Uggh. Not another article on this crap.
They're never very clear that the author is only claiming a "dirty bomb" test, which is just slapping some radioactive stuff around a regular high explosive. Not a very effective weapon, and it is to a true nuclear bomb what a BB Gun is to an M-16.
A crude nuclear device, meaning, when they tested it, the bomd replied the chief researcher was a pooftah, questioned his legitimate heritage, and things of that sort (only, in gutteral German).
Didn't think of a dirty bomb. Rhodes mentioned that and stated that both sides considered using synthetic radioisotopes but both concluded that the concept was not practical.
Equally unknown by most of the world is that the "fixin's "for a dirty bomb were shipped to Japan in a submarine. Japan had chosen San Francisco as the target, and it was only the decision by the U-boat captain to deliver the radioactive material to the US east coast, instead, that prevented the first use of a "dirty" bomb ever.
I saw a documentary on the History Channel that said the same thing - the Nazis had built a dirty bomb. But there was no indication it had been tested. From this write up it sounds pretty iffy, all based on some circumstantial evidence.