Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[zapperzero]

http://youtu.be/kO0flpwmjJI

Can anyone translate this videos?

Yep. http://ex-skf.blogspot.com/2011/04/fukushima-i-nuke-plant-ishikawa-of-jnti.html" did.

 

[georgiworld]

Yep. http://ex-skf.blogspot.com/2011/04/fukushima-i-nuke-plant-ishikawa-of-jnti.html" did.

What about the video you posted and I mistakenly re-posted? Is there a translation of that?

 

[rowmag]

Can't be. The number of channels in the core where bundles (assemblies) go is fixed, no?

I think they meant that they were replacing some low-gadolinium assemblies with the new ones.

 

[MadderDoc]

Well, the mystery thickens.<..>
What was the date of the photo showin the Mickey Mouse ears?

It was March 11th, at approximately 16:00. It is a frame from the video shot from a helicopter shortly after the tsunami, see for example this version of the video:
http://www.dailymotion.com/video/xhsf3e_new-film-of-tsunami-aftermath_news

There's perhaps disappointingly little mystery in it. If one takes account of the poor quality of the video from March 11th, and its being shot in a more oblique angle, it appears to be showing the same as the photo we have from March 12th:

Note: The image in the center has been subjected to the shearing/perspective tools of Gimp, in order to correct for the more oblique angle it was taken, so as to ease comparison.

 

[rowmag]

No way it would be extream radioactive, and it would melt without cooling.
About unit #4. This is possible that they were repleacting core shroud, reactor 4 was shout down and defueled becouse there was some crack in core shroud, so this would be possible that they were repleacing it. There is no much space, but look on this photo:

That is a water heater (pre-heater?) that is being replaced with a more corrosion-resistant type.

 

[rowmag]

As for the route from unit 2 to the waste treatment facility...

From these pictures one can see that the route from unit 2 trench to the facility goes through/near 2, 3 and 4 turbine buildings:
http://varasto.kerrostalo.huone.net/pump_route.jpg
http://varasto.kerrostalo.huone.net/pump_route_2.jpg

Here is the text related to these pictures:
http://www.ordons.com/asia/far-east/24807-tepco-to-accelerate-transfer-of-radioactive-water.html

So if the hoses are leaking you never know where the water is going to end.

They did that on purpose, so that if the hose did spring a leak, it would leak into the turbine buildings instead of onto open ground.
(Source: the nightly news a while back.)

 

[Joe Neubarth]

Also these might have caused the http://varasto.kerrostalo.huone.net/sub_drain_spike.png" on the 20th of April in units 1, 3, 4 and 6:


http://www.nisa.meti.go.jp/english/files/en20110430-3-2.pdf

As for the route from unit 2 to the waste treatment facility...

From these pictures one can see that the route from unit 2 trench to the facility goes through/near 2, 3 and 4 turbine buildings:
http://varasto.kerrostalo.huone.net/pump_route.jpg
http://varasto.kerrostalo.huone.net/pump_route_2.jpg

Here is the text related to these pictures:
http://www.ordons.com/asia/far-east/24807-tepco-to-accelerate-transfer-of-radioactive-water.html

So if the hoses are leaking you never know where the water is going to end.

About the radiation in the number 6 building:


http://www3.nhk.or.jp/daily/english/01_15.html

Is the number 6 leaking also?

Nobody knows for certain. There was conjecture that water was running through tunnels between (1, 2, 3, & 4) and (5 & 6). We know that is a possibility, but we are not certain about the height of the basement of (5 & 6) being the same as the height of the other reactors. One poster maintained that (5 & 6) were considerably higher. If so, then the water in (1, 2, 3, & 4) would be way higher if radioactive water seeks its own level across a common pathway. Hummmmmmmm?

Who is the resident expert here who can explain the heights of the building basements and what is happening?

 

[triumph61]

It was March 11th, at approximately 16:00. It is a frame from the video shot from a helicopter shortly after the tsunami, see for example this version of the video:
http://www.dailymotion.com/video/xhsf3e_new-film-of-tsunami-aftermath_news

There's perhaps disappointingly little mystery in it. If one takes account of the poor quality of the video from March 11th, and its being shot in a more oblique angle, it appears to be showing the same as the photo we have from March 12th:

Note: The image in the center has been subjected to the shearing/perspective tools of Gimp, in order to correct for the more oblique angle it was taken, so as to ease comparison.

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

 

[MadderDoc]

Nice try. According to this http://www.irpa.net/irpa10/cdrom/00584.pdf the core shroud is approximately 4.5 meters in diameter and about 7 meters high. So it would more closely resemble the attached pictures.

View attachment 35063View attachment 35064

It's almost a perfect fit.

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 ..

The amount of room to work between the wall and the SFP could be a problem for this arrangement. That is certainly true. Thus, my thirst for more and better blueprints. I was frankly surprised when I quickly whipped up the core shroud cylinder and placed it on the low roof. There could be other reasons why they needed a 5 x 5 m opening (or whatever it is).

I would put that figure slightly lower at 4 x 4 m, but let's not quarrel about that, I think we can agree that if it is a fit, then it is a tight one.

I think the shape that appears to be a hole in the wall, after the green box has gone, encomprises not just a hole, but also to the right, left and above the actual hole a jagged edge surrounding it, where wall panel paint/concrete has come off. At the bottom edge we have the more massive vertical concrete structure of the wall, roughly corresponding to the separation between 3rd and 4th floor. Visually, after paint and concrete has peeled off of that piece of concrete it is also liable to visually give the appearance as being a part of the hole, but we know for sure, that nothing has made a hole in it (and nobody in their right mind should contemplate to do so, since it would risk compromising the stability of the building.)

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'.

 

[jlduh]

Relatively high levels of Cesium found in the sludge of a waste water treatment plant in Fukushima prefecture at Koriyama (around 60/70kms from the Daichi site):

http://www3.nhk.or.jp/daily/english/01_25.html

 

[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...