What is a lost source in radiation safety?

A lost source refers specifically to a radioactive source that cannot be located or retrieved. This situation poses significant safety concerns within radiation safety protocols because a lost source can potentially expose individuals to harmful radiation or lead to contamination of the environment if it is not adequately contained or identified. Proper management and accounting for radioactive materials are crucial to minimize risks associated with lost sources.

In contrast, the other options describe scenarios that do not fit the definition of a lost source. A damaged source may still be located but poses risks due to its condition. A source that has been properly disposed of no longer presents a hazard in terms of being a lost source, as it is accounted for in waste management systems. Similarly, a source that has been rendered inactive does not pose the same risks as a lost source, as it is no longer capable of emitting radiation. Thus, the correct choice highlights the critical issue of accountability and safety in radiation management.