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What absorbs the neutrons then?
by bilsbie 11mo ago
What absorbs the neutrons then?
- lazide 11mo agoThe thorium cycle is generally neutron negative.
- JumpCrisscross 11mo ago> thorium cycle is generally neutron negative Source for the fuel cycle? Thorium 232 -> 233 is neutron negative. But after that you get all kinds of nonsense.
- lazide 11mo agoThorium 232 is the thorium in the cycle yes. And all kinds of nonsense is correct for the daughter products. But in general, to actually use do anything with thorium you need excess neutrons. Even the daughter uranium 233 only produces on average 2.48 neutrons per fission, so it’s very difficult even in a combined lifecycle process to have enough - thorium doesn’t produce uranium 233 immediately (takes almost 30 days), neutron capture with that low a ratio requires a LOT of thorium, which is going to mostly just suck up all neutrons and you won’t have any extra for addition uranium 233 fissions, etc. It’s quite difficult (impossible?)to have actually work without a source of a large amount of additional neutrons.
- JumpCrisscross 11mo ago> to actually use do anything with thorium you need excess neutrons Unless 100% of those neutrons is being absorbed by the thorium, this means you'll have neutron flux at the boundary. Which, for a liquid moderator, means all the pipes and tanks and pumps.
- lazide 11mo agoIt’s almost like there is a reason why it’s not commonly used despite all the hype.
- hunterpayne 11mo agoSure, if you ignore all the parts of the neutron economy that make it possible to work. The part everyone missed in this discussion is that all of the numbers of neutrons (and their barns) aren't constants. Since the fuel is a fluid, you can use density and shape to improve the neutron economy in the reactor core. Basically, when the atoms are closer together, the economy improves. You can also use a better moderator like graphite since the basic design is safer and the rate of fission is just easier to control. And considering that people made these things work 60 years ago without modern computers, the idea that its impossible or needs 40 years of research seems pretty far fetched. What is left of the nuclear industry wants to build current designs like the AP1400. That is a great idea, but there are things you can do with a LFTR that you can't do with an AP1400. The biggest of them is making synthetic fuel. The other advantages are the amount of waste produced and the fact that you can make a LFTR into a waste burner consuming the spent fuel rods from a AP1400. The downside is you actually have to fix nuclear regulations to do this and getting politicians to do that has proved impossible. There are no technological barriers, this is entirely political.
- deleted 11mo ago[deleted]
- JumpCrisscross 11mo ago> What is left of the nuclear industry wants to build current designs like the AP1400 That's just Westinghouse. There is a lot of research happening in small and medium-sized reactors. > There are no technological barriers, this is entirely political To thorium MSRs? The main barrier is economic.
- lazide 11mo agoNah, it’s just hard and silly - without a lot of payoff. When there are plenty of easier options for most nations. That you’re even discussing graphite moderated (?!!) makes this pretty clear.