Waste in general is considered to be material that has no further use. Every human activity results in the generation of waste, whether it comes from private homes, office blocks, factories, power plants or mining sites. Household waste is typically disposed of at municipal refuse dumps, but other forms of waste such as chemical and radioactive waste need to be disposed of in specially prepared disposal systems, called repositories.
Radioactive waste is different from other types of waste in that it contains radioactivity above certain concentrations. This waste needs to be disposed of in a special manner that isolates it from humans and the environment for as long as necessary. Radioactive waste in contrast to chemical waste, for instance, loses its radioactivity over time and therefore becomes less harmful. Chemical waste on the other hand stays toxic forever.

Radioactive waste results from various processes involving research and development activities, radioisotope applications in industry and hospitals, nuclear energy production and mining and minerals processing.

Radioisotope applications using sealed radioactive sources result in the production of limited quantities of operational waste and in the discharge of spent sources. Nuclear power plants such as Koeberg produce spent nuclear fuel, low and intermediate level waste. Spent nuclear fuel is not necessarily a waste, as it can be reprocessed in order to extract useful materials from it for re-use. The mining and minerals processing industry typically produces large quantities of very low level waste as well as concentrated amounts of naturally occurring radioactive waste.

Radioactive waste consists of materials with radioactive properties that vary significantly depending on the kind of material and concentration involved. The waste can occur in the form of large quantities of waste containing low concentrations of radioactive materials (soil, sludge, etc.), drummed operational waste containing contaminated items (protective clothing, rags, etc.), solidified operational waste containing spent resins and other radioactive components, and spent nuclear fuel assemblies containing high concentrations of radioactive (fissile) components.

Radioactive waste is usually a by-product of nuclear power generation and other applications of nuclear fission or nuclear technology, such as research and medicine.- (Source: Wikipedia)