He migration in implanted UO2 sintered disks

The behaviour of helium implanted in sintered uranium dioxide disks has been investigated as a function of annealing temperature. UO2 disks have been implanted with 1 MeV 3He ions at a fluence of 1 × 1016 3He cm−2 using a Van der Graaff accelerator. These implantation conditions lead to a local helium concentration of 0.2 at.% at a depth of 1.9 μm in UO2. The 3He(d,α)1H Nuclear Reaction Analysis method was used to determine the helium depth profile after the various annealing stages. The experimental results measured after 1100 °C anneal were analysed using a simple model which satisfactorily reproduces the observed helium depth profile changes. The intragranular helium diffusion coefficient is estimated and the result is assessed against other data published in the open literature.