Originally Posted by deersmeller
How close? I do not know either.

I suppose that it was fairly accurately assessed after the war.


The post WW2 Strategic Assessments described both Germany and Japan's nuclear efforts. They did refine uranium and had working reactors, but were never able to sustain criticality of the fuel, even experimentally. These reactors were very small, not at all like the large Y-12 and K-25 reactors at Oak Ridge TN. These plants were very large and produced enough fissile material for about 6 weapons.