Japan Earthquake: nuclear plants


by gmax137
Tags: earthquake, japan, nuclear
artax
artax is offline
#5743
May4-11, 03:24 AM
P: 159
Quote Quote by Zallia View Post
Have you all seen the live cam?

http://www.youtube.com/watch?v=Ck_KE...layer_embedded

Looks like fires breaking out in #3 and #4.
That's a nice find that is.
looks as if it's a day or two behind according to some text on the screen.... would be nice to know.
And yes it looks like it's from the same vantage point as the explosion vids.... my concern is the wind direction..... It looks on shore now.
zapperzero
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#5744
May4-11, 03:34 AM
P: 1,030
New fuel is put in the pool for safety, but also because it can only be put in the reactor one way: by being picked up from the pool, moved through a trough, underwater, between the pool and the reactor and inserted, while still underwater, in the reactor core.
jpquantin
jpquantin is offline
#5745
May4-11, 03:42 AM
P: 33
Quote Quote by ~kujala~ View Post
Sorry if this has been discussed earlier.

France's IRSN has calculated that SFP 4 would lose max 115 tons per day.


http://www.world-nuclear.org/info/fu...nt_inf129.html

How was this 71 tons calculated? And can we be absolutely sure about it?
71 tons is calculated from estimating heat generation from SFP4 to 1,600 kCal/hour / 2MW. Was estimated by Atomic Energy Society of Japan (AESJ), source if here (http://www.aesj.or.jp/en/release/cho..._01_110418.pdf).

Both are estimates ...
jpquantin
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#5746
May4-11, 03:48 AM
P: 33
Quote Quote by triumph61 View Post
At 27. Tepco said the Pool is leaking. At 28. Tepco said the Pool is NOT leaking.
Do you have links towards this leaking / then not leaking announcements?

Quote Quote by triumph61 View Post
Whats happend? Did they find the leaked? Perhaps they also restore the cooling?
Perhaps, but most probably they would have made announcements on these good news, don't you think?
jpquantin
jpquantin is offline
#5747
May4-11, 03:51 AM
P: 33
Quote Quote by SteveElbows View Post
I will probably still try to keep somewhat of an open mind about this data and what it means, just in case there is some factor we are missing, or for example if they have already tried to convert the raw skimmer water temperature into a pool temperature before publishing the data. I doubt this but its just one example of things I cannot be sure about.
We would need to know what is the exact shape of the FPC skimmer surge tank in unit 2 to check, based on its level and announced temperature. If of cylinder shape, then it seems to me it may be the deduced (calculated) temperature of the SFP.

They could also estimate temperature of SFP thanks to infrared aerial measurements, or also a thermocouple attached to the concrete truck arm.
artax
artax is offline
#5748
May4-11, 03:53 AM
P: 159
Radiation levels in unit 1 "far higher than tepco expected"

http://www.telegraph.co.uk/news/worl...ima-plant.html

I'll try to correct that link
PietKuip
PietKuip is offline
#5749
May4-11, 04:16 AM
P: 184
Quote Quote by ~kujala~ View Post
http://www.nisa.meti.go.jp/english/f...110406-1-1.pdf (page 36)
New fuel is heat negligable.
Yes, until it goes critical.

Criticality is supposed to be prevented by boron in Boral sheets. Aluminum is stable in water only when the water is at neutral pH.

So when cooling gets lost, the spent fuel is boiling off the water, fuel rods get exposed and really hot, zircalloy is reacting with water, H2 is developed, and the water becomes alkaline (I think). This eats away Boral really fast in hot water. The boral sheets drop to the bottom of the pool.

Anything that can go wrong, will go wrong. If aluminum can dissolve in water when it is alkaline or acidic, it is just bound to happen somewhere sometime. From a safety point of view, the choice of aluminum as a matrix for boron is just incredibly stupid.

But the company says: http://www.ceradyneboron.com/product...sorbers/boral/
"currently used at seventy nuclear power plants and eleven research reactors worldwide"
"It is well suited to many nuclear applications including storage of spent nuclear fuel, "
Jim Lagerfeld
Jim Lagerfeld is offline
#5750
May4-11, 04:19 AM
P: 42
Quote Quote by jpquantin View Post
Do you have links towards this leaking / then not leaking announcements?
April 27th:
TEPCO: Water may be leaking from No. 4 reactor fuel pool
http://www3.nhk.or.jp/daily/english/27_09.html

April 28th
TEPCO: Water isn't leaking from No. 4 reactor pool
http://www3.nhk.or.jp/daily/english/28_05.html
MadderDoc
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#5751
May4-11, 04:22 AM
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P: 698
Quote Quote by jim hardy View Post
<..>
i am curious about the orange flash at beginning of #3 video, and if you find the right youtube there was one in first fraction of a second of unit 1 as well. <..> Does anybody know of a frame by frame?
You can have a peek here:
http://gyldengrisgaard.dk/fuku_expl1/
http://gyldengrisgaard.dk/fuku_expl3/

(I would be happy for someone else to mirror this stuff
I do not really have the bandwidth to serve properly)

And is there anything to be gleaned from the burst of orange flame?
Orange is the color of burning salt but they weren't spraying seawater into the pools yet, as best i could find.
I don't think much can be gleaned from the color of the explosions. Hydrogen does burn ideally, like in a test tube, with an almost invisible flame, however in a real world hydrogen explosion, other stuff, e.g. dust, soot, will be present or be produced and be heated by it, producing a yellowish or reddish glow.
see:
http://www.youtube.com/watch?v=MMB2VR0087w
jpquantin
jpquantin is offline
#5752
May4-11, 04:29 AM
P: 33
The attached capture shows smoke over unit 2, 3 and 4.

I would go for steam - all same color for all units.

Also I do not see the red arm of the concrete truck near unit 4, but maybe this is too small to be visible ?
Attached Thumbnails
Unit 2-3-4 smoke May 4th 0624 PM JPT.PNG  
rowmag
rowmag is offline
#5753
May4-11, 04:31 AM
P: 209
Quote Quote by |Fred View Post
there is a hudge disparity between the document found there
http://www.mext.go.jp/a_menu/saigaij...ai/1305747.htm
and the one found there http://www.nsc.go.jp/mext_speedi/

Translation help is needed to know exactly what we are reading about
The first link only gives instantaneous simulations up to 3/16.
More recent updates are found here: http://www.nsc.go.jp/mext_speedi/past.html, which URL is found on the second link you gave above.

The second link you gave is the one I briefly explained in the post below:
http://physicsforums.com/showpost.ph...postcount=5596

I'm not up for translating the whole thing, but if there are particular plots or other bits you are curious about, I can try to explain those (if someone else doesn't first).
artax
artax is offline
#5754
May4-11, 04:35 AM
P: 159
Quote Quote by jpquantin View Post
The attached capture shows smoke over unit 2, 3 and 4.

I would go for steam - all same color for all units.

Also I do not see the red arm of the concrete truck near unit 4, but maybe this is too small to be visible ?

Yes it is certainly steam as it soon disappears... however it is probably radioactive and the wind is now on shore so it will be falling inland and I expect TEPCO's radiation readings to rise considerably.
ernal_student
ernal_student is offline
#5755
May4-11, 04:39 AM
P: 34
On that site, you may be interested in this page with daily report collections:

http://www.nsc.go.jp/mext_speedi/past.html

Each collection has hourly reports, each showing a wind direction map and a plume flow map
~kujala~
~kujala~ is offline
#5756
May4-11, 04:45 AM
P: 110
Quote Quote by jpquantin View Post
71 tons is calculated from estimating heat generation from SFP4 to 1,600 kCal/hour / 2MW. Was estimated by Atomic Energy Society of Japan (AESJ), source if here (http://www.aesj.or.jp/en/release/cho..._01_110418.pdf).

Both are estimates ...
Thank you, now I have seen at least three different estimates, MIT estimate is conservative, AESJ seems to be quite optimistic, IRSN is somewhere between.

Is there any reasons to believe that some of these estimates could be questioned?
Borek
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#5757
May4-11, 05:05 AM
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P: 22,655
Quote Quote by artax View Post
the wind is now on shore so it will be falling inland
Can be, but doesn't have to. Please remember there is an elevated terrain just behind the plant. It can be a horizontal whirl just on the shore, the air higher can be going in the direction of the sea, and sucking air from the sea over the buildings.
jpquantin
jpquantin is offline
#5758
May4-11, 05:05 AM
P: 33
Quote Quote by Jim Lagerfeld View Post
April 27th:
TEPCO: Water may be leaking from No. 4 reactor fuel pool
http://www3.nhk.or.jp/daily/english/27_09.html

April 28th
TEPCO: Water isn't leaking from No. 4 reactor pool
http://www3.nhk.or.jp/daily/english/28_05.html

Thanks !

From first link:

TEPCO has poured in 140 to 210 tons of water over each of the last few days. The company found that water levels in the pool were 10 to 40 centimeters lower than expected despite the water injections.
Means they monitor water level at SFP4, but does not tell us when and how. Also 10 cm of water in SFP4 is 12 tons, 40 cm is 48 tons (if pool gate still there, more if not). Without knowing the time of measurement, no conclusion is possible. Would be soon after injection, I guess ...

From second link:

But the company said on Wednesday that it now believes that the water has been evaporating at a rate in line with calculations by experts.
We come back to the boiling rate. I'd really love to have these experts calculations. Until now ...

If we take IRSN figure, we cannot tell for sure the SFP is leaking. The latest average loss is close to this figure (114 compared to my 124).

If we take AESJ figure, there MUST be leaks to explain the losses, because the boiling rate (70) is far below the average rate of loss (my 124).

Unless I'm incorrect, or data are corrupted, or calculation false, or FPC skimmer level not working correctly, or ... (etc).

Also what is surprising is that during video snapshot of Apr 28 I could not see evidence of a completely boiling pool. But this was just after the latest "full" signal, pool had just been refilled. And I must admit that I have not see many boiling SFP in my life ...

Any data on boiling rate estimates, based on number and "age" of rods in SFP4, would be appreciated ...
jlduh
jlduh is offline
#5759
May4-11, 05:26 AM
P: 468
Quote Quote by jlduh View Post
Did somebody knew that tepco seem to have vented through the stack on this timelapse video at a moment indicated as the 13th of March at around 14h00 (see at t=around 0:30' on this video)

http://www.youtube.com/watch?v=JAYGclBAym8

There may be (but I'm not sure) an other small venting at t=0:29' (13th of March at 10h00) and previously one at t=0:24' which is indicated as the 12th of March at 15h00.

I believed that there was no possibility to vent directly to the outside through the stack because this had to be actuated through a valved requiring electricity and there was total blackout at the plant at this date after the tsunami?

That's the reason that was presented by some on this forum to explain why they were venting manually inside the buildings, leading to the H2 explosions.

Any explanation?
I quote myself because i didn't get any comments on this right now and i find this confusing based on what was considered until now...

If venting through stack could be operated (i don't see very well on the frames which stacks are the plumes coming from: i think the N3/N4 stack for the plume the 13th March at 14h00, right?), why did they changed to Inside buildings venting with H2 risks of explosion if it was NOT because there was no other option because black out?
zapperzero
zapperzero is offline
#5760
May4-11, 05:29 AM
P: 1,030
Quote Quote by jlduh View Post
Why did they changed to Inside buildings venting with H2 risks of explosion if it was NOT because there was no other option because black out?
There is no way to intentionally vent inside. Hydrogen escaped into the building, then went boom.


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