Japan Earthquake: Nuclear Plants at Fukushima Daiichi

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The Fukushima Daiichi nuclear plant is facing significant challenges following the earthquake, with reports indicating that reactor pressure has reached dangerous levels, potentially 2.1 times capacity. TEPCO has lost control of pressure at a second unit, raising concerns about safety and management accountability. The reactor is currently off but continues to produce decay heat, necessitating cooling to prevent a meltdown. There are conflicting reports about an explosion, with indications that it may have originated from a buildup of hydrogen around the containment vessel. The situation remains serious, and TEPCO plans to flood the containment vessel with seawater as a cooling measure.
  • #2,851
TCups said:
I see the rails for the overhead crane as highlighted in red, and the large wench on the overhead crane as highlighted in yellow.

large wench ?

I suppose that's one way to get employees to work in high radiation zones!
 
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  • #2,852
AtomicWombat said:
large wench ?

I suppose that's one way to get employees to work in high radiation zones!

Sorry - I looked for an appropriate picture to illustrate, but I couldn't find one :blushing:
 
  • #2,853
jensjakob said:
Trench dimensions:
3x4x76 meters.
Source: http://www3.nhk.or.jp/daily/english/28_h37.html

The trench is only 4 m high. In its 16 m inspection shaft, the water is 14.9 m high :?
http://goo.gl/KXFTe

Doesn't that mean that the 4 m trench is already full :?
 
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  • #2,854
aruna said:
The trench is only 4 m high. In its 16 m inspection shaft, the water is 14.9 m high :?
http://goo.gl/KXFTe

Doesn't that mean that the 4 m trench is already full :?

At this rate of discharge (in the pics) it will take a while to get full.

[URL]http://www.asahi.com/photonews/gallery/fukushimagenpatsu2/images/0402_plant2.jpg[/URL]
[URL]http://www.asahi.com/photonews/gallery/fukushimagenpatsu2/images/0402_plant1.jpg[/URL]

They could stop dumping water on the reactor #2 core to cool it, because that is where the water originates from, but then the core would heat up and make more trouble, so we just live with a little pollution/contamination for awhile.
 
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  • #2,856
From:
http://www3.nhk.or.jp/daily/english/05_25.html"

"Tokyo Electric Power Company says it detected 300,000 bequerels of iodine-131 per 1 cubic centimeter, or 7.5 million times higher than the legal limit in samples taken around the water intake of the No. 2 reactor at 11:50 AM on Saturday.

It also found 200,000 bequerels or 5 million times higher than the limit in samples taken at 9AM on Monday.

Monday's sample also shows 1.1 million times higher than the national limit of cesium-137 whose half-life is 30 years."

They keep "moving the goal posts". It used to be the iodine-131 concentration was 5000 times higher than would normally be found in the reactor. And the level of cesium-137 is not even given - just referenced to the national limit.

I assume I-131 at 300 Mbq/m^3 is a lot.
 
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  • #2,857
TCups said:
http://i306.photobucket.com/albums/nn270/tcups/Screenshot2011-04-04annotated.png
http://i306.photobucket.com/albums/nn270/tcups/Screenshot2011-04-04at50940PM.png

I don't think its a transfer chute but rather a pool. As far the rest of the picture is concern I've been trying to read the picture for a few hours and.. I'm not sure of what I'm seeing.


the video is conveniently cut from 13:22 to 15:xx
 
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  • #2,858
OK, it seems that the questions "How are the RPV temperatures measured?" and "Are those things broken fuel rods?" are not going to get answered that soon.

How about this one, "Why is the word 'pressure' automatically linked in this forum, while 'temperature' is not?"?
 
  • #2,859
AtomicWombat said:
From:
http://www3.nhk.or.jp/daily/english/05_25.html"

"Tokyo Electric Power Company says it detected 300,000 bequerels of iodine-131 per 1 cubic centimeter, or 7.5 million times higher than the legal limit in samples taken around the water intake of the No. 2 reactor at 11:50 AM on Saturday.

It also found 200,000 bequerels or 5 million times higher than the limit in samples taken at 9AM on Monday.

Monday's sample also shows 1.1 million times higher than the national limit of cesium-137 whose half-life is 30 years."

They keep "moving the goal posts". It used to be the iodine-131 concentration was 5000 times higher than would normally be found in the reactor. And the level of cesium-137 is not even given - just referenced to the national limit.

I assume I-131 at 300 Mbq/m^3 is a lot.

And 300 Gbq/m^3 is even more...
 
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  • #2,860
|Fred said:
I don't think its a transfer chute but rather a pool. As far the rest of the picture is concern I've been trying to read the picture for a few hours and.. I'm not sure of what I'm seeing.


the video is conveniently cut from 13:22 to 15:xx

@Fred

Do you agree with the position of the crane? Do you think that thin line near the lateral margin of the crane is a short section of an arc? Do you think that jet of steam is under pressure? If those fit, then what other part of a pool comes that near the primary containment's plug other than the transfer chute?

There appears to be a label peeling off the side of the crane. Is that a clue that means anything to you?

PS: Fred - thanks for your feedback. I value your opinions.
 
  • #2,861
I hope that nuclear power plants all around the world are given safety upgrades to make sure than the Fukashima incident can not happen again.

Are nuclear power plants in earthquake-prone areas such as in California, vulnerable to having their cooling systems knocked out by earthquakes and tsunamis?
 
  • #2,862
http://en.wikipedia.org/wiki/Criticality_accident"

Accident types

Criticality accidents are divided into one of two categories:

* Process accidents, where controls placed to prevent any criticality are breached,

and

* Reactor accidents, where deliberately achieved criticality in a nuclear reactor becomes uncontrollable. Excursion types can be classified into four categories depicting the nature of the evolution over time:

and http://en.wikipedia.org/wiki/Chernobyl_disaster#Experiment_and_explosion"

...It was not possible to reconstruct the precise sequence of the processes that led to the destruction of the reactor and the power unit building, but a steam explosion, like the explosion of a steam boiler from excess vapor pressure, appears to have been the next event. There is a general understanding that it was steam from the wrecked channels entering the reactor's inner structure that caused the destruction of the reactor casing, tearing off and lifting the 2,000-ton upper plate, to which the entire reactor assembly is fastened. Apparently, this was the first explosion that many[who?] heard.[23]:366 This explosion ruptured further fuel channels, and as a result the remaining coolant flashed to steam and escaped the reactor core. The total water loss in combination with a high positive void coefficient further increased the reactor power.

A second, more powerful explosion occurred about two or three seconds after the first; evidence indicates that the second explosion resulted from a nuclear excursion.[24] The nuclear excursion dispersed the core and effectively terminated this phase[clarification needed] of the event...

http://www.youtube.com/watch?v=T_N-wNFSGyQ"

Listen to the link. Maybe: The first explosion (hydrogen ignites?) voids the atmosphere and causes water to flash to steam across the reactor and then sounds like it happens again, each with it's own explosion and the final sound you hear in the heavy crossbeam hitting the desk with a resounding metallic thud and deep ringing. [edit: disregard hearing the beam land, it's localized background noise the mike picked up, I think)

No go zone, massive release of contamination at this time, then the company later states they will probably never be able to approach Unit 3.
 
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  • #2,863
|Fred said:
I don't think its a transfer chute but rather a pool. As far the rest of the picture is concern I've been trying to read the picture for a few hours and.. I'm not sure of what I'm seeing.the video is conveniently cut from 13:22 to 15:xx
Your right . Its the smaller pool on the right side of reactor if your looking at it from turbine building . Move left reactor that is leaking steam around it then main spent fuel pool on far left . I have a over flight video on my computer and have lined up the remaining beams and found the place in the photo . Unit 4 has a smaller spent fuel pool on right side so my guess is the layout is the same for Unit 3 .
 
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  • #2,864
A – Unit 3 turbine building containing the main turbine, main generator, condenser, condensate pumps, and condensate booster pumps. Roof damage possibly caused by debris from the Unit 3 reactor building (B) explosion
B - Unit 3 reactor building with extensive damage caused by hydrogen explosion
C – Unit 2 offgas line that transports air pulled from the condenser inside the Unit 2 turbine building during normal operation to the offgas building for treatment to reduce radioactivity levels before discharge to the atmosphere
D – Unit 3 offgas line that transports air pulled from the condenser inside the Unit 2 turbine building during normal operation to the offgas building for treatment to reduce radioactivity levels before discharge to the atmosphere
E – Unit 3 reactor building (B) exhaust line to the stack showing extensive damage
F – Unit 3 truck bay used to deliver canisters of new fuel assemblies into the reactor building (B) and its refueling floor
G – Unit 3 access hatch connecting the truck bay elevation with the refueling floor elevation inside the Unit 3 reactor building (B)
 

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  • #3 layout.jpg
    #3 layout.jpg
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  • #2,865
razzz said:
http://en.wikipedia.org/wiki/Criticality_accident"



and http://en.wikipedia.org/wiki/Chernobyl_disaster#Experiment_and_explosion"



http://www.youtube.com/watch?v=T_N-wNFSGyQ"

Listen to the link. Maybe: The first explosion (hydrogen ignites?) voids the atmosphere and causes water to flash to steam across the reactor and then sounds like it happens again, each with it's own explosion and the final sound you hear in the heavy crossbeam hitting the desk with a resounding metallic thud and deep ringing. [edit: disregard hearing the beam land, it's localized background noise the mike picked up, I think)

No go zone, massive release of contamination at this time, then the company later states they will probably never be able to approach Unit 3.

As stated many times previously in this thread the chernobyl reactor design has nothing in common with the one at fukushima. You cannot draw parallels between the two.
 
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  • #2,866
Maxion said:
As stated many times previously in this thread the chernobyl reactor design has nothing in common with the one at fukushima. You cannot draw parallels between the two.

It's not the designs, it's the reactions. Why 3 explosions in that link for unit 3?
 
  • #2,867
Echoes
 
  • #2,868
"I assume I-131 at 300 Mbq/m^3 is a lot."
Giordano said:
And 300 Gbq/m^3 is even more...

What's a few orders of magnitude between friends...
 
  • #2,869
razzz said:
It's not the designs, it's the reactions. Why 3 explosions in that link for unit 3?
The sound in that video has been added in by someone . I have the video of Unit 3 exploding and there is no sound like that . Where did they get the sound that was added to the video ?
 
  • #2,870
M. Bachmeier said:
Do you mean temperature is higher than is being reported? Do you have some supporting reference, link etc.?

Thermocouples have a known failure mode when overheated. First the precision opens up and then an offset develops. It's call decalibration and the sensor will return what appears to be a correct value, when it isn't.

This is why the IAEA keeps saying "The validity of the RPV temperature measurement at the feed water nozzle is still under investigation."

The fact that the water feed nozzle is showing a higher temperature (253 °C in unit 1) is a good indication of a failure. The feed water nozzle has the highest flow of the coldest water in the reactor at this time. At these injection rates the reported temperature is not correct.
 
  • #2,871
Japan has asked Russia to send a floating radiation treatment plant, used to decommission nuclear submarines, which will solidify contaminated liquid waste from the Fukushima Daiichi plant, Russian media reported.

Interesting.

http://www.tecsec.org/pdf/projectpostru01_e.pdf
 
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  • #2,872
shogun338 said:
The sound in that video has been added in by someone . I have the video of Unit 3 exploding and there is no sound like that . Where did they get the sound that was added to the video ?

The camera is miles away and sound does not travel that fast .
 
  • #2,873
Here is a labeled version of my "hallucination". The http://www.spiegel.de/images/image-198534-galleryV9-orwt.jpg" , was posted by AntonL.

image-198534-galleryV9-orwt-e.jpg


1 - fuel rods from one assembly?
2 - wider water tube from center of assembly?
3 - bottom of assembly?
4 - racks from spent-fuel pool?
5 - sleeve of assembly?
6 - sleeve of assembly, burst open, oxidized on outer side?
7 - water in/out pipes from spen-fuel pool?

Item 7 seems to match a model of the SPF shown on NHK. Items 6 of course are more likely to be metal roof panels (but where from?)

OK, time to go to bed...
 
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  • #2,874
I'll get back to you later Tcup I need to think more, meanwhile
here is an other diagram of a BWR that looks a lot like fukushima exept that the storage pool and the utility pool are inversed

from the same site, filled with information
http://www.nucleartourist.com/frame/index.html
I've learned that piping and lots of thing in a NPR are color coded... so all the pink stuff we are seeing are coded for something..

BWR100.jpg
 
  • #2,875
thank to the above site I leaned that the BWR 4 by GE was used in the Vermont Yankee (BWR-4) Plant
Vermont_Yankee_Nuclear_Power_Plant.jpg


and looking into this plant I was able to get this picture witch I believe is an accurate representation of what reactor 3 at fukushima looks like (with the exeption of the color coding)
[URL]http://cache.boston.com/resize/bonzai-fba/Globe_Photo/2009/05/03/1241407279_5282/539w.jpg[/URL]

I know need to think and try to figure what we could be seeing .. on the previous screen grab
 
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  • #2,876
Jorge Stolfi said:
Here is a labeled version of my "hallucination". The http://www.spiegel.de/images/image-198534-galleryV9-orwt.jpg" , was posted by AntonL.

image-198534-galleryV9-orwt-e.jpg


1 - fuel rods from one assembly?
2 - wider water tube from center of assembly?
3 - bottom of assembly?
4 - racks from spent-fuel pool?
5 - sleeve of assembly?
6 - sleeve of assembly, burst open, oxidized on outer side?
7 - water in/out pipes from spen-fuel pool?

Item 7 seems to match a model of the SPF shown on NHK. Items 6 of course are more likely to be metal roof panels (but where from?)

OK, time to go to bed...
Short line on #4 is pointing to top edge of spent fuel pool . On the pump cam video you can see this is where they are pouring water into . See pic I posted of spent fuel pool . #2650
 
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  • #2,877
shogun338 said:
The sound in that video has been added in by someone . I have the video of Unit 3 exploding and there is no sound like that . Where did they get the sound that was added to the video ?
If I remember right, footage was taken from the next nearest nuclear plant in line of sight. The distance accounts for the delayed sound waves other than that local background noise. What type of sound were you expecting to hear?
 
  • #2,878
Jorge Stolfi said:
Here is a labeled version of my "hallucination". The http://www.spiegel.de/images/image-198534-galleryV9-orwt.jpg" , was posted by AntonL.
1 - fuel rods from one assembly?
2 - wider water tube from center of assembly?
3 - bottom of assembly?
4 - racks from spent-fuel pool?
5 - sleeve of assembly?
6 - sleeve of assembly, burst open, oxidized on outer side?
7 - water in/out pipes from spen-fuel pool?

And don't forget the corium melt in the middle of the mess.

I must admit that 1 & 3 look highly suggestive, especially given the location. But until there is more evidence it's all a big maybe. I keep seeing fuel rods all over the place.

As to whether they should have melted or should show up on IR. Once the spent fuel rods have a good air supply they will probably cool by convection and not melt. The IR images are from above not from the side, so this site would be at least partially obscured by what's left of the ceiling. Finally, they would be below the resolution of the IR image, so the IR will just average them with their surroundings.

But, we need more evidence and we will probably never know. Shame.
 
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  • #2,879
razzz said:
If I remember right, footage was taken from the next nearest nuclear plant in line of sight. The distance accounts for the delayed sound waves other than that local background noise. What type of sound were you expecting to hear?
The sound comes to soon . Even if the camera was only one mile away it would take the sound of the explosion around 5 seconds or more to reach camera . Camera is more than a few miles away .
 
  • #2,880
Jorge Stolfi said:
How about this one, "Why is the word 'pressure' automatically linked in this forum, while 'temperature' is not?"?

This one I can help you with :biggrin:

Physics Forums library has entry for "pressure" but has not entry for "temperature".

Note that you can switch off automatic library linking in your profile.
 

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