ABSTRACT
Interactions between contaminants and clay buffers and barriers used in high-level radioactive waste (HLW) and hazardous solid waste (HSW) containment occur when (a) leachates from waste landfills escape from their confining geomembrane liner system, thereby allowing the leachates to make direct contact with the underlying engineered clay barrier/liner system and substrata, and (b) corrosion products and fugitive radionuclides escaping from an encapsulated HLW canister come into direct contact with the surrounding engineered clay buffer system. Interactions between contaminants and clays also occur when (a) natural subsurface clay strata that are being used as contaminant-attenuating material react with incoming leachates and (b) clays that are used in specially designed permeable reactive barriers (PRBs) intercept leachates as their planned design function. In such instances, one relies on the assimilative capability of the clay. In the case of PRBs, clays and other attenuating aids are used to control, mitigate and even eliminate the transport of contaminants. These will be discussed in a later section in this chapter.
