Anion scavengers for low-level radioactive waste repository backfills

Minimization of I-129(-) and (99) TcO4- transport to the biosphere is critical to the success of low level radioactive waste (LLRW) storage facilities. Here we experimentally identify and classify potential sorbent materials for inclusion in LLRW backfills. For low pH conditions (pH 4-5), Cu-sulfides and possibly imogolite-rich soils provide K-d's (distribution coefficients) of roughly 18 mL g(-1) for I-, and 10(2) mL g(-1) for TcO4-. At near neutral pH, hydrotalcites, Cu-oxides, Cu-sulfides, and lignite coal possess K-d's on the order of 10(2) mL g(-1) for both I- and TcO4-. At high pH (pH > 10), such as might occur in a cementitious LLRW facility, calcium monosulfate aluminate K-d's are calculated to be roughly 10(2) mL g(-1) for both both I- and TcO4-.