Nuclear Weapons The nuclear age opened with the development of the atomic bomb during World War II. Many people believed that weapons capable of mass destruction would make war unthinkable in the future. They hoped that the world would learn to live in peace. But a race to develop ever more powerful weapons soon began. Nuclear weapons are weapons of mass destruction powered by atomic processes. Using nuclear fission or fusion, they produce huge explosions and hazardous radioactive by products. Most are meant to be delivered by artillery,plane, ship, or ballistic missile, but some have been min