The Geological Disposal of Spent Nuclear Fuel Beneath Sedimentary Basins

Abstract

The risk of contamination of the geosphere surrounding any relatively shallow (less than 1000 m) used nuclear fuel repository increases with time due to the eventual degradation of engineered materials used to contain the waste. The potential for the vertical movement of this contaminated material further in the geosphere, and possibly into the biosphere, will be largely dependent upon the vertical mobility of the contaminated groundwater in the fractures in the host-rock surrounding the repository. The primary emphasis for absolute containment, therefore, should be on the selection of a geological environment that provides great vertical separation from the biosphere accompanied with a hydrogeological environment that would, due to significant resident-fluid density stratification, contain water that is geologically ancient, having been inplace for millions of years. Rocks beneath some deep sedimentary basins could potentially provide this environment. In appropriate locations, repositories could be developed using drilling methods such as those currently used to develop oil and gas resources throughout the world.