ABSTRACT
The use of salt structures for the disposal of low, medium, and high level radioactive waste makes it necessary to perform safety analyses, in particular geomechanical model calculations, to demonstrate the stability of the repository and the integrity of the salt barrier. The analysis should comprise all necessary steps used for geoscientific investigations, from geological exploration to numerical modeling. The different steps like geological-geophysical exploration and geological modeling, classification of salt layers, constitutive modeling and parameter determination, definition of mechanical and thermal loading, formulation of stability and integrity criteria as well as evaluation of numerical results are described. Two examples of geomechanical safety analyses of radioactive waste repositories in salt structures are discussed. The first example describes the Morsleben repository used for the disposal of LLW and MLW and covers the evaluation of the stability of the mine and the integrity of the salt barrier affected mechanically by large old mining rooms. The second example considers a fictive HLW repository in the Gorleben salt dome and illustrates the thermomechanical response and integrity of the salt barrier under thermal loading caused by the heat-generating waste.
