Can geologists ensure isolation of radioactive wastes in deep rock formations over thousands of years?

A number of host rocks are under consideration worldwide for deep geological disposal of radioactive wastes. The choice of host rock is driven by a number of considerations. Homogeneity of the rock unit, physico-chemical properties, hydraulic properties, the mineralogy and petrology of the rock unit, thermal and mechanical properties, and the anticipated response to waste emplacement are few technical aspects influencing the choice of host rocks.