Assessment of the Geological Disposal of Carbon Dioxide and Radioactive Waste in Brazil, and Some Comparative Aspects of Their Disposal in Argentina

摘要

Brazil and Argentina have a huge geological capacity for carbon dioxide (CO_2) and radioactive waste (RW) disposal. Projects for carbon capture and disposal in coal seams and depleted oilfields have important economic benefits, significantly enhancing gas and oil productivity through enhanced coalbed methane and enhanced oil recovery, respectively. In Brazil and South America as a whole, saline aquifers have the greatest storage capacity and thus the greatest potential for CO_2 disposal. Despite the costs of CO_2 capture, transport, injection and monitoring in saline aquifers (at present, without direct financial returns), these projects protect the atmosphere by reducing the amount of greenhouse gas emissions. Disposal of RW in deep geological repositories raises the environmental protection issue of preventing RW from nuclear power plants from causing underground (deep aquifers) and surface contamination. In both CO_2 and RW disposal, the long-term (millennial) safety of underground isolation in deep geological repositories must be assured. Thus, in selecting geological sites for permanent CO_2 and RW disposal, the following should be considered: (1) the occurrence of caprocks to prevent leakage; (2) the structural and geological context (stable regions without earthquake hazards); (3) the disposal capacity; and (4) the cost-efficiency of projects. The definition and characterization of disposal sites is a key question for the energy supply and the geopolitical and environmental security of all Latin American developing countries.