What if radiation worked like in comic books? You can gain super-powers proportionate in strength to your distance from the reactor core when it melted down.
I’m sure governments would quickly start irradiating their top soldiers (which might not be a …great idea?), but what about the enemy? Blow up a soviet nuclear reactor and everyone not killed in the explosion will suddenly develop super-powers.
Mostly those new supers will be a mess for the Soviet government to clean up (which is why the US blew up the reactor in the first place), but what about the people who are mad their homes and normal lives were obliterated? I imagine they’d want to…avenge that destruction?