Suitability of unconsolidated sediments for hosting low-level radioactive waste disposal facilities

Abstract

Among the unconsolidated sediments, sand deposits are considered a rather unconventional geologic host medium for siting radioactive waste repositories, the clays being the preferred choice. A closer examination of the various geologic media, however, shows that in each case there are advantages and disadvantages. The key to safe and cost-effective disposal is to match the engineered design of the facility to the site's characteristics as well as the nature of the waste to be disposed of. In humid climates, free-draining sediments such as sand can provide the advantage of eliminating concern related to the “bathtub effect.”At Chalk River Nuclear Laboratories (CRNL), a sand dune has been proposed for hosting a low-level radioactive waste disposal facility. This paper discusses the suitability of unconsolidated sediments for radioactive waste disposal in general; in particular, it provides the rationalization for the selection of a sand dune as the host site at CRNL. Key words: radioactive waste, disposal facilities, unconsolidated sediments, site suitability, trench cover materials, sreismicity, soil liquefaction.