Effects of Weathering on Impregnated Charcoal Performance.
NAVAL RESEARCH LAB WASHINGTON DC
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The useful life of activated carbon filters in engineered safety-feature and normal ventilation systems of nuclear power stations is slowly impaired by the contaminants accumulated from the large volume of air in process. In this study eight commercial impregnated carbons were exposed to unmodified outdoor air at NRL for different periods up to one year and to air flows of known contaminant species and concentrations under controlled laboratory conditions, both followed by measurements of the methyl-iodide-131 penetration. Two of the carbons were exposed to outdoor air at the Argonne National Laboratory and at the Simi Valley Monitoring Station. The test carbons included commercial impregnations of potassium iodide with or without elemental iodine and of tertiary amines, either separately or as co-impregnates. Air flows above 70 RH degrade the carbon efficiency significantly. Also, an adverse synergistic influence of moisture and hydrocarbon vapors has been observed. The entrance layer of test charcoals were found to be most significantly affected by the exposure insult. The gradient in methyl iodide-131 penetration through the bed changes from a simple exponential profile for new carbons to a non-linear exponential profile for weathered and service-aged carbons.
- Pumps, Filters, Pipes, Tubing, Fittings and Valves
- Nuclear Power Plants and Fission Reactor Engineering