Near-field concepts for disposal of radioactive waste in a clay formation: Final report

Didier De Bruyn, F. Fonteyne, Jan Marivoet, Marcel Monsecour, Luc Noynaert, Martin Put, Geert Volckaert

    Research outputpeer-review


    The aim of this study is to develop backfilling concepts with capabilities to attenuate near-field effects of mined repositories in argillaceous host rocks by examining the characteristics and the performance of a clay host rock and potentially favourable engineered barriers and assessing system components which contribute to their durability. The main topics are : - study of near field clay and materials used in HLW underground repository; - study of selected representative emplacement configurations of HLW-repository; - proposal of a concept and recommendations for future works. The main results are : - the HLW canister, used as reference, cannot be considered as a preventive barrier due to its collapse at an outside pressure of 2.5 MPa and to the sensitivity of austenitic steel at the stress-corrosion cracking; - sulfate resistant concrete (SRPC or C3A = 0 %) can be used as backfilling material or as lining if it is sufficiently matured before being solicited by the thermal loading generated by the HLW packages; - excavated Boom clay can be used as buffer material but future research is necessary to determine the appropriate processing to be used and the eventual adjuvant(s) to be considered; - a program called "TEMPRES" is now available to compute temperature, pore-water pressure and stresses around heating sources in clay host rock, its validation is not yet fully performed but the first results obtained by modelling the BACCHUS test are promising; - a program called "SOURCE" was developed to approximate the pore water pressure response at digging and drilling works performed in a isotropic medium where the pore fluid flow can be related to the pore water pressure by the Darcy's law. The proposed concept is a first attempt to attenuate the near-field effects of HLW in argillaceous rocks by using engineered barriers taking into account their properties but also possible placement procedures.
    Original languageEnglish
    PublisherPublications Office of the European Union
    Number of pages132
    ISBN (Print)92-826-3360-8
    StatePublished - 1992

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