&gt; Previously in the article they mentioned that this 10kg of Uranium believed to be for sale on the black market is a fifth of what you would need for a Hiroshima-type weapon but it&#x27;s just about enough for a well designed implosion nuke.<p>With 60kg of HEU I could build Little Boy by myself in my garage with parts I can get at Home Depot and Cabela&#x27;s.<p>With 10kg of HEU I could build Fat Man with a breeder reactor, a couple hundred thousand in precision machine tools, several tens of thousands in specialty electronics, and a small team of specialists.<p>Both are <i>possible</i>, but one is far more feasible to do than the other for a terrorist group.  That said, 10kg in a Little Boy type device would still cause a pretty big boom.  The damage from the radiological hysteria that would follow its use would be far greater than the explosive damage, though.