Radial redistribution of actinides in irradiated FR-MOX fuels

The redistributions of neptunium, plutonium and americium during two kinds of short-term irradiation tests for 10 min and 24 h at high linear heating rate around 430 W cm−1 were studied in the uranium and plutonium mixed oxide fuel containing Am and/or Np. It was found in the irradiation test for 24 h that the concentrations of Pu and Am increased toward the central void, but there was no change in the concentration of Np. The obtained experimental redistributions of Am and Pu were analyzed, based on both pore migration and thermal diffusion models. As a result, the calculated redistributions of Pu and Am showed good agreements with the experimentally obtained ones.