Verification and validation of models : Far-field modelling of radionuclide migration
The aim of this project was to improve the capability, efficiency and realism of the NAMMU and NAPSAC codes, which simulate groundwater flow and solute transport. Using NAMMU, various solution methods for non-linear problems were investigated. The Broyden method gave a useful reduction in computing time and appeared robust. The relative saving obtained with this method increased with the problem size. This was also the case when parameter stepping was used. The existing empirical sorption models in NAMMU were generalised and a ternary heterogeneous ion exchange model was added. These modifications were tested and gave excellent results. The desirability of coupling NAMMU to an existing geochemical speciation code was assessed. Numerical methods for the solution of cases involving sharp fronts in solute concentration were studied, and also models of solute dispersion. A very efficient particle-following algorithm has been added to the NAPSAC code, enabling tracer transport to be predicted through large fracture networks.
Bibliographic Reference: EUR 14114 EN (1992) 125 pp., FS, ECU 13.50
ISBN: ISBN 92-826-3860-X
Record Number: 199210580 / Last updated on: 1994-12-02
Original language: en
Available languages: en