Japan Earthquake: nuclear plants

tsutsuji

http://www.tepco.co.jp/nu/fukushima-...ference-j.html The 13th mid-long term meeting was held on 25 December 2012 [but the pdf presentations are not available at http://www.meti.go.jp/earthquake/nuc...issioning.html yet]

http://www.tepco.co.jp/nu/fukushima-...21225_05-j.pdf There is something new about the plan to use the TIP guide tubes for installing alternative thermometers in unit 2. Some work for this was started on 20 December. There is a plan to inject nitrogen into unit 2 suppression chamber like they did at unit 1. There is a High Integrity Container (HIC) falling test. There is some more about the plan to close unit 2's blowout panel. There is something on unit 3's debris removal work.

zapperzero

http://www.japantimes.co.jp/text/nn20130101a3.html

It would be really nice if some US citizen could do a FOIA request for those flight records and the test data... I am pretty sure that there are/were reporters lurking in this thread. Perhaps we would then learn more about the timing of radioactive releases.

Azby

I'm not a reporter, but I've looked at the NNSA data available here:

http://www.nnsaresponsedata.net/

There's a lot there, maybe what you're looking for. It requires a registration, but that took only about 2 hour to turn around.

zapperzero

http://www.tepco.co.jp/en/news/libra...d=400972619002

Joffan

Why on earth did Tepco post that - it shows absolutely nothing.

The other videos on that page are interesting though.

Astronuc

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

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

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

no, it is not. that's a much older video

turi

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

Okay. I stand corrected. Thanks for the further link.

LabratSR

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

The conclusions are highly suspect, imho. How can anyone say that a model is accurate when the actual sequence of events remains unknown?

NUCENG

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

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.
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

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

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.