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New Threat To Seaside Nuclear Plants, Datacenters: Jellyfish
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."
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.
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.
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".