[ RadSafe ] Stack Emission Limits

[Wesley]

Otto,
This is a question that I have come across many times.
The NRC 10 CFR 20 regulation specifies an annual average concentration, as
you state. But the critical point is that this annual average concentration
is taken at the boundary of the unrestricted area. Often this is taken at
the stack outlet, but not always.
When there is no radioactive emission, the concentration at the stack outlet
is ZERO, whether the fan is running or not! So you do not have to run the
fan all year to take advantage of the annual averaging.

Best regards,
Wes
Wesley R. Van Pelt, PhD, CIH, CHP
Wesley R. Van Pelt Associates, Inc.
Paramus and Princeton, NJ
 
-----Original Message-----
From: radsafe-bounces at radlab.nl [mailto:radsafe-bounces at radlab.nl] On Behalf
Of Otto Raabe
Sent: Wednesday, February 07, 2007 1:51 PM
To: Franz Schönhofer; RADCHEM-LIST (RADCHEM-LIST); RADSAFE
Subject: [ RadSafe ] Stack Emission Limits

February 7, 2007

10 CFR Part 20 sets annual average limitation for stack emissions in the 
United States.  For example, for carbon-11 monoxide, the annual average 
concentration is given as 2E-6 microcuries per milliliter of air. [Sorry 
about the American units.] .

My question concerns a brief ultra-high concentration emission that may 
occur only occasionally and last only a few seconds. Is there a peak limit 
for such an emission? I can always run my exhaust fans for a year to get 
the average down to the allowed annual average, but even if the exhaust 
fans were turned off after an emission event there is no real difference in 
potential exposure risk.  But it seems that I can meet the release limit by 
simply running my fans while there are no emissions.

Comments please.

Otto

**********************************************
Prof. Otto G. Raabe, Ph.D., CHP
Center for Health & the Environment
University of California
One Shields Avenue
Davis, CA 95616
E-Mail: ograabe at ucdavis.edu
Phone: (530) 752-7754   FAX: (530) 758-6140
*********************************************** 
_______________________________________________
You are currently subscribed to the RadSafe mailing list

Before posting a message to RadSafe be sure to have read and understood the
RadSafe rules. These can be found at:
http://radlab.nl/radsafe/radsaferules.html

For information on how to subscribe or unsubscribe and other settings visit:
http://radlab.nl/radsafe/