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Author Topic: Japanese earthquake  (Read 20375 times)

Re: Japanese earthquake
Reply #15 on: March 11, 2011, 21:58:19 PM
2149: The Kyodo news agency is now citing a safety panel as saying that the radiation level inside one of the reactors at the Fukushima-Daiichi nuclear plant is 1,000 times higher than normal.
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Re: Japanese earthquake
Reply #16 on: March 11, 2011, 22:52:19 PM
Stupid boiling water reactors! looks like they're going to have to vent the steam from the reactor. I wonder what happened to the emergency cooling circulators. Most reactors have at least 4 circs and in shutdown condition one of them working would probably be enough. Certainly British reactors always have at least 3 backups for everything, would have thought the Japs would be similar.
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Re: Japanese earthquake
Reply #17 on: March 11, 2011, 23:15:08 PM
Looks like two stations are having issues:


2310: More from the Tokyo Electric Power Company: It says the ability to control pressure in some of the reactors at Fukushima-Daini has been lost. Pressure is stable inside the reactors, but rising in the containment vessels, a company spokesman says.

2252: The Tokyo Electric Power Company has said the cooling systems of three reactors at second nuclear power plant, Fukushima-Daini, are malfunctioning, according to the Kyodo news agency. The plant is 11km (7 miles) to the south of Fukushima-Daiichi, where the cooling system one of its reactors is not working and pressure is rising.   

2239: Japanese nuclear safety officials have said the problems at the Fukushima-Daiichi nuclear power plant represent "no immediate health hazard" to people living nearby. Some 45,000 people living within a 10km (6-mile) radius of the plant were told to evacuate as radiation levels rose to 1,000 times above normal in one reactor.   
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  • Offline Quixoticish

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  • Offline Shaun

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Re: Japanese earthquake
Reply #19 on: March 12, 2011, 01:27:19 AM
sh*t!

Brings our problems with the environment back in December into prospective :worried: 
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Re: Japanese earthquake
Reply #20 on: March 12, 2011, 14:10:21 PM
and now there's been a mag 6.0 aftershock on top of said nuclear power station.

The reactor whose building has blown up is an old design, circa 1970 according to Wikipedia. It seems like they may have deliberately vented coolant into the secondary containment to reduce pressure inside the reactor. Of course I don't know but it seems possible the secondary containment couldn't take the pressure. The other major possibility seems to be a hydrogen explosion, but the generation of hydrogen requires melted fuel so I'm hoping that's not what it is.
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Re: Japanese earthquake
Reply #21 on: March 12, 2011, 14:25:44 PM
I thought the idea was you could just drop the control rods and stop the reaction to stop stuff like this getting too serious?
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Re: Japanese earthquake
Reply #22 on: March 12, 2011, 14:38:59 PM
the emergency shutdown system will kill the chain reaction in around 10 seconds, but in a reactor which has been operating for any length of time there will be a large amount of radioactive waste products in the fuel. A lot of these decay quickly, releasing heat as they do so, so you have to keep the cooling system running for at least a few days after shutdown, otherwise your fuel rods heat up until the cladding melts and then you start to get real problems.

It's looking increasingly like they evacuated the site, then vented steam into the containment building. If there has been any melting of the fuel, the steam could well include hydrogen which then exploded, destroying the containment building. Since the reactor is a 1970s unit, they would have been thinking about decommissioning it shortly anyway, so they wont bother trying to repair it. They will therefore now cool it with sea water (probably the secondary coolant anyway) and everything should be fine.
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  • Offline Quixoticish

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Re: Japanese earthquake
Reply #23 on: March 12, 2011, 16:00:41 PM
It almost feels as though there is a bit of a media blackout in force with information coming out in dribs and drabs and the information only being released well after we already know it's happened.

Case in point being the reactor building. Everyone had seen the footage of the explosion tearing the roof and walls off yet everything official was debating about exactly which building it was that exploded.

When they finally admitted something it was that the "ceiling collapsed".

I think it's pretty safe to say based on past nuclear related accidents that people will be told much later than they should have been that anything untoward has occurred.
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  • Offline Serious

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Re: Japanese earthquake
Reply #24 on: March 12, 2011, 16:02:26 PM
Shut down? Think it is more blow up...

Huge blast at Japan nuclear power plant.

http://www.bbc.co.uk/news/world-asia-pacific-12720219
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Re: Japanese earthquake
Reply #25 on: March 12, 2011, 16:05:15 PM
that explosion was one hell of a bang, I'm just hoping it really was the hydrogen explosion scenario outlined above or something similar, rather than my initial reaction which was "my god, they've ruptured the pressure vessel".

Assuming what they're saying about the PV being intact is correct, then hats off to the Jap engineers, that's one impressive piece of engineering.
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Re: Japanese earthquake
Reply #26 on: March 13, 2011, 17:40:39 PM
from msn page looks like they are still having issues controlling the power plant situation
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  • Offline Mardoni

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Re: Japanese earthquake
Reply #27 on: March 13, 2011, 18:51:58 PM
Listening to BBC News, Reactor 3 is starting to have trouble and that's the one that could really spill some nasty crap out if it goes :s
They've accepted that they've lost the reactors and are pumping sea water in to try and cool them  :worried:
Last Edit: March 13, 2011, 18:58:12 PM by Nimrod #187;
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Re: Japanese earthquake
Reply #28 on: March 13, 2011, 18:54:13 PM
Some of the "Experts" on the BBC are saying that this is a desperate measure, and we could be about to watch the next Chernobyl.
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Re: Japanese earthquake
Reply #29 on: March 14, 2011, 00:37:48 AM
Things seems to be getting worse with every report rather than stabilising or getting better  :o :( :panic:
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