Japan Earthquake: nuclear plants

razzz

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 from a reconstruction of the Chernobyl disaster (also Wikipedia)...

...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...

Fukushima I Nuclear Power Plant Reactor 3 explosion on March 14, 2011

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.

shogun338

Quote by |Fred

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 .

shogun338

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)

Maxion

Quote by razzz

From Wikipedia...

and from a reconstruction of the Chernobyl disaster (also Wikipedia)...

Fukushima I Nuclear Power Plant Reactor 3 explosion on March 14, 2011

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.

razzz

Quote by Maxion

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?

Godzilla1985

Echoes

AtomicWombat

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

Quote by Giordano

And 300 Gbq/m^3 is even more...

What's a few orders of magnitude between friends...

shogun338

Quote by razzz

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 ?

Cire

Quote by M. Bachmeier

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.

Cire

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

shogun338

Quote by shogun338

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 .

Jorge Stolfi

Here is a labeled version of my "hallucination". The hi-res image of Unit #4, SE corner, 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?

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...

|Fred

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..

|Fred

thank to the above site I leaned that the BWR 4 by GE was used in the Vermont Yankee (BWR-4) Plant

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)

I know need to think and try to figure what we could be seeing .. on the previous screen grab

shogun338

Quote by Jorge Stolfi

Here is a labeled version of my "hallucination". The hi-res image of Unit #4, SE corner, 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?

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

razzz

Quote by shogun338

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?

AtomicWombat

Quote by Jorge Stolfi

Here is a labeled version of my "hallucination". The hi-res image of Unit #4, SE corner, 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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\|Fred	thank to the above site I leaned that the BWR 4 by GE was used in the Vermont Yankee (BWR-4) Plant 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) I know need to think and try to figure what we could be seeing .. on the previous screen grab

Godzilla1985	Echoes