1. NAME AND TITLE

CHAINT-MC: A Two-Dimensional Model for the Analysis of Contaminant Transport in a Fractured Porous Medium

2. CONTRIBUTORS

Battelle Pacific Northwest Laboratories, Richland, Washington.

3. CODING LANGUAGE AND COMPUTER

FORTRAN 77; Cray XMP.

4. NATURE OF PROBLEM SOLVED

CHAINT-MC is a two-dimensional finite element model applicable to the transport of a dissolved radionuclide in a fractured porous medium along with radioactive chain decay and subsequent transport of the dissolved daughters.

5. METHOD OF SOLUTION

The conceptual modeling approach is based on representing the space domain by a vertical cross section. The mathematical model embodied by CHAINT is based on the physical law of conservation of mass. Physical processes accounted for in the model include advection, diffusion, dispersion, and retardation along with mass decay and production/injection.

6. RESTRICTIONS OR LIMITATIONS

In generating a two-dimensional finite element mesh, the following guidelines should be used: a) quadrilateral elements should be used for most of the mesh; b) element aspect ratios should not exceed roughly 100; c) midside nodes should be located in the middle third of the element side or length; d) the element numbering sequence should be continuous and should begin along the side of the grid with the fewest elements.

7. TYPICAL RUNNING TIME

The code was tested on a Cray XMP under the CTSS operating system. The sample problem took less than .4 second of CPU time.

8. COMPUTER HARDWARE REQUIREMENTS

The code will run on the Cray computers.

9. COMPUTER SOFTWARE REQUIREMENTS

The code is written in FORTRAN 77. On the Cray, the compiler used was CFT under the CTSS operating system.

10. REFEENCES

a. Included in the package:

Niall W. Kline and Robert G. Baca. CHAINT Computer Code: Users Guide, RHO-BW- CR-144 P, Rockwell International, Richland, Washington, December 1985.

b. Background information:

B. Sagar, P. Eslinger and R. G. Baca. ``Probabilistic Modeling of Radionuclide Release at the Waste Package Subsystem Boundary of a Repository in Basalt,'' Nuclear Technology, Vol. 75, pp. 338-347, December 1986.

11. CONTENTS OF CODE PACKAGE

Included are the referenced document and one DS/DD 5.25-inch diskette (360 K), containing the source code, sample input and output.

12. DATE OF ABSTRACT

March 1991.