FEMWATER BLT, Water or Waste Transport in Soil

1 - Description of program or function: FEMWATER,BLT is used to model release and transport of contaminants from wastes stored in metallic containers in saturated or unsaturated soil systems including low- level waste disposal sites. Both programs provide two-dimensional, time-dependent, finite-element analyses. FEMWATER calculates water velocity, moisture content, and pressure head in unsaturated/ saturated porous media. BLT, a modification of the FEMWATER code, predicts container degradation, waste form leaching, and radionuclide migration in unsaturated porous media. 2 - Method of solution: FEMWATER and BLT perform two-dimensional time- dependent analyses using the finite element method. Nonlinearities in the unsaturated flow equations are handled through Picard iteration. The transport equations in BLT are linear, and Gaussian elimination is used to solve the matrix equations. 3 - Restrictions on the complexity of the problem - Maxima of: 528 finite elements (FEMWATER), 595 nodal points (FEMWATER), 225 finite elements (BLT), 252 nodal points (BLT), 100 waste-containing elements, 20 different waste types. These limits may be changed by re-dimensioning the appropriate arrays