(1) The mechanism that moves the sources of a panoramic or beam-type irradiator must require a key to actuate. Actuation of the mechanism must cause an audible signal to indicate that the sources are leaving the shielded position. Only one key may be in use at any time, and only operators or facility management may possess it. The key must be attached to a portable radiation survey meter by a chain or cable. The lock for source control must be designed so that the key may not be removed if the sources are in an unshielded position. The door to the radiation room must require the same key.

(2) The console of a panoramic or beam-type irradiator must have a source position indicator that indicates when the sources are in the fully shielded position, when they are in transit, and when the sources are exposed.

(3) The control console of a panoramic or beam-type irradiator must have a control that promptly returns the sources to the shielded position.

(4) Each control for a panoramic or beam-type irradiator must be clearly marked as to its function.