Health Physics Questions and Answers - Question 420

Question 420: This question refers to the answer to Question 55 in §20.2104.

(a) Despite the quoted reference, §20.2104 only refers to occupational radiation dose (why radiation when the defined term is occupational dose?), which is defined in terms of "dose."

(b) The definition of dose does not include eye, shallow, or extremity doses. What is the regulatory basis for including eye, shallow, and extremity doses within the scope of §20.2104 where it is so explicitly not included? A simple discussion in the Statement of Considerations does not seem to be an adequate basis for rewriting a regulation.

(c) Are the dose histories of these three organs (eye, skin, extremity) so high as to necessitate the paperwork to track these for new employees? I suspect that for the vast majority of workers, these are negligible compared to TEDE.

Answer:

(a) "Dose" and "radiation dose" are synonymous (see "Dose or radiation dose" in §20.1003); therefore, "occupational dose" and "occupation radiation dose" are synonymous.

(b) Contrary to the statement in the question, "dose or radiation dose" is broadly defined in Part 20 as "a generic term that means absorbed dose, dose equivalent, effective dose equivalent, committed dose equivalent, committed effective dose equivalent, or total effective dose equivalent, as defined in other paragraphs of . . . [10 CFR 20.1003]." The "eye dose equivalent" and the "shallow dose equivalent" (the quantity used in the limits for the skin and for the extremities) are both "dose equivalent" quantities and, therefore, are "doses" as defined in Part 20. The occupational dose limits include limits for the eye, shallow, and extremity doses and the "occupational dose" in 10 CFR 20.2104 (a) (1) includes the eye, shallow, and extremity doses. The recommendation in the Statement of Considerations (which is not an explicit requirement in the regulation) that, in establishing administrative controls, the licensee should reduce the values for limits other than the TEDE by one quarter of their annual limit for each unreported quarter provides a method, acceptable to the NRC staff, for licensees to demonstrate compliance with those limits when records of those doses are missing for a portion of the year.

(c) A licensee is required to determine a particular occupational dose received by a new employee earlier in the current year only if the licensee makes the prospective determination that individual monitoring will be required, pursuant to 10 CFR 20.1502, for the prospective occupational dose. If the licensee determines that individual monitoring for eye or shallow or extremity dose are not required for a particular individual (because, at the licensee's facility, those doses are not likely to exceed 10 percent of the limits for those doses), the licensee is not required to determine the prior eye or shallow or extremity doses.

(References: 10 CFR 20.2104, 10 CFR 20.1003)