Hi All,
Diablo Canyon response is:
1. At what level of frisker reading or proportional counter reading--converted
to uCi/cc--is gamma spectroscopy of an air sample filter required? We gamma
spec all particulate air samples that are >= 0.1 DAC Beta-Gamma by field
counting. We do this because of our significant Radon background and as part
of our Alpha program. We have a correlation factor that enables us to rapidly
provide a conservative beta-gamma and alpha DAC using the gamma spec results.
We gamma spec and perform follow-up analysis on all air samples in Alpha level
3 areas regardless of field count results.
2. Do you have a minimum required air sample volume? If so, what is it? We
prefer 30 Ft3 if job conditions allow. We can have MDA challenges below that
number, depending on the analysis instrument.
3. Do you screen some or all air sample filters by frisker in the field to
determine whether other types of counting are needed? All particulate air
samples are beta-gamma screened in the field. Alpha screening at the time of
air sample is pointless for us due to high Rn background.
4. Do you see agreement between frisker, proportional counter, and gamma spec
results for air samples--in terms of uCi/cc? In terms of DAC fraction? After
correcting for hard to detects and allowing for Radon decay we see fairly good
agreement.
5. Do you use 0.1 cpm/dpm as your frisker efficiency in all situations? Yes,
for beta-gamma friskers.
If you have any questions, please contact me.
Thanks,
Linda
Linda M. Sewell, CHP
Principal Health Physicist
Pacific Gas & Electric Company
Diablo Canyon Power Plant
MS 119/1/117
PO Box 56
Avila Beach, CA 93424
P: 805.545.4315 | F: 805.545.2618| [email protected]<mailto:[email protected]>
From: [email protected] [mailto:[email protected]] On Behalf Of
Thomas J Vandermey
Sent: Thursday, March 19, 2015 7:50 AM
To: [email protected]
Subject: Powernet: quick air sample questions
Fermi 2 is revising its air sampling procedure and would like some quick
feedback:
1. At what level of frisker reading or proportional counter reading--converted
to uCi/cc--is gamma spectroscopy of an air sample filter required?
2. Do you have a minimum required air sample volume? If so, what is it?
3. Do you screen some or all air sample filters by frisker in the field to
determine whether other types of counting are needed?
4. Do you see agreement between frisker, proportional counter, and gamma spec
results for air samples--in terms of uCi/cc? In terms of DAC fraction?
5. Do you use 0.1 cpm/dpm as your frisker efficiency in all situations?
Thanks in advance!
Tom VanderMey, CHP
Principal Radiological Engineer
DTE Energy, Fermi 2
734-586-1539
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