Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[|Fred]

, I presume that you will not want to park the FHM over the SFP

You could be wrong ;) looking at unit 1 the only thing remaining of the operating floor are the cranes. I ask my self the question If it was not a park default position.. (as it would raise question as what is going on on unit 3

The crane around the FHM is gone or beyond recognition. mind that on unit 4 there was a huge blast just due to the Fuel in the pool, and tha FHM and crane is almost scratch less..
I think the ballistic FHM does not seems that unconceivable .. the FHM on unit 3 is barely recognizable

 

[M. Bachmeier]

Note, that was a Carbon Fuel Burning Boiler. More than likely tubes with hot water on the inside and carbon dust on the outside where the flames of combustion are. When the tube bursts it kicks up a lot of carbon soot (and probably put the fire out).

Oh, by the way. A hot water boiler has the water tubes in a circle around the central heating chamber which is lined with fire brick. The explosion would come from the superheated water, most likely at a weak point outside the core. External pipe, door seal etc. The combustion chamber would likely have little to do with the steam plume.

 

[skodises2]

First post for a new member. Looking at the ruins of unit 3, one thing fascinates me, and I haven't seen anyone else touch upon it. Please forgive me if it has been beaten to death and I've missed it- consider this a preemptive mea culpa.

It seems to me that a lot of discussion has gone into the debris that went straight up, and with good reason- that was downright ugly, and the explosion that propelled all that material was incredibly violent. But to my untrained, layman's eye, there also appears to be a lot of evidence that at some point there were some significant and perhaps somehow focused blast effects directed completely *horizontally* off to the east-southeast. The attached markups show what I mean, with annotations detailing what seems like two possible blast paths/debris trails that happened to intersect the upper edge of the turbine building walls above the roofline. In fact, it appears to me that in the image fuku3_2a.jpg, there is a panel blown in on the turbine hall wall roughly in the path of the northmost area of interest, and one of the ventilation covers has been either forced up or sucked up out of its place as the blast wave and associated debris passed- perhaps at the time of the initial fireball.

The most compelling thing to me is the damage to the turbine hall walls: the decorative caps are gone in these hypothetical paths, and the east wall (furthest from the reactor building) has been peeled off right down to the roof line in two places that seem to line up well beyond what I can make myself believe could be ascribed to randomness.

The image fuku3-3a.jpg (low angle looking back to the west) was the one that initially caught my eye, as the localized damage to the east wall in those two places is pretty clear. Which leads me to wonder what sort of phenomenon might have been responsible for this: these two hypothetical paths seem to converge on the northwest corner of the unit 3 reactor building, more or less, which is certainly the most completely demolished. I wonder if this might be evidence of some very energetic event occurring there, perhaps early in the sequence before the bulk of the energy turned upwards. And why over there? I have a hard time imagining what contributed to the apparent angularity. Why did the blast wave not simply propagate out perfectly parallel to the wall of the reactor building?

In any case, the debris pile at the X in the extreme upper right of fuku3_2a.jpg would seem to me to be a good candidate for something that was expelled almost horizontally during this hypothetical event, clipped both sets of walls on the turbine hall on its way by, and finally came to rest across the access road against the smaller building near the water.

I could be, and very probably am, incredibly wrong here. I have no training in this area, and no reason whatsoever to expect that this will prove to be of any value. But I can't help thinking that those two debris paths, taken together with the wall damage, are inconsistent with being deposited vertically from the debris cloud created by the larger, vertically oriented explosion...

 

[timeasterday]

First post for a new member. ...

Nice first post! You bring up some interesting observations. I hadn't even noticed those debris patterns until you brought them up. Hmmm...more to think about.

 

[|Fred]

Hi
Actually it was one of the first thing that was discussed on the thread when, the hole in the turbine building : could it be the concrete slag of the reactor.. at the time we had really low resolution picture.
Since then we got ok picture and you are right we can pretty much think that all those marks (dont let the perspective deceive you) came from the "windows" of last 2 floors( not sure witch floor) .. windows made of concrete panel.. when the building blowup they were eject in strait horizontal line + parabolic @ gravity

I made an other picture on this https://www.physicsforums.com/showpost.php?p=3223071&postcount=2347
if you look at the original HD picture that I used you'll get a better idea

PS: any how nice observation skodises2, keep them coming !

 

[NUCENG]

Here is a labeled version of my "hallucination". The http://www.spiegel.de/images/image-198534-galleryV9-orwt.jpg" , was posted by AntonL.

1 - fuel rods from one assembly?
2 - wider water tube from center of assembly?
3 - bottom of assembly?
4 - racks from spent-fuel pool?
5 - sleeve of assembly?
6 - sleeve of assembly, burst open, oxidized on outer side?
7 - water in/out pipes from spen-fuel pool?

Item 7 seems to match a model of the SPF shown on NHK. Items 6 of course are more likely to be metal roof panels (but where from?)

OK, time to go to bed...

#7 is ventilation ducting,
#6 may be corrugated steel siding
#5 ?
#4 is part of handrrail extwning to left arounf fuel pool,
#3 ?
#2, #1 Compare diameters with the handrails on the refuel maxhine. Handrails are tyoically about 1.25 inch diameter. Water rods are not found on 8x8 fuel. If it is a fuel rod on 8x8 it is about 0.6 inches diameter. A 10x10 rod is only atout .4 inch diameter. A better guess would be conduit or scaffold piping.

I have been corrected on the number of spacers on fuel bundles. There are 7 or 8 spacers so the maximum LIKELY piece of a fuel or mater rod should be on the order of 20 inches. It is incredible that a large number of full length rods would survive an explosiion which "peels open" a fuel channel.

I have known a couple of photo recon interpreters who told me it is hard not to see things after looking at a photo too long or too hard. I have spent a lot of time in BWR reactorbuildings and I don't recognize very much in the wreckage. We've already heard that there was a body in one photo. Next thing is likely to be somebody spotting bin Laden.

 

[robinson]

Is there any doubt at this point, that the pools are full of debris? And damage to the spent fuel rods is certain?

 

[NUCENG]

Hi
Actually it was one of the first thing that was discussed on the thread when, the hole in the turbine building : could it be the concrete slag of the reactor.. at the time we had really low resolution picture.
Since then we got ok picture and you are right we can pretty much think that all those marks (dont let the perspective deceive you) came from the "windows" of last 2 floors( not sure witch floor) .. windows made of concrete panel.. when the building blowup they were eject in strait horizontal line + parabolic @ gravity

I made an other picture on this https://www.physicsforums.com/showpost.php?p=3223071&postcount=2347
if you look at the original HD picture that I used you'll get a better idea

PS: any how nice observation skodises2, keep them coming !

Sorry, relplied to wrong post.

 

[curious11]

#7 is ventilation ducting,
#6 may be corrugated steel siding
#5 ?
#4 is part of handrrail extwning to left arounf fuel pool,
#3 ?
#2, #1 Compare diameters with the handrails on the refuel maxhine. Handrails are tyoically about 1.25 inch diameter. Water rods are not found on 8x8 fuel. If it is a fuel rod on 8x8 it is about 0.6 inches diameter. A 10x10 rod is only atout .4 inch diameter. A better guess would be conduit or scaffold piping.

I have been corrected on the number of spacers on fuel bundles. There are 7 or 8 spacers so the maximum LIKELY piece of a fuel or mater rod should be on the order of 20 inches. It is incredible that a large number of full length rods would survive an explosiion which "peels open" a fuel channel.

I have known a couple of photo recon interpreters who told me it is hard not to see things after looking at a photo too long or too hard. I have spent a lot of time in BWR reactorbuildings and I don't recognize very much in the wreckage. We've already heard that there was a body in one photo. Next thing is likely to be somebody spotting bin Laden.

Has the strange shiny grey translucent stuff been discussed yet? I can't see how it can be smoke as it's definitely got a reflective property to it.

 

[Jorge Stolfi]

It seems to me that a lot of discussion has gone into the debris that went straight up [...] But to my untrained, layman's eye, there also appears to be a lot of evidence that at some point there were some significant and perhaps somehow focused blast effects directed completely *horizontally* off to the east-southeast.

My reading is that the blast was mostly horizontal. The H2 explosion should push in all directions, but presumably the massive crane and the heavy roof structure anchored on the concrete columns presented more resistance than the thin concrete shell on the walls. To me, the dust and debris in the impressive "mushroom" cloud were mostly carried by the buoyant hot steam (gaseous H2O has half the density of O2,N2) a few seconds after the explosion proper. Howere some debris were thrown up before the mushroom started rising, and then fell through it.

 

[|Fred]

@curious11
Could it be tar ?

 

[DSamsom]

From IAEA's daily briefing:

"On 5th April, measurements were made at 7 locations at distances of 16 to 41 km, South and South West to the Fukushima nuclear power plant. The dose rates ranged from 0.3 to 31 microsievert per hour. At the same locations, results of beta-gamma contamination measurements ranged from 0.01 to 3.2 megabecquerel per square metre."

Interesting, since de data from MEXT in no way show these levels (31 microSievert/h, 3,2 MBq/m2) in south or south westerly direction. Measurements bij MEXT are taken on or close to the 20 km radius-line, so the difference might be explained by the difference between 16 km an 20 km, but that seems unlikely because the distance-dose ratio isn't that steep. Is MEXT selectively choosing its monitoring posts? Or is IAEA?

 

[Jorge Stolfi]

I have known a couple of photo recon interpreters who told me it is hard not to see things after looking at a photo too long or too hard. ... Next thing is likely to be somebody spotting bin Laden.

He he. But that is not reason not to try, is it? We are here mostly to learn, and for that asking stupid questions is essential...

 

[Imipak]

Excellent diagrams.
from this vid the vertical pressure wave does follow the first blast.

The "vertical pressure wave" is just the shock wave making itself visible by condensing water vapour in the air, *not* the blast wave itself. Moon, finger. A "vertically moving" compression wave does not necessarily mean there's no lateral blast wave, or that the vertical component was more powerful than the horizontal.

 

[M. Bachmeier]

Usually, those that I have worked with were U shaped pipes (Circular or U, they allow for expansion and contraction with temperature change. In the video it looked like the explosion came out of the combustion area. Those curved pipes are subject to external (fireside) acidic corrosion and are usually replaced in boilers that have a lot of use. When you get a rupture in a steam boiler operation, it is usually one of the tubes.

Yes and another point I should bring up is some fuels (bunker oil) can interact with (small) water leaks (water boilers) to make highly corrosive acid, which could lead to tube failure and seal failure.

 

[TCups]

Hi
Actually it was one of the first thing that was discussed on the thread when, the hole in the turbine building : could it be the concrete slag of the reactor.. at the time we had really low resolution picture.
Since then we got ok picture and you are right we can pretty much think that all those marks (dont let the perspective deceive you) came from the "windows" of last 2 floors( not sure witch floor) .. windows made of concrete panel.. when the building blowup they were eject in strait horizontal line + parabolic @ gravity

I made an other picture on this https://www.physicsforums.com/showpost.php?p=3223071&postcount=2347
if you look at the original HD picture that I used you'll get a better idea

PS: any how nice observation skodises2, keep them coming !

Uh . . . beg to differ with your flight path analysis.

First, go back and look at the elevation and consider the downward parabolic flight those heavy panels took.

Next, identify where 2 of 4 smacked the nearside back wall of the turbine building, bounced up, then crashed through the top of the building.

Next, identify where 3 more missed the back wall completely, skidded on the more distal aspect of the roof, and crashed through the front facade of the turbine building.

The one central panels were, I suppose somehow protected by the crane and didn't make it as far.

http://i306.photobucket.com/albums/nn270/tcups/Screenshot2011-04-05at44958PM.png

Just for fun, you can check out the two panels that hit the building to the west of Unit 3 as well, and the debris fields those left.

Remember to take into account the differential heights of the buildings when those big old slabs were lobbed outward.

Then tell us if you still think your initial assessment correct.

Addendum:

Sorry, I was speaking from memory. Actually 5 panels impacted the turbine building that I can identify.

http://i306.photobucket.com/albums/nn270/tcups/Screenshot2011-04-05at50011PM.png

 

[Astronuc]

If there were fuel debris, then I would expect to see channels and tie plates, and probably not fuel rods.

The channels are about 5.3 inches (134 mm) across and about 160 inches (~4 m) long.

An 8x8 fuel rod has an outer cladding diameter of 0.484 inch (12.3 mm) and the large central water rod has an outer diameter of about 1.3 inches (33 mm). Older 8x8-2 assemblies had smaller water rods.

 

[TCups]

Were starting with superheated water (like a glass of pure water heated in a microwave). If a (relatively) small leak (re: failure at seal of cap) blew out sideways through the transfer gate, there would be a sudden rapid expansion of volume in the remaining liquid. The pressure would increase so rapidly that any other weak point, including an overstressed torus could give way.

99% steam?

@Bachmeier

Thank you sir. I had forgotten that factor. The water in the pool, before the explosion would be absolutely as pure as possible. Look how still and clear the pools are in all the photos, too. The SFP water certainly could superheat then explode. Ever heat distilled, deionized water in a clean Erlenmeyer flask that you forgot to put a boiling chip in, then dropped one in after it got hot? Don't try it. You will get a first hand demonstration of what might have happened.

 

[M. Bachmeier]

@Bachmeier

Thank you sir. I had forgotten that factor. The water in the pool, before the explosion would be absolutely as pure as possible. Look how still and clear the pools are in all the photos, too. The SFP water certainly could superheat then explode. Ever heat distilled, deionized water in a clean Erlenmeyer flask that you forgot to put a boiling chip in, then dropped one in after it got hot? Don't try it. You will get a first hand demonstration of what might have happened.

Just wonder what would happen if I did that experiment again and dropped a salt tablet into the water to trigger the boiling. Funny reminds me of hot ice. By the way anybody who's done this experiment will tell you the force (rapid expansion) from 8oz. / 250ml of superheated water is unreal and dangerous.

P. S. Just found this, wonder if it has any bearing on the discussion:

http://en.wikipedia.org/wiki/Steam_explosion

 

[|Fred]

Uh . . . beg to differ with your flight path analysis.

wasn't analysis rather a quick and dirty drawing showing that they were more than the 2 panels suggested, and that they flue it rather strait line + gravity. ;)
I'll take your word for the proper flightpath.

ps looking at the video of the u3 explosion , doest anyone feel that there was more than one object of importance falling back ? 2 at least to the left of the picture and possibly one to the right.
Also doing frame by frame I have the optical illusion than just before the orange flash the roof dropped slightly as if it was compressed, does it make any sens explosion wise?
(Any cash course you would recommended to learns the basics of explosions ?)

 

[TCups]

wasn't analysis rather a quick and dirty drawing showing that they were more than the 2 panels suggested, and that they flue it rather strait line + gravity. ;)
I'll take your word for the proper flightpath.

ps looking at the video of the u3 explosion , doest anyone feel that there was more than one object of importance falling back ? 2 at least to the left of the picture and possibly one to the right.
Also doing frame by frame I have the optical illusion than just before the orange flash the roof dropped slightly as if it was compressed, does it make any sens explosion wise?
(Any cash course you would recommended to learns the basics of explosions ?)

Not me -- I am too old to enlist in the military.

I was wondering if there might be two major pieces of the FHM that separated. And we never saw that wench again after the explosion.

 

[|Fred]

If a (relatively) small leak (of hot steam) blew out , there would be a sudden rapid expansion of volume in the remaining liquid

Could you please point at the phenomenon so I could look it up.

 

[razzz]

I can't confirm the sound track to Unit 3 explosion. Count the seconds (2) after the flash to sound and divide by 5, you get less than a mile away or less then a km. Camera is reported to be 30km away.

Best sound for Unit 1 explosion I could find...

"watch?v=h6MaXQwHBqs"[/URL]

I go with M. Bachmeier's scenario so far. Unit 3 looks and acts like a launch pad with ignition, vertical lift and side exhaust. I just wonder what the fuel source was because a large amount of steam (superheated) would have to be under pressure to release like that. Hydrogen would have to be under pressure to lift the working platform and everything on it towards the sky.

Grey slags look like melted lead from batteries in Unit 4.

For a company that spends most of its time obfuscating or saying 'we don't know' there sure is a lot of contamination.

Tell the local natives that irradiation is good for them and will probably prevent the next cold/flu season. I don't who the Russians are trying to fool, they will just condense the wreckage then kick it over the side into the Pacific. Sure you don't want to use a controlled nuke blast and send everything around the globe in the upper atmosphere and into the Pacific, now, instead of this slow bleed? If units 5&6 fail, lookout.

I'm a product of public education so you can discount all I say.

From [PLAIN]http://en.wikipedia.org/wiki/Fukushima_I_nuclear_accidents"

At 11:15 JST on 14 March, the envisaged explosion of the building surrounding reactor 3 of Fukushima 1 occurred, due to the ignition of built up hydrogen gas.[249][250] The Nuclear and Industrial Safety Agency of Japan reported, as with unit 1, the top section of the reactor building was blown apart, but the inner containment vessel was not breached. The explosion was larger than that in unit 1 and felt 40 kilometers away. Pressure readings within the reactor remained steady at around 380 kPa at 11:13 and 360 kPa at 11:55 compared to nominal levels of 400 kPa and a maximum recorded of 840 kPa. Water injection continued. Dose rates of 0.05 mSv/h were recorded in the service hall and of 0.02 mSv/h at the plant entrance.[251] It was reported that day that eleven people were injured in the blast.[252] Six soldiers from the Japanese Central Nuclear Biological Chemical Weapon Defence Unit are reported to have been killed in the explosion.[253]

 

[M. Bachmeier]

Could you please point at the phenomenon so I could look it up.

Sorry, this link added after (because i found it after) might help.

http://en.wikipedia.org/wiki/Steam_explosion

 

[razzz]

Could you please point at the phenomenon so I could look it up.

There was a report where the cap for this particular design fails and vents sideways at a certain pressure and found to be true in real time testing.

Until 4 vessel underwent hardening via reheating and slumped according to the man in charge of the reheating, he falsified the procedure by altering the computer program readouts, with the company's blessing and got a bonus for saving the company money by avoiding trashing the vessel. Employee recently came clean on the events, he was ignored.

 

[TCups]

Sorry, this link added after (because i found it after) might help.

http://en.wikipedia.org/wiki/Steam_explosion

So the superheated water in the SFP3 littorally exploded!

 

[ian_scotland]

This is my first post after following this thread for a few weeks now.
Many thanks to all who have provided such a fascinating insight for me. I am not an academic, but an architect - so please forgive me if I'm not on par with referencing quotes or material or have posted this reply incorrectly. It is also late here and I've had a very hard day looking after my kids!

Uh . . . beg to differ with your flight path analysis.

Next, identify where 2 of 4 smacked the nearside back wall of the turbine building, bounced up, then crashed through the top of the building.

Having watched the video of reactor 3 explosion, it is evident that a lot of material blasted upwards came down in the vicinity of reactor 3. We already have the hypothesis that the FMH went ballistic and arced back to the north end of unit 3. May I suggest that other heavy "stuff" is visibly returning too and it is this that caused the perforations to the roof of turbine buildings 3 and 4.

The parapet wall (the up-stand around the edge of the roof) is invariably of very lightweight construction as it is primarily just to catch rainwater and provide a visual edge to the roof. It is unlikely to have the strength to "bounce" [STRIKE]heavy[/STRIKE] concrete panels upwards.

EDIT upon further thought those reinforced concrete panels are going to spall significantly, and most likely be little more than fist sized bullets. Maybe enough material hanging together with some reinforcement bar to remove parts of the parapet wall but highly unlikely to penetrate the roofs turbine buildings. Such "shrapnel" evidence is visible beyond the turbine buildings too. Example given below (from MECHANICS OF QUASI-BRITTLE MATERIALS, Gianluca Cusatis, Ph.D)

source http://www.cusatis.us/?cat=6

http://www.cusatis.us/wp-content/uploads/2010/01/blast.png

 

[javadave]

what do you experts think of the latest NEI blog re: recriticality of the reactors?

http://neinuclearnotes.blogspot.com/2011/04/recritical-thinking.html

 

[PietKuip]

what do you experts think of the latest NEI blog re: recriticality of the reactors?

http://neinuclearnotes.blogspot.com/2011/04/recritical-thinking.html

That blog entry is correct. See also http://nucleardata.nuclear.lu.se/nucleardata/toi/nuclide.asp?iZA=520429 for data on Te-129m

The incredible thing is that Tepco do not understand their own measurements. See also http://www.nytimes.com/2011/04/06/world/asia/06tepco.html

Such a company should never have been allowed to operate a nuclear reactor.

 

[Emreth]

I seriously doubt that the FHM can go ballistic like that. It's a slim and heavy structure that can not provide enough resistance to the expanding gases which would would just flow around it. It's like putting something inside a cannon which does not fit snugly, not enough momentum will be transferred to the object. I think with the first explosion, which is somewhat directed sideways, the FHM might be hurled against the north destroying that side, depending on the blast location, i assume would be close to SFP. In the top views of reactor 3, i also saw some green areas in the SFP, maybe those are pieces of the FHM as well. The first explosion looks kind of dirty compared to a hydrogen explosion, the fireball is very red/yellow, maybe the mixture was poor in oxygen. The implosion from that seems to trigger the secondary explosion. It might be a steam blast when a low gas density/vacuum formed in there. The explosion seems the pulverize a lot of the concrete stuff, hence the dirty dusty look. I think parts of the ceiling trusses are what are coming down afterward.

 

[Astronuc]

That blog entry is correct. See also http://nucleardata.nuclear.lu.se/nucleardata/toi/nuclide.asp?iZA=520429 for data on Te-129m

The incredible thing is that Tepco do not understand their own measurements. See also http://www.nytimes.com/2011/04/06/world/asia/06tepco.html

Such a company should never have been allowed to operate a nuclear reactor.

So they messed up with Co-56 vs I-134, Cl-38, and Te-129/129m. And TEPCO is not sure about the Te-129

That certainly does raise concern.


I've seen site and utility management replaced over much lesser problems.

 

[tyroman]

@Tcups;

From your post #2936:
https://www.physicsforums.com/showpost.php?p=3230713&postcount=2936
"The reactor vessel is now mostly dry, really, really (red?) hot, and making hydrogen and oxygen."
and
"Gas in the primary containment ignites"

How does hot fuel make Oxygen? And where does the Oxygen needed to ignite Hydrogen in primary containment come from?

Please look again at my Mar25-11, 02:31 PM post #1227 on page 77 of this thread:
https://www.physicsforums.com/showpost.php?p=3209718&postcount=1227

For your theory to be justified, we need to resolve the question of how Oxygen becomes available within primary contaiment in sufficient volume to satisfy Hydrogen's UEL (considering the presence of steam). This issue has STILL hot been addressed.

Tyroman

PS: In that post, where I say;

"When Hydrogen burns (explodes), there is one molecule of Oxygen for each molecule of Hydrogen;"

I obviously meant -
"When Hydrogen burns (explodes), there is one molecule of Oxygen for two molecules of Hydrogen;"

BTW, when I was in Armor, we referred to an armadillo as "A rat with a tanker's MOS."

.

 

[TedNugget]

Ian:

I've got over twice as many posts as you. Ha

"Having watched the video of reactor 3 explosion, it is evident that a lot of material blasted upwards came down in the vicinity of reactor 3. We already have the hypothesis that the FMH went ballistic and arced back to the north end of unit 3. May I suggest that other heavy "stuff" is visibly returning too and it is this that caused the perforations to the roof of turbine buildings 3 and 4."

I agree. That heavy roof came down somewhere and it might have been on the turbine roof.
In some of the photos there appears to be a directionality of debris from the east side of the reactor building. Look that over and see where the smaller puncture hole to the NE looks to be offset from that debris flow.
Looking over the superstructure of Reactor 3 there was a fair bit of steel that left the building. Wonder where that came down?


Maybe someone with double my posts will respond.

 

[tyroman]

As to panel trajectories from Unit 3...

Sketches I made some time ago but didn't post are attached. These were intended as a reply to a much earlier question about the origin of an almost intact panel leaning against the building just East of the turbine building.

The specific panel in question probably was a Southmost-East facing panel from either the top or second row of panels of Unit 3.

BTW - perspective does make it difficult to judge the source...

.

 

[Bob S]

This just in from TEPCO (May be a duplication)

At 5:38 am on April 6th, we observed the stoppage of the water spilling
from the crack on the concrete lateral of the pit. Details of the
situation will be announced after checking the blockage of the water
flows.

We will continue the countermeasure in order to prevent further outflow
of high level radioactive materials to the ocean.

From http://www.tepco.co.jp/en/press/corp-com/release/

Bob S