Thermomechanical interactions in repository design

Abstract The design goal for radioactive waste repository design is a configuration that will last a very long time and restrict radionuclide migration. Because experiments and prototype observations cannot be relied upon to ascertain fully the long-term behavior of the repository, numerical modeling has been employed in attempts to predict the future repository conditions. Unfortunately, the variability of geologic media defies accurate modeling. Models may be verified for numerical accuracy but may not be validated by actual observations of the phenomena to the degree desired. Hence, there is a need to establish a strategy for design and performance assessment that does not fully rely on the validation of models. A strategy proposed here relies on an identification of plausible and possible failure modes rather than on a reliable prediction of aspects of repository behavior. Once failure modes have been identified, efforts can be concentrated on dealing with them, either by assessing their (low) probability of occurrence, or by preventing these failure modes by appropriate repository design.