Development of the CHEMTARD Coupled Process Simulator for Use in Radiological Assessment

摘要

This report describes features of CHEMTARD (Chemical Transport Adsorption Redox and Decay); a directly-coupled chemical transport code, developed to aid the DOE in carrying out post-closure radiological risk assessments. The program is based on the Lawrence Berkeley code, CHEMTRN, and simulates the one-dimensional transport of aqueous chemical species by advection and/or diffusion while accounting for phase transfer by reversible precipitation-dissolution, ion-exchange or surface adsorption. New models for radioactive decay, oxidation-reduction reactions, flexible boundary conditions and multi-layered transport have significantly enhanced the ability of the code to perform coupled process calculations. Although originally developed for studies involving shallow land disposal of low level wastes, the models contained in CHEMTARD are sufficiently general to allow thermodynamic treatment of chemical transport for porous flow through all saturated aquifer systems. (ERA citation 13:039349)