ABSTRACT
Another focus of the VSG is to evaluate the repository concepts with respect to their thermal response behaviour and any resulting subsurface design and design optimization needs. Therefore, Thermal-Mechanical (TM) model calculations of the design and optimization of the design layout were needed. Calculations were performed using three-dimensional models of repository emplacement areas. The models were generated using codes employing the Finite-Difference Method (FDM) as well as codes using a semi-analytical approach. Although only thermal criteria were used for evaluating and optimizing the design, a pure thermal analysis is not sufficient but rather a coupled thermal-mechanical analysis approach is required. Therefore, this paper identifies the effects of different processes, components, and parameters on the analyses, including:
− Mechanical behaviour of the host rock − Thermal behaviour of the crushed salt backfill − Effects of excavating a waste package emplace-
ment trough − Waste package spacing − Interim storage time for waste packages (aging
and cooling)
The results show that the design of repository components and systems in addition to the overall favourable geological conditions of the host formation are necessary elements for the development and optimization of the final repository design. With respect to the two basic concepts, this paper considers the concept of drift emplacement of shielded emplacement-casks type POLLUX.
