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A Rugged Continuous Air Monitor for Sampling Radionuclides
Abstract
A new rugged continuous air monitor (CAM) for sampling radionuclide has been developed. The sampler was designed for analyzing aerosols from occupied environments of laboratories and samples extracted from stacks and ducts. Experiments were conducted to characterize the collection efficiency of the aerosol sampler system and to characterize the uniformity of particulate deposition on the filter surface as affected by variations in particle size and sampler flow rates. An experimental parametric analysis was conducted to determine the best internal geometric flow configuration, in order to achieve optimum aerosol collection. The results showed that at a flow rate of 56.6 L/min, 90% of 10 []m aerodynamic diameter (AD) aerosol particles penetrated through the sampler. The 10% loss was attributed to particle impaction at the location where the aerosol stream is turned from the vertical direction and then enters a 4 mm gap between a sampler filter and a planar detector, both of which are horizontally oriented. The cut point for the sampler was 20 []m AD. Uniformity of aerosol collection on the filter, as characterized by the coefficient of variation of the areal density deposits, was less than 10% for 10 []m AD aerosol particles. The sampler sealing integrity with respect to air leaks was tested by placing the sampler in a pressurized container and operating the sampler with the pressure in the container higher than that in the sampler for in-leakage, and with the pressure in the container less than that in the sampler for out-leakage. The pressure inside the container did not exceed 10 inches of water. For in-leakage tests, sulfur hexafluoride (SF₆) was diluted with air and released into the container, external to the sampler. The ratio of the SF₆ concentration in the sampler to the SF₆ concentration in the container was calculated to characterize the integrity of the sampler system. For pressure differences of 5 and 10 inches of water, the in-leakage was 0.03% and 0.02%, respectively. The same procedure was repeated for out-leakage except that the diluted SF₆ was released into the sampler. The leakage results for this procedure were 0.04% and 0.02% for pressure differences of 5 and 10 inches of water, respectively.
Description
Due to the character of the original source materials and the nature of batch digitization, quality control issues may be present in this document. Please report any quality issues you encounter to digital@library.tamu.edu, referencing the URI of the item.Includes bibliographical references (leaves 41-43).
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Citation
Martinez, Joseph Thaddeus (2002). A Rugged Continuous Air Monitor for Sampling Radionuclides. Master's thesis, Texas A&M University. Available electronically from https : / /hdl .handle .net /1969 .1 /ETD -TAMU -2002 -THESIS -M37.
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