Patent Number: 
Section: claims

1. A system for emergency in-situ subsurface isolation of mobile radioactive material from a source of the mobile radioactive material, the system comprising:a borehole located in proximity to, and in flow communication with, the source of mobile radioactive material, the borehole being at a depth suitable for safely isolating the mobile radioactive material;a conduit system connecting the source of the mobile radioactive material and the borehole and;a prepared first man-made vertical-oriented gravity fracture located in a surrounding rock formation below and in communication with a bottom end of the borehole and available to receive the mobile radioactive material exiting the bottom end of the borehole during the emergency, the first man-made vertical-oriented gravity fracture made using a slurry containing a weighting material, the slurry being denser than the surrounding rock formation and not including the mobile radioactive material;wherein during the emergency, the mobile radioactive material enters the borehole and from the borehole into the man-made vertical-oriented gravity fracture. 2. A method according to claim 1, wherein the slurry has an absolute tendency to travel vertically downward in the surrounding rock formation. 3. A system according to claim 1, wherein at least a portion of the mobile radioactive material is mixed with a weighting material to produce a fluid or a slurry sufficiently dense to cause additional vertical downward propagation of the man-made vertical-oriented gravity fracture. 4. A system according to claim 1, further comprising a layer of porous material located at the bottom end of the borehole. 5. A system according to claim 1, further comprising artificial lift pumping means located at the bottom end of the borehole.