Selection of radioactive waste disposal site considering natural processes

To dispose the radioactive waste, it is necessary to consider the transfer of material in natural environment. The points of consideration are 1) Long residence time of water 2) Independence of biosphere from the compartment containing the disposal site in the natural hydrologic cycle 3) Dilution with the natural inactive isotope or the same group of elements. Isotope dilution for 129I and 14C can be expected by proper selection of the site. 241Am and 239Pu will be homogenized into soil or sediment with insoluble elements such as iron and aluminium. For 237Np and 99Tc anionic condition is important for the selection. From the point of view of hydrologic cycle, anoxic dead water zone avoiding beneath mountain area is preferable for the disposal site. (author)