Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[Quim]

Ok. Something guided that plume upwards. Looks like that to me as well. How does that make it necessary for a steam explosion to have happened?

Let's not jump too fast here.

Forget the steam explosion for a moment, let's try and figure what vectored energy upwards.

I see only two possibilities:

1. a shaped charge sort of effect which I see as very unlikely because it would have had to have formed such a perfect 360 degree containment (in 3 dimensions)

or

2. the blast was contained by the walls of the fuel pond.

There's any number of structures in there that could have shaped the blast.

I can think of nothing except the two I mentioned above.

 

[joewein]

Most recent JAIF report on Daini:
http://www.jaif.or.jp/english/news_images/pdf/ENGNEWS01_1307247746P.pdf

Of relevant interest within:

Appears there is still an 8km evac area around the plant.

The limit around Fukushima II was at 10 km when it became 20 km for Fukushima 1. Since the plants are about 11 km apart, very little of the 10 km radius around F-II was not also inside the 20 km radius around F-I. So when F-I achieved cold shutdown, instead of lifting its exclusion zone they simply shrank it to 8 km, which was a no-go area anyway by virtue of being inside F-I 20 km evacuation zone.

 

[tsutsuji]

Tepco provided more details to NISA about the water purification unit which is supposed to start running at Fukushima Daiichi in the coming days. The following attachment includes a number of diagrams, photographs and a map showing the locations of the facilities and the new tanks : http://www.meti.go.jp/press/2011/06/20110609002/20110609002-3.pdf

The desalinated water will be vaporized in the final step to reduce its volume.
http://www.asahi.com/english/TKY201106080177.html

If this can be done safely without releasing radiations into the atmosphere, would not a similar process be useful at Fukushima Daini and avoid angering the fishermen with a discharge into the sea ?

 

[zapperzero]

I can think of nothing except the two I mentioned above.

I can. For instance, some arrangement of gantry cranes, plus a wall or two might have thrown big "shadows", stopping much of the ejecta, while the rest went upwards. The outer walls of the reactor building may have reflected some of the blast, bunching up the debris cloud as it was forming. And so on and so forth.

Even if the SPF shaped the blast (which it may have), it does not follow that it was anything else but a hydrogen blast. The highest concentration of hydrogen would have been found directly above the pool, no? And the pool would have been only half-filled.

 

[zapperzero]

So when F-I achieved cold shutdown, instead of lifting its exclusion zone they simply shrank it to 8 km, which was a no-go area anyway by virtue of being inside F-I 20 km evacuation zone.

Does not compute. If all is well, why maintain a "fictional" exclusion zone?

 

[etudiant]

Tepco provided more details to NISA about the water purification unit which is supposed to start running at Fukushima Daiichi in the coming days. The following attachment includes a number of diagrams, photographs and a map showing the locations of the facilities and the new tanks : http://www.meti.go.jp/press/2011/06/20110609002/20110609002-3.pdf



If this can be done safely without releasing radiations into the atmosphere, would not a similar process be useful at Fukushima Daini and avoid angering the fishermen with a discharge into the sea ?

Is it even realistic to think of evaporating 100,000 - 200,000 tons of water, apart from the contaminated steam aspect?
Seems to me they might need to restart unit 5 or 6 to supply that kind of heating.

 

[robinson]

Does not compute. If all is well, why maintain a "fictional" exclusion zone?

Keeps out the reporters. And the crazies. Protesters early on rammed the gate and drove around Fukushima Diani for a good while (protesting loudly all the while) until they could catch them and arrest them.

Yes, in the middle of all the post quake/tsunami/meltdown at Daiichi, protesters breached the security at Diani and drove around inside the plant. In a truck.

The story wasn't played up of course.

 

[joewein]

Unit 5 is at atmospheric pressure so the question is if they are venting it science earthquake ? I understand that is RPV is closed (it must be during pressure tests) the pressure shouldn't be at atmospheric level.

Units 5 and 6 are in cold shutdown, i.e. coolant is below 100 deg C and therefore the RPV doesn't have to be beyond atmospheric pressure to prevent boiling. Decay heat is being removed using the RHR system.

 

[Borek]

I can. For instance, some arrangement of gantry cranes, plus a wall or two might have thrown big "shadows", stopping much of the ejecta, while the rest went upwards. The outer walls of the reactor building may have reflected some of the blast, bunching up the debris cloud as it was forming. And so on and so forth.

Even if the SPF shaped the blast (which it may have), it does not follow that it was anything else but a hydrogen blast. The highest concentration of hydrogen would have been found directly above the pool, no? And the pool would have been only half-filled.

Discussion on the explosion is already buried deep somewhere in this thread. From what I remember speed of the explosion propagation heavily depends on the shape of the area (walls, columns, any other objects). No idea if that's enough to shape the explosion so that it is mostly vertical (that is, up becomes the path of the least resistance), but who knows.

 

[robinson]

Building One: Hydrogen explosion.

Building Three. Hydrogen plus something else.

Building Four: Unknown.

 

[zapperzero]

Building One: Hydrogen explosion.

Building Three. Hydrogen plus something else.

Building Four: Unknown.

At least make an effort to argue or source... such pronouncements add nothing of value.

 

[rowmag]

The articles in question are in Japanese, so quoting would be limited to Japanese text and asking someone to translate. We might ultimately end up with the whole article translated, which would completely be against the fair-use spirit of limited reproduction of copyrighted works. Then there is the matter of Japanese copyright law which I am totally unfamiliar with.

Being able to read the text would be nice, but my inability to read Japanese is my problem, not the author or publisher's. For the 2 articles in question, that's OK though because the diagrams and pictures convey substantial information by themselves.

My personal opinion is that most of the text does not seem very interesting unless one is a hardcore civil engineering otaku. The juicy bits of relevance for this thread are mostly in the illustrations, as you note.

I was using Google Translate to get some idea of the article text, but it's slow going. For example, first article, first section, title is
"1. まえかき"
which google translates as "For Example Oyster Or". I gave up soon thereafter.

Try "まえがき."

 

[robinson]

At least make an effort to argue or source... such pronouncements add nothing of value.

Please give us a source for your claim.

:)

Thinking about Building Three, it is highly probable that the building was full of not just hydrogen, but a lot of moisture. (this probably came up before, but I don't recall it at the moment)

If the hydrogen level was high, there wouldn't be enough oxygen to allow it to all oxidize at once, which clearly Building One suffered from. So the initial blast which clearly blew out the side allowed oxygen rich air to suck in, and the rest of the hydrogen went, but at the same time heating the moisture inside to turn into superheated steam, which would explain the obvious steam explosion. Obvious in the sense it clearly was not the type of instant flash you would see with a big hydrogen/oxygen explosion alone.

Experiments with concrete models and hydrogen, and hydrogen and a lot of moisture might actually learn us something about what can happen when you combine superheated boiling water pools, hydrogen, burning nuclear fuel rods, cesium hitting water, and various oils, gases and such, when it all goes terribly wrong.

 

[robinson]

Back to Power plant two:

Although the utility known as TEPCO told the agency that it will release the water after removing radioactive substances to an undetectable level, the agency is not approving the plan, leaving the fate of the 3,000 tons of the water accumulated in the nuclear power station, located 15 kilometers south from the crippled Fukushima Daiichi power plant, undecided.

If the water remains in tanks for a prolonged time, the storage facility may be corroded by salt in the water.

After being flooded by tsunami following a magnitude 9.0 earthquake that struck northeastern Japan on March 11, the Fukushima Daini power station saw about 7,000 tons of water accumulate in its facilities.

Of the water, 3,000 tons in the reactor, turbine and other buildings has been found to contain a small amount of radioactive materials such as cobalt.

TEPCO initially planned to let the water stay in the tank, but changed its mind after seeing rust in the storage facility and decided to release the water into the sea.

http://mdn.mainichi.jp/mdnnews/news/20110608p2g00m0dm090000c.html

While I don't believe most of what TEPCO reports, much less after it is filtered through the Japanese Government, something clearly went seriously wrong at Daini as well.

What exactly happened there seems shrouded in mystery.

 

[zapperzero]

If the hydrogen level was high, there wouldn't be enough oxygen to allow it to all oxidize at once

There would, if the hydrogen were to have been created by radiolysis of water into H2 and O2.

 

[robinson]

Of course, but that isn't what is supposed to have happened. Hydrogen was produced by metals oxidizing, so the oxygen was locked up in metallic oxides, it wasn't electrolysis of water going on. If that had been the case, the explosions may have been much more destructive.

 

[tsutsuji]

The NISA has summarized a number of informations about the water treatment facility in http://www.meti.go.jp/press/2011/06/20110609006/20110609006-2.pdf (in Japanese).

That facility is meant to be an emergency facility running for one year, treating the 230,000 m³ that will have been produced until the end of 2011. After that a lasting facility could take over.

The 10,000 m³ contaminated water storage facility will be gradually built from mid August to the end of September.

2,000 m³ of radioactive sludge will be produced. 400 caesium absorption towers will be spent. The caesium absorption towers are installed in concrete box culverts. The sludge in pellet containers at the process main building. The absorption towers are designed to ensure that in a worse case scenario they don't heat more than 1°C per hour. The sludge will have a cooling system to remove the residual heat. Hydrogen production will be controlled with ventilation.

A series of precautions is listed against earthquakes. A 14 m high sea wall will be built to protect from tsunamis. All high level contaminated water equipments must be indoors with openings including doors being strong enough to resist tsunamis. The buildings must be watertight to prevent leaks into ground water... etc.

There is no fear of criticality, because no U or Pu is present in the water.

Measures against chemical hazards (explosions, worker's health) are defined.

By December, there will be a temporary storage facility for sludge. By September a temporary storage facility for spent caesium absorption equipments. A study for the end storage of the various waste products is started.

 

[zapperzero]

Of course, but that isn't what is supposed to have happened

According to whom?

 

[jim hardy]

Nuceng

thank you for the complete answer four pages back regarding PCV vent paths.

you painted a precise mental picture.

an aside - while catching up this am i noticed lots of conversation on H2.
here's another .gov study on it

Hydrogen Problems Related to
Reactor Accidents

hope i saved right link, it's a Danish study

http://www.iaea.org/inis/collection/NCLCollectionStore/_Public/25/028/25028788.pdf

it's too highbrow for me to understand

but some of you folks will devour it.

old jim

 

[tsutsuji]

Is it even realistic to think of evaporating 100,000 - 200,000 tons of water, apart from the contaminated steam aspect?
Seems to me they might need to restart unit 5 or 6 to supply that kind of heating.

According to the Mainichi quote written above at https://www.physicsforums.com/showthread.php?p=3347501#post3347501 the quantity angering the fishermen is only 3,000 tons. I don't really understand what is being planned for the other 7,000-3,000=4,000 tons. Is it so clean that Tepco is allowed to discharge it into the sea by the existing rules ?

 

[Bioengineer01]

I just now recalled that I posted this here, a month or so ago (#5257):

<<When TEPCO tells me it's 10% of Chernobyl, I'll assume it's most likely at least 20%, and I'm fairly sure that I at least won't be way high.
Could I be way low? Yeah, I suppose so, but I'll wait for better evidence to support that.
(And, if it *is* way low, there will surely be evidence of that, eventually. Even if it takes a while to seep out, so to speak.)>>

So what did they announce yesterday? That it's more like 20%.

(I'm now working off the assumption it's probably really more like 40%, but we'll see what happens.)

Again, if we apply Markov Chain prediction algorithms using the data already on the thread, worst case versus best case (normally officially supported by TEPCO), you can predict with 80% likelihood that it will be more than 40%, if I fix it at 40% then the probability level comes way down, difference between reported and "true" after two months situations predict a lot worse "true" scenarios. It was a fun exercise... :)

 

[Bioengineer01]

Well, it's certainly not thought to be linear.
TEPCO seems to suggest that it's been negligible after the first two weeks, so that initial total roughly equals THE total.

(Not that I necessarily *believe* that, but I think that's the 'official position.')

One thing I'm pretty confident of: the new number will eventually be exposed as nonsense, just like the old number was.

Then all the 'nuclear experts,' who pompously told us again and again that "this is nothing like Chernobyl; anyone who says it is is an idiot" are going to be even more red-faced than they already are.

And they should be mercilessly held to account for it.

My understanding is that the reported number DO NOT include releases to the Ocean and only air releases and thus the statement that the worse is over. When they consider the true releases to the Ocean, my gross napkin calculations say that they already got Gold!

 

[etudiant]

According to the Mainichi quote written above at https://www.physicsforums.com/showthread.php?p=3347501#post3347501 the quantity angering the fishermen is only 3,000 tons. I don't really understand what is being planned for the other 7,000-3,000=4,000 tons. Is it so clean that Tepco is allowed to discharge it into the sea by the existing rules ?

Apologies, there was confusion as to the items discussed.
The comment was in response to the Asahi quote in your posting 9418:
The desalinated water will be vaporized in the final step to reduce its volume.
http://www.asahi.com/english/TKY201106080177.html
which appeared to be in the context of the DaiIchi plant water treatment plan.

The 7000 tons at DaiNi seem to be quite an interesting issue in their own right, as the source of their contamination is not obvious. While one can hardly blame TEPCO for wanting to remove this radioactive seawater from their premises, the pattern of disclosure is once again not such as to inspire confidence.

 

[robinson]

Since the concern is that it is salt water, no doubt from tsunamis, and that it is contaminated raises a host of questions.

 

[Bioengineer01]

I am one of the people who don't believe that a hydrogen explosion could have caused the vertical blast we see in the unit 3 explosion, but it is not because I don't believe a hydrogen explosion would be limited in power. To my eyes, the explosion, or the second part of the explosion of unit three, was a vectored blast.

I don't see the "mushroom cloud" as being merely a case of heat rising and carrying with it contaminates from a blast (as is the case in a surface burst nuclear explosion.) I see the vertical cloud as being the actual product of the blast itself. Imagine if you took all the shot out of a shotgun shell, replaced it with a dark powder of some sort and fired it into the air - that effect is what I see in the unit three blast,

I apologize if this explanation sounds too elementary or condescending but there are obviously some here who don't understand the significance of a vectored vertical blast - some force or some structure was responsible for containing the explosive force to a single direction.

The reactor containment structure can be ruled out as the vectoring agent simply because the equipment crane is lying on top of the containment structure with the remnants of the roof laying on top of that. These would not be so if the vertical blast had originated from the RPV or its containment,

The unit three explosion has to be seen as a two part event, a hydrogen blast (which did in fact break steel-reinforced concrete pillars) and a vectored vertical blast.

To jumble these two events and see them both as a single "explosion" would be to ignore the visual evidence.

Hold a second and sorry if it is just another stupid comment on my part, but if it wasn't the containment that vectored the detonation (second phase), for that amount of vertical energy to be generated you'd need fusion level releases of energy from the SPF, since the pool is such a poor vertical vectoring structure. Is it conceivable that the pressure wave from the first detonation could have triggered a fusion reaction? Or am I having a serious senior moment here?

 

[Bioengineer01]

Discussion on the explosion is already buried deep somewhere in this thread. From what I remember speed of the explosion propagation heavily depends on the shape of the area (walls, columns, any other objects). No idea if that's enough to shape the explosion so that it is mostly vertical (that is, up becomes the path of the least resistance), but who knows.

Seems easy to model using finite elements. From modelling experience, I'd be willing to bet that only a reinforced steel/concrete structure could have contained the blast to only one direction, the forces involved to reach the heights shown in the video are enormous. Which brings me to the second problem, and that is you can also apply inverse modeling and estimate the amount of energy release required to create that size vertical blast vectored by pool of the dimensions of the SFP and you come up with numbers that are too large for hydrogen to generate in a single blast... The estimation gets even to the ridiculous level if you assume that the detonation came from the top third of the pool. The vertical trajectory is too short and the expansion wave would quickly disperse sideways. I wish I had access to some finite element modeling tools. If somebody has the time, this will make for a quick paper...

 

[Bioengineer01]

At least make an effort to argue or source... such pronouncements add nothing of value.

Source is thread consensus. I'd add to that pronouncement, Hydrolysis as the most likely source for SFP4. Not definitive, but current status of understanding of the most likely scenarios. Definitive proofs will have to wait a lot longer, may be 10 years or more. Solid hypothesis that fit most of the available data is the best we can possibly hope for at this stage. Also, in science, you quickly learn that you can only be proven wrong.

 

[Bioengineer01]

Back to Power plant two:

http://mdn.mainichi.jp/mdnnews/news/20110608p2g00m0dm090000c.html

While I don't believe most of what TEPCO reports, much less after it is filtered through the Japanese Government, something clearly went seriously wrong at Daini as well.

What exactly happened there seems shrouded in mystery.

I was wondering the back side of your statement: "Who trusts TEPCO today?" And believe it or not I came up with an answer: "Those who haven't yet sold their shares" :)

 

[robinson]

Haha! But out of respect for the forum and the staff, I try to avoid non physics stuff in this thread.

 

[ElliotLake]

I think that 10% was for a 30 day time frame. The cumulative totals must be near 50% by now and continues to tally up.

Indeed:
Radiation understated after quake, Japan says

Japan said Monday that radioactive emissions from the stricken Fukushima Daiichi nuclear power plant in the early days of the March 11 earthquake and tsunami disaster might have been more than twice as large as a previous estimate, suggesting the accident was more grave than the government had publicly acknowledged. [...]

The agency also said it now estimated that the radioactive release from the plant totaled 770,000 terabecquerels in the first week after March 11. [...]

The agency suggested that the higher emissions estimate was equivalent to only about 10 percent of the radioactive materials released in 1986 by the explosion and fire at Chernobyl [...] But the 770,000 terabecquerels figure in fact comes to about 40 percent of the official Soviet estimate of emissions from Chernobyl. [...]

Officials cautioned that there was a wide margin of error involved [...]

http://www.nytimes.com/2011/06/07/world/asia/07japan.html?_r=1

 

[elektrownik]

But they count only air release ? Or water also ?

 

[Bandit127]

If you postulate a fuel air explosion, why do you need a steam explosion too?

Nobody needs a steam explosion. But we do need to try to understand what happened.

If the underpressure was -0.6 Bar(g) the water in the spent fuel pool at about 80°C (if I remember correctly) would have very rapidly exceeded its boiling point. Creating rapidly expanding steam.

I can only guess that the effects would have happened firstly at the speed of sound in water (the underpressure) then at that speed in air (expanding steam).

 

[clancy688]

But they count only air release ? Or water also ?

Only air.

 

[mscharisma]

Back to Power plant two:

http://mdn.mainichi.jp/mdnnews/news/20110608p2g00m0dm090000c.html

While I don't believe most of what TEPCO reports, much less after it is filtered through the Japanese Government, something clearly went seriously wrong at Daini as well.

What exactly happened there seems shrouded in mystery.

Fwiw, I've gone through the TEPCO press releases (though not the Japanese appendices) relating to Daini, going backwards to, so far, April 13, since it puzzled me that "suddenly" there was a radioactive-water-in-the-basement problem and supposedly ongoing negotiations between TEPCO and government about release into the ocean after some decontamination.

While TEPCO reported a fire on May 27, an air leak on June 8, and an oil leak into the sea on June 9, nothing mentions or deals with accumulated water, radioactive or not, until April 13, although it may very well be in press releases prior to that, which I haven't read yet. In that April 13 press release, it is mentioned that TEPCO has to report to NISA about various aspects of the impact of the tsunami by July 8.

April 13 regarding tsunami impact:
http://www.tepco.co.jp/en/press/corp-com/release/11041304-e.html

May 27 regarding fire:
http://www.tepco.co.jp/en/press/corp-com/release/11052708-e.html

June 8 regarding air leak:
http://www.tepco.co.jp/en/press/corp-com/release/11060808-e.html

June 9 regarding oil leak:
http://www.tepco.co.jp/en/press/corp-com/release/11060907-e.html

And then this, also April 13:
http://www.tepco.co.jp/en/press/corp-com/release/11041303-e.html
"Regarding the earthquake occurred at 2:07 pm on April 12th (previously
announced in the press release "Plant conditions after the earthquake"
on April 12th), we have been inspecting the plant, however, no trouble on
the plant facilities has been detected.
The figures indicated at exhaust stack monitors and monitoring posts at
the station boundary are within the usual range, and there is no influence
of radioactivity outside as of now."

Maybe "no trouble" only relates to release of radioactivity?

EDIT: Plant status as of April 11 here (and at least I don't see anything about water in the basement anywhere. ?):
http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110411e9.pdf

 

[razzz]

Can someone look at my post about unit 5 here: https://www.physicsforums.com/showpost.php?p=3346232&postcount=9333
I don't understand still what they were doing there, if the reactor was at 7MPa it must be on ? I don't remember information about scram in unit 5, it was reported always as cold shutdown

I'd like to thank the more experienced and knowledgeable persons for explaining the Unit 5 situation at the time in question. I can only at best give a general response bit since he felt ignored I thought I'd better say something. Can't blame him for wondering why another unit could have failed.

I started reading the .pdf Govt Report to IAEA - June 2011 but can't get past the geology, quake and tsunami data. It just all just seems pointless after those pages.

Edit: I took the time to inquire within the US Geological Survey site by asking a question in which they don't have to respond to but they did as follows...

Hi,

Thank you for your question. Sadly, you read the report correctly. The coast of Japan did sink a bit, in addition to moving in a easterly direction during the earthquake. The subduction at the coastline really reduced the effectiveness of all of the tsunami walls, and of course, the result was devastating.

regards,

Brian Kilgore
US Geological Survey

 

[tsutsuji]

Fwiw, I've gone through the TEPCO press releases (though not the Japanese appendices) relating to Daini, going backwards to, so far, April 13, since it puzzled me that "suddenly" there was a radioactive-water-in-the-basement problem and supposedly ongoing negotiations between TEPCO and government about release into the ocean after some decontamination.

While TEPCO reported a fire on May 27, an air leak on June 8, and an oil leak into the sea on June 9, nothing mentions or deals with accumulated water, radioactive or not, until April 13, although it may very well be in press releases prior to that, which I haven't read yet.

The inundation caused by the tsunami wave was mentioned in the April 9 report :http://www.tepco.co.jp/en/press/corp-com/release/11040910-e.html with attachment http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110409e10.pdf where a photograph shows water on the floor of the heat exchanger building. But this water is not supposed to be contaminated.

So I feel surprised by the recent announcement that there is a contaminated water problem at Fukushima Daini.

On the other hand, is it much more surprising than the presence of contaminated water at Fukushima Daiichi unit 6 ? Or at any garden pond or swimming pool in the nearby cities and villages ?

 

[elektrownik]

On the other hand, is it much more surprising than the presence of contaminated water at Fukushima Daiichi unit 6 ? Or at any garden pond or swimming pool in the nearby cities and villages ?

Yes there is 13500m3 in unit 6 (t/b 9500, r/b 4000) and only 300m3 in unit 5... Torus level is flooded and ground floor around 15cm

 

[tsutsuji]

Edit: I took the time to inquire within the US Geological Survey site by asking a question in which they don't have to respond to but they did as follows...

"you read the report correctly

Can you please provide an internet link to that report ?

 

[mscharisma]

The inundation caused by the tsunami wave was mentioned in the April 9 report :http://www.tepco.co.jp/en/press/corp-com/release/11040910-e.html with attachment http://www.tepco.co.jp/en/press/corp-com/release/betu11_e/images/110409e10.pdf where a photograph shows water on the floor of the heat exchanger building. But this water is not supposed to be contaminated.

So I feel surprised by the recent announcement that there is a contaminated water problem at Fukushima Daini.

On the other hand, is it much more surprising than the presence of contaminated water at Fukushima Daiichi unit 6 ? Or at any garden pond or swimming pool in the nearby cities and villages ?

Thank you. Just to clarify: I was by no means suggesting the water is not there or not from the tsunami. My intent rather was to point out how this water and how to deal with it has been a non-topic by TEPCO, the Japanese government, or the press for quite a while. Maybe I should have made that clearer, my apologies. Especially since it is now claimed to be contaminated in a most illogical fashion with the source unknown, I find the overall picture the silence paints rather suspicious. And I'm hoping that you scientific-minded folks here will keep an eye on it all.

 

[SteveElbows]

My understanding is that the reported number DO NOT include releases to the Ocean and only air releases and thus the statement that the worse is over. When they consider the true releases to the Ocean, my gross napkin calculations say that they already got Gold!

Care to share your rough calculations?

At the moment I have an issue with people stating that releases must be 50% or more of Chernobyl by now. They might be, I don't have problem imagining such a possibility, but I don't remember seeing evidence that makes this a relatively safe bet.

How much do we think got into the sea? I understand the estimate for the radiation in the water that is still in basements & trenches or moved to storage is about the same as the estimated air release. But I don't remember any good estimates for what's already gone into the sea.

I can't help but be a bit grumpy about this stuff at the moment because although its very important and I expect the reality is quite bad, I am not happy that the doubling of an estimate is being treated as news that radioactive release is worse than we thought weeks ago. Its mostly the media I am unhappy with about this, although it may have happened a little on this forum too. I mean seriously, the estimate that was recently increased was the one that was ignored when it first came out because it was the lower of two estimates that came out at about the same time, and the other higher one was not so far off the new 'double' estimate we now have. So its really not double the number most of us would of had in our minds weeks ago.

 

[jlduh]

I see that according to latest plant parameters, they measured unit 4 fuel pool temperature at 19:52 on the 8th June and it was 86-88 degrees C.

http://www.tepco.co.jp/en/nu/fukushima-np/f1/images/11060906_table_summary-e.pdf

This is confirmed by above than normal steam out of N°4 currently on Tepco webcam...

http://www.tepco.co.jp/nu/f1-np/camera/index-j.html

 

[SteveElbows]

Especially since it is now claimed to be contaminated in a most illogical fashion with the source unknown, I find the overall picture the silence paints rather suspicious. And I'm hoping that you scientific-minded folks here will keep an eye on it all.

I remain open-minded about this, but I won't go as far as to say that the official claim is totally illogical.

By this I mean that I probably should not be surprised if I give a nuclear power plant a bit of a wash with tsunami water, I would expect a variety of 'normal' low level contamination from certain parts of the plant could well end up in that water.

To significantly reduce the plausibility of this possibility, I think we would need to see water that is much more severely contaminated than the sorts of numbers they have mentioned so far indicate is the case here?

 

[Joe Neubarth]

With all respect, that theory seems to me intensely implausible.
The explosion in reactor 3 was a coarse detonation, leaving huge chunks of stuff flying through the air.
Had it tossed out bits of the fuel from the SPF, one would expect fuel rod assemblies among the debris, not microscopic traces so minute that it takes effort to distinguish them from bomb test fallout.
Imho, the scenario of vapor leaks from the molten fuel in reactor 1 fits the data much better.

I saw a small segment of a video of the SFP for Reactor Three, and it looked like the Fuel assemblies were in place with a lot of debris on top of them. Has anybody seen anything else that would indicate that the spent fuel was exploded out of the pool?

 

[elektrownik]

I saw a small segment of a video of the SFP for Reactor Three, and it looked like the Fuel assemblies were in place with a lot of debris on top of them. Has anybody seen anything else that would indicate that the spent fuel was exploded out of the pool?

You mean reactor 4 ? In unit 3 we didnt saw fuel because of big debris...

 

[Joe Neubarth]

You mean reactor 4 ? In unit 3 we didnt saw fuel because of big debris...

The debris was scattered on top of the fuel assembly tops. They all looked in place to me. The rectangular patterns are quite distinctive. The only thing is that we only saw about two - three square feet of the top of the assemblies. The key in the video is to look quickly at the very beginning. As the bubbles come up and block the lens you can see the pattern of the top of the assemblies at the top and left of center. That rectangular pattern was consistent with the pattern in the reactor 4 SFP.

http://www.dailykos.com/story/2011/05/11/974605/-Up-Date-with-SFP-3-Video

 

[mscharisma]

I remain open-minded about this, but I won't go as far as to say that the official claim is totally illogical.

By this I mean that I probably should not be surprised if I give a nuclear power plant a bit of a wash with tsunami water, I would expect a variety of 'normal' low level contamination from certain parts of the plant could well end up in that water.

To significantly reduce the plausibility of this possibility, I think we would need to see water that is much more severely contaminated than the sorts of numbers they have mentioned so far indicate is the case here?

Mainichi article and translation on the ex-skf site (http://ex-skf.blogspot.com/2011/06/fukushima-iis-contaminated-water-cobalt.html):

"The water is from the tsunami [on March 11], and it contains radioactive cobalt-60 which probably came from the rusty pipes, and cesium-137 and cesium-134 which are considered to have flown from Fukushima I Nuclear Power Plant 10 kilometers north."

The trouble is, "to have flown in" could mean did fly (through the air sometime after the tsunami, but as mentioned in this forum previously, it's strange to end up in a basement) or did flow (through water, but as previously discussed, not likely possible at time of tsunami). The passive voice ("are considered to have flown") leaves it open whose consideration that is, but suggests that it is not considered (by whomever) to be from the plant site itself. And there's no word from TEPCO on it or, as far as I could find anyway, from NISA or IAEA.

Maybe others can also comment on how likely the isotopes detected are to originate from the plant site itself WITHOUT any fuel damage, containment problems, etc.? Thanks.

 

[razzz]

Can you please provide an internet link to that report ?

I used Mice and Men's link http://min.us/mvoVGLP" for the Govt Report to IAEA - June 2011 which is being referenced and quoted now as 'official.' The quake and other related data is in Chapter or Heading III were interesting to me.

 

[Bioengineer01]

Haha! But out of respect for the forum and the staff, I try to avoid non physics stuff in this thread.

No disrespect meant! Just trying to break the ice, same as if we were discussing around a table :)

 

[MiceAndMen]

My personal opinion is that most of the text does not seem very interesting unless one is a hardcore civil engineering otaku. The juicy bits of relevance for this thread are mostly in the illustrations, as you note.

Try "まえがき."

Wow, that's quite a difference. It took me a while to even see the slight difference in one of the glyphs. The translation I came up with is from "copy and paste" directly from the document into Google. For some reason the character/glyph/kanji is not correct. The good news is I won't be wasting a lot of time in the future on this activity. Natural language translation have a long way to go.

 

[Quim]

The debris was scattered on top of the fuel assembly tops. They all looked in place to me. The rectangular patterns are quite distinctive. The only thing is that we only saw about two - three square feet of the top of the assemblies. The key in the video is to look quickly at the very beginning. As the bubbles come up and block the lens you can see the pattern of the top of the assemblies at the top and left of center. That rectangular pattern was consistent with the pattern in the reactor 4 SFP.

Could you provide us with a link to a video which shows anything but chaos in the #3SFP?