[en] Raman spectroscopy has been used to characterize uranium hydride and deuteride. Raman shifts of UH_3 and UD_3 are evident to be inversely proportional to the square root of the mass of hydrogen isotope. The typical Raman peaks of UH_3 and UD_3 can be characterized by the mass difference of hydrogen isotope for one another. In addition, Raman peaks of uranium hydride and deuteride are identified to be at 725 and 938 cm"−"1 for UH_3 and 518 and 669 cm"−"1 for UD_3, respectively

[en] DEB hydrogen getter has been prepared by mixing DEB(ω = 75%) and Pd/C(ω = 25%) catalyst and then grinding for 5 h. The hydrogen uptake capability has been characterized by PVT method. Raman spectrum was used to characterise DEB hydrogen getter before and after hydrogen uptake process. The results show that the hydrogen uptake capacity of DEB can attain 87.5% of the theoretical value. When the uptake capacity of DEB reaches 50% of the theoretical value, the residual hydrogen content in the argon can be also controlled to less than 10 × 10^-6. Raman spectra analysis indicates that the strength of stretch vibration of the carbon-carbon triple bond gradually becomes weaker as the hydrogen uptake proceeds. (authors)

[en] The influence of carbon monooxide, oxygen on the uptake hydrogen of DEB getter was studied in this paper. The results show that CO has effect on the uptake hydrogen of DEB-Pd/C at initial stage, but O_2 has less effect. The influence of atmosphere and time on the uptake hydrogen of storage DEB getter was also studied. Storage experiment shows that hydrogen getter still has good uptake capability after storing in Np and air for l.5 years. When the content of hydrogen in the closed system approximates 50% uptake capacity of DEB, the residual hydrogen content in the argon can be controlled by less than 10 ppm. The hydrogen uptake experiment of uranium at room temperature under the moist atmosphere also indicates that the content of hydrogen in the closed system can be better controlled by DEB-Pd/C hydrogen getter. (authors)

[en] The effect of ultrasound on the efficiency of cleaning contaminants from uranium surface with supercritical carbon dioxide (SCCO₂) is studied, and the enhancement of resistibility of uranium against atmospheric corrosion by ultrasonic treatment of uranium in SCCO₂ is explored. The experimental results show that the ability and efficiency of SCCO₂ in cleaning lubricating oil, water, and triethanolamine are significantly increased. It is indicated by AES and XRD analysis for uranium specimen that nickel has been distributed into a certain depth on their surfaces after they are treated with ultrasound in SCCO₂ containing 0.5% nickel tetracarbonyl. TGA reveals that the uranium specimen treated with SCCO₂ (containing 0.5% Ni(CO)₄) in ultrasonic field has a better humid air corrosion resistance than those treated only with SCCO₂. (authors)

[en] The residual coolant on the surface of uranium after manufacture is inevitable and it will be effective on the corrosion of uranium. The coolant contamination has been cleaned by supercritical carbon dioxide (SCCO₂), SCCO₂ + methanol and SCCO₂ + ethanol. IR and Raman spectra have been used to investigate the cleaning efficiency for residual coolant in this study. The results show that a large amount of coolant contamination has been removed by SCCO₂. In addition, the results also show that the cleaning efficiency for residual coolant with SCCO₂ can be further enhanced by the addition of entrainers, including methanol and ethanol. (authors)

[en] The residual coolant on the surface of uranium after manufacture is inevitable and it will be effective on the corrosion of uranium. IR and Raman spectra were used to investigate the contamination on the uranium surface in this study. The results show that Raman spectrum and infrared spectrum can distinguish the contamination species and determine the amount of contamination. The results also show that the distribution of contamination is not uniform. (authors)

[en] The experimental study on uranium corrosion was carried out over a range of 50-90 degree C and 32%-86% relative humidity of thermogravimetry (TG). The corrosion degree of uranium-water vapor reaction was evaluated by weighing sample weight gain at appropriate intervals. Under above experimental conditions, the characteristic of uranium corrosion was observed and its kinetics was also discussed. The results indicate that there are three stages in the uranium-water vapor oxidation reaction at various temperatures. First, there is an initial reaction stage followed by the corrosion rate tends to be slow down after the first corrosion stage. At the third stage, the corrosion reaction presents to be a linear reacton with a stable oxidation reaction rate constant. The dynamics curves on the rear part of linear reaction stage are fitted, and the activation energy deduced is about 42.899 kJ·mol^-1 at RH=74.7%. Uranium-water vapor reaction is faster at higher temperatures. The effect of relative humidity on the uranium-water reaction is about the same as that of temperature in the range of 70-90 degree C, but the further study on the effect of relative humidity below 60 degree C is necessary. (author)

[en] Cleaning effectiveness to uranium surface contaminants residual using supercritical carbon dioxide (SCCO₂) fluids has been studied. Cleaning experiments mainly focusing on the general and typical machining residual contaminants such as machine oil, water and triethanolamine are carried out. By X-ray diffraction (XRD) and Auger Electron Spectrometry (AES) methods, the SCCO₂ compatibility of uranium is investigated. Results of cleaning experiments show that both machine oil and water can be dissolved by SCCO₂ and cleaned up from uranium surface easily. Triethanolamine can't be dissolved by SCCO₂. XRD study reveals that there are only U and UO₂ at cleared uranium surface. AES result indicates that during cleaning, C and O can ingress into the surface layer of uranium sample. Air corrosion test shows the uranium specimen cleaned with SCCO₂ has a better corrosion resistance than specimen without SCCO₂ cleaning

[en] Influence of vacuum heat-treatment on the corrosion resistance of uranium surface overlaid with graphite at 100 degree C is studied. The results show that the graphite coat after vacuum heat treatment can protect the uranium surface. The corrosion resistance of uranium surface overlaid with graphite depends on the heat treatment time and temperature. It can be expected that the reaction product of uranium and graphite may be beneficial to improving the corrosion resistance for uranium surface. (authors)

[en] The corrosion resistance of uranium surface treated with supercritical carbon dioxide (SCCO₂) is studied by mass gain and electrochemical methods. The oxidation kinetics curves (Δm-t) of uranium surface treated with SCCO₂ is obtained at 60 degree C, 70% RH condition. The results show that the corrosion resistant of treated uranium in the researched pressure, time and temperature region is improved. The electrochemical corrosion resistance of treated uranium in the solution with the ω (Cl^-) =50 μg/g is also studied by electrochemical method. The result indicates that the electrochemical corrosion resistance of uranium surface is enhanced. It can be expected that the existence of the uranium carbide in the reaction products may be beneficial to improving of corrosion resistance for uranium surface