Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[PietKuip]

I noticed yesterday there was this spike in the sub-drain radiation of the unit 4 on the 20th of April.

Now when examining more closely the sub-drain data the same kind of spike can be seen in the unit 1, 3 and 6.

In this picture I put the data from 1, 3, 4 and 6 on top of each other so that this spike can be more clearly seen:
http://varasto.kerrostalo.huone.net/sub_drain_spike.png

Source:
http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110430e12.pdf

The scariest thing is I-131 steadily increasing under reactor 3.

This looks like criticality to me.

 

[Jorge Stolfi]

Another copy of the photo of the "shadow" with a slightly better resolution.
http://www.abc.net.au/reslib/201103/r733167_5929130.jpg
Found it here: http://www.abc.net.au/news/photos/2011/03/12/3162376.htm
I have no idea what it is, but to me it looks like some sort of rack or grid with kind of a tube on top...

Thanks! Yes, it does seem to be an open gray metal framework supporting a white cylinder with hemispherical caps, i.e. a tank of some sort. Presumably it had a green cover at the time of the "Green Box" photo. Either that cover was a tarpaulin that got removed once installation was finished, or it was a lightweight skin that fell off during the earthquake+tsunami.

The placement of the tank, and the need for a supporting structure, suggests that the tank had something to do with the equipment on the 4th floor.

The SFP lies near that corner, spanning storeys 3 and 4. In both storeys, there is a space perhaps 4-6 m wide between the SFP walls and the south and east outer walls.

According to the blueprints, the outer wall of storey 4 is a bit thicker than that of the service space, and that of storey 3 is thicker still; but the main load still seems to be caried by pillars. (From storey 2 down to the basement the walls are thick enough for the outer pillars to merge completely into them).

 

[StrangeBeauty]

The scariest thing is I-131 steadily increasing under reactor 3.

This looks like criticality to me.

Another possibility is that there is water interchange between the subdrains of #1, 2 and 3. #3 has had I-131 levels below that of #1 and #2 and the graph shows it catching up to those other levels over the last several measurements. If there is no interchange, that would not bode well imo. Additional, refining question is: shouldn't we be seeing the I-131 levels dropping at the 8[STRIKE]hr[/STRIKE] day half life rate rather than remaining constant/increasing? Doesn't this amount of data over time indicate the I-131 is being replenished by some process?

[Edit: thanks PietKuip for correcting me on the I-131 half life time! My point is still valid as you note esp. with regards to caesium amts (see post https://www.physicsforums.com/showpost.php?p=3277990&postcount=5521)]

 

[MadderDoc]

Also the stair is still to see. On the next Fotos, a few days later, the stair is away?? How does is work?

I'm afraid there's not much mystery about the staircase either, sorry. The staircase appears to have been a feature of unit 4 for as long as most people would be able to remember. The staircase leads from the ground to a platform from which service can be made on some ventilator/cooling equipment installed on the roof between unit 4 and its turbine building.

Based on the poor quality imagery of the first helicopter video made after the tsunami, on March the 11th, I'd initially made the assumption that the upper part of the staircase had suffered damage at that stage. However, prodded first by Jorge, then by a photo I found, which appears to have been taken between 8 and 9 am on March the 12th, I no longer think that there can have been any major damage to the upper staircase, until the explosion in building 3, which -- quite unmysteriously -- no part of the staircase seems to have survived.

What gave me the impression from the photo from March 11th that something is missing of the upper part, now I hypothesise, may be just some light debris lying there blurring the view to it.

And the fact that the upper part of the staircase has turned clearly visible on the photo from March 12th, could be just because an employee of Tepco during the evening of the 11th or the morning of the 12th had wanted access to assess damage at the greenbox and had been clearing his way for debris up the stairs. An employee of Tepco _should_ have wanted to do so.

 

[PietKuip]

Another possibility is that there is water interchange between the subdrains of #1, 2 and 3. #3 has had I-131 levels below that of #1 and #2 and the graph shows it catching up to those other levels over the last several measurements. If there is no interchange, that would not bode well imo. Additional, refining question is: shouldn't we be seeing the I-131 levels dropping at the 8hr half life rate rather than remaining constant/increasing? Doesn't this amount of data over time indicate the I-131 is being replenished by some process?

8-day halflife for iodine-131.

The striking thing is that I-131 has been going up for the last week at unit 3, without cesium increasing at the same rate. Indeed, some of those days, the cesium activity decreased.

Soil chemistry is complicated. But the most obvious process replenishing I-131 would be uranium fission.

 

[roliqq]

On WeatherOnline there is a map of radiation readings around Fukushima: http://www.woweather.com/weather/news/fukushima?LANG=us&VAR=radiationoveraccu

which looks scary especially if you take the accumulated data. Can anybody comment/interpret the readings?
There seems to be another hotspot further down south around the Tokai NPP, which is supposed to be shut down since the quake.

 

[fluutekies]

When calculating the leakage rate of the SFP#4 I get these formulas for the leakage rate r:

1. Refill at constant rate:

r₁ = V/t*ln(C(t)/C(0))

2. Refill only once:

r₂ = V/t*(C/C(0) - 1)

The truth is somewhere in between because TEPCO probably does a refill once or twice a day. But this does not really matter: r₁ / r₂ = 1.29.

What is more important: there is the volume V of the SFP in the formula. Now, TEPCO said that the gate between the SFP and the RPV has been destroyed. This would increase the effective volume we have to put into these formula.

With V = 1200 m³ we get a leakage rate of ~40m³/day. Adding ~70m³/day evaporation rate we get 110m³/day total loss rate which is consistent with the refill rate published by TEPCO.

But if we have to increase the volume V (I estimate a factor 3) we get much higher rates (120m³/day leakage rate + ~70m³/day evaporation rate = 190 m³/day total loss rate) which are no longer consistent with refill rate published by TEPCO.

It's indeed difficult to decide which model to apply with such a small amount of hard data. I tend to trust more on the refill rates published than the lucky chance which destroued the gate.

What really surprises me is the fact, that the amount of Cs-137 in SFP#4 is/was so low: 100 mg or less.

Compared to 170 kg U/assembly with 4% "burned" U-235 and a fission yield of 6% Cs-137, the amount of Cs-137 after shut-down is about 400 g Cs-137/assembly: 1/4E+3!

Either the Zr-cladding is only superficially damaged, or the sintered fuel pellets effectively retain the Cs and can't be reached and leached by the surrounding water. (Cs really "loves" water).

Any ideas from the experts?

 

[Rive]

The scariest thing is I-131 steadily increasing under reactor 3.

This looks like criticality to me.

Please, can somebody calculate the energy output of a reaction which ends with x Bq iodine?

 

[PietKuip]

Please, can somebody calculate the energy output of a reaction which ends with x Bq iodine?

The way to gauge the energy output would be to measure a neutron flux somewhere near the reactor.

That is data that Tepco does not wish to publish.

 

[Rive]

The way to gauge the energy output would be to measure a neutron flux somewhere near the reactor.

That is data that Tepco does not wish to publish.

You don't need the neutron flux - that determines only the timeframe of the energy release (but a long timeframe is a bit problematic due the half-life of the iodine ).

Just the amount of iodine (which determines the sum activity) means an energy release during the fission.

 

[Cainnech]

Article 2011/05/01 from The Asahi Shimbun regarding the image of fuel rods in SFP4.

TEPCO releases image inside spent fuel pool at No. 4 reactor
2011/05/01
Tokyo Electric Power Co. released on April 29 an image of fuel assemblies in the storage pool of spent fuel rods in the No. 4 reactor at the Fukushima No. 1 nuclear power plant.
"Although the image shows some rubble sitting on part of a steel rack (of fuel assemblies), no serious damage was identified," TEPCO said.
This is the first time an image of fuel assemblies inside the pool was released to the public after the crisis unfolded at the plant as a result of the Great East Japan Earthquake last month.
The image was taken April 28 with a camera on the tip of the long arm of a concrete pump used to spray water into the pool.
The image showed the status of the storage pool about six meters below the surface of the water.
Fuel assemblies are seen placed in each square of the steel rack in the pool. The image showed glittering new fuel assemblies and darker spent fuel rods. Seven control rods were shown on the right side.
Workers also collected 150 cc of water from the pool April 28 for analysis. Results showed the level of cesium-137 was 55 becquerels per 1 cc of water and that of iodine-131 was 27 becquerels per 1 cc of water, both lower than levels detected in a check of samples taken April 13.
TEPCO believes no additional leaks of radioactive materials have taken place at the reactor.
It said the radioactive materials detected in the latest check could have come from seawater sprayed into the pool to cool the reactor.
Seawater in the vicinity of the plant has been contaminated by radiation leaked by the facility.

http://www.asahi.com/english/TKY201104300099.html

 

[dh87]

8-day halflife for iodine-131.

The striking thing is that I-131 has been going up for the last week at unit 3, without cesium increasing at the same rate. Indeed, some of those days, the cesium activity decreased.

Soil chemistry is complicated. But the most obvious process replenishing I-131 would be uranium fission.

Graph #2 in this set (http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110501e6.pdf) shows I-131 and Cs-137 diverging, with I-131 rising and Cs-137 falling. I believe that these measurements are less direct than the sub-drain measurements that you referred to earlier. This divergence might be accounted for by other factors (like the zeolite TEPCO put in the ocean). Still, it doesn't look like evidence that everything is going well.

 

[fluutekies]

Please, can somebody calculate the energy output of a reaction which ends with x Bq iodine?

I assume you mean I-131 from fission of U-235.

The fission yield is: 2.878% (wikipedia)

Specific activity: 4598.8 TBq/g http://www.wolframalpha.com/input/?i=Iodine-131

x Bq I-131 = x * 4.5988*10^-15 g I-131

Does that answer your question?

 

[Rive]

Does that answer your question?

Nope I (you) need an energy equivalent.

x Bq I131 = y J.

 

[fluutekies]

Nope I (you) need an energy equivalent.

x Bq I131 = y J.

Then calculate amount U-235 needed and use fission energy.

 

[Jorge Stolfi]

OK, here are the Mickey Mouse pics again:
[PLAIN]http://www.ic.unicamp.br/~stolfi/EXPORT/projects/fukushima/povray/blueprint/foto/edited/src/reactor4-E-scaff-2.png[PLAIN]http://www.ic.unicamp.br/~stolfi/EXPORT/projects/fukushima/povray/blueprint/foto/edited/out/reactor4-E-scaff-2-A-e.png

(A) I see there a tank - white, cylindrical, horizontal, with two hemispherical caps. But there may be something else at the North (right) end.

(B) Seems to be a platform below the tank, with a railing and/or some equipment hiding the lower parts of the tank.

(C) The central part of the scaffold seems to be offset to the East. A ladder or stair leading to the platform (B), perhaps?

(D) Projection of floor 4 on the outside of the east wall. I have truncated the line for clarity; AFAIK the 4th floor slab spans the whole building, up to the corner, except for the reactor and SFP cavities. (Floor 5, the service floor, is level with the pipe running across the wall.)

(E) Projection of floor 3 on the outside of the east wall. The projection is actually hidden behind the turbine building.

I was surprised at the position of floors 3 and 3 in this picture; I was expecting them to be a bit higher. But that is what the blueprints and my arithmetic say.

[PLAIN]http://www.ic.unicamp.br/~stolfi/EXPORT/projects/fukushima/povray/blueprint/foto/edited/src/reactor4-E-scaff-4.png[PLAIN]http://www.ic.unicamp.br/~stolfi/EXPORT/projects/fukushima/povray/blueprint/foto/edited/out/reactor4-E-scaff-4-A-e.png

(A) I guess the two ends of the tank are here.

(B) My guess is that this dark spot is a piece of equipment or scaffolding in front of the tank.

(C) This blurred spot is where the top of the staircase should be. It may have been lost by the MPEG encoding.

(D) These seem to be the pipes/cables that, in latter pictures, connect to the Big Grayish Closet on the south wall of the building, below the window. Does it mean that the Big Grenish Closet is not the Mickey Mouse scaffolding, but a separate Mystery?

(E) Corner line of the main building. It actually extends all the way down to (C), the parapet of the terrace.

(F),(G),(H) - projections of floors 5 (service), 4, and 3 on the outer face of the East wall, computed from the blueprints.

(I) Possible roof or raised floor above the terrace floor.

According to the blueprints, floor 3 should be at the same level as the floor of the terrace in question. Yet in this photo the latter seems to be a couple of meters higher than floor 3. Perhaps there is a roof or raised floor on the south half (I) of the terrace, around the air condintioning units?

If the concrete floor of the terrace is indeed at level (H), then the Mickey Mouse structure is probably taller than we thought; perhaps 8 meters or more.

 

[dh87]

From new nisa report we can see that all temperatures are going up...

Do you have a link to this report?

 

[MadderDoc]

Article 2011/05/01 from The Asahi Shimbun regarding the image of fuel rods in SFP4.
http://www.asahi.com/english/TKY201104300099.html

"The image showed the status of the storage pool about six meters below the surface of the water."

Curious. In the video, we see no change in visual field, neither during the putative 6 meter submersion of the camera, nor, during its 6 meter retraction from the water. The framerate of the video is 30 frames/second, so if the complete submersion/ retraction should have occurred between one frame and the next we would be looking at a speed of the tip of the concrete pump during the submersion/retraction, of at least 6 meter/0.03 seconds = 200 m/s. That's 730 km/h, or appr. 500 mph!

 

[MiceAndMen]

No malice was intended. I honestly don't think it is possible to get the replacement core shroud through that hole in the wall in one piece. And even if you managed to do so, the troubles getting it to the service floor would not end there ..

None taken I was simply defending my idea that the core shroud could fit through a hole of that size in response to your picture that suggested it was impossible due to physical size constraints. There are good arguments against that being the actual ingress point for the new core shroud, but, "It won't fit," isn't one of them.

It is curious that with all the technical details we know of the shroud replacement procedure, that we don't know how the shroud gets to the service floor. Do we know that it is being brought in, in one piece? From diagrams I've seen, the construction of the shroud itself involves the welding together of several cylindrical 'slices'.

My central contention in all this is that the green box/framework/hole thing could have had something to do with the core shroud replacement project, not that that spot was definitively the location of core shroud ingress. I really don't care how they got them in and out of the building. The core shroud replacement job is much more than a routine refueling outage. There must be (literally) tons of extra equipment and tools needed above and beyond what's normally in the reactor building, and maybe whatever was happening on the low roof in the SE corner of the building was in a support role for all that extra stuff.

The explosions in buildings 1 and 3 have been attributed to a buildup of H2 gas that escaped from primary containments. The etiology of the building 4 explosion must have been very different. Did the green box/framework/hole apparition and/or the core shroud replacement work contribute to the explosion of building 4? I think we're no closer to answering that question than we were on 12 March.

 

[elektrownik]

Do you have a link to this report?

http://www.meti.go.jp/press/2011/05/20110501003/20110501003-3.pdf
Report number & temperature reactor 1:
119 - 107,3 C
120 - 114,7 C
121 - 131,2 C
122 - 142 C
But also other units temperature increase, but not so quick like 1.
This is strange, for example there wasnt change in pressure and water injection level but temperature changed from 114 to 131 and from 131 to 142...

 

[tadjik]

http://www.meti.go.jp/press/2011/05/20110501003/20110501003-3.pdf
Report number & temperature reactor 1:
119 - 107,3 C
120 - 114,7 C
121 - 131,2 C
122 - 142 C
But also other units temperature increase, but not so quick like 1.
This is strange, for example there wasnt change in pressure and water injection level but temperature changed from 114 to 131 and from 131 to 142...

Water injection has been slowed, I think. At least for unit 1.
http://www.bloomberg.com/news/2011-04-29/tepco-slows-water-injection-at-reactor-to-curb-risk-of-explosion.html

 

[Dmytry]

Heat up, fission products, etc: Maybe they ran out of boron.

Nope I (you) need an energy equivalent.

x Bq I131 = y J.

Re: the energy output required to make a specific amount of iodine through fission:

http://en.wikipedia.org/wiki/Iodine-131
I-131 yield in fission = 0.029 [slightly dubious 'cause it varies to neutron energy, but should be in this ballpark]
fission:
http://en.wikipedia.org/wiki/Uranium-235
energy yield: 2E8 eV per fission
energy per atom of I-131 = 2E8/0.029 = 6.9E9 eV
There has to be
t_1/2/ln(2) atoms per Bq which, for i-131, is very nearly 1E6 atoms per Bq.
http://www.wolframalpha.com/input/?i=((8.0252+days)/ln(2))/second

The fission energy per Bq of I-131 is then 1.1E-3 J
http://www.wolframalpha.com/input/?i=(((8.0252+days)/ln(2))/second)*(6.9E9+eV)

100KW of fission, for 1 day, makes 7.8E12 Bq of I-131.
http://www.wolframalpha.com/input/?i=(100kw*1+day)/((((8.0252+days)/ln(2))/second)*(6.9E9+eV))

edit: note, noscript strips parens out of the url. The final formula is:
(100kw*1 day)/((((8.0252 days)/ln(2))/second)*(6.9E9 eV))

you guys do the concentrations and volumes, it's late night here. I didn't check my sources, so beware.

 

[MadderDoc]

(D) These seem to be the pipes/cables that, in latter pictures, connect to the Big Grayish Closet on the south wall of the building, below the window. Does it mean that the Big Grenish Closet is not the Mickey Mouse scaffolding, but a separate Mystery?

Yes, it would appear so, and there's more.. I found a third image of reasonable resolution taken on March 12th, apparently on the same overflight as the photo you are looking at. This new photo is looking in from SW, giving a good view to the corner by that window. Here's a blow up of that part, find links to the source and the original image below.

There's the big green closet, if I am not mistaken, at the window. Furthermore, look to the left of the window, at ground level as best we can see in the photo. There appears to be yet _another_ albeit smaller 'closet', standing apparently flush to the south wall of the reactor building, close to its SE corner. The original photo is at:
http://www.pbs.org/wgbh/nova/insidenova/04_42-27775632.jpg
linked from the page at:
http://www.pbs.org/wgbh/nova/insidenova/2011/03/earthquake-geology.html

 

[Cainnech]

"The image showed the status of the storage pool about six meters below the surface of the water."

Curious. In the video, we see no change in visual field, neither during the putative 6 meter submersion of the camera, nor, during its 6 meter retraction from the water. The framerate of the video is 30 frames/second, so if the complete submersion/ retraction should have occurred between one frame and the next we would be looking at a speed of the tip of the concrete pump during the submersion/retraction, of at least 6 meter/0.03 seconds = 200 m/s. That's 730 km/h, or appr. 500 mph!

Well, my native language isn't english, but the way a read that sentence was something like this:
"The image showed the status of the top of the fuel rods located about six meters below the surface of the water."

So in other words they put the camera in the pool. Submersed it a bit. Took some pictures and then got the hell out of there.
And somehow they knew that that the depth where the top of the rods where was about six meters.
I hope this clears it up a little.

 

[MadderDoc]

<..>maybe whatever was happening on the low roof in the SE corner of the building was in a support role for all that extra stuff.

Yes, that's also the direction my thoughts are going in after all the photo-twitching. There's an endpoint of a 66kV line on a big transformer in that corner, and a bunch of wires seems to lead from the different boxes and closets we have looking at in the direction of that transformer. The support role could be to serve a need for supply of extra electricity.

The explosions in buildings 1 and 3 have been attributed to a buildup of H2 gas that escaped from primary containments. The etiology of the building 4 explosion must have been very different. Did the green box/framework/hole apparition and/or the core shroud replacement work contribute to the explosion of building 4? I think we're no closer to answering that question than we were on 12 March.

The possibility that the 'hole' was indeed a hole was what sparked my interest in it. It would have been an indication of earthquake damage quite close to the SFP, and damage to the SFP area could have led to its leaking faster, ultimately leading to overheating, hydrogen production, and boom. But, as we have uncovered, the evidence does suggest another explanation of the whole mickey.

 

[MadderDoc]

Well, my native language isn't english, but the way a read that sentence was something like this:
"The image showed the status of the top of the fuel rods located about six meters below the surface of the water."

So in other words they put the camera in the pool. Submersed it a bit. Took some pictures and then got the hell out of there.
And somehow they knew that that the depth where the top of the rods where was about six meters.
I hope this clears it up a little.

It certainly does, and I am happy to accept your alternative interpretation, because however fine machines these concrete pumps are, they couldn't possibly move their 'trunk' at that speed, I just couldn't make that fit.

 

[Jorge Stolfi]

Does anyone have any reliable info on the nuclear plants - the reports on the news seem garbled to me.

This was the very first post on this trhread, 50 days and 5500 posts ago. It still seems quite relevant...

 

[triumph61]

Yes, it would appear so, and there's more.. I found a third image of reasonable resolution taken on March 12th, apparently on the same overflight as the photo you are looking at. This new photo is looking in from SW, giving a good view to the corner by that window. Here's a blow up of that part, find links to the source and the original image below.

There's the big green closet, if I am not mistaken, at the window. Furthermore, look to the left of the window, at ground level as best we can see in the photo. There appears to be yet _another_ albeit smaller 'closet', standing apparently flush to the south wall of the reactor building, close to its SE corner.


The original photo is at:
http://www.pbs.org/wgbh/nova/insidenova/04_42-27775632.jpg
linked from the page at:
http://www.pbs.org/wgbh/nova/insidenova/2011/03/earthquake-geology.html

At the Original Foto, the Truck in Unit4 is not to see, the Door is closed.

 

[robinson]

This was the very first post on this thread, 50 days and 5500 posts ago. It still seems quite relevant...

Indeed, indeed. Some of the other comments from the first days are quite interesting in retrospect. It's tiresome but illuminating to read back in the thread.

 

[Reno Deano]

At the Original Foto, the Truck in Unit4 is not to see, the Door is closed.

Is that a person standing on the knoll in the far right of the picture?

 

[clancy688]

[PLAIN]http://www.ic.unicamp.br/~stolfi/EXPORT/projects/fukushima/povray/blueprint/foto/edited/out/avg-090-099-c-A-i.png

(C) Osama bin Laden, no doubt about it.

Did you already collect your 25million $ reward for reporting Osama bin Ladens location to the US...?

 

[NUCENG]

An underwater video of the #4 SFP (110428_1.zip) was recently posted on this thread.
I extracted the frames with

ffmpeg -i video.mpg -vcodec png frames-b/%08d.png

(The "-vcodec png" option and png output format apparently gives better images than the default extraction to JPEG format; the latter has a good amount of the 8x8 JPEG block noise).

Then I randomly picked 10 successive frames (90-99), aligned them manually, averaged them, and applied some brightness/contrast correction to each channel. Here is the result:
[PLAIN]http://www.ic.unicamp.br/~stolfi/EXPORT/projects/fukushima/povray/blueprint/foto/edited/src/avg-090-099-c.png
I am sure one can get much sharper images out of that video, with better processing tools. (Again, I don't see why one should take a low-res video from a static target, rather than a few high-res photos. Sigh.) There is much image deformation by thermal gradients in the water; the water must be boling inside some racks.

Some notes:
[PLAIN]http://www.ic.unicamp.br/~stolfi/EXPORT/projects/fukushima/povray/blueprint/foto/edited/out/avg-090-099-c-A-i.png

(A) These bumps on the rack edges are normal features of the racks, correct? Why do the ones in row n-2 look different from those in row 2?

(B) This streak is the result of averaging the motion of a floating object (paint flake?)

(C) Osama bin Laden, no doubt about it.

EDIT: It turns out that frames 90-99 are particularly bad. Frames 40-63 are much better. I should try again with those.

From the latest from the WH, it may not be Osama after all. ;-}

 

[razzz]

From the latest from the WH, it may not be Osama after all. ;-}

'B' is a jellyfish...

 

[jlduh]

8 workers to enter building of reactor N°1 Thursday...
http://www3.nhk.or.jp/daily/english/02_11.html

Tepco doesn't precise if these will be Tepco employees or "Jumpers" paid 5000 dollars a day.

 

[~kujala~]

Regarding the number 6 reactor:

The transfer of accumulated water in Unit 6 turbine building to a
temporary tank was conducted from 2:00 pm to 5:00 pm on May 1 and the
transfer was started from 10:00 am, May 2.

https://www4.tepco.co.jp/en/press/corp-com/release/11050202-e.html

Unit 6:
At this moment, we do not consider any reactor coolant leakage inside the
reactor happened.

TEPCO doesn't say here that the water is highly radioactive. Perhaps the reporter made a mistake in the NHK News and confused with the number 2 and 6 reactor wastewater radioactivity levels?
http://www3.nhk.or.jp/daily/english/01_15.html

My guess is that the water in the number 6 turbine building is groundwater infiltrating into the basement and it is low-level contaminated. They have had problems with groundwater earlier in the 5 and 6 units:

NISA said underground streams are a possible source. Before the crisis, streams beneath reactors No. 5 and 6 were pumped to divert water, a process that hasn't been conducted since the quake.

http://online.wsj.com/article/SB10001424052748703922504576273930625967622.html

The contamination may have come mainly from airborne radiation which has taken some time to be seen in groundwater. The only thing that remains a bit of mystery is the rising of radioactivity levels on the 20th of April.

 

[rowmag]

From the latest from the WH, it may not be Osama after all. ;-}

Loch Ness Monster?
Yeti?
Crashed UFO?

It would help if we had some really grainy, fuzzy black-and-white images of the SFP to compare with historical records on the above potential candidates.

 

[elektrownik]

Reactor 3 temperature jump:
-nisa 122: RPV 138C
-nisa 123: RPV 188C

 

[MiceAndMen]

I promised myself I would refrain from ranting any more about TEPCO in this thread, but their strategy eludes me. I don't understand what they hope to accomplish on the ground floor of the reactor buildings besides finding more leaks. The problem is 30 meters up, and I would think affixing radiation monitors and cameras up on the blown out superstructure is where they should be concentrating their attention. It's almost as if they are afraid to do anything up top except for pumping water from a distance. Their plans are rooted in fantasy and designed for public relations more than addressing the problems IMO.

 

[imandylite]

I promised myself I would refrain from ranting any more about TEPCO in this thread, but their strategy eludes me. I don't understand what they hope to accomplish on the ground floor of the reactor buildings besides finding more leaks. The problem is 30 meters up, and I would think affixing radiation monitors and cameras up on the blown out superstructure is where they should be concentrating their attention. It's almost as if they are afraid to do anything up top except for pumping water from a distance. Their plans are rooted in fantasy and designed for public relations more than addressing the problems IMO.

The mindset is one of 'must get these reactors under control'.

It seems to be an inability to accept the failures that have occurred and the logical conclusion that the plant needs to be buried in sand and concrete.

This is what happens when you keep telling yourself and those around you one thing and accordingly put all your eggs in one basket - failure just is too terrible to accept.

 

[MiceAndMen]

The mindset is one of 'must get these reactors under control'.

It seems to be an inability to accept the failures that have occurred and the logical conclusion that the plant needs to be buried in sand and concrete.

This is what happens when you keep telling yourself and those around you one thing and accordingly put all your eggs in one basket - failure just is too terrible to accept.

I guess, but burying them is premature until they know exactly what they're dealing with, and they don't seem to be in any rush to find out.

Unit 1: Assign a robot to the collapsed roof to move about and take radiation measurements. If the robot fails due to radiation, put another one up there. How are they getting water into the #1 SFP right now? Is the closed-loop cooling circulation system working?

Unit 2: There is a gaping hole in the western face of the building. The roof is intact. Get a crane and deploy a robot in there ASAP.

Units 3 & 4: Get someone or something to emplace radiation monitors on the exposed steel beams of the upper superstructure. When it's safe enough to work, get some guys up there with torches to start cutting the debris away. Find 200 ironworkers and let each of them cut one beam. If it takes an hour to cut a beam and the safe exposure is 30 minutes, then find 400 workers. Find 2,000 for crying out loud, and get them up there.

 

[elektrownik]

OMFG: BREAKING NEWS: Radiation leaks from fuel rods suspected at Tsuruga plant: local gov't:

 

[Samy24]

Reactor 3 temperature jump:
-nisa 122: RPV 138C
-nisa 123: RPV 188C

SFP unit 1 FPC skimmer level
-nisa 115: 4550
-nisa 123: 1650

Does this mean the pool is running dry in unit 1? Who knows? Maybe all the data in these reports do not say anything?

 

[Borek]

OMFG: BREAKING NEWS: Radiation leaks from fuel rods suspected at Tsuruga plant: local gov't:

http://af.reuters.com/article/energyOilNews/idAFL3E7G214720110502

Internal leak - from rods to coolant, from what I understand there is no leak to the outside of the plant.

 

[MiceAndMen]

A very good report from the Associated Press...

http://www.blueridgenow.com/article/20110502/API/1105020602

After reading it, I feel much more confident that TEPCO and the Japanese nuclear industry are capable of dealing with the situation at the Fukushima Daiichi NPP.

[Note: sarcasm is not always readily apparent on the internet. This article has all the earmarks of a "wrap-up" story, which means the daily media coverage of the situation has come to an end barring some dramatic development that will boost ratings.

 

[jpquantin]

SFP unit 1 FPC skimmer level
-nisa 115: 4550
-nisa 123: 1650

Does this mean the pool is running dry in unit 1? Who knows? Maybe all the data in these reports do not say anything?

There is a contradiction between these datas and no report about spraying in SPF1.

From the various report, the SPF level is reported to go from 4550 (Apr 26 5:00) down to 1900 (May 01 11:00).

AFAIK surface of SPF1 is around 86 meters^2 (same height as SPF2 to 5, but less volume => data taken from http://allthingsnuclear.org/post/4008511524/more-on-spent-fuel-pools-at-fukushima" ).

This is 2.65 meters of water having left the pool, this is about 229 tons, in exactly 126 hours. Which gives an average of 1.8 tons per hour.

Again somewhere in http://allthingsnuclear.org/tagged/Japan+nuclear/page/2" , boiling in SPF1 would come from a 60 Mcal/hour power, which gives a rate of 0.11 tons per hour.

Conclusion: the drop cannot be explained by boiling. Moreover, this SPF was "quiet" before Apr 26 (no change in level, no report of water spread in SFP - does not mean there had been none).

There may be accelerated leak (from Apr 26 - BIG leak), or additional heat. Edit: no report of white smoke above unit 1.

Worth noticing is the rate the concrete pump can put water in. In SPF4, they have sprayed 960 tons in 1717 minutes since Apr 19, which gives a rate of about half a ton per minute, or about 30 tons per hour.

Putting everything together, we have:
- of course they are aware of SPF1 level drop
- they are injecting water as fast as they can (?) Since no report on spraying at SFP1 ... They may be able to do at 30 tons per hour, and however pool level drops.
- SPF1 pool level may soon come to top of fuel rods. If all maths and data are correct, we can predict it will be the case at 5AM on May 5th. Edit : except if "BIG leak hole" is above top of fuel rods.
- however no PR about this, nothing in reports ?

EDIT: PFC skimmer level may not give level in SFP itself (to be continued)

 

[Jorge Stolfi]

Did you already collect your 25million $ reward for reporting Osama bin Ladens location to the US...?

I am checking whether the reward terms specify "before the US finds him". Meanwhile, consider this:
(1) News reports say that the body was dumped into seawater somewhere. Nowhere it said it was not borated seawater.
(2) I read on twitter that his hideout had walls 4m thick. Check the SFP walls on the blueprints.

 

[Dmytry]

Reactor 3 temperature jump:
-nisa 122: RPV 138C
-nisa 123: RPV 188C

Hmm. Is there any official denial out yet?

jpquantin: skimmer would not get re-filled if the pool is below the skim level, right? The skimmer is an overflow tank of some sort.

 

[jpquantin]

Hmm. Is there any official denial out yet?

jpquantin: skimmer would not get re-filled if the pool is below the skim level, right? The skimmer is an overflow tank of some sort.

Well agree with you (found skimmer illustrated in http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110418e5.pdf" from Tepco). Do you mean skimmer level does not give SFP level ?

 

[Samy24]

Hmm. Is there any official denial out yet?

jpquantin: skimmer would not get re-filled if the pool is below the skim level, right? The skimmer is an overflow tank of some sort.

Where is the water in the skimmer surge tank going? Why are they releasing this water? Does not matter, but just curious.

 

[TCups]

Alternatively, it may be better for someone to initiate a new thread concerning "unresolved questions about the Fukushima event", and that thread can be stickied in the forum. We could divide the thread into groups of 30 or so pages (1-30, 31-60, . . ) or groups of 25, and ask folks to browse the pages for unresolved questions. We could then link back to the thread/posts. Alternatively, it may be better for those asking questions to determine if their particularly question remains unresolved.

Sorry to be running so far behind -- PF seems to be having server problems that coincide with my reading time.

What would be most helpful is a sticky that has, without additional interpretation, and indexed as appropriate (including location, date and time), links and graphics (with original source and copyright data) of:

1) technical drawings and diagrams of the physical plan at Fukushima

2) photos and videos of Fukushima

3) relevant tables, graphs & charts (ie, of radiation measurements, RPV and SFP parameters, etc.)

4) links to related articles

Going forward, perhaps posters could include such appropriate links and attachments, not only in their posts, but also appended to the appropriate sticky.

This thread is an amazing source. It deserves to be indexed and footnoted and perhaps, technically edited to better organize and categorize the content. I predict it will be a long-lasting source for technical and historical research.