Multi-Module vs. Single-Module concept: Comparison of thermomechanical performances for the DEMO Water-Cooled Lithium Lead breeding blanket

Within the framework of EUROfusion R&D activity an intense research campaign has been performed at the University of Palermo, in close cooperation with ENEA labs and KIT, in order to compare the thermomechanical performances of the Back Supporting Structure (BSS) of Multi-Module and Single-Module concepts of DEMO Water-Cooled Lithium Lead breeding blanket (WCLL). To this purpose, detailed 3D models of the DEMO WCLL right inboard and central outboard segments, including detailed BSS and simplified First Wall and structures according to the two concepts, have been set-up. The study has been performed considering the Normal Operation and Central Major Disruption steady state loading scenarios. In particular, the former scenario implies the thermomechanical loads arising under reference nominal conditions whereas the latter scenario deals with the loading conditions induced by a plasma disruption, taking into account both Lorentz's and Maxwell's electromagnetic forces and moments. A theoretical-numerical approach, based on the Finite Element Method (FEM), has been followed and the qualified Abaqus v. 6.14 commercial FEM code has been adopted. The obtained thermo-mechanical results have been assessed in order to verify their compliance with the design criteria foreseen for the structural material. To this purpose, a stress linearization procedure has been performed along the most critical paths located within the BSS structure, in order to check the fulfilment of the rules prescribed by the SDC-IC structural design code. The obtained results are herewith presented and critically discussed.