Patent ID: 8693609

Claim:
A method of forming a permanent depository in a borehole for highly radioactive material, the method comprising the steps of: forming in the borehole by metal fusion drilling a metal lining from a casting continuously formed from a metal melt and thereby forming the wall thickness of the metal lining of a lower borehole region such that the wall thickness increases from the top downward and a downward widening of the lower region; depositing the highly radioactive material for final storage in the lower region of the lined borehole; and melting this lining locally immediately above this lower area after deposition of the material to separate the lower region holding the material from the rest of the lining and permit this lower region and the material held therein to migrate automatically downward toward the center of the earth, whereby the downward widening of the lower region converts lateral compressive forces on the lower region into a vertical downward thrust force that force the separated lower region downward into the earth.