After the final closure of a nuclear facility, it must be decommissioned. Radioactive components and materials such as the reactor and associated piping must be removed. Used nuclear fuel is placed in dry storage until final disposal.
Radioactive material that has been accumulated inside or on the surface of various equipment (pipes, heat exchangers, building material, …) needs to be removed, controlled, conditioned and prepared for final disposal.
Radioactive waste is defined as radioactive material which cannot be economically recycled and which has to be disposed in a safe way.
In consideration of the limited space of final storage areas, it is most important to differentiate radioactive waste from reusable materials and conventional waste.
The gamma activity is measured with special scanner systems while the determination of pure alpha- and beta emitters has to be performed destructively.
The list of long-lived pure alpha and beta emitting radionuclides (e.g. actinides, Sr-90, Tc-99, Ni-59/63,…) is important and conventional methods are often tedious and include the use of hazardous reagents.