3 ms·

A similar idea was presented at a TED talk by a NASA engineer a while back. He was in charge of planning a nuclear reactor on the moon, and he said he got the i

A similar idea was presented at a TED talk by a NASA engineer a while back. He was in charge of planning a nuclear reactor on the moon, and he said he got the idea from a really old book. http://www.ted.com/talks/kirk_sorensen_thorium_an_alternative_nuclear_fuel.html http://www.ted.com/talks/kirk_sorensen_thorium_an_alternativ...

vxNsr 13y ago
This was the first thing I thought of when I saw this. Kirk was the first guy who introduced me to the idea that our current electrical generating plants are incredibly inefficient. Sadly, it seems no one (who is in a position to do anything about it) really cares. That could be because they know things we don't, or it could be because they're paid (as in they have no incentive) not to care.
VLM 13y ago
Thorium sucks as a fuel. There are a couple issues: 1) People use fuel type as the identifier but exclusively talk about reactor design WRT safety and economics and efficiency and all that. A 1960s uranium BWR will, in fact, suck, compared to a 2000s thorium exotic design. Both will also suck compared to a 2000s era uranium exotic design. There's a hilarious stack exchange on this topic WRT whenever you hear someone talk about fuel choice you can assume they know nothing about chemistry or physics and are actually talking about reactor design. There is some linkage of course. You need a fast reactor to breed U which pretty much means sodium coolant but you can breed Th with thermals which means a more controllable reactor, etc. 2) See #1 now WRT big scale system design issues. Existing system in the US is to not reprocess. Hmm if we switch fuel to Th we'll have to reprocess to do it at all. Well if we use Th we'll therefore have less waste. So what. If we reprocessed U we'd also have less waste. But we don't reprocess. So either Th isn't happening as an executive decision, or if it does happen the only way it can "win" if executive decision not to allow U reprocessing, so that the .gov (instead of .com) can select the winners and losers. 3) Lots of optimization of trees at the expense of the forest. So the cheapest part of running a reactor is the fuel, and you'd like to save fuel why switching to Th. Uh... OK. Well Th neutron economy in the core is awful, you don't get as many n as from U, so you have to "make up for losses". No problemo, if too many n are eaten by structure, just use less structure, make it weaker, thinner, shorter lifespan, not as strong. Whoops you've now optimized the cheapest part, the fuel, to be a bit cheaper, at the cost of ballooning the four most expensive parts of running a reactor, that being building costs, design/approval, maintenance, and disaster recovery. Doomed. Just doomed. 4) There are proliferation issues with Th that are "somewhat" worse than the U system. Not insurmountable, just twice the work and headache. In this way its like switching from imperial measurements to metric. In theory as small long term gain, but the short to medium term PITA makes it never happen. Slow evolution, maybe, maybe not. Revolutionary leap forward, um, no, not gonna happen.
- DennisP 13y ago
  As David LeBlanc says, come for the thorium, stay for the reactor. There are a few solid-fuel thorium reactors and they're nothing special. What Sorenson is really talking about is a liquid-fueled reactor, which has a number of advantages. You can also build a liquid-fueled uranium reactor, which is exactly what LeBlanc is attempting in Canada. Regarding your second point, there's no traditional reprocessing with this reactor when using thorium. You start it with fissile fuel, then simply keep adding thorium, which is converted to U233 inside the reactor.
- guard-of-terra 13y ago
  2012 called, telling you everyone else has already switched from lame measurements to metric and are actually very happy with no weird coefficients when converting units.

vxNsr 13y ago

This was the first thing I thought of when I saw this. Kirk was the first guy who introduced me to the idea that our current electrical generating plants are incredibly inefficient. Sadly, it seems no one (who is in a position to do anything about it) really cares. That could be because they know things we don't, or it could be because they're paid (as in they have no incentive) not to care.

VLM 13y ago

Thorium sucks as a fuel. There are a couple issues: 1) People use fuel type as the identifier but exclusively talk about reactor design WRT safety and economics and efficiency and all that. A 1960s uranium BWR will, in fact, suck, compared to a 2000s thorium exotic design. Both will also suck compared to a 2000s era uranium exotic design. There's a hilarious stack exchange on this topic WRT whenever you hear someone talk about fuel choice you can assume they know nothing about chemistry or physics and are actually talking about reactor design. There is some linkage of course. You need a fast reactor to breed U which pretty much means sodium coolant but you can breed Th with thermals which means a more controllable reactor, etc. 2) See #1 now WRT big scale system design issues. Existing system in the US is to not reprocess. Hmm if we switch fuel to Th we'll have to reprocess to do it at all. Well if we use Th we'll therefore have less waste. So what. If we reprocessed U we'd also have less waste. But we don't reprocess. So either Th isn't happening as an executive decision, or if it does happen the only way it can "win" if executive decision not to allow U reprocessing, so that the .gov (instead of .com) can select the winners and losers. 3) Lots of optimization of trees at the expense of the forest. So the cheapest part of running a reactor is the fuel, and you'd like to save fuel why switching to Th. Uh... OK. Well Th neutron economy in the core is awful, you don't get as many n as from U, so you have to "make up for losses". No problemo, if too many n are eaten by structure, just use less structure, make it weaker, thinner, shorter lifespan, not as strong. Whoops you've now optimized the cheapest part, the fuel, to be a bit cheaper, at the cost of ballooning the four most expensive parts of running a reactor, that being building costs, design/approval, maintenance, and disaster recovery. Doomed. Just doomed. 4) There are proliferation issues with Th that are "somewhat" worse than the U system. Not insurmountable, just twice the work and headache. In this way its like switching from imperial measurements to metric. In theory as small long term gain, but the short to medium term PITA makes it never happen. Slow evolution, maybe, maybe not. Revolutionary leap forward, um, no, not gonna happen.

DennisP 13y ago
As David LeBlanc says, come for the thorium, stay for the reactor. There are a few solid-fuel thorium reactors and they're nothing special. What Sorenson is really talking about is a liquid-fueled reactor, which has a number of advantages. You can also build a liquid-fueled uranium reactor, which is exactly what LeBlanc is attempting in Canada. Regarding your second point, there's no traditional reprocessing with this reactor when using thorium. You start it with fissile fuel, then simply keep adding thorium, which is converted to U233 inside the reactor.
guard-of-terra 13y ago
2012 called, telling you everyone else has already switched from lame measurements to metric and are actually very happy with no weird coefficients when converting units.