Radioactive waste represents only a small portion of the waste produced by human activities. However, because it contains radionuclides, some of which may remain hazardous for long periods of time, it must be carefully managed to protect people and the environment. Close attention is therefore paid to the treatment, conditioning, storage and eventual disposal of radioactive waste.

Radioactive waste can be classified according to its activity, the types and half-lives of the radionuclides it contains, and its physical form as solid, liquid or gaseous waste. Different types of waste require different methods of handling, treatment, conditioning and storage, as well as different disposal solutions. Disposal facilities are designed to contain and isolate radioactive material from people and the environment for as long as necessary. Long-lived and high-level radioactive waste, including spent nuclear fuel if declared as waste, may require disposal in deep geological repositories hundreds of metres underground, where engineered and natural barriers provide isolation over periods of hundreds of thousands of years or longer.