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?
(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)