Health Physics Questions and Answers - Question 218
Question 218: 10 CFR 20.1601 (a) (1) says that the control devices must cause the radiation level to be reduced "upon entry."
(a) Must the devices preclude authorized or unauthorized entry?
(b) At what point must the control devices activate, when a person passes the final 30 cm before, or entry itself?
(a) 10 CFR 20.1601 (a) requires that entrance or access points to a high radiation area have "one or more" of the listed features to preclude excessive radiation exposure to an individual. The control device in subparagraph (1) stipulates only that it cause the radiation level to be reduced so that an individual, upon entry, could not receive 100 mrem in an hour within 30 cm of an accessible area of the source. This paragraph does not distinguish between "authorized" or "unauthorized."
(b) The control device must activate "upon entry into the area" at the "entrance or access point."
(Reference: 10 CFR 20.1601)