SIZE DEPENDENT CRUSH ANALYSIS OF LITHIUM ORTHOSILICATE PEBBLES∗

Crushing strength of the breeder materials (lithium orthosilicate, Li4SiO4 or OSi) in the form of peb-bles to be used for EU solid breeder concept is investigated. The pebbles are fabricated using a melt-spray method and hence a size variation in the pebbles produced is expected. The knowledge of the mechanical integrity (crush strength) of the pebbles is important for a successful design of breeder blanket. In this paper, we present the ex-perimental results of the crush (failure) loads for spherical OSi pebbles of different diameters rang-ing from 250 µm to 800 µm. The ultimate failure load for each size shows a Weibull distribution. Furthermore, the mean crush load increases with increase in pebble diameter. It is also observed that the level of opacity of the pebble influences the crush load significantly. The experimental data presented in this paper and the associated analysis could possibly help us to develop a framework for simulating a crushable polydisperse pebble assem-bly using discrete element method. I