Transmutation involves converting radionuclides into other nuclides by irradiation. It is initiated by bombarding the material to be transformed with neutrons or protons, which triggers various nuclear physical processes and results in new atomic nuclei.
Transmutation is repeatedly advocated as a means of transforming long-lived radionuclides into shorter-lived nuclides. This is theoretically possible, but cannot be implemented in practice using current technology. The processes involved are presently the subject of extensive research, with the aim of being able to transform long-lived radioactive wastes into shorter-lived wastes in the future. Even if transmutation technology becomes practicable, geological repositories will still be required for the resulting shorter-lived wastes and for low- and intermediate-level waste that is not suitable for transmutation.