The radiation enhanced diffusion of Cl in UO2 during heavy-ion bombardment was studied. In order to simulate the behavior of 36Cl, present as an impurity in UO2, 37Cl was implanted into samples to a projected range of 200nm. The samples were then bombarded with 63.5MeV 127I using 2 fluxes and 2 temperatures and the Cl distribution was analyzed using secondary ion mass spectrometry. The results showed that, during bombardment, diffusion of the implanted Cl was enhanced and was slightly athermal with respect to pure thermal diffusion. A Cl gain of 10% accumulation near to the surface was observed at 510K. This corresponded to the displacement of pristine Cl from a region of maximum defect concentration. This behavior, and the mean value of the apparent diffusion coefficient (about 2.5 x 10−14cm2/s) found for implanted Cl, reflected the high mobility of Cl in UO2 during bombardment with fission products.

Chlorine Diffusion in Uranium Dioxide under Heavy Ion Irradiation. Y.Pipon, N.Bérerd, N.Moncoffre, C.Peaucelle, N.Toulhoat, H.Jaffrézic, L.Raimbault, P.Sainsot, G.Carlot: Nuclear Instruments and Methods in Physics Research Section B, 2007, 257[1-2], 527-31