Published: April 13th, 2012 at 2:52 am ET
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Title: TEPCO Press Conference 4/13/2012 11AM: Reactor 4 SFP Temperature Was 49.9 Degrees Celsius as of 3AM, 4/13/2012
Source: EXSKF
Date: April 12, 2012
UPDATE: Matsumoto was speaking about the Reactor 4 Spent Fuel Pool, and mentioned the temperature. I took to mean the temperature of the SFP, but it is more likely that Matsumoto suddenly switched back to talking about the temperature of the Reactor 1 dry well. Sorry for the confusion. A lot of viewers apparently thought Matsumoto was talking about the Reactor SFP like I did.
So, it was the Reactor 1 dry well temperature that started to rise noticeably starting 4AM on April 13, 2012.
No word yet on exactly what the temperature is in the Reactor 4 SFP.
—————–END OF UPDATE————–
According to Matsumoto [Tepco spokesman], the temperature of the Reactor 4 Spent Fuel Pool started to rise noticeably starting 4AM April 13, 2012.
From 8PM on April 12, 2012 to 3AM on April 13, 2012, the temperature remained 49.9 degrees Celsius, he said.
Matsumoto didn’t say what the temperature was at the time of the press conference (11AM on April 13) [...]
Title: SFP4 over 55°C. Coolant system is still stopped
Source: Fukushima Diary
Date: Apr. 12, 2012
Though Tepco stopped the water leakage, coolant system is still not back on. At the moment, they can’t estimate when they can recover it. Also, they estimated the temperature increases at 0.5°C/h, it’s increasing at over 1°C/h. It went up by 22°C within 18 hours. Currently the temperature of SFP is 55°C.(10:00 JST) The safety limit is 65°C. At this pace, it will reach 65°C about in 10 hours. [...]
…Developing…
See also: Kyodo: Possible Leak at Unit No. 4 -- Spent fuel pool cooling system halted after alarm sounds
Published: April 13th, 2012 at 2:52 am ET
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This doesn't sound good. What happens if it reaches 65 degrees?
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Bubble bubble bubble…TEPCO you got some serious trouble! When those spent rods hit 65 degrees they begin to release fission products from the zirconium cladding. The lower temperature isotopes react with the atmosphere and change they hydrogen levels, oxygen levels, xenon levels, ect. Then comes the fun if the temperature continues to rise it is another out of control fission event. One of many that have happened, been covered up, and is now blowing up in their face again. If you thought the first explosions bad wait till this open pool hits atmosphere in 15 hours when there is no cooling due to high radiation levels where no one can get close enough to stop it. BUT THEY HAVE IT UNDER CONTROL.
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At 65C, they have to retract the cold shutdown condition.
If it doesn't get too much hotter, then not a real big deal. But if it gets hotter, then the fan better duck.
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Fukushima diary piece has the video of Matsumoto at the press conference (done by lWB and our friend Yasumi Iwakami). There is no translation yet, but Yasumi usually gets translations quickly. So anyone who understands Japanese may want to go there.
Regardless, it does not look good.
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These figures are wrong. TEPCO stated that on 12-04-2012 at 14.44 (Japan) SFP4 was 28 celcius. By 12-04-2012 at 20.00 (Japan) the temperature had risen to 49.9 celcius. Thats a rise of 4.2 celcius per hour. Then out of the blue, without the cooling being restored, the temperature stops rising for seven hours.
Using their numbers by 11.00 on the 13th (Friday 13th) the temperature should be 10 celcius over boiling.
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50 celsius is already 122 farenheit. One would have to reach 100 celsius to reach the boiling point of water, 212 farenheit.
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Some important pic and diatribes,.
http://gyldengrisgaard.dk/fuku_docs/sfp4_rack22.jpg
From:
http://www.physicsforums.com/showthread.php?t=480200&page=801
I would add that this has been my amateur theory for some time now.
Scale, particles, and so on behave as insulators.
Relentlessly.
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Your quite right about the collected dust and slime being an insulator. By now there is probably 300mm to 900mm (12 to 36 inch) in the bottom of SFP3 and SFP4.
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I remember readin some months ago in a postor's comment that the purity level of the cooling water must be very high. It was in relation to the turbidity that had rapidly occurred in SFP4 around the time that the ROV had photographed inside the SFP. It revealed that there was a steel staircase and some concrete debris in the pool, as well as showing damage to some of fuel rod assembly racks which would make it very difficult to remove them without some human proximity (impossible because of radiation levels?).
Does anyone have any references to the interaction between radionuclides and other impurities or particles in cooling water? I remember that this was the main concern of the scientist who deduced that pumping in 7-9 tonnes of seawater per hour had created 'super soluble Buckey Ball structures' that gave radionuclides a more prolific migratory potential. See:
Links on water purity in cooling pools:
IMPACTS OF COOLING WATER QUALITY ON OPERATIONAL
SAFETY OF WATER COOLED REACTOR
http://www.iwtc.info/2007_pdf/13-6.pdf
"Cooling water chemistry and its effects on fuel elements cladding and reactor
components materials performance are important factors for safe and reliable operation
of nuclear reactors. This is because; at elevated temperature, water is an aggressive
medium and may causes corrosion problems in fuel elements cladding and reactor
structural materials. For this reason, reliability and safety for nuclear power and
research reactors are…
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(cont…)achieved by using proper fuel cladding and structural materials.
Also, cooling water regimes must be adjusted and proved to prevent dangerous
corrosion problems."
"Water quality is tightly controlled to prevent the fuel or its cladding from degrading"
http://en.wikipedia.org/wiki/Spent_fuel_pool
Bucky Ball Hell:
http://enenews.com/just-in-peroxides-formed-by-seawater-and-melted-fuel-even-more-likely-to-react-with-elements-in-core-not-clear-exactly-what-kinds-of-chemicals-were-released-different-than-freshwater/comment-page-1
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