Published: November 6th, 2012 at 9:11 pm ET
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Title: Daily Report
Source: TEPCO : Press Release
Date: November 6, 2012
At 9:53 AM on November 6, Unit 3 spent fuel pool alternative cooling system was stopped in order to check the change of visibility inside the spent fuel pool (clarity of the pool) during system suspension as a preparation for debris removal from the pool (The pool water temperature when the system was stopped: 17.5℃). The system will be suspended until November 10. Since the pool water temperature increase rate is estimated to be approx. 0.17℃/h and there will be a sufficient margin to the maximum allowed temperature of 65℃, there will be no problem with the pool water temperature control.
Fukushima Daiichi Nuclear Power Station Plant Parameters as of 5:00 on November 7, 2012: Alternative cooling equipment of the Fuel Pool of Unit 3 is stopped. Therefore, Temperature in the spent fuel pool and FPC skimmer surge tank level of Unit 3 show close data. The expected temperature increase at the SFP water is around 0.166℃/h
Published: November 6th, 2012 at 9:11 pm ET
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sending...
and if theres an EQ during this time?
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' there will be no problem with the pool water temperature control.'
They are so sure about some things….. that makes me worried.
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Wonder what their back up plan is a bucket parade
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tea cups is the backup plan
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Lol but it is very sad and dire. What in the world is TEPCO doing I'm so disappointed at the snails pace of addressing the corium, SFP, etc. They were going to build a wall, they were going to build a new crane to remove Spent fuel at reactor 4 and the list continues. I don't mean to judge but I really don't see any progress since this accident happened. Perhaps I'm being to critical. ah
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Perhaps there is not much intact fuel left in unit 3's pool to cool?
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Non-intact needs cooling all the same, in fact more as it's more densely packed and less well protected. I'd say we'll find out from how fast it heats up, but I guess people won't believe whatever numbers they put forth.
It's far from the only time they're doing this though, you could say they have experience:
"At 3:30 PM on October 30, Unit 2 spent fuel pool alternative cooling system was stopped for a power cable improvement work (power supply to the system is terminated during the work) (The pool water temperature when the system was stopped: approx. 21.4℃). At 5:21 PM on November 2, the cooling was restarted as the power supply to the system was recovered (The pool water temperature when the system was restarted: approx. 30.6℃)."
Unit 2
Time delta: 3d + 1:51 = 73.85h
Temperatures delta: 30.6 – 21.4 = 9.2 degrees C
Delta t per h = 9.2 / 73.85 = 0.125 C/h
From http://fukushima.ans.org/inc/Fukushima_Appendix_G.pdf we get decay heat MWt in June 2011 as 0.52 and 0.46 for unit 2 and unit 3 respectively. Unit 3 SFP should actually heat *slower* than unit 2 due to less decay heat from assumed inventory, but I think this is mostly explained by Unit 3 SFP having had more "hot" fuel bundles which by now have cooled and the total number of fuel bundles dominates now. That, plus TEPCO's heat-up estimate for Unit 2 SFP was 0.22 C/h so either they reached 38 C instead, or they're including a safety margin. (Or, there's no fuel in Unit 2 SFP)
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Thanks for the data on unit 2 Guezilla
Why would unit 3's "hot" fuel be cooled by now?
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Not cooled, but cooler. But honestly, I think TEPCO is using safety margin of about 2X which is smart (even more might be warranted ofc). And for one thing they don't control the outside temperature, which is a big factor.
The cooling of irradiated nuclear fuel is dominated by the decay of high-activity isotopes along the decay-chain into non-radioactive or lower activity ones (and to much lesser degree by the fuel being "consumed" in the process).
An illustration of this transition can be found at http://www.world-nuclear.org/education/phys.htm about halfway down. Cesium-137 and Strontium-90 are the leading sources of radioactivity, but due to medium half-life they will fall to zero in thousand years (the axis are logarithmic, so in reality the initial fall-rate is much steeper).
http://www-ns.iaea.org/downloads/ni/embarking/argonne_workshop_2010/Braun/L.6.2%20Braun%20Operational%20Safety%20of%20Spent%20Nuclear%20Fuel.pdf (if the link comes out working…) is far too technical, but it gives the residual heat of fuel irradiated for 3 years:
Seconds after shutdown vs. fraction of full power
1 0.06247 (1 second)
10 0.04804 (10 seconds)
100 0.03115 (Minute and a half)
1000 0.01886 (15 minutes)
10000 0.009237 (3 hours)
100000 0.00487 (Day)
1000000 0.00247 (Two weeks)
10000000 0.000775 (Four months)
100000000 0.0000994 (Three years)
1000000000 0.00001736 (30 years)
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"…Non-intact needs cooling all the same…"
With the exception of the fuel pellets that rained down on the turbine building roof (my speculation – TEPCO never said much about where anything went). I wonder about the heat of a single fuel pellet outside of an assembly. If its not being irradiated from neighboring pellets, then maybe they're not terribly hot. I would think the turbine building roof would be steaming like crazy when it rained though. Unless they melted through the roof and are somewhere on the floor of the turbine building. Plenty of water there to cool individual pellets.
I suppose there's a possibility that the reactors exploded or melted down without somehow launching *any* fuel outside the building. Not counting the corium melting its way to Argentina, of course.
I'll email TEPCO. You know how those chatterboxes like to talk about their reactors.
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Individual fuel pellet might be more problematic, well sort of, the radiation is much less of course.
"It's geneally held in the industry" as certain document stated, and I believe it still is considered true, that after about 120 days of cooling spent fuel can be cooled through natural convection of hot air from the heating power alone.
The problem, of course, is that there will be no radiation shielding from the water so it's impossible to get anywhere near and the heat will be deforming the fuel and likely leading to major airborne release of radioactive isotopes, so this is absolutely not a desirable outcome.
Also the situation will be quite different in a crammed up cooing pool with only part of the rods exposed to contribute to convection, possibly huge amounts of debris blocking the rest and at worst case the rods crumpled in a pile in a corner instead so no convection can form but possibly transient criticalities.
In any case, in the case of a single fuel pellet natural convection can't really form either as there's not nearly enough vertical range. The heat will depend on the burnup and cooling "age" of the fuel as the above table. The oldest fuel is moved to the common pool, so it would probably still get quite hot, though radiation would be bigger problem. However I believe they bulldozed all radioactive debris under earth, so if there were fuel pellets they'd likely be there now like at Chernobyl.
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TEPCO was busy with little press releases yesterday, but from their daily situation report this little tidbit:
"At 2:09 PM on November 5, Unit 4 spent fuel pool alternative cooling system was stopped for adding anti-freeze liquid into the secondary system circulation water to prevent the water from freezing during winter time (The pool water temperature when the system was stopped: approx. 24.0°C). At 4:35 PM on November 6, cooling of the spent fuel pool was restarted after the work was completed and no problem was found with the system operation. Though the spent fuel pool water temperature increased from 24.0°C (temperature when the system was stopped) to 31.0°C, there is no problem with the pool water temperature control considering that there is a sufficient margin to the maximum allowed temperature (65°C)."
They've gone around doing this operation slowly on all the pools. 31.0-24.0 C / 26.43 h = 0.265 C/h. That's… hot, but we knew that. And they're still worried about freezing, but better safe than sorry (and why exactly does adding anti-freeze require over a days interruption?) Given same weather and starting temp, that's still 136 h (5.6 days) to their 60C limit and 287 h (12 days) to boiling. Assuming even temperature rise of course, which may be a big assumption. And assuming TEPCO's data is correct, but these pools have now been cooling for almost 2 years, so it looks believable.
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Maybe they are running out of money…
$50 BILLION, 50 Yr. Old Nuclear Corporate Welfare Program; via A Green Road
http://agreenroad.blogspot.com/2012/06/50-billion-50-yr-old-nuclear-corporate.html
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Total Fukushima Radiation Released Into Ocean, Air, Groundwater, Storage Tanks; via A Green Road http://agreenroad.blogspot.com/2012/02/total-fukushima-radiation-released-into.html
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+311.
Probably why they're not too worried with their crane fishing expeditions. Most of the pool contents sure looked like they either blew out with the supersonic explosion or burned up later with the countless days of fires at Unit 3. Most of the Unit 3 fuel contents blew up, vaporized, or burned up. Chunks may have been expelled from the big blast and were bulldozed into the lagoon or covered up with iron plates.
The biggest remaining emissions at Unit 3 may be fissile fuel splatter in the containment areas and possibly a sizable corium in the ground beneath Unit 3. How far down in the mudstone that MOX corium has burned is an interesting question. The runaway coriums at Units 1 and 2 are also subject to great speculation.
Perhaps we gave the nucleocrats too much credit in thinking they actually knew the location of the three missing piles of fissile fuel that melted down, melted through, and melted out of the manmade containments.
The movie Dumb and Dumber comes to mind when we look at their ineptness.
Unfortunately while a comedic movie is funny, a nuclear plant tragedy kills people and ruins land, air, water, and food forever.
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well said Sickputer….
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They KNOW!!!!
They would not be working so hard to keep the truth out, if they did NOT know.
They would have scientists in there and experts from around the world consulting with them, letting them do their stuff, if they had a SHRED of character, decency or ethics.
The FACT that they have a 20 mile NO GO zone in the ocean off FukU, and a no go zone for journalists and scientists all around the plant, speaks volumes…
No one is allowed to confirm the fact of one to three melted coriums. No is allowed to tell the truth about the explosion at #3 or talk about the 250 kilograms or more of nano sized plutonium released…
This is just the tip of a VERY DIRTY iceberg… The Titanic hit it, and that nuclear industry ship is now sinking with all hands on board.
They sunk the lifeboats that COULD HAVE saved the children of Japan.
They closed the hospitals and do not allow INTERNAL radiation testing.
They spot check food and DILUTE any high levels, which is meaningless when it comes to internal radiation exposure of one grain of high dose rice.
It is not innocent denial.. It is a cold, calculating, devious energy..
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Good point AGreenRoad
Evil walks in this world…
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Maybe it is just very unconscious, dark, and animalistic way of being, as opposed to living in the light, with love and compassion… resulting in a very high consciousness and awareness..
Wild animals can be very ruthless, cold and uncaring; eating their own young, their own kind, killing each other (hen pecking order), etc…
That does not make those animals evil.
Animals are however pretty low consciousness…. Add some intelligence and knowledge of nuke things to humans of this dark/dense ilk and you end up with a pretty dangerous wild critter running loose on the streets.
By their fruits you will know them.
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+1
Multiple points.
All correct.
(my opinion)
With time, the 'NO-GO' Zones will expand.
The current number of 'No-Go' zones on this planet is staggering. That number is not decreasing.
Here's list…
just some of THE WORST (known) 'No-Go' Zones:
http://www.viewpointonline.net/a-survey-of-the-worlds-radioactive-no-go-zones.html
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It is those 'no go zones ' that concern me the worst ChaAnn .
To think that mankind has ruined them for eons unknown …
Thanks for the link, as always dear
mission
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Only when I'm truly late for an appointment does my car decide to not start. I am not sure why that is? Fortunately, in the case of my car, there is "no immediate danger", just a lot of frustration.
I am hoping that when they restart the cooling system it doesn't act like my car and if it does, I pray they have car batteries and jumper cables. I'm pretty sure they have those. Maybe someone should check on that before hand?
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Everything will be fine, if needed they will just tie a garden hose to the cable hook on one of those tall cranes to fill the pool.
Disregard the runaway melted cores.
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It seems to be more important to keep the ice cream from melting in the office frig, than to bother with multiple melted 100 ton out of control nuclear fires underground.
Maybe duct taping the holes that the coriums left will work?
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Oh!!! Yea!!! Fun!!!
Another "Within limits" game.
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Channeling Or-Well, but…
As I wound up Daiichi stair,
I met a pool that wasn't there.
It wasn't there again today…
I wish that pool would go away.
Forgive me, I didn't get enough sleep last night, watching the election.
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LIKE!
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When fission takes place, say like in molten fuel blobs, the clock restarts on decay life and heat with the newly radioactive isotope elements created.
Woods Hole notes new daughter isotopes are still being created and showing up nearby in the ocean according to TEPCO's own monitoring readings. Something is still terribly wrong at Fukushima.
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From the TEPCO Daily Report, this time reading like poorly written poetry and raising more questions than it answers.
"At 9:53 AM on November 6, Unit 3 spent fuel pool alternative cooling system was stopped in order to check the change of visibility inside the spent fuel pool (clarity of the pool) during system suspension as a preparation for debris removal from the pool (The pool water temperature when the system was stopped: 17.5°C). At 4:33 PM on November 9, the system was restarted as the visibility check was completed (The pool water temperature when the system was stopped: 25.4°C). At around 5:00 PM on the same day, a TEPCO employee on patrol after the system was restarted found that the filtrate water used for cooling the secondary cooling system water was continuously dripping from the water tank (storing water to be sprinkled) above the secondary cooling system located outside. As a result of site investigation, the hole from where water is sprinkled out was found to be clogged. Dripping was stopped after cleaning the hole and the system was confirmed to be operating properly."
(25.4C – 17.5C) / 78.67 h = 0.100 C/h (assuming I counted right).
Unit 2: 0.125 C/h
Unit 3: 0.100 C/h
Unit 4: 0.265 C/h
Dependent on outside temperature, TEPCO telling the truth and other factors. Unit 4 SFP is practically full, with complete reactor core deposited into it shortly before accident, so this would be pretty much expected.
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