One‐step fabrication of Li2TiO3 ceramic pebbles using pulsed YAG laser

Abstract

AbstractA large amount of Li‐containing ceramic breeder pebbles is packed in the solid breeding blanket of a nuclear fusion reactor. Several pebble fabrication technologies have been proposed in previous studies, including wet process, emulsion method, extrusion spheronization, additive manufacturing, and melt process. However, a simple, energy‐effective, and scalable fabrication technology remains to be developed for the automated mass production and reprocessing of used radioactive pebbles post‐operation. Selective laser melting potentially enables the quick and automated fabrication of breeder pebbles. Herein, we employ a high‐power density pulse laser to produce ceramic breeder pebbles. A pulsed YAG laser was irradiated over a lithium metatitanate (Li2TiO3) powder bed in air, and the corresponding temperature was monitored using fiber‐type infrared pyrometers. Spherical Li2TiO3 pebbles were successfully fabricated in a single step with an average diameter of 0.78 ± 0.13 μm and the sintering density of 87.4% ± 5.6% (input power: 7.9 J/pulse). The irradiated Li2TiO3 powder melted and turned spherical under surface tension and rapidly solidified, resulting in uniaxial fine grains and a decrease in the degree of long‐range cation ordering.