Benchmark profiles for advection-dispersion migration of radionuclides through two-layered geologic media

Concentration profiles are presented for one-dimensional migration of radionuclides through two-layered geologic media. Complicated changes in concentration profiles of radionuclides around the interlayer boundary of the two layers can be demonstrated. These profiles are calculated by a computer code MIDIDOME (Migration with Dispersion through Doubly-layered Media), which is developed from semi-analytical solutions for migration of radionuclides in four (or less) member-decay chains. The Preferential-release model is applied, in which each element can have a different and time-dependent release rate from the waste form. The profiles can be used as benchmarks to check the accuracy of numerical analysis codes for radionuclide migration through geologic media. The effect of dispersion on migration through two-layered media is also discussed briefly. (author)