Drawbacks of U-Mo dispersion fuel for research reactor and consideration on the solutions

The irradiation tests, which have been performed by KAERI, ANL, CERCA, and AECL, showed that the swelling by the interaction between aluminum matrix and fuel particles was severe and sensitive to the fuel meat temperature. However, the swelling by the bubble formation of fission gas was examined to be very small as negligible. The U-Mo dispersion fuel was accessed to be applicable to the thin plate type fuel with very short heat diffusion distance of less than 0.5 mm, while the rod type fuel with long heat diffusion distance of more than 3.0 mm is assumed to be limited in using U-Mo dispersion fuel with high uranium density. Especially pure U-Mo material in fuel particle was investigated to have a stable irradiation behavior up to relatively high temperature. Accordingly it is expected that a fuel designed using thin U-Mo plate to minimize the interface temperature would be applicable. In addition, the thick formation of bohemite at the cladding surface in case of high power irradiation was observed to affect the fuel meat temperature increase. To improve the corrosion-resistant property of cladding surface efforts such as coating the cladding surface or using more corrosion-resistant aluminum alloy are required