Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[SpunkyMonkey]

The video, I've found, makes more easily sense if it is rotated something like 180-270 degrees.

It's difficult to know up and down in the footage. There appear to be some streaking stains in the hotspot that may suggest gravity-directed flow and if so, either the given footage at that time is up-down oriented or a 180˚ rotation of it is. Ah! The tiny objects I posted above should be resting on the ground, so at least we can assume that surface they're on would be down/bottom/floor.

I wonder if the camera went through a crack at the seam of the hatch and the hotspot is actually in the PCV.

I think there may have been a rapid movement of the camera a this striking change of scene and pick-up of radiation, or perhaps the video could at this point have been redacted, (while it otherwise does give the impression of being a continuous recording.)

It seems that it may be continuous footage, but it's hard to be sure. Consistent with the hatch area, I think we're seeing metal surfaces at and near the 'hotspot', hence rusty-colored stains.

 

[MadderDoc]

<..> Ah! The tiny objects I posted above should be resting on the ground, so at least we can assume that surface they're on would be down/bottom/floor.

Right, that's why my brain would prefer the image to be rotated 180 degrees, such that it mimics what my eyes would see if I were standing there facing the wall looking down towards the floor.

I wonder if the camera went through a crack at the seam of the hatch and the hotspot is actually in the PCV.

Since that scene is followed shortly by scenes showing the final extraction of the scope from the cavity, I'd tend to think it is nowhere near the PCV hatch. The sudden increase of radiation, giving the impression of hitting a hotspot, might be just caused by the sensor suddenly coming close to the contaminated floor.

It seems that it may be continuous footage, but it's hard to be sure. Consistent with the hatch area, I think we're seeing metal surfaces at and near the 'hotspot', hence rusty-colored stains.

I've been looking too at the different textures of the surfaces shown in the video in search of a possible metal surface that could be the actual concave surface of the hatch door in the far end of the cavity that was scoped.
My best candidate, considering it would have to be somewhere halfways into the mission would be the surface that is most clearly shown around frame 3045 (at 1:41.50) (frame attached) . However following on the travel of the camera, this comparatively neat surface appears to me to transform gradually and seamlessly into something more disorderly, ultimately to become that yucky rusty oozing and irregular surface which Tepco has told us is the water they found on the floor, as result of the mission. So, putting on my coolest head, I'd have to say this mission may well not have included an inspection of the area close to the hatch at all.

 

[SpunkyMonkey]

Since that scene is followed shortly by scenes showing the final extraction of the scope from the cavity, I'd tend to think it is nowhere near the PCV hatch.

Maybe. If the apparent falling chips "www.youtube.com/watch?v=zndssc4qe7g#t=2m9s" are falling down, then isn't the rusty-colored 'slime trail' running down the wall? The streaks of the chips are primarily parallel to the slime trail. So if the trail isn't running down the wall, the chips are flying above and across the floor, which seems very unlikely.

Update: pretty sure I've oriented myself within the U3 hatch video. The slime trial runs down the wall at the interface of the metal hatch insertion into the concrete containment, just a few feet from the hatch door. Appropriately, this is within Tepco's encircled area "Place of photo taken in this inspection." The paint chips flake off the metal hatch-insertion wall (not the hatch door itself) to the right of the slime trail, and to the left of the slime trail the wall is concrete.

"www.youtube.com/watch?v=zndssc4qe7g#t=2m5s" takes you to the video when the camera is hugging along the metal paint-chip-flaking wall of the hatch insertion, then the camera moves to the slime trail then over the concrete wall left of the slime trail. Notice the distinct difference of the wall to the right and left of the slime trail, and the concrete wall isn't painted there. This difference of painted and not-painted walls on either slide of the slime trail is key to this orienting.

 

[MadderDoc]

Maybe. If the apparent falling chips "www.youtube.com/watch?v=zndssc4qe7g#t=2m9s" are falling down, then isn't the rusty-colored 'slime trail' running down the wall? The streaks of the chips are primarily parallel to the slime trail. So if the trail isn't running down the wall, the chips are flying above and across the floor, which seems very unlikely.

I think it is safe to say that the camera is most of the time if not consequently pointed downwards towards the floor. However, not perpendicularly, otherwise there would be no component of up and down in the images. Streaking chips might be able to indicate up and down, assuming their motion is guided by only gravity, on the condition that we can see the same chips in two successive frames, and thereby judge the direction they are apparently moving.

I have attached two such successive frames from the sequence of the youtube video you reference, and clearly we there see the chips moving upwards in the images. That's one reason I think the video is better viewed rotated by about 180 degrees.

(The attached frames are frames no 3928 and 3929 of the youtube video, corrresponding to frames no 3894 and 3895 in the original video released by Tepco. Youtube is a great convenience indeed, but the material there has been re-compressed from the original and has lost quite some detail in the process)

 

[MadderDoc]

<..>
Update: pretty sure I've oriented myself within the U3 hatch video. The slime trial runs down the wall at the interface of the metal hatch insertion into the concrete containment, just a few feet from the hatch door. Appropriately, this is within Tepco's encircled area "Place of photo taken in this inspection." The paint chips flake off the metal hatch-insertion wall (not the hatch door itself) to the right of the slime trail, and to the left of the slime trail the wall is concrete.

Well, I am not ready to accept that interpretation. It would put the slime trail which Tepco says is on the floor, on the wall. It is not that I assume Tepco is immune to making an error, but I will have to assume they do know the place a lot better than I do.

 

[SpunkyMonkey]

Well, I am not ready to accept that interpretation. It would put the slime trail which Tepco says is on the floor, on the wall. It is not that I assume Tepco is immune to making an error, but I will have to assume they do know the place a lot better than I do.

If it's not the wall, the paint chips mostly fly horizontally over the floor. That's my only reason for suggesting the slime trail is along the wall. The "www.youtube.com/watch?v=zndssc4qe7g#t=1m50s" starts on the frames Tepco attributes to the floor, eventually pulls out and the chips fall mostly parallel to the trail.

Re your point on youtube videos, unfortunately I can't work with Tepco's wmv files. I'm on a Mac and my video program is Premiere Pro, to which wmv files are inaccessible. Go figure! So I have to rely on second-generation reposts to youtube. :(

Btw, your 180˚ rotation idea makes the content appear to fit with the handout-stipulated location better. It also causes the exit path to match the Access route stipulated in the hand out.

 

[MadderDoc]

<..>
Regarding any buildup of water between the concrete shell and the PCV (post explosion) - Apart from this shield plug area where else might it flow to at a reasonable rate? <..><..>

A banality, but it would flow wherever gravity could take it. Once the cat is out the bag there's no telling by which route it will eventually escape the garden. I would assume though, that there is free passage ways from the outside surface of the drywell to the torus room, so that could be one waystation.

There's one thing I find weird about the plan of gradually filling the reactor to the very top, while finding and repairing the leaks that turn up, as you go, while the water is rising. How will it even be possible to locate the leaks? Certainly they cannot be seen from outside of the PCV, due to that pesky layer of concrete surrounding it and the fine cavity between the PCV and the concrete, which so easily will transport water elsewhere, far from the leak. How can one find the location of a leak in the PCV, from observing that it oozes somewhere downstream through cracks in the concrete shield? Do you fill the vesssel until it oozes too much then back down, lower the waterlevel find the leak repair it, then try and fill, and try and try again?

The prospects of the water filling plan, it would seem to me, will be an almost endless battle against leaks. (And no, I do not come with a better plan.)

 

[MadderDoc]

If it's not the wall, the paint chips mostly fly horizontally over the floor. <..>

But you can't actually see that they fly horizontally, only interpret it that way. If you look down against a floor in an angle, and an object drops from above through your FOV, it will seem geometrically against the background, exactly as if it is racing against you along the floor. In real world your depth vision and knowledge of relative sizes and distance will inform you that it is actually not, but that does not work well with a 2D video from a strange and foreign land.

 

[westfield]

For reference - An earlier image of U3 Equipment hatch shield plug - both "cabinet" doors are open in this shot - from this handout dated May 12th 2011

 

[biggerten]

A banality, but it would flow wherever gravity could take it. Once the cat is out the bag there's no telling by which route it will eventually escape the garden. I would assume though, that there is free passage ways from the outside surface of the drywell to the torus room, so that could be one waystation.

There's one thing I find weird about the plan of gradually filling the reactor to the very top, while finding and repairing the leaks that turn up, as you go, while the water is rising. How will it even be possible to locate the leaks? Certainly they cannot be seen from outside of the PCV, due to that pesky layer of concrete surrounding it and the fine cavity between the PCV and the concrete, which so easily will transport water elsewhere, far from the leak. How can one find the location of a leak in the PCV, from observing that it oozes somewhere downstream through cracks in the concrete shield? Do you fill the vesssel until it oozes too much then back down, lower the waterlevel find the leak repair it, then try and fill, and try and try again?

The prospects of the water filling plan, it would seem to me, will be an almost endless battle against leaks. (And no, I do not come with a better plan.)

You make a valid point. But how do you eat an elephant? One bite at a time.

 

[SpunkyMonkey]

I rotated the hatch-inspection video 270˚ and that makes its orientation correct, at least at the beginning as the cameraman walks up to the cervice. Notice that the cabinet westfield points to above appears properly oriented with its top on top in the rotated version:

Hatch-Inspection Video Rotated 270˚ & Original, 3X Fast​

However, as the video proceeds from shield-plug-cervice entry, the camera appears to be able to rotate itself, so there's still some uncertainty as to which way's up once its probing around the hatch passageway. But I'm confident that the 'slime trail' is at the interface, or flange, of the metal hatch insertion into the thick concrete containment wall, which jibes with Tepco's description of this inspection.

 

[jim hardy]

I think it is safe to say that the camera is most of the time if not consequently pointed downwards towards the floor. However, not perpendicularly, otherwise there would be no component of up and down in the images. Streaking chips might be able to indicate up and down, assuming their motion is guided by only gravity, on the condition that we can see the same chips in two successive frames, and thereby judge the direction they are apparently moving.

I have attached two such successive frames from the sequence of the youtube video you reference, and clearly we there see the chips moving upwards in the images. That's one reason I think the video is better viewed rotated by about 180 degrees.

(The attached frames are frames no 3928 and 3929 of the youtube video, corrresponding to frames no 3894 and 3895 in the original video released by Tepco. Youtube is a great convenience indeed, but the material there has been re-compressed from the original and has lost quite some detail in the process)

You fellow's expertise with video is awesome.

Dummie question here:

those (whatever they are) are so brief and fast moving - do they not cross the whole field of vision in one frame? They resemble the sparks one sees from a surface grinder... seem to have distinct direction and come in short bursts.

If i accept the bright flashes as probably gammas affecting the camera
Might those (chips, rays, whatever) be bursts of different radiation? Could alphas or betas make it through the camera enclosure and leave wider tracks in the camera's retina(for want of proper term)? Gamma is to Alpha as Gnat is to Cannonball .
One of them appears to reverse course in upper left of your attached single-frame.

Just one of the dumb things a troubleshooter has to rule out. One needn't even admit he considered it after he understands why it isn't plausible. I'm not quite there yet.

old jim

 

[westfield]

Well, I am not ready to accept that interpretation. It would put the slime trail which Tepco says is on the floor, on the wall. It is not that I assume Tepco is immune to making an error, but I will have to assume they do know the place a lot better than I do.

Spunky & Madder I may be wrong but I'm fairly sure that once you get past roughly halfway into the plug penetration it transitions from square opening to round - so there are likely no corners \ floor \ walls once you are in there at the PCV hatch.

The transition is here - @ around 1:08 in the clip

I may be wrong again but these do look quite like a PCV hatch and flange.
Looking Straight at hatch, along "wall" at hatch. across hatch to wall ---

So I can tell it's a bit damp and rusty in there.
I hope the excerise was more useful to Tepco.

Edit to add this Equipment Hatch image from Onegawa NPP Unit (Toshiba BWR variant). Rectangular plug shape seems more representative of the Fukuichi hatches than the USA hatch images.

 

[MadderDoc]

If I understand the lingo of the trade, it has been practised to distinguish between the possibility of in-vessel steam explosions, and ex-vessel steam explosions, respectively, in nuclear reactors. 'Vessel' in this context would mean the reacture pressure vessel, the RPV. The likelihood of a steam explosion inside the RPV (an 'in-vessel' explosion) during accident condition has been ranked low, since due to the high temperature and pressure already existing in the vessel -- which is designed for high pressure -- an extraordinary large amount of energy would seem to be needed for a high pressure surge of sufficient magnitude to break it.

The possibility of steam explosion in the primary containment ('ex-vessel') otoh, has been considered, in the embodiment of an assumed sudden drop of a hot corium mass from the RPV bottom into water during an accident. In this embodiment, heat from the corium mass is rapidly being transferred into the cold water of a depressurised primary containment, yielding an explosive evolution of water vapor and a high pressure surge in the primary containment of sufficient magnitude to break it.

I have not seen other embodiments of possible ex-vessel steam explosions described in literature or official documents relating to the accident. And specifically not any which would seem relevant to the explosion of unit 3, in which, at the time of the vent, the primary containment vessel was already at a dangerously high pressure and temperature. It would seem to me, that it might take a relatively low pressure surge to break an already overloaded vessel, and with potentially more explosive consequences.

Yet, in na'r an official document can you find reference to the explosion in unit 3, without being told implicitly that nothing but the possibility of a hydrogen explosion --an 'ex-ex-vessel' hydrogen explosion so to speak -- in the upper floors of the building has been found worth considering, but really hasn't, while it is all just 'believed to be' or 'assumed to be' what happened, nothing more, nothing less, and nothing is learned.

In the good old days of the boiler explosions that stance would have seemed strangely un-curious, they even explored the possibility that boiler explosions could be caused by high heat splitting of water molecules into hydrogen and oxygen -- although that theory would eventually be dismissed, it was at least considered. Many theories were flouted as to why boilers exploded, and the result of all that work led to a better understanding of the mechanisms of boiler explosions so we could from then on better avoid their occurrence.

 

[SpunkyMonkey]

Well, I am not ready to accept that interpretation. It would put the slime trail which Tepco says is on the floor, on the wall. It is not that I assume Tepco is immune to making an error, but I will have to assume they do know the place a lot better than I do.

I believe this shows that when the camera encounters the 'slime trail' (leakage at hatch flange) the camera had been 'crawling' along the same wall that it entered along at a height of about 3 feet:

"www.youtube.com/watch?v=-bV48eXSHXY&hd=1"​

When the camera hits spots that are so reflective the screen whites out (as is the case at the last corner before the slime trail) in the original, I reduced the brightness and contrast at those points so as to recover washed-out visual detail. I believe the results show that the camera keeps looking at the same wall from moment of entry to slime-trail encounter, hence the trail is on the wall.

Now, the camera does rotate as it approaches the slime trail and this gradually orients the slime trail to horizontal (on screen), giving the impression that it's on the floor (perhaps the cause of an error in the handout if it is an error). However, that the camera rotates is made clear by the fact that the trail's horizontal-vertical orientation changes across a wide range of angular orientations.

Also, these two frames appear to capture the same paint chip as it falls parallel to the slime trail seen behind it (orientation is to the original video):

I can't see any better interpretation than that that chip is falling down (and its streak matches the vast majority of other chips) and since it falls parallel to the trail seen behind it, the trail runs down the wall. The implication of my interpretation is that the floor may never be viewed beyond the initial entry threshold and it might have pooled water on it if the slime trail has fresh water running down it, which does seem glossy as if wet. Floor pooling assumes its level in that area is below the dry floor at the entry, which is possible.

 

[jim hardy]

Yet, in na'r an official document can you find reference to the explosion in unit 3, without being told implicitly that nothing but the possibility of a hydrogen explosion --an 'ex-ex-vessel' hydrogen explosion so to speak -- in the upper floors of the building has been found worth considering, but really hasn't, while it is all just 'believed to be' or 'assumed to be' what happened, nothing more, nothing less, and nothing is learned.

Are you hinting that what has not been said might speak volumes?

When the cameras get to the area of PCV flange then on to RPV upper and lower heads it'll end a lot of speculation.

 

[SpunkyMonkey]

Spunky & Madder I may be wrong but I'm fairly sure that once you get past roughly halfway into the plug penetration it transitions from square opening to round - so there are likely no corners \ floor \ walls once you are in there at the PCV hatch.

Notice at the last corner before the slime trail, the wall looks pretty flat. But maybe you're right and it goes to a circular passage there, I'm not 100% sure either way.

Update: consistent with your theory, I think the slime trail may be seen to curve upward in the first frames where we get a quick look down its length. Or that might be camera 'fish-bowl' distortion.

I may be wrong again but these do look quite like a PCV hatch and flange.
Looking Straight at hatch, along "wall" at hatch. across hatch to wall ---

I'm tempted to agree, and as such in viewing the 'hotspot' we're not really looking at a new place. I'm thinking maybe the burst of ccd snow is caused by the camera being closer to an unvisualized floor were highly contaminated water has pooled. That burst of snow has to mean something unique me thinks.

 

[MadderDoc]

Gentlemen, it is such a pleasure working with you. On reviewing the video using autogain, as inspired by Spunky's wonderfully improved video, and using westfield's directives along the route, I get the timeline below of the camera position relative to landmarks of the cavity wall.

Position A is at the outside wall of the concrete shield, B is at the first notch on the wall, C is a small notch in the wall which I would think is close to as far as the plug goes, when it is fully inserted. Behind C and deeper into the void, we are inside the room that was behind the plug in its normal position. At D not far from C, the room seems to narrow in considerably, which might mean we are now inside the cylindrical part of the hatch construction, and we could potentially now be seeing the lid of the hatch at some time during the approximately 2 minute sequence which follows, until the camera finally exits.

Entry times:
A: 0:54.4
B: 0:58.4
C: 1.07.8
D: 1.09.0

Exit times
D: 3:05.3
C: 3:08.0
B: 3:19.0
A: 3:31.2

To westfield: I suggest there might be a bottom insert in the metal portion of the hatch, such as to produce a horizontal floor inside it. I imagine that could be practical for equipment loading and unloading through the hatch, and the previously posted photo from that METI/industry document of an open hatch seen from inside of the PCV appears to have such an insert.

To Spunky: looking at these streaking particles, there are times I get this weird impression that they move as being taken by a wind, is it only my brain doing this, is it some kind of illusion, or is there a draught at the floor in that room?

To both of you: Could that yucky rusty patch be on such presumed horizontal floor inside the metal portion of the hatch?. I can't get away from Tepco's statement that the water is seen on a floor.

 

[MadderDoc]

Are you hinting that what has not been said might speak volumes?

In a way, maybe, similar to the curious incident of the dog (it didn't bark), in the short story Silver Blaze.

("Is there any point to which you would wish to draw my attention?" "To the curious incident of the dog in the night-time." "The dog did nothing in the night-time." "That was the curious incident," remarked Sherlock Holmes.)

When the cameras get to the area of PCV flange then on to RPV upper and lower heads it'll end a lot of speculation.

Well there's some way to go to get there yet, but they do seem to be building a platform, which could be suitable for such attempts.

(photo cropped from: http://www.sdnyw.cn/news/edit/UploadFile1/201231292418951.jpg)

The photo above, btw, establishes certainty about what is the dark shape we have seen in poorer photos, at the east side of the equipment pool, at the close end to the reactor area. It is not anything but a big hole in the fifth floor, apparently blown upwards from below. Previous photos from above would then suggest that the damage below goes as far as to the 3rd floor. The hole in the floor would seem to be a likely candidate for the apparent source of the black smoke event on March 21st, one week after the explosion. No close up photos have been published of the possibly related http://192.168.168.11/tepcowebcam/20110323180100.jpg

 

[MadderDoc]

<..>Could that yucky rusty patch be on such presumed horizontal floor inside the metal portion of the hatch?. I can't get away from Tepco's statement that the water is seen on a floor.

I've thought about, looked a bit more on this video, and perhaps the indications of Tepco matters less as regards which surface this water is seen, than as regards which type of damage is indicated. I may have just got a false impression of what Tepco intended to convey. Although I am still not quite sure what I see in the video, it seems a far cry from just a puddle in some rails, or a leaking gasket. I do understand the video might have given some pause for thought.

 

[MadderDoc]

You make a valid point. But how do you eat an elephant? One bite at a time.

Yeah, always. But how do you roach it... :-)

OK, water-filling to the fifth floor of these tormented structures. Plan B?

 

[SteveElbows]

For now I'm keeping an open mind on the reactor 3 equipment hatch video, since issues of scale as well as orientation play tricks on me.

Meanwhile there are a couple of good images of people visiting the upper floor of reactor 4 here, including the covered fuel pool and a view of the top of the reactor well.

http://photo.tepco.co.jp/library/120423_01/120423_03.jpg

http://photo.tepco.co.jp/library/120423_01/120423_04.jpg

 

[SteveElbows]

The photo above, btw, establishes certainty about what is the dark shape we have seen in poorer photos, at the east side of the equipment pool, at the close end to the reactor area. It is not anything but a big hole in the fifth floor, apparently blown upwards from below. Previous photos from above would then suggest that the damage below goes as far as to the 3rd floor.

The thing that was described a long time ago as 'snaggle tooth' and that I spent a while on debunking the idea that it was the top of containment?

From that photo I am not sure as it is a hole, it could be, but it could also be something that has melted/burnt. I believe there is a little bit of melted black substance hanging off the roof beams that are above this area, not sure if its related.

As for whether it has anything to do with the black smoke event, it might, but there isn't much that let's us take this idea much further.

edited to add picture where black stuff on roof beam can be made out.

 

[Rive]

... a big hole in the fifth floor, apparently blown upwards from below. Previous photos from above would then suggest that the damage below goes as far as to the 3rd floor.

We have some floorplans from U2 survey maps, so maybe we can find out something about the affected areas.

 

[westfield]

<snip>To westfield: I suggest there might be a bottom insert in the metal portion of the hatch, such as to produce a horizontal floor inside it. I imagine that could be practical for equipment loading and unloading through the hatch, and the previously posted photo from that METI/industry document of an open hatch seen from inside of the PCV appears to have such an insert.

<snip>

To both of you: Could that yucky rusty patch be on such presumed horizontal floor inside the metal portion of the hatch?. I can't get away from Tepco's statement that the water is seen on a floor.

When any of these PCV hatches are open I would be very surprised if there was not always some sort of cover to protect at least the seal seat on the flange if not the whole flange from damage and as you say, to make the hatch trafficable. We see such "bridges" in the Browns Ferry & the Onagawa equipment hatch images and in those it's clear the "bridges" would be removed when the PCV hatch is closed out.

Additionally, I don't think anything loose at all would be left in the shield plug void and I don't think there would be anything permanent that might tie or create possible interference with the concrete \ steel interface at operational temperatures.

So I'm only guessing but personally I wouldn't think there would be any sort of "step" mounted in the equipment hatch flange itself or near it. I've been reading about Onagawa NPP damage due to earthquake only. Quite eye opening.
Amongst that there is this ( taken from this report )

Onagawa PCV equipment hatch shield plug

How much it broke it's lock and moved

Shield plug movement mystery solved?

 

[HowlerMonkey]

Lots of combustible materials outside containment but within the buildings.

 

[jim hardy]

the dark shape we have seen in poorer photos,

great images guys, guess i haven't been keeping up."Snaggletooth" was a shadowy apparition in several early photos. I've seen no further hints of him since March last year.

old jim

 

[westfield]

The thing that was described a long time ago as 'snaggle tooth' and that I spent a while on debunking the idea that it was the top of containment?

From that photo I am not sure as it is a hole, it could be, but it could also be something that has melted/burnt. I believe there is a little bit of melted black substance hanging off the roof beams that are above this area, not sure if its related.

As for whether it has anything to do with the black smoke event, it might, but there isn't much that let's us take this idea much further.

edited to add picture where black stuff on roof beam can be made out.

<snip>Well there's some way to go to get there yet, but they do seem to be building a platform, which could be suitable for such attempts.

<snip>The photo above, btw, establishes certainty about what is the dark shape we have seen in poorer photos, at the east side of the equipment pool, at the close end to the reactor area. It is not anything but a big hole in the fifth floor, apparently blown upwards from below. Previous photos from above would then suggest that the damage below goes as far as to the 3rd floor. <snip>

Is that one of the platforms for the demolition work in your previous post?

You mean this hole in the floor adjacent to the DS pit was uncertain? ;) (March 30 2012 image)

Steve what was the date for the "black smoke" event? As you also noticed on aerial shots sometime between the March 20th and the 24th the roof truss directly over that hole seems to have taken on a sooty appearance. Edit : I'm not referring to the black sheet of roofing membrane or whatever it is.

Around March 20th 2011, Around Mar 23 and then Mar 30.

Re damage in U3 - if you watch the recent PCV equipment hatch clip there are several glimpses of more significant disarray on FL 1 than we have seen before. It's not so tidy down there. The reason I mention that in relation to the hole in FL5 floor is I was reading an interesting report last night that included some modeling of the U3 hydrogen dispersion and subsequent deflagration. That particular modeling placed the ignition source on 1FL of U3. I will try to find the link. I didn't bother at the time because I thought it would have been posted here already. It seemed quite authoritive. It was a reprt from Nisa or METI or someone like that.Is that modelling and the first floor ignition point something new?

 

[MadderDoc]

The thing that was described a long time ago as 'snaggle tooth' and that I spent a while on debunking the idea that it was the top of containment?

From that photo I am not sure as it is a hole, it could be, but it could also be something that has melted/burnt.

Yes, that was a fair alternative explanation. What finally clinches it for me as a hole is that in the new photo I can now clearly see the bent up rebar at the far side. But already the previous best photo of the location I felt strongly suggested a hole:

(crop, color-releveled & de-distorted, from http://photo.tepco.co.jp/library/111008_1/111008_05.jpg )

I believe there is a little bit of melted black substance hanging off the roof beams that are above this area, not sure if its related.

As for whether it has anything to do with the black smoke event, it might, but there isn't much that let's us take this idea much further.<..>

Oh Steve! We can do better, we can put to rest that idea once and for all :-)
The black substance was there on those roof beams with a quite similar attire in photos from the day before the first black smoke event, so it had nothing to do with any of those.

It appears to be some flexible material, and has always had a weird 'green-metallic' look. I have no idea how it got there, but would assume it came there as a result of the explosion. It can be fairly hypothesised, seeing the way it has been apparently closely draped around the beams that it may have been shaped by heat influence, either from landing there while the beams were still hot after the explosion, or from the heat influence of the massive amounts of steam that came out of the primary containment vessel during the first couple of days after the explosion.

 

[MadderDoc]

<..>Is that modelling and the first floor ignition point something new?

It is to me, at least (drool).

 

[westfield]

It is to me, at least (drool).

ok I will trawl through my browser history and try to find the link.
Don't ruin your shirt though, it was only a one or two page summary of the modelling in amongst a lot of other summaries.

Edit : While I look for that- I don't know if this report has been posted.
I had always wondered what happened to the roller door of the Unit 3 TB.

This emergency response report has lots of interesting details of the immediate on site actions that I'd never read in other reports, such as why they drove a truck through the Turbine Building roller door.

Edit Edit : Holy C*** - what are the odds two people would post a link to the same report at virtually the same time!

 

[MadderDoc]

Perhaps relevant to some of the current topics of discussion:
(from http://icanps.go.jp/eng/120224Honbun04Eng.pdf )

"At around 14:31 that day [March 13th 2011], a high radiation level of more than 300 mSv/h was detected north of the double-entry door of the Unit 3 R/B, white haze was observed inside the double-entry door and a level of 100 mSv/h was detected south of the double-entry door."

" Since white haze filled the first floor of the Unit 3
R/B and their APDs showed high readings at that time, they evacuated from the building."

 

[MadderDoc]

ok I will trawl through my browser history and try to find the link.
Don't ruin your shirt though, it was only a one or two page summary of the modelling in amongst a lot of other summaries.

Well, I'll be happy to read it if you can find it without too much trouble. Whereas there are signs of damage just about anywhere of unit 3, this damage seems to me to be centered about the 3rd,4th and 5th floor, and the primary containment. Hum. Perhaps centered is not the right word for such widespread destruction. Anyhow, not particularly centered about the 1st floor.

 

[westfield]

Well, I'll be happy to read it if you can find it without too much trouble. Whereas there are signs of damage just about anywhere of unit 3, this damage seems to me to be centered about the 3rd,4th and 5th floor, and the primary containment. Hum. Perhaps centered is not the right word for such widespread destruction. Anyhow, not particularly centered about the 1st floor.

This is the summary report - the summary about the U3 explosion modelling is around page 69. Quite a few other things in there as well. It says the full report will be posted here at METI soon

Edit : also a few pages before that , I hadn't seen that exact radiation map of U3 of around the equipment hatch before.
Am I mistaken or was that particular reading at the U3 equipment hatch shield plug left out of the previous map?

To be honest there are so many duplicate, updated and derivative reports around I often find it difficult to keep track.
I don't know how Tsutsuji san and other dedicated posters manage to keep tabs on it.
Kudos to them.

 

[SteveElbows]

That report is rather interesting. On page 56 it says that they have a new possible explanation for slower PCV pressure rises at reactor 2 than the model predicts - that seawater getting into the S/C room contributed to the slower rise of pressure!