Exelon recently purchased the RADeCO RAD-Pro 5. Neat little units however, it
has an automatic internal self-adjustment feature that causes the unit to turn
off for up to 10 seconds when there is a temperature change of more than 3ºC.
This caused some confusion at Dresden when we first started using them. Once
the feature was understood, we have not had any other real issues.
Exelon is in the approval process for a transuranic dose tracking procedure
(using lapel sampling of course). If you are interested in a draft copy let me
know and I will send it to you directly.
The remainder of this e-mail is my personal thoughts and not necessarily
reflective of Exelon's position/opinions.
My experience with lapel air sampling, at both transuranic waste facilities and
in EPRI Level 3 alpha areas, compels me to point out that the real difficulty
with lapel air sampling programs is not really which sampler to use but
how/what to do with the data. The intent and techniques used for lapel air
sampling are often misunderstood. To that point, I offer the following:
* Consider that an ED, a frisker, a TLD, a fission chamber, an ion
chamber, etc.... all detect radiation but they are designed to serve different
needs.
* Think of the job coverage air sample (grab sample) like a dose rate
meter; they are both used to assess the working conditions.
* Think of a lapel air sample like you would an ED; they both are
intended to measure accumulated dose.
* You would not use an ED to determine proper posting for an
area. By the same convention, you should not use a lapel sampler to determine
proper postings. The right tool for posting determination is a grab sampler.
* Do not attempt to calculate a DAC from a lapel. It confuses
people as to what the real intent is and they (mistakenly) believe that the air
sample has no point since they can not realistically prove an area is < 0.3 DAC
(because there is such a low volume collected). Instead, directly calculate
the (potential) intake from the activity on the filter and the flow-rate the
lapel is operating at. This intake can be directly converted to dose using
standard FGR-11 dose conversion factors.
* While performing lapel air sampling, it is perfectly acceptable
(and desirable) to use the same lapel air sample (on the same person of course)
for the whole shift. You can even turn them off during break periods because
the total volume is not important to the calculation. Only the flow rate and
activity on the filter is necessary.
I am sure that there are differing opinions out there. If anyone would like to
see a hypothetical example of how this monitoring/calculation would play out
(from my perspective) let me know. I can send you a scenario directly as well.
Cheers,
Jeffrey J. Cady, CHP, RRPT
Mgr RP Technical Support
Exelon Nuclear
Dresden Station
6500 North Dresden Road
Morris, IL 60450-9765
Phone: (815) 416-2719
[email protected] <mailto:[email protected]>
________________________________
From: [email protected] [mailto:[email protected]] On Behalf Of
Barnby, Monica
Sent: Monday, November 07, 2011 10:41 AM
To: '[email protected]'
Subject: Powernet: Lapel Air Sampling
All,
Do you use personal lapel air samplers?
If so, what make/model? Advantages/disadvantages?
At DCPP we do not use personal lapel samplers.
Thanks!
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