In 1939-1940, what does Robert Oppenheimer do that makes Robert Oppenheimer a true genius in the eyes of the author?

At the conference, Bohr and Fermi present papers on the how a neutron can split uranium. At this time, this is all theory in the minds of the nuclear scientists. Oppenheimer reads the materials and decides that fission is real. His true genius is seen by his taking this information and drawing a crude plan for an atomic bomb.