Thanks. Very interesting article.
Someone more knowledgeable than I can perhaps tell us what level of enrichment is necessary to make a Hiroshima "Little Boy" type bomb function.
The linked article suggests that Uranium is naturally about 1% U-235 and that enrichment to 3% yields reactor grade fuel. The article suggests that the amount of fuel in "Little Boy" may still be classified. I can believe that. One of the uncertainties is the value of critical mass. Since Little Boy seems to have been the combining of two masses, each must have been less than critical mass and the sum was more than critical mass.
Can someone tell me, is the critical mass of some level of enriched uranium a known quantity or are such values all classified?
Also, the article discusses the fact that crushing a small sphere of polonium/beryllium releases a spray of neutrons. Can someone explain that effect to me.
