The procedure of closing down a chemical process or nuclear facility to a point that permits the release of the property for demolition and site clearance. In nuclear power and reprocessing plants, decommissioning begins by closing down the facility, followed by reducing residual radioactivity to a low level. In nuclear power plants, the process begins with the removal of the nuclear fuel, coolant, and radioactive process waste. The three recognized stages of decommissioning involve safe enclosure, partial removal with safe enclosure, and the complete removal of materials.