The licensee or registrant shall ensure that each entrance or access point to a high radiation area has one or more of the following features.
A control device that upon entry into the area causes the level of radiation to be reduced below that level at which an individual might receive a deep dose equivalent of 0.1 rem (1 millisievert) in 1 hour at 30 cm from the source of radiation from any surface that the radiation penetrates;
A control device that energizes a conspicuous visible or audible signal so that the individual entering the high radiation area and the supervisor of the activity are made aware of the entry; or
Entryways that are locked except during periods when access to the areas is required with positive control over each individual entry.