Health Physics Questions and Answers - Question 400

Question 400: NRC Form 5 (Item No. 10B) includes the symbol "V", which is not defined in Regulatory Guide 8.7, Revision 1.

(a) Does the "V" signify "vapor" as used in Federal Guidance Report No. 11?

(b) If so, how is this lung clearance class to be applied in operational air sampling and internal dosimetry programs?

Answer:

(a) "V" in Item 10B of Form 5 is an abbreviation for the lung clearance class "vapor" in Appendix B to 10 CFR 20.1001 - 20.2401. "Vapor" is listed as a lung clearance "class" for only two elements, sulfur and nickel. (However, the "water" inhalation class for hydrogen-3 indicates water vapor.)

(b) The "vapor" inhalation class should be used when the radionuclides are present in the form of a vapor in the air and the associated air sampling should be appropriate for sampling the radionuclides in this form.

(References: 10 CFR 20.2106, 10 CFR 20.2206, Regulatory Guide 8.7)