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PostPosted: Sep 09, 2011 9:25 am 
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Hmm, ORNL was well into this:

http://energyfromthorium.com/pdf/ORNL-TM-3939.pdf


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PostPosted: Sep 09, 2011 7:24 pm 
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It all depends on whether your primary containment is the reactor vessel & PHT loop, or the Hot Cell:

In the former case, everything needs to be absolutely leak-tight -- meaning fancy bolted flange connections or, more likely, welds all over.

In the latter case, welds are NOT needed, and flange connections are only made to prevent gross spills of processfluid (salt) on the hot cell floor.

I much prefer the latter, as it separates the containment function from the process function -- i.e. divide & conquer.

Also, with less emphasis on totally leak-proof flanges, one can use the type with quick-release mechanisms, that are easily handled by robotics & remote manipulators: piece of cake to change-out worn or defective components.


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PostPosted: Sep 09, 2011 7:43 pm 
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So we would consider the whole hot cell as like the interior of the reactor vessel in an LWR and would need to either weld or massive bolting for the walls of the hot cell? I like the idea that we could separate these functions.


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PostPosted: Sep 10, 2011 4:23 am 
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Yes the hot cell as containment seems like a good idea. But if we use a pool type reactor with the vessel and HX and dump tank submerged in a pool of relatively clean (very clean for a robot) buffer salt, then there are some questions left on how to replace modules. If modules are replaced then buffer salt can go into the primary loop. I guess it can be drained after re-connecting the new modules and then flushed with the flush salt and hopefully that would be good enough.


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PostPosted: Sep 10, 2011 5:58 am 
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jaro wrote:
It all depends on whether your primary containment is the reactor vessel & PHT loop, or the Hot Cell:

In the former case, everything needs to be absolutely leak-tight -- meaning fancy bolted flange connections or, more likely, welds all over.

In the latter case, welds are NOT needed, and flange connections are only made to prevent gross spills of processfluid (salt) on the hot cell floor.

I much prefer the latter, as it separates the containment function from the process function -- i.e. divide & conquer.

Also, with less emphasis on totally leak-proof flanges, one can use the type with quick-release mechanisms, that are easily handled by robotics & remote manipulators: piece of cake to change-out worn or defective components.


I think we can extend this concept further. The hot cell, as a containment, can further seperate its functions of cooling+contaiment and shielding. For safety we'll use a double containment consisting of a fairly thin metal. The annulus between the containments can be used for radiative heat transfer passive cooling and will have an annulus cleanup system to remove any activity if that somehow makes its way through the first containment. Then on the other side of the second containment there could be passive cooling chimney loop, so that's where the high temperature stops; you could then have cheap concrete low temperature for gamma and neutron shielding (if it is a pool type reactor with a couple of meters of fluoride buffer salt on top of the reactor vessel there won't be that much need for shielding though). The shielding material does not have any requirement for leak-tightness, at all. Its simply a wall that is disconnected completely from the containment. The containment being light and thin will have excellent seismic resistance.

This would be similar to a dry cask storage scheme so the regulators should be accustomed to it. The annulus cleaning system is already used in the European Pressurized Reactor, and chimney cooling is also licenced already for the AP1000. So I think this concept should be the path of least resistance while offering superb protection and easy construction.


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