Japan Earthquake: nuclear plants

83729780

return of the giant cloth

Gov't eyes use of huge sheet to contain radioactive substances
TOKYO, April 4, Kyodo

The government has asked Tokyo Electric Power Co., operator of the crippled Fukushima Daiichi nuclear plant, to study the possibility of containing radioactive substances from four damaged reactors by wrapping their entire containment buildings with a huge amount of sheeting, government sources said Sunday.

The proposal calls for building framed structures around the 45-meter-high containment buildings and then wrapping them with the sheeting, the sources said.

If all of the four buildings were wrapped in this manner, it would cost about 80 billion yen and take up to two months, the sources said.

But atomic energy experts are skeptical about the feasibility of the plan, proposed by a general construction firm, saying the step would have only limited effects in blocking the release of radioactive substances into the environment.

Osaka University professor emeritus Keiji Miyazaki said that there is the risk that such sheeting would be torn apart by heat emanating from nuclear reactors. ''What must be done speedily is rather the restoration of the reactors' cooling functions,'' said the professor of atomic energy engineering.

Ritsumeikan University professor emeritus Ikuro Anzai said if sheeting-based containment were technically possible, it would help block the release of radioactive substances into the atmosphere and the ground.

But the professor, who specializes in ways to protect humans from radiation exposure, added that there is the risk that radiation levels would go up inside the sheeting, thus hampering various restoration work, including the work to spray water onto the reactors.

A source close to the government criticized its latest move, saying, ''Politicians and the TEPCO management adopted the proposal from the major construction company which does not have deep knowledge about nuclear power plants.''

''This step is essentially lip service to give the public a sense of ease by hiding the image of the decrepit nuclear plant,'' the source said.

http://english.kyodonews.jp/news/2011/04/82921.html

TCups

NEW ANALYSIS OF THERMAL (IR) IMAGES, BLDG 3

Again, before annotation:

http://i306.photobucket.com/albums/n.../Picture44.png

and after annotation:

http://i306.photobucket.com/albums/n.../Picture45.png

Seems to confirm that the FHM is not over the SFP3; however, the rod-like structures seen at the alleged crash site of the ballistic FHM are not "hot" on this image.

Thanks again to tsustuji @post # 2680 for the IR images provided
http://www.physicsforums.com/showpos...postcount=2680

Jorge Stolfi

Re the damage of #4 and the piece of debris stuck into the roof:

Its part of the roof of Unit 4 that fell back down after explosion .

Thanks, it makes sense. Presumably the roof was a concrete or tarmac sheet laid on top of the metal framework, that was lifted off by the explosion without damaging the latter.

But now that the "shot by reactor #3" theory is busted, I am left wondering at puzzling features of the damage on #4:

The concrete walls of the upper floor, on the West and East sides, seem to have been pushed INWARDS against the concrete columns.
The same concrete shell on the North side (facing #3) was peeled off the concrete columns but kept hanging from the top.
The top edge of the North wall was bent INWARDS, whike the first horizontal concrete beam just below it was bent outwards.
While that beam was damaged, the much weaker outre shell remained mostly in place.

Could go on, buy you get the idea.

Perhaps there was an explosion BELOW the topmost floor, and that created overpressure on the OUTSIDE of the walls of the top floor, pushing them in?

downwinder

My only agenda is to get to the truth of the matter at hand.

If there were criticality events, the inventory associated with MW-s/MTU are quite small relative to the existing inventory.

I have stared at levels of 100 msv/hr many times and am no stranger to the events that are happening. As I have been following the events for the last couple of weeks on this site and elsewhere, I have concluded that the radiation levels are so intense that no one is able to gather the facts, evidence or pictures to conclude just exactly what has occurred, what the current conditions are and how they are going to get this under control. I suspect that the debris is such that no robots will be able to penetrate the debris field to obtain required information to access the situation. This may go on until decay heat and radiation levels subside or they just decide to pour concrete over the whole thing and dedicate it as a shrine to nuclear power. If they do that it will be interesting is to see how the ground water issue is resolved.

If you are looking for MW-s/MTU as an indication of a criticality in the reactors or fuel pools you never did the sub critical experiments in your MS engineering curriculum. It just takes a pulsed fission event to deplete the moderator or geometry to shut the event down only to reoccur when the geometry is again favorable. I would not find comfort in the fact that the power level is small relative to the reactor operating levels.

I_P

Quote by razzz

For reference, Wikipedia has a decent time lines and overall information combined together.

Fukushima I nuclear accidents

Wiki summarizes the public statements and conjectures from official sources, however the timeline is incomplete and all statements about the condition of units 1-4 are inferential. Measurements of radiation levels are spotty and incomplete as TEPCO's monitoring system went offline after the earthquake. Some data was intermittently collected by workers driving around in a car, however the data collected is insufficient to characterize the releases and changes in background levels.

There has been no entry into the damaged units, no photos released of building interiors (except a few inadequate shots of unit 4), it is uncertain what monitoring systems are delivering reliable data - most systems are offline due to damage. Radiation measurements taken by workers have been subject to revision after the fact....

Regarding unit 4 the Wiki timeline speaks of an explosion on March 15th that left 2 8m square holes in the walls (I recall the statements as 1 in a wall and one in the roof), however the current state of the structure shows massive damage - when and how did this occur?

Radiation levels spiked at the prefecture monitoring stations early on March 21st and are only now returning to where they were on the 19th. TEPCO said pressure was rising in unit 3 on the 20th and suggested they might need to vent it - but then the levels declined without intervention and now the containment is at atmospheric pressure.... what happened? No statements have been forthcoming other than some waffling about the state of containment.

What is the state of the fuel storage pools in units 1,3,and 4 given the explosive destruction we can see in the aerial photos?

Workers cannot access many areas of the site because of high radiation levels - what are the sources?

razzz

Quote by orndorf

So the I-134,Tellurium, lanthanum products and chlorine-38 readings are all wrong?

I dont believe it,but if true its very disturbing in its self.

What exactly is going on?

At least Gundersen is making a statement based on what information he has and standing by it,bias or no bias.

I know nothing about nukes. I read this complex lost power hence the ability to move water and these things happened after a 9.0+ quake and 45'+ ocean surge which ruined and/or disabled any functional mechanical equipment on site.

At this point in time, not counting the venting of radioactive materials, explosions, leakage, damaged and exposed nuclear material to the fresh air and corresponding fallout which is so bad that in some areas of ground zero you can't even stand there more than 10 minutes to work let alone people kicked out of their housing miles from the site.... most of us are waiting for what is left of the 3 nuclear cores and 4 spent fuel ponds to cool enough to start serious mitigation of the aforementioned conditions. Seems only unit 3 is not cooperating properly with cooling down completely at this time.

Some professionals can't agree on readings so there is some unknowns in play, at least in the publicly released information. Which is understandable because some conditions being encountered were never envisioned, times 4.

BTW, there is on going contamination and pollution as you read this due to the large amounts of water needed to cool the hot spots that shouldn't be reused and is lost as steam and in runoff to the sea anyway.

*robinson*

My questions about robotics is speaking to the point of radiation damage to electronics. If it was just alpha and beta robots could easily be sent in and around with cameras, to at least get a look at what is or isn't there.

Both gamma radiation and neutron radiation disrupt circuits, but as somebody noted, just seeing where the radiation knocks a small robot out would still be a source of information.

razzz

I_P says: Wiki summarizes the public statements and conjectures from official sources...

I said reference. It's certainly not a case study. Since anyone and their mother can submit to Wiki or bias can change the informational writeup at Wiki, yes, you do have to take the site with a grain of salt (it has always been a drawback with Wiki due to potential scrubbing of facts by entities with agendas)

Cites abound in the footnotes.

Wiki is fluid, I was checking the chart concerning fuel 'assemblies' on-site, left and came back to find 'new fuel assemblies' column added to the chart. As I read it, doesn't add to the totals just tells you how many of the newer (potent/longer life) fuel assemblies are present.

*AntonL*

Quote by TCups

Thanks again to tsustuji @post # 2680 for the IR images provided
http://www.physicsforums.com/showpos...postcount=2680

Yes, I am sure tsustuji san is interested in a bit more what Tepco and his government tell him.

There are more, I combined the history in three pdf files

when analysing, please be careful of reflected heat by the sun and on some images one can see the shadows of the buildings in the morning sun

To translate just select Japanese text and paste into translate.google.com

on more file for the 20th in the next post

*AntonL*

in continuation thermal image for the 20th march

shogun338

Is the fuel crane normally located in the top floor of the Unit ? In Unit 4 pics it is sitting on floor of second floor of blow out from top . Would this position be the bottom of spent fuel pool ?

*AntonL*

Quote by TCups

ADDENDUM:
Correction of initial error of interpretation on my part - the "ground activity is not from heat sources on the ground. There is a perspective error. The heat sources labeled "ground activity are from lower levels of the building. Also, remember, these images are in the IR spectrum, presumably, not the X-ray or gamma ray spectrum.

Look at attached image - you can see the shadow of the morning sun, so ground activity are sun reflecting of the side walls and other objects on the ground. this image from 30 march

shogun338

Quote by TCups

NEW THERMAL IMAGE ANALYSIS, UNIT 4

Thanks for the new images, tsutsuji @ post # 2680

http://www.physicsforums.com/showpos...postcount=2680

Here are new thermal images (at least to me) of Bldg. 4. I presume the "hot" area to the right of the SFP is the open core of the reactor with residual radioactivity, and I hope this is normal.

Without,

http://i306.photobucket.com/albums/n.../Picture41.png

and with my annotations.

http://i306.photobucket.com/albums/n.../Picture42.png

ADDENDUM:
Correction of initial error of interpretation on my part - the "ground activity is not from heat sources on the ground. There is a perspective error. The heat sources labeled "ground activity are from lower levels of the building. Also, remember, these images are in the IR spectrum, presumably, not the X-ray or gamma ray spectrum.

{open core of the reactor with residual radioactivity, and I hope this is normal.} I think the heat seen here is from fuel rods that where reported to have been blown out during explosion at Unit 4 . They reported that fuel rods where scattered in Unit 4.

shogun338

Quote by AntonL

Look at attached image - you can see the shadow of the morning sun, so ground activity are sun reflecting of the side walls and other objects on the ground. this image from 30 march

Ground heat will not show like that on a thermal camera . There is something there more than normal ground heat . They have reported that fuel rods in Unit 4 where scattered during explosion .

*AntonL*

Quote by shogun338

Ground heat will not show like that on a thermal camera . There is something there more than normal ground heat . They have reported that fuel rods in Unit 4 where scattered during explosion .

Browse through the the pdf files in post 2716 and you will see exactly areas that are illuminated by the sun and areas in shadows and on cloudy days these areas are absent.

However, I agree to you there are heat sources on the roof of unit 4 that do not tie in with the SFP

shogun338

Quote by AntonL

Look at attached image - you can see the shadow of the morning sun, so ground activity are sun reflecting of the side walls and other objects on the ground. this image from 30 march

Upper arrow is pointing to where a gray mass was in a pic I posted . Showing a lot of heat there .

*AntonL*

This image of 29th March shows clearly area illuminated by sun, the shaddow unit 4 casts

But the the roof of unit4 has heat outside the SPF

Similar Threads for: Japan Earthquake: nuclear plants
Thread	Forum	Replies
8.9 earthquake in Japan: tsunami warnings	Current Events	671
New Nuclear Plants	Nuclear Engineering	9
Gen IV Nuclear Plants	Nuclear Engineering	10
New Nuclear Plants	Nuclear Engineering	14
Astronomer Predicts Major Earthquake for Japan	General Discussion	65

shogun338	Is the fuel crane normally located in the top floor of the Unit ? In Unit 4 pics it is sitting on floor of second floor of blow out from top . Would this position be the bottom of spent fuel pool ? Attached Thumbnails

AntonL	This image of 29th March shows clearly area illuminated by sun, the shaddow unit 4 casts But the the roof of unit4 has heat outside the SPF Attached Thumbnails