[en] The present paper gives a general overview of mass transport in low permeability rocks under the coupled thermomechanical and hydrochemical effects associated with a nuclear waste repository. A classification of coupled processes is given. Then an ess is presented. example of a coupled process is presented. Discussions of coupled processes based on a recent LBL Panel meeting are summarized. 5 references, 3 figures, 4 tables

[en] The emplacement of a nuclear waste repository in a fractured porous medium provides a heat source of large dimensions over an extended period of time. It also creates a large cavity in the rock mass, changing significantly the stress field. Such major changes induce various coupled thermohydraulic, hydromechanic and hydrochemical transport processes in the environment around a nuclear waste repository. The present paper gives, first, a general overview of the coupled processes involving thermal, mechanical, hydrological and chemical effects. Then investigations of a number of specific coupled processes are described in the context of fluid flow and transport in a single fracture, two intersecting fractures and a fractured porous medium near a nuclear waste repository. The results are presented and discussed

No abstract available

[en] The present paper presents considerations on studies that would be required for preclosure monitoring and performance confirmation of a nuclear waste geologic repository in an unsaturated zone. The critical parameters that should be monitored are reviewed and two scales of measurement relevant to monitoring activities, room scale and repository scale, are taken as a framework for investigation. A number of monitoring methods based on geophysics, geohydrology, and geochemistry are briefly summarized for their potential usefulness for preclosure monitoring and performance confirmation of the geologic repository. Particular emphasis is given to measurement of the spatial distribution of parameters in contrast to single-point measurements of quantities. 12 refs., 1 fig., 1 tab

[en] Studies of far-field phenomena affecting repository performance have focussed on the role of fractures and other heterogeneities in the potential transport of radioactive solutes from the repository to the biosphere. The present paper summarizes two recent advances in the subject: the channeling model for the understanding and analysis tracer transport in variable-aperture fractures and the modeling of coupled thermo-hydro-mechanical processes in geologic formation around a repository. The paper concludes with remarks on the need for duality in the approach to performance assessment. One line of the duality is fundamental studies and the other, goal-oriented assessment to satisfy regulatory requirements. 15 refs., 10 figs., 1 tab

No abstract available

[en] The safety assessment of a nuclear waste repository requires the use of models. Such models need to be validated to ensure, as much as possible, that they are a good representation of the actual processes occurring in the real system. In this paper we attempt to take a broad view by reviewing step by step the modeling process and bringing out the need to validating every step of this process. This model validation includes not only comparison of modeling results with data from selected experiments, but also evaluation of procedures for the construction of conceptual models and calculational models as well as methodologies for studying data and parameter correlation. The need for advancing basic scientific knowledge in related fields, for multiple assessment groups, and for presenting our modeling efforts in open literature to public scrutiny is also emphasized. 16 refs

[en] Contributed papers were in the following subject areas: geochemistry, geohydrology, and geomechanics. In addition to the contributed papers, current field projects were reviewed. Individual papers were processed separately. (LM)

[en] This book deals with coupled processes which affect a nuclear waste repository. While there are many descriptive accounts of environmental degradation resulting from various land uses, the author emphasizes the geomorphic processes responsible for such changes and the reasons why various reclamation practices are valuable in environmental management

[en] The Geoscience Technical Support activities in the Geologic Repository Project (GRP) at LBL covered a range of reports and reviews in FY89, particularly reviews of Study Plans of the Yucca Mountain site and their associated Comment Resolution Workshops. LBL sought to be responsive and active in meeting DOE's need for geoscience technical support for nuclear waste repositories. In addition, in consultation with DOE/HQ, the authors investigated and presented DOE with well-considered scientific inputs to program directions and new areas of needed work. This included the development of a white paper and proposed work plan on preclosure monitoring and performance confirmation that grew out of a request made by DOE to LBL to consider such studies for a repository in the unsaturated zone. This year also saw the beginning of a quality assurance program for GRP