Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[Borek]

then you are saying that TEPCO is saying that there is next to zero radioactivity (these three isotopes) at the main gate?

No, I am just explaining what the result means.

 

[clancy688]

The following document, which I have mentioned at least once before in this thread and which is in Japanese, seems to contain a wealth of information about how they estimate contamination, far more than we usually get. Its from an NSC meeting (meeting 31). Computer translation does not do a perfect job of revealing the details in their full glory, but give it a try and you should at least see what I mean. There are a few tables and charts there too which require almost no translation to understand. And the one on the very last page shows a timeline of release magnitude which really helps to get a sense of the picture they have established when collecting data and doing their analysis of what happened.

http://www.nsc.go.jp/anzen/shidai/genan2011/genan031/siryo4-2.pdf

Big thanks! The graph is interesting indeed.

There was a MAJOR C137 release going on for at least one day between March 30th and 31st. 100 TBq/h, makes 2400 TBq C137. Converted value: 96.000 TBq, over 10% of the total number. That alone would be sufficient for an INES 7 classification. What happened that day?

Or is this a mistake on my part, did I read the chart wrong?

In case it's real: Then screw my previous comments about airborne releases and the number not rising anymore - in that case, those are wrong of course.

 

[causeceleb]

No, I am just explaining what the result means.

well, i thought 9.5E-06 meant 9.5 times 10 to the minus 6, but
the whole thing just threw me for a loop.
thank you for helping me grab hold of reality :)

 

[SteveElbows]

Yes but this new water injection system is almost the same as concrede pump, so this shouldn't act on sst water level
interesting data and photos from today about unit 4:
http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_110630_03-e.pdf

Photos are interesting. I am pretty sure that some of the stuff seen is an off-white colour because earlier in June they sprayed the anti-scatter substance onto the roof of reactor 4. This could also be what the gunk around one of the photographed valves is, although I cannot be sure.

Good to see the gate between the fuel pool and the reactor well, good to see the reactor well full of water. I wonder if the water level will stay stable.

Do you care much now about the reported skimmer surge levels? To add to list of possibilities regarding what has changed, I suppose it is possible that gate between fuel pool & reactor well still had a leak, and now they have filled up the reactor well, water is not being lost from fuel pool so quickly, so less filling required? Anyway it seems that I was probably wrong to suggest that maybe they use the new water system on a more continuous basis, since I checked recent status reports and brief injections via this system have been reported in recent days.

Another possibility is that since completion of steel structural support under fuel pool, they feel they have more options available to them, perhaps they were avoiding certain things because of fear of structural failure. For example I don't think they started filling the reactor well & storage pit with water until the first phase of structural support work was done, but this could be a mere co-incidence of timing for all I know.

 

[Bodge]

The CTBTO monitoring is back.

I find the I-131 peaks to be indicative of ongoing fission somewhere on the site.

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

 

[SteveElbows]

Big thanks! The graph is interesting indeed.

There was a MAJOR C137 release going on for at least one day between March 30th and 31st. 100 TBq/h, makes 2400 TBq C137. Converted value: 96.000 TBq, over 10% of the total number. That alone would be sufficient for an INES 7 classification. What happened that day?

Or is this a mistake on my part, did I read the chart wrong?

In case it's real: Then screw my previous comments about airborne releases and the number not rising anymore - in that case, those are wrong of course.

I don't think you are reading the chart wrong,but due to a lack of official narrative about air release events past the first week, I cannot really tell you what happened on that day, but I do intend to look into it further again sometime. It was the even higher magnitude release estimated for a time on March 15th that got most of my attention when I first found this document.

As for the number not rising significantly anymore, using computer translation of that NSC document I am fairly sure their estimated total releases covers the entire period shown in that graph, so their figure of 630,000 TBq covers the includes the end of March figure you mention. Actually this document also shows that they slightly revised upwards their calculation for total release of Caesium. Using INES conversion I think the new NSC-calculated total release for period up to 6th April was 670,000 TBq. Crucially I don't think any high magnitude releases beyond the dates covered by this report have been mentioned, so I believe your point that later daily releases don't make very much difference to the estimated total is still valid.

 

[SteveElbows]

The CTBTO monitoring is back.

I find the I-131 peaks to be indicative of ongoing fission somewhere on the site.

I believe we still need to check for other factors which could cause spikes in such data. For example weather.

 

[clancy688]

I am fairly sure their estimated total releases covers the entire period shown in that graph, so their figure of 630,000 TBq covers the includes the end of March figure you mention. Actually this document also shows that they slightly revised upwards their calculation for total release of Caesium. Using INES conversion I think the new NSC-calculated total release for period up to 6th April was 670,000 TBq. Crucially I don't think any high magnitude releases beyond the dates covered by this report have been mentioned, so I believe your point that later daily releases don't make very much difference to the estimated total is still valid.

Well, there's a problem. On page 4 there's another chart showing exact values and time periods. I used it to calculate the whole C137 release (no time for I131, maybe tomorrow). Released Cesium (per hour) is (Release Rate / (1 + I/C Ratio)).
But I'm coming 2000 TBq short. NSC's estimate was a release of 12.000 TBq C137. I only get 10.000 using their numbers.
Oh, and the exact C137 release for March 30th-31st would be 1900 TBq (unconverted) or 75.000 TBq (converted).

 

[Bioengineer01]

I don't think you are reading the chart wrong,but due to a lack of official narrative about air release events past the first week, I cannot really tell you what happened on that day, but I do intend to look into it further again sometime. It was the even higher magnitude release estimated for a time on March 15th that got most of my attention when I first found this document.

As for the number not rising significantly anymore, using computer translation of that NSC document I am fairly sure their estimated total releases covers the entire period shown in that graph, so their figure of 630,000 TBq covers the includes the end of March figure you mention. Actually this document also shows that they slightly revised upwards their calculation for total release of Caesium. Using INES conversion I think the new NSC-calculated total release for period up to 6th April was 670,000 TBq. Crucially I don't think any high magnitude releases beyond the dates covered by this report have been mentioned, so I believe your point that later daily releases don't make very much difference to the estimated total is still valid.

Did you guys look at the way the releases acknowledged by TEPCO in the document you mentioned are reflected in the CTBTO charts, posted before? Is it reasonable to back extrapolate from that and take a rough guess at newer non-reported releases at later dates from the peaks in the graphs? Am I making sense?

 

[LabratSR]

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

 

[tsutsuji]

The daily Kurion-Areva facility trouble :

http://sankei.jp.msn.com/affairs/news/110630/dst11063022440037-n1.htm (and http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_110630_05-e.pdf ) : On 30 June the decontamination facility was stopped for flushing between 10:46 AM and 1:35 PM. The facility was restarted but after one hour it had to stop again because of an alarm signalling that gasses are unable to evacuate through the exhaust stack at the Areva facility.

http://www.nikkei.com/news/headline...19481E1E2E2E19A8DE1E2E2E4E0E2E3E39797E0E2E2E3 The facility started again at 6:50 PM (30 June).

http://mainichi.jp/select/jiken/news/20110701k0000e040075000c.html the reason of the trouble was a mistake in the control of the water level in a tank. Although the water level must be set at 3% above the bottom when the facility is stopped and 30% when it is running, the facility had been started with the level still set at 3%.

http://www.nikkei.com/news/headline...19595E2E3E2E2E58DE2E3E2E5E0E2E3E39790E0E2E2E2 : from 1 July to 4 July, Tepco will be installing a new water tank whose purpose is to centralise the two water routes (the route from the filtrate tank, and the route from the water purification facility) that take water to the reactors. The new tank will have a 1000 ton capacity. On 1 July the cooling is switched back to the filtrate water tank. The new "buffer tank" is shown on the diagram at http://www.tepco.co.jp/nu/fukushima-np/images/handouts_110701_02-j.pdf . At the same time, the PVC hoses will be changed to steel pipes.

 

[MiceAndMen]

Yes but this new water injection system is almost the same as concrede pump, so this shouldn't act on sst water level
interesting data and photos from today about unit 4:
http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_110630_03-e.pdf

Hallelujah we finally have an official TEPCO diagram for the refueling floor at unit 4. Very interesting pictures. How very strange to see the reactor well open to the sun and sky looking like a large swimming pool.

 

[joewein]

The CTBTO monitoring is back.

I find the I-131 peaks to be indicative of ongoing fission somewhere on the site.

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

I find they show the exact opposite.

If fresh I-131 was produced by fission and released then one would expect levels to come back to the same levels in the first chart after every fission event, more or less. The fact that both the valleys and peaks of the iodine curves drift down in line with logarithmic decay indicates that no fresh I-131 is being produced. The ups and downs are probably mostly driven by weather conditions, such as changes in wind directions, rain, etc.

The second argument against ongoing fission is that the ratio of iodine to cesium is shifting just the way one would expect from decay. Cesium has been holding almost steady (with some random ups and downs) since later March, while iodine keeps falling (also with some ups and downs). That's precisely what one would expect in the absence of ongoing fission, given the different half lives (Cs-134: 2 y; Cs-137: 30 y; I-131: 8 d). If there were fresh releases from ongoing fission, the cesium and iodine curves would look a lot more alike than they do.

 

[joewein]

Yes but this new water injection system is almost the same as concrede pump, so this shouldn't act on sst water level
interesting data and photos from today about unit 4:
http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_110630_03-e.pdf

Hallelujah we finally have an official TEPCO diagram for the refueling floor at unit 4. Very interesting pictures. How very strange to see the reactor well open to the sun and sky looking like a large swimming pool.

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.

 

[causeceleb]

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