Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[SteveElbows]

However, ever since, it's been the higher estimate of the number of assemblies in the pool that has kept popping up, also in data released directly by Tepco, and consequently my confidence in having seen them all during the mapping of SFP4 has eroded. Otoh, I still can't see where the extra assemblies could be hiding in the pool. I would be happy to have my results corroborated or rejected by another mapping attempt made independently from my own. Absent that, I must say that I cannot exclude based on my mapping that some assemblies may still be in the reactor pit.

The temperatures shown on the thermal images were not generally very high really. So I am not really sure that we have clear signs of a big source of heat in the reactor area, but I admit some of the thermal images still interest me in this regard. Is it possible that we are just looking at the heat of steam that has blown in a northerly direction as it rises up from the pool? Or we are looking at water that is in the pit & reactor well area, but is not really very hot?

I have trouble imagining some fuel still being in reactor area, because diagram from the other day that showed work to inject water into reactor well & pit areas, seems to suggest that the core shroud has been removed and placed in the pit. I don't imagine them having any fuel in the area if shroud has been removed. It would be helpful if we knew more about the exact stage the shroud replacement work was at when disaster struck.

 

[SteveElbows]

Thanks Steve, perhaps this is where it's coming from, whatever it is. I agree the machine translation is probably not good enough to decide what that is, but it seems clear at least that in the timeline for unit 2 in this document, all reference to the unit 3 explosion has not been omitted. This is unlike the unit 2 timeline reproduced in the appendix to the Japanese government report to the IAEA, which in comparison appears to have been scrubbed of reference to unit 3. Otherwise, the two timelines appear to be quite similar at about this time between March 13th and 14th.

While we are waiting for full translation, here are some interesting press stories based on the document:

http://www.yomiuri.co.jp/dy/national/T110619002601.htm

http://search.japantimes.co.jp/cgi-bin/nn20110619x2.html

There are some interesting details covered by these stories, including the venting problem and some other things that went wrong as a result of explosions.

 

[zapperzero]

The temperatures shown on the thermal images were not generally very high really. So I am not really sure that we have clear signs of a big source of heat in the reactor area, but I admit some of the thermal images still interest me in this regard. Is it possible that we are just looking at the heat of steam that has blown in a northerly direction as it rises up from the pool? Or we are looking at water that is in the pit & reactor well area, but is not really very hot?

It could even be heat from nuclides in the RPV walls and shroud, for all we know.

 

[SteveElbows]

It could even be heat from nuclides in the RPV walls and shroud, for all we know.

Any ideas how we learn more about this issue in theory? I have no proper sense in my mind of how much heat something like the shroud may create months after shutdown.

 

[zapperzero]

Any ideas how we learn more about this issue in theory? I have no proper sense in my mind of how much heat something like the shroud may create months after shutdown.

I'm under the impression that some of the posters here may have first-hand experience with such issues...

 

[jim hardy]

to (was it M'doc?) thought about explosion below decks

Did something change atop unit 3 in the first week ?



.....24(? i think) March..........16 March

(ignore the label - it's nobody here.)


telephoto compression distorts perspective, so count rafters on the right side of main beam.

 

[zapperzero]

to (was it M'doc?) thought about explosion below decks

Did something change atop unit 3 in the first week ?



.....24(? i think) March..........16 March

(ignore the label - it's nobody here.)


telephoto compression distorts perspective, so count rafters on the right side of main beam.

Are you sure you're looking at the same section of beam?

 

[robinson]

Yes.

 

[biggerten]

While we are waiting for full translation, here are some interesting press stories based on the document:

http://www.yomiuri.co.jp/dy/national/T110619002601.htm

http://search.japantimes.co.jp/cgi-bin/nn20110619x2.html

There are some interesting details covered by these stories, including the venting problem and some other things that went wrong as a result of explosions.

Man. The guy gets the battery from his car to power the valve to release pressure so they can inject water in No. 3. While nuclear reactor buildings explode from time to time. And earthquakes. In the dark.

Desperate measures in desperate times. I thought my job was hard. Hah! I am humbled. These guys are true heroes.

 

[razzz]

In the YouTube http://www.youtube.com/watch?v=lJjbNw07OUA" just after 7 minutes he says the shroud replacement was complete in Unit 4, according to his GE connections.

 

[SteveElbows]

to (was it M'doc?) thought about explosion below decks

Did something change atop unit 3 in the first week ?

(ignore the label - it's nobody here.)


telephoto compression distorts perspective, so count rafters on the right side of main beam.

The red rings in this photo are simply wrong and misleading.

The photo on right actually shows the section of beam going all the way to the east end wall, not just to the position indicated by red ring in the left photo. The photo on right is shot from a lower angle, causing this mistake to be made.

Look at the more noticeable beam that goes south (going left on photo) and is near the bottom of the picture on the right. This is the same beam that is near the bottom of the left picture, not the one half-way up.

If you already know this, and were advising us to ignore the red rings, then I don't know what else is supposed to be different in these two pictures, nothing has changed at all.

Edited to add a picture showing how things actually line up, since I am not sure my words made sense.

 

[etudiant]

An interesting take on the prospects for nuclear in China.
A senior researcher of the NDRC (National Development and Reform Commission) was interviewed at some length by 'Business China' here: http://en.21cbh.com/HTML/2011-5-11/yOMTc1XzIxMDEyOA.html

Takeaway was: nuclear is less bad than the alternatives and besides, Japan relied on antiquated reactors, badly located.
There was a nice dig at the safety of large dams in the interview, a gutsy move given the political support lavished on the Three Gorges project.

 

[jim hardy]

""'If you already know this, and were advising us to ignore the red rings, then I don't know what else is supposed to be different in these two pictures, nothing has changed at all."""

i do get frustrated by my clumsiness with "Paint" .

Indeed as you point out the left red ring should be dragged down until it grazes the east end of the beam, as does the right red ring. They are misaligned.

the angle of sunlight is different between the photos so illumination of the floor below the beams changed..

The feature i am interested in is not the beams but something underneath them, namely that black circle inside the ring in Mar 16 photo on right.
To me it looks like a hole in the deck below.
It is not visible in later photos.
It does show briefly in a March 15th helicopter video as mentioned a few pages ago..
around 1:10
so if it's an optical illusion it was there on two days.


What i was after is opinion on whether the black circle looks to anybody else like a hole in the deck. I sometimes suffer from what Mark Twain called "excess of imagination."
There seems to be plenty of photo expertise here. Perhaps somebody has another early photo or some enhancement tools that'd nail it yea or nay.

original is , again, at
http://cryptome.org/eyeball/daiichi-npp3/daiichi-photos3.htm
twenty-third one down.


jh

 

[Borek]

Catching up to congratulate you for being the poster of the ten thousandth post to this thread!

This is not the first time we hit 10k, however, some posts were deleted/moved to other threads.

 

[MadderDoc]

<..>
Did something change atop unit 3 in the first week ?
.....24(? i think) March..........16 March
<..>

March 24th, yes.

Water was replenished to the pool over that period, so that's something that changed drastically, but probably not what you are hinting at.

I've found no evidence of structural changes in the remains of the roof metal structure since the explosion on March 14th, and also not between March 16th and 24th. I don't think there has been any such changes. If you've counted different number of beams in these two photos, there's probably one that has been missed. The slightly different angle could well make the beams closest to the camera hard to detect in these photos, then try counting from the other direction. I think you will find everything matches up.

Compared to the March 16th photo, the photo from March 24th features a readily apparent dark discoloration of beams, girders and pillars, assumedly from the recent fire on the evening of March 23rd:

 

[WhoWee]

Man. The guy gets the battery from his car to power the valve to release pressure so they can inject water in No. 3. While nuclear reactor buildings explode from time to time. And earthquakes. In the dark.

Desperate measures in desperate times. I thought my job was hard. Hah! I am humbled. These guys are true heroes.

Absolutely!

 

[MadderDoc]

<..>
The feature i am interested in is not the beams but something underneath them, namely that black circle inside the ring in Mar 16 photo on right. To me it looks like a hole in the deck below.
It is not visible in later photos.

I too can make it look like a circle, but I am pretty certain it's an illusion, To make it look like a circle I need to blend in certain dark areas which via other photos can be identified as parts of material objects, not holes.

It does show briefly in a March 15th helicopter video as mentioned a few pages ago..
around 1:10
so if it's an optical illusion it was there on two days.

The date attribution is wrong for this video. Actually there are two videos there combined, including the video from which your photo was taken, both videos are from March 16th.

 

[Jorge Stolfi]

The temperatures shown on the thermal images were not generally very high really. So I am not really sure that we have clear signs of a big source of heat in the reactor area.

Perhaps it is just heat from the sun that is stored in the water during the day and released at night.

 

[MadderDoc]

The temperatures shown on the thermal images were not generally very high really.

The heat signature from that part of the building has generally been about 30^oC, or appr. 30^oC above ambient. See:
http://gyldengrisgaard.dk/fuk/thermal/thermala.html

So I am not really sure that we have clear signs of a big source of heat in the reactor area, but I admit some of the thermal images still interest me in this regard. Is it possible that we are just looking at the heat of steam that has blown in a northerly direction as it rises up from the pool? Or we are looking at water that is in the pit & reactor well area, but is not really very hot?

The signature indicates that going to sleep there on a stretcher across the reactor well on a freezing cold night during March or April, would have involved sleeping in a tropically warm and steamy environment at 30+^oC. Certainly that needs an explanation.

 

[clancy688]

Sounds probably silly, but...

What's with heat transfer from the pool to the RPV? Even if the gate's inteact, it should conduct heat.

So if there's 90+ degrees on one side and 20 degrees on the other, the other side is probably getting hotter.

Catching up to congratulate you for being the poster of the ten thousandth post to this thread!

But we're still only the second largest thread in PF. https://www.physicsforums.com/showthread.php?t=63689" thread has 10560 posts.

400 posts to go for number one.

 

[MadderDoc]

Perhaps it is just heat from the sun that is stored in the water during the day and released at night.

No, that's not possible. I foolhardily got in early summer mode and introduced a flock of reasonably cold resistant fish in my pond in late April, observing that a series of sunny days had managed to drive the water up to 15^o. During the night weather changed, temperature dropped to the freezing point, and next morning the pond stood at 3^o and not a fish was alive. If only it were so easy to stack solar heat for the night during the cold spring of the north temperate zone. If only.

 

[MadderDoc]

Sounds probably silly, but...
What's with heat transfer from the pool to the RPV? Even if the gate's inteact, it should conduct heat.
So if there's 90+ degrees on one side and 20 degrees on the other, the other side is probably getting hotter.

Surely that's something that could be estimated. The estimation should take into account not only the heat gain through the relatively small gate area, but also the heat loss through the disproportionately much larger remaining area interfacing with a colder atmosphere and supposedly colder reactor and containment structures.

 

[jim hardy]

"""I too can make it look like a circle, but I am pretty certain it's an illusion,...""

thank you, that's what i was after - another opinion on the dark circle.

i can live with "it's ambiguous".

Indeterminate is after all a valid state.

thanks for the input.

 

[MadderDoc]

"""I too can make it look like a circle, but I am pretty certain it's an illusion,...""
thank you, that's what i was after - another opinion on the dark circle.
i can live with "it's ambiguous".
Indeterminate is after all a valid state.
thanks for the input.

Personally I wouldn't say it is ambiguous. During the flight the video camera scans across the area in question, and in only a few frames there's this appearance of a circle. Skipping forward and backwards frame by frame It seems clear to me this effect is caused by the camera's looking through changing 'windows' in the rightmost steam plume caused by its swirling motion in the wind. It is easy enough to select a few frames in which it looks like there is a circle, but that does not mean one can cast away the great majority of frames in which nothing like a circle appears and it rather looks like there is a duck, a frog, Aladdin's jinni or something else or nothing but steam there.

 

[joewein]

What's with heat transfer from the pool to the RPV? Even if the gate's intact, it should conduct heat.

Yes, but until recently the water level on the reactor pit side of the gate was low, until they realized this removed radiation shielding for the steam dryer and cut-up shroud and topped it up.

While the water was low only the lower portion of the gate area would have transferred heat and the reduced water depth would have reduced convective transfer.

In the YouTube http://www.youtube.com/watch?v=lJjbNw07OUA" just after 7 minutes he says the shroud replacement was complete in Unit 4, according to his GE connections.

I noticed that too and then I saw someone post here that they were 5 months into a 10 month shroud replacement job. Unit 4 had been shut down either on November 29 or 30, depending on the source. The 10 months overall seem plausible, given it took more like 15 months the first time they replaced a shroud in Japan, but end of November to mid March is only 3 1/2 months.

TEPCO says the shroud in the tool bay was cut, so presumably that's the old one that had been cut up under water using plasma cutters and lifted out.

Toshiba writes that they surface-decontaminate all the metals using oxalic acid before starting the replacement. I don't think there can be a huge amount of decay heat from activated isotopes in the RPV steel or there would be a lot of gamma too and people couldn't be working in there during the repairs.

 

[jlduh]

Sounds probably silly, but...

What's with heat transfer from the pool to the RPV? Even if the gate's inteact, it should conduct heat.

So if there's 90+ degrees on one side and 20 degrees on the other, the other side is probably getting hotter.
But we're still only the second largest thread in PF. https://www.physicsforums.com/showthread.php?t=63689" thread has 10560 posts.

400 posts to go for number one.

Not all data in this other long thread come from peer reviewed articles, it seems

Being more serious, it seems they are moving a huge crane close to Building N°1, it's currently on Tepco webcam:

http://www.netimago.com/image_213177.html

http://www.netimago.com/image_213178.html

 

[joewein]

The crane at unit 1 most likely is for putting up the metal frame and polyester cover around the damaged building. Preparation work for it started on May 13, according to TEPCO.

Here's their plan:
http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110614e17.pdf

Recently TEPCO's workers have been practicing assembling and disassembling the cover at Onahama port. Assembly at Fukushima 1 unit is scheduled after disassembly is finished at Onahama.

 

[etudiant]

Now appear to have a pump unit on reactor 1. Photo survey or water injection? Anyone have any insight?

 

[joewein]

According to TEPCO, pool water injection is now done via the pool cleaning and cooling system at all units (unit 4 having been the last one to make the switch from concrete pumps on June 16).

I don't think they'll cast concrete foundations for the cover, otherwise they didn't have to go for this lightweight design. They'll use a more robust structure for the next layer, whenever that will arrive.

Camerawork is a good guess.

Oops, it's gone again!

EDIT: The crane is too small for erecting that cover, but it may be used for clearing the place for the other one.

 

[tsutsuji]

The crane at unit 1 most likely is for putting up the metal frame and polyester cover around the damaged building. Preparation work for it started on May 13, according to TEPCO.

It could be the crane assembled by the worker who removed his mask for smoking :

According to TEPCO, the worker in his 50s was helping put together a crane on the morning of June 15 as part of preparations to build an enclosure around the plant's No. 1 reactor.
http://mdn.mainichi.jp/mdnnews/news/20110616p2a00m0na008000c.html