United States Nuclear Regulatory Commission - Protecting People and the Environment

U.S. Nuclear Regulatory Commission

U.S. Nuclear Regulatory Commission

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).









Page Last Reviewed/Updated Thursday, March 29, 2012