Sunday, April 8, 2012

David LeBlanc gives a brief account of the Molten Fluoride Salt family of Reactors @ TEAC3

Davod Leblanc is a brilliant Molten Salt Reactor researcher from Canada. Here he gives an account of not only LFTRs, but of U-235 fueled Molten Salt converters UMSRs. As I have previously indicated the UMSR can be a first step to the LFTR Dr. LeBlanc points to the DMSR as a simple reactor that uses already tested technology. It has all the advantages of a Molten Salt Reactor including superior safety features, and transuranium nuclear waste disposal, as well as a very high level of proliferation resistance. The DMSR is an UMSR that will be powered mainly by U-235, although some plutonium and U-233 can contribute energy. The a good case can be made that the DMSR can be built at a considerably lower price than Light Water Reactors.

Anti-nuclear Greens should love the DMSR because it provides answers to all of their objections tp nuclear power. But the anti-nuclear crowd, will not listen to David LeBlanc's report on the the desirable qualities of the DMSR because their objection to nuclear power is not grpinded on rational belief, opposition to nuclear power is based on and spread by an irrational fear of nuclear power. The opponants of nuclear power don't want to believe in nuclear power. They refuse to listen to articulate advocates of nuclear power, accusing them of being paid by the nuclear industry for their advocacy. This of course is a huge lie but it helps anti-nuclear Greens sustain their irrational, fear driven beliefs about nuclear power.


Nathan2go said...

Dr. LeBlanc has posted a copy of a paper that describes these reactors in greater detail:

and the discussion thread is here:

The paper was presented in 2010 at a Canadian Nuclear Society conference and contains the shocking result that the DMSR uses only 28% as much lifetime Uranium ore as a LWR, without any reprocessing at all! It gets even better with reprocessing on 30 year batches.

Used alone, the DMSR is fuel efficient enough to use the in-exhaustible uranium in the sea. Coupled with IFRs, proliferation resistance would improve, the long-lived waste could be incinerated, and uranium requirements would be greatly reduced and enrichment could be eliminated.

EL said...

The French have looked at this and found a graphite moderated LFTR to have a slightly positive feedback coefficient:

This seems to contradict Le Blanc's claim to the contrary.

Marmot said...

Thanks for the ARXIV link, EL. Having read most of it "The Thorium Molten Salt Reactor :
Moving On from the MSBR" I see no contradiction with Dr. LeBlanc. The French observe both that one may build an MSR with a positive thermal reactivity, but also that one is not required to do so. One trade-off is decreased moderator lifetime, to about one or two years when operating in the negative feedback hard neutron spectrum. Makes a production design more interesting.

Anonymous said...

I left another comment but there may have been an account problem.

I wanted to address the important concern raised by EL above that a graphite LFTR (like the 1970 MSBR design) may have a reactivity problem. This is mild concern for a Single Fluid thorium breeder design with graphite but not for the DMSR design.

When ORNL studied designs they did admit that for the MSBR their calculations showed only a very slightly negative temperature coefficient (about -0.8 pcm/K). Recent French studies show it might be slightly positive. However when ORNL modeled the DMSR in 1979 then found a very strongly negative coefficient of -7.2 pmc/K so there is likely no chance that any minor calculations errors would drive this positive.

David LeBlanc

Charles Barton said...

Exewacting protactinium from the one MSBr was potentually a big headach as my father knew from experience. He clearly prefered the two fluid aproach. The two fluid approach avoided most of the problems. The one fluid approach works well with the DMSR.


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