Abstracts and Available Papers Presented at the
1997 International RERTR Meeting

Thermal Compatibility of U3Si2 Fuels Prepared
with Centrifugally Atomized powder

Ki Hwan Kim, Don Bae Lee, Jong Man Park, Hee Dae Park
and Chang Kyu Kim

Korea Atomic Energy Research Institute,
150 Dukjin-dong, Yusong-gu,
Taejon 305-353, South Korea

ABSTRACT

Thermal compatibility of atomized U3Si2 dispersed fuel meats has been characterized and compared with comminuted U₃Si₂ fuel meats. U₃Si₂ fuel samples from the comminuted powder showed a larger volume increase compared with those from the atomized powder, irrespective of heat treatment temperature and volume fraction of U3Si2 powder. The possible reason for this seems to be as follows; 1) the smaller specific surface area of the atomized spherical powder compared to the irregular comminuted powder is related to the reduction of volume change in the fuel meat in terms of the diffusion-controlled process, 2) the comminuted fuel samples have higher porosity than the atomized fuel samples, which reduces the restraint force of the fuel meat on swelling, 3) U₃Si₂ fuel samples from the comminuted powder have exclusive penetration paths, that is, deformation zones or cracks, originated from the comminution and extrusion process, leaving a network of unreacted islands. There could be two pronounced penetration paths of aluminum into atomized U₃Si₂ powder; 1) through the phase interface, leaving an island with a large 'kernel-like' structure, 2) along the grain boundary, leaving several unreacted islands.