Japan Earthquake: nuclear plants

*Joe Neubarth*

Quote by clancy688

I think, Daiichi 1-4 are at 10 metres elevation. 5-6 and Daini 1-4 are at 14 or 15 metres elevation.

The tsunami had a height of 14-15 metres. So there's your explanation.

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.

tsutsuji

Trying to find basic information on Areva's water treatment facilities :

The used fuel treatment station at La Hague also manages liquid wastes.

In this facility at La Hague, AREVA treat the liquid releases.
http://www.areva.com/EN/operations-1...-la-hague.html

*Joe Neubarth*

Quote by clancy688

I have currently no sources (I'm in class right now), but as far as I remember, Daichi 1-4 have been flooded 5 metres deep and Daiichi 5-6 and Daini 1-4 only 1 metre deep.

I do not remember reading of any wave breaking into the building housing the Diesel generators like it did at Daichi. In the turbine buildings at Daichi, men were killed (severely lacerated) by the wave action inside the building.

jlduh

Quote by Joe Neubarth

I do not remember reading of any wave breaking into the building housing the Diesel generators like it did at Daichi. In the turbine buildings at Daichi, men were killed (severely lacerated) by the wave action inside the building.

So your point is be that the difference would be that at Daini the wave didn't break the walls or doors of the building in which the generators were which was not the case at Daichi?

Can someone confirm with a good source document where were exactly located the EDG at Daichi and Daini? I'm not only talking about their position from the top view (at daichi they are in the east north side of each reactor, in the turbine building) but also their elevation location relative to platform level: at ground level or BELOW ground level?

tsutsuji

Quote by jlduh

So my point is: ok the tsunami has been worse at Daichi than at daini because some difference of height of the platform but still, did the EDG at Daini went under water, or close to go under water too?

http://www.tepco.co.jp/en/press/corp...s/110409e9.pdf

The following 2011/04/07 Asahi article was posted earlier in this thread :

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

default.user

Quote by Samy24

Das kann man nicht sicher ausschließen. Auch Physiker sind sich da nicht einig.

One can not rule out safely. Physicists are not as united.

Eine vollständige und spontane Kernschmelze kann wohl nicht effektiv mit Wasser gekühlt werden. Ob und wie eine Kernschmelze in Fukushima abläuft, weiß man jedoch nicht.

A complete and spontaneous meltdown may well not be effectively cooled with water. Whether and how a meltdown going on in Fukushima, we know not.

Wenn der sehr hoch erhitzte Kern plötzlich auf eine größere Menge Wasser trifft könnte es zu einer Wasserdampfexplosion kommen.

If the very-high temperature nuclear suddenly take on a greater amount of water it could cause a steam explosion.

Vielen Dank.

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.

Also, entweder die Kerne sind geschmolzen und sehr heiß als nicht direkt kühlbar oder sie sind ok und direkt kühlbar.

Abgesehen davon, dass ich mir nur schwer vorstellen kann, dass irgendwelche Hochdruck-Rohrsysteme intakt sind.

|Fred

Quote by Joe Neubarth

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

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

Quote by default.user

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

Quote by elektrownik

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*

Quote by clancy688

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

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*

Quote by jlduh

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

Quote by Joe Neubarth

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

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

Quote by Joe Neubarth

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

Quote by tsutsuji

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

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jlduh	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)?