The problem of isolating radioactive wastes from the biosphere presents specialists in the fields of earth sciences with some of the most complicated problems they have ever encountered. This is especially true for high level waste (HLW) which must be isolated in the underground and away from the biosphere for thousands of years.

The first worldwide review of geological problems in radioactive waste isolation was published by the Ernest Orlando Lawrence Berkeley National Laboratory (Berkeley Lab) in 1991 (Witherspoon, 1991). This review was a compilation of reports that had been submitted to a workshop held in conjunction with the 28th International Geological Congress that took place July 9Ð19, 1989, in Washington, D.C.