The report contains an evaluation of the state of knowledge in the earth sciences relevant to environmental aspects of the disposal of high-level radioactive wastes, by deep burial on the continents. A consideration must be given a time scale of hundreds of thousands to a few million years, but special attention must be given to the dangers of leakage over shorter terms up to a thousand years, when the levels of radioactivity are highest. A basic problem in storage of radioactive wastes stems from the addition of radioactive heat to the normal geothermal temperatures at depths on the order of 500 meters. Storage should be in an area that is subject neither to frequent, high-energy earth quakes nor to volcanic eruptions. A rock environment is required that is sealable and has a minimal permeability for fluids and radionuclides that might become dissolved in them. The most suitable rocks seem to be salt, shale, basalt, and certain granitic rocks, but some anhydrite and impereable tuffs should be considered.

Includes bibliographical references (p. 47-48).