1. NAME AND TITLE

RANCHMD: Radionuclide Chain Transport With Matrix Diffusion.

2. CONTRIBUTORS

Paul Scherrer Institute, Würenlingen, Switzerland through the NEA Data Bank, Gif-sur-Yvette, CEDEX, France.

3. CODING LANGUAGE AND COMPUTER

FORTRAN 77; VAX computers.

4. NATURE OF PROBLEM SOLVED

RANCHMD is used in calculating two-dimensional radionuclide chain transport in water conducting zones, represented by a network of either planar fractures or tubelike veins.

5. METHOD OF SOLUTION

RANCHMD has been developed for the numerical solution of coupled parabolic type partial differential transport equations. It takes into account general initial and mixed boundary conditions. The transport equation is solved in semidiscretized form with variable order for the space derivatives. The integration of the differential equations is handled by a modified version of the IMSL subroutine DGEAR. The choice of time step size is done automatically and controlled by the requested accuracy.

6. RESTRICTIONS OR LIMITATIONS

The code can handle a maximum of 4 nuclides and 10 layers.

7. TYPICAL RUNNING TIME

On the VAX 8810, the following CPU times were noted: BOE1093 -- 36s; GV1A -- 3m,16s; GV3A1 -- 1m,50s; SEDI_3_18 -- 2m,12s.

8. COMPUTER HARDWARE REQUIREMENTS

The code runs on the VAX family of computers.

9. COMPUTER SOFTWARE REQUIREMENTS

The VAX FORTRAN compiler is used under the VMS operating system.

10. REFERENCES

``RANCHMD--Radio Nuclide Chain Transport With Matrix Diffusion,'' Paul Scherrer Institute, Switzerland (February 1990).

J. Hadermann, F. Roesel, Radionuclide Chain Transport in Inhomogeneous Crystalline Rocks: Limited Matrix Diffusion Effective Surface Sorption, Technical Report 85-40, Swiss Federal Institute, Würenlingen, Switzerland (February 1985).

R. W. Hartley, Release Of Radionuclides to the Geosphere from a Repository for High- Level Waste, EIR-Bericht Nr. 554 (February 1985).

J. Hadermann and A. Jakob, Modelling Small Scale Infiltration Experiments Into Bore Cores of Crystalline Rock and Break-Through Curves, EIR-Bericht Nr. 622 (April 1987).

11. CONTENTS OF CODE PACKAGE

Included are the referenced documents and 1 DS/HD 5.25-inch diskettes (1.2 MB).

12. DATE OF ABSTRACT

August 1991.