Natural radioactivity is found everywhere but "radioactive wastes" have higher activity levels than normal.

These wastes include the spoil produced from mines, materials contaminated by the use of radionuclides in medicine, industry and research, contaminated and activated materials from the operation and decommissioning of nuclear power stations and from the production or dismantling of nuclear weapons.

Even though the quantities are rather small, concern is usually focused on the most toxic and longest lived "spent fuel/ high-level waste (SF/HLW)", which is so radioactive over the first few hundred years that the resultant heat production has to be taken into account.

Different types of radioactive waste and their sources in Switzerland

Overview of types of waste: SF - Spent fuel rods from nuclear reactors conditioned for direct disposal. HLW - High-level waste resulting from the reprocessing of spent fuel rods (vitrified waste). TRU or ILW - This waste is classified as intermediate-level (low heat production) but contains significant concentrations of long-lived radionuclides. May include reactor internals and reprocessing waste. L/ILW - Low/intermediate waste - very wide diversity of radioactive materials from the nuclear power industry and users of radionuclides in medicine, industry and research. Conditioned in a solid form (usually cement) for disposal.