Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[rowmag]

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.

The fires came after the explosion (or more precisely, were first observed after the explosion), and went out by themselves (possibly after one day).

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.

No, the first thing they would do, in a dazed state, is try to remember what the earthquake drill is -- which probably involves gathering at some outdoor location for a count of hands. At least that was how it was where I was when the quake hit. Events from there (incoming tsunami) would have quickly taken priority in driving their actions. I would bet that if there were any rules violations going on before the quake, nobody remembered about that until much later.

 

[rowmag]

acetylene and other hydrocarbons leave soot.

The vomitus coming out of the hole in the north wall does look pretty blackened...

 

[triumph61]

New Fotos

http://cryptome.org/eyeball/daiichi-npp9/daiichi-photos9.htm

 

[shogun338]

Zeolites have uses in advanced reprocessing methods, where their micro-porous ability to capture some ions while allowing others to pass freely allow many fission products to be efficiently removed from nuclear waste and permanently trapped. --Shooting location: the south side of the screen of Unit 3 of the
Fukushima Daiichi Nuclear Power Station -
-From 2:30 pm to 3:45 pm on April 15th, TEPCO installed 3 sandbags containing
zeolite (as an absorbent material) between the screen pump rooms of the
Unit 3 and Unit 4.

 

[shogun338]

In this image taken by T-Hawk drone aircraft, Tokyo Electric Power (TEPCO) Co.'s crippled Fukushima Daiichi Nuclear Power Plant No.1 reactor building's rooftop is seen in Fukushima, northern Japan April 15, 2011 . We have found one thing out for sure . That the T-Hawk drone is not worth the money that has been spent on it . I can't believe how bad the pictures and videos taken with it are .

 

[Borek]

'hydrogen produced and accumulated on top' scenario.

I wonder where this scenario came from. From what I remember separation of gases is negligible. What may happen is that gases don't necessarily mix fast, so they can flow - similarly to what liquids do - up or down, but once mixed they remain mixed.

 

[Dmytry]

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

Well the point is, it's just unlikely... you need tanks (plural) to be undamaged by original quake, then you need tanks to be damaged by much weaker aftershock, and the damage itself must not create a spark, nor should be it like regulator knocked off (with the tank taking off like a missile), etc. It's not that it is impossible, it's that it is too specific for the data we got.
Some unidentified **** left over from maintenance, exploding, that is plausible. Who knows. They may have been doing some weird things to the reactor pressure vessel to cover up some defect. http://www.bloomberg.com/news/2011-03-23/fukushima-engineer-says-he-covered-up-flaw-at-shut-reactor.html" . They may have had some unofficial fuel transfer in progress (see the cask vehicle on photos). It seems very plausible that various minor violations would be commonplace, given very interesting accidents like criticality at Tokaimura, accidents that would just be too unlikely without background of violations that don't result in any accident. Suppose they had some fuel in a cask, and it, left to itself, overheated.

 

[Borek]

We have found one thing out for sure . That the T-Hawk drone is not worth the money that has been spent on it . I can't believe how bad the pictures and videos taken with it are .

Assuming video that was published is really the best they have. Could be they don't want to reveal the high quality footage - for number of reasons.

 

[TedNugget]

@K:
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.

TCups:
Looking over the enhanced video there appears to be two distinct 'colors' to the plume that are not entirely explained by shadow. On the left a darker substance, on the right and eventually capping the column is a lighter gray. However, the darker crosses over at least partially eliminating shadow as an explanation for its color.
This two tone column could be the product of; different materials from the same blast or two different explosions.
My apologies if this has been discussed before.

Although I doubt that the time frames would fit there could be an explosion above the shield plug that was self-venting plausibly, (see post 3852), that forced the cookies back down re-establishing a pressure build-up in the containment area and then it blew the cookies off.

Maybe I've developed Fukushima Video Fatigue Syndrome, (FVFS), but the column appears to advance vertically in spurts.

Also of interest is when comparing 3 to the reactor building 1 explosion there doesn't appear to be a pronounced blast wave in 3 but there is a fireball.
This could be simply facets of what each video did or didn't capture.

 

[Dmytry]

Also of interest is when comparing 3 to the reactor building 1 explosion there doesn't appear to be a pronounced blast wave in 3 but there is a fireball.

I noticed that right away. Not only lack of the blast, but also dirt flying sideways quick in #1
And all around #3 looking much slower.
To me it looks like a best example of difference between hydrogen+air explosion vs venting of huge volume of hydrogen and steam. I did CG fluid work, its actually sort of my area of expertise. Reactor stuff, they report pressure not to be zero, i dunno, maybe the lid can be lifted off and then come back down, or maybe gauges failed.

 

[TCups]

I noticed that right away. Not only lack of the blast, but also dirt flying sideways quick in #1
And all around #3 looking much slower.
To me it looks like a best example of difference between hydrogen+air explosion vs venting of huge volume of hydrogen and steam. I did CG fluid work, its actually sort of my area of expertise. Reactor stuff, they report pressure not to be zero, i dunno, maybe the lid can be lifted off and then come back down, or maybe gauges failed.

Take care in analyzing the ground wave blast -- especially any that appears to be moving slowly. Remember, one fundamental difference between the ground level images at Bldg 1 and 3 -- shadow from the plume.

Also, it gives pause to consider any difference that might be due to the giant vertical plume and updraft over Bldg 3 vs Bldg 1 at the time the lower Bldg 3 exploded, if the premise of a three-phase explosive event is correct -- 1) blast from primary containment, out the chute or under the plug, 2) steam blast from the SFP3 with vertical plume, and, last, hydrogen explosion of the lower building (after the vertical plume is rising).

Addendum: and perhaps most importantly, all of the explosion at Unit 1 originated from the upper level only, and that superstructure was steel beam and sheet metal, not reinforced concrete. Also, a bunch of the "new batch" of images are concentrating on the northeast corner of Bldg 4. I wonder why . . .

http://cryptome.org/eyeball/daiichi-npp9/daiichi-photos9.htm

And pict32 is a very interesting photo of FHM 4. The FHM has been "de-masted". Perhaps pretty strong evidence something violent happened within the confines of the SFP?

Pict25, Bldg 3 looks pretty similar to the elevator shaft, cask transfer pool, SFP layout suggested earlier. Steam still venting from the general area of the fuel transfer chute?

 

[GJBRKS]

In this image taken by T-Hawk drone aircraft, Tokyo Electric Power (TEPCO) Co.'s crippled Fukushima Daiichi Nuclear Power Plant No.1 reactor building's rooftop is seen in Fukushima, northern Japan April 15, 2011 . We have found one thing out for sure . That the T-Hawk drone is not worth the money that has been spent on it . I can't believe how bad the pictures and videos taken with it are .

Indeed , they have much better helicopter footage , like :



or



I do hope it is not a disinformation tactic ,

by suggesting that they don't have good quality info to be forthcoming enough

 

[Dmytry]

i don't find it at all hard to believe that t-hawk is a lot worse than hexacopter:

Hexacopter uses state of the art cheap camera from this year. T-hawk uses state of the art certified ultra expensive milspec camera, which is an overpriced version of a cheap camera from several years ago when they started the project. Military drones been consistently years behind hobbyist drones on anything but the cost - hobbyists can't afford big aircraft jet engines.
edit:
I do not think it's even radiation hardened. There's not supposed to be any particularly high dose rates, it's not chernobyl - and in chernobyl, regular cameras worked fine. This thing doesn't fly inside a reactor or anything.
Besides, they never reported trying anything non-radiation-hardened and it failing, so it is really nonscientific to just assume that non-radiation-hardened would be unsuitable.

 

[I_P]

Indeed , they have much better helicopter footage , like :



or



I do hope it is not a disinformation tactic ,

by suggesting that they don't have good quality info to be forthcoming enough

I wonder if the image quality has to do with radiation-hardened camera. Maybe there is some difficulty in getting good images because of this. Seems a bit hard to believe, but (like with the robots - lack of) perhaps there just hasn't been the incentive to develop appropriate equipment for this task and off-the-shelf stuff is not particularly suitable given the requirements.

 

[TedNugget]

To me it looks like a best example of difference between hydrogen+air explosion vs venting of huge volume of hydrogen and steam. I did CG fluid work, its actually sort of my area of expertise. Reactor stuff, they report pressure not to be zero, i dunno, maybe the lid can be lifted off and then come back down, or maybe gauges failed.

In reverse order:
We can see the 'shield plugs - cookies' off the containment in #3. One of the explosions can be just from the containment and not from the reactor. If, IF there still is reactor pressure that would strongly tend to indicate no explosion in the reactor. Just venting from under great pressure.

My sense as a fire fighter is that there is far more energy released in the Reactor 3 building than from #1. #3 took out all walls and roof.
Now this could be just a component of the size of the buildings or different construction methods later on.
Or it could be different explosive materials or the amount of in a larger space ...

 

[Dmytry]

In reverse order:
We can see the 'shield plugs - cookies' off the containment in #3. One of the explosions can be just from the containment and not from the reactor. If, IF there still is reactor pressure that would strongly tend to indicate no explosion in the reactor. Just venting from under great pressure.

My sense as a fire fighter is that there is far more energy released in the Reactor 3 building than from #1. #3 took out all walls and roof.
Now this could be just a component of the size of the buildings or different construction methods later on.
Or it could be different explosive materials ...

Well, in special effects, the #1 would of required a dynamite stick, movies wouldn't even do that, too dangerous. #3, a very small charge inside condom with fuel. In CG, special effects, the first, you just instantly make a lot of air hot, it expands and cools, big cloud, doesn't rise. The second, you vent in giant amount of steam, or approximation thereof (magical air that does not cool down) and you get beautiful mushroom cloud. You can also color some of it burning. But no actual chemical explosion, just a burn. Movies barely ever do explosions like #1 . We really brainwashed everyone about explosions, haha. An explosion in movie is not even an explosion very much, just big fireball. It's also easier to do in CG.

 

[Atomfritz]

My sense as a fire fighter is that there is far more energy released in the Reactor 3 building than from #1. #3 took out all walls and roof.
Now this could be just a component of the size of the buildings or different construction methods later on.
Or it could be different explosive materials or the amount of in a larger space ...

it's because of different material.
Unit 1 has been built without reinforced concrete in the top part, as you can verify in the pictures.
So far less energy got absorbed by the walls, they just popped out and pulverized, leaving the steel girderwork almost undamaged.

 

[Dmytry]

it's because of different material.
Unit 1 has been built without reinforced concrete in the top part, as you can verify in the pictures.
So far less energy got absorbed by the walls, they just popped out and pulverized, leaving the steel girderwork almost undamaged.

look at the videos again, really. The #3 explosion was reported as much more loud from the distance. The #3 explosion had immense volume of air rising at very high velocity. Try explain that with the building material differences.

 

[MadderDoc]

I've stuck together the pieces of the roof structure of unit 3, by locating the single parts, then putting images of those in a 6 by 4 matrix, in the positions they were in before the hydrogen, and the following steam explosion. The result of my effort is this:

There's an html version of the same thing with the images in the original resolution, at
http://www.gyldengrisgaard.dk/fuku_docs/roof3.html

 

[PietKuip]

We can see the 'shield plugs - cookies' off the containment in #3. One of the explosions can be just from the containment and not from the reactor. If, IF there still is reactor pressure that would strongly tend to indicate no explosion in the reactor. Just venting from under great pressure.

In http://www.flickr.com/photos/26255918@N08/sets/72157626384577079/detail/ , I collected some of the thermal images of Unit 3 that the Japanese military has been publishing.

The Spent Fuel Pool is consistently at around 60 C. That would be a minimum temperature. If the temperature of the water is higher, there will be condensed steam obstructing the view of the water surface.

There are variations in the temperature of the containment, but that is due to different degrees of blurring. The chopper takes these images from 3000 ft high. The view of the containment is just a few pixels. There will also be cooler debris in the way.

 

[Bob S]

Energy and pressure in stoichiometric hydrogen-air mixture explosion

Heat of reaction - 3.3 x 10⁶ joules per cubic meter
Pressure - 8.15 bar (abs)
laminar flame speed - 28 m/s

For an empty building 50 m on a side x 50 m high

Total energy = 4 x 10¹¹ joules ≡ 95 tonnes of TNT (4.18 MJ per kg)

See http://www.gexcon.com/handbook/GEXHBchap4.htm

Bob S

 

[TedNugget]

Well, in special effects, the #1 would of required a dynamite stick, movies wouldn't even do that, too dangerous. #3, a very small charge inside condom with fuel. In CG, special effects, the first, you just instantly make a lot of air hot, it expands and cools, big cloud, doesn't rise. The second, you vent in giant amount of steam, or approximation thereof (magical air that does not cool down) and you get beautiful mushroom cloud. You can also color some of it burning. But no actual chemical explosion, just a burn. Movies barely ever do explosions like #1 . We really brainwashed everyone about explosions, haha. An explosion in movie is not even an explosion very much, just big fireball. It's also easier to do in CG.

Another way to tell the power of an explosion is how much was damaged and how far things where thrown.
Its not just that the #1 Reactor didn't have the power to disassemble and discard the roof, its that it didn't have the power to throw much around. Additionally, IMO, much of that darker portion of the #3 plume is from pulverized concrete. Generally with construction methods over time more rebar is the trend. That #3 has all of its concrete walls and ceiling trashed speaks well of that power.

 

[cphoenix]

1mSv/sec is 86 Sv/day. 10 Sv/day is considered absolutely lethal.

You are missing my point. I did not say 1 mSv/sec for 1 day. That would be lethal. But 1 mSv/sec for 1 sec would not be lethal. It would add up to a grand total of 1 mSv.

Likewise, a dose rate that would be dangerous if it lasted for a year might be non-dangerous if it lasted for only a month.

I was responding to a post that calculated backward from the 50 mSv/yr, to compute an acceptable hourly dose rate, and say that people should be told to evacuate rather than be exposed to that dose rate. The poster claimed that Fukushima City residents were at risk. This is a groundless calculation and an incorrect conclusion.

A dose rate that would give you 50 mSv in a year, if it continued at that rate for a year, would be acceptable for one week if it stopped after the one week.

I hope this is clear.

 

[Dmytry]

A dose rate that would give you 50 mSv in a year, if it continued at that rate for a year, would be acceptable for one week if it stopped after the one week.

if you don't ingest or inhale anything radioactive, then yes it would be stopped.
Really, there's 2 entirely different doses. The doses of radiation, which aren't really 'doses' in the chemical sense but just whole body averaging based on linear response model (and weighting factors for different tissues), and a dose of particular radioactive isotope of a particular element, that was inhaled/ingested/whatever and is retained. Fission products tend to be rare in Earth crust, and biologically many of them replace something like e.g. caesium replaces potassium and strontium replaces calcium, and then remain there for a while (in case of strontium, for rest of the life).

 

[Jorge Stolfi]

I've updated my plots of #Fukushima reactor variables to NISA release 97 (16/apr 15:00) :
http://www.ic.unicamp.br/~stolfi/EXPORT/projects/fukushima/plots/cur/Main.html

I have also added plots of core pressure (PC) against drywell pressure (PD), and of suppression torus pressure (PS) agains PD. They allow many interesting inferences to be made, although I cannot quite figure out a single one of them. Perhaps, if the data is not complete garbage, they will allow us to tell the water level in the drywell and/or torus, and/or the size of the vents/leaks between the three compartments, at each epoch since data started to be available.

 

[Dmytry]

Another way to tell the power of an explosion is how much was damaged and how far things where thrown.
Its not just that the #1 Reactor didn't have the power to disassemble and discard the roof, its that it didn't have the power to throw much around. Additionally, IMO, much of that darker portion of the #3 plume is from pulverized concrete. Generally with construction methods over time more rebar is the trend. That #3 has all of its concrete walls and ceiling trashed speaks well of that power.

Yep. And it being slow, it had to be *really* powerful.
Later on I'm going to see if i can find the approximate temperature of rising cloud from it's velocity and size. Assuming it's just rising by buoyancy. I'm very sure that #3 was not a premixed hydrogen+air explosion, but a hot steam+hydrogen venting (explosive venting if you wish), which ignited immediately, and the venting was powerful and fast enough to tear apart entire building, but nowhere near as fast as to create shockwave (confirmed both by lack of visible shockwave which was present in #1 and lack of dust raising by shockwave which was also present in #1).
The image analysis by MadderDoc indicates there was a jet of flame, damaging the steel with intense heat, rather than explosion.

 

[Jorge Stolfi]

I have also added plots of core pressure (PC) against drywell pressure (PD)...

I forgot to explain the color coding of these new plots. The numbers in the plot key are hours since mar/11 00:00. Thus 240-288 would mean a period of 48 hours between mar/21 00:00 and mar/22 24:00. I will try to make that clearer in future releases.

 

[Caniche]

Informative stuff folks ,many thanks .
So as a general overview would it be fair to say we are faced with a scenario of four nuclear reactors undergoing various stages of uncontrolled radioactive emissions that could possibly escalate to runaway critical reactions at any point within the next 10-30 years. RPV's breached;primary containment breached; sfp's look compromised and all you can do is pour on water to dampen the airborne effect but the effluent will just get pumped into the sea.
Any clues on Daini? all in cold shutdown but I notice that due to the cooling interruption the number of reactors at Three mile Island disaster level has jumped from two ,to three today.

 

[cphoenix]

A staggering amount of energy might be stored in pressurized water in spent fuel pools...

(Unless I've made a stupid arithmetic mistake. Someone please check my numbers and arithmetic - is this even plausible?)

Water at the bottom of a pool (40 ft?) is under about 2.2 atm of pressure, so would boil at about 125 C.

The heat capacity of water is 4 J / g C. So 25 C is 100 J/g. I'm assuming this is proportional to depth, so divide by 2 to compute the energy stored in a pool...

Google says that a spent fuel pool has about 1E4 tons of water. That's 1E4 Mg (1E10 g). So if the pool were poorly stirred and heated just right (so it was just below boiling at all depths), then it might have 5E11 J.

That's about 1/10 of a kiloton.

If a pool were in that condition, and then were shaken, the water might flash into steam very quickly. At 2260 J/g, 5E11 J could vaporize about 200 Mg (tons) of water. At ~600 g/m^3 density for steam at 1 bar, that would be about 300,000 cubic meters, or a 70-meter cube.

I'm sure the whole pool was not in this condition. But you could take away a couple of orders of magnitude and still have a very nasty explosion.

 

[Dmytry]

hmm mmm but won't hot water rise up to surface? convection stirring. I don't know how well the rods would prevent convection, especially that they have re-racked it for higher capacity...
edit: entirely unrelated question. Can you superheat egg in microwave oven, if the egg is contaminated with alpha particle emitting isotope? I think, not by much. Someone should do an experiment.