Japan Earthquake: nuclear plants


by gmax137
Tags: earthquake, japan, nuclear
LabratSR
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#14185
Sep17-13, 07:09 AM
P: 173
Thanks, here is the TEPCO release about Unit 1

http://www.tepco.co.jp/en/nu/fukushi...30509_07-e.pdf
Rive
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#14186
Sep17-13, 01:52 PM
P: 337
Some video tour?

http://photo.tepco.co.jp/en/date/201...30917-03e.html

Ps.: it's almost useless. The only new information I could spot was that the remaining concrete beams on U3 top are now removed.
SteveElbows
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#14187
Sep17-13, 04:16 PM
P: 630
Quote Quote by LabratSR View Post
Another update from TEPCO and yet again, absolutely nothing covered other than the water issues. Status of the clean-up of the units? Fuel removal from Unit 4 SFP? Removal of the Unit 1 cover? Location of the cores? And on and on.

Thanks for posting.
Others have pointed out documents that give some clue as to timescales for some of these tasks, though I'd have to go back over a mess of documents to fill in some of the remaining gaps. I'll return to some in the coming hours or days but for now I will just deal with core location surveys.

Reactor 3 needs more decontamination inside the reactor building before they do any useful surveys. We hear very little about reactor 1. Reactor 2 is where there has been the most progress, including in recent months.

The last thing we learnt about reactor 2 is not many pages ago on this thread, with the last survey revealing a rate of 36 Sv/h just outside the pedestal opening. But now they have to look at the results & tricky operating conditions encountered during that survey in order to plan the next survey which will hopefully go inside the pedestal area and give a better idea about core location.

One other thing I may have learnt from that survey, if all the documents & diagrams were accurate, is that the location of the full 'door' into the pedestal area, is to the south-east. This is based on an assumption that this door, which was of interest to those wondering about molten core flow or splashing outside of the pedestal area, is opposite the pedestal opening that they got close to in this survey (this surveyed opening is more like a window than a door, and is used to replace control rod drivers).

Anyway, when trying to guesstimate core location at this stage, apart from that 36 Sv/h figure for reactor 2, and the various theoretical analysis done with models, I think the only other thing we have to go on is the state of the torus rooms at the three reactors. It is tempting to suggest that radiation dose levels in the torus rooms of reactors 2 & 3 are not spectacular enough to promote theories about core migrating away from the drywell containment in these reactors. But the very limited surveying possible at reactor 1 torus room, along with the levels of radiation measured there, may hint at a more interesting story for that reactors core. But I expect it would be grossly premature to make any conclusions based on this, its just what I'm throwing out there during the long wait for more substantial data. Thoughts more than welcome, including whether the 36 Sv/h reading near the pedestal opening of reactor 2 is the sort of reading we might expect if most of the core was either in the bottom of the RPV or the pedestal area of this reactor.
SteveElbows
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#14188
Sep17-13, 04:29 PM
P: 630
Filling in more questions about timing, this time in relation to fuel removal from reactor 4 pool.

I think the last we heard about this was a pool & reactor debris survey from August:

http://www.tepco.co.jp/en/nu/fukushi...30809_07-e.pdf

According to that the debris removal work should have started in late August, and I expect that if they don't get stuck, we will hear about the next phase before the end of this year.

edited to add that schedule can be seen in this document from later in August, after they formed a plan based on the debris survey I just mentioned:

http://www.tepco.co.jp/en/nu/fukushi...30826_07-e.pdf

Fuel removal currently scheduled to start mid-november according to that.
etudiant
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#14189
Sep17-13, 05:30 PM
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Quote Quote by Rive View Post
Well... Once they will be able to remove Sr (and some other elements) they should dump that water somewhere. Even if I prefer places where it'll be isolated for some time (this includes some natural reservoirs deep below), it would do practically nothing even if they mix it well in the ocean.

Logic would suggest park it in a tanker, freeze it and send it to someplace really cold. It should not be too hard to keep it as an ice cube for a century or two somewhere in a polar region.
After that it should not matter if the tanker rusts out beneath the cargo.
jim hardy
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#14190
Sep17-13, 06:12 PM
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I'd suggested a line of old Liberty Ship boilers to distill it. Demineralizers are wonderful but you are left with a LOT of contaminated resin. And seawater wrecks demineralizer resins quickly.
Boiler sludge would be more compact i'd think.
jim hardy
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#14191
Sep17-13, 06:12 PM
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oops double post - how'd that happen?

removed
Rive
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#14192
Sep18-13, 02:29 AM
P: 337
Quote Quote by nikkkom View Post
I guess there isn't significant difference in concentration of D compared to natural water.
As it seems, you are right:
http://www.nap.edu/openbook.php?record_id=9263&page=113
So it cannot be used as a raw material for the heavy water industry.

Quote Quote by etudiant View Post
Logic would suggest park it in a tanker, freeze it and send it to someplace really cold. It should not be too hard to keep it as an ice cube for a century or two somewhere in a polar region.
After that it should not matter if the tanker rusts out beneath the cargo.
My idea is to pump it down to some geologic formation where the water moves only slowly.
But the 'rust in peace' is also good. It has to be 'out of the way' only for a hundred year or so.
a.ua.
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#14193
Sep18-13, 05:09 AM
P: 119
Quote Quote by LabratSR View Post
Removal of the Unit 1 cover?

Thanks for posting.
Perhaps, if you look through the periscope of this will be seen something.
http://photo.tepco.co.jp/date/2013/2...30918-01j.html
tsutsuji
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#14194
Sep19-13, 05:40 AM
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http://www3.nhk.or.jp/news/genpatsu-...918/index.html Damages such as cracks were found in 8 locations at elevation 66 m on the unit 1/ unit 2 stack (full height, about 120 m). The cracks are thought to have been caused by the March 2011 earthquake. Tepco will check the resulting earthquake resistance against future earthquakes. The stack is presently unused. As the radiation in the stack vicinity is as high as 10 Sv/hour Tepco is studying how to perform a detailed survey.

http://www.tepco.co.jp/nu/fukushima-...30918_13-j.pdf Japanese language handout with picture.
LabratSR
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#14195
Sep19-13, 01:58 PM
P: 173
Thanks to everyone for the updates.


I found this on the TEPCO site, dated July 25th

Progress Status and Future Challenges of the Mid-and-long-Term Roadmap toward the Decommissioning of Units 1-4

http://www.tepco.co.jp/en/nu/fukushi...30725_01-e.pdf



I also found this on the NRA site.

Updated Status of Fukushima Daiichi Nuclear Power Station - Sept. 16

http://www.nsr.go.jp/english/data/20...esentation.pdf
StrangeBeauty
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#14196
Sep19-13, 02:10 PM
P: 61
Quote Quote by tsutsuji View Post
<snip>Tepco will check the resulting earthquake resistance against future earthquakes. <snip>
It appears Tepco went with live testing today!
http://earthquake.usgs.gov/earthquak...0jw8u#shakemap

Seriously, probably not much of an issue...

Thanks to everyone for continuing to track this evolving disaster, especially tsutsuji and others that do translations and reading between the lines.
LabratSR
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#14197
Sep19-13, 06:58 PM
P: 173
New method reduces analysis time of radioactive strontium

http://ajw.asahi.com/article/0311dis...AJ201309190058
a.ua.
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#14198
Sep20-13, 02:31 AM
P: 119
LabratSR
New method reduces analysis time of radioactive strontium

Although the conventional technique has superior analytical sensitivity, with only a minimal amount of components needed to be reliably detected in sample, the process took from two to four weeks
http://ajw.asahi.com/article/0311dis...AJ201309190058
has long existed in the "iron" and running in 30 minutes qualifies.

http://akp.com.ua/en/index.php?optio...ren&Itemid=106
Greg Bernhardt
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#14199
Sep20-13, 02:33 PM
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Please continue discussion in Part 2
http://www.physicsforums.com/showthread.php?t=711577


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