High-level waste (HLW) is the material that remains following the
reprocessing of spent nuclear fuel and irradiated targets from reactors.
The HLW is highly radioactive and generates heat on its own. Some of
its elements will remain radioactive for thousands of years. Because of
this, HLW must be managed very carefully and all handling must be
performed from behind heavy protective shielding.
Low-level waste (LLW) is any radioactive waste that is not HLW, spent
nuclear fuel, TRU waste, or uranium mill tailings. The LLW is typically
contaminated with small amounts of radioactivity dispensed in large
amounts of material. The LLW is generated in every process involving
radioactive materials in the DOE including decontamination and
Mixed waste (MW) is waste that contains both radioactive and
hazardous wastes. Any of the types of radioactive waste described can
be a mixed waste if it contains any hazardous wastes. In fact, all of
DOE's HLW is mixed waste because of the chemicals used to reprocess
the fuel that resulted in the generation of the material or because it is
suspected to contain hazardous materials.
Transuranic (TRU) waste refers to waste materials containing elements
with atomic numbers greater than 92. These elements are generally
alpha-emitting radionuclides that decay slowly. The TRU waste contains
a concentration of these elements greater than 100 nCi/g. The TRU
waste is not as intensely radioactive as HLW. The TRU waste also
decays slowly, requiring long-term isolation.
Sanitary waste is waste that is neither hazardous nor radioactive.
Because of its quantity, concentration, and physical, chemical, or
infectious characteristics, hazardous waste may cause or significantly
contribute to an increase in mortality, or an increase in serious
irreversible or incapacitating reversible illness; it may pose a potential
hazard to human health or the environment when improperly treated,
stored, transported, disposed of, or otherwise managed.