incadink

I think there is something you are missing regarding yield calculations. The amount of fissile material used in an atom bomb is not the same as the critical mass of the element. The Hiroshima bomb was a gun-type weapon. It traded off effiency for simplicity and reliability. The bottom line is not all the U-235 was converted to energy. A good estimate is about 40% of the fissile material. That has to be factored into your equations.