Health Physics Questions and Answers - Question 444
Question 444: In this example, it has been determined that an individual will receive less than 100 mrems in a year while in the controlled area, and the individual has therefore been classified as a member of the public while in the controlled area. The individual also accesses and performs work in the restricted area. In evaluating whether the individual requires monitoring in the restricted area, may the evaluation be limited to only the dose likely to be received in the restricted area, i.e., may the potential dose received in the controlled area be disregarded for the purpose of the evaluation?
Answer: The answer to the question is yes, assuming that the basis for classifying the individual as a member of the public while in the controlled area is the type of work the individual will do in the controlled area.
As emphasized in the answer to Question 26 (a), whether the dose to an individual outside a restricted area is an occupational dose or a public dose depends on what the individual is doing and not on what area (controlled or unrestricted area) the individual is in when the dose is received. Furthermore, it is possible, and acceptable (as indicated in many previous questions and answers), for the licensee to consider the dose (other than background, etc.) that individual receives in a controlled area to be an occupational dose, even though, as stated in the question, the dose the individual receives in the controlled area is less than 100 mrem per year. Regardless of the magnitude of the dose, the dose is an occupational dose if it is received (in accordance with the definition of occupational dose) ". . . in the course of employment in which the individual's assigned duties involve exposure to radiation and to radioactive material . . ." For example, an individual who performs a radiation survey, in any area, of a vehicle loaded with radioactive material prepared for shipment would be receiving an occupational dose as a result of exposure to the radiation from the radioactive material on the vehicle regardless of the magnitude of the dose. However, the dose (other than background, etc.) received by a worker performing office work in a controlled area could be considered to be either an occupational dose or a public dose; either choice would be considered to be consistent with the definition of "occupational dose." See Question 26 and answer for additional information concerning licensee options with respect to area designations and dose categories. See Question 126 concerning the use individual monitoring of occupational doses from effluents.
(References: 10 CFR 20.1502, 10 CFR 20.1003)