Earthquake/Tsunami in Japan

Grall said:
If those rods are actually exposed to nothing but air, and dissipate on the order of 100MW or more of heat, then surely they would light up like lightbulb filaments and melt within minutes, if not seconds. There must have been some form of cooling of those rods, like water spraying/evaporating off of them, even if they weren't actually submerged...
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They're down to around 8MW or under, after shutdown it immediately drops to 10% (=76.8MW for Dai-ichi reactor 2 & 3), 24h from there under "normal emergency cooling" circumstances to 2% (=~15MW for Fukushima 2 & 3), 0.5-1% down every 24h from there.
Dai-ichi 1 is even lower as it's full capacity is lower too, can't remember how much though.
 
Kaotik said:
Dai-ichi 1 is even lower as it's full capacity is lower too, can't remember how much though.
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I can't remember the exact figure but it was around 450-500MW.


Reports have been saying all three reactors are in process of meltdown and radiation levels outside are twice as high as they have ever been in past few days and still climbing.
[edit]

Status to level 6 is expected to be announced in minutes
 
Last edited by a moderator:
Latest news is that reactor 2 has its core exposed again (BBC is reporting that this may be due to an "accidental" shutdown of an air flow gauge, which prevented more water being pumped in to the system).

Wikipedia also states that there has been a press conference with NHK news and TEPCO (Tokyo Electric Power Company), during which they confirmed that there has been a buildup of pressure which would need to be vented to allow more water to be pumped in, which currently isn't possible due to damage to the valve. I can't find any sources to support this news atm.
 
hoho said:
Reports have been saying all three reactors are in process of meltdown
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Well that can't be good. :(

...And by the way, why the hell are they holding a damn press conference before doing the venting where they talk about it first, isn't time kind of of the essence here? Jesus christ, just go ahead and DO IT.
 
Grall said:
Well that can't be good. :(

...And by the way, why the hell are they holding a damn press conference before doing the venting where they talk about it first, isn't time kind of of the essence here? Jesus christ, just go ahead and DO IT.
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I would be very surprised if the people actually involved in carrying out whatever steps necessary to stabilise the reactors are the ones talking to the press.
 
Also, venting means dumping a lot of radioactivity into the atmosphere.

It is a last resort kind of thing.

cheers
 
Grall said:
Well that can't be good. :(

...And by the way, why the hell are they holding a damn press conference before doing the venting where they talk about it first, isn't time kind of of the essence here? Jesus christ, just go ahead and DO IT.
Click to expand...
They're doing things as fast as they can, people having press conferences aren't the same guys as those actually doing the things.

As for the partial meltdown, it's not good, but not really that bad either, the 3 plants were practicly history before any meltdowns happened anyway due other damages, and as long as the melted core stays within the containemnt building, it's not really that much more dangerous than "unmelted core". Heck, I haven't even heard reports from the actual core vessels getting damaged yet. (There's the outer shell which has blown up on 2 plants, but that's pretty much just weather cover for the employees, then there's the actual containment building, in which is the core container in which is the core possibly melting down.)
 
Venting doesn't always mean putting a lot of radioactivity in to the atmosphere. They have already vented several times, and if the core hasn't started melting it only releases a few radioactive components with vanishingly short half-lives, which don't really pose a risk to anyone not standing next to the reactor. The problem with venting is when stuff starts melting, meaning you get progressively more dangerous materials released.

It seems that the melting situation is slightly worse than they originally feared during the more recent releases as ceasium and iodine have been picked up (half-lives of months and days, respectively).
 
Indeed, and almost all of the radioactive material that gets out with the steam has half-life of mere seconds, the amounts of idoine and cesium for example are really, really small fractions
 
Wild guess would be it's the image with tons of US citizen writing to facebook about how this is gods / natures payback for pearl harbor, how japanese deserve it etc etc
 
I presume the below tweet from BBC's Live coverage is part of the reason why Japan has sought IAIE assistance ...

2207: Japan's Chief Cabinet Secretary, Yukio Edano, has said a partial defect has been found inside the containment vessel of reactor 3 at the Fukushima Daaich nuclear power plant, the Kyodo news agency reports. He has also said the reactor is "not necessarily in a stable condition". Early on Tuesday morning, officials said pressure inside the container had dropped and sea water was being pumped in to cool the fuel rods.
 
Explosions heard at reactor building 2, the building is intact but apparently the core vessel might be broken
 
Apparently there's a crack in reactor 2's "wetwell" (the torus shaped part)
tumblr_lhzb23MSpu1qbnrqd.jpg


It's where the radioactive water goes from the core.
 
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