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U.S. Department of Energy
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Selenite transport in unsaturated tuff from Yucca Mountain

Conference ·
OSTI ID:60952
 [1];  [2]
  1. WSU Tri-Cities, Richland, WA (United States)
  2. Los Alamos National Lab., NM (United States)

Direct measurements of unsaturated selenite retardation coefficients and unsaturated hydraulic conductivity were obtained on two tuff samples from Yucca Mountain using the UFA{trademark} technology. The retardation factor for the selenite species was only 2.5 in both Yucca Mountain vitric member at 62.6% saturation and zeolitized nonwelded tuff from G-tunnel at 52.8% saturation with respect to J-13 well water from the Nevada Test Site contaminated with selenium at 1.31 mg/l (ppm). In batch tests on the same material using 1.2 mg/l (ppm), the average K{sub d} was determined to be 13, giving retardation factors higher than the UFA column breakthrough tests by an order of magnitude. The difference could result from preferential flow paths in the UFA column as might occur in the field or differences in residence times between the two types of tests. The unsaturated hydraulic conductivities during the experiments were 2.49 {times} 10{sup {minus}8} cm/s for the Yucca Mountain vitric member and 1.16 {times} 10{sup {minus}8} cm/s for the zeolited nonwelded tuff.

Research Organization:
American Society of Civil Engineers, New York, NY (United States); American Nuclear Society, La Grange Park, IL (United States)
OSTI ID:
60952
Report Number(s):
CONF-940553--Vol.4
Country of Publication:
United States
Language:
English