Experimental study on particle crushing and pressure drop characteristics of Li4SiO4 breeder pebble beds

• Uniaxial compression tests were conducted on Li₄SiO₄ breeder pebble beds, and the pebble breakage rate of the beds under various compression conditions was statistically analyzed. • Based on the obtained particle breakage conditions, the helium pressure drop in breeder pebble beds under varying breakage scenarios was measured. • For Li₄SiO₄ breeder pebble beds with breakage ratios up to 15 %, the Ergun equation remains effective in predicting the helium pressure drop within the particle crushing pebble beds. During long-term operation of tritium breeding blankets in fusion reactors, breeder particles are subjected to both irradiation and thermal stress, which can lead to particle fracture, thereby affecting the structural integrity of the pebble bed and the tritium breeding performance. This study investigates the fracture behavior of Li₄SiO₄ particles used in Helium-Cooled Ceramic Breeder (HCCB) blankets. In this work, Uniaxial cyclic compression tests were performed on breeder pebble beds to evaluate their mechanical response under different stress and temperature conditions. The particle breakage rate and fragment size distribution were obtained through sieving. Results indicated that increasing compressive stress and temperature led to higher breakage rates and a greater mass fraction of small fragments. Building on these fragmentation characteristics, multiple crushed packed beds with varying breakage rates (3–15%) and size distributions were configured to investigate particle breakage effects on purge-gas pressure drops, revealing that the helium pressure drop increases with the breakage rate. Crucially, the Ergun equation reliably predicted pressure drops for breakage rates ≤15%, with a maximum deviation of 10.6% under extreme fragmentation.