Fusion Science and Technology / Volume 62 / Number 1 / July 2012 / Pages 185-189
Blanket Materials Technology / Proceedings of the Fifteenth International Conference on Fusion Reactor Materials, Part A: Fusion Technology
Lithium orthosilicate (Li4SiO4) pebbles are the primary candidate breeder for the Korean Helium-Cooled Solid Breeder test blanket module because of their superior overall performance qualities such as reasonable lithium atom density, favorable tritium release behavior, low activation property, and chemical stability. The aim of this study is to develop a fabrication method for Li4SiO4 pebbles with high sphericity and stable micro-crystalline structure. Li4SiO4 slurry was prepared by mixing Li4SiO4 powder and polyvinyl alcohol (PVA) solution. The Li4SiO4 gel-spheres were made by dropping slurry mixture into hydrogen peroxide (H2O2) solution. The gel-spheres were floated up to the surface of the H2O2 solution after staying at the bottom for a while and then aged on the surface of the H2O2 solution. The gel-spheres were dried at room temperature and sintered at several temperatures for 4 hours in air atmosphere. The sintered pebbles kept the shape of spheres during the sintering process in spite of shrinkage. Furthermore, the pebbles had relatively high sphericity. Also, the effects of PVA content and sintering temperature on the properties of the Li4SiO4 pebbles were investigated.