Effects of Weathering on Impregnated Charcoal Performance.
Abstract
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 being processed. The weathering of eight commercial impregnated activated carbons have now been studied by a two-fold approach: (1) Exposure to unmodified outdoor air for periods up to nine months, followed by measurements of methyl iodide-131 penetration, and (2) exposure of the same type charcoals to air flows of known pollutant species and concentrations under controlled laboratory conditions, also followed by measurements of the methyl iodide-131 penetration. The influence of moisture in laboratory air flows of 50, 70 and 90% RH has been studied in detail for the eight charcoals. The exposures of the charcoals to outdoor air have now been extended to nine months and the results show a progressive decrease in iodine trapping efficiency. There is evidence from both the laboratory and outdoor exposure tests that moisture can enhance charcoal degradation. An adverse synergistic influence of moisture and hydrocarbon vapors has also been observed. All samples were layered to permit a determination of the profile in properties along the line of flow. The entrance layer, first of four equal layers, was found to be the most significantly affected by the exposure insult. It is believed that local meteorological conditions of high humidity combined with atmospheric pollutants in the test vicinity contribute jointly to the degradation of impregnated activated carbons. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- May 10, 1979
- Accession Number
- ADA069499
Entities
People
- Victor R. Deitz
Organizations
- United States Naval Research Laboratory