Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[Jorge Stolfi]

And that's all, we have seen everything.

Shall we conclude that the fuel in SFP #4 is fine and dandy, no H2 was generated, and the building did not explode?

*IF* there is damaged fuel in the #4 SFP, my guess would be the last row of 3x10 racks in the back, beyond the fallen staircase. There, the outline of the racks is fuzzy; maybe damage, maybe just bad imaging...

I fancy I see another area of damage on the right side of the main group of racks, two racks above the fallen rectangular plate, to the right of the staircase and slightly closer than it.

Bubbles seem to be rising from the bottom of the tank, in the free spaces adjacent to those two areas.

Just my imagination?

I suppose that the sort of damage we are looking for would leave the ends of the assemblies reasonably intact while the rest corrodes/melts. Is that correct?

 

[~kujala~]

pdObq, it's better to look the overall trend, not some big values every here and now.
For the unit 1 it mostly makes sense until April 7th 18:00 (31,1 Sv/h), then you suddenly get these mega values after which CAMS D/W(A) stops working.
I wouldn't trust the values between April 8th 0:00 - April 8th 13:00 for the unit 1.

 

[PietKuip]

Gundersen made an update to his previous hypothesis about SFP #3.

(4) Some other people (not Gundersen himself) suggested that since plutonium melts at a higher temperature than uranium, plutonium could have accumulated in a mass at the bottom of the pool
(5) This could cause a prompt, but "moderated" criticality

Contentions 1, 2, and 3 seem correct on the basis of the evidence. New question is: do hypotheses (4) and (5) make any sense?

Previously it was hard to imagine how an explosion could compress damaged fuel rods into a configuration resulting in criticality. Is the above any more plausible? In any case, something complex must have happened inside Unit 3 to account for what is seen in the videos.

The plutonium hypothesis is just because one needs something that might sustain a chain reaction. It is hard to imagine that in old fuel. But it is even more difficult to imagine how plutonium could have purified itself under water...

A prompt criticality would more likely involve the fresh fuel that was also stored in the pond. If the boral plates desintegrated in the alkaline water of a boiling SFP, one might expect big trouble.

 

[AntonL]

I think one reason TEPCO is not so worried about the unit 3 is the CAMS readings.
On March 14th 7:00 they had quite high reading (167,0 Sv/h) but after that it has been going steadily down. On March 18th it was still 105,0 Sv/h but after a month it was only 15,8 Sv/h.

CAMS D/W(A)
March 14th 7:00 167,0 Sv/h
March 18th 11:50 105,0 Sv/h
April 18th 15,8 Sv/h

http://i.min.us/ilnMjk.pdf

On May the levels have also been going down. On May 1st it was 13,7 Sv/h and on May 9th it was 12,1 Sv/h.

CAMS D/W(A)
May 1st 5:00 13,7 Sv/h
May 9th 5:00 12,1 Sv/h

http://www.tepco.co.jp/nu/fukushima-np/f1/images/031_1F3_05090600.pdf

I think what they are more interested in each reactor is the radiation readings and only if they see both temperatures rising and radiation rising will there be a "strong" reaction but if there is only temperature rising the reaction is subtler.

Or is the contaminated water just being flushed out into the basement and groundwater and the radioactive water being replaced by fresh water in the unit thus diluting radioactivity which could explain the gradual and continues fall in D/W radioactivity

 

[pdObq]

pdObq, it's better to look the overall trend, not some big values every here and now.
For the unit 1 it mostly makes sense until April 7th 18:00 (31,1 Sv/h), then you suddenly get these mega values after which CAMS D/W(A) stops working.
I wouldn't trust the values between April 8th 0:00 - April 8th 13:00 for the unit 1.

Hmmm, the sudden high readings at 4/8 coincide with the sudden temperature rise of that N4B sensor (sorry, too lazy to put the japanese label into google translate). The other temp. sensors seem not to see that.

 

[Jorge Stolfi]

Average of 9 frames from the TEPCO video of SFP #4, manually aligned and with very low frequencies removed::

 

[~kujala~]

Or is the contaminated water just being flushed out into the basement and groundwater and the radioactive water being replaced by fresh water in the unit thus diluting radioactivity which could explain the gradual and continues fall in D/W radioactivity

The maximum from the unit 3 turbine building has been 750 mSv/h so far from the surface of the stagnant water.

Also IAES states: "In addition the water in the turbine building floor does not show high contaminations level."
http://www.slideshare.net/iaea/technical-briefing-11-0505

(I think they think 750 mSv/h is not "high". )

If water would leak wouldn't the contamination level in the turbine building be much higher?

(Of course there is a possibility of the water leaking into the basement on the reactor building and only a small part of it leaking into the basement of the turbine building. The radiation in the basement of the reactor building is still unknown.)

 

[AntonL]

Here are all the files:

http://k.min.us/ilnOrs.pdf" Water levels and pressure
http://k.min.us/ilskVG.pdf" temperature

http://k.min.us/ilrLwi.pdf" Water levels and pressure
http://k.min.us/ilrN4q.pdf" temperature

http://k.min.us/ilnMjk.pdf" Water levels and pressure
032_1F3_04181300.pdf sorry cannot find this document can you find it?
unfortunately original documents cannot be found - they have been pulled from the Tepco site, these were google cached - the net does not forget (but it forgot one)

For May you can download these values
www.tepco.co.jp/nu/fukushima-np/f1/images/0[/URL]xy_1Fx_mmdd0600.pdf

were x is 1,2,or 3
y is 1 for water levels, pressure and CAMS, 2 temperatures
mm is month ie 05
dd is day ie 09

example http://www.tepco.co.jp/nu/fukushima-np/f1/images/032_1F3_05090600.pdf
][/QUOTE]
I have found this document for a couple days later and is attached
[ATTACH=full]142709[/ATTACH]

 

[elektrownik]

I found the missing file..
http://doc-0o-94-docsviewer.googleusercontent.com/viewer/securedownload/dsn1aovipa7l846lsfcf94nedj8q2p4u/8c5thse5v9cd2meshc5cl2qr6f934scr/1304931600000/Ymw=/AGZ5hq8BgbJY1gwaOYx83cPOdNw6/QURHRUVTZ0ZFcXF2dWt0OGRCUm9ueUdCMkk3MzdTR3l5bHBxLXRCVEJXdURxYk9XeTdQcElpTldzcTdGdXdQTjAteXBxekN2TFRCWGZ1MHRVbGNWQUEzV1pvSzRRT1Fyb1I2cTNwTnZlUTkzTlh5bVVBX0NXUy03Wkc3N0NQcTZjd0RFOTBvZGFyZVc=?a=gp&filename=032_1F3.pdf&chan=EgAAAD6vI5/VRlCU5i4pgUzPU9Km4tn1JD8a0Jzc20%2BGFwbX&docid=6345a1e68d72ae09aae9bdedb1337358&sec=AHSqidaieXcDccdYhypxj0jsUp_XglLAWR4WCIYyJHrL0-F4fzZsO-yLoIuXoaM4FfNGF4VdNGO8&nonce=11ec8voqipgke&user=AGZ5hq8BgbJY1gwaOYx83cPOdNw6&hash=9bnuup18t2abh38mqss9o0iu6u9rkmq2"

 

[Rive]

Shall we conclude that the fuel in SFP #4 is fine and dandy, no H2 was generated, and the building did not explode?

Why not? It's even ready for a hot bath

What I'm telling is that there was no explosion or fire in SFP#4. That's all I'm saying

Average of 9 frames from the TEPCO video of SFP #4, manually aligned and with very low frequencies removed:

http://www.ic.unicamp.br/~stolfi/EXPORT/projects/fukushima/videos/110508_2/frames-b/avg-001--009.png

May I ask that what kind of software did you used for that? I have some more candidates for such trickery.

 

[MiceAndMen]

I agree with Fred, and fear this is, again, a matter of overparsing a translated statement.

Well I guess it could be that. I don't read Japanese.

They have also previously refused to release blueprints, because they include "the maker's [GE's] knowhow."

My reading is that TEPCO is concerned about getting into trouble for leaking documents that they had a responsibility to safeguard -- both for public safety legal reasons (protection from terrorists, for example), and for reasons of contractual obligation to GE. I don't see an implied threat to foreign bloggers, and indeed, don't see jurisdictionally how they could even make a credible one if they wanted to.

Yes, the connection to GE was discussed here previously and that could have a bearing on it, although one could make a pretty solid argument that the damage caused by the release of the drawing is immeasurably small. A desire to avoid shame could be a key factor as well.

As it turns out they had nothing to fear from terrorists that they couldn't accomplish all by themselves.

Maybe someone would be so kind as to translate this:
http://www.soumu.go.jp/menu_news/s-news/01kiban08_01000023.html
Google does an OK job, but I'd like to hear what others think.

It wouldn't take much to move "unauthorized release of nuclear blueprints" into the "illegal" category IMO, and receiving cooperation from other nations in an effort to eradicate said illegal information is probably a good bet. See the current CEO of General Electric, for example http://en.wikipedia.org/wiki/Jeffrey_R._Immelt

 

[AntonL]

TEPCO discovers NEW PHYSICS

http://www3.nhk.or.jp/daily/english/08_18.html
T

TEPCO releases footage of No.4 reactor pool
The operator of the Fukushima Daiichi nuclear power plant has released footage of the spent fuel pool in the Number 4 reactor.

The video was taken on Saturday by a camera on the tip of a mechanical arm used to pour water to cool the reactor.

The footage shows 1,535 spent fuel rods stored in racks and covered by water. It also shows debris and ladders damaged by an explosion that occurred after the March 11th earthquake and tsunami. The shelves on the side wall have been destroyed.

Bubbles are occasionally visible, as the water is boiling at a temperature of 84 degrees Celsius.

After analyzing the amount of radioactive materials in the water, Tokyo Electric Power Company has concluded that the spent fuel rods are not seriously damaged.

The Number 4 reactor was not operating at the time of the quake. The reactor building was severely damaged by a hydrogen explosion on March 15th.
Sunday, May 08, 2011 23:00 +0900 (JST)

boiling at 84^oC :

 

[whoswho69]

http://www3.nhk.or.jp/daily/english/society.html - ,,Tokyo Electric Power Company released 2 photos taken inside the No.1 reactor building early on Monday."
TEPCO says that pictures posted http://www.tepco.co.jp/en/news/110311/ are pictured on May 9th, 2011.
http://www.tepco.co.jp/en/news/110311/images/110506_Northwest_1.jpg
http://www.tepco.co.jp/en/news/110311/images/110506_North_2.jpgThe pictures name are 110506_Northwest_1.jpg and 110506_North_2.jpg. I think that pictures are made on May 6th, 2011.

 

[MiceAndMen]

Average of 9 frames from the TEPCO video of SFP #4, manually aligned and with very low frequencies removed::

The water is murky and the focus is fuzzy at that distance. Averaging 9 fuzzy frames results in another fuzzy frame, and I don't think 2D Fourier transforms help all that much unless you know the point spread function of the lens, and even then no amount of convolution filtering will extract information that isn't there to begin with. Image enhancement processing is a valid tool under the right circumstances, but this is trying to extract information from data that just isn't there IMO. For instance, we know the back rail of the stairs is there from the video after the 13 second mark, yet your processing fails to bring it into focus. I just don't see how anyone can draw any valid conclusions about the condition of fuel bundles back there.

 

[oneidak]

From The Physics arXiv Blog at MIT's Technology Review website -

(05/09/2011) Chain Reactions Reignited At Fukushima After Tsunami, Says New Study

Radioactive byproducts indicate that nuclear chain reactions must have been burning at the damaged nuclear reactors long after the disaster unfolded

http://www.technologyreview.com/blog/arxiv/26738/

The source paper is -
Matsui, T. Deciphering the measured ratios of Iodine-131 to Cesium-137 at the Fukushima reactors. arXiv:1105.0242v1.
abstract: http://arxiv.org/abs/1105.0242
full text (pdf): http://arxiv.org/PS_cache/arxiv/pdf/1105/1105.0242v1.pdf

 

[ernal_student]

A Japanese news story from 27 April says TEPCO doesn't like what Nancy has on her website.
http://www.asahi.com/english/TKY201104260122.html

Oh I expected something more sinister.

As regards the secrets of TEPCO. In my humble opinion a court should have ordered them to publish all plant layout and infrastructure plans of the affected facilities in order to allow the rest of the world to help assess the damage and work toward countermeasures.

Companies running nuclear power plants, unlike car makers, are not in a race with the competition and don't need to keep secrets. On the other hand, their special responsibility to us, the public, should be a reason for compelling them to openness. Why has the International Atomic Energy Agency not intervened?

I hope this is not altogether off topic in this forum.

 

[TCups]

The "round thing" may be an enclosure within the SFP that holds a fuel transportation cask while loading and unloading. That would be another version of the square concrete enclosure visible in the far left corner of the SFP in the photo of an unidentified japanese reactor (Unit #5?) attached.

Some blueprints/drawings (said to fit Unit #1) show a separate "cask-loading pool" between the equipment pool and the elevator shaft. Presumably in Units #2--#4 that separate pool was replaced by a smaller enclosure within the SFP.

Nope. The accessory pool inside a corner of the main pool is a feature at Dianni, but not at Daiichi. The Daiichi 2, 3, 4 plans have a "cask lay down pool" between the vertical lift shaft and the main SFP, pretty sure.

As for debris in the pools, differential pressure of the blast was outward and upward, so most of the debris was vectored away from the pools. Unit 4's roof was intact when debris from 1 and 3 were salted over the NPP site. At Unit 3, SFP3 does seem to have at least part of the FHM or some similar large green piece of equipment in the pool. I am as yet not totally convinced that all of the FHM is in the pool, but clearly the vector of the force of the explosion was upward, out of the SFP3.

At Unit 4, clearly a large, intact portion of the roof slab has done much of the damage at the north end of the building. It follows, by analogy, that part of the roof slab may have done damage at Unit 3, but, first, the explosion was probably much more powerfue (at least the vertical (steam?) explosion over SFP3) and, second, large pieces of debris can be seen lofted skyward then falling on the building, perhaps even part of the FHM. Put that in the "unresolved" column along with a bunch of other stuff.

Unit 4 is and has been the enigma as far as explosions. In my lay opinion, Anton's suggestion of low water, but not exposed fuel, and radiolysis occurring in vigorously boiling water would help explain some of the discrepancies. Vigorous boiling at SFP4 versus superheating water in lower thermoclines of the SFP3 prior to an explosion out of the primary containment of Unit 3 might also explain the qualitative difference in the "hydrogen" explosions at these units. Alas, "unresolved".

As it now seems to be "official" that the primary containment of Unit 3 has an enlarging crack, my logic tells me the most obvious site would be at or around the fuel transfer chute. That is yet another "unresolved" awaiting confirmation.

 

[MiceAndMen]

Oh I expected something more sinister.

No, nothing so dramatic. Still, hers is the only website I have seen mentioned by name in any of the Japanese media coverage.

As for intervention by outsiders, I think everyone around the world wants the whole mess to just go away. As long as TEPCO seems to be making progress they will be allowed to run the show barring any more dramatic unplanned events. Nobody else seems to have any better ideas at the moment.

 

[GJBRKS]

Ooohh ! I like it how they translated 'flange' mucho - mas ! ! :)

Nice images of temperature graphs and temperature sensor locations
[PLAIN]http://k.min.us/in4JQ0.JPG

Ooohh ! I like it how they translated 'flange' mucho - mas ! ! :)

 

[jlduh]

High levels of Strontium 89 and 90 found in soil around Daichi reactors:

http://www3.nhk.or.jp/daily/english/09_01.html

Up to 570 becquerels of strontium 90 per kilogram of dry soil were detected in samples from 3 locations. They were taken on April 18, about 500 meters from the Number 1 and 2 reactors at soil depths of up to 5 centimeters. The amount detected is about 130 times higher than a previous high, level that was measured in Fukushima Prefecture before the accident at the nuclear plant.

TEPCO also said it found 4,400 becquerels of radioactive strontium 89 per kilogram of dry soil taken from the same location.

Earlier in March, strontium was detected in soil and plants outside the 30-kilometer zone around the Fukushima plant.

Note this also:

Strontium can cause cancer and like calcium it tends to collect in bones once humans inhale it.

To the isotopes specialists: does these levels of strontium tells something about the cores destructions or possible criticalities? What are the most possible ways this strontium went there? By dust and particulates during the explosions? By steam?

 

[TCups]

TEPCO discovers NEW PHYSICS

http://www3.nhk.or.jp/daily/english/08_18.html
T

boiling at 84^oC :

Obviously very low atmospheric pressure at sea level in Japan. . . With the barometer that low, now we have to worry about the big storm that is coming.

 

[MiceAndMen]

Nope. The accessory pool inside a corner of the main pool is a feature at Dianni, but not at Daiichi. The Daiichi 2, 3, 4 plans have a "cask lay down pool" between the vertical lift shaft and the main SFP, pretty sure.

And I'm pretty sure no evidence for any such separate cask laydown pool has been presented here or anywhere else.

 

[SteveElbows]

Seems they detected radiation levels of up to 700 millisieverts at one point when humans entered reactor 1 building earlier today, although it was much lower at other places in the building:

http://english.kyodonews.jp/news/2011/05/89922.html

 

[biffvernon]

I don't know enough about geology to draw any qualified conclusions, but probably mudstone should be considered more stone than mud. Does anyone know how much that weakens if it soaks up enough water? And how much would be enough water?

I don't know what Japanese word got translated into 'mudstone' but the English word used by geologists usually describes a stone that hasn't been mud for maybe hundreds of millions of years. Very much stone and not mud and unlikely to change strength if wet.

There was a video, linked to a few thousand posts ago, of a couple of people who drove into the evacuation zone early on. Their car stopped perhaps a kilometre short of the plant when the road became impassable. One shot showed they guy stepping up a vertical displacement of maybe 50-70cm in the roadway. It's not inconceivable that the earthquake caused some substantial movements in the bedrock under the power station.

 

[Astronuc]

As regards the secrets of TEPCO. In my humble opinion a court should have ordered them to publish all plant layout and infrastructure plans of the affected facilities in order to allow the rest of the world to help assess the damage and work toward countermeasures.

Companies running nuclear power plants, unlike car makers, are not in a race with the competition and don't need to keep secrets. On the other hand, their special responsibility to us, the public, should be a reason for compelling them to openness. Why has the International Atomic Energy Agency not intervened?

Actually, utilities use the technology of others - like GEH, Toshiba, Westinghouse - and they are obliged to keep proprietary (trade secret) information private - between themselves and the supplier/vendor. The government is allowed to review the proprietary information.

When technical documents are provided to the government, there is usually a proprietary version (not for public disclosure) and a non-proprietary version (for public disclosure). In the non-proprietary version, most of the key data and details are blanked out.

Since 2001, much of the design details of the plants has been classified as 'not for public disclosure'. This is not so much to hide information from the public, but to keep details out of the hands of those who would seek to damage the facility. One could in theory make a request to visit the government or corporate offices and review the details, but one would not get to keep a copy of any drawing, which has not been released. Of course, one would have to have a legitimate reason to have access to the information.

 

[jlduh]

From The Physics arXiv Blog at MIT's Technology Review website -

(05/09/2011) Chain Reactions Reignited At Fukushima After Tsunami, Says New Study

Radioactive byproducts indicate that nuclear chain reactions must have been burning at the damaged nuclear reactors long after the disaster unfolded

http://www.technologyreview.com/blog/arxiv/26738/

The source paper is -
Matsui, T. Deciphering the measured ratios of Iodine-131 to Cesium-137 at the Fukushima reactors. arXiv:1105.0242v1.
abstract: http://arxiv.org/abs/1105.0242
full text (pdf): http://arxiv.org/PS_cache/arxiv/pdf/1105/1105.0242v1.pdf

This part of the article is most interesting; they are also suspecting criticalities at N°2 and in the SFP of N°4... even if some more data are needed to confirm this!

"The data of the water samples from the unit-4 cooling pool and from the sub-drain near the unit-2 reactor show anomaly which may indicate, if they are correct, that some of these fission products were produced by chain nuclear reactions reignited after the earthquake," he says.

These chain reactions must have occurred a significant time after the accident. "It would be difficult to understand the observed anomaly near the unit-2 reactor without assuming that a significant amount of fission products were produced at least 10 - 15 days after X-day," says Matsui.

So things in reactor 2 must have been extremely dangerous right up to the end of March.

Matsui points out that there are some potential question marks about the data. One possibility is that the chemical properties of cesium and iodine might mean they are flushed away from the reactors at different rates, changing their ratios.

But it's hard to see what chemical processes could be responsible for this and even harder to understand why they would occur in some places but not others at Fukushima.

 

[jlduh]

I don't know what Japanese word got translated into 'mudstone' but the English word used by geologists usually describes a stone that hasn't been mud for maybe hundreds of millions of years. Very much stone and not mud and unlikely to change strength if wet.

There was a video, linked to a few thousand posts ago, of a couple of people who drove into the evacuation zone early on. Their car stopped perhaps a kilometre short of the plant when the road became impassable. One shot showed they guy stepping up a vertical displacement of maybe 50-70cm in the roadway. It's not inconceivable that the earthquake caused some substantial movements in the bedrock under the power station.

I found an article (japanese) whose translation is not very clear but talks about the way this plant was built and founded in mudstone. The (bad) translation is here:

http://webcache.googleusercontent.com/search?q=cache:gb_xkkHNfpsJ:ziphilia.net/bbs.cgi/economy/1304793715/+mudstone+fukushima&cd=2&hl=en&ct=clnk&source=www.google.com

The link to the japanese version is this one (for those who read japanese and maybe could clarify what is said?):

http://ziphilia.net/bbs.cgi/economy/1304793715/

 

[coolin'_down]

Yes, this sounds odd. But hydrazine is used to prevent corrosion of steel parts in steam circuits - it removes oxygen molecules. Concentrations are very low, less than 1 ppm.

Even stranger: vitamin C is recommended as a substitute!
http://pubs.rsc.org/en/Content/Database/HAZ1307001305

About the only good thing you can say about hydrazine is that it's not radioactive. Some formulations are incredibly toxic. One good whiff and your liver is history.

Thank you for input. So it's a highly toxic substance, but is it normally used in nuclear power plants?

 

[Dmytry]

High levels of Strontium 89 and 90 found in soil around Daichi reactors:

http://www3.nhk.or.jp/daily/english/09_01.html
Note this also:To the isotopes specialists: does these levels of strontium tells something about the cores destructions or possible criticalities? What are the most possible ways this strontium went there? By dust and particulates during the explosions? By steam?

afaik you need quite high temperatures to get strontium out of the fuel. The ratios of sr-90 to cs-137 to transuranics could be of interest, as indicator for the fuel temperature. Transuranics to control for the dust.

BTW, the % fuel damage talk... human thought has this amazing ability to make abstractions to the point where they lose meaning. There is a % of the rods that ruptured, there is a % of the fuel pellets that disintegrated into dust, there's % of the fuel pellets that reached this temperature, there's % of fuel pellets that reached that temperature, there's % of the fuel pellets that melted, etc. There's % of radioactive noble gasses that escaped, % of iodine, of cs-137, of sr-90, etc. All different %.
But there is no single fuel damage % that you can magically obtain by measuring radiation in the drywell.

 

[jensjakob]

Discovery has released a documentary, some of it can be seen here:
http://ing.dk/artikel/118964-foelg-med-brandmaendene-ind-paa-fukushima-vaerket

 

[clancy688]

Or is the contaminated water just being flushed out into the basement and groundwater and the radioactive water being replaced by fresh water in the unit thus diluting radioactivity which could explain the gradual and continues fall in D/W radioactivity

Highest CAMS readings for Unit 3 D/W on 3/14... that's when the explosion happened in Unit 3. There was a speculation regarding this explosion by TCups. I'd love to hear his comments on this, because I'm not sure if the speculations I'll citing are still up to date... ^^;

So if I remember correctly, he assumed that the explosion could have happened inside the containment and below the SFP. The resulting shock- and heatwave would then pierce the SFP, boil the water away and wreck havoc on everything inside the pool.
If that's what really happened in Unit 3 - wouldn't it be possible that leftover fuel debris is flowing back through the crack in the bottom INSIDE the containment? Then the high radiation readings wouldn't belong to molten core fuel, but to pulverized spent fool.
Which's washed out during the water spraying and pumping activities over the next weeks.

As stated above - TCups, I'd love to hear your opinion about this.

 

[Borek]

Thank you for input. So it's a highly toxic substance, but is it normally used in nuclear power plants?

I don't know if it is "normally used in nuclear plants" but its use for corrosion prevention is nothing new.

 

[TCups]

Highest CAMS readings for Unit 3 D/W on 3/14... that's when the explosion happened in Unit 3. There was a speculation regarding this explosion by TCups. I'd love to hear his comments on this, because I'm not sure if the speculations I'll citing are still up to date... ^^;

So if I remember correctly, he assumed that the explosion could have happened inside the containment and below the SFP. The resulting shock- and heatwave would then pierce the SFP, boil the water away and wreck havoc on everything inside the pool.
If that's what really happened in Unit 4 - wouldn't it be possible that leftover fuel debris is flowing back through the crack in the bottom INSIDE the containment? Then the high radiation readings wouldn't belong to molten core fuel, but to pulverized spent fool.
Which's washed out during the water spraying and pumping activities over the next weeks.

As stated above - TCups, I'd love to hear your opinion about this.

@Clancy688

Regarding Unit 4, the reactor and reactor vessel were cold, with no fuel loaded. The explosion at 4 had to be "fueled" by the contents of the SFP if it was indeed a hydrogen explosion. Some say H2 from uncovered fuel with hot zirconium + steam => hydrogen release. Anton suggests (credibly, I think) that radiolysis of H2O in boiling water could release sufficient H2 to have caused the explosion. Other possibilities have not been excluded with certainty, but seem less likely.

Regarding Unit 3, it's a different story. To me, the images and information available at the time suggested an explosion had come from the upper primary containment, sideways through the fuel transfer chute and into the upper portion of the SFP3 with a subsequent secondary explosion of leaked hydrogen in the upper floor, with vaporization and steam explosion rising vertically from the SFP.

The audio evidence has not been authenticated, but also suggests a complex occurrence at Unit 3 with 3 loud booms (or echoes, or a completely bogus soundtrack added by video editors -- take your pick).

This is all unconfirmed speculation on my part, but again, what I have read and learned suggest it is at least plausible.

Disclaimer: Please understand, I am neither an industry expert nor a nuclear engineer of any sort -- I am a radiologist by trade. My speculation and opinion are backed only by my personal visual interpretation of the evidence. The theory is at least partly in variance with pressure readings in the lower primary containment that have since been posted, if my understanding of those numbers are correct. It is, however, concordant with recently released assessments of a "crack" in the primary containment of Unit 3, I believe. Sorry, time doesn't permit me to run down the posted reference to the "crack" -- perhaps someone might verify and/or clarify this.

Addendum: Regarding the crack in the primary containment, Unit 3, see StrangeBeauty's post at #6089 with references:

https://www.physicsforums.com/showpost.php?p=3288229&postcount=6089

 

[clancy688]

Regarding Unit 4, the reactor and reactor vessel were cold, with no fuel loaded. The explosion at 4 had to be "fueled" by the contents of the SFP if it was indeed a hydrogen explosion.

Sorry. I meant Unit 3. Typo, will be fixed.

The audio evidence has not been authenticated, but also suggests a complex occurrence at Unit 3 with 3 loud booms (or echoes, or a completely bogus soundtrack added by video editors -- take your pick).

I'd say bogus soundtrack. I found a german news program from 3/14 and there they show the explosion - but you only hear helicopter noises, NO explosions.

http://www.tagesschau.de/multimedia/sendung/ts25382.html (@ 00:40, don't know if it's available in other countries)

 

[TCups]

Sorry. I meant Unit 3. Typo, will be fixed.



I'd say bogus soundtrack. I found a german news program from 3/14 and there they show the explosion - but you only hear helicopter noises, NO explosions.

http://www.tagesschau.de/multimedia/sendung/ts25382.html (@ 00:40, don't know if it's available in other countries)

Helicopter noises? Your ears are better than mine.

 

[clancy688]

Helicopter noises? Your ears are better than mine.

I'm still in my early twenties... It's hard to describe... something like a constant "whoosh" in the background. Similar to the noise in this video: (But not as loud)

 

[TCups]

I'm still in my early twenties...


It's hard to describe... something like a constant "whoosh" in the background. Similar to the noise in this video: (But not as loud)

Being much older, I was listening mostly to the attractive "newsfrau" and her lovely German voice.

 

[~kujala~]

As everybody knows, TEPCO calculates core damage ratio combining "Core damage ratio (drywell)" (CAMS drywell) and "Core damage ratio (wetwell)" (CAMS wetwell). The actual percentages come directly from the charts. Even without CAMS wetwell you could still get some kind of estimate using CAMS drywell only.

For instance after corrections for Unit 1 we got 45 % (drywell) + 10 % (wetwell) = 55 % together, which is TEPCO's current estimate for the core damage in unit 1. (Perhaps this value doesn't mean anything, though, see the post above by Dmytry).

http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110427e18.pdf

Well the strange thing I noticed that CAMS drywell for unit 3 doesn't appear to be in the charts AntonL posted. Unit 1 and unit 2 CAMS drywell can be found from the charts but Unit 3 measurement is made on March 14th, 4:20 am. In AntonL's charts the nearest ones are March 14th, 4:00 am and March 14th, 4:30 am, neither of them has a CAMS drywell -reading.

I don't know where the 140 Sv/h for unit 3 CAMS drywell has come from, perhaps they made an additional measurement which cannot be found in the AntonL's charts? It's still quite close to the nearest one, March 14th 5:00 am 158 Sv/h.
http://i.min.us/ilnMjk.pdf

 

[AntonL]

Here are all the files:

http://k.min.us/ilnOrs.pdf" Water levels and pressure
http://k.min.us/ilskVG.pdf" temperature

http://k.min.us/ilrLwi.pdf" Water levels and pressure
http://k.min.us/ilrN4q.pdf" temperature

http://k.min.us/ilnMjk.pdf" Water levels and pressure
032_1F3_04181300.pdf sorry cannot find this document can you find it?
unfortunately original documents cannot be found - they have been pulled from the Tepco site, these were google cached - the net does not forget (but it forgot one)

For May you can download these values
www.tepco.co.jp/nu/fukushima-np/f1/images/0[/URL]xy_1Fx_mmdd0600.pdf

were x is 1,2,or 3
y is 1 for water levels, pressure and CAMS, 2 temperatures
mm is month ie 05
dd is day ie 09
][/QUOTE]

[quote="elektrownik, post: 3291239"]OMFG did you saw CAMS data 3/14 for unit 3 ? It is error or 100% of unit 1 core is damaged[/QUOTE]

elektrownik comment made me study the other files in detail and I plotted D/W CAMS data over the time period provided (Sv/h vs date)
[ATTACH=full]142711[/ATTACH]
[ATTACH=full]142712[/ATTACH]
[ATTACH=full]142713[/ATTACH]

Now note that spike in Unit 1, and Tepco refrained from publishing any more D/W CAMS data after that event, their reports mention that the unit 1 D/W Cams is out of order, both of them the A and B channels

But are they out of order? or is there something happening in the reactor that we are not supposed to know or deduce from their data, now look at the temperature plot, on the same day 8th April there was a sudden spike coinciding with the spike of the CAMS data

I leave it for the experts to comment, was there a sudden small sub-critical event on the 8th April?
csv
[PLAIN][PLAIN]http://k.min.us/in4JQ0.JPG

PS. If you think I copied lots of data by hand think again, these files can also be found as .csv files making data manipulation quite easy

 

[ascot317]

Sorry. I meant Unit 3. Typo, will be fixed.



I'd say bogus soundtrack. I found a german news program from 3/14 and there they show the explosion - but you only hear helicopter noises, NO explosions.

http://www.tagesschau.de/multimedia/sendung/ts25382.html (@ 00:40, don't know if it's available in other countries)

The soundtrack doesn't have to come from the same source as the video. Could have been recorded by someone else at a different location.

 

[rowmag]

Maybe someone would be so kind as to translate this:
http://www.soumu.go.jp/menu_news/s-news/01kiban08_01000023.html
Google does an OK job, but I'd like to hear what others think.

It wouldn't take much to move "unauthorized release of nuclear blueprints" into the "illegal" category IMO, and receiving cooperation from other nations in an effort to eradicate said illegal information is probably a good bet. See the current CEO of General Electric, for example http://en.wikipedia.org/wiki/Jeffrey_R._Immelt

Replied over here: https://www.physicsforums.com/showpost.php?p=3291626&postcount=135

 

[clancy688]

The soundtrack doesn't have to come from the same source as the video. Could have been recorded by someone else at a different location.

Yeah, of course.

I think it's plausible that some tv producer added three loud booms to an otherwise "silent" video of a major explosion in a NPP. That helps to spice things up a bit, to "entertain" viewers so that they'll watch again next time.
Or just to make his own video stand out so that it's getting bought by foreign tv stations.
As I said, for me, that's very plausible.

But it's highly implausible that the same tv producer would add helicopter noise to an explosion video. Think about it, why should he do that? It doesn't spice up anything. Moreover, why should he replace three booms (if those are the real deal and were in fact recorded parallel to the video track) with boring helicopter noise? There is no logic in that.

So I'm guessing that the three booms are just ear candy, and that the "helicopter noise vid" from tagesschau is the real deal.

 

[biffvernon]

With hills in-land from the camera position it would be surprising if one did not hear an echo or two of the initial boom.

 

[Jorge Stolfi]

The water is murky and the focus is fuzzy at that distance.

Nitpicking: true for murkiness, but the focus should be OK.

Averaging 9 fuzzy frames results in another fuzzy frame, and I don't think 2D Fourier transforms help all that much unless you know the point spread function of the lens, and even then no amount of convolution filtering will extract information that isn't there to begin with. Image enhancement processing is a valid tool under the right circumstances, but this is trying to extract information from data that just isn't there IMO.

IMO too. (Rats, why do they use a video camera instead of a high-resolution photo camera? Or is just the publicly released videos that are crappy?)

However averaging N frames does remove some of the MPEG blocking artifacts and reduces the quantization noise, so you can usefully do contrast stretching and highpass filering (which are useless in the raw video frames).

For instance, we know the back rail of the stairs is there from the video after the 13 second mark, yet your processing fails to bring it into focus.

The back rail is dim but focused in the average pic.

I just don't see how anyone can draw any valid conclusions about the condition of fuel bundles back there.

What I'm telling is that there was no explosion or fire in SFP#4.

I am not drawing any conclusions. Just pointing out that we cannot tell yet whether there was any damage or not.

May I ask that what kind of software did you used for that? I have some more candidates for such trickery.

Note that this trick only works if (a) the position of the camera is fixed, only its direction and zoom changes; or (b) the object of interest is nearly flat. Otherwise there is no simple transformation that will align one image with the other. Here we had a bit of both.

There is software out there that will do this trick automatically; it is used to assemble panoramic photos from a series of ordinary snapshots (my cellphone does that).

I used a more primitive approach (more work, less accuracy) that requires finding 4 coplanar reference points in each frame by hand. In case you are interested, the recipe is in
http://www.ic.unicamp.br/~stolfi/EXPORT/projects/fukushima/videos/110508_2/00-Notebook.txt
I will try to post the source code of the two C programs I used used for perspective remapping (pnmprojmap) and Fourier filering (pnmfftfilter). But you will probably find better tools somewhere else.

 

[I_P]

Yeah, of course.

I think it's plausible that some tv producer added three loud booms to an otherwise "silent" video of a major explosion in a NPP. That helps to spice things up a bit, to "entertain" viewers so that they'll watch again next time.
Or just to make his own video stand out so that it's getting bought by foreign tv stations.
As I said, for me, that's very plausible.

But it's highly implausible that the same tv producer would add helicopter noise to an explosion video. Think about it, why should he do that? It doesn't spice up anything. Moreover, why should he replace three booms (if those are the real deal and were in fact recorded parallel to the video track) with boring helicopter noise? There is no logic in that.

So I'm guessing that the three booms are just ear candy, and that the "helicopter noise vid" from tagesschau is the real deal.

As the sound would have reached the recording unit sometime after the explosions it is also entirely plausible that the audio and video tracks were reordered for presentation to synchronize the sound with the video. By all accounts the sounds of the explosion were very loud and heard at least "40 km away". It is very likely that the camera was kept recording for sometime after the blast and would have recorded the sounds of the explosion. No need to assume that some random explosion sound was added.

 

[TCups]

Yeah, of course.

I think it's plausible that some tv producer added three loud booms to an otherwise "silent" video of a major explosion in a NPP. That helps to spice things up a bit, to "entertain" viewers so that they'll watch again next time.
Or just to make his own video stand out so that it's getting bought by foreign tv stations.
As I said, for me, that's very plausible.

But it's highly implausible that the same tv producer would add helicopter noise to an explosion video. Think about it, why should he do that? It doesn't spice up anything. Moreover, why should he replace three booms (if those are the real deal and were in fact recorded parallel to the video track) with boring helicopter noise? There is no logic in that.

So I'm guessing that the three booms are just ear candy, and that the "helicopter noise vid" from tagesschau is the real deal.

IMO, the original 3-boom audio is authentic, based on the analysis of the sound track and video. I can't imagine why anyone wanting to add ear-candy would choose a 3-boom audio with a lot of additional transient mechanical noises rather than a simple "boom". On occasion, it appears that the live video cam that likely recorded the event also records live bird songs. But das mach nichts, IMO. Not worth re-opening debate. Neither an authentic nor unauthentic sound track alters the principal theory of the explosion at Unit 3.

 

[artax]

There's some more image analysis here,... from a while back but might be interesting to compare their evaluation of the data.

http://www.poudreinternetservice.com/photographs.html

 

[Rive]

There is software out there that will do this trick automatically; it is used to assemble panoramic photos from a series of ordinary snapshots (my cellphone does that).

Thanks, but I'm a bit ahead - I've found an astronomic one: http://www.astronomie.be/registax/index.html"

With some limitations it works fine.

Ps.: yeah, I'm still just practising...

 

[zapperzero]

Areva

And now for something completely different: it is AREVA that supplied the MOX. I have not seen this stated here before.

http://dcbureau.org/201103151304/Natural-Resources-News-Service/is-airborne-plutonium-a-threat-from-reactor-number-three.html

Explains the deep involvement of the French gov't, regulators and AREVA itself in the matter at hand.

 

[etudiant]

And now for something completely different: it is AREVA that supplied the MOX. I have not seen this stated here before.

http://dcbureau.org/201103151304/Natural-Resources-News-Service/is-airborne-plutonium-a-threat-from-reactor-number-three.html

Explains the deep involvement of the French gov't, regulators and AREVA itself in the matter at hand.

Speaking of Areva, are they not due to have a 1200 ton/day water decontamination plant eunning on site by the end of May?
Has there been any evidence that work on this facility is even begun?

It is very frustrating to see a multi front problem attacked so very serially. It suggests that the strategy is to wait for natural decay to ease the problem.
However, the radioactivity measured at the various inland sewage treatment plants suggests the site is gradually worsening the local contamination.
So there is a tradeoff, delay means more lost land.