Spent Nuclear Fuel Pools not dry in 4?

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  • #2
Astronuc
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I am just a finance guy, but I've been reading up on the current crisis and found this blog. Anyone here thing this guy might actually be correct in his assumptions?

http://atomicinsights.blogspot.com/2011/03/focus-on-food-water-shelter-dr-greg.html
The fuel rods however are not at pool temperature. They are a bit hotter. I think at 183°F, there is a fair amount of evaporation - from the top of the pool. If the rods are 30°F hotter, then steam can form on the surface. Those bubble rise up through the water and out into the air.

The author is not quite correct on the oxidation of UO2. UO2 is one form. U4O9 (O/U = 2.25) and U3O8 (O/U = 2.67) are higher order oxides. There is also UO3, which is water soluble, so one might be looking at hydroxides, but I don't think that should happen necessarily for UO2 in the SFP, and the other higher oxides are less likely at SFP conditions.

The issue is not the UO2 ceramic fuel per se, but the Zircaloy-2 (Zr-2) cladding surrounding the ceramic fuel. It is the cladding which retains the fission product, and is the first barrier between fission products and the environment.

The concern is that the Zr-2 cladding gets too hot and in contact with steam, or more so air (21% O), then the Zr-2 would oxidize/corrode to failure. Then the fuel rod would release fission products such as Xe, Kr, I, Cs, . . . .
 
  • #3
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Michio Kaku is suggesting for the PM to call in the Japanese Air Force to shoot cement, boric acid, etc. to entomb #4. Is this the final option and would it work?

 
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  • #4
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Michio Kaku is suggesting for the PM to call in the Japanese Air Force to shoot cement, boric acid, etc. to entomb #4. Is this the final option and would it work?

Dr. Kaku sounds like talking about a hypothetical in one of his science programs. His tone is so odd and nonchalant.
 
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  • #5
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Michio Kaku is suggesting for the PM to call in the Japanese Air Force to shoot cement, boric acid, etc. to entomb #4. Is this the final option and would it work?

It seems he is talking about a worst case scenario, but the problem is that kind of speculation is a direct result of TEPCO failing to provide current data about the situation.

P. S. He is only talking hypothetically. Just replayed the video and made it a point to listen carefully.

His comments also seem to drift from the affirmative (there are known containment leaks) to (if there are containment leaks). This suggests that his statement may have been taken out of context. He may have originally been talking about a hypothetical worst case scenario. And, I wouldn't jump to the conclusion that ABC deliberately showed his statement out of context, but the reporters involved may have jumped to that conclusion because such events are in many ways unthinkable.
 
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  • #6
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Tepco executives said Thursday that they believed the rods in that pool were covered with water, but an official with Japan's nuclear safety agency later expressed skepticism about that and moved closer to the U.S. position.

"Considering the amount of radiation released in the area, the fuel rods are more likely to be exposed than to be covered," Yuichi Sato said.

After the hearing on Wednesday, Jaczko left some wiggle room. If he is wrong, it would represent a very embarrassing moment for the U.S. government.

"My understanding is there is no water in the spent fuel pool," he said. "I hope my information is wrong. It's a terrible tragedy for Japan."

(from http://www.cbsnews.com/stories/2011/03/17/501364/main20044142.shtml?tag=cbsContent;cbsCarousel")

It is not quite clear whether the pool is dry. It looks as if part of the fuel may be dry. But if really all the water is gone already now, that must be due to some crack caused by the earthquake.
 
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  • #7
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Hi, I'm a novice here, however: has anyone suggested dropping compacted snow on these reactors from the helecopters to give them a better chance of delivering water on target?
 
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  • #8
Astronuc
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Hi, I'm a novice here, however: has anyone suggested dropping compacted snow on these reactors from the helecopters to give them a better chance of delivering water on target?
I doubt they are set up to do that. If the snow melted to a dense configuration, it might actually do damage due to impact. The idea is to cool without imposing large mechanical loads that might damage the fuel.
 
  • #9
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Originally Posted by Steveondo
Hi, I'm a novice here, however: has anyone suggested dropping compacted snow on these reactors from the helecopters to give them a better chance of delivering water on target?

I doubt they are set up to do that. If the snow melted to a dense configuration, it might actually do damage due to impact. The idea is to cool without imposing large mechanical loads that might damage the fuel.
__________________

I can see that impact damage could be a real problem, but may not necessarily be a problem if snow is not over compacted or could be winched down closer to the target.

I also think that there could be a method to deliver snow from a container suspended below a helecopter, ie. a 'concrete hopper' that could be winched as close as possible to delever to the target with more accuracy. Such a container may not hold the same quantity of less dense snow but if it hits the target each time in could get a result.

I don't know what the lifting capacity of the helecopters in use is, but a container (dare I say it, like a skip with a release mechanism to open doors or gradual realse) may work.

Just an idea. I hope that the situation is brought under control soon.
 

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