Lawrence Berkeley National Laboratory

Argentina is faced with the challenging problem of developing technology for near-surface disposal and isolation of low- and intermediate-level radioactive waste (LILW). The preferred option for disposal of LILW (including both relatively short-lived and long-lived radionuclides) is to use disposal facilities that are near-surface--either above or below ground level [IAEA, 1985; 2001a; 2004]. How individual components of a waste disposal system perform (including waste forms, waste containers, engineered barriers and host environment) will determine system safety and the safety of the surrounding environment [IAEA, 1999]. The lack of appropriate engineering for the backfill, and for the selection of sealing and covering materials for trenches, vaults, and ditches, could result in the escape of radionuclides from the disposed wastes [IAEA, 1994a; 2001b]. Therefore, assessment and design of backfill, barriers, and cover materials are very important, both for preventing invasion of water into the disposal system, and for retarding radionuclides that could potentially migrate from the system into the atmosphere or groundwater [IAEA, 1982; 1994b; 2001a].