Removal of regulatory control from material whose activity concentration is below set clearance levels, for example around 0.1 Bq per gram for cobalt-60 and caesium-137 in international guidance. Cleared material can be recycled, reused or sent to ordinary landfill. Demonstrating clearance requires careful measurement and documentation, and it is central to decommissioning, where most of the plant's mass is metal and concrete that can be cleared.
Scaffold poles passed clearance on the bulk monitor, they can go back to the contractor yard.
Also heard as
- free release
- unconditional release
Related terms
Radwaste
Radioactive waste produced by nuclear facilities, and the plant department that processes and ships it.
Becquerel
The SI unit of radioactivity, equal to one atomic decay per second.
Smear
A wipe of a surface with filter paper, counted to measure how much removable contamination is present.
Decontamination
Removal of radioactive contamination from people, tools, surfaces or systems to reduce dose and spread.