Geologic Disposal of High-Level Radioactive Waste: Status, Key Issues, and Trends

The permanent disposal of high-level radioactive waste is one of the major technical hurdles that must be addressed if electrical power production by nuclear energy is to remain viable. The main challenge is that the waste must be effectively isolated from interactions with the biosphere for hundreds of thousands of years. A number of permanent disposal options have been proposed and reviewed by various countries and scientific organizations during the past few decades, and there appears to be a consensus today that mined geologic disposal is the most practical and effective method. Several variations on mined geologic disposal are being intensively studied by waste-producing countries. These investigations address a wide range of scientific questions, such as the behavior of geological and engineered barriers over time and the use of quantitative modeling and/or qualitative observational evidence to demonstrate the safety of disposal. The present review provides an overview of current approaches, scientific issues, and safety assessments related to mined geologic repositories for high-level radioactive waste.