Filter Paper: Solution to High Self-Attenuation Corrections in HEPA Filter Measurements

Technical Report · Sat Oct 01 04:00:00 EDT 2005

DOI:https://doi.org/10.2172/899138· OSTI ID:899138

Oberer, R B; Harold, N B; Gunn, C A; Brummett, M; Chaing, L G

An 8 by 8 by 6 inch High Efficiency Particulate Air (HEPA) filter was measured as part of a uranium holdup survey in June of 2005 as it has been routinely measured every two months since 1998. Although the survey relies on gross gamma count measurements, this was one of a few measurements that had been converted to a quantitative measurement in 1998. The measurement was analyzed using the traditional Generalized Geometry Holdup (GGH) approach, using HMS3 software, with an area calibration and self-attenuation corrected with an empirical correction factor of 1.06. A result of 172 grams of {sup 235}U was reported. The actual quantity of {sup 235}U in the filter was approximately 1700g. Because of this unusually large discrepancy, the measurement of HEPA filters will be discussed. Various techniques for measuring HEPA filters will be described using the measurement of a 24 by 24 by 12 inch HEPA filter as an example. A new method to correct for self attenuation will be proposed for this measurement Following the discussion of the 24 by 24 by 12 inch HEPA filter, the measurement of the 8 by 8 by 6 inch will be discussed in detail.

• Research Organization: Oak Ridge Y-12 Plant (Y-12), Oak Ridge, TN
• Sponsoring Organization: USDOE - Office of Defense Programs (DP)
• DOE Contract Number: AC05-00OR22800
• OSTI ID: 899138
• Report Number(s): Y/DK-2152 Rev 1
• Country of Publication: United States
• Language: English

Related Subjects

61 RADIATION PROTECTION AND DOSIMETRY
ACCURACY
AIR FILTERS
MEASURING METHODS
RADIATION MONITORING
URANIUM 235