Study on the chemical compatibility between Li2TiO3 ceramic pebbles and diverse advanced structural materials

Abstract

AbstractThe tritium breeder and structural materials are necessary components in the blanket to realize tritium (T) self‐sustainment of nuclear fusion. The long‐term exposure between tritium breeders and structural materials will cause surface corrosion in irradiation environments and then further affect the tritium release behavior. In this study, chemical compatibility between Li2TiO3 ceramic pebbles and advanced structural materials was studied systematically at 700 °C for 300 h under He+0.1 % H2 environment, respectively. The color of the Li2TiO3 ceramic pebbles changes from white to dark grey and black. Moreover, the grain size of Li2TiO3 ceramic pebbles increases to more than 5 μm, and the crushing load decreased slightly. For the structural materials, the Al‐rich oxide layer with about 188.7 nm of 14Cr‐5Al oxide dispersion strengthened (ODS) steel and Cr‐Fe rich oxide layer with about 1.04 μm of 14Cr‐ODS steel were observed on the cross‐section. The effective diffusion coefficient of O element in Li2TiO3 ceramic moved into ODS steel at 700 °C was calculated to be 3.3 × 10−16cm2/s and 1.02 × 10−14 cm2/s. Unfortunately, when SiC ceramics were contacted with the pebbles, the crystal phase transformed into SiO2, which severely limits its application. Therefore, these results will provide guidance for the selection of structural materials in the future.