Health Physics Questions and Answers - Question 461

Question 461: Does the word "applicable" in the phrase "applicable ALI (s)" in 10 CFR 20.1502 (b) (1) mean that the stochastic ALI (s) [SALI (s)] should be used?

It is noted that 10 CFR 20.1502 (b) requires the licensee to monitor the occupational intake and assess the committed effective dose equivalent. We believe that the answer to this question should be yes, if a licensee is operating under the "more limiting" dose limit of 5 rem TEDE. The occupational dose limits in 10 CFR 20.1201 apply to the "more limiting" of 5 rem TEDE or 50 rem TODE. If a licensee's prospective assessment shows that the exposure conditions at their facility is most likely to be limited by the 5 rem TEDE limit, then the "applicable" ALI is the SALI. This is further shown by the wording used in 10 CFR 20.1502 (b); i.e., use of the "committed effective dose equivalent" terminology.

Answer: No, not necessarily. The "applicable" ALI is the ALI for the appropriate radionuclide, the appropriate column (inhalation or ingestion), and, for inhalation ALIs, the appropriate "class" (D, W, or Y). When both a stochastic and a non-stochastic inhalation ALI are listed for a particular radionuclide (e.g., for I-131), the "applicable ALI" in 10 CFR 20.1502 (b) means the more limiting ALI, which is listed first (the non-stochastic ALI), not the stochastic ALI, which is listed second and is shown in parentheses. The statements made by the questioner following the question are not relevant to the question.

(Reference: 10 CFR 20.1502).