The considerations involved in the evaluation of the suitability of any geological formations for the disposal of radioactive wastes are illustrated by summarizing some of the studies performed in the southeastern New Mexico region on the bedded salt concept. These investigations fall into three main categories:1. Evaluation of the natural integrity of the formation. In addition to standard geological and hydrological studies, special investigations of the subsurface dissolutioning of the salt formation, the seismic stability of the region, and the possibility of previous mass flowage of the salt have been completed. These results will be confirmed by core drilling and testing currently in progress.2. Evaluation of the effects of the operation of a waste disposal facility on the geological characteristics of the area over the short term. These studies include prediction of the thermal transient resulting from the radioactive decay heat deposited in the rocks and its effects, such as the migration of brine inclusions up the thermal gradients and the dehydration of moisture-bearing minerals. Other studies in this category are concerned with the possibility and consequences of radiation-induced energy storage in the salt and prediction of the deformations to be expected around the openings excavated in the salt formations.3. Evaluation of the effects which the operation of a repository and other activities of man may have on the integrity of the geological containment over the long periods that the waste remains hazardous. The principal analyses in this category involve the long-term deformations of the rocks overlying the repository area (including the slow development of a subsidence basin at the ground surface) and the prevention of adverse conditions resulting from penetrations of the salt by exploratory drilling for oil and gas accumulations.
