The Boom Clay geochemistry: Natural evidence

    Research outputpeer-review

    Abstract

    In Belgium, the Boom Clay is studied as the reference formation for geological disposal of high-level radioactive waste and spent fuel. As the Boom Clay is considered as the main barrier for radionuclide migration/retention, a thorough characterisation of the clay and its pore water was done. This facilitates better understanding of the long-term geological processes and the distribution of the trace elements and radionuclides. From a mineralogical/geochemical point of view, the Boom Clay is considered as a rather homogeneous sediment, vertically as well as laterally. It is composed of detrital minerals, organic matter and fossils. Minerals are mainly clay minerals, quartz and feldspars. Minor amounts of pyrite and carbonates are also present. Small variations in mineralogical/geochemical composition are related to granulometrical variations. The radiochemical study indicates that the Boom Clay is in a state of secular radioactive equilibrium, meaning that the Boom Clay has not been disturbed for a very long time. Pore water sampling is done in situ from various piezometers, or by the squeezing or leaching of clay cores in the laboratory. These three pore water sampling techniques have been compared and evaluated. Boom Clay pore water is a NaHCO3 solution of 15 mM, containing 115 mg-1-1 of dissolved natural organic carbon. Some slight variations in pore water composition have been observed and can be explained by principles of chemical equilibrium.

    Original languageEnglish
    Title of host publication29th International Symposium on the Scientific Basis for Nuclear Waste Management XXIX
    Place of PublicationWarrendale, United States
    PublisherMaterials Research Society
    Pages1033-1040
    Number of pages8
    Volume932
    ISBN (Print)1558998896, 9781558998896
    DOIs
    StatePublished - 2006
    Event2005 - MRS : 29th International Symposium on the Scientific Basis for Nuclear Waste Management - Gent
    Duration: 12 Sep 200516 Sep 2005

    Publication series

    NameMaterials Research Society Symposium Proceedings
    Volume932
    ISSN (Print)0272-9172

    Conference

    Conference2005 - MRS
    Abbreviated titleMRS2005
    Country/TerritoryBelgium
    CityGent
    Period2005-09-122005-09-16

    ASJC Scopus subject areas

    • General Materials Science
    • Condensed Matter Physics
    • Mechanics of Materials
    • Mechanical Engineering

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