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).