Nuclear Technology / Volume 165 / Number 1 / January 2009 / Pages 96-110
Technical Paper / Materials for Nuclear Systems
Fast reactor metal fuels containing minor actinides (MAs) Np, Am, and Cm and/or rare earths (REs) have been irradiated in the fast reactor PHÉNIX to examine the effects of adding those elements on metal fuel irradiation behavior. In this experiment, two MA-containing metal fuel pins, in which the test alloys U-19Pu-10Zr-2MA-2RE and U-19Pu-10Zr-5MA/U-19Pu-10Zr-5MA-5RE (wt%) were loaded into part of a standard U-19Pu-10Zr alloy fuel stack, and a reference fuel pin of U-19Pu-10Zr alloy without MAs or REs was set in an irradiation capsule. Two other capsules with this same configuration are also irradiated. Postirradiation examinations are conducted at ~2.5, ~7, and ~11 at.% burnup. For the low-burnup fuel pins, nondestructive tests after irradiation have been performed, and the integrity of the pins was confirmed. The irradiation behavior of MA-containing metal fuels up to 2.5 at.% burnup was analyzed using the ALFUS code. The calculation results, such as the axial swelling distribution of a fuel slug or the extrusion behavior of bond sodium to the gas plenum, are consistent with the measurement data regardless of the addition of MAs and REs to the U-Pu-Zr alloy fuels. This observation result indicates that the macroscopic irradiation behavior of U-Pu-Zr fuels containing MAs and REs of 5 wt% or less is similar to that of U-Pu-Zr fuels up to ~2.5 at.% burnup.