(1)   Spent nuclear fuel is used fuel from nuclear power plants.

(2)   Uranium milling residues, known, as mill tailings are the rock and soil that remains after uranium is removed from mined ore.

(3)   Radioactive waste that contains more than a specified concentration of elements heavier than uranium (transuranics).

All other radioactive waste is low-level radioactive waste.

The Code of Federal Regulations, Title 10, Part 61 defines three classes of commercial low-level radioactive waste, they are Class A, Class B, and Class C.  Limits on concentrations of specific radioactive materials allowed in each class can be found in 10 CFR 61.55.  Class A waste contains the lowest concentration of radioactive materials, Class B is next and Class C would have the highest.  The limits on concentrations are based on the half-life of the material. These wastes are buried in a low level radioactive waste burial site.  Some examples of LLRW are contaminated lab equipment, small tools, plumbing and ventilation fixtures, personal protective wear, paper and plastic (DAW), fluids, filters from sampling devices, and animal carcasses.

Radioactive waste not meeting the criteria for these classes is called Greater than Class C and is the responsibility of the federal government; it is stored in a geologic repository. Visit the Yucca mountain web page to learn more and get an update on the status.