Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[jensjakob]

FIRST EXPLOSION or FIRST TWO EXPLOSIONS?

a) BIG ORANGE FLASH AT THE LEFT SIDE TOP OF THE REACTOR. This is South side. So it starts with probably an H2 explosion in the top rop, close to SFP.

b) BIG DARK GREY BURST ON THE LEFT SIDE OF THE BUILDING (North)

PERSONAL CONCLUSIONS: to me pictures of the debris correlate with pictures of the explosions (what a scoop hey!). On the south side at the top we see the place of the first flash above the pool, with a big hole and around the metal is heavily bent. On the North west side, this has been the place of the big vertical burst: heavy destruction of the building, with some holes still visible from the bottom. The metal structure of the roof which stays in the middle seems to have been displaced towards the south by the vertical burst. The south side of reactor n°2 has been crippled by the lateral debris projected by the lateral burst on the North side at N°3. We can also see that Building n°3 is more heavily damaged on its west side than on its east side (one level more still there).

Blast to the left, recoil to the right?

I agree that the north side is heavily damaged.

Could the blast have initiated above the SFP - and something recoiled out of the north side?

 

[razzz]

That unit 3 blast, just was not your run of mill blast. Couple of secondary explosion. Something was atomized or pulverized and sent through a narrow opening to be launched upwards like that. Super heated steam maybe causing the secondary explosions? Or trapped hydrogen beneath the reactor around the doughnut?

 

[jensjakob]

@Bez999

It looks to me like the fuel rods are in the chute, not the reactor. The lovely blue of the cherenkov radiation doesn't seem to open up any wider than the chute. The gates on the chute to both the SFP and the drywell containment are open, else I don't think you would see the blue color.

I stand corrected.

 

[jlduh]

INFO TO ALL CONTRIBUTORS AND READERS HERE:

Hi all, I just want to let you know that I posted a some new articles on an other thread that, after discussing yesterday with PF Mentor Borek, i created on the Forum.

The link to this new thread is:
https://www.physicsforums.com/showthread.php?p=3222895&posted=1#post3222895

This new thread is called The "more political thread" besides "Japan Earthquake: nuclear plants" scientific one and its title should be self explanatory,

but i added a first post to better clarify the goal of this thread in case it would be necessary. It is intended basically to be a place for discussing the "more political" infos around the accident in order to have a place to do it without doing it on this more technical and scientific thread, and I think it's really a good thing to separate the two threads and cross reference them when necessary (please in this case give link to the cross reference post number on each thread).

I posted this morning some new infos, concerning the "dosimeter affair" concerning Tepco (around 180 workers/day without dosimeters, many of them being subcontractors), and search about this subject, i found something that may interest people on this original technical thread (I don't think this element has been reported so far here). This is based on the declaration of one of the 3 workers who was sent to hospital last week with beta burns. I put the extract of the article that i source on the "more political thread" (i'll call it Brother Thread!). Cross reference post is #4 on the Brother Thread (let's adopt the convention that POL#4 will mean post number #4 in the "Brother thread"?)

I'm currently looking for the original Kyodo news article. If somebody finds it let it know.

Kyodo News interviewed one of the workers that was sent to the hospital with Beta Burns last week. It turns out the worker is a sub-sub-contractor. He said the reason they didn’t have protective gear is the fact that TEPCO has a lack of communication with its sub contractors. Tokyo Electric calls its sub-contractors ”associate enterprises.”

The injured worker suggests that the most dangerous work is being forced on the sub-sub-contractors. He claimed lack of supervision, and lack of radiation monitoring for the workers. Also, he says the problem with radiation levels is worse than what’s being reported. Many highly radioactive materials litter the nuclear plant’s compound, after the hydrogen gas explosions. They can not be removed because of their high levels of radiation.

Kyodo News found other sub-contractor employees who are no longer working at the plant. They said their employers begged them to come back to work, even offering 80,000 yen per day. They said no way, not with the amount of radiation there.

So it would indicate that there may have been high radioactive solid debris (not water I mean) spread around on the site at a level that "they couldn't be removed" (i guess with human intervention?).

What would that mean in termes of levels of radiation of this debris but also in terms of origin for this debris?

Feel free to discuss it or on the brother thread (POL thread: https://www.physicsforums.com/showthread.php?p=3222895&posted=1#post3222895 ) depending of the your judgment of what is relevant, and ORIENT people towards this new thread if you think this is necessary based on their post content (to avoid mix up).

 

[jlduh]

To JENSJAKOB:

Could the blast have initiated above the SFP - and something recoiled out of the north side?

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).

http://www.netimago.com/image_184910.html

This would imply of course a complete break of the containment structure there (and big lack of containment of radioactivity of course), and also that the highly contamined water of the Torus would be out in the basement... which can also be compatible with what has been found so far (the water in the basement of the turbine building has been found -3 workers injured- in a room just next to the torus room, i repost the drawing showing a cut of the buildings:

http://www.netimago.com/image_184913.html

 

[jlduh]

http://www3.nhk.or.jp/daily/english/01_03.html

Researcher explains how radiation reaches Tokyo

A Japanese researcher explained to NHK how radioactive substances that leaked from the crippled Fukushima Daiichi nuclear power plant have spread and reached Tokyo and other parts of the Kanto region.

Hiromi Yamazawa, a Professor at Nagoya University graduate school, says that high levels of radiation have reached Kanto at least twice since the nuclear plant accident.

He says the first incidence occurred from March 15th through the 16th. Contaminated air spread widely in Kanto.

The second occurred from the 20th through the 21st.

Contaminated air went south along the coast, and reached Chiba and Tokyo.

The air was then blown northwest to the inland prefecture of Gunma.

Yamazawa says the rain in a broad area of Kanto in the surrounding days deposited radioactive substances in rivers and contaminated water in purification plants in the region.

Yamazawa warns that radiation could more easily flow into Kanto from now to the early summer, due to winds blowing south from Fukushima during these seasons.

 

[AntonL]

Earthquake intensity report

This is the record of the earthquake intensity observed at the lowest
basement of the reactor buildings of Fukushima Daiichi Nuclear Power
Station and Fukushima Daini Nuclear Power Station when the
Tohoku-Taiheiyou-Oki Earthquake occurred approximately at 2:46pm on March
11th, 2011.

This report also contains Maximum Response Acceleration based on
"Regulatory Guide for Reviewing Seismic Design of Nuclear Power Reactor
Facilities (Revised in 2006)".
We will endeavor to keep collecting as much data as possible and examine
it in more detail.

The comparison between Basic Earthquake Ground Motion and the record of
the earthquake intensity observed at the lowest basement of the reactor
buildings of Fukushima Daiichi Nuclear Power Station and Fukushima Daini
Nuclear Power Station when the Tohoku-Taiheiyou-Oki Earthquake occurred.
[URL]http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110401_02.gif [/URL]

【Reference】
Threshold for reactor scram at each unit(The reactor automatically stops
if the intensity of the quake exceeds the threshold.)
[URL]http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110401_03.gif [/URL]
Glossary
· Observed Record of Earthquake Intensity
Record that indicates the intensity of an earthquake (Unit: gal)

· Regulatory Guide for Reviewing Seismic Design of Nuclear Power Reactor
Facilities
Revised in September 2006 based on the newly accumulated knowledge on
seismology and earthquake engineering and advanced technologies of
seismic design, this is a regulatory guide in reviewing the validity
of the seismic design of nuclear power reactor facilities.

· Basic Earthquake Ground Motion Ss
A basic earthquake ground motion in seismic design of facility,
stipulated in Regulatory Guide for Reviewing Seismic Design of Nuclear
Power Reactor Facilities

· Maximum Response Acceleration against Basic Earthquake Ground Motion Ss
Assuming Basic Earthquake Ground Motion Ss in the evaluation of the
earthquake-proof safety, this is the Maximum value of the quake of a
building, which is expressed in acceleration.

1 gal = 1 cm/sec ²

 

[jlduh]

I post it here because that can have impacts on analyses done on this thread, because it's about "all data on radiation leaked from the damaged Fukushima Daiichi nuclear plant"...

I won't comment to much, but for sure, scientific analysis can only lead to reliable conclusions IF source data are reliable. Which obviously some of them are not, for various reasons.

http://www3.nhk.or.jp/daily/english/01_28.html

Program errors force TEPCO to review all data
Tokyo Electric Power Company says it will review all data on radiation leaked from the damaged Fukushima Daiichi nuclear plant, citing errors in a computer program.

The utility says it found errors in the program used to analyze radioactive elements and their levels, after some experts noted that radiation levels of leaked water inside the plant were too high.

The company and the government's Nuclear and Industrial Safety Agency say previously released data may have shown the levels of tellurium-129 and molybdenum-99 to be higher than they really were.

But they say that levels of iodine-131, which has a significant impact on humans and the environment, remain unchanged.

Tokyo Electric releases data on radioactivity inside the plant compound and in nearby seawater and soil.
The radioactive substances are believed to be coming from damaged nuclear fuel rods.

The data is crucial for identifying the source of radioactive leaks and assessing their impact on the environment.

The Nuclear and Industrial Safety Agency has told the company to find out why the errors occurred and to take steps to prevent a recurrence.

 

[Cainnech]

I'm currently looking for the original Kyodo news article. If somebody finds it let it know.

Hi, I think it must be this article: http://english.kyodonews.jp/news/2011/03/82005.html

 

[artax]

I'm currently fascinated by the high res image (2011-3-30-1-11-12) which shows the Eastern faces of buildings 3 and 4.
It looks like the two remaining panels at the top of building 4 have been sucked in rather than blown out. I guess this is just the consequence of a directional explosion dragging air with it (as the Dyson ring fan thing does) but will give clues as to the location and direction of the (or one of the explosions, if we had an accurate 3D model of the building and it's rooms/wall strengths.
I still suspect a vertical hydrogen explosion in the near empty fuel pools, bu then how that damages the pressure vessels I've no idea.

 

[artax]

thx artax :)
here is the link to the full res http://cryptome.org/eyeball/daiichi-npp/daiichi-photos.zip

Sorry from this link. (seventh image in list)

It's very frustrating that they've not released the video of the number 4 explosion.

 

[AntonL]

Sorry from this link. (seventh image in list)

It's very frustrating that they've not released the video of the number 4 explosion.

does not exist as it was dark at the time - 6AM

 

[DosEnbier]

@jlduh
http://up.picr.de/6714926jvp.jpg

 

[artax]

does not exist as it was dark at the time - 6AM

So wouldn't we see it better!

@Dosenbier, that's unit 3,

What is your point?

 

[jlduh]

Thanks CAINNECH, great first posting!

For further "political" discussion around this, let's transfer to this thread on which i just posted your link:

https://www.physicsforums.com/showthread.php?p=3223014&posted=1#post3223014

(see post POL#8)

 

[|Fred]

@jlduh
http://up.picr.de/6714926jvp.jpg

I don't think so, for me it's rather part of the east wall

 

[artax]

In this image the two panels have been sucked inwards.

 

[jlduh]

Originally Posted by DosEnbier
@jlduh
http://up.picr.de/6714926jvp.jpg
I don't think so, for me it's rather part of the east wall

Courld you please clarify what you are talking about? Dosenbier and Fred?

 

[jlduh]

Very interesting ground video Shogun338...

I repost and ask if someone can locate the place shown at 3:43, the car is heading the sea and there is huge damage on the building on the left (panels blasted outwards). Can't figure out where it is based on Hi res aerial pics, should be close to a Turbine building but i don't see such damages on the Hires pics... Then the car turn to the North and again heavy panel damages



http://www.netimago.com/image_184936.html

 

[artax]

I was interested in that too, i think it's the far corner of the site near the sea outlet and the damage to the white building on the left is purely Tsunami damage.
They're obviously driving East towards the sea...I think it must be the next parallel rd just off the right of this image, see the tsunami damaged white building:-



there's a pipe then a white boom across the road.

 

[jlduh]

Except that to me it doesn't fit all the criterias:

- towards the sea
- one big building on each side of the road
- one pipe and one "bridge" crossing the road
- one place for passengers to cross the road (white stripes on the pavement)
- when your turn 90° left you have a big building in front of you 50 or 70 meters ahead

A tsunami wave would more probably push the panels inside the building, not outside like this, IMHO.
-

 

[|Fred]

DosEnbier thinks that the path of the concrete is the green line and is the shaff cap
I think its concrete from the east wall , since it has bleu plaint that the the path is in black

ps: I also located the path of the car and the location requested above

 

[artax]

Except that to me it doesn't fit all the criterias:

- towards the sea
- one big building on each side of the road
- one pipe and one "bridge" crossing the road
- one place for passengers to cross the road (white stripes on the pavement)
- when your turn 90° left you have a big building in front of you 50 or 70 meters ahead

A tsunami wave would more probably push the panels inside the building, not outside like this, IMHO.
-

Not the road shown, the next one right out of shot...that we don't have an image of. you see the pipe and other conduit on the roof, they will continue to the right out of the picture.
In the video they turn left and they can see the south end of the turbine building in front of them. then they go behind the tower (with it on their left) with the road in this shot to their left with red cones.

 

[AntonL]

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?

 

[jlduh]

Ok, i think i got it. This is the road going to sea just above (on the picture) the "antenna" (vent).

When turning left, the car has the turbine building fron No4 in front.

I'm still very surprised by the damage done to this building here (what is this building for by the way?), and doubt it comes from the tsunami looking at them.

 

[artax]

yes I'm pretty sure you've got it there in that satellite image, they've gone through the narrow gap inbetwee the two really tall buildings.
No Idea what tha building is though.
Anton's last post is pretty interesting! I sure hope they can fill that pool soon, could the release to the environment here become worse than Chernobyl? Surely it could if those fuel rod are just getting water splashed on them, they'll be corroding like crazy!

Oh dear.

 

[Maxion]

Ok, i think i got it. This is the road going to sea just above (on the picture) the "antenna" (vent).

When turning left, the car has the turbine building fron No4 in front.

I'm still very surprised by the damage done to this building here (what is this building for by the way?), and doubt it comes from the tsunami looking at them.

Do remember that the waves first com in, then go out. The materials looking like they're blasted outwards were most likely dragged by the water as it rushed back out to sea.

 

[Maxion]

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?

http://i1213.photobucket.com/albums/cc469/antonl1/sfp4.jpg

This is actually quite worrying, though I don't see the boxes he is referring to.

 

[artax]

I don't think he means 'boxes' really... I think he's referring to the lattice or grid like structure that the fuel assemblies slot into...it's a sort of rack, and the top of it is definitely bone dry.

Regarding these analysis results that they keep getting wrong, I assume they're using Gamma spectroscopy, so measuring wavelengths of emmitted gamma radiation.
Are they just getting confused with isotopes that give exactly the same wavelength, and having to use less populated lines for their analysis.
The more isotopes they have in there the more confusing it's going to get!

(I did a little neutron activation as an undergrad at the universities reseach reactor Manchester).

 

[|Fred]

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 .

 

[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.