Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[Atomfritz]

Adding to this the (i presume by now ascertained) fact that the level measurement monitors the level in the downcomer, not in the core, and the possibility that at least the upper temperature measurement monitors the temperature of the core vessel close to the feedwater inlet (=area affected by the inflow through feedwater lines), this currently leaves us very little on which to base estimates on the state of the cores. As I see it, it could be that only a little part (if any) of the water injected in the reactor vessel actually ends up cooling the core. ...Is there some way to ascertain that the water injected in the reactor vessel actually reaches the core?

Afaik no.
Imagine of a large crust insulating the circulating hot corium in the lower part of the reactor, letting swim maybe some feet of slowly boiling water until these broken reactor interconnections that cause the water level not rise higher. This makes sure that you won't measure much more than 400 degs even if the lower part of the vessel is already glowing bright, almost white, imminently before rupturing.

Besides the roof frame of #4 was hardly damaged by the explosion (which blew through it); and the crane seems to be a lot heavier than that frame, even heavier and sturdier than the concrete pillars.

Looks to me that it will eventually settle down a bit, ripping pool cracks open, and crushing the brittle Zirconiumoxide rod hulls, making a really big nuclear fart.
I hope this won't happen.

Regarding the 6th photo that shows all the rebar and what appears to be a plug laying just below the number 15 on the time readout.

Castor plug?
Looks too small to me to be a reactor plug. If any, then one of the lower ones.

Hey Anton! I've got it! The FHM broke in two pieces and one of them fell back into the SFP! Amazing!

This is what I also see. Could be like in a Hollywood movie.
This will assure for some dramatic possibilities.

In a russian forum mentioned in some other post here some apparently very knowledgeable people say that even recriticality issues could theoretically not be excluded, considering the changed fuel geometry after having been hammered and compacted by the impact of the FHM.

At the end of the video Professor Kazuhiko Kudo of Kyushu University says he is surprised to see that the fuel handling machine at unit 4 looks intact, while other parts of the building have suffered important damage.

Yes, it's working well. It's redesignated function now seems being a SFP plug-in radiation shield. Amazing!

 

[Jorge Stolfi]

I believe containment pressures, according to what I have heard (not seen printed) may have been as high as 120 psig. Most Mark 1s in the US have a 56 psig Design Pressure.[/I][/B]

The max recorded pressure I have seen for #3's drywell is 637 kPa ~ 6.3 bar, on mar/13 09:10. That was just when the RPV pressure started falling very fast from 7341 kPa to below 500 kPa: http://www.nirs.org/reactorwatch/accidents/conditionoftheplants313317.pdf

The max recorded pressure in #1's drywell was 940 kPa, on mar/11 ~23:30, from this plot: https://www.physicsforums.com/showthread.php?p=3225222&highlight=missing#post3225222

The max recorded pressure in #2's drywell was 750 kPa, just before an "explosion noise" was heard and pressure dropped suddenly to 155 kPa: http://www.nirs.org/reactorwatch/accidents/conditionoftheplants313317.pdf

However, beware that those numbers do not come directly from TEPCO, but from data compilations by other people.

 

[rowmag]

I will stay with my theory:
They move some fuel from SFP to core after cooling faliture[...]

Without electricity?

 

[SayaX]

Some New pictures released today of the reactors (Japanese website) for anyone interested:

http://mainichi.jp/select/wadai/graph/20110415_2/2.html

 

[TCups]

I don't think you can point to a couple of diagrams and conclude they represent "the Mark 1 BWR design". For instance, slide 7 in Lochbaum's powerpoint presentation shows the operating rector buildings 1, 2 and 3 have a diameter. The buildings in question are not round, however. On slide 24 there is a diagram that more closely resembles the ubiquitous GE color marketing drawing of a Mark I secondary containment. It does indeed show a cask storage area with gates, but I submit that that area is within the overall volume of the SFP. I have attached a picture that depicts the arrangement of the refueling floor at Oyster Creek for comparison. The NE corner of the SFP has just such a walled-off compartment for fuel casks. The Oyster Creek floor plan also shows the travel path for casks being transported in and out. Note that the equipment hatch is about 90 feet away from the cask storage area in the SFP, in the SE corner of the building.

If you want to call that a separate pool, fine, but the distinction at Oyster Creek is tenuous at best. I think you are relying too much on a few generic Mark I building drawings floating around the net. The Oyster Creek blueprint fragment is prima facie evidence that the layout of a reactor building can and does differ from the diagrams everyone is using to "prove" their points.
It is not known at all. You have posited electric-powered pneumatic seals for the reactor-cavity/SFP connecting passage, but I don't recall seeing any other documentation that confirms that. Even if there are designs that use such seals, that would not automatically mean that they were used at Fukushima Daiichi. In the other Oyster Creek drawings I have, there is no reference whatsoever to pneumatic seals of any kind.

Thanks, Mice & Men. A thoughtful critique is always helpful

I don't have much of an engineering background - a year of ME/Automotive, and I don't claim to be a structural engineer or nuclear engineer. But I don't think it implies anything on the scale of a bad hallucinogenic trip would be required to imagine a difference, perhaps like the first vs the second variations on a theme of the Mark I design. In fact, if one considers the likelihood that SFP storage space was at a premium at Fukushima, and what the photographic and video evidence since day 1 have shown, I don't think variation 2 is much of a stretch at all.

Maybe that presumes too much, but it seems at least to me to fit the visual evidence and might help explain some of the things I and others seem to be struggling to understand.

As for the seals, I didn't make it up out of thin air. I believe this was discussed in some detail back around post 600 or so. See reference:

http://allthingsnuclear.org/post/3964225685/possible-source-of-leaks-at-spent-fuel-pools-at

And as for a the couple of diagrams, I will claim responsibility for having given the impression that perhaps I had only looked at two diagrams. Instead, I have scoured almost every diagram, photograph, and reference posted here since day one, as well as all the other reasonable sources I could find in the process of coming up with several of my wild conjectures.

Does one of these look like what we have been seeing at Fukushima Unit 3 & 4 to anyone else? I think I commented on the apparent incongruity of the elevator shaft on one of the earlier diagrams. I believe the Fukushima photographs pretty clearly demonstrate the alternate position of the elevator shaft and access tunnels in version 2.

Oyster Creek:

http://i306.photobucket.com/albums/nn270/tcups/Picture1-6.png

Fukushima (?):

http://i306.photobucket.com/albums/nn270/tcups/Picture2-6.png

 

[ceebs]

I googled around a bit and found a few other items of interest regarding the core shroud replacement program at Fukushima Daiichi. My understanding is that the "core shroud" is a cylindrical wrapper that surrounds the fuel core inside the reactor pressure vessel (RPV).

looking further at this I came across this That I haven't noticed here

http://www.nirs.org/factsheets/bwrfact.htm"

The core shroud is a large stainless steel cylinder of circumferentially welded plates surrounding the reactor fuel core. The shroud provides for the core geometry of the fuel bundles. It is integral to providing a refloodable compartment in the event of a loss-of-coolant-accident. Extensive cracking of circumferential welds on the core shroud has been discovered in a growing number of U.S. and foreign BWRs. A lateral shift along circumferential cracks at the welds by as little as 1/8 inch can result in the misalignment of the fuel and the inability to insert the control rods coupled with loss of fuel core cooling capability. This scenario can result in a core melt accident. A German utility operating a GE BWR where extensive core shroud cracking was identified estimated the cost of replacement at $65 million dollars. The Wuergassen reactor, Germany's oldest boiling water reactor, was closed in 1995 after wary German nuclear regulators rejected a plan to repair rather than replace the reactor's cracked core shroud.

 

[AtomicWombat]

The plans for relocating the capital of Japan is an old story. The timeline at http://www.mlit.go.jp/kokudokeikaku/iten/English/background/index.html starts in the 1950s, but in old times, emperors changed the location of their capital quite often : http://en.wikipedia.org/wiki/Capital_of_Japan

It's a very sensible idea, but now is NOT the time to rush it.

 

[AtomicWombat]

What is the chimney height and reactor height? We can estimate velocity of rising air there, in reactor 3 explosion video. Hell, we can probably estimate blast energy in kt.

I did this before using 2 methods. I think the most convincing is timing how long the heavy junk takes from the explosion until it returns to roof level again - it's 14-15 seconds. Half this 7-7.5 sec and then use Newton's Laws distance = 0.5*g*t^2 gives around 245-280 metres from memory.

 

[rowmag]

Re: moving the capital:

It's a very sensible idea, but now is NOT the time to rush it.

This hasn't been discussed in the Japanese press at all. If anyone had brought it up, their political opponents would be gleefully roasting them over the fire with it (this is already happening with other disaster-related statements), so I doubt it is being discussed. My vote is against ITAR-TASS getting the big scoop ahead of any other news agency in the world.

 

[shogun338]

The US Department of Energy facility storing melted fuel from the Three Mile Island nuclear plant has not done enough to address crumbling concrete modules encasing the radioactive material, the US Nuclear Regulatory Commission said in a letter made public Friday.

The DOE facility at the Idaho National Laboratory holds the damaged fuel from unit 2 of the Three Mile Island Plant, which, in 1979, suffered a partial meltdown of the core, leading to the US' worst nuclear accident. http://www.platts.com/RSSFeedDetailedNews/RSSFeed/ElectricPower/6002873

 

[shogun338]

Tokyo - Workers in the damaged Fukushima nuclear plant were attempting to reduce radioactive contamination in waters off the coastal power station, the Jiji Press agency reported Saturday.
Some 300 kilograms of zeolith, a mineral that authorities hope will absorb radioactivity from water being pumped the Fukushima reactors, were deposited into the Pacific Ocean, just outside a pipe leading out of reactor 1.http://www.monstersandcritics.com/news/asiapacific/news/article_1633325.php/Work-underway-to-reduce-radioactivity-off-nuclear-plant

 

[shogun338]

The Case for Moving U.S. Nuclear Fuel to Dry Storage
Nuclear waste pools are packed more densely in the U.S. than those at Fukushima, with no removal plan in sight. The 2003 report said that in the event of coolant loss in a densely packed pool, air cooling would not suffice. Temperatures could rise to 600 °C within an hour, causing the zirconium fuel cladding to rupture, and then increase to 900 °C, whereupon the cladding would burn, resulting in huge quantities of released radioactive material, the report said.

The report proposed immediate reversion to lower-density pool configurations, with more cooled fuel put in dry casks and moved to central sites. In looser-packed pools, the report said, airflow alone could be enough to prevent fire in the event of coolant loss. It said this could be done for no more than $7 billion nationally, which would work out to a wholesale electricity price increase of 0.06 cents per kilowatt-hour generated from the fuel. http://www.technologyreview.com/energy/37388/?p1=A4&a=f

 

[AtomicWombat]

An object located near the "center" of a gas explosion presumably would be squeezed hard but not displaced by the explosion.

The naive impression I get looking at the building is that the main blast was on the level below the top floor.

I'm not sure it makes sense to look for the centre of a gas explosion. A hydrogen detonation in air propogates at nearly 2000 m/s with a peak blast pressure of nearly 16 bar (atmospheres).

http://www.gexcon.com/handbook/GEXHBchap6.htm"

For small objects in the fuel air mix, the detonation wave will race around the object, effectively compressing them by 16 bar. However, 16 bar applied to large external walls (with no balancing pressure) will produce a huge force. If there was a clear passage to lower levels in building 4 it is easy to understand how the blast pressure wave reached there too.

 

[AtomicWombat]

And as for a the couple of diagrams, I will claim responsibility for having given the impression that perhaps I had only looked at two diagrams. Instead, I have scoured almost every diagram, photograph, and reference posted here since day one, as well as all the other reasonable sources I could find in the process of coming up with several of my wild conjectures.

Does one of these look like what we have been seeing at Fukushima Unit 3 & 4 to anyone else? I think I commented on the apparent incongruity of the elevator shaft on one of the earlier diagrams. I believe the Fukushima photographs pretty clearly demonstrate the alternate position of the elevator shaft and access tunnels in version 2.

I think we've collectively got the general floor layout of all 4 buildings about right and TCups has made very important contributions to that.

The attached diagram (originally from TCups) appears to be the essential layout of the 4 buildings. Small details, such as how the cask pool corresponds to the rest of the SFP are not yet clear.

 

[AtomicWombat]

I'm trying to analyze more in detail this video to get some information about what flew in the sky ... mainly on its mass. Maybe someone can help me too.
http://energheia.bambooz.info/index.php?option=com_content&view=article&id=170%3Areactor-3-explosion-enhanced-view&catid=60%3Avideo&Itemid=85&lang=it

Some notes:
Take a look on the right side of the reactor 3 and follow the hard material falling down near the tower

1) at the time 0:16 there is an explosion of flammable material that expands almost sideways
2) immediately something shoot oneway directed upward the material as a recoil of the weapon (very strange, like a cannonball!)
3) about the time 0:21 comes to its maximum height
4) at the time 0:32 comes around on the ground near the tower under the law of gravitation http://en.wikipedia.org/wiki/Equations_for_a_falling_body

You state that the time to max elvation is 5 sec, and the time to fall is an additional 11 sec (meaning high drag force). This implies that the terminal (falling) velocity is low. Could you do a frame by frame analysis the determine the maximum elevation, the final velocity before it hits the ground, and the approximate dimensions of the object?
The drag force for an object in air is (for turbulent drag)
F= \frac{1 }{2 } \rho AC_dv^2

The terminal (falling) velocity is given by

\frac{1 }{2 } \rho AC_dv^2=mg

where ρ is the density of air, A is the cross-sectional area, C_d is the drag coefficient, v is the velocity, and mg is the gravitational force.

Here is an example. A golf ball has a terminal falling velocity of 36 meters per second. A golf ball shot straight upward at 100 meters per second will hit the ground in 10.9 seconds, with a final velocity of only 34 meters per second.

Bob S

Some time ago (http://74.86.200.109/showpost.php?p=3222881&postcount=2324") I had a look at this and concluded that:

"As to the height of the blast. I timed how long it took from the initial explosion for heavy debris that fell to the left to hit the ground. It is 14-15 seconds. It reached maximum height in about half this time - there is no evidence of a "rocket effect". Using Newton's Laws of Motion this gives an estimated height of 0.5*g*t^2, where t is half the total time of flight. This gives 5*(7)^2 = 245 metres or 5*(7.5)^2 ~ 280 metres. The building height (50-60 metres) can be added if you like. So I'd say the heavy debris reached a height of about 250 metres above the roof of the building, or about 300 metres total.

The "launch velocity" was about 70-75 m/s or about 250-270 km/h, so air resistance can be neglected for large dense objects.

See here for a clearer video:
http://www.youtube.com/watch?v=haUawwm7l4k"

 

[|Fred]

I have a full picture of unit 4 north wall if it has not been posted yet , rather low quality , but clear enough to see that the east part is almost immaculate

 

[Dmytry]

the velocity estimate from falling debris - i would rather check through height of chimney to know for sure the objects are not reaching terminal velocity, or are not carried up in the plume. Shape matters and there's a lot of panels that are big but thin. Plus it *looks* like they reach terminal velocity as they fall.
I want to make estimate that can't be 'debunked'.
I was unable to find chimney height. Most stupidly, when I google for fukushima chimney height, i get this thread as top result.

 

[Borek]

I'm not sure it makes sense to look for the centre of a gas explosion.

I think it is not a thing to be ignored. I recall a story of gas explosion that happened in a power station somewhere in Poland. Welder standing close to the center of the large workshop used lighter to ignite acetylene torch, that started the explosion. Ironically, he got some burns but survived, while people other workers died from mechanical trauma - they were smashed on the walls by the blast.

Edit: obviously it will be different for deflagration vs detonation, but at this stage I doubt we can tell which one occurred.

Interestingly, I found this: http://www.gexcon.com/handbook/GEXHBchap5.htm#sect5_7 - note, how the effect of deflagration depends on the placement of obstacles. That can (doesn't have to) explain why parts of the upper wall were not blown out - some arrangement of internal objects could slow down the explosion in this particular direction.

I must admit at this moment it is rather anecdotal evidence, I can't give any details. I have heard the story back in seventies, probably from my Mom, she was an Electrical Engineer with PhD.

 

[Borek]

Shape matters and there's a lot of panels that are big but thin.

Plus they rotate, so their cross sections change. I have a gut feeling that possible guesstimates of the mass will differ by orders of magnitude depending on assumptions, making them virtually useless.

 

[AtomicWombat]

the velocity estimate from falling debris - i would rather check through height of chimney to know for sure the objects are not reaching terminal velocity, or are not carried up in the plume. Shape matters and there's a lot of panels that are big but thin. Plus it *looks* like they reach terminal velocity as they fall.
I want to make estimate that can't be 'debunked'.
I was unable to find chimney height. Most stupidly, when I google for fukushima chimney height, i get this thread as top result.

I couldn't find it either. Try starting with the building heights. From the #1 blueprint ground level is OP. 10000 and the roof is OP. 54750 giving about 45 metres.

I measured the height of building 2 in pixels (252) on the SW corner and did the same for the nearest stack (682) - using pythagoras theorem. I could not get a clear line of sight on building 1. So the stack is 2.70 times the building height. This is about 120 metres, assuming a 45 metre height, or 135 metres if you assume building 2 is 5 metres taller than 1 (they seem almost the same).

So start with a stack height of 120 metres. Now estimate the height that the heavy debris reaches in the explosion. This is hard because you can't see ground level, but to my eye it's at most 3 times the height of the stack or around 360 metres.

My two estimates are in rough agreement. I earlier estimated 245 to 280 m plus the building height, giving 290 - 325 metres.

http://www.youtube.com/watch?v=haUawwm7l4k"

 

[Dmytry]

Plus they rotate, so their cross sections change. I have a gut feeling that possible guesstimates of the mass will differ by orders of magnitude depending on assumptions, making them virtually useless.

Yep. I'm very surprised though that there was no word from explosion experts about the video. No estimates of energy, in traditional TNT equivalent.
I'm still looking for chimney height as quoted from official source. It seems clear to me that the explosion in #3 could not possibly have been a hydrogen explosion but I would love to have data to conclusively show it in the way that can't be easily denied.
I'm going to also base height on photo for now and figure out the air movements for the observed plume velocity (not the debris). I did some numerical fluid simulations in the past, this is going to take a while. But overall - this stuff is rising very very fast, I'm sure it is steam vented out of reactor, not steam from hydrogen combustion.

 

[Dmytry]

I couldn't find it either. Try starting with the building heights. From the #1 blueprint ground level is OP. 10000 and the roof is OP. 54750 giving about 45 metres.

I measured the height of building 2 in pixels (252) on the SW corner and did the same for the nearest stack (682) - using pythagoras theorem. I could not get a clear line of sight on building 1. So the stack is 2.70 times the building height. This is about 120 metres, assuming a 45 metre height, or 135 metres if you assume building 2 is 5 metres taller than 1 (they seem almost the same).

So start with a stack height of 120 metres. Now estimate the height that the heavy debris reaches in the explosion. This is hard because you can't see ground level, but to my eye it's at most 3 times the height of the stack or around 360 metres.

My two estimates are in rough agreement. I earlier estimated 245 to 280 m plus the building height, giving 290 - 325 metres.

http://www.youtube.com/watch?v=haUawwm7l4k"

hmm i got about 115 meters with similar calculations so that'd be it... now onto the cloud's velocity estimation, and cloud's temperature estimation (for it to rise this fast), and the thermal energy... going to take a while. And all that work to show something bloody obvious, that you need lot of thermal energy to make mushroom cloud, to provide scientific substitute for common sense of 'omfg mushroom cloud, really bad'. It would of been so much easier for military which probably got premade tables for this sort of calculation to estimate yield.
edit: going to take a while. I'd rather hope someone here can find how military would estimate energy given mushroom cloud width and rise speed, using experimental data. That'd give more confidence.

 

[AtomicWombat]

I think it is not a thing to be ignored. I recall a story of gas explosion that happened in a power station somewhere in Poland. Welder standing close to the center of the large workshop used lighter to ignite acetylene torch, that started the explosion. Ironically, he got some burns but survived, while people other workers died from mechanical trauma - they were smashed on the walls by the blast.

Which ironically proves my point about not looking for the centre based on the most damage.

Plus they rotate, so their cross sections change. I have a gut feeling that possible guesstimates of the mass will differ by orders of magnitude depending on assumptions, making them virtually useless.

I agree Borek. It looks powerful and "heavy" objects are thrown ~300 metres into the air. But beyond this too many assumptions must be made. (I assumed earlier - for the sake of argument - it was the concrete shield plug, but there is no real evidence of this.)

An interesting starting point might be:
http://en.wikipedia.org/wiki/TNT_equivalent"

 

[Dmytry]

Which ironically proves my point about not looking for the centre based on the most damage.
I agree Borek. It looks powerful and "heavy" objects are thrown ~300 metres into the air. But beyond this too many assumptions must be made. (I assumed earlier - for the sake of argument - it was the concrete shield plug, but there is no real evidence of this.)

An interesting starting point might be:
http://en.wikipedia.org/wiki/TNT_equivalent"

Well that is all true, but it'd be strange for most damage to be located on bottom floor for a 'hydrogen produced and accumulated on top' scenario. Not a single other reactor building had wall panels blown off in the bottom floor. I don't believe that entire building worth of combustible hydrogen concentration had exploded. It's one thing for cloud of gas to produce most damage on it's boundary, it's entirely another thing for hydrogen-air mix below the roof to blow off first floor's panels but not top floor's panels, and for reactor building 4 to have less top floor damage but more bottom floor damage than any other reactor building. You can't just shrug this evidence off with 'explosions are complicated'.

 

[liamdavis]

The naive impression I get looking at the building is that the main blast was on the level below the top floor. Could something else have blown up besides hydrogen? Are there any gas or fuel tanks on the 4th floor? Going back to the original (day of blast) speculation of lubricating oil fire, is lubricating oil explosive? (Maybe if it gets aerosolized for some reason?)

Seems hard to believe anything explosive would be present in a reactor building on purpose. Though, since the reactor was undergoing core shroud replacement, which apparently involves welding (according to the link given by MiceAndMen), might oxy-acetylene welding equipment have been temporarily located there?

Speaking about Unit 4, I have posted this position as well. Someone (I apologize, I do not remember who) answered my question about the weight of acetylene. Approximately the same as air, so it would not rise. The more I consider it I would be very surprised if there were not oxy-acetylene equipment present. Forty year old equipment, installed at the seashore, with pools of hot water continually present inside and down for maintenance would be cause to bring on site as many bottles as the contractor/maintenance team thought they would need.

An additional thought is that acetylene is unstable above 8-14psi and so is dissolved into a tank filled with acetone. Tanks are secured (chained) upright but after five minutes of shaking in a 7M (at the plant) earthquake nothing of their condition can be assumed. Acetone vapors could also be present. Once again I am at the mercy of someone more knowledgeable about the specific gravity of acetone vapors.

Add (and stir) the variables of hot water in the top of the building, 0 degree C temps outside, no power/HVAC, and unknown leakage of air into the post-quake building. Apply that to acetylene and acetone vapors and take a wild guess.

 

[Dmytry]

Seems scientifically plausible to hazard a guess they have been breaking a couple dozen regulations at any time, and more during maintenance. Nuclear safety standards are very strict, to the point that i'd think 999 times out of 1000 violating them won't make anything bad happen but would save the money.
I think that could explain various strange aspects of the information availability & disaster management.
However - why would acetylene leave the bottles? And explode after those SFP issues? Why wouldn't they try to do something about it - carry the bottles out - if anything, to cover up the violation? edit: also, acetylene and other hydrocarbons leave soot.

 

[TCups]

I'm trying to analyze more in detail this video to get some information about what flew in the sky ... mainly on its mass. Maybe someone can help me too.
http://energheia.bambooz.info/index.php?option=com_content&view=article&id=170%3Areactor-3-explosion-enhanced-view&catid=60%3Avideo&Itemid=85&lang=it
[/url]

@K:
I have looked at the videos until my eyes are crossed. Don't know how much of the earlier threads you have read in depth. When looking at the viedo, keep some things in mind.

1) as has been pointed out, video compression used for internet display generaly uses compression algorithms that reduce resolution and can sharpen or blur the edges of objects, especially moving objects -- there are compression artifacts in even the best video available of the explosion. Perhaps (but I don't know for sure) the grayscale video is somewhat less prone to artifactual distortion.

2) sunlight and shadow cause an interesting interplay in the video, particularly with regard to the smoke plume and what appears to be in the plume. For example, watch what happens to the brightness and detail of the tower just north of the plume and imagine the same effect occurring with the falling debris in and to the north of the vertical plume. To me, it seems a lot of "things" seem to appear and disappear in that plume. Some of them I believe to be shadows. And all of them are affected by #1 above.

3) Velocities of the visible falling "objects" (which could be anything from sheets of insulation material, to sheet metal, to metal beams to concrete plugs), whatever they are, vary pretty significantly, and their acceleration and velocities no doubt varied on the way up, too.

So if it's hard to identify what is what on the ground and in the buildings on the still photos and videos available, then how much harder is it to be sure what is going up and coming down in that column of smoke?

Ultimately, what appears to be seen on the ground (and in the pools) is much more significant and reliable than what appears to be seen in the column of smoke, IMO.

 

[liamdavis]

Seems scientifically plausible to hazard a guess they have been breaking a couple dozen regulations at any time, and more during maintenance. Nuclear safety standards are very strict, to the point that i'd think 999 times out of 1000 violating them won't make anything bad happen but would save the money.
I think that could explain various strange aspects of the information availability & disaster management.
However - why would acetylene leave the bottles? And explode after those SFP issues? Why wouldn't they try to do something about it - carry the bottles out - if anything, to cover up the violation? edit: also, acetylene and other hydrocarbons leave soot.

why would acetylene leave the bottles?

Bottles left on when the earthquake hit, toppled or damaged by falling material.

Why wouldn't they try to do something about it - carry the bottles out

Within eight hours of total power loss things were going very bad. People had been injured and some (two at Daiichi) were unaccounted for. I do not know if protocol required the maintenance personal or contractor to leave Unit 4 until structural safety was ascertained. And there was the shock of dealing with earthquake, tsunami and power outage.

 

[Dmytry]

Bottles left on when the earthquake hit, toppled or damaged by falling material.

Then explode, let's see, 4 days after, all while there were fires that were extinguished by firefighters. (edit: or that's what i remember from the news of the time)
Does not compute.

Within eight hours of total power loss things were going very bad. People had been injured and some (two at Daiichi) were unaccounted for. I do not know if protocol required the maintenance personal or contractor to leave Unit 4 until structural safety was ascertained. And there was the shock of dealing with earthquake, tsunami and power outage.

a curious mix of diligent following of the protocol and violation of the rules. I'd expect that if they're violating the rules, the first thing they would do, they'd attend to covering up ongoing violations.

 

[liamdavis]

Originally Posted by liamdavis
Bottles left on when the earthquake hit, toppled or damaged by falling material.

Then explode, let's see, 4 days after, all while there were fires that were extinguished by firefighters.
Does not compute.

The quake was not a single event.

http://www.japanquakemap.com/

As of today 1015 aftershocks since 3-11-11. And there was debris falling from other explosions. Damage to tanks could have occurred at many times and could have originated from many sources. I am not meaning to be argumentative. It is just that the number of variables thrown into this event between the initial quake and the subsequent explosions make reconstruction of events worthy of a 3000+ post thread... oh, wait!
liam