average age of the world's nuke plants is 25 years percent aging nuclear reactors worldwide average age of the world's nuke plants is 25 years percent percent average age of the world's nuke plants is 25 years average age of the world's nuke plants is 25 years percent aging nuclear reactors worldwide aging nuclear reactors worldwide percent aging nuclear reactors worldwide average age of the world's nuke plants is 25 years average age of the world's nuke plants is 25 years