Thermal Impact of Waste Emplacement and Surface Cooling Associated with Geologic Disposal of Nuclear Waste.

摘要

This report studies the thermal effects associated with the emplacement of aged radioactive waste in a geologic repository, in particular; the waste characteristics, repository structure, and rock properties controlling the thermally induced effects, the current knowledge of the thermal, thermomechanical, and thermohydrologic impacts, determined mainly on the basis of previous studies that assume 10-year-old wastes, the thermal criteria used to determine the repository waste loading densities, and the technical advantages and disadvantages of surface cooling of the wastes prior to disposal as a means of mitigating the thermal impacts. The waste loading densities determined by repository designs for 10-year-old wastes are extended to older wastes using the near-field thermomechanical criteria based on room stability considerations. The extension of the surface cooling period from 10 years to longer periods can lower the near-field thermal impact but have only modest long-term effects for spent fuel based on far-field thermomechanical and thermohydrologic considerations. More significant long-term effects can be achieved by surface cooling of reprocessed high-level waste.