Uranium cubes reveal why the German nuclear project failed

(arstechnica.com)

47 points | by rbanffy 2 days ago

4 comments

  • leonidasrup 1 hour ago
    Boron contamination of graphite also slowed the Manhattan Project:

    " Fermi writes that "The results of this experiment was [sic] somewhat discouraging" presumably because of the absorption of neutrons by some unknown impurity. So, in December 1940 Fermi and Szilard met with Herbert G. MacPherson and V. C. Hamister at National Carbon to discuss the possible existence of impurities in graphite. During this conversation it became clear that minute quantities of boron impurities were the source of the problem. "

    https://en.wikipedia.org/wiki/Nuclear_graphite

    • schiffern 34 minutes ago
      Sounds like a good time travel story: the mission is to go back in time and plant a single uranium cube, to be found ~80 years hence, to convince people that the German bomb project was doomed so that– ahh, but let's not spoil it! :)
      • TomJansen 9 minutes ago
        So that WW2 had to go on for an extra 2/3 years?
  • thisisauserid 2 days ago
    This is central to the plot of D: Heavy Water, Neal Stephenson's second installment of the Bomb Light Trilogy.
    • the__alchemist 52 minutes ago
      Holy shit this is out? I went to the book tour for Polostan. Ordered; ty!
  • AndrewKemendo 1 hour ago
    Awesome article and interesting to see Heisenberg get it wrong. It really was a perfect situation for the US because we could get all the radioactive material with little issue.

    A clean reminder that logistics is everything.

    Also cool that the author is married to Sean Carroll.

  • mmooss 1 hour ago
    Relatively recently, recordings were released of conversations between captured Nazi scientists held at a house in the UK (I think I saw it on HN). They were housed together and the house was bugged purposely to capture casual conversation for intelligence purposes.

    IIRC one conclusion they/some of the scientists drew was that the culture of the Nazi regime - the paranoia, fear, and violence - made a project on that scale impossible. Enough talented, high-ego people could not work together on project that large and demanding.

    Also, IIRC, when the Hiroshima bomb was announced, many couldn't believe it. They had been working on a power generation reactor as a first step - though I'm not sure the OP fits that story?

    Also, maybe Heisenberg didn't want to succeed? Has that ever been resolved to some degree?

    • ZnerflBerp 23 minutes ago
      The sheer economic costs of the manhattan project were prohibitive to a nation like Germany, even if they'd managed to build a functional project team.

      (how many nations had 14,700 tons of silver lying around)

      • throwaway81523 4 minutes ago
        The silver bus bars in the magnetic separators were kind of a stunt, if that's what you're thinking of.
    • jcranmer 9 minutes ago
      > Also, maybe Heisenberg didn't want to succeed? Has that ever been resolved to some degree?

      From the Farm Hall transcripts, it seems that Heisenberg was "happy" to have been working on a reactor and not a bomb, but from context, this seems less like an objection to the principle of working on a weapon and more like gratitude that the Allies couldn't hang him for working on an atomic bomb. Recall that the conversations took place after Germany had been utterly defeated and the scientists were prisoners at the mercy of the British--prisoners in a gilded cage, but prisoners nonetheless.

    • kragen 23 minutes ago
      > one conclusion they/some of the scientists drew was that the culture of the Nazi regime - the paranoia, fear, and violence - made a project on that scale impossible

      This makes me think about the pervasive classification and paranoia in the "defense" contractors supporting the US Department of "Defense". Any information that's classified, even at the lowest "confidential" level, is only provided on a "need-to-know" basis. And unclassified projects are sort of looked down on, so there's a perverse incentive to classify more than necessary. This "secretive, isolationist approach" seems like it probably prevents a lot of groups from "sharing information or resources", in the article's words (though it concludes that wasn't the biggest problem facing the German effort).

      When sharing classified information that someone might not need to know might be a crime, and might get your clearance pulled even if it's not, the incentives run strongly counter to sharing information. Consequently, I confidently claim that there are very, very few people in a position to serendipitously make significant discoveries that involve combining two or three different classified facts.

      (I don't actually know this, because I don't know any classified facts.)

      Maybe this is part of the sclerosis that causes the US defense-industrial complex to "basically produce useless junk", in the words of Les Earnest (https://www.youtube.com/watch?v=Ych6pvLMKCU), and which prompts Sergey Tovkach to say, "There isn’t a single Western drone that’s proven itself effective in this conflict." (https://www.youtube.com/watch?v=RmfNUM2CbbM). Maybe that's why Russian propaganda in 02024 reported that Ukraine had to withdraw the USA-made M1A1 tanks far from the front (https://www.youtube.com/watch?v=aCIN-t3VxJ0).