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PostPosted: Apr 30, 2009 11:27 am 
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Or perhaps they would want to redirect the funding toward a solution more politically palatable - like destroying the actinides altogether.


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PostPosted: Apr 30, 2009 11:38 am 
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Lars wrote:
Or perhaps they would want to redirect the funding toward a solution more politically palatable - like destroying the actinides altogether.


But that would mean shutting down LWRs altogether, because the longer you operate them the more TRUs you will generate. You'll always make more than you destroy even you attempt unlimited MOX recycle, which simply isn't feasible since trash nuclides build up.


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PostPosted: Apr 30, 2009 12:03 pm 
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And hence the need for LFTR! They can keep operating those LWR's that would cost $200B or so to replace if only they will fund a $10B development effort for LFTR.


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PostPosted: Apr 30, 2009 12:14 pm 
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This is also the economic fallacy of the GNEP approach--if you tell the utilities that every 2 or 3 LWRs will require a sodium-cooled fast burner along with its fuel reprocessing and fabrication costs, they'll just go ahead and say forget it and shut down the LWR.

LFTR is becoming more and more crucial to our energy future every day.


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PostPosted: Apr 30, 2009 12:20 pm 
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Do you think for starters we could do an LFTR actinide to u233 conversion machine?
One LFTR would absorb 25 reactor-years of LWR SNF for its startup charge and then consume 4 LWRs worth of SNF for continuing operations while producing around 1 tonne/year of u233.

Would it be acceptable to stockpile u233 for starting new reactors?


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PostPosted: May 01, 2009 3:47 am 
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I think our first goal should be a simple converter munching SNF, with a salt swap (hopefully) every 20 years or so. IMHO we should aim at something as simple as possible to begin with. Then a breeding blanket, then online reprocessing...


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PostPosted: May 01, 2009 9:24 am 
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Munching SNF means removing the Np, and Pu from the SNF to put into our reactor.
The simplest of this I think means a machine to mechanically breakdown the fuel assemblies, dissolving the fuel pellets in HF,
I suspect then we need to find a high volume way to remove most of the U,
then use our fluorinator to get the Np, and Pu out.

Even our simplest machine will need the He sparging system and a means to remove noble metals from the core.

With salt exchange and treating the old salt as spent fuel to be further processed in the future we can delay working on the liquid metal exchange system or the distiller.

If we don't have a blanket (I don' think this make the machine much simpler but it does help with proliferation concerns) we will need to add fissile regularly.
Perhaps I can try this over the weekend to see what it takes.

It would be tempting to replace the blanket with a graphite reflector to see what that does to the neutronics. This does introduce other challenges to solve though.
Bouncing thermal neutrons back through the wall will put more neutrons in the wall. When they reenter the core they will increase the fission rate near the wall which will also increase the neutrons flowing into the wall so one concern with adding a graphite blanket is the lifetime of the wall. A second concern is that the graphite will expand with neutron exposure and at a minimum that needs to be mechanically accomodated.


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PostPosted: May 01, 2009 2:27 pm 
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Lars wrote:
Munching SNF means removing the Np, and Pu from the SNF to put into our reactor.


Maybe a more direct way to get the starting load using existing infrastructure would be to first electro-refine the LWR fuel to get he heavy metal out. (PYRO-A)

There is a small scale pyro facility at INL which sould be enough for our initial small needs, and there are factories under construction in Korea and Russia.
http://world-nuclear.org/info/inf69.html


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PostPosted: May 01, 2009 6:12 pm 
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ondrejch wrote:
There is a small scale pyro facility at INL which sould be enough for our initial small needs, and there are factories under construction in Korea and Russia.
http://world-nuclear.org/info/inf69.html

The information at the cited link is very general -- I wouldn't rely on it for a near-term source of useable materials, produced using research-level technologies....


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PostPosted: May 01, 2009 7:21 pm 
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I guess to get the first prototype up & running, we should be fine with the prototype PYRO setup already existing at INL.


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PostPosted: May 01, 2009 7:27 pm 
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ondrejch wrote:
we should be fine with the prototype PYRO setup already existing at INL.

Are there any numbers available ? .....what have they produced ? ....composition & quantities ? ....was this a one-time thing, or are they still operating the "PYRO setup" ?


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PostPosted: May 01, 2009 10:55 pm 
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jaro wrote:
ondrejch wrote:
we should be fine with the prototype PYRO setup already existing at INL.

Are there any numbers available ? .....what have they produced ? ....composition & quantities ? ....was this a one-time thing, or are they still operating the "PYRO setup" ?


Good questions. Here is the status at 2007:
http://www.inl.gov/technicalpublication ... 931942.pdf
Quote:
At the end of May 2007, 830 and 2600 kilograms of driver and blanket fuel respectively have been processed since spent fuel operations began in June 1996



We need several t of fissile / GWth, for the epithermal/faster converter, right? To make a 10MWth test would need ~ 20 kg of fissile? (I dont know how it scales). However something in this range seems feasible even with their current small scale equipment.

Perhaps someone at the forum knows what is happening at INL?


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PostPosted: May 02, 2009 1:56 am 
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Isn't there around 500kg of u233 that the government would pay to get rid of?
Also, I believe France has stockpiles of Pu from reprocessed SNF.
I don't think startup fissile for an experimental prototype is a constraint.


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PostPosted: May 02, 2009 5:14 am 
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Lars wrote:
Isn't there around 500kg of u233 that the government would pay to get rid of?

In another thread, we were discussing how to STOP the government plan to downblend the U233 and dispose of it as waste : I haven't heard of any changes to that plan, to date.
Apparently, it would take an act of congress....


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PostPosted: May 02, 2009 5:21 am 
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Lars wrote:
Also, I believe France has stockpiles of Pu from reprocessed SNF.

Yes -- so do the UK and Japan : All three countries are much better set up for starting an MSR program than the US.
Moreover, importing separated Pu would be a highly politicized proposition, involving a great deal of expensive, high security (i.e. a "nightmare").


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