The Green Nuke - LFTR - Page 4
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Fiend13
Germany140 Posts
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Perdac Curall
242 Posts
On January 27 2012 19:10 Fiend13 wrote: Thanks for this really nice thread. If only all of them could be like that. Well thank YOU for the nice compliment! | ||
nekoconeco
Australia359 Posts
I guess the main issue is that someone has to be the first to pioneer the full-scale reactor. I am annoyed that Australia hasn't done more in the area (since according to some sources we have the largest Thorium reserves in the world). Either way once China has a successful reactor underway the argument for it will be much stronger. Especially if the environmental advantages can be quantitatively illustrated. | ||
gyth
657 Posts
On January 25 2012 10:27 Perdac Curall wrote: 4) LFTRs do not produce the "spent fuel" problem of ordinary solid fuel reactors like PWRs. Because the fuel is a liquid it can be fully burnt up in the reactor, so storage of spent fuel is not necessary. Something seems fishy with the neutron economy here. Normal nuclear fuel has to be replaced because some fission products are neutron absorbers and when more neutrons are absorbed than produced you lose criticality. Thorium is already a neutron down versus U-235. It has to undergo a neutron capture then decay to U-233 before it is fissile. (similar to the U-238 -> Pu-239 path) Furthermore the projected transuranic waste of a 40MW "mini" reactor produced over ten years is anticipated to be only a few millionths of a gram. This is teeny tiny amounts of pollution. That seem a very odd way to say that the reactor won't make any plutonium. There are still plenty of nasty products below 92. 9) unlike LMFBRs it does not use fast neutrons, it uses thermal neutrons, which makes fission much easier to achieve It needs thermal neutrons because thermal neutrons make fission easier to achieve, not because thermal neutrons are easier to produce. Fission produces fast neutrons, which turn into thermal neutrons as they slow down through collisions with a moderator. | ||
gyth
657 Posts
On January 26 2012 03:06 Perdac Curall wrote: The amount of energy in matter-antimatter reactions is 1000 times as energy dense as fusion, so it is not implausible that we can achieve a net energy gain there in the future It is implausible that energy wouldn't be conserved. It takes more energy to produce antimatter then you get from its annihilation. At best you would break even, but that'd need a world without thermodynamics. | ||
Perdac Curall
242 Posts
On January 28 2012 10:18 gyth wrote: Something seems fishy with the neutron economy here. Normal nuclear fuel has to be replaced because some fission products are neutron absorbers and when more neutrons are absorbed than produced you lose criticality. Thorium is already a neutron down versus U-235. It has to undergo a neutron capture then decay to U-233 before it is fissile. (similar to the U-238 -> Pu-239 path) That seem a very odd way to say that the reactor won't make any plutonium. There are still plenty of nasty products below 92. It needs thermal neutrons because thermal neutrons make fission easier to achieve, not because thermal neutrons are easier to produce. Fission produces fast neutrons, which turn into thermal neutrons as they slow down through collisions with a moderator. The fission of Uranium-233 produces on average 2.5 neutrons per fission, so it is above the required threshold of 2. Furthermore the worst neutron absorber, Xe-135, which is such a nuisance is solid fuel reactors, is not a problem at all in a LFTR, since it is a gas and just bubbles out of the liquid fuel. Here is a great talk by Kirk Sorensen on so-called "nuclear waste," most of which is just as valuable as the electricity produced. Yes thermal neutrons make fission easier to achieve, that is what was said in the post you quoted. The neutron cross-sections involved with thermal neutrons are so much bigger than with fast neutrons. | ||
gyth
657 Posts
On the bright side, it won't need control rods because it is barely delayed critical in the best case. | ||
Perdac Curall
242 Posts
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v3chr0
United States856 Posts
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DarKcS
Australia1237 Posts
.. It could happen. | ||
bobsire
Canada296 Posts
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Perdac Curall
242 Posts
On January 28 2012 16:08 v3chr0 wrote: I will leave this thread with a wealth of knowledge on the subject, great post, and great replys OP, really informative and has changed my opinion of Nuclear power in general, I would love to see energy technology adopt LFTR - it seems much more stable, abundant, efficient and cleaner. Comments like that make it all worthwhile. LFTR certainly caused me to re-examine my opinion on nuclear fission as well. | ||
ChriS-X
Malaysia1374 Posts
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Quantum314
England217 Posts
On January 26 2012 03:06 Perdac Curall wrote: There was a meeting back in 2004 on this very subject detailing the need for a dedicated antiproton facility in the US, but it was ignored by the Bush administration. The amount of energy in matter-antimatter reactions is 1000 times as energy dense as fusion, so it is not implausible that we can achieve a net energy gain there in the future (50-75 years from now when commercial fusion reactors are (hopefully) a reality.) http://arxiv.org/PS_cache/astro-ph/pdf/0410/0410511v1.pdf Yes, the 1000 times as energy dense is what lends it to being such an attractive idea for space travel as it saves so much weight. But it does not suggest that we could achieve a net energy gain. Fact is, because we do not have an antimatter mine anywhere we would have to make it ourselves. And due to the nature of matter-antimatter annihilation the best case scenario is that we get the same amount of energy out as we put in to make it, which isn't such an attractive property for a fuel. | ||
Perdac Curall
242 Posts
On January 28 2012 17:17 ChriS-X wrote: where does the flouride salt come from? http://en.wikipedia.org/wiki/FLiBe It is a commercially manufactured salt combination of Beryllium Fluoride and Lithium Fluoride. Flibe Energy, which is the only US company I know of pursuing LFTR, is named after it. | ||
Perdac Curall
242 Posts
On January 28 2012 17:22 QuAnTuM314 wrote: Yes, the 1000 times as energy dense is what lends it to being such an attractive idea for space travel as it saves so much weight. But it does not suggest that we could achieve a net energy gain. Fact is, because we do not have an antimatter mine anywhere we would have to make it ourselves. And due to the nature of matter-antimatter annihilation the best case scenario is that we get the same amount of energy out as we put in to make it, which isn't such an attractive property for a fuel. You may be right, but in 50-75 years I hope mankind can prove you wrong. | ||
CuddlyCuteKitten
Sweden2477 Posts
Seems like a decent idea but remember that toxic liquid fuels almost always get replaced with solid fuels because handling and maintnance never work out well. Simply put fluids leak and toxic leaks are bad. | ||
white_horse
1019 Posts
It does look like another too good to be true story but if it is really a viable method for nuclear energy, why the hell isn't the US government actively pursing the technology? Because mastering this would basically solve our entire energy problem. That the US government would pass this over and let china go after it alone would mean that we really have total dumbasses heading this country. | ||
3DGlaDOS
Germany607 Posts
On January 28 2012 20:00 white_horse wrote: Cool read, thanks. It does look like another too good to be true story but if it is really a viable method for nuclear energy, why the hell isn't the US government actively pursing the technology? Because mastering this would basically solve our entire energy problem. That the US government would pass this over and let china go after it alone would mean that we really have total dumbasses heading this country. German government then would be even more stupid since we waste a lot of money on solar energy subsidies. But people here freak out when they hear "nuclear power". | ||
enemy2010
Germany1972 Posts
I study energy ecomonics, and I personally thing this is the only way. | ||
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