A Handy Radiation Dose Chart From XKCD 392
An anonymous reader points out Randall Munroe's latest contribution to public health awareness, a "chart of how much ionizing radiation a person can absorb from various sources, compared visually. 1 Sievert will make you sick, many more will kill you, however, even small doses cumulatively increase cancer risk." It's a good way to think about the difference between Chernobyl and Fukushima.
Bananas (Score:5, Informative)
Fascinating, the mention of bananas was smart, since there's something known as Banana Equivalent Dose [wikipedia.org]
additional (Score:5, Informative)
An additional useful chart can be found here, in a slightly more readable and intelligible format:
http://eq.wide.ad.jp/files_en/110315houshasen_mext_en.pdf [wide.ad.jp]
Not as all-inclusive as Randall's work, but still good.
Re:Anti-nuclear clowns (Score:3, Informative)
Uh, not rude? I'm pretty sure calling your opponent a fuckwit [slashdot.org] qualifies as rude. To say nothing of the rest of the comment.
Being rude doesn't matter from a standpoint of factual correctness, but a person can have the facts of their side and still come off looking like a raving lunatic when they write an entire paragraph where every third word is "cock".
Units (Score:5, Informative)
There are so many radiation units out there and people keep using them without regard to what they really mean. It's nice that you've got your Sieverts covered. Now you'll have to learn about Grays, Curies, Becquerels, Rads, Rems, and Roentgens. Here's a handy conversion chart. [stevequayle.com]
No (Score:2, Informative)
It's a good way to think about the difference between Chernobyl and Fukushima.
No. It is not a good way to do that. It would have been if it had included measures like "Ten minutes next to the reactor core of Fukushima after partial meltdown" or "Dose from spending an hour on the grounds at the Fukushima plant in 2036". I'm not saying Fukushima is anywhere near as bad as Chernobyl, but if you want to compare them this chart is not what you need.
Cute, but not accurate (Score:4, Informative)
The Sievert is a measure of ACCUMULATED dose. Time is a factor. Therefore being exposed to 1 Sievert for a second (the real unit behind the sievert is the J/s, which is equivalent to Watts) is the same as being exposed to 1 milisievert for 1000 seconds, or 1 microsievert for 10^6 seconds.
This is also why many measurements are done on a "per hour" basis. 400 milisieverts per hour (near the pool between reactors 3-4) is not harmful to you if you are going to be there for 5 minutes. If you stay there for 2.5 hours, however, you could experience signs of acute radiation sickness.
I find it laughable, however, how the press a) fails to understand this and b) has obvious trouble converting between micro and mili.
Finally one must bear in mind that radionuclides will decay over time (Iodine-131 being the main culprit here, has a half life of 8 days). So in 5 half lives (40 days), most of it will be gone. And also that the chronic health risk of radiation is usually overestimated, especially for such small doses as currently seen in Japan. It's statistical roulette, just like smoking. It just takes one cigarette to unleash the chain of events that will eventually lead to cancer. However the odds of it being the cigarette you are currently smoking are quite small. But if you smoke all your life, you're likely to buy the winning ticket eventually. The same with radiation. There are still living survivors of Hiroshima and Nagasaki, and these people were exposed to far more (and more harmful) radiation - gamma rays vs. beta particles. And yet not that many of them have "grown a third arm". Yes, there have been cancer deaths, but considering the population exposed, it wasn't all that much.
Re:Cute, but not accurate (Score:4, Informative)
(the real unit behind the sievert is the J/s, which is equivalent to Watts) is the same as being exposed to 1 milisievert for 1000 seconds
True mathematically, but not medically [wikipedia.org]
Re:additional (Score:5, Informative)
Re:No (Score:5, Informative)
12mSv/h is slightly more than one red square, no where near an orange one. This makes the highest level of radiation detected, in the cloud of vented gas from inside the containment vessel about 30,000 times less than those at chyernobyl, and only for a very very brief period involving very short half life elements.
The radiation level has since fallen back way down, especially since managing to resubmurge the spent fuel. The reaction has also slowed to about 1/2000th of it's original rates in the reactors, making a melt down extremely unlikely at this point.
Re:No (Score:4, Informative)
That was a peak reading. It must have lasted in the order of a second. And then decreased exponentially. Chernobyl, on the other hand sustained its rate for hours, days, years...
There is a good graph of the readings on http://en.wikipedia.org/wiki/Fukushima_I_nuclear_accidents [wikipedia.org]
Re:Units (Score:5, Informative)
Any idea why there are so many different units of measure for radiation?
Some are historical and SI unit conversions (Rem/RAD and Gray/Sievert); others deal with how does effects what absorbs it. The Roentgen is a measure of gamma energy, the RAD is the measure of energy transferred and is an acronym for Radiation absorbed Dose, which them must be adjusted for a quality factor do to the difference in energy transfer, which generally is referred to as REM - Roentgen Equivalent Man which corrupts for different quality factors so that 1 REM is the same no matter the source of the dose. For practical purposes, Roentgen RAD and REM are equivalent since gamma is generally the radiation of concern.
It's not that different than the measurements - foot meter; slug kilo; punned newton, with the added medical impact measurement.
Re:Cute, but not accurate (Score:5, Informative)
This is actually completely wrong. The Sievert is based on the Gray, which is defined in terms of J/kg. For a fixed mass, it's J, energy. It makes no sense to say "exposed to 1 Sievert for 1 second". You would have to say "exposed to 1 Sievert per second for 1 second".
Re:Why 50km from Fukushima reactor? (Score:3, Informative)
Re:additional (Score:3, Informative)
Re:Anti-nuclear clowns (Score:5, Informative)
Or read this article about how the US coverage from nearly all outlets (not just Fox) is sensationalist, late, and often just wrong?
http://feedproxy.google.com/~r/Talking-Points-Memo/~3/JNlPwKP6WAs/taking_stock_3.php [google.com]
Example: "This has not been just Fox News, but also CNN, MSNBC, ABC, and even the New York Times to differing degrees. They get the reactors mixed up or report information that is simply wrong (e.g., writing that the TEPCO workers had fully abandoned the effort to control the plant because of radiation levels when TEPCO had only withdrawn some non-essential personnel). They are perpetually late, continuing to report things the Japanese media had shown to be wrong or different the day before. They are woefully selective, bringing out just the sensational elements ("toxic clouds" over Tokyowhen in fact radiation in Tokyo now is actually less than that in LA on some days). They are misleading (implying for instance that the dumping of water from the air was some last ditch effort to cool the core, when it was just an effort to replenish the water in the spent rod poolswhich are now full in reactor 3 and back to normal temperature)."
Re:Research (Score:5, Informative)
Apparently xkcd did do more research. Read this article about how the US coverage from nearly all outlets (not just Fox) is sensationalist, late, and often just wrong.
http://feedproxy.google.com/~r/Talking-Points-Memo/~3/JNlPwKP6WAs/taking_stock_3.php [google.com]
Re:Research (Score:5, Informative)
Randal does research for some of his comics.
IPv4 map. [xkcd.com]
Map of the Online Communities [xkcd.com]
2010 Update of the Map [xkcd.com]
Gravity Wells of the Solar System [xkcd.com]
The observable universe from top to bottom (on a log scale) [xkcd.com]
It probably doesn't hurt that he used to work for NASA and is a programmer.
Re:It is and it isn't (Score:5, Informative)
Read your own friggin' articles and stop spreading FUD.
"Yukio Edano, Japan's chief Cabinet secretary, confirmed at a news conference Saturday that milk produced by a farm in Fukushima Prefecture near a crippled power plant and spinach from the neighboring Ibaraki Prefecture were found to be tainted with radiation levels SLIGHTLY [emphasis mine] above that set by the government.
However, Edano said, the contaminated food posed no immediate threat to human health. The public should remain calm, he urged.
Referring to the milk, he said, "drinking it for a year would only expose consumers to the radiation equivalent of one medical CT scan.""
Re:It is and it isn't (Score:3, Informative)
Most of the casualties from Chernobyl (4000 to 8000 fatalities and counting) were from Thyroid cancer.
Check your facts! 4000 cases of thyroid cancer and only 9 fatalities, because it is 99% curable (I think I read somewhere else 15 deaths).