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What makes uranium more economical, fuel production or some aspect of operation? And if it's the first one, is that just lack of scale for thorium or something

What makes uranium more economical, fuel production or some aspect of operation? And if it's the first one, is that just lack of scale for thorium or something else?

godelski 2y ago
Uranium is pretty abundant. The US has a lot, China twice as much, Kazakhstan a lot more, and Australia puts everyone to shame. Thorium isn't ready to be fuel and must be enriched (granted, you need to do this for uranium too but some is naturally in a fissile state). So there's things like breeder reactors that enrich during the cycle but this is challenging and presents other issues such as turning it into weapons manufacturing (increase proliferation concerns). There's a lot of small details that matter a lot. Fwiw, the parent has written a fair amount on this and runs a website with a lot of useful information for anyone curious. You can check their comments too as they usually participate anytime nuclear comes up https://whatisnuclear.com/thorium.html https://whatisnuclear.com/thorium.html
- AnthonyMouse 2y ago
  Isn't thorium also pretty abundant? Judging by this, the US has around six times as much thorium as uranium: https://en.wikipedia.org/wiki/List_of_countries_by_uranium_reserves https://en.wikipedia.org/wiki/List_of_countries_by_uranium_r... https://en.wikipedia.org/wiki/List_of_countries_by_thorium_resources https://en.wikipedia.org/wiki/List_of_countries_by_thorium_r... I've also never really gotten the proliferation concern. I mean, sure, you don't want to sell a breeder reactor to Iran. But why can't you sell one to PG&E? Are we that concerned that California could get the bomb? Plus, isn't the proliferation thing supposed to be one of the advantages of thorium, since you can't feasibly make a bomb out of the uranium-233 it gets bred into?
  - lazide 2y ago
    Yup. The big issue with Thorium is it isn’t fissile at first, and requires an existing nuclear reactor and careful fuel management to actually be usable in a reactor.
  - tim333 2y ago
    >A declassified 1966 memo from the US nuclear program stated that uranium-233 has been shown to be highly satisfactory as a weapons material (wikipedia https://en.wikipedia.org/wiki/Uranium-233#Weapon_material https://en.wikipedia.org/wiki/Uranium-233#Weapon_material)
    - AnthonyMouse 2y ago
      From the same article, apparently the infeasiblity is that pure uranium-233 could work, but a normal breeder reactor would also produce a small amount of uranium-232, which is fine for power reactors but not bombs. If you have the resources of the US DoD then you can design a special breeder reactor that uses special thorium, but by that point you could just make one that breeds plutonium out of uranium too.
      - credit_guy 2y ago
        Although in theory a U-233 bomb would work just fine, the fact is that very few U-233 bombs were ever made. I don't think that more than 10, by all the nuclear powers combined. One way or another U-233 is not as good a bomb-making material in practice as it is in theory.
  - godelski 2y ago
    > Isn't thorium also pretty abundant? Yes. Even more so! But that doesn't mean it's easy to get. Everything has to be processed at the end of the day. The reason I brought up uranium is that it is easier to fissile. So sure, there's more thorium but it requires more processing. Why use it when we aren't concerned about uranium access? Uranium is already "cheap". (We could get into an analogy with different types of oil if that helps. Like why the US produces so much, exports it, then buys a different type) > I've also never really gotten the proliferation concern. There's two issues here: 1) sure, the US doesn't care if California gets a bomb, but Russia and China sure do. 2) Breeder reactors are reactors that make higher elements. Discussion of thorium are often extremely over simplified. Proliferation always ALWAYS must involve international relationships. When we get into that the logic changes. You need to consider a lot of higher order effects/connections since everything is always being used as leverage for other things. Breeding is also a very complicated topic. Just like enrichment. Look at the Iran deal. They can do enrichment but only do much, right?[0]. Often fine because it's hard to scale and generally noticeable. But the same is true for breeding. Instead of turning one atom into a different isotope (e.g U238 -> U235) you change an atom to a different atom (e.g. Th233 -> Pa233 -> U233). This all happens in the reactor. It's hard to separate but hard to track. You can also keep breeding (fast reactor = more/high energy neutrons), where do you think plutonium comes from? The reason it is better for proliferation concerns is it increases the difficulty. At worst, you need to start earlier. But what I wanted to combat is the misinformation that thorium __can't __ be used for proliferation, making it safe for.., idk, Iran? It's good to add more barriers. I'll also add waste. This is often discussed too. This is again fraught with nuance. We can dramatically reduce waste but we don't. There just isn't much of it and doing more fission is less economical. That is, unless you don't have lots of uranium laying around. That's the case with France, so they "recycle" their waste and in the process this dramatically reduces it. You can fit over 50 years of waste in a Costco and they do. You also can use similar technologies as thorium would need with uranium and still reduce waste. So that points us back to the opening: yes, thorium is abundant, but why go through all that effort when we got plenty of uranium which is cheap and efficient? I recommend poking around AcidBurn's website. He has a lot of good information and I think he's written well in a way that's fairly approachable (it is nuclear, it's by default not approachable and easy to think you understand much more than you do. If you went through a physics degree this is often a confusing class taken at the upper level). [0] When they broke the agreement and made more they suspiciously only made a small amount more which would take a long time to get enough for weapons. But they were also loud. Great strategy because public gets afraid, it's a threat, but they also signal that they're willing you deal but want to renegotiate (only experts would know this though). The interesting part is how their best weapon was our own fear and ignorance.
- adrian_b 2y ago
  Thorium is more abundant than uranium and as said in the article China already has huge amounts of extracted thorium as a waste product from the extraction of rare-earth metals. Thorium must not be enriched and it cannot be enriched like uranium, because it has only one isotope with a long life, thorium 232, which is the only natural isotope. Natural thorium is not usable as a fission fuel, but it can be transformed into uranium 233, which is a fission fuel, by another nuclear reactor. The extraction of uranium 233 from thorium has nothing to do with uranium isotopic enrichment. It is a process orders of magnitude simpler, because it is just a normal separation of distinct chemical elements. This is actually the reason why thorium reactors have been avoided, because it has been considered that it is too easy to separate the uranium 233 from the fuel, which can be used for making nuclear weapons.
  - acidburnNSA 2y ago
    You're right that thorium can't be enriched because there's only one isotope. It needs to be bred to Uranium-233 to work. However, breeding has been more expensive and costly than enrichment, and this is the crux of why thorium use wasn't expanded in the past. To breed thorium to uranium-233, you need a breeder reactor, and you need a chemical separation facility. Together, these are more expensive to build and operate than a centrifuge and simpler non-breeder reactor. In this sense, I disagree that the process is orders of magnitude simpler. I'd argue that it's the opposite! The idea that thorium-derived material can't be easily used to make nuclear explosives is an unfortunately persistent myth. You can easily make very nice weapons material from thorium. As the Livermore weapons designers once said: "If today's weapons were based on U-233, [we] would have no interest in switching to plutonium" [1] [1] https://www.osti.gov/biblio/79078 https://www.osti.gov/biblio/79078
  - deleted 2y ago
    [deleted]
  - panick21_ 2y ago
    > This is actually the reason why thorium reactors have been avoided, because it has been considered that it is too easy to separate the uranium 233 from the fuel, which can be used for making nuclear weapons. This is absolutely not the reason thorium reactors have been avoided at all. The reality is that uranium enrichment infrastructure existed and fuel isn't a huge part of the cost. Most of the funding happened in the early days and they were of course using uranium, people back then figured that uranium would run out and were interested in breedres. But pretty quickly, uranium was found to be pretty common. Uranium is also just better unless you are doing a thorium thermal breeder. And that design only really works well with a pretty complex reactor setup that most people were simply not interested in.

What makes uranium more economical, fuel production or some aspect of operation? And if it's the first one, is that just lack of scale for thorium or something else?

godelski 2y ago

Uranium is pretty abundant. The US has a lot, China twice as much, Kazakhstan a lot more, and Australia puts everyone to shame. Thorium isn't ready to be fuel and must be enriched (granted, you need to do this for uranium too but some is naturally in a fissile state). So there's things like breeder reactors that enrich during the cycle but this is challenging and presents other issues such as turning it into weapons manufacturing (increase proliferation concerns). There's a lot of small details that matter a lot. Fwiw, the parent has written a fair amount on this and runs a website with a lot of useful information for anyone curious. You can check their comments too as they usually participate anytime nuclear comes up https://whatisnuclear.com/thorium.html https://whatisnuclear.com/thorium.html

AnthonyMouse 2y ago
Isn't thorium also pretty abundant? Judging by this, the US has around six times as much thorium as uranium: https://en.wikipedia.org/wiki/List_of_countries_by_uranium_reserves https://en.wikipedia.org/wiki/List_of_countries_by_uranium_r... https://en.wikipedia.org/wiki/List_of_countries_by_thorium_resources https://en.wikipedia.org/wiki/List_of_countries_by_thorium_r... I've also never really gotten the proliferation concern. I mean, sure, you don't want to sell a breeder reactor to Iran. But why can't you sell one to PG&E? Are we that concerned that California could get the bomb? Plus, isn't the proliferation thing supposed to be one of the advantages of thorium, since you can't feasibly make a bomb out of the uranium-233 it gets bred into?
- lazide 2y ago
  Yup. The big issue with Thorium is it isn’t fissile at first, and requires an existing nuclear reactor and careful fuel management to actually be usable in a reactor.
- tim333 2y ago
  >A declassified 1966 memo from the US nuclear program stated that uranium-233 has been shown to be highly satisfactory as a weapons material (wikipedia https://en.wikipedia.org/wiki/Uranium-233#Weapon_material https://en.wikipedia.org/wiki/Uranium-233#Weapon_material)
  - AnthonyMouse 2y ago
    From the same article, apparently the infeasiblity is that pure uranium-233 could work, but a normal breeder reactor would also produce a small amount of uranium-232, which is fine for power reactors but not bombs. If you have the resources of the US DoD then you can design a special breeder reactor that uses special thorium, but by that point you could just make one that breeds plutonium out of uranium too.
    - credit_guy 2y ago
      Although in theory a U-233 bomb would work just fine, the fact is that very few U-233 bombs were ever made. I don't think that more than 10, by all the nuclear powers combined. One way or another U-233 is not as good a bomb-making material in practice as it is in theory.
- godelski 2y ago
  > Isn't thorium also pretty abundant? Yes. Even more so! But that doesn't mean it's easy to get. Everything has to be processed at the end of the day. The reason I brought up uranium is that it is easier to fissile. So sure, there's more thorium but it requires more processing. Why use it when we aren't concerned about uranium access? Uranium is already "cheap". (We could get into an analogy with different types of oil if that helps. Like why the US produces so much, exports it, then buys a different type) > I've also never really gotten the proliferation concern. There's two issues here: 1) sure, the US doesn't care if California gets a bomb, but Russia and China sure do. 2) Breeder reactors are reactors that make higher elements. Discussion of thorium are often extremely over simplified. Proliferation always ALWAYS must involve international relationships. When we get into that the logic changes. You need to consider a lot of higher order effects/connections since everything is always being used as leverage for other things. Breeding is also a very complicated topic. Just like enrichment. Look at the Iran deal. They can do enrichment but only do much, right?[0]. Often fine because it's hard to scale and generally noticeable. But the same is true for breeding. Instead of turning one atom into a different isotope (e.g U238 -> U235) you change an atom to a different atom (e.g. Th233 -> Pa233 -> U233). This all happens in the reactor. It's hard to separate but hard to track. You can also keep breeding (fast reactor = more/high energy neutrons), where do you think plutonium comes from? The reason it is better for proliferation concerns is it increases the difficulty. At worst, you need to start earlier. But what I wanted to combat is the misinformation that thorium __can't __ be used for proliferation, making it safe for.., idk, Iran? It's good to add more barriers. I'll also add waste. This is often discussed too. This is again fraught with nuance. We can dramatically reduce waste but we don't. There just isn't much of it and doing more fission is less economical. That is, unless you don't have lots of uranium laying around. That's the case with France, so they "recycle" their waste and in the process this dramatically reduces it. You can fit over 50 years of waste in a Costco and they do. You also can use similar technologies as thorium would need with uranium and still reduce waste. So that points us back to the opening: yes, thorium is abundant, but why go through all that effort when we got plenty of uranium which is cheap and efficient? I recommend poking around AcidBurn's website. He has a lot of good information and I think he's written well in a way that's fairly approachable (it is nuclear, it's by default not approachable and easy to think you understand much more than you do. If you went through a physics degree this is often a confusing class taken at the upper level). [0] When they broke the agreement and made more they suspiciously only made a small amount more which would take a long time to get enough for weapons. But they were also loud. Great strategy because public gets afraid, it's a threat, but they also signal that they're willing you deal but want to renegotiate (only experts would know this though). The interesting part is how their best weapon was our own fear and ignorance.
adrian_b 2y ago
Thorium is more abundant than uranium and as said in the article China already has huge amounts of extracted thorium as a waste product from the extraction of rare-earth metals. Thorium must not be enriched and it cannot be enriched like uranium, because it has only one isotope with a long life, thorium 232, which is the only natural isotope. Natural thorium is not usable as a fission fuel, but it can be transformed into uranium 233, which is a fission fuel, by another nuclear reactor. The extraction of uranium 233 from thorium has nothing to do with uranium isotopic enrichment. It is a process orders of magnitude simpler, because it is just a normal separation of distinct chemical elements. This is actually the reason why thorium reactors have been avoided, because it has been considered that it is too easy to separate the uranium 233 from the fuel, which can be used for making nuclear weapons.
- acidburnNSA 2y ago
  You're right that thorium can't be enriched because there's only one isotope. It needs to be bred to Uranium-233 to work. However, breeding has been more expensive and costly than enrichment, and this is the crux of why thorium use wasn't expanded in the past. To breed thorium to uranium-233, you need a breeder reactor, and you need a chemical separation facility. Together, these are more expensive to build and operate than a centrifuge and simpler non-breeder reactor. In this sense, I disagree that the process is orders of magnitude simpler. I'd argue that it's the opposite! The idea that thorium-derived material can't be easily used to make nuclear explosives is an unfortunately persistent myth. You can easily make very nice weapons material from thorium. As the Livermore weapons designers once said: "If today's weapons were based on U-233, [we] would have no interest in switching to plutonium" [1] [1] https://www.osti.gov/biblio/79078 https://www.osti.gov/biblio/79078
- deleted 2y ago
  [deleted]
- panick21_ 2y ago
  > This is actually the reason why thorium reactors have been avoided, because it has been considered that it is too easy to separate the uranium 233 from the fuel, which can be used for making nuclear weapons. This is absolutely not the reason thorium reactors have been avoided at all. The reality is that uranium enrichment infrastructure existed and fuel isn't a huge part of the cost. Most of the funding happened in the early days and they were of course using uranium, people back then figured that uranium would run out and were interested in breedres. But pretty quickly, uranium was found to be pretty common. Uranium is also just better unless you are doing a thorium thermal breeder. And that design only really works well with a pretty complex reactor setup that most people were simply not interested in.