Sensitivity analysis on impact of continental glaciation on radionuclide transport

This paper describes the sensitivity study of the impact of continental glaciation on radionuclide transport from a generic repository sited in granitic rock. Monte Carlo simulations with a combined near- and far-field transport models are performed, and the model input parameter sensitivities are evaluated. The dose rates for a subset of radionuclides that could be potentially important to repository performance are calculated. The analyses are conducted for an undisturbed radionuclide release scenario. The analyses show that radionuclide transport is significantly influenced by the future glacial cycle. The total dose rates are influenced mostly by the groundwater flow rate change during the glacial flushing period. Changes in sorption coefficients during glacial flushing periods only influence the redox-sensitive species, which are not the major contributors to the total dose rates in this generic example. Potential engineered barrier failure due to repeated exposure of bentonite buffer material to dilute glacial melt water also affects the total dose rates with its influence magnitude determined by the fraction of waste packages affected and the time when buffer material is lost.