Plutonium Man sums up the fascination/fear engendered by radioactivity in the 1950s... cast definitely as a villain, he can be played as a tragic victim of circumstance or as a cold vicious seeker of revenge on a society that abandoned him. Read the backstory and decide for yourself which way he will go in your campaign.
Like many supervillians there is little information about what he does when not engaged in super-villainous activities.
Both background and game statistics are presented clearly, and there is a nice - albeit black and white - illustration of Plutonium Man in his costume... although you are left to figure out just why he has the number 94 on his shirt (hint: take a look at the periodic table!). Notes are provided for those who want him at a level other than the PL12 at which he is presented.
There is also a scenario idea using this character, but apart from vague references to a fondness for robbing banks there is no clear indication about his villainous activities let alone why he pursues them. If you want to use him for anything more than a one-shot you may wish to come up with some ideas of your own as to what his overall scheme and rationale may be.