United States Nuclear Regulatory Commission - Protecting People and the Environment

U.S. Nuclear Regulatory Commission

Question 126: Individuals performing assigned duties are

often exposed to small amounts of radiation from plant

effluents at licensees' sites under normal operating

conditions. (a) If these individuals are likely to

receive, or have already received, in excess of 10% of an

occupational dose limit from external sources, does the

licensee have to determine, record, and report doses from

the effluents to comply with the revised Part 20? (b) If

so, what are the monitoring thresholds for the external and

internal components of the dose?

Answer: (a) Yes. In this case, the licensee would have

to monitor and record the external dose from the effluents,

since the individuals are in excess of 10% of the

occupational dose limit from all external sources 20.1502

(a)). However, the licensee is not required to monitor the

effluent dose separately from other external doses.

(b) The licensee must monitor and record the internal

occupational dose only if the individuals are likely to

receive in excess of 10% of the applicable ALIs from all

occupational intakes of radioactive material. Note: For

nuclear power plants, the preceding answer does not mean

that all workers for whom monitoring of external dose is

required must wear their personal dosimeters at all times

while on site. Such workers in controlled areas (outside

restricted areas) need not wear personal dosimeters to

measure external doses from effluents. However, they

should wear personal dosimeters in a controlled area when

performing work that has the potential for significant

occupational exposure such as performing a radiation survey

of a vehicle loaded with a shipment of radioactive

material. (Reference: 10 CFR 20.1502)

Page Last Reviewed/Updated Thursday, March 29, 2012