Japan Earthquake: Nuclear Plants at Fukushima Daiichi

AI Thread Summary
The Fukushima Daiichi nuclear plant is facing significant challenges following the earthquake, with reports indicating that reactor pressure has reached dangerous levels, potentially 2.1 times capacity. TEPCO has lost control of pressure at a second unit, raising concerns about safety and management accountability. The reactor is currently off but continues to produce decay heat, necessitating cooling to prevent a meltdown. There are conflicting reports about an explosion, with indications that it may have originated from a buildup of hydrogen around the containment vessel. The situation remains serious, and TEPCO plans to flood the containment vessel with seawater as a cooling measure.
  • #8,001
Borek said:
Please, not a "what this pixel is" again.

Color that you see depends on the light at the place picture was taken, white balance of the camera and color temperature of your monitor (and other things). In some cases original colors are irreproducible on the screen no matter how you try, in some cases they are changed beyond recognition. So while there is some reddish tint in this place, it accurate shade is questionable.

Shapes do look "brickish" but if you desaturate the image (making it black and white) they no longer look like bricks, just like a random rubble. It is combination of shape and color that tricks you into thinking about bricks.

I like the idea of a paint bomb.

As a photographer I can attest to this. Also, both digital cameras and the systems we use to view them have a hard time with the color red.

You cannot analyze the color in a photograph unless you've taken it with very specialized equipment. We can see that it is red, but what shade is impossible to say.
 
Engineering news on Phys.org
  • #8,002
jlduh said:
Concerning this particular picture that you mention:
http://www.netimago.com/image_202874.html

I remarked when i saw it first when it was released by digitalglobe that there were those very bright spots encircled with coloured lines, especially on some roofs but also around the reactors on the ground. AT first i thought that these could be some glowing parts of fuel or corium emitting a very intense light, as in digital photography, this kind of fringing appears around very bright spots in an image, in fact this comes from an overflow of photos in the adjacent pixels when the pixels receiving too much light are saturating (which is called BLOOMING).

There are many different kinds of things which cause fringing. There are optical defects that are present in the lens, different sensor types might cause fringing (e.g Blooming, which is only present in CCD sensors).
jlduh said:
I tried to see on all the other pictures i saw after from the plant if i could do a correspondance between these spots seen on this picture taken just after explosion of N°3 and some specific areas with remaining debris. In fact i didn't succeed in doing this: those spots didn't appear to me to be of special interest based on the later pictures.

So i don't know what to think. For sure these bright spots circled with color are surprising at first sight. On the other hand, we see in the sea area (on the same picture) that there are a lot of speculars coming from what looks to be like aluminum sheets reflecting in the sun. I don't know if there is something special on the water that makes it shining like that, or if it is just from the waves and the sun playing together (i think this second option is the good one). For sure, the picture is a little bit overexposed and the sun reflecting here and there doesn't help.

Now, even if the spots on the roofs for example are not "glowing corium" (which was not evidently) but reflections from shiny parts, we shoud find evidence of some of those parts on other pictures. I had a hard time to confirm this either... So i guess this needs maybe further look and analysis. But again maybe it's just speculars on some small shiny parts, we all know how bright this can be if just at the right angle!

Concerning the white dots in some pictures in areas with radioactivity: this is a different subject than above but to me this is clearly the effect of the radiations (gamma) on the sensor. This is very well shown in the experiment in the video posted. Some of these dots may be in fact dead pixels from a previous exposure (like in the experiment shown) or pixels reacting to some gamma rays i think.

CCDs are considered more proned to this than CMOS but CMOS are also vulnerable to this. There is a complete thesis available on this subject:

http://www.cse.yorku.ca/visor/pdf/MSc_thesis_Henok.pdf

The "fringin" on the highlights in the photo is with 99% certancy an optical effect caused by the Earth's atmosphere coupled with the extreme optics needed to get images like this from Earth orbit. There's no WAY that radiation could cause this. Also if the highlights weren't reflections of sunlight then the light source that produced them has to be as bright or brighter than the sun. And that would be kind-of noticeable on the ground.
 
Last edited by a moderator:
  • #8,003
This. From the live feed. No zooming and no cropping on my part.

unit4_int.jpg


EDIT: also, this
unit4int1.jpg
 
Last edited:
  • #8,004
Maxion said:
There are many different kinds of things which cause fringing. There are optical defects that are present in the lens, different sensor types might cause fringing (e.g Blooming, which is only present in CCD sensors).


The "fringin" on the highlights in the photo is with 99% certancy an optical effect caused by the Earth's atmosphere coupled with the extreme optics needed to get images like this from Earth orbit. There's no WAY that radiation could cause this. Also if the highlights weren't reflections of sunlight then the light source that produced them has to be as bright or brighter than the sun. And that would be kind-of noticeable on the ground.

I agree. I was talking about the withe dots for example in this picture already posted, which are a totally different subject than the fringing in the satellite image, as i mentionned it...

http://www.netimago.com/image_202891.html
 
Last edited by a moderator:
  • #8,005
interesting figures. The 500 mSv however could be misleading. The title of the map is "organ dose of I-131". Assuming they mean the organ thyroid gland, which has a weighting-factor of 0,05, the resulting effective dose would be 25 mSv.

They explicitly stated "thyroid equivalent dose", from the pdf. They have already corrected for thyroid uptake.
 
  • #8,006
~kujala~ said:
Hello jpquantin,
As you have calculated the loss rates of SFP 4 is it possible that the SFP 4 at some point has overflowed?
When they spray water over the SFP is there any mechanism that prevents it from overflowing except "let's stop the pumps"?

AFAIK water flows into the FPC skimmer surge tank. The highest recorded level for SFP4 skimmer level is 6600; without knowing how high can this measure go, one cannot know if water has overflowed.

SPF4 losses are quiet constants, if we trust skimmer level as indicating the pool is full when its level rises. My own calculation are (first date pool is full, second tons of water lost per day until full signal):
13/04 6:57 => 46 - 47
15/04 18:29 => 56 - 57
17/04 21:22 => 66 - 67
27/04 14:44 => 124 - 125
07/05 17:30 => 56 - 57
11/05 19:38 => 53 - 54
21/05 19:56 => 54 - 55

I've rechecked figures between 17/04 and 27/04, and still find a rate exceeding by far the constantly boiling rate (which is about 85 tons per day). It can be many things, including errors in reported sprayed volumes, water not reaching SPF ... or alien heat.
 
  • #8,007
zapperzero said:
This. From the live feed. No zooming and no cropping on my part.

View attachment 35798

EDIT: also, this
View attachment 35805

The images look just as distorted as they did 2 weeks ago. Is there something new and noteworthy there?
 
  • #8,009
Last edited by a moderator:
  • #8,010
Is it possible to locate the seawater pumps of Fukushima Daiichi precisely on satellite views or on the map at http://www.tepco.co.jp/en/nu/fukushima-np/f1/images/f1-sv-20110323-e.pdf ? According to http://www.yomiuri.co.jp/dy/national/T110410003477.htm they are "near water intake outlets". According to http://www.asahi.com/english/TKY201104060126.html they were "not located within a sealed structure" and had been designed at a time prior Hitachi and Toshiba gained the experience that would lead them to locate seawater pumps "within buildings".
 
Last edited by a moderator:
  • #8,011
tsutsuji said:
Is it possible to locate the seawater pumps of Fukushima Daiichi precisely on satellite views or on the map at http://www.tepco.co.jp/en/nu/fukushima-np/f1/images/f1-sv-20110323-e.pdf ? According to http://www.yomiuri.co.jp/dy/national/T110410003477.htm they are "near water intake outlets". According to http://www.asahi.com/english/TKY201104060126.html they were "not located within a sealed structure" and had been designed at a time prior Hitachi and Toshiba gained the experience that would lead them to locate seawater pumps "within buildings".

Ok, on google maps i checked but it is very difficult to see it due to the poor resolution. On the picture below, you see on the right the four water intakes (one for each reactor, N°1 is smaller because the reactor is smaller in fact). Then if you move a little bit on the left, then you will see some spherical grey objects, aligned parallel to the intake, these are the pumps: 2 for N°1, 3 for N°2 to 4 but at N°4, because they were doing maintenance on the core, it seems they were also doing maintenance on the pumps because they seem to be removed on this picture. You can see that they are very vulnerable from tsunami standpoint (they must be close to the sea to some extent of course!) and they are also critical in order to keep the cold source working!

http://www.netimago.com/image_202942.html

I add this other satellite view, you see very well the difference between the N°1 and the others (size of intake and N° of pumps)

http://www.netimago.com/image_202943.html

I add a picture showing how they look like -these are from N°5 reactor and got hit by this big blue structure, but they look similar to the others:

http://www.netimago.com/image_202944.html

Do you see them?

Note 1 : I add this other picture showing the all 6 reactors from the sea, so you see very well the size of the various intakes and the grey pumps in the alignment:

http://www.netimago.com/image_202948.html

Note 2: At DAINI plant, which is newer, they added some buildings close to the sea but to me, these pumps are still outside, close to these buildings (the 3 aligned white/grey circles each time)

http://www.netimago.com/image_202950.html
 
Last edited by a moderator:
  • #8,012
Last edited by a moderator:
  • #8,013
MiceAndMen said:
The images look just as distorted as they did 2 weeks ago. Is there something new and noteworthy there?

Hm? What distorsion?

EDIT: the camera was focused on unit #4 and panning left to right, then back again.
 
Last edited:
  • #8,014
jlduh said:
Do you see them?

Thank you. Thanks to your pictures, I think I could see all of them, except those for unit 4. Have they been wiped out by the tsunami, or have they already been removed for cleanup or repair ?

Their absence is conspicuous on :
http://www.netimago.com/image_202942.html

jlduh said:
and got hit by this big blue structure
Are you sure ? Looking at that picture, it is difficult to say if the blue structure is close or far enough behind.
 
Last edited by a moderator:
  • #8,015
SteveElbows said:
More detailed analysis of accumulated turbine building water from march sampling finally published:

http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_110522_04-e.pdf

Any comments?

Yep. Ruthenium, Strontium, Uranium and Plutonium present. That's used fuel, basically. It needs to have melted down for this stuff to be mobilized, I think.
 
Last edited by a moderator:
  • #8,016
tsutsuji said:
Thank you. Thanks to your pictures, I think I could see all of them, except those for unit 4. Have they been wiped out by the tsunami, or have they already been removed for cleanup or repair ?

Their absence is conspicuous on :
http://www.netimago.com/image_202942.html


Are you sure ? Looking at that picture, it is difficult to say if the blue structure is close or far enough behind.

Well, on this other picture taken March 12, after the tsunami, you see that in the area close to intake N°4, there were some blue covers at the intake, and i think this tend to make e think that they were doing some repair in this area when the tsunami hit.

http://www.netimago.com/image_202962.html

But this is a guess, also based on the fact that N°4 was stopped.

For the blue structure, i don't know if it hit or not the pumps at N°5 but fore sure there has been some damage on this structure.

At first, when the accident happened, i heard in the news that they lost first the cold source, then the electrical power. I don't know if all the pumps were still fully functionnal after the tsunami, in addition to loss of electrical power, in fact...
 
Last edited by a moderator:
  • #8,017
jlduh said:
I agree. I was talking about the withe dots for example in this picture already posted, which are a totally different subject than the fringing in the satellite image, as i mentionned it...

http://www.netimago.com/image_202891.html

Yeah, I kind-of ignored that subject because those white dots are definitely an image artifact that I have never seen before. The color white comes when the bayer-filter registers all three color channels as fully saturated. The only artifact that comes close is hot pixels when shooting with high ISOs and long exposure, but they aren't white, or very rarely are.
 
Last edited by a moderator:
  • #8,018
SteveElbows said:
More detailed analysis of accumulated turbine building water from march sampling finally published:

http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_110522_04-e.pdf

Any comments?

For experts: how can you interpret that water from N°1 is significantly less contaminated (orders of magnitude lower for most isotopes) than N°2 and N°3, and that Ba-140, La-140 (short half life) and Sr 89 and 90 are much lower in this N°1 water (see page 3 of pdf)?

Is La-140 a daughter isotope in the decay process of other elements?
 
Last edited by a moderator:
  • #8,019
Maxion said:
Yeah, I kind-of ignored that subject because those white dots are definitely an image artifact that I have never seen before. The color white comes when the bayer-filter registers all three color channels as fully saturated. The only artifact that comes close is hot pixels when shooting with high ISOs and long exposure, but they aren't white, or very rarely are.

The "funny" pixels are not always white. It looks like impulse noise affecting one or more color components to me. I've seen artifacts like these when the CCD power source had noise or when there was some RF interference. There can be several places where the noise could be introduced: in CCD, in ADC converter or when transfering digital data from imager to the processing system. Sometimes the data transfers are done using YUV data channels, so a single bit off could change the overall luminance or color. It's not at all certain that radiation is causing this.
 
  • #8,020
zapperzero said:
Yep. Ruthenium, Strontium, Uranium and Plutonium present. That's used fuel, basically. It needs to have melted down for this stuff to be mobilized, I think.

The U, Pu and Ru are below detection limits as the are all reported as < X.

While there certainly is Radioactive Sr present in large amounts (3rd table), most of the Sr in table 2 (by mass) will be stable Sr from sea water.

Sea water will also contain trace amounts of U, though that leads me to my 3rd point, the detection limits in table 2 are two high to be useful from the point of view of detecting fuel failure etc.

Crap load of 134/137Cs and 90Sr to deal with for long-term clean up though. Pity the table didn't give volume estimates of the various "pools" so we could easily convert this to total inventories of the isotopic activities.
 
Last edited:
  • #8,021
ModelX said:
The "funny" pixels are not always white. It looks like impulse noise affecting one or more color components to me. I've seen artifacts like these when the CCD power source had noise or when there was some RF interference. There can be several places where the noise could be introduced: in CCD, in ADC converter or when transfering digital data from imager to the processing system. Sometimes the data transfers are done using YUV data channels, so a single bit off could change the overall luminance or color. It's not at all certain that radiation is causing this.

I never said it was ;) I tried to ignore the subject because my knowledge of how an image is formed on a sensor and it's path to becoming a RAW or JPG is quite limited. I do know that it is not caused by the cameras normal operation under normal operating conditions.
 
  • #8,022
jlduh said:
For experts: how can you interpret that water from N°1 is significantly less contaminated (orders of magnitude lower for most isotopes) than N°2 and N°3, and that Ba-140, La-140 (short half life) and Sr 89 and 90 are much lower in this N°1 water (see page 3 of pdf)?

Is La-140 a daughter isotope in the decay process of other elements?

I'd like to hear an expert on this too,

My non-expert thinking is the I and Cs isotopes are more volatile and more readily escape the fuel than Sr so the increased Sr in # 2 and 3 likely means much greater damage to fuel and containment for those units.
 
  • #8,023
jarvik said:
The U, Pu and Ru are below detection limits as the are all reported as < X.

One can question this "<". For U in page 2 they explicitly stated "ND" (not detected?). Moreover for Zr in page 2, the detection limits would not be the same for each sample analyzed ... (I understand Italic numbers as being recalculated from analysis of diluted solutions).

Is it plausible that JAEA may not be able to detect concentration lower than 1.2 mg per liter for Pu?
 
  • #8,024
jlduh said:
Note 2: At DAINI plant, which is newer, they added some buildings close to the sea but to me, these pumps are still outside, close to these buildings (the 3 aligned white/grey circles each time)

http://www.netimago.com/image_202950.html

Some details about Daini are provided in this article :
Unit 3 was undamaged and continued to cold shutdown status, but the other units suffered flooding to pump rooms where equipment transfers heat from the reactor circuit to the sea - the ultimate heat sink.
http://www.world-nuclear-news.org/RS_Insight_to_Fukushima_engineering_challenges_1803112.html

I wonder how enough seawater pumps at Daini unit 3 could remain safe after being flooded by the OP+6m ~ OP+14m wave reported and depicted on dramatic pictures at http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110409e10.pdf, if they are located outdoors. How can we explain the Daini unit 3 miracle ?

The following attachments are from , a video explaining how the Tokai NPP (located further South in Ibaraki prefecture) survived the March 11th tsunami. The video says that the seawater pumps are enclosed in "more than 6 m" high walls, while the tsunami wave was only "more than 5 m" high. Two pumps survived. The third pump didn't survive because its wall was still under construction and not finished.

Tokai NPP's pump protecting wall is also depicted on a diagram at http://www.asahi.com/photonews/gallery/infographics/110330_toukai2.html and on photographs at http://mytown.asahi.com/areanews/ibaraki/TKY201104190562.html (according to that article, the seawater pumps are also providing cooling for the emergency diesel engines ; One diesel engine stopped because the seawater pump for that engine was flooded through a hole in the wall. The reason for the existence of the hole is that the wall was under construction ; If the wall had been 70 cm lower, the Tokai NPP might have had the same destiny as Fukushima Daiichi)
 

Attachments

  • video1min44.jpg
    video1min44.jpg
    21.5 KB · Views: 468
  • video2min09.jpg
    video2min09.jpg
    15.3 KB · Views: 399
Last edited by a moderator:
  • #8,025
jpquantin said:
One can question this "<". For U in page 2 they explicitly stated "ND" (not detected?). Moreover for Zr in page 2, the detection limits would not be the same for each sample analyzed ... (I understand Italic numbers as being recalculated from analysis of diluted solutions).

Is it plausible that JAEA may not be able to detect concentration lower than 1.2 mg per liter for Pu?

Oh I thought it was odd that U was given as ND while most others are reported as <X. The analsyis here is evidently a relatively rough chemical analysis as only the major ions of sea water are given values (Na, Ca, Cl etc) as even expected minor ions like Si are only given <X. From my own experience an analyitical lab will give you an actual value OR give you <X where x is the detection limit in question.

I'm not sure I follow you on the Zr, the < X value is the same for all straight samples and reduced by the dilution factor as appropariate for dilution runs.

The inability to detect Pu I think is another reflection of this being a wet chemical method and not a radiometric method which would be far superior at detecting Pu.

In all honesty the detection limits seem piss poor for the question that will obviously be asked from the data (fuel failure?) but more appropriate for asking what % is sea water and water % is fresh water sourced in each sampling pool.

For a comparison I recently have gotten some chemical elemental (30 elements) analysis data back for some work I'm doing and looking at it the reported detection limits vary by element but for example they have a detection limit of 0.05 mg U /kg soil and 0.5 mg Mo/kg soil for the lab we went with. Seems far better than Tepcos lab sadly.
 
  • #8,026
jlduh said:
Is La-140 a daughter isotope in the decay process of other elements?

Yes. It is daughter of Ba-140, which in turn can be found in the decay chains of both U-238 and U-235, iirc. But I can't find a chart so... let's wait for the experts.
 
  • #8,027
zapperzero said:
Yes. It is daughter of Ba-140, which in turn can be found in the decay chains of both U-238 and U-235, iirc. But I can't find a chart so... let's wait for the experts.

Er.. you mean fission product of U I expect.
 
  • #8,028
  • #8,029
zapperzero said:
This. From the live feed. No zooming and no cropping on my part.

Sigh. Try to locate the *pillars*. Do NOT use the outline of the building (walls, corners and roof) since it is obscured by hanging debris, sagging beams, paint spots and such. Then check the pipes in the tower.
 
  • #8,030
jlduh said:
2 for N°1, 3 for N°2 to 4 but at N°4, because they were doing maintenance on the core, it seems they were also doing maintenance on the pumps because they seem to be removed on this picture.

I think that the missing pumps were swept away by the tsunami. One of them (an isolated pump due west from unit #2) is still lying on its side, not far away from its presumed base. I would guess that the other missing ones were rolled into the sea by the receding wave.
 
  • #8,031
[PLAIN]http://www.yomiuri.co.jp/photo/20110419-495936-1-L.jpg
Diagram from http://www.yomiuri.co.jp/science/news/20110419-OYT1T01008.htm

It shows that in order that the contaminated water moved from unit 2 does not leak into the ground water, it will not be allowed to fill more than the second basement floor of the process main building.
 
Last edited by a moderator:
  • #8,032
Jorge Stolfi said:
Sigh. Try to locate the *pillars*. Do NOT use the outline of the building (walls, corners and roof) since it is obscured by hanging debris, sagging beams, paint spots and such. Then check the pipes in the tower.

I see I have a reputation which is following me , and it's not a good reputation

Anyway. I was interested in the pictures because you can just make out a gantry crane and the huge beam it travels on. Second pic shows a tower that is rarely present in the feed.
 
  • #8,033
jlduh said:
Note 2: At DAINI plant, which is newer, they added some buildings close to the sea but to me, these pumps are still outside, close to these buildings (the 3 aligned white/grey circles each time)

http://www.netimago.com/image_202950.html

[URL]http://www.asahi.com/national/update/0405/images/TKY201104050670.jpg[/URL]
This diagram is taken from http://www.asahi.com/national/update/0405/TKY201104050625.html

The upper part is Fukushima Daiichi.
The lower part is Fukushima Daini.

The horizontal red rectangles are the emergency diesel generators.
The small vertical red pins are named "seawater pump"
The quadrilateral shape around Daini's seawater pump is named "seawater pump building"
扉 is "door".

According to this diagram, at least the pumps sending seawater to provide cooling for the diesel generators are indoors at Daini. Perhaps only these pumps are indoors while the other pumps are outdoors ?
 
Last edited by a moderator:
  • #8,034
jlduh said:
For experts: how can you interpret that water from N°1 is significantly less contaminated (orders of magnitude lower for most isotopes) than N°2 and N°3, and that Ba-140, La-140 (short half life) and Sr 89 and 90 are much lower in this N°1 water (see page 3 of pdf)?

I am a non-expert but still trying to answer this one as I have a theory.
They did not spray sea water to unit #1 SFP.
AFAIK the first spray they did (and all sprays after that) were done using fresh water.
March 31st 13:03~16:04 Water spray by Concrete Pump Truck (Fresh water) ...

The really contaminated water in the unit #1 could be in the basement of the reactor building whereas the water in the basement of the turbine building could have come mainly from tsunami/SFP sprayings. Also perhaps some groundwater has leaked in but not enough to affect the levels of contamination heavily.

Once they measure SFP contamination levels in #1 it could further confirm this kind of theory.
The expected result would be to see low-level contamination in #1 SFP.
 
  • #8,035
http://atmc.jp/plant/rad/

Where in each plant are those outrageous Sieverts per Hour readings coming from? Is it in the control centers? Is there something wrong with the data? Does Sv/hr in Japan mean something different from what I think it means. The readings from Unit Five and Unit Six are frightening considering that they were in cold shutdown at the time of the Tsunami.
 
Last edited by a moderator:
  • #8,036
Joe Neubarth said:
http://atmc.jp/plant/rad/

Where in each plant are those outrageous Sieverts per Hour readings coming from. Is it in the control centers? Is there something wrong with the data? Does Sv/hr in Japan mean something different from what I think it means.

First plot is for unit 1, and if you will read tepco data you will see that there was big radiation jump in drywell, but we don't know if this is correct, sensor can be damaged, if data is correct than this could be corium which get into drywell from RPV
http://www.tepco.co.jp/nu/fukushima-np/f1/images/11052306_level_pr_data_1u-j.pdf
 
Last edited by a moderator:
  • #8,037
The following article http://astand.asahi.com/magazine/judiciary/articles/2011051100015.html?iref=chumoku expresses the view that most diesel generators at Fukushima Daiichi are water-cooled : "The tsunami hit the seawater pumps and water intake became impossible. As a consequence, the 10 water-cooled emergency diesel generators stopped (...) Unit 2, unit 4 and unit 6 have one air-cooled emergency diesel generator each. (...) Those at unit 2 and unit 4 failed too. They are located high above sea level, which raises the possibility that what failed was the metal-clad switchgear which acts as the electric power receiving end at the building"

A photograph showing seawater pumps being removed for inspection at Ikata NPP can be viewed at : http://mytown.asahi.com/areanews/ehime/OSK201105190135.html
 
Last edited by a moderator:
  • #8,038
Maxion said:
The "fringin" on the highlights in the photo is with 99% certancy an optical effect caused by the Earth's atmosphere coupled with the extreme optics needed to get images like this from Earth orbit.

Thanks for your interpretation. So there is 1% left those colored sparkles are optical effects simply from oil? ;-)

-->
http://www.netimago.com/image_202942.html

I have to look for similar fringed spots in satellite photos of the mexican gulf desaster ...

EDIT: Colored sparkles found here, American Samoa Tsunami, no radioactivity needed :
http://www.flickr.com/photos/digitalglobe-imagery/3969593680/sizes/l/in/photostream/
 
Last edited by a moderator:
  • #8,039
elektrownik said:
First plot is for unit 1, and if you will read tepco data you will see that there was big radiation jump in drywell, but we don't know if this is correct, sensor can be damaged, if data is correct than this could be corium which get into drywell from RPV
http://www.tepco.co.jp/nu/fukushima-np/f1/images/11052306_level_pr_data_1u-j.pdf

Ouch. Let's hope only the sensor broke. We'll know soon.

Btw.: Can such values be reached without recriticality?
 
Last edited by a moderator:
  • #8,040
radiation measurement live from Japan
μSv/h

Iitate village, Fukushima pref
39.5 km away from Fukushima Daiichi
http://www.ustream.tv/channel/8000164

Fukushima city, Fukushima pref
67 km away from Fukushima Daiichi
http://www.ustream.tv/channel/8060606

Hokida, Fukushima city, Fukushima pref
http://www.ustream.tv/channel/8073183

Miyagi pref
http://www.ustream.tv/channel/7954538

near Sendai station, Miyagi pref
http://www.ustream.tv/channel/8126354

Mito city, Ibaraki pref
http://www.ustream.tv/channel/7574817

Adachi ward, Tokyo
seismometer(L) & radiation measurement(R)
http://www.ustream.tv/channel/7754813

Shinjuku ward, Tokyo
http://www.ustream.tv/channel/7943728

Tsurumaki, Setagaya ward, Tokyo
http://www.ustream.tv/channel/8278742

Asakusa, Taito ward, Tokyo
http://www.ustream.tv/channel/7658661

Asakusabashi, Taio ward, Tokyo
http://www.ustream.tv/channel/7873981

Katsushika ward, Tokyo
http://www.ustream.tv/channel/7373757

north Tokyo
200km away from Fukushima Daiichi
http://www.ustream.tv/channel/7485012

Kashiwa city, Chiba pref
http://www.ustream.tv/channel/7555976

Chiba city, Chiba pref
http://www.ustream.tv/channel/7960747

Inage ward, Chiba pref
http://www.ustream.tv/channel/7691874

Yachimata city, Chiba pref
http://www.ustream.tv/channel/8211793

Ichinomiya seaside area, Chiba pref
http://www.ustream.tv/channel/7817633

Kuki city, Saitama pref
http://www.ustream.tv/channel/7800484

Yamato city, Kanagawa pref
http://www.ustream.tv/channel/8315787

Tsuru city, Yamanashi pref
http://www.ustream.tv/channel/8244010

Ueda city, Nagano pref
http://www.ustream.tv/channel/7545780

Shijokarasuyama, Kyoto city, Kyoto
http://www.ustream.tv/channel/7752205

Kita ward, Osaka
http://www.ustream.tv/channel/7752284

Kakogawa city, Hyogo pref
http://www.ustream.tv/channel/8207434
 
Last edited by a moderator:
  • #8,041
Broken pipes discovered at Hamaoka's No. 5 nuclear reactor
http://www.asahi.com/english/TKY201105210146.html

[PLAIN]http://www.asahicom.jp/english/images/TKY201105210310.jpg

At least 20 of the approximately 21,000 titanium pipes, which are 0.5 millimeters thick and have a diameter of 3 centimeters, had cracks or holes in them.

The damage appears to have been caused by the end cap of a nearby pipe, which came off and was found on the ground. It possibly became dislodged due to worn welds, but the details are yet to be confirmed, according to a Chubu Electric official
 
Last edited by a moderator:
  • #8,042
AntonL said:
radiation measurement live from Japan
μSv/h

Iitate village, Fukushima pref
39.5 km away from Fukushima Daiichi
http://www.ustream.tv/channel/8000164

Thanks! This one in Iitate is on a 30-second average mode, varying wildly between 0.4 and 0.9 uSv/h

Many seem uncalibrated, though :(. One is dead, no battery :P.
 
  • #8,043
Maxion said:
Yeah, I kind-of ignored that subject because those white dots are definitely an image artifact that I have never seen before. The color white comes when the bayer-filter registers all three color channels as fully saturated. The only artifact that comes close is hot pixels when shooting with high ISOs and long exposure, but they aren't white, or very rarely are.

ModelX said:
The "funny" pixels are not always white. It looks like impulse noise affecting one or more color components to me. I've seen artifacts like these when the CCD power source had noise or when there was some RF interference. There can be several places where the noise could be introduced: in CCD, in ADC converter or when transfering digital data from imager to the processing system. Sometimes the data transfers are done using YUV data channels, so a single bit off could change the overall luminance or color. It's not at all certain that radiation is causing this.

Maybe it's not certain, but it is very probable that the suspicious "bad pixels" are caused by radiation.

Some background to this: Dynamic circuitry, like DRAMs and many processors is very sensitive to radiation from structure micron size about short before the megachips' era.

About 25 years ago, DRAM chips producers began commonly to provide the chips with a thin dense coating directly on the finished die to protect the small charges of the data storage capacitors from getting altered by particles and photons emitted just by the plastic casing of the chips.
This is reflected in the soft error specifications of the DRAM manufacturers.

However, little proven facts are available regarding modern consumer digital cameras and the effects of radiation.

Here an interesting article of a Cambridge University team working on a radiation-hardened camera sensor, explaining some of the radiation effect in the semiconductor: http://iopscience.iop.org/1748-0221/6/03/C03003/pdf/1748-0221_6_03_C03003.pdf

I found another report on evaluating CCD camera sensors for use in highly irradiated accelerator areas, regarding both durability and temporary image distortions.

They used a TRIGA research reactor as radiation source to find out if a CCD camera can survive usage in an accelerator.

They found out that some camera sensors can survive up to 100 Gy, but also that temporary image distortions ("pixels" for those who hate this word ;) ) definitely show up very clearly at 100 mSv/h.

http://img852.imageshack.us/img852/3290/hotspotcamera.jpg

For the detailed report please see here: http://www.isprs.org/proceedings/XXXVI/part5/paper/MARB_645.pdf

So I think that the strange spots you can very clearly see in the high-resolution picture linked here ( http://www.tepco.co.jp/en/news/110311/images/110519_3_4.jpg ) are still quite interesting.

We have to consider that the men walked in areas up to around 2 Sv/h!

Maybe it is just that we just don't get shown the really disturbing images completely speckled with radiation noise that one could expect at 2 Sv?
 
Last edited by a moderator:
  • #8,044
ottomane said:
Ouch. Let's hope only the sensor broke. We'll know soon.

Btw.: Can such values be reached without recriticality?

Not according to TEPCO.

http://www.tepco.co.jp/en/press/corp-com/release/11042713-e.html"

So it's either:

a.) Sensor malfunction
or
b.) A "transient criticality".

What does the supporting evidence suggest?
 
Last edited by a moderator:
  • #8,045
Borek said:
Iodine is too volatile to stay in open place for that long. Besides this is not an iodine color.

In my experience it's not *that* volatile. The temperature where it melts is 113C and sublimation occurs about 113.7C at the triple point, and I doubt that rubble pile is that hot.

I've handled Iodine crystals a fair bit, and they don't evaporate away at normal temperatures. I've melted/sublimated it into purple vapors and seen what surfaces the vapor deposits on look like and how such deposits persist for extended periods.

The resulting deposits from those vapors have often appeared similar in color to what shows in the picture depending on the nature of the surface and how heavy the deposit. The resulting colors I've seen have ranged from light red/brown through dark bluish purple (almost dark enough to look black).

Not saying it has to be Iodine, but I don't think it's all that far fetched that Iodine deposits could discolor things that were exposed to it as a vapor, nor that such deposits could persist at temperatures below 100C.

The real question is whether the Iodine vapor was present in sufficient concentration to form a visible deposit. That I'm not so sure about.
 
  • #8,046
Atomfritz said:
Maybe it's not certain, but it is very probable that the suspicious "bad pixels" are caused by radiation.

Some background to this: Dynamic circuitry, like DRAMs and many processors is very sensitive to radiation from structure micron size about short before the megachips' era.

About 25 years ago, DRAM chips producers began commonly to provide the chips with a thin dense coating directly on the finished die to protect the small charges of the data storage capacitors from getting altered by particles and photons emitted just by the plastic casing of the chips.
This is reflected in the soft error specifications of the DRAM manufacturers.

However, little proven facts are available regarding modern consumer digital cameras and the effects of radiation.

Here an interesting article of a Cambridge University team working on a radiation-hardened camera sensor, explaining some of the radiation effect in the semiconductor: http://iopscience.iop.org/1748-0221/6/03/C03003/pdf/1748-0221_6_03_C03003.pdf

I found another report on evaluating CCD camera sensors for use in highly irradiated accelerator areas, regarding both durability and temporary image distortions.

They used a TRIGA research reactor as radiation source to find out if a CCD camera can survive usage in an accelerator.

They found out that some camera sensors can survive up to 100 Gy, but also that temporary image distortions ("pixels" for those who hate this word ;) ) definitely show up very clearly at 100 mSv/h.

http://img852.imageshack.us/img852/3290/hotspotcamera.jpg

For the detailed report please see here: http://www.isprs.org/proceedings/XXXVI/part5/paper/MARB_645.pdf

So I think that the strange spots you can very clearly see in the high-resolution picture linked here ( http://www.tepco.co.jp/en/news/110311/images/110519_3_4.jpg ) are still quite interesting.

We have to consider that the men walked in areas up to around 2 Sv/h!

Maybe it is just that we just don't get shown the really disturbing images completely speckled with radiation noise that one could expect at 2 Sv?

Afaik, the radiation tests on sensors were done with the sensor directly exposed to the radiation.
That is quite different from the situation when taking a photo. The sensor then is behind a massive lens, which is opaque to all but visible and near IR light. Alpha and beta radiation is excluded therefore, plus it would take quite energetic gamma rays to register on one of these CCD sensors. These would simply be passing through the lens and would not be focused by it.
There may be extreme radiation hot spots on the site, but they will not be found using conventional photographs. A scanning radioactive source meter would be more promising, but these are pretty primitive designs and not especially easy to deploy.
 
Last edited by a moderator:
  • #8,047
ottomane said:
Ouch. Let's hope only the sensor broke. We'll know soon.

Btw.: Can such values be reached without recriticality?
Bodge said:
Not according to TEPCO.

http://www.tepco.co.jp/en/press/corp-com/release/11042713-e.html"

So it's either:

a.) Sensor malfunction
or
b.) A "transient criticality".

What does the supporting evidence suggest?
Is it possible that a fresh blob of corium just dropped into the area near the sensor?
 
Last edited by a moderator:
  • #8,048
zapperzero said:
Thanks! This one in Iitate is on a 30-second average mode, varying wildly between 0.4 and 0.9 uSv/h

Many seem uncalibrated, though :(. One is dead, no battery :P.

Well, now in Iitate i read more than 4,2 (I guess microSievert/h)... Which is much more.
 
  • #8,049
Joe Neubarth said:
http://atmc.jp/plant/rad/

Where in each plant are those outrageous Sieverts per Hour readings coming from? Is it in the control centers? Is there something wrong with the data? Does Sv/hr in Japan mean something different from what I think it means. The readings from Unit Five and Unit Six are frightening considering that they were in cold shutdown at the time of the Tsunami.

The graphs on that site are not good, plenty of errors.

For a start for unit 1 they say that one CAMS reading is from D/W and other from S/C. Its not true, both the sets of data they are showing are for D/W, and they are not showing any S/C readings. TEPCO publish 2 D/W readings and 2 S/C readings, and it is important to note that the unit 1 D/W readings were unavailable for many days due to presumed sensor problems, and indeed the sensor that has recently shows 201 Sv/h has also spiked to high values in the past, so don't know whether to trust it.

As for Units 5 and 6, the site is complete rubbish, it is using wrong data. There are no CAMS readings for reactors 5 and 6, and I have worked out what data it is using by mistake. These numbers are the reported temperatures of the spent fuel pools at units 5 & 6 and should certainly not be in Sv/h. Here is the raw data that I can get to match up, eg look at pool temps at 12:00 on 21st and they match the bogus Sv/h readings on that graph site:

http://www.tepco.co.jp/en/nu/fukushima-np/f1/images/11052306_temp_data_56u-e.pdf

So I would not recommend using that atmc.jp site, use TEPCOs data.

http://www.tepco.co.jp/en/nu/fukushima-np/index-e.html

As for why some of the real numbers are also high, well this equipment is inside containment and is designed to detect fuel melting, so its not surprising that some numbers are high. Yes if many of these higher numbers were from outside containment then this would indeed be cause for great alarm, but they arent, so don't panic.
 
Last edited by a moderator:
  • #8,050
StrangeBeauty said:
Is it possible that a fresh blob of corium just dropped into the area near the sensor?

If I'm understanding it correctly, the TEPCO doc I linked to precludes the possibility of anything in the drywell being *that* radioactive after ~1600 hours.
 

Similar threads

Replies
12
Views
49K
Replies
2K
Views
447K
Replies
5
Views
6K
Replies
2
Views
2K
Replies
763
Views
272K
Replies
38
Views
16K
Replies
4
Views
11K
Back
Top