An aboveground vault (AGV) is a concrete, metal, or masonry structure built above ground level (Fig. 5). A vault may be a simple reinforced concrete box with a poured concrete roof, or it may be a more elaborate
structure resembling a large warehouse. The principal advantage of an AGV is that it allows easy recovery of wastes for further processing or reuse. Its principal disadvantage is that the structure is not protected by earth from the effects of weather, intrusions, or accidents. Consequently, an AGV is often considered more for temporary storage than for permanent disposal. AGVs have been used at the West Valley Demonstration Project in New York and at the Point Lepreu and Bruce sites in Canada.
5.5 Earth-Mounded Concrete Bunker
An earth-mounded concrete bunker (EMCB) is a structure built partly below ground and partly above ground (Fig. 6). Wastes are segregated according to activity; higher activity (class B/C) wastes are embedded in concrete vaults or ‘‘monoliths’’ below ground level, and lower activity (class A) wastes are then placed atop the vaults. The wastes are covered with an impermeable layer of clay and a layer of topsoil to form a mound or tumulus. This method is used in France at the Centre de La Manche and the Centre de l’Aube as well as in Canada at the Whiteshell Nuclear Research Establishment.