Thermodynamic study of potential non-dominant transfer processes of radionuclides in the geosphere
Most of the numerous physical and chemical phenomena inducing mass transfer in the geosphere, referred to as the "non-dominant transport processes", are usually neglected in calculations. In the peculiar conditions of radionuclide waste disposal some of these may be significant. It is therefore important to investigate those effects and take them into account for further safety studies. Attention is first focussed on the mathematical formalism describing the relationships between the physical and chemical gradients and the induced mass fluxes, based on irreversible thermodynamics. This allows the determination of orders of magnitude concerning three main "effects" : the Soret effect, the thermogravitational effect and the sedimentation effect. The temperature-induced phenomena seem to have more importance than others, due to the thermal field settling close to the buried waste. A rough analysis highlights their relatively high magnitude, especially in porous media. Numerical modelling is mainly based on the METIS code. The third section is devoted to the phenomena involving the electromagnetic field (telluric field, electro-kinetic, thermoelectric and electrochemical effects). The few numerical calculations performed show that at most these phenomena only represent a corrective factor to the main mass flux.
Bibliographic Reference: EUR 12672 FR (1990) 157 pp., FS, ECU 13.75
ISBN: ISBN 92-826-1291-0
Record Number: 199010782 / Last updated on: 1994-12-01
Original language: fr
Available languages: fr