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World’s First Thorium Reactor Designed

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Re: World’s First Thorium Reactor Designed

#21

Post by luckyno13 »

madaxe_again wrote: post #17
cstross wrote: post #5

Earlier quoted context omitted.

Note that you can breed U-233 from thorium and use that in nuclear weapons. The critical mass of U-233 is about 50% higher than Pu-239 but otherwise it's usable in implosion-type bomb designs; the main hazard is the presence of U-232 as a contaminant (which is a high level gamma emitter and makes it dangerous to work with) -- the real question is how they plan to reduce the U-232 contamination level enough to make we…

I don't understand the whole "it has to be capable of making bombs to be viable" thing. I mean, the local coal power plant can't make artillery shells, but we're not shutting it down...

Only an assumption here, but I would say its due to what to do with the waste. If the waste is useless, then we have to have a place to put it. If it has another use, then obviously we dont have to stick it in a hole somewhere.

Again, totally non-researched, off the top of my head assumption.

Re: World’s First Thorium Reactor Designed

#22

Post by rwcarlsen »

beedogs wrote: post #14
Aardwolf wrote: post #9

Nice specs! Where does the Thorium come from and how abundant is it?

"Thorium is three times more abundant in nature than uranium. All but a trace of the world’s thorium exists as the useful isotope, which means it does not require enrichment. Thorium-based reactors are safer because the reaction can easily be stopped and because the operation does not have to take place under extreme pressures. Compared to uranium reactors, thorium reactors produce far less waste and the waste that i…

Thorium is not a fissile isotope - meaning it can't be used for fission directly. It needs to be transmuted by neutrons into uranium 233 (which is fissile). By this measure, thorium isn't any better than Uranium 238 - which is 99.3% of naturally occurring uranium. So "All but a trace of the world's thorium exists as the useful isotope" - can be applied to uranium also. Uranium 238 is also a fertile isotope - and doing a completely fair comparison, uranium doesn't need to be enriched either... Except the only way we have to convert fertile isotopes to fissile isotopes is to expose them to a sustained, high neutron flux which is typically only economically achievable using enriched uranium (via the naturally occuring U235 isotope). Thorium breeder reactors need enriched uranium as much as uranium breeder reactors. So while thorium has some advantages, I wouldn't say that natural abundance or supply are particularly significant.

[Edit] corrected use of "fissile" -> "fertile"

Re: World’s First Thorium Reactor Designed

#23

Post by rwcarlsen »

eloff wrote: post #20
orbifold wrote: post #15

Earlier quoted context omitted.

Roughly 3-4 times as abundant as Uranium, according to http://www-pub.iaea.org/MTCD/publications/PDF/TE_1450_web.pd... . To give you an idea on how much energy could be produced with this: A rough estimate shows that if all our current electric energy demand would be satisfied with Uranium, the reserves would run out in roughly 10 years. See http://johncarlosbaez.wordpress.com/2010/09/03/how-long-woul... .

This estimate doesn't seem to account for enrichment. For every KG of uranium mined, you get a much lower ratio of enriched fuel.

It shouldn't account for enrichment because thorium is a fertile material (not fissile) just like uranium 238 (99.3% of all uranium). Unenrichced uranium can be used in breeder type reactors just like unenriched thorium.

Re: World’s First Thorium Reactor Designed

#25

Post by warfangle »

Gravityloss wrote: post #4

Note that this very different to the molten salt LFTR design. With solid fuel it is very hard to prevent protactinium capturing neutrons, which means problems for breeding and waste and probably operational constraints as well. The LFTR is such a beautiful consistent design but it is very different from ordinary reactors. Also the title is inaccurate as different thorium reactors have been designed, built and operate…

The big problem with a molten salt LFTR is the materials necessary for the plumbing. Any metal will become brittle as it is exposed to the radiation emitted from the reactor core. And manufacturing ceramics into the precision pieces called for is not a solved problem.

LFTR designs are fantastic, amazing, and solve a lot of problems. There is a lot of materials science to be done to make them viable, though.

Re: World’s First Thorium Reactor Designed

#26

Post by Tuna-Fish »

orbifold wrote: post #15
Aardwolf wrote: post #9

Nice specs! Where does the Thorium come from and how abundant is it?

Roughly 3-4 times as abundant as Uranium, according to http://www-pub.iaea.org/MTCD/publications/PDF/TE_1450_web.pd... . To give you an idea on how much energy could be produced with this: A rough estimate shows that if all our current electric energy demand would be satisfied with Uranium, the reserves would run out in roughly 10 years. See http://johncarlosbaez.wordpress.com/2010/09/03/how-long-woul... .

> rough estimate shows that if all our current electric energy demand would be satisfied with Uranium, the reserves would run out in roughly 10 years.

While strictly correct, this is extremely misleading. Current resources would be exhausted in a decade, but resources are defined as the known deposits extractable under current market prices. Should we actually start using a lot of uranium, the price would spike, which would lead to a lot more deposits becoming economically available. This has almost no effect on the cost of nuclear power, as the cost of the raw uranium isn't a large part of the cost of producing power.

The end game there is when the price rises sufficiently for extraction from seawater becoming profitable. The world's seas have ~1000 times more uranium than conventional ground-based resources.

Nuclear fuels will not run out in this millennium.

Re: World’s First Thorium Reactor Designed

#27

Post by Tloewald »

madaxe_again wrote: post #18
Rapzid wrote: post #11

Earlier quoted context omitted.

In certain parts of the world, maybe. In other parts differences in religion is the driving force behind conflict..

Disagree. Religion is the vehicle. Inequality is the driver.

There were/are religious conflicts in communities where it's impossible to tell the belligerents apart -- ethnically, economically, you name it.

"For every complex problem there is an answer that is clear, simple, and wrong."

Inequality is definitely a contributing factor, perhaps even _the_ contributing factor, but don't count out religion.

Re: World’s First Thorium Reactor Designed

#28

Post by DennisP »

orbifold wrote: post #15
Aardwolf wrote: post #9

Nice specs! Where does the Thorium come from and how abundant is it?

Roughly 3-4 times as abundant as Uranium, according to http://www-pub.iaea.org/MTCD/publications/PDF/TE_1450_web.pd... . To give you an idea on how much energy could be produced with this: A rough estimate shows that if all our current electric energy demand would be satisfied with Uranium, the reserves would run out in roughly 10 years. See http://johncarlosbaez.wordpress.com/2010/09/03/how-long-woul... .

That estimate for uranium assumes conventional reactors, which fission U-235. That's 0.7% of natural uranium.

For a real comparison, you should look at fast reactors, which use the rest of the uranium. That takes your estimate up to about a thousand years. But the estimate is looking at economically recoverable reserves, and if the same ore produces a hundred times as much energy, a lot more becomes economically recoverable.

Thorium would be 3-4 times more abundant than that. (But if seawater extraction works out, uranium will have the advantage again.)

Re: World’s First Thorium Reactor Designed

#30

Post by venomsnake »

Tuna-Fish wrote: post #26
orbifold wrote: post #15

Earlier quoted context omitted.

Roughly 3-4 times as abundant as Uranium, according to http://www-pub.iaea.org/MTCD/publications/PDF/TE_1450_web.pd... . To give you an idea on how much energy could be produced with this: A rough estimate shows that if all our current electric energy demand would be satisfied with Uranium, the reserves would run out in roughly 10 years. See http://johncarlosbaez.wordpress.com/2010/09/03/how-long-woul... .

> rough estimate shows that if all our current electric energy demand would be satisfied with Uranium, the reserves would run out in roughly 10 years. While strictly correct, this is extremely misleading. Current resources would be exhausted in a decade, but resources are defined as the known deposits extractable under current market prices. Should we actually start using a lot of uranium, the price would spike, whic…

How about energy return on energy investment. You have to vaporize a lot of water (of course you will have all those gold, iron, rare metals "waste" which will help the economic case).
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