Tritium activities in water vapor and radioactive carbon (14C) activities in carbon dioxide were determined in gas samples pumped from small-diameter air ports installed in a test hole within the unsaturated sediments next to a commercial burial site for low-level radioactive waste south of Beatty, Nevada. In April 1994, gas samples were collected from test hole UZB-2, which was drilled about 350 feet south of the southwest corner of the fence enclosing the burial site. The test hole is part of a study to determine the depth to which atmospheric air circulates through the unsaturated sediments at the desert site. Laboratory results completed in May 1995 show activities of tritium and 14C were greater than expected, with measured tritium in the water vapor as high as 762 tritium units at a depth of 79 feet and measured 14C in carbon dioxide as high as 1,700 percent modern carbon at a depth of 18 feet. In July 1995, the uppermost five air ports in test hole UZB-2 were resampled. In addition, water vapor was collected for tritium analyses at a distant test hole, and water vapor for tritium analyses and carbon dioxide for 14C analyses were collected from three depths at the research shaft about 200 feet north of test hole UZB-2, and at two shallow probes (depth of 5.5 feet) next to the fence enclosing the burial site. Analyses of samples collected in the upper 112 feet from test hole UZB-2 in July 1995 show the same distribution of tritium and 14C as analyses of samples collected in April 1994, except that activities were somewhat greater in July. The greatest activities of tritium and 14C were measured from a shallow probe next to the fence with activities of 29,400 tritium units and 517,000 percent modern carbon, respectively.
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Tritium and radioactive carbon (14C) analyses of gas collected from unsaturated sediments next to a low-level radioactive-waste burial site south of Beatty, Nevada, April 1994 and July 1995
U.S. Dept. of the Interior, U.S. Geological Survey ;
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