ISSN:
1745-6584
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Energy, Environment Protection, Nuclear Power Engineering
,
Geosciences
Notes:
An analysis was conducted of multidimensional subsurface moisture flow in a hypothetical low-level radioactive waste disposal facility. The key design feature examined in the analysis was a sloping sand/gravel capillary barrier designed to route natural infiltration around a concrete vault. Three barrier slopes (1:25, 1:10, and 1:5) and three sand/gravel property combinations were considered. The slopes and material property combinations were selected to represent a range in barrier effectiveness. The porous media flow code used for this analysis was VAM3DCG, a three-dimensional, finite-element code which was able to use nonorthogonal grid discretizations and employed robust, efficient numerical techniques. Three-dimensional modeling demonstrated that flow in the hypothetical design exhibited cross-slope flow because of the pressure gradient produced in the third, cross-slope dimension. Barrier effectiveness was shown to be highly sensitive to the sand/ gravel material properties. Barrier slope was less important, especially for the effective material combinations. The presence of three-dimensional flow could be important in a performance assessment if the quantity of water predicted to breach the capillary barrier by a two-dimensional model were different from that predicted by a three-dimensional model. Comparative modeling demonstrated that a two-dimensional analysis resulted in underestimation of barrier effectiveness. For the considered design, two-dimensional modeling is a conservative, yet reasonable, approach in a performance assessment application.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1745-6584.1996.tb02053.x
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