Japan Earthquake: nuclear plants


by gmax137
Tags: earthquake, japan, nuclear
tsutsuji
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#12799
Apr2-12, 04:32 AM
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http://www.tepco.co.jp/cc/press/betu...20402j0101.pdf Report to NISA on units 1 ~ 3 thermometer reliability. (the NISA requested Tepco to write a report once a month) : some of the thermometers not previously evaluated were found to be usable, and some were found to be broken. Some thermometers that were not connected to a digital recorder have been connnected to a digital recorder.

According to the plot on page 126, unit 2's 69 TE-16-114L#2 RPV BELLOWS SEAL AREA, newly connected to a digital recorder (on 8 March 2012) reached 100C on 19 March 2012. (but it is not marked as "broken"). TE-16-114L#1 is having a similar rising trend, reaching 83C on 19 March 2012. I will be curious to see if those two are marked "broken" in next month's report.
tsutsuji
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#12800
Apr3-12, 05:07 AM
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http://www3.nhk.or.jp/news/html/2012...177241000.html Because strong winds of 18 metres [per second] are expected, outdoor work with cranes is suspended at Fukushima Daiichi on 3 April afternoon. Crane arms have been made shorter. Sheets covering debris have been reinforced with weights and ropes.
biggerten
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#12801
Apr3-12, 06:55 PM
P: 19
Quote Quote by tsutsuji View Post
http://www3.nhk.or.jp/news/html/2012...177241000.html Because strong winds of 18 metres [per second] are expected, outdoor work with cranes is suspended at Fukushima Daiichi on 3 April afternoon. Crane arms have been made shorter. Sheets covering debris have been reinforced with weights and ropes.
About 40mph, for those of us counting on our fingers and toes.
tsutsuji
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#12802
Apr3-12, 07:03 PM
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http://sankei.jp.msn.com/region/news...0560003-n1.htm Unit 1's cover is designed to withstand winds up to 25 m/s. According to Tepco, in the case of winds stronger than the limit for unit 1's cover, the cover could be totally displaced by the wind and hit the building, but it was designed so that the load would be distributed and the building would not collapse or be damaged.
clancy688
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#12803
Apr3-12, 07:42 PM
P: 546
Isn't that only Beaufort 10?

What's with the occasional typhoon? According to wikipedia, a typhoon's a storm with wind speeds of at least 118 km/h+ - which's 33.8 m/s. Everything below is a "severe tropical storm" or less. So even the weakest typhoon would already overstrain the construction by 35%.

Isn't Japan a country which's being hit by typhoons fairly often? Wasn't there a typhoon hitting Fukushima last year? So how big are the chances for the construction of being exposed to wind speeds it wasn't designed for?
zapperzero
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#12804
Apr4-12, 01:09 AM
P: 1,030
Quote Quote by clancy688 View Post
So how big are the chances for the construction of being exposed to wind speeds it wasn't designed for?

I can't seem to find open-source analysis. Here's an extended abstract of some research paper:
http://ams.confex.com/ams/pdfpapers/137995.pdf
MadderDoc
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#12805
Apr4-12, 06:51 AM
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Everywhere I read says the complete inventory of noble gases was released from the reactors in the early phase of the accident.

But if so, why does Kr-85 still linger in unit 2?
Recent measurements at inlet of Unit 2 PCV Gas Control System:
28 March 2012 : 73 Bq/cm3
03 April 2012: 97 Bq/cm3

http://www.tepco.co.jp/en/nu/fukushi...20404_01-e.pdf
http://www.tepco.co.jp/en/nu/fukushi...20329_01-e.pdf

Could it be an effect of continuing fuel damage?
zapperzero
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#12806
Apr4-12, 07:24 AM
P: 1,030
Quote Quote by MadderDoc View Post
Could it be an effect of continuing fuel damage?
Well, some small proportion of the fuel fissions spontaneously, no? Same story as with the earlier detection of Iodine and Xenon.
tsutsuji
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#12807
Apr5-12, 05:22 AM
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http://www3.nhk.or.jp/news/genpatsu-...450_12ton.html At 1:50 AM on 5 April it was found that water was leaking from a pipe connected to the tanks where the water is stored after removing cesium. The leak stopped at 02:20 AM after closing a valve. It is thought that much of the 12 tons of water that leaked and include high concentrated strontium, have flowed to the sea. Tepco is investigating why the pipe junction failed and the quantity that flowed to the sea.

http://www.tepco.co.jp/nu/fukushima-...20405_03-j.pdf diagram, pictures about this leak
Yamanote
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#12808
Apr8-12, 04:09 PM
P: 68
Is there any detailed listing of all the radionuclides and their concentrations in the water from the reactor buildings available? I haven't seen one yet.
MadderDoc
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#12809
Apr9-12, 10:50 AM
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A comparison of survey photos of the top of fuel racks in the spent fuel pool of unit 4, with the IAEA's map of assembly decay heat activities in the pool strongly suggests that the precipitation that has formed on top of the tie plates has been shaped by the magnitude of the decay heat of each individual assembly. On top of low activity assemblies, a uniform layer appears to have developed, with only few perforations over the water tubes. On higher activity assemblies a similar layer appears to have formed, but it tends to have been cracked up and/or blown away. Here illustrated with the comparison for rack no. 22:


A similar photo mount for rack no 09, and the original IAEA activity map of the racks are attached (as shown in this map, the racks are numbered from 00 upwards, proceeding from the lower left to the upper right).
Attached Thumbnails
sfp4_rack09.jpg   unit4_sfp_map.gif  
Cire
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#12810
Apr9-12, 03:41 PM
P: 64
Quote Quote by MadderDoc View Post
A comparison of survey photos of the top of fuel racks in the spent fuel pool of unit 4, with the IAEA's map of assembly decay heat activities in the pool strongly suggests that the precipitation that has formed on top of the tie plates has been shaped by the magnitude of the decay heat of each individual assembly. On top of low activity assemblies, a uniform layer appears to have developed, with only few perforations over the water tubes. On higher activity assemblies a similar layer appears to have formed, but it tends to have been cracked up and/or blown away. Here illustrated with the comparison for rack no. 22:


A similar photo mount for rack no 09, and the original IAEA activity map of the racks are attached (as shown in this map, the racks are numbered from 00 upwards, proceeding from the lower left to the upper right).
This make sense. Hotter assemblies have induced thermals that carry away the lighter silt that has settled on them.
MadderDoc
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#12811
Apr10-12, 12:05 AM
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Quote Quote by Cire View Post
This make sense. Hotter assemblies have induced thermals that carry away the lighter silt that has settled on them.
Yeah. While on the colder assemblies those thermals were weaker, so a layer of silt could well settle on them. Under the hypothesis that what we see is the sole result of preferential sedimentation on colder parts , we would predict the rack frames and the number tags on the racks to be all covered by silt, wouldn't we?
tsutsuji
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#12812
Apr10-12, 02:46 AM
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Quote Quote by MadderDoc View Post
A comparison of survey photos of the top of fuel racks in the spent fuel pool of unit 4, with the IAEA's map of assembly decay heat activities in the pool
Hello,

Would you be so kind as to provide links to the source documents where you found the photos and the "IAEA map of assembly" ?
MadderDoc
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#12813
Apr10-12, 04:31 AM
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Quote Quote by tsutsuji View Post
Hello,

Would you be so kind as to provide links to the source documents where you found the photos and the "IAEA map of assembly" ?
The photos are cropped frames from the Tepco survey video at

http://tepco.webcdn.stream.ne.jp/www...120322_01j.zip

The map of assembly activities is cropped from the document "DOE Response to Fukushima Dai-ichi Accident"

which is included in these transcripts from the US DOE ACRS subcommittee on Fukushima May 26 2011 meeting (the map is on page 188 of those transcripts)
http://pbadupws.nrc.gov/docs/ML1114/ML11147A075.pdf

It must have been just my inference from recollection, that DOE had got the information on the Unit 4 SFP heat generation distribution via the IAEA, and I may be totally wrong, sorry. The document itself says nothing about how the data has been sourced. The original source for such detail of information must of course have been Tepco.
tsutsuji
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#12814
Apr10-12, 07:15 PM
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Thanks. I had guessed the pictures were from Tepco's videos, but I was not aware about that DOE document.
MadderDoc
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#12815
Apr13-12, 07:44 AM
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New and quite exciting photos from the spent fuel pool of unit 3
http://photo.tepco.co.jp/en/date/201...20413-01e.html
Pictures are taken close to the cask transfer area, they show upright standing fuel racks, and ..
a fine close up view of an end piece from the rail foot of the bridge that carried the fuel handling machine.

(Here seen compared to a Quince photo of the foot of the quite similar FHM bridge of unit 2
SpunkyMonkey
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#12816
Apr13-12, 08:34 AM
P: 63
Quote Quote by MadderDoc View Post
New and quite exciting photos from the spent fuel pool of unit 3...
Lol. I just came to post a link to that Tepco release. Great identity spot Maddder! More of you're non-stop top-notch analysis!

I seem to recall just a few weeks ago someone here called that the refueling crane simply fell into the pool (it wasn't blown to kingdom come) based on clues in a photo, but that least-extraordinary thesis was not too well received.

Here's a video clip of what clearly appears to be part of the refueling crane, I suspect it's the upper deck of the trolley. It's also the same object I posted previously, suggesting it looks like the trolley deck.

Here's a video expressing skepticism that the Unit-3 fuel pool exploded, which imo is further supported by the release of photos of fuel racks in SFP3. I think the Unit-3 explosion had nothing to do with the fuel pool, and the pool only suffered from in-falling debris.


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