10 CFR §835.501

1. (a)Personnel entry control shall be maintained for each radiological area.
2. (b)The degree of control shall be commensurate with existing and potential radiological hazards within the area.
3. (c)One or more of the following methods shall be used to ensure control:
   1. (1)Signs and barricades;
   2. (2)Control devices on entrances;
   3. (3)Conspicuous visual and/or audible alarms;
   4. (4)Locked entrance ways; or
   5. (5)Administrative controls.
4. (d)Written authorizations shall be required to control entry into and perform work within radiological areas. These authorizations shall specify radiation protection measures commensurate with the existing and potential hazards.
5. (e)No control(s) shall be installed at any radiological area exit that would prevent rapid evacuation of personnel under emergency conditions.