Feasibility Analysis of the Multilayer and Multicanister Concepts for a Geological Spent Fuel Repository

For a spent fuel repository, the possible application of the concepts of a multilayer repository with a two- or three-story disposal tunnel and a multicanister repository in which two or three canisters are emplaced in a deposition hole is assessed from the viewpoint of temperature, mechanical stability, and nuclear criticality. The results show that the concepts of multilayer and multicanister repositories are applicable to the geological repository without deterioration of the mechanical stability and nuclear criticality safety. Their adoption in the spent fuel repository can improve the disposal density up to 200% to 400% depending on the applied peak temperature limit under the given thermal constraint and site conditions.