Transport of gases in concrete barriers

A.W. Harris, A. Atkinson, Peter A. Claisse

    Research output: Contribution to journalArticle

    11 Citations (Scopus)
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    Abstract

    The performance of the cementitious materials within a radioactive waste repository as a physical barrier to the migration of radionuclides depends on the maintenance of the integrity of the barrier. One mechanism which can potentially compromise the behaviour of a repository is physical damage to the barrier caused by pressurisation as gas is generated. The maintenance of chemical homogeneity within the material used for backfilling the repository may also be compromised as a consequence of gas pressurisation through the formation of additional cracks and the reaction of cementitious materials with gases such as carbon dioxide. Consequently, the migration of gas within repository construction materials may be a significant parameter in both the design of a repository and the provision of a safety case for disposal. The migration of hydrogen, helium, methane, argon, and carbon dioxide have been studied for materials selected to be typical of repository structural concretes and grouts that are being considered for both repository backfilling and waste encapsulation and solidification. The apparent permeability of these materials to gas has been shown to be dependent on gas type and average pressure in the structural concrete due to the effects of Knudsen flow at pressures of the order of 100 kPa. This is not observed in the grouts due to the significantly greater pore size. The permeability coefficients for the grouts are several orders of magnitude greater than those of the concrete. Gas migration is strongly influenced by the degree of water saturation of the materials. The presence of interfaces within the materials results in an increase in permeability at higher degrees of water saturation. A simple model has been developed to simulate the effects of gas pressurisation. The tangential hoop stress at the surface of a void is calculated and comparison with the expected tensile strength of the materials is used to assess the potential for cracking. The backfill grouts seem to have sufficient permeability to disperse gas without crack formation.
    Original languageEnglish
    Pages (from-to)155-178
    JournalWaste Management
    Volume12
    Issue number2-3
    DOIs
    Publication statusPublished - 1992

    Fingerprint

    repository
    gas
    permeability
    crack
    carbon dioxide
    saturation
    encapsulation
    material
    backfill
    solidification
    argon
    tensile strength
    radioactive waste
    void
    helium
    homogeneity
    radionuclide
    methane
    hydrogen
    safety

    Keywords

    • concrete barriers
    • waste management

    Cite this

    Harris, A. W., Atkinson, A., & Claisse, P. A. (1992). Transport of gases in concrete barriers. Waste Management, 12(2-3), 155-178. https://doi.org/10.1016/0956-053X(92)90046-L

    Transport of gases in concrete barriers. / Harris, A.W.; Atkinson, A.; Claisse, Peter A.

    In: Waste Management, Vol. 12, No. 2-3, 1992, p. 155-178.

    Research output: Contribution to journalArticle

    Harris, AW, Atkinson, A & Claisse, PA 1992, 'Transport of gases in concrete barriers' Waste Management, vol. 12, no. 2-3, pp. 155-178. https://doi.org/10.1016/0956-053X(92)90046-L
    Harris, A.W. ; Atkinson, A. ; Claisse, Peter A. / Transport of gases in concrete barriers. In: Waste Management. 1992 ; Vol. 12, No. 2-3. pp. 155-178.
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