CRACKER - A PROGRAM COUPLING INHOMOGENEOUS CHEMISTRY AND TRANSPORT

CRACKER is a program coupling chemistry and transport. Ir simulates ch emical reactions of ground water Bowing through a plane fracture. Prop erties such as initial composition of the water, mineralogical composi tion of the rock, temperature gradients and flow velocity of the water serve as inputs for the modelling. The program is designed to handle inhomogeneous rock properties, like redox fronts, regions with differe nt mineralogy, etc. It is even able to handle the frequent situation o f a rock violating the phase rule. In the CRACKER model, a rock is rep resented by a random distribution of minerals across the surfaces of a fracture. Water moves along the fracture. Diffusion perpendicular to the Bow direction is modelled by a mixing process. No diffusion parall el to the flow direction is simulated in the present program version. The program is supplied with an interface that makes use of some 25 sc reens to guide the user through the procedure of setting up a simulati on. CRACKER is a package of several programs, most of them written in C. Chemical equilibrium calculations are mostly performed by the well- known geochemical program PHREEQE. The CRACKER program has been succes sfully used to simulate waters from the Aspo site at the Swedish east coast. (C) 1998 Elsevier Science Ltd. All rights reserved.