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Japan Earthquake: nuclear plants

by gmax137
Tags: earthquake, japan, nuclear
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|Fred
#4393
Apr20-11, 09:59 AM
P: 312
Quote Quote by Joe Neubarth View Post
That is amazing! Something so very obvious as the data from Reactor Two and nobody appears to understand what is happening.
Reactor Two is NOT venting steam.

In fact the top of the reactor is considerably higher than the temperature of steam. Steam can only go to a higher temperature if it is under pressure, which it is not in this case. Reactor two is venting hot radioactive gases.

So,I ask my question in the morning that I asked at night. Does anybody have any theories as to how the water is missing the core which has to be out of containment at this time. Are we going to see a continued release of hot radioactive gases until the BLOB has diluted itself, or will they continue for a generation or so?
Sorry, You'll probably get amassed as I don't get it, you are saying that visually looks like steam/ exiting unit 2 is not steam but Gaz ? Because RCV is not pressurized and the top of the reactor is to hot ?
What do you think happens when the watter enter the hot RCV ? or does it enter at all?


edit: ah... no you are saying that there is no longer steam exiting unit 2... oh well all I was asking is when has it been reported.. nothing more, nothing less
jlduh
#4394
Apr20-11, 09:59 AM
P: 468
more than 67 000 tons of contaminated water accumulated at the Daichi plant...

http://www3.nhk.or.jp/daily/english/20_30.html

And i don't see how the accumulation of water would stop in the next month as long as they will have to continue to keep cooling down the stuff in open loop! A second ongoing flooding after the tsunami one...

What are the alternatives (if any exists)?
clancy688
#4395
Apr20-11, 10:00 AM
P: 546
Quote Quote by default.user View Post
Ich habe mich gefragt, ob es Tepco überhaupt möglich ist, die Reaktoren direkt zu kühlen, oder ob man die Druckbehälter via containment kühlt. Eine sehr wichtige Frage.
Scheinbar ist das noch nicht der Fall. Zumindest wurde in dem TEPCO-6-Monatsplan angegeben, dass in naher Zukunft die Containments der Reaktoren 1 und 3 mit Wasser geflutet werden. Was heißt, dass es jetzt noch nicht der Fall ist.

That's probably not the case. The recently announced TEPCO-6-month-plan stated, that they'll fill the containments of Units 1 and 3 with water in the near future, indicating that they're currently dry and unfilled.
Rive
#4396
Apr20-11, 10:03 AM
P: 357
Quote Quote by elektrownik View Post
Who want explain why core temperature (empty core as tepco say) is 11C bigger than SFP ?
http://www.mod.go.jp/j/approach/defe...ren/230420.pdf
We can't see the SFP directly, so the temperature what the senor see is some mixture of the temperature of the roof and the FHM. The SFP temperature of Unit 4 is close to the boiling point by the direct measurement (some sample were taken by the concrete pump truck along with a direct temperature measurement.)
Joe Neubarth
#4397
Apr20-11, 10:04 AM
P: 238
Quote Quote by clancy688 View Post
Scheinbar ist das noch] nicht der Fall. Zumindest wurde in dem TEPCO-6-Monatsplan angegeben, dass in naher Zukunft die Containments der Reaktoren 1 und 3 mit Wasser geflutet werden. Was heißt, dass es jetzt noch nicht der Fall ist.
There are too many unanswered questions and the Japanese are not in position to answer them.
jlduh
#4398
Apr20-11, 10:05 AM
P: 468
The emergency generators at the No. 2 [that is Daini] plant were in buildings housing the reactor cores. Because the reactor buildings are much more airtight, the generators at the No. 2 [Daini] plant continued to function after the tsunami struck.
http://www.asahi.com/english/TKY201104060126.html
Tanks tsutsuji, that looks to me a significant difference between the two if this is confirmed. I believe based on one drawing that i saw (but i don't find it again) that the EDG at Daichi were in fact below the ground level in the reactor buiding which is not intended to be waterproof of course... One can imagine the consequences in case of flooding. Pure stupidity. Putting them in the reactor building seems more intelligent, even if maybe they should have put them on the hills around the plant!
Joe Neubarth
#4399
Apr20-11, 10:07 AM
P: 238
Quote Quote by jlduh View Post
Tanks tsutsuji, that looks to me a significant difference between the two if this is confirmed. I believe based on one drawing that i saw (but i don't find it again) that the EDG at Daichi were in fact below the ground level in the reactor buiding which is not intended to be waterproof of course... One can imagine the consequences in case of flooding. Pure stupidity.
Absolute pure stupidity. They did not design for the run up from a tsunami. Somebody gave the engineers a number for tsunami height, but it looks like they airheaded the engineering.
tsutsuji
#4400
Apr20-11, 10:11 AM
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P: 1,220
Quote Quote by Joe Neubarth View Post
To be precise, the tsunami was only about four meters. The run up from the tsunami reaching land was in excess of 14 meters.

San Onofre in San Diego County is not designed to withstand a run up in excess of 9 meters, which can be caused by a tsunami half that height. And yet, San Onofre is still allowed to operate with over 3 million people living within 50 miles of the site.
Do you have a source for the "about four meters" ?

Looking at the "predicted maximum level caused by tsunami O.P. 5.7 meter" caption leading via the blue arrow to the red dots just above the sea wall at http://www.tepco.co.jp/en/press/corp...s/110409e9.pdf , I am wondering how tall that sea wall is. If the sea wall is 5.7 m high and the tsunami only "about four meter" high, should not the nuclear plant have been safe then ?

I would be glad to read more basic science on this topic : how tsunami height and tsunami "run up" are related with each other and possibly modelized, and how sea walls are designed to ensure some predicted level of protection.

What is the meaning of the "O.P." acronym ?
|Fred
#4401
Apr20-11, 10:16 AM
P: 312
Ich habe mich gefragt, ob es Tepco überhaupt möglich ist, die Reaktoren direkt zu kühlen, oder ob man die Druckbehälter via containment kühlt. Eine sehr wichtige Frage.
he ask him self if tepco has to cool the core from the inside or if could be cooled from the outside (I think)

If I understand you right.. by design it is meant to be cooled from the inside of the RCV. In case of an accident cooling from the outside seems to be procedure because it can help a bit . is it a good solution ? thats debatable.

Ob ich Sie verstehe .. von Design ist gemeint, von der Innenseite des Reactor vessel gekühlt werden.Im Falle eines Unfalls Kühlung von außen scheint Verfahren. Es hilft .I st es eine gute Lösung? thats fraglich.
tsutsuji
#4402
Apr20-11, 10:24 AM
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P: 1,220
Quote Quote by Joe Neubarth View Post
Absolute pure stupidity. They did not design for the run up from a tsunami. Somebody gave the engineers a number for tsunami height, but it looks like they airheaded the engineering.
At least "Tsunami assessment for nuclear power plants in Japan" by M.Takao, TEPCO : http://www.jnes.go.jp/seismic-sympos...sionB/B-11.pdf (1st Kashiwazaki International Symposium on Seismic Safety of Nuclear Installations, November 2010), page 14, seemed confident in the 4.4 + 1.3 = 5.7 m calculation, whatever that might mean.
clancy688
#4403
Apr20-11, 10:32 AM
P: 546
Quote Quote by tsutsuji View Post
At least "Tsunami assessment for nuclear power plants in Japan" by M.Takao, TEPCO : http://www.jnes.go.jp/seismic-sympos...sionB/B-11.pdf, page 14, seemed confident in the 4.4 + 1.3 = 5.7 m calculation, whatever that might mean.
Well, in case of Onagawa they didn't stick with those 5.7 metres but went far beyond. http://search.japantimes.co.jp/cgi-b...0110408b3.html
default.user
#4404
Apr20-11, 10:38 AM
P: 28
Quote Quote by |Fred View Post
Ich habe mich gefragt, ob es Tepco überhaupt möglich ist, die Reaktoren direkt zu kühlen, oder ob man die Druckbehälter via containment kühlt. Eine sehr wichtige Frage.

If I understand you right.. by design it is meant to be cooled from the inside of the RCV. In case of an accident cooling from the outside seems to be procedure because it can help a bit . is it a good solution ? thats debatable.

Ob ich Sie verstehe .. von Design ist gemeint, von der Innenseite des Reactor vessel gekühlt werden.Im Falle eines Unfalls Kühlung von außen scheint Verfahren. Es hilft .I st es eine gute Lösung? thats fraglich.
Das ist fraglich.

Es ist doch auch fraglich, ob man einen in Kernschmelze befindlichen Druckbehälter ohne Problem [Wasserdampfexplosion] direkt kühlen kann.

Wenn man nicht weiß, wie der Zustand der Kerne ist, so wird man doch sicher keine Fehler machen wollen.

About 130 minutes after the first malfunction, the top of the reactor core was exposed and the intense heat caused a reaction to occur between the steam forming in the reactor core and the Zircaloy nuclear fuel rod cladding, yielding zirconium dioxide, hydrogen, and additional heat
http://en.wikipedia.org/wiki/Three_M...of_stuck_valve

Wie lange war die Kühlung in Daiichi unterbrochen?
tsutsuji
#4405
Apr20-11, 10:45 AM
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P: 1,220
Quote Quote by clancy688 View Post
Well, in case of Onagawa they didn't stick with those 5.7 metres but went far beyond. http://search.japantimes.co.jp/cgi-b...0110408b3.html
[At Onagawa] The recorded tsunami height of about 13 meters far exceeded the plant's anticipated maximum level of 9.1 meters, and wave marks were found at the edges of the plant, indicating the tsunami fell just short of reaching the main buildings, Tohoku Electric said.
http://search.japantimes.co.jp/cgi-b...0110408b3.html
See also IAEA/JNES/NIED Seminar on Nuclear Disaster & General Disaster Management against Tsunami and Earthquake, Tokyo, December 2007, “Safety Assessment and Disaster Management for Tsunami Hazards at Onagawa Nuclear Power Plant”, Y. Matsumoto, (Tohoku Epco, Japan) : http://www.jnes.go.jp/content/000015486.pdf (in Japanese, but pictures , diagrams and mathematical formulas may provide some information even if you don't read Japanese)

In particular the diagram p.10 indicates that the ground floor's height is 14.8 m at Onagawa, which was perhaps enough for the 11 March tsunami at that location.
clancy688
#4406
Apr20-11, 10:54 AM
P: 546
Quote Quote by tsutsuji View Post
See also IAEA/JNES/NIED Seminar on Nuclear Disaster & General Disaster Management against Tsunami and Earthquake, Tokyo, December 2007, “Safety Assessment and Disaster Management for Tsunami Hazards at Onagawa Nuclear Power Plant”, Y. Matsumoto, (Tohoku Epco, Japan)
Wow. The tsunami-chart is interesting. They plotted wave heigths along the coast for three major tsunamis (1611, 1896, 1933).
But at the Onagawa location, all of these three tsunamis were around 5 metres. The really big wave heights of 20 metres and more were reached on the shore starting at 100 km north of the plant location.

Warning, highly speculative:
So that's probably one of the reasons, they only build Daiichi 10 metres above sea level and not really water proof - because historic tsunamis didn't reach 15 metres at Fukushima which's between 100 and 200 km south of Onagawa...?
PietKuip
#4407
Apr20-11, 11:01 AM
P: 184
Quote Quote by default.user View Post
Wie lange war die Kühlung in Daiichi unterbrochen?
Cooling at Fukushima was interrupted for longer times than at Three Mile Island, but this was several hours after the chain reaction had been stopped. Thermal power was much lower.
Dmytry
#4408
Apr20-11, 11:01 AM
P: 505
Quote Quote by clancy688 View Post
Wow. The tsunami-chart is interesting. They plotted wave heigths along the coast for three major tsunamis (1611, 1896, 1933).
But at the Onagawa location, all of these three tsunamis were around 5 metres. The really big wave heights of 20 metres and more were reached on the shore starting at 100 km north of the plant location.

Warning, highly speculative:
So that's probably one of the reasons, they only build Daiichi 10 metres above sea level and not really water proof - because historic tsunamis didn't reach 15 metres at Fukushima which's between 100 and 200 km south of Onagawa...?

Sounds stupid. Should of been built to at least withstand max historical tsunami height for entire coast there, the crack goes all the way along. They've de-rated lifetime risk of failure for that plant to worse than 1/100 if we assume that max wave height location is approximately random.
clancy688
#4409
Apr20-11, 11:03 AM
P: 546
Quote Quote by TCups View Post
Building 4 has already exploded. Two panels have blasted out of the east side and impacted on the west facade of the turbine building for Unit 4, and smoke is pouring out of the east side of Building 4.
One last comment to that idea:

I checked the T-Hawk Video for the two impact spots you mentioned. There's a guard rail or something like this going along the turbine building. But the debris is sticking between the guard rail and the building, indicating it's come from above.

If it has come from the east side of Unit 4, it should have smashed the guard rail. But that's not the case. The impact damage on the west side of the turbine building origins in the blast at Unit 3. The smoke is probably an optical illusion, it's most likely smoke from Unit 3 as well.
Attached Thumbnails
Fukushima flight april 15th smooth motion.flv_snapshot_03.36_[2011.04.20_17.58.53].jpg  
Borek
#4410
Apr20-11, 11:04 AM
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P: 23,581
Quote Quote by default.user View Post
Das ist fraglich.
Quote Quote by |Fred View Post
[I]Ich habe mich gefragt, ob es Tepco überhaupt möglich ist, die Reaktoren direkt zu kühlen, oder ob man die Druckbehälter via containment kühlt.
Quote Quote by Samy24 View Post
Das kann man nicht sicher ausschließen.
Quote Quote by clancy688 View Post
Scheinbar ist das noch nicht der Fall.
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