" The missiles would be packed full of fissionable material, and fission scared her nearly as much as antimatter. It was the dirty, nasty form of nuclear energy. Shut down a fusion reactor, and the only radioactive materials left were those that had been made radioactive by neutron bombardment. Shut down a fission reactor, and you had a deadly, possibly explosive pile of unstable elements with a half-life that meant they would stay hazardous for thousands of years. "

― Christopher Paolini , To Sleep in a Sea of Stars