Japan Earthquake: Nuclear Plants at Fukushima Daiichi

[jlduh]

Strange picture on Tepco site, showing "High dose rubble in the west side of Unit 3 reactor building of Fukushima Daiichi Nuclear Power Station"

http://www.tepco.co.jp/en/news/110311/images/110605_02.jpg

The high dose is (only) 12 mSv/h, this is concrete apparently covered with green spray of dust inhibitor but the grass around doesn't have any of this spray, which leads me to conclude that this rubble has been laid on the grass after being sprayed elsewhere and removed from it's original place. So, they consider it high enough to remove it but just lay it in the grass like that, not even on a pile but just neatly spaced like we see it? Or is it from the explosion that took place recently (but it was close to waste water treatment plant it seems, not west of N°3) that moved this already sprayed rubble?

Something is screwed in this picture...

 

[jlduh]

In my opinion, EX-SKF misunderstands the data he found. Those are only mathmatical simulations as for how a cloud of Krypton-85 would've behaved if there would've been one.

There are only two things we can derive from those images: Direction of a possible Krypton-85 plume that day and densitiy over distance based on initial release.
It doesn't show us what really happened.

Krypton-85 is a noble gas. It has a very, very, very short biological half life (the body throws it out as soon as it gets in) and is a beta decayer (it's only a problem if it's inside), so there is probably little to none significance for any health damage.
The nuclear waste facilities Sellafield and La Hague are releasing Krypton gas in the magnitude of hundreds of PBq every year. The converted release of C137 and I131 at Fukushima was 630 PBq. The conversion factor for noble gases (Krypton-85) is zero. (according to the INES manual)
So IAEA is apparently thinking of Krypton-85 as "not dangerous at all".

More on Krypton 85 (not a pure beta emitter, also gamma?)
http://www.ead.anl.gov/pub/doc/krypton.pdf

External dose coeff:

http://www.hc-sc.gc.ca/ewh-semt/pubs/radiation/dose/appendix-c-annexe-eng.php

it's 2,55 x 10-16 Svs-1Bq-1m3 for krypton 85. Not zero?

 

[Borek]

the grass around doesn't have any of this spray

Grass grows, I guess it was sprayed a month or so ago, but it went through the layer of the spray since.

 

[MiceAndMen]

Strange picture on Tepco site, showing "High dose rubble in the west side of Unit 3 reactor building of Fukushima Daiichi Nuclear Power Station"

http://www.tepco.co.jp/en/news/110311/images/110605_02.jpg

The high dose is (only) 12 mSv/h, this is concrete apparently covered with green spray of dust inhibitor but the grass around doesn't have any of this spray, which leads me to conclude that this rubble has been laid on the grass after being sprayed elsewhere and removed from it's original place. So, they consider it high enough to remove it but just lay it in the grass like that, not even on a pile but just neatly spaced like we see it? Or is it from the explosion that took place recently (but it was close to waste water treatment plant it seems, not west of N°3) that moved this already sprayed rubble?

Something is screwed in this picture...

What I noticed was the red piece of rubble at the base of the cone. I think that is another example of how they mark the radioactive sources with red paint. The pieces in the picture look like chunks of concrete. Maybe one of the remote-control rubble clearing vehicles just happened to dump its contents on that patch of grass. On the other hand, it does look rather neat, so maybe it was arranged there somehow.

 

[GJBRKS]

Hi to all.
I run a rapid back of the envelope calculation on the CS137 quantity TEPCO estimated.

If I got it right from Wolfram Alpha the activity of CS137 is 3.214 TeraBq/gram.

Having TEPCO estimated overall CS137 at 720,000 TeraBq, that would lead to 720,000/3.214=224,020 grams of CS137.

I then tried to understand in what relation that value is in respect to the total CS137 inventory that can be expeced from 1,2,3 cores.

I know this has been much more accurately estimated somewhere before in this 3d but I unfortunately do not have the possibility of searching the whole discussion right now.

However from wiki I got a fission yield of 6.0899% for CS137. That yield together with the mass ratio of U235 vs CS137 leads me to estimate in about 6.26 tonns the amount of U235 that has to undergo fission to pruduce this amount of CS137 (224,020/0.060899*235/137 grams).

Now if I remeber correctly at 32% of thermal efficiency 1 tonn of U235 has to undergo fission to produce 1 Gigawatt for one year.

Being almost exactly 2 gigawatts the overall power output of the concerned units, it would seem that the estimated CS137 already in the water is in the order of magnitude of 3 yrs worth of fission process.

In other words that would lead me to think that this estimates means that much of the molten fuel is already soluted in water.
On the other hand this conclusion, in a way reassuring, seems unreaalistic to me.

what I am I doing wrong ?
what do you think ?
thanks in advance

The 720,000 TeraBq estimate is for the total amount of ALL radioactive substances , not JUST Cs-137 :

http://www3.nhk.or.jp/daily/english/03_31.html

TEPCO says that by May 31st, 105,100 tons of waste water had accumulated. It contains an estimated 720,000 terabecquerels of radioactive substances. Tera stands for one trillion.

 

[Borek]

What I noticed was the red piece of rubble at the base of the cone.

Which makes me think - perhaps what is radioactive is JUST this piece painted red. Note how there is no grass around, but it grows without a problem just inches away.

 

[MiceAndMen]

Which makes me think - perhaps what is radioactive is JUST this piece painted red. Note how there is no grass around, but it grows without a problem just inches away.

I knew someone would point that out and I have to agree.

 

[joewein]

I propose encasing it (them) in a ten meter thick* cocoon of dry sand.
You propose pouring water on it .
Right?

Shall we continue from there?*(ten meter radius around each corium at minimum)

What would be the point of that? The sand would get hotter and hotter as the corium continuously produces more heat than the sand would conduct away, eventually melting the sand into liquid quartz glass. At least the water removes heat when it turns into steam and gets replaced with fresh water. Sand is a pretty good insulator and concrete is almost as good.

I came across this article with a back of the envelope calculation of how well concrete would do when in contact with a melted core after an accident:

http://www.cavendishscience.org/bks/nuc/quests.htm

The example there assumed a 1 GW electrical = 3 GW thermal reactor with 0.5% of thermal output as decay heat 14 days after shutdown = 15 MW. Spreading this heat output over a 1200 m2 slab of concrete 3 m thick, the author reckoned no more than 5% of the decay heat could be conducted away through the concrete even after the top of the slab reached 1800 deg C. Now unit 1 is about half the power output of the example reactor and the decay has progressed further, but the containment and therefore the concrete slab underneath is much, much smaller than the 140 foot = 40 m diameter in the sample. The RPV diameter of unit 1 is only 4.8 m in diameter, so I imagine the fuel would not spread out much wider initially after melting through the bottom of the RPV. The flat concrete bottom of the "light bulb" shaped containment measures about 10 m in diameter.

 

[etudiant]

There is an excellent writeup posted on EX-SKF website regarding the AREVA water treatment plant.
In the comments section, there is a very useful article, in French, regarding the ion exchange material, which is supplied by an Irvine, CA company called Kurion. They claim 100,000 to 1 selectivity for cesium and also offer an on site vitrification for the contaminated medium. Does anyone have any experience with this supplier or their material?

Article here: http://bourse.lci.fr/bourse-en-lign...ews=BNW110603_00005559&numligne=0&date=110603
Original EX SKF article here: http://ex-skf.blogspot.com/2011/06/contaminated-water-at-fukushima-nuke.html#comments

 

[biffvernon]

Which makes me think - perhaps what is radioactive is JUST this piece painted red. Note how there is no grass around, but it grows without a problem just inches away.

If it was just the one piece of rubble wouldn't the put a lead cover on it?

 

[elektrownik]

The question is why they show this us, it is nothing big, only 12 mSv... there is much more and higher radioactive debris around reactors
Also 12mSv shouldne kill grass, or there miss at last one zero
Maybe this can help locate this point: http://www.tepco.co.jp/en/nu/fukushima-np/f1/index3-e.html
Wow they found 950mSv, and 550mSv: http://www.tepco.co.jp/en/nu/fukushima-np/f1/images/f1-sv-20110605-e.pdf

 

[jlduh]

Grass grows, I guess it was sprayed a month or so ago, but it went through the layer of the spray since.

Look at the (small) areas of brown soil, no trace of green spray either. If this has been washed away by rain, why not the concrete rubble?

 

[Borek]

If it was just the one piece of rubble wouldn't the put a lead cover on it?

What for? At the moment it is marked, stabilized with the antidusting agent and probably in a place where it doesn't pose any kind of risk. 12 mSv/hour is not that much, especially if it is not in a place frequented by people. I guess it is 12 mSv/h measured with radiometer put close to the object, if you are several meters from it activity is orders of magnitude lower. Sooner or later they will start collecting radioactive rubble from such places, at the moment they most likely concentrate on cleaning places where there is urgent work to be done.

 

[Borek]

Look at the (small) areas of brown soil, no trace of green spray either. If this has been washed away by rain, why not the concrete rubble?

I would guess what was sprayed was grass that later died around the radioactive object. However, that leaves us with the question - why the dying grass was not kept in the place by the spray? Probably it keeps much better on relatively stable surfaces, than on something elastic.

 

[jlduh]

The question is why they show this us, it is nothing big, only 12 mSv... there is much more and higher radioactive debris around reactors
Also 12mSv shouldne kill grass, or there miss at last one zero
Maybe this can help locate this point: http://www.tepco.co.jp/en/nu/fukushima-np/f1/index3-e.html
Wow they found 950mSv, and 550mSv: http://www.tepco.co.jp/en/nu/fukushima-np/f1/images/f1-sv-20110605-e.pdf

Well, I share all your views, you avoided me to write it!

To tell you the truth, if i posted this image at first with the comments I did, it was because I also share as a possibility the fact that this picture has been "arranged" for communication purposes, especially when you discover that in parallel, as you said, in the last map before this one (28 may), these VERY VERY VERY VERY high dose rubble (if I want to compare with this "high dose rubble of 12 mSv/h! ) of 950 and 550 mSv/h were not reported!

So basically they find 550 and 950 mSv/h rubble, and they communicate with a "nice" picture of a "high dose rubble" of 12 mSv/h? Guys, if they put a cone on every little bit of concrete like this one (the red one) with 12mSv/h or more, i can tell you that the all plant is going to be flooded with cones in addition to water...

 

[Borek]

They don't post pictures - it is wrong.

They post pictures - it is wrong.

I think you are trying to make way too much from random facts. And it is not something that fits this thread.

 

[jlduh]

I would guess what was sprayed was grass that later died around the radioactive object. However, that leaves us with the question - why the dying grass was not kept in the place by the spray? Probably it keeps much better on relatively stable surfaces, than on something elastic.

Well, if i follow your hypothesis, it would mean that on all soil or grass surface this dust inhibitor is wery easily washed away by water which is not a good news for rainwater contamination after rainfall on the site (or they will have to respray every time after some rain...).

Also i have a hard time to imagine that the grass can grow and be so green with this inhibitor on it once it is spread ( just put a tent on the grass for some days and you will see that the grass is yellowing very quickly: grass needs light to grow for photosynthesis!).

So again i have a hard time to believe this area has been sprayed with green product...

 

[Borek]

Well, if i follow your hypothesis, it would mean that on all soil or grass surface this dust inhibitor is wery easily washed away by water

Not necessarily. Grass leafs were most likely covered with substance on one side only, when the grass died and started to crumble, this "paint" lost support and was washed away. It doesn't mean it won't hold on sand.

Also i have a hard time to imagine that the grass can grow and be so green with this inhibitor on it once it is spread ( just put a tent on the grass for some days and you will see that the grass is yellowing very quickly: grass needs light to grow for photosynthesis!).

You are underestimating grass. In a shadow it becomes yellow - yes, but given a chance it will break the surface of the substance it is covered with, once it is on other side, it grows as if nothing have happened.

So again i have a hard time to believe this area has been sprayed with green product...

Rubble around IS green, so it was covered with something.

 

[GJBRKS]

Well, I share all your views, you avoided me to write it!

To tell you the truth, if i posted this image at first with the comments I did, it was because I also share as a possibility the fact that this picture has been "arranged" for communication purposes, especially when you discover that in parallel, as you said, in the last map before this one (28 may), these VERY VERY VERY VERY high dose rubble (if I want to compare with this "high dose rubble of 12 mSv/h! ) of 950 and 550 mSv/h were not reported!

So basically they find 550 and 950 mSv/h rubble, and they communicate with a "nice" picture of a "high dose rubble" of 12 mSv/h? Guys, if they put a cone on every little bit of concrete like this one (the red one) with 12mSv/h or more, i can tell you that the all plant is going to be flooded with cones in addition to water...

Maybe this was the most photogenic of all rubbles.

The photographer has his/her individual motivations for taking that shot.

Perhaps the extraordinarity of the frame made the picture

It would look rather good on flickr

 

[swl]

Perhaps the debris was arranged in this manner to facilitate classification of the pieces based on radiation. Could they have used a gama camera to take a picture of the group to verify that none of the pieces are too hot or cool to be in the group? I would imagine it would be hard to measure individual pieces if they were all in a heap. So they just had a contract truck driver from Osaka spread them out nice and neat.

 

[ManuBZH]

First post... Thanks to everyone for these wonderful threads full of insights on Fukushima situation!

About this mysterious "highly" radioactive rubble, 12mSv probably stands for airborne radiation. The surface must be alot more radioactive. IMHO, the warning message and cone is fully justified as staying near this area would lead to significant external exposure.

 

[SteveElbows]

unit 1 SPF 650mm but at 6/5 05:00am, fuel should be exposed now or not long from now

As I keep saying on this thread, the reported level is the level of the skimmer surge tank, not the fuel pool.

The only thing these readings tell us for sure is that water level in skimmer tank is decreasing, which could be for several reasons, and that they have not refilled the fuel pool to the point where it overflows into the skimmer tank for some days now. This data does not tell you how far above the top of the fuel the water in the pool is.

 

[SteveElbows]

To tell you the truth, if i posted this image at first with the comments I did, it was because I also share as a possibility the fact that this picture has been "arranged" for communication purposes, especially when you discover that in parallel, as you said, in the last map before this one (28 may), these VERY VERY VERY VERY high dose rubble (if I want to compare with this "high dose rubble of 12 mSv/h! ) of 950 and 550 mSv/h were not reported!

If they behave this way then why would they bother to report the 950 & 550 mSv rubble at all? And why in the past did they bother to report the 1000mSv rubble south of reactor 3, and photograph it?

The fact that high radiation rubble is missing from some site surveys and is then discovered and published later on is hardly surprising or cause to suspect coverup. The maps have evolved over time, with detailed numbers changing, although the rough locations of some of the worst debris has long been known talked about, and these high numbers that get published usually fit this existing picture well.

 

[elektrownik]

As I keep saying on this thread, the reported level is the level of the skimmer surge tank, not the fuel pool.

The only thing these readings tell us for sure is that water level in skimmer tank is decreasing, which could be for several reasons, and that they have not refilled the fuel pool to the point where it overflows into the skimmer tank for some days now. This data does not tell you how far above the top of the fuel the water in the pool is.

yes but we can see that something changed:
data from 5/16 to 6/5 measured 2 times per day

 

[andybwell]

Japanese government minister with his own reasons for speaking certainly, however I believe he thinks he is being truthful...

"Some day we may not be able to live in Japan. There is the possibility that the power plant can reach the state of criticality again. If it explodes, it’s a huge matter. Radiation is being leaked in order to keep the reactors from exploding. So, in this sense, it’s even worse than letting the power plant explode. Radiation is going to be flowing out for a long period of time. This is not a matter of money, but of life and death for the Japanese. If Japan cannot be saved, then the people of Japan are done for. We can always print money. Ultimately the people will have to bear the burden. Government must be determined to put a stop to radioactive pollution no matter what it takes, money or otherwise. The Japanese people must understand the situation...

 

[andybwell]

That link is dead, andy, and I respectfully suggest that what you posted may violate the copyright of whatever source you got it from. That is way more than a 'fair use' amount of quoting there. Maybe you could find a better link and trim the quoted part?

Edit: It looks like you got if from chrismartenson.com and you basically quoted the entire "Part 2 of Arnie Gundersen Interview: Protecting Yourself If The Situation Worsens". I'm not going to hit the 'report' button on you, but you should really consider editing that post. We can all click on a link to what Gundersen has to say if we choose.

Do you honestly think that Arny Gundersen is painting an inaccurate tapestry? If so, please paint me an accurate one, and give me links to get accurate information.

 

[jim hardy]

They don't post pictures - it is wrong.

They post pictures - it is wrong.

I think you are trying to make way too much from random facts. And it is not something that fits this thread.

Most people are not devious.

Stuff looks freshly placed to me. Maybe it was a staged-for-press photo...
but putting myself in the shoes of a plant radiation-protection guy ---

IF i had a 12 msv (1.2R in our units) hotspot on the ground , say from spilt water or something else i couldn't pick up ,
AND that spot were growing grass so made an attractive place for the guys to stand while taking a breather,
THEN I would make the area around that hotspot look unattractive so they'd avoid it.
Remember the temporary workers have only brief training and may not notice that the sign says Millisv not Microsv...

so to discourage congregating in that nice grassy spot i'd place scary looking stuff around the sign.
It is considered in come circles 'macho' to ignore warning signs.
In early days stateside some construction workers actually competed to see who could accumulate the most dose.

Observe the grassy spot was attractive enough to interest a cameraman.
I think there's probably contaminated dirt under that grass and placing blue rubble around the sign was an expedient psychological ploy.

 

[MadderDoc]

First post... Thanks to everyone for these wonderful threads full of insights on Fukushima situation!

About this mysterious "highly" radioactive rubble, 12mSv probably stands for airborne radiation. The surface must be alot more radioactive. IMHO, the warning message and cone is fully justified as staying near this area would lead to significant external exposure.

Welcome to you.

You could be right. On the sign a few lines under the 12 mSv/h header another measurement - 950 mSv/h -- is written in smaller types,

 

[jlduh]

Welcome to you.

You could be right. On the sign a few lines under the 12 mSv/h header another measurement - 950 mSv/h -- is written in smaller types,

Great Madderdoc, so maybe Tepco reported the picture of the 950 mSv/h rubble I admit... for those who has good eyes at least I guess Almost 1 Sv/h could explain grass death.

Could somebody translate the full text for information?

 

[elektrownik]

Welcome to you.

You could be right. On the sign a few lines under the 12 mSv/h header another measurement - 950 mSv/h -- is written in smaller types

LOL this is strange, maybe 12 is air radiation and 950 surface ??

 

[SteveElbows]

Do you honestly think that Arny Gundersen is painting an inaccurate tapestry? If so, please paint me an accurate one, and give me links to get accurate information.

Its not our fault that Gundersen damaged his own credibility in the past. He claimed to know a thing or two about fuel pools, and then proceeded to incorrectly assume that the refuelling bridge had fallen into the pool at unit 4, and that we could see fuel racks in a video. He also used sloppy language when describing elements of nuclear fuel 'several miles' away from site.

Of course this does not mean he will always be wrong, but he has proven too quick to leap to large and serious conclusions based on not enough evidence in the past, and there is no getting away from that.

 

[SteveElbows]

yes but we can see that something changed:
data from 5/16 to 6/5 measured 2 times per day

The pattern of skimmer water level rising rapidly (when they put water into the pool and it overflows into skimmer), and then falling is not unusual, its what we would expect and have seen at other fuel pools where data is available.

What is different this time is how low the level has fallen to. There are several possibilities for this, since water can be moved from skimmer tank elsewhere under normal conditions. I suppose it is possible that something new has broken which causes the skimmer tank to empty more, but that's not a certainty, and it doesn't tell us about the state of the pool itself.

 

[StrangeBeauty]

LOL this is strange, maybe 12 is air radiation and 950 surface ??

They usually put both measurements on the survey, but there was only the single one in this case:
http://www.tepco.co.jp/en/nu/fukushima-np/f1/images/f1-sv-20110605-e.pdf
I think it is possible that is the airborne measurement. Kindly, could one of our japanese translaters take a look at text of the sign? :)

I also notice that the separate sweeps at two different times on that day were not differentiated by color as they had been on past surveys. Additionally, all the readings at the bottom of the survey are lacking airborne|surface differentiation. Perhaps the surveyor was starting to worry about his exposure and was hurrying along? That would go against the logic of taking time out for a photo shoot.

 

[jim hardy]

This may be old news , but for you who like to read dull technical reports

finally stumbled across the newer version of "Identification & Mitigation of BWR Severe Accident .."
the early one i'd been reading was only nineteen pages, it grew to 214 and got issued as NUREG/CR-5869 about 1992.

http://www.ornl.gov/info/reports/1992/3445603689514.pdf

 

[andybwell]

Its not our fault that Gundersen damaged his own credibility in the past. He claimed to know a thing or two about fuel pools, and then proceeded to incorrectly assume that the refuelling bridge had fallen into the pool at unit 4, and that we could see fuel racks in a video. He also used sloppy language when describing elements of nuclear fuel 'several miles' away from site.

Of course this does not mean he will always be wrong, but he has proven too quick to leap to large and serious conclusions based on not enough evidence in the past, and there is no getting away from that.

Where do you differ from his overall analysis and outcome?

 

[robinson]

I think it's awesome he just had car air filters sent from Japan and analyzed them. Meanwhile all of the worlds governments can't tell you what is coming out of four buildings constantly venting "something" from reactors and fuel ponds.

 

[Bioengineer01]

http://www3.nhk.or.jp/daily/english/03_31.html

1 Ci = 37,000,000,000 Bq

Fukushima (in the water there)

720,000,000,000,000,000 Bq

Unless I made a math error, that's
19,459,459 Curies currently in just the waste water there. That doesn't include the material spread out over the land, around the world, or into the ocean from leaking water.

What was the figure for Chernobyl again?

(edit)

Ah, found it.

Chernybyl released about 1,300,000 Ci of Ce-137 and 2,400,000 Ci of Ce-137

I get different numbers for Chernobyl from http://www.oecd-nea.org/rp/chernobyl/c02.html
where did you get yours from?

Ce-137 ==> ~85 PBq or ~2.3 MegaCi
I-131 ===> ~1760 PBq or ~48 MegaCi
You can get the rest from the table in the link
PBq = 10^15 Bq
GigaCi = 10^12 Ci

 

[Jorge Stolfi]

Updated my plots of Fukushima daiichi reactor parameters up to NISA release 159 (jun/04 15:30)
http://www.ic.unicamp.br/~stolfi/EXPORT/projects/fukushima/plots/cur/Main.html

I have also added some temperature data for late march taken from the TEPCO files
http://www.tepco.co.jp/nu/fukushima-np/f1/images/syusei_temp_data_1u.pdf
http://www.tepco.co.jp/nu/fukushima-np/f1/images/syusei_temp_data_2u.pdf
http://www.tepco.co.jp/nu/fukushima-np/f1/images/syusei_temp_data_3u.pdf
Unfortunately these files do not give much new data besides what i already had,
at least for that time frame. They seem to confirm that something exceptional happened to reactor #3
in the early hours of march/21, just before the black smoke event. (Thus that
black smoke does not seem to be just an ordinary chemical fire.)

Between NISA releases 158 and 159 the core presures of reactor #1 have abruptly fallen from 679 kPa and 1674 kPa to 126 kPa and 101 kPa (?), respectively:
http://www.ic.unicamp.br/~stolfi/EXPORT/projects/fukushima/plots/cur/out/plot-pres-un1-t-T-full.png
Since the other variables remained stable, it may be a transcription error (today is sunday; only a lowly trainee in the office, perhaps?), or they recalibrated the instruments and found that the previous readings were garbage.

 

[robinson]

The cesium-137 produced each year by a 1000-megawatt (electrical) nuclear power plant amounts to nearly 4 million curies.

The Chernobyl reactor contained a two-year cesium-inventory of about 8 million curies. To say it released 2,300,000,000,000 Curies is quite a claim.

 

[Jorge Stolfi]

Well, if i follow your hypothesis, it would mean that on all soil or grass surface this dust inhibitor is wery easily washed away by water which is not a good news for rainwater contamination after rainfall on the site (or they will have to respray every time after some rain...).

Somewhere I saw a close-up picture of a bit of that dust inhibitor coating. It does not penetrate much into the soil; instead it forms a soft irregular rubbery layer on top of it. Running water, such as a moderate rain, should easily lift the coating off the dirt and carry it away.

 

[etudiant]

I get different numbers for Chernobyl from http://www.oecd-nea.org/rp/chernobyl/c02.html
where did you get yours from?

Ce-137 ==> ~85 PBq or ~2.3 GigaCi
I-131 ===> ~1760 PBq or ~48 GigaCi
You can get the rest from the table in the link
PBq = 10^18 Bq
GigaCi = 10^12 Ci

Peta is 10^15, rather than 10^18, at least afaik.

 

[Bioengineer01]

You guys and gals, of course, knew this all along. Right?

"The dangers of fukushima are greater than we think."

http://us1.campaign-archive1.com/?u=...&id=68c85cc08a

Edit by Borek: large quote possibly violating owner copyright deleted.

Yes, it is like a revolver pointed to Mother Earth with only one bullet loaded, but we don't know whether it will fire or not. I hate those who did this to us. I don't like being forced to play Russian Roulette with my family and friends...

 

[Bioengineer01]

If there were dangerous materials released from the boiling and burning fuel and concrete, including explosive Hydrogen, said materials could be problematic.

Yes, but water makes it worse...

 

[elektrownik]

Between NISA releases 158 and 159 the core presures of reactor #1 have abruptly fallen from 679 kPa and 1674 kPa to 126 kPa and 101 kPa (?), respectively:
http://www.ic.unicamp.br/~stolfi/EXPORT/projects/fukushima/plots/cur/out/plot-pres-un1-t-T-full.png
Since the other variables remained stable, it may be a transcription error (today is sunday; only a lowly trainee in the office, perhaps?), or they recalibrated the instruments and found that the previous readings were garbage.

They installed new pressure measure system and discovered that old data were wrong...
http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_110602_02-e.pdf
http://www.tepco.co.jp/en/news/110311/images/110604_10.jpg

Also your plots of water level for unit 1 are worng, new sensor show that water level is "DS - Down Scale" which mean at lat -5m, not -4m

 

[Bioengineer01]

If there were dangerous materials released from the boiling and burning fuel and concrete, including explosive Hydrogen, said materials could be problematic.

Now that's exactly the point.

I propose encasing it (them) in a ten meter thick* cocoon of dry sand.
You propose pouring water on it .
Right?

Shall we continue from there?*(ten meter radius around each corium at minimum)

Agree with more sand added as the sand melts and mixes with the Corium, that worked in Chernobyl, we should not experiment here, same stuff as was mixed in Chernobyl... And, absolutely NO water...

 

[Bioengineer01]

A bit too much hyperbole for me.

He has discredited himself so that I don't listen to him.

But the other side is just as bad.

I didn't like his last statements at all... Although, he has chosen a "no win" position to be in... Very difficult to be him right now...

 

[Quim]

Yes but they are still hight radioactive, you don't want radioactive fuel rods to be exposed to air... water is not only coolant but also radiation shield

What or whom does SFP 1 need to be shielded from?

Judging from the radiation readings that have been released recently, it appears that no human will be working anywhere near that SFP for the next 150 years or so.

The rods in unit one are putting out about 2% of the heat and radiation that the #4 pond was said to be producing early on.
I can't say what would be the result of those particular rods meeting air but if it were a problem it would be easy enough to fill the pool with sand.

In post #5395 Jorge Stolfi estimated the total volume of a SFP as about 1600m³
"In that case, from the ~1690 m³ you should subtract ~95 m³ to get the free volume of the SFP."

But the fuel rods are only occupying the lower half of that space so 800 m³ of sand would be a permanent fix for that - if its a problem.
Tepco doesn't seem worried about it.


This is no longer a functioning reactor building.
It is now a gravesite.

 

[Jorge Stolfi]

They installed new pressure measure system and discovered that old data were wrong...
http://www.tepco.co.jp/en/nu/fukushima-np/images/handouts_110602_02-e.pdf
http://www.tepco.co.jp/en/news/110311/images/110604_10.jpg

Yep. Isn't it a great feeling when you find that you have been plotting and analyzing garbage data for three months?

So, to simplify the picture, all three reactors are at atmospheric pressure. So they probably have a hole at the bottom, and their fuel is lying on the concrete at the bottom of the drywell, optimistically. And their "primary containments" seem to be leaking like sieves.

(But how could a manometer measure 1.6 MPa if everything is at atmospheric pressure? Perhaps a steam leak from Fukushima Daini, traveling through a crack in the Earth's mantle?)

Also your plots of water level for unit 1 are worng, new sensor show that water level is "DS - Down Scale" which mean at lat -5m, not -4m

Thanks. I wasn't sure what exactly was the bottom of the instrument's scale and conservatively guessed -4 m.

(They could make our life a bit easier by writing "< 5000mm", "> 400 C" etc. instead of just "downscale" or "offscale"...)

 

[Astronuc]

What or whom does SFP 1 need to be shielded from?

Judging from the radiation readings that have been released recently, it appears that no human will be working anywhere near that SFP for the next 150 years or so.

The rods in unit one are putting out about 2% of the heat and radiation that the #4 pond was said to be producing early on.
I can't say what would be the result of those particular rods meeting air but if it were a problem it would be easy enough to fill the pool with sand.

In post #5395 Jorge Stolfi estimated the total volume of a SFP as about 1600m³
"In that case, from the ~1690 m³ you should subtract ~95 m³ to get the free volume of the SFP."

But the fuel rods are only occupying the lower half of that space so 800 m³ of sand would be a permanent fix for that - if its a problem.
Tepco doesn't seem worried about it.


This is no longer a functioning reactor building.
It is now a gravesite.

The SFPs must be secured in order to eventually access the reactors and cores of Units 1, 2 and 3, which must eventually happen in order to mitigate further release of fission products. As long as the reactor service floors are contaminated and cluttered with debris, it is impossible to begin removing the spent fuel. As it stands, the SFPs have direct communication with the atmosphere, and thus a direct path between released fission products and the environment.

The spent fuel must be removed from the SFPs of Units 1-4 in and placed in casks. That can only happen after the debris is removed, and most likely will have to be done remotely, and possibly robotically.

 

[elektrownik]

The bad thing is that TEPCO know that unit 1 is at atmospheric pressure science some time, why ? Because of scale of instruments which they instaled in last days. They can show 3 times atmospheric pressure only. Old data were showing 15 times atmospheric pressure, so if they would not know that unit 1 is at atmospheric pressure they should install indicator with much more bigger scale...


Finally:
-From 10:16 am to 10:48 am on June 5, we started the water
injection to the spent fuel pool of Unit 1 by a temporary motor
driven pump.
-At 1:08 pm on June 5, we started the water injection to the spent
fuel pool of Unit 3 by a temporary motor driven pump (from 1:14 pm
to 2:16 pm, we added hydrazine (antioxidant)).