Relationship among Performance of Geologic Repositories, Canister-Array Configuration, and Radionuclide Mass in Waste

Abstract

The relationship among the repository performance, the canister-array configuration, and the radionuclide mass in waste has been investigated by developing a radionuclide-transport model, where multiple waste canisters and their spatial configuration are taken into account.

A mathematical analysis and numerical results show that the radionuclide concentration in the groundwater leaving the canister array increases with the number of canisters included in a water stream parallel to the array axis, but not necessarily in a linear manner. The dependency on the number of canisters is determined mainly by canister-array configuration to the water flow and by model assumptions for transport between multiple canisters.

Reduction in the initial mass loading in the waste can potentially have significant effects on the repository performance. The way the mass-reduction effects on the repository performance appear is related to the canister-array configuration. Thus, designs for a repository and a partitioning-transmutation system should be done in a coupled manner.