Effect of Gd(2)O(3) dispersion on the thermal conductivity of UO(2)

• Published in: Journal of nuclear science and technology Vol. 46; no. 7; pp. 673 - 676
• Main Authors: Iwasaki, Kouta, Matsui, Tsuneo, Yanai, Koichi, Yuda, Ryouichi, Arita, Yuji, Nagasaki, Takanori, Yokoyama, Noboru, Tokura, Ichiro, Une, Katsumi, Harada, Kenichi
• Format: Journal Article
• Language: English
• Published: 01.07.2009
• ISSN: 0022-3131

10wt% Gd(2)O(3)-dispersed UO(2) pellets, in which Gd(2)O(3) particles are dispersed in UO(2) matrix, were prepared, and the thermal conductivity was investigated. The Gd(2)O(3)-dispersed UO(2) pellets consisted of Gd(2)O(3), UO(2), and a Gd-U-O phase that was formed by diffusion of U ions into Gd(2)O(3) particles during the sintering process. In addition, pores were mainly distributed at the boundary between the Gd(2)0(3) particles and the UO(2) matrix. The thermal conductivity of 10 wt% Gd(2)O(3)-dispersed UO(2) decreased with temperature (5.8-2.7 Wm(-1)K(-1) from 300 to 1273 K) and was larger than that of (U,Gd)O(2) solid solutions (3.8-2.6Wm(-1)K(-1)) with the same Gd(2)O(3) content. The increase in the thermal conductivity by Gd(2)O(3) dispersion was attributable to the reduction in phonon-point defect scattering in the UO(2) matrix. Dispersion of Gd(2)O(3) particles was effective in improving the thermal conductivity of Gd(2)O(3)-UO(2) fuel pellets.