4 ms·

I’m surprised at the amount of Uranium the US needed (for just the Manhattan project?) the US secured 1,200 tonnes of Congolese uranium, which was stockpiled o

by runeb 6y ago

I’m surprised at the amount of Uranium the US needed (for just the Manhattan project?) the US secured 1,200 tonnes of Congolese uranium, which was stockpiled on Staten Island, US, and an additional 3,000 tonnes that was stored above ground at the mine in Shinkolobwe. But it was not enough. US Army engineers were dispatched to drain the mine, which had fallen into disuse, and bring it back into production. Under Belgian rule, Congolese workers toiled day and night in the open pit, sending hundreds of tonnes of uranium ore to the US every month.

_n_b_ 6y ago
Natural uranium is 0.7% U-235, and enrichments of 80%+ are needed for U-based weapons (like Little Boy). The enrichment process used during the Manhattan project (electromagnetic and then gaseous) not perfectly efficient, and there are losses during conversion, but assuming 100% efficiency that means just Little Boy required 8 tons of raw U. If you add up all the work going on, all the experiments, all the piles (reactors) off consuming uranium, this figure doesn’t seem too surprising to me.
- bbarnett 6y ago
  From the article: Mines in the US and Canada were considered a “good” prospect if they could yield ore with 0.03% uranium. At Shinkolobwe, ores typically yielded 65% uranium. The waste pile of rock deemed too poor quality to bother processing, known as tailings, contained 20% uranium.
  - ivann 6y ago
    Those are the yields of uranium in the ore. The 80%+ needed is the quantity of the Uranium-235 isotope.
  - sandworm101 6y ago
    If it were 65% uranium, the mine itself would be a massive nuclear reactor. (A situation that did happen elsewhere in prehistory.) It would heat up and into a red-hot cauldron. 65% is the richness of the ore not the percentage of uranium in the rock overall.
    - timothevs 6y ago
      Quite interesting, do you have an article, or a paper about the prehistoric episode you mentioned? I’m genuinely curious.
      - intotheabyss 6y ago
        The only naturally occurring nuclear fission reactor was found to be in Oklo, Gabon in Central Africa and was thought to be active about 1.5 billion years ago. https://en.wikipedia.org/wiki/Natural_nuclear_fission_reactor https://en.wikipedia.org/wiki/Natural_nuclear_fission_reacto...
      - kenned3 6y ago
        This provides much better coverage: https://blogs.scientificamerican.com/guest-blog/natures-nuclear-reactors-the-2-billion-year-old-natural-fission-reactors-in-gabon-western-africa/ https://blogs.scientificamerican.com/guest-blog/natures-nucl...
    - kenned3 6y ago
      This is NOT the case, even if the mine was 100% Uranium this would not happen, at least not today. As someone else pointed out, the world did have a natural reactor, Oklo, Gabon 1.5 billion years ago. When Uranium is refined, they are enriching the U235 vs U238. The ratio is too low today to sustain any natural reactors, but 1.5 billion years ago this wasnt the case.
      - sandworm101 6y ago
        Not the case on day-1, but an open pit of 65% uranium isn't a typical lab experiment. Add some rain, some evaporation, some oxygen, countless other micro effects, and after a while you will get localized concentrations of U235. Then things start to get interesting as the fertile U238 is changed into other things. I'm not saying that that actually happened, just that a hypothetical multi-kiloton pile of 65% natural uranium isn't a neutral pile of sand.
        6y ago
martincmartin 6y ago
They also wanted to keep it from the Germans. Before war, much of the foundations of atomic physics were developed by people in the Axis countries. It was plausible that Germany had a nuclear program as big as the American one. Denying them fuel was important. See the sabotage of Norwegian heavy water: https://en.wikipedia.org/wiki/Norwegian_heavy_water_sabotage https://en.wikipedia.org/wiki/Norwegian_heavy_water_sabotage
- ben7799 6y ago
  "The Winter Fortress" is a fantastic book about the Norwegian sabotage of the heavy water plant... really highly recommended.
- sandworm101 6y ago
  >> It was plausible that Germany had a nuclear program as big as the American one. Plausible only for those without knowledge of the extent of the US program. Even among those involved, few had perspective on exactly how much of the US economy was being funnelled into the nuclear program. The Manhattan Project famously at some points used roughly 10% of the electricity available in the united states, a country with an infrastructure relatively untouched by war. There is absolutely no way that WWII Germany could have sustained anything close to a similar effort. They had to brains to understand the physics, but not the raw industrial power necessary to turn that into a practical weapon.
  - cryptonector 6y ago
    The Manhattan project studied four different Uranium enrichment solutions (none of being centrifuges'; ultimately settled on diffusion) and pursued two completely different bomb designs. The uranium bomb required a high degree of enrichment, while the plutonium bomb required a reactor. I don't have the figures, but I imagine a great deal of the electric power consumed by the Manhattan project was for making heavy water and enriching uranium. The Japanese had two different atomic bomb projects, as usual, one for the navy and one for the army. As I understand it, one of the (the navy's) got pretty close. But details of the Japanese effort are hard to find. A much more focused project that consumed a smaller portion of Europe's industrial capacity was somewhat plausible, at least up until the scuttling of Norway's heavy water. A serious German bomb effort could have done the minimum uranium enrichment (using centrifuges, perhaps) needed to breed plutonium in a reactor, and then yielded plutonium bombs, at much lower cost than the Manhattan project. Necessity being the mother of invention, and with all the energetic and industrial constraints they had it's not too farfetched to suppose they would have landed an idea like that. Still, once they lost access to Norway's heavy water, it would have cost them a great deal of electric power to make more, so there's that.
NicoJuicy 6y ago
This was something i read recently in the history of Belgium. Since the World War II, Belgian shared their Uranium supply with the US and the UK ( https://en.wikipedia.org/wiki/Belgian_Congo_in_World_War_II#Uranium https://en.wikipedia.org/wiki/Belgian_Congo_in_World_War_II#... ), done as part of repayment for allied support in the war. So this little country was actually the main / sole supplier through Congo for the atom bomb / nuclear energy in the US. Congo gained independence in 1960.

by runeb 6y ago

_n_b_ 6y ago

Natural uranium is 0.7% U-235, and enrichments of 80%+ are needed for U-based weapons (like Little Boy). The enrichment process used during the Manhattan project (electromagnetic and then gaseous) not perfectly efficient, and there are losses during conversion, but assuming 100% efficiency that means just Little Boy required 8 tons of raw U. If you add up all the work going on, all the experiments, all the piles (reactors) off consuming uranium, this figure doesn’t seem too surprising to me.

bbarnett 6y ago
From the article: Mines in the US and Canada were considered a “good” prospect if they could yield ore with 0.03% uranium. At Shinkolobwe, ores typically yielded 65% uranium. The waste pile of rock deemed too poor quality to bother processing, known as tailings, contained 20% uranium.
- ivann 6y ago
  Those are the yields of uranium in the ore. The 80%+ needed is the quantity of the Uranium-235 isotope.
- sandworm101 6y ago
  If it were 65% uranium, the mine itself would be a massive nuclear reactor. (A situation that did happen elsewhere in prehistory.) It would heat up and into a red-hot cauldron. 65% is the richness of the ore not the percentage of uranium in the rock overall.
  - timothevs 6y ago
    Quite interesting, do you have an article, or a paper about the prehistoric episode you mentioned? I’m genuinely curious.
    - intotheabyss 6y ago
      The only naturally occurring nuclear fission reactor was found to be in Oklo, Gabon in Central Africa and was thought to be active about 1.5 billion years ago. https://en.wikipedia.org/wiki/Natural_nuclear_fission_reactor https://en.wikipedia.org/wiki/Natural_nuclear_fission_reacto...
    - kenned3 6y ago
      This provides much better coverage: https://blogs.scientificamerican.com/guest-blog/natures-nuclear-reactors-the-2-billion-year-old-natural-fission-reactors-in-gabon-western-africa/ https://blogs.scientificamerican.com/guest-blog/natures-nucl...
  - kenned3 6y ago
    This is NOT the case, even if the mine was 100% Uranium this would not happen, at least not today. As someone else pointed out, the world did have a natural reactor, Oklo, Gabon 1.5 billion years ago. When Uranium is refined, they are enriching the U235 vs U238. The ratio is too low today to sustain any natural reactors, but 1.5 billion years ago this wasnt the case.
    - sandworm101 6y ago
      Not the case on day-1, but an open pit of 65% uranium isn't a typical lab experiment. Add some rain, some evaporation, some oxygen, countless other micro effects, and after a while you will get localized concentrations of U235. Then things start to get interesting as the fertile U238 is changed into other things. I'm not saying that that actually happened, just that a hypothetical multi-kiloton pile of 65% natural uranium isn't a neutral pile of sand.
      - 6y ago

martincmartin 6y ago

They also wanted to keep it from the Germans. Before war, much of the foundations of atomic physics were developed by people in the Axis countries. It was plausible that Germany had a nuclear program as big as the American one. Denying them fuel was important. See the sabotage of Norwegian heavy water: https://en.wikipedia.org/wiki/Norwegian_heavy_water_sabotage https://en.wikipedia.org/wiki/Norwegian_heavy_water_sabotage

ben7799 6y ago
"The Winter Fortress" is a fantastic book about the Norwegian sabotage of the heavy water plant... really highly recommended.
sandworm101 6y ago
>> It was plausible that Germany had a nuclear program as big as the American one. Plausible only for those without knowledge of the extent of the US program. Even among those involved, few had perspective on exactly how much of the US economy was being funnelled into the nuclear program. The Manhattan Project famously at some points used roughly 10% of the electricity available in the united states, a country with an infrastructure relatively untouched by war. There is absolutely no way that WWII Germany could have sustained anything close to a similar effort. They had to brains to understand the physics, but not the raw industrial power necessary to turn that into a practical weapon.
- cryptonector 6y ago
  The Manhattan project studied four different Uranium enrichment solutions (none of being centrifuges'; ultimately settled on diffusion) and pursued two completely different bomb designs. The uranium bomb required a high degree of enrichment, while the plutonium bomb required a reactor. I don't have the figures, but I imagine a great deal of the electric power consumed by the Manhattan project was for making heavy water and enriching uranium. The Japanese had two different atomic bomb projects, as usual, one for the navy and one for the army. As I understand it, one of the (the navy's) got pretty close. But details of the Japanese effort are hard to find. A much more focused project that consumed a smaller portion of Europe's industrial capacity was somewhat plausible, at least up until the scuttling of Norway's heavy water. A serious German bomb effort could have done the minimum uranium enrichment (using centrifuges, perhaps) needed to breed plutonium in a reactor, and then yielded plutonium bombs, at much lower cost than the Manhattan project. Necessity being the mother of invention, and with all the energetic and industrial constraints they had it's not too farfetched to suppose they would have landed an idea like that. Still, once they lost access to Norway's heavy water, it would have cost them a great deal of electric power to make more, so there's that.

NicoJuicy 6y ago

This was something i read recently in the history of Belgium. Since the World War II, Belgian shared their Uranium supply with the US and the UK ( https://en.wikipedia.org/wiki/Belgian_Congo_in_World_War_II#Uranium https://en.wikipedia.org/wiki/Belgian_Congo_in_World_War_II#... ), done as part of repayment for allied support in the war. So this little country was actually the main / sole supplier through Congo for the atom bomb / nuclear energy in the US. Congo gained independence in 1960.