Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[Borek]

Surely it could if those fuel rod are just getting water splashed on them, they'll be corroding like crazy!

Depends on how hot they are (how effective cooling is). From what Astronuc wrote they are designed to be used at temperatures slightly above 300 deg C, and at these temperatures corrosion is very slow.

 

[TCups]

I agree and I think you can be more than 40% confident about that.

A few points:
1) There is clearly water (& debris) in the SFP, indicating no major breach or leak. yes

2) The reactor mouth is completely covered by debris - mostly the overhead crane, which now rests on the operating floor. yes

3) The roof framework that survived the blast seems to have been shielded by the overhead crane - obviously a robust structure capable of lifting about 100 tons. yes

4) Some speculation. The tangled green mess on the north side (see photo) may be the remains of the fuel handling machine. An odd position, but it was an odd day as they clearly were loading spent fuel casks. This would involve the overhead crane and at some point may require moving the fuel handling machine FHM completely out of the way. probably not

Alternate speculation: The FHM blew some distance into the air, then came down on the north end of Bldg 3 doing the damage seen there. Might account for a faulty translation (ie, crane vs FHM -- it was in the original French report, as I recall) about the origin of the damage to the north end of the building.

And here is some really wild and unfounded speculation -- if the fuel transfer process were suspended abruptly when the quake hit, the FHM might still have been connected to a single fuel rod assembly -- remember the infamous rod-like structures on the north end?! -- and would be sitting directly over the SFP. Further, if the rods being transferred were aged and cooled enough for dry cask storage, they would not likely be aglow with heat. They might have been yanked out of the SFP like a fish on a hook, and landed to the north aling with the FHM.

Here is a fascinating video of this procedure with several other fascinating videos in the "suggestions":
http://www.youtube.com/watch?v=rh6FeQWuhCs"

@AWombat -- see above comments added.

@Fred -- 100%! The plug is in place, under the crane.

@ Jens & jlduh -- sorry I responded to the Wombat before I read your posts. I think you were both on to something, too, but perhaps it reinforces my wild speculation above?

 

[artax]

so actual fuel rods are only as thick as a pencil! and they're handled in bundles, 15cm x 15cm x14ft zircalloy casket/box... nothing like what was falling out of building no 3, that's a relief!

 

[TCups]

so actual fuel rods are only as thick as a pencil! and they're handled in bundles, 15cm x 15cm x14ft zircalloy casket/box... nothing like what was falling out of building no 3, that's a relief!

I believe the uranium pellets are about 1 cm diameter and the zirconium steel tube diameter is something more like 15 mm or so from drawings I saw. Sorry, no Immediate reference, but I will check.

http://i306.photobucket.com/albums/nn270/tcups/64f1c409.jpg

http://periodictable.com/Samples/040.14/index.s12.html

http://www.clas.ufl.edu/jur/199911/papers/paper_szollosy.html

Fuel rod diameter is more like 20-25 mm.

 

[AtomicWombat]

To JENSJAKOB:
That's my feeling when i analyse the video. Know from a mechanical standpoint (I'm a mechanical engineer), a high and strong vertical burst (around 500m high) implies that the energy must be somewhat concentrated and directed in this direction more than on the other directions, like in a gun (the bullet is directed by the metal tubing which resists to the radial force), so to me, this vertical burst means that the energy and the point of ignition has to come from deeper in the structure which to some extent has to resist to orient the flux of ejected material to produce that kind of burst. That's why at first I was thinking about the reactor itself being destroyed and ejected through its containment concrete structure (acting as the tubing of the gun). But with all the analysis of the Hi Res picture, it's not FOR SURE from here that the big burst came from. On the other hand the analysis of videos images that I've posted in the post you cited shows that the Burst initiates more on the North side of the N°3 building. To me this would mean that this part ot the building has not been destroyed only laterally and on the top floors but that more SEVERE AND DEEPER damage of the structure can be associated to the fact that we got this big vertical burst.

My other hypothesis would be a secondary (or even tertiary, don't know) explosion from the basement of the reactor building, close to or at the suppression chamber (the Torus), in its NorthWest portion (which is underground). This deep ignition/origin could lead i think to this oriented flux along the containment structure of the pressure vessel, but OUTSIDE OF IT (lateral).

I have been convinced that the strong vertical blast originated in the primary containment for some time, see:
http://74.86.200.109/showthread.php?p=3192958"
Specifically:
"The explosion last Monday was directed strongly vertically suggesting to me it originated from deep within the containment structure. It clearly carried substantial solid material to a height of 400-500 metres. Whilst I can't be sure this may have been due to a melt-down of the fuel rods in reactor 3. They melted through the reactor floor (1500 Celsius) and fell into the flooded "dry-well" below. This triggered a large steam- zirconium-water-hydrogen explosion. I suspected this not only blew the concrete top off the containment, it also blew most of the reactor contents out of the reactor."

I'm no longer so confident that it shows melt-through of the reactor contents, but I can't find any other explanation for such a directional blast.

 

[TCups]

I have been convinced that the strong vertical blast originated in the primary containment for some time, see:
http://74.86.200.109/showthread.php?p=3192958"
Specifically:
"The explosion last Monday was directed strongly vertically suggesting to me it originated from deep within the containment structure. It clearly carried substantial solid material to a height of 400-500 metres. Whilst I can't be sure this may have been due to a melt-down of the fuel rods in reactor 3. They melted through the reactor floor (1500 Celsius) and fell into the flooded "dry-well" below. This triggered a large steam- zirconium-water-hydrogen explosion. I suspected this not only blew the concrete top off the containment, it also blew most of the reactor contents out of the reactor."

I'm no longer so confident that it shows melt-through of the reactor contents, but I can't find any other explanation for such a directional blast.

I can suggest one: superheated steam & gas blow out the fuel transfer chute into the upper SFP (water already hot, or boiling, rapidly vaporizing the water, and resulting in an upward focused blast out of the SFP, launching the FHM skyward, yanking a fuel rod assembly out of the pool as it shoots upward, then crashing on the north end of bldg 3.

I had thought that the original blast at Bldg 3 is on the SOUTH end of the building. The damage on the north end sends stuff crashing downward. If the blast photo is taken from inland, looking eastward, then the blast is to the right, southward. Two towers bracket Bldg 4, on the blast (south) side of Bldg 3. A large hunk of debris comes down on the north side of Bldg 3. But the more I look, I can't make that orientation fit with the towers. Someone help me here.

http://i306.photobucket.com/albums/nn270/tcups/Picture28.png

http://i306.photobucket.com/albums/nn270/tcups/Top.png

Doesn't this view have to be from the west?
http://i306.photobucket.com/albums/nn270/tcups/Picture28.png

 

[rmattila]

with all due respect I think that Gunderson is likely mistaken, Tepco crane felt into the pool , but not that deep. the top of the rod is at least one floor bellow in my opinion.

To me it looks as though the grid Gundersen is referring to as "fuel storage racks" could be rebar net or something similar. It seems to lie on top of the fuel handling bridge, not below it, and even be somewhat twisted on top of the machine at the edge (see attached image).

 

[AtomicWombat]

The plug is in place, under the crane.

I don't think having the crane collapse on the plug after the explosion implies the plug is in place.

 

[jlduh]

TCUPS, the pictures I showed, that i extracted from the video of explosion at No3, and that you talk about at the end of your post, are viewed FROM WEST (inland) towards EAST (SEA).

To me, the note you added in the thumbnail pic is wrong: the Buiding N°1 is not so far to the left, you can see it (no so well because the top has been damaged) a little bit to the left of building 2. Building 3 is the one with the antenna perfectly aligned with the North West edge of the Building 3.

 

[TCups]

I don't think having the crane collapse on the plug after the explosion implies the plug is in place.

Wombat:

Look at the location of the wheels on the side of the rail on the west end of the bldg. That is a reliable reference for where the crane was positioned relative to the structural columns and east-west location of Bldg 3. They are in the middle. The roof fell on top of the crane. The crane is on top of the plug. Now, the plug may be askew -- can't prove it is or is not, but the plug did not, most assuredly blast skyward, straight up, and miss the crane and the center superstructure of the roof.

What think you about the fuel handling machine blasting upward from over the SFP and crashing downward on the north end of Bldg 3?

 

[TCups]

TCUPS, the pictures I showed, that i extracted from the video of explosion at No3, and that you talk about at the end of your post, are viewed FROM WEST (inland) towards EAST (SEA).

jlduh

Please reference the picture post, I want to make sure I am getting it right. My problem is the video pictures I extracted, also viewed from the west, and placing the initial explosion to the south DO NOT coincide with the apparent location of the towers. Trying to resolve.

Again, reference your picture post so I can recheck. Thanks.
Look at the photo attachement to my post 2361 above.

 

[timeasterday]

I wonder how long it will be before they can bring in large equipment to move debris off the tops of the structures? Nobody will really know the full extent of the damage and what caused the #3 explosion until it is uncovered and cameras can get a better look. I am guessing it will be many months before we get a better idea. I can't imagine the scope of this cleanup with every piece of debris probably being contaminated and in need of a secure burial somewhere.

 

[AtomicWombat]

First watch this http://www.bbc.co.uk/news/world-asia-pacific-12931413" released by Tepco, showing close up of the mess in unit 4

Now watch http://vimeo.com/21789121" analysing the Tepco crane head view

Is the spent fuel pool severely damaged and empty or part empty?

with all due respect I think that Gunderson is likely mistaken, Tepco crane felt into the pool , but not that deep. the top of the rod is at least one floor bellow in my opinion.

The HD picture japan-earthquake-2011-3-30-0-50-12 of the full plant view from the south to the nord and previews picture show that we still are on the operating floor. although in normal condition it should be filled .

I'm not sure I'm relieved or disturbed to find the experts having as much difficulty "reading tea leaves" as we are. Does anyone know what is going on?

 

[AtomicWombat]

Wombat:

Look at the location of the wheels on the side of the rail on the west end of the bldg. That is a reliable reference for where the crane was positioned relative to the structural columns and east-west location of Bldg 3. They are in the middle. The roof fell on top of the crane. The crane is on top of the plug. Now, the plug may be askew -- can't prove it is or is not, but the plug did not, most assuredly blast skyward, straight up, and miss the crane and the center superstructure of the roof.

I don't doubt that the crane now rests on the mouth of the reactor, where the plug is or was. The blast almost certainly hit the crane and lifted it off its rails, only for it to crash back down again on the operating floor. Most of the blast would have passed through the gap between the crane beams and around its sides. The crane is more space than beams.

What think you about the fuel handling machine blasting upward from over the SFP and crashing downward on the north end of Bldg 3?

Yes it's possible. I would want to be confident we have identified the fuel handling machine before trying to work out how it got there.

 

[AtomicWombat]

Doesn't this view have to be from the west?
http://i306.photobucket.com/albums/nn270/tcups/Picture28.png

It's from the south west. The cloud is clearly behind the stack, which is to the west side of the buildings.

 

[TCups]

FROM WHERE WAS THE VIDEO OF THE EXPLOSION OF UNIT 3 TAKEN?

I cannot resolve the problem.

Attached are a frame grab from the early part of the video of the explosion of unit 3, a view of the layout of Fukushima Diiachi Units 1-4 (Google Earth), and an edited version of the same image, showing the footprints (1-4) of each reactor building, and the footprints of each of 3 visible towers (A, B, C). Note also, the apparent heights of the "reactor buildings" in the video freeze frame are different.

What angle, taken from the land, would put a tower aligned to the north end of Bldg 3?

What time of day in the northern hemisphere would put the south face of the buildings in shadow?

http://i306.photobucket.com/albums/nn270/tcups/Picture28.png

Here's the video, 11 AM local time, 3/12/2011

http://video.ft.com/v/825918290001/Fukushima-nuclear-plant-explosion

 

[hoyrylollaaja]

FROM WHERE WAS THE VIDEO OF THE EXPLOSION OF UNIT 3 TAKEN?

I cannot resolve the problem.

Attached are a frame grab from the early part of the video of the explosion of unit 3, a view of the layout of Fukushima Diiachi Units 1-4 (Google Earth), and an edited version of the same image, showing the footprints (1-4) of each reactor building, and the footprints of each of 3 visible towers (A, B, C). Note also, the apparent heights of the "reactor buildings" in the video freeze frame are different.

What angle, taken from the land, would put a tower aligned to the north end of Bldg 3?

What time of day in the northern hemisphere would put the south face of the buildings in shadow?

http://i306.photobucket.com/albums/nn270/tcups/Picture28.png

SW,SSW

See tower C cast shadow on RB4 south wall from the sea side, so its most def AM. almost exactly like on your Units1-4.jpg

so that would put the initial RB3 explosion on the EAST, or turbine-building side.

 

[Bodge]

Radical move suggested by Kyodo News:

URGENT: Gov't eyes injecting nitrogen into reactor vessels to prevent blasts

TOKYO, April 1, Kyodo

"The government and Tokyo Electric Power Co. are considering injecting nitrogen into containment vessels of the Fukushima Daiichi nuclear power plant's reactors to prevent hydrogen explosions, government sources said Friday."

http://english.kyodonews.jp/news/2011/04/82625.html

 

[timeasterday]

What time of day in the northern hemisphere would put the south face of the buildings in shadow?

Morning, or very late afternoon to evening. Here's a plot of sunrise/sunset positions for the day #3 exploded.

 

[|Fred]

caption contest :(
Crane Crane, reactor open lid ?

What's the crane on the right (north) doing there ?

 

[hoyrylollaaja]

Looks like very late afternoon to evening. Here's a plot of sunrise/sunset positions for the day #3 exploded.

id still say AM, looking at the casted shadows.

 

[|Fred]

Radical move suggested by Kyodo News:
"The government and Tokyo Electric Power Co. are considering injecting nitrogen into containment vessels of the Fukushima Daiichi nuclear power plant's reactors to prevent hydrogen explosions, government sources said Friday."

The containment vessel are filled with nitrogen in normal time.. providing our understanding of tepco material is correct, rect 1 and 3 were filled with water, there for this concerns only Reactor 2.

 

[hoyrylollaaja]

SW,SSW

See tower C cast shadow on RB4 south wall from the sea side, so its most def AM. almost exactly like on your Units1-4.jpg

so that would put the initial RB3 explosion on the EAST, or turbine-building side.

And this would put the filmer/newscrew on top of some building at Haramachiku.

 

[timeasterday]

id still say AM, looking at the casted shadows.

After looking a bit closer at the explosion photos I think the south side is illuminated, not in shadow. I don't know the exact time of the explosion but I am sure it is documented somewhere.

 

[hoyrylollaaja]

after looking a bit closer at the explosion photos i think the south side is illuminated, not in shadow. I don't know the exact time of the explosion but i am sure it is documented somewhere.

11:08 am

http://news.xinhuanet.com/english2010/world/2011-03/14/c_13777266.htm

 

[rmattila]

URGENT: Gov't eyes injecting nitrogen into reactor vessels to prevent blasts

Makes sense, since hydrogen has been produced, and it has probably no route to escape from the very top of the RPV of the containment. On the other hand, non-deaerated water has been pumped in (first seawater, then freshwater), and calculating from the solubility of gases in the water at different temperatures, this could theoretically result into more than 10 kg of oxygen being released from the water first into the reactor vessel and from there into the containment, eventually diluting the nitrogen atmosphere - if there even is any nitrogen atmosphere left in the containment after the continuous venting during the past three weeks.

 

[jlduh]

Ok, for TCUPS and ALL, the reference post with the frames (which orientation is currently debated) that I captured from the video, including the video link, is #2218:

https://www.physicsforums.com/showpost.php?p=3221329&postcount=2218

For TCUPS: I was saying that to me you misplaced to much to the left the Building N°1 on the Attached Thumbnail Pic that is incuded in your #2361 post:

https://www.physicsforums.com/showpost.php?p=3223194&postcount=2361

 

[mantrogo]

On the subject of the radionuclide analyses. Post above indicated that apparently the reanalysis shows that while some of the numbers are gibberish, TEPCO stands behind the I 131 numbers. If this is the case, and the Cs137 numbers are also correct, an interesting conclusion can be drawn.

If you convert the Bq cm-3 readings into numbers of particles you find that the ratio of Cs137: I 131 is about 12,000 : 1. The fission yield data that I've got from Wikipedia (*shrug* reasonable place to start) suggests that the ratio of Cs137:I 131 yields is about 2.15:1. Given their different half lives and assuming that the activity of a fuel rod drops linearly over time (ok, dubious, but it's probably a fair estimate) then you get this sort of ratio right at the end of the life of the rod.

In other words, these sort of readings are appropriate with spent fuel. Wouldn't be appropriate, even after 2 weeks, with live fuel (assuming that the average age of all the rods is half the rod lifespan).

On a related note found an interesting article in the IEEJ: Apr 2008 ("Impacts on International Energy Market of Unplanned Shutdown of Kashiwazaki-Kariwa", Murukami, Watanabe et al) that looked at the shutdown of TEPCOs Kashiwazaki-Karima nukes following the 2007 Niigata quake. The reactors successfully shut down and remained intact despite floor accelerations much higher than design (3x horizontal in reactor 2). So ... kudos to the engineers.

But...

Water leaks into the sea from the spent fuel pond "TEPCO has explained that water flew out of the spent fuel pool to the operating floor on the quake and leaked to the non-controlled area through the fuel exchanger cable and through the wall separating the radiation controlled area from the non-controlled area"

Plus ca change ...

I 131, 133, Co 60, Cr 51 released into main venting stack. Apparently got there from the condenser as the ventilator didn't shut down properly.

 

[jlduh]

Concerning the orientation of the frames from the video of N°3 explosion:

http://www.netimago.com/image_184705.html

There are THREE stacks ("antennas) in this area, two have on vent and one has multiple vents. the one which has multiple vent is on the very South side of the plant, after No4 building. Then there is one "antenna" in between 1-2, AND 3-4 reactors, on the west side oh them (inland). So based on this fact, the video is showing the 3-4 antenna at the the north west edge of building 3 and is seen from SOUTH/SOUTH WEST TOWARDS NORTH/ NORTH EAST.

Do you agree with that?

EDIT: DAMN TCUPS YOU ARE RIGHT! THE ANTENNA IS NOT AT THE NORTH WEST SIDE OF THE BUILDING No3, IT IS AT THE SOUTH WEST EDGE OF IT! The illuminated white side is the SOUTH side of course, not the west side...

Optical illusion!

That ruins all my explanations so far... but that's not important, we have now materail to reassess everything!

Clever eyes you have TCUPS!

 

[TCups]

THE BLAST AT BLDG 3

OK, this fits. The fuel handling machine went ballistic.

The camera angle for the video is from the south-southwest (green arrow).

The blast is from the southeast corner (over the SFP3)

The large heavy debris in the video does a back flip over the tower, coming down to the left of the tower, and smacking the north west corner of Bldg 3.

I again propose that the heavy debris was the green fuel handling machine, and I cannot dismiss that if it were hooked onto a single spent fuel rod assembly that was in the process of being uploaded for dry cask storage when the quake hit, that the FHM it took one with it on its ballistic trajectory (dark green parabola).

Refute it!

here is the video again

http://video.ft.com/v/825918290001/Fukushima-nuclear-plant-explosion

And here is a shot showing the direction of the wind after the blast, which also fits.

https://www.physicsforums.com/attachment.php?attachmentid=33860&d=1301658258