United States Nuclear Regulatory Commission - Protecting People and the Environment

Health Physics Questions and Answers - Question 390

Question 390: During 1993, there may be radiation workers transiting between licensees that have, and have not, implemented the revised Part 20.

(a) In the case of a worker whose dose was monitored earlier in the year at a licensee that has implemented the revised Part 20 and is now in processing at a licensee that has not implemented the revised Part 20: (1) Should "whole body dose" be taken as the "total effective dose equivalent" (TEDE) or as the "deep dose equivalent" (DDE) recorded by the previous licensee? (2) If the individual has received dose in excess of an "old" Part 20 limit for the current quarter, but less than the respective revised Part 20 limit for the year (e.g., shallow dose equivalent to an extremity of 20 rems for both the current quarter and year to date), is the individual unavailable for any further exposure in that dose category for the remainder of the quarter? (3) If the individual has received dose in excess of the "implied annual limit" of the "old" Part 20, but less than the respective annual limit in the revised Part 20 (e.g., shallow dose equivalent to the skin of 35 rems in the current quarter and year to date), is the individual unavailable for further exposure in that dose category for the remainder of the year? (4) If the individual has received a planned special exposure (PSE) at the previous workplace in the current quarter, how should the PSE dose be accounted for as prior occupational dose by the present licensee under the "old" Part 20? Should the PSE dose be subtracted from the available current quarter dose for that dose category?

(b) In the case of a worker whose dose was monitored earlier in the year at a licensee that has not implemented the revised Part 20 and is now inprocessing at a licensee that has implemented the revised Part 20: if the individual has received recorded internal dose (in terms of rem) or internal exposure (in terms of MPC-hrs) or internal uptake (in terms of organ burden), how should this data be considered with regard to revised Part 20 requirements (i.e., TEDE, CEDE, or CDE)?

Answer:

(a) (1) DDE. (2) Yes, the individual is "unavailable for any further exposure in that dose category for the remainder of the quarter" because the individual has already exceeded the applicable dose limit for the quarter. (3) The individual is unavailable for further exposure in that dose category for the remainder of the quarter (because the individual has exceeded the applicable dose limit for the quarter), but is available for further exposure in that dose category for the remainder of the year after the end of the quarter. (4) The PSE dose should be accounted for as occupational dose received during the quarter and should be subtracted from the available current quarter dose for the dose category.

(b) CEDE.

(Reference: 10 CFR 20.2104)

Page Last Reviewed/Updated Wednesday, October 07, 2015