Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[|Fred]

@curious11
Could it be tar ?

 

[DSamsom]

From IAEA's daily briefing:

"On 5th April, measurements were made at 7 locations at distances of 16 to 41 km, South and South West to the Fukushima nuclear power plant. The dose rates ranged from 0.3 to 31 microsievert per hour. At the same locations, results of beta-gamma contamination measurements ranged from 0.01 to 3.2 megabecquerel per square metre."

Interesting, since de data from MEXT in no way show these levels (31 microSievert/h, 3,2 MBq/m2) in south or south westerly direction. Measurements bij MEXT are taken on or close to the 20 km radius-line, so the difference might be explained by the difference between 16 km an 20 km, but that seems unlikely because the distance-dose ratio isn't that steep. Is MEXT selectively choosing its monitoring posts? Or is IAEA?

 

[Jorge Stolfi]

I have known a couple of photo recon interpreters who told me it is hard not to see things after looking at a photo too long or too hard. ... Next thing is likely to be somebody spotting bin Laden.

He he. But that is not reason not to try, is it? We are here mostly to learn, and for that asking stupid questions is essential...

 

[Imipak]

Excellent diagrams.
from this vid the vertical pressure wave does follow the first blast.

The "vertical pressure wave" is just the shock wave making itself visible by condensing water vapour in the air, *not* the blast wave itself. Moon, finger. A "vertically moving" compression wave does not necessarily mean there's no lateral blast wave, or that the vertical component was more powerful than the horizontal.

 

[M. Bachmeier]

Usually, those that I have worked with were U shaped pipes (Circular or U, they allow for expansion and contraction with temperature change. In the video it looked like the explosion came out of the combustion area. Those curved pipes are subject to external (fireside) acidic corrosion and are usually replaced in boilers that have a lot of use. When you get a rupture in a steam boiler operation, it is usually one of the tubes.

Yes and another point I should bring up is some fuels (bunker oil) can interact with (small) water leaks (water boilers) to make highly corrosive acid, which could lead to tube failure and seal failure.

 

[TCups]

Hi
Actually it was one of the first thing that was discussed on the thread when, the hole in the turbine building : could it be the concrete slag of the reactor.. at the time we had really low resolution picture.
Since then we got ok picture and you are right we can pretty much think that all those marks (dont let the perspective deceive you) came from the "windows" of last 2 floors( not sure witch floor) .. windows made of concrete panel.. when the building blowup they were eject in strait horizontal line + parabolic @ gravity

I made an other picture on this https://www.physicsforums.com/showpost.php?p=3223071&postcount=2347
if you look at the original HD picture that I used you'll get a better idea

PS: any how nice observation skodises2, keep them coming !

Uh . . . beg to differ with your flight path analysis.

First, go back and look at the elevation and consider the downward parabolic flight those heavy panels took.

Next, identify where 2 of 4 smacked the nearside back wall of the turbine building, bounced up, then crashed through the top of the building.

Next, identify where 3 more missed the back wall completely, skidded on the more distal aspect of the roof, and crashed through the front facade of the turbine building.

The one central panels were, I suppose somehow protected by the crane and didn't make it as far.

http://i306.photobucket.com/albums/nn270/tcups/Screenshot2011-04-05at44958PM.png

Just for fun, you can check out the two panels that hit the building to the west of Unit 3 as well, and the debris fields those left.

Remember to take into account the differential heights of the buildings when those big old slabs were lobbed outward.

Then tell us if you still think your initial assessment correct.

Addendum:

Sorry, I was speaking from memory. Actually 5 panels impacted the turbine building that I can identify.

http://i306.photobucket.com/albums/nn270/tcups/Screenshot2011-04-05at50011PM.png

 

[Astronuc]

If there were fuel debris, then I would expect to see channels and tie plates, and probably not fuel rods.

The channels are about 5.3 inches (134 mm) across and about 160 inches (~4 m) long.

An 8x8 fuel rod has an outer cladding diameter of 0.484 inch (12.3 mm) and the large central water rod has an outer diameter of about 1.3 inches (33 mm). Older 8x8-2 assemblies had smaller water rods.

 

[TCups]

Were starting with superheated water (like a glass of pure water heated in a microwave). If a (relatively) small leak (re: failure at seal of cap) blew out sideways through the transfer gate, there would be a sudden rapid expansion of volume in the remaining liquid. The pressure would increase so rapidly that any other weak point, including an overstressed torus could give way.

99% steam?

@Bachmeier

Thank you sir. I had forgotten that factor. The water in the pool, before the explosion would be absolutely as pure as possible. Look how still and clear the pools are in all the photos, too. The SFP water certainly could superheat then explode. Ever heat distilled, deionized water in a clean Erlenmeyer flask that you forgot to put a boiling chip in, then dropped one in after it got hot? Don't try it. You will get a first hand demonstration of what might have happened.

 

[M. Bachmeier]

@Bachmeier

Thank you sir. I had forgotten that factor. The water in the pool, before the explosion would be absolutely as pure as possible. Look how still and clear the pools are in all the photos, too. The SFP water certainly could superheat then explode. Ever heat distilled, deionized water in a clean Erlenmeyer flask that you forgot to put a boiling chip in, then dropped one in after it got hot? Don't try it. You will get a first hand demonstration of what might have happened.

Just wonder what would happen if I did that experiment again and dropped a salt tablet into the water to trigger the boiling. Funny reminds me of hot ice. By the way anybody who's done this experiment will tell you the force (rapid expansion) from 8oz. / 250ml of superheated water is unreal and dangerous.

P. S. Just found this, wonder if it has any bearing on the discussion:

http://en.wikipedia.org/wiki/Steam_explosion

 

[|Fred]

Uh . . . beg to differ with your flight path analysis.

wasn't analysis rather a quick and dirty drawing showing that they were more than the 2 panels suggested, and that they flue it rather strait line + gravity. ;)
I'll take your word for the proper flightpath.

ps looking at the video of the u3 explosion , doest anyone feel that there was more than one object of importance falling back ? 2 at least to the left of the picture and possibly one to the right.
Also doing frame by frame I have the optical illusion than just before the orange flash the roof dropped slightly as if it was compressed, does it make any sens explosion wise?
(Any cash course you would recommended to learns the basics of explosions ?)

 

[TCups]

wasn't analysis rather a quick and dirty drawing showing that they were more than the 2 panels suggested, and that they flue it rather strait line + gravity. ;)
I'll take your word for the proper flightpath.

ps looking at the video of the u3 explosion , doest anyone feel that there was more than one object of importance falling back ? 2 at least to the left of the picture and possibly one to the right.
Also doing frame by frame I have the optical illusion than just before the orange flash the roof dropped slightly as if it was compressed, does it make any sens explosion wise?
(Any cash course you would recommended to learns the basics of explosions ?)

Not me -- I am too old to enlist in the military.

I was wondering if there might be two major pieces of the FHM that separated. And we never saw that wench again after the explosion.

 

[|Fred]

If a (relatively) small leak (of hot steam) blew out , there would be a sudden rapid expansion of volume in the remaining liquid

Could you please point at the phenomenon so I could look it up.

 

[razzz]

I can't confirm the sound track to Unit 3 explosion. Count the seconds (2) after the flash to sound and divide by 5, you get less than a mile away or less then a km. Camera is reported to be 30km away.

Best sound for Unit 1 explosion I could find...

"watch?v=h6MaXQwHBqs"[/URL]

I go with M. Bachmeier's scenario so far. Unit 3 looks and acts like a launch pad with ignition, vertical lift and side exhaust. I just wonder what the fuel source was because a large amount of steam (superheated) would have to be under pressure to release like that. Hydrogen would have to be under pressure to lift the working platform and everything on it towards the sky.

Grey slags look like melted lead from batteries in Unit 4.

For a company that spends most of its time obfuscating or saying 'we don't know' there sure is a lot of contamination.

Tell the local natives that irradiation is good for them and will probably prevent the next cold/flu season. I don't who the Russians are trying to fool, they will just condense the wreckage then kick it over the side into the Pacific. Sure you don't want to use a controlled nuke blast and send everything around the globe in the upper atmosphere and into the Pacific, now, instead of this slow bleed? If units 5&6 fail, lookout.

I'm a product of public education so you can discount all I say.

From [PLAIN]http://en.wikipedia.org/wiki/Fukushima_I_nuclear_accidents"

At 11:15 JST on 14 March, the envisaged explosion of the building surrounding reactor 3 of Fukushima 1 occurred, due to the ignition of built up hydrogen gas.[249][250] The Nuclear and Industrial Safety Agency of Japan reported, as with unit 1, the top section of the reactor building was blown apart, but the inner containment vessel was not breached. The explosion was larger than that in unit 1 and felt 40 kilometers away. Pressure readings within the reactor remained steady at around 380 kPa at 11:13 and 360 kPa at 11:55 compared to nominal levels of 400 kPa and a maximum recorded of 840 kPa. Water injection continued. Dose rates of 0.05 mSv/h were recorded in the service hall and of 0.02 mSv/h at the plant entrance.[251] It was reported that day that eleven people were injured in the blast.[252] Six soldiers from the Japanese Central Nuclear Biological Chemical Weapon Defence Unit are reported to have been killed in the explosion.[253]

 

[M. Bachmeier]

Could you please point at the phenomenon so I could look it up.

Sorry, this link added after (because i found it after) might help.

http://en.wikipedia.org/wiki/Steam_explosion

 

[razzz]

Could you please point at the phenomenon so I could look it up.

There was a report where the cap for this particular design fails and vents sideways at a certain pressure and found to be true in real time testing.

Until 4 vessel underwent hardening via reheating and slumped according to the man in charge of the reheating, he falsified the procedure by altering the computer program readouts, with the company's blessing and got a bonus for saving the company money by avoiding trashing the vessel. Employee recently came clean on the events, he was ignored.

 

[TCups]

Sorry, this link added after (because i found it after) might help.

http://en.wikipedia.org/wiki/Steam_explosion

So the superheated water in the SFP3 littorally exploded!

 

[ian_scotland]

This is my first post after following this thread for a few weeks now.
Many thanks to all who have provided such a fascinating insight for me. I am not an academic, but an architect - so please forgive me if I'm not on par with referencing quotes or material or have posted this reply incorrectly. It is also late here and I've had a very hard day looking after my kids!

Uh . . . beg to differ with your flight path analysis.

Next, identify where 2 of 4 smacked the nearside back wall of the turbine building, bounced up, then crashed through the top of the building.

Having watched the video of reactor 3 explosion, it is evident that a lot of material blasted upwards came down in the vicinity of reactor 3. We already have the hypothesis that the FMH went ballistic and arced back to the north end of unit 3. May I suggest that other heavy "stuff" is visibly returning too and it is this that caused the perforations to the roof of turbine buildings 3 and 4.

The parapet wall (the up-stand around the edge of the roof) is invariably of very lightweight construction as it is primarily just to catch rainwater and provide a visual edge to the roof. It is unlikely to have the strength to "bounce" [STRIKE]heavy[/STRIKE] concrete panels upwards.

EDIT upon further thought those reinforced concrete panels are going to spall significantly, and most likely be little more than fist sized bullets. Maybe enough material hanging together with some reinforcement bar to remove parts of the parapet wall but highly unlikely to penetrate the roofs turbine buildings. Such "shrapnel" evidence is visible beyond the turbine buildings too. Example given below (from MECHANICS OF QUASI-BRITTLE MATERIALS, Gianluca Cusatis, Ph.D)

source http://www.cusatis.us/?cat=6

http://www.cusatis.us/wp-content/uploads/2010/01/blast.png

 

[javadave]

what do you experts think of the latest NEI blog re: recriticality of the reactors?

http://neinuclearnotes.blogspot.com/2011/04/recritical-thinking.html

 

[PietKuip]

what do you experts think of the latest NEI blog re: recriticality of the reactors?

http://neinuclearnotes.blogspot.com/2011/04/recritical-thinking.html

That blog entry is correct. See also http://nucleardata.nuclear.lu.se/nucleardata/toi/nuclide.asp?iZA=520429 for data on Te-129m

The incredible thing is that Tepco do not understand their own measurements. See also http://www.nytimes.com/2011/04/06/world/asia/06tepco.html

Such a company should never have been allowed to operate a nuclear reactor.

 

[Emreth]

I seriously doubt that the FHM can go ballistic like that. It's a slim and heavy structure that can not provide enough resistance to the expanding gases which would would just flow around it. It's like putting something inside a cannon which does not fit snugly, not enough momentum will be transferred to the object. I think with the first explosion, which is somewhat directed sideways, the FHM might be hurled against the north destroying that side, depending on the blast location, i assume would be close to SFP. In the top views of reactor 3, i also saw some green areas in the SFP, maybe those are pieces of the FHM as well. The first explosion looks kind of dirty compared to a hydrogen explosion, the fireball is very red/yellow, maybe the mixture was poor in oxygen. The implosion from that seems to trigger the secondary explosion. It might be a steam blast when a low gas density/vacuum formed in there. The explosion seems the pulverize a lot of the concrete stuff, hence the dirty dusty look. I think parts of the ceiling trusses are what are coming down afterward.

 

[Astronuc]

That blog entry is correct. See also http://nucleardata.nuclear.lu.se/nucleardata/toi/nuclide.asp?iZA=520429 for data on Te-129m

The incredible thing is that Tepco do not understand their own measurements. See also http://www.nytimes.com/2011/04/06/world/asia/06tepco.html

Such a company should never have been allowed to operate a nuclear reactor.

So they messed up with Co-56 vs I-134, Cl-38, and Te-129/129m. And TEPCO is not sure about the Te-129

That certainly does raise concern.


I've seen site and utility management replaced over much lesser problems.

 

[tyroman]

@Tcups;

From your post #2936:
https://www.physicsforums.com/showpost.php?p=3230713&postcount=2936
"The reactor vessel is now mostly dry, really, really (red?) hot, and making hydrogen and oxygen."
and
"Gas in the primary containment ignites"

How does hot fuel make Oxygen? And where does the Oxygen needed to ignite Hydrogen in primary containment come from?

Please look again at my Mar25-11, 02:31 PM post #1227 on page 77 of this thread:
https://www.physicsforums.com/showpost.php?p=3209718&postcount=1227

For your theory to be justified, we need to resolve the question of how Oxygen becomes available within primary contaiment in sufficient volume to satisfy Hydrogen's UEL (considering the presence of steam). This issue has STILL hot been addressed.

Tyroman

PS: In that post, where I say;

"When Hydrogen burns (explodes), there is one molecule of Oxygen for each molecule of Hydrogen;"

I obviously meant -
"When Hydrogen burns (explodes), there is one molecule of Oxygen for two molecules of Hydrogen;"

BTW, when I was in Armor, we referred to an armadillo as "A rat with a tanker's MOS."

.

 

[TedNugget]

Ian:

I've got over twice as many posts as you. Ha

"Having watched the video of reactor 3 explosion, it is evident that a lot of material blasted upwards came down in the vicinity of reactor 3. We already have the hypothesis that the FMH went ballistic and arced back to the north end of unit 3. May I suggest that other heavy "stuff" is visibly returning too and it is this that caused the perforations to the roof of turbine buildings 3 and 4."

I agree. That heavy roof came down somewhere and it might have been on the turbine roof.
In some of the photos there appears to be a directionality of debris from the east side of the reactor building. Look that over and see where the smaller puncture hole to the NE looks to be offset from that debris flow.
Looking over the superstructure of Reactor 3 there was a fair bit of steel that left the building. Wonder where that came down?


Maybe someone with double my posts will respond.

 

[tyroman]

As to panel trajectories from Unit 3...

Sketches I made some time ago but didn't post are attached. These were intended as a reply to a much earlier question about the origin of an almost intact panel leaning against the building just East of the turbine building.

The specific panel in question probably was a Southmost-East facing panel from either the top or second row of panels of Unit 3.

BTW - perspective does make it difficult to judge the source...

.

 

[Bob S]

This just in from TEPCO (May be a duplication)

At 5:38 am on April 6th, we observed the stoppage of the water spilling
from the crack on the concrete lateral of the pit. Details of the
situation will be announced after checking the blockage of the water
flows.

We will continue the countermeasure in order to prevent further outflow
of high level radioactive materials to the ocean.

From http://www.tepco.co.jp/en/press/corp-com/release/

Bob S

 

[Homer Simpson]

For your theory to be justified, we need to resolve the question of how Oxygen becomes available within primary contaiment in sufficient volume to satisfy Hydrogen's UEL (considering the presence of steam). This issue has STILL hot been addressed.

There is no shortage of oxygen in the containment is there, it is air after all? Steam is factored when determining the hydrogen deflagration/detonation ranges of H2 in air. The presense of steam limits the ranges for explosion, but does not eliminate it.

 

[turbo]

So they messed up with Co-56 vs I-134, Cl-38, and Te-129/129m. And TEPCO is not sure about the Te-129

That certainly does raise concern.

I've seen site and utility management replaced over much lesser problems.

I hope it's a matter of translation problems and/or exhaustion of the tech workers, and not a matter of incompetence. Finding high levels of very short-lived isotopes (indicative of on-going fission) should have set off some mental alarms in the engineering/technical staff, prompting a lot of double-checking.

With talk of entombment in some circles, this raises a concern in my mind. The process of setting/curing concrete is exothermic. Could entombment result in insufficient cooling of fuels, leading to unanticipated problems? Coming at this from a civil/mechanical mind-set with NO experience in nuclear leaves a lot of questions.

 

[skodises2]

As to panel trajectories from Unit 3...

Sketches I made some time ago but didn't post are attached. These were intended as a reply to a much earlier question about the origin of an almost intact panel leaning against the building just East of the turbine building.

The specific panel in question probably was a Southmost-East facing panel from either the top or second row of panels of Unit 3.

I just took a look at the satellite photos from post-tsunami, but pre-explosion. I'm not positive, but I think that that horizontal structure you are indicating was actually already there pre-explosion: I don't think that that is a panel from the reactor building. Check the attached image and see what you think. It looks to me like a drive-under weather shelter, perhaps, like a carport.

I'm looking to see if I can find a better image- but I think that that structure predates the blast, rather than somehow having survived it intact and come to rest there. What do you think?

On edit- added two more that also look tantalizingly as if that structure was already there. The last image, fuku3_6a.jpg, is a photo from prior to the earthquake and tsunami.

Having said that, I can see where my initial idea about trajectories posted above was flawed. Thanks, all, for the education...

Original images: http://www.digitalglobe.com/digitalglobe2/downloads/featured_images/japan_earthquaketsu_fukushima_daiichi_march12_2011_dg.jpg
https://lh6.googleusercontent.com/-...00/japan_fukushima_daiichi_after_03_14_11.jpg
https://lh6.googleusercontent.com/-...00/japan_fukushima_daiichi_after_03_14_11.jpg

 

[tyroman]

@Homer Simpson

The issue to be resolved is two-fold... What is "Hydrogen's UEL (considering the presence of steam)."? And what is the source of the Oxygen (as I remember, the primary containment is filled with N2)?

What we do not know is the relative (by volume) composition of the three gases (H2, O2 and H2O) in containment and whether that composition would support combustion.

Within your experience, how would we go about answering these issues?

.

 

[TCups]

I seriously doubt that the FHM can go ballistic like that. It's a slim and heavy structure that can not provide enough resistance to the expanding gases which would would just flow around it. It's like putting something inside a cannon which does not fit snugly, not enough momentum will be transferred to the object. I think with the first explosion, which is somewhat directed sideways, the FHM might be hurled against the north destroying that side, depending on the blast location, i assume would be close to SFP. In the top views of reactor 3, i also saw some green areas in the SFP, maybe those are pieces of the FHM as well. The first explosion looks kind of dirty compared to a hydrogen explosion, the fireball is very red/yellow, maybe the mixture was poor in oxygen. The implosion from that seems to trigger the secondary explosion. It might be a steam blast when a low gas density/vacuum formed in there. The explosion seems the pulverize a lot of the concrete stuff, hence the dirty dusty look. I think parts of the ceiling trusses are what are coming down afterward.

You are probably correct. After all, how could a blast like the large column rising in the center of this photo lift and toss aside something as massive as a fuel handling machine. BTW, what is the approximate size of that, uh, kind of green looking . . . "what are you-call-it" or "thingamabob" falling there to the right of the massive vertical column of the blast at unit 3?

http://i306.photobucket.com/albums/nn270/tcups/Falling-FHM.jpg

BTW, did you catch the earlier extensive photo analysis back there a few days ago where several of us spent hours lining up the towers, the sun, and the buildings to figure out where that long, green looking thing came down? That may have been wrong too, I suppose.

 

[Homer Simpson]

@tyroman,

Hi, my experience is nothing really, only that candu's have h2 igniters for this reason, mind you there is certainly no N2 cover gas for containment in candu's ...check the below link incase you haven't come across a chart such as this one... page 7/42

http://canteach.candu.org/library/20044507.pdf

 

[TCups]

Within your experience, how would we go about answering these issues?

Hell, maybe I am wrong about the blast coming out of the primary containment. Now that M. Bachmeier has pointed us toward the consideration of littoral explosions (you know, like the one that blew a few cubic miles of Earth out of the side of Mt. St. Helens a few years back?)

http://www.worldtravelattractions.com/wp-content/uploads/2010/10/Mount-St.-Helens-eruption-1980-300x200.jpg

Would you describe the eruption from the SFP at Unit 3 as "Vesuvial"? Most likely not.

http://toxipedia.org/download/thumbnails/442/Vesuvius1822scrope.jpg

http://i306.photobucket.com/albums/nn270/tcups/Falling-FHM.jpg

And after all, there was no dirt and rocks in Building 3, well -- only other stuff (concrete, asbestos, odds and ends and such). And hot fuel rods and hot magma don't have anything much in common, except, what? . . . Heat?

Sorry for being so sarcastic -- just tired this evening. But somehow my gut tells me that there was hydrogen below, hydrogen above, superheated water in the SFP and a blow-out of the fuel transfer gate touched the whole shebang off like a John Lee Hooker blues tune.

 

[M. Bachmeier]

You are probably correct. After all, how could a blast like the large column rising in the center of this photo lift and toss aside something as massive as a fuel handling machine. BTW, what is the approximate size of that, uh, kind of green looking . . . "what are you-call-it" or "thingamabob" falling there to the right of the massive vertical column of the blast at unit 3?

http://i306.photobucket.com/albums/nn270/tcups/Falling-FHM.jpg

BTW, did you catch the earlier extensive photo analysis back there a few days ago where several of us spent hours lining up the towers, the sun, and the buildings to figure out where that long, green looking thing came down? That may have been wrong too, I suppose.

Ya, let's calculate how much power could be in the blast?

Maybe "(60bar, 400C)= 3177.2 kJ/kg" or per liter. How many liters in primary containment at time of explosion? What was the pressure at the time of explosion? Either way it seems like enough power to put a small object in orbit...

See: http://me.queensu.ca/courses/MECH230/notes/documents/lect14-15.doc

 

[Homer Simpson]

post 3000. Holy cow.

Chinese, Japanese,Dirty Knees, Look at these... posts

 

[razzz]

This just in from TEPCO (May be a duplication)

At 5:38 am on April 6th, we observed the stoppage of the water spilling
from the crack on the concrete lateral of the pit. Details of the
situation will be announced after checking the blockage of the water
flows.

We will continue the countermeasure in order to prevent further outflow
of high level radioactive materials to the ocean.

From http://www.tepco.co.jp/en/press/corp-com/release/

Bob S

I'm glad they spotted the dye before it ended up in their coffee.

Laborer #1 & 2 will now be tasked to remove the 'injected' concrete (job security).

 

[yuriwho]

For those wondering where the oxygen can come from. Water can also be split into hydrogen and oxygen by temperature alone. It occurs above 2500 C and can be catalyzed by metal oxides which lower the temperature required. When the rods in the core are not covered with water, they can reach these temperatures and produce both hydrogen and oxygen even if the zirconium cladding is already burned.

see http://en.wikipedia.org/wiki/Water_splitting

edit added better link

 

[I_P]

"...
Among other problems, the document raises new questions about whether pouring water on nuclear fuel in the absence of functioning cooling systems can be sustained indefinitely. Experts have said the Japanese need to continue to keep the fuel cool for many months until the plant can be stabilized, but there is growing awareness that the risks of pumping water on the fuel present a whole new category of challenges that the nuclear industry is only beginning to comprehend.

The document also suggests that fragments or particles of nuclear fuel from spent fuel pools above the reactors were blown “up to one mile from the units,” and that pieces of highly radioactive material fell between two units and had to be “bulldozed over,” presumably to protect workers at the site. The ejection of nuclear material, which may have occurred during one of the earlier hydrogen explosions, may indicate more extensive damage to the extremely radioactive pools than previously disclosed. ..."

http://www.nytimes.com/2011/04/06/world/asia/06nuclear.html?_r=1&hp"

 

[razzz]

http://www.latimes.com/news/nationworld/world/la-fg-japan-nuclear-20110406,0,2697428.story"

Fishing of sand lances has been suspended. Local fishermen called on Tepco to halt the release of radioactive water into the sea and demanded that the company compensate them for their losses.

 

[AntonL]

This just in from TEPCO (May be a duplication)

At 5:38 am on April 6th, we observed the stoppage of the water spilling
from the crack on the concrete lateral of the pit. Details of the
situation will be announced after checking the blockage of the water
flows.

We will continue the countermeasure in order to prevent further outflow
of high level radioactive materials to the ocean.

From http://www.tepco.co.jp/en/press/corp-com/release/

Bob S

Now Tepco managed to dam the underground flow,
I wonder how long it will be for the next spring to appear.

 

[Jorge Stolfi]

And we never saw that wench again after the explosion.

There are some large orange-painted metal parts on the ground, between reactors #3 and #4, that could be pieces of the fuel handling machine. Additional pieces may have been covered by roof debris.

 

[yuriwho]

http://www.nytimes.com/2011/04/06/world/asia/06nuclear.html?_r=1&hp"

From the same article

The assessment provides graphic new detail on the conditions of the damaged cores in reactors 1, 2 and 3. Because slumping fuel and salt from seawater that had been used as a coolant is probably blocking circulation pathways, the water flow in No. 1 “is severely restricted and likely blocked.” Inside the core itself, “there is likely no water level,” the assessment says, adding that as a result, “it is difficult to determine how much cooling is getting to the fuel.” Similar problems exist in No. 2 and No. 3, although the blockage is probably less severe, the assessment says.

It's worth reading the whole article. Combined with the thermal production of hydrogen and oxygen from steam, this explains why they wanted to add N2 gas into the reactors.

 

[Jorge Stolfi]

Tepco do not understand their own measurements

I have asked this on twitter and got no answer, perhaps here: Does TEPCO have any nuclear engineers on its payroll? Or do they sub-(and subsub-)contract the entire operation of their nuclear plants?

 

[shogun338]

Is there any doubt at this point, that the pools are full of debris? And damage to the spent fuel rods is certain?

In the TEPCO helicopter flight over the Units the Helicopter spends the least amount of time over Unit 1 . My guess is radiation readings where so high he got out of there quick . But on the #1 video by TEPCO at 30 seconds the helicopter films what looks like left side of Unit 1 where the spent fuel pool should be and it is full of debris or covered with debris . At this 30 second mark you can see a bright red glow coming from a small point in this location . It looks like something is super heated on or under the debris at this point . If you go frame by frame in the video you can see it good . It stands out from everything else .

 

[tyroman]

@Homer Simpson

Excellent reference you posted!
http://canteach.candu.org/library/20044507.pdf

First question;
Most references I have seen give UEL at STP which would not apply within a hot - pressurized containment vessel... so, in Figure from R. Heck et al showing "Ignition tests performed with Siemens igniters." what were the temp/pressures for the tests? Can this be infered from the Steam Vol. % ?

Second question;
On the attached Heck diagram, how would you read the three Vol. % values for the point circled in red (just beyond the transition area)?

.

 

[ninefingers]

Now you have the mechanism for the initial fireball at the southeast corner, a ballistic FHM, damage to the equipment pool, blown out upper building, and blown out lower building including the access tunnel, all without a gross breech of the RPV (ie, melted fuel melting through the steel of the RPV).

Debunk that.


Last edited by TCups; T at 03:18 PM..

 

[ninefingers]

I know it's innappropriate but why do I keep hearing the William Tell Overture ? "BOOM!"

 

[Joe Neubarth]

That blog entry is correct. See also http://nucleardata.nuclear.lu.se/nucleardata/toi/nuclide.asp?iZA=520429 for data on Te-129m

The incredible thing is that Tepco do not understand their own measurements. See also http://www.nytimes.com/2011/04/06/world/asia/06tepco.html

Such a company should never have been allowed to operate a nuclear reactor.[/QUOTE

But that does not explain the blue glows above the reactor building.

 

[shogun338]

What is the long building in the background middle left ? It has no damage after tsunami . Now it looks like the end has been blown open .

 

[Emreth]

You are probably correct. After all, how could a blast like the large column rising in the center of this photo lift and toss aside something as massive as a fuel handling machine. BTW, what is the approximate size of that, uh, kind of green looking . . . "what are you-call-it" or "thingamabob" falling there to the right of the massive vertical column of the blast at unit 3?

http://i306.photobucket.com/albums/nn270/tcups/Falling-FHM.jpg

BTW, did you catch the earlier extensive photo analysis back there a few days ago where several of us spent hours lining up the towers, the sun, and the buildings to figure out where that long, green looking thing came down? That may have been wrong too, I suppose.

I've been following this thread since the beginning. I've seen all the analysis. The thing looks greenish but it might just be because it's in the shadow. I think it falls somewhere farther than the building anyway. The mushroom cloud is as wide as the building at this point and the object goes beyond.The remains of the FHM looks like scattered little pieces at the north end on the top view image.
There is probably enough force in the blast to launch an object that size but can that force be efficiently converted into momentum? I don't think so. The expanding gas when imparting the required acceleration to go that high would probably cause very high inertial forces that would rip it into small pieces, if the shock wave didn't already do it . It's like putting a dynamite next to it. Smaller pieces like the truss parts might survive it because they are lighter.
But maybe I'm wrong, FHM might be a very light structure welded out of bunch of metal sheets.

 

[razzz]

@Homer Simpson

Excellent reference you posted!
http://canteach.candu.org/library/20044507.pdf

Daams paper is interesting, seems a bit shortsighted in light of current events. Not design but possible outcomes. Saltwater and sand I didn't see addressed and (heated) brine is the worst when it comes to plumbing.

I only apply my extremely limited general knowledge towards it.

Suggests grating (air flow/venting) the floors instead of using solids (like concrete), now he tells us.

Suggest nitrogen gas will not cool as well as steam. That could be a problem if pressures are at the margins.

Only touched on dispersal concerning air temps and inversions. He did say, higher reaching plume the better. (I'm think'in stratosphere)

If they do inject nitrogen, I think they are trying to prevent more than just another hydrogen explosion...what could possibly go wrong?