Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[AntonL]

A video dated April 22 with images from the emergency centre and from the reactor grounds:

Via http://ex-skf.blogspot.com/"

more than just the control centre
a complete tour of the plant with new views from car level

 

[Varon]

I wonder why CNN no longer reports about the nuclear plants.. guess it's no longer serious and problems almost solved. (?)

 

[~kujala~]

Now the tsunami water cannot explain a rise in the last weeks from a level of 80cm to a level of 5m of course (if measured at the same spot, which we don't know about).

It's not the same spot, 80 cm from the turbine building [1] and 500 cm from the reactor building [2].
[1] http://search.japantimes.co.jp/cgi-bin/nn20110329a1.html
[2] http://www.foxbusiness.com/industries/2011/04/18/japan-nuclear-agency-reactor-building-4s-basement-filled-meters-water/

As for the waterproof systems I think the reactor buildings should be waterproof (but nobody knows if they still are) whereas the turbine buildings probably are not. It costs a lot of money to make waterproof systems everywhere and nuclear industry wants to save money, of course.

 

[jlduh]

I wonder why CNN no longer reports about the nuclear plants.. guess it's no longer serious and problems almost solved. (?)

Well, i can confirm that here in France, the medias have completely left this subject out. They just mentioned the 25 Anniversary of the Thernobyl accident and of course the various events and protests in relation with this. But Fukushima has disappeared from their scope. I guess they would probably show some images if some new explosions were happening. As i said in other places, radioactivity is invisible and complex, so this is not good for medias audiences...

More surprising the french IRSN has completely stopped (since almost one month) to report what is going on at Fukushima, except in a weekly basis but more for the french citizens leaving in Japan. So basically difficult, outside of this forum (and because we all now have recorded the links to where to go to compile infos) to follow what is going on there...

 

[MadderDoc]

[PLAIN]http://www.ic.unicamp.br/~stolfi/EXPORT/projects/fukushima/povray/blueprint/foto/edited/out/reactor4-S-1-A-i.png
(A larger version is http://www.ic.unicamp.br/~stolfi/EXPORT/projects/fukushima/povray/blueprint/foto/edited/out/reactor4-S-1-A-e.png
<..>
B - Markings left by the external staircase. It seems that the staircase was still there after the earthquake but before the explosion. Where did it go? is it buried under the rubble, or was it removed by workers early on?

The video taken on March 11th shortly after the tsunami shows a large portion of the staircase to be still on the building, except the uppermost part of the staircase which is missing. The video does not give a view to the lowermost part of the staircase close to the ground level to see whether is has sustained any damage, but it would be reasonable to expect at least some damage to it since this part of the staircase was inundated by tsunami water with floating debris.

H - apparently, the original location of the Mysterious Green Box, that seems to have disappeared after the earthquake, uncovering the Door With Mickey Mouse Ears.

After having exhausted as good as I think I can other possibilities to explain the combined visuals of Mysterious Green Box and Mickey Mouse, I end up with that the Green Box is a piece of equipment Tepco had affixed to the outside wall, and Mickey Mouse is the jagged hole remaining in the wall after something forcefully made this piece of equipment come off the wall.

The tsunami as the culprit for this cannot be excluded, however this is rather high up on the wall, so I find it most reasonable to categorize the coming off of the Green Box, as earthquake damage.

I - A huge grenish "closet", flush against that wall. The dark bands above it, leading to the terrace, are bundles of cables or pipes. Is that the Mysterious Green Box? Too big for that?

If you mean the apparent green box standing at the _foot_ of the wall, I think it is about the right size (I estimate the dimensions of the green box to be about 4 x 4 x 2 m). If the scenario of earthquake damage making the box come off is assumed, this is one of the places it could have ended up. It might initially have fallen down more or less vertically during the earthquake, taking with it the upper part of the staircase. The tsunami waters could then have made the box end up in this corner, behind other debris.

 

[etudiant]

Separate question.
Assuming that the SFPs are largely intact and only need to be topped up periodically, what does this mean for the environment?
About 250 tons of water are being boiled off daily. Is that steam a carrier for significant radioactive contaminants or is it pretty clean?
The question will take on additional interest as the summer winds and taifun season approach.

 

[zapperzero]

Is that steam a carrier for significant radioactive contaminants or is it pretty clean?

Common sense would suggest that it is not clean, but rather laden with whatever can be dissolved from the fuel rods or "steam-cleaned" off the inner walls (mainly Cesium which is an alkali, but also other things like Technetium, even Uranium directly from the rods).

 

[MadderDoc]

Those are control rods, are they not?

NHK news tonight pointed out some debris that can be seen on top of the fuel assemblies in this video (right of, and down from, center of zapperzero's image), but didn't point out anything else as being of interest. (Not sure they have had an expert look at it yet, though.)

For comparison purposes, here's a photo looking into the SFP of unit 3 during its refueling in 2010. It appears to have been taken in a place in the pool roughly equivalent to where the the imagery from SFP4 was taken (I believe close to the FPM)

 

[etudiant]

Common sense would suggest that it is not clean, but rather laden with whatever can be dissolved from the fuel rods or "steam-cleaned" off the inner walls (mainly Cesium which is an alkali, but also other things like Technetium, even Uranium directly from the rods).

Just as you say.
The question is whether the ongoing gradual decay mobilizes material incremental material, or whether the 'steam cleaning' already experienced will have pretty much purged the pools by now.

 

[fluutekies]

For comparison purposes, here's a photo looking into the SFP of unit 3 during its refueling in 2010. It appears to have been taken in a place in the pool roughly equivalent to where the the imagery from SFP4 was taken (I believe close to the FPM)

http://gyldengrisgaard.dk/daiichigrab/unit3/f1-26.JPG

Here is another view into a SFP: http://allthingsnuclear.org/post/3964225685/possible-source-of-leaks-at-spent-fuel-pools-at

What are the disks between the casks?
In the TEPCO video rising gas bubbles can be noticed: H2 from Zr-alloy? Or degassing of the UO2 pellets from the rods like Xe, Kr ..?

 

[fluutekies]

Separate question.
Assuming that the SFPs are largely intact and only need to be topped up periodically, what does this mean for the environment?
About 250 tons of water are being boiled off daily. Is that steam a carrier for significant radioactive contaminants or is it pretty clean?
The question will take on additional interest as the summer winds and taifun season approach.

Assuming non-criticality and no vigorous boiling, only the volatile content of the pool will enter completely into the atmosphere: H2O condensed as steam, all noble gasses, H2, O2, N2 etc .
If the pH of the pool is below 8, also HI, I2 will (partly) leave. Hopefully TEPCO added either sodium borate or neutralized the boric acid with lye to avoid acidifcation of the pool.
All metals, either as oxides or salts (ions) can not leave with the steam. But if a typhoon sucks up the water from the pool and disperse it with the wind, then it's a different story ...

 

[MadderDoc]

The recent data from the analysis of water from SFP4 would seem to me to be strong evidence of leaking. Taking account of the decay of iodine-131, the data for all three measured isotopes indicates that the pool has lost half of the content of soluble matter it had 14 days ago.
http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110429e13.pdf

 

[zapperzero]

In the TEPCO video rising gas bubbles can be noticed: H2 from Zr-alloy? Or degassing of the UO2 pellets from the rods like Xe, Kr ..?

Most probably it's water - the pools are not exactly cold. The noble gasses have all left by now. Could be hydrogen, depending on how hot those rods still are, but I doubt it. At 500 C or so, there'd be many more bubbles, no?

It doesn't really matter anyway because there's no containment where H2 from the pools can accumulate and eventually explode.

 

[NUCENG]

Um, sure...? It does look damaged. And half of the racks seem to be empty, which contradicts the "the SFP was overfilled" informations we have.
But I don't think that either of us knows how racks in a SFP look like... I'd like to hear Astronucs or NUCENGs opinion on this. What did TEPCO say?

Image for all who are to lazy to download the vid:

I see at least 16 fuel assemblies that appear to be totally intact in ther right corner of the fuel rack in the center of the picture. Bright shiny lifting bails (the diagonals you see) could be fresh fuel or used or spent.

I do see slabs and pieces of some kind of debris laying on tops of the bundles and in the bottom of the pool laying on top of what look to be cross members.

The racks along the wall to the left are not fuel racks. The ones at the top are too large and the ones with some sort of round caps are definitely not fuel.

The seven roughly cruciform shapes between the central rack and the fuel rack in the upper right may be control rod blades. The small lifting bail of a blade appears to be there.

In the central rack I see four positions in the corner at the top and five on the left side that appear to be empty. There may be some discoloration of these cells that may indicate heat and possibly melting down of fuel in those positions, I do not know which.

The other positions in that rack and in the other two racks visible may contain damaged fuel, or fuel assemblies with debris , or even just debris. Are their shadows in the pool such that only a few lifting bails appear shiny. Probably not because the tops of the racks look shiny and unmelted and intact.

I do not see any deformation or off kilter indications of an explosion that pushed stuff around. I would expect to see distortions and bent structures or even gaps if I was looking for conclusive evidence of explosion. Before you jump down my throat, that is not proof of no explosion, just a lack of proof that there was an explosion IN THIS CLIP.

I see debris moving around indicating turbulence or convection. Did they measure temperature of the pool? Were they pumping water into the pool? Probably not because the clarity of debris-filled water would probably not be so clear if they were spraying water through the debris over the pool.

I have stayed out of the photo interpretation game pretty much because it is simply too easy to see what we want to see. One of my first posts asked for people to let me know when they spotted Osama ibn Laden.

When you are performing photo reconnaissance and interpretation remember the observer who was aked what color the barn was. A good analyst would reply, "It is red, on this side."

 

[zapperzero]

Did they measure temperature of the pool? Were they pumping water into the pool?

My bet is this is the camera that was attached to the rig they used to get a water sample.

 

[jlduh]

The recent data from the analysis of water from SFP4 would seem to me to be strong evidence of leaking. Taking account of the decay of iodine-131, the data for all three measured isotopes indicates that the pool has lost half of the content of soluble matter it had 14 days ago.
http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110429e13.pdf

When i look at these numbers and compare them to the ones from the analysis of the sub drain water (they are all in Bq/cm3),
http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110428e14.pdf

i have a hard time to understand why the ones from the SFP are not much higher...

What can explain these so low numbers in comparison with the subdrain levels? Are the subdrain so heavyly contaminated that the level ae actually higher than in the SFP?

 

[ascot317]

I wonder why CNN no longer reports about the nuclear plants.. guess it's no longer serious and problems almost solved. (?)

News Media "Interest" in any topic has a half time of two weeks, unless something "new" happens.
Same with Libya. The plant is still a serious problem.

 

[NUCENG]

why put fresh fuel into SPF anyway? Fresh fuel is much more reactive, and requires more boron...

Fresh fuel is valuable and fragile. It is as much to protect the new fuel as anything else. After receit inspection and channeling, it is put into the pool ready to be picked up and loaded into the core. Fuel pool racks have boron neutron absorber as you recall (BORAL) and thet is sufficient to keep them subscritical. Reactor engineers also evaluate fuel placement to ensure Keff stays in the safet range. Why would it be unsafe to store new fuel in the pool?

 

[bytepirate]

The recent data from the analysis of water from SFP4 would seem to me to be strong evidence of leaking. Taking account of the decay of iodine-131, the data for all three measured isotopes indicates that the pool has lost half of the content of soluble matter it had 14 days ago.
http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110429e13.pdf

a rough calculation gives a loss of 50 tons per day. assuming, that cesium can not leave but through a leak, and the water level is held constant by refills.
on the other hand: if the pool was filled only half at the time of the first measure and now is full, the result would be the same. do we know?

 

[zapperzero]

News Media "Interest" in any topic has a half time of two weeks, unless something "new" happens.
Same with Libya. The plant is still a serious problem.

Here's your fresh news: http://online.wsj.com/article/BT-CO-20110429-708521.html" .

 

[ascot317]

Here's your fresh news: http://online.wsj.com/article/BT-CO-20110429-708521.html" .

Nah, that's just background noise. "New" would be something breaking up, exploding, someone getting killed etc. Which could still happen.

That adviser seems to be exactly the right guy to do advising.

 

[RealWing]

Nah, that's just background noise. "New" would be something breaking up, exploding, someone getting killed etc. Which could still happen.

That adviser seems to be exactly the right guy to do advising.

I have great respect for someone with strong public safety principles. Another 'hero" emerges from this event.

 

[MadderDoc]

a rough calculation gives a loss of 50 tons per day. assuming, that cesium can not leave but through a leak, and the water level is held constant by refills.
on the other hand: if the pool was filled only half at the time of the first measure and now is full, the result would be the same. do we know?

You are right, that's a possibility we cannot exclude, although the levels being only half of what's in it now stretches my imagination, I don't think it is full now.

What we know from the data that has been released (http://www.gyldengrisgaard.dk/fuku_docs/fuku_sfp_sprayings.html) is there seems to have been a 3 day lull in the sprayings to SFP4 up to the sampling on March 12th. We know also that shortly after midnight the night after the sampling (00:30 on March 13th), spraying to the pool commenced and continued throughout the night, for six and a half hour, one of the longest spraying periods recorded.

 

[MiceAndMen]

SFP #4 underwater video ! http://www.tepco.co.jp/en/news/110311/images/110428_1.zip
We can see that upper parts of fuel sets are melted

To this layman's eye, there seems to be very little obvious damage. Some zircaloy somewhere in that pool must have oxidized to generate the hydrogen that exploded, and maybe the fuel seen here is damaged down below where we can't see, but I see very little physical damage.

This is but one section of the SFP where little has fallen in on top of the racks. The four 6 x 10 racks visible in the video have space for 280 assemblies total, about 20% of the total number of assemblies in the pool. They don't all seem to be full, meaning we're seeing somewhat less than 20% of the assemblies. I'd love to see what the rest of the racks look like.

People claiming to see damage lurking behind every little shadow of video have overactive imaginations IMO. This video, at least to my untrained eye, is reason to hope that the SFP in Unit 4 is not a huge jumbled mass of chaos and twisted metal.

 

[AntonL]

The recent data from the analysis of water from SFP4 would seem to me to be strong evidence of leaking. Taking account of the decay of iodine-131, the data for all three measured isotopes indicates that the pool has lost half of the content of soluble matter it had 14 days ago.
http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110429e13.pdf

Leaking can be very quickly confirmed by the salt content of the pool, the pool was cooled by adding sea water from March the 20, which has been concentrated by the continuous boiling. March 30 was the first day fresh water was used.
I suppose a salinity test would be too innovative and too simple for Tepco

SFP4 radioactivity is a fraction to what was measured in SFP2
extract from http://www.nisa.meti.go.jp/english/files/en20110421-1-5.pdf page 9

The work of sampling water that flowed out in the Skimmer Surge Tank
from the Spent Fuel Pool was carried out in order to grasp the condition
of water in the pool. (April 16th) As a result of nuclide analysis of
radioactive materials regarding the sampled water of the pool,
4.1×10³Bq/cm³ of 131 I (Iodine),
1.6×10⁵:Bq/cm³ of 134 Cs (Cesium),
1.5×10⁵:Bq/ cm³ of 137 Cs (Cesium)
were detected. (April 17th

 

[MiceAndMen]

I suppose a salinity test would be too innovative and too simple for Tepco

My thoughts exactly.

 

[MiceAndMen]

For a rough estimate of the length and width of buildings, the plant layout map should be able to yield data of sufficient precision:
http://gyldengrisgaard.dk/fuku_docs/plant/

Good estimates of the W and L of the reactor buildings might be of great utility to others, so do not hesitate to post them.

The measurements on the diagram are not consistent. When scaled appropriately along the Y axis (I used Autocad), the distances between the X coordinates are way off. And vice versa. I would trust the XY numerical values given, but simply tracing the outlines of things will not yield accurate shapes or positions.

 

[etudiant]

The measurements on the diagram are not consistent. When scaled appropriately along the Y axis (I used Autocad), the distances between the X coordinates are way off. And vice versa. I would trust the XY numerical values given, but simply tracing the outlines of things will not yield accurate shapes or positions.

Would it be sensible to use the Google Earth images to set the proportions and then derive the floor plan dimensions from that?
Admittedly, that does not help for interior partitions or depth. so this may be a dead end.
In any event, TEPCO is projecting up to 200,000 tons of water in the plant, so that gives a minimum volume.

 

[Caniche]

a rough calculation gives a loss of 50 tons per day. assuming, that cesium can not leave but through a leak, and the water level is held constant by refills.
on the other hand: if the pool was filled only half at the time of the first measure and now is full, the result would be the same. do we know?

JAIF status report details the spraying of 650 tons of freshwater into SPF4 over the period 23-26/4 . Steam and mirrors?

 

[Caniche]

Bloomberg reports robots reading 1,120 mSV/h in reactor building 1 on 26/4 , that's not good is it?
Tepco reckons the readings might be a tad too high to allow their plan to flood the "drywell "containment to proceed.
Hmm, surely flooding the outer containment structure will only guarantee submersion of the remaining core if the RPV containment is breached at a high level /or high level venting of extreme radioactive material is still physically possible?