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Japan Earthquake: nuclear plants

by gmax137
Tags: earthquake, japan, nuclear
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zapperzero
#13825
Feb10-13, 11:37 AM
P: 1,044
http://www.tepco.co.jp/en/news/libra...d=400972619002
Joffan
#13826
Feb10-13, 03:21 PM
P: 361
Why on earth did Tepco post that - it shows absolutely nothing.

The other videos on that page are interesting though.
Astronuc
#13827
Feb10-13, 03:27 PM
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P: 21,869
I didn't see much of interest in the video, since the water is rather murky.

Better images are available here - http://www.world-nuclear-news.org/RS...l_0302131.html
zapperzero
#13828
Feb11-13, 03:58 AM
P: 1,044
Quote Quote by Astronuc View Post
Better images are available
Actually I was trying to post a video of a Unit 1 walkthrough... dunno what happened to the link.
EDIT: third one down on the right side, same page. Can't be bothered to figure how to link directly to it... I'll put it on Mega or something later.

LATER EDIT:
here it is
turi
#13829
Feb16-13, 01:35 PM
P: 46
That's the tepco link you were looking for:
http://photo.tepco.co.jp/en/date/201...30207-01e.html

Quite intriguing video from October 18, 2011. Quite a bit of noise. My limited Japanese knowledge picked up things like "xyz milli" presumably being the current mSv/h (or possibly the accumulated dose in mSv, I didn't pay enough attention to the numbers), readings from sensors ("kochira zero desu": "This one is zero"), things like "daijoubu desu ne" (good, ain't it) and "ikimashou, ikimashou" (let's go, let's go) when the radiation alert goes off (I think it goes off because they have reached a preliminarily set maximum accumulated dose as it goes of at a place where they have been before).

Can anyone with more knowledge of Japanese and the daichi reactors shed some light on what they were inspecting up there in unit 1?
zapperzero
#13830
Feb16-13, 02:05 PM
P: 1,044
Quote Quote by turi View Post
That's the tepco link you were looking for:
no, it is not. that's a much older video
turi
#13831
Feb16-13, 02:17 PM
P: 46
no, it is not. that's a much older video
Hm, it the same as the one you've uploaded to mega and has been released on February 6 this year.

There's now also a video been released yesterday from the same place but recorded in November 2012. Much better video quality. They even look at some of the same instruments.
http://photo.tepco.co.jp/en/date/201...30215-01e.html
zapperzero
#13832
Feb18-13, 05:29 AM
P: 1,044
Quote Quote by turi View Post
Hm, it the same as the one you've uploaded to mega and has been released on February 6 this year.
Okay. I stand corrected. Thanks for the further link.
LabratSR
#13833
Feb21-13, 07:54 PM
P: 177
Will Davis over at Atomic Power Review has updated his site to include a section on the Fukushima accident.

http://atomicpowerreview.blogspot.co...t-reports.html



One report that caught my eye was the one from Sandia National Labs, which I don't remember seeing before. Apologies if it has been posted here previously.

http://energy.sandia.gov/wp/wp-conte...D2012-6173.pdf
zapperzero
#13834
Feb25-13, 08:17 AM
P: 1,044
Quote Quote by LabratSR View Post
Will Davis over at Atomic Power Review has updated his site to include a section on the Fukushima accident.

http://atomicpowerreview.blogspot.co...t-reports.html



One report that caught my eye was the one from Sandia National Labs, which I don't remember seeing before. Apologies if it has been posted here previously.

http://energy.sandia.gov/wp/wp-conte...D2012-6173.pdf
The conclusions are highly suspect, imho. How can anyone say that a model is accurate when the actual sequence of events remains unknown?
NUCENG
#13835
Feb25-13, 01:08 PM
Sci Advisor
P: 916
Quote Quote by zapperzero View Post
The conclusions are highly suspect, imho. How can anyone say that a model is accurate when the actual sequence of events remains unknown?
If you read the Abstract of the Sandia report you will find that the model was developed to validate the MELCOR code and its ability to investigate a severe reactor accident. The results were not presented as a final analysis or truth of what actually happened. As you point out there are many things we don't know about the exact timeline, but the process of scientific inquiry does not require us to know everything to at least try to begin learning what happened. If we knew everything already we wouldn't need to model the accidents.

The models tell us what might have happened. Data from the model can be used to focus investigation where the results don't match the reality. It can be used to at least estimate the conditions to be encountered during cleanup. If they find new data the models can be updated and help refine the story. This will be ongoing for years.

Maybe this will help. The Wright Brothers built an airplane with rudimentary scientific inputs. Today's Aeronautical Engineers have far superior knowledge of why airplanes can fly. And the old story is that all that scientific modelling tells us that a bumblebee shouldn't be able to fly. Luckily, bumblebees can't read.
zapperzero
#13836
Feb25-13, 03:08 PM
P: 1,044
Quote Quote by NUCENG View Post
If you read the Abstract of the Sandia report you will find that the model was developed to validate the MELCOR code and its ability to investigate a severe reactor accident. The results were not presented as a final analysis or truth of what actually happened. As you point out there are many things we don't know about the exact timeline, but the process of scientific inquiry does not require us to know everything to at least try to begin learning what happened. If we knew everything already we wouldn't need to model the accidents.
The paper goes on to conclude that MELCOR is one hell of a code and the model as built is an excellent model, because after tweaking the input data some of the simulation results start to resemble plant readings. This is not very good science, I think.
Overall, these results increase confidence in the MELCOR code; establish confidence in the
Fukushima reactor models and spent fuel pool model; and demonstrate that the code and models
are valid for their intended use. They also add more evidence to the existing body of results that,
when taken has a whole, build confidence in the validity of the MELCOR code.
Also, I think we'd still need to model the accidents; I believe that the most important use of models is not forensic, but predictive.

In other, unrelated news the word "radiolysis" is conspicuously absent from this document...
turi
#13837
Feb25-13, 03:32 PM
P: 46
Quote Quote by zapperzero View Post
In other, unrelated news the word "radiolysis" is conspicuously absent from this document...
Do you have any indication that radiolysis would be a significant source of hydrogen compared to zirconium, steel and B4C steam oxidation? Those three sources are modeled in the analysis.
zapperzero
#13838
Feb26-13, 03:41 AM
P: 1,044
Quote Quote by turi View Post
Do you have any indication that radiolysis would be a significant source of hydrogen compared to zirconium, steel and B4C steam oxidation? Those three sources are modeled in the analysis.
Where did the hydrogen in Unit 4 come from? We're told it went into the unit 3 SGTS from the torus room, then instead of going up the stack it traveled through the vent pipe into unit 4, where it exploded... 19 hours after Unit 3 itself went up.

I have provided elsewhere here citations of research into steam radiolysis. Apparently it is much more efficient than water radiolysis. My idea, and it is nothing more than an idea as I obviously can't run experiments of any kind and I don't even have access to the relevant simulation codes, is that localized bubbling on the surface of fuel elements in the spent fuel pool (where water was no longer circulated by pump, only by convection) might have created the conditions for the production of a sufficient amount of hydrogen.
LabratSR
#13839
Feb26-13, 04:21 PM
P: 177
From Atomic Power Review.

Major New Report released by TEPCO.

http://www-pub.iaea.org/iaeameetings...n/Suzuki_d.pdf
zapperzero
#13840
Feb27-13, 03:11 AM
P: 1,044
Quote Quote by LabratSR View Post
From Atomic Power Review.

Major New Report released by TEPCO.

http://www-pub.iaea.org/iaeameetings...n/Suzuki_d.pdf
Took a quick look. The bit about shortening the cooling loops is rather interesting, as is the fact that currently the cooling water is only being scrubbed of cesium.

I kinda stared a little at the picture of workers in street clothes... apparently air dose rates at site boundary (as measured by shielded detectors in decontaminated locations) are a good indicator of the overall contamination level of the site.
VCortex
#13841
Feb27-13, 06:39 PM
P: 23
Quote Quote by LabratSR View Post
From Atomic Power Review.

Major New Report released by TEPCO.

http://www-pub.iaea.org/iaeameetings...n/Suzuki_d.pdf
I hope structural integrity and water tightness are not an issue, as it seems the grand plan involves filling everything up to the brim with water.
a.ua.
#13842
Feb28-13, 03:21 PM
P: 119
Quote Quote by zapperzero View Post

I have provided elsewhere here citations of research into steam radiolysis. Apparently it is much more efficient than water radiolysis. .
But then it would be hydrogen only on the 5th floor.
However, the explosion was also on 4 and 3 floors.


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