Thermo-mechanical analysis of pebble beds in HELICA mock-up experiments

In this investigation, a thermo-mechanical model for pebble beds and a method for the identification of the material parameters, recently developed in Forschungszentrum Karlsruhe, are adopted for the analysis of HE-FUS3 Lithium Cassette (HELICA) mock-up. A pressure-dependent thermal contact conductance model to represent the pebble–wall interactions has been implemented in the FE code ABAQUS. First, the current material model has been verified by uniaxial compression and creep experiments under a wide range of temperature fields, and good agreement between experiments and theory has been achieved. The HELICA mock-up has been modelled by 2D generalized plane strain elements, and analyzed in ABAQUS. The results show that the temperature and mechanical fields obtained in FE analysis agree well with the measurements by thermo-couples and LVDTs located at different positions.