“Personnel monitoring for external exposure shall be performed on all occupationally exposed individuals who may receive >25% of the applicable MPD during the normal course of their duties or through accidental exposure.”

Personnel monitoring is not required where the nature of the work performed or the nature of the radiation sources is such that personnel exposures are below the limits recommended for uncontrolled areas and where there is very small potential for accidental exposure above these limits.

Occasional visitors to controlled areas, including messengers, servicemen, and deliverymen should be regarded as non-occupationally exposed persons since it is most improbably that they will receive in one year a dose equivalent exceeding the non-occupational limit of 0.5 Rem during their brief time in controlled areas. They therefore do not need to be badged.

Long term visitors to controlled areas should be regarded as occupationally exposed persons if it is likely that they will receive a dose equivalent exceeding 0.5 Rem per year. They should be monitored according to the criteria of "Occupationally Exposed Persons" above.

• The ideal personnel monitoring device must accurately measure the biological dose in Rems received by parts of the body considered to be most vital from the standpoint of  chronic low level exposure, i.e., bone marrow and gonads.

• Measurement must be independent of type and energy of radiation producing the dose.

Records must be continuously maintained and 
preserved in accordance with CFR 20.401(c) 
until NRC authorizes disposition.