Radioactive waste is a type of hazardous waste that contains radioactive material. Radioactive waste is a result of many activities, including nuclear medicine, nuclear research, nuclear power generation, rare-earth mining, and nuclear weapons reprocessing. The storage and disposal of radioactive waste is regulated by government agencies in order to protect human health and the environment.
It is broadly classified into low-level waste (LLW), such as paper, rags, tools, clothing, which contain small amounts of mostly short-lived radioactivity, intermediate-level waste (ILW), which contains higher amounts of radioactivity and requires some shielding, and high-level waste (HLW), which is highly radioactive and hot due to decay heat, so requires cooling and shielding.
In nuclear reprocessing plants about 96% of spent nuclear fuel is recycled back into uranium-based and mixed-oxide (MOX) fuels. The residual 4% is fission products which are highly radioactive High-Level Waste. This radioactivity naturally decreases over time, so the material is stored 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. Short-term approaches to radioactive waste storage have been segregation and storage on the surface or near-surface. Burial in a deep geological repository is a favored solution for long-term storage of high-level waste, while re-use and transmutation are favored solutions for reducing the HLW inventory.
A summary of the amounts of radioactive waste and management approaches for most developed countries are presented and reviewed periodically as part of the International Atomic Energy Agency (IAEA)'s Joint Convention on the Safety of Spent Fuel Management and on the Safety of Radioactive Waste Management.