Character Analysis
When you think of Kallner, think of the atomic bomb. See, Kallner isn't a scientist—he's a military man. (Well, he might be a scientist also, but we don't see that side of him.) But he's in charge of this big scientific research project to develop the Hyperatomic Drive. When we first meet him, Kallner is wearing a uniform (Little Lost Robot.20), which reminds us that he is a military man in charge of the scientific Hyper Base.
And that's why you should think of the atomic bomb and the Manhattan Project. The Manhattan Project was the secret military program to develop the atomic bombs that were used in 1945 on Hiroshima and Nagasaki. (The program wasn't so secret after that.) Now, even though the Manhattan Project was a scientific research program, the guy in charge of it all was Brigadier-General Leslie Groves, a military man.
So, when Asimov was writing this story in 1947, it's definitely possible that he was thinking about the Manhattan Project; and that when he was writing about Major-General Kallner, he was thinking about Brigadier-General Groves.