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Japan Earthquake: nuclear plants

by gmax137
Tags: earthquake, japan, nuclear
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Jorge Stolfi
#2809
Apr4-11, 11:37 AM
P: 279
Quote Quote by Giordano View Post
Very useful plots but data don't seem updated since Apr 02. And I think latest release from NISA is 70 (at least in English).
It shoud be updated now to release 72. Be sure to force reloading, the URL is the same so you may be seeing a cached copy.
Jorge Stolfi
#2810
Apr4-11, 11:44 AM
P: 279
Could someone please explain how TEPCO is measuring the temperatures, pressures, and CAMS readings?

AFAIK all electronic instruments are inoperative and no one can get close to the reactors. So I presume that they are measured through pipes or thermocouple wires that extend to some place outside the buildings. Is that the area where the fire extinguishing pipes begin?
|Fred
#2811
Apr4-11, 11:53 AM
P: 312
it is my understanding that gauges are and have been working in the control room (analog power?) as they had to go every now and then to check the value with torch light.. and now they have regular cellar light
Astronuc
#2812
Apr4-11, 12:09 PM
Admin
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Quote Quote by WhoWee View Post
Is it possible at any point to blow a powdered alloy (or perhaps a multi-staged application) onto the damaged cladding that might coat and repair the damage - at least temporarily - then repeat the process?
As far as I know, that would not work, partly because the fuel is supposed to be underwater, there is no way to ensure uniform or appropriate distribution, and there is no satisfactory binder.

They could conceivable dump a bunch of resin powder or beads in the pool. Normally, the coolant or condensate is 'polished' in a filter demineralizer that is a basically a huge filter with a resin coating - much like in principle a 'green sand' filter.

There are two groups of fuel to be concerned about, the fuel in the SFPs and the fuel in the core. If any fuel is damaged, it will be a radiological risk.

Reactor personnel have to deal with failed fuel on occassion (although there has been a program in place for over a decade to drive failure rates to zero). Normally, it's one or a few assemblies with typically 1 failed fuel rod. We maybe looking at 100s or thousands of failed rods, and that's very complicated from a radiological standpoint. If the tie rods are failed, then special tooling will be required to fish the damaged fuel out of the core. In fact, special baskets may be necessary in order to remove damaged fuel.

Hopefully, there are some fuel assemblies in the core which are intact - basically the low power assemblies at the periphery of the core, or the low burnup fuel.

I'd surely like to know the state of the fuel in the SFPs of Units 1-4, particularly unit 4. I suspect 4 has the most damaged fuel, and I'm not sure of the others.
tsutsuji
#2813
Apr4-11, 12:10 PM
PF Gold
P: 1,220
Discussing the black smoke at reactor 3 (probably that black smoke which was reported on 23 March), Kenichi Ohmae suspects the reactor pressure vessel is perforated : http://www.nikkeibp.co.jp/article/co...T=business&P=2
Bodge
#2814
Apr4-11, 12:46 PM
P: 145
Quote Quote by PietKuip View Post
There is also a metastable isomer of this isotope, see http://nucleardata.nuclear.lu.se/nuc...asp?iZA=520429

It has a half-life of 33.6 days, and most of it (63 %) decays to the ground state by emitting a gamma. So the ground state is expected to be in the spectra. In steady state ("equilibrium"), it should be in the data with 63 % of the activity of the metastable isomer.

Its presence does not prove any recent criticality. It does not even point to recent criticality.
Really looks like Gunderson should keep his gob shut.

If CL-38 detection was real then that would be the 'smoking gun'.
michael200
#2815
Apr4-11, 12:56 PM
P: 17
It is reported that the cause of the unit 4 building damage was a H2 explosion caused by overheating of the discharged fuel in the U4 spent fuel pool. To the best of my knowledge, there is no photgraphic evidence of the explosion. Something that has troubled me since the first pictures of the Unit 4 damage on 16March, was whether there actually was a loss of inventory in the U4 spent fuel pool. Attached is a markup of the first photograph that was released on 16 March showing the U4 buiding damage. One can find the photo on Reuters site. This photo was taken before any water injection/spray in Unit 4. Perhaps, I'm missing something, but it sure looks to me like there was still significant water in the fuel pool on March 16. Anyone have an alternative speculation?
Attached Files
File Type: pdf Unit4_Crop_jpg_1257768cl-8.pdf (53.5 KB, 136 views)
sp2
#2816
Apr4-11, 01:11 PM
P: 46
Quote Quote by 83729780 View Post
http://www.nytimes.com/2011/04/05/wo...n.html?_r=1&hp

runoff flooding the turbine buildings of 5 and 6? Implies that an entire swath parallel to the ocean is flooded. 5 and 6 are quite far from 1-4


Don't forget, they did all get hit by a series of very large waves.

(I don't know if water in the basements of 5 and 6 necessarily came all the way over from runoff from 3 and 4.)
TCups
#2817
Apr4-11, 01:19 PM
TCups's Avatar
P: 494
Quote Quote by michael200 View Post
It is reported that the cause of the unit 4 building damage was a H2 explosion caused by overheating of the discharged fuel in the U4 spent fuel pool. To the best of my knowledge, there is no photgraphic evidence of the explosion. Something that has troubled me since the first pictures of the Unit 4 damage on 16March, was whether there actually was a loss of inventory in the U4 spent fuel pool. Attached is a markup of the first photograph that was released on 16 March showing the U4 buiding damage. One can find the photo on Reuters site. This photo was taken before any water injection/spray in Unit 4. Perhaps, I'm missing something, but it sure looks to me like there was still significant water in the fuel pool on March 16. Anyone have an alternative speculation?
@Michael200

Compare your image to this:

http://i306.photobucket.com/albums/nn270/tcups/FHM.jpg

The "reflection" seems dubious. More likely, you are seeing more of the substructure below the operator's platform than a reflection.
michael200
#2818
Apr4-11, 01:38 PM
P: 17
Your picture is of a different refueling bridge design.
MadderDoc
#2819
Apr4-11, 01:49 PM
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P: 698
Quote Quote by Jorge Stolfi View Post
Whether the lid is in place or not: The explosion on #3 blasted away the concrete columns on the N, S, and W sides of the building, but left the E columns mostly in place. The metal beams of the roof that were above the crane remained attached to the columns, and presumably so did the crane. Thus it is possible that the ro the crane remained attached to the columns, and presumably so did the crane. Thus it is possible thof and crane were partially lifted by the explosion, pivoting on the W side, and then fell back to their original positions (except for the lack of support on the E side).
However, from looking at
http://www.youtube.com/watch?v=ZKFGavZ_rf4
(at time stamps about 10:13:27, and about 10:20:28)
those beams and with them the crane do indeed seem to have fallen flat on the floor -- smack on top of the lid, and with steam gushing out from under it.
Attached Thumbnails
cranebeamsonfloor.jpg   cranebeamsonfloor2.jpg  
TCups
#2820
Apr4-11, 01:49 PM
TCups's Avatar
P: 494
Quote Quote by michael200 View Post
Your picture is of a different refueling bridge design.
Your reflection is equivocal at best.
TCups
#2821
Apr4-11, 01:50 PM
TCups's Avatar
P: 494
Quote Quote by MadderDoc View Post
However, from looking at
http://www.youtube.com/watch?v=ZKFGavZ_rf4
(at time stamps about 10:13:27, and about 10:20:28)
those beams and with them the crane do indeed seem to have fallen flat on the floor -- smack on top of the lid, and with steam gushing out from under it.
Look back carefully at the debris on the ground at west side of Bldg 3 and you will see why the crane fell.
NUCENG
#2822
Apr4-11, 02:05 PM
Sci Advisor
P: 916
Quote Quote by TCups View Post
Did I hear that the two fatalities were in the basement of Bldg 4 -- I can't remember for sure? If they were working in the basement of Bldg 4, then were they perhaps trying to do just that when the explosion occurred?
Press Release (Apr 03,2011)
Employees of TEPCO Who Were Missing at Fukushima Daiichi Nuclear Power Station


Due to the Tohoku-Taiheiyou-Oki Earthquake which occurred on March 11th
2011, two TEPCO employees, who had been working at the turbine building
of Unit 4
for site investigation, went missing.
We had put all our strengths to search them, and approximately at 3:25 pm
and at 3:53 pm, today, March 30th, 2011, those employees were found at
the basement of the turbine building and we confirmed their death
yesterday.
We would like to offer our deep regret that our workers died while
working at the plant and heartfelt condolences to the bereaved families.

[Deceased Employees of TEPCO]

Kazuhiko Kokubo (Age: 24) Operation Management Department One, Fukushima
Daiichi Nuclear Power Station
Yoshiki Terashima (Age: 21) Operation Management Department One,
Fukushima Daiichi Nuclear Power Station
WhoWee
#2823
Apr4-11, 02:09 PM
P: 1,123
Quote Quote by NUCENG View Post
[Deceased Employees of TEPCO]

Kazuhiko Kokubo (Age: 24) Operation Management Department One, Fukushima
Daiichi Nuclear Power Station
Yoshiki Terashima (Age: 21) Operation Management Department One,
Fukushima Daiichi Nuclear Power Station
I'm quite surprised by the ages (24 and 21) of the deceased workers.
TedNugget
#2824
Apr4-11, 02:21 PM
P: 15
Pure speculation:

Ages 24 and 21 sound like workers who were sent to do something even though there was a Tsunami Alert.
Their listing in the press release just includes their names and division, no titles but could operation Management mean they were in a higher pay grade?
If not, that would mean (a) supervisor(s) still living with guilt.

That they were in Turbine 4, which one would assume everyone on site knew reactor 4 was down, could indicate the caution they had relating to the spent fuel pool. (With the Turbine buildings holding condensers and providing cooling for both the reactor and SFP).
The workers were found in a basement - auxiliary control room as I recall.
AntonL
#2825
Apr4-11, 02:28 PM
P: 521
I have managed to identify the shared pool No. 7 for very old fuel
one of the thermal images had it labelled in Japanese

It is west of reactor No. 4
Attached Thumbnails
sharedPool`1.jpg  
MadderDoc
#2826
Apr4-11, 03:14 PM
MadderDoc's Avatar
P: 698
Quote Quote by michael200 View Post
..Perhaps, I'm missing something, but it sure looks to me like there was still significant water in the fuel pool on March 16. Anyone have an alternative speculation?
I'll think about that. Looking down in the unit 4 sfp with the more recent crane camera there just appears me to be 'something dark' down there -- judging from the railings seen on the far side of the pool, that surface is several meters below floor level --, and it does not look like water. (Alas, seeing steam obviously does continually escape from the pit, there must be some water down there, still
Attached Thumbnails
lookingdownat_spf4_a.jpg   lookingdownat_spf4_b.jpg  


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