Studies of the geologic stability of the Canadian shield for siting a nuclear fuel waste disposal facility

AECL Research has undertaken a variety of studies to address issues related to understanding and assessing the geologic stability of plutonic rocks of the Canadian Shield to assist in siting a nuclear fuel waste disposal facility. These studies include: monitoring the current levels of seismicity of the Shield and using this information to bound the probability of the site specific occurrence of an earthquake large enough to affect the integrity of the geosphere surrounding a disposal vault; and, examinations of the age, origin and evolutionary history of fractures found in plutonic rocks of the Shield. A case study is presented for a well-characterized fracture at the side of AECL's Underground Research Laboratory (URL) to illustrate an approach for examining the history of fracture reactivation and propagation at a specific site. (authors). 19 refs., 4 figs., 1 tab