[ RadSafe ] lapel monitors for potential airborne alpha particulates

Glenn R. Marshall GRMarshall at philotechnics.com
Fri Jul 30 07:50:25 CDT 2010

Regulations and guidance documents all specify air sampling, when performed to monitor potential internal exposures, be representative of the air the worker is breathing--without respiratory protection.  So in most cases, a lapel sampler is indicated.  One exception is, say if the worker is removing the contents of a drum; in that case, a fixed air sampler above the drum and next to the worker is probably acceptable.  

Workers hate wearing lapel samplers, and most HPs hate dealing with them.  And if the contaminant is transuranic or thorium, there are problems with meeting the required MDA because the sample volume isn't large enough.  NRC Information Notice 96-18, "Compliance with 10 CFR Part 20 for Airborne", discusses this in detail.  Urine bioassay may not detect small fractions of the ALI for some of these radionuclides, and fecal samples are not pleasant.  So an air sampling program that can detect small fractions of the ALI, combined with bioassay and a robust ALARA analysis, is mandatory.

Also, NUREG 1400 has some guidance in the appendix for estimation of a time-weighted MDA if you are collecting multiple samples over a long period of time.  Use of those equations will help in meeting detection limits.

Glenn Marshall, CHP, RRPT

-----Original Message-----
From: radsafe-bounces at health.phys.iit.edu [mailto:radsafe-bounces at health.phys.iit.edu] On Behalf Of JOHN.RICH at sargentlundy.com
Sent: Thursday, July 29, 2010 10:38 PM
To: radsafe at health.phys.iit.edu
Subject: [ RadSafe ] lapel monitors for potential airborne alpha particulates


It has been suggested that D&D workers use lapel monitors for potential 
airborne alpha particulates IN ADDITION TO a continuous air sampler in the 
immediate vicinity of the D&D work.

My first thought is that the nuisance factor for the workers is going to 
be "anti-ALARA."

Can anybody provide some experience with the necessity, effectiveness, and 
"value added" by lapel monitors vs an air sampler in the immediate 

Thanx in advance  - -jmr

John Rich
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