Effects of transport model alternatives incorporating precipitation on the performance of engineered barriers

The migration of radionuclide through bentonite was analysed by alternative models considering the precipitation caused by decay-chain ingrowth. In the realistic model, the temporal and spacial isotopic ratio in bentonite was taken into account for determining the shared solubility for each radionuclide. The release rate of radionuclide from the outer surface of bentonite to surrounding rock is generally lower iii such realistic analysis considering precipitation in bentonite than calculated by the model neglecting precipitation. This result shows the model not considering such effects is mostly conservative for the safety assessment.