Email RIS file
Bookmark
Report an Issue

Analysis of Radionuclide Migration Through a 200-m Vadose Zone Following a 16-Year Infiltration Event [electronic resource].

Published
Washington, D.C. : United States. Dept. of Energy, 2002.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy.
Physical Description
PDF-FILE: 27 ; SIZE: 3.6 MBYTES pages
Additional Creators
Lawrence Livermore National Laboratory, United States. Department of Energy, and United States. Department of Energy. Office of Scientific and Technical Information
Access Online

Availability

I Want It
I Want It

Finding items...

Restrictions on Access
Free-to-read Unrestricted online access
Summary
The CAMBRIC nuclear test was conducted beneath Frenchman Flat at the Nevada Test Site on May 14, 1965. The nuclear device was emplaced in heterogeneous alluvium, approximately 70 m beneath the ambient water table, which is itself 220 m beneath the ground surface. Approximately 10 years later, groundwater adjacent to the test was pumped steadily for 16 years to elicit information on radionuclide migration in the saturated zone. The pumping well effluent--containing mostly soluble radionuclides such as tritium, ¹⁴C, ³⁶Cl, ⁸⁵Kr, ¹²⁹I, and ¹°⁶Ru--was monitored, discharged to an unlined ditch, and allowed to flow towards Frenchman Lake just over one kilometer away. Water discharged into the ditch infiltrated into the ground during flow along the ditch. This created an unexpected and remarkable second experiment in which the migration of the effluent through the 220 meters of unsaturated media, or ''vadose zone'', back to the water table, could be studied. In this paper, the pumping and effluent data are being utilized in conjunction with a series of geologic data, new radionuclide measurements, isotopic age-dating estimates, and vadose zone flow and transport models to better understand the movement of radionuclides between the ditch and the water table. Measurements of radionuclide concentrations in water samples produced from a water table monitoring well 100m away from the ditch indicate rising levels of tritium since 1993. The detection of tritium in the monitoring well occurs approximately 16 years after its initial discharge into the ditch. Modeling and tritium age dating have suggested 3 to 5 years of this 16-year transit time occurred solely in the vadose zone. They also suggest considerable recirculation of the pumping well discharge back into the original pumping well. Surprisingly, no ¹⁴C was observed at the water table, suggesting its preferential retention, possibly due to precipitation or other chemical reaction, during transit to the water table. Overall, the long term nature of the experiment, the variety of chemical measurements and isotopic interpretations, and their incorporation into a unified modeling analysis, have contributed to a unique perspective for interpreting radionuclide migration in the unsaturated zone.
Report Numbers
E 1.99:ucrl-id-146979
ucrl-id-146979
Subject(s)
Other Subject(s)
Note
Published through SciTech Connect.
01/31/2002.
"ucrl-id-146979"
Smith, D K; Tompson, A F B; Hudson, G B.
Funding Information
W-7405-ENG-48
View MARC record | catkey: 14136763