That question is so last week. (I do like the Godzilla graphic, though.)
Or as James Taranto says, “Oh, Look! A Squirrel!”
I consider myself on the cutting edge of important news. Go ahead and ask me anything about Knut the polar bear’s demise.
From what I understand from talking to engineering students (and one non-practicing yet degreed fellow): There’s actually a very good chance that the core did indeed melt down, but was contained well enough by the primary containment structure.
From what I gather – and I have to emphasize that this is my opinion from what’s been said – they don’t want to do the extreme solution of burying the structure in concrete and simply abandoning the region for miles around because 1. The radiation levels aren’t *that* bad, nor is it clear yet whether they’re long lasting forms, and 2. They really hope to get things cooled down enough to where they can get machinery – or even engineers – into the area and separate and secure the fuel elements, if possible. That way, they don’t have to worry about a core buried in a huge mass of concrete possibly going critical again because it’s still altogether in one mass.
Again, that’s supposition from what I’m reading. I don’t know much about nuclear engineering, so I’m **DEFINITELY** subject to correction by those who know more than I. If anyone does, please sound off and correct anything I may have gotten wrong.
Oh, I forgot to separate the first and second paragraphs with the caveat that people who hope to secure and separate the fuel elements hope that the core did NOT melt down. If it did, then everything else is academic; it’d all be one amorphous pile of what’s called “corium”: http://en.wikipedia.org/wiki/Corium_(nuclear_reactor)
Let’s hope there’s not a meltdown. Separating the fuel elements from each other to prevent future criticality would be the best thing that could happen, from what I understand. Again: Anyone with more knowledge than I should sound off and correct anything I might have wrong.
Once more, the blogs demonstrate more informative capacity than newspapers.
There’s actually a very good chance that the core did indeed melt down, but was contained well enough by the primary containment structure.
WHAT? You mean the safety measures actually WORKED? Despite all the hysterical pronouncements?!!? NAAAwwww…
Just what do you all mean when you use “criticality”? Going critical used to mean, to me, an uncontrolled nuclear chain reaction resulting in a big kablooie within microseconds. Fuel rods cooking themselves because of coolant lack til they melt is something else again.
IMO the problems at the Daiichi reactors merely demonstrate the relative safety of nuclear energy. We don’t yet know what doses the workers have received to so far, but we do know that no one off site has been exposed to radiation levels that constitute a public health concern. And, that is likely to continue until total containment is achieved.
However, we can be confident that in the weeks and months ahead swarms of fish with 3 tails and a few kittens with 2 heads will be discovered and spawn a thousand cover up conspiracy theories.
I printed it out and put it up on the wall at work. It compares radiation dosages from a variety of sources. It’s pretty new because it mentions Fukushima in a couple of places.
One amusing fact is that Americans who left Japan and flew back to the U.S. got a higher radiation dose from the plane flight than they would have gotten if they had stayed put.
From the post: “Or maybe — even better — the MSM could learn to start reporting on nuclear incidents like journalists instead of activists from Greenpeace and Friends of the Earth”
Rubbish, the media acted like a bunch of people set on selling shedloads of newspapers. Like they always do. Capitalism at its worst.
Ah, but they were APPEALING to the Luddite Greenies, you see.
And you completely dodge the issue of what their honorable conduct should be — to report what’s going on as accurately as possible.
“Meltdown” is non-technical, ambiguous term. It can mean literal melting of the core, including cladding of fuel rods and fuel pellets themselves, melting of only zirconium cladding, partial or complete, or just losing of hermeticity of some rods due corrosion. It seems that only the last thing happened, so some volatile nuclides escaped from the vessel with the steam after venting the vessel. The difference is huge, because volatile components can not contaminate soil and ground water for long. They are either short-lived (iodine, half life 8 days), chemically inert (noble gases) and swiftly disperse, or both.
Rubbish, the media acted like a bunch of people set on selling shedloads of newspapers. Like they always do. Capitalism at its worst.
I don’t have a problem with that. I do have a problem with them being virtually the only ones talking.
I’d think this would be a great opportunity for level-headed newspapers and news networks to say: (a) no, there is no crisis, and stop pretending there is; (b) the safety mechanisms actually worked, in spite of being pushed past their design limits, and we can be proud of that and grateful for it; (c) here are the details and stats, to demonstrate that we’re not sellouts to some vested interest or other; and (d) our honorable opponents are trying to get rich by scaring you to death.
Is there money to be made with that message? I’d think there is. Who will step up and start making it?
respectfully,
Daniel in Brookline
@Tom:
If I’m understanding the folks I’m talking to correctly, ‘critical’ is actually a laymans term, so it’s used loosely. When I said it, I was using the dominant definition, which is merely a self-sustaining reaction (with “supercritical” referring to an accelerating reaction, but none of them actually referring to the mass going “BOOM!”).
An engineering student told me that nuke engineers are actually more specific: They use a measurement called “K”. K is the ratio between neutrons released in one “generation” of fission and neutrons released in the subsequent generation that’s touched off by that first fission event. When K is less than 1, the reaction is slowing down; the fissionable material is experiencing fewer and fewer instances of actual fission. This is when the fuel mass is “subcritical”. When K is more or less equal to 1, it is self sustaining, and laymen can call that “critical”. When it K > 1, that is “supercritical”. When K is way, way the heck above 1, it’s accelerating greatly, possibly out of control. I’m not certain what K value is considered an actual nuclear explosion, but I do believe there are factors above and beyond mere fission rate that determines whether something actually explodes or merely gets super, super hot. That’s actually a good question to pose to those students and one engineer I was referring to earlier. I’ll ask them.
Parker Says:
IMO the problems at the Daiichi reactors merely demonstrate the relative safety of nuclear energy.
Exactly! This was a pair of conjoined natural disaster scenarios exceeding the design parameters of a 60’s-era reactor, and the only deaths remotely attributable to the plant issues is 1 worker who accidentally got crushed by machinery, and several elderly patients in a hospital that got abandoned by their caregivers. Not a single one of those deaths were directly from the radiation leaks themselves.
Newer generations of plants are even safer.
I really wish news organizations would gain and provide some perspective on this (yeah, I know, laugh all you want at that, but I’m serious: I really wish they would). It is indeed a disaster, it does indeed have future ramifications, but on the other hand, it is not a Chernobyl or something that would prevent people from returning to the area in the near future. Unless there was a leak of the actual core fuel material and the subsequent long-lived fission reaction products (like cesium, strontium, etc.), then there’s nothing that can’t be cleaned up.
I hate to sound like some Greenpeace lunatic, but frankly, coal and oil fired power plants have killed more people in the course of normal operation than nuclear plants have during disasters. Those have done so through everything from mining disasters to creating air pollution and skewing the death rate for asthmatics and other people with respiratory problems. The only people to die directly from radiation during a nuke accident were the engineers and firefighters at Chernobyl, and that design was horrid compared to even Fukushima, let alone new generations of reactors.
It’s driving me nuts, but society keeps on overstating the risks of nuclear plants. I feel like tearing my hair out sometimes at it.
I think it’s likely that there was at least partial melting of the cores in reactors 1, 2, and 3. They were apparently partly uncovered by water for a while. I don’t know about the spent fuel pools in reactors 3 & 4, which I think is where most of the radiation came from.
There was also partial melting of the core at Three Mile Island. The containment structure is designed to, well, contain the fuel and the radiation even if the core melts completely. Chernobyl lacked a proper containment vessel, which as we saw was an extremely bad idea.
If you study that XKCD chart I posted earlier, you can see that Chernobyl was several orders of magnitude worse than either Fukushima Daiichi or Three Mile Island.
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That question is so last week. (I do like the Godzilla graphic, though.)
Or as James Taranto says, “Oh, Look! A Squirrel!”
I consider myself on the cutting edge of important news. Go ahead and ask me anything about Knut the polar bear’s demise.
From what I understand from talking to engineering students (and one non-practicing yet degreed fellow): There’s actually a very good chance that the core did indeed melt down, but was contained well enough by the primary containment structure.
From what I gather – and I have to emphasize that this is my opinion from what’s been said – they don’t want to do the extreme solution of burying the structure in concrete and simply abandoning the region for miles around because 1. The radiation levels aren’t *that* bad, nor is it clear yet whether they’re long lasting forms, and 2. They really hope to get things cooled down enough to where they can get machinery – or even engineers – into the area and separate and secure the fuel elements, if possible. That way, they don’t have to worry about a core buried in a huge mass of concrete possibly going critical again because it’s still altogether in one mass.
Again, that’s supposition from what I’m reading. I don’t know much about nuclear engineering, so I’m **DEFINITELY** subject to correction by those who know more than I. If anyone does, please sound off and correct anything I may have gotten wrong.
Oh, I forgot to separate the first and second paragraphs with the caveat that people who hope to secure and separate the fuel elements hope that the core did NOT melt down. If it did, then everything else is academic; it’d all be one amorphous pile of what’s called “corium”: http://en.wikipedia.org/wiki/Corium_(nuclear_reactor)
Let’s hope there’s not a meltdown. Separating the fuel elements from each other to prevent future criticality would be the best thing that could happen, from what I understand. Again: Anyone with more knowledge than I should sound off and correct anything I might have wrong.
Once more, the blogs demonstrate more informative capacity than newspapers.
Why do we need newspapers, again?
===========================
Radiation Doses For The Layman
===========================
http://people.reed.edu/~emcmanis/radiation.html
WHAT? You mean the safety measures actually WORKED? Despite all the hysterical pronouncements?!!? NAAAwwww…
Just what do you all mean when you use “criticality”? Going critical used to mean, to me, an uncontrolled nuclear chain reaction resulting in a big kablooie within microseconds. Fuel rods cooking themselves because of coolant lack til they melt is something else again.
IMO the problems at the Daiichi reactors merely demonstrate the relative safety of nuclear energy. We don’t yet know what doses the workers have received to so far, but we do know that no one off site has been exposed to radiation levels that constitute a public health concern. And, that is likely to continue until total containment is achieved.
However, we can be confident that in the weeks and months ahead swarms of fish with 3 tails and a few kittens with 2 heads will be discovered and spawn a thousand cover up conspiracy theories.
There is a fascinating radiation dose chart here:
http://xkcd.com/radiation/
I printed it out and put it up on the wall at work. It compares radiation dosages from a variety of sources. It’s pretty new because it mentions Fukushima in a couple of places.
One amusing fact is that Americans who left Japan and flew back to the U.S. got a higher radiation dose from the plane flight than they would have gotten if they had stayed put.
From the post: “Or maybe — even better — the MSM could learn to start reporting on nuclear incidents like journalists instead of activists from Greenpeace and Friends of the Earth”
Rubbish, the media acted like a bunch of people set on selling shedloads of newspapers. Like they always do. Capitalism at its worst.
Ah, but they were APPEALING to the Luddite Greenies, you see.
And you completely dodge the issue of what their honorable conduct should be — to report what’s going on as accurately as possible.
“Meltdown” is non-technical, ambiguous term. It can mean literal melting of the core, including cladding of fuel rods and fuel pellets themselves, melting of only zirconium cladding, partial or complete, or just losing of hermeticity of some rods due corrosion. It seems that only the last thing happened, so some volatile nuclides escaped from the vessel with the steam after venting the vessel. The difference is huge, because volatile components can not contaminate soil and ground water for long. They are either short-lived (iodine, half life 8 days), chemically inert (noble gases) and swiftly disperse, or both.
Rubbish, the media acted like a bunch of people set on selling shedloads of newspapers. Like they always do. Capitalism at its worst.
I don’t have a problem with that. I do have a problem with them being virtually the only ones talking.
I’d think this would be a great opportunity for level-headed newspapers and news networks to say: (a) no, there is no crisis, and stop pretending there is; (b) the safety mechanisms actually worked, in spite of being pushed past their design limits, and we can be proud of that and grateful for it; (c) here are the details and stats, to demonstrate that we’re not sellouts to some vested interest or other; and (d) our honorable opponents are trying to get rich by scaring you to death.
Is there money to be made with that message? I’d think there is. Who will step up and start making it?
respectfully,
Daniel in Brookline
@Tom:
If I’m understanding the folks I’m talking to correctly, ‘critical’ is actually a laymans term, so it’s used loosely. When I said it, I was using the dominant definition, which is merely a self-sustaining reaction (with “supercritical” referring to an accelerating reaction, but none of them actually referring to the mass going “BOOM!”).
An engineering student told me that nuke engineers are actually more specific: They use a measurement called “K”. K is the ratio between neutrons released in one “generation” of fission and neutrons released in the subsequent generation that’s touched off by that first fission event. When K is less than 1, the reaction is slowing down; the fissionable material is experiencing fewer and fewer instances of actual fission. This is when the fuel mass is “subcritical”. When K is more or less equal to 1, it is self sustaining, and laymen can call that “critical”. When it K > 1, that is “supercritical”. When K is way, way the heck above 1, it’s accelerating greatly, possibly out of control. I’m not certain what K value is considered an actual nuclear explosion, but I do believe there are factors above and beyond mere fission rate that determines whether something actually explodes or merely gets super, super hot. That’s actually a good question to pose to those students and one engineer I was referring to earlier. I’ll ask them.
Exactly! This was a pair of conjoined natural disaster scenarios exceeding the design parameters of a 60’s-era reactor, and the only deaths remotely attributable to the plant issues is 1 worker who accidentally got crushed by machinery, and several elderly patients in a hospital that got abandoned by their caregivers. Not a single one of those deaths were directly from the radiation leaks themselves.
Newer generations of plants are even safer.
I really wish news organizations would gain and provide some perspective on this (yeah, I know, laugh all you want at that, but I’m serious: I really wish they would). It is indeed a disaster, it does indeed have future ramifications, but on the other hand, it is not a Chernobyl or something that would prevent people from returning to the area in the near future. Unless there was a leak of the actual core fuel material and the subsequent long-lived fission reaction products (like cesium, strontium, etc.), then there’s nothing that can’t be cleaned up.
I hate to sound like some Greenpeace lunatic, but frankly, coal and oil fired power plants have killed more people in the course of normal operation than nuclear plants have during disasters. Those have done so through everything from mining disasters to creating air pollution and skewing the death rate for asthmatics and other people with respiratory problems. The only people to die directly from radiation during a nuke accident were the engineers and firefighters at Chernobyl, and that design was horrid compared to even Fukushima, let alone new generations of reactors.
It’s driving me nuts, but society keeps on overstating the risks of nuclear plants. I feel like tearing my hair out sometimes at it.
I think it’s likely that there was at least partial melting of the cores in reactors 1, 2, and 3. They were apparently partly uncovered by water for a while. I don’t know about the spent fuel pools in reactors 3 & 4, which I think is where most of the radiation came from.
There was also partial melting of the core at Three Mile Island. The containment structure is designed to, well, contain the fuel and the radiation even if the core melts completely. Chernobyl lacked a proper containment vessel, which as we saw was an extremely bad idea.
If you study that XKCD chart I posted earlier, you can see that Chernobyl was several orders of magnitude worse than either Fukushima Daiichi or Three Mile Island.