ANOMALOUS DIFFUSION IN REGULAR FRACTURED MEDIA (PREPRINT IBRAE-2002-03)

Preprint IBRAE-2002-03

Dykhne A.M., Dranikov I.L., Kondratenko P.S., Popov A.V.

Contaminant transport in regular heterogeneous media consisting of narrow areas (“fractures”) with diffusivity D and a matrix with the diffusivity d (D being much greater than d) has been analyzed. Considered are the following models: single flat and single cylindrical fracture, systems of two and of an infinite number of parallel fractures, and an “interconnection” of two semi-infinite flat parallel fractures, coming close to each other. For single fractures it has been found the time range where the contaminant transport is of subdiffusion behaviour When the ratio D/d  is extremely large, the regime of anomalous diffusion (subdiffusion) becomes to be asymptotic. Therefore, in connection with contaminant transport in fractured rocks, we may deal with the effect of suppression of the dispersion in fractures. Fracture “interconnections” are found to be inessential for complex systems diffusion time-patterns. The results obtained may be helpful for the development of methods to assess reliability of radioactive waste storage in rock massifs.

Bibliographical reference 

Dykhne A.M., Dranikov I.L., Kondratenko P.S., Popov A.V. ANOMALOUS DIFFUSION IN REGULAR FRACTURED MEDIA. Preprint IBRAE-2002-03. Moscow: Nuclear Safety Insitute RAS, February 2002, 15 p. — Refs.: 3 items.