Plot hole: Superman dropping Nuclear Man in the area of a nuclear plant would have made him stronger, since that is giving him a lot of nuclear energy. Instead he is killed.
Athletic JasonSuggested correction: Dropping nuclear man in to a nuclear power plant isn't as silly as it seems, assuming that the nuclear power is far greater than nuclear man he would simply be absorbed by it rather than growing stronger.
That never got shown and the fact that he was able to make a volcano erupt speaks volumes.
Athletic Jason