Experiments were performed to study the long-term reactions of radioactive materials that would be produced in the nuclear chemical mining of chalcopyrite copper ore. These reactions were carried out in autoclaves for up to eight months at 2.76 MPa of oxygen and 363 K. Dissolving rates of radioactive glass in copper-leaching product solutions were determined by the gamma-counting of solution aliquots. The glass decomposition rate was linear at approximately 1 x 10/sup -10/ kg/s.m/sup 2/. A radioactive tracer technique was used to study the extent of sorption of seven fission product nuclides on ore and decomposition products during leaching as functions of ore particle size, solution composition, pH, and liquid/solid ratio. The distribution of radionuclides between solid and liquid phases was determined. In general, the solids continue to concentrate the radioactivity from the liquid for long periods of time, as the ore and gangue surfaces change in the complex chemical and physical processes of leaching. Solid phases in a nuclear chemical mine would therefore effectively decontaminate the leach liquor. Leaching time and pH are variables that could be used to control the level of activity in solution. (auth)