Radioactive waste is hazardous waste that contains radioactive material. Radioactive waste is a by-product of processes used in a variety of industries including nuclear medicine, nuclear research, nuclear power, manufacturing, construction, coal and rare-earth mining, and nuclear weapons reprocessing.

Radioactive waste is regulated by government agencies in order to protect human health and the environment. In modern nuclear plants over 96% of spent fuel is recycled back into uranium-based and mixed oxide (MOX) fuel. Radioactivity of the remaining 4% of fission products naturally decreases over time. The material has to be isolated and confined in appropriate disposal facilities for a sufficient period until it no longer poses a threat.

The time radioactive waste must be stored for depends on the type of waste and radioactive isotopes. Current approaches to radioactive waste storage have been segregation and storage for short-lived waste, near-surface disposal for low and some intermediate-level waste, burial in a deep geological repository and transmutation (conversion into a less toxic isotope) for high-level waste.