No Nuclear Weapon

Timeline
1921: Eintein die in a confuse episode in USA, in her first visit to that country

1933: Leo Szilárd fled to London to escape Nazi persecution, where he read an article written by Ernest Rutherford in The Times which rejected the possibility of using atomic energy for practical purposes.

1946: The US Air Force is still booming Japan, but the Emperor of Japan, Hiroito not surrender