Japan Earthquake: nuclear plants


by gmax137
Tags: earthquake, japan, nuclear
Borek
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#8011
May23-11, 03:10 AM
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Quote Quote by Atomfritz View Post
Yes, this really disturbs me.
And a closer looking also makes me doubt that this is just dye.
See this zoomed-in image.
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.
jlduh
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#8012
May23-11, 03:23 AM
P: 468
Quote Quote by westfield View Post
Tepco press releases often seem a bit like their plant releases, they do nothing to clear the air.

In this case, are they simply surveying the place, or perhaps looking for a failure point or are they looking to see what equipment can be made serviceable?

If they are looking for a failure point then SGTS ducting outside of primary containment but inside the building would be a good candidate (it's my "favourite" for how hydrogen made it throughout the RB's). The SGTS's projected failure during reactor overpressure "incidents" is what prompted the Direct Torus Vent System retrofit.

However, there are the SGTS ducts, HVAC ducts and others, who knows what the ducting system is in the pictures, who knows why tepco surveyed it and who knows why they showed it to us.


There are lots of docs on the net going into GE Mark 1 BWR "issues" in depth but this one does two of the more likely failures in brief -
Page 4 of this document has a brief section on the Brunswick plant stress test that revealed the BWR Mk1 containment dome lifting off it's seals at 70psi and also the SGTS issue as mentioned above.
Humm, i extract the part that is interesting in this last pdf (TCups may like it !):

According to Lochbaum, workers at Brunswick-2,
which also has the Mark I containment — a design by
General Electric used at units 1, 2 and 3 at Fukushima
I — performed “a structural integrity test on the reactor”
in the 1970s, in order “to satisfy a requirement in the
American Society of Mechanical Engineers (ASME) code
for prototype containment designs.”
Progress says the test is required of all containments
before reactors enter service.
He said workers pumped air into the containment
vessel to raise the pressure inside beyond the designed
maximum of 62 pounds per square inch to 71 psi, but
that the pressure stayed constant at 70 psi. “A hissing
sound attracted workers to the top of the containment
structure,” said Lochbaum. Workers discovered that the
air pushed up the metal containment head, which is
bolted to the containment wall “with a rubber O-ring
between the surfaces,” and seeped out into the refueling
cavity above the primary containment, he said.
“It is possible that the containment pressures [at
Fukushima I units] rose high enough to replicate the
Brunswick experience,” he said.
But while containment leakage in the Brunswick test prevented
the pressure inside from rising above 70 psi, Japan’s
NISA reported that pressure in the containment of unit 1
at Fukushima I had exceeded 120 psi a day after the reactor
had lost cooling. Tepco reported that the containment vessel
pressure at unit 2 had reached above 102 psi.
The interesting stuff if not only the pressure value at which it leaked (which is significantly lower than what some containments at Daichi apparently experienced) but the confirmation (as this has already been discussed) with a real world testing operation that this part of the containment (the seal of the containment cover) is clearly a weak point, making it very probable that some H2 escaped to the refueling well by this path...


There are other elements on the unresolved question of venting at Daichi (and I'm not sure it will make it clearer?):

Ventilation system
As steam accumulated and pressure rose in the containment
vessels, Tepco released some steam outside the reactor
buildings at all three units. Helwig said it is possible that
some steam mixed with hydrogen had escaped into the reactor
building during the venting.
The original Mark I design came with a so-called standby
gas treatment system, or SGTS, to vent steam under emergency
situations. Such a system first scrubs most radioactive
particles out of the steam through filters and then releases it
through the ventilation stack to the atmosphere. Fukushima
I units 1, 2 and 3 are still equipped with the SGTS system,
said a Tepco official, who requested anonymity because he is
not authorized to speak to the press.
The SGTS uses ductwork, which is susceptible to leaking
because it is not air tight and is not designed to withstand
significant pressures, to channel steam, said Helwig.
NRC in the 1980s requested that all US plants with Mark
I containments install hardened vents, replacing ductwork
with hard pipes, according to a March 19 report on the Mark
I by GE Hitachi, the company that combined the nuclear
operations of GE and Hitachi.
Borchardt told NRC commissioners that all US Mark I
reactors now have hardened vents, which he said would not
allow hydrogen to leak during venting.
Alexander Marion, vice president of nuclear operations
for NEI, said in an interview March 22 that US industry
experts assume that Fukushima I reactors do not have hardened
vents, “because somehow they were releasing hydrogen
into the secondary containment, but we just don’t know.”
The Tepco official, who answered questions through
emails, however, said the ductwork SGTS was not used at
Fukushima I for venting, “because the pressure of the containment
vessel was high.” Instead, he said, the company
used an alternative vent called the direct release line, which
can withstand high pressure, to blow off steam and cut
pressure inside the containments. “The direct vent line we
used this time is hardened pipe designed for severe accident
case,” he said.
Maxion
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#8013
May23-11, 03:24 AM
P: 36
Quote Quote by Borek View Post
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.
Maxion
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#8014
May23-11, 03:28 AM
P: 36
Quote Quote by jlduh View Post
Concerning this particular picture that you mention:


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).
Quote Quote by jlduh View Post
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 earths 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.
zapperzero
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#8015
May23-11, 03:37 AM
P: 1,030
This. From the live feed. No zooming and no cropping on my part.

Click image for larger version

Name:	unit4_int.jpg
Views:	203
Size:	23.6 KB
ID:	35798

EDIT: also, this
Click image for larger version

Name:	unit4int1.jpg
Views:	170
Size:	27.2 KB
ID:	35805
jlduh
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#8016
May23-11, 04:05 AM
P: 468
Quote Quote by Maxion View Post
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 earths 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...

intric8
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#8017
May23-11, 04:17 AM
P: 24
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.
jpquantin
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#8018
May23-11, 04:27 AM
P: 33
Quote Quote by ~kujala~ View Post
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.
MiceAndMen
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#8019
May23-11, 05:59 AM
P: 276
Quote Quote by zapperzero View Post
This. From the live feed. No zooming and no cropping on my part.

Attachment 35798

EDIT: also, this
Attachment 35805
The images look just as distorted as they did 2 weeks ago. Is there something new and noteworthy there?
SteveElbows
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#8020
May23-11, 06:35 AM
P: 630
More detailed analysis of accumulated turbine building water from march sampling finally published:

http://www.tepco.co.jp/en/nu/fukushi...10522_04-e.pdf

Any comments?
clancy688
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#8021
May23-11, 07:11 AM
P: 546
Quote Quote by SteveElbows View Post
More detailed analysis of accumulated turbine building water from march sampling finally published:

http://www.tepco.co.jp/en/nu/fukushi...10522_04-e.pdf

Any comments?
10^5 and 10^6 Bq Beta-Radiation per ml... how many tons do they have there? Thousands?
tsutsuji
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#8022
May23-11, 07:23 AM
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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/fukushi...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".
jlduh
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#8023
May23-11, 07:54 AM
P: 468
Quote Quote by tsutsuji View Post
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/fukushi...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!



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)



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:



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:



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)

tsutsuji
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#8024
May23-11, 07:59 AM
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Quote Quote by SteveElbows View Post
More detailed analysis of accumulated turbine building water from march sampling finally published:

http://www.tepco.co.jp/en/nu/fukushi...10522_04-e.pdf

Any comments?
JAEA and JNFL don't agree much with each other.
zapperzero
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#8025
May23-11, 08:08 AM
P: 1,030
Quote Quote by MiceAndMen View Post
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.
tsutsuji
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#8026
May23-11, 08:12 AM
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Quote Quote by jlduh View Post

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 :


Quote Quote by jlduh View Post
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.
zapperzero
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#8027
May23-11, 08:16 AM
P: 1,030
Quote Quote by SteveElbows View Post
More detailed analysis of accumulated turbine building water from march sampling finally published:

http://www.tepco.co.jp/en/nu/fukushi...10522_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.
jlduh
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#8028
May23-11, 08:35 AM
P: 468
Quote Quote by tsutsuji View Post
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 :



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.



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...


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