State-of-the-Art Evaluation of Repository Sealing Materials and Techniques.

Abstract

AbstractUnder the auspices of the OECD/NEA Stripa Project, a state-of-the-art evaluation of repository sealing materials and techniques has been undertaken with particular application to crystalline rock. The objectives of the evaluation were (1) to review progress to date in the development of repository sealing materials and emplacement techniques; (2) to identify priority materials for sealing narrow aperture fractures in crystalline rock, including issues of technical concern to the long-term effectiveness of such materials; and (3) to provide a framework for advancing an in situ fracture-sealing test program that can be designed and implemented at the Stripa Mine.The classes of sealing materials that were considered included cementitious materials, natural clay materials, chemical grouts, fracture-filling synthetic minerals, ceramics, and metals. Of these, cementitious materials and natural clay materials were recommended as high-priority materials for further study because they can be designed to meet desired repository performance characteristics, there is considerable history of successful use in similar engineering applications, and there is indirect evidence that they will continue to perform as expected for long periods of time. Techniques for the emplacement of these sealing materials in rock fractures include pressure injection, dynamic (or vibratory) injection, and electrophoresis.