Experimental Study on Mechanical Characteristics of Li2tio3 Pebble Beds Under Cyclic Loading

Abstract

The lithium titanate (Li 2 TiO 3 ) ceramic pebble bed is one of the main tritium breeder candidates in solid blankets of fusion reactors. Under extreme operation conditions of fusion blankets, such as neutron irradiation, high temperature, structural material extrusion, and stress concentration, the mechanical characteristics of tritium breeding pebble beds not only affect the mechanical performance of the blanket but also affect the tritium production and extraction. Therefore, an experimental apparatus was built to characterize the mechanical behavior of 0.47 mm and 0.99 mm Li 2 TiO 3 pebble beds. The uniaxial compression test was performed under the cyclic mechanical load of 4 MPa, 6 MPa, and 8 MPa, respectively. It was shown that large irreversible residual strain appeared in the Li 2 TiO 3 pebble bed with the increase of loading cycles, and the mechanical characteristics of pebble beds are greatly affected by different mechanical loads and particle sizes. The current results can provide relevant experimental data support for the design of fusion blankets.

Keywords: Solid breeding blanket, Li2TiO3 pebble bed, mechanical characteristics, uniaxial compression test