Japan Earthquake: nuclear plants

AntonL

In above table some RPV temperature is exceeding the design limit of 300^oC.

Please could a kind knowledgeable person translate the headings

triumph61

These two things are moving...??

Attached Thumbnails

 

Rive

I dunno, but those 40 assemblies at the center of the pic are from the last load IMO. Those are the only ones with visible glowing.

Ps: now we have enough pictures to make a drawing about the pool and make some count about the assemblies- at least we will know how many were not seen.

AntonL

Movement due to hot water rising

On the right lower diagonal we see a fuel rack with new fuel. Earlier it was reported that fuel assemblies have plastic cap, I think that is what we are seeing here

MiceAndMen

Thanks to you and the others who commented on it. No apology needed, the misunderstanding was mine.

zapperzero

Careful. Unless I lost some zeroes along the way (all too likely), 1 cubic metre per hour is 278 cubic centimetres per second. That's ONE round bubble about 8 cm across every second (or a number of smaller ones). To put it another way, the average human goes through about half a cubic metre of air an hour.

I'm sure most of what's in those bubbles we see now is steam but... dunno, cubic metres per hour sounds quite as if it were in the realm of the possible, especially if the pool was hotter earlier on (my intuition is more steam means more radiolysis, I bet water self-shields otherwise).

MiceAndMen

Also keep in mind that if the pool is full then the tops of the fuel assemblies are about 8 m under water. The gas in each bubble will occupy a larger volume when it gets to the surface. If that rate of bubble generation is constant and continuous and is H2, it's not insignificant.

imandylite

New video Spent Fuel Pool of Unit 4 of Fukushima Daiichi Nuclear Power Station

YouTube Spent Fuel Pool 4 - 8 May 2011

imandylite

Video of team working Inside of Reactor Building of Unit 1

YouTube New video of reactor 1 working environment 6 May 2011

MadderDoc

Yes. We appear to have seen enough fuel racks to hold the recorded number of assemblies in the pool. Here is a rough lineout of the stacking in the pool, as much as can be gleaned from the two released videos.

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elektrownik

Unit 3 is 314,5C now, this is realy big...

GJBRKS

This morning at 0600 it was 202 C :

http://www.tepco.co.jp/nu/fukushima-...0_05080600.pdf

Do you have a link to the source ? I can't find it at the usual locations ...

(and somehow TBS decides to zoom in on unit 1+2 , leaving unit 3 off camera ...)

imandylite

Just looking at the stats myself

Link:

Stats Unit 3 05/01/11 - 05/08/11

MadderDoc

Here's what Google Translate gives for the headers, (change in the temperatures over the last week)

1. N4B Water Nozzle Temperature (93.7 --> 202.1 gr.C)
2. RPV bottom head top (122.3 --> 255.6 gr.C)
3. RPV flange body (99.6 --> 310.1 gr.C)
4. Lower temperature pressure vessel (116.5 --> 151.9 gr.C)
5. RPV stud temperature (98.8 --> 253.6 gr.C)
6. RPV flange body Lower temperature (154.6 --> 173.3 gr.C)
7. Relief safety valve 2-71D Leakage (91.3 --> 158.2 gr.C)
8. Relief safety valve 2-71F Leakage (96.9 --> 108.8 gr.C
9. Main steam isolation valve 2-86A Rikuofu (61.2 --> 63 gr.C)
10. D/W HVH return temperature (101.7 --> 157.6 gr.C)
11. Bellows RPV (137.3 --> 208.6 gr.C)
12. S/C Pool A water temperature (40.6 --> 40 gr.C)
13. S/C Pool B water temperature (40.6 --> 40 gr.C)

MadderDoc

I can't see how this motive can be anywhere near the spent fuel pool of unit 3.
It looks more like the edge of a pit or a manhole than a spent fuel pool. For a starter, where's the steel liner?

fluutekies

Why should they use enriched B-11? It would be very expensive and scarce. Natural occurring boron contains 20% B-10 with 80% B-11.
Boric acid H₃BO₃, Borax Na₂B₂O₇ and even Boron trioxide B₂O₃ are bulk chemicals and very cheap. (I don't think TEPCO needs high grade qualities anymore ...)

An aqueous solution of the above mentioned chemicals can be prepared either on- or off-site. Really no big deal.

Does anybody know which concentration is needed to effectively absorb neutrons with B to avoid criticality?

MadderDoc

From what I've read, boron is used up to a few thousand ppm in the cooling water.