Energy From Thorium Discussion Forum

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PostPosted: Oct 03, 2011 12:36 pm 
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Cyril R wrote:
But any major repairs or replacement of entire modules will be infrequent and we'll just drain the buffer salt to a lower level by pumping it up to an insulated tank outside containment.


I would guess it would be better to keep the fuel salt, blanket salt, and pool salt always within your containment. So yes pump them out of their normal locations but into holding tanks within the containment. This will allow some service actions that do not otherwise require breaking the containment to happen without breaking the containment.


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PostPosted: Oct 03, 2011 12:44 pm 
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Lars wrote:
Cyril R wrote:
But any major repairs or replacement of entire modules will be infrequent and we'll just drain the buffer salt to a lower level by pumping it up to an insulated tank outside containment.


I would guess it would be better to keep the fuel salt, blanket salt, and pool salt always within your containment. So yes pump them out of their normal locations but into holding tanks within the containment. This will allow some service actions that do not otherwise require breaking the containment to happen without breaking the containment.


For fuel and blanket salts that would be logical. But the buffer salt is a lot of salt. This increases the size of the containment.

I think the fuel and blanket salt can be contained in an in-pool storage tank when needed. A flush salt tank would also be in-pool. But putting >1 million liters of buffer salt somewhere in the containment?


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PostPosted: Oct 03, 2011 1:08 pm 
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If the buffer salt doesn't stay inside the containment then doesn't that move the legal fission product barrier to between the blanket and buffer salt?

Another possibility would be to lift everything up above the buffer salt (after the blanket and fuel salts are pumped out first). In some ways this might partially happen simply from the boyancy of the reactor when the fuel/blanket/secondary salts are unloaded.


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PostPosted: Oct 03, 2011 2:07 pm 
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Lars wrote:
If the buffer salt doesn't stay inside the containment then doesn't that move the legal fission product barrier to between the blanket and buffer salt?.


That's why not all the salt will be pumped out. A layer will remain over the temporary fuel and blanket salt storage tanks for cooling and shielding. These tanks would therefore be quite flat and the reactor and HX positioned slightly higher.

Lars wrote:
Another possibility would be to lift everything up above the buffer salt (after the blanket and fuel salts are pumped out first). In some ways this might partially happen simply from the boyancy of the reactor when the fuel/blanket/secondary salts are unloaded.


This has some advantages. We wouldn't have to pump out the buffer salt at all. However lifting everything back as an entire connected system will be hard, and if they are connected in place the buffer salt will be more likely to go in the primary. But perhaps we'll just be able to flush it again well before starting up, with the flush salt (traces of KF and ZrF4 is not a problem but we must be careful not to allow too much in).


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PostPosted: Oct 03, 2011 8:52 pm 
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Cyril R wrote:
Regarding inspection, Luke suggested to use glass fibers looking at the pool routing the light to a camera outside containment. Transmit light, but not heat and radiation.
Does glass get fogged by radiation damage? I hadn't thought about that when I made the suggestion.


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PostPosted: Oct 04, 2011 3:10 am 
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Luke wrote:
Cyril R wrote:
Regarding inspection, Luke suggested to use glass fibers looking at the pool routing the light to a camera outside containment. Transmit light, but not heat and radiation.
Does glass get fogged by radiation damage? I hadn't thought about that when I made the suggestion.


Hot cells often use lead glass for viewed shielding. I never read about how long those last but am guessing pretty long.

There are also, certain green zircons that had extensive decay lattice damage from internal uranium and thorium. They became completely amorphous, but are still transparent. Glass is already amorphous.

But perhaps it won't be such an issue for the pool design since the pool shields all gamma radiation and neutronic protection around the HX and vessel don't allow many neutrons in the pool. A small amount of activation of buffer salt would occur through the PRACS bypass flow and there would be some diffused tritium. Should be quite acceptable to glass fibers and robots, even for humans with rad suits (in fact the high temp in the hot cell should be a far bigger problem for humans than the ionizing radiation).


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PostPosted: Aug 03, 2016 12:32 pm 
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I know this is a very late post, but perhaps the sparge could use the waste Xenon 135?
Xenon adsorbs very well, and should stick to itself at least as well as helium does.
It should also help extract metal smokes.
It minimizes the waste volume, (i.e. the original problem.)
The CS137 waste product might remain in the salt, or be decayed and extracted,
depending on the out-of-circulation volume of the sparge loop
The equipment is complicated only by using a radioactive sparge gas.
The piping may be simpler (one gas, not two).
There's no continuing expenditure on Helium.
The initial sparge could be started with argon, perhaps.


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PostPosted: Aug 05, 2016 2:46 pm 
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Have a column at the top of the reactor that runs the fuel salt thru a metal sponge to remove the nobel metals and that reaches near vacuum pressure at the top. Vacuum draws off dissolved gasses too. Then the salt goes down the column to a pump at the bottom.

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