Validation of glass dissolution and Si diffusion parameters with a combined glass dissolution-diffusion experiment in Boom Clay

    Research outputpeer-review


    Knowledge on glass dissolution and silica diffusion in Boom Clay is validated by experiments where both phenomena could be studied simultaneously. SON68 glass coupons, doped with radioactive 32Si, were sandwiched between two cores of humid Boom Clay and heated to 30°C. At the end of the experiment, the mass loss of the glass coupon was measured, and the clay core was sliced to determine the diffusion profile of the 32Si dissolved from the glass. These data were completed with analyses of the clay water and surface analyses for analogous tests with undoped glass. The results are interpreted by assuming congruent glass dissolution at a constant rate, with a glass silica saturation concentration between 14 and 20 mg/l, a forward glass dissolution rate (at zero silica concentration) of 0.028 g.m-2day-1, an apparent silica diffusion coefficient in the clay of 1.4 10-12 m2sec-1, and a distribution coefficient for silica on Boom Clay between 0.010 and 0.075 m³kg-1. These parameter values are close to the range found in literature. The modeling exercise shows that the existing knowledge about the subsystems glass and clay can succesfully be integrated to describe the coupled processes in the whole system.
    Original languageEnglish
    Title of host publicationSymposium Proceedings. Scientific Basis for Nuclear Waste Management XXIX
    Place of PublicationWarrendale, United States
    StatePublished - Jun 2006
    Event2005 - MRS : 29th International Symposium on the Scientific Basis for Nuclear Waste Management - Gent
    Duration: 12 Sep 200516 Sep 2005


    Conference2005 - MRS
    Abbreviated titleMRS2005

    Cite this