In the nuclear field, the components operating in the heart of reactors require materials that can present, in time, good mechanical strength under irradiation and that, most often in an aggressive environment. Currently the 304L is widely used but has limitations and alternative material would be interesting if it had significant gains in: - The decrease in activation at end of life - The increase in corrosion resistance - Reduced unsprung weight to hold in earthquake and weight gain for the onboard reactors. Titanium and its alloys are a good candidate, and are already used by the Russians in the field of propulsion. However, there is very little data to validate this public interest. This project aims to study the behavior of titanium and its alloys by irradiating medium to determine and provide the best possible behavior. The project will: - To study the behavior at the interface fluid-metal, the hydrogen uptake. - Study the effects on mechanical properties of the damage due to irradiation to predict degradation. - Understand the effects of irradiation on alpha and beta phases existing in all titanium alloys. Experimentally, the project proposes to use a limited number of types of radiation, heavy ions, the cyclotron radiation of ARRONAX, to appraise a piece of titanium alloy irradiated with neutrons and already completed by calculation for extrapolate the behavior more intense radiation. The entire study will use 304L steel as a base reference to compare with titanium alloys. Several industrial and academic players differ intervene to gain access to all relevant factors under study, and a large number of characterizations will be conducted for the full view before and after irradiation of the samples tested. If the titanium alloys are attractive, industrial uses will be considered in the internal structure of upper tank, steam generators, packaging containers of fuel new and used, as well as in other applications.