As large sources of uranium have been found in Canada the uranium mines in the southwest have been abandon. The estimated costs of waste containment from those mines is near 10 billion dollars. Its not like it will decompose in 10 years it takes 250,000 years. This country has only been around 223 years. 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 are left over are also very radioactive. This 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. The economic fallout from this nuclear waste in America alone has been estimated at upwards of 31 billion dollars per year.