Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[jim hardy]

"""at which point the zircalloy has probably been corroded and so the core collapses. """
...or turns into a crumbly pile with shape resembling a reactor. Remember Arnie's blowtorch on the zirconium tube, he had to hit his oxygen handle to melt it. What he didnt melt he crumbled away with his fingers.

 

[ascot317]

IMO, either or both would qualify as "cracks" given the escaping steam which has to be originating from the primary containment.
.

Or could be leaking water from the SFP that is getting boiled off of the containment cap.

 

[MiceAndMen]

Page 6 of this:

http://www.slideshare.net/iaea/technical-briefing-11-0505

In the containment integrity row and the observation column, the last point thing it says is:

'Images of Unit 3 show crack in the primary containment and steam released from the reactor building.'

The lack of detail is what has caused me to have room to wonder whether the images I just mentioned could be what they refer to, or whether I am looking at the right part of the building at all. For now I'd say the footage I refer to is a potential candidate, but I would welcome lots more opinion on this matter.

My bad, I did download that document but hadn't gotten around to reading it yet.

The NYT had an online article on 25 March that said the same thing. They later changed the story to remove the part about the cracked reactor. Here's the story as it appears today: http://www.nytimes.com/2011/03/26/world/asia/26japan.html

Before they changed it, the story got picked up by other news agencies and you can still find the unaltered versions on the web, such as this one from NDTV:http://www.ndtv.com/article/world/j..._campaign=Feed:+ndtv/TqgX+(NDTV+News+-+World)

Part of the text they removed reads as follows:

A senior nuclear executive who insisted on anonymity but has broad contacts in Japan said that there was a long vertical crack running down the side of the reactor vessel itself. The crack runs down below the water level in the reactor and has been leaking fluids and gases, he said.

The severity of the radiation burns to the injured workers is consistent with contamination by water that had been in contact with damaged fuel rods, the executive said.

“There is a definite, definite crack in the vessel — it’s up and down and it’s large,” he said. “The problem with cracks is they do not get smaller.”

To be fair, however, in the original story when the "senior nuclear executive" says the "reactor vessel" is cracked he must have been referring to the primary containment shell because nobody has laid eyes (or a camera) on the actual pressure vessel since the accident. At least not that I know of. On the other hand, he says the crack "runs down below the water level" and the drywell containment vessel normally doesn't have a water level. There it seems he must be talking about the RPV itself. So maybe the NYT had some doubt about what he was saying. On the other hand, maybe he was exactly right and the original story was correct and they censored that part for reasons unknown.

 

[ascot317]

Thank you Steve you posted while i was typing.

i have not ruled out a neutron boost for that explosion for exact same reason as you. Something looked wrong. But i expect to find just the bolts stetched and it's still in place.

'...cold reason will prevail. ' A lincoln

There was likely a gamma burst during/after the explosion of #3, since Tepco has talked about 12x normal radiation peak in the control bunker.

 

[SteveElbows]

Part of the text they removed reads as follows:

To be fair, however, in the original story when the "senior nuclear executive" says the "reactor vessel" is cracked he must have been referring to the primary containment shell because nobody has laid eyes (or a camera) on the actual pressure vessel since the accident. At least not that I know of. On the other hand, he says the crack "runs down below the water level" and the drywell containment vessel normally doesn't have a water level. There it seems he must be talking about the RPV itself. So maybe the NYT had some doubt about what he was saying. On the other hand, maybe he was exactly right and the original story was correct and they censored that part for reasons unknown.

Ah yes I remember seeing that at the time, but had since forgotten all about it. I suppose my main beef with the original wording is that the word containment is not used, leaving some ambiguity about exactly what he is talking about, just as you suggest.

 

[TCups]

Part of the text they removed reads as follows:

To be fair, however, in the original story when the "senior nuclear executive" says the "reactor vessel" is cracked he must have been referring to the primary containment shell because nobody has laid eyes (or a camera) on the actual pressure vessel since the accident. At least not that I know of. On the other hand, he says the crack "runs down below the water level" and the drywell containment vessel normally doesn't have a water level. There it seems he must be talking about the RPV itself. So maybe the NYT had some doubt about what he was saying. On the other hand, maybe he was exactly right and the original story was correct and they censored that part for reasons unknown.

Or, perhaps, the "crack" was in the primary containment and the water level referred to the water level in the SFP. I seem to recall concern that a crack might be causing water leakage from the SFP (but was that at SFP4?).

 

[Jorge Stolfi]

The steam is coming from the "north" gate area of the equipment pool (yes, there is a gate on that end too).

Maybe I am using the wrong names. The steam-dryer storage pool is the narrower pool on the north side of the reactor, opposie to the spent-fuel pool. Its north end is flush (or almost flush) against the north outer wall of the building. AFAIK it has only one gate, on the south side, leading to the reactor pool (which I have been calling "refueling pool" but perhaps that is the wrong name).

To the best of my knowledge, that photo you posted was taken from the north side of the building, looking south into the south end of the steam-dryer pool.

For clarity, two files are added -- both technical drawings

Thanks! Indeed they do not seem to match F-I #3 and #4. The steam-dryer pool is rotated 90 degrees, as you say. Also I have yet to see where the cask-loading enclosure is located inside the spent-fuel pool of #4; but there have been claims that it is flush against the NW corner, and not centered on the W side as your blueprint shows.

 

[SteveElbows]

Addendum:

For clarity, two files are added -- both technical drawings. The first screenshot is my "alteration" of the original to show the equipment pool re-oriented 90 deg on its long axis and with color emphasis -- blue for the pools and red for the gates. The original document is also included. Sorry, I don't remember the original source for the technical drawings. Clearly they are just a bit different from Unit 3, but I suspect they are very close.

Thanks for your thoughts on this, they match my understanding of the layout. The diagrams you linked to may be Oyster Creek ones, as I've spent a while looking at those in the past and their D/S pool was indeed oriented differently to what we know of Fukushima's.

 

[SteveElbows]

Maybe I am using the wrong names. The steam-dryer storage pool is the narrower pool on the north side of the reactor, opposie to the spent-fuel pool. Its north end is flush (or almost flush) against the north outer wall of the building. AFAIK it has only one gate, on the south side, leading to the reactor pool (which I have been calling "refueling pool" but perhaps that is the wrong name).

To the best of my knowledge, that photo you posted was taken from the north side of the building, looking south into the south end of the steam-dryer pool.

I think it was a case of them using a description that was open to this misunderstanding. They meant north gate as in north of the reactor, not north of the dryer pool.

 

[SteveElbows]

Here is a much simplified diagram which features the gate we are talking about, courtesy of a 2007 earthquake incident that caused pool spills:

http://www.tepco.co.jp/en/niigata/plant/jisho02-e.html

 

[ihatelies]

I've lurked here from the beginning of Fukushima.

I've posted on a few other forums, been kicked off one, and been universally shouted down at Blue Marble on their similar thread, and on a couple other forums. It may happen here too.

So I will make my claim and back it up with Facts and leave it at that.

I believe that the #3 reactor did indeed blow it's top on March 14th. I see in these latest posts someone says that idea was shot down in March. I can find a lot of people trying to shoot it down. I can find no evidence where it's been shot down. If someone here can negate it, that makes me happy, as I've been very worried about it for two months.

I will provide two initial pictures which, along with the "collage" described above, will give you a pretty good visual that something large and round was ejected through the roof of Reactor 3 building.

I have gotten most of these photos from Nancy's site - which is excellent, and I see she is posting here.

The first picture is taken from above Reactor 4 toward reactor #3. What you will see is the wreckage of the roof laying over the building as it has for awhile. You can see the spent fuel pool with some steam or mist above it. In the roof beams, you can see an unmistakable large round hole that has been formed in a couple of large steel beams.

But the hole is in the wrong place, you say?

Nope, that hole was previously excactly above the reactor core. Now take a look at the second picture I show, which is a view of the same wreckage looking from west to east.

You can clearly see the roof beams laying across the wreckage. Look to the far left and you see a couple of wall beams still attached at the bottom and to the roof structure, but laying at an angle over the wreckage. When you spot them, you can see that the entire roof beam structure shifted to the south when it fell back down.

If you shift the whole structure back to the left in picture #2 then it puts the big round hole precisely over the reactor core from picture #1.

I believe that not only did the top of the reactor blow, but possibly the entire RPV ejected and landed in a few places around the plant, but a bunch of it landed on the north end of the wreckage of reactor #3.

For any of you that have been following me elsewhere, I've got a ton of supporting evidence, but I'll leave it at that now...

 

[Dmytry]

Well in order to melt either the Boral metal or the Boraflex plastic, the fuel would have to be not under water. Then it could melt, if the water were gone.

But without water it can't go critical. It'd have to get covered with water again to go critical and they weren't adding water to pools yet on day of explosion - it's reported to have started days later. They were still adding seawater to reactors.

so that's the catch-22 I'm in on pool criticality.

are you sure water level would be dynamically stable? Suppose there is a small wave, that hits the hot zirconium here, and boils off, and that may amplify the wave. Without fluid simulation you simply can't tell. Plus there was a plenty of aftershocks.

It is a fact that both boral and boraflex have lower melting point than the temperature at which fuel rods start making a lot of hydrogen.

 

[clancy688]

For any of you that have been following me elsewhere, I've got a ton of supporting evidence, but I'll leave it at that now...

Well, on http://cryptome.org/eyeball/daiichi-npp/pict7a.jpg" picture you can see right through the rest of the damaged roof beams directly on the upper deck of the reactor.
Remarkebly, the deck is okay. In case the reactor went airborne, you'd at least suspect a big hole in the middle where the reactor lies. Not a smooth surface.

Moreover, I'd like to see the explosion which totally disintegrates the upper part of the RPV but otherwise only destroys the top of the building. If the upper part of the RPV really got ejected, we'd see it lying around on sat images. AND we'd see the bright, yellow containment cap somewhere in the vicinity. I think those things are in easily spottable colours for a reason.

 

[sp2]

Many thanks.

This one: "[URL
[/URL] is a turbine building with a blowout panel removed?


Oooops! http://www.tepco.co.jp/en/news/110311/images/110510_1.zip"

OMG. That looks just a *little* bit different than SFP 4, doesn't it.

 

[TCups]

I've lurked here from the beginning of Fukushima.

I've posted on a few other forums, been kicked off one, and been universally shouted down at Blue Marble on their similar thread, and on a couple other forums. It may happen here too.

So I will make my claim and back it up with Facts and leave it at that.

I believe that the #3 reactor did indeed blow it's top on March 14th. I see in these latest posts someone says that idea was shot down in March. I can find a lot of people trying to shoot it down. I can find no evidence where it's been shot down. If someone here can negate it, that makes me happy, as I've been very worried about it for two months.

I will provide two initial pictures which, along with the "collage" described above, will give you a pretty good visual that something large and round was ejected through the roof of Reactor 3 building.

I have gotten most of these photos from Nancy's site - which is excellent, and I see she is posting here.

The first picture is taken from above Reactor 4 toward reactor #3. What you will see is the wreckage of the roof laying over the building as it has for awhile. You can see the spent fuel pool with some steam or mist above it. In the roof beams, you can see an unmistakable large round hole that has been formed in a couple of large steel beams.

But the hole is in the wrong place, you say?

Nope, that hole was previously excactly above the reactor core. Now take a look at the second picture I show, which is a view of the same wreckage looking from west to east.

You can clearly see the roof beams laying across the wreckage. Look to the far left and you see a couple of wall beams still attached at the bottom and to the roof structure, but laying at an angle over the wreckage. When you spot them, you can see that the entire roof beam structure shifted to the south when it fell back down.

If you shift the whole structure back to the left in picture #2 then it puts the big round hole precisely over the reactor core from picture #1.

I believe that not only did the top of the reactor blow, but possibly the entire RPV ejected and landed in a few places around the plant, but a bunch of it landed on the north end of the wreckage of reactor #3.

For any of you that have been following me elsewhere, I've got a ton of supporting evidence, but I'll leave it at that now...

See attached satellite photo.

See previous "Houdini" post:
https://www.physicsforums.com/showpost.php?p=3235897&postcount=3307

Unless the "top" came out spinning like a frisbee, at an odd angle, to the side, and squirted out before the roof girders and large overhead crane could slam back in place, then it must still under there IMO.

Further, the thermal imagery doesn't correlate with the top plug of the primary containment vessel being gone and the smoldering barrel of an RPV that has shot its wad remaining. The residual steam venting to either side of the edge of the top at the SFP and equipment pool are hard to explain if the top plug isn't still there. BTW, the top plug of the reactor isn't a single slab of concrete, but is an alternating stack of semi-circular slabs 4 layers thick. Finally, there would be some very big, very radioactive chunks of concrete, a drywell cap, and the RPV top that remain unaccounted for if what you suggest actually happened.

Edit: oops -- almost forgot -- there was the pressure data from within the RPV following the explosion of Unit 3 that still indicated an intact RPV.

I, for one, am convinced it did not. So please pardon my intransigence if I refrain from any further debate with you (or Nancy) on this point.

https://www.physicsforums.com/showpost.php?p=3235897&postcount=3307

 

[jlduh]

"TEPCO slipping behind schedule to contain accident"

http://www3.nhk.or.jp/daily/english/11_04.html

The title is almost laughable... as if there was a clear schedule to stabilize and contain this mess...

A clear strategy for containing the problem is yet to be seen 2 months after the nuclear accident occurred.

That's the very thuth!

Let's face it. We've spent here on the forum more than TWO MONTHS today discussing, analysing the infos given, trying to understand what happened and what could still happen, building theories and cutting pixels in half and more (including me!) BUT in 2 months I didn't see a credible plan from any nuclear company (including Tepco) or any nuclear agencies in the world explaining how this desaster COULD be contained. And i have more and more the impression that any schedule given will be something to create hope and give the impression that things out of any control are or "will be soon" in control. A cloud of steam to hide the core of the situation.

Maybe i missed some anticipation technical plans but really i would like to see them summarized there on this forum now after the first two months (if they ever exist). How long will we continue to lurk for tidbits of infos just being moved by day by day events? When will a global plan be discussed?

Ok Tepco has some plan to try to restore a backup closed loop cooling system reusing nitrogen pipes (any drawing of them?) on reactor N°1 which has still some containement but what else?

N°2?

N°3?

Ok I'm not in their shoes, but I'm just (like this article above) considering this simple fact: do they know what to do on a mid term/long term or NOT? My personal feeling is that they have no plan (except a draft for N°1, with lots of uncertainties) because THERE IS NO PLAN IN SUCH A SITUATION, because the nuke industry never imagined to have to handle such a situation...

So what will they do? Just keep flooding them for years (maybe 3 or 4 based on what is required for active cooling of spent fuel?)? During this time just pray for not having a new quake, a new tsunami (ohhh they are going to build a new wall in emergency, I forgot) , and not too bad typhoons. Man, let's imagine 3 seasons of typhoons washing these highly contaminated ruins and spraying radioactive materials where the winds want to bring them around... not a very sexy scenario!

And then, if we assume that after a so long time, there hasn't been any bad event like a new explosion of some kind or a fall of some fuel content of the attic SFP's, will come the time for long term containment and/or decontamination of the complete site... Where are those guys with gigantic views and nice drawings when the subject is to present the launch of some future big project for making big money? Why are they so quiet? Don't they have any credible plan? Like a nice 1 kms (or maybe even bigger) long sarcophagus, for 4 reactors and turbine buildings, that will make the Tchernobyl one a miniaturized one (the one that should be constructed to replace the old one but is still not really started, due to... lack of money and technical difficulties!)... Or whatever other plan. But i hear nothing. Just silence.

Undoubtedly, if only considering the releases in the 2 first months, and thanks to some incredible luck when you consider the details of what happened with the SFPs, this Fukushima accident could be viewed as much less severe than Tchenobyl where a bunch of radioactive material has been thrown away in the air in the first weeks. But let's now consider the time factor, and also the size factor (4 reactors plus spent fuels, so a total of 10 cores to manage!) and you will get a very different view at the "end of the story", which will be in a very long time (and this thread will die before it for sure!).

From this standpoint, no doubt that Fukushima is going to replace Tchernobyl in the minds of humanity.

 

[ernal_student]

Someone posted a link to an NHK news item from yesterday:
http://www3.nhk.or.jp/daily/english/10_30.html
The only comment I have seen is this:

That news item is absurd. Talk about comedy gold...

(I am very sorry, but I cannot quote the information properly, since almost all information is omitted when I try to use the "quote" function.)

Could someone please explain what the reply means? Perhaps I am not the only person with a native language other than English, but perhaps I am the only person who does not understand the answer. Thank you and sorry if I have wasted your time.

 

[jlduh]

Someone posted a link to an NHK news item from yesterday:
http://www3.nhk.or.jp/daily/english/10_30.html
The only comment I have seen is this:


(I am very sorry, but I cannot quote the information properly, since almost all information is omitted when I try to use the "quote" function.)

Could someone please explain what the reply means? Perhaps I am not the only person with a native language other than English, but perhaps I am the only person who does not understand the answer. Thank you and sorry if I have wasted your time.

I think that what is considered as "comedy" and stupid item is this:

The company says the radioactive substances may have become attached to debris and entered the pool together.

To achieve this level of radioactivities in the pool just with debris from the core of N°3, it would need a fair amount of debris. So either some fuel has been thrown away from the core or this is a stupid explanation from Tepco. I'm not judging, I'm trying to explain what you didn't understood in the answer.

Now if i judge, this seems odd to me also. Or they really know something that we don't know...

 

[MiceAndMen]

Someone posted a link to an NHK news item from yesterday:
http://www3.nhk.or.jp/daily/english/10_30.html
The only comment I have seen is this:(I am very sorry, but I cannot quote the information properly, since almost all information is omitted when I try to use the "quote" function.)

Could someone please explain what the reply means? Perhaps I am not the only person with a native language other than English, but perhaps I am the only person who does not understand the answer. Thank you and sorry if I have wasted your time.

That was me. The comedic aspect for me was this sentence in the article:

None of these substances were detected during an inspection on March 2nd, before the accident triggered by the March 11th disaster.

It made me laugh out loud. Of course none of those substances would have been detected before the accidents. It's an absurd statement to make in light of events that have transpired. Someone a few posts before mine had commented on something else and referred to it as "comedy gold". I view the above quote from the NHK story in the same light. "Comedy gold" is a colloquial phrase in the U.S. that means something has a high potential for humor. It's often used with a tone of sarcasm, and that's how I intended it.

 

[robinson]

Well, we only get grainy, low-res-low-bitrate videos of the plant (T-Hawk vids, fuel pool vids, etc.). I can't believe that their technical gear is so old that it can't do better than those horrible images.

It's not. They have first rate equipment and much better images than any we have seen. Evidence provided upon request.

And now we get grainy, low res .mpg vids from TEPCO... it's a shame.

While it strays into the political, I imagine if this was a US event we wouldn't have any images at all. Except from a camera 30 miles away, that sometimes went dead at certain times.

 

[Jorge Stolfi]

In the roof beams, you can see an unmistakable large round hole that has been formed in a couple of large steel beams. But the hole is in the wrong place, you say? Nope, that hole was previously excactly above the reactor core.

Not really. The reactor core is precisely centered on the building in the N-S direction, so it lies exactly under the central roof beam -- which is one of the two beams that are still intact, and in fact the only one that is still attached to a pillar on the east side.

Moreover, as others have observed, the massive overhead crane is now lying on the service floor, astride the reactor well. (Indeed it must have been the crane that protected that roof beam from the blast.) It is hard to explain how it could have ended up there after the catastrophic explosion you have imagined.

On the other hand, there may still be a slim chance that the drywell and/or its yellow cap may have ruptured and contributed to the damage, e.g. if the falling crane cracked the concrete enclosure of the drywell or pushed some debris down the reactor well. In that case the crane may have deflected the blast to the sides, again protecting the central roof beam. However, if the shield plugs were in place, that seems rather unlikely.

One thing that puzzles *me* is the demolition of the NW corner of the steam-dryer pool (SDP), whose walls seem to be a bit thicker than the walls of the building. I thought that perhaps it was a blast of steam from the ruptured drywell. But the T-Hawk photo posted by TCups shows the SDP gate is intact. Unless it blasted into the 4th storey (below the service floor) ...

Moreover, as others have noted, the drywell continued to hold substantial pressure after the explosion. On the other hand, it lost all pressure on march 21, when the Black Smoke event started. The reactor temperature went wild at the time.

Quite puzzling.

"..it goes whistling and rumbling and makes you tremble in fear;
in the end it overflows and explodes,
it propagates, it redoubles, and gives forth a huge blast, like a cannon shot;
an earthquake, a thunderstorm ..."
Rossini, The Barber of Seville, aria "La Calunnia è un Venticello"
​

 

[PietKuip]

On May 1, another 70 Bq/m2 of Cs-137 was deposited in Ibaraki.
http://www.slideshare.net/iaea/radiological-briefing-11-0505

 

[jlduh]

That was me. The comedic aspect for me was this sentence in the article:
It made me laugh out loud. Of course none of those substances would have been detected before 11 March. It's an absurd statement to make in light of events that have transpired. Someone a few posts before mine had commented on something else and referred to it as "comedy gold". I see the above quote from the NHK story in the same light.

Good you precised it because i gave a different interpretation of your "comedy"

But going back to the hypothsesis of highly radioactive debris falling in the SFP at N°3 reactor, this leads me to ask a question to try to better understand why this N03 reactor is suspected since the beginning to have released most of the highly contaminated debris around: we know that one of the explosions that occurred at N03 has destroyed the North West part of the building, which is called I think the "radwaste room". or something like that.

Do you know exactly what could be inside this part of the building: type of equipement and process, amount and type of waste, etc. This would be necessary to assess if it could explain some of the debris and high contamination rejects during N03 explosion.

 

[clancy688]

It's not. They have first rate equipment and much better images than any we have seen. Evidence provided upon request.

Um, sry... what do you mean exactly?

Version 1: There's evidence of first rate equipment used because TEPCO provides high quality images etc. to organizations such as NISA, NRC, etc?

Version 2: You have evidence and will show it if we ask for it...? ^^;

 

[sp2]

Upon further review, I guess I was wrong about the damage to the 3 and 4 superstructures in the new pix.

Looks mostly the same as it was then.

I think I got fooled by all the steam in the earlier images, and by the altered positioning of the boom over SPF 4.

Sorry to jump the gun.

 

[sp2]

Another question (again, please forgive me if I've missed some previous conclusions on this topic):

After two full months, have we gotten ANY information indicating just what it was that crashed through the roof of the Turbine Building of 3, and left that beautifully-shaped hole?

(And if not, why the hell not? Are you telling me Tepco hasn't peeked in that hole for two months now, and has no idea what it was?)

Thanks.

 

[clancy688]

(And if not, why the hell not? Are you telling me Tepco hasn't peeked in that hole for two months now, and has no idea what it was?)

Um... how do you like "Nobody asked TEPCO about the hole" as an explanation...?

 

[TCups]

Another question (again, please forgive me if I've missed some previous conclusions on this topic):

After two full months, have we gotten ANY information indicating just what it was that crashed through the roof of the Turbine Building of 3, and left that beautifully-shaped hole?

(And if not, why the hell not? Are you telling me Tepco hasn't peeked in that hole for two months now, and has no idea what it was?)

Thanks.

Ah, grasshopper! Study the photo carefully and then answer your own question.

https://www.physicsforums.com/attachment.php?attachmentid=35384&d=1305067331

 

[clancy688]

Ah, grasshopper! Study the photo carefully and then answer your own question.

https://www.physicsforums.com/attachment.php?attachmentid=35384&d=1305067331

Could I have the answer, please? There's so much in those pictures I'd like to see or I believe to see that I've come to the conclusion to only talk about what I'm _not_ seeing there... ^^Another topic:

Very interesting Fukushima presentation by Caltech: http://www.galcit.caltech.edu/~jeshep/fukushima/ShepherdFukushima30April2011.pdf

It has a big focus on hydrogen explosions and fuel failure.

 

[TCups]

Could I have the answer, please? There's so much in those pictures I'd like to see or I believe to see that I've come to the conclusion to only talk about what I'm _not_ seeing there... ^^

The panels that blew out of the east side of Unit 3's upper floor did one of two things. They either 1) cleared the rear facade of the roof of the turbine building, then skidded along the roof, smashing through the front facade of the roof of the turbine building, or, 2) they didn't quite clear the rear facade of the roof of the turbine building, whereupon, they smashed the rear facade, flipped upward, then crashed through the roof. The holes (pleural) in the roof of Turbine Bldg 3 were caused by blown out wall panels, or pieces of them, that followed the later of the two paths.

https://www.physicsforums.com/attachment.php?attachmentid=35384&d=1305067331

 

[MiceAndMen]

Do you know exactly what could be inside this part of the building: type of equipement and process, amount and type of waste, etc. This would be necessary to assess if it could explain some of the debris and high contamination rejects during N03 explosion.

I wish we knew. Unless and until TEPCO reveals that information I'm afraid we'll have to keep making educated guesses (or wait for more document leaks). I'm going to have another look at the Oyster Creek blueprints this week; it's been a while since I looked at them closely. Maybe something will stand out now that some time has passed.

Oyster Creek (BWR-2) has 2 large "emergency condensers" located one level down below the refueling floor. I'm pretty sure I read that Dai-ichi Unit 1 (BWR-3) has similar condensers, but Units 2-5 (BWR-4) do not. That's something I want to clarify.

 

[robinson]

Um, sry... what do you mean exactly?

The Manichai Daily news reports that the Japanese government has in its possession video footage of the Fukushima No. 1 Nuclear Power Plant taken by a U.S. military reconnaissance drone, but has yet to release the footage to the public, sources have revealed.

The footage taken from an RQ-4 Global Hawk drone was passed on to the Japanese government with permission for public release from the U.S. Air Force. U.S. military sources said that the decision to release the footage — or not — was up to the Japanese government.

The unmanned aerial vehicle (UAV) is equipped with a high-performance camera that, according to the U.S. Air Force, takes “footage so clear that even automobile license plates are visible.” Nearly real-time footage of the internal state of the power station is said to be captured, which is likely to assist experts in analyzing the situation.

http://www.suasnews.com/2011/03/470...se-footage-of-power-plant-taken-by-u-s-drone/

For some reason I thought the drone footage and the issue of Japan refusing to share was discussed a long time back.

There are multiple stories like the one above.

 

[SteveElbows]

Do we know whether the shield plugs (the concrete half-discs that form the lid of the refueling pool) were in place at the time of the explosion?

If I look real close at the video I posted earlier, at the very slightly visible area between the top of the dryer pool concrete gate and the bottom of the thing that has fallen, it seems possible to see a faint dark line that is slightly curved. This makes it possible to claim that we are not only able to see the concrete gate slabs, but also the very beginning of the top of one set of half-disc slabs that go over the top of the reactor, still in position where it should be. The period 3 mins 23 sec to 3 mins 29 sec offer the best glimpse of what I am speaking of.

 

[ihatelies]

See attached satellite photo.

See previous "Houdini" post:
https://www.physicsforums.com/showpost.php?p=3235897&postcount=3307

Unless the "top" came out spinning like a frisbee, at an odd angle, to the side, and squirted out before the roof girders and large overhead crane could slam back in place, then it must still under there IMO.

Further, the thermal imagery doesn't correlate with the top plug of the primary containment vessel being gone and the smoldering barrel of an RPV that has shot its wad remaining. The residual steam venting to either side of the edge of the top at the SFP and equipment pool are hard to explain if the top plug isn't still there. BTW, the top plug of the reactor isn't a single slab of concrete, but is an alternating stack of semi-circular slabs 4 layers thick. Finally, there would be some very big, very radioactive chunks of concrete, a drywell cap, and the RPV top that remain unaccounted for if what you suggest actually happened.

Edit: oops -- almost forgot -- there was the pressure data from within the RPV following the explosion of Unit 3 that still indicated an intact RPV.

I, for one, am convinced it did not. So please pardon my intransigence if I refrain from any further debate with you (or Nancy) on this point.

https://www.physicsforums.com/showpost.php?p=3235897&postcount=3307

Did you read the second part of my post? The second picture I posted proves it didn't have to come off "spinning like a frisbee". The entire roof structure is moved exactly one section to the south. Which puts that hole directly over the reactor core.

And I don't necessarily believe the thermal imagery, since it showed the whole shebang as at very low temps.

So first off, do you believe something went vertical through that hole?

 

[robinson]

Related question. Isn't one continuous steam cloud coming from reactor 3? And the other one from the fuel pond?