Abstract
For the safety assessment of geologic disposal of high-level radioactive wastes, an analy-tical solution was obtained for one-dimensional migration of radionuclide through two-layered geologic media without dispersion. By applying it to geologic media composed of granite and soil layers, the effect of interlayer boundary on the discharge profile of radionuclides in decay chains into biological environment is examined.
The time-space profiles of radionuclides in the vicinity of interlayer boundary are much complicated as shown in the results of calculation. Those profiles in case that the ground-water flows through granite followed by soil are quite different from those in case that the groundwater flows through soil followed by granite. Each of complicated dependence of profiles on time and space can be physically explained. The characteristic profiles in the vicinity of interlayer boundary have not been discussed previously.
Recently, numerical computer codes has been developed to apply to much more realistic geologic situations. However, the numerical accuracies of the codes are necessary to be confirmed. This is achieved by comparing computational results with results from analytical solutions. The analytical solution presented will serve as a bench-mark for numerical accuracy.
