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Japan earthquake - contamination & consequences outside Fukushima NPP

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clancy688
#271
Sep3-11, 10:58 AM
P: 546
Interesting phrasing. So they measured "hotspots" while taking care of staying away from the "hotspots".
NUCENG
#272
Sep3-11, 03:08 PM
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Quote Quote by clancy688 View Post
Interesting phrasing. So they measured "hotspots" while taking care of staying away from the "hotspots".
Sounds suspiscious, doesn't it? It depends on what they are trying to measure.

If they are trying to characterize the general contamination levels they would have a good reason not to measure where it is being concentrated by other phenomena. That would be conservative, but it would skew their results.

If they are trying to characterize maximum dose consequences they should also be measuring these concentrations. This would also be the method to determine if an area can be released for residents to return.
clancy688
#273
Sep3-11, 03:22 PM
P: 546
Quote Quote by NUCENG View Post
If they are trying to characterize the general contamination levels they would have a good reason not to measure where it is being concentrated by other phenomena. That would be conservative, but it would skew their results.
Well, it makes a certain sense. When you measure the dose rate at normal locations (the yard for example) where people stay most the time, you can probably decide whether or not the inhabitants should evacuate. As long as you make sure that they (the inhabitants) stay away from the real hotspots (for example the gutter outflow), it should be possible to make such a decision.
But in that case you can't name the locations you measured "hotspots"...

I just recently watched a little german tv report about inhabitants of Fukushima prefecture. There they showed a farmer who measured 90 uSv/h on his, I quote, "front yard". They showed how he did it. He left the door, turned left, went to the corner of his house and put the counter down on the bottom. Maybe one inch besides the gutter's outflow...
Borek
#274
Sep3-11, 03:54 PM
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Quote Quote by clancy688 View Post
But in that case you can't name the locations you measured "hotspots"...
Depends on what "spot resolution" you are looking for. On the 1m2 scale not checking places were the accumulation is to be expected would be an error, on the 100m2 it can skew the results.
zapperzero
#275
Sep3-11, 04:38 PM
P: 1,042
I'm not sure it's a good idea to not go hotspot-hunting. After all, the overall contamination levels outside the zone (excepting places like Namie and Fukushima City) are not so bad. The real, immediate danger, I think, lies in the small hotspots that such a survey is designed to miss.
Borek
#276
Sep3-11, 05:02 PM
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It is all a matter of resources and speed. Obviously the choice is between quick low resolution scan of large area, or slow high resolution scan. Quick scan doesn't block the high resolution scan, but - and that's an important thing IMHO - gives results for large area much faster. I would prefer a fast scan first.
swl
#277
Sep3-11, 11:58 PM
P: 108
Quote Quote by alpi View Post
A typical example of "research" carried out by anti-nuclear activists.

I checked the local park where my children play to ensure that the area was safe. Only 15 meters away from the swing-set and slide, there is a spot where my GM counter reads 0.70μSv/h to 1.0μSv/h. The 'hot' area is not a gutter, but rather above ground in a grassy area with shrubs nearby. The park I'm talking about (Soka Koen) is located 5.3km north of Tokyo, so I have no doubt that it is easy to find contamination in Tokyo too.

I'm not an activist. My only reason for surveying the park is to keep my children away from the areas I find with elevated contamination.
zapperzero
#278
Sep4-11, 02:12 AM
P: 1,042
Quote Quote by Borek View Post
It is all a matter of resources and speed. Obviously the choice is between quick low resolution scan of large area, or slow high resolution scan. Quick scan doesn't block the high resolution scan, but - and that's an important thing IMHO - gives results for large area much faster. I would prefer a fast scan first.
I would prefer to see resources allocated for a fast, hi-res scan. But yea.
NUCENG
#279
Sep4-11, 04:48 AM
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Quote Quote by swl View Post
I checked the local park where my children play to ensure that the area was safe. Only 15 meters away from the swing-set and slide, there is a spot where my GM counter reads 0.70μSv/h to 1.0μSv/h. The 'hot' area is not a gutter, but rather above ground in a grassy area with shrubs nearby. The park I'm talking about (Soka Koen) is located 5.3km north of Tokyo, so I have no doubt that it is easy to find contamination in Tokyo too.

I'm not an activist. My only reason for surveying the park is to keep my children away from the areas I find with elevated contamination.
Your objective is to find the maximum contamination so you can keep your family safe. You can survey where your children actually go and play. That makes your survey efficient and effective.

The Japanese government and TEPCO do not have targets that are so clear so their surveys are trying to find out where the contamination went. When it comes to free release or cleanup their surveys should be more detailed.

What you found should be shouted from the rooftops as an example that every citizen in the exposed areas should understand. Large area surveys do not prove it is risk free for an individual.

That does not mean they are deliberately trying to miss the hotspots as zapperzero accuses, It is a valid criticism that they have not explained this to the public. And unfortunately that isn't the first time.
zapperzero
#280
Sep5-11, 01:58 PM
P: 1,042
TEPCO says it was 571 billion yen in the red in Q2.
http://www.yomiuri.co.jp/dy/business/T110810005340.htm
Caniche
#281
Sep5-11, 03:47 PM
P: 106
Quote Quote by zapperzero View Post
TEPCO says it was 571 billion yen in the red in Q2.
http://www.yomiuri.co.jp/dy/business/T110810005340.htm
So who is paying the bill? As if
nikkkom
#282
Sep5-11, 07:01 PM
P: 595
Quote Quote by swl View Post
The 'hot' area is not a gutter, but rather above ground in a grassy area with shrubs nearby.
Bioaccumulation perhaps. These plants concentrated Cs as plants would usually concentrate K.
Dmytry
#283
Sep5-11, 09:14 PM
P: 505
Quote Quote by NUCENG View Post
Your objective is to find the maximum contamination so you can keep your family safe. You can survey where your children actually go and play. That makes your survey efficient and effective.

The Japanese government and TEPCO do not have targets that are so clear so their surveys are trying to find out where the contamination went. When it comes to free release or cleanup their surveys should be more detailed.

What you found should be shouted from the rooftops as an example that every citizen in the exposed areas should understand. Large area surveys do not prove it is risk free for an individual.
Hundred percent agreed.
That does not mean they are deliberately trying to miss the hotspots as zapperzero accuses, It is a valid criticism that they have not explained this to the public. And unfortunately that isn't the first time.
One thing that really irked me about this disaster, in the beginning when it was the most important, is the lack of good information on this aspect of the contamination - they would report the contamination figures for cities with two, three, even four figures of accuracy, creating entirely false sense of accuracy, and to some extent playing on people's misunderstanding of difference between radioactivity (as in radioactive dirt) and radiation (as in something that falls off smoothly with distance). They treated the radiation as if it was UV index.

This also goes for this fraud of radiation hormesis and the threshold model, which tries to set a safe threshold or claim a benefit from the low average dose. In principle there could be no safe threshold on the average dose, even if there was a threshold on the safe max dose rate for any tissue, because the doses are not uniform in space and time and may exceed the safe threshold even if the average is below threshold. Thus rendering the threshold model of little use when it comes to declaring contaminated areas safe. Japanese government seem to be rejecting LNT and declaring safe thresholds, while at same time using the averaged doses as if they were to use linear model. That is just bad math.
tsutsuji
#284
Sep7-11, 03:52 AM
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http://www.yomiuri.co.jp/national/ne...OYT1T00524.htm & http://www.jiji.com/jc/c?g=soc_30&k=2011090700630 Pr Kunihiko Takeda of Chubu university was asked by the mayor of Ichinoseki, Iwate, to retract his comment aired on television on 4 September asking viewers to throw away Tohoku-grown food, and saying that agriculture should be suspended for one year.
zapperzero
#285
Sep7-11, 04:36 AM
P: 1,042
Quote Quote by tsutsuji View Post
http://www.yomiuri.co.jp/national/ne...OYT1T00524.htm & http://www.jiji.com/jc/c?g=soc_30&k=2011090700630 Pr Kunihiko Takeda of Chubu university was asked by the mayor of Ichinoseki, Iwate, to retract his comment aired on television on 4 September asking viewers to throw away Tohoku-grown food, and saying that agriculture should be suspended for one year.
Go Streisand effect go.
tsutsuji
#286
Sep8-11, 06:15 AM
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http://mdn.mainichi.jp/mdnnews/news/...dm107000c.html "Above-the-limit cesium found in Iwate beef"

http://mdn.mainichi.jp/mdnnews/news/...dm109000c.html A 15,000 terabecquerel sea release estimate calculated by researchers doesn't match Tepco's estimate for the unit 2 inlet leak last April. "The big gap indicates radioactive substances could have leaked through other channels"
zapperzero
#287
Sep8-11, 06:43 AM
P: 1,042
Quote Quote by tsutsuji View Post
"The big gap indicates radioactive substances could have leaked through other channels"
Some of it is simply airborne contamination that fell to the water surface, no?
tsutsuji
#288
Sep8-11, 07:46 AM
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Quote Quote by zapperzero View Post
Some of it is simply airborne contamination that fell to the water surface, no?
Yes, the NHK seems to view it that way too :

The researchers say the estimated amount of radioactivity includes a large amount that was first released into the air but entered the sea after coming down in the rain.
http://www3.nhk.or.jp/daily/english/08_25.html


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