Yeah I did not take the theme literally but there are parallels
I wanted to avoid the obvious choice and go for something different but hear me out. There's the "death" of the run where the reaction dies out and you have the "opportunity" to upgrade and try again. The atoms "die" when they get hit by a neutron but they get to further the chain reaction. Then there's the death of the save file when you reach the end with the opportunity to get a faster end time. Then there's the historical death of the scientists working on the demon core for the opportunity to advance nuclear physics. So while you aren't literally dying until you reach the end the theme is throughout the game.
