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Massive quake hits Japan 9.0 Magnitude

tepco stated that the chances of fuel in the basin reaching criticality again is not zero

NHK is showing smoke or vapor coming from the reactor nr 4 ... looks like the fire isn't quite out as claimed earlier
 
Apple OC said:
They just did not predict a tsunami of this scale causing the situation we are now faced with.

Unfortunately it takes something like this to correct mistakes moving forward. That being said ... this will get fixed.
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i understand the exceptionality of the situation, and that it might account for the triple redundant safety system failure.

still, the possibility of a failure in the reactor cooling system is taken into account, and in fact everything is encased into multiple containment systems

however the spent rods are apparently kept in an OPEN pool on the top floor of the reactor, with NOTHING except a regular roof separating it from the environment.

i just find incredible that the design would contain such a glaring oversight of the possibility that they might not be able to re-fill the pool with fresh water for some extended amount of time.

it seems something you should build into the design, no?
 
Don't panic said:
however the spent rods are apparently kept in an OPEN pool on the top floor of the reactor, with NOTHING except a regular roof separating it from the environment.
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How about putting the spent rods at ground level, and the emergency generators on the top floor of the reactor, away from flood waters??
 
How long is the expected fuel cycle for your average plant? I know here in the states, many plants get their permits extended well beyond the original stated lifespan of the plant.

Maybe this happened, and as a consequence, more fuel was consumed than anticipated?

Grasping at straws with this - because I agree, that is a downright lousy storage location - there must be something more to this. :confused:
 
Big-TDI-Guy said:
How long is the expected fuel cycle for your average plant? I know here in the states, many plants get their permits extended well beyond the original stated lifespan of the plant.

Maybe this happened, and as a consequence, more fuel was consumed than anticipated?

Grasping at straws with this - because I agree, that is a downright lousy storage location - there must be something more to this. :confused:
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Without digging around too much to find the specifics, you have to consider that this was designed in the 70's, and built in the 80's. It's not exactly a tour de force for safety regulations; the pool was simply meant as a stop gap to get the rods away from workers when they were doing maintenance below. As far as I can tell they weren't for storing any rod for a long period of time... if I have some more time I'll poke around for the specifics of this reactor though.
 
i think that the issue of the spent fuel 'temporary' storage might be really critical here.
i suppose it depends on where are the 'permanent' storage sites for japan's fuel, and what's their capacity.

if the issues are anything like in the US (for what i have read) the temporary storage longly outlasts the designed-for period because of problems with the permanent sites.
so all the available storage pools get used. plus, this would happen anyway, because the rods need to be spaced as much as possible to avoid them triggering each other and going critical.

if this is the case, than it is likely that all the pools (1-6) have significant amount of spent rods, which again begs the question of why containment is not considered a priority, especially given the very peculiar location of the pools, just above the reactors.
 
I think I can partially understand the location. "Above" the reactor, from the sketch I saw on Wikipedia, is not exactly accurate, they are on the upper level, but a little to the side. You put it there because you lift the rods out of the core, so you have them, all aglow, at the top of the vessel. Hence, you want the quenching water as close at hand as possible. Note that these pools are at least 40' (13m) deep, which is quite a lot of water, which also serves to absorb and mediate the neutrons. Under reasonably normal circumstances, circulating and replenishing the water is not a problem, especially when you have a nice big 40' margin for error.

From what I was reading, they replace a third to a half the core every twelve to eighteen months, and the spent fuel rods need to lounge in the pool for two to four years before they are safe to move. Hence, best case, the pool would contain at least two thirds worth of a core. Assuming, of course, that Nuclear of Nippon has a plan and a repository for dealing with the waste.

Reactor 1 started commercial operation in '71 and was granted a ten year extension this year, instead of being decommissioned. #6 has been producing for 32 years. For a nuclear power plant, that sure seems to me a long time to be in operation for the amount of intense radiation the hardware is exposed to.
 
They prolly should be adapting plants in the "good areas" to be building parts for sarcophoguses at this point so they can rapidly wall up the reactors. Either that, or start importing all the parts from China or something and start making sections and stuff. It doesn't look like they can contain it and I wouldn't be surprised if more reactors explode.

:::::

On SCI if interested:

Next Wave, The: Science of Tsunamis

http://science.discovery.com/tv-schedules/special.html?paid=48.16349.25052.0.0
 
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Don't panic said:
a good article from der speigel

http://www.spiegel.de/international/world/0,1518,750773,00.html
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This article is terrible. So much FUD.

Experts at the site reported that radiation levels of one sievert per hour had been measured near the reactor. This is a high level, but nothing compared with the 200 sievert per hour to which some emergency workers in Chernobyl were exposed.
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"One sievert per hour near the reactor"? This is less than the cosmic radiation you are exposed to while flying in an airplane. It's dangerous if you are a worker inside the reactor. If you live a mile away? It's negligible. Twelve miles away? It's not even a detectable difference.

Arrogant Attitude

The fact that Japan, which was once considered a miracle economy, was on the verge of a nuclear disaster could be far more devastating to the nuclear industry than the Soviet reactor catastrophe in Chernobyl could ever have been a quarter century ago.

Admittedly, Japan is in an earthquake zone, which puts it at greater risk than countries like Germany and France. But Japan also happens to be a leading industrialized nation, a country where well-trained, pedantically precise engineers build the world's most advanced and reliable cars.
When the Chernobyl accident occurred, Germany's nuclear industry managed to convince itself, and German citizens, that aging reactors and incapable, sloppy engineers in Eastern Europe were to blame. Western reactors, or so the industry claimed, were more modern, better maintained and simply safer.

It is now clear how arrogant this self-assured attitude is. If an accident of this magnitude could happen in Japan, it can happen just as easily in Germany. All that's needed is the right chain of fatal circumstances. Fukushima is everywhere.
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Do they realize that this 40-year-old nuclear site survived a 9.0 Earthquake, and was only finally knocked offline by the tsunami? This level of disaster cannot happen in Germany, and couldn't happen in Japan either if they'd built on an elevation like all of the other nuclear sites there.

So far there has not been an explosion emitting radioactive material. The explosions that have occurred have been of hydrogen. This isn't Chernobyl and there hasn't been an environmental impact yet, and the radiation levels are low enough that there's no noticeable change in radiation levels a few miles away. Unless it worsens, so far this has been a testament to the durability of these reactors. The entire plant was knocked offline with a 9.0 earthquake and then literally drowned underwater by a tsunami that broke the backup power generators and has still not leaked any wastes.



In fact, I'd go so far as to say this is the worst article I've read on it.

Why is this the 9/11 of the nuclear industry?

There has yet to be one death nor any environmental contamination. This is a scare article and nothing but, until we actually have radioactive waste leakage.
 
Below is what started as a blog post, and is now a chain email. Below it is discussion on authenticity.

http://worldpartytokyo.blogspot.com/2011/03/311-japan-earth-quake-news17-fukushima.html (< this is not the original source)



There's been some criticism of it; it seems the Dr. Josef Oehman's PhD is not in nuclear physics, and that he is a mechanical engineer according to MIT.

And to show all spectrums, here is an article claiming to "debunk" it:
http://www.salon.com/news/politics/war_room/2011/03/15/josef_oehmen_nuclear_not_worried_viral/

That said, none of the "debunkings" actually demonstrate that what the article says about the operations of nuclear sites is incorrect, and merely attack his credentials. So, read in to this what you'd like, and perhaps the predictions with a grain of salt, but it provides a much better technical view of what is happening over there.
 
GFLPraxis said:
"One sievert per hour near the reactor"? This is less than the cosmic radiation you are exposed to while flying in an airplane.
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I think you have your units confused.... (1 mSv = 0,001 Sv)

1666cb7da4d45e9f7d55595b33043643.png

[Source]
 
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tkermit said:
I think you have your units confused.... (1 mSv = 0,001 Sv)

1666cb7da4d45e9f7d55595b33043643.png

[Source]
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You are correct, sir.

However, I'd really like to see a source on this, because it completely contradicts everything I've read on the disaster. In fact, all the sources I've seen indicates that the big radiation spike this morning was measured in microsieverts. Example source: http://www.nytimes.com/cwire/2011/0...levels-spike-forcing-temporary-ret-87245.html

The 50 remaining emergency workers were withdrawn Wednesday morning local time after smoke or steam emerged from Unit 3, press reports said. Japanese authorities said that morning radiation readings had ranged between 600-800 microsieverts per hour, but at 10 a.m., readings rose to 1,000 microsieverts per hour. Readings began to fall again an hour later.
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There's a 1000x discrepency between the NY times article and this article's claims. And both are referring to inside the facility.
 
Don't panic said:
not really: the nyt article says the spike was >1000mS/hours which is 1 Sievert/hour.
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No, the NYT article says 1000 micro sieverts, not mSv (which would be millisieverts).

1000 microsieverts is a millisievert.

A sievert is 1,000,000 microsieverts.
 
GFLPraxis said:
No, the NYT article says 1000 micro sieverts, not mSv (which would be millisieverts).

1000 microsieverts is a millisievert.

A sievert is 1,000,000 microsieverts.
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yep, you're right. i had misread it as milli but the correction wasn't quick enough apparently :)

in any case, the 'don't worry let's have a picnic at Fukushima at noon tomorrow' guy seems correct in many aspects, but very inaccurate in most technical issues.

there is a "corrected" version of it at an MIT site (linked by the Salon debunking article).

here the many inaccuracies (e.g. melting temperatures, operating pressures, damages caused by seawater and most other technical details), are amended, together with the editorializing but the main ideas and the structure of the article are kept.
they do not come to the same absolute conclusions, though.


in my view it overlooks a couple of important aspects.

the first one is the holding pools.
those are possibly going to be the main source of contamination, and if they melt (and the fires indicate that they might be getting there), they will release cesium and other problematic materials, and not necessarily in traces. and if there was nothing to worry about , why they can't even get close enoughto the pool for the short time necessary to set up a pump to refill them?

the second is that dr ohemen. makes the same error (on the other end of the spectrum) of the chicken-littles: he reasons in absolutes. the fact that the outer containment shell is designed to contain a full meltdown, doesn't mean that it necessarily will under these specific circumstances, especially after sustaining an earthquake much stronger that what it was designed to sustain.
 
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Don't panic said:
yep, you're right. i had misread it as milli but the correction wasn't quick enough apparently :)
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Hehe, my bad, you ninja'd me with the edit while I was making my post.

But yeah, from everything I've seen excepting this article, the largest spike was around 1 millisieverts/hour within the complex (about five times what you get from an airplane flight, which is 200 microsieverts or 0.2 millisieverts), which, a mile away, should be negligible.

This article's suddenly claiming 1 Sievert seems out of the left field to me; I haven't heard of anything like that.

So far, radiation is leaking but not radioactive materials...I feel that calling this "Japan's Chernobyl" is exaggerated.

In fact, everything in the article is really 'touched up' for a good story.
In their desperation, the authorities authorized a controlled release of radioactively contaminated steam into the environment. Radioactivity levels within the plant rose to 1,000 times normal values, and radioactivity also became elevated on the entire site.

Reports that the pressure in the reactor container in Unit 1 had risen to six times atmospheric pressure seemed to herald impending disaster, because the reactor's protective shell can only withstand a pressure level amounting to eight times atmospheric pressure.

The situation at Fukushima escalated dramatically late Friday night. German nuclear expert Sailer likened the situation "to a disaster movie," as engineers desperately fought to gain control over the reactors. In the end, it was apparently a hopeless struggle.

The fuel elements had melted, at least partially, and apparently only the steel container housing the reactor and the containment layer were left, preventing the most highly radioactive materials from escaping. On Saturday evening local time, the plant's operators announced that they intended to flood the reactor with seawater, a last-ditch attempt to prevent the reactor vessel from melting. "They're basically trying to sink the reactor," says nuclear expert Mycle Schneider, who compiles the annual "World Nuclear Industry Status Report."
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The bolded line is utterly silly. The next paragraph explains that none of the radioactive materials had escaped and they still have contingencies they are planning to cool the reactor.

Röttgen reacted with irritation to the new nuclear debate that was already taking shape in Germany over the weekend. "I feel that this is uncalled for in this situation, and that it's really the wrong time," he said. Röttgen himself was unwilling to comment on the consequences for the planned extension of the life spans of nuclear power plants in Germany, calling it "a political discussion for another time."
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The way this is phrased is entirely intended to discredit him and make him look biased. Perhaps there's a reason he thinks that it is uncalled for?


And this is just an example of the manipulative writing in the article, leaving out the actual "Sievert" inaccuracy.
 
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tkermit said:
This graph seems to have been compiled from fairly reliable data/sources:
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interesting, thanks.
so it seems that outside the situation is ok, but spikes in the order of 1 Sieverts are probably likely within the reactor buildings.
there must be something or they'd just send someone to replenish the holding pools.

edit-post-edit: thanks sushi :)
 
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