Sintered He-implanted samples were studied by using nuclear reaction analysis, before and after heavy-ion bombardment and annealing at 800 or 1100C. The results showed that the heavy-ion bombardment did not produce any measurable long-range movement of He atoms. However, the ion bombardment affected the behavior of He during subsequent annealing. For 800C annealing, a reduced mobility of He in ion-bombarded samples was attributed to an enhanced He-atom segregation produced by the bombardment. For 1100C annealing, an initial heavy-ion bombardment appeared to produce a greater than expected movement of He within the bulk of the sample which was taken to be an indication of defect-assisted He diffusion. Thermal diffusion coefficients, for 800 and 1100C, were deduced on the basis of a 1-dimensional diffusion model.

A NRA Study of Temperature and Heavy Ion Irradiation Effects on Helium Migration in Sintered Uranium Dioxide. G.Martin, P.Garcia, H.Labrim, T.Sauvage, G.Carlot, P.Desgardin, M.F.Barthe, J.P.Piron: Journal of Nuclear Materials, 2006, 357[1-3], 198-205