In nuclear power plants, a process called fission generates nuclear waste.
Fission occurs when uranium atoms are split into smaller atoms.
A tremendous amount of energy is released, and this energy is used to generate electricity. However, many of the smaller atoms left over are also very radioactive. This all happens in large metal rods called fuel rods. About once every 18 months, the fuel rods have to be removed, but the rods still contain radioactive atoms. A spent fuel rod is nuclear waste.