A modeling study of contaminant transport resulting from flooding of Pit 9 at the Radioactive Waste Management Complex, Idaho National Engineering Laboratory [electronic resource].
- Washington, D.C. : United States. Dept. of Energy, 1992. and Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy.
- Physical Description:
- 40 pages : digital, PDF file
- Additional Creators:
- United States. Department of Energy and United States. Department of Energy. Office of Scientific and Technical Information
- A simulation study was conducted to determine if dissolved-phase transport due to flooding is a viable mechanism for explaining the presence of radionuclides in sedimentary interbeds below the Radioactive Waste Management Complex. In particular, the study focused on ²⁴¹Am migration due to flooding of Pit 9 in 1969. A kinetically-controlled source term model was used to estimate the mass of ²⁴¹Am that leached as a function of a variable surface infiltration rate. This mass release rate was then used in a numerical simulation of unsaturated flow and transport to estimate the advance due to flooding of the ²⁴¹Am front down towards the 110 ft interbed. The simulation included the effect of fractures by superimposing them onto elements that represented the basalt matrix. For the base case, hydraulic and transport parameters were assigned using the best available data. The advance of the ²⁴¹Am front due to flooding for this case was minimal, on the order of a few meters. This was due to the strong tendency for ²⁴¹Am to sorb onto both basalts and sediments. In addition to the base case simulation, a parametric sensitivity study was conducted which tested the effect of sorption in the fractures, in the kinetic source term, and in the basalt matrix. Of these, the only case which resulted in significant transport was when there was no sorption in the basalt matrix. The indication being that other processes such as transport by radiocolloids or organic complexation may have contributed. However, caution is advised in interpreting these results due to approximations in the numerical method that was used incorporate fractures into the simulation. The approximations are a result of fracture apertures being significantly smaller than the elements over which they are superimposed. The sensitivity of the ²⁴¹Am advance to the assumed hydraulic conductivity for the fractures was also tested.
- Published through SciTech Connect., 09/01/1992., "egg-eel--10498", "DE93016668", Magnuson, S.O.; Sondrup, A.J., and EG and G Idaho, Inc., Idaho Falls, ID (United States)
- Type of Report and Period Covered Note:
- Topical; 09/01/1992 - 09/01/1992
- Funding Information:
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