CONTINENTAL-SHELF SEABED DISPOSAL: DISPOSAL OF NON-REPOSITORY RADIOACTIVE WASTES FOR A WORLD OF 10 BILLION PEOPLE

摘要

Shallow-land disposal has been traditionally used for radioactive wastes not requiring deep geological disposal. However, this strategy becomes more problematic for many countries in a world with 10 billion people, mostly within 100 kilometers of the ocean, and a changing climate. Climate change implies changing rainfall that can impact shallow-land burial site performance. High population densities imply expensive disposal sites or long transport distances to disposal sites. The lack of international disposal sites limits countries to their own territories. Alternative options are needed. Advancing technologies and better understandings of how radioactive disposal sites perform are creating a new disposal option: continental-shelf sub-seabed disposal. Waste is buried 5 to 20 meters under the seabed in large concrete barges and other structures. Because of limited use of the sub-seabed, it is the most available nearby land for a disposal site for most of the world's population. The expectation is that sub-seabed disposal will have better performance than non-repository land-based disposal sites and approach that of geological repositories because of a set of natural and engineering barriers. The performance is based on characteristics of the sub-seabed and new isolation technologies. The sub-seabed has limited or no groundwater movement, it is not impacted by climate change, and provides redundant barriers to radionuclide releases. Engineered features such as saltcrete can enhance performance. Saltcrete is incorporated into the disposal site to (1) assure water densities in the disposal zone are higher than seawater with isolation from seawater by density, (2) preserve wastes in an unchanged state over time (minimize gas generation), and (3) avoid colloid formation. Oil industry engineering advances provide the required technology.