The strength of advanced ceramic breeder pebbles, consisting of Li4SiO4 and Li2TiO3 as well as lithium excessive Li2TiO3 was investigated with the focus on the influence of different relevant fabrication methods, compositions and after thermal annealing. Within this work, the failure mechanisms of the pebbles were determined as well as their causes. Regarding the long term stability of the pebbles it is clear that with the use of a suitable composition significant improvements can be achieved.