A system and method for storing high level waste. In one aspect, the invention is a system comprising: an inner shell forming a cavity for receiving high level waste, the cavity having a top and a bottom; an outer shell surrounding the inner shell so as to form a space between the inner shell and the outer shell; at least one opening in the inner shell at or near the bottom of the cavity, the at least one opening forming a passageway from the space into the cavity; a lid positioned atop the inner and outer shells, the lid having at least one inlet vent forming a passageway from an ambient atmosphere to the space and at least one outlet vent forming a passageway from the cavity to the ambient atmosphere. In another aspect, the invention is a method of using the system to store high level waste. In yet another aspect, the invention does not require the aforementioned lid but further comprises a floor plate wherein the inner and outer shells rest atop and are connected to the floor plate.