Iodine retention and migration Behaviour in Boom Clay. Topical report. First full draft

This report presents the most up-to-date understanding of iodine chemistry and transport behaviour in the Boom Clay formation (status 2010). It discusses the experimental data obtained at SCK•CEN, and the concepts that have been developed to interpret these data. These data and concepts are evaluated against published data on iodine, with the focus on experiments performed in similar geochemical environments (especially the Callovo-Oxfordian and Opalinus formations). From this discussion, a phenomenological model is developed that is applicable to describe iodine transport under present-day conditions in Boom Clay at the Mol site. Moreover, also the parameter values needed in the model are extracted. These parameters are either a so-called “best estimate” (the most representative value for a given parameter best suited to describe iodine migration), an “expert range” (the range of values within which experts expect the parameter value to lie), or a “source range” (the range of values outside of which the parameter value is very unlikely to lie, considering current knowledge).