1. At what level of frisker reading or proportional counter reading--converted to uCi/cc--is gamma spectroscopy of an air sample filter required? Historically, we’ve done a HPGe count if the measured DAC fraction was > 0.3 DAC & looked for the radon & daughter peaks as well as any plant radionuclides. Our current procedures (Exelon RP-AA-301) have an option of using a HPGe count to estimate the alpha using a Co-60 to alpha ratio.
2. Do you have a minimum required air sample volume? If so, what is it? 110 cu-ft. That is driven by our instrument LLDs and default alpha DAC (Am-241) 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 ours get counted on a gas-proportional counter. 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? It depends on the radionuclide mix for the location. If mostly activation products, then the correlation is very good. In in a high alpha area and some areas with significant fission products (e.g., Cs-137, Sr/Y-90, etc.), then not so much. 5. Do you use 0.1 cpm/dpm as your frisker efficiency in all situations? As a field thumb rule, yes. David Brehm Radiological Engineer Radiation Protection – Nuclear Operations Omaha Public Power District - Fort Calhoun Nuclear Station 9610 Power Lane, Blair, NE 68008 Office: 402.533.7582 Cellular: 402.237.9840 [email protected]<mailto:[email protected]> SCIENCE: ruining everything since 1543 ---------------------------------------------------------------------- This e-mail contains Omaha Public Power District's confidential and proprietary information and is for use only by the intended recipient. Unless explicitly stated otherwise, this e-mail is not a contract offer, amendment, or acceptance. If you are not the intended recipient you are notified that disclosing, copying, distributing or taking any action in reliance on the contents of this information is strictly prohibited.
