Alternative Energy

[Lissa]

Thorium reactors create fissile material that can be used in bombs. People seem to think that using an LFTR you won't have to deal with neither waste nor fissile material that could be used in bombs, but people that believe this are deluding themselves.

LFTR are breeder reactors, the whole point of a breeder reactor is to make additional fissile material to continue the reaction as you convert fissionable material to fissile material and that you typically make more fissile material than you actually burn. Even still, as you create and burn more fissile material, you also start to get waste fission products that build up. Some of these waste fission products can shutdown the reaction. So periodically, you still have to seperate out the fissile and fissionable material from the waste fission products. While it takes much longer for LFTR, you still have to at some point.

When you do actually seperate the fissile and fissionable material back out, you can then gather material that could be used in weapons. The biggest thing I've heard for why someone wouldn't do that is due to the high amount radiation from the fission products, but the US, GB, France, SU/Russia, and China did exactly this in order to create their arsenals. This is why the various Non-Proliferation Treaties went into effect. Prior to the NPTs, the US use to rerprocess spent fuel and what was known then, but no one is willing to mention because of the NPTs, is that 99.5% of what comes out of a reactor each year is still usable in some way (95% as fuel, around 2% for industry, about 2.5% for medicinal) and only 0.5% of the actual material is waste that has a dangerous period of around 700 years (easily storable). But because of NPTs, we effectively toss 100% of what comes out of a reactor.

I've yet to see a single LFTR proponent be able to truly defend LFTR against standard Fission designs now. LFTR proponents seem to think that while the LFTR designs have been further iterated on to become safer and that standard LWR designs have been stuck in the 60s and 70s designs when in fact they too have been iterated upon (there were designs introduced the 90s that took acts of sabotage to have them meltdown due to the passive safety mechanisms built into the designs).

I think the main reason to consider thorium is due to its relative abundance compared to uranium. It is true current fission LWR designs have gone through all the design heavy lifting, and decades of safe operations.

Otherwise, I think we are on the same page...



http://fissilematerials.org/library/sgs09kang.pdf

I believe thorium fuels are more proliferation resistant compared to uranium-based fuels, due to the lack of plutonium production and in the danger of interim radioactive products. Not that a dedicated "state actor", like Iran or North Korea couldn't purify the u-233 to +99% weapons grade with a reprocessing cycle. The fuel is also not suitable for simple "gun" style bomb designs, but more suited to complex implosion designs.

Incorrect. Any fissile nucleus can be used in a nuclear weapon. U233 will work just as well as U235 (used in Little Boy) or Pu239 (used in Fatman) or Pu241. The difference is the amount of material needed for the "pit". In the case of U233, it creates more neutrons per fission than U235 or Pu239, thus you need even less U233 to create an adequate "pit".

Also, what people don't understand is the difference between a reactor and a weapon is critical density. A reactor and a weapon both contain at least a critical mass, but without a proper moderator (water in the case of LWR) or a specific density (implosion devices) neither will actually start a chain reaction. The other difference that comes with the critical density for a weapon is you end up in a super critical chain reaction (every neutron creates multiple neutrons from fission) unlike a reactor where you're dealing with a critical reaction (where one neutron creates only one neutron to slightly over one neutron to continue the process - I'm highly oversimplifying for brevity).

Also, seperating Uranium from Thorium is easy to do, so getting all that U233 from the Th232 is a simple chemical reaction. You don't need to a cetrifuge or the like (or in the case of the US and other highly advanced civilizations, lasers that can seperate U235 from U238 to near 95% enrichment in a single pass and get to almost 100% after just 3 or 4 passes).

Upside: If plutonium ever is used as the fissile component of thorium fuel, the plutonium is also thus efficiently consumed. The U-233 produced in thorium process is highly contaminated with U-232. U-232 has a short half-life (68.9 years), and is thusly more dangerous in the short term than U-238 isotopes.

Downside is also an Upside: The decay chain of U-232 in the fuel cell produces very dangerously penetrating gamma rays. Namly, thallium 208, who's decay emits 2.6 MeV gamma rays which are very energetic and highly penetrating. This makes handling "uncooled" fissile U-233 or reprocessed uranium contaminated with U-232 too dangerous. You'd be better off hustling bad actors for enriched uranium or plutonium materials.

Someone who wants it bad enough will still reprocess it. The other aspect that is not mentioned is that to create U232 from a (n,2n) reaction is rare. You're not going to build up a big enough concentration that even with a 70 year half life for the initial alpha decay of U232 down to Th228, it's going to be a while before you get down to Tl208.

{Note to FBI: in no way is Bolty responsible for the following }

So... suicidal maniac dirty bomb, well, yes maybe. For reference, fuel core is emitting 38 rem (or 380 mSv) /hr at 1 meter.

The rational building of a yielding nuclear bomb, not so much... Literally, any nasty lethal bio-chem in a conventional bomb would be as lethal, harder to detect, and easier to handle with latex gloves and a filter mask. It's in the same line as why Ebola is too lethal to be dangerous. You get it and die before you can spread it. Same here. If you got a pound of hot U-232, you'd be dead before, or soon after you finished making something with it. Exposure to 350 mSv was the criterion for relocating people after the Chernobyl accident, according to the World Nuclear Association.

Again, if someone wants it bad enough, they'll do it.

Getting a pound of U232 would necessitate a large reactor, most people are talking about 50 MW (at most) for LFTR. To give you an idea of relative size of a 50 MW reactor core, the TRIGA, a research reactor design used in a lot of places, had a cylindrical core that was about 6 feet in diameter and 2 feet in height with fuel rods that were also cylindrical and were 3 inches in diameter and 2 feet in length (about 90 fuel rods in total) and produced 2 MW of heat (with standard efficiency of 40%, that means that would be 0.8MW of electricity for that small amount of 20% enriched fuel). So, the LFTR "core" isn't going to be much bigger of liquid salt and thorium mixture.

Also, on the Ebola, the problem is that it doesn't incubate like the common cold. When you get the cold, when you finally get the symptoms, you've already had the virus running in your system for half a week or more. In the case of Ebola, the symptoms show up within a few hours of you contracting it, thus making it difficult to transport.