A tale of lost WW2 uranium cubes shows why Germany’s nuclear program failed

When University of Maryland physicist Timothy Koeth received a mysterious heavy metal cube from a friend as a birthday gift several years ago, he instantly recognized it as one of the uranium cubes used by German scientists during World War II in their unsuccessful attempt to build a working nuclear reactor. As Heisenberg himself reported, the German scientists’ final experiment failed because the amount of uranium in the cubes was insufficient to trigger a sustained nuclear reaction. During their quest, Koeth and Hiebert uncovered a box of declassified documents about German uranium in the National Archives and discovered there were about 400 other uranium cubes from a separate reactor experiment by the Gottow group.

Source: arstechnica.com