Health Physics Questions and Answers - Question 122

Question 122: The conforming amendment to 10 CFR 50.73 (a) (2) states that reports submitted in accordance with 10 CFR 50.73 (a) (2) (viii) also meet the effluent release reporting requirements of 10 CFR 20.2203 (a) (3). However, 10 CFR 20.2203 (a) (3) requires reporting of concentrations in an unrestricted area of 10 times any applicable limit in Part 20 while 10 CFR 50.73 (a) (2) (viii) requires reports of airborne or liquid effluent releases that exceed 20 times the applicable concentration limits in Table 2, Appendix B. Why is the multiple ten in one case and twenty in the other?

Answer: The two reporting requirements are consistent in terms of public dose. The annual dose limit for a member of the public is 100 mrem. 10 CFR 20.2203 (a) (3) requires reporting above a threshold of ten times this applicable limit, or 1000 mrem. The concentrations in Table 2, Appendix B, correspond to an annual dose of 50 mrem; therefore, the requirement in 10 CFR 50.73 (a) (2) (viii) for reporting at 20 times these concentrations corresponds to a reporting threshold in terms of annual dose, of 20 x 50 mrem, or 1000 mrem, which is the same dose threshold as that in 10 CFR 20.2203 (a) (3).

(References: 10 CFR 20.2203, 50.73)