Nuclear energy comes from mass-to-energy conversions that occur in the splitting of atoms larger than Iron or joining atoms smaller than Iron. The small amount of mass that is lost in either of these events follows. In the 1930s and ’40s, humans discovered this energy and recognized its potential as a weapon. Technology developed in the Manhattan Project successfully used this energy in a chain reaction to create nuclear bombs. Soon after World War II ended, the newfound energy source found a home in the propulsion of the nuclear navy, providing submarines with engines that could run for over a year without refueling. This technology was quickly transferred to the public sector, where commercial power plants were developed and deployed.