10 wt% 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 O 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 W m À1 K À1 from 300 to 1273 K) and was larger than that of (U,Gd)O 2 solid solutions (3.8-2.6 W m À1 K À1 ) 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.
10 wt% 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 O 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 W m À1 K À1 from 300 to 1273 K) and was larger than that of (U,Gd)O 2 solid solutions (3.8-2.6 W m À1 K À1 ) 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.
The purpose of the study is to develop technology for pre-treatment of oxide fuel reprocessing through pyroprocess. In the pre-treatment process, it is necessary to reduce actinide oxide to metallic form. This paper outlines some experimental results of uranium oxide reduction and recovery of refined metallic uranium in electrorefming. Both uranium oxide granules and pellets were used for the experiments. Uranium oxide granules was completely reduced by lithium in several hours at 650°C. Reduced uranium pellets by about 70% provided a simulation of partial reduction for the process flow design. Almost all adherent residues of Li and Li 2 0 were successfully washed out with fresh Liel salt. During electrorefming, metallic uranium deposited on the iron cathode as expected. The recovery efficiencies of metallic uranium from reduced uranium oxide granules and from pellets were about 90% and 50%, respectively. The mass balance data provided the technical bases of Li reduction and refming process flow for design.
In the fuel fabrication of metallic fuel cycle, a molten fuel alloy is injected into a bundle of molds. After de-molding, the consolidated fuel slugs are processed to appropriate shapes. The key technology is injection casting for these processing steps. The technology development on fabrication of U-Zr binary alloy and qualification experiences are outlined in this paper. The design experiences of an engineering scale injection casting apparatus are also described. As the results of these experiences, it was demonstrated that the injection casting process is compact and easy to operate.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.