RESUMO
A strategy for waste disposal is proposed in which the repository would be situated in a crystalline rock mass beneath a blanket of sedimentary rocks whose ground-water flow characteristics are well understood. Such an approach exemplifies the concept of multiple barriers to the isolation of radioactive wastes from the biosphere. This strategy has the advantages that (i) ground-water flow within the sedimentary rocks can be investigated and modeled by conventional, well-under-stood theory and technology; (ii) under favorable circumstances, the flow system operates as an active barrier, so that a long migration path and extremely low flow rate to the biosphere can be assured; and (iii) since, in many locations, ground water is nonpotable, the possibility of future human intrusion can be minimized.
