Fabrication and characterization of Be-Zr-Ti ternary beryllide pebbles

Abstract

Beryllium intermetallic compounds (beryllides) such as Be12Ti, Be13Zr and Be12V are the most promising advanced neutron multipliers for DEMO reactors (DEMOnstration fusion power plant). Plasma sintering and the rotating electrode methods for the fabrication of beryllide rods and pebbles have been established and a new chemical composition has been suggested as development of more advanced neutron multipliers. By using these methods, preliminary synthesis of the ternary Be-Zr-Ti pebbles has been conducted. In the Be13Zr1-xTix composition (x = 0.1, 0.3, 0.5, 0.7 and 0.9), some of the pebbles showed the existence of a Be phase on the surface, which results in mass gain and hydrogen generation. Ternary beryllide pebbles were successfully fabricated from mixtures of Be12Ti and Be13Zr with ratios of 1:1, 1:0.6, 1:0.4, 1:0.2 and 1:0.1. As a result of the SEM observations, it was clear that no Be phase was found on the surface of the pebbles despite of the fact that some fractions were identified inside the pebbles. For stability with 1% water vapor of as-received ternary pebbles at high temperatures, it was clear that those indicated much lower hydrogen generation, which corresponds to much higher stability than Be pebbles at high temperatures.