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In reply to the discussion: Fukushima is an ongoing problem [View all]FBaggins
(26,748 posts)I can't tell you how many times that question comes up when I read your posts.
They can't even get in to where the cores have melted. They have sent robots in and the robots melt.
You do seem to have an incredibly unique reading comprehension problem. It doesn't seem to matter what words you're presented with... you somehow come away thinking that they support your nonsensical positions. You've repeated this type of robot claim dozens of times and it has never been correct. And now the robots are melting? Hilarious.
"Cores are not hot" "fuel rods take five years to cool down", you say. Contradictions from you, again.
Nope. That's you making up reality again - since I never said anything of the sort. I said that after five years they produce so little heat that you can place them in dry cask storage and don't need water at all. It's actually earlier than that... but that's the regulatory time-frame. It doesn't mean that they're hot right up until that point.
Heh. Three reactors were running when the place blew up. So, in the first few hours when they had no water, the fission went out of control. And blew.
Other than generally correct spelling, that entire sentence had no connection to reality. The reactors were not running when they blew up... they hadn't been running for over a day before the first explosion. The reactors shut down automatically when the earthquake hit. The tsunami didn't knock out power for about an hour after that. Decay heat created all of the damage that we watched... there was no active fission.
Units 2&3 (the larger models) each produced almost 2,400 MWs of heat when they were running at full power. That figure dropped to about 150 MWs the instant that the reactor SCRAMed and 120MWs within the first ten seconds. They're down to less than 50MWs after about 10 minutes.
About an hour after the shutdown (when the tsunami arrived), decay heat was down to about 1.5% of the full-power rating. The problem is that 30-40 MWs is still a lot of heat if the pumps aren't working. By the time the unit 1 blew, the decay heat in 2&3 was only 10-15 MWs, but they couldn't shed even that much without pumps and the meltdowns were well under way there as well.
But the difference between that heat and the amount they would put out if they were "fissioning out of control" is massive.
And, of course, now... over three years later... the shorter-lived isotopes are all gone and the decay heat is far easier to deal with. The equivelent of 3-4 garden hoses (each) is more than enough. Which is why the temperature in the reactors is so low.