NESC9811 SWENT.

1. NAME OR DESIGNATION OF PROGRAM:  SWENT.

3. DESCRIPTION OF PROGRAM OR FUNCTION

SWENT (Simulator for Water, Energy, and Nuclide Transport) simulates the transient transport of  fluid, heat, an inert component, and any number of radionuclides through a heterogeneous geologic medium either in three dimensional  or radial geometries. The first three transport processes are coupled by the fluid properties of density and viscosity. The velocity field is derived from the solution of the coupled processes and used in the fourth process. Since radionuclides are present in trace quantities only, this process is not coupled to the first three. Aquifer porosity is treated as a function of pressure.

4. METHOD OF SOLUTION

The resulting system of nonlinear partial differential equations is solved by finite-difference approximations, suitable linearization schemes, and an iterative technique to reduce the errors that arise in linearization.

5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

In the current release, the simulations are limited to maxima of 20 wells, 7 overburden vertical layers, 7 underburden vertical layers, 50 entries in the aquifer influence function tables, and 10 entries in  each of the viscosity versus temperature and concentration tables.

6. TYPICAL RUNNING TIME:

NEA-DB ran the test cases included in this package on a CDC CYBER 830 computer. Execution time varied for the different cases from 5 seconds to 10 minutes.

7. UNUSUAL FEATURES OF THE PROGRAM

Options are available which permit simulation of any one of the individual processes or coupled combinations of the processes. A special option is available to treat steady-state fluid flow with transient radionuclide transport. SWENT offers a wide choice in the specification of boundary conditions.
To provide control of numerical diffusion and overshoot or undershoot, the model permits the choice of backward or central difference approximations in the time-integration scheme and in the  convective terms of the transport processes. Either direct or iterative techniques may be selected for the solution of matrix equations, as appropriate, from considerations of storage and time requirements.
The three-dimensional simulation capability of the model can be adapted to a simulation of the fractured medium in one and two dimensions. The capability to link SWENT to PABLM (NESC Abstract 926), a dose-to-man code, is incorporated.
The program can be used in a wide variety of ground-water applications. When operated sequentially with PABLM it can be used to address the complete assessment of the site subsystem, and since  it models coupled processes, it is suitable for various repository assessments.

8. RELATED AND AUXILIARY PROGRAMS:

10. REFERENCES:

- INTERA Environnemental Consultants, Inc. :
  SWENT: A Three-Dimensional Finite-Difference Code for the
  Simulation of Fluid, Energy, and Solute Radionuclide Transport
  ONWI-457 (April 1983)

11. MACHINE REQUIREMENTS:  70K words.

2,722,000 (octal) words on CDC CYBER 830 (with fixed core memory allocation).

13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED:  SCOPE and NOS.

NOS2.5.1 (CDC CYER 830).

14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS:

15. NAME AND ESTABLISHMENT OF AUTHORS

          M.J. Golis
          Office of Nuclear Waste Isolation
          Battelle Project Management Division

File name	File description	Records
NESC9811_01.001	Information file	86
NESC9811_01.002	JCL and control information	46
NESC9811_01.003	SWENT FORTRAN source	14678
NESC9811_01.004	Nuclide data library	284
NESC9811_01.005	CONVRT FORTRAN source	20
NESC9811_01.006	Sample problem 1	132
NESC9811_01.007	Sample problem 2	198
NESC9811_01.008	Verfication test 1, Cartesian case	97
NESC9811_01.009	Verfication test 1, radial case	97
NESC9811_01.010	Verfication test 2, Cartesian case	114
NESC9811_01.011	Verfication test 2, radial case	111
NESC9811_01.012	Verfication test 3	50
NESC9811_01.013	Verfication test 4	55
NESC9811_01.014	Verfication test 5	52
NESC9811_01.015	Verfication test 6	62
NESC9811_01.016	Verfication test 8	88
NESC9811_01.017	Verfication test 9	71
NESC9811_01.018	Sample problem 1 output	2772
NESC9811_01.019	Sample problem 2 output	2680
NESC9811_01.020	Verification test 1 output	1282
NESC9811_01.021	Verification test 1 output, radial case	948
NESC9811_01.022	Verification test 2 output, Cartesian case	1385
NESC9811_01.023	Verification test 2 output, radial case	1049
NESC9811_01.024	Verification test 3	692
NESC9811_01.025	Verification test 4	665
NESC9811_01.026	Verification test 5	1406
NESC9811_01.027	Verification test 6	1379
NESC9811_01.028	Verification test 8	8280
NESC9811_01.029	Verification test 9	1133