Japan Earthquake: Nuclear Plants at Fukushima Daiichi

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Discussion Overview

The discussion revolves around the technical aspects and current status of the nuclear plants at Fukushima Daiichi following the earthquake and tsunami in Japan. Participants are seeking reliable information regarding the operational conditions, safety measures, and potential risks associated with the nuclear reactors in the aftermath of the disaster.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants express skepticism about the reliability of media reports and emphasize the need for technical information from official sources like TEPCO and METI.
  • There are concerns regarding the reactor pressure levels, with reports suggesting that pressure may have exceeded safe limits, which some participants describe as a significant issue.
  • Questions are raised about the likelihood of a meltdown, with differing opinions on whether this is a realistic concern or media exaggeration.
  • One participant explains the role of coolant in a nuclear power plant, noting that it is essential for cooling the reactor and managing decay heat after shutdown.
  • There is discussion about the reactor's ability to be scrammed (shut down) and the implications of losing coolant, with some participants clarifying that decay heat continues to be produced even after shutdown.
  • Concerns are raised about the explosion of the containment building and its implications for safety, with speculation about the potential release of radioactive materials.
  • Participants discuss the wind direction at the time of the explosion and its potential impact on the dispersion of any radioactive materials released.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the likelihood of a meltdown or the implications of the current situation at Fukushima Daiichi. There are multiple competing views regarding the severity of the situation and the reliability of information being reported.

Contextual Notes

Participants note the limitations of available information, including the reliance on second-hand reports and the challenges in verifying the status of the reactors and containment structures. There are also unresolved questions regarding the operational status of safety systems and the exact nature of the explosion.

  • #8,881
andybwell said:
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.
 
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  • #8,882
elektrownik said:
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.
 
  • #8,883
elektrownik said:
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.
 
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  • #8,884
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
 
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  • #8,885
SteveElbows said:
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?
 
  • #8,886
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.
 
  • #8,887
robinson said:
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
 
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  • #8,888
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.
 
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  • #8,889
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.
 
  • #8,890
jlduh said:
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.
 
  • #8,891
Bioengineer01 said:
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.
 
  • #8,892
andybwell said:
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...
 
  • #8,893
swl said:
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...
 
  • #8,894
Jorge Stolfi said:
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
 
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  • #8,895
swl said:
If there were dangerous materials released from the boiling and burning fuel and concrete, including explosive Hydrogen, said materials could be problematic.

Quim said:
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...
 
  • #8,896
Quim said:
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...
 
  • #8,897
elektrownik said:
Yes but they are still height 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.
 
  • #8,898
elektrownik said:
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?)

elektrownik said:
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"...)
 
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  • #8,899
Quim said:
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.
 
  • #8,900
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)).
 
  • #8,901
Quim said:
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.
[...]
The rods would melt and release various volatile radioactive isotopes into the air. Why would you want that? Just so you don't have to care about the SFP 1 anymore?
 
  • #8,902
elektrownik said:
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.

Japanese version of status updates said that they injected just 15t. This is very small amount compared to what goes into reactor 4 pool, and is further indication that unit 1 pool is not a major concern at this time.
 
  • #8,903
Bioengineer01 said:
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...

I hope you don't mind, but I sent you a PM
 
  • #8,904
jlduh said:
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! :eek:) 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...

Hahahahaha...Very good one
 
  • #8,905
Astronuc said:
eventually access the reactors and cores of Units 1, 2 and 3


Possibly you industry guys need to pause and take a deep breath. Nobody is going to "access the reactors and cores of Units 1, 2 and 3" in the lifetime of you or your grandchildren.

There are no more "reactors" or "cores" in units 1,2 or 3.
There are blobs of corium which hopefully, but not necessarily, live mostly in what is left of the primary containment vessels. These blobs should not be dug up in any way.
 
  • #8,906
Borek said:
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.

Sorry Mentor, you probably know a lot more physics than me, but I did work in a F50 Corporation, they have FULL departments of people that all they do all day long is to discuss details of how to arrange pictures like this to achieve the communications goal that they have. Nothing they report is random, unless you can get your hands on raw data that sometimes leaks out form a whistle blower that doesn't want to be identified. A 6 billion top line corp. in the USA may have 100+ people working on communications...
 
  • #8,907
andybwell said:
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.

Andy, you can get a much better picture of the consequences of radiation from Dr. Helen Caldicott, here is her web site: http://www.helencaldicott.com/ she was a high income high prestige MD, that delved into the effects of radiation on health and decided to make it her life goal to fight those who were spreading lies and creating cover ups. I call her the Mother Theresa of radiation protection. Of course the Nuclear industry calls her nuts. But never ever dears to engage her on a serious scientific discussion on the matter.
 
  • #8,908
http://www3.nhk.or.jp/daily/english/05_21.html"
 
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  • #8,909
turi said:
The rods would melt and release various volatile radioactive isotopes into the air. Why would you want that? Just so you don't have to care about the SFP 1 anymore?

I don't agree with your scenario.
 
  • #8,910
Quim said:
Possibly you industry guys need to pause and take a deep breath. Nobody is going to "access the reactors and cores of Units 1, 2 and 3" in the lifetime of you or your grandchildren.

There are no more "reactors" or "cores" in units 1,2 or 3.
There are blobs of corium which hopefully, but not necessarily, live mostly in what is left of the primary containment vessels. These blobs should not be dug up in any way.

Cleanup for the 50%? melted core at TMI took 5 years..
http://www.threemileisland.org/downloads//226.pdf

I have a feeling it won't take generations and generations to cleanup the majority of this mess. but the site will never be 100% again.
 

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