Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[MadderDoc]

The explosion could have done that, because the hydrogen-air mix occupies much more volume than the resulting steam. I can't think of anything else.

That would hold true even more for a steam explosion.

 

[MadderDoc]

How much time? We have about a second, second and a half to work with, no?

I am not sure. Nucleation is a function of diffusion rate hence a function of temperature. At relatively low temperatures it is not easy to make water flash to steam.

That's what I meant, when I said this should be experimented upon. But are you sure about the pool water temp? Could easily have been more.

I can't see how, we are only about 70 hours after cooling of the pool was halted. Mind Occam.

I'm reasonably sure that the RPV didn't have that much water in it, in the event :).

No, surely not. But it was just an example, and anyway it was about water in the primary containment, not the RPV. Under normal circumstances the primary containment holds about 3000 cubic meters of water. Not sure how much they lost by vents and how much that was countered by injection of external water. On the face of the pressure data, it might have lost only a few hundred cubic meters of its liquid water as steam in connection with the explosion in unit 3.

 

[zapperzero]

I can't see how, we are only about 70 hours after cooling of the pool was halted. Mind Occam.

Hm. Okay.

On the face of the pressure data, it lost only a few hundred cubic meters of its liquid water as steam in connection with the explosion in unit 3.

And where do you think that went? Up in a mushroom cloud?

 

[zapperzero]

Then I am not sure how you arrived at that figure, and how it landed in the right ball-park range for the volume of steam that can be produced from 1 ton of hydrogen.

PV=nRT. Checked with a steam calculator I found on the web.

Are you a beginner? :-)

In all things, I should hope.

 

[MadderDoc]

Hm. Okay.

And where do you think that went? Up in a mushroom cloud?

Let's see if there is room for more after the hydrogen explosionists have made their claims.

 

[r-j]

Is there some sort of mystery about what blew up building three?

 

[MadderDoc]

Is there some sort of mystery about what blew up building three?

:-) Now mystery is such a strong expression, r-j, but if the keyword is 'up' there may be a thing or two which are not yet fully understood: http://gyldengrisgaard.eu/fuku_docs/unit3cloud45/

 

[Yamanote]

In all things, I should hope.

That's the right way zz, but hard to go...

 

[MadderDoc]

<..>you know the size of the building, so you can get a fair estimate of how fast the ball grows because of also knowing at what intervals the frames are taken.

OK, so I made an overlay of frame 1 with the ball visible, and the next frame color inverted. I assume width of building profile (SE to NW corner) is 55 meter. Pixel distance there is 280 pixels, yielding a pixel resolution of 0.2 m. I assume the photo is not significantly out of aspect vertically/horizontally. The blue color in the overlay represents the apparent growth of the ball in frame 2 relative to frame 1. I measure this to be 30 pixels, or 6 m. Frame rate is 30 fps, so the apparent growth speed of the ball is 180 m/s from frame 1 to frame 2. Seeing limited precision, better to say 2E2 m/s.

In the overlay one can also measure the extension of the ball from the building in frame 1. This yields an apparent growth rate, relative to frame 0, of about 3E2 m/s which is about sonic. It could be this you think of as seeing the (just) supersonic speed of a combined flame/shock front of a detonation. Can you think of it in other ways, too?

 

[Rive]

:-) Now mystery is such a strong expression, r-j, but if the keyword is 'up' there may be a thing or two which are not yet fully understood: http://gyldengrisgaard.eu/fuku_docs/unit3cloud45/

As I recall, the previous 2-3 frames are also parts of the process. The explosion starts with the slight expansion of the (visible parts of) the building, the fire phenomenon comes later.

(When the video were first released I also made some pixel hunting on them (substracting the first frames from each other) but the result was not considered worthwhile or important to be posted. )

 

[zapperzero]

In the overlay one can also measure the extension of the ball from the building in frame 1. This yields an apparent growth rate, relative to frame 0, of about 3E2 m/s which is about sonic. It could be this you think of as seeing the (just) supersonic speed of a combined flame/shock front of a detonation. Can you think of it in other ways, too?

We are in the same ballpark, measurements-wise. There is one more measurement you can take - time and space from the leftmost edge of the blast (as seen in frame 0) to where/when the wall on the opposite side of the building bulges out, nearly reaching the apparent edge of reactor building 2 (frame 2, I believe).

 

[MadderDoc]

As I recall, the previous 2-3 frames are also parts of the process. The explosion starts with the slight expansion of the (visible parts of) the building, the fire phenomenon comes later.

Your reference is to an animation of 1 frame per second of thehttp://gyldengrisgaard.eu/fuku_docs/unit3cloud45/ , counting from the first visible fire phenomenon. Naturally seeing the source is 30 fps that leaves out 29/30th of the frames. The animation could have been made starting one frame earlier, when the first signs of something untoward happening with the building can be seen. But then the animation wouldn't have included any of the frames with the fire phenomenon.

Looking at the earliest initial frames, I don't think we can detect any expansion, as part of the first visible effect on the building. I'd say the strong impression is one of building collapse, i.e. the roof appears to come down, so that the building seems to be shrinking in the vertical direction.

 

[MadderDoc]

We are in the same ballpark, measurements-wise.

I assume we are also in the same ballpark, method-wise. The measurements are made from the thought that they represent the movements of a detonation shock/flame front. Can you think of them as perhaps representing something else?

There is one more measurement you can take - time and space from the leftmost edge of the blast (as seen in frame 0) to where/when the wall on the opposite side of the building bulges out, nearly reaching the apparent edge of reactor building 2 (frame 2, I believe).

That would imply measuring to ill-defined points in the shadow of the building and the developing plumes, it doesn't seem immediately promising to me. What would that measurement be good for?

 

[Rive]

Looking at the earliest initial frames, I don't think we can detect any expansion, as part of the first visible effect on the building. I'd say the strong impression is one of building collapse, i.e. the roof appears to come down, so that the building seems to be shrinking in the vertical direction.

- thanks for the link
- between frames -3 and -2 I think the shape of U3 starts to behave differently than U2's and U4's.

 

[MadderDoc]

- between frames -3 and -2 I think the shape of U3 starts to behave differently than U2's and U4's.

You too? I've had the same thought, Rive, but the signal is so weak, feels like dancing on the thin edge of the DL to base something on it. If other evidence likewise points to the possibility of damage preceding shortly the visible blast -. Hm. The peculiarities of the roof in the SE corner, a big flame in the middle of it, but how did it start, how did it progress.
http://www.gyldengrisgaard.eu/fuku_docs/20120311193727exp2.jpg

 

[MadderDoc]

Unit 4 spent fuel pool

I don't understand Tepco's recent announcement, that no cracks was found in the concrete wall surrounding the SFP of Unit 4.
I thought it to be a ~horizontal crack in that wall, the man in this previously released photo is pointing his hand gadget at. I still can't see what else it could be.

 

[zapperzero]

I assume we are also in the same ballpark, method-wise. The measurements are made from the thought that they represent the movements of a detonation shock/flame front. Can you think of them as perhaps representing something else?

Same method, yes. But no... can't think of anything else.

That would imply measuring to ill-defined points in the shadow of the building and the developing plumes, it doesn't seem immediately promising to me. What would that measurement be good for?

It's unclear, yes. But it would give you another measure of how fast the shock front was. Does it take one frame to reach that other corner, or two?

 

[Uagrepus]

I'd say the strong impression is one of building collapse, i.e. the roof appears to come down, so that the building seems to be shrinking in the vertical direction.

Indeed. Looking at the roof-anchor in the picture (true?), the roof collapsed in the south region also in the first stage of the explosion. The big vertical mushroom afterwards "cleaned" that area then.

After 14 months - is there any consensus if there were at least one or two explosions??
There are indications for two different events in my opinion. The hydrogen burns in the east side of unit 3, where it must have been in high concentrations after the leakage near the lid. In the west-side the hydrogen consentrations should have been lower, but with more oxygen there a bit more explosive (the west-wall was blown away, the east-wall remains partially).

Like at the lid of a cooking pot, the hydrogen escapes in an angle when under high pressure. Sorry for my english, look at my next picture:

Could this be an explanation for the fireballs (1A, 1B) in south-east and north-east? The enormous mushroom developed in the geometrical middle between those two fireballs from the perspective of the video. This is at the same time the location of the SPF. The heavy vertical blast (2) seems to be a secondary event, initialized by 1A and 1B. If it is not related to the SPF itself (but I think so), the only explanation that comes to my mind is the more explosive H2/O2-Concentration in the west-side of unit 3.

 

[MadderDoc]

Uagrepus, thanks for your well-argued reply. I read it mainly thinking yes,yes, yes. Rather than going into some detail of difference, I'll add the thought, that the sudden development of a leak in the primary containment top (say, a manhole in the PCV lid sprang open) might go a long way explaining the whole thing. The expected outcome of such occurrence would be a jet of H2 and steam, shortly followed by a whoosh of steam and superheated water, all making its way, up, through whatever passageway it could find through the concrete shield plugs and gate areas.

(To that. add the fair assumption in consistence with consensus, that previous hydrogen leakage had made a chemical hydrogen bomb out of the building, and it suddenly exploded)

 

[MadderDoc]

Same method, yes. But no... can't think of anything else.

The method assumes that the burning airmass is stationary. How did the airmass get there?

It's unclear, yes. But it would give you another measure of how fast the shock front was. Does it take one frame to reach that other corner, or two?

I can't see how it can be done to be of any use. Mind the perspective.

 

[SteveElbows]

I don't understand Tepco's recent announcement, that no cracks was found in the concrete wall surrounding the SFP of Unit 4.
I thought it to be a ~horizontal crack in that wall, the man in this previously released photo is pointing his hand gadget at. I still can't see what else it could be.

Given that the published title of that photo was 'The original place of installation of air-conditioning ducts', I assume he is pointing at where the ducts were originally present. I certainly don't see enough detail in that photo to even begin to assume that we see any cracks there.

 

[MadderDoc]

Given that the published title of that photo was 'The original place of installation of air-conditioning ducts', I assume he is pointing at where the ducts were originally present. I certainly don't see enough detail in that photo to even begin to assume that we see any cracks there.

Wonderful :-) You are one rock of skepticism.

Here's another photo from another angle showing a bit more detail (in upper right in the photo), of the left end of the alleged crack:

 

[zapperzero]

The method assumes that the burning airmass is stationary. How did the airmass get there?

It is only stationary in that the center remains fixed. Otherwise, the shock front would be pushing hydrogen-laden air ahead of it and leaving steam behind, until there was no more hydrogen left.

I can't see how it can be done to be of any use. Mind the perspective.

Yes, it's not very clear.

 

[MadderDoc]

It is only stationary in that the center remains fixed. Otherwise, the shock front would be pushing hydrogen-laden air ahead of it and leaving steam behind, until there was no more hydrogen left.

Should measurement then not be from the center, to the edge, rather than from edge to edge? Does air in front of a detonation shockwave 'know' that the shockwave is coming?

 

[Rive]

Here's another photo from another angle showing a bit more detail (in upper right in the photo), of the left end of the alleged crack:
[/QUOTE]
Where were these photos taken? The recent announcement was only about checking the walls around and supporting the fuel pools as I recall.

 

[SteveElbows]

Recently I have been speaking on the thread about reactor 2 releases, about this TEPCO report on total radiation estimates. We heard about the totals, but there are some interesting details in the full report. It doesn't sound like TEPCO are going to translate the full document, so this is an appeal for help in translating interesting bits.

http://www.tepco.co.jp/cc/press/betu12_j/images/120524j0105.pdf

A good starting point would be the table on page 9 which shows estimated releases of different substances during a range of different time periods/events. Not hard to understand most of it without proper translation, apart from the notes column.

Anyway I think this table should be of particular interest because for once it does not stop looking at detail after the explosions have finished, the dates March 16th to March 29th are represented here! For example reactor 3 gets some credit for some notable releases on march 16th and march 19th.

Those with an interest in weather may like many of the diagrams later in the report, and MadderDoc may be amused to note that when they talk about non-vent releases from containment, they use a thermal image of reactor 3 to acknowledge the issue. There are some diagrams of the engineering detail of potential weak-spots but they aren't very good resolution and we've seen at least some of them before.

 

[MadderDoc]

Where were these photos taken? The recent announcement was only about checking the walls around and supporting the fuel pools as I recall.

They are from the west wall of the pool, 4th floor, the same wall section which the recent announcement is showing a lower portion of in a sharp angle, the photo bottom right in
http://2.bp.blogspot.com/-e4hpgfA9W...jMc2lWo/s1600/fukushimareactor4SFPMay25-7.JPG

(The photos are from the original survey of Unit 4 damages done in Nov. 2011, source:
http://photo.tepco.co.jp/en/date/2011/201111-e/111110_01e.html)

 

[MadderDoc]

<..>http://www.tepco.co.jp/cc/press/betu12_j/images/120524j0105.pdf<..>
Anyway I think this table should be of particular interest because for once it does not stop looking at detail after the explosions have finished, the dates March 16th to March 29th are represented here! For example reactor 3 gets some credit for some notable releases on march 16th and march 19th.

Those with an interest in weather may like many of the diagrams later in the report, and MadderDoc may be amused to note that when they talk about non-vent releases from containment, they use a thermal image of reactor 3 to acknowledge the issue. There are some diagrams of the engineering detail of potential weak-spots but they aren't very good resolution and we've seen at least some of them before.

Actually those engineering details I found pretty interesting, or at least, new. Indeed there was a scent of what the Tepco cat could tell.

Otherwise, I got just the scent of the bones of the same old whale, the data from the monitoring posts. Apparently Tepco has set out to put a label and some figures on any major signal from that data series, however the soup of words that came out of it defies their own reasonable efforts to translate or express it in plain English in such manner as to be well taken internationally.

 

[Rive]

The previously mentioned press visit videos are now out: http://photo.tepco.co.jp/en/date/2012/201205-e/120526-01e.html

They have found a water inflow to the U3 buildings: http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_120526_01-e.pdf

And a survey about U1, without any immediate revelations: http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_120525_06-e.pdf

Some fuel will be removed from U4 pool in July: http://www3.nhk.or.jp/daily/english/20120528_09.html

 

[Rive]

(The photos are from the original survey of Unit 4 damages done in Nov. 2011, source:
http://photo.tepco.co.jp/en/date/2011/201111-e/111110_01e.html)

It's hard to put these pictures together, but the curved wall on this photo: http://gyldengrisgaard.dk/fuku_docs/111110_06.jpg
suggests that the wall section here: http://photo.tepco.co.jp/library/111110/111110_12.jpg belongs to the 'neck' between the pool and the well.

This section is marked as 'checked' in the 'soundness' document. And you are right, that line on the wall looks like a crack.

The only thing I can think is that the crack was smaller than 1mm and there was no danger of rebar corrosion... They can be right with these but even so it won't make me happy.

 

[MadderDoc]

It's hard to put these pictures together, but the curved wall on this photo: http://gyldengrisgaard.dk/fuku_docs/111110_06.jpg
suggests that the wall section here: http://photo.tepco.co.jp/library/111110/111110_12.jpg belongs to the 'neck' between the pool and the well.
This section is marked as 'checked' in the 'soundness' document. And you are right, that line on the wall looks like a crack.


The only thing I can think is that the crack was smaller than 1mm and there was no danger of rebar corrosion... They can be right with these but even so it won't make me happy.

You are right about the location. The pixel resolution of these images is about 10 mm and we see rust stain originating from one area of the crack. The crack in the wall was visible already in the first images I saw from the 4th floor of Unit 4, but it didn't really bother me, since cracks in a steel reinforced concrete building after an explosion was sort of what I expected to see. I take note of it only because the recent announcement seems inconsistent with already acquired knowledge. My brain works like that, sorry. Here's a detail from the first image of the wall as it looked in June 2011:
http://gyldengrisgaard.eu/fuku_docs/110611_05_detail.jpg
source Tepco, at http://photo.tepco.co.jp/en/date/2011/201106-e/110611-03e.html


Footage from the most recent press tour shows scaffolding and a ladder leading to the area of the crack, I guess they may have been puttying it.
http://gyldengrisgaard.eu/fuku_docs/Unit4_4th_scaffold.png

 

[Rive]

The pixel resolution of these images is about 10 mm and we see rust stain originating from one area of the crack.

The image resolution does not matter much for this one: on a photo every crack will look much wider than it really is due the painting/surface pieces of the concrete will be dislocated much wider range than the distance between the main bodies. This can be measured with probes only.

The rust also can be originated from rebars or anything close to the surface. Its presence does not mean that the structure is in danger in depth.

I think this is the point where we won't get enough information from the pictures to move further. However it's worrying that these cracks are not mentioned in the documents, even if they are thought to be safe/too small/irrelevant.

Ps.: about the press visit video: funny, now they have some heavy machinery on the top level and much more stuff 'missing' there than on the previous photos...

 

[Rive]

... the fireballs (1A, 1B) in south-east and north-east?

Based on the remnants of U4 top section, the double fireballs IMHO are most likely originated from between north/south wall and roof, and not necessarily from the corners. I think the suggested concentration differences are not necessary to explain the result.

It appears to me that these walls (and their weak/nonexistent connection to the roof) are the weak points of the secondary containment of this reactor type.

 

[turi]

[...]
And a survey about U1, without any immediate revelations: http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_120525_06-e.pdf[...]

Thanks for the link. Does anyone know what the vertical orange "thing" in the unprocessed image is? The processed image doesn't have such an artifact. What kind of processing is done anyway? Adjustment for the distance of the radiation source from the camera?

 

[MadderDoc]

The image resolution does not matter much for this one: on a photo every crack will look much wider than it really is due the painting/surface pieces of the concrete will be dislocated much wider range than the distance between the main bodies. This can be measured with probes only.

The rust also can be originated from rebars or anything close to the surface. Its presence does not mean that the structure is in danger in depth.

I think this is the point where we won't get enough information from the pictures to move further. However it's worrying that these cracks are not mentioned in the documents, even if they are thought to be safe/too small/irrelevant.

I of course agree on all points above. So there's a document which includes photos for apparent documentation which are totally unsuitable as evidence for or against cracks in the context of the inquiry, but it is perfectly alright with Tepco if the reader will conclude from looking at the photos that there are no cracks there at all. In fact that appears to be the intention of the document. I am not worried about that crack, but I don't like to be bs'ed.