Fast method for simulation of radionuclide chain migration in dual porosity fracture rocks
2006 (English)In: Journal of Contaminant Hydrology, ISSN 0169-7722, E-ISSN 1873-6009, Vol. 88, no 04-mar, 269-288 p.Article in journal (Refereed) Published
In fractured rocks with a porous rock matrix such as granites, radionuclides will flow with the water in the fracture network. The nuclides will diffuse in and out the rock matrix where they can sorb and be considerably retarded compared to the water velocity. A water parcel entering the network will mix and split at the fracture intersections and parts of the original parcel will traverse a multitude of different fractures. The flowrates, velocities, sizes and apertures of the fractures can vary widely. Normally one must solve the transport equations for every fracture and use the effluent concentration as inlet condition to the next fracture and so on. It is shown that under some weakly simplified conditions it suffices to determine one single parameter group containing information on the flow wetted surface that a water parcel contacts along the entire path. It is also shown how this can be obtained. Then, solving the transport equations only once for time and location along the path gives the concentration and nuclide flux of every nuclide in the chain everywhere along a path. The same solution actually is valid for every path in the network. This dramatically reduces the computation effort. The same approach can be used for models based on streamtubes.
Place, publisher, year, edition, pages
2006. Vol. 88, no 04-mar, 269-288 p.
radionuclide chain decay, fracture networks, radionuclide migration, matrix diffusion, Flow Wetted Surface, dual porosity, negligible matrix permeability, solute transport, single fracture, porous-media, contaminant transport, tracer experiments, fissured rocks, decay chain, flow, diffusion
IdentifiersURN: urn:nbn:se:kth:diva-16239DOI: 10.1016/j.jconhyd.2006.07.003ISI: 000243181000007ScopusID: 2-s2.0-33751309845OAI: oai:DiVA.org:kth-16239DiVA: diva2:334281
QC 201005252010-08-052010-08-05Bibliographically approved