NukeWorker Forum
Career Path => Radiation Safety => Topic started by: kp88 on Apr 28, 2009, 08:52
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10CFR20 actually defines an intake class as:
Class (or lung class or inhalation class) means a classification scheme for inhaled material according to its rate of clearance from the pulmonary region of the lung. Materials are classified as D, W, or Y, which applies to a range of clearance half-times: for Class D (Days) of less than 10 days, for Class W (Weeks) from 10 to 100 days, and for Class Y (Years) of greater than 100 days.
The instructions for filling out an NRC-5 state:
Enter the lung clearance class as listed in Appendix B to 10CFR Part 20.1001-2401 (D, W, Y, V, F, M, S, or O for other) for all intakes by inhalation.
Does anybody know what in the heck V, F, M, and S mean?
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The latest instructions that I can find state: "Enter the lung clearance class as listed in Appendix B to 10 CFR Part 20.1001-2401 (D, W, Y, V, or O for other) for all intakes by inhalation."
A CHP at work told me that F, M, and S are obsolete classes. Each class is based on the chemical compounds and the radiological half-life. If the chemical compound changes, the clearance class can change even for the same radioisotope. When you have a mixture of these compounds, your class becomes variable (i.e., V) based on the attendant concentrations.
Other, or O, is when the compound that you are dealing with does not fall within the defining parameters of D, W, or Y. He's supposed to be finding a reference for this explanation. When he does , I'll post it.
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Thanks Mo. I've been looking through my internal dosimetry stuff and was unable to find the definitions. I hate when I can't find that kind of stuff.
LM
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The latest instructions that I can find state: "Enter the lung clearance class as listed in Appendix B to 10 CFR Part 20.1001-2401 (D, W, Y, V, or O for other) for all intakes by inhalation."
Strangely enough, the Form 5 in the Reg Guide that I found on REIRS lists only W, Y, V, or O. The Form 5 on the NRC site lists all the classes.
I found this on the NRC web site.
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).
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F, M & S are Fumes, Mists, and Solids.
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the only forms i've used the past couple of years were written in 2001 and the OMB approval (upper right corner) expired in 2004--maybe they are all invalid.
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the only forms I've used the past couple of years were written in 2001 and the OMB approval (upper right corner) expired in 2004--maybe they are all invalid.
Actually, the NRC 4 & 5 got revised 11/08. Apparently all they changed was estimate dose is now preliminary dose, as near as I can tell. They also seem to have gotten rid of some of the inhalation classes in the explanations on the back of the forms.
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Actually, the S may stand for smoke.
The terms "vapor", "mists", "fumes", and "smoke" are all closely related and sometimes one may contain one or more of the others as well as dust or other solids and gasses.
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F, M and S are "Fast", "Medium" and "Slow" which are more current descriptions of inhalation classes than the D, W, and Y.
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F, M and S are "Fast", "Medium" and "Slow" which are more current descriptions of inhalation classes than the D, W, and Y.
I think that I'll go along with fumes, mist, and smoke.
10CFR20.1003 Definitions
Airborne radioactive material means radioactive material dispersed in the air in the form of dusts, fumes, particulates, mists, vapors, or gases.
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10CFR20 actually defines an intake class as:
Class (or lung class or inhalation class) means a classification scheme for inhaled material according to its rate of clearance from the pulmonary region of the lung. Materials are classified as D, W, or Y, which applies to a range of clearance half-times: for Class D (Days) of less than 10 days, for Class W (Weeks) from 10 to 100 days, and for Class Y (Years) of greater than 100 days.
The instructions for filling out an NRC-5 state:
Enter the lung clearance class as listed in Appendix B to 10CFR Part 20.1001-2401 (D, W, Y, V, F, M, S, or O for other) for all intakes by inhalation.
Does anybody know what in the heck V, F, M, and S mean?
10CFR20 Appendix B:
" ... and classes (D,W,Y) of radioactive material, which refer to their retention (approximately days, weeks or years) in the pulmonary region of the lung."
I think that I'll go along with fumes, mist, and smoke.
10CFR20.1003 Definitions
Airborne radioactive material means radioactive material dispersed in the air in the form of dusts, fumes, particulates, mists, vapors, or gases.
This defines airborne radioactive material, which is all well and good. However, I only see mention of forms (which distinguish between physical differences); I don't see any mention of classes (which distinguish between retention/clearance times in the pulmonary region of the lung).
I'm not saying that "Fast/Medium/Slow" are correct answers, because I can't cite a valid reference. However, I would certainly rule out "Fumes/Mists/Smoke" as classes, because they don't specify retention/clearance times in the pulmonary region of the lung as required by 10CFR20 Appendix B.