Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[MiceAndMen]

I am attaching horizontal views of Fukushima 1 unit 1, looking north and looking west. Units 2-5 are somewhat different, but it should still be a useful reference.

Thanks, but those are hardly new. The drawing of the refueling floor in Unit 4 is new and finally confirms the layout of the reactor well, the SFP and the oblong equipment pool. A lot of what we had surmised about the layout is now confirmed.

In the same pdf, I'm having trouble placing the bottom left photo with regards to where the camera was positioned and which way it is pointing. The caption may be wrong as well.

 

[SteveElbows]

Here is another photo from their adventure on the refuelling floor at reactor 4:

http://www.tepco.co.jp/en/news/110311/images/110701_1.jpg

Finally a view of the spent fuel pool that puts much in perspective, including the large round area that is partially separated from the rest of the pool. We can now see why it has a square round it on diagrams.

 

[joewein]

how can there be no new Iodine-131 when there is
800 tons of corium laying about all over the place
at Fukushima Daiichi?

I'm not sure where you got that figure.

Unit 1 contained 68 t of fuel while units 2 and 3 contained 94 t each. Therefore, assuming their cores completely melted, the amount of corium should be roughly a third of the figure you gave.

Second, it's been 111 days since the active reactors in Fukushima were shut down. That means tomorrow it will be 14 full half lives of I-131. Whatever amount of cesium existed on March 11, whether it stayed inside the plant or escaped into the environment, only 1 / 4096 of it still exists. 99.976% of it has since decayed. Even if some I-131 still escaped with steam, it probably was decaying faster outside than it could be replaced by ongoing releases.

By now the major problem is cesium, not I-131.

 

[SteveElbows]

In the same pdf, I'm having trouble placing the bottom left photo with regards to where the camera was positioned and which way it is pointing. The caption may be wrong as well.

The caption isn't brilliant, but I have some sense of where this photo is taken, due to the yellow containment cap location which we know well.

Camera is pointing North, so equipment pit is in the far distance. Reactor well is just in front of cameraman, and cameraman could probably have shot the next photo of the reactor well without moving, just by pointing camera down and to the right somewhat. This may not be what actually happened, as reactor well photo may have ben taken from opposite side, I am just trying to illustrate what I believe to be the camera position relative to reactor well in the photo you mention.

 

[joewein]

The caption isn't brilliant, but I have some sense of where this photo is taken, due to the yellow containment cap location which we know well.

Camera is pointing North, so equipment pit is in the far distance. Reactor well is just in front of cameraman, and cameraman could probably have shot the next photo of the reactor well without moving, just by pointing camera down and to the right somewhat. This may not be what actually happened, as reactor well photo may have ben taken from opposite side, I am just trying to illustrate what I believe to be the camera position relative to reactor well in the photo you mention.

I think you got the direction right, but I believe it was taken just a few meters further south, perhaps next to the green "bridge" (which I presume is the "Fuel Exchange Truck", a crane).

When you look at the http://www.tepco.co.jp/en/news/110311/images/110701_1.jpg" and the right one showing the pool gate, while the middle one of the reactor well shows the rusty one.

I wish those two structures where shown on the floor map as the green one is.

 

[clancy688]

Unit 1 contained 68 t of fuel while units 2 and 3 contained 94 t each. Therefore, assuming their cores completely melted, the amount of corium should be roughly a third of the figure you gave.

Corium does not only consist of fuel elements, but also of everything else which melted because of the immense decay heat: Control rods, RPV steel, concrete... so you'll get more corium than there were fuel rods.

Still that 800 ton number is probably way to big...

 

[hellbet]

ITherefore, assuming their cores completely melted, the amount of corium should be roughly a third of the figure you gave.

Corium is not only made of melted fuel but also incorporates control rods, melted steel from RPV, rods support assembly and probably a lot of other "stuff" like pipes, bolts... If 100% or each core has melted through RPV, total corium weight might be initially around 260 T (Fuel) + all other stuff surrounding that "hot affair".

 

[SteveElbows]

I think you got the direction right, but I believe it was taken just a few meters further south, perhaps next to the green "bridge" (which I presume is the "Fuel Exchange Truck", a crane).

When you look at the http://www.tepco.co.jp/en/news/110311/images/110701_1.jpg" and the right one showing the pool gate, while the middle one of the reactor well shows the rusty one.

I wish those two structures where shown on the floor map as the green one is.

Yeah you are probably right. Actually looking at the angle that the bottom left photo on the pdf was taken at, it seems to be looking down on quite a lot of this stuff, so I think they may have climbed at least some of the steps of the green refuelling structure before taking the photo.

As for the two white bridges, I think there may actually be three structures. One to the south of the reactor well, one to the north of the well that we can barely see, and the slightly rusty structure that's over the reactor well is suspended from these other two by way of the beams that are oriented north-south that we can see near the top of the photo.

And just for the sake of avoiding any confusion by others reading this discussion, the yellow containment cap is in the distance and hardly looks yellow in the photo of the fuel pool, the more obviously yellow thing in that photo is something else.

 

[robinson]

We know that 50 pounds of Plutonium in one place is enough to get a nuclear reaction. With over a ton in the melting mass it would be easy to imagine a reaction happening, which then causes the mass to disperse, then another blob forms, random short critical masses forming and being blown apart at random. Plutonium doesn't need a neutron moderator to go critical.

 

[SteveElbows]

Hence the radioactive Iodine spikes. Weather can not find a hidden reservoir of Iodine that it suddenly taps. I suppose Iodine can be concentrated in the mist in rain clouds, but was it raining from lingering rain clouds every time there was a spike? I don't think so.

I keep an open mind about what is possible, its just that so far I have not seen evidence that is strong enough for me to properly buy into criticality theories. I can partially buy into the idea that it could have happened in the very early days of the disaster, but there just has not been any later developments with on site radiation levels that were interesting enough to make me dwell too much on whether it happened again after March.

I think you may need to study the scale which is used on that graph. The spikes are really not as impressive as you may be thinking they are.

 

[jim hardy]

i have to think they got a handle on preventing criticality pretty early on. i remain suspicious about unit 3 explosion, but am waiting patiently for more info..

Around 20 March was a temporary increase in injection rate of water to unit 3 and jorge stolfi's plots show they were able to cool the reactor using their fire trucks.
http://www.ic.unicamp.br/~stolfi/EXPORT/projects/fukushima/plots/cur/out/plot-un3-t-I-full.png
That to me ruled out ongoing criticality , for were that monster critical it could boil a swimming pool dry in twenty seconds and they would not have been able to achieve the 100C reading on "core nozzle temperature" the brown line.Here's excerpt from something i wrote way back in May on another forum, about Jorge's unit 3 plots - repeated here really just to point out what a great job he did with those charts.

Now select the TCb X Pc plot. http://www.ic.unicamp.br/~stolfi/EXPORT/projects/fukushima/plots/cur/out/ptmp-TCn-PCA-un3-full.png [/URL] That one's easy. The bottom of vessel has always been hot enough to boil the water in the vessel. Well except for a couple readings and it'd be logical they pushed their injection up to verify they could cool it. That would be smart for it'd positively rule out ongoing criticality and is something an egghead would think of. Or it could be just that they were getting the hang of controlling temperature with fire pumps. On second thought it would make real good sense to do that experiment given the press speculation about ongoing criticality and could be the basis they asserted in the press release about Neutron Beams "no criticality has occured."[/quote]


[url]http://tickerforum.org/akcs-www?post=182121&page=314[/url]

 

[robinson]

http://www.tepco.co.jp/nu/f1-np/camera/index-j.html

Wind blowing off shore. reactors/fuel ponds steaming like crazy at the moment.

 

[MadderDoc]

I think you got the direction right, but I believe it was taken just a few meters further south, perhaps next to the green "bridge" (which I presume is the "Fuel Exchange Truck", a crane).

When you look at the http://www.tepco.co.jp/en/news/110311/images/110701_1.jpg" and the right one showing the pool gate, while the middle one of the reactor well shows the rusty one.

The south beam of the white crane structure is not visible in the middle photo because it is shot standing on it :-) towards the north and rusty beam.

I wish those two structures where shown on the floor map as the green one is.

I have marked up the floor map and two of the photos you speak of, it may help to show the approximate position of the white crane construction, and the different positions and angles of the camera of the two photos.

 

[greenpharao]

Guys, I think some of those spikes in Iodine were the results of some ongoing criticality somewhere in the Fukushima site.

Do you guys remember Arnie's "Breathing" comments on Reactor One? Do you remember the detection of Neutron Beams outside of the reactor buildings? I don't know that I ever saw a complete explanation about that. We probably never will get one either.

According to the gamma radiation readings (CAMS) of Unit 1's Drywell B there is still a lot of on/off activity happening. I'm no scientist, but I think this data-graph speaks for itselves:

Source:http://www.ianbradshaw.co.uk/multimedia/fukushima/tepco.html
----------------------------------------
Can anyone interpret these spikes?

 

[nikkkom]

According to the gamma radiation readings (CAMS) of Unit 1's Drywell B there is still a lot of on/off activity happening. I'm no scientist, but I think this data-graph speaks for itselves

Can anyone interpret these spikes?

300 Sv/h is 30000 R/h, which is very high dose.

If it's caused by periodic criticality, there would be *a lot* of neutrons, hard to miss. Therefore I highly doubt it. Even TEPCO would not be arrogant enough to think it can hide it.

My guess is, broken sensor, or intermittently shielded blob of corium nearby, such as: corium periodically covered by water. When it's covered (-> shielded), activity is low. When it isn't, it's through the roof.

 

[StrangeBeauty]

According to the gamma radiation readings (CAMS) of Unit 1's Drywell B there is still a lot of on/off activity happening. I'm no scientist, but I think this data-graph speaks for itselves:

----------------------------------------
Can anyone interpret these spikes?

I am not qualified to authoritatively speak to ongoing recriticality or its possible variants, but there are three pieces of evidence about that particular sensor (#1 CAM B):

1) it has been marked as 'under survey' (aka broken) by tepco for a long time now
2) the sister sensor (CAM A) shows no such spikes
3) all of the temp sensors for #1 shows no evidence of spikes

btw, that site has some nice dynamically generated graphs.

P.S. belated thank you to MiceAndMen for pointing out that my #3 possibility in my previous post (where the fuel might currently be) could eliminated from consideration. :)

 

[MiceAndMen]

Here is another photo from their adventure on the refuelling floor at reactor 4:

http://www.tepco.co.jp/en/news/110311/images/110701_1.jpg

Finally a view of the spent fuel pool that puts much in perspective, including the large round area that is partially separated from the rest of the pool. We can now see why it has a square round it on diagrams.

Yes it is a very useful photo. I'd love to see all the other photos they took on their little fact-finding mission to the 5th floor. Unfortunately we've gotten to the point - have been there for quite some time actually - where radiation isn't the only thing TEPCO is trying to contain.

 

[MiceAndMen]

Here is another photo from their adventure on the refuelling floor at reactor 4:

http://www.tepco.co.jp/en/news/110311/images/110701_1.jpg

Finally a view of the spent fuel pool that puts much in perspective, including the large round area that is partially separated from the rest of the pool. We can now see why it has a square round it on diagrams.

Fuel cask drop. Like a drydock for fuel assembly shipping casks. With all due respect to TCups, his contention that there was a separate small pool for the processing of fuel for shipping, was incorrect. I miss TCups' contributions nonetheless.

 

[MiceAndMen]

The caption isn't brilliant, but I have some sense of where this photo is taken, due to the yellow containment cap location which we know well.

Camera is pointing North, so equipment pit is in the far distance. Reactor well is just in front of cameraman, and cameraman could probably have shot the next photo of the reactor well without moving, just by pointing camera down and to the right somewhat. This may not be what actually happened, as reactor well photo may have ben taken from opposite side, I am just trying to illustrate what I believe to be the camera position relative to reactor well in the photo you mention.

That is more or less my take on it as well. We know the cap is on the west side of the floor, so the camera pointing north makes sense. The damaged roof at the north side also fits the external photos we've seen. The equipment pool is likely the farthest thing away in the picture, extending back towards the north wall (or what's left of the north wall), and the caption seems to say the opposite.

 

[MiceAndMen]

I wish those two structures where shown on the floor map as the green one is.

It's hard to say what the whitish structures are. Obviously they've got cranes on them. My guess is they're special equipment needed for the core shroud replacement work, and wouldn't appear in the original blueprints at all. Regardless, they could have been drawn in overlaid on the floor plan, so I'm with you there. It would have made things clearer. I also have to go back and look at the pictures taken from the outside by the aerial survey and T-Hawk drones. I don't remember seeing the white bridge-crane support steel anywhere before these latest pictures.

 

[LabratSR]

According to the gamma radiation readings (CAMS) of Unit 1's Drywell B there is still a lot of on/off activity happening. I'm no scientist, but I think this data-graph speaks for itselves:

Source:http://www.ianbradshaw.co.uk/multimedia/fukushima/tepco.html
----------------------------------------
Can anyone interpret these spikes?

If you look at the bottom of the second page you will see the CAMS data marked as "Instrument Failure" This is from the TEPCO Status page.

http://www.tepco.co.jp/en/nu/fukushima-np/f1/images/11070106_level_pr_data_1u-e.pdf

 

[SteveElbows]

I haven't seen this posted yet, sorry if it has been.

English Version of Timeline Released.

http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110618e15.pdf

Ah its good to see the translation of that document, I've been looking forward to it.

I don't think it ends up adding a huge amount to the picture we have, but in a few places it helps a bit with some details, including a few that we have wondered about in this thread in the past.

For example, I know there was a discussion about some other document that mentioned valve opening operations at reactor 2 being hampered by the explosion at reactor 3. But we couldn't find the detail. Well, there is a bit more info about this in the freshly translated document you link to.I'm a bit too tired to highlight the specifics right now, maybe whoever else I was talking with about this in the past would like to do the honours.

Another thing it helps a little with is getting a bit more detail about radiation rises & conditions in the reactor, turbine & control room buildings early on, and what humans went into them to do crucial things at certain points.

 

[tsutsuji]

http://www.nikkei.com/news/headline...19595E2E0E2E2E68DE2E0E2E5E0E2E3E39F9FE2E2E2E2 : Although the flow of water has been restricted to 3 ~ 9 m³/h lately, it is planned to increase it very soon - on 4 July or a few days sooner or later - in order to enhance the cooling of the reactors, when Tepco is confident that the decontamination system is stable enough. Minister Goshi Hosono confirmed that the goal is to run it with an 80% utilization rate (from the 1200 ton/day flow). The diagram in the article is a depiction of the roadmap, where the blue color represents Areva technology :

Step 2 : July-January : study and implementation of heat exchanger (grey) | decontamination, sludge storing and treatment (blue)

Middle term issues : January and later : removal of fuel (blue) | sludge treatment (blue)

Among the sensitive issues that could pay their toll on the plan to decontaminate all the 110,000 tons of contaminated water by the end of this year are the danger of leaks in the 4 km long pipes and how rainfalls may increase the quantity of contaminated water.

http://www.asahi.com/national/update/0702/TKY201107020452.html : From 2 July in the evening, the reliance on fresh water from the dam has been set to zero, which means increasing the use of water from the decontamination facility and limit the quantity of contaminated water.

 

[MadderDoc]

<..>there was a discussion about some other document that mentioned valve opening operations at reactor 2 being hampered by the explosion at reactor 3. But we couldn't find the detail. Well, there is a bit more info about this in the freshly translated document you link to. I'm a bit too tired to highlight the specifics right now, maybe whoever else I was talking with about this in the past would like to do the honours.

It was me you were talking with about it, and you are right there are pieces of the puzzle in this document that seems to shed more light. I haven't finished laying them as regards this particular aspect though :-) .. but will report back when and if a clear picture emerges.

I am very happy with this document, now translated to English, already on first reading it yielded me several Rosetta stone moments, and I am sure there is more to be gained from it.

 

[Bodge]

In what state is the Iodine-131 that is being detected 200 miles away in Gunma Prefecture ?

I would assume that the Japanese detector is measuring gaseous Iodine ?

How can there still be 'pockets' of I-131 gas remaining since March, which periodically are blown by the winds towards Gunma ?

Surely any I-131 would have been dispersed months ago ?

Is there some mechanism for the continued release of 'trapped' I-131, produced in March ?

[PLAIN]http://www.bfs.de/de/ion/imis/ctbto_aktivitaetskonzentrationen_jod.gif

 

[nikkkom]

In what state is the Iodine-131 that is being detected 200 miles away in Gunma Prefecture?

In the form of tiny amounts of iodine salts in water (say, tiny water droplets in air). Really, really tiny amounts.

I would assume that the Japanese detector is measuring gaseous Iodine?

No.

How can there still be 'pockets' of I-131 gas remaining since March, which periodically are blown by the winds towards Gunma?

Iodine was everywhere around Fukushima, but since many its compounds are volatile or soluble, it disperses from there.

Surely any I-131 would have been dispersed months ago?

No, only noble gases disperse that quickly. Iodine is less mobile, Cesium is even less mobile.

 

[imandylite]

'Worriar' vacuum cleaning robot

Cleaning the floor of reactor unit 3

https://www.youtube.com/watch?v=SnA4kHQ2xeA

 

[joewein]

Fuel cask drop. Like a drydock for fuel assembly shipping casks. With all due respect to TCups, his contention that there was a separate small pool for the processing of fuel for shipping, was incorrect. I miss TCups' contributions nonetheless.

Thanks for confirming that. I had just asked my son to try and decipher the kanji characters and he concluded it was for moving fuel out of the pool, so it had to be for dry casks.

The two circles in the corners next to the reactor pit and next to the north-east and north-west corners of the SFP are marked as "skimmer surge tank hatch".

 

[joewein]

In what state is the Iodine-131 that is being detected 200 miles away in Gunma Prefecture ?

I would assume that the Japanese detector is measuring gaseous Iodine ?

I doubt much of any of the radioisotopes (with the exception of noble gases) is in elementary form. Iodine would be in the form of salts.

How can there still be 'pockets' of I-131 gas remaining since March, which periodically are blown by the winds towards Gunma ?

Surely any I-131 would have been dispersed months ago ?

I am wondering if dust could be traveling with wind? Here in Tokyo we sometimes get parked cars covered in yellow dust from sand storms in China's Gobi desert!

This wouldn't have to be dust traveling all the way from Fukushima. A lot of fallout came down with rain between about March 14 and March 24. The rain ran off or dried up, leaving contaminated dust on the ground. Relatively high doses have been measured around drains by the side of the road where the water entered the canalization, as well as in sewage treatment plants for that reason.

Depending on how high above the ground the detector in Gunma is located, it may pick up some of that dust only when it temporarily gets whipped up by strong winds. The "official" radiation meter for Tokyo in Shinjuku is 18 m above ground level.

There may be other plausible explanations, this is just one I can think of.

 

[Borek]

Iodine can be in elementary form.