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The more political thread besides Japan Earthquake: nuclear plants scientific one

by jlduh
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Dmytry
#91
May12-11, 11:54 AM
P: 505
Quote Quote by NUCENG View Post
It is not perfect
How much not perfect? Can you guess order of magnitude error % ?
It's a wonderful phrase, 'it is not perfect', applies equally to very accurate and very inaccurate estimates alike.
Drakkith
#92
May12-11, 11:54 AM
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Wasn't it what I implied when i said that radiation detectors do not measure in Sieverts?
Yep, which makes it all the more ridiculous that you then claim that we shouldn't use sieverts.

Actually, beta and gamma have same weighting factor. Bone marrow and skin, however, do not.
Correct, I meant to put Alpha's there, not betas.

it wouldn't be an accurate means of measuring potential body harm unless you actually calculated the conversion.
What they do, they report grays of external gamma exposure as sieverts of total exposure. It'll take actual measurements on the people's bodies to know their internal exposures, it depends greatly to diet and a zillion yet undetermined factors.
They, however, take the readings from a Geiger counter 'calibrated' in Sieverts (which is nonsense), and declare zone safe/unsafe based on that alone.
Why is calibrating a geiger counter to sieverts nonsense? Whether they did it in grays or sieverts it would end up being used for the same thing. It makes perfect sense to me how they can use it to declare a zone safe or unsafe since it is directly measuring the radiation in the area.
Susudake
#93
May12-11, 11:58 AM
P: 37
Quote Quote by pdObq View Post
You are contradicting yourself big time.
It may seem contradictory, but it's not.

You're saying then that there is no such thing as this complex I refer to? So going back to Eisenhower's use of the term (minus the academic/political connections, granted), it's all a chimera?

How about debating the point, that'll be much more convincing.
Drakkith
#94
May12-11, 11:59 AM
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Quote Quote by Dmytry View Post
How much not perfect? Can you guess order of magnitude error % ?
It's a wonderful phrase, 'it is not perfect', applies equally to very accurate and very inaccurate estimates alike.
Nothing is perfect. If you don't like it, too bad. The doses are estimated as best as possible using the available data. Whether you believe it is close enough to correct or not is irrelevant, as it is one of the few ways of getting the dose people have been exposed to.
jlduh
#95
May12-11, 12:00 PM
P: 468
Quote Quote by NUCENG View Post
http://www.epa.gov/radiation/federal/techdocs.html

Estimates require both the dose and the contributing isotopes for internal doses. See FGR 11 and FGR12 for explanations how this is calculated. For internal sources a whole body scan can make accurate measurements of body burden. Personnal dosimetry usually monitors external or whole body dose. Offsite doses are estimated based on monitoring results. It is not perfect but can be useful in making decisions about evacuation zones, and identifying people who may need medical followup.
thanks, so can you just answer this question (if possible by a no or yes answer as a minimum, but you can then elaborate of course):

do the measurements in mSv/h used by Japanese government, which are then compared to certain "limits" (like the 20 mSv /year for children now) to inform people (through the press for example) about "risks" and take decisions (eg evacuating, or removing soil, or whatever), do these specific measurements, the way they are done, with the equipment they use, take ALSO into account internal exposures through inhalation and ingestion of the various isotopes (mainly I-131 and CS-137 of course, but also Strontium as it appeared recently this one is also a concern?
Drakkith
#96
May12-11, 12:02 PM
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Quote Quote by Susudake View Post
It may seem contradictory, but it's not.

You're saying then that there is no such thing as this complex I refer to? So going back to Eisenhower's use of the term (minus the academic/political connections, granted), it's all a chimera?

How about debating the point, that'll be much more convincing.
I'll say it. There isn't some big complex that you refer to. It is a way for people who don't understand how things work to blame everyone else. Your statements were 100% contradictory, and the fact that you don't even realize it only makes it worse.
Dmytry
#97
May12-11, 12:36 PM
P: 505
Quote Quote by Drakkith View Post
Yep, which makes it all the more ridiculous that you then claim that we shouldn't use sieverts.
I'm saying that you shouldn't use numbers that are not in sieverts and call them sieverts. When you get 0.1 mSv in some medical procedure, rather complicated calculations have been done (it matters what tissues have been exposed).
When a geiger counter reads "0.01mSv/h" somewhere, it is extremely misleading. edit: Misleading both ways btw. Counter overcounts betas massively, so you can get a big scare when you find some mildly beta-radioactive crud, that'll make the counter click at insane rate, while the actual dose is much smaller than what it shows.
Why is calibrating a geiger counter to sieverts nonsense?
Because it (surprise surprise) doesn't even give you Grays accurate let alone Sieverts with the tissue type etc etc factors and internal exposure. and it does NOT convert betas correctly btw.
Whether they did it in grays or sieverts it would end up being used for the same thing. It makes perfect sense to me how they can use it to declare a zone safe or unsafe since it is directly measuring the radiation in the area.
sigh.
See, suppose we have two units. Centimetre, and biological centimetre equivalent, and there is a standard for the biological centimetre equivalent so that it depends to whenever you took your shoes off when you came home, to how often you take shower, and to what you eat. Then you see rulers, that by their very nature can only measure in centimetres, but they are labelled in biological centimetre equivalents.
Or better yet a fruit counter that counts apples, oranges, bananas, grapes, berries, watermelons, etc (it has some probabilities of missing grapes and berries depending to their size). You have it 'calibrated' in calories, and that is very misleading.
NUCENG
#98
May12-11, 01:51 PM
Sci Advisor
P: 916
Quote Quote by jlduh View Post
thanks, so can you just answer this question (if possible by a no or yes answer as a minimum, but you can then elaborate of course):

do the measurements in mSv/h used by Japanese government, which are then compared to certain "limits" (like the 20 mSv /year for children now) to inform people (through the press for example) about "risks" and take decisions (eg evacuating, or removing soil, or whatever), do these specific measurements, the way they are done, with the equipment they use, take ALSO into account internal exposures through inhalation and ingestion of the various isotopes (mainly I-131 and CS-137 of course, but also Strontium as it appeared recently this one is also a concern?
Yes, IF they are doing it correctly. Dmytry is discussing Grays and Sieverts and he is right that there is a distinction. A Gray is 1 J/kg of any substance. Sv are 1 J/kg equivalent dose. The links to FGR11 and FGR 12 explain whow a concentration of radiation in a cloud can be converted from Bq/kg, or Bq/cm^3 into an equivalent whole body dose in Sv accounting for inhalation, ingestion or simple external dose from the cloud, liquid, or contamination levels on surfaces. Limits for radiation workers, and the general puplic are expressed in Sieverts. In the United States we had limits on doses to the whole body, skin of the whole body extremities and there are also some guidelines for dose to thyroid and organs like bones and so on. The new standard now in use is TEDE (Total Effective Dose Equivalent). TEDE is the sum of Deep Dose Equivalent (Penetrating dose to the whole body) and CEDE (Committed Effective Dose Equivalent which is a combination of the internal effects of radiation to the organs.
Susudake
#99
May12-11, 02:19 PM
P: 37
Quote Quote by Drakkith View Post
I'll say it. There isn't some big complex that you refer to.
So since you've stated that there isn't, in contradiction to many others (try the google, it's pretty cool), it's a fact. Right.


Quote Quote by Drakkith View Post
It is a way for people who don't understand how things work to blame everyone else. Your statements were 100% contradictory, and the fact that you don't even realize it only makes it worse.
I could say the exact same thing back at you. I'll add that based on what we've both written, I've demonstrated the capacity to consider that any thing I say may is subject to clarification by others, while you've made equally or more sweeping statements without even supporting your contentions, it's all opinion. So we've made the same errors but only one of us is--upon being made aware of them--willing to admit that even to himself.

I refuse to get dragged further into such a "debate." I guess you'll have to ignore what I write or continue to be annoyed.

And as to some of these exchanges being less than civil, I'd say that the magnitude of the situation should excuse some passionate exchanges as long as both parties are acting in good faith. FWIW I think you are, I just think you a) have blinders on and b) are rhetorically out of your depth.

I hesitate a bit to go here but I will: having interacted with a lot of artists as well as a lot of scientists/engineers over the years, I've noticed something: the former tend to readily admit the limits of their knowledge and the efficacy of their non-scientific way of looking at things, and thus defer to scientists when the issues at hand are scientific, whereas scientists, especially engineers, tend to presume that they have superior intellects providing them unparalleled insight into all fields of knowledge and endeavor including those messy, non-scientific ones like politics, economics, social questions, etc.

Moreover, they tend to exacerbate the consequences of the limitations of their way(s) of understanding the world around them by demonstrating a moderate to severe lack of tact in debating others; the above is a perfect example.
Drakkith
#100
May12-11, 04:17 PM
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See, suppose we have two units. Centimetre, and biological centimetre equivalent, and there is a standard for the biological centimetre equivalent so that it depends to whenever you took your shoes off when you came home, to how often you take shower, and to what you eat. Then you see rulers, that by their very nature can only measure in centimetres, but they are labelled in biological centimetre equivalents.
Or better yet a fruit counter that counts apples, oranges, bananas, grapes, berries, watermelons, etc (it has some probabilities of missing grapes and berries depending to their size). You have it 'calibrated' in calories, and that is very misleading.
Bad comparison. The detector can easily be set ahead of time to predetermined parameters to make it into sieverts. And even IF the settings are a little off, you can easily determine the real sieverts if you need to by taking the values you got off the detector and plugging in additonal data.

I'm saying that you shouldn't use numbers that are not in sieverts and call them sieverts. When you get 0.1 mSv in some medical procedure, rather complicated calculations have been done (it matters what tissues have been exposed).
Yes, and that value will have different weight in the formula depending on the parts of the body that have been imaged. However, in the field you are looking at a total body exposure. Will it be as exact as a medical scan? Probably not. But the radiation isn't hitting one body part like a medical scan is, it is hitting all of you.

Because it (surprise surprise) doesn't even give you Grays accurate let alone Sieverts with the tissue type etc etc factors and internal exposure. and it does NOT convert betas correctly btw.
You can easily find the grays by reversing the formula you used to put the geiger counter in sieverts. And why doesn't it convert beta's correctly?

So since you've stated that there isn't, in contradiction to many others (try the google, it's pretty cool), it's a fact. Right.
Not in the way you are referring to it there isn't.

FWIW I think you are, I just think you a) have blinders on and b) are rhetorically out of your depth.
So? I don't care what you think about me.

I hesitate a bit to go here but I will: having interacted with a lot of artists as well as a lot of scientists/engineers over the years, I've noticed something: the former tend to readily admit the limits of their knowledge and the efficacy of their non-scientific way of looking at things, and thus defer to scientists when the issues at hand are scientific, whereas scientists, especially engineers, tend to presume that they have superior intellects providing them unparalleled insight into all fields of knowledge and endeavor including those messy, non-scientific ones like politics, economics, social questions, etc.
I've interacted with plentry of people as well. Most of them that DON'T have at least some small amount of scientific mindset don't have a clue how the world actually works. They tend to spew things such as "The government/big business/whatever they dont trust, is out to get them and everyone else and is evil or incompetent and can't ever be trusted at all".

Moreover, they tend to exacerbate the consequences of the limitations of their way(s) of understanding the world around them by demonstrating a moderate to severe lack of tact in debating others; the above is a perfect example.
Probably because of the difficulty in keeping tact for years of people who don't understand a word of what comes out of their mouths.

I could say the exact same thing back at you. I'll add that based on what we've both written, I've demonstrated the capacity to consider that any thing I say may is subject to clarification by others, while you've made equally or more sweeping statements without even supporting your contentions, it's all opinion. So we've made the same errors but only one of us is--upon being made aware of them--willing to admit that even to himself.
Nonsense, if I make a statement that is 100% about something that is immune to opinion, such as facts, numbers, ETC, and I'm incorrect, then I will immediately admit my mistake when I am made aware of it. The problem here is that 99% of this thread ISN'T about those kinds of things. It's about opinions. Even the title of the thread screams opinion.
jlduh
#101
May12-11, 04:38 PM
P: 468
Back to a fact (i will express no opinion )

35 Japanese reactors are soon to be out of line

http://www3.nhk.or.jp/daily/english/12_29.html

All told, 35, or about two-thirds, of Japan's commercial reactors will have been shut down by the end of May.

During the next few months, 5 more reactors will have to be shut down ahead of regular inspections.

If the utilities decide to keep these 40 reactors offline for the time being, Japan will have about 75 percent of its reactors shutdown this summer.
jlduh
#102
May12-11, 04:47 PM
P: 468
and an other fact (but it's more for getting lighter here, even if the reality behind it is not fun for people concerned): the procedure for citizens to get compensation from Tepco seems as clear as their strategy for restoring the mess:

http://www.tepco.co.jp/en/nu/fukushi...ges/flow-e.pdf

I wish good luck to these unfortunate people...
Dmytry
#103
May12-11, 04:55 PM
P: 505
Quote Quote by NUCENG View Post
Yes, IF they are doing it correctly. Dmytry is discussing Grays and Sieverts and he is right that there is a distinction. A Gray is 1 J/kg of any substance. Sv are 1 J/kg equivalent dose. The links to FGR11 and FGR 12 explain whow a concentration of radiation in a cloud can be converted from Bq/kg, or Bq/cm^3 into an equivalent whole body dose in Sv accounting for inhalation, ingestion or simple external dose from the cloud, liquid, or contamination levels on surfaces. Limits for radiation workers, and the general puplic are expressed in Sieverts. In the United States we had limits on doses to the whole body, skin of the whole body extremities and there are also some guidelines for dose to thyroid and organs like bones and so on. The new standard now in use is TEDE (Total Effective Dose Equivalent). TEDE is the sum of Deep Dose Equivalent (Penetrating dose to the whole body) and CEDE (Committed Effective Dose Equivalent which is a combination of the internal effects of radiation to the organs.
But how accurate are those estimates? We all know them are imperfect; nothing is perfect; and so on and so forth. In science, each number has error range.
When you say it is imperfect, please tell how much do you think it is imperfect. The "imperfect measurement" is a tautology.

In my opinion it's at best 'within same order of magnitude' sort of estimate. The dose near a rain drain can be order of magnitude higher than average [not as dramatically as in the video where Geiger counter is counting betas, but still quite dramatically thanks to inverse square law], the long term inhalation (of the deposited material that re-enters air) is very dependent to the weather, etc. The doses that kids can get, well, god knows, kids play in dirt, some types of dirt chemically absorb Cs-137, some do not. The distribution of radioactivity is a fractal with high 'roughness', there's huge variability down to 1m distances.
Then the food testing, beyond limit food will slip through occasionally [you cant test everything, just randomly chosen samples], how often? How do you know in advance how often? And what is the distribution of the doses? Then, there's the issue of wood ashes... do they use wood for heating at all or not? In the tsunami aftermath? Then there's the issue of the wreckage cleanup work that has to be done. And so on and so forth, and that's the things that i'd guess can change dose by more than factor of 2, and there's probably a lot of other important things I missed. The contamination level of radioactive boars in EU varies immensely - a few boars are heavily contaminated, most are harmless [strongly non-gaussian distribution btw], not a good situation for random sampling based testing.

It is not enough to calculate 'to the best of your knowledge' in science. You need also to provide the error range, and ideally distribution of the errors. In engineering too - I believe you do have ranges for uncertain numbers?

re: Sievert vs Gray, it just irritates me immensely to see a Geiger counter that advertises it's giving out Sv. The bloody thing doesn't even do Grays on gamma very well, the thing overcounts betas - yet it proudly says microSieverts/hour.
Drakkith
#104
May12-11, 05:00 PM
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Quote Quote by jlduh View Post
Back to a fact (i will express no opinion )

35 Japanese reactors are soon to be out of line

http://www3.nhk.or.jp/daily/english/12_29.html
Interesting. Hopefully they will fix any issues before they come back online. (If they are going to that is.)
jlduh
#105
May12-11, 05:06 PM
P: 468
More contamination on the grass in towns outside of the evacuation zone, and far outside!

http://www3.nhk.or.jp/daily/english/13_01.html

3,480 becquerels of radioactive cesium were detected in one kilogram of pasture grass collected on May 5th in Nikko City, Tochigi Prefecture. The figure exceeds the state limit of 300 becquerels. Also, at two different locations in Nasushiobara City, 3,600 becquerels and 860 becquerels of radioactive cesium respectively were detected in one kilogram of pasture grass collected on May 3rd.

Tochigi Prefecture requested farmers in the area where the radioactive substance was detected not to feed pasture grass to livestock.
NOTE THAT NIKKO CITY IS AT AROUND 170 kms FROM THE PLANT (SOUTH WEST) which is quite far... the other one is at around 100 kms same direction.

http://maps.google.com/maps?f=q&sour...696167&t=h&z=8

It seems that the winds are spreading the bad stuff in several directions, the North west has been severely touched, the South West could start to get the same scenario.

Over a long period of time (who knows when this crisis will be contained), we can fear that long life Cs-137 (ans maybe Strontium?) will accumulate here and there, like thin layers of small snow falls which would never melt and add weeks after weeks...

The only difference being this is invisible and dangerous snow...
Drakkith
#106
May12-11, 05:11 PM
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re: Sievert vs Gray, it just irritates me immensely to see a Geiger counter that advertises it's giving out Sv. The bloody thing doesn't even do Grays on gamma very well, the thing overcounts betas - yet it proudly says microSieverts/hour.
I understand. But the issue isn't that it reads in microSieverts/hour. ANY measurement system will be just as accurate on that device as any other one. The key, I believe, is to make it as accurate as possible.

But how accurate are those estimates? We all know them are imperfect; nothing is perfect; and so on and so forth. In science, each number has error range.
When you say it is imperfect, please tell how much do you think it is imperfect. The "imperfect measurement" is a tautology.
And? The fact is that the system is in use and it works, whether you agree with how accurate it is or not. Is there another way of doing it that works better in that situation?

Your entire post goes off on a tangent about things that aren't remotely close to dealing with counting sieverts on a geiger counter. Do you really think that they never took any of your situations into account when they designed the system and when they use it? Ludicrous!

You might not like the fact that there are error ranges and estimates and such, but in the end it doesn't matter. There isn't any other way of determining these things.

And just to make sure everyone knows my position, I'll say it again.

I think there were serious mistakes made in the running of the NPP's in Japan. I think there are currently and will be more mistakes made everywhere. But my opinion is that the gain is worth the risk as long we err more on the side of caution than we have in Japan.
Dmytry
#107
May12-11, 05:20 PM
P: 505
Drakkith: What I do not like is that nobody is calculating or reporting the error ranges. There is an other way. Honest science. Where not only you tell the measurements, but you also tell how much (and how often by how much) it can be wrong.
Other thing that I do not like is this nonsense discussion where any error - be it off by up to an order of magnitude, be it to 1% tolerance, is equally 'imperfect'. You just don't distinguish between any degree of 'imperfect', and for you it makes absolutely no difference, it's all verbal reasoning from you, is it not? Yes/no, perfect/imperfect (and everything is imperfect), etc.

"Do you really think that they never took any of your situations into account when they designed the system and when they use it? Ludicrous!"
Do I think they haven't took any? No, they have, some of. Do I think they have took ALL ? No I don't! It is immense amount of work. It is just not doable, period. What is doable though, is a honest estimation of by how much it can be wrong. Hell, even a dishonest estimation of the error range is still a huge step forward compared to 'throw some numbers out and assure them that it is the best measurements that can be done'.

"But the issue isn't that it reads in microSieverts/hour. ANY measurement system will be just as accurate on that device as any other one."
Suppose you had a ruler that reads in calories, you measure size of the fruit with it. Well, the distance measurements on that ruler can be accurate, but the calorie on that ruler are not. You can, however, use the ruler that reads in centimeters (or inches), with a conversion table (for different fruits), to obtain calories far more accurately.
unlurk
#108
May12-11, 06:08 PM
P: 72
jlduh, I have no interest in joining this thread.

I'm interested in the technical aspects of Fukushima, not the politics.

As such there are aspects of Fukushima that might be compared to Three Mile Island or Chernobyl or SL1 or any number of sites or events.


I only wondered if that documentary was considered a "fringe" video made by nutjobs or not.

You are living in France so I thought you might have some knowledge of the subject matter.

BTW
2, 3 and 4 are each spewing steam at the moment.


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