Nuclear energy is generated by initiating a process called nuclear fission (the splitting of atoms). Very large atoms like Uranium are unstable and release a lot of energy when split apart. They also release neutrons which will then fly around and split up other uranium atoms, releasing more energy and more neutrons and the cycle continues. This chain reaction generates A LOT of energy. The energy is then used to heat up water into steam. The steam flows through pipes and into a turbine, spinning the turbine around (just like wind does to a wind mill). As the turbine spins around it powers a generator to create electricity, which can then be harnessed and distributed.