Compatibility of tritium breeders and neutron multipliers as a mixed-pebble packing concept for JA DEMO fusion reactor

To verify the feasibility of a mixed-pebbles packing concept, the high-temperature compatibility of beryllide (Be12V) and Li2TiO3 pebbles with 1mm diameter at high temperatures, 973 and 1173 K was investigated. It was evident from the x-ray diffraction and scanning electron microscopy observations that the Li2TiO3 pebbles exhibited no remarkable change after the compatibility tests at 973 and 1173 K. However, inductively coupled plasma mass spectrometry analysis revealed that Be12V pebbles contained a small amount of Li as an impurity, revealing that as time increased, the Li amount in the Be12V pebbles increased with parabolic reaction after the compatibility tests. Moreover, the contact number and area were evaluated to be 24 points and 38.61 μm2, respectively by assumption that Be12V and Li2TiO3 with approximately 2.4 and 0.6 mm in diameter loaded.