Recent Advances in Repository Seal Materials

Abstract

One long-term solution proposed for isolating radioactive waste from the biosphere is containment in underground geologic repositories. A requirement for this procedure is that most penetrations into the repository region be sealed following emplacement of the waste. The general requirements of repository seal materials and the seal system are that these potential pathways to the biosphere be sealed adequately to prevent a) excess fluid flow into the repository and b) radionuclides in the waste from reaching the biosphere in quantities in excess of acceptable levels. For boreholes, shafts and tunnels it is generally recommended that in the post-closure phase, the permeability of sealed boreholes and shafts be approximately the same as the host rock or the aquitards in the zones where aquitards are intersected.