Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[mscharisma]

The NRC is winding things down in Japan...

"The United States Nuclear Regulatory Commission said on Monday that its 24-hour operations center had stopped monitoring the nuclear reactors at the Fukushima Daiichi plant because the situation there had improved. “The conditions at the Japanese reactors are slowly stabilizing,” said William Borchardt, the agency’s chief staff official."

http://www.nytimes.com/2011/05/17/world/asia/17briefs-Fukushima.html?_r=1

Sayonara!

Not to get his thread off track from the technical to the political side of things, I'd still think it important to point out that the NRC typically takes a very pro-nuclear stand and, at least in public, minimized the accident from day one. They have consistently used terms such as "stable" or even "recovering." The only assessment of the accident and its potential implications that was less than positive was the confidential(!) internal document that leaked to the press (linked here a few pages back). Personally, I trust the knowledgeable and expert opinions on this thread by far more than anything publicly declared by the NRC.

 

[etudiant]

Not to get his thread off track from the technical to the political side of things, I'd still think it important to point out that the NRC typically takes a very pro-nuclear stand and, at least in public, minimized the accident from day one. They have consistently used terms such as "stable" or even "recovering." The only assessment of the accident and its potential implications that was less than positive was the confidential(!) internal document that leaked to the press (linked here a few pages back). Personally, I trust the knowledgeable and expert opinions on this thread by far more than anything publicly declared by the NRC.

As noted, the NRC is scaling back its presence in Japan on the basis of an improved outlook.
However, afaik this is the most positive comment the NRC has made on this situation to date.
Previously, the NRC comment I recall were quite circumspect.
I particularly noted that the NRC head previously described the situation as static, rather than stable. That seemed a very exact choice of words, which correctly described the situation. The NRC did a very fine job in this situation, at least imho. They did not sugar coat when they publicly suggested that Americans should stay 80km away from the plant, while the host country was telling its people 30km.
In light of subsequent disclosures, their advice looks pretty good.

 

[sp2]

As noted, the NRC is scaling back its presence in Japan on the basis of an improved outlook.
However, afaik this is the most positive comment the NRC has made on this situation to date.
Previously, the NRC comment I recall were quite circumspect.
I particularly noted that the NRC head previously described the situation as static, rather than stable. That seemed a very exact choice of words, which correctly described the situation. The NRC did a very fine job in this situation, at least imho. They did not sugar coat when they publicly suggested that Americans should stay 80km away from the plant, while the host country was telling its people 30km.
In light of subsequent disclosures, their advice looks pretty good.

Yeah, that advice looks pretty good (and makes them look a lot more responsible than their Japanese counterparts), but this statement now (basically that 'we're packing up and heading home because everything's fine now') looks shockingly stupid and irresponsible, don't you think?

(And *unbelievably* badly timed.)

 

[mscharisma]

As noted, the NRC is scaling back its presence in Japan on the basis of an improved outlook.
However, afaik this is the most positive comment the NRC has made on this situation to date.
Previously, the NRC comment I recall were quite circumspect.
I particularly noted that the NRC head previously described the situation as static, rather than stable. That seemed a very exact choice of words, which correctly described the situation. The NRC did a very fine job in this situation, at least imho. They did not sugar coat when they publicly suggested that Americans should stay 80km away from the plant, while the host country was telling its people 30km.
In light of subsequent disclosures, their advice looks pretty good.

You are right, the NRC has often spoken of a difficult and/or complex situation, but IMHO they have also too often been rather evasive. Without going into a full-blown analysis that is not appropriate in this thread anyway, I can only tell you that my general negative impression results from press briefings such as these:

White House press briefing with NRC, March 14
http://www.whitehouse.gov/the-press...ary-jay-carney-nuclear-regulatory-commission-

White House press briefing with NRC, March 17
http://www.whitehouse.gov/the-press...ary-jay-carney-chairman-nuclear-regulatory-co

You are also right that they have spoken of "static but not stable" on April 13. But nonetheless, there were also statements like these:
'Peter Lyons, Acting Assistant Secretary for the Office of Nuclear Energy at the U.S. Department of Energy, said, "Current information suggests that the plants are in a slow recovery from the accident. However, long-term cooling of the reactors and pools is essential during this period and has not been adequately restored to date to the best of my knowledge. A massive clean up effort obviously remains for the future."Lyons testified before the U.S. Senate Committee on Energy and Natural Resources.
“And the situation in general continues to further stabilize, although there are many hurdles that remain," he said.' (March, 29: http://www.thejapannews.net/story/762319 )

But, I admit, it can very well be that I have an unjustified, overly negative impression. Thanks for having shared your view point and causing me to keep a critical eye on or even re-evaluate mine.

 

[I_P]

If you look through the charts posted here: http://fleep.com/earthquake/
you will see that what happened at unit 3 on the 20th had a significant impact on the radiation levels to the south of the plant. It also appears that the black smoke events over the next few days were also associated with increases in radiation. I have been assuming that TEPCO's lack of clarity about what happened during this period is due to their own confusion/lack of knowledge. The fact that unit 3's RPV dropped to atmospheric pressure on the 20th is a significant clue.

 

[mscharisma]

I can't remember if you all have this information already, but the attached document has location and numbers of fuel assemblies on page 4. Sorry if it's old info for you.

 

[GJBRKS]

I don't think, it is ruptured. Just a matter of perspective:

I think you are quite right , thanks

 

[MiceAndMen]

Yeah, that advice looks pretty good (and makes them look a lot more responsible than their Japanese counterparts), but this statement now (basically that 'we're packing up and heading home because everything's fine now') looks shockingly stupid and irresponsible, don't you think?

(And *unbelievably* badly timed.)

Assuming this refers to the NRC, I respectfully disagree. To say they are acting irresponsibly implies that they bear some duty to act responsibly in the first place. As far as I can see, they were there to advise the Japanese, not to assume responsibility for anything. It's not like they are running away from their duties.

 

[Rive]

I can't remember if you all have this information already, but the attached document has location and numbers of fuel assemblies on page 4. Sorry if it's old info for you.

Thank you for this document.

Statement of Lake Barrett at the Nuclear Energy Institute’s Used Fuel Management Conference, Baltimore, MD, May 2, 2011.

There is no mixed oxide (MOX) fuel in any pools, although some had been loaded in the Unit 3 core.

 

[~kujala~]

Everything else fine in #3 temperatures except those two RPV readings:

The other one is 258,6 degrees, 16th of May, 5:00 (second highest).
The highest has been 269,6 degrees, 15th of May, 14:00.

The other one is 267 degrees, 16th of May, 5:00.
The previous high was 262,7 degrees, 16th of May, 2:00.

http://www.tepco.co.jp/nu/fukushima-np/f1/images/032_1F3_05160600.pdf

 

[razzz]

Interesting read about the great quake and land movement both horizontal and vertical at the http://ex-skf.blogspot.com/2011/05/fukushima-i-nuke-plant-ground-may-have.html"

His conclusion:

Vertical: - 50 centimeters (it sank 50 centimeters)
Horizontal: 220 to 250 centimeters to the east.

I haven't read anything that said otherwise esp. parts of the island moving 8 feet to the east.

 

[artax]

First post, not a journo or troll, being an engineer just interested, please bear with me I have one question
I remember that in the Chernobyl incident that they tunnelled under the reactor core. Initially to install a large air conditioning unit. Then decided to fill it with concrete.To stop the corium core hitting water below which would have caused a very large explosion. How do this relate to this incident ?
God bless the miners that dug that "room"
tia

HEllo, Yes, the Russians learned a lot and should have been consulted earlier,... though as I understand it the mechanisms and type of cleanup needed are very different. There's a good vid on YT that says they eventually pumped Liq. N2 into the ground under the reactor,... and the evaporating N2 gas "put the fire out"
The corium there seems to have melted the sand they poured on and it cooled and solidified before reaching water table...
However the Russians had an open reactor, on which to dump sand.
I think not knowing the state of the three CORES here is the main problem... How can you know what to do... I hope modern reactors have a radiation proof camera looking at the state of the core incase this happens again.

 

[artax]

Find attached photos from two angles of a cylindrical oject lying leaned to the roof wall of turbine building 3. Seen from the THawk angle, one can well interpret the object as being connected to the piping there, i.e part of the original installation, albeit somewhat damaged. However, seen from the west in a zoom from one of the herostratic high resolution photos, it can be seen that it is not mounted, but has crashed on top of the original pipe. It has not been possible for me to find any satellite photo from before the unit3 explosion showing this object. So, I am led to believe that this object could be one of the ballistic objects. I have no idea what it could be, and where it sat in the building before the explosion. No high hopes that anybody can identify it, there are few clues except shape and a peculiar coat it appears to have been lined with.

Hey Madder, the chances of a ballistic object landing in that configuration, parallel with anything and just a foot away from a wall,... and not deforming it's shape are quite frankly near zero.
C'mon... it was installed there before anything happenned.

 

[jlduh]

I think perhaps this chunk might be from the top level of panels. From the low position it would seem a big ventilator thing have miraculously escaped the collision. Against this thought speaks the apparent low grade damage to the pipe on which the chunk fell.

The more I look at unit 4, the more an impression forms of a building thoroughly filled with a mixture of hydrogen and air enough to cause a widespread deflagration, if not an explosion.

I've attached a frame from the THawk trip along the turbine buildings showing the chunk.

Well, i have to admit that the view from the THawk is kinda strange. The chunk has a very different appearence than on the other pictures I posted, where it looks clearly to be concrete, on this one it's not so clear but the rendering of the picture is bizarre. What is really surprising is the small amount of damages around or under it, like if it was delicately put there! Either it's heavy but was not falling but coming from not so far away, either it's light (but i doubt about it)...

Strange.

I put an other Hi RES image from south side (enlarged) and really from here it looks like a big chunk of concrete, very thick: compare with the height of one floor of the building, and this piece is even located further than the south wall (it'a at the level of the north wall), so because of perspective it's even a little bit bigger than it looks by straight comparison. One of the tubing is ruptured (the left one) as we see, but one would expect much more damage...

Of some interest also, an other quite big chunk of concrete (darker, greysish) sits at the top of the roof of reactor N°4, North side.

These two were not there after N°3 explosion on satellite image. So both come from N°4 explosion(s). Very strange positionning of the two ones.

If this is concrete, and specially the biggest one, where do we find such a big thickness of concrete in a reactor building ? (I attach blueprint of a reactor below) ?

http://www.netimago.com/image_200944.html

http://www.netimago.com/image_200945.html

 

[~kujala~]

Interesting read about the great quake and land movement both horizontal and vertical at the http://ex-skf.blogspot.com/2011/05/fukushima-i-nuke-plant-ground-may-have.html"


I haven't read anything that said otherwise esp. parts of the island moving 8 feet to the east.

I found an interesting site about building nuclear plants directly on bedrock:

http://www.chuden.co.jp/english/initiatives/eini_nuclearpower/enuc_earthquakemeasures/eear_bedrock/index.html

It says:

The amplification rate varies according to the type and topography of surface ground

It would be nice to know what is the amplification rate of mudstone. Is it the same as that of bedrock so practically Fukushima plants would be as safe as if they had been built inside bedrock? Other techniques can also be used, likely together with bedrock foundations:

In designing structures for earthquake resistance, one should find tie beams underground between the columns to transfer weight from one footing to another in the case of differential settling. Another option is to build a so-called floating foundation, where the building is essentially like a ship. The ground may move, but the building will move with it and the building internals (i.e. walls, columns, pipes, etc.) hopefully will not have much movement relative to each other. I think the latest design from Areva uses a floating foundation.

http://ex-skf.blogspot.com/2011/05/fukushima-i-nuke-plant-ground-may-have.html
(comments)

 

[SteveElbows]

Find attached photos from two angles of a cylindrical oject lying leaned to the roof wall of turbine building 3. Seen from the THawk angle, one can well interpret the object as being connected to the piping there, i.e part of the original installation, albeit somewhat damaged. However, seen from the west in a zoom from one of the herostratic high resolution photos, it can be seen that it is not mounted, but has crashed on top of the original pipe.

T-Hawk images seem to show that this was thick lagging that went round a pipe, something hit the end of it causing end section of lagging to crack and fall down.

The high res picture was taken from too great a distance to pick up on any of this detail.

 

[SteveElbows]

If you look through the charts posted here: http://fleep.com/earthquake/
you will see that what happened at unit 3 on the 20th had a significant impact on the radiation levels to the south of the plant. It also appears that the black smoke events over the next few days were also associated with increases in radiation. I have been assuming that TEPCO's lack of clarity about what happened during this period is due to their own confusion/lack of knowledge. The fact that unit 3's RPV dropped to atmospheric pressure on the 20th is a significant clue.

I am a little wary of the rises that are shown far away from the plant on that date, simply because they may have been caused by changing weather conditions which sent stuff in direction of Tokyo.

So I tend to go by radiation dose measurements from the site itself, which also rise over the same period. Shame there are some gaps in such data during this time, although I suspect that was inevitable given site evacuations that these smoke events & higher readings caused.

 

[jlduh]

Page 30 shows CAMS readings from the Unit 2 suppression chamber (B) from the middle of April till now. I cannot really pinpoint dates, but there are large peaks (up to 160 Sv/h) with a valley of about 40 Sv/h.

There seems to be a correlation with drywell temperature RPV (C):
http://www.ic.unicamp.br/~stolfi/EXPORT/projects/fukushima/plots/cur/plot-un3-full.png

Is this where the corium is, in the middle of the torus? Is it going critical some weeks?

Beware, you compare readings from Unit 2 S/C and drywell temp RPV for Unit 3...

 

[SteveElbows]

Lots of new images from site published today, I think as part of their roadmap update:

http://www.tepco.co.jp/en/news/110311/index-e.html

Most of the images I don't find very interesting, but there is also a 13 minute video showing a variety of scenes on site. They really have sprayed that anti-scattering agent all over the place.

The roadmap update isn't available in English yet but a quick look at the Japanese version suggests that this is as much about a desire to show all the 'progress' they have made, as it is a serious update of technical measures required.

 

[tsutsuji]

http://www.zakzak.co.jp/society/domestic/news/20110517/dms1105171643027-n1.htm tells the following : on May 15th boron was added to unit 3 but the temperature on May 16th is still high with 269°C instead of the required 100°C. A concrete wall is to be built surrounding underground floors to prevent contaminated water to leak into the Earth (it is not clear which units are concerned). Reactor buildings at all 4 units (1,2,3 & 4) will be reinforced as a solution to the damages caused by the earthquake and tsunami.

http://www.chunichi.co.jp/s/article/2011051790154929.html provides a scenario for what happened at unit 2. On March 14th 10:50 AM pressure in the RPV rose to abnormal levels. Tepco performed venting twice, but because of some valve dysfunction, no pressure fall was confirmed. Then hydrogen leaked through welding cracks at the suppression chamber caused by the earthquake. The suppression chamber was damaged by the hydrogen explosion. An alternative view is that the explosion might have taken place inside the suppression chamber with oxygen flowing backwards during the venting.

 

[imandylite]

New video of Fukushima disaster site and reactors

Video taken 6 May 2011 - released 17 May 2011

https://www.youtube.com/watch?v=4k86qoCij_M

 

[jlduh]

Lots of new images from site published today, I think as part of their roadmap update:

http://www.tepco.co.jp/en/news/110311/index-e.html

Most of the images I don't find very interesting, but there is also a 13 minute video showing a variety of scenes on site. They really have sprayed that anti-scattering agent all over the place.

The roadmap update isn't available in English yet but a quick look at the Japanese version suggests that this is as much about a desire to show all the 'progress' they have made, as it is a serious update of technical measures required.

Of interest, here is a picture of what they define as being the diesel generator building 6B for reactor N°6:

http://www.tepco.co.jp/en/news/110311/images/110517_22.jpg

it seems that these generators are finally at the top floor of this platform (see the exhaust pipes) on this newer generation of reactors... (or is it just the cooling system at the top?)

Why if the max tsunami was 5,7m by their calculations? Is it the admittance that they were wrong with earlier designs, even they didn't modify it (putting those generator on a platform was not an impossible modification for reactor 1 to 4 IMO).

EDIT: this platform is cooling equipment for the EDG building, it's much clearer in the video, i extracted this picture which shows it (the blue wall at the top was from the reactor behind). So EDG are not on a platform as i imagined above...

http://www.netimago.com/image_200947.html

 

[mamoru]

Of interest, here is a picture of what they define as being the diesel generator building 6B for reactor N°6:

http://www.tepco.co.jp/en/news/110311/images/110517_22.jpg

it seems that these generators are finally at the top floor of this platform (see the exhaust pipes) on this newer generation of reactors... (or is it just the cooling system at the top?)

Why if the max tsunami was 5,7m by their calculations? Is it the admittance that they were wrong with earlier designs, even they didn't modify it (putting those generator on a platform was not an impossible modification for reactor 1 to 4 IMO).

I think it is only the exhaust system and the cooling, IIRC they are in the basement in each turbine building. Keep in mind that the power of diesel generators in place range from rougly 3 up to 5 MW (3000~5000 kW each), the engine should be a V18. On the tepco website (japanese side only) it is possible to find some images and you can see their dimensions.

For the tsunami, it is true that the wall was made according to 5.7m estimate, but many are forgetting that the buildings has been placed at OP +10000 (u1 to u4) and OP +13000 (u5 and u6), for the latter it is thought this saved one of the D/G.

 

[elektrownik]

No, this image is common SFP cooling system
btw they injecting 18m3/h to unit 3 now...

 

[jlduh]

I think it is only the exhaust system and the cooling, IIRC they are in the basement in each turbine building. Keep in mind that the power of diesel generators in place range from rougly 3 up to 5 MW (3000~5000 kW each), the engine should be a V18. On the tepco website (japanese side only) it is possible to find some images and you can see their dimensions.

For the tsunami, it is true that the wall was made according to 5.7m estimate, but many are forgetting that the buildings has been placed at OP +10000 (u1 to u4) and OP +13000 (u5 and u6), for the latter it is thought this saved one of the D/G.

Yep, I edited my post above after viewing the video...

On the other hand, if they placed N°5 and 6 at +13m, one could find this strange if +10m was already considered safe with some margin for a 5,7m tsunami... Wasn't it the admittance that they already had raised some doubts?

In the movie from Adam Curtis that i posted yesterday

http://www.bbc.co.uk/blogs/adamcurtis/2011/03/a_is_for_atom.html

(which talks about US, GB and USSR, not Japan),

it is shown that this period when these first reactors were built was a period of kind of exaltation of nuclear power, everybody had to go quickly to stay in the race and the guys interviewed in the video (who participated to this era as scientists and experts) admit that there was very little place for safety concerns at first... Then the doubts were raised about containment problems and so on. So this could apply to others risks. Still, Tepco was stating at the end of 2010 that 5,7m run up was the worst case scenario, so +10m was ok. +13m for 5 and 6 was even luxury with no real calculation basis in this case, don't you think? Waste of money even!

Well, to a certain extent, we have to consider that several factors are taking place in the designs standpoint, talking about elevation heights.

1) build on some solid "bedrock" or "mudstone" (for earthquake robustness) implies removing al lot of unstable surface sediments (25m for 1 to 4 it seems). This is a lot of work. From this standpoint, the less you remove, the lowest the construction cost is.

2) but if the plant is higher regarding to water intake (sea level), this means that the electrical consumption of pumps to send these continuous huge volumes of water to cool down the reactor (in fact to condense the steam in the condensers) will increase, which is not good for production costs!

So the altitude of the buildings is a trade off between safety and cost from this standpoint i think.

 

[Samy24]

Everything else fine in #3 temperatures except those two RPV readings:

The other one is 258,6 degrees, 16th of May, 5:00 (second highest).
The highest has been 269,6 degrees, 15th of May, 14:00.

The other one is 267 degrees, 16th of May, 5:00.
The previous high was 262,7 degrees, 16th of May, 2:00.

http://www.tepco.co.jp/nu/fukushima-np/f1/images/032_1F3_05160600.pdf

TEPCO may see this a little different. Again the water flow from the two pathes was increased. Now at 18 m³/h.

 

[imandylite]

Edited with links

New video of Fukushima disaster site and reactors

Video taken 6 May 2011 - released 17 May 2011

https://www.youtube.com/watch?v=4k86qoCij_M

http://www.youtube.com/watch?v=4k86qoCij_M"

http://www.tepco.co.jp/en/news/110311/"

The TEPCO pictures on the source page are taken from the video. They give title and partial explanation to the scenes on the video.

 

[tsutsuji]

It is also news to me from this document, that the RPV during the period of the 'black smoke event' on March 21st briefly peaked out at >12MPa, before it dropped back abruptly and went down to to atmospheric. My,my.

Are you talking about the graph page 41/66 of http://www.tepco.co.jp/nu/fukushima-np/plant-data/f1_8_Parameter_graph.pdf ?

3 data are between 8 and 12 MPa, but it is difficult for me to read the date more precisely than sometime between March 18th and March 23rd.

I am interested in any interpretation of what happened at any unit late on March 20th or early in the morning on March 21st, because I am curious about the radioactivity peak recorded in Mito at 6 AM on the morning of March 21st, as in most cities in Eastern Japan on that date, which I believe is also connected to the "don't give tap water to babies" crisis in Tokyo during the following days (http://www.guardian.co.uk/world/2011/mar/23/tokyo-water-unsafe-infants ).

My previous posts on that topic :
https://www.physicsforums.com/showthread.php?p=3258585#post3258585 (with Mito 6 AM March 21st peak attachment)
https://www.physicsforums.com/showthread.php?p=3258806#post3258806 (about the gap in Tepco data)

For what it's worth, I posted about Kenichi Ohmae's somewhat isolated view of black smoke being something serious at https://www.physicsforums.com/showthread.php?p=3229089&highlight=Ohmae#post3229089

 

[jlduh]

No, this image is common SFP cooling system
btw they injecting 18m3/h to unit 3 now...

Nope, this is not, even if it looks like!

Look at the latest video from Tepco:

http://www.youtube.com/watch?v=4k86qoCij_M&feature=player_embedded

T=5'44 the building behind even if it is undamaged is NOT N°2 reactor. Plus in the video this area is clearly a different area from N°1 to 4 reactor, this is N°5 en N°6.

 

[jlduh]

Find attached photos from two angles of a cylindrical oject lying leaned to the roof wall of turbine building 3. Seen from the THawk angle, one can well interpret the object as being connected to the piping there, i.e part of the original installation, albeit somewhat damaged. However, seen from the west in a zoom from one of the herostratic high resolution photos, it can be seen that it is not mounted, but has crashed on top of the original pipe. It has not been possible for me to find any satellite photo from before the unit3 explosion showing this object. So, I am led to believe that this object could be one of the ballistic objects. I have no idea what it could be, and where it sat in the building before the explosion. No high hopes that anybody can identify it, there are few clues except shape and a peculiar coat it appears to have been lined with.

You are right sir, this picture before/after confirms this: this kind of elongated tank was not there at first:

http://www.netimago.com/image_200952.html