[en] In this paper, recent numerical modeling and experiment work for predicting the effective thermal and mechanical properties of solid breeder blanket pebble bed materials is presented. The numerical modeling is based on the micro-mechanics displacement method in conjunction with an iterative process of successive releasing of the contact force of particles. Initial and final packed states for particle assembly and the contact forces for particles have been studied. In addition, a test article has been constructed to measure the thermal stress induced by the thermal expansion of the solid particle and to estimate the characteristic properties of particle materials. Corresponding experiments are carried out with aluminum and Li₂ZrO₃ pebble beds. Empirical correlations for the moduli of deformation are presented. These experiment data are compared with the numerical modeling results