Method of deep borehole disposal of nuclear waste

摘要

A method of deep borehole disposal of nuclear waste comprises ```the steps of: encasing the waste as a solid cylinder (30); ```arranging that the cylinder heats by nuclear reactions in the cylinder to a minimum temperature (preferably about 200 {C under the conditions of disposal in a deep borehole, but less than a critical temperature (about 1000 {C) at which the integrity of the cylinder is compromised; ```providing a deep borehole (10) (preferably 3-5 km), lining same with a liner (14) (preferably a perforated liner) and deploying at least one of cylinders in said borehole; and ```after deployment, releasing flowable solid metal beads above said cylinders so that the space (20,22) around the cylinder and between the cylinder and borehole is filled with said beads, wherein, ```the density of said metal is less than the density of the cylinder by no more than 50%; ```the melting temperature of said metal is less than said minimum temperature; and sufficient of the beads are released so that, when they melt and displace flowable material of lesser density than said metal in the space around the cylinder, at least three-quarters of the height of the cylinder is encased in said metal. For preference, the metal beads are an alloy of lead and tin and/or bismuth.