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Japan Earthquake: nuclear plants

by gmax137
Tags: earthquake, japan, nuclear
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TCups
#7201
May14-11, 07:52 AM
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Quote Quote by MadderDoc View Post
Based on the available data of the reactor parameters, the combined system of RPV and support plumbing of unit 3 failed already on March 13th (between 9:10 and 9:25 the RPV pressure dropped abruptly from 7.3 MPa to 0.45 MPA, while drywell pressure increased from 0.46 to 0.53 MPa.) This would seem to imply that the dozen or so preventive relief valves you mention, failed too.

Consequently, on March 14th, the day of the explosion, the RPV and the PCV were no longer sharply separated volumes, and a depressurizing of the PCV at that stage would also lead to a depressurizing of the RPV . The data available up to and after the explosion indicates a depressurizing of both vessels in connection with the explosion of no less than 0.1 MPa.
Or, might it simply imply that the pressure relief valves were bypassed, as by damage and subsequent rupture of one of the connecting feed lines, especially the high pressure steam lines near the top of the RPV? Would that not produce the same observations?

It has been reported that lateral forces of the quake exceeded the design limits of Unit 3.
jim hardy
#7202
May14-11, 07:53 AM
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""The only strange thing is the apparent contraction and as some have said bulging of unit 3 just before the explosion, compare frames 000ms and 040ms, """

i have speculated whether there might have been a near invisible hydrogen flame already leaving the building at those first instants, it distorted the image while the flying debris took a few milliseconds to accelerate from rest.

warn me when i approach the line, guys.
jim hardy
#7203
May14-11, 08:06 AM
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Maddrr Doc neither do i have access to logs and may be having a senior moment.
Here's some notes about venting unit 1, i could be remembering wrong unit.

>>>>>>>
Anger rose as TEPCO dithered

TEPCO began preparations for opening the valves around 7 p.m. on March 11. Pressure inside the No. 1 reactor was particularly high.

"Soon, the reactor won't be able to withstand the pressure," said an official of the accident headquarters at the plant, which was keeping in touch with TEPCO's head office via video phone. "We have to vent the pressure immediately."

"Pressure inside the containment vessel of the No. 1 reactor has gone up dramatically," the agency told Banri Kaieda, economy, trade and industry minister, at 12:45 a.m. on March 12. In fact, it had reached 1.5 times the designed maximum, meaning the condition of the reactor was critical.

"To get things under control, we have to pour water into the reactors and then vent the steam that is generated," Haruki Madarame, chairman of the Cabinet Office's Nuclear Safety Commission, told Kaieda.

At 1:30 a.m. on March 12, Kan, Kaieda and Madarame gathered at the crisis management center in the basement of the Prime Minister's Office.

The three urged TEPCO officials to vent the steam as soon as possible. But TEPCO officials said there was no way of opening the valves because there was no power supply.

Exasperated, Kaieda called the utility's head office in Tokyo and the accident headquarters at the plant every hour, pressuring them to open the valves immediately.

TEPCO workers tried to open the valves by manually overriding the automatic system, but struggled to make progress because they had to work in darkness.

At dawn, pressure inside the No. 1 reactor was more than twice the designed maximum.

Eventually, at 6:50 a.m., the government ordered the utility to open the valves under the Nuclear Reactor Regulation Law.

When Kan visited the accident site shortly after 7 a.m. and found TEPCO had not opened the valves yet, he reprimanded company officials. The officials replied they would like to have another hour to make a decision on what to do.

Kan blew his stack.

"Now's not the time to make such lackadaisical comments!" the prime minister told the TEPCO officials.

Yet even still, the utility spent three more hours discussing the matter before finally opening the valves at 10:17 a.m.

Five hours after that, a hydrogen explosion occurred at the No. 1 reactor, blowing apart its outer building.

via Yomiuri



source http://www.houseofjapan.com/local/te...lant-emergency
MadderDoc
#7204
May14-11, 08:26 AM
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Quote Quote by AntonL View Post
<..>
The contraction I attribute to a mpeg compression or sharpening artifact, but why the west wall should suddenly reflect less light - possibly already starting to crumble or shake as a reaction of what is happening inside.
If you can attribute the contraction to artefacts why not go the full Monty and attribute the lessening of reflection from the west wall to artefacts too? Using the 'artefacts' card, nothing in a video should really be inexplicable :-)

No seriously. You should establish for yourself a baseline looking at a series of frames before 000ms. How much bulging and contracting do you see there, how does it look when nothing is ongoing in the building, how much can it all wobble due to artefacts?

I think you will not likely find a contraction similar to the one you see in frame 040ms in any frames before frame 000ms. If that is so, then what you see is an aberration in relation to your baseline and therefore unlikely an artefact. It is the real thing, something is really changing. Same goes for what you see on the west wall.

(You may consider using another video source, the one you have been using appears to have been recompressed resulting in loss of information)
AntonL
#7205
May14-11, 08:36 AM
P: 521
Tepco admit to the possibility that all primary containment vessels of all reactors are leaking.

english article: http://www.asahi.com/english/TKY201105130192.html
japanese article: http://www.asahi.com/national/update...105140387.html
which also talks of that the cooling plan for Unit 1 will most likely be abandoned.
3000Tons of water is missing from the unit 1 containment, possibly in the torus basement and also leaked into the ground water.

Also here is the english article of the leaked 100 page report http://www.asahi.com/english/TKY201105130370.html
rowmag
#7206
May14-11, 09:20 AM
P: 209
Quote Quote by AntonL View Post
Tepco admit to the possibility that all primary containment vessels of all reactors are leaking.

english article: http://www.asahi.com/english/TKY201105130192.html
japanese article: http://www.asahi.com/national/update...105140387.html
which also talks of that the cooling plan for Unit 1 will most likely be abandoned.
3000Tons of water is missing from the unit 1 containment, possibly in the torus basement and also leaked into the ground water.

Also here is the english article of the leaked 100 page report http://www.asahi.com/english/TKY201105130370.html
English version says 3000 tons of water missing, Japanese version says 3000 tons of water found in basement.

So what now? Fill the basement with cement?
robinson
#7207
May14-11, 09:37 AM
P: 201
I don't think it's speculation to say this is the biggest nuclear mess mankind has ever faced.
swl
#7208
May14-11, 09:41 AM
P: 108
Quote Quote by jim hardy View Post
""The only strange thing is the apparent contraction and as some have said bulging of unit 3 just before the explosion, compare frames 000ms and 040ms, """
My opinions:

The building was not contracting. The upper containment walls are beginning to expand in the "0" frame. I can see that the dark roof outline has not moved down, but the white color of the wall does appear to have moved down at the upper edge.

As has been noted, H.264 compression uses inter-picture prediction over as many as 16 frames. This codec is intended to provide very high data compression while maintaining reasonable -motion- picture quality. When set up for streaming video, like on youtube, the data is optimized for a motion picture where you view each frame for 1/25th of a second. It can not be relied upon to provide fidelity of an individual frame for still analysis.

In addition to being subjected to H.264 conversiom, avi conversion, and pray tell what else, the quality of the master was almost certainly of poor quality with low resolution, poor contrast and atmospheric distortion.

Question: Having done my bast to discredit the reliability of the video, does it look to any of you like the ignition point might have been outside the upper southwest corner?
AntonL
#7209
May14-11, 09:47 AM
P: 521
Quote Quote by MadderDoc View Post
re unit 3


I have no access to the plant logs, only notes I took of press releases at the time of the events, and of observations of the webcam.
Here are excerpts, just what I find may be relevant to your question:

March 12th
11:00 Preparing to implement a measure to reduce the D/W pressure (i.e. venting)

March 13th
08:41 Venting procedure finished
08:56 Radiation at site boundary exceeds limits
09:10-09:25 Large drop of RPV pressure, with increase of DW pressure
10:00 webcam shows vent from unit 3 exhaust stack
13:00 webcam shows vent from unit 3 exhaust stack
14:00 webcam shows vent from unit 3 exhaust stack
14:00 Sea water injection is being attempted followed by boric acid injection
14:00 Safety relief valve has been opened manually

March 14th:
05:00 Water level that has been held at about -2.3 m relative to fuel top goes downscale
06:00 DW and SC pressure goes above design max limits
07:00 Water level comes back within scale, but only at -3.0 m relative to fuel
08:00 Water level indicators erratic or water level unstable
11:01 Explosion
Extracted from NISA status report for Unit 3 http://www.nisa.meti.go.jp/english/f...110513-1-2.pdf

March 11th 15:42 Report based on the Article 10 (Total loss of A/C power)
March 13th 05:10 Occurrence of the Article 15 event (Inability of water injection of the Emergency
Core Cooling System)
March 13th 08:41 Started to vent.
March 13th 13:12 Started to inject seawater and borated water to the Reactor Core.
March 14th 05:20 Started to vent.
March 14th 07:44 Occurrence of the Article 15 event (Unusual rise of the pressure in PCV)
March 14th 11:01 Sound of explosion
March 16th around 08:30 White smoke generated.
AntonL
#7210
May14-11, 09:57 AM
P: 521
Quote Quote by robinson View Post
I don't think it's speculation to say this is the biggest nuclear mess mankind has ever faced.
yes you a right, Chernobyl vaporized their core and spread it over a large area, Fukushima are dissolving their core and burying it in their ground water.
turi
#7211
May14-11, 10:05 AM
P: 46
Quote Quote by MadderDoc View Post
re unit 3
[...]
March 14th:
05:00 Water level that has been held at about -2.3 m relative to fuel top goes downscale
06:00 DW and SC pressure goes above design max limits
07:00 Water level comes back within scale, but only at -3.0 m relative to fuel
08:00 Water level indicators erratic or water level unstable
[...]
Does anyone here know how those water level sensors work? What could cause them to give erronous info (instead of simply appear offscale or stuck)? If the newly attempted measurements at unit 1 are to be believed the two sensors there showed erronous info for quite some time. Also interesting might be that they both showed more or less the same values. How do two of those sensors go awry in the same way?
MadderDoc
#7212
May14-11, 10:08 AM
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Quote Quote by GJBRKS View Post
The calculations do not concern themselves with the environmental temperatures.
No, and that's what strikes me as odd. It is as if this RPV is suspended in empty space at absolute zero- Otherwise I cannot see how one can avoid involving a term representing the temperature of the environment. A blackbody is something that would absorb all radiation incident on it, if I understand that term? It would seem to have to emit that amount of energy again plus the internally produced heat in order to reach an equilibrium temperature. I think.
GJBRKS
#7213
May14-11, 10:29 AM
P: 82
Quote Quote by MadderDoc View Post
No, and that's what strikes me as odd. It is as if this RPV is suspended in empty space at absolute zero- Otherwise I cannot see how one can avoid involving a term representing the temperature of the environment. A blackbody is something that would absorb all radiation incident on it, if I understand that term? It would seem to have to emit that amount of energy again plus the internally produced heat in order to reach an equilibrium temperature. I think.
Yes ,but :
- considering that the environment is a heatsink and therefore in equilibrium it contributes to an equivalent constant inward flux of 419 W/m^2 (at 20 degrees celsius) , therefore this is a negligable amount considering the uncertainties of the whole.

We can extrapolate likewise for higher temperatures in the surrounding containment :

100 degrees Celsius containment would amount to an additional 1100 W/m^2 above the 15100 W/m^2 for reactor 2 and 3 , thereby increasing the temperature line to 475 degrees from 445 degrees calculated before , so that would be +30 degrees celsius
MadderDoc
#7214
May14-11, 10:29 AM
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Quote Quote by swl View Post
Does it look to any of you like the ignition point might have been outside the upper southwest corner?
I think no one can claim to have actually seen the ignition. It would seem to me to be an extraordinary claim that the ignition point was outside the building. I would like to hear about the supposed mechanism for such occurrence before even considering it.
dh87
#7215
May14-11, 10:53 AM
P: 39
Quote Quote by Jorge Stolfi View Post
I have fallen behing with my plots due to other work. But now I wonder whether it is worth keeping them updated.

For one thing, TEPCO has been releasing a lot more readings and more often, including plots; and other people have been doing it too.

More seriously, the latest news about #1 mean that *both* its water level readings, for the past two months, were garbage --- not inaccurate, not biased, not noisy, but just total garbage. Since the readings for #2 and #3 have similar values and behavior, it is very likely that they are garbage too. (Indeed the black smoke event for #3 sems to coincide with some major event in the RPV emperatures and other variables --- a core breach perhaps?)

Now what trust can we put in the other measurements? I have this mental image of a room somewhere in the reactor building, half-full with water, with a big chunk of fallen concrete in the middle and all the pressure and water level gauge pipes disappearing under it. Or of the "RPV bottom" termocouple inside the drywell, hanging in mid-air by its wires, gently swaying under a drizzle of warm borated water from a ruptured pipe pipe above.

Anyway, I will think about it over the next weekend, when I have more time. Sorry... and all the best.
Thank you for all the work in maintaining your graphs. They've helped me to try to think about what's been happening. Even if I am 20 pages behind on reading this forum.
mikefj40
#7216
May14-11, 11:12 AM
P: 26
Quote Quote by NUCENG View Post
The different photon energy possibilities are listed in the nuclide table. Other types of decays are also listed in the nuclide table with a description of the energy levels. just click on the decay type and it will give you the decay energy diagrams.

http://atom.kaeri.re.kr/index.html
Thanks again... I have some reading to do after Saturday chores!
MadderDoc
#7217
May14-11, 11:14 AM
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Quote Quote by GJBRKS View Post
Yes ,but :
- considering that the environment is a heatsink and therefore in equilibrium it contributes to an equivalent constant inward flux of 419 W/m^2 (at 20 degrees celsius) , therefore this is a negligable amount considering the uncertainties of the whole.
Yes, I can understand that, and I agree this is a negligible amount.

We can extrapolate likewise for higher temperatures in the surrounding containment :

100 degrees Celsius containment would amount to an additional 1100 W/m^2 above the 15100 W/m^2 for reactor 2 and 3 , thereby increasing the temperature line to 475 degrees from 445 degrees calculated before , so that would be +30 degrees celsius
Yes, I see, however now we are getting close to my pain threshold for negligible terms. In conclusion, if I understand this now :-), the calculation does strictly yield the maximum surface temperature of a RPV suspended in empty space at absolute zero -- but this is with good approximation the same as the maximum surface temperature in an environment (I assume, to be able to neglect other heat transfer, a low density environment, e.g. air), at up to about 100oC.
MadderDoc
#7218
May14-11, 11:28 AM
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Quote Quote by turi View Post
Does anyone here know how those water level sensors work? What could cause them to give erronous info (instead of simply appear offscale or stuck)?
My understanding is that when water gets low and the going gets tough in a reactor, there _is_ no well-defined water level anymore to measure. When the water level starts jumping up and down, its time for duck and cover.


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