Damage generated by MeV-ion beams on titanium surface in oxidizing environment

International audienc

Ellipsometric study of the oxides formed on titanium and zirconium under argon irradiation

International audienc

Corrosion of titanium and zirconium under Ar irradiation in the low MeV range: an XPS and SE study

International audienc

Radiation damage induced at the surface of titanium by argon ions of a few MeV

Oxide films thermally grown on titanium in a weakly oxidizing environment (5 × 10−3 Pa of dry air) under irradiation with 2, 4 and 9 MeV argon have been studied. The AFM study reveals a cratering effect of 2, 4 and 9 MeV argon and a significant surface roughening effect of 2 MeV argon, both effects being largely unexpected in this energy range. The XPS analysis shows that the TiO2 stoichiometry of the superficial oxide film is fairly well maintained under argon irradiation. The Spectroscopic Ellipsometry analysis reveals an oxide film thickness multiplied by a factor of three under irradiation with 2 MeV argon by comparison with 9 MeV argon, the irradiation effect on oxide growth remaining very limited for 4 or 9 MeV argon. The possible role of the electronic but most certainly of the nuclear energy losses on the surface damage mechanism are discussed. It is suggested that the oxidizing environment is necessary to freeze the instantaneous surface damage and permits the post-mortem observation

Evolutions structurales et microstructurales dans les matériaux du nucléaire.

The study of nanostructured and conventional materials for nuclear applications can be performed using laboratory diffraction in conjunction with neutron and synchrotron experiments. A selection of results obtained on several classes of materials of nuclear interest is displayed in the panels of this poster, illustrating how accurate and quantitative information can be extracted about symmetry, lattice strain, atomic positions, crystallite size and microstrain. Our investigations at the LRC Carmen are focused at tracking the structural and microstructural changes produced by irradiation

Radioactive waste conditioning: the choice of the cement matrix versus irradiation

International audienceThe aim of this study is to compare the behavior of Portland and Ciment Fondu® cement under irradiation taking into account both real cement pastes and synthetic hydrates. First, γ-irradiations were performed using a 60 Co source (dose rate: 0.17-0.25 Gy.s-1, dose: up to 500×10 3 Gy). Thermogravimetric analysis measurements were performed in order to determine the amount and the type of water involved. H2 gas production was measured by gas chromatography. Regardless of the water to cement ratio (W/C) chosen (0.2, 0.4 and 0.6), it is shown that Ciment Fondu® pastes produce less H2 under irradiation. Moreover, the H2 production of portlandite and gibbsite, constituent hydrates of Portland and Ciment Fondu® cements respectively, shows that the amount of gas produced depends on the hydrate nature. Secondly, portlandite and gibbsite were electron-irradiated up to 300 MGy and 3 GGy using the LSI SIRIUS accelerator platform. X-Ray Diffraction analyses were performed before and after irradiation in order to investigate structural damage. Only limited structural disorder was observed, which confirms the good stability of both hydrates under present irradiation conditions