I was making a rhetorical point, but it works if you switch out 'theoretically' with 'actually', and 'two weeks before' with 'while the first nuclear reactor was supercritical in Chicago'.
I'm pretty certain that the practicality of a nuclear chain reaction wasn't widely accepted in December of 1942, even though fission was first demonstrated by Meitner and Hahn three years before.
I'm pretty certain that the practicality of a nuclear chain reaction wasn't widely accepted in December of 1942, even though fission was first demonstrated by Meitner and Hahn three years before.