Energy From Thorium Discussion Forum

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PostPosted: Jan 04, 2007 7:56 pm 
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I've updated some of my slide package comparing the relative resource requirements of uranium-fueled light-water reactors to thorium-fueled liquid-fluoride reactors. Take a look and let me know if I got something really wrong. I used the "WISE Uranium" website for the LWR fuel cycle calculations, and used ORNL/TM-6474 for inputs about thorium mining, milling, and refining.

Uranium vs. Thorium comparison


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PostPosted: Jan 04, 2007 10:43 pm 
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Its interesting that, apparently, there are no high-concentration thorium ore bodies anywhere in the world.
At the same time, a good deal of the world supply of uranium comes from the mines in Saskatchewan, with ore concentration close to 20% (instead of the 0.2% in your ppt slides).
So it seems that Th reactors will only become more attractive economically - from the fuel cost point of view - when these high-grade ores are depleted (there are many U mines with lower-grade ores, but their pricing is currently limited by the producers with high-grade ores).

India was in a different situation.
With only limited U ore reserves, and external supplies cut off by boycots stemming from antiproliferation policies, India saw a need to develop thorium reactors -- if only to save their limited U stocks for military purposes.

But with the change in international policies spearheaded by the Bush administration, India will once again have access to the global U market.

Some people are betting that this will have an effect on India's R&D program, with a likely reduction in the priority of the thorium program.
It will likely advance to the "second stage," with (solid) thorium-fueled heavy water reactors (AHWR), but nothing beyond that any time soon.


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PostPosted: Jan 05, 2007 12:01 am 
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20% ore bodies? Wow, that's pretty good. Yeah, I wouldn't expect to find a 20% thorium ore body. But you need so little of it that 0.5% is plenty good.

And for the foreseeable future, the best thorium mine in the world will be found under about 20 feet of dirt in the Nevada desert...pure thorium nitrate in barrels!

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 Post subject: burn up in presentation
PostPosted: Jan 05, 2007 9:02 pm 
Understand your desire to beat up on urnanium based LWRs but your burn up number is a little low. Areva claims 70KGW/ton for the EPR.


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PostPosted: Jan 05, 2007 9:43 pm 
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Bill, I'm really not trying to beat up on LWRs. Believe me, I'm not. The numbers I put in there are pretty representative of the average performance of today's LWRs. I could bump them up but it wouldn't lead to a radically different conclusion.


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PostPosted: Jan 09, 2007 6:35 pm 
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A question posted on Know-Nukes at
http://tech.groups.yahoo.com/group/Know_Nukes/message/18649
Was answered here :
http://tech.groups.yahoo.com/group/Know_Nukes/message/18650


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PostPosted: Oct 15, 2011 2:26 pm 
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Kirk some time ago put together a nice presentation that compared Uranium vs. Thorium from the standpoint of energy sustainability.


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File comment: A very nice and concise comparison Kirk put together comparing Uranium vs. Thorium
thoriumVsUranium1.pdf [387.58 KiB]
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PostPosted: Oct 15, 2011 3:12 pm 
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To answer the question of updated LWR figures: with lower tails enrichment, a modern large 38% efficient subcritical steam turbine, and twice Kirk's burnup, you get down to about 150 MT U with a PWR and 100 MT U with a CANDU (slightly enriched uranium). Interestingly increasing the burnup for PWRs doesn't help in reducing the mined U required much (<10%) since you need to put in more neutron poisons to compensate for the higher fissile startup load. Improved enrichment is the biggest help (25%), whereas improved thermal to electric efficiency is only moderately useful (15%).

With the 0.8 MT Th bumped down a bit to take into account a slightly less efficient power cycle and some thorium losses in processing it gets to 1 MT Th. So even with these figures with optimized PWR and CANDU you still get 100-150x less actinide consumption for the LFTR.


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PostPosted: Oct 15, 2011 4:29 pm 
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I would consider the depleted uranium from enrichment in a very different class from spent fuel uranium as far as waste goes. Still a LFTR with full recycle is going to produce much less waste than an LWR. Our very first LFTRs may not be so good as the first LFTRs likely will not include full recycle simply to reduce the upfront R&D costs.


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PostPosted: Oct 15, 2011 4:56 pm 
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Overall I think that this is a good comparison and the full-recycle systems will always beat a once through system (LWR) because of the higher conversion rate. Similar diagrams can be made for full recycle fast reactors based on the uranium fuel cycle (significantly better resource utilization and lower waste than once through LWRs). The resource utilization for current LWRs at current enrichments and burn ups is between 180 and 200 MTU/GWe-yr.

We have yet to design an MSR than can fission all of the thorium. The MSBR designs discarded thorium after a period of about 10 years as a economics choice between a more complex salt processing system to perform difficult separations and to just discard cheap thorium as well as a desire to have an optimal breeding system. At the time, however, the waste thorium was not considered to be an issue, something that would be more of an issue now. Analysis of the MSBR designs show that the thorium utilization was about 11 MT/GWe-yr. Given the current emphasis on minimizing waste, I am certain that this number can be reduced, perhaps significantly.


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PostPosted: Oct 15, 2011 8:57 pm 
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Kirk Sorensen wrote:
I've updated some of my slide package comparing the relative resource requirements of uranium-fueled light-water reactors to thorium-fueled liquid-fluoride reactors. Take a look and let me know if I got something really wrong. I used the "WISE Uranium" website for the LWR fuel cycle calculations, and used ORNL/TM-6474 for inputs about thorium mining, milling, and refining.

Uranium vs. Thorium comparison

I get a 404 Error.


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