal conductivity, as will the thicker metal that will withstand the corrosion. You also need to deal that without inducing water flow across the heat exchanger you are going to get stratification of warmer water and further reduce heat transfer.
But, the problem has been solved for a long time. In Hong Kong they use harbor water to run through the chillers for cooling buildings. You can't possibly get worse water than that no matter how hard you try. It takes a lot of maintenance and multiple stages of filters, but it works pretty well.
Jetsam, not flotsam (Score:5, Informative)
Since we are being pedantic about language, it is jetsam , not flotsam , that is clogging the pipe. Flotsam is floating debris. If the debris is drifting below the surface, it is jetsam. Since nuke intake pipes are always well below the surface, they cannot be clogged by flotsam.
Re:Jetsam, not flotsam (Score:5, Informative)
Since you want to be pedantic, neither term really applies. Flotsam is cargo or gear that floats away from a ship, eg accidentally lost. Jetsam is cargo or gear that is deliberately thrown overboard. The distinction makes a difference to the salvage rights if you find it. Since the jellyfish were never on a ship in the first place, they would come into a different category, eg "marine wildlife".
Re:Rampant Jellyfish (Score:4, Informative)
If an "effort" is required to get Japanese people to eat something that comes out of the ocean, you really don't want to go near it.
Kurage (jellyfish) have featured in the Japanese diet throughout history. There is no "effort" of which I'm aware, and I've been in Japan since 1991.
Re:Why pump in sea water? (Score:4, Informative)
not armchair /.ers....
As a mechanical engineer, I can say that armchair engineering can sometimes be a lot more fun than actual, real life engineering! :)
Re:Rampant Jellyfish (Score:5, Informative)
It's estimated that now over 50% of the biomass of the world's oceans is jellyfish, in some cases completely displacing all other biosystems. One other human activity vector that has impacted jellyfish populations is shipping, transporting species globally to locations with no predators. The warming of waters by nuclear power may locally cause phenomenon which encourage jellyfish growth also. If you could avoid destroying other marine life, maybe the answer to the cooling intakes is "will it blend?".
Japan’s nuclear power plants have been under attack by jellyfish since the 1960s, with up to 150 tons per day having to be removed from the cooling system of just one power plant.
...
That’s just what happened when the Mnemiopsis jellyfish (a kind of comb jelly) invaded the Black Sea. The creatures arrived from the east coast of the US in seawater ballast (seawater a ship takes into its hold once it has discharged its cargo to retain its stability), and by the 1980s they were taking over. Prior to their arrival, Bulgaria, Romania, and Georgia had robust fisheries, with anchovies and sturgeon being important resources. As the jellyfish increased, the anchovies and other valuable fish vanished, and along with them went the sturgeon, the long-beloved source of blini toppings.
By 2002 the total weight of Mnemiopsis in the Black Sea had grown so prodigiously that it was estimated to be ten times greater than the weight of all fish caught throughout the entire world in a year. The Black Sea had become effectively jellified. Nobody knows precisely how or why the jellyfish replaced the valuable fish species, but four hypotheses have been put forward.
from http://www.nybooks.com/articles/archives/2013/sep/26/jellyfish-theyre-taking-over/?pagination=false [nybooks.com]