Fukushima Japan earthquake - contamination & consequences outside Fukushima NPP

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I think you may both be right; there is a desire to know more, but as I found with Fukushima, the more I learned, the more I discovered the limits to my understanding of nuclear physics, and the more I could see how easily people's perceptions could be swayed by shonky science and politically-biased studies. It is a daunting science if you are trying to study it as an amateur, and the task is made more difficult by the distractions of Michio Kaku and Arnie Gundersen, and the conspiracy theories that seemed to pop up like mushrooms. Even in the brief exchange above you can see the gulf that exists and is exploited by both sides. Is 100 bq in a tuna sandwich an existential threat? One side says 100 bq is less radiation exposure than you would get in a dental x-ray, and the other side says "yes, but you don't eat the x-ray machine", and no one becomes the wiser, they merely retreat into their entrenched camps of pro or anti nuclear.

For the anti-nuclear movement, nuclear science is in itself an original sin that taints every study, every observation, every epidemiological investigation, and therefore cannot be trusted, or worse, is part of a conspiracy. Conspiracy theories are attractive because they require less effort, and validate some human desire to believe that superior powers are working to manipulate you, and so merely believing in a conspiracy theory becomes an act of defiance, and is appealing to those who can't be bothered learning the difference between alpha, gamma, or beta radiation, or the esoterica of decay heat produced by a nuclear fuel bundle. And yes, both government and industry have kicked so many own goals that they are deserving of the suspicion with which the general public treats them.

By its nature, nuclear science defies easy understanding. The science is "dumbed down" for the benefit of people with an ever-shrinking attention span. Analogies of x-rays, jet travel, bananas, granite counter-tops, and the like are used, and are then in turn deconstructed to push a counter-argument. The UC Berkely Radiological Air and Water Monitoring forum was completely hijacked by this issue, to the detriment of all I would say.

It comes down to a question of statistics and probability. If people knew that, for example, 7% of the background radiation came from atmospheric nuclear testing, would it be a meaningful statistic? No, of course not. It only becomes mildly meaningful if you have the patience to delve into the science and the debate of the Linear Non-Threshhold model. If you've made it this far, however, your dread of nuclear power has been largely ameliorated.
 
Here is a recent quote from the South China Morning Post:

"Conditions in the unit 4 pool, 100 feet from the ground, are perilous, and if any two of the rods touch it could cause a nuclear reaction that would be uncontrollable," said Perrow.

"The radiation emitted from all these rods, if they are not continually cool and kept separate, would require the evacuation of surrounding areas including Tokyo," he said. "Because of the radiation at the site the 6,375 rods in the common storage pool could not be continuously cooled; they would fission and all of humanity will be threatened, for thousands of years."

I do not for a moment doubt that the conditions are perilous and that some of the rods will be distorted but I am skeptical that two of the rods touching "could" cause a nuclear reaction, I think the probability of that is so low it would be almost infinitesimal even if they touched for a significant time.

On the other hand I believe the chance of a fuel rod breaking while attempting to remove it is fairly significant and I would like to know what the consequences of this would be.

Also I would like to know how hot these rods are, some have been in the pool for many years and the hottest ones for around three years or so.

Is it true that their radioactivity increases for years after they are removed from the reactor? This does not make sense to me as I have also heard that they only need to be cooled for approximately 5 years before they are safe to put into dry cask storage.

There is so much disinformation out there it is getting difficult to seperate the real information from the noise.

I am very interested in these things since my wife and I have both been very sick with unkown ailments since the early summer of 2011, we are on Southern Vancouver Island and got hit fairly hard with the fallout from Fukushima that spring.

On the bright side our Sweet William Carnations that normally grow to be only 6 - 8" tall grew to 3' tall, quite incredible for anyone that knows flowers. And every year since they have grown the same, our neighbors have been asking for seeds as they've never seen the like before!

Is this all a coincidence, perhaps so, but the jet stream was comming from Fukushima to Van. Isle when the reactors blew and we had a lot of rain for a few days after the explosions and we were working outside preping the gardens during this time.
 
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It's just fearmongering. U4 pool conditions are not perfect, but also not terrible. They should be able to manage it.

It's a kind of thumb rule: if a source is continuously jumping around U4 pool then there is a good chance that it's just crap. U3 pool conditions - those are terrible: good chance that there are many (!) broken rods, with definitely damaged geometry and racks, with a heavy machinery is still lying on the top of the heap, and yet, there is no sign of ongoing recriticality.

About your questions:
- some broken rods would pollute the water in the pool, but it's very unlikely that they would cause any further problem.
- a rod while is underwater is not 'hot'. They has a heat output, continuously falling with time. This heat is removed by the water. If the heat is low enough to be removed by just air, then they can be extracted from the water. This is the 5 year limit you mentioned, however it's not a hard limit. Especially, because these rods will not go to dry casks, they will be moved to the common pool.
- the radioactivity of the used nuclear fuel is continuously falling with time.

Ps.: about your flowers and so: it's just coincidence. Our flowers have also changed, but some compost did the trick. However, if you want to control your fear, get a cheap dosimeter somewhere and check.

Ps2.: it was letucce season (spring) when we got some stuff from Chernobyl (as we are relatively close to the site and there was some fallout here), but nothing could be seen on the vegetables that year. I don't think that your flowers would be more sensitive.
 
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The problem with the U4 pool is that it had a "hot" core that had just been taken out of the reactor a short time before the earthquake.

It is also speculated that it burned for several days which if true would imply that the condition of some of the rods would be indeed less than perfect.

It's just fearmongering. U4 pool conditions are not perfect, but also not terrible. They should be able to manage it.

It's a kind of thumb rule: if a source is continuously jumping around U4 pool then there is a good chance that it's just crap. U3 pool conditions - those are terrible: good chance that there are many (!) broken rods, with definitely damaged geometry and racks, with a heavy machinery is still lying on the top of the heap, and yet, there is no sign of ongoing recriticality.

How long ago was the last core put into U3, and when was the last time someone went in to inspect it?

I do believe there are signs of criticality ongoing, are they not finding signs of short half life isotypes these days?


About your questions:
- some broken rods would pollute the water in the pool, but it's very unlikely that they would cause any further problem.

Exactely what I thought.

- a rod while is underwater is not 'hot'. They has a heat output, continuously falling with time. This heat is removed by the water. If the heat is low enough to be removed by just air, then they can be extracted from the water. This is the 5 year limit you mentioned, however it's not a hard limit. Especially, because these rods will not go to dry casks, they will be moved to the common pool.

Yes I understand this but if they are not kept submerged then they will get hot and burn, what I meant I guess with this question is not how hot they are per say, but how radioactive they still are?

If they were to drop one of the rods outside containment what would the consequences be, that is what I meant by how hot are they.


- the radioactivity of the used nuclear fuel is continuously falling with time.

Thank you, this is what I thought but some reports I've read say the radioctivity of the rods increase for 250,000 years which I thought to be ludicruse. Unless there was fissioning happening continuosly the rods would decay at their component materials half lifes once taken out of the reactor.

Ps.: about your flowers and so: it's just coincidence. Our flowers have also changed, but some compost did the trick. However, if you want to control your fear, get a cheap dosimeter somewhere and check.

Not scared, I already died once just over 5 years ago and it wasn't a big deal!

Just wondering, and I did not need to add any compost to any of my gardens, when I put them in 7 years ago I used plenty of Sheep, Cow and Chicken Manure, haven't needed to touch the soil since.


Ps2.: it was letucce season (spring) when we got some stuff from Chernobyl (as we are relatively close to the site and there was some fallout here), but nothing could be seen on the vegetables that year. I don't think that your flowers would be more sensitive.

It's fallout of course you wouldn't see anything, what would there be to see?

Also relative closeness to a Nuclear accident does not equate to how much fallout you recive, Vancouver Island and many other areas in North America got more fallout than many areas In Japan. The Jet stream carried it here.
Most of my plants were not affected and grew normally but the Sweet Williams went insane, I have no idea why.
 
but we want to know how much of what is considered "normal" now is a result of atmospheric testing and NPP accidents.
Your "want to know" isn't strong at all.
Who is banning you from reading, say, Wikipedia on this subject?
 
When you say that when measuring 100 Bq/kg is about the radioactivity of granite you ignore the fact that most organisms or intelligent people do not ingest granite nor will bio accumalation going up the food chain further concentrate it, unlike cesium, strontium etc.
Gosh.
Human body's natural radiation from K-40 and C-14 is around 70 Bq/kg.
There are some food products (nuts) with up to 400 Bq/kg of K-40.

This seems to confirm that general public is in dire need of educating.
 
By its nature, nuclear science defies easy understanding.
I don't think so.
I can summarize main facts about radiation, both natural and man-made, bombs, reactors and their accidents, into about a single page of text.

The difficulty lies in delivering this information to people.

Why news articles about "fish with N Bq/kg of Caesium-137 found" never accompanied with "for reference: seawater's natural radioactivity is ...; typical fish meat natural radioactivity is ..." snippets?
 

etudiant

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I don't think so.
I can summarize main facts about radiation, both natural and man-made, bombs, reactors and their accidents, into about a single page of text.

The difficulty lies in delivering this information to people.

Why news articles about "fish with N Bq/kg of Caesium-137 found" never accompanied with "for reference: seawater's natural radioactivity is ...; typical fish meat natural radioactivity is ..." snippets?
The XKCD cartoon strip (much read among IT geeks) had an excellent radiation on a single page summary. It includes some relevant background radiation data. See:
http://xkcd.com/radiation/

It was well enough received that the author placed it into the public domain.
 
The XKCD cartoon strip (much read among IT geeks) had an excellent radiation on a single page summary. It includes some relevant background radiation data. See:
http://xkcd.com/radiation/

It was well enough received that the author placed it into the public domain.
Thank you for that a very well formated and simple explanation.

I do not neccesarily trust Wikapedia as a source of information.

That is why I am here, to get the opinions of experts.
 
I do not neccesarily trust Wikapedia as a source of information.
Despite oft-repeated "Wikipedia is unreliable", it is a good starting point, especially on non-controversial subjects (why would anyone lie about e.g. half-life of I-131?). Wiki also has external links for more information, which can be used to verify the data.
 
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As I see that article is accurate in some details: but as the accurate pieces are seriously contaminated with many fear-mongering and lots of inaccurate speculation, it's inaccurate in the big picture it draws.

The author carefully selects the pieces of information fits with his preconception. That's not the way to write accurate articles.
 

etudiant

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mheslep

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Astronuc

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Caldicott's comment, “The problem is that TEPCO has hardly invited in the international community to help to try and solve the problem,” says Dr. Caldicott. “A huge company like [Florida-based engineering group] Bechtol, which makes reactors and is a very good engineering company, should have been invited in by the Japanese government to try and propose a way to deal with these problems in an engineering fashion,” or the statement attributed to her is incorrect.

Bechtel is a civil engineering and construction company based in San Francisco, although they have branches/offices in various locations. They do the civil/structural works at nuclear power plants, other power plants and process plants. They do not make reactors.

TEPCO has had foreign experts providing advice and assistance, although I do not know the specific outcomes of those interactions.
 
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I'm trying to understand a bit more about fission products of Fukushima Daiichi, their distribution as a result of the accident, etc. Specifically, I'm struggling to understand the details of Cesium 137 and Cesium 135.

The ANL Human Health Fact Sheet regarding Cesium (October 2001) mentions that both Cesium 135 and 137 are produced in relatively high yields of 7% and 6% (respectively). Yet Cesium 135 is rarely mentioned in soil or water analyses.

My questions are;
1. Shouldn't there be equally large amounts of Cesium 135 in the environment as there are of Cesium 137?
2. If so, does the comparatively low specific activity and energy yield of Cesium 135 mitigate its health risk to the point where it is negligible compared to the other radionuclides?
3. Or, is it the decay of Cesium 137 into Barium 137m that makes Cesium 137 so dangerous? (Again, meaning the health risk of Cesium 135 is negligible by comparison).

Any help in sorting this out would be appreciated.
 
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Since I'm in a confessional mood, I guess I should also admit I don't really understand how the various isotopes of cesium are produced: is it correct to say that Cesium 135 is the decay/daughter product of Xe135 (which itself is a fission product of U235), and that Cesium 137 and 134 are the direct fission products of U235?
 
I'm trying to understand a bit more about fission products of Fukushima Daiichi, their distribution as a result of the accident, etc. Specifically, I'm struggling to understand the details of Cesium 137 and Cesium 135.

The ANL Human Health Fact Sheet regarding Cesium (October 2001) mentions that both Cesium 135 and 137 are produced in relatively high yields of 7% and 6% (respectively). Yet Cesium 135 is rarely mentioned in soil or water analyses.

My questions are;
1. Shouldn't there be equally large amounts of Cesium 135 in the environment as there are of Cesium 137?
2. If so, does the comparatively low specific activity and energy yield of Cesium 135 mitigate its health risk to the point where it is negligible compared to the other radionuclides?
3. Or, is it the decay of Cesium 137 into Barium 137m that makes Cesium 137 so dangerous? (Again, meaning the health risk of Cesium 135 is negligible by comparison).
1 Yes
2 Yes. Cs135 specific activity is ~100 thousand times less than Cs137.
3 No, mainly it's reason #2 why Cs135 gets far less attention
 

mheslep

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1. Shouldn't there be equally large amounts of Cesium 135 in the environment as there are of Cesium 137?
After 15 yrs, half the 137 will be gone. Not so the 135.
 
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Shouldn't that be 30 years?
 

Astronuc

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Greenpeace - Radiation Along Fukushima Rivers Up to 200 Times Higher Than Pacific Ocean Seabed
http://www.ecowatch.com/radiation-fukushima-rivers-200-times-higher-than-pacific-ocean-seabed-1937971722.html

Riverbank sediment samples taken along the Niida River in Minami Soma, measured as high as 29,800 Bq/kg for radiocaesium (Cs-134 and 137). The Niida samples were taken where there are no restrictions on people living, as were other river samples. At the estuary of the Abukuma River in Miyagi prefecture, which lies more than 90km north of the Fukushima Daiichi plant, levels measured in sediment samples were as high as 6,500 Bq/kg.
It would be nice to have independent confirmation, but it makes sense that Cs (and other radionuclides) would find their way to rivers where they would concentrate in the sediment. Cs is more soluble in seawater, so it would be diluted much more rapidly.
 

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