Irradiation behavior of high density uranium alloy dispersion fuels

The screening irradiation test of high density uranium alloy dispersion fuels up to 40 % burn-up at ATR revealed that U-10Mo, U-6Mo-0.6Ru and U-6Mo-1Pt alloys possess stable irradiation performance but the U-Nb-Zr alloy dispersion fuel showed an extensive reaction with aluminum matrix as well as a lot of large pores. There appeared to be some difference in irradiation swelling behavior between the comminuted and the atomized U-10Mo alloy dispersion fuels. In the case of the comminuted dispersion fuel, a large number of fine pores were distributed homogeneously in the fuel particles which is similar to the irradiation behavior of the U3Si2 fuel. However, in the atomized dispersion fuel, a few irradiation pores were observed mainly at grain boundaries. It is evaluated that the atomized dispersion fuel has better irradiation performance than the comminuted fuel. The difference in the irradiation performance between the comminuted and the atomized U-10Mo dispersion fuels, even though it is still unclear, might be related to the various defects in particles and inhomogeneous chemical composition generated during fuel powder fabrication