Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[clancy688]

Different Topic:

Unit 1 IC mystery - why did they shut down the IC on March 11th after 6 pm when they activated it barely a couple of minutes ago?

So I had this idea...

Here's a 1991 GE patent for an Isolation Condenser:

http://www.patentgenius.com/patent/5158742.html

It's noted that:

In order for the isolation condenser to be effective for maximizing heat transfer from the reactor steam to the pool water, the tubes must be relatively thin and single walled, but, they must be also strong enough to contain the relatively highpressure of the reactor steam being channeled therethrough. Since the reactor steam is channeled through the containment building and through the condenser tubes disposed outside thereof, the tubes themselves provide only a single barrier againstrelease of the reactor steam, which is radioactive. If one or more of the condenser tubes fails during operation, the reactor steam will leak into the isolation pool and be released through a conventional vent to the atmosphere, which therefore wouldrelease radiation to the atmosphere outside the containment building.

In order to reduce the risk of radioactive steam release from the condenser in the event of a failure thereof, conventional isolation valves are provided both in the conduits leading from the pressure vessel or containment building to theisolation condenser and in the conduits returning the condensed steam back to the pressure vessel. The isolation valves are normally closed valves which must be energized to open during operation so that, upon any failure of the isolation condenserwhich might release steam therefrom, the fail-safe condition will allow the valves to close upon interruption of power thereto which will stop the flow of reactor steam to the isolation condenser and, therefore, prevent any further release of radiationto the atmosphere.

Perhaps they feared that high reactor pressure would burst the IC-tubes? And that's why they shut it down...

 

[MadderDoc]

The orientation marked "4" on that diagram is misleading.

I see what you mean, it also thought it could be more instructive. But the intent of the arrow to mislead is plausibly deniable. The arrow points as best it can to an object that is not visible in the drawing.

Here is a quick diagram I made that didn't turn out that clear and features some terrible abuses of perspective & photoshop :)

Neat. See that is more instructive! Attached is a suggestion for modification of the markup of unit 3 added x-beams, as I think they are at that end of the bridge.(Lest it might mislead into thinking you've seen more of the length of the bridge in that video, than you actually have.)

 

[MadderDoc]

<..>
Perhaps they feared that high reactor pressure would burst the IC-tubes? And that's why they shut it down...

Yes, maybe. According to the most recent narrative of events, the IC was switched on, while it was observed whether steam would be emitted from the IC exhausts. (Immediate powerful steam emission from the exhaust on operation of the IC was apparently thought of as indicating correct operation) As little or no steam was observed it was thought the system was not operating properly due to low water level in the condenser, and the system was shut down out of fear that "uncooled steam may cause IC pipes to break and result in releasing contaminated radioactive steam into the atmosphere."

 

[zapperzero]

housekeeping

PS - if this sort of post is getting just too off track then someone please say so - it is a bit of a messy thread at times and perhaps another thread for this sort of PCV hatch \ FHM \ Holes in floor type of discussion would be useful and make this sort of thing less disruptive to this thread? Perhaps rename & recycle the Unit 2 thread which is very quiet.

I'd rather not, given the #3 explosion thread debacle. Perhaps we all could start using post titles properly instead?

 

[tsutsuji]

http://www.meti.go.jp/earthquake/nuclear/pdf/120423/120423_02n.pdf Plan to reduce volumes of groundwater seeping into units 1~4 buildings by groundwater bypass

Page 2/12
Outline
Measures dealing with liquid waste

Concerning liquid waste, in the future we shall perform the necessary studies mentioned below, and by performing the related countermeasures, it is intended not to simply release contaminated water into the sea.

①Radical measures against groundwater seeping into reactor buildings, etc., which is responsible for water increase.
②Measures for securing the upgrading of the decontamination capacity of the water decontamination facilities and for securing the stable running of those facilities including backup equipments to be used during breakdowns.
③Further installation of onshore equipments for contaminated water management
It must be noted that without the approval of concerned ministries, releases into the sea will not be performed.
↓
It will continue in the future
↓
As a radical measure against groundwater seeping into buildings, we are currently working for the recovery of the subdrains, but especially around the reactor buildings, the radiation dose being high, the degree of difficulty is high.
↓
As an auxiliary measure in support of the subdrain, the following items are proposed:
↓
■ The groundwater that flows down from the mountain side is to be pumped from a point upstream from the buildings (O.P. + 35 m level), and the watercourse is changed (groundwater bypass).
■ As a consequence of the groundwater bypass, the underground water level in the surroundings of the buildings (especially on the mountain side) is lowered, and the seeping volume into building basements is regulated.
■ The pumped water is bypassed to the sea using a special channel. Also, monitoring of the water quality is performed.

Page 3/12
Concept

Present status
■Water mainly flows through the permeable layer from mountain side to seaside.
■Part of the groundwater seeps into the buildings during its way to the sea → increase of accumulated water inside buildings
■In order to regulate the volume of groundwater seeping into the buildings, the subdrain system is under restoration

↓
Proposal
■ The groundwater that flows down from the mountain side is pumped from a point upstream from the buildings, and the underground water's watercourse is changed (groundwater bypass).
■ As a consequence of the groundwater bypass, the underground water level in the surroundings of the buildings (especially on the mountain side) is lowered, and the seeping volume into building basements is regulated.
■As before, the subdrain system restoration work continues

Page 4/12
Feasibility status

Page 5/12
Estimated effects
Assumption used to calculate effects : groundwater flows through building side walls as a consequence of the difference between the groundwater level and the inside building water level.

 

[tsutsuji]

page 6/12
Implementation steps
【Step 1】 check of water quality using the existing 3 boreholes
【Step 2】 check of water quality in pumping wells (sequentially implemented)

【Step 3】 Lowering of groundwater level due to groundwater bypass (gradually implemented)

* As a result of operating gradually and of monitoring, implementation is done while checking water quality and groundwater level decline status etc.
* In accordance with the groundwater level decline, the lowering of the buildings' accumulated water levels is performed.
* As the lowering (recovery) of the water level surrounding buildings takes several months, water level management is carefully performed so that the buildings' accumulated water does not leak outside.

page 7/12
Abridged schedule

While checking water quality and groundwater level decline status, etc. , implementation is done gradually and carefully.

 

[tsutsuji]

page 8/12
Attachment 1: Present status of groundwater water quality

*Cs-134 and Cs-137 are, as shown below, below 1 Bq/l when added together.
*In the future, continuous monitoring is planned

Analysed nuclides : all gamma nuclides, all alpha, all beta nuclides, tritium
Analysis results : all gamma nuclides, all alpha, all beta nuclides were below detection threshold

※ detection threshold : all alpha = 3.0 Bq/l, all beta=6.7 Bq/l, Cs-134, 137: see table below

※ radiation monitoring performed by ministry of environment for groundwater and public bodies of water

Tritium detection

* At A and C it is not detected. At B a low concentration (one thousandth of the notification standard) was detected.
* It is presumed that as a consequence of the nuclear plant accident, tritium was released as steam, and fell on the ground, and was absorbed.
* The beta rays generated by tritium have a low energy and the effect of exposure is small.

measuring time= 15,000 seconds, notification threshold= 60,000 [I guess it is Bq/l]

 

[tsutsuji]

page 9/12
Attachment 2: Check of feasability (seapage flow analysis) (1)
Groundwater level status (subdrain shutdown)

page 10/12
Attachment 3: Check of feasability (seapage flow analysis) (2)
Groundwater level and flow speed vector (subdrain shutdown, groundwater bypass in operation)

page 11/12
Attachment 4: Check of feasability (seapage flow analysis) (3)
Groundwater level decline

 

[tsutsuji]

page 12/12
Attachment 5: Check of feasability (seapage flow analysis) (4)
Check of lines of flow
(Check of the flowing direction of groundwater due to the operation of the groundwater bypass, in the vicinity of the buildings)
Particles (yellow dots) are set in the buildings' side walls (all corners and 50 m pitch) and their lines of flow are analysed

 

[SpunkyMonkey]

However note that '4' , photographed in a perpendicular to direction to '3', and at some distance from it, is the lower NW end of the north face of the bridge, which on the intact machine was mounted just above, and only a meter away from the track guide. Indeed the video of '4' shows the flange through which this corner was connected to the frame piece that is/was mounted on top of the track guide (albeit the mounting flange now looks sadly beaten up, de-bolted and without its partner)

But I'd expect the bridge of the crane to run across the pool east-west, and so the arrow is pointing along that east-west span where the bridge (4) would be found. That may be all they're saying with the arrow, that "The bridge (4) is along here."

A question the map doesn't answer is: is the track guide (3) (which would be at an end) on the low or high end? Assuming, as size-logic would suggest, that the crane rests at around a 45˚ angle along the elevation axis. My sense is 3 is on the low end, and notice that the lighting on it is about the same as on the fuel rack (2). What I believe it be the trolley's upper deck is on the east side and thus should be on the high end of the crane and 3 on the west-side low end.

 

[MadderDoc]

Unit3 PCV leaks

The blue arrows in the hatch diagram below might be intended to indicate the leak routes of the unit 3 equipment hatch known or suspected at the time of the publication. In fact I can't imagine what else they could mean, considering the context.

It struck me suddenly, that this diagram combined with the blue arrows pretty much mapped my understanding of the scope video from the equipment hatch scope, now after many reviews. (I also smell a possible explanation why the scope operator appears to navigate the cylindrical room as if he had been there before.)

 

[MadderDoc]

But I'd expect the bridge of the crane to run across the pool east-west, and so the arrow is pointing along that east-west span where the bridge (4) would be found. That may be all they're saying with the arrow, that "The bridge (4) is along here."

I think, what they are saying with the arrow is that the photo has been taken in the indicated direction relative to the indicated cask area, i.e. towards east from that face of the cask area. And specifically it is from _outside_ the cask area area, if I haven't got this wrong, I translated me to that bit from one of the Japanese versions of that photo montage, which specified in the same manner that the photo of '3' has been taken towards south, and from _inside_ of the cask area). The gate in the SFP3 cask faces south in the only photo I have of it, so that fits , although one may wonder whether the cask area is still intact and good looking.

A question the map doesn't answer is: is the track guide (3) (which would be at an end) on the low or high end? Assuming, as size-logic would suggest, that the crane rests at around a 45˚ angle along the elevation axis. My sense is 3 is on the low end, and notice that the lighting on it is about the same as on the fuel rack (2). What I believe it be the trolley's upper deck is on the east side and thus should be on the high end of the crane and 3 on the west-side low end.

I wouldn't dare much of a prediction on where the different parts of the FHM are hiding, It has suffered way more damage and breakage than I imagined, after I stopped believing in ballistic FHMs :-) Even the long bridge -- which I previously felt had to be nearly indestructible, appears to have been split longitudinally, so there you may have it: those long beam constructions may be tic-a-toe in the pool. Then what would it mean what is high and what is low, if it is just a mess.

However, it remains likely, in my mind, that several parts of the trolley, (I harbour no hope whatsoever of finding it in one piece),ae in that part of the pool you've been doing much work on.

BTW, could what we are seeing there close under the surface be the _bottom_ frame of the trolley, that one with the wheels? I feel I have been everywhere else high and low on the FHM looking without finding a match, only this stout frame remains, it is so well hidden, that I can't see enough to dismiss it as a possibility.

 

[SpunkyMonkey]

The blue arrows in the hatch diagram below might be intended to indicate the leak routes of the unit 3 equipment hatch known or suspected at the time of the publication. In fact I can't imagine what else they could mean, considering the context.

Could the blue arrows indicate flow of water into the hatch passage? That might be why the blue arrows march downward to a low point. I seem to recall seeing that graphic in a document showing the points from which a Mark I can leak, but is the document pre-tsunami? If I recall, it was talking about hydrogen leakage, in which case it's not water leakage and it is indeed hard to understand the arrows.

Edit: Yes, the text on the graphic is talking about waterproofing, so the blue lines must be water flow. They give us some sense of interior shape.

It struck me suddenly, that this diagram combined with the blue arrows pretty much mapped my understanding of the scope video from the equipment hatch scope, now after many reviews. (I also smell a possible explanation why the scope operator appears to navigate the cylindrical room as if he had been there before.)

Possibly the apparent structural complexity indicated explains the impression of suddenly seeing a 'new room' as the radiation snow went bannans. Maybe that 'room' is the low 'trough' at the floor that . But it's not perfectly clear what the objects outlined in the schematic would look like in 3d space.

That the radiation snow went nearly to a blizzard when it hit the 'new room' is a clue. The camera lens may have faced a direct line toward the PCV and/or was near only metal shielding meaning near the hatch's metal wall between passage and PCV interior. Or the camera might have come into proximity with contaminated water as the blizzard set in. It seems like almost the second the camera hit the blizzard zone, the cameraman hightailed it out of there!

 

[westfield]

I see what you mean, it also thought it could be more instructive. But the intent of the arrow to mislead is plausibly deniable. The arrow points as best it can to an object that is not visible in the drawing.



Neat. See that is more instructive! Attached is a suggestion for modification of the markup of unit 3 added x-beams, as I think they are at that end of the bridge.(Lest it might mislead into thinking you've seen more of the length of the bridge in that video, than you actually have.)

"Misleading" might have been too strong a word yes.

Regarding the U3 diagonal bracing - yes, your bracing detail better reflects how it actually is.

 

[westfield]

The blue arrows in the hatch diagram below might be intended to indicate the leak routes of the unit 3 equipment hatch known or suspected at the time of the publication. In fact I can't imagine what else they could mean, considering the context.

<snip>

(I also smell a possible explanation why the scope operator appears to navigate the cylindrical room as if he had been there before.)

It does seem to indicate the leak path. And now I'm wondering why they call that step thing "scaffolding".

Another diagram related to PCV hatch repair - without the step.

If it was welded in there it would be quite a task to cut it out for this idea to work.

(EDIT, sorry the following part was meant for spunky )

Also, you mentioned earlier that you thought perhaps the ugly rusty wet stain is the transition from concrete to the steel "step". I'm not sure. I would have thought that transition would be in line with the transition from rectangle to round. If that's the case then hasn't the camera has gone well past that point when it encounters the ugly rusty wet stain?

I really cannot understand why Tepco could not have used a better light source in there to shoot that video.

Re - operator knowing where to point the camera. I imagined they may have done a trial run at unit 5. Re - camera type, again , I was thinking they may have used the same type of "endoscope" camera they used for the unit 2.

 

[tsutsuji]

Cf this diagram,

The diagram with blue arrows is from http://www.meti.go.jp/english/earthquake/nuclear/decommissioning/pdf/20120315_02_004.pdf page 5/19.

But where did you find the diagram without blue arrows and with dimensions ?

http://www.tepco.co.jp/fukushima1-np/images/c12304_5.jpg
Fukushima Daiichi unit 1, from http://www.tepco.co.jp/fukushima1-np/c12304-j.html

http://www.tepco.co.jp/fukushima1-np/images/b13201_6.jpg
Fukushima Daiichi unit 3, from http://www.tepco.co.jp/fukushima1-np/b13201-j.html

http://www.tepco.co.jp/fukushima1-np/images/cb2006_3.jpg
Fukushima Daiichi unit 3, from http://www.tepco.co.jp/fukushima1-np/cb2006-j.html

http://www.tepco.co.jp/fukushima1-np/images/b13500_05.jpg
Fukushima Daiichi unit 3, from http://www.tepco.co.jp/fukushima1-np/b13500-j.html

And now I'm wondering why they call that step thing "scaffolding".

Perhaps because they don't know that it is called a "step" in English. I wish I could find a Japanese version to know how they call it in Japanese. There is one word in Japanese, 足場 litterally "foot-place". My dictionary translates it as "scaffolding, footing, foothold, beachhead"

 

[Rive]

... foothold...

Very thanks for the pictures.

On the first attached picture I've marked the area which can be that 'foothold', and a line on the containment wall, which I think can be identified on the video.

I think the device used was an endoscope taped on a stick, which limits the accessible area: an assumed accessible area is marked on the second picture. The area applies also to the ground side, but that part is crowded.

 

[westfield]

The diagram with blue arrows is from

<snip>

Perhaps because they don't know that it is called a "step" in English. I wish I could find a Japanese version to know how they call it in Japanese. There is one word in Japanese, 足場 litterally "foot-place". My dictionary translates it as "scaffolding, footing, foothold, beachhead"

The PCV Equipment hatch images are a very helpful find tsutsuji, thankyou.

Re - translation of "scaffolding. Ok, thanks again. I had that feeling it was a translation thing but I also wondered if it also indicated a temporary item.

Edit : If I may asnwer on behalf of madderdoc who first linked it - the PCV equipment hatch image without the blue lines is here at METI

 

[tsutsuji]

Edit : If I may asnwer on behalf of madderdoc who first linked it - the PCV equipment hatch image without the blue lines is here at METI

Can you please check again and tell which page number. Because this is the same pdf where I find the picture with blue lines (page 5/19).

I found the Japanese version of the Toshiba/Hitachi-GE/Mitsubishi Heavy Industries document with the blue lines : http://www.meti.go.jp/earthquake/nuclear/pdf/120227_01h.pdf (it is from the 27 February workshop: https://www.physicsforums.com/showpost.php?p=3787196&postcount=12416 ). The Japanese wording for the step is 常設足場 : permanent/normally installed step/foothold.

 

[SpunkyMonkey]

Sfp3 fhm

Here's a collage from this SFP3 video. I see what I think may be railing with metal fencing from the trolley, as pointed to on the right. And what might be the bottom of the trolley platform just above / beside the smashed-down crane bridge.

Any ideas on what's the large flat object that's smashed down across the crane's bridge? This is a pretty dramatic aspect. An easy guess is that it's a panel of the exterior wall. But it's difficult to understand why it would be there, since I believe most of the upper-deck wall panels got blown outwards and turned to rubble. So why, if it is a wall panel, would a wall panel be found on the north end of the pool? But if it's not a wall panel, what the heck is it? It seems to big to be the trolley. Perhaps some east-side wall panels fell inward. And yet there seems to be other large objects on top of this possible 'wall panel'. What a mess to figure out!

 

[SpunkyMonkey]

http://www.tepco.co.jp/fukushima1-np/images/cb2006_3.jpg
Fukushima Daiichi unit 3, from http://www.tepco.co.jp/fukushima1-np/cb2006-j.html

Great photos tsutsuji, thanks!

The probe camera makes the passageway seem much longer than it is. Curiosity, seeing the hatch passage better at the moment only makes me more confused about the video therein .

 

[MadderDoc]

Some interesting stuff there.
http://www.tepco.co.jp/en/nu/fukushima-np/roadmap/images/m120314_02-e.pdf

Sometimes looking at this stuff, I wonder if it in the end will be the data that validates the model or it will be the other way around. Or, perhaps, they might come to be seen as validating each other. However, to be fair not likely as all gigo. Data may be inaccurate, but the data sets do seem to contain information. Similarly, the models may not reproduce reality, or data, on all accounts, but they also do not seem outrageously detached from it.

An interesting example fom that presentation is the attempt to reproduce the pressure data of the PCV of unit 3. The natural trend for this parameter during the accident was to increase, by the accumulation of decay heat. By interventions, such as PCV cooling, or venting of steam from the PCV, that trend could be temporarily reversed, only to have the system picking up pressure again, when cooling, or venting was aborted.

The start of such downtrend episodes are neatly and appropriately presented in the diagram below, where the blue arrows are coming _down_, while their abortion, such as to go back to an increase of pressure is marked with the blue arrows coming _up_. And although arrow text is in Japanese, it is all about vents, their start and stop, respectively. When the occurence of vents are considered model assumptions the text ends with two glyphs parentesized, saying 'assumed' in Japanese. Those unmarked would then be those considered by the modellers to be factually known.

I can see there is some issues still to be resolved.

It is impressive to see how the model manages to distance itself from the Unit 3 explosion:

- First, the model starts out a S/C vent in the early morning of March the 14th, when data says nothing was vented.

- Then, at 11.01, at the time of the explosion, the model has nothing relevant happening, nothing worth a blue arrow -- while the data says a sudden major vent occurred.

-Finally, when data says the reactor picked up pressure some hours after the explosion, the model is let to assume the S/C vent it started in the morning has now been stopped.

Whilst I do not rule out the possibility of substantial quantities of fuel remaining in RPV at reactors 2 & 3, I think they are well aware that their analysis in this regard is probably out of whack with reality.

Yes, agreed. Perhaps it will be in the next version.

 

[SpunkyMonkey]

The gate in the SFP3 cask faces south in the only photo I have of it...

I don't understand what the SFP cask is, can you show that photo? Is it a fuel rack? I thought they eventually put fuel in dry casks, but I didn't know there are casks in the pool but have seen this noted here and there w/o imagery.

BTW, could what we are seeing there close under the surface be the _bottom_ frame of the trolley, that one with the wheels? I feel I have been everywhere else high and low on the FHM looking without finding a match, only this stout frame remains, it is so well hidden, that I can't see enough to dismiss it as a possibility.

Did you have in mind the thing I point to in my collage above as the trolley's base frame? It's not a perfect match for anything caught in the limited pre-tsunami imagery we have, but it's intuitively close. Now more than ever I agree with being confused as heck about where the FHM parts are. I still these parts have strong signals of being the upper deck, but how what looks like the bottom frame of the trolley can be deep down, but the upper deck above water. I just have to shrug my shoulders and say WTF?!

Certainly the FHM in Unit 3 took a horrendous beating!

 

[MadderDoc]

Great photos tsutsuji, thanks!

The probe camera makes the passage way seem much longer that it is. Curiosity, seeing the hatch passage better at the moment only makes me more confused about the video therein .

OK, so using measures from the diagram, now with regained trust from those fine photos, we have this cylindrical room of the hatch clearly defined. Geometrically, it is a cylinder of height 0.90 m. and diameter 3.050 m, lying at its side, and it has a horizontal insert to produce a platform, which according to the diagram is at a height of 0.385 above the lowest part of the cylinder. And with a bit of math .. inside he hatch we'll have approximately 7 m2 of hatch inner plate to potentially look at, about 8 m2 cylindrical wall, and 1.8 m2 floor platform. Most of which, according to Tepco, we have not seen in the video, although again according to Tepco we do see parts of the platform, or floor.

Also, I am pretty sure, we see parts of the cylindrical wall as well as parts of the inner plate. Starting with the inner plate, we see it most closely in connection with the filament like artefacts. The inner plate presumably has been painted with the same paint as the rest of the room but it has degraded differently due to heat, presumably. From there we also see the inner plate meeting the wall and/or the floor (I believe we see examples of both). One might expect a similar peel off of paint at the walls and perhaps at the platform close to the inner plate, but wet corrosion there steals the show. We see a patch of something looking as cracked steel, all rusted up and wet, I believe that is on the floor, but it cannot definitely be said to be a crack, it could be just a bad wet rust problem looked upon up close. Alien looking stuff, for sure.

The slit at the floor between the platform and the inner plate produces a narrow trench, where water from a leaking flange would run into and accumulate, connected to the trough like cavity under the platform, where water would similarly accumulate. The scope does not enter the latter cavity, but it appears to have high interest in the corrosion along the slit at the inner plate. My 0.02.

Edit: corrected depth of hatch 0.4 m --> 0.9 m and affected areas.

 

[westfield]

Can you please check again and tell which page number. Because this is the same pdf where I find the picture with blue lines (page 5/19).

<snip>

. The Japanese wording for the step is 常設足場 : permanent/normally installed step/foothold.

Why yes it does have the blue marking, my apologies for the wild goose chase.
I've subsequently discovered that when the image is extracted from the PDF it has no blue marking on it.

At the risk of posting the same thing again, click on the thumb for the extracted image at it's best resolution without markings:

 

[MadderDoc]

I don't understand what the SFP cask is, can you show that photo? Is it a fuel rack? I thought they eventually put fuel in dry casks, but I didn't know there are casks in the pool but have seen this noted here and there w/o imagery.

Sorry, I meant to write 'cask area' It is a box like area in the corner of the pool, which is used for transporting 'stuff' in and out of the pool, such that the stuff is always kept either under water, or inside a cask, for radiation shielding. During the operation the cask is placed in the cask area.

The photo I refer to is this one

Did you have in mind the thing I point to in my collage above as the trolley's base frame? It's not a perfect match for anything caught in the limited pre-tsunami imagery we have, but it's intuitively close.

Edit: No, not that one, I have no idea what those fragments are, FHM parts is fair game.

The trolley deck I am talking about is that one the video you made of, the thing looked at from the concrete pump over the pool. It has several platforms, the main structure of most can be made out so-and-so, at least enough to make one doubt that they could be what we see in that position of the pool.
The waggon the machine with the grabbler is traveling on east west over the pool is however just too much out of sight in photos for that. It would have a stout structure, and it would have cut-outs for mounting wheel boxes and such underneath, all of that could have come off so there remains only the basic frame of that waggon. So I thought maybe that could be it.

 

[SpunkyMonkey]

OK, so using measures from the diagram, now with regained trust from those fine photos, we have this cylindrical room of the hatch clearly defined. Geometrically, it is a cylinder of height 0.40 m. and diameter 3.050 m, lying at its side, and it has a horizontal insert to produce a platform, which according to the diagram is at a height of 0.385 above the lowest part of the cylinder. And with a bit of math .. inside he hatch we'll have approximately 7 m2 of hatch inner plate to potentially look at, about 3.5 m2 cylindrical wall, and 0.8 m2 floor platform. Most of which, according to Tepco, we have not seen in the video, although again according to Tepco we do see parts of the platform, or floor.

Revisiting the video with the photos now in mind it's pretty clear. Obviously westfield was right that the wall is curved, but moreover that its curvature probably explains the wall / floor impression. The camera enters at the curved painted wall with the leaky flange (slime trail) in sight then probably scrolls down and left to the concrete floor, in which case the moment of footage Tepco calls floor is floor, which brings things to right.

Now I'm wonder if the 'new room' is looking back at the back side of the plug. Notice that the trough there seems to be flat and the 'change of scene' could be the camera quickly panning 180˚. That trough is not the slime trail.

EDIT: or the 'new room' might be looking almost straight up toward the hatch-door seam. Just not sure.

 

[tsutsuji]

I've subsequently discovered that when the image is extracted from the PDF it has no blue marking on it.

Thanks for solving the mystery.

it is a cylinder of height 0.40 m. and diameter 3.050 m,

Does that mean that the x and y-axis scales are different ?

Also on the other diagram here : http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_120419_03-e.pdf the grey part seems to be about one third of the diameter (it looks like 1 m instead of 0.40 m). Don't you think it could be "900" mm (0.90 m) instead of 0.40 ?

 

[westfield]

<snip>

During the operation the cask is placed in the cask area.

The photo I refer to is this one
http://192.168.168.11/daiichigrab/unit3/f1-27.jpg

<snip>.

MadderDoc could you check that Cask area image link - it's not working for me and it appears to point to a private IP address range.

 

[Rive]

Still about the shield plug video: the spherical distortion and the shaking makes it a mess. After removing them, it's much more better (the result is under it's way up to the youtube). I think the rusty-wet part is where the internal steel door meets its frame. The falling paint (?) chips are removed from the steel door.

Ps: the video is available here:

At 1:09 the cam enters the circular area of the hatch, and around 1:13 it bangs to the steel door and stops moving at that direction. Around 1:20 the door and frame fitting can be seen first time on the upper-left corner: the concrete there has a strange bluish colour, maybe becouse of the temperature?

Around 1:25 the cam turning and sliding down on the circular part. At 1:55 it's 'climbing' upward on the door: you can see that the upper part of the image is moving strange: it's because the upper part is actually the vertical door, while a lower parts are the almost horizontal part of the circular opening. The deshaker does not handles well when the different parts of the image has different relative speeds.

Around 2:20 the cam is moved upward, facing right and checking the fitting between the door and the frame. This is the part when the small chips flying.

After that not much left: the floor with wet parts can be seen for a moment as the cam is pulled out. Then the run for the low dose.

I think that's it, more or less.

Ps.: it's worth to watch the video at highest resolution and full screen.

 

[MadderDoc]

MadderDoc could you check that Cask area image link - it's not working for me and it appears to point to a private IP address range.

Right. Here it comes:

 

[westfield]

Here's a collage from <snip>
I see what I think may be railing with metal fencing from the trolley, as pointed to on the right.

<snip>. What a mess to figure out!

Re - the mesh you mention - While it's all over the place in the SFP -
given that we do know we are looking at the end of the "Catwalk" that runs along the northern length of the FHM bridge it may be more likely it's mesh from the "catwalk" rather than the FHM proper, the trolley part.

I look at it as the FHM & the FHM bridge as I'm not familiar with what they are called.
They probably have cute nicknames in the business.

I need to look at that clip again - I've only looked at the truss\driveshaft so far.

 

[westfield]

Right. Here it comes:

<image snipped>

Is that the right image? I don't see a cask loading area there. Great piccy though.

Here's a picture of one prepared earlier by tcups (not a fukushima one)

Or here in the SE corner of the pool if this was Unit 3

 

[MadderDoc]

<..> Don't you think it could be "900" mm (0.90 m) instead of 0.40 ?

You are absolutely right. Thank you.

 

[MadderDoc]

Or here in the SE corner of the pool if this was Unit 3
http://s1185.photobucket.com/albums/z360/fukuwest/misc/?action=view&current=1312012042605_28_05.jpg

Yes, 'tis, but that is not where the cask area is.

I have attached a marked up version of that other photo, which I believe is pointed along the west wall of the SFP3 towards its NW corner. Marked up is the outline of what I believe is the gate to the cask area. My clue was the horizontal X structure at its bottom which I see as the cask support. X always marks the spot :-)

It got clinched only recently, when we were told in no uncertain terms by Tepco that the cask area is in the NW corner -- which was where I had this photo figured out to be from, from combining information from other photos of the pool taken during the MOX refueling & a previous photo tour.