To what level should the activity of surfaces be reduced when decontaminating areas where radioactive materials were handled?

When decontaminating areas where radioactive materials were handled, the activity of surfaces should ideally be reduced to at or near background levels. This standard is crucial because it ensures that any residual radioactivity does not pose an undue risk to health and safety for personnel working in or around these areas or for the public.

Background levels refer to the natural radiation present in the environment, which includes cosmic rays and terrestrial sources. By bringing the levels back to these rates, facilities can confirm that they are not introducing excessive radiation into the environment, thereby maintaining safety protocols.

Reducing radioactive contamination to at or near background levels allows for safe use of the space and aligns with regulatory guidelines for radiation protection, ensuring the well-being of staff and the public. It also serves as a practical measure since achieving a zero level is often impossible due to the persistent nature of some radioactive materials, and maintaining the activity at two times the background level still poses health risks. Therefore, the goal is to ensure that any residual contamination remains at a safe threshold reflective of natural environmental levels.