Titanium alloys could be good candidates for pressurised water reactor (PWR) primary circuit structure components because of their low neutron activation and their good corrosion behavior. This study focuses on the determination of the kinetics and mechanisms of corrosion and hydrogen uptake of titanium alloys in PWR primary water conditions. Specimens of three different titanium alloys have been exposed to media in static autoclaves or in a corrosion loop: T40 (alpha phase), TA6V (4% beta phase) and Ti1023 (40% beta phase). Stainless steel specimens have also been exposed in order to compare their corrosion resistance to titanium alloys one in the same conditions. After exposures during 0.3, 0.6, 1.2, 2.4 and 4.8 months, the oxide layers grown on titanium alloys specimens were analyzed by scanning electron microscopy (SEM), Raman spectroscopy, X-ray photoelectron spectrometry (XPS) and glow discharge - optical emission spectroscopy (GD-OES). The evolution with exposure time of the thickness, composition and structure of the oxide layer enables the first establishment of oxidation kinetics. Some growth mechanisms can also be suggested in agreement with these observations. First results show that samples surfaces are rapidly covered with a dense oxide layer (few 10 nm thick) made of anatase TiO_2, itself covered by anatase and iron oxide crystallites (from 100 nm to few μm thick), which most probably originate from oxide dissolution / precipitation phenomenon. Moreover, first results indicate that oxidation of alloys (in terms of weight gain and oxide thickness) increase with increasing beta phase rate. Besides this oxide characterization study, the hydrogen uptake kinetics by the alloy were estimated thanks to time-sampling for which the H amount was determined by total melting extraction technique, showing a slow but linear hydrogen enrichment with time. Hydrogen uptake of alloys increase with increasing beta phase rate in same way than oxidation, suggesting that hydrogen uptake was due to water reduction reaction. Moreover, GD-OES and thermal desorption spectrometry analysis have shown that hydrogen was mainly located in the alloy even if there was a local accumulation of hydrogen in the alloy at the oxide/alloy interface. This accumulation of hydrogen at the interface will be discussed in terms of trapping at vacancies, or dislocations, orhydrides.
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