There’s a lot of discussion of radiation from the Fukushima plants, along with comparisons to Three Mile Island and Chernobyl. Radiation levels are often described as “<X> times the normal level” or “<Y>% over the legal limit,” which can be pretty confusing.
Ellen, a friend of mine who’s a student at Reed and Senior Reactor Operator at the Reed Research Reactor, has been spending the last few days answering questions about radiation dosage virtually nonstop (I’ve actually seen her interrupt them with “brb, reactor”). She suggested a chart might help put different amounts of radiation into perspective, and so with her help, I put one together. She also made one of her own; it has fewer colors, but contains more information about what radiation exposure consists of and how it affects the body.
I’m not an expert in radiation and I’m sure I’ve got a lot of mistakes in here, but there’s so much wild misinformation out there that I figured a broad comparison of different types of dosages might be good anyway. I don’t include too much about the Fukushima reactor because the situation seems to be changing by the hour, but I hope the chart provides some helpful context.
(Click to view full)
Note that there are different types of ionizing radiation; the “sievert” unit quantifies the degree to which each type (gamma rays, alpha particles, etc) affects the body. You can learn more from my sources list. If you’re looking for expert updates on the nuclear situation, try the MIT NSE Hub. Ellen’s page on radiation is here.
Lastly, remember that while there’s a lot of focus on possible worst-case scenarios involving the nuclear plants, the tsunami was an actual disaster that’s already killed thousands. Hundreds of thousands more, including my best friend from college, are in shelters with limited access to basic supplies and almost no ability to contact the outside world. If you’re not sure how to help, Google’s Japan Crisis Resource page is a good place to start.
Edit: For people who asked about Japanese translations or other types of reprinting: you may republish this image anywhere without any sort of restriction; I place it in the public domain. I just suggest that you make sure to include a clear translation of the disclaimer that the author is not an expert, and that anyone potentially affected by Fukushima should always defer to the directives of regional health authorities.
xkcd 
@pauls:
Did you read either the entire IAEA brief or the entire radiation chart? Take the highest amount from your data (170 uSv), multiply it by 24 (for daily dosage), and you end up with 4080 uSv, or 4.08 mSv. There’s a segment on the chart that claims ~3.6mSv for some areas. Just because the range is from 3-170 uSv per hour doesn’t mean that the “average” isn’t 3.5 uSv. What is meant by average? Mean, median, mode? I would argue that using arithmetic mean for “average” is very misleading in this context, and that median (you could even make an argument for mode) is much more appropriate. Maybe Randall could have been a bit more descriptive with what he meant when he used the word “average,” but I don’t really think we can put him under any obligation to do so.
Here’s the few paragraphs preceding and following Paul’s:
“In some locations at around 30 km from the Fukushima plant, the dose rates rose significantly in the last 24 hours (in one location from 80 to 170 microsievert per hour and in another from 26 to 95 microsievert per hour). But this was not the case at all locations at this distance from the plants.
Dose rates to the north-west of the nuclear power plants, were observed in the range 3 to 170 microsievert per hour, with the higher levels observed around 30 km from the plant.
Dose rates in other directions are in the 1 to 5 microsievert per hour range.”
Source: http://www.iaea.org/newscenter/news/2011/fukushima170311.html
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Folks should ignore the factually incorrect and misleading chart above.
Instead the following link is to a site which actually does a careful analysis. When it makes comparisons, it does an apples-to-apples comparison instead of the sloppy analysis of the chart.
A Layman’s Intro to Radiation
http://people.reed.edu/~emcmanis/radiation.html
When trying to understand the numbers, look at the link above. The chart is crap.
What’s wrong with the chart?
1) When scaling between colors, it just adds single incident doses to dose rates — nevermind that one is a dose and the other a rate. If it wants to do this kind of addition, it should settle on a dosage time (an hour, day, year. whatever and then use this accumulation time throughout so that comparisons are meaningful).
2) The chart reports at least dose rate that is just plain wrong by a factor of 24. There are probalby other such mistakes.
3) It reports an ‘average’ dose rate in a situation where using an average can be very misleading:
(a) First of all, I think the ‘average’ it reports is just pulled out of thin air; i.e. it is not a true average weighted by population or land area or number of villages. Instead it appears to be the lower limit of a large range of values. As such, it isn’t an average at all and is pretty meaningless.
(b) Even if the ‘average’ has some basis in reality, fallout deposition is very spotty. A lethal dose could be depositved in one place, while all surrounding areas have only elevated radiation levels. Estimating health risks based on an average in this situation covers up the fact that there are some areas which could pose a serious risk.
Forget the chart. It is disinformation.
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Am I being punked? You do realize that this chart is made by a friend (?) of the author of the chart you’re bashing, and that he based most of his data off of it? Ashton? Is that you?
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@PianoTuner
Yes, I read the chart and the IAEA report. That’s why I find the chart so misleading that it should be disregarded.
Re: the 3.65mSv in the chart:
Randall’s mistaken 3.5 uSv ‘daily’ dose is purportedly for an ‘average town’. The 3.65mSv ‘daily’ dose in the chart is purportedly the dosage received at the reactor site. The reactor site is not an ‘average town’, so this is not where Randall carries the ‘town’ dose from blue to green.
Now I assume that representing doses as chart areas is supposed to enable a visual comparison to give us an easy way to put exposures in perspective. A good idea. I like it. Unfortunately this idea is very badly executed in the chart:
If Randall wanted the blue to represent daily exposures so we can compare the importance of different sources, then all blue areas should represent daily exposures. Instead, we have a ‘daily’ exposure (in reality hourly exposure) for the ‘average village’ mixed in with several annual doses.
If the chart accurately portrayed its purported ‘average town daily exposure’, the area representing this would be 24X the size that appears now in the chart.
Same problem with the green area. Randall should settle on, say, annual doses for green and then calculate annual doses for sources he wants to compare in the green area. Had this been done accurately, the blue daily doses carried over to green would not be three tiny green boxes, but instead the number of tiny green boxes for the blue exposures would be:
(3.5*24+10)*365/20=1715
Ya know, there’s a big visual difference in the chart between 3 and 1715 boxes meaning even the purported town expousure is not at all apparent from the chart as-is.
Keeping in mind that the purported ‘average town’ dose is very probably not an ‘average town’ dose at all and instead is low by a lot for a number of towns, then the green area attributed to reactor fallout would be even larger and certainly exceed the annual nuke worker limit — sometimes by a lot. The chart as-is does not even hint that this is the case.
If the 3.65 mSv daily exposure Randall reports at reactor sites were accurately portrayed for comparison to the annual allowed nuke worker exposure, this would be done with:
(3.65 mSv*356)= 1.3 Sv
and
1300000 uSv/20uSv per box = 64970 green boxes
I.e. the annual exposure at the plants themselves is 1.3 Sv and >20X the annual exposure limit for a nuke worker. This is not at all apparent from the chart as-is.
Since the chart that is supposed to put exposures in perspective fails to do so in at least two important instances, I’m sticking with my judgment that the chart is very misleading and crap.
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@piano
I’m a geezer and not someone jerking your chain. I’m sorry to slam Randall so hard, but this is an important issue and information about it should be presented accurately.
Since the chart has been picked up and advertised widely — and apparently uncritically — by those who represent themselves as authorities in science, I don’t want to leave this unchallenged.
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@Rinky
Rats! I wanted to get in on the $50 bio half-life thing. BUT since you cleared up an question I’ve had about whether dosages in Sieverts take into account ingestion effects or not, I’ll not ask for a slice of the $50.
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@pauls
Don’t leave it unchallenged, but read the chart carefully. Green section, bottom left, second from the bottom.
“One-day dose (~3.6 mSv) at two sites 50 km NW of Fukushima on 3/16 seen again on 3/17.”
I think you’re expecting the chart to read differently than it does. The way I interpret it (and I believe the main idea that Randall is trying to get across) is “wow, some of the hardest hit areas are receiving daily radiation similar to that absorbed when getting a mammogram. That’s not great, but it’s not Chernobyl.”
I can tell from reading your posts that you want the chart to read a certain way, but wishing won’t make it so. If you take some time to get yourself accustomed to the way the data is laid out, it is indeed consistent, informative, and accurate within the reasonable limits it claims. If you don’t like the layout, make your own version that conveys the message YOU want to convey, but this one does fine for me.
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@pauls:
You seem to be mixing your millis and micros pretty liberally. Recognize that there are three orders of magnitude between µSv and mSv.
You also seem to think that the workers will never leave the plant, and exposure will never drop. If the workers are only at the site for 12 hours a day, sleeping in an uncontaminated area, seven days a week, that number instantly drops by half. If they are cycled out after working for three months without a day off, it drops another three quarters. If the plant conditions change, better or worse, the exposure also changes.
I do agree that does and dose rates are mixed poorly, and that the time period on dose rates should be standardized. I just can’t figure out a way to meaningfully standardize ‘annul dose limit’ (which isn’t 12x a “monthly dose limit”- it is allowed to be all at once) with “standing next to Chernobyl during the meltdown”. Changing most of them to hourly doses, and bolding the exceptions, would probably work best.
‘Average’ can certainly mean lots of things. I suggest the area method: Generate one field representing town density by geographic area. Generate another of dose rate by geographic area. A third, the quotient of dose rate and town density, by geographic area (units of dose rate*area/town). Integrate the third across the entire zone of concern giving you a value in (Dose rate/Town). Or you could find the dose rate that has the lowest sum of differences of squares, considering all the towns, or you could just plot all the points and guess at the densest point on the plot.
Radioiodine exposure is indeed mitigated by distance: the concentration of radioiodine drops off with (very roughly) the fourth power of distance; said iodine must fill the volume affected, so concentration of iodine will drop with the cube, and the percentage of iodine which is radioactive with drop of logarithmically with time, and it must travel from the source to the victim; for three or fewer half-lives, the rate of decay will remain on the same order of magnitude, and for more than three half-lives the dose will be negligible. Over the area of concern, decay is roughly linear. Concentration of radioiodine, then drops linearly faster than total iodine, for fourth power reduction by distance from the source.
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I think the EPA got days for hours mixed up.
http://journals.lww.com/nuclearmed/Abstract/2001/04000/Iodine_131_Ablation_Therapy_for_a_Patient.4.aspx
100 hours for Iodine fits my clinical experience too.
PS as asked before can anyone tell me which reference the “lowest 1 year dose clearly linked to cancer 100mSv” comes from?
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Extremely disappointed that not one but BOTH these purported scientists don’t appear to know any better than to cite a wikipedia page as a source.
Must I say it? Nothing on WP is cite-able, unless it is referenced with a citation, at which point cite the source. Randall makes cartoons, guerrilla art, and philosophy – not much to risk there; but a shortage of judgment on Ellen’s part could create an actual problem.
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The biological half-life of radioiodine is indeed shorter than the biological half-life of iodine. I noted that the KI pills are claimed to be good for only 48-72 hours; I conclude that the biological half-life of iodine is on the order of days.
I also note that without fission, the rate of production of radioiodine is trace, so the proportion of radioiodine in the (I don’t think yet released) plume is decreasing already.
I was going to make a joke about the decay of Xe-135 reducing negative reactivity, but realized that the news networks would not detect the sarcasm and might report it as an actual threat.
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I’m a little puzzled by how the “EPA yearly limit on radiation exposure” (1 mSv) can be less than a third of “normal yearly background dose” (3.65 mSv). Can anyone explain what’s going on there?
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@jp
The short answer? They are way overcautious.
EPA allowances are ridiculously low for radiation workers, and they are even more stringent for the general public. The number you state is for the general public, not for radiation workers. A maximum yearly limit for radiation workers is 50 mSv. The exposure limit for a pregnant radiation worker (5 mSv) is half of what you get from an MRI (10 mSv).
How do I know this? I am a certified industrial radiographer. And for the record I have, at one point during my career, been pregnant. My boss precluded the limits completely, however, by not letting me participate in X-rays during my pregnancy AT ALL. I had to block off the parking lot instead 😦
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@Piano
Yes. I absolutely want the chart to be constructed differently.
If there are two areas of green and one is larger than another, I want the larger area to represent a larger esposure and proportionally so. I want it to be constructed this way because that’s the way most people will read the chart.
As it is now, one green area, for instance the Chernobyl ground zero green area, actually represents ~2628000 times more radiation than another green area, for instance the annual nuke worker exposure yet the Chernobyl area is approximately 1/8 the area of the worker annual limit. This is very misleading.
My other two gripes still stand: 1) The number used for exposure in an ‘average town’ in the Fukushima area of Japan needs explanation — where does this come from? 2) If it is what I think it is, it is low by at least a factor of 24 which makes this an important and misleading mistake.
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@ViviWannabe
It’s not so much that they’re (obviously) being overly cautious that confused me as that meeting their ‘yearly limit’ is a practical impossibility, short of spending more than 2/3 of one’s life in radiation-proof clothing. Would a more reasonable statement of what the EPA limit is actually trying to say perhaps be yearly limit on radiation exposure to a single member of the public from sources OTHER THAN inescapable background exposure?
I do see your point about the limits being rather ridiculous though. One wonders what your boss would have recommended had you broken a bone during your pregnancy.
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It would be interesting to compare this data with chemical cancirogens that are around us like dioxins.
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The yearly limit for anything is measured *in addition* to the background dose. A control measurement is performed somewhere that will have comparable background and be free from extra radiation, and compared to a sample from somewhere suspected to have potentially higher radiation. This procedure is audited both internally and by the NRC for completion, thoroughness, and quality.
For example, at Reed, we measure the concentration of radionuclides leaving the ventilation stack to assess our compliance with the EPA’s regulations. We do this with a detector that measures the radioactivity of particles on a filter as well as a detector which measures the radioactivity of gases passing through it. The detectors each have a twin which sits outside the flow of air from the reactor room, measuring the background at that spot. The readings we record are based on this subtraction. (For the curious, they are on the order of 10^(-11) uCi, and rarely distinguishable from background at all).
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@ViviWannabe
Did you mean to reference radiation exposure from a CT scan, rather than an MRI scan, which doesn’t involve any exposure?
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@ViviWannabe
I’m puzzled. How do you get 10 mSv exposure in an MRI? Are you confusing this with a CT scan?
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@Decius
I absolutely know the difference between millis, micros as well as hours, days and years. It’s because I do understand these that I have problems with the chart. As for exposures to workers at the plants, I made no statements nor assumptions about them. Instead my criticism is and was the way the chart represents the intensity of radiation near the plants.
Let me use piano tuner’s response above to illustrate my complaint:
Piano tuner notes that the green area for the mammogram and green area representing the radiation for two sites with daily dose rates of ~3.6mSv are roughly the same size. Visually these sit next to a much larger green area representing the annual dose for a nuclear worker.
Constructed this way, the visual impression is that the dose for a mammogram is comparable to the dose received at the two sites from fallout, but both of these doses are much less than the annual dose allowed for a nuclear worker, so piano tuner’s takeaway was this:
“wow, some of the hardest hit areas are receiving daily radiation similar to that absorbed when getting a mammogram. That’s not great, but it’s not Chernobyl.”
Now if it were me, I’d say:
“wow, two sites 50 km distant from the reactors – i.e. well outside the 30km controlled zone – were (are?) so contaminated that people living at those sites were (are?) receiving radiation at rates (365*3.6/50)= 26X the annual allowed dose for nuclear workers.”
If the chart were properly constructed, my conclusion which I humbly think is the more relevant conclusion would be abundantly apparent. Instead, the magnitude of the radiation at the 50 km-distant sites is masked by the chart.
That pretty much sums up my overall beef with the chart: it is very misleading.
My other beefs, however, still stand:
1) Just where does the number offered for ‘average town’ exposure in the Fukushima area come from?
2) If it is what I suspect is, then it is off by at least 24X making this an important and misleading mistake.
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@ellen
Thanks for the information on your website. You cleared up the questions I had about internal and external exposures and how these relate to radiation levels reported in Sieverts.
What’s not so clear is that in order to calculate a detected dose in Sieverts, the radionuclide mix needs to be known. Strikes me that detectors that measure quantitatively the radionuclide composition of radiation would be pretty sophisticated and not likely to be widely deployed in civilian areas. If this is hte case, what assumptions are behind the radiation reports for fallout in Japan?
Thanks, if you find time to answer.
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This is exactly the kind of info that I have been looking for in media (without success). It does need some background knowledge and careful reading not to misinterpret at points, but the reality is complex so I think we have to live with that!
@jb and @ViViWannabe: The EPA limits is of course the limit of radiation exposure emanating from the technical stuff they are concerned about. So it is quite natural that they can be lower than the background exposure.
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@Paul
Determining the radionuclide mix is actually not that hard, and pretty useful/required for things beyond accident conditions. Waste disposal, for one.
The detector problem is solved by simply recovering a sample and bringing it to the detectors. If something is contaminated, you should be able to break off/scoop up/wipe off a bit of that contamination. The ones I’m most familiar with are high-purity germanium (HPGE) detectors used for gamma spectroscopy. You take your sample, put it in the detector (large, cooled with liquid nitrogen, extremely high voltage applied across the detector), and the energy of the gamma rays coming off the sample tell you what nuclides are present in the sample. At my facility, we use this technique for neutron activation analysis, a nondestructive way to determine the elemental composition of a sample.
Power plants have these detectors on site for sure — that’s where we got ours, from the Trojan plant when they decommissioned. They’re useful for operations because they’ll let you know where contamination originated as well as how long it will stick around.
For an example of how these are used, take a fuel leak at my reactor (it sounds scary, but the worst one we’ve had resulted in an emission that was only 10% of what was allowable for *normal* operations, and we just improved our fuel so it shouldn’t happen again). We detect the leak when our air monitors alarm, informing us of elevated levels of radioactive material in the air we’re releasing to the environment. The ventilation system automatically changes configuration, filtering the released air and lowering the volume of air released. The reactor is shut down, and the filters from the particulate air monitors replaced. The filter is then counted with one of the gamma specs, which shows cesium and rubidium (produced by decay of xenon and krypton). We then conclude it was a fuel leak that produced the readings, make required phone calls, and prepare for a frustrating few weeks of find-the-leaker operations.
That same filter could be used to detect a leaking sample (we find the nuclides expected by the experimenter in the air) or a faulty detector (count filter…nothing found). The detectors do also come in more portable, less accurate versions, which can be used in a pinch.
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@paul
Isn’t the problem you have with the values from Fukushima that one is the average value from all measurements in the area and the other are peak values.
I agree that it would be very interesting to get more info about how measurements are done, but let’s assume that they know what they are doing and the values reflect the real situation. In that case we have a situation were radiation levels in general in the area are pretty low, but at points gets much higher for a limited amount of time. either because of downfall of radioactive nucleotides of Iod and/or Cesium or just by clouds containing radon etc passing by.
I know from my home town in Sweden which got quite a lot of Cesium from Chernobyl, that the downfall was very localized. Unfortunately a lot in my favourite mushroom forest 😦 But the exposure from that is still much less than that from my own house that gives off radon from the bricks 😦
And regarding your opinion that the sizes of the rectangles are misleading – well I don’t agree. If you are a power plant worker you will probably work there for years, so it is relevant to talk about yearly dosis. To give the value for a town near Fukushima for a year wouldn’t be relevant. The values changes day by day and if nothing new happens they will drop a lot within a few days as most of the nucleotides are short lived.
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@ellen
Thanks for the detailed explanation. It’s been a few years (okay decades) since I did physics, so it’s fun to exercise my remining synapse.
I’ve torn pretty heavily into Randall’s chart. I hope this hasn’t been too offensive. The idea behind it is great and needed, but since it’s been picked up by some high-profile blogs, I wish it were a little more rigorously done.
Anyway, thanks.
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@robert
My problem with the ‘average’ value reported in the chart is I have no idea how that was calculated and what it represents — if it was calculated. Also, I suspect it is an hourly and not daily dose rate which makes it wrong by a factor of 24 which makes a big difference in the interpretation of whether fallout in this area is serious or not.
As for my question to Ellen on how radiation levels are calculated, I wanted to know a bit about the technolgy because 1) I wanted to know and 2) knowing how things work gives insight into how they might not work. Ellen gave an excellent answer to this, BTW.
As for misleading area sizes, we’ll have to disagree. I’ve pretty much spelled out the reasons in earlier posts.
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@ JerryB
The only citation from Wikipedia is the definition of a Sievert. This is a good way for everyday people to understand the basis. The other sites contain the real information. There is no scientific non-sense in that, just accessibility.
And for physical definitions, Wikipedia is really great and exact (for simple cases and general informations).
Great Chart
He!
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Not that this is terribly relevant here, but since radiation levels in Japan and those in Chernobyl were compared and concluded to be very different, here is a link to pages updated daily showing where and what is blowing in wind. (Cool movie at bottom of page. Also notice how lucky it is that most of the time the wind is seaward.)
http://www.zamg.ac.at/aktuell/index.php?seite=1&artikel=ZAMG_2011-03-24GMT11:24
Here is the English translation of the page above with estimates of I-131 and Cs-137 source strengths in the first four days of reactor troubles in Japan with comparisons to overall Chernobyl emissions of I-131 and Cs-137.
Click to access Japan2011-03-22_1500_E.pdf
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@JerryB
Maybe you looked at Ellen’s chart at a different time from me, but I see that six of her eight citations come from non-Wikipedia sources. One of two Wikipedia citations is merely a figure on how much radiation comes from a banana. The other is on acute radiation sickness, and she has another supporting citation for that topic. You claim that “nothing on Wikipedia is cite-able, unless it is referenced, at which point cite the source.” The Wikipedia articles she cited had 16 and 30 references, respectively. Maybe she should have cited the original sources, but attacking her for that approaches saying that strict academic rigor (APA, MLA, whatever you choose) should be used for anything that anybody produces for public consumption. Yet, her chart wasn’t for publication in a journal; it was for basic education purposes, and I think it got the job done.
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OK, I found a reference for the biological half life of Iodine:
http://www.epa.gov/rpdweb00/radionuclides/iodine.html
This gives the biological half life of iodine as about 100 days for the body as a whole, significantly less in bones, kidney, spleen, and reproductive organs. Note that this half life only counts iodine that is actually incorporated into an organ. Excessive iodine is passed through urine. This is probably why the iodine pills are only good for a few days — the excess amounts are not stored in the body, so they pass quickly.
@pauls: I agree with you to an extent: The chart tries to present a lot of information, and (unintentionally, I believe) blurs the line a little bit between short and long-term exposures. To people who don’t pay attention and fully read the chart, they may misunderstand. However, it wouldn’t be reasonable to annualize the doses that have been observed at and around the reactor, as no-one reasonably expects those doses to remain constant (or grow). Thus, people aren’t going to get exposures that large.
Also, you said: “wow, two sites 50 km distant from the reactors – i.e. well outside the 30km controlled zone – were (are?) so contaminated that people living at those sites were (are?) receiving radiation at rates (365*3.6/50)= 26X the annual allowed dose for nuclear workers,” but as has been pointed out, the max annual allowed dose can be received quickly or slowly, and by annualizing the amount you distort the net total expose that anyone in those areas would receive.
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Nice job, I love charts
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Just saw that your chart made it on Al Jazeera:
http://english.aljazeera.net/indepth/spotlight/japan/2011/03/201132464127410510.html
Congrats!
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@pauls (et al):
I don’t know where Monroe was getting his numbers from, but you can get measured radiation levels directly from the source from the reactor status updates posted at http://www.jaif.or.jp/english/
(http://english.kyodonews.jp/news/japan_nuclear_crisis/ is also a good source of news stories)
The measured radiation levels have varied quite a bit over time, as Randall explicitly stated in his chart, and average radiation level for towns around the reactor is probably so vague as to be meaningless. But it’s just one data point in a pretty useful chart.
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Hey, your chart is also on on EDGE.org now:
http://edge.org/documents/tsunami/tsunami11_index.html
More Congrats!
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Thank you, thank you, thank you! Today I was at the public information forum that VCU hosted regarding the Japanese earthquake and events following – it was great forum filled with factual information. I am not a college student, but I have decades of nuclear experience and I knew the hosts of the event, so I knew it would be good. In their slide presentation, they included your visual representation of relative exposures. I had seen it before the meeting, so I was doubly imipressed that they included it.
After the presentations, there were questions. One mech engr student asked about relative exposures between Fukushima and Chernobyl. The answer was in your graphic, of course, but the resolution didn’t work for power point, so it was tough to answer with details in that forum.
You should have seen the look on that guy’s face when I handed him a slip of paper with your webaddress on it and told him that’s where the answer was. He recognized your site, and was amazed that someone twice his age was recommending it to him for technical answers. You made my day; thank you thank you thank you!
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The Guardian is now backing up its arguments with XKCD pictures!
http://www.guardian.co.uk/commentisfree/2011/mar/21/pro-nuclear-japan-fukushima
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@jp
Yes, the EPA limit is from other than natural sources and does not include normal background dose, just incidental dosage from normal radiological operations.
@pauls
When I was in vocational school learning how to do my job, my teacher told me you get 1 REM (roentgen equivalent man) of exposure from an MRI. I did not get that piece of information from the chart, but from school. We use REMs and milliREMs in my job, so I used the allowable exposure for a radiation worker in mSv shown on the chart (50 mSv) and my own knowledge of allowable exposure in mREMs (5000, or 5 REMs) to create an equation and calculated that 1,000 mREMs, or 1 REM, is equal to 10 mSv.
Equation: x/100=y where x=dose in mREMs and y=dose in mSv
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So 3 guys standing in water pulled 2-6 Sv . By the chart they are lightly browned to charred toast.
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“unless its a bananaphone” lol.
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@Kelly
An Austrian group has estimated I-131 and Cs-137 source strengths for March 12 thru 15 based on CTBTO (i.e. test ban treaty organization) data. I posted links to their website last night in the comments, but either man or machine has prevented the comment from being posted.
Links to English reports, if they exist, are at the bottom of web pages.
http://www.zamg.ac.at/aktuell/index.php?seite=1&artikel=ZAMG_2011-03-25GMT15:41
English report on estimated I-131 and Cs-137 source strengths.
Click to access Japan2011-03-22_1500_E.pdf
Google translate does a pretty decent job on the web pages themselves.
Short story is that ZAMG estimates I-131 releases in the first four days of the crisis were 20% of the total I-131 releases from Chernobyl. Cs-137 releases over the same period were 50% of total Cs-137 released in the entire Chernobyl incident.
Now that another ten days have gone by with emissions still occurring, it’s probably safe to say that the Japanese reactors have released more fallout that was released at Chernobyl. The main reason the effect hasn’t been as bad is that the releases have mostly blown out to sea.
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@eddie, @viviwannabe, et. al.
Seems I’ve been muzzled. My last post last night and one made just now have been shuffled off to ‘being moderated’ land. It’s disappointing to see apparent censorship over disagreements about technical detail and style.
I’ll leave off with information that Kelly might want to pass on, since someone asked about this.
— pauls
@Kelly
An Austrian group has estimated I-131 and Cs-137 source strengths for March 12 thru 15 based on CTBTO (i.e. test ban treaty organization) data. I posted links to their website last night in the comments, but either man or machine has prevented the comment from being posted.
Links to English reports, if they exist, are at the bottom of web pages.
http://www.zamg.ac.at/aktuell/index.php?seite=1&artikel=ZAMG_2011-03-25GMT15:41
English report on estimated I-131 and Cs-137 source strengths:
Click to access Japan2011-03-22_1500_E.pdf
Google translate does a pretty decent job on the web pages themselves.
Short story is that ZAMG estimates I-131 releases in the first four days of the crisis were 20% of the total I-131 releases from Chernobyl. Cs-137 releases over the same period were 50% of total Cs-137 released in the entire Chernobyl incident.
Now that another ten days have gone by with emissions still occurring, it’s probably safe to say that the Japanese reactors have released more fallout than released at Chernobyl. The reason the consequences aren’t the same is that the releases have mostly blown out to sea.
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@eddie, @viviwannabe, et. al.
Seems I’ve been muzzled. Last three attempted comments have been shuffled off to ‘being moderated’ land. It’s disappointing to see apparent censorship over scientific/technical disagreements. I certainly didn’t expect that here.
Anyway, before I take my toys and leave, here’s some information that Kelly might want to pass on, since someone asked her about Japan vs. Chernobyl.
– pauls
@Kelly
An Austrian group has estimated I-131 and Cs-137 source strengths from the Japanese reactors for March 12 thru 15 based on CTBTO (i.e. test ban treaty organization) data.
Links to English reports, if they exist, are at the bottom of web pages. Google translate does a pretty decent job on translating page text.
http://www.zamg.ac.at/aktuell/index.php?seite=1&artikel=ZAMG_2011-03-25GMT15:41
English report on estimated I-131 and Cs-137 source strengths:
Click to access Japan2011-03-22_1500_E.pdf
Short story is that ZAMG estimates I-131 releases in the first four days of the crisis were 20% of the total I-131 releases from Chernobyl. Cs-137 releases over the same period were 50% of total Cs-137 released from Chernobyl.
Now that another ten days have gone by with emissions still occurring, it’s probably safe to say that the Japanese reactors have released more fallout than Chernobyl. The reason the consequences aren’t the same is that the releases have mostly blown out to sea.
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